WO2001035154A1 - Method and device for effecting a three-dimensional display - Google Patents

Abstract

The invention relates to a method for three-dimensionally displaying scenes and/or objects according to which a number of tomographic images and/or parts of tomographic images, which contain information consisting of different three-dimensional depths of the scenes or of the objects, are presented in a visually perceptible manner. The invention also relates to devices for carrying out the inventive method. According to a method of the aforementioned type, the tomographic images or parts of the tomographic images are, in an object plane, reproduced next to one another in a simultaneous manner and/or are reproduced in succession in a cyclically rapid manner. The tomographic images or parts thereof are depicted in a real and/or virtual manner using a number of lens areas having different focal distances but, however, having a common optical axis. An image a1 is generated from a tomographic image b1 or from parts b11, b12 b1m of the tomographic image b1 via lens areas having the focal distance f1, and an image a2 is generated from a tomographic image b2 or from parts b21, b22 b2m of the tomographic image b2 via lens areas having a focal distance f2, etc., whereby the images a1, a2, etc. can be seen one behind the other on the optical axis and, as a result, can be perceived with three-dimensional depth.

Description

title

Method and arrangement for three-dimensional representation

FIELD OF THE INVENTION The invention relates to a method for the spatial representation of scenes and / or objects, in which several layer images and / or parts of layer images that contain information from different spatial depths of the scenes or the objects are presented visually perceptible furthermore relates to arrangements for carrying out the method according to the invention

State of the art

Procedures and arrangements in which spatial images are reproduced in a manner that increasingly corresponds to the natural viewing habits of a viewer are required in many areas of human activities, such as in technology, medicine, art, presentation, advertising, etc. From the natural viewing habits of humans, the procedures and arrangements known in the prior art for the spatial representation of objects can in principle be assigned to two groups

In the first group, the viewer must decouple accommodation and convergence from one another, which can lead to fatigue, headache and nausea if they are permanent. This group includes the well-known autostereoscopic and stereoscopic 3D methods. The latter have additional disadvantages in that the viewer has to wear special balls (Red-green, polarization or shutter balls) or even complete mini-displays (HMD, Head Mounted Displays) have to be accepted. A free choice of viewer position and / or the possibility of viewing by several observers is usually only possible with one or several complex tracking systems (Eye Trackmg System) achieved Although autostereoscopic 3-D processes do not require any help from the viewer, they are known to suffer from "dead" zones, "fhpping", pseudoscopy and unnatural image movement when moving the head

In the second group, the volume displays, there is no conflict between accommodation and convergence, since the spatial representation arises in a volume. In a first subgroup, mechanically moved components are required. A rotating phosphor-coated disk in a cathode-ray ball, rotating or Oscillating surfaces with LED matrices and also a helix that is irradiated and rotated by lasers. The disadvantages of these methods are the components that are moved with high mechanical loads, complicated control and the limited volume

In a second subgroup, images are optically imaged in a volume. This is achieved, for example, by an acoustically-modulated concave mirror, computer-generated holograms using an acousto-optic modulator or mercury vapor fluorescence with infrared excitation. These methods and arrangements are also relatively expensive and therefore costly. most connected

Known in this regard are also methods and arrangements in which slice images are optically imaged into the room by means of a multifocal lenticular array. JP 62-77 794 A describes an image generator which reproduces slice images in such a way that a viewer has a spatial view Image is perceptible For this purpose the imager has a plurality of columns and rows of the flat grid of lenses, the focal length of each lens can be changed independently of the neighboring lenses by separate control. The optical axes of these lenses are parallel aligned Each of the lenses corresponds to a section of an object plane of the imaging device in which the layer images are reproduced. The original spatial depth of a part of the picture reproduced in this section is used to change the focal length of the associated lens in such a way that those with the lens generated image This part of the image can be perceived by the viewer again in a corresponding spatial depth. The reproduction of the layer images and the focal length adjustment of the lenses are controlled and controlled by a computer This arrangement, in which the staggered images of the plane slice images are generated with the aid of lenses with parallel aligned optical axes, has the major disadvantage that each image part of a slice image shown must be positioned exactly on the optical axis of the associated lens. In addition, the image parts, corresponding to the imaging scale of the assigned lens, must be smaller than their image so that a complete and overlap-free image of the entire slice image can be produced.

This requires that all image parts of a layer image, even every pixel or each individual image information, must be processed with regard to their position and geometry in such a way that they fit exactly into the entire image of the layer image even after the axially symmetrical enlargement by the assigned lenses. This image processing requires a considerable amount of equipment.

Because the image parts or image information of the slice images do not completely fill the object plane, there is the further disadvantage that the viewing angle is limited and the images of the slice images are only spatially perceptible to one or very few viewers standing next to one another. Strictly speaking, therefore, a spatial perception that really corresponds to the viewing habits is only possible for one viewer in a single position, namely with a precise straight view at right angles to the lenticular grid.

The same applies to the arrangement according to JP 07-64 020 A. Here, several display elements, each equipped with a convex lens with a short focal length, a light source and a stretching mechanism located between the lens and the light source, are arranged on a display surface for the slice images. The slice images are displayed by changing the distance between the convex lens and the light source using the stretching mechanism, as a result of which the position of the image of the light source generated using the convex lens is shifted. This has the same disadvantages as in the publication mentioned above.

However, arrangements are also known from the prior art in which no such lenticular array arrangements with parallel optical axes of the lenses are required for imaging the slice images, but instead only a single imaging element is provided instead of the lenticular array. Such an arrangement is described for example in US 3,493,290 as a three-dimensional display. Here, a low-frequency-controlled, deformable, and thus changing its focal length, large concave mirror is synchronized with a monitor on which successive flat slice images are displayed and which has an extremely short afterglow duration, so that a three-dimensional image is created in the room with both eyes can be viewed over a wide viewing angle range.

However, with arrangements of this type there is a significant disadvantage in that mechanically moved and thus wear-prone assemblies are required, relatively high expenditure is required for the purpose of beam deflection and beam splitting and so-called “phantom images” or “ghost images” occur. In addition, there is a perspective distortion of the spatial image, which has its origin in the increasing magnification of the virtual images.

Arrangements are also known in which a switch array is used which is arranged near an imaging lens and a second lens is positioned at a distance from this switch array which corresponds to its focal length. This is a monofocal imaging lens, the image of which is created in the plane of the second lens. Such an arrangement is described in “A.R.L. Travis, S.R. Lang, The design and evaiuation of a CRT-based autostereoscopic 3D display, Proceedings of the SID, Vol. 32/4, 1991 ". Autostereoscopic SD display by means of time-azimuth multiplexing is thus achieved.

For the purpose of 3D representation, monofocal Fresnel lenses are also used in the prior art, which act optically as a field lens. An example of this can be found in EP 0 653 891 with a "three-dimensional projection display apparatus". The active edges of a monofocal Fresnel lens used as a field lens are also adapted to a further optical element. This can be, for example, a cylindrical lens screen, as in JP 092 74 1 59 "Stereoscopic image display divice".

The use of a bifocal and thus multifocal Fresnel lens for a rear projection screen which is equipped with a cylindrical lens array is specified in EP 0874 268 "Fresnel lens sheet and rear projection screen". Here, however, the Fresnel lens also acts as a field lens, which has the consequence that it does not provide staggered images. The use of a monofocal Fresnel lens is also described in a “device for displaying moving images in hermetically lying planes” according to WO 98/1 81 1 4. The disadvantage here is the high outlay in terms of equipment, since two image generators, a beam splitter and in addition to the monofocal Fresnel lens a concave mirror are all necessary for two levels, which not only results in high manufacturing costs, but also a relatively large construction volume

WO 98/1 0584, a “display system”, describes a method and a device for the simultaneous or alternating display of two images behind the other. Here, a first image source, which represents the foreground, and a second image source, which reproduces the background, are also described Superimposed on an overall scene with the help of an optical radiation plate known as "be am combiner", whereby the viewer perceives the background at a greater distance than the foreground and in this way receives a spatial impression. The monofocal Fresnel cylinder lenses or cylinder mirrors used here are only used for optical changes the aspect ratio between the foreground image and the background image

If, with this arrangement, more than two levels are to be displayed at different distances from one viewer, the already high expenditure increases considerably

Description of the invention Starting from this prior art, the object of the invention is to further develop a method of the type described in the introduction such that fatigue-free spatial perception adequate to human viewing habits is possible with good quality with little expenditure on equipment, and also the optical imaging devices suitable for this purpose , such as lenses or lens groups

According to the invention, it is provided that the layer images or parts of the layer images are displayed simultaneously next to one another and / or cyclically in rapid succession in an object plane and with several lens areas, which have different focal lengths, but have a common optical axis, the layer images or parts thereof in real and / or can be imaged virtually, whereby of a layer image b or of parts b. b, b of the layer image b by lens areas with the focal length f, an image a _)? a layer image b or parts b, bb of the layer image b through lens regions with a focal length f

Image a. is generated and so on and the images a ^ a. etc. visible in succession on the optical axis and thus perceptible in spatial depth

In this way, the disadvantages inherent in the methods known from the prior art are avoided. The slice images can be used in their entirety in their entirety or even in a grid, spatial representations of scenes / objects corresponding to the viewing habits arise without unnatural decoupling from Accommodation and convergence, which can be perceived visually in very good quality without aids. The technical expenditure for equipment is low, since neither a large number of imaging lenses with parallel optical axes nor moving components are required to carry out this process. Both two-dimensional slice images and three-dimensional autostereoscopic images can be seen reproduced on the image generator and used as the basis for spatial representations The perception is without restriction of the spatial impression of several viewers from any position within a relatively large solid angle possible without tools

For example, the slice images or parts of the slice images can be displayed simultaneously next to each other in the object plane and, for the purpose of generating an image of each slice image, their respective assignment to lens areas of a certain focal length can be seen depending on selected physical properties of the image height, such as wavelength and / or Polarization, in other words, properties of the image are used to assign only lens areas with one and the same optical focal length to each layer image or parts of the layer image. This also ensures that the layer images or their parts - corresponding to the assigned focal length - are depicted in different spatial depths, the spatial depth in which the image of a layer image appears in each case corresponds to its spatial depth in the scene or the object to be reproduced or this is at least proportional

Furthermore, according to the method according to the invention, it is also possible to generate spatial images in that the slice images are reproduced briefly one after the other in the object plane and this reproduction is repeated in rapid succession Each slice image or parts thereof are assigned exclusively lens areas of a certain focal length and thus an image of the respective slice image is generated again and again for a short time

Such a time, the slice will be during _t] example, b _| reproduce md in the same time period ^ to generate the image a only lens areas of the focal length f are used optically thereafter during a subsequent time period t_ the slice image b_ is reproduced and only use lens areas of the focal length f for the generation of the image a etc. the time periods t ^ t to t _n , which each form a sequence, are repeated cyclically and the same slice image is also reproduced in each time period, with only one focal length being assigned to each slice image or, conversely, only one slice image being assigned to each focal length

It is necessary that the release of the lens range to be assigned always takes place synchronously with the reproduction of the corresponding slice image, and the change of slice images and the changing release of the assigned lens areas is carried out so quickly that the resulting staggered images take into account the inertia of the eye f can be perceived without any problems

In a particularly preferred embodiment of the invention it is provided that, during a time period t, a partial number n _] of the total number n of all slice images available or on which the spatial image is based is initially reproduced simultaneously, the assignment of each within the time period t _] reproduced slice image (or parts thereof) for lens areas of a certain focal length, as already stated, depending on the wavelength and / or polarization of the imaging height. Subsequently, a partial number n. of the slice images (or parts of these) are simultaneously reproduced side by side, with their assignment to lens areas again depending on the wavelength and / or polarization of the light. Further time periods t, t etc. can now follow, in which further periods in the previous time periods are not yet shown provided slice images are played back until each of the total slice images that have been present has been reproduced once, each slice image clearly comprising lens regions finally have been assigned to a certain focal length and an image a _χ (x = ln) has been generated from each slice image or from its parts

Here, too, the time periods t ^ t. etc. cyclically repeated quickly, the same slice images always being reproduced ben within each of these time periods and reproduced in the manner described

The layer images reproduced during a time period can be assigned to lens areas of predetermined focal lengths by optically releasing only the lens areas required for imaging within this time period, while all lens areas not required are optically blocked

An advantageous application of the method according to the invention results if the layer images simultaneously displayed next to each other are not reproduced in their entirety but in part in the object plane.It is particularly advantageous to select strip-shaped sections of each layer image and to display them side by side Parts of two layer images b ₍ and b ₂ on the image generator, for example, alternately alternating one stripe b of the layer image b next to one stripe b of the layer image b_, then another stripe b _{] 2 of} the layer image b _t next to the next stripe b _{22 of} the layer image b ₂ etc. appear. This requires an imager of double width or with double horizontal resolution (half-width pixel). Therefore, the strip b _π of b _{] was} preferred next to the strip b of b, next to it the strip b of b, and next to it the strip b of b etc. appear

The invention further relates to arrangements for the spatial representation of scenes / objects according to the aforementioned method. According to the invention, such an arrangement has an imager that is suitable for layer images or parts of layer images simultaneously and / or cyclically one after the other in one and the same object plane reproduce as well as an image, which has a plurality of lens areas with different focal lengths but a common optical axis and which is arranged upstream of the imager in the direction of view of at least one viewer or camera. The imager also has means for temporally and / or spatially assigning one reproduced in the object plane Layer image b _ι (or reproduced parts thereof) to lens areas of a focal length f, one reproduced in the object plane given layer image b ₂ (or reproduced parts thereof) to lens areas of a focal length f, etc

If the imager is designed for the simultaneous reproduction of several slice images or parts thereof, polarization filters and / or color filters can be provided as a means for spatial allocation to lens areas of a certain focal length

For example, the imager may be configured so as to b in the object plane at the same time two images layer _ι and b is ₂ or parts of this slice images nebeneman- representing that can Abbildungseinπchtung f with lens portions of two different focal lengths and f. be equipped, the slice b or the parts thereof can be assigned polarization filters with the polarization 0 ° and the lens regions with the focal length f also polarization filters with the polarization 0 ^° , while the slice b or the parts of the slice b. and the lens areas of the focal length f. each polarization filter with the polarization 90 ^'are associated

In this way it is achieved that the part of the imaging beam path that starts from the sections of the object plane on which the image b _| or parts of it are shown, due to the polarization of the associated polarization filter is always assigned to the lens areas of the focal length f. This applies in an analogous manner to the part of the imaging beam path that comes from the sections of the object plane on which the image b ₂ or parts thereof Darge represents or on the assigned lens area of the focal length f The spatial depth of the slice images b and b and the assigned focal lengths f and f are coordinated with one another in such a way that the images actually take place in the given spatial depth and thus for the viewer are perceptible at this depth

A similar configuration of the arrangement can be achieved if color filters are used instead of the polarization filters. Thus, the arrangement according to the invention can be designed such that the imager is designed for the simultaneous reproduction of three slice images b., B ₂ , b ₃ , lens areas with three different focal lengths f, ff are provided and are each assigned to the slice images shown in the object level as well as to the assigned focal lengths color filters with the same optical properties. For example, the sections of the object level that the slice image b or parts of the slice image Play the b, a red filter and the lens areas f also be preceded by a red filter. In this way, the image of the slice b takes place in an imaging plane which (apart from the fixed object width) is given by the focal length f

The same applies analogously to the layer images b. and b to, which can be assigned to the focal lengths f and f in the same way by means of green and blue filters, respectively. Whoever is thus imaged at a depth that (apart from the fixed object width) is predetermined by the focal lengths f and f of the assigned lens areas

In a further embodiment of the arrangement, for example, a layer image b in the object plane can be assigned both a polarization filter, for example with the polarization 0 ^° , and a color filter, for example a red filter, while the lens regions of the focal length f have polarization filters in the same way ( the polarization 0 ^° ) and the color filter (red filter) are assigned. If polarizations of the polarization filters and spectral properties of the color filters are assigned to the layer images or lens regions in such a way, as is shown in a table in the example in claim 9, six different layer images b to b can be assigned Represent lens areas of six different focal lengths f to f in six images a to a, which are staggered in spatial depth according to the focal lengths f to f

The filters associated with the layer images are advantageously positioned directly on or at least near the object plane and the filters associated with the lens regions are positioned directly on or at least near the surface of the lens regions. In a particularly advantageous embodiment, the color and / or polarization filter layers associated with the lens regions are directly in the Aper ture level of the imaging arrangement

Of course, it is possible to use an image generator with a color display in the object. For this purpose, for example, a color monitor can be provided which can then be controlled so that the layer images with light of different spectral properties appear on the monitor surface. For example, all parts of the layer image b will appear on the surface Radiated red on the monitor surface, they are assigned to the lens areas to which red filters are assigned A further embodiment of the invention provides that the imager is designed for the cyclical reproduction of the layer images or parts of the layer images and that a controllable shutter and a synchronous control are provided as means for temporally assigning a layer image reproduced in the object plane to lens regions of a certain focal length is provided, which is connected to both the imager and the shutter. The synchronous control ensures that the slice image b (or parts thereof) is reproduced in the object level of the imager during a period of time t _] and the shutter is controlled in such a way that that only lens areas of focal length f can be used to generate an image. During the following time period t, the imager is controlled so that slice image b ₂ (or parts thereof) appears and the shutter is controlled so that only lens areas of focal length f are used to generate an image v are available, etc

The shutter practically has the task of alternately releasing and blocking cross-sectional areas q ^ q ₂ q _{n of} the imaging beam path during the time periods t, tt _n , the released cross-sectional areas q, q or q always being the lens areas of the focal length f, f or f correspond to the

Creation of an image a, a ₂ or a _n of the slice image b ^ b ₂ or b _n reproduced in the respective time period t, t or t is to be used for this purpose. The shutter is expediently to be arranged at least approximately in the aperture plane of the imaging device

Such a shutter can be a flux modulator placed in the imaging beam path, in which a triggering of a flux region, the flat extent of which corresponds to such a cross-sectional area of the imaging beam, results in a change in the polarization direction for this cross-sectional area and thereby in cooperation with an im Imaging beam path upstream polarizer with a fixed polarization direction and a downstream analyzer, also with a fixed polarization direction, for the relevant cross-sectional area a change in transparency is effected. In the activated state, the transparency can be the maximum and in the non-activated state the minimum (black mode). or, alternatively and preferably, the transparency has the minimum in the activated state and the maximum in the non-activated state (white mode) due to the assignment of the cross-sectional regions to lens regions The focal lengths can thus be controlled to control the availability of the lens areas for the production of images LC shutters of this type consist, for example, of a first polarization film (as a polarizer) with the same polarizing effect over the entire surface, for example with the polarization direction 0 ^° , of an active polarization-optical part with separately controllable liquid flow areas and of a second polarization film (as analysis gate), also with the same polarizing effect over the entire surface. The fixed polarizations of the polarizer and analyzer can be rotated by 90 "relative to each other (white mode) or parallel (black mode)

In concrete versions, LC shutters from Jenoptik Laser / Optik / Systeme GmbH, Germany, and FLC shutters from Central Research Laboratories Limited (CRL), United Kingdom, can be used

In the manner described, it is achieved that the image change on the image generator and the release or blocking of the assigned cross-sectional areas always take place synchronously and the lens areas of corresponding focal lengths are thus also assigned to the respective slice images

The use of a multifocal Fresnel lens for realizing the lens areas is effective from an optical point of view and at the same time is advantageous in terms of production technology.For example, a multifocal Fresnel lens can be provided with lens areas of four different focal lengths f to f, which can be square, circular or also strip-shaped Implementation in that the Fresnel lens is designed as a multifocal Fresnel lens with stripe-shaped lens areas. Specific embodiments of multifocal Fresnel lenses, which were developed in particular in connection with the inventive arrangement described here and are suitable for use for this purpose, are discussed in more detail below

The layered image of the slice images is improved if, for the purpose of scale correction, for example in the viewing direction of the viewer or the camera, a monofocal Fresnel lens of focal length f is additionally arranged at a distance of this focal length in front of the multifocal Fresnel lens another, more complex way to change the scale It should be noted in the following to the possibility of a further embodiment of the invention, in which the multifocal Fresnel lens has lens areas with two different focal lengths f and f, which in turn can be square, circular, strip-shaped or otherwise shaped a Fresnel cylinder with stripe-shaped lens areas can be used

In principle, a liquid modulator modulator can also be used here as a shutter, which is constructed in the manner already described and in which individual liquid crystal regions, each corresponding to a cross-sectional region, can be controlled. In this case, however, lens regions are provided which differ only by two different focal lengths , A liquid modulator can advantageously be provided, in which there is also a first polarization film (as a polarizer) with the same polarizing effect over the entire surface, for example with the polarization direction 0 ^' , but the active polarization-optical part differs from that already described The construction does not have to have separately controllable liquid crystal areas corresponding to the cross-sectional areas, but can be designed so that when the liquid crystal stalls are actuated, the change in the polarization direction over the total cross section of the imaging beam nges is achieved and the second polarizing film, which acts as an analyzer, does not polarize the same area over the full area, but has polarization regions p _t and p ₂ , each with a polarizing effect rotated by 90 ° to one another

In other words, the polarization areas p _ι correspond to cross-sectional areas of the imaging beam path with a polarization direction 0 ^" and the polarization areas p_ correspond to cross-sectional areas of the imaging beam path with a polarization direction 90 ^° (or vice versa)

A change in transparency is thus achieved when controlling the liquid stalls for the relevant cross-sectional areas of the imaging beam path, the transparency again being the maximum in the activated state and the minimum in the activated state (black mode) or, alternatively and preferably, in the activated state the transparency can have the minimum and in the uncontrolled state the maximum (white mode)

An arrangement which is particularly suitable for producing a multiplicity of images staggered in depth is obtained when the image generator is for reproduction A partial number of slice images was formed during a time period t, a partial number n of further slice images during a time period t, and so on

For example, the arrangement can be designed in such a way that the imager of a total number of n = 4 slice images shows a partial number n _ι = 2, consisting of slice images b, b ₂ , over a period of time t, thereafter during a period of time t. a Teilanzahi n ₂ = 2, consisting b from the layer images, b represents and different in the Abbildungsemπchtung four lens areas focal length f provided to f are Further, in this context, game .weise examples the layer image _b] polarizing plate with the polarization direction of 0 'and the lens portions polarization filters with polarization direction 0 ^{"can also be} associated with the focal length f, as a result of which the optical assignment of the layer image of the b _t to the lens regions of the focal length f is ensured. The assignment of the layer image b likewise reproduced within the time period t. to lens regions of the focal length f in an analogous manner by polarization filters of 90 ^° polarization direction

In an analogous manner, polarization filters with a polarization direction of 0 ^{° are used} to assign the layer image b to lens regions of the focal length f and polarization filters

Direction of polarization 90 ^° for assigning the slice image b ₄ to lens areas of the focal length f is available. The consequence of further time periods t, t to t with reproductions and assignment of a further two slice images is conceivable

In connection with the design variants of the invention, in which the simultaneous reproduction of several layer images is provided and polarization filters are used to assign the layer images to lens regions of a predetermined focal length, the polarization filters can be used, for example, as linear polarization filters or as circular polarization filters with right and left rotating polarization directions be trained

It is recommended to operate the synchronous control with a clock frequency f which is above the multiple of the flicker fusion frequency v _{Au e of} the eye and which is preferably f,> v * n / l, with n the total number of slice images and I the number of slice images reproduced simultaneously per time period t _χ This ensures that a viewer-free image can be perceived for the viewer or viewers Both the dynamic variant of the invention (spatial representation based on a large number of layer images with rapid image change) and the static variant (spatial representation based on layer images that are permanently reproduced at the same time) are suitable as imaging devices, the arrangements known in the prior art, such as CRT (Cathode Ray Tube) monitors, preferably with high resolution, high luminance and high refresh rate with low persistence (persistence). Further flat screens such as LC (Liquid Crystal) displays or projectors, preferably TFT (Thm Film Transistor) -LC- Displays or - projectors with TN (Twisted Nematιc) -LC and active control, LC displays or projectors in IPS (In Plane Switchmg) mode, FLC (Ferroelectπc Liquid Crystal) - displays, each preferably with high resolution, high luminance, high contrast and high refresh rate with low persistence, PP (plasma panel) displays, prefers large-area PPD, EL (Electrolummescence) displays, preferably colored ELD

These aforementioned image generators in particular meet the requirements that have to be met in connection with the cyclical full-surface representation of the layer images. Frequency problems can be overcome by using several graphics cards. If parts of layer images are to be displayed simultaneously next to one another, methods from the prior art, such as for example in autostereoscopic 3D displays with lenticular or Barπerean orders

Furthermore, an advantageous embodiment of the invention can consist in including the imager in the function of the shutter described, namely when the imager already has a polarizing image surface that is polarized across the entire surface, as is the case with an LC display, in particular a TFT-LC display the case is this image area can then take over the task of the polarizer of the shutter, which advantageously results in a simpler structure of the shutter or the entire arrangement

The invention also relates to multifocal Fresnel lenses for use in such configurations of the arrangement for the spatial representation of scenes and / or objects in which Fresnel lenses with lens areas or optical effective areas W _n are used, which are characterized by at least four different focal lengths f ( n = 1> 4) differentiate According to the invention, such a multifocal Fresnel lens is provided with a multiplicity of optical active surfaces W, which are assigned to at least four different categories n with regard to their focal lengths, each of the active surfaces W _n having the same focal length f, at least one category with a positive focal length and at least a category with a negative focal length is provided, adjacent active surfaces W _{n are} always immediately adjacent to one another with their respective edges and the Fresnel lens is designed as a flat plate or film with a substantially constant thickness

The complete avoidance of storefronts or flanks, which are arranged essentially at right angles to the main extension plane of the Fresnel lens, results on the one hand in a high optical efficiency, i.e. in particular a high translucency, and on the other hand simplifies the manufacturing technology Loose manufacturing form The design of the Fresnel lens as a flat plate allows the shaping of active surfaces that are assigned to a large number of different focal lengths, without this being associated with a considerable increase in the effort for the production. This allows very thin, surface-free multifocal lenses with a Width extension up to the order of about 2000 mm can be produced

In principle, it is possible to arrange the active surfaces assigned to the individual focal lengths next to one another at random, whereby systematic errors can be avoided. In many cases, however, it is advantageous to position the individual active surfaces with further devices of the optical arrangement, for example a shutter, a polarization grid, a color filter grid or the like, so that for this purpose the effective areas of the individual focal lengths are preferably arranged in a regular, repeating order

In order to avoid brightness fluctuations or vignetting, the effective areas are arranged in sequences in a advantageous embodiment, each sequence comprising exactly one effective area from each focal length category. The effective areas can be arranged in the individual sequences in any sequence. However, the sequence is preferred in all sequences the active area the same, which results in a very uniform brightness distribution without vignetting over the entire area of the lens

In a further, advantageous embodiment, active surfaces from categories with a positive focal length and active surfaces from categories with a negative focal length are arranged alternately next to one another and in immediate succession.As the active surfaces with positive and negative focal lengths are inclined in the opposite direction, the thickness fluctuation of the multifocal lens can be particularly varied keep low, so that a strong fissuring is avoided even in peripheral areas and good transparency is achieved

To reduce the thickness fluctuation, in a further advantageous embodiment, the number of categories with a positive focal length is equal to the number of categories with a negative focal length.If in this case, active surfaces with a positive focal length and active surfaces with a negative focal length are alternately arranged side by side, it can be done with the same width achieve a very even distribution of light across the individual categories

In a further embodiment, the active surfaces are designed as strips inclined to the main extension plane of the lens. These strips can, for example, be arranged in a line next to one another or also concentrically to one another. The sum of the widths of all active surfaces with a positive focal length projected onto a normal of the main extension plane essentially the same as the sum of the widths of all active surfaces with negative focal length projected onto the normal.As a result, the elevations and depressions resulting from the active surfaces largely cancel each other out.The individual strips of the active surfaces of the sequence that have a line at a distance of 1 swept 50 mm from the optical axis can, for example, be dimensioned according to the following regulation

n α d h

1 33, 4621 ^° 0.0226 mm 0.0342 mm

2 -9.401 9 ^° -0.0089 mm 0.0540 mm

3 1 5, 2659 ^° 0.01 1 9 mm 0.0435 mm 4 -23, 0060 ^' -0.0255 mm 0.0601 mm where n indicates the number mdex of the focal length category, α _n the effective flank angle between the relevant effective surface and the main extension plane, d the width of the relevant active surface projected onto the normal to the main extension plane, and h _n the width of the relevant active surface projected onto the main extension plane

If a sequence of active surfaces contains exactly one active surface from one of the four focal length categories, then as can be seen from the table above, the widths of the active surfaces with the numerical index 1 and 3 projected on the normal to the main extension plane rise above this sequence with a positive focal length against those of the active surfaces with the numerical index 2 and 4 with a negative focal length. In this case, the individual strips have a different width, depending on the focal length category, projected onto the main extension plane

In an alternative embodiment variant, on the other hand, the projection of the width of the stripes on the main extension level is kept the same for all categories of active surfaces.This is particularly advantageous if the individual active surfaces are to be optically activated or deactivated with the aid of an upstream or downstream shutter has a grid structure with a constant row and / or column width, the grid elements can be opened and closed individually or in groups. The strips of a sequence at a distance of 1 50 mm from the optical axis are then designed, for example, according to the following regulation

n α d _n h

1 33, 4621 ^° 0.0330 mm 0.0500 mm

2 - 9.401 9 ^° -0.0083 mm 0.0500 mm

3 1 5, 2659 ^° 0.01 36 mm 0.0500 mm

4 - 23, 0060 ^° -0.021 2 mm 0.0500 mm

where n again specifies the number mdex of the focal length category, α the active flanks wmkel between the relevant active surface and the main extension plane, d the width of the active surface projected onto the normal to the main extension plane, and h _n the width of the relevant active surface projected onto the main extension plane Furthermore, it is possible to design the active surfaces as strips in such a way that the projection of the width of the strips onto the main plane of extension corresponds to an integer multiple of a reference size for all categories of active surfaces, the reference size preferably being the width of the narrowest strip. Also in this case the effective surfaces can then be operated particularly simply with the shutter already mentioned above

For example, one of the active surfaces assigned to a negative focal length can be formed with twice the projected width h _n . The strips of a sequence at a distance of 1 50 mm from the optical axis can then be designed in this case in accordance with the following regulation

n α d h

1 33, 4621 ^° 0.0330 mm 0.0500 mm 2 -9.401 9 ^° -0.0083 mm 0.0500 mm

3 1 5, 2659 ^° 0.01 36 mm 0.0500 mm

4 -23.0060 ^° -0.0425mm 0.1000mm

the parameters n, α _n , d _n and h _{n are} again as defined above

Furthermore, it is also possible to form a strip with three times the projected width h _n , for example by designing the effective surfaces of the sequence lying at a distance of 1 50 mm from the optical axis according to the following regulation

n d h

1 33, 4621 ^° 0.0330 mm 0.0500 mm

2 -9.401 9 ^° -0.0248 mm 0.1500 mm

3 1 5, 2659 ^° 0.01 36 mm 0.0500 mm 4 -23, 0060 ^° -0.021 2 mm 0.0500 mm

where the parameters n, α, d and h are as defined above

A very uniform thickness also results in a sequence which is at a distance of 150 mm from the optical axis and whose effective surfaces W are dimensioned in accordance with the following regulation n α ie

1 29, 5063 ^° 0.02830 mm 0.05 mm

2 1 2, 1 576 ^° 0.021 54 mm 0.10 mm

3 -1 0.8855 ^° -0.00962 mm 0.05 mm 4 -24.521 1 ^° -0.02281 mm 0.05 mm

where n corresponds to the number index of the category, α the effective flank angle between the relevant effective area W _n and the main extension plane, d corresponds to the width of the active area projected onto the normal to the main extension plane and h corresponds to the width of the relevant active area projected onto the main extension plane

The multifocal lenses described above can be used as Fresnel lenses with no flanks, in which the strips form concentric rings. In view of the use in the arrangement for spatial representation, however, the multifocal lens is preferably designed as a Fresnel cylinder lenses without flanks with active surfaces running parallel to one another

Furthermore, it is advantageous to choose the width of the active areas smaller than the resolution of the human eye so that the structuring of the lens does not impair the quality of the observation. Small structures also reduce the residual aberrations of asphaπscher multifocal Fresnel lenses and Fresnelzylmderlinsen Select the limit of the effective area width in such a way that diffraction phenomena in the range of visible light are avoided

In a further advantageous embodiment, the active surfaces are formed only on one side of the lens body, preferably on the image side thereof, whereas the opposite side is designed as a strictly flat surface. However, the invention is not limited to flat substrate surfaces. Rather, active surfaces can also be on one provide a curved substrate

In a further special embodiment of the multifocal Fresnel lens, the total area of the Fresnel lens is divided into a number of strip-shaped sectors S, with sections of effective areas W of the same focal length f within each sector S and S sections of within adjacent sectors S

Real W of different focal lengths f are present. M denotes a continuous number index for the sectors S. Because of the stripe-shaped structure, which is superimposed on the curved, preferably annularly arranged active surfaces W _n , "shutters" is possible with commercially available devices, as will be shown in detail below

The formation of curved active surfaces W with different focal lengths f is possible in the individual sectors S without the production expenditure for the multifocal Fresnel lens according to the invention being significantly increased compared to a Fresnel lens known from the prior art commercially available shutters of the type described, it is thus possible to capture a large number of different layer images with technologically simple to produce means and to be able to manufacture the corresponding optical arrangements more cost-effectively

The active surfaces W _n are preferably uniformly curved and arranged concentrically to one another, and the sectors S _mn are rectilinear and aligned parallel to one another. Furthermore, it is advantageous to choose the same width for all sectors S in order to reduce the technological complexity in the production of the Fresnel lens to be kept as low as possible. Furthermore, the projection of all active surfaces W _n involved in the image formation onto a reference plane is kept the same size. Furthermore, the coupling of a shutter, which usually has a grid structure of rows and / or columns of the same width, is better possible

This embodiment of the Fresnel lens is also advantageously designed as a flat plate or film with a substantially constant thickness. In order to be able to optimally use the total area of the Fresnel lens, the active surfaces W _n should always be immediately adjacent to one another within a sector S while avoiding interference flanks

For the visualization of image information, it is also advantageous if the widths of the effective areas W or their distances from one another are smaller than the visual one

Resolving power of the human eye Moreover, it is also advantageous if the greatest possible number m of sectors S are used because this minimizes imaging errors which are caused by the missing effective areas of the individual focal lengths f According to the invention, the following method steps are provided for producing such a multifocal Fresnel lens

First, the basic body of the Fresnel lens is made as a blank, which already has a flat surface which is intended as a later optically effective surface. The surface must be plastically deformable, and a plurality of press punches P _{n are also} produced which are suitable for plastically deforming the surface are, each of these press punches P having the negative structure of active surfaces W arranged in closed concentric circles of a focal length f, the press punches P _n are then separated into stamp strips, the stamp strips in shape and dimension each having a sector S on the Fresnel lens to be produced correspond, individual stamp strips are now strung together to form one or more differently composed press stamps P, the negative structure of active surfaces W having the same focal length f being present within each stamp strip and star-strip strips bordering one another with active surfaces W _n below different focal lengths f are provided

Finally, the surface of the blank is replaced by placing a combined press ram? _n and the action on the surface deformed under pressure until the structures of the active surfaces W are plastically embossed into the surface

Since initially f for each focal length _n, a separate press die P _n is prepared, can be prepared by separation of the press die P _n in the stamping strips by nachfol constricting joining of stamp strip having active surfaces W _n of different focal lengths f _n to vielfaltige manner combined composite press die P _n prepared so that depending on the intended use, press ram P ^' for Fresnel lenses with different optical properties can be manufactured

It is advisable to provide copper, aluminum or selected non-ferrous metals as the material for the press rams and to structure the press rams P with a single-point diamond cutting tool, for example on an NC lathe

A polymer material, for example PMMA, can be provided as the material for the Fresnel lens, with which the structuring by hot forming is possible Brief description of the drawings

The method according to the invention and the associated arrangements for the spatial representation of scenes and / or objects are to be explained below with reference to several exemplary embodiments. Show in the associated drawings

1 shows the schematic representation of an exemplary embodiment for generating a spatial image from four flat layer images which are reproduced cyclically one after the other over the entire surface,

2 shows the arrangement of lens regions from FIG. 1 in a high magnification,

3 shows the arrangement of cross-sectional areas of the imaging beam path with changeable transparency from FIG. 1 in high magnification, FIG. 4 shows the schematic representation of a second exemplary embodiment for producing a spatial image from two flat layer images which are reproduced cyclically one after the other over the entire surface, FIG. 5 shows the arrangement of lens areas from FIG. 4 in strong magnification,

6 shows the arrangement of cross-sectional areas of the imaging beam path with changeable transparency from FIG. 4 in high magnification, FIG. 7 shows the schematic representation of a third exemplary embodiment

Generation of a spatial image from four flat, full-surface cyclically reproduced slice images using a monofocal Fresnel lens in addition to the multifocal lens in the illustration, FIG. 8 shows the schematic representation of a fourth exemplary embodiment

Generation of a spatial image from four flat, full-surface cyclically reproduced slice images using a multifocal Fresnel cylinder lens in the imaging device, FIG. 9 shows a schematic, greatly enlarged representation of the active lens areas or that of a first exemplary embodiment of a multifocal lens for the arrangement according to FIG. 8 1 is a schematic, greatly enlarged representation of the raster structure of the shutter indicated in FIG. 8, FIG. 1 is a greatly enlarged partial sectional view through the edge region of the first exemplary embodiment of the multifocal lens, which can be used in the arrangement shown in FIG. 8, 1 shows a greatly enlarged partial sectional view through the edge region of a second exemplary embodiment of a muht-focal lens which can be used in the arrangement shown in FIG. 8 and has an active surface structure corresponding to FIG. 9, FIG. 1 shows the schematic illustration of a multifocal Fresnel lens with the

Effective areas W, W. W, W, which each have the focal lengths f, f, f, f, the total area of the Fresnel lens being divided into sectors S.

Fig. 1 4 shows the structures of four press rams P, P, P, P for generating active surfaces W _t , W ₂ , W ₃ , W ₄ with a hint of their dividing lines in individual

Stamp strips

Fig. 5 from individual stamp strips differently combined press stamps P, P,, P,, P for the production of differently acting Fresnel lenses

Detailed description of the drawings

1 shows an embodiment of the invention with an image generator 1, which is designed to display four flat layer images b _{] T} b_, b ₃ and b, - over the entire surface and cyclically following one another - each of these layer images b to b ₄ is the imager is reduced or enlarged by the factor α / β, in which an image scale ß _t to ß _{4 is} assigned to each slice image b _} to b ₄ , with which the transformation takes place through the multifocal Fresnel lens 2. α is a constant

The multifocal Fresnel lens 2 provided here has square lens areas with four different focal lengths f to f. These lens areas are in their

Positioning with respect to one another in FIG. 2 in a greatly enlarged section from FIG

Fresnel lens 2 is shown and labeled f to f according to its different focal lengths. For example, in FIG. 2 active edges 2a of the Fresnel lens 2 are drawn in as concentric circles, which have their center at the point of intersection 5a of the optical axis through the multifocal Fresnel lens, which is likewise exemplary in FIG The puncture point 5a is located, for example, at the borders of adjacent lens areas

In FIG. 1, a shutter 3 is also shown symbolically, which shows the transparency of individual cross-sectional areas q ₎ to q _{4 of} the imaging beam path from one dimension. ximum changed to a minimum and vice versa, in fact at the same time interval in which the slice images on the image generator 1 appear cyclically one after the other. The lens regions f to f also have those realized with the shutter 3

Cross-sectional areas q, to q ₄ square shape and extension The arrangement of the cross-sectional areas q _t to q ₄ and their positioning relative to one another is shown by way of example in FIG. 3, namely enlarged to the same extent as the lens areas in FIG. 2

The change in the transparency for the cross-sectional areas q _] to q ₄ is achieved by, for example, placing a liquid flow modulator in the imaging beam path as the shutter 3, which (in the direction of the beam path) is a polarizer with an unchangeable and rectified direction over the entire imaging beam path Direction of polarization, an active polarization-optical liquid stall zone in which individual liquid crystal regions can be controlled and which includes an analyzer (likewise with unchangeable polarization direction aligned over the entire imaging beam path). Depending on the mode of operation specified for the liquid stall modulator, "white mode" or " black mode "the polarizations of polarizer and analyzer are rotated by 90 ^° relative to each other or aligned in parallel (see previous description of the invention). Polarizer and analyzer are in commercially available liquid modulator Ren of such a type often designed as polarizing films, whereby a compact design of the modulator is possible

The shape and extent of the controllable liquid crystal areas also correspond to the cross-sectional areas q ₍ to q _{4 of} the imaging beam path, and each controllable liquid crystal area is assigned to one of the cross-sectional areas q _t to q _4. This ensures that when a liquid crystal area is controlled due to the interaction of polarizer , Fligkπstallen this area (whose polarizing effect can be changed with the control) and analyzer let the transparency for the assigned cross-sectional area q to q _{4 change} from a minimum to a maximum or vice versa. The polarizations of the polarizer and analyzer are preferably rotated so that the Transparency of the cross-sectional areas q _] to q _{4 has} the minimum in the activated state of the liquid stalls and the maximum in the non-activated state (white mode) In this exemplary embodiment, the multifocal Fresnel lens 2 and the shutter 3 are combined to form a structural unit. A strip-shaped active surface W of the multifocal Fresnel lens 2 is assigned a strip-shaped cross-sectional area q of the shutter 3, so that the individual active surfaces are specifically opened using the shutter 3 and can be closed

Imager 1 and shutter 3 are connected to a synchronous control system, which is not shown in the drawing. The synchronous control system ensures that, at the same time as a layer image is being reproduced, only the liquid crystal regions of the shutter 3 that control the path of the imaging beam path through those assigned to this layer image are not activated Lens areas should be released (white mode)

So in a first period t. the reduced (or enlarged) flat layer image b is transformed into a real image a _] by clearing the path for the imaging beam path through the square lens areas of focal length f. The remaining square lens areas of focal lengths f, f and f are during the time period t _ι blocked

During a subsequent second time period t, the reduced (or enlarged) flat layer image b appears on the image sensor 1, and synchronously in the cross-sectional areas q ₂ the path for the imaging beam path through the square lens areas of the focal length f is free, while the transverse intersection areas q, q and q are blocked for the imaging beam path. The layer image b is transformed into the real image a

In the third period t the layer image b is reproduced by the imager 1 and the shutter 3 is controlled synchronously so that the cross-sectional areas q release all lens areas with the focal length f, while the cross-sectional areas q, q and q all lens areas or effective areas of the focal length Block f, f and f or prevent their use by the imaging beam path. Thus, the layer image b is transformed into the real image a. During a time period t, the same is done in a figurative sense with the layer image b, of which an image a is created

The images a to a arise due to the different focal lengths f to f at different distances from the viewer 4 and are due to the dimension Correction of the bar, which in the Fresnel cylinder lens provided here only takes place transversely to the strip-shaped active surfaces, is the same size

For example, the distances from the viewer 4 correspond to the respective natural distance of the image information contained in the layer images b to b in spatial depth, because in addition the large ratios between the images a _t to a ₄ due to the scale correction remain unchanged as in the layer images b to b ₄ , the viewer 4 receives a spatial impression with a natural perspective as soon as his distance (up to a factor x) corresponds to that when viewing the real scene or the real object (the acquisition of the layer images b ₎ to b ₄ from the real scene or the real object is subject to certain conditions, which will not be discussed in more detail here)

The sequence of the time periods t _] to t ₄ is repeated cyclically, with the slice images b _t to b ₄ being repeatedly shown in the object plane of the imager 1 and images a _] to a _{4 being} generated in the same manner. The time periods are related ch selected according to their duration and chronological sequence and the time cycle is above n times the flicker fusion frequency v des

Eye, where n corresponds to the total number of slice images provided for the creation of spatial images (in this case n = 4), the viewer can perceive four flicker-free, real and / or virtual images depending on the design of the optical arrangement in different depths of the room like real objects

Thanks to this spatial gradation of depth, the viewer does not have to be satisfied with an illusion of depth, as is the case with the stereoscopic and autostereoscopic 3D methods. With the arrangement according to the invention, the viewer's eyes accomodate and converge on d> e Images in full accordance with their natural viewing habits without the need for decoupling Large-format Fresnel lenses are advantageously used so that the images can be seen in the room under a wide range of visual fluctuations.Therefore, multiple observers can view the images at the same time and for each viewer at the same time Experience of the movement paralax included, provided that it moves back and forth within the visual range. Further essential advantages are that no observer-related aids, such as glasses, are required and the process moves without e mechanical assemblies For the sake of clarity and in order to make it easier to compare the individual exemplary embodiments with one another, the reference numerals are used, as in the previous description part 1, for the imager, 2 for the Fresnel lens, 3 for the shutter, 4 for the observer, 5 for the optical axis and the designations b _χ for the slice images, f for the lens areas or focal lengths of the lens areas, q for the cross-sectional areas and a _χ for the images also retained in the following exemplary embodiments

Accordingly, the multifocal Fresnel lens 2 in the case of a second exemplary embodiment according to FIG. 4 has square areas with two different focal lengths f and f. In principle, in this case, the shutter 3 can be the same

Flussigkπstall modulator, as described in the exemplary embodiment of FIG. 1, are used, but since lens regions are provided here which differ only by two different focal lengths, a liquid crystal modulator can advantageously be provided, which has a polarizer (again with an unchangeable and over the entire imaging beam path of the same direction of polarization), an active polarization-optical liquid stall zone with (different from the first exemplary embodiment) uniformly controllable liquid stalls over the entire cross-section of the imaging beam path and an analyzer i 'm which (also different from the first exemplary embodiment) comprises individual polarization regions p ₎ and p has, which differ by up to today ver 90 ^"turned polarization directions of the two-dimensional extent of a Pola πsationsbereiches p _ι or p ₂ corresponds to a respective cross-sectional area of the imaging beam nganges, which is released or blocked by the shutter depending on the reproduction of the layer images

If the Flussigkπstalle are controlled, due to the interaction of the polarizer, the Flussigkπstall zone (the polarizing effect of which can be varied with the control) and the analyzer, the transparency for the cross-sectional areas of the imaging beam path which are respectively assigned to a polarization area pp ₂ becomes a minimum changed to a maximum and vice versa In this case, too, the polarizations of the polarizer and analyzer are preferably rotated relative to one another, so that the transparency in the activated state of the liquid crystals has the minimum and in the non-activated state the maximum, ie the liquid crystal modulator in “white mode” is operated In embodiments of the invention in which the imager already has a polarizing image area, as is the case for example with an LC display, in particular a TFT-LC display, this image area can take over the function of the polarizer of the shutter 3, which is very advantageous As a result, the shutter 3 can be constructed more simply. In addition, this results in the possibility of positioning the active polarization-optical liquid zone separately from the polarizer and analyzer at the point of the narrowest constriction of the imaging beam path, so that active polarization-optical liquid zones of small size can be used

Here, too, for the purpose of synchronous control, shutter 3 and imager 1 are connected to the (not shown) synchronous control. When operating the arrangement, the shutter 3 is controlled so that the cross-sectional areas that are associated with the lens area are assigned the focal length f and the polarization areas p _] ent speak, within the time period t. in which the slice image b appears on the image generator 1, are transparent to the imaging beam path and for producing an image a _. The cross-sectional areas, which are assigned to the lens areas of the focal length f and correspond to the polarization areas p ₂ , are not available within this time period t ₍ for generating an image, since the polarization areas p _{2 are} non-transparent

The image a. the layer image b. arises in this case (if necessary, taking into account an imaging ratio predetermined by the factor β) as a real image at a distance from the viewer 4, which is essentially predetermined by the focal length f, apart from the fixed object width

After the period t _ι has elapsed, the synchronizer in a subsequent period t controls the imager 1 so that instead of the slice b _] the slice b _{2 is} reproduced and synchronously controls the shutter 3 so that the path for the imaging beam path through the polarization regions p. and thus is released through the lens areas of the focal length f and the image a of the layer image b _{2 is} generated, while within the time period t the cross-sectional areas of the imaging beam path which correspond to the lens areas of the focal length f and which correspond to the polarization areas p are blocked for the imaging beam path If these switchovers are repeated sufficiently quickly, two real images a ^ a _{2 of} the slice images b of equal size are formed on the optical axis 5 at different distances from the viewer and therefore spatially perceptible. , b ₂

5 shows, by way of example, a greatly enlarged section of the Fresnel lens 2 with the lens regions of the focal lengths f and f and, by way of example, active edges 2a drawn in with the penetration point 5a of the optical axis 5 through the Fresnel lens 2

FIG. 6 shows, likewise greatly enlarged, the square polarization regions p and p. For clarification, the polarization regions p, which are controlled in the “white mode” mode of operation and are thus non-transparent, are shown hatched

In a third embodiment variant according to FIG. 7, a further development of the embodiment variant according to FIG. 1 is shown. Here, a monofocal Fresnel lens 6 is additionally provided between the shutter 3 and the viewer 4. The optical axes 5 of the Fresnel lenses 2 and 6 overlap. The monofocal Fresnel lens - SE 6 is arranged at a distance z _{2 in} front of the multifocal Fresnel lens 2, where z corresponds to the focal length f of the monofocal Fresnel lens 6

This embodiment has the advantage that the optical system by the two

Fresnel lenses 2 and 6 are formed, regardless of the focal lengths f to f of the lens regions of the multifocal Fresnel lens 2 from layer images b to b of the same

Large images a to a ₄ always the same size generated at different depths. In addition, the same enlargement or reduction in relation to the layer images b to b can be achieved for all images a to a ₄ by making the focal length f of the monofocal Fresnel lens 6 larger or is selected to be smaller than the distance z between the object plane of the imaging device 1 and the multifocal Fresnel lens 2

A fourth exemplary embodiment is shown in FIG. 8 As in FIGS. 1 and 7, the imager 1 is again designed for the sequential reproduction of four slice images b to b

The multifocal Fresnel lens 2 provided here is designed in the manner of a Fresnel cylinder lens with no flanks and has categories of strip-shaped lenses areas or effective surfaces W to W with four different focal lengths f to f. These active surfaces W to W ₄ are shown in their position relative to one another in FIG. 9 in a greatly enlarged detail from the quadfocal Fresnel lens 2 on the effective active surfaces W to W ₄ there are mainly light refractions and, under certain circumstances, reflections including total reflections, but no diffractions

In agreement with this, the zones which can be changed when the shutter 3 is actuated from transparency minimum to transparency maximum (or vice versa) correspond to strip-shaped cross-sectional areas q ₁ to q ₄

FIG. 9 shows the strip-shaped lens regions of the focal lengths f to f and their assignment to one another, while FIG. 10, likewise in high magnification, shows a section with the released cross-sectional regions q and the blocked cross-sectional region q ₂ to q ₄ and their assignment to one another Here too, as in the exemplary embodiment according to FIG. 1, a cross-sectional area is assigned to a lens area. In addition, the piercing point 5a of the optical axis of the Fresnel lens 2 is shown by way of example in FIG. 9 through a lens area of focal length f and the associated active edges 2a are indicated

In the arrangement according to this exemplary embodiment, the four flat slice images b to b ₄ are again reproduced over the entire surface and in succession in a cyclical sequence on the image generator 1. For the purpose of scale correction or in order to produce images of the same size, each of the slice images also has an image scale ß to ß ₄ assigned, which again ensure that when imaging the slice images by the multifocal Fresnel cylinder lens 2 in the direction of the coordinate X, ie perpendicular to the active flanks 2a of the Fresnel cylinder lens 2, a reduction or enlargement (compression or expansion) according to the assigned scale β to On the other hand, ß ₄ arises. In the direction of the coordinate Y, the slice images retain their size and are reproduced in their original size using the ß = 1 scale

When operating the arrangement according to FIG. 8, the layer image b, which has been scaled in the first direction, is again converted into a (exemplary) real image a by opening the cross-sectional areas q _] from the strip-shaped lens areas of the focal length f. transformed The remaining stripe-shaped lens areas with the focal lengths f to f stand during the time period t due to the blocking of the corresponding cross-sectional areas q ₂ to q ₄ by the shutter 3 for generating an image not available in the subsequent time periods t to t ₄ (as already described) the associated slice images b ₂ to b ₄ are displayed by synchronous activation and Within the same period of time, the assigned cross-sectional areas q to q are also switched transparently, so that the imaging beam path can pass through lens areas of focal lengths f to f and the layer images b to b are transformed into images a to a

As a result, all images have the same size with different distances in the room in front of the viewer

The use of a Fresnel cylinder lens and in connection with it a shutter with stripe-shaped polarization areas has significant manufacturing technology advantages, since Fresnel lenses with parallel stripe-shaped lens areas and shutters with parallel stripe-shaped areas are much easier to manufacture than such assemblies with square areas

Finally, embodiments of the invention are also conceivable in which Fresnelzy imder lenses are used in combination with Fresnel lenses, for example by additionally using a monofocal Fresnel lens in the fourth exemplary embodiment, as illustrated and explained in the third exemplary embodiment

Good results in connection with the aforementioned exemplary embodiments can be achieved when using TFT (Thin Film Transistor) -FLC displays as image generators in conjunction with appropriately designed image memories and graphics cards and with LC shutters from Jenoptik Laser / Optik / Systeme GmbH Germany

Within the scope of the invention there are of course also arrangements in which the deeply staggered images or at least one of them represent temporally changed, possibly also moving image contents if the contents of the layer images are changed over time

Multifocal Fresnel lenses, which are particularly suitable for use in the arrangement according to FIG. 8, will be explained in more detail below First of all, a concrete example of a Fresnel lens without flanks. FIG. 1 shows a section through the edge region of such a Fresnel lens 2. This comprises a lens body 2b, which expands flatly in a main extension plane, in the form of a flat, thin-walled plate or film 3 mm edge lengths in the order of up to approximately 2000 mm possible. The Fresnel lens 2 is preferably made of a transparent plastic, such as PMMA

As can be seen in FIG. 1 1, a plurality of strip-shaped optical active surfaces W 1, W ₃ and W _{4 are} formed on one side surface 2 c of the lens body 2 b, whereas the opposite side surface of the lens body 2 b is strict flat surface or flat surface 2d is formed

The individual active surfaces W, W, W. and W have different active flank angles, α, α and α, respectively, the active flank angle α of the relevant active surface W being the angle between the main extension plane of the multifocal fresnel axis 2 and the relevant active flank W is defined

Each of the differently inclined active surfaces W ^ W ₂ , W and W ₄ is assigned to a certain focal length f, f, f and f. This is shown in FIG. 1 1 using the object rays drawn from an axis point of an object and the OS for the individual effective areas W drawn in to draw rays BS _n which run to the axis points of the corresponding lines or virtual images a, a, a ₌ and a here

In the multifocal Fresnel lens 2 shown by way of example in FIG. 1, the two active surfaces W ₍ and W _{3 are assigned} a positive focal length, the two active surfaces W ₂ and 1, on the other hand, are assigned a negative focal length. Furthermore, it can be seen that all active surfaces W, W. W ₃ and W connect directly to one another, so that step-like shoulders between the effective surfaces W _t , W _2> W ₃ and W _{4 are} completely avoided

The width of the effective surfaces W _n formed here in strips is chosen such that the sum of those projected onto the normal to the main extension plane

Widths d of the effective surfaces W and assigned to a positive focal length

W ₃ against the projections projected onto the normal to the main extension plane ten d of each of the negative focal lengths associated with the active surfaces W and W ₄ so that after a succession of the four differently inclined active surfaces W _t , W ₂ , W ₃ and W ₄ the multifocal Fresnel lens 2 again has the same overall thickness as at the beginning of the sequence

In the exemplary embodiment shown here, the sequence of the four active surfaces shown in FIG. 1 1 is repeated over the entire width of the multifocal Fresnel lens 2, so that the same number of tear-shaped active surfaces W _{n is} provided for each focal length category per sequence. The sequence of the active surfaces can be in the individual sequences also differ from the illustrated embodiment

It is also possible to change the sequence of the individual active edges W _n randomly from sequence to sequence in order to avoid systematic imaging errors

In the quadfocal Fres nellmse shown in the exemplary embodiment according to FIG. 1, the individual active edges W of the sequence lying directly on the outer edge of the Fressellellse 2 are dimensioned in the following manner

n α ie _n

1 33, 4621 ^° 0.0226 mm 0.0342 mm

2 -9.401 9 ^° -0.0089 mm 0.0540 mm

3 1 5, 2659 ^° 0.01 1 9 mm 0.0435 mm

4 -23, 0060 ^° -0.0255 mm 0.0601 mm

The Fresnel lens 2 here has a diameter of 300 mm, so that this sequence is at a distance of 1 50 mm from the centrally arranged optical axis 5, where n is the numerical index of the active surfaces W _n , where n stands for one of the 4 focal length categories here The value α _n indicates the effective flank angle between the relevant effective surface W _n and the main extension plane of the Lmsenkorpers 2 b, d sets the projected width of the effective surface W to a normal to that

Main plane of extension, h _n , on the other hand, indicates the width of the relevant effective area W projected onto the main plane of extension

Towards the optical axis, the given angles of the respective focal length categories decrease the amount for further effective areas of a focal length category ab Active surface peaks or active surface troughs formed at the borders between adjacent active surfaces do not necessarily have to lie in a plane perpendicular to the optical axis

In a first variant of the first exemplary embodiment, the width h _n projected onto the main extension plane is the same for all active surfaces. While maintaining the active flank angles, which result from the four focal lengths chosen for the Fresnel lens 2, the individual active surfaces W are then directly marginal sequence as dimension rule

n α d h

1 33.4621 ° 0.0330 mm 0.0500 mm

2 - 9.401 9 ^° -0.0083 mm 0.0500 mm

3 1 5, 2659 ^° 0.01 36 mm 0.0500 mm

4 - 23, 0060 ^° -0.021 2 mm 0.0500 mm

However, this results in a relatively large change in total thickness of four different effective areas W., W, W and W per sequence

0.01 72 mm, so that such a lens, which is easier to manufacture because of the constant projected strip widths, is only suitable for smaller lens diameters

The increase in thickness can be reduced by producing one or more of the active surfaces W _n with an integer multiple, for example twice or three times the projected width h of the other active surfaces

In a further embodiment variant, the projected width of the effective area W is doubled for this purpose, so that there is a dimensioning requirement for the effective areas W _{n of} the edge sequence

n α d h

1 33, 4621 ^° 0.0330 mm 0.0500 mm

2 -9.401 9 ^° -0.0083 mm 0.0500 mm 3 1 5, 2659 ^° 0.01 36 mm 0.0500 mm

4 -23.0060 ^° -0.0425mm 0.1000mm The resulting change in thickness over a sequence of four different effective areas W, W, W and W is then considerably less than in the first embodiment. In the second embodiment, it is only -0.0040 mm

In a third embodiment of the first exemplary embodiment, the width of the second effective area W _{2 is} tripled compared to the other effective areas, so that a very slight expansion of 0.0006 mm occurs over the edge sequence of four different effective areas W for the third embodiment variant, the following dimensioning requirements

n α d h

1 33, 4621 ^° 0.0330 mm 0.0500 mm

2 -9.401 9 ^° -0.0248 mm 0.1500 mm

3 1 5, 2659 ^° 0.01 36 mm 0.0500 mm

4 -23, 0060 ^° -0.02 1 2 mm 0.0500 mm

A second example of an aspheric multifocal Fresnel lens 2 that can be used in the arrangement according to FIG. 8 is described below. This Fresnel lens is shown in sections in FIG. 1 2. In contrast to the first exemplary embodiment, the quadfocal Fresnel lens 2 according to FIG. 1 is designed as a Fresnel lens. whose active surfaces W ^ W ₂ , W ₃ and W n are arranged in concentric rings. The arrangement of the individual active surfaces W, W ₂ , W ₃ and W ₄ next to one another can in principle take place in the manner already explained above however, in an active area sequence from four different focal length categories, the respective active areas are directly adjacent to one another, which are assigned focal length categories with the same sign. In FIG. 1, the two outer and directly adjacent active areas W, W _{2 have} a positive focal length, which other Effective areas W ₃ and W _{4 of} the same sequence, which also directly adjoin one another, but negative focal lengths

In analogy to the dimensioning prescriptions given above, depending on the incidence height h, ie the distance to the optical axis or the radius of the concentric rings, the following dimensioning prescriptions result for selected values h n α

Height of incidence h = l 50.00 mm

1 29.5063 ^° 0.02830 mm 0.05 mm

2 1 2, 1 576 ° 0.021 54 mm 0.10 mm

3 -1 0.8855 ^° -0.00962 mm 0.05 mm

4 -24.521 1 ^° -0.02281 mm 0.05 mm

Height of incidence h = 98.0 mm

1 20.8485 ^° 0.01 904 mm 0.05 mm

2 8.9077 ^° 0.01 567 mm 0.10 mm

3 -9.7274 ^° -0.00857mm 0.05mm

4 -27, 5343 ^° -0.02607 mm 0.05 mm

Height of incidence h = 0.25 mm

1 0.0570 ^° 0.00005 mm 0.05 mm

2 0.0203 ^° 0.00004 mm 0.10 mm

3 -001 30 ^° -0.00001 mm 0.05 mm

4 -0.0346 ^° -0.00003 mm 0.05 mm

As can be seen from the comparison of the values for exemplary height of incidence h, the effective flank angle α of the effective surfaces W takes in the direction of the optical

Axis ab Under the above conditions, the following distribution of the lens thickness d results depending on the incidence height h

h (mm) d (mm h (mm) d (mm)

150 3.00 70 4.38

140 3.63 60 4.07

130 4.12 50 3.70

120 4.48 40 3, 33

110 4.70 30 2, 97

100 4.79 20 2, 68

90 4.76 1 0 2, 50

80 4.62 0 2.43

It can be seen from the above table that the thickness of the Fresnel lens 2 varies by a maximum of 2.37 mm according to the second exemplary embodiment. The greatest thickness is achieved in a zone with an incidence height h of 97.75 mm, which The minimum thickness, however, in the center of the Fresnel lens 2 on the optical axis Letzlere is only slightly smaller than the thickness at the edge of the lens, which is 3 mm. At an incidence height h of 97.75 mm, the sum of the projected widths d of the active surface sequence located there is zero

By doubling the groove width h ₂ for the active surfaces W _{2 of} the second focal length group compared to the other active surfaces W, W or W, this results in a particularly small range of fluctuation in the lens thickness d. In the exemplary embodiment shown in FIG. 1, all active surfaces W _n with the same If the width h _n = 0.05 mm, then with a lens diameter of 300 mm there would be a fluctuation width of 4.4 mm, the thickness being 2.4 mm in the center and approximately 7 mm at the edge. that a particularly thin lens can be realized by optimizing the effective area widths. In view of the manufacturing conditions, integer multiples of a basic effective area width are generally suitable for this. When used in an arrangement according to FIG. 8, the raster structure of the shutter 3 also represents a significant influencing variable since the active surfaces W over the cross sectional areas of the shutter 3 _n ge opened to or closed side of the Mog friendliness, each effective area W _n its own cross-sectional area of the shutter 3 an inlet, it is also possible to have multiple active faces W _n to be driven via a cross sectional area of the shutter 3, and then the surfaces each Brennweitenberei- image information to be assigned is separated using suitable filters, for example polarization filters or color filters. In principle, it is also possible to assign a plurality of cross-sectional areas of the shutter 3 to an effective area W.

When used in an arrangement with a shutter according to FIG. 8, it is particularly advantageous if, instead of a flat substrate outer surface of the lens, a suitably curved surface is selected. This allows the generally flat shutter to be optically adapted to the active surfaces of the multifocal lens

Differences in brightness, which result from the different widths of the stripes or the different effective areas of the focal length categories, can be compensated for in the above-described arrangements for three-dimensional display by appropriate control of the imager 1 or else used for special effects The above-described multifocal Fresnel lens 2 is not limited to the number of four focal length categories. Rather, Fresnel lenses 2 with a larger number of positive and negative focal length categories can also be produced in large format because the thickness fluctuations and thus the maximum thickness can be further reduced to achieve a particularly small one Thickness fluctuations across the lens width may also be advantageous under certain circumstances to use an unequal number of effective areas with focal lengths with positive and negative signs for each sequence.If two focal length categories with the same focal length are introduced, the multiplication of the width of the provided in the above examples results, so to speak, as a special case relevant active areas These active areas do not have to be arranged directly next to one another, but can also be separated from one another by further active areas of the sequence

Instead of arranging the active surfaces W _n in parallel strips, as explained in connection with the first example and its variants, it is also possible to arrange them in the form of closed rings, in particular concentric circles, with step increments between adjacent ones in all cases Active areas over the entire lens can also be avoided. The structure of the second example can also be used for a cylindrical lens with strip-shaped active areas arranged parallel to one another. The large-area, thin-walled lenses that are possible in this way each have only active areas without interposed storages. The total area formed by the active areas leaves describe themselves by a constant mathematical function that cannot be differentiated only at the boundaries of the active surfaces

In contrast to this, the optically effective surface of a conventional Fresnel lens is discontinuous. However, the small thickness and mass that are also possible with those Fresnel lenses must be bought through discontinuities in the form of stor flanks and the associated disadvantages set out above

In a further example in Fig. 1 3 is a multifocal Fresnel lens 2 with uniformly curved optical active areas W., W ₂ , W ₃ , W ₄ represents the effective areas W _{] t} W, W, W ₄ have the four different focal lengths f , f, f, f auf The total area of the Fresnel lens 2 is divided into eight strip-shaped sectors S, with m = l 8 as a numerical index for the sectors and n = l 4 as an identifier for different focal lengths f. It should be noted that the payment index m = 8 was chosen for the purpose of explanation on the basis of the drawings. In practice, however, this payment index should be significantly higher and be, for example, m∞400

It can be seen from Fig. 1 3 that within the sectors S _n and S _{S] there are} only sections of active surfaces \ N_ with the focal length f. Analogously to this, within the sectors S and S _{62 there are} only sections of active surfaces W with the focal length f present and so on

The result of this is that within each sector S only sections of

Effective areas W of the same focal length f are present. On the other hand, other sectors S always have sections of effective areas W that are different

Focal lengths f on The strip-shaped sectors S each have the same width, run parallel to one another and are joined together without gaps

Like the sectors S on the Fresnel lens 2, the cross-sectional areas q _t to q ₄ realized with the shutter 3 are also formed in a strip shape (see FIG. 10).

The multifocal Fresnel lens 2 and the shutter 3 can also advantageously be combined to form a structural unit. One sector S is included

Active areas W of a given focal length f on the multifocal Fresnel lens 2 are assigned to the strip-shaped cross-sectional area q ₁ to q ₄ on the shutter 3

A method for producing the Fresnel lens 2, as shown in FIG. 1 3, is explained in more detail below

For this purpose, four cylinder-shaped press rams P, P, P, P are first manufactured, of which the view of the shaped surfaces is shown in FIG. 1 4. The press ram P _{] T} shown in FIG. 1 4 a shows the negative structure of the annular active surfaces W _ι the Focal length f on The outer diameter of the surface shown corresponds to the dimension of the multifocal Fresnel lens to be manufactured 2. This applies to the remaining ram P, P, P ₄ , which are shown in Fig. 1 4b to 1 4d, figuratively

The structure of the active surfaces W _n is worked in, for example, with the aid of a diamond cutting tool. After the structuring, all the press punches P ₅ , PP, P are separated into stamp strips which, in terms of shape and area, correspond to the later sectors S _mn In FIGS. 1 4a to 1 4d, the dividing lines between the stamp strips are shown. With m the respective position of a stamp strip or sector is _. in the punch P and denoted by n the respective focal length f of the effective surfaces W.

After separating and, if necessary, after finishing the stamping strips, they are lined up to form combined press stamps P ^' , P ^' , P ^' , P _4. The resulting press stamps P ₎ , P_ ^' , P ^' , P ₄ are exemplified in FIGS. 1 5a to ₄ 1 5d outlined Here, the negative structure of active surfaces W _{n of the} same focal length f is present within each stamp strip, and adjacent stamp strips are provided with active surfaces W _{n of} different focal lengths f

In the final process step, in order to stay with the example of the Fresnel lens 2 selected at the outset, the press ram P ₍ ^{'' is used} to deform the surface of a blank of the Fresnel lens 2 by placing it on the surface and acting on the surface under pressure until the Structures of the effective surfaces W are plastically impressed into the surface

Deviating from this, the production of the Fresnel lens according to the invention is conceivable in such a way that a casting or injection mold is first produced which has the negative contours of the Fresnel lens and which is then repeatedly poured or sprayed out. Thermal plastic materials can be provided as lens material with this manufacturing process as well as with the one described above, for example Fresnel lenses of dimensions 1 231 x 727 mm ^{2 can be produced} in large numbers

Claims

claims

Method for the spatial representation of scenes and / or objects, in which several layer images and / or parts of layer images containing information from different spatial depths of the scenes or objects are presented to at least one viewer and / or at least one camera in a visually perceptible manner, characterized in that the slice images b _χ (x = ln) or parts thereof are displayed simultaneously next to one another and / or cyclically one after the other in an object plane and by means of a plurality of lens regions which have a common optical axis (5) but different focal lengths f (x = 1 n), the slice images b _χ (x = ln) reproduced in the object plane or parts thereof are mapped real and / or virtually by the slice image b ₍ or parts b, bb of the slice image b through lens areas of the focal length) f an image a, of the slice image b or of parts b, bb of the

Layer image b is generated by lens areas of focal length f and so on, wherein the images a _χ (x = ln) on the optical axis (5) are successively visible and perceptible in spatial depth

A method according to claim 1, characterized in that the layer image of b _χ (x = ln) or parts thereof in the object plane are simultaneously displayed next to each other, each layer image using physical properties of the imaging light, such as wavelength and / or polarization, Lens areas with a certain focal length can be assigned

Method according to claim 1, characterized in that the slice of the b _χ (x = ln) and / or parts thereof in the object plane are reproduced cyclically in succession and each slice is assigned lens areas with a specific focal length by only doing that during a time period t Layer image b or parts b, bb since reproduced and to produce an image a _. only the

Lens areas of focal length f are used, during a time period t, only the slice image b or parts b, b .. b thereof are reproduced and only the lens regions of the focal length f are used to generate an image a and so on until after a

Time period t _n all slice images b _χ (x = ln) or parts thereof have been reproduced and an image a _χ (x = l. N) has been generated from each slice image or its parts and then the time periods t, t ₂ , tt cyclically are repeated, the same slice image or the same parts of a slice image always being reproduced within each time period and the same lens regions or the same focal length being used to generate an image

A method according to claim 1, characterized in that initially a partial number n of the slices b _χ (x = ln) or parts thereof are reproduced simultaneously during a time period t _ι , each of these slices using physical properties of the imaging level, such as wavelength and / or polarization, lens areas with a certain focal length are assigned, subsequently during a time period t. a further partial number of the layer images b _χ (x = l. n) or parts thereof are reproduced simultaneously next to one another, lens areas with a certain focal length being assigned in the same way to each of these layer images, optionally following further partial numbers thereafter during further time periods t to t n ₃ to n of the slice images b _χ (x = ln) or parts thereof are simultaneously displayed side by side and lens areas of further focal lengths are assigned, where n _] + n ₂ + n + + n = n applies until each of the slice images b _χ (x = ln) has been reproduced once, each layer image has exclusively been assigned lens areas of a certain focal length and an image a _χ (x = ln) has been generated from each layer image or its parts and then the time periods t. , t, tt are repeated cyclically, the same partial number of slice images always being reproduced within each time period, and the unambiguous assignment of slice image and lens regions or focal length is always maintained Arrangement for the spatial representation of scenes and / or objects according to the aforementioned method claims, characterized by an image generator (1) which reproduces slice images b _χ (x = 1 n) or parts thereof simultaneously next to one another and / or cyclically in succession in an object plane, one Imaging device which has a plurality of lens areas of different focal lengths f _χ (x = ln), but all lens areas have a common optical axis (5) and the imaging device in the viewing direction of the at least one viewer (4) or the camera to the imager (1 ) is preceded by

Means for the temporal and / or spatial assignment of lens areas of a focal length f to a slice image b or parts b, bb of the slice image b reproduced in the object plane, for the temporal and / or spatial assignment of lens areas of a focal length f to an in Object plane reproduced slice image b or to reproduced parts b_, bb of the slice image b and so on

Arrangement according to Claim 5, characterized in that the imager (1) is designed for the simultaneous reproduction of layer images b _χ (x = ln) or parts thereof and as a means for spatially assigning lens regions of a certain focal length f _χ (x = ln ) polarization filters and / or color filters are provided for each of these layer images or for parts thereof

Arrangement according to Claim 6, in which the image generator (1) is designed for the simultaneous reproduction of two slice images b, b ₂ , lens regions with two different focal lengths f, f are provided and polarization filters are assigned as follows

Δ BC Ω__ b, 0 ^° f 0 °

90 ^° f 90 ^° where column A shows the layer images or parts of the layer images that are simultaneously displayed side by side in the object plane, column B the polarizations of polarization filters that are assigned to the layer images or parts of the layer images shown, column F the focal lengths of the assigned ones Lens areas and in column D the polarization direction of polarization filters which are assigned to the lens areas

Arrangement according to Claim 6, in which the imager (1) for the simultaneous reproduction of three slice images b ^ b ₂ , b. is configured, lens areas with three different focal lengths f, f, f. provided and color filters are assigned as follows

Δ BCD b red red b green r green b ₃ blue f blue whereby column A shows the layer images or parts of the layer images that are simultaneously displayed side by side in the object plane, column B the spectral property of color filters that assigns the reproduced layer images or parts of the layer images are, in column C the focal lengths assigned to lens areas and in column D the spectral property of color filters which are assigned to the lens areas

Arrangement according to Claim 6, in which the image generator (1) is designed for the simultaneous reproduction of six slice images b _] to b ₆ , lens regions with six different focal lengths f to f are provided and polarization and color filters are assigned as follows

Δ B C D E F

0 ^° red 0 ^° red 90 ^° red 90 ^° red

0 ^° green 0 ^° green 90 ^° green 90 ^° green

0 ^° blue 0 ^° blue 90 ^° blue 90 ^° blue where column A shows the layer images or parts of the layer images that are simultaneously displayed side by side in the object plane, column B the polarizations of polarization filters that are assigned to the layer images or parts of the layer images that are shown, in column C the spectral property of color filters, which are also assigned to the reproduced slice images or parts of the slice images, in column D the lens areas assigned to focal lengths, in column E the polarization direction of polarization filters assigned to the lens areas and in column F the spectral property of Color filters, which are also assigned to the lens areas

I 0 arrangement according to one of claims 6 to 9, wherein the filters associated with the slice images b _χ (x = ln) or their parts are arranged directly on or at least near the object plane and the filters associated with the lens regions are arranged on or at least near the surface of the lens regions

I I arrangement according to one of claims 6 to 9, wherein the coloring and / or polarization filter layers associated with the lens regions directly in the

Aperture plane of the imaging device are arranged

1 2 Arrangement according to one of claims 6 to 9, in which instead of the color filters, which are assigned to the layer images b _χ (x = ln) or parts thereof, an image generator (1) with color representation, preferably a color monitor, is provided

1 3 arrangement according to claim 5, characterized in that the image generator (1) for the cyclic reproduction of the layer images b _χ (x = ln) and / or parts thereof is designed and as a means for the temporal assignment of lens areas of a certain focal length f _χ ( x = ln) a controllable shutter (3) is provided for each slice image or parts thereof, as well as a synchronous control, which is connected to both the imager (1) and the shutter (3), whereby - The imager (1) is controlled during a period of time t _ι so that the layer image b _t or parts b _π , b _{i 2} b _{] m} are reproduced thereof and the shutter (3) is controlled so that a only lens areas of focal length f are available, the imager (1) is activated for a period t ₂ such that the slice image b ₂ or parts b, bb thereof are reproduced and the shutter (3) is activated in this way t is that only lens areas of focal length f are available for generating an image a ₂ and so on Arrangement according to claim 1 3, wherein the shutter (3) are arranged at least approximately in the aperture plane of the imaging device

Arrangement according to one of the preceding claims, characterized in that the lens regions are formed on a multifocal Fresnel lens (2)

Arrangement according to claims 1-5, characterized in that a multifocal Fresnel lens (2) is provided with lens areas which are four different

Have focal lengths f to f ₄ and which are preferably square, particularly preferably circular, very particularly preferably strip-shaped

Arrangement according to claims 1-5, characterized in that a multifocal Fresnel cylinder lens is provided with stripe-shaped lens areas which have four different focal lengths f to f

Arrangement according to one of Claims 1 5 to 1 7, characterized in that a shutter (3) is provided, in which the transparency for the imaging beam path is influenced in individual cross-sectional areas p (x = 1 n), one cross-sectional area in each case Is assigned to the lens area, the transparency for each cross-sectional area can be switched from a minimum to a maximum and the switching is carried out as a function of the synchronous control

Arrangement according to Claims 1 8, characterized in that a flux module installation placed in the imaging beam path is provided as the shutter (3), in which, when a liquid region area corresponding to one of the cross-sectional areas in the imaging beam path is actuated, the polarization direction changes for this cross-sectional area is achieved and, in cooperation with a polarizer arranged in the imaging beam path with a fixed polarization direction and a downstream analyzer, also with a fixed polarization direction, a change in the transparency is effected for the cross-sectional area in question, the transparency being preferred in the activated state and the maximum in the non-activated state Minimum (black mode) or particularly preferably in the activated state the transparency has the minimum and in the non-activated state the maximum (white mo de)

Arrangement according to Claims 1 5, characterized in that a monofocal Fresnel lens (6) of focal length f is arranged at a distance f in front of the multifocal Fresnel lens (2) for the purpose of scale correction in the viewing direction of the viewer (4) / the camera

Arrangement according to Claims 6 to 20, in which the imager (1) for the simultaneous reproduction of a part number n of the slice images b _χ (x = ln) or parts thereof during a time period t. , for the simultaneous reproduction of a partial number _{2 of} the slice images b _χ (x = ln) or parts thereof during a subsequent time period t and so on, and for the cyclical repetition of these time periods and both

Means for spatially assigning lens areas of a certain focal length to one of the slice images or parts thereof during a time period t, as described in claims 6 to 1 2, as well as means for temporally assigning lens areas to further focal lengths to cyclically successive slice images or parts thereof , as described in claims 1 to 20, are present, a focal length being assigned to each slice image or, conversely, a slice image being assigned to each focal length

Arrangement according to Claim 21, in which the imager (1) for reproducing a partial number consisting of two slice images b,, b ₂ or parts b, bb, b, bb thereof during a time period t and for displaying a partial number consisting of two slice images b, b or parts bbb, b, bb of which are formed during a time period t, four lens regions of different focal lengths f to f are provided and polarization filters are assigned as follows

Time period ABCD tb 0 ^° f 0 ^{° b} _ 90 ^° f 90 ^°

0 ^° f 0 ^°

90 ^° 90 ^° Column A shows the slice images or parts of the slice images which are simultaneously displayed side by side in the object plane, column B the polarizations of polarization filters which are assigned to the slice images or parts of the slice images reproduced, column C the focal lengths of the assigned lens areas and column D the polarization direction of polarization filters that are assigned to the lens areas

Arrangement according to one of claims 1 3 and 21, characterized in that the control is provided with a clock frequency f _Takι which is above the multiple of the Fhmmer merger frequency V _{AU e of} the eye and which is preferably f> v * n / l, with n the total number of slices and I is the number of each time period t _χ simultaneously reproduced slices

Arrangement according to one of the preceding claims, characterized in that the object plane on which the slice images are displayed spans the plane X, Y and the optical axis (5) is aligned in the Z coordinate

Arrangement according to one of the preceding claims, characterized in that two-dimensional and / or three-dimensional or autostereoscopic images are provided as layer images

Arrangement according to one of the preceding claims, characterized in that the slice images b _χ (x = ln) are stretched or compressed in at least one of the coordinates X, Y.

Arrangement according to one of the preceding claims, characterized in that one of the focal lengths is f = ∞

Arrangement according to one of the preceding claims, characterized in that the slice images b _χ (x = ln) are shown in the object plane in a self-illuminating manner Arrangement according to one of the preceding claims, characterized in that the layer images b _χ (x = ln) are shown in the object plane in an optically reflecting or remitting manner

Arrangement according to one of the preceding claims, characterized in that the areal extent of the individual lens regions and their distances from one another, as well as the areal extent of the individual slice images or reproduced parts thereof and their distances from one another - measured in at least one of the coordinates X, Y - in relation to the distance to a viewer (4) and / or a camera are designed so that the catch is not disruptively visible

Arrangement according to claims 6, 7, 9, 11, 21 or 22, in which the polarization filters are preferably designed as circular polarization filters with right and left rotating polarization directions, but particularly preferably as linear polarization filters

Arrangement according to claim 1 5 with a multifocal Fresnel lens with a plurality of optical active surfaces (W _n ), which are assigned to at least four different categories (n) with respect to their focal length, each of which

Effective surfaces (W) of a category have the same focal length (f _n ), at least one category with a positive focal length and at least one category with a negative focal length is provided, adjacent active surfaces (W) with their respective borders always adjoin each other directly and the Fresnel lens (2) is designed as a flat plate or film with a substantially constant thickness

Arrangement according to claim 32, characterized in that the active surfaces (W) are arranged alternately in a randomly generated sequence

Arrangement according to claim 32, characterized in that the active surfaces (W) are arranged in defined sequences, each sequence comprising exactly one active surface (W) from each category (s)

Arrangement according to claim 34, characterized in that the order of the active surfaces (W) is the same in all sequences Arrangement according to one of Claims 32 to 35, characterized in that active surfaces (W _n ) from categories (n) with a positive focal length and active surfaces (W) from categories (n) with a negative focal length alternate in succession

Arrangement according to one of claims 32 to 35, characterized in that within a sequence of at least four different categories (n) two active surfaces (W) with a positive focal length always follow two active surfaces (W) with a negative focal length or vice versa

Arrangement according to one of Claims 32 to 37, characterized in that the number of categories (n) with a positive focal length is equal to the number of categories (n) with a negative focal length

Arrangement according to one of claims 32 to 38, characterized in that the active surfaces (W _n ) are designed as strips inclined to the main plane of extension of the Fresnel lens (2), the sum of the widths d _{n of} all active surfaces (W. Projected onto a normal of the main plane of extension) ) with a positive focal length essentially equal to the sum of the widths d _{n of} all effective areas projected onto the normal with a negative focal length

Arrangement according to Claim 39, characterized in that the strips of the sequence which are at a distance of 1 50 mm from the optical axis are dimensioned in accordance with the following regulation

n α d h

1 33, 4621 ^' 0.0226 mm 0.0342 mm

2 -9.401 9 ^' -0.0089mm 0.0540mm

3 1 5, 2659 ^° 0.01 1 9 mm 0.0435 mm

4 -23, 0060 ^° -0.0255 mm 0.0601 mm

with n the numerical index of the category, α _n the effective flank angle between the relevant effective surface (W) and the main extension plane, d the width of the relevant projected onto the normal to the main extension plane

Effective area (W) and h _{n of} the width of the relevant effective area (W) projected onto the main extension plane Arrangement according to one of Claims 32 to 38, characterized in that the active surfaces (W _n ) are designed as strips inclined to the main extension plane of the Fresnel lens (2), the projection of the width h _{n of} the active surfaces onto the main extension plane being the same for all categories or an integer multiple or a rational fraction of a reference quantity

Arrangement according to Claim 41, characterized in that the strips of the sequence which are at a distance of 1 50 mm from the optical axis are designed in accordance with the following regulation

n α d h

1 33, 4621 ^° 0.0330 mm 0.0500 mm

2 - 9.401 9 ^° -0.0083 mm 0.0500 mm

3 1 5, 2659 ^° 0.01 36 mm 0.0500 mm

4 - 23.0060 ^° -0.021 2mm 0.0500mm

with n the number index of the category, α _n the effective flank angle between the relevant active surface (W) and the main extension plane, d the on the

Normal width of the relevant effective area (W) projected to the main extension plane and h _{n of} the width of the relevant effective area (W) projected onto the main extension plane

Arrangement according to claim 41, characterized in that the strips of the sequence, which is at a distance of 1 50 mm from the optical axis, are designed accordingly to the following regulation

n α d h

1 33, 4621 ^° 0.0330 mm 0.0500 mm

2 -9.401 9 ^° -0.0083mm 0.0500mm

3 1 5, 2659 ^° 0.01 36 mm 0.0500 mm

4 -23.0060 ^° -0.0425mm 0.1000mm

with n the number mdex of the category, α _n the effective flank angle between the relevant effective surface (W) and the main extension plane, d that on the

Normal to the width of the relevant projected onto the main extension plane effective area (W) and h the width of the relevant effective area (W) projected onto the main extension plane

Arrangement according to claim 41, characterized in that the strips of the sequence, which is at a distance of 1 50 mm from the optical axis, are designed according to the following regulation

n α d h

1 33, 4621 ^° 0.0330 mm 0.0500 mm

2 -9.401 9 ^° -0.0248 mm 0.1500 mm

3 1 5, 2659 '0.01 36 mm 0.0500 mm

4 -23, 0060 ^° -0.021 2 mm 0.0500 mm

with n the number mdex of the category, α _n the effective flank angle between the relevant effective surface (W) and the main extension plane, d that on the

Normal width of the effective area (W _n ) projected to the main extension plane and h the width of the relevant effective area (W _n ) projected onto the main extension plane

Arrangement according to Claim 41, characterized in that the strips of the sequence which are at a distance of 1 50 mm from the optical axis are dimensioned in accordance with the following regulation

n α d h

1 29.5063 ^° 0.02830 mm 0.05 mm

2 1 2, 1 576 ^° 0.021 54 mm 0.10 mm

3 -1 0.8855 ^° 0.00962 mm 0.05 mm

4 -24.521 1 ^° -0.02281 mm 0.05 mm

with n the numerical index of the category, α _n the effective flank angle between the relevant effective surface (W _n ) and the main extension plane, d the width of the relevant active surface (W) projected onto the normal to the main extension plane and h _n the width of the relevant active surface projected onto the main extension plane (W) Arrangement according to one of Claims 32 to 45, characterized in that the Fresnel lens (2) is a cylinder nut with active surfaces (W) running parallel to one another

Arrangement according to one of claims 32 to 46, characterized in that the width of the active surfaces (W) is smaller than the visual resolution of the human eye

Arrangement according to one of Claims 32 to 47, characterized in that the surface (2d) opposite the active surfaces (W _n ) on the Fresnel lens (2) is a highly precise, flat surface

Arrangement according to one of Claims 32 to 47, characterized in that the surface (2d) opposite the active surfaces (W _n ) on the Fresnel lens (2) is a curved surface

Arrangement according to claim 1 5 with a multifocal Fresnel lens with a plurality of curved optical active surfaces W which have at least four different focal lengths f (n = 1> 4), characterized in that the total surface of the Fresnel lens (1) is in one Number of strip-shaped sectors S is structured, with m a continuous number from this number, sections of active areas having the same focal length f within each sector S and sections of active areas W of different focal lengths f being present within adjacent sectors S

Arrangement according to claim 50, characterized in that the Wirkfla chen W _{n are} arranged in a ring

Arrangement according to claim 50 or 51, characterized in that the sectors S are aligned in a straight line and parallel to one another

Arrangement according to one of claims 50 to 52, formed as a flat plate or film with a substantially constant thickness 54 Arrangement according to one of claims 50 to 53, characterized in that the active surfaces W within a sector S while avoiding

Always directly adjoin the sides of the store

55 Arrangement, according to one of claims 50 to 54, characterized in that the widths of the effective surfaces W are smaller than the visual resolution of the human eye

56 A method for producing a multifocal Fresnel lens, designed according to one of claims 50 to 55, characterized by the following method steps

Production of a blank for the later Fresnel lens (1) with a plastically deformable surface,

Production of several press punches P _n , which are suitable for plastic deformation of the surface, each press punch P _n having the negative structure of annularly arranged active surfaces W _{n of} one of the focal lengths f, separating the press punches P _n into stamp strips, the stamp strips in shape and dimension in each case correspond to the sectors S on the Fressellellse (1) to be produced, - stringing together individual stamp strips to form a combined press stamp P _n ^' , in which the negative structure of active surfaces W _{n of the} same focal length f is present within each stamp strip and adjoining stamp strips with active surfaces W different Focal lengths f are provided, and finally - deformation of the surface of the blank by placing the combined press ram? _ / And acting on the surface under pressure until the structures of the active surfaces W are plastically embossed into the surface

57 The method according to claim 56, characterized in that copper is provided as the material for the press ram and the structuring of the press ram P is carried out with a Einkπstall diamond cutting tool

58 A method according to claim 56 or 57, characterized in that a polymer material, preferably PMMA, is provided as the material for the Fresnel lens (1) and the structuring is carried out by hot working

9. A method for producing a multifocal Fresnel lens, designed according to one of claims 50 to 55, characterized in that first a casting or injection mold is produced which has the negative contours of the lens and then the mold is poured out with a thermal plastic material or is sprayed out, the plastic material assuming the contour of the lens.