WO2009138741A2

WO2009138741A2 - Display apparatus

Info

Publication number: WO2009138741A2
Application number: PCT/GB2009/001197
Authority: WO
Inventors: Paul Andrew; Simon Humphreys
Original assignee: Activ8-3D Limited
Priority date: 2008-05-13
Filing date: 2009-05-13
Publication date: 2009-11-19
Also published as: WO2009138741A3

Abstract

A display apparatus including means for producing a primary image, means for producing a secondary image, and an inclined partially reflective screen interposed in the optical path of the secondary display in such manner that light from the means for producing the secondary image display and reflected by the screen is superimposed along the optical path for the primary image so as to produce a composite three dimensional virtual display optically located to the optical rear of the primary image as seen by a viewer.

Description

DISPLAY APPARATUS

This invention relates to display apparatus.

Many forms of display apparatus are known.

One such display apparatus involving the combined effects of light transmission and reflection is commonly known as 'Pepper's ghost'.

One of the problems in relation to the known traditional Pepper's ghost apparatus is that it inherently involves apparatus occupying considerable space in relation to the observed viewable size of the images being presented/produced by the apparatus.

It is an object of the present invention to provide a Pepper's ghost type/form of display apparatus that is less demanding on space as compared with known apparatus providing similarly sized images to the viewer.

Broadly according to a first aspect of the invention there is provided a display apparatus in which a primary image and a virtual secondary image are required to interact, wherein in operation the plane of the primary image is effectively located along the viewing direction of the virtual secondary image plane in advance of the virtual image plane.

A further aspect of the invention provides a display apparatus in which a primary image and a secondary reflected image are transmitted onto a projection screen by the use of projector(s) and/ or LCD(s)/plasma(s), thus creating a primary image on the projection screen and a secondary reflected image behind the primary image. In accordance with a second aspect of the invention there is prvided a display apparatus including means for displaying a primary image/object, means for displaying a secondary image/object, an inclined partially reflective screen interposed in the optical path of the secondary image/object of the display in such manner that light reflected by the screen is superimposed along the optical path for the primary display so as to produce a composite three dimensional virtual display optically located to the optical rear of the primary display.

Preferably the primary display is produced by a image display means arranged to produce a image in a plane transverse to a viewing axis of the apparatus, and the primary display plane.

For a better understanding of the invention and to show how to carry the same physical reference will now be made to the accompanying drawings in which;-

Figure 1 very schematically illustrates the principles of known arrangement for Pepper's ghost apparatus,

Figure 2 schematically illustrates in a similar manner a first embodiment arrangement for Pepper's ghost apparatus incorporating the concepts of the present invention and

Figure 3 schematically illustrates in a similar manner a further embodiment arrangement for Pepper's ghost apparatus incorporating the concepts of the present invention.

Referring now to Figure 1 the apparatus shown therein includes a housing 1 that is schematically represented by a horizontal section 2 and a vertical section 3 that is beneath the horizontal section 2.

The horizontal section 2 has a rear end wall 4, a base 5, side walls 6 a top 7 and a front wall 8. This front wall 8 is formed by a transparent viewing window. The vertical section is connected to the base 5 as indicated in the Figure. The vertical section includes a base 9 and upstanding walls 10 whose upper edges connect with the base 6 of the horizontal section 2. As so far discussed the assembly of 20 the two sections 2 and 3 effectively forms as hollow L shaped housing..

A partially reflective screen 11 that is inclined at an angle of approximately 45 degrees to the vertical is provided at the region of the intersection of the two sections 2 and 3.

The relative dimensions of the two sections 2 and 3 and the screen 11 are such that a horizontal central plane 12 extending lengthways of the horizontal section 2 is intersected by the vertical central plane 13 of the vertical section 3 and with the central region 14 of the screen.

With this arrangement the region 14 point of intersection of the aforesaid planes and that of the screen 11 defines the position of the viewing optical axis of the Pepper's ghost apparatus.

Conveniently, if considered appropriate for a particular embodiment of the apparatus the interior of the two sections can be suitably coated/covered with ablack non reflecting coating/covering.

At the base of the vertical section 3 there is located means (not shown) for providing a primary display that it is desired to display/exhibit by use of the apparatus. This primary display image can be a static image or object or a dynamic/moving image or object .

As seen in the Figure 1 a portion of he light of the primary image appearing at the screen 11 is reflected by the screen towards the left hand side of the Figure where it can be viewed by a person appropriately positioned with respect to the aforementioned optical axis. The remainder of such light passes through the screen 11.

As a result of the positioning and the inclination of the screen the display that a viewer sees when looking towards the screen will appear as a virtual display 15 located at a distance behind the screen 11 effectively equal to the distance between the centre of the screen 11 and the position of the primary display source located at the base 9 of the vertical section.

Since it is normally required to view such an image in conjunction with a secondary image whose source 16 is located optically to the rear of the primary virtual image position,

In Figure 1 this secondary image source 16 is located at the right hand end of the horizontal 2 of the housing 1. As a result since this second image is located further to the rear of the screen 11 it significantly increases the overall length of the housing and the complexity of its construction of the apparatus.

In practice, it has been found for many applications of apparatus such as discussed in relation to Figure 1 that the length of the apparatus can introduce inherent disadvantages in some such applications particularly where space for locating apparatus for use and/or transportation of the apparatus, and storage of the apparatus etc. is limited .

It has been found that apparatus incorporating the concepts of the present invention enables a significant reduction in the overall size of the apparatus. Thus it has been found that by significantly varying the optical arrangements of the apparatus as\compared with hitherto known arrangements the overall length of the apparatus can be reduced as is indicated in the embodiment of the apparatus schematically shown in relation to Figure 2 which can be regarded as illustrating a Pepper's ghost apparatus incorporating the concepts" of the The Figure 2 embodiment can be considered as comprising a housing 20 in the form of a single hollow closed container separated into upper and lower sections 21 and 22 by means of an inclined partially reflective screen 23 that is inclined to the horizontal at an angle of 45 degrees.

As shown, the housing upper section 21 includes a rear wall 24 (as represented in the Figure), a top 25, side walls 26, and a front wall 27, whilst the lower section 22 includes a base 28, side walls which are actually continuations of the side walls 26 of the upper section, a rear wall that is a continuation of the upper section rear wall 24, and a front wall that is a continuation of the front wall 27. The portion of the front wall 27 associated with the upper section 21 is formed by a transparent viewing screen.

With this arrangement the primary display image 29 is located at the rear wall 24 of the upper section 2.

It will be appreciated that the front to rear dimensions of the housing 20 are selected such that the wall 24 is located at the appropriate optical distance from the screen 23 that enables a viewer located at the intended viewing position 30 to observe the primary display image 29 by looking directly though the transparent region of the front wall 27 into the interior of the housing 20.

This primary display image is producible by directing the output from a LCD/Plasma apparatus 31 located at the base 28 of the housing

The secondary display image which is to be associated with the primary display image can be produced either by means of a display means source 32, such as, for example, a media player such as a laptop or note book, or a dynamic image producing means located in the vicinity of the top 25 of the upper section 21 of the housing and in such position that its display may be seen by the viewer following reflection by the inclined screen 23.

The production of the primary display image involves the provision of a projector 33 located near the top of the upper section 21 which projector is arranged to project an image serving as the primary image direct onto the rear wall 24 of the housing The production of this image is very schematically represented by diverging lines 34.

The first mentioned mode of producing the secondary image, by reason of it being reflected by the screen 23, takes the form of a virtual display that is located in a plane that is displaced along the optical axis of the viewing direction relative to the plane of the primary image. As a consequence the viewer observes a three dimensional representation of the combined primary and secondary images located to the rear of the plane of the virtual display .

The secondary image by reason of its association with the screen 23 inclined at 45 degrees to the horizontal will appear to the viewer at the viewing position 30 as though it is located at the back of the apparatus and will in practice be optically positioned behind the primary image 29. That is to say the virtual image of the apparatus is located in a plane parallel to the plane of the rear wall 24 of the apparatus.

Referring now to the embodiment illustrated in Figure 3, as in the case of the Figure 2 embodiment, the Figure 3 embodiment comprises a housing 20, with a top 25, a bottom 28, a rear wall 24, and a front wall 22.provided with a transparent viewing region.

In the Figure 3 embodiment the positions of the LCD /plasmas 32 and the units 32/33 are effectively interchanged. Thus, as may be noted from Figure 3 the output from the media player unit 32 is reflected by the inclined screen 23 towards the rear wall of the housing whilst the output from the unit 31 at the top of die housing is likewise reflected by the screen in such manner that as seen by a viewer at 30 a secondary image is produced at a plane located to the rear of die primary image plane.. The distance, as in die case of die Figure 2 embodiment, between die primary and secondary images can be regarded as the virtual image depth.

Whilst in relation to die above discussed embodiments of Figures 2 and 3 die inclination of die screen has been stated to be 45 degrees die angle of inclination can be otiier than 45 degrees and be witiiin an angular range of 45 tio 90 degrees.

Witii a view to providing die facility, where required, of illuminating die interior of die housing lights 36 are provided in die interior of the housings

24.

It will be appreciated that die distance separation between die primary and secondary images produces as seen by die viewer a tiiree dimensional image.

As is indicated in Figure 3 die over all lengdi of die housing is reduced as compared witii die embodiment shown in Figure 2. In addition die sense of die inclination of die screen 23 illustrated in Figure 3 is reversed as compared with die inclination of the screen of die Figure 2 embodiment.

As is shown in Figure 3 an LCD/plasma arrangement 24 can be positioned behind the position of die primary image plane so as to provide die source of the primary image. In general the apparatus above discussed is one in which a primary image and a secondary reflected image are transmitted onto a projection screen by the use of projectors) and/or LCD(s)/plasma(s), thus creating a primary image on the projection screen and a secondary reflected image behind the primary image.

Thus from he forgoing it will be noted that the concepts of the invention provides display apparatus including means for displaying a primary image, means for displaying a secondary image which appears to be created in virtual space behind the apparatus, and the use of a partially reflective screen which can be inclined at a desired angle such as 45 degrees, to create a secondary front image which appears to be in three dimensions, and a secondary video background which creates virtual depth behind the primary image. The light reflected by the screen is superimposed in the optical path for the primary display so as to produce a composite three dimensional virtual display optically located to the optical rear of the primary display.

In practice it has been found that since the partial reflectivity of partially reflective materials typically have a reflectance value of some 12% and a transmission value of 84% the brightness of what (in the Figure 1 arrangement) is considered to be the virtual image is increased by a factor of 7 since the images directly associated with the inclination of the screen are in practical terms reversed so that the brightness of the secondary image is correspondingly reduced by a factor of 7.

As may be noted from the Figures 2 and 3 the virtual display is located to the rear and effectively behind the physical rear of the actual apparatus. The distance between the primary and secondary images can conveniently be regarded \as defining a victual image depth for the images involved..

Thus as a result of the proposals of the present invention the physical depth of the housing for the apparatus can be more than halved as compared witih known apparatus thereby resulting in a compact installation presenting a relatively bright primary display without undesirable compromising of the perceived 'Pepper's ghost 3 dimensional effect

From the above it will be noted that a Pepper's ghost apparatus incorporating a single in-line housing construction greatly facilitates the construction of such apparatus in so far as the size and tihe visual shape of the housing are concerned

In the above discussion related to the display apparatus reference is made to the use of a display screen 11. As will be appreciated the screen needs to be mounted in a uniform tensioned condition and in particular in the case where the screen comprises a thin film plastics the mounting has to be such as to form a uniformly stretched sheet, which for various reasons it is required to be able to support in an upright, horizontal or inclined position large sheets of thin film plastics material.

It is convenient to note that in relation to display apparatus involving such sheets the sheets can have a surface area of several tens of square metres with width and height dimensions extending over tens of metres.

It is known to support such thin film sheeting by attaching at pre-selected spaced positions along the edge regions of the thin film material tensioning wires, straps or the like that connect with the edge regionsof the material by way of a frame arrangement which involves piercing the edge regions to receive connection pins or the like.

Thus when a thin film sheet is mounted under tension in such manner there is always the inherent risk that the piercing of the sheet edges so damages the sheet that the formation of the holes initiates the spreading of fracture/stress lines into the body of the thin film material as the tensioning straps are tightened to tension the sheet sufficiently to avoid the development of and/or the removal of any creases or ripples that may be present in the stretched thin film sheet. The presence of such fracture/stress lines can lead to the development of splits or similar damage that results in irreparable damage or at least a reduction in the optical characteristics/phenomena of the stretched sheet.

It is an object of the present invention to avoid the need to pierce sheet material for the purposes of mounting the sheet in a stretched condition. Broadly according to a first aspect of the invention there is provided sheet gripping/ clamping unit for securing the edge region of sheet material to a support frame by a clamping action that does not involve piercing the sheet material..

In a preferred construction the clamping unit incorporates an anvil part, shaped as to be engageable with an edge region of sheet material, means for selectively exerting pressure upon the edge region when engaged with the anvil, and means for preventing relative displacement between the surfaces of the sheet and the damp

in a further preferred construction the clamping unit includes an anvil plate, and a pressure producing means mounted to the anvil plate in such manner as to define a recess for receiving the edge region of the sheet material after said edge region has been folded over to provide a U formation, an elongate element for engaging in the base of the U, and a layer of high friction material for shrouding the U formation, the arrangement being such on displacing the pressure means towards the anvil plate the high friction layer is compressed against the U formation in the sheet edge and additionally traps the elongate element whereby the latter assists in the retention of the sheet edge in the clamp.

For a better understanding of the invention and to show how to carry the same into effect reference will now be made to Figure 4 of the accompanying drawings which is a schematic side view of a clamping device of the invention the clamp unit 1 shown therein includes an anvil/ clamp body 2 having a base or anvil plate 3 which can be of rectangular form.

A guide bracket/frame 4 that projects from the base plate 3 receives and locates a positionally adjustable clamping plate.

The clamping plate 5 has a main body 6 which bears against the face surface 7 of the base plate 3 and which is shaped as to provide an inclined wedging surface 8 which co-operates with a complementary surface provided on the inside of the bracket 4. The plate 5 provides a surface 10 that faces towards the face 7 to define a recessl 1 for receiving the edge region 12 of a thin film sheet 13.

As will be seen from the Figure the edge region 12 is turned to overlay the sheet 13 to form what may be regarded as a U shaped trough 14 into the bottom of which is provided an elongate pin or rod 15 so that the latter rests in the bottom of the Utrough and in so doing provides a uniform stiffness to the bottom of the trough.

A high friction non-slip packing 16 i.e., strip material covered with a surface formed by a coating of a fine grit is deformed to a U shape and is introduced into the recess such that the sheet edge 12 is located between the adjacent uprights of the recess 11. To produce a sheet edge clamping action the wedge plate is displaced (as seen in the Figure) downwards by pulling upon a strap (not shown) connected with a S shaped member 17 conveniently regarded as a S hook that engages with the lower end region of the clamping plate 6 so that a thicker part of the wedge is pulled towards the bracket 4 and in so doing forces the clamping plate 5 into closer and firmer engagement with the anvil plate 3.

In use the edge region of the sheet material is folded over to produce the U shaped trough 14 and the pin or rod 15 is dropped into the trough. If found more convenient the pin or rod 15 can be laid upon the thin film sheet marginal edge region 12 and the edge folded over using the pin or rod as a folding guide.

The high friction material 16 is engaged over the folded thin film edge region 12 and the sandwich comprising the edge region of the sheet 13, the wedge 14 and the high friction material 16 and the the sheet wedge 14. The clamping unit is then engaged with the folded overlapping region of the sheet 13 and the S hook 17is given an initial pull to produce an initial tightening sufficient to retain the clamping unit in a required position.

A series of the clamping units is distributed around the periphery of the thin film sheet 13 and the associated\clamping straps are\ coupled to a structure/frame (not shown) of a size appropriate to the\ size of the thin film sheet to be supported.

The straps are then tightened in a sequence that ensures an even distribution of the stretching forces applied to the sheet 13.. It will be noted that the provision of the high friction material prevents any relative movement between the clamping arrangements and the material of the sheet so that possible damage to Ihe sheet is avoided.

Claims

1. A display apparatus, including means for producing a primary image and means for producing a secondary reflected image are arranged to transmit said images onto a projection screen in such manner as to create a primary image on the projection screen and a secondary reflected image at a location behind the primary image.

2. A display apparatus as claimed in claim 1, wherein said images are arranged to be transmitted by means of projector(s) and /or LCD(s)

3. A display apparatus as claimed in claim 1 or 2, wherein the primary display image is arranged to be produced by an image display means arranged to produce an image in a plane transverse to a viewing axis of the apparatus, and the primary image plane.

4. A display apparatus as claimed in claim 1,2 or 3,and wherein the secondary display which is\ to be associated with the primary display is arranged to be produced by means of a computerized display/or standard lights sources located in the vicinity of the top or bottom of the housing of the apparatus and in such position that the display thereof may be reflected by a partially reflective inclined screen and interacting with the field of view of the primary display as seen by a viewer..

5. A display apparatus as claimed in claim 4, and wherein the second display which is to be associated with the primary display is arranged to be produced by means of a laptop, notebook or a dynamic image/object located in the vicinity of the base or top of the housing of the apparatus in such position that its display may be seen reflected by the partially reflective inclined screen to interact with the field of view of the primary display as seen by a viewer.

6. Apparatus as claimed in claim 5, and wherein the housing of the apparatus is in the form of a single hollow closed container separated into upper and lower sections by means of an inclined partially reflective screen that is inclined to the horizontal.

7 Apparatus as claimed in claim 6, and wherein the partially reflective screen is inclined at an angle of between 45 and 90 degrees.

8. Apparatus as claimed in any one of the preceding claims, wherein the housing of the includes an upper section including a rear wall, a top, side walls, and a front wall,and a lower section including a base, side walls formed by continuations of the side walls of the upper section, a rear wall that is a continuation of the rear wall of the upper, and a front wall that is a continuation of the front wall of which a portion that associated with the upper section is formed by a transparent viewing screen.

9. A sheet gripping/ clamping unit for securing the edge regions of sheet material to a support frame by a clamping action that does not involve piercing the sheet material..

10. A sheet griping/ clamping unit as claimed in claim 9, and wherein the clamping unit incorporates an anvil part, shaped as to be engageable with an edge region of sheet material, means for selectively exerting pressure upon the edge region when engaged with the anvil, and means for preventing relative displacement between the surfaces of the sheet and clamp

11. A sheet griping/ clamping unit as claimed in claim 9, and including an anvil plate, and a pressure producing means mounted to the anvil plate in such manner as to define a recess for receiving the edge region of the sheet material after said edge region has been folded over to provide a U formation, an elongate element for engaging in the base of the U, and a layer of high friction material for shrouding the U formation, the arrangement being such on displacing the pressure means towards the anvil plate the high friction layer is compressed against the U formation in the sheet edge and additionally traps the elongate element whereby the latter assists in the retention of the sheet edge in the clamp.

12. A sheet griping/ clamping unit as claimed in claim 10 or 11, and wherein the clamping plate has a main body which bears against the face surface of the base plate and which is shaped as to provide an inclined wedging surface which co-operates with a complementary surface provided on the inside of the bracket

13. A sheet gripping/ clamping unit as claimed in claim 12, and wherein the plate provides a surface that faces towards the face to define a recess for receiving the edge region of a thin film sheet .