WO2004102064A1

WO2004102064A1 - Light source

Info

Publication number: WO2004102064A1
Application number: PCT/CH2004/000263
Authority: WO
Inventors: Gerhard Staufert
Original assignee: Lucea Ag
Priority date: 2003-05-15
Filing date: 2004-04-30
Publication date: 2004-11-25
Also published as: EP1623153A1

Abstract

The invention relates to a light source comprising a plurality of light-generating elements (6) and a support (5) that carries said elements, in addition to a surface-defining pressure-resistant base element (1), which in supporting zones is mechanically connected to the support in such a way that pressure on the surface is diverted by the base element to the support. According to the invention, the support and base element form a plate-shaped unit and the supporting zones are essentially distributed over the entire surface of the light source. The base element can be plate-shaped and have a plurality of cavities (2) that penetrate said element, the cavities being arranged to coincide with the arrangement of the light-generating elements. The light source is extremely flat and intrinsically pressure-resistant, so that it can be mounted on designated surfaces, such as carriageways, runways and taxiways of airfields, footpaths, or corridors and walls of buildings, without for example being integrated into recesses and without constituting a substantial obstacle for wheels rolling over its surface, or causing a person to stumble and sustain an injury.

Description

LIGHT SOURCE

The present invention relates to a light source.

Light sources are available in a wide variety of designs and for a variety of applications.

Light sources for the marking of traffic routes, such as, for example, car terraces and runways of airfields are described in the documents WO97 / 44615, US6168294 and US 4,907,361. In these three and in all other cases known from practice, the described signal lights are installed in depressions, which must be dug out of the surface of the corresponding traffic route for this purpose. The dimensions of these depressions are in the order of 10 to 20 cm in diameter and 5 to 15 cm deep and are therefore essential and expensive construction measures.

The signal lights always include light sources such as halogen lamps or a plurality of packaged LED lamps whose light is guided by means of corresponding optical elements so that it emerges substantially in the region of the uppermost cm of the signal lights in the radial direction and in a predetermined angular range. It is obvious that for this purpose the signal lights must extend at least as far beyond the surface of the traffic route that the area radially escaping light is not obscured. In general, they protrude at least 0.5 to 1 cm beyond the surface.

Always the light sources and optical elements of the signal lights are to be installed in robust and waterproof housing, which are very expensive because of these high requirements.

Light sources are also used as or for information signs such as escape route markings in buildings. Such signs are now attached without exception to the ceiling or overhead height on the walls of the corresponding building. This is done for reasons of good visibility over long distances. Examples of corresponding signs can be found in practice as well as in the specialist and patent literature almost in unlimited numbers. As an example, the document US 5,988,825 called.

The undeniably correct objective of good visibility is no longer met in the event of a fire when the escape route marker is placed on the ceiling or high on the walls, because the smoke caused by the fire first accumulates there. Correct would therefore be an arrangement of the signs on the floor or deep down on the walls. Such an arrangement can be perceived by those affected in extreme cases, even if after prolonged fire only in the area of the soil breathable air is present. An arrangement on the ground prohibits today because of the high costs associated with it, but for today's, described for example in the cited type very expensive and complex housing and additionally expensive structural measures in the form of appropriate recesses in the ground necessary. An arrangement low on the walls is impossible - without expensive installation of the signs in the walls - the, due to the relatively far protruding signs resulting, injury due to.

Another field of application of light sources is in the field of decorative lighting. In this sense, for example, in recent years, for example, increased applications in private homes or offices, where, for example, from the recessed in the ground lights, white light is emitted as a so-called light curtain substantially in the vertical direction in the room. For this purpose, the corresponding lighting must firstly be provided with relatively expensive "walk-in" cases and secondly they must be installed in existing in the ground, expensive wells.

Decorative or safety technology used light panels with the widest possible light emission are known from the writings EP 1 081 426, DE 42 37 107 and DE 199 17 401. None of these writings shows light panels, which would also be suitable as traffic route markings.

Another field of application of light sources is the use, at least as emergency lighting, but at most as the only lighting in public areas such as pedestrian underpasses, parking garages, etc. Such lights are known to be particularly vulnerable to vandalism and must be with the existing light sources therefore outside the mounted direct reach and / or provided with elaborate impact-resistant covers. At least for reasons of maintenance, but also for design and physiological reasons, it would be desirable to attach these lights at least partially in immediate reach, so for example within the first lower meter of a wall. In some cases even mounting on the floor can be useful. Further applications of light source are of course found in the field of general room lighting and in the field of street lighting. Often, the problem of accommodating the light sources in a way that they are protected, optimized in their effect and arranged visually appealing.

A light panel for general room lighting but with a special one-piece reflector body to produce a directivity and light effects shows the German utility model 201 16 022. Also, the illuminated panel disclosed in this document would not be suitable for traffic route marking.

For all applications described above, different, sometimes complex arrangements must be made to meet the requirements of the light sources, their housings and their installation.

It is a recognition of the invention that it is possible to search for technical measures for light sources which at the same time offer solutions to the specific problems arising there in completely different fields of application.

The invention is thus based on the idea of providing a light source which, in at least some of the cases mentioned above, brings about improvements over the prior art. Preferably, the light source should be suitable for different applications and, for example, be easily attachable at suitable locations. It should preferably be inexpensive to produce and install with little effort. For this purpose, the invention offers a completely new approach. It is a flat, thin (total thickness 1 cm or less), in itself pressure-resistant and preferably robust against impact light source available. The light source should be capable of being designed to be robust against environmental influences in some embodiments. In some embodiments, it should have different user-definable spatial light emission and / or light color distribution in different forms.

Flat, in the context of the invention, the light source is when it can - without installation in any wells - on given surfaces such as car terraces, runways of airfields, sidewalks, corridors and walls of buildings can be applied without them a major obstacle to wheels rolling over them or creating a risk of tripping or a risk of injury. The light source is at most 1 cm or even at most 0.7 cm, 0.5 cm or 0.4 cm thick and flat, so plate-shaped.

Compressive, in the context of the invention, the light source is when the alternating load, which is generated, for example, from rolling over them Pneu of trucks or aircraft, or the high local pressures that arise for example when entering the light source with hochhakigen ladies shoes, at least over the Period of their intended life is able to withstand.

Robust against impact, in the sense of this description, the light source is when it can withstand vandalism violent blows carried out, for example, with bottles or similar objects, can withstand such a few blows without significant loss of luminosity he wears. This means at least that it may fail locally, but continues to emit light over a large area.

Robust here further means that the light source is so gas and water vapor-tight that all components contained in it such as light-generating elements (eg, unpackaged LED chip), electrical connections, optical elements, etc., a high minimum life of, for example 20O00 operating hours respectively.

User-definable spatial light emission and light color distribution here means that the light source according to the invention emits its light in such a way:

- That, for example, from each light-emitting point of the flat light source, the light in the same defined solid angle perpendicular or at a desired mean inclination to the surface of the light source, said defined solid angle depending on the embodiment, for example, between ± 10 ° to ± 80 °;

that, for example, the light emanates from the light-emitting points of the planar light source in different defined solid angles and distributions;

that, for example, the light in one or more desired color (s) is not uniformly radiated across the areal light source, but forms a particular defined pattern, such as a string of letters;

that, for example, the light leaves the light source through the lateral boundaries of the light source and / or through the upper surface substantially in the lateral direction in a defined solid angle; and / or that, for example, the light leaves the light source not only on one of the two-dimensional sides, but also exits from the lateral surfaces of the light source in the same or different light distribution to both flat sides and / or possibly additionally.

According to an approach according to the invention, the flat, pressure-resistant light source with light-generating elements on a carrier contains a pressure-resistant plate-like element (base element ^£ ), by means of which pressure acting on the surface of the light source can be derived. In this case, this element is designed and arranged such that it protects the light-generating elements at a pressure exerted on the surface, by deriving the pressure locally on the carrier in the vicinity of the light-generating elements. So there are provided over the whole area distributed and, for example, at least 50% of the area covering supporting zones in which the pressure is forwarded directly to the carrier. Thus, the property of compressive strength in itself and the flatness can be ensured, the light-generating elements are unhoused electroluminescent elements, ie unhoused LEDs or possibly OLEDs.

According to a preferred embodiment, the diameter of the light-generating elements is so small that at least 10 light-generating elements per cm ^{2 can be} attached. According to a specific embodiment, the base element accordingly has at least 10 light-generating elements per cm ² .

According to a particularly preferred embodiment, the base element is essentially flat with a number of "through-holes" corresponding to the task, which penetrate the element in the direction perpendicular to its large surface. whose axis is substantially perpendicular to the large surface of the plate-like element.

The term "through-hole" is intended to include any type of orifice penetrating the flameproof plate-like member in the indicated direction, often the axis of the orifices will be substantially perpendicular to the large area of the plate-like member, but this does not mean that the orifice Furthermore, it also includes through openings, which take over the function of an optically active element, for example as a diaphragm or as a light guide or as a concave mirror According to simple embodiments, the through holes are simple cylindrical holes, the base element thus a perforated plate. In addition, the term should also include openings filled with material, these filling materials generally being optically transparent materials whose surfaces are at most shaped so that-in the sense of lenses and / or deflecting elements-they are optically effective As a rule, the filling of the through-holes is designed such that the surface of the filling, at least by a few hundredths of a mm, lies below the upper edge of the actual through-hole.

The term "carrier" encompasses any structures which carry the light-emitting elements The carrier does not have to be homogeneous, but may consist of a plurality of, for example at least partially foil-like components.

Due to the presence of such through-holes and depressions, local pressure in the direction of the perpendicular to the large area of the pressure-resistant, plate-like element evidently results in pressure-free zones in the interior of the through-holes and depressions, as long as the area of the local, planar load is greater than the area of opening of the largest Through holes or Wells. Wearing zones are formed where there are no holes or depressions. The base element is designed so that the sum of the load-bearing zones, for example, more than 70%, usually at least 50% of the total area and the load-bearing zones evenly distributed over the entire area are available.

This means that the presence of non-bearing areas, for example, at most doubles the pressure loads acting locally on the material of the plate-like element. Since a variety of plastic materials and all metals withstand such pressures, are available to build the pressure-resistant plate-like base element, from the perspective of compressive strength from almost any number of materials available.

The unhoused electroluminescent elements are each arranged near the central axis of said through-holes on the side of the base element facing away from the pressure effect.

Uncased light-emitting diodes (LED chip) are available on the market and can be purchased inexpensively in a wide variety of shapes and different colors as a mass-produced product at low cost. Recently, it is also possible to resort to corresponding unhoused organic light-emitting diodes (OLED). In the following, when talking about LED chip, this should always include the OLED variant. The dimensions of said LED chip are on the order of about 0.3x0.3x0.3 mm.

The possibly very thin carrier is provided according to a preferred embodiment with the necessary electrical conductive structures to the To be able to contact light-generating elements electrically. In the case of the use of LED chip, the electrical contacting is usually carried out by a so-called diebond, which firstly attaches the chip to the carrier and secondly creates a first electrical contact, and by a so-called wire bond from the upper chip surface to a corresponding Contact point of the support plate leads. In other cases, by means of Diebondes only one attachment of the chip, while the electrical contacting is done with two wire bonds.

Of course, the attachment and contacting of the light-generating elements on the carrier can also be effected by means of other methods which are well known from the field of semiconductor chip mounting, such as, for example, the known flip-chip method. This method has the advantage that no wire bonds are needed, but the chips are contacted and fixed directly by means of so-called solder bumps. This brings in addition to a in many cases increased reliability, the advantage that overall a lower height and width. For the light source according to the invention, a variant of the known glass flip-chip technique is advantageously used. As the carrier, an optically transparent material is used on the optically transparent electrically conductive tracks and bond pads are present, which were prepared for example by means of a structured ITO layer. The LED chip provided, for example, with known stud bumps-in principle short torn off bond wires-are bonded with their light-emitting side to the transparent carrier prepared in this way. The following so-called underfill process. In filling the air gap between the LED chip and the transparent support, it is necessary to carry out a transparent material suitable in its viscosity for this purpose. For this purpose, for example, a corresponding silicone gel is suitable. One or more of the thin contacted with the electrically contacted LED chip thin carrier plates are connected to the side facing away from pressure and in the bearing zones of the base member with the same, for example by means of a gluing, soldering or riveting.

The thin support should be constructed so that it, where it is connected to the supporting zones of the base member, take over the pressures transmitted there and can derive, for example, to the ground below the inventive flat, robust light source. The necessary compressive strength is usually given already in the known printed circuit boards for electronic components, so that in a simple version of the known so-called chip on board (COB) technology can be used.

However, in cases in which the light source according to the invention is equipped with a large number of light-generating elements, for example with 16 or 25 LED chips per cm 2, it is essential that the thin support dissipates heat as well as possible, at least local compressive strength , In these cases, it is advantageous to construct the carrier so that it has a metallic carrier foil or plate which has a thin electrically insulating layer, for example a plastic layer some tens of microns thick, but better a 0.5 to 1 micron thin Silicon oxide or silicon nitride layer or a correspondingly thin, for example by means of sol-gel method applied glass or ceramic layer. On this, possibly locally open insulating layer is a next, structured metallic layer, which - possibly with the inclusion of the lower metallic carrier film - allows the electrical contacting of the LED chip. For both mentioned construction possibility of the thin carrier it is - in the sense of the overall structure of the inventive light source - of great advantage if the stocked with LED chip carrier against the influence of water vapor, aggressive gases and chemicals is protected. This can be done, for example, by applying a so-called passivation layer by means of a plasma process.

The advantages of the light source according to the invention are evident. The light source is so robust in itself that no additional housing is necessary. It is still so flat that they do not exceed a project beyond the surface of a traffic route of, for example, 0.5 to 1 cm. And finally, it contains all the necessary optical elements that produce a light distribution corresponding to the described signal lights. This means that the light source according to the invention can normally be applied directly to the surface of the corresponding traffic route without additional elements and without the excavation of depressions, for example by means of gluing or by screwing.

Also in application examples, in which the light source is not mounted rollable, advantages of the inventive light source are obvious.

For example, when used for escape route marking, the flat and inherently flameproof light source without significant structural measures - even later - be fixed to the ground or deep to the walls without the disadvantages described above occur.

The light emission from the light source with, for example, green light takes place in this case, of course, so that a meaningful sequence of letters and characters is created. Due to the relatively flat view angle, which is relatively large Distances, ie, for example, results from 10 m distance when mounted on the ground signs, it may be useful if the structure in the direction of the long distance long drawn letters and characters has, in addition, if appropriate, for example when viewed from a shorter distance , ie when viewed from a steeper angle by means of suitable optical elements shortened perception. An optical structure suitable for this purpose is, for example, one which corresponds to that of the previously known so-called wobbly images.

When used as a decorative lighting, the here at best circular designed light source, without additional structural measures - possibly even later - be fixed to the floor. In one embodiment, the light source according to the invention may for example be designed so that it emits its light at a desired oblique angle to its surface and rotatably mounted about its vertical axis on the ground, which can be adjusted with some such light sources diverse light distributions.

An attachment inside cabinets or as a discrete room lighting directly to walls, etc. is easily possible without structural measures would have to be taken.

The advantage of the flat and inherently pressure-resistant, robust light source according to the invention is also clearly recognizable for the field of application of lighting in public zones. The light source is constructed so that it can withstand many violent blows with blunt objects, and that when maltreated with pointed striking tools it only fails locally and continues to emit light over a large area. This is important if vandalism has to be feared. In addition, it is so shallow that it can be used without additional structural measures and Without any risk of injury - even at a later date - can be mounted directly on the corresponding walls. Further, it can be designed, for example, in their spatial light emission behavior so that their light emerging from the large surface is radiated, for example, at a shallow angle only in the direction of the ground and thus no glare arises.

It is obvious that much more suitable fields of application can be described for the flat and inherently pressure-resistant light source according to the invention.

Here, however, it should only be pointed out that such a light source also has its justification in the field of general room lighting and even in the field of street lighting. In all cases, it is at least very pleasant, for example, if a light source is not destroyed by accidental drops. In the field of street lighting and the described high vandalism is an advantage, but you can see in more mass street lighting whose luminous bodies were willfully destroyed, for example by stone throwing.

Advantageous embodiments of the invention will become apparent from the features of the dependent claims.

The invention also relates generally to an actively illuminating traffic route marking element, which is configured such that it can be rolled over or walked on as a whole. It has a large number of unhoused electroluminescent elements, for example LEDs or OLEDs, and is pressure-resistant and flat. It is directly on a surface or in a flat milled one Street or track can be introduced, its total thickness is not greater than 1 cm, preferably 5 mm. An optically effective additional element may be formed so that light is emitted in a particularly favorable, selected angle; appropriate options will be discussed below.

At this point, the feature of compressive strength is to be discussed and the maximum pressure to be absorbed by the flat, robust light source quantified. Pressure resistant, in the context of the invention, the light source when the alternating load, which is generated, for example, from rolling over them Pneu of trucks or aircraft, or the high local pressures that arise for example when entering the light source with hochhakigen women's shoes, over the period their intended life is able to withstand.

The pressure generated by trucks and aircraft is comparatively low. Thus, the road traffic regulations also for special vehicles of the construction industry or agriculture stipulates that these vehicles may under no circumstances exercise a pressure of more than 1.5 N / mm ² . This also applies, for example, to tracked vehicles. Normally, however, the pressures are much lower. For example, a semi-trailer usually has 12 wheels. Each wheel has about 16 qdm (= square decimeter) bearing surface on the road. This results in about 192 qdm for the whole tractor. At a total weight of 40 tons this results in an average pressure of 400O00 N / l 920,000 lO ² = approx. 0.21 N / mm ² .

For aircraft, the load is about the same size. For example, each of the 16 main landing gear tires of a fully loaded, ie starting, Boeing 747 has to bear a weight of up to 25 t = 250O00 N. The contact surface of such a barely 50 cm wide main chassis tire is about 180O00 mm ² (= about 3 DinA4 sheets). This results in a pressure of less than 1.5 N / mm ² .

The most extreme stress which is to be taken over by the light source according to the invention and additional measures can be expected from ladies with high-heeled shoes. Assuming a weight of 100 kg and a sales area of about 10x10 mm, a pressure of 10 N / mm ^{2 is} generated in moments in which the entire weight rests on a shoulder, which acts on a local area of only 1 cm in size. The base element should therefore not deform significantly plastically or elastically at an applied pressure of up to 10 N / mm ² . The compressive strength is preferably somewhat higher, for example at least three times or five times this value.

Even larger or other loads usually rarely occur in application-dependent foreseeable special cases. One of these special cases, for example, be driving over the inventive light source with the blade of a snow plow. Although the resulting pressure forces are usually not higher than those mentioned above, but there are also high Scherbzw. Peel forces to be expected. In such cases, the light source according to the invention can be protected by additional measures described below.

Even assuming that the pressure loads occurring exceed the above-mentioned pressures by a multiple, that is, for example, up to five times, the approach according to the invention is readily suitable. In some cases it is desirable that the light-generating elements can emit their light in all directions from the light source according to the invention. The construction according to the invention allows this without further ado:

Of course, for this purpose, the first mentioned construction variant of the thin support can be modified so that glass or a transparent plastic such as PMMA used as a supporting element and a transparent adhesive is used to fasten the light-generating elements (eg LED chips).

In the case of a desired best possible heat dissipation, a further variant of the thin carrier is also possible, which allows the LED chip to radiate its light freely in all directions. For this, nothing else is necessary, as to provide the thin carrier there with holes, where later the LED chip should be. The LED chips then "float" on the two wire bonds with which they are electrically contacted.To achieve this, an auxiliary film is first attached to the underside of the thin carrier.This auxiliary film is used to attach the LED chips This can be done, for example, with an optically transparent silicone gel, which only minimally adheres to the auxiliary foil, and then the LED chip is electrically contacted by wire bonds and fixed in a next step a mechanical stabilization takes place in the area of the LED chip and the nearby edge of the thin support, a thin as possible, the optical requirements sufficient plastic layer, so for example a suitable silicone gel, is applied.After a last step, the auxiliary film can now be removed , Now that the arrangement of the light-generating elements is described relative to the pressure-resistant, plate-like element, can be returned to the already indicated optical function of the through holes and the resulting minimum thickness of this element.

Since the light-generating elements, for example, LED chip, in very dense arrangement, so for example at least 10 or 16 to 25 chip per cm ² , may be present, and since also the proportion of through holes on the total area usually does not exceed 50% should, in preferred embodiments, the largest diameter of the through holes should not exceed a value of 1 to a maximum of 2.5 mm. With regard to this small dimension, an LED chip with a light-emitting surface of, for example, only 0.2 × 0.2 mm no longer behaves as a punctiform light source, but as a planar radiator. Each point of this two-dimensional radiator emits - as a rule - its light almost uniformly within a solid angle of ± 80 °. Since for many applications the light source should be able to emit tightly focused light, for example at a solid angle of only ± 10 °, for many embodiments it makes sense to make the through holes such that they bring about concentration of the light at a solid angle of, for example, ± 20 ° , A further concentration and / or change of the spatial radiation can then be taken over by an additional element described later. But it is also possible to make the through holes so that they make in addition to a concentration of the solid angle to, for example, ± 20 °, a deflection of the light by, for example, 20 ° and so the light emission takes place substantially in an angular range, the central beam one Angles of about 70 ° to the lateral extent of the pressure-resistant, plate-like element.

Since, as stated, the light-generating elements are to be regarded as flat radiators, the tangent of the minimum exit angle of the light from the light-emitting element facing away from the through holes first given by the chip width divided by the height of the through hole. This minimum radiation angle can not be reduced even with the most expensive optical aids. If the through hole is completely or partially filled with an optically transparent material which has a refractive index n> 1, this minimum exit angle is increased in accordance with the laws of optics (it is hereby reminiscent of Snell's law of refraction). From this physical situation, it follows that, for an area of the light-generating element of 0.2 × 0.2 mm and an exit angle of ± 20 ° required as an example, the height of the through hole and thus the thickness of the pressure-resistant, plate-like element, depending on the embodiment to 2 mm.

The above considerations apply to all points at the virtual. Surface of the through hole. All rays arriving there directly, ie without deflection in the interior of the through-hole, come, at an arbitrary point, in a corresponding solid angle around the central ray originating from the center of the light-generating surface. However, since this central beam is increasingly inclined toward the edge of the virtual surface of the through-hole, the total solid angle of the light emerging from the virtual surface of the through-hole is increased by twice the amount of the most inclined central beam. As a result, either the height of the through-hole must be correspondingly increased or the through-hole must be filled with an optically transparent material with refractive index> 1, and this optical material must be shaped in the area of the virtual surface of the through-hole so that the central rays - and with them all other rays according to - be redirected into the vertical. For this purpose, the surface of the optical material must be either as a continuous, advantageously aspährische lens, or as appropriate Fresnel lens may be formed or provided with corresponding diffractive structures.

The previous considerations obviously only apply to rays which lead directly from the surface of the light-generating element to the virtual surface of the through-hole. All the flatter rays interact with the walls of the through-hole, thus forcibly acting as an optical element.

In the simplest case, where the surface of the through-hole is not specular, the through-hole obviously acts as an aperture, which blocks out all rays that do not lead directly to the virtual surface. Thus, of course, would be the desired function, the limitation of the exiting light reaches a defined small solid angle, but at the cost of high light loss, which is the more serious, the smaller the desired exit angle. This is often unacceptable.

The surface of the through hole is therefore usually formed as well as possible mirroring. In order for this specular surface to redirect the rays emerging flatly out of the light-generating element at a significantly narrower solid angle to the virtual surface of the through-hole, they must be in the form of a mirror with a parabolic cross-section. For simplicity, for example, if it has the shape of a truncated cone opening upwards, corresponding losses of light must be accepted.

Of course, it is also possible to make the pressure-resistant, plate-like element about 2 to 4 mm thick, so that without further additional elements a concentration of is ensured from the through holes exiting light to, for example, ± 10 °. Also in this case, the necessary for the concentration of light optical elements can be designed so that at the same time a deflection of the light to, for example, about 20 °.

Furthermore, it is obviously also possible to make the through-holes "multistage." This means, for example, that the spatial profile of the through-hole in an initial region which, for example, ranges from the level of the chip surface to a level of 1 mm above this level, is an optical one Function 1 obeys that then at most at this level or within a small change in the level of a rapid, optically not necessarily functional enlargement of the diameter follows and then above this level zone in a second region of an optical function 2 is sufficient.

Of course, if appropriate, more than two such function levels may be present.

Moreover, it is possible to make the filling of the through holes with optical material so that several layers of optical material with different refractive indices follow each other. In the transitions from one optical material to the other then always refraction of the light takes place. The transitions can therefore, for example, be designed as lens-like and / or deflecting zones in such a way that the overall result is an optimum distribution of light.

Of course, as outlined above, the multi-stage nature of the via holes may be due to a corresponding sequence of layers of optical material be combined with different refractive indices so that a further improvement of the light distribution results.

The said fillings of the through holes with optical material remain substantially stress-free even with a mechanical load of the light source according to the invention. This fact substantially extends the choice of available optical materials. Thus, it is in particular possible to use, for example, also permanently viscous materials, such as certain silicones, which, while permanently retaining a certain defined shape under their own weight, would be deformed with little additional mechanical stress. The advantages of such materials can be manifold: firstly they have good optical properties, secondly they are resistant to very high temperatures (at least 250 ° C), thirdly they are water- or water vapor-proof and fourthly they produce, thanks to their viscosity, Even with mechanical and / or thermal deformation of the inventive light source no mechanical stresses on the light-generating elements and their electrical contacts.

The preparation of the pressure-resistant, plate-like and provided with corresponding through holes base element can be done using plastics by the known injection molding method or by another known or newly developed method and therefore needs no further description. However, it should be noted that in this way in the area of the later possibly reflective through holes, although a sufficiently good surface quality, but no mirror surface can be generated. This has to be done in an additional step, for example by means of galvanic growth of a thin metallic mirror layer. For this to be done in the most efficient way, it may be advantageous if the material is a "metallically filled" and weakly electrically conductive plastic is used. The use of such a plastic has the further advantage that within this material a substantially increased heat conduction takes place, which causes the heat emitted by numerous light-generating elements to be rapidly transported away to the surface of the light source according to the invention.

Another possibility is to produce the pressure-resistant, plate-like element, for example by means of the likewise known aluminum die casting process or another metal casting process. This variant has the advantage of even higher pressure and especially alternating strength, a significantly increased heat dissipation and a surface which is already well reflective and whose efficiency is already sufficient in a large number of cases. If a higher efficiency of the mirror surfaces is required, this can be achieved, for example, by means of galvanically grown - and smoothing - additional metal layers.

The mentioned - optional - filling of the through holes with optically transparent material whose outwardly facing surfaces additionally optically acting, so for example lenticular, can be designed, can be done in different ways.

A first possibility is first to combine the pressure-resistant, plate-like elements, which are provided with empty through-holes, with the thin support carrying the light-generating elements and electrically contacted in the regions of the supporting zones, for example by means of gluing or soldering. Thereafter, the through holes can be filled as high as desired, for example by means of doctoring or by means of multi-local casting with the desired optical material, for example with a suitable silicone gel or with PMMA. In In a next step, the still easily deformable optical material can be brought into the desired optically effective form, for example by means of reshaping or stamping on its surface. In a subsequent curing process, the shape thus produced is then solidified at least to the extent that it can not change under its own weight. Of course, it is also possible to perform this type of filling of the through-holes in a plurality of corresponding steps, in which, for example, at each step different optical materials with, for example, different refractive indices and / or with different shape of the surface are used.

A second possibility is to fill the through-holes of the pressure-resistant, plate-like element before combining it with the thin support carrying the light-generating elements with the desired optical material and to form optically effective the surfaces of this material. This procedure has the advantage that the two elements can be tested completely independently of each other. The procedure for filling can be essentially the same as described above. In addition, however, it is possible to perform the filling and molding process by injection molding, which can be significantly cheaper and faster in large quantities.

However, the second approach has the disadvantage that the combination of the two components mentioned several times, namely first the pressure-resistant, plate-like with now already filled through holes provided element with secondly the light-emitting elements bearing thin carrier is not quite trivial: the light-generating elements and these contacting wire bonds must be able to be guided in their full thickness in the through holes, which means that they must not be filled with optical material on the appropriate side so far, without endangering the LED chip and the sensitive wire bonds can take place. If now the two components are connected to one another in the area of the supporting zones without any further measures, an airspace is created around the optically active elements and their wire bonds. This is not desirable for two reasons. Firstly, so can the wire bonds oscillate freely at the slightest movement of the inventive light source, which usually means a significant reduction in the life of the bond and secondly, a direct coupling of light from LED chip into the air because of the high refractive indices of the chip materials, with respect the optical efficiency extremely bad. The combination of the two components must therefore be done so that there is a replenishment of said airspace. Although initially difficult, various simple solutions to the problem have been found, one of which is described here. The through-holes of the component 1 are in the area where later the light-generating elements and their wire bonds should find space designed so that a much larger not a priori filled volume is present. For the purpose of combining the two components, the light-generating elements and their wire bonds are first surrounded on the thin carrier with a drop of optically active material, which is in its viscosity so that it can be freely deformed at low pressure, but in absence of a external load assumes a substantially spherical surface. The amount of optical material around each photogenerating element is sized so that, when combined with component 1 now, it not only completely fills the optically effective portion of the through-holes but also fills a small amount of excess material "laterally" into the larger unfilled volume In this way, a complete filling of the optical path is ensured, and the air spaces remaining in said additional volume do not interfere with the function of the light source according to the invention. In some applications, it is useful if on the outer side, ie on the side of the light exit from the pressure-resistant, plate-like and provided with corresponding through holes element, an additional element is present, the other optical functions in the sense of generating a desired light and / or light color distribution makes.

As a rule, this additional element must be constructed in such a way that the compressive strength of the overall structure is maintained. For this purpose, the additional element in terms of area at least in the region of a sufficiently large part of the load-bearing zones of the pressure-resistant, plate-like and provided with corresponding through holes base element also having bearing area. This part is sufficiently large if the pressures resulting from a load on the overall structure do not exceed the permissible loads for the load-bearing material in any region of the two elements mentioned. In the spaces between these bearing zones then optical elements may be present that would not directly withstand the pressures discussed. Alternatively, the supporting regions of the additional element can be integrated into or formed by the base element, ie the additional element consist of only a plurality of optically active elements in intermediate spaces.

For applications in which the light source according to the invention is loaded with recurrent pressures of the order of magnitude of 1.5 N / mm ² but not with hard impacts, ie, for example, when installed on runways of airfields, it is possible to construct the additional element completely from corresponding optically transparent material , In some applications of the inventive surface and robust light source, it makes sense to protect the thin carrier and the light-generating elements from both sides.

This can be done in the case of unilaterally and / or radiated from the side surfaces light simply by the fact that on the said pressure-resistant, plate-like and provided with corresponding through holes facing away base of the thin carrier a pressure-resistant thin plate, so for example a 1 mm thick steel - Is applied or aluminum plate.

In the case of light to be radiated on both sides, this can be done by fixing a pressure-resistant, plate-like element provided with corresponding through-holes on both sides of the thin support.

To achieve a high optical efficiency, it makes sense in certain cases if the lower edges of the through holes of the base element, i. the edges of the optically acting surfaces of the base element, in the smallest possible distance, so for example at a distance of 10 to 100 microns, are arranged around the light-emitting surface of the light-generating elements around.

This requirement results in the union of the base member with the light-emitting elements holding the carrier in high demands on the spatial mutual alignment of the two elements. This requirement can be met relatively easily when manufactured in small as well as in very large numbers, if the two elements to be united are provided with auxiliary surfaces, which bring them, with or without additional auxiliary elements, forcibly in the correct relative position. The aforementioned auxiliary surfaces can be designed, for example, simply as additional through holes which are precise in shape and position. If the assembly device required for the union of the two elements is now equipped at the locations corresponding to said auxiliary surfaces, for example with cylindrical auxiliary elements provided with a conically tapering tip in its upper part, the two elements to be united are inserted into the mounting device in FIG usually align with far enough accuracy to each other.

If the described auxiliary holes also or only in the region of the supporting zones of the inventive light source are present, they bring a further functional advantage. They can be used as holes for hard attachment of the inventive light source to the substrate. If, for example, nail-like structures with flat heads are shot in sufficient quantity by means of a corresponding shot apparatus through the auxiliary holes in the pad that press the heads of the nail-like structure on the upper side of the pressure-resistant zones of the inventive light source, resulting in a high thrust and Tensile forces resisting connection between the base and the light source according to the invention.

As discussed above in the discussion of the resulting pressures, the light source according to the invention can be loaded with very high additional forces, such as shearing and / or peeling forces, in cases such as when driving over the blade of a snow plow. However, since this is predictably only at specific installation locations, this and similar cases can be easily remedied. First, it can be stated that, for example, an attachment by means of nails guided by the described auxiliary holes is able to withstand said forces, if the nails in a sufficient number near the edge, and possibly also in reduced density in the interior of the surface, the inventive light source available.

If this is not enough, the following additional measures can be taken.

In cases where the surface of the light source according to the invention does not protrude beyond the surface on which it is mounted, i. in cases where it emits its light exclusively from its upper surface, the light source according to the invention can be mounted in a flat, and thus inexpensive producible, cut in the supporting surface, whereby an action of said additional forces can be excluded.

In cases in which the surface of the light source according to the invention has to protrude beyond the surface on which it is mounted, for example in cases in which it emits its light not only from its top but also or exclusively from its lateral surfaces, the light source according to the invention can For example, be protected by very high loads usually additional buffer elements are protected, which are mounted at a small distance so in the area of the inventive light source, that said shear forces generating objects are passed over the inventive light source away. In the case of said snow plow, for example, this means that the blade is lifted by the additional buffer elements until it no longer touches the light source according to the invention laterally but only from above. So far, the electrical contacting of the inventive surface, robust light source has not been discussed. However, since the contacting point (s) and the corresponding electrical conductors should not be higher than the light source itself, but should preferably be rather shallower, this poses a serious task, but it can be solved relatively easily.

For this purpose, it must first be stated that the light source according to the invention is operated with electrical voltages of less than 48 volts, thanks to the use of said light-generating elements, that is to say, for example, of LEDs or OLEDs. In this case, the legislature requires no external insulation of the electrical conductors, which allows a much simpler structure.

It is further to be noted that the carrier carrying and electrically contacting the photogenerating elements is typically constructed so as to be very thin, i. For example, thinner than 1 mm, often even thinner than 0.5 mm and that secondly on its top and bottom each have large, over its entire width or length reaching metallic surfaces, which are suitable for electrical contact to the outside. By the way, "across the entire width or length" does not mean that the metallic surfaces must be completely covering.

Thanks to the two facts mentioned, it is possible to accomplish the supply of electrical energy by means of a so-called flat conductor. This flat conductor is, for example, at least three-layered in such a way that it consists of two metallic foils which are electrically separated from one another by means of a corresponding layer but mechanically connected to one another. Of course, it makes sense to additionally protect the mentioned metallic foils with a preferably abrasion-resistant and electrically insulating layer, which is the metal protects against corrosive influences. If the metallic foils are made of aluminum, a thin anodizing layer, ie an aluminum oxide layer, is used as protection on all sides, but at least on the outer side. Of course, however, other and / or additional protective layers are possible, such as about 100 micron thick films made of PE or PET possible, for example, are laminated on the outside of the metallic films.

The example of copper or - cost-effective - made of aluminum metallic foils must be selected in their thickness and width so that they can transport the required electrical power. Since the inventive surface, robust light source with increasing number of light-generating elements, i. With increasing demand for electrical power at least in a lateral dimension is getting bigger, and since the mentioned flat conductor may be as wide as the larger lateral dimension of the inventive light source, it poses no problem, the flat conductor with a maximum thickness of about 1 mm build.

The connection between such a or similar flat conductor and the light source according to the invention can take place as follows:

The carrier holding the light-generating elements protrudes at least at one edge of the light source according to the invention so far beyond the pressure-resistant base element that the two metallic surfaces to be contacted from outside are sufficiently free to - depending on the application - an electrical transition with sufficiently small contact resistance and with sufficient to enable greater reliability and service life. The flat conductor is treated at its end in such a way that the electrically insulating and mechanically connecting layer is no longer present to some extent and that the metallic foils are bare on their inner surfaces. The zone prepared in this way must be so deep that the two metallic conductor layers are pushed above and below over the layers to be contacted of the light source according to the invention and can be fixed there by means of soldering or gluing with an electrically conductive adhesive.

In general, it can be assumed that an electrical connection produced in this way also has a sufficiently high reliability and service life if, for example, it is mounted on a traffic route without further measures and is burdened, for example, with salt water and exhaust fumes, etc. over long periods of time. This is because the described soldering or bonding takes place over a large area and protects itself by the - protected against outside - metallic films over a large area itself, so that an attack of the mentioned aggressive media can only take place from the very narrow edge. Of course, an additional protection, for example, these edges can be achieved in a simple manner by spraying or pouring one of the specially available for these purposes commercially available plastic.

In extreme cases, where it depends on the highest security of the electrical connection, the connection between the inventive light source and flat conductor may be provided with a water vapor and gas-tight enclosure. This can be achieved, for example, by enveloping the light source according to the invention with the soldered flat conductor by means of the known plasma polymerization process with a thin - ie a maximum of a few μm thick - PTFE-like, water-repellent and extremely well-adhering layer, for example. Under certain circumstances, ie, for example, with low mechanical stress of the joint, can be dispensed with a soldering or bonding when the freed from the electrically insulating and mechanically connecting layer zone is not deep and when the remaining electrically insulating and mechanically connecting layer, the free ends of the seeks to hold together two metallic films by elastic forces and, if necessary, if the facing sides of the two metallic films additionally have a "pointed roughness".

Of course, more expensive clamping mechanisms are conceivable, which then also able to withstand high mechanical loads on the joint.

The resulting connection point between the flat conductor and the light source according to the invention becomes at most as thick as the light source according to the invention itself.

The flat conductor, which has at least the compressive strength of the inventive light source thanks to the described construction, can be performed over long distances, for example, also over traffic routes, without being an obstacle for wheels or feet. Of course, however, other conventional power supplies are conceivable.

In the following, the planar, intrinsically pressure-resistant and impact-resistant light source according to the invention will be explained with reference to exemplary embodiments. Fig. 1 shows a schematic oblique view of the pressure-resistant base member and the light-generating elements containing carrier.

FIG. 2 shows schematic sections through two variants of the pressure-resistant base element and of the carrier which contains the light-generating elements.

3a to 3h schematically show different embodiments of through holes through the pressure-resistant base member.

Fig. 4 shows schematically a variant of the embodiment of the light-generating elements containing carrier.

5 shows a schematic oblique view of the pressure-resistant base element, of the support which contains the light-generating elements, and of an additional element with optical elements for shaping the light distribution.

6 shows schematically different embodiments of optical elements of an additional element with optical elements for reshaping the light distribution.

Fig. 7 shows schematic sections through a variant of the pressure-resistant base element and the thin carrier, which allows attachment between these two elements by means of positive locking. Fig. 8 shows schematically a view of a further embodiment of the inventive light source.

Figure 1 shows the schematic diagram of a section of a pressure-resistant flat base element 1, with through holes 2 and guide holes 3a.

In addition, the schematic diagram of a section of a carrier element 5 with light-generating elements 6 and guide holes 3b is shown.

The pressure-resistant base element 1 is for example an injection molded part made of epoxy resin. To increase the compressive strength of the resin may be filled with metal powder, wherein the proportion of metal powder, for example, about 50%. An additional advantage achieved by such a metal admixture is improved thermal conductivity of the resin. To increase the strength against alternating stress, the resin may be filled with fibers such as carbon fibers or glass fibers, if need be in addition to a proportion of metal powder. Advantageously, the orientations of the individual fibers of this fiber reinforcement in the present case of a random distribution, which can be achieved by a simple mixing process.

However, the pressure-resistant base element 1 can also be produced by means of die-casting, in which case a metal alloy is used, for example, based on aluminum, zinc, magnesium or copper.

The thickness of the sketched in the example of Figure 1 base element 1 is for example 1 to 5 mm. The smallest diameter of the here conically sketched Through holes 2 is for example 0.3 to 1 mm, the largest diameter, for example, 0.5 to 2 mm.

The through-holes are arranged in the example of Figure 1 in square groups of eight, which are each separated by a zone without through holes from each other. The dimension of such a group of eight is for example 3x3 to 10x10 mm. The width of the zones without through holes is for example 1 to 5 mm.

In the sketched example of Figure 1 2 guide holes 3a are arranged in the respective center and peripherally to the vertices of the eight groups, which in the assembly of base member 1 with the support member 5 - as discussed below - plays an important role.

In addition, the base element 1 may have channel-like depressions 4. These channel-like depressions run along the central axes of the zones without through-holes. Their function is multiple: First, they can - as discussed below - in the assembly of base element 1 with the support member 5 play an important role. Second, they represent predetermined bending and / or breaking points, which make it possible to bend the planar and robust light source according to the invention after completion in one direction. Thirdly, they facilitate a possible severing of the planar and robust light source according to the invention after completion in sections.

The channel-like depressions and, if present, the guide holes (they are in places where tensions would be greatest if they were bent, if they were not present) so in addition to the separability also allow a Three-Dimensional Deformability: By separating desired pieces and then selectively bending, a variety of 3-dimensional entities can be created, for example, a light source that can be fitted into a corner. Another important application of 3D-deformed light sources are car lights adapted to the body shape, for example.

The light-generating elements 6 are arranged in the sketched representation on the carrier element 5 such that in each case the mid-perpendicular to the light-emitting surface of the light-generating element coincides with the central axis of a through-hole 2 of the base element 1. In the example, the light-generating elements 6 are sketched as an LED chip with, for example, the dimensions 0.2x0.2x0.2 to 0.5x0.5x0.5 mm.

The carrier element 5 has, for example, a three-layer structure: a first continuous layer 5a consists for example of a 0.1 mm thick copper alloy. A second layer 5b is, for example, a 0.025 mm thick insulation layer made of a suitable polymer, which separates the first and the third layer 5a and 5c electrical and mechanically connects. Alternatively, the second layer 5b may be constructed of a much thinner electrically insulating material. Thus, it is possible to achieve similar values for isolation and mechanical bonding by means of a glass sol gel, an Ormosil or an Ormocer layer, even if this layer is only 0.5 to 1 μm thick. Another alternative is to realize the second layer 5b by means of a likewise only 0.1 to 01 μm thick silicon oxide or a silicon-oxy-nitride layer.

The third layer 5c, which in turn is electrically conductive, consists for example of a 0.05 mm thick copper alloy. The second and the third layer 5b and 5c, have openings 7 through which the LED chip 6 can be fixed and contacted with its, a first electrical contact-containing rear side by means of conductive adhesive or by means of solder on the layer 5a. The second electrical contact of the LED chip 6 is connected by means of a wire bond 8 with the third layer 5c. In the manner described an electrical parallel connection of all light-generating elements. Of course, other structurings of the layers 5b and 5c are also possible, which allow, for example, groups of 8 light-generating elements to be electrically connected in series and these series groups to be electrically parallel.

Although for the production of the two outlined in Figure 1 elements, namely that of the base member 1 and the support member 5 with light-generating elements 6, with respect to the dimensions and accuracies to be complied with in each case to the limit of the technically feasible, occurs here no significant difficulty.

This is different with respect to the positional alignment of the two elements to each other. Here, it must be ensured that the optical axis of each individual one of the light-generating elements coincides as exactly as possible with the central axis of the - nota visually effective - through-holes. This alignment problem is not trivial and will be the more difficult the larger the two elements 1 and 5 are to be made and united.

FIG. 2a shows the schematic diagram of a cross section through a base element 21 and a carrier 25, which correspond to those shown in FIG. Thanks to the manufacturing method - an advanced printed circuit board technology - of the light generating elements 26 having carrier 25, it is no great effort within the same over relatively large areas, for example, 50x100cm to maintain a relative positional accuracy of the light-generating element of, for example ± 5 microns.

The situation is different with the flat, pressure-resistant base element 21. Here, the compliance of such accuracies over large areas - at least in the case of metal die casting - almost impossible. In the case of die-cast parts, at best a relative accuracy of two geometric elements, which are several tens of centimeters apart, of approximately ± 50 μm can be maintained at best. This means that, for the example sketched in Figure 2a, the narrowest diameters of the through holes 22, which are to be found in the light-generating elements 26, must be at least 120 to 150 μm larger than the diagonal dimension of the light-generating elements and that with a misposition between the optical axis of a light-generating element 26 and the center axis of the corresponding through-hole 22 of up to 60 microns must be expected. This is highly undesirable.

FIG. 2 b outlines a remedy that is simple and inexpensive to implement. The flat and pressure-resistant base element is divided here into island-like subgroups 27 with the aid of the channel-like depressions 24a and with cut or break lines 24b, which are aligned in each case exactly by means of the guide holes 23 to a corresponding subgroup of light-generating elements 26. For this purpose, the procedure is as follows: The flat, pressure-resistant base element 21 is produced as a whole over a large area. Before being joined to a carrier element 25 of corresponding size, it is fixed over its entire surface, for example by means of negative pressure, on a machining and assembly tool. Here, in a next step, for example by means of a punching tool, by means of breaking or by means of laser cutting, it is severed into the subgroups 27 mentioned in such a way that these subgroups maintain their position on the processing and assembly tool. In a next step, the support member 25 with the light generating elements 26 as a whole put on an auxiliary tool, which has at least two of the positions per group of eight which correspond to the guide holes 23, a conically tapered up, exact auxiliary mandrel. Thereafter, the fixed on the mounting tool subgroups 27 of the flat, pressure-resistant base member 21 with their guide holes 23 are all put together on the corresponding auxiliary mandrels, released from the assembly tool, carefully pressed onto the support member 25 and by means of a previously applied to the underside of the base member 21 thin connection layer fixed.

The described procedure obviously has the effect that the individual subgroups 27 of the flat, pressure-resistant base element 21 can each align individually with the auxiliary mandrels and thus with the corresponding subgroups of light-generating elements 26 of the carrier element 25. Since these subgroups are relatively small as described above, it is not a problem within these subgroups to maintain a relative positional accuracy of the individual via holes of less than ± 5 μm, thus reducing the maximum expected positional error between light-generating elements 26 and through-holes 22 to 10 μm , This is good enough.

The described procedure of large-scale production of the pressure-resistant base element and its division into - very close to each other - subgroups during the assembly process offers, in addition to solving the alignment problem, the following advantageous properties:

First, thanks to the described method of production, the production costs remain very low. Secondly, the light source according to the invention, thanks to the subgroups 27 located very close to one another, remains just as pressure-resistant and robust as with a base element 21 not divided into subgroups 27.

Third, thanks to the base element 21 divided into subgroups 27, the light source according to the invention can be spatially, i. to shell-like bodies, to be deformed. Here, the entire subgroups 27 remain as flat structures, while the thin carrier 25 is plastically deformed in the intermediate zones. The deformation process can thus be carried out so far that the carrier element 25 is not destroyed in the plastically deformed intermediate zones.

Fourth, thanks to the base element 21 divided into subgroups 27, the light source according to the invention is substantially less sensitive to high temperatures, which occur due to a dense arrangement of light-generating elements 26. If the pressure-resistant flat base element 21 is not made of the same material as the metallic layers of the carrier element 25-and this is usually the case-then at a non-subdivided base element 21 at very high temperatures, a very high thermal expansion would result in very high tensile forces. or compressive stresses between base element 21 and carrier element 25 occur, which would possibly lead to a drastic reduction in the lifetime of the inventive light source. Thanks to the division into relatively small subgroups 27, these effects are minimized to such an extent that they are irrelevant.

Figures 3a to 3h show sections through exemplary different ones

Ausprägungsprinzipien the optically effective through holes 32 through the pressure-resistant base member 31. As a rule, there is an optically effective through hole according to the invention of at least two components, namely an optically effective through-opening 32a and an optically active and - in the wavelength range of the radiated light from the light-emitting elements 36 - optically transparent filling 32b.

FIG. 3a shows the simple case of an at least approximately cylindrical passage opening 32a and an optically transparent filling 32b. In the sketch shown in FIG. 3a, the optically transparent filling has a continuously spherically or aspherically shaped surface. Of course, the optical function of this surface shape can also be realized by means of a fresnel-like or provided with corresponding diffractive patterns surface. It goes without saying that the shape of the surface can be a flat surface in extreme cases.

The at least almost cylindrical passage opening 32a shown in FIG. 3a is particularly simple for reasons of manufacturability. A large number of the passage openings 32a can each be produced simultaneously by means of a very cost-effective punching process. If this punching operation is carried out in a possible somewhat more elaborate variant so that a simultaneous pressing and / or rubbing process takes place, surfaces can be produced which have good surfaces in the sense of a mirror. Of course, the at least almost cylindrical passage openings 32a can also be produced by means of a die casting or die casting process.

The optical function of such an at least almost cylindrical passage opening depends on the nature of its surface structure. In a diffuse - at most black - surface, the almost cylindrical passage opening acts as a diaphragm, which hides all light outside a certain solid angle. The tangent of this maximum solid angle below which in this case light emerges from the passage opening 32a is obviously given by the ratio of cylinder radius to cylinder height. If, for example, the cylinder radius is 0.5 mm and the cylinder height corresponding to the thickness of the pressure-resistant base element is 2 mm, this results in a maximum exit angle of approximately ± 14 °. Of course, such a limitation of the exit angle is paid in this case by enormous light losses. For example, if LED chip are used as light-generating elements 36, they give their light almost uniformly within a solid angle of about ± 80 ° and acting as a blend almost cylindrical passage opening 32a destroys all light in the solid angle range between ± 14 ° to ± 80 ° , In the case of a reflecting surface of the passage opening 32a, the light emitted in the solid angle range between ± 14 ° and ± 80 ° also reaches the upper surface of the transparent filling 32b, where it emerges in a solid angle which depends on the shape of this surface - is between about ± 60 ° to ± 90 °.

FIG. 3b shows the somewhat more complex case of a conically formed passage opening 32a.

Depending on the opening angle of this cone, a different manufacturing method must be selected. For small opening angles, a punching / pressing operation can be used, which is carried out such that first a through-hole is punched with the diameter of the smallest cone opening and then a pressing process takes place in the same stroke, which produces the conicity of the through-opening 32a. For larger opening angles, the injection or pressure casting method must be used. With regard to the optical effect of the example sketched in FIG. 3b, reference can be made to the considerations made with respect to FIG. 3a. In the case of a diffuse surface of the passage opening 32a, an exit angle increased corresponding to the opening angle of the cone. In the case of a reflecting surface significantly smaller exit angles (about ± 50 °) and a better optical efficiency than in the case 3a can be achieved.

In Figure 3c, the example of a passage opening 32a is sketched with the approximate shape of a parabolic mirror.

Since a passage opening 32a formed in this way makes sense only with a well-reflecting surface, a pressure-resistant base element 31 having such passage openings 32a is preferably produced by means of injection molding or diecasting. In cases where the material used for this purpose results in a not or only insufficiently reflective surface, followed by an additional coating step to produce a well-reflective surface. This coating step may, for example, be a galvanic deposition of one or more metal layers, which is preferably carried out so that at the same time a smoothing of the surface takes place. The coating step can be - if necessary in combination with previous galvanic steps - but also in a vacuum performed sputtering or sputtering process.

The optical function of the reflecting surface of the passage opening 32a formed in accordance with FIG. 3c is clear. It should be bundled as large a proportion of the light emitted from the light-emitting element 36 light in a solid angle, which is smaller than that which can be reached with a conical passage opening. Depending on the height of the passage opening, solid angles down to ± 10 ° can be achieved in this way. In figure 3d, the example of a through-hole 32a is sketched, which has the approximate shape of a two-stage parabolic mirror. This two-stage parabolic shape is coupled to a filling of the passage opening 32a at which the filling level of a first optically transparent material 32c, for example with a high refractive index of 1.6 or higher, for example, corresponds to the height of the first nearly parabolic step of the passage opening 32a and at which is the remaining height of the through hole 32a, at least partially filled with an optically transparent material 32b having, for example, a lower refractive index of, for example, 1.3 to 1.6. If required, instead of a two-stage mold, a suitably designed multi-stage mold can also be selected.

When using LED chip as the light-generating elements 36, the optical function of a through-hole 32 made in this way is as follows: Since the surface of the LED chip usually has a very high refractive index (2.5 to 4), the high refractive index of the first one can Fill region 32c a significantly increased proportion of light from the surface of the LED chip 36 are coupled out. Since optically transparent materials with a high refractive index are generally very expensive, it is for this reason that it is impossible to fill the entire passage opening with this material. The second advantage of a two-stage filling is that the enlargement of the exit angle which occurs by optical refraction at the exit from the optically highly refracting material 32c, by means of the two-stage parabolic shape of the passage opening 32 a can be largely compensated, so that at the exit from the optical lower refractive material 32b possibly desired small exit angle can be maintained.

In FIG. 3e, the example of an oblique passage opening 32a is sketched, which has the approximate shape of an oblique parabolic mirror. Of course The parabolic shape could be replaced by a corresponding multi-stage parabolic or an oblique cylindrical or conical shape.

The optical function of such a through-hole formed is that the light emerges in a solid angle range which is inclined relative to the vertical with respect to the lugs 3a to 3d by a certain amount, for example 10 ° to 30 °.

In Figure 3f a variant is outlined in which, for example, roughly punched through hole 32a does not perform any optical function, but only protective function. The filling 32b with optically transparent material takes place here so that, irrespective of the quality of the surface of the passage opening 32a, a substantially cylindrical body with a spherical or aspherical shape arises at the upper end, in which the light is transported by total reflection to the lens-like end of the filling 32b becomes where it exits in a defined solid angle range.

In the embodiment according to FIG. 3g, the passage opening has, similar to FIG. 3c, a parabolic-mirror-like shape and, for example, is likewise coated in a reflective manner. In contrast to Fig. 3c, however, it is not almost completely filled with transparent material, but instead there is only a droplet 32d ("globe top") made of a transparent material which shields the LED and deflects light, for example, the drop may be made of silicone and fills less than 30% of the passage opening.

According to FIG. 3h, in contrast to the embodiment of FIG. 3c and of FIG. 3d, transparent material 32b-for example likewise silicone or, for example, a curable material-fills transparent material - the passage opening only partially. The section-wise parabolic-mirror-like course of the reflective opening surface is adapted accordingly: since the light is refracted away from the optical axis at the interface between the transparent material and the air, the opening angle at the location of the optically thinner medium (the air) must be greater; so that reflected radiation is collimated. The opening surface thus has a first portion 39a and a second portion 39b at a greater angle than the first portion. The surface of the transparent material 32b coincides approximately with the transition between the first and second portions. Moreover, in the illustrated embodiment, the surface of the transparent medium is shaped to be optimized in a central portion 32g for collimating light directly from the LED 36, whereas a second portion 32f collimates light once reflecting from the first parabolic mirror-like portion has been. In the figure, three exemplary beam paths are shown. The effect of the first and second surface sections can also be achieved by corresponding diffractive structures.

FIGS. 4a to 4c show the exemplary sketches of an embodiment of the planar, robust light source according to the invention, which emits the light essentially at right angles to both surfaces of the light source.

For this purpose, nothing else is necessary to provide the thin carrier 45 there with holes, where later the light-generating elements 46, so for example LED chip to be located. The LED chip 46 then "floats" effectively at the two wire bonds 47 with which they are electrically contacted.To achieve this, an auxiliary film 49 is first attached to the underside of the thin carrier 46 so fastened that they have a momentary hold, but later can easily be detached again For example, done with an optically transparent silicone gel that adheres only minimally to the auxiliary film 49. Thereafter, the LED chip are electrically contacted and fixed by means of the wire bonds 47. In a next step, a mechanical stabilization takes place in that in the region of the LED chip 46 and the nearby edge of the thin carrier 45 a thin as possible, the optical requirements sufficient plastic layer 47, so for example a suitable silicone gel is applied.

In a next step, as outlined in Figure 4b, the thus equipped thin carrier 45 is connected to the pressure-resistant base member 41, wherein the at least at this time still viscous plastic layer 47 is pressed into the corresponding cavities 42c of the pressure-resistant plate 41 in laterally something flows out. Firstly, a perfectly filled optical path is ensured and, secondly, a sufficiently good adhesion between the two components 41 and 45 is achieved. In a last step, the auxiliary film 49 is now removed.

Of course, as outlined in FIG. 4c, a pressure-resistant base element of the same design or provided with other optical properties can now also be fastened on the underside of the resulting light source according to the invention.

FIG. 5 outlines the basic example of the case in which the planar, robust light source according to the invention has an optically effective additional element 57 in addition to the pressure-resistant base element 51 and the thin support 55 equipped with light-generating elements 56. This additional element 57 is constructed in the example shown that it consists of a pressure-resistant plate 58 with optical elements 59 in corresponding openings. Of course, the position of this optical element 59 is chosen so that they correspond to the optically effective through-holes 52 of the pressure-resistant base member 51.

FIGS. 6a to 6d sketchily show some possible embodiments of the optical elements 69 of the additional element 67.

In Figure 6a, the optical element 69 has no actual optical effect, but is in the form of an optically transparent flat plate, which is embedded in a pressure-resistant plate 68, formed as additional protection of the optically active through hole 62.

In Figure 6b, the additional element 67 consists only of an optically active plate 69, which is provided for example with a surface structure that produces a broad diffuse radiation of the light. Of course, this plate must have a sufficiently high compressive strength to be suitable for the intended applications. As a rule, it is sufficient to use a plastic such as PC or PMMA. In certain cases, glass can also be used.

In Figure 6c, the optical element 69 of the additional element 67 takes over the function of an extension of the parabolic shape of the through hole 62 through the pressure-resistant base member 61. For this purpose, the pressure-resistant plate 68 of the additional element 67 at the corresponding locations corresponding parabolic through holes, which together with a corresponding optically transparent filling the optical element 69 form. FIG. 6d outlines the case of an additional element which has the task of emitting the light in a nearly horizontal direction.

For this purpose, for example, a pressure-resistant base element 61 is used, which has obliquely parabolic through-holes 62, so that the light exits at the upper end of these through-holes, for example at a mean solid angle, which is inclined by approximately 20 ° relative to the vertical.

This light is deflected by the prismatic shape of the optical element 69 of the additional element 67 further in the horizontal direction, so that it finally emerges substantially in a solid angle range of 3 ° to 40 ° relative to the horizontal from the upper surface of the optical element 69.

In the sketched example of FIG. 6d, the additional element is drawn in such a way that the optical element 69 extends over a plurality of through-holes 62, with the result that an addition of the light intensities occurs in the emission region.

The optical element 69 is embedded in corresponding holes of a pressure-resistant element 68, so that even when choosing a soft or brittle material for the optical element 69 a total of a pressure-resistant additional element 67 is formed.

Alternatively, the optical element can also be embedded in holes in the base element - correspondingly thicker in design - which eliminates the need for an additional pressure-resistant element 68. The additional element can also be provided with means which influence the color of the emitted light, for example filters, etc. For runway markings and, for example, also other applications, light sources are particularly interesting which have an angle-dependent color emission. Such can be effected with an optically active element which deflects light in at least two different, defined directions. There is a separate color filter for each direction. This can also be achieved without difficulty in a very flat light source according to the invention, for example with fine, Fresnel lense-like prismatic structures on the surface which diffractively and / or refractively have light-emitting surfaces differently colored for the different directions.

FIGS. 7a and 7b show schematic sections through a variant of the pressure-resistant base element 71 and the thin carrier 75, which permits a fastening between these two elements by means of positive locking.

For this purpose, as outlined in FIG. 7a, the guide holes 73a of the pressure-resistant base element 71 on the lower side are provided with an extension 73b projecting annularly over the surface of the pressure-resistant base element 71, for example. The height of this extension corresponds approximately to twice the thickness of the thin carrier 75.

The guide holes of the thin carrier have a diameter which is, for example, one micron larger than the diameter of the annular extension 73b. So that when joining the two elements 71 and 75 no problems occur, it is advantageous if the outer jacket of the substantially annular extension 73b is conical.

In Figure 7b, the two elements 71 and 75 are sketched in an assembled state, in which the annular extension 73b is formed after rivet-like outward and thus forms the desired positive connection between the two elements. For this purpose, the joining process is carried out, for example, in such a way that the auxiliary pins used for joining are shaped at their lower end in such a way that the required deformation of the annular extensions 73b takes place by pressing on the base element 71.

Thus, for example, a light source is provided which has the following properties:

The light source is planar in the sense that it can be applied to given surfaces such as car terraces, runways of airfields, walkways, corridors and walls of buildings without incorporation into any wells without being a major obstacle to wheels rolling over them or creates a risk of tripping or a risk of injury; and which is flameproof in the sense that the light source is able to withstand the alternating load created by, for example, tires or airplanes rolling over it, or the high local pressures encountered, for example, entering the high-heel women's footwear light source can. For this purpose, for example, it has a light-generating electroluminescent elements, for example unhoused LEDs or OLEDs surrounding flat and pressure-resistant housing, which are provided with measures which bring about a compressive strength even when the light source has a large surface area - here composed of carrier and base element. This is due to the fact that each subarea of the light source is inherently pressure-resistant in that the pressure is recorded in a planar manner - here in load-bearing zones - and transmitted to the underlay of the light source. The compressive strength is, for example, at least 30 N / mm, even for pressures acting on surfaces of less than 1 cm. In addition, it is thin, ie, for example, 5 mm or thinner.

According to a preferred embodiment, it is characterized by being robust in the anti-impact sense, such that it can withstand vandalism violent blows carried out, for example, with bottles or similar objects so as to withstand some such impacts without significant loss of luminosity, which means that it may fail locally but continues to emit light over a large area.

Additionally or alternatively, it may also be characterized by being robust in the sense that the light source is so gas and water vapor tight that all components contained in it, such as light-generating elements, electrical connections, optical elements, etc. have a high minimum life of, for example, 20O00 to 100,000 operating hours.

It may be characterized in that it has a user-definable spatial light emission and light color distribution in the sense that the light source according to the invention emits its light depending on the design: that, for example, from each light emitting point of the planar light source, the light emanates in the same defined solid angle perpendicularly or at a desired mean inclination to the surface of the light source, this defined solid angle depending on the embodiment, for example, between ± 10 ° to ± 80 °;

that the light emanates, for example, from the light-emitting points of the planar light source in different defined solid angles and distributions;

that, for example, the light leaves the light source through the lateral boundaries of the light source and / or through the upper surface substantially in the lateral direction in a defined solid angle;

that, for example, the light leaves the light source not only on one of the two-dimensional sides, but also exits in the same or different light distribution to both flat sides and / or possibly additionally from the lateral surfaces of the light source.

In the embodiment according to FIG. 1, the base element 1 has channel-like recesses 4 which, as described, can serve different purposes. The Baisiselement is but essentially one piece. Instead, the base element can also decay into subelements, as shown with reference to FIG. 2b. It can therefore be separated along, for example, straight and web-like dividing lines. The individual sub-elements can each have several Through holes for one LED and as required as explained still have guide holes.

In Figure 8 is - very schematically - drawn a plan view of an embodiment in which each sub-element 87 has exactly one through hole 82 for an LED 86. The dividing lines 88 extend in a network or grid-like manner and separate the base element 81 into the sub-islands.

The LEDs are protected against moisture and environmental influences by the transparent mass of the type described above, which is introduced only after the application of the partial elements 87 on the base member 81.

In the case of subsequent dicing, the entire panel merely has to be divided along already existing dividing lines 88 in the base element. Under certain circumstances, only the support element must be shared.

A based on the 'sub-element' principle light source thus has a plurality of unhoused elektrolumineszentn elements on a support carrying them and a pressure-resistant, surface defining a base member which is mechanically connected in bearing zones with the carrier that pressure on the surface of Base element is derived on the support, wherein the supporting zones are distributed over substantially the entire surface of the light source, wherein the base element consists of a number of juxtaposed sub-elements, which are each associated with at least one electroluminescent element, and wherein carrier and base element together a pressure-resistant plate-like unit of total thickness of 1 cm or less. In addition to the embodiments described here, there are innumerable other ways in which the invention can be realized. For example, the base member may be formed as an at least partially transparent body molded with the carrier, with the supporting zones then extending over the entire surface of the carrier, with the exception of the light-generating elements and possibly the rim. However, this embodiment has the rather important disadvantage that the thermal expansion of the base element must be matched with high precision to that of the carrier, since otherwise shear forces act on the light-generating elements.

Incidentally, the light source according to the invention can be combined with further modules having complementary functionality, for example with modules which optimize the cooling. Reference is here made to the applicant's Swiss patent application 584/03. In particular, the approaches to passive or active cooling by means of guided convection described in this application are suitable, depending on the application, to be used in combination with the approaches described here.

Claims

A light source having a plurality of light-generating elements (6, 26, 36, 46, 56, 66, 16, 86) and a support (5, 25, 35a-c, 45, 55, 65, 75) carrying the light-generating elements comprising a pressure-resistant, surface-defining base member (1, 21, 31, 41, 51, 61, 71, 81) which is in supporting

Zones is mechanically connected to the carrier, that pressure is transferred to the surface of the base member on the support, wherein the supporting zones are distributed over substantially the entire surface of the light source, characterized in that the light-generating elements are unhumed electroluminescent elements and that Carrier and

Base element together form a pressure-resistant, plate-like unit of a total thickness of 1 cm or less.

2. Light source according to claim 1, characterized in that the base member is plate-like and a plurality of holes (2, 32a-b, 42a-b, 52, 62, 82) which penetrate the base member, wherein the holes are arranged in that its position corresponds to the arrangement of the light-generating elements.

3. Light source according to claim 2, characterized in that the holes are filled with at least partially transparent material, which is preferably in direct contact with the light-generating elements.

4. Light source according to claim 2 or 3, characterized in that the thickness of the base element, the expression of the holes and optionally the refractive index of befindlichem in the holes, at least partially transparent material are selected so that the solid angle range in which order a central Outlet direction around light is emitted, at most ± 30 °, preferably at most ± 20 ° and, for example, at most ± 10 °.

Light source according to one of claims 2 to 4, characterized in that the holes have mirrored hole walls.

Light source according to claim 5, characterized in that the hole walls extend at least partially parabolspiegelartig.

7. Light source according to one of claims 2 to 6, characterized in that there are at least 10 holes per cm, to the position of which a light-generating element can be attached.

8. Light source according to one of the preceding claims, characterized in that its thickness does not exceed 7 mm, preferably 5 mm and, for example, less than 3 mm or less than 2 mm, so that they applied to a surface no major obstacle to rolling over them Wheels is generated and no risk of tripping or injury.

Light source according to one of the preceding claims, characterized in that it can withstand pressure loads of at least 30 N / mm without significant plastic or elastic deformations.

10. Light source according to one of the preceding claims, characterized in that the supporting zones are distributed so that acting Pressure is also dissipated when acting on a local area of 1 cm ² or less.

11. Light source according to one of the preceding claims, characterized in that the supporting zones occupy at least 50%, preferably at least 70% of the surface of the light source.

12. Light source according to one of the preceding claims, characterized in that carrier and base element auxiliary surfaces (3a, 3b, 23) which fix with or without additional auxiliary elements carrier and base element in the correct relative position.

13. Light source according to one of the preceding claims, characterized in that the base element has a plurality of laterally adjacent sub-elements (27, 87).

14. Light source according to one of the preceding claims, characterized in that the carrier has on its top and bottom depending over its entire extent reaching metallic surfaces, which are suitable for electrical contacting.

15. Light source according to one of the preceding claims, characterized by an optically active additional element (57, 67).

16. Light source according to claim 15, characterized in that the additional element acts lichtumlenkend.

17. Light source according to one of the preceding claims, characterized in that power supply means of the light-generating elements are at least partially planar and formed so that local, localized destruction can never cause large-scale light failures.

18. Light source according to one of the preceding claims, characterized in that it is bendable along defined lines (4), without the functionality would be impaired.

19. Light source according to one of the preceding claims, characterized by predetermined separating lines (4), along which they subsequently work in their own right

Subunits is separable.

20. A method for producing a light source according to any one of the preceding claims, wherein the base member prepared and the carrier provided with the light-generating elements and is then mechanically connected in the areas of the bearing zones with the base member.

A light source having a plurality of light-generating elements (6, 26, 36, 46, 56, 66, 76) and a support (5, 25, 35a-c, 45, 55, 65, 75) carrying the light-generating elements a pressure-resistant, a surface defining base member (1, 21, 31, 41, 51, 61, 71, 81) of one or more juxtaposed sub-elements (27, 87), which are each associated with one or more light-emitting elements, wherein the base element in bearing zones is mechanically connected to the carrier, that pressure on the surface derived from the base member to the carrier is, and wherein the supporting zones are distributed over substantially the entire surface of the light source, characterized in that the light-generating elements are unhumed electroluminescent elements and that carrier and base element together form a pressure-resistant, plate-like unit of a total thickness of 1 cm or less.