EP1593109A1

EP1593109A1 - Optical element for variable message signs

Info

Publication number: EP1593109A1
Application number: EP03779554A
Authority: EP
Inventors: Franz Silhengst; Alexander Otto
Original assignee: Swarco Futurit Verkehrssysteme Gesmbh
Current assignee: Swarco Futurit Verkehrssysteme Gesmbh
Priority date: 2003-01-31
Filing date: 2003-12-23
Publication date: 2005-11-09
Anticipated expiration: 2023-12-23
Also published as: AT500013A1; WO2004068447A1; DE50311404D1; AU2003287758A1; ATE428162T1; AT500013B1; EP1593109B1

Abstract

Disclosed is an optical element which can be used mostly in a randomly arranged plurality for representing symbols or graphic information on substantially vertical front faces of variable message signs. Said optical element comprises at least one triggerable light source (2), mostly an LED that can rest on a circuit board (1), a lens element (3) that is provided with a light-incident area (4), a surface area (6), an exit area (5), and preferably a housing (12) surrounding at least one portion of the surface area (6), light being emitted in an essentially horizontal to descending direction. The surface area (6) is provided with a maximally light-absorbing area (9) which directly borders the light incidence area (4) and the exit area (5) of the lens element (3). The length of the lens element (3) is greater than the diameter thereof. The curvature of the exit area (5) at each surface point is embodied such that substantially all light beams (10) emitted by the light source (2) are directed into an area located below a given angle S, preferably less than or equal to 10 DEG , relative to the horizontal line while essentially all light beams (11) inciding from outside at an angle that is greater than or equal to S relative to the horizontal line are directed onto the absorption area (9).

Description

Optical element for variable message signs

The invention relates to an optical element, which can usually be used in an arbitrarily arranged number of Niels in essentially vertically arranged front surfaces of variable message signs for the representation of symbols or graphic information, consisting of at least one controllable light source, usually an LED, which can sit on a circuit board, one Lens element with light entry surface, outer surface and outlet surface and preferably a housing surrounding at least part of the outer surface, with essentially horizontal to downward inclined light radiation, the outer surface having a maximum light-absorbing absorption surface.

Since it has been possible to manufacture light-emitting diodes (LED) with high light concentration, light intensity and lifespan in a number of colors or in almost all specified signal colors, this technology has been intended to replace the fiber optics previously used in variable message signs. However, use in graphics-capable displays is also being promoted because, with the appropriate wiring, each LED can be controlled individually and therefore individually programmable displays and information are possible.

Light-emitting diodes differ from conventional incandescent lamps not only in the way they produce light using semiconductor technology, which generates almost monochromatic colored light, but also in the form of integrated optical measures for light control, which on the one hand improve the proportion of ambient light and on the other hand produce universal, favorable light distribution characteristics in narrow and wide-angle versions, so that the LED can be used directly as signal light without any further optical measures.

While there are no overriding regulations for advertising and information signs with regard to their lighting properties, there have been those in the field of traffic engineering for a long time, in particular light color, brightness, Light distribution, uniformity, a high contrast ratio and the associated low phantom light (noise of an activated signal light by incident sunlight) are prescribed. The commercially available LED designs only partially meet these requirements, but are still used as long as customer-specific versions of the LED are uneconomical and many manufacturers currently have to reject them for technological reasons.

If the LEDs are used directly in traffic engineering without additional optical measures, the light color, brightness and uniformity usually meet the requirements, the required light distribution can often only be achieved by adding additional lenses, but the main problem is the high phantom light. The lens tip of the usually crystal-clear transparent LED body bundles incident sunlight directly onto the highly reflective internals inside the LED, such as the reflector and reflector edge, connecting lugs and contact points, from where it is reflected. Because of the crystal-clear LED body, the phantom light is also relatively whitish and unfiltered and may appear brighter than the actual signal light when the sun is unfavorable.

In traffic technology, standards stipulate that the position of the sun is assumed to be 10 degrees perpendicular to the optical axis of the signal, usually the direction of maximum light radiation, for phantom light assessment. At such angles, additional measures must be taken to limit the effect described above. Because the optics are often arranged relatively close to each other, the smallest possible diameter of the optical element is an important criterion.

Some known measures are the attachment of a relatively large converging lens at a greater distance in front of the LED, which is problematic due to space constraints. Small sun visors over each lens make cleaning more difficult and limit the observation area. Pinholes in front of each LED require an additional front screen for cleaning reasons.

Another measure consists in the use of lenses or LED bodies colored in the signal color. The sunlight has to pass through the colored component twice, whereby the foreign color components of the light are filtered out, the LED light only once, whereby the coloring is as transparent as possible for the actual signal color. As a result, the sunlight is significantly weakened, the useful light is reduced to a much lesser extent. A disadvantage is not only the lower useful light intensity, which has to be compensated for by a higher number of light points, but also the phantom light in signal color, which is regarded as particularly critical in many applications compared to white phantom light.

Another disadvantage is the usually circular-symmetrical light emission of the light-emitting diodes, so that a large proportion of the light is emitted unused into irrelevant areas unless optical measures are also taken. In addition, commercially available light-emitting diodes have radiation characteristics that generally do not match the required light distribution of the light points well. As a result, disproportionately more LEDs often have to be used without additional optics, only to have enough light in poorly lit areas. In many cases, the required light distribution cannot be achieved at all without additional measures. Therefore, good devices consistently use front lenses, which can achieve the desired distributions very effectively. At the same time, measures are also taken against phantom light.

In the application EP 0 930 600 AI, the light of an LED is focused by means of a converging lens either onto a diverging lens or in particular onto an aperture between the collecting and diffusing lenses and directed into the prescribed range by means of the diverging lens. Sun rays are absorbed either on the housing wall or the panel.

This version has the advantage that practically no sunlight can get into the LED. The LEDs can be wired individually or sit together on a circuit board. Any arrangement of individual optics is also possible. The optics diameter is relatively small.

A disadvantage is, however, a variety of components that have an unfavorable impact on costs and also make automatic production very difficult, but also the large number of interfaces that light must penetrate and suffer from loss of brightness, in particular that sunlight also creates surface reflections at least on the one - and exit surface of the scattering lens before it is absorbed. This creates phantom light again, which affects visibility.

EP 1 227 458 A2 discloses a display and / or signal device for light-optical information. This device comprises a carrier plate or a housing part with light sources arranged thereon. A lens body provided here is provided with a light guide extension which is arranged in corresponding recesses in the carrier plate. The surface on which the light guide projections rest is provided with a light absorption layer. In the document mentioned, a module is presented which is made of transparent material and has integrated a large number of similar scattering lenses, which direct the light of the LEDs, which are seated on a common circuit board, into the observation area. The inside of the module has a light-absorbing black coating, except for the light entry surfaces, which are located on extensions to save material, so that incident sun rays are absorbed.

This version has the economic advantage that it consists of only one component and a circuit board with LED. The light only penetrates the entry and exit surface of the module, which means that losses are minimal. Sunlight coming in from outside only creates a surface reflection on the front surface, then it is already absorbed on the inside wall of the module.

A disadvantage is the fixed arrangement in a grid, which restricts the use to graphic displays. A separate module is required for each grid dimension. It is particularly disadvantageous that, due to the transparent base body, the transition surfaces between the lenses must be inclined upwards or downwards at any point on the outer surface so that no reflections can occur in the direction of observation, but this results in a highly jagged, particularly dirt-prone surface. Furthermore, by dispensing with a metallic matrix plate, only limited protection against electromagnetic interference or lightning is possible. Nevertheless, a support structure with a vertical sealing surface is required, to which the modules are attached.

International application WO 02/17628 A2 also presents a module made of transparent material with a grid-like arrangement of the LEDs. The optical How it works is so sophisticated that no phantom light is recognized. The sunlight is either absorbed in an internal grille made of black material or directed outside the observation area. In addition to the fixed grid, the extremely complex manufacture of the module as well as the stepped and inclined front, as well as the escape of phantom light, are disadvantageous, even if it does not take place within the observation area.

The aim of the invention is an inexpensive optics for variable message signs, which fulfills the standardized light distributions and has the lowest possible phantom light. It should consist of as few components as possible and should be fully automatic. It should be able to be mounted tightly and precisely both in freely selectable arrangements and in any grid, preferably using a metallic matrix plate, and should have the highest possible packing density.

This is achieved according to the invention in that the absorption surface directly adjoins the light entry and exit surface of the lens element, that the length of the lens element is greater than its diameter and that the curvature of the exit surface is formed at each surface point so that essentially all of the light source Coming light rays in a range below a predetermined angle S, preferably less than or equal to 10 °, with respect to the horizontal and essentially all light rays incident from outside with an angle greater than or equal to S with respect to the horizontal are directed onto the absorption surface.

In the next state of the art, EP 1 227 458 A2, the surface of the carrier plate and its depressions are provided with a light absorption layer. Since the lens bodies completely cover the light absorption layer with their wall areas, this does not border on the light exit surface at any point.Unwanted scattered light can reach neighboring lens bodies via these wall areas, where it produces undesirable effects such as phantom images, similar to a light guide. According to the present invention, this is excluded from the outset, and pulling the absorption layer from the light entry surface to the light exit surface brings about a more extensive light absorption of any external light sources. Further advantageous refinements and embodiments of the invention are identified and illustrated in more detail in the subclaims and the description below, including the associated drawing figures.

The invention will now be explained with reference to the illustrations. 1 shows a vertical section through an optical element according to the invention, FIG. 2 shows a vertical section through another optical element before insertion, FIG. 3 shows a vertical section through a third optical element and a cross section, FIG. 4 shows preferred outlines of the installation holes, FIG. 5 and 6 show combinations of the optical element according to the invention in vertical section.

In Fig. 1, the optical element according to the invention in its simplest embodiment is shown in vertical section. On a circuit board 1, a light source 2 in the form of an LED sits coaxially directly behind a lens element 3 with a light entry surface 4 and an exit surface 5, connected by a lateral surface 6. The exact positioning of the circuit board 1 with the LED is carried out in any manner outside the illustration. The lens element is installed in a vertically arranged, metallic matrix plate 7 and fastened and sealed with an adhesive 8. The outer surface 6 is coated black in the entire lower region between the light entry surface 4 and the exit surface 5, so that any light beam incident thereon is absorbed. This area is referred to as the absorption surface 9. The light rays 10 of the LED enter the light entry surface 4, pass through the lens element 3 and exit the exit surface 5. The light entry surface 4 functions as a converging lens, captures as much light as possible from the LED and bundles it onto the exit surface 5, from which it is directed with the required intensity and distribution into the prescribed observation area. This range is expediently determined in such a way that the greatest intensity occurs in the horizontal axis direction and decreases more or less rapidly towards zero to the side and downwards. No light radiation is required at the top. In addition to the influence of the light source 2 and the light entry surface 4, this radiation characteristic is achieved above all by a suitable design of the exit surface 5 by means of different curvature zones, which are not dealt with in detail here. It can be seen, however, that the light rays 10 drawn are only directed horizontally and more or less downwards. This is supported here by a slight downward inclination of the light entry surface 4. The curvature of the exit surface 5 is on each surface point is designed such that essentially all of the light rays 10 coming from the light source 2 fall into a range below a defined angle S, preferably less than or equal to 10 °, with respect to the horizontal and essentially all from the outside with an angle greater than or equal to S with respect to of the horizontal incident light rays 11 are directed onto the absorption surface 9.

Furthermore, the rays of light coming in from outside, e.g. Sun rays 11 are drawn in, which reach the exit surface 5 parallel to one another at an angle S (vertical angle of the sun) which is fixed to the horizontal. They penetrate into the lens element and are directed through the exit surface 5 onto the absorption surface 9, where they are absorbed. Furthermore, a sunbeam 11a is drawn in, which is incident at a smaller vertical angle than S. It reaches the reflector of the LED, where it is reflected and scattered and creates the dreaded phantom light. However, a light beam 11b is also drawn in, which is incident at a larger vertical angle than S. Accordingly, it reaches the absorption surface 9 earlier and is absorbed.

Particularly in the case of narrowly bundling optical elements, overhead sun rays 11c penetrate furthest into the lens element 3. Therefore, their deflection and thus the design of the upper exit surface area is particularly relevant for a small angle of incidence S of the sun.

The angle S defined for the incident sun rays represents a vertical critical angle. At this position of the sun, just no sun ray 11 can penetrate to the light source 2, it is destroyed on the absorption surface 9. It is immediately apparent that with every higher position of the sun the sun rays 11b hit the absorption surface earlier and that no phantom light is produced. At a lower position of the sun, however, some sun rays 11a already penetrate through the light entry surface 4 into the light source 2 and generate phantom light.

The design of the exit surface 5 is different with respect to the two

Requirements, namely the light distribution of light rays 10 and the directing of sun rays 11 onto the absorption surface 9 do not contradict one another, because that

In principle, lens element 3 rotates according to optical laws Appearance of the bright light entry surface 4 with the black absorption surface on the head adjoining it below, so that it is depicted as a brightly illuminated observation area with a dark zone above it. If the alignment is suitable, no light is emitted upwards.

If the relevant standards now require low phantom light down to 10 degrees of the sun or up to another angle value, this value represents an essential design constant for the geometrical dimensioning of the system and the design of the exit surface 5 the light source 2 outgoing light beams 10 to be taken into account, but also to include reflected and scattered light components. A certain amount of scattered light escaping upwards will therefore be unavoidable. However, if care is taken to ensure that as far as possible no scattered light emerges at an angle S or more, then conversely no sunbeam 11 with the angle of incidence S can penetrate to the light source 2. The exact dimensioning of the optical system and the design of the exit surface 5 is therefore preferably carried out by means of computer simulation because of the complexity of the light propagation.

Of course, any number of optical elements can be installed in the matrix plate 7 in any arrangement. The light sources 2 are then preferably all on the same circuit board 1, which also has other electrical components for voltage supply and control and also all conductor tracks.

FIG. 2 shows a modified optical element in vertical section. The outer surface is designed entirely as an absorption surface 9. The black coating consists of plastic and is thickened to form a solid covering of the lens element 3, which now forms a housing 12. In the area of the exit surface 5, the housing 12 has a flange 13 as a contact surface. Adjacent ribs 14 with sawtooth-like cross-section are attached to the housing periphery. A precise receptacle 15 for the light source 2 is formed in the area of the light entry surface 4. The light source 2 does not sit on a circuit board 1 here, but is directly wired and held by a snap hook 16 formed on the housing 12. Such a design saves the board costs for small quantities. The illustration shows the optical element before pressing. The ribs 14 have a slight oversize compared to the installation hole 17. When they are pressed in, they are deformed elastically / plastically in a known manner, hold the optical element firmly in the mounting hole 17 by means of frictional engagement, and seal at the same time. The flange 13 ensures the precise alignment by contacting the matrix plate 7. The housing material is considerably tougher and more flexible than the material of the lens element 3, so that only the ribs 14, but not the lens element 3, are deformed when pressed in.

In contrast to FIG. 1, the optical element is longer here. This not only reduces the curvature of the exit surface 5 overall, the sun rays 11 have a greater path length in the lens element 3 to the absorption surface 9. Furthermore, the exit surface 5 is designed asymmetrically. The upper region is more strongly curved, as a result of which overhead light rays 10c are deflected more downward, and the overhead sun rays 11c, which otherwise reach the light entry surface 4 first, are more strongly refracted downward and thus reach the absorption surface 9 earlier. These two measures make it possible to achieve a lower sun angle S overall. The light area below the horizontal is therefore preferably illuminated by light beams 11c from the upper area of the exit surface 5.

In particular, it is pointed out that the black housing 12 and the outer surface 6 of the lens element 3 must be optically effectively connected to one another, in particular by melting together. A mere putting together of two individual components would not result in an absorption of the sun rays 11, but rather their total reflection and thus considerable phantom light, despite an identical graphic representation.

However, total reflection may take place in the upper area of the outer surface 6. Fig. 3 shows this embodiment in connection with a particularly wide light source 2 in the form of an SMD LED. These LEDs are inexpensive and can be positioned particularly precisely on the circuit board 1, but only a partial area of the light can usefully be pre-bundled via the light entry surface 4. Light rays lOd that exit particularly far away are therefore directed via a total reflection at the free area of the outer surface 6 through the exit surface 5 into the light distribution area, where, due to the stronger deflection, they brighten the edge areas or of the close range. Inclination and curvature, or also optical surface structures, as well as a more complicated design of the outer surface 6 can be freely selected within reasonable geometric limits.

Sun rays l ld can also reach the totally reflecting lateral surface 6, in particular when irradiated from the side. However, they tend to have to be reflected downwards in order to subsequently be absorbed on the absorption surface 9. This is guaranteed at least if the outer surface 6 totally reflects only in the upper area.

Furthermore, a positioning and fastening possibility of the circuit board 1 is shown in FIG. 3. The housing 12 has a bore 18 in the lower region, with which the circuit board 1 is positioned and held via a position hole 19 and screw 20.

Because of the wide light emission of the SMD-LED, this optical element is shorter and therefore more conical than in FIG. 2. Here it may be necessary to pull the absorption surface 9 up to the optical axis of the lens element 3 so that part of the LED light is already shaded becomes. However, these are marginal light rays, which can only be used to a limited extent anyway, since according to optical laws they would primarily reach the upper dark area. In cross-section A-A it can be seen that the absorption surface 9 was created by flattening the lower region of the conical lens element 3. But it also extends a bit laterally up to about the middle. The flat area of the absorption surface 9 extends to the light entry surface 4, where it forms a horizontal edge 21. The position of this connecting edge 21 with respect to the optical axis is an essential determining feature for the size of the angle of incidence S of the sun rays. The position and shape of the absorption surface 9 in the remaining area of the outer surface 6 are of secondary importance. However, a flattening can be helpful in the orientation of the optical elements in the mounting holes 17 or in the manufacture of the components. In particular, the cast-on of the lens element 3 or of the housing 12 can take place on the flattened zone.

The totally reflecting zone of the outer surface 6 should of course be as large as possible in order to use as much light as possible, on the other hand the absorption surface 9 must be present wherever sun rays 11 are absorbed on the outer surface 6 have to. More precise determinations can be made via light beam tracking in a computer simulation.

Fig. 4 shows a selection of mounting holes in the matrix plate with different properties. A circular hole a allows any orientation of the optical element. Either it has to be circularly symmetrical or it has to be oriented by external measures.

The elliptical hole b allows attachment in two orientations. This makes sense if the optical element is symmetrical, but also if the orientation is easy to see.

Clear orientation is achieved through a flattened or drop-shaped hole c or d. The outline is oriented, for example, on a flattened absorption surface 9 or the fastening hole 18 according to FIG. 3.

A constant curvature of the outline is essential for a tight fit. Angular holes require gluing for fastening and sealing.

Fig. 5 shows a combination of optical elements of the same design, which are connected via a connecting surface 22 in any number, but preferably in a regular arrangement. They are pressed or glued together into the matrix plate 7. Each combination has at least one position pin 23 which projects through a suitable position hole 19 of the common circuit board 1 and holds it by means of commercially available fastening elements, such as the locking washer 24 shown. The front of the connecting surface 22 is black, like the housing 12, and has a structure 25 that absorbs maximum light. As a result, the matrix plate 7 does not require a surface coating.

6 shows a combination of optical elements by structurally combining the housings 12. Such a module, which is inherently rigid even without a matrix plate, usually has connection means at its edges, such as the tongue and groove system 26 shown, in order to form display boards of any size by stringing together in a known manner to be able to. A further advantage consists in the substantially smaller distance between the lens elements compared to the embodiment in FIG. 3 or 5. The common circuit board 1 is here by means of at least one snap hook 16 held per module and positioned by means of positioning pins 23 and positioning holes 19. Here, too, the black front of the housing block has a structure 25 that absorbs maximum light.

The application of current traffic standards requires a sun angle of 10 degrees above the horizon. But of course an even lower position of the sun can be assumed as a special security feature. Under this boundary condition, the practical design of the lens elements means that their length is considerably greater than the diameter of the exit surface. High light intensity and high efficiency always require the light source to be arranged directly behind the light entry surface.

For general displays without special security requirements, such as platform displays, a larger angle of incidence of the sun's rays can also be selected. As a result, the optics and displays can generally be made smaller.

In a further embodiment of the invention, the light source 2 can consist of several individual light sources, which are arranged together behind a lens element 3. There can even be a specially designed light entry surface for each individual light source. This allows effective distribution of very special light distributions, a higher amount of light per optical element or safety in the event of an LED failure. In particular, this makes it possible to emit different colors with just one optical element, which lowers costs or permits higher image resolution. By means of a special configuration of the lens element 3, it can be achieved that the colors have approximately the same light distribution within a restricted observation area.

The more lαiapper the light sources sit together, the less the differences in light distribution can be kept. Therefore, commercially available multiple LEDs are used, which in particular structurally combine a red, green and blue individual light source and can emit any color tone by appropriate control. This enables any image or video display in signaling technology.

Claims

claims:

1. Optical element, which is usually in an arbitrarily arranged multiplicity in essentially vertically arranged front surfaces of variable message signs

Representation of symbols or graphic information can be used, consisting of at least one controllable light source (2), usually an LED, which is on a

Board (1) can sit, a lens element (3) with light entry surface (4),

The outer surface (6) and the outlet surface (5) and preferably a housing (12) surrounding at least part of the outer surface (6), with essentially horizontal to downward inclined light radiation, the outer surface (6) having a maximum light-absorbing absorption surface (9) , characterized in that the

Absorbent surface (9) directly to the light entry (4) and exit surface (5) of the

Lens element (3) adjoins that the length of the lens element (3) is greater than its diameter and that the curvature of the exit surface (5) is designed at each surface point so that essentially all of them come from the light source (2)

Light rays (10) in a range below a defined angle S, preferably less than or equal to 10 °, with respect to the horizontal and essentially all light rays (11) incident on the absorption surface (9) from outside with an angle greater than or equal to S with respect to the horizontal be directed.

2. Optical element according to claim 1, characterized in that the entire lateral surface (6) is designed as an absorption surface (9).

3. Optical element according to claim 1, characterized in that only the lower region of the lateral surface (6) is formed as an absorption surface (9).

4. Optical element according to claim 1 or 3, characterized in that the light rays (lOd) falling on the outer surface (6) not formed as an absorption surface (9) are deflected by total reflection to the exit surface (5) and essentially all at an angle greater or equal to a fixed angle S, preferably less than or equal to 10 °, with respect to the horizontal on the exit surface (5) incident light rays (11, lld) either directly or after total reflection on the outer surface (6) on the absorption surface (9).

5. Optical element according to one of claims 1 to 4, characterized in that the entry surface (4) is arranged directly in front of the light source (2) and pre-bundles or pre-distributes the light from the light source (2) by a curvature.

6. Optical element according to one or more of claims 1 to 5, characterized in that the absorption surface (9) is formed by partial black coating or by coating the lens part (3).

7. Optical element according to one or more of claims 1 to 6, characterized in that the absorption surface (9) is formed by spraying or melting a black plastic onto the lens part (3).

8. Optical element according to one or more of claims 1 to 7, characterized in that the connecting edge (21) of the absorption surface (9) to the light entry surface (4) runs horizontally.

9. Optical element according to claim 7, characterized in that the sprayed or melted black plastic in one embodiment forms a housing (12) directly enveloping the outer surface (6) of the lens part (3).

10. Optical element according to claim 9, characterized in that the material of the housing (12) is substantially tougher, more elastic and more flexible than that of the

Lens element (3).

11. Optical element according to one or more of claims 1 to 10, characterized in that the outer casing of the housing (12) has a round, oval, egg-shaped or other continuously gel-curved cross section and the mounting hole (17) is adapted to the cross section.

12. Optical element according to one or more of claims 1 to 11, characterized in that it is tightly inserted in a mounting hole (17) of a preferably flat matrix plate (7) with a plurality of further, preferably similar and identically oriented mounting holes (17).

13. Optical element according to one or more claims 1 to 12, characterized in that the housing (12) on its outer circumference in the immediate vicinity of the exit surface (5) has a flange (13) as a stop and in the direction of the light entry surface (4) then all-round ribs (14) with a slight oversize compared to the installation hole (17).

14. Optical element according spoke 13, characterized in that after pressing in the flange (13) on the front of the matrix plate (7) abuts and the peripheral ribs (14) hold the optical element in a known manner by elastic-plastic deformation against Secure pushing out and seal the installation hole (17).

15. Optical element according to one or more of claims 1 to 14, characterized in that the housing (12) has at least one axial bore (18) on the rear side for fastening the circuit board (1) by means of suitable connecting means.

16. Optical element according to one or more of claims 1 to 15, characterized in that the housing (12) on the rear side has at least one axial positioning pin (23) which positions the circuit board (1) via a precisely fitting positioning hole (19) and also its position Attachment using commercially available fasteners (24) enables.

17. Optical element according to one or more of claims 1 to 16, characterized in that the housing (12) has at the rear at least one snap hook (16) which holds the circuit board (1).

18. Optical element according to one or more of claims 1 to 15, characterized in that the housing on the rear side has a low-play receptacle (15) for the light source (2) and at least one snap hook (16) which positions the light source (2) and holds.

19. Optical element according to one or more of claims 1 to 18, characterized in that a plurality of discrete light sources (2) are arranged behind a common lens element (3) and this has either a common or individually assigned light entry surface (4).

20. Optical element according to one or more of claims 1 to 18, characterized in that the light source (2) is designed as a structural combination of several, preferably different colors emitting and individually controllable individual light sources.

21. Optical element according to one or more of claims 1 to 20, characterized in that a plurality of optical elements are combined by connecting surfaces (22) in the region of the housing flanges (13) and are tightly pressed or glued together into a suitable hole group in the matrix plate (7).

22. Optical element according to one or more of claims 1 to 20, characterized in that a plurality of optical elements are produced in one piece

Housing (12) form a stable self-supporting structure without a matrix plate and can be combined to a larger display area using known means.

23. Optical element according to one or more of claims 1 to 22, characterized in that the outer surfaces of the housing flanges (13) and connecting surfaces (22) have a maximum light-absorbing structure (25) and color.