CZ2020456A3 - Lighting unit with homogeneous light output for vehicle lighting equipment - Google Patents

Abstract

The homogeneous light output lighting unit (1) for a vehicle lighting device comprises homogenization means (5, 14) having an output surface (5b, 14b) and configured to homogeneously output light emitted by at least one light source from the output surface (5b). , 14b). The lighting unit (1) further comprises a directing filter (9) provided with a diffractive structure (12), in the form of a layer, comprising a second inlet surface (9a) and an opposite second outlet surface (9b), and configured to redirect light entering the second inlet surface. (9a) to the directional filter (9) so that the output light emerging from the second output surface (9b) forms a predetermined angle with respect to the longitudinal axis of the vehicle.

Description

Lighting unit with homogeneous light output for vehicle lighting equipment

Field of technology

The invention relates to a lighting unit with a homogeneous light output for a vehicle lighting device.

State of the art

There are several ways to homogeneously illuminate the vehicle's lighting output area for some of the car's signal functions, including the use of OLED (Organic Light-emitting Diode) sources, diffuse optical filters, SurfaceLED technology, etc., but most of this area emits most light in the normal direction, i.e. the direction perpendicular to the exit surface, or the maximum luminosity shifts significantly from the longitudinal axis of the vehicle towards the normal to the exit surface. In practice, said design surface or parts thereof, for design and stylistic reasons, tend to deviate significantly from the longitudinal axis of the vehicle by their normal, up to between 30 and 60 degrees, which means that most light is emitted outside the longitudinal axis. In terms of legal requirements for the signal function, a certain minimum luminance is required for different directions, with the maximum minimum luminance being required in the direction of the longitudinal axis of the vehicle.

By default, the required luminosity in the direction of the longitudinal axis of the vehicle is achieved by selecting light sources so strong that said minimum luminosity is achieved in the direction of the longitudinal axis of the vehicle. However, this means that in the directions closer to the normal to the exit surface, greater luminosity is achieved than in the direction of the longitudinal axis, and thus wastes a lot of light output (and necessarily electrical power), because most of the light is directed into the angular space. legality and security is needed. It can then also be difficult to meet the minimum luminance in the direction of the longitudinal axis of the vehicle and at the same time not to exceed the maximum permitted luminosity in the direction close to normal to the output area for a given signal function.

Another solution used in the prior art is the use of a deflection filter with an array of refractive optical prisms. Such a filter can redirect light rays to the direction in which they strike it, with good efficiency up to 20 degrees. The deflection filter can be realized as a rigid plastic part or in the form of a flexible foil, which is applied (glued) to the outlet surface. However, this is often insufficient in practice, because the exit surfaces are often deviated by their direction from the direction of the longitudinal axis by 30 to 60 degrees, which is much more than the stated 20 degrees.

It is an object of the present invention to make more efficient use of the light emitted by the illuminated exit surface, while maintaining a homogeneous light emission, by effectively redirecting the rays with maximum luminosity to the longitudinal axis direction of the vehicle or to another predetermined direction.

The essence of the invention

The above objects of the invention are met by a lighting unit with a homogeneous light output for a vehicle lighting device, which comprises homogenizing means having an output surface and configured to homogeneously output light emitted by at least one light source from the output surface and a directional filter having a diffractive structure. made in the shape of a layer. The routing filter includes a second inlet surface and an opposite second outlet surface and is configured to redirect light entering the second inlet surface into the routing filter such that the outlet light exiting the second outlet surface forms a predetermined angle with the longitudinal axis of the vehicle.

- 1 CZ 2020 - 456 A3

According to a preferred embodiment, the homogenizing means comprises a diffusion filter in the form of a layer comprising a first inlet surface for incoming light generated by said at least one light source and its opposite first outlet surface and configured to exit homogeneous light from a first outlet surface which is also said outlet surface of the homogenizing means. , wherein said second inlet surface of the routing filter faces the first outlet surface, or said second outlet surface faces the first inlet surface. Said at least one light source is preferably an LED source.

According to another preferred embodiment, said homogenizing means further comprises collimating means configured to generate collimated light from the light emitted by said at least one light source, wherein the diffusion filter is arranged to enter the collimated light through the first input surface into the diffusion filter.

According to another preferred embodiment, the diffusion filter is located in the light path from the light source to the light output from the lighting unit between the directing filter and the light source.

According to another preferred embodiment, the directing filter is located in the light path from the light source to the light output from the lighting unit between the diffusion filter and the light source.

According to one of the preferred embodiments, the directing filter and the diffusion filter are placed in contact with each other with their surfaces on one another. The directional filter and the diffusion filter may be adhered to each other, or alternatively may be integrally joined together to form a single integral layer.

According to one of the preferred embodiments, the layer forming the routing filter is planar or curved.

According to another of the preferred embodiments, the layer forming the routing filter and the layer forming the diffusion filter are mutually parallel layers.

According to one of the preferred embodiments, the diffusion filter layer has a thickness of 0.1 mm to 4 mm.

Further, according to another preferred embodiment, the distance of the diffusion filter layer from the routing filter layer is less than or equal to 10 mm.

Said collimating means may advantageously comprise a reflector, a lens and / or a collimator.

According to another preferred embodiment, at least one of the light sources is an OLED or S-LED source comprising a third output surface for emitting homogeneous light in the normal direction to the third output surface at the light output point, where the OLED or S-LED source is also said homogenizing means the outlet surface of the homogenizing means is said third outlet surface, said second inlet surface facing the third outlet surface.

The layer forming the routing filter can be planar or curved.

According to a preferred embodiment, the layer forming the directional filter has a thickness of from 0.1 mm to 4 mm.

The layer forming the routing filter and the third output surface of the OLED or S-LED source can be parallel to each other or different.

According to one of the preferred embodiments, the routing filter layer is located on the third output surface of the OLED or S-LED source.

According to one of the preferred embodiments, the routing filter and the OLED or S-LED source are integrally connected to each other.

-2EN 2020 - 456 A3

According to one of the preferred embodiments, the second inlet surface and / or the second outlet surface of the routing filter is provided with a diffractive structure.

According to another of the preferred embodiments, the routing filter may comprise a volume diffractive grating.

According to one of the preferred embodiments, the diffractive structure has the following parameters: the height of the diffractive structure is from 500nm to 1500nm, the period is from 500nm to 1500nm, and the mean angle is inclined from 0 to 30 °.

According to one of the preferred embodiments, the diffractive directional filter is configured to redirect the light entering the second input surface into the directing filter such that the output light exiting the second output surface is parallel to the direction of the longitudinal axis of the vehicle.

Clarification of drawings

The present invention will be explained in more detail by means of exemplary embodiments thereof with reference to the accompanying drawings, in which:

Fig. 1 is a schematic cross-sectional view of a vehicle lighting device with a homogeneous light output without a deflection filter, known from the prior art,

Fig. 2 schematically shows another example of a vehicle lighting device with a homogeneous light output, comprising a deflection filter, known from the prior art, in a section through a horizontal plane,

Fig. 3 is a cross-sectional view of a deflection filter known from the prior art, used in the lighting device according to Fig. 2;

Fig. 4 shows an example of an embodiment of a directional filter according to the invention shown in cross section through a horizontal plane,

Fig. 4a detail A of Fig. 4 showing an example of an embodiment of the diffractive structure of the directional filter according to the invention of Fig. 4, shown in cross section by a horizontal plane,

Fig. 5 shows an example of an embodiment of a lighting unit with a homogeneous light output for a vehicle lighting device according to the invention in a horizontal plane section,

Fig. 5a shows another example of an embodiment of a lighting unit with a homogeneous light output according to the invention in a section in a horizontal plane, where the lighting unit comprises a collimating means,

Fig. 6 shows another example of an embodiment of a lighting unit with a homogeneous light output according to the invention using a collimating means,

Fig. 7 shows another example of an embodiment of a lighting unit with a homogeneous light output according to the invention using a collimating means,

Fig. 8 shows another example of an embodiment of a lighting unit with a homogeneous light output according to the invention, which uses an OLED or S-LED source, and

Fig. 9 shows yet another example of an embodiment of a lighting unit with a homogeneous light output according to the invention, which uses an OLED or S-LED source.

CZ 2020 - 456 A3

Examples of embodiments of the invention

Giant. 1 shows in cross section a horizontal plane yx, i.e. a horizontal plane of the vehicle which is an approximate plane of the road, an example of a lighting device with a homogeneous light output known from the prior art. Lighting device - the lamp comprises a body 2, a cover glass 13, and reflectors 3 emitting light 4 to a diffusion filter 5, the task of which is to emit homogeneous light. The diffusion on the filter can be surface (roughness or graining on the inlet and / or outlet surface), and / or volumetric (diffusion particles in the filter volume). After passing through the diffusion filter 5, the light changes direction so that the light beams 6 emerging from the diffusion filter 5 have light rays 6a with maximum luminosity, the direction of which shifts closer to normal to the exit surface of the diffusion filter 5 at the exit point. 5).

At this point, it should be emphasized that only for simplicity, the direction of the light rays 6a with maximum luminosity emanating from the first exit surface 5b of the diffusion filter 5 is drawn in the attached Figures 1, 2 and 5 directly in the normal direction n to the first exit surface 5b. In fact, in diffusion filters, the light rays 6a having the maximum luminosity emerge from the first output surface 5b with an angle to the normal significantly smaller than the angle to the normal of the collimated light 4 incident on the input surface 5a of the diffusion filter 5. In general the maximum luminosity towards normal increases as the diffuser scatter increases. The design of the lamp is often (as in the accompanying figures) such that the normal n to the diffusion filter 5 is deviated by 30 or more degrees from the direction of the longitudinal axis of the vehicle, hereinafter referred to as the "longitudinal direction x". However, for each particular signal function, the regulations set minimum luminance values for the longitudinal direction x and directions deviated from the longitudinal direction x, this value being highest for the longitudinal direction x and decreasing with the deviation from the longitudinal direction x.

In the case of the signal lamp of the prior art in Fig. 1, a light source or sources must be used to ensure that the luminosity in the longitudinal direction x is above the required minimum value, although much lower luminances would be sufficient given the prescribed values. This means wasting power or number of resources, power consumption and overall costs for both electricity and electronics. In addition, it may happen that in the direction with the maximum luminosity, ie close to the normal, the maximum permitted luminosity will be exceeded.

Giant. 2 shows an example of another lamp with a homogeneous light output, known from the prior art, in which a deflection filter 7 is used. direction near) normal n. The task of the deflection filter 7 is to deflect these light beams in a direction approaching the longitudinal direction x. For the sake of simplicity, neither the lamp body 2 nor the cover glass 13 is shown, as shown in FIG. However, deflection filters 7 can effectively deflect light by a maximum of 20 to 30 degrees, but the maximum luminosity (close to the normal direction n of the diffusion filter) in luminaires with a diffusion filter is often in a direction deviating from the longitudinal direction x by more than 30 degrees, so the deflection effect filter 7 is usually not sufficient. This is exactly the case with the solution shown. This limitation is given by the limits of geometric optics, when breaking light at large angles there are significant losses caused by fresnel or in extreme case total reflection on the prisms of the deflection filter 7. From Fig. 2 it is clear that light beam 8 with light beam 8a with maximum Due to the above-described limits, the deflection filter cannot be deflected in the direction of the longitudinal direction x In addition to the described disadvantage, deflection filters have insufficient deflection capabilities - given the essentially macroscopic dimensions of the prisms visible and disrupt even a homogeneous appearance when viewed up close.

-4EN 2020 - 456 A3

FIG. 3 shows a cross section through the horizontal plane yx of a known deflection filter 7 used in lighting devices of the type shown in FIG. 2. FIG. 3 shows a case where the normal n to the surface of the deflection filter 7 is deflected from the longitudinal direction x by an angle greater than the maximum angle α (i.e. approximately 20 degrees) by which the deflection filter 7 is still able to deflect the incident light. As can be seen, the light beam 8a with the maximum luminosity cannot be deflected by the deflection filter 7 up to the longitudinal direction x

Giant. 4 shows an example of a directional filter 9 according to the invention in cross section through the horizontal plane yx, the detail A of which is shown in FIG. 4a. In contrast to the prior art deflection filter 7, which is provided with an array 7a of macroscopic prisms, the directional filter 9 includes a surface diffractive structure 12. whose dimensions - the period p of the structure, the height h of the structure, and the mean angle ω of inclination - are microscopic. An example of the implementation of a specific preferred embodiment of the diffractive structure 12 - diffraction grating according to the invention is a diffractive structure 12 with the following parameters (designation of parameters see Fig. 4a): height h of the diffractive structure - 1000nm, periodap - 730nm The directional filter 9 with a diffractive structure 12 of the above parameters is able to deflect perpendicularly incident light with a wavelength of about 630 nm (red light) with a high efficiency by a directional angle β of up to 60 degrees. If we determine the angle between the longitudinal direction x and the normal n to the surface of the diffusion filter 5 at the point of impact of light on the diffusion filter 5, then by suitable configuration of diffractive structure parameters 12 x-direction and normal n. In addition to the above-mentioned surface grating, the diffractive structure can also be realized by a volume (Bragg) diffractive grating, eg formed by microscopic elements with a different refractive index than the surrounding filter material.

Giant. 5 shows an exemplary embodiment of a lighting unit 1 with a homogeneous light output for a vehicle lighting device according to the invention in a section through the horizontal plane yx. The lighting unit 1 comprises several light sources, which are preferably LED sources 16 located on the PCB 17, which emit light to the first input surface 5a of the diffusion filter 5, made in the shape of a thin planar or curved plate. The diffusion filter 5 must have a sufficiently strong diffusion capacity, for example a milk diffusion filter is suitable, so that there is a homogeneous light at its output. The diffusion filter 5 itself thus fulfills the role of a homogenizing means, which ensures a homogeneous light output from the homogenizing means output surface, which in this embodiment is the first diffusion filter 5 output surface 5b. surfaces 5b of the diffusion filter 5, opposite its first inlet surface 5a, project light beams 6, with each light beam 6 having the light beam 6a with the highest luminosity having a direction close to perpendicular to the first outlet surface 5b at the exit point of the first outlet surface 5b. Further, in the direction of advance of the light rays 6a, a directing filter 9 is arranged, preferably parallel to and at a distance from the diffusion filter 5. The directional filter 9 is preferably in the form of a thin planar or curved plate, and is provided with a diffractive structure / optics (not shown in Fig. 5), which can be realized in the form of a volume or surface diffractive grating, for example diffractive structure 12 described above. refer to Figures 4 and 4a. The diffractive structure redirects the light beams 6 so that the output light beams 10 emerge from the second output surface 9b, the output light beams 10a of which with the highest luminosity are directed in a predetermined direction, i.e. most often in the longitudinal direction x, i.e. the longitudinal axis direction. It should be noted here that the aim will not always be to direct the output light beams 10a exactly in the longitudinal direction x, in certain embodiments it may be desirable to redirect to another direction, for example a direction only close to the longitudinal direction x. Importantly, however, in general the directional filter 9 with a diffractive structure makes it possible to divert the incident light beams 6 with good efficiency by more than 45 degrees. Such a large deflection cannot be achieved with the deflection filter 7 described above in prior art solutions due to the limits of geometric optics. Furthermore, in the solution according to the invention, it is advantageous that the diffractive structure of the directional filter 9 is below the line of sight to the eye, so that it does not disturb the homogeneity of the light coming out of the directional filter, even on closer inspection.

-5GB 2020 - 456 A3

Giant. 5a shows another embodiment of a lighting unit 1 with a homogeneous light output for a vehicle lighting device according to the invention in a section through the horizontal plane yx. The lighting unit 1 comprises a light source (not shown) or more, a collimating means for generating a collimated light 4, which in this embodiment are reflectors 3 which emit collimated light 4 to a first input surface 5a of a diffusion filter 5 in the shape of a thin planar or curved plate. . Homogeneous light emerges from the diffusion filter 5. The above-mentioned collimating means - here the reflectors 3 and the diffusion filter 5 are thus part of the homogenizing means which ensures a homogeneous light output from the homogenizing means output surface, which in this embodiment is the first diffusion filter 5 output surface 5b. The light beams 6 are described, from the first exit surface 5b of the diffusion filter 5, opposite its first inlet surface 5a, light beams 6 project, the light beam 6a having the highest intensity in each light beam 6 having a direction close to the perpendicular to the first output surface 5b at the exit point. from the first exit surface 5b. Further, in the direction of travel of the light beams 6a, a directional filter 9 is preferably placed parallel to and at a distance from the diffusion filter 5, as in the embodiment of FIG. 5. What has been stated above for the embodiment of FIG. to the directional filter 9, its diffractive structure 12 and to the course of light passing through the directional filter 9, also applies to the embodiment of FIG. 5a.

In relation to the latter preferred embodiment of the lighting unit 1 and the further embodiments described below, it should be noted that although the preferred embodiments are shown in Figs. 5a, 6, 7 such that their collimating means are reflectors 3, the lighting unit need not include reflectors 3 and instead, it can work with other optical elements fulfilling the role of collimating means, i.e. optical elements capable of emitting collimated light rays to the diffusion filter 5, such as lenses or standard collimators.

As can be further seen from the embodiment of the invention shown in Fig. 5, the collimating means need not be included in the lighting unit 1 at all and several suitable light sources, e.g. LED sources 16 and a suitable (e.g. milk) diffusion filter 5 may be used instead to a homogeneous light output from the diffusion filter 5 has been achieved. In the light path between the light sources and the diffusion filter, other optical elements can be used, for example for directing the light.

Giant. 6 shows schematically another exemplary embodiment of a lighting unit 1 with a homogeneous light output according to the invention in a section through the horizontal plane yx. In this exemplary embodiment, the collimated light 4 first enters a directional filter 9, in the form of a thin plate, provided with a diffractive structure in one of the above-described embodiments of the diffractive structure. The parameters of the diffractive structure are chosen so that the collimated light 4 is deflected by such an angle that the output light rays 10a strike the diffusion filter 5 with the highest luminosity at an angle ensuring that the light rays 6a of the light beams 6 emerging from the diffusion filter 5 have a parallel direction. with the longitudinal direction x. Again, if the aim is for the light beams 6a with the highest luminosity to have a direction deviating from the longitudinal direction x, the diffractive parameters of the structure of the directional filter 9 are chosen so as to achieve the desired direction of the light beams 6a with the highest luminosity. Also in this embodiment, the homogenizing means comprises a collimating means in the form of reflectors 3 (especially parabolic reflectors) and a diffusion filter 5. The reflectors 3 and the diffusion filter 5 cooperate to ensure a homogeneous light output from the first output surface 5a.

Giant. 7 shows schematically another exemplary embodiment of a lighting unit 1 with a homogeneous light output according to the invention in a section through the horizontal plane yx. This exemplary embodiment differs from the embodiment described above with reference to FIG. 5 in that the routing filter 9 and the diffusion filter 5 are not located with a gap between them, but the routing filter 9 is placed, for example glued, directly on the diffusion filter 5. Principle however, the deflection of the light 4 as it passes through these layers is similar to that of the solution according to FIG. 5 and is therefore not described in more detail here. Accordingly, the solution of Fig. 7 achieves, at the same angle of incidence of light 4 on the diffusion filter 5 as the angle of incidence of light 4 in the previously described embodiment of Fig. 5, the same direction of the output light beams 10a in the longitudinal direction x as in said earlier design. However, the solution of Fig. 7 is more advantageous than the solution of Fig. 5, since here

-6GB 2020 - 456 A3 there are no fresnel losses (reflections) at the output of the diffusion filter 5 and the input to the routing filter 9.

Another possibility in relation to the solution of Fig. 7 is for the routing filter 9 to be combined with the diffusion filter 5 to form integral layers / thin plates, for example so that this plate will have a diffusion treatment (roughening) on one of its surfaces, and on the opposite surface the diffractive structure or this integral plate will have a volumetric diffusion and / or diffractive structure / lattice and on the surfaces a correspondingly diffractive and / or diffuse structure.

The diffusion filter layer (5) preferably has a thickness of 0.1 mm to 4 mm.

The distance of the diffusion filter layer (5) from the directing filter layer (9) is preferably less than or equal to 10 mm.

Giant. 8 shows schematically another exemplary embodiment of a lighting unit 1 with a homogeneous light output according to the invention in a section through the horizontal plane yx. In this exemplary embodiment, an OLED (Organic Light Emitting Diode) or S-LED (Surface LED surface source) source 14 is used as the light source. Because OLED or S-LEDs produce approximately homogeneous light at their output surface, these sources are simultaneously homogenizing agent and thus eliminates the need to use a collimator and diffusion filter to achieve homogeneous light production. However, the diffusion filter can optionally be used additionally. That is, the source 14 is itself a homogenizing means, and the exit surface of the homogenizing means is provided by the third exit surface 14b. Light beams 15 emerge from the third output surface 14b of the OLED or S-LED source 14, and at each light beam 15 the light beam 15a with the highest luminosity has a direction identical to normal n to the third output surface 14b at the exit of the third output surface 14b. Further, in the direction of advance of the light beams 15a, a directional filter 9 is preferably parallel to the surface of the OLED or S-LED source 14 and spaced therefrom. The directional filter 9 is preferably in the form of a thin planar or curved plate. / optics (not shown in Fig. 8), which can be realized in the form of a volume or surface diffractive grating, for example the diffractive structure 12 described above in connection with Figs. 4 and 4a. The diffractive structure redirects the light beams 15 so that the output light beams 10 emerge from the second output surface 9b, the output light beams 10a of which with the highest luminosity are directed in a predetermined direction, i.e. most often in the longitudinal direction x, i.e. the longitudinal axis direction. It should be noted here that the aim will not always be to direct the output light beams 10a exactly in the longitudinal direction x, in certain embodiments it may be desirable to redirect to another direction, for example a direction only close to the longitudinal direction x. Importantly, however, in general the directional filter 9 with a diffractive structure makes it possible to divert the incident light beams 6 with good efficiency by more than 45 degrees.

Giant. 9 shows schematically another exemplary embodiment of a lighting unit 1 with a homogeneous light output according to the invention in a section through the horizontal plane yx. This exemplary embodiment differs from the embodiment described above with reference to Fig. 8 in that the routing filter 9 and the OLED or S-LED source 14 are not located with a gap between them, but the routing filter 9 is located, for example glued, directly on OLED or S-LED source 14. The principle of light deflection when passing through the directional filter 9 is similar to the solution according to Fig. 8, and is therefore not described in more detail here. Accordingly, the solution of Fig. 9 achieves the same orientation of the output light beams 10a using the directional filter 9 configured in the same way as in the embodiment of Fig. 8.

Another possibility in relation to the solution of Fig. 9 is for the routing filter 9 to be combined with the light OLED or S-LED source 14 into one integral layer / thin plate.

The routing filter 9 may generally be configured such that the diffractive structure is formed on the second inlet surface 9a, the second outlet surface 9b, on both surfaces 9a, 9b, or alternatively or in addition to these possibilities inside the body of the routing filter 9 as a volumetric diffractive grating.

-7 CZ 2020 - 456 A3

The layer forming the directional filter 9 preferably has a thickness of 0.1 mm to 4 mm.

Claims (24)

PATENT CLAIMS A lighting unit (1) with a homogeneous light output for a vehicle lighting device, comprising homogenizing means (5, 14) having an output surface (5b, 14b) and configured to homogeneously output light emitted by at least one light source from the output surface (5b, 14b), characterized in that the lighting unit (1) further comprises a directional filter (9) provided with a diffractive structure (12) in the form of a layer, comprising a second inlet surface (9a) and an opposite second outlet surface (9a). 9b), and configured to redirect the light entering the second inlet surface (9a) to the directing filter (9) such that the output light exiting the second outlet surface (9b) forms a predetermined angle with the longitudinal axis of the vehicle. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to claim 1, characterized in that said homogenizing means comprises a diffusion filter (5) in the form of a layer comprising a first input surface (5a) for light input generated by said at least one light source and its opposite first exit surface (5b) and configured to output homogeneous light from the first exit surface (5b), which is also said exit surface of the homogenizing means, said second inlet surface (9a) of the directing filter (9) facing to the first outlet surface (5b), or the second outlet surface (9b) faces the first inlet surface (5a). Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to claim 2, characterized in that said at least one light source is an LED source (16). Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to claim 2 or 3, characterized in that said homogenizing means further comprises collimating means (3) configured to generate collimated light (4) from light emitted by said at least one the light source, wherein the diffusion filter (5) is arranged for the input of the collimated light (4) through the first input surface (5a) into the diffusion filter (5). Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 2 to 4, characterized in that a diffusion filter (5) is arranged on the light path from the light source to the light output from the lighting unit (1). between the directional filter (9) and the light source. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 2 to 4, characterized in that a directional filter (9) is arranged on the light path from the light source to the light output from the lighting unit (1). between the diffusion filter (5) and the light source. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 2 to 6, characterized in that the directional filter (9) and the diffusion filter (5) are arranged in contact with one another by their surfaces. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to Claim 7, characterized in that the directional filter (9) and the diffusion filter (5) are glued to one another. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to claim 7, characterized in that the directional filter (9) and the diffusion filter (5) are integrally connected to one another so as to form one integral layer. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 2 to 9, characterized in that the layer forming the directional filter (9) is planar or curved. -9EN 2020 - 456 A3 Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 2 to 10, characterized in that the layer forming the directional filter (9) and the layer forming the diffusion filter (5) are mutually parallel layers. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 2 to 11, characterized in that the diffusion filter layer (5) has a thickness of 0.1 mm to 4 mm. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 2 to 12, characterized in that the distance of the diffusion filter layer (5) from the direction filter filter layer (9) is less than or equal to 10 mm. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 4 to 13, characterized in that the collimating means comprises a reflector (3), a lens and / or a collimator. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to claim 1, characterized in that at least one of the light sources is an OLED or S-LED source (14) comprising a third output surface (14b) for emitting homogeneous light in the normal direction (n) to the third exit surface (14b) at the light exit point, where the OLED or S-LED source (14) is also said homogenizing means, so that the exit surface of the homogenizing means is said third exit surface (14b), said the second inlet surface (9a) faces the third outlet surface (14b). Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 1 to 15, characterized in that the layer forming the directional filter (9) is planar or curved. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 1 to 16, characterized in that the layer forming the directional filter (9) has a thickness of 0.1 mm to 4 mm. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 15 to 17, characterized in that the layer forming the directional filter (9) and the third output surface (14b) of the OLED or S-LED source (14) ) are parallel to each other or different. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 15 to 18, characterized in that the directional filter layer (9) is located on the third output surface (14b) of the OLED or S-LED source ( 14). Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to claim 19, characterized in that the directional filter (9) and the OLED or S-LED source (14) are integrally connected to each other. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 1 to 20, characterized in that the second inlet surface (9a) and / or the second outlet surface (9b) of the directional filter (9) is provided diffractive structure (12). Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 1 to 21, characterized in that the directional filter (9) comprises a volume diffractive grating. -10 CZ 2020 - 456 A3 Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 1 to 22, characterized in that the diffractive structure (12) has the following parameters: height (h) of the diffractive structure is from 500nm to 1500nm, period (p) is from 500nm to 1500nm, and the mean angle (ω) is from 0 to 30 °. Lighting unit (1) with a homogeneous light output for a vehicle lighting device according to any one of claims 1 to 23, characterized in that the directional filter (9) with a diffractive structure (12) is configured to redirect light entering the second input surface (9a) into the directional filter (9) so that the output light emerging from the second output surface (9b) is parallel to the direction of the longitudinal axis of the vehicle.