Light module for motor vehicle headlamps

Abstract

The present invention relates to an optical module (10) for generating a total light distribution in a motor vehicle headlight (40), the optical module (10) having a first sub-module (20a) for generating a first light distribution and a second sub-module (20b) for generating a second light distribution, wherein each of the first and second sub-modules (20a, 20b) includes at least one semiconductor light source (22a, 22b) for emitting light and an optical system (24a, 24b), the optical system (24a, 24b) having primary optical elements (26a, 26b) and secondary optical elements (28, 28a, 28b) for focusing and projecting at least a portion of the light, wherein the semiconductor light source (22a) of the first sub-module (20a) is arranged at a wavelength-dependent focal point (30a) of a first wavelength, and the semiconductor light source (22b) of the second sub-module (20b) is arranged at a wavelength-dependent focal point (30b) of a second wavelength.

Description

Technical Field

[0001] This invention relates to a light module for generating total light distribution in motor vehicle headlights. Background Technology

[0002] Light modules of the type described at the beginning are known, for example, from DE102018222333A1. The light module comprises an LED array and a two-piece lens optics. The LED array forms an active monochrome display with high brightness. Each LED corresponds to a pixel of the display and can be individually controlled at different brightness levels. A large number of light distributions can be generated through the large number of pixels and their two-dimensional distribution. These light distributions are projected into the environment through the two-piece lens optics. The light module can be integrated into a headlight so that it can generate light distributions, either alone or together with other light modules, such as low beams, high beams, partial high beams, and turn signals. A disadvantage of the described light module is that the generated image has high chromaticity. This is because the described structure cannot correct chromatic aberration errors. This problem can be solved by using achromatic or apochromatic light. However, this leads to higher cost, higher weight, more required structural space, and generally lower optical efficiency of the light module due to increased losses caused by Fresnel reflection and material absorption. Furthermore, according to the prior art, such a light module alone is insufficient to generate a full high beam distribution in a headlight.

[0003] A light module is known from US 2008 / 055896, by which brightness and / or color can be dynamically adjusted. For this purpose, the color of the light emitted by an LED, LED cluster, or LED group should be able to be varied steplessly or in stages to produce virtually any desired collimated light pattern. Correction for color difference is not described in this document. Summary of the Invention

[0004] The purpose of this invention is to provide an optical module that can eliminate the above-mentioned drawbacks.

[0005] This objective is achieved using an optical module as described in claim 1.

[0006] According to the present invention, starting from the type of optical module mentioned at the beginning, the optical module includes a first submodule for generating a first light distribution and at least one additional second submodule for generating a second light distribution, wherein the first submodule and the second submodule each include at least one semiconductor light source having a light-emitting surface for emitting light and an optical system, the optical system having a primary optical device for focusing at least a portion of the emitted light and a secondary optical device for projecting at least a portion of the focused light in the light emission direction of the optical module, wherein the total light distribution of the optical module includes the superposition of the first light distribution and the second light distribution, and the semiconductor light source of the first submodule is arranged at a wavelength-dependent focal point of a first wavelength of the optical system of the first submodule, and the semiconductor light source of the second submodule is arranged at a wavelength-dependent focal point of a second wavelength of the optical system of the second submodule, wherein the first wavelength is different from the second wavelength.

[0007] Therefore, according to the present invention, a first sub-module is designed for a first wavelength, and a second sub-module is designed for a second wavelength. The light distributions of the first and second sub-modules each include significant color errors, wherein the color error specifically refers to the deviation of the light color from a certain white point. By superimposing the light distributions of the first and second sub-modules, the color errors in the total light distribution of the optical module cancel each other out.

[0008] Since the first submodule is designed for the first wavelength, it images the beam of that wavelength clearly. Because the optical system includes neither achromatic nor apochromatic components, imaging of other wavelengths, such as the second wavelength, is not optimal. Therefore, the first light distribution includes color errors, especially in edge regions. Color error is understood as the deviation of the light color from the white point. For example, at the boundary between light and dark areas, the light distribution includes a color fringing generated by the second wavelength beam in areas that should appear dark. At the boundary between light and dark areas, in areas that should appear bright, the proportion of the second wavelength beam is somewhat too small, thus the first wavelength beam determines the light color in an enhanced manner. This effect is also called chromatic aberration. Chromatic aberration is not corrected by the first optical system. Therefore, as already mentioned, achromatic or apochromatic components would be necessary, resulting in the replacement of secondary optics with achromatic or apochromatic components. This, in turn, increases the number of lenses in the optical system. This will be associated with higher cost, larger required structural space, greater weight, and potentially lower optical efficiency.

[0009] Since the second submodule is designed for the second wavelength, it images the second wavelength beam clearly. Because the optical system includes neither achromatic nor apochromatic elements, imaging of other wavelengths, such as the first wavelength beam, is not optimal. Therefore, the second light distribution includes color errors, especially in edge regions. For example, at the light-dark boundary, in areas that should appear dark, the light distribution includes a color fringing generated by the first wavelength beam. At the light-dark boundary, in areas that should appear bright, the proportion of the first wavelength beam is somewhat too small, thus the second wavelength beam determines the color of the light in an enhanced manner.

[0010] The color error of the first light distribution in the first submodule and the second light distribution in the second submodule can be corrected by superimposing the two light distributions. Therefore, by properly designing the first and second submodules, the chromaticity of the total light distribution can be significantly reduced.

[0011] The total light distribution generated by the optical module does not include hard white contrast at the boundaries between light and dark areas. In the case of motor vehicle headlights, hard white contrast is generally not needed. Typically, even extra effort is made to reduce contrast at the boundaries between light and dark areas, for example, through so-called microstructuring or frosting of the lens surface. Such measures are not required in the optical module according to the invention.

[0012] In summary, a sufficiently color-neutral total light distribution can be generated by appropriately designing the sub-modules of the optical module, while avoiding harsh white contrasts at the boundaries between light and dark areas. This eliminates the need for achromatic or apochromatic lenses, as well as additional microstructures or frosting on the lens surfaces. Consequently, cost, weight, and structural space are advantageously minimized. Simultaneously, optical efficiency can be advantageously improved through appropriate material selection and design, as fewer lenses or lens surfaces are required, resulting in less absorption and less loss due to Fresnel reflection.

[0013] According to a preferred embodiment, the first light distribution of the first submodule and the second light distribution of the second submodule are at least partially, and especially mostly, superimposed. It may also prove advantageous that the illumination areas of the first and second submodules are the same, so that at least the first and second light distributions are completely superimposed.

[0014] According to a preferred embodiment, the semiconductor light source of the first submodule and / or the semiconductor light source of the second submodule includes at least one, and in particular multiple, light-emitting diodes, i.e., LEDs. The LEDs can be stacked in a matrix or arranged side-by-side, thereby forming an LED array. The LEDs of the semiconductor light source can advantageously be controlled individually, in groups, or all together.

[0015] According to another preferred embodiment, the numerical aperture of the optical system of the first and / or second sub-module is at least 0.5, and in particular at least 0.65.

[0016] Advantageously, it can be specified that the secondary optics of the first submodule and the secondary optics of the second submodule are constructed as a single piece. This reduces the number of components and thus reduces the tolerances to be maintained in terms of component positioning and cost. Furthermore, the particularly single-piece cylindrical shape of the light-emitting surface can have a beneficial impact on the aesthetic appearance of the optical module.

[0017] Advantageously, it can be specified that the secondary optics of the first submodule and the secondary optics of the second submodule are configured as deformable lenses.

[0018] In an improved embodiment of the present invention, it can be found advantageous that at least one light incident surface of the deformable lens is configured as a cylindrical face segment having a horizontal axis of rotation, and at least one light exiting surface of the deformable lens is configured as a cylindrical face segment having a vertical axis of rotation.

[0019] Advantageously, it can be specified that the first submodule and / or the second submodule includes an aperture.

[0020] It can be proven advantageous that the aperture of the first and second sub-modules is constructed as a single piece.

[0021] According to another preferred embodiment, the optical module includes a third sub-module for generating a third light distribution. The third sub-module has at least one semiconductor light source having a light-emitting surface for emitting light and an optical system. The optical system has a primary optical device for focusing at least a portion of the emitted light and a secondary optical device for projecting at least a portion of the focused light in the light-emitting direction of the optical module. The total light distribution of the optical module includes a superposition of the third light distribution. The semiconductor light source is arranged at a wavelength-dependent focal point of a third wavelength of the optical system of the third sub-module. The third wavelength is different from the first wavelength and the second wavelength.

[0022] The design options described with reference to the first and / or second submodules can also be applied to the third submodule. Furthermore, the optical module may include additional submodules, specifically designed for other wavelengths.

[0023] Advantageously, it can be specified that the first wavelength is about 500 nm and / or the second wavelength is about 570 nm and / or the third wavelength is about 470 nm.

[0024] Another embodiment includes a motor vehicle headlight comprising at least one light module, wherein the light module is configured according to the above embodiment. Attached Figure Description

[0025] Advantageous improvements and further preferred embodiments of the invention can be obtained from the dependent claims, the following description of the drawings, and the related figures. In the drawings: Figure 1 A perspective view is shown of an optical module according to a first embodiment of the present invention; Figure 2 Shown in top view Figure 1 optical modules; Figure 3a and Figure 3b Each showed Figure 1 and Figure 2 Spot-Diagram of the first and second optical systems of the optical module. Figure 4 A perspective view is shown of an optical module according to a second embodiment of the present invention; Figure 5 Shown in top view Figure 4 optical modules; Figure 6 Shown in side view Figure 4 and Figure 5 optical modules; Figure 7a and Figure 7b It shows Figure 4 , Figure 5 and Figure 6 Different implementations of secondary optical devices in optical modules; and Figure 8 A motor vehicle headlight having a light module according to the invention is shown. Detailed Implementation

[0026] Figure 1 and Figure 2 The light module, generally identified by reference numeral 10, is shown. The light module 10 is used in a motor vehicle headlight to generate a predetermined total light distribution on the road surface in front of the vehicle in the light emission direction.

[0027] The optical module includes a first submodule 20a and a second submodule 20b. The first submodule 20a includes a semiconductor light source 22a. The second submodule 20b includes a semiconductor light source 22b. According to the illustrated embodiment, the semiconductor light sources 22a and 22b include a plurality of light-emitting diodes, i.e., LEDs. The LEDs can be stacked in a matrix or arranged side-by-side, thereby forming an LED array. The LEDs of the semiconductor light sources 22a and 22b can advantageously be controlled individually, in groups, or all together.

[0028] Furthermore, the first submodule 20a and the second submodule 20b each include optical systems 24a and 24b, each having primary optical devices 26a and 26b for focusing at least a portion of the light emitted from the semiconductor light sources 22a and 22b, and each having secondary optical devices 28a and 28b for projecting at least a portion of the focused light onto the light emission direction 12 of the optical module 10 as a first light distribution and a second light distribution.

[0029] The semiconductor light source 22a of the first submodule is arranged at the wavelength-dependent focal point 30a of the optical system 24a of the first submodule 20a, and the semiconductor light source 22b of the second submodule 20b is arranged at the wavelength-dependent focal point 30b of the optical system 24b of the second submodule 20b. The first wavelength and the second wavelength are different from each other.

[0030] By arranging semiconductor light source 22a at the focal point 30a of optical system 24a for a first wavelength, and by arranging semiconductor light source 22b at the focal point 30b of optical system 24b for a second wavelength, a first submodule 20a is designed for the first wavelength, and a second submodule is designed for the second wavelength. "Design" here is understood to mean that the optical system 24a of the first submodule 20a images the semiconductor light source 22a of the first wavelength as clearly as possible, and that the optical system 24b of the second submodule 20b images the semiconductor light source 22b of the second wavelength as clearly as possible.

[0031] Figure 3a and Figure 3b Each of the first and second submodules 20a and 20b is shown as a so-called dot plot for a central object point, i.e., for a point located at the intersection of the plane of the respective semiconductor light source 22a and 22b and the optical axis of the respective optical system 24a and 24b. In the dot plot, the incident point starting from the central object point is displayed in the image plane.

[0032] exist Figure 3aThe diagram shows a dot plot of the first submodule 20a. A beam of the first wavelength is incident on the central region of the plot, while light of the second wavelength is scattered around the central region, for example, with a radius of approximately 0.2 degrees. The incident point of the first wavelength beam is marked with a cross. The incident point of the second wavelength beam is marked with a square. Since the first submodule 20a is designed for the first wavelength, the radius of the central region where the first wavelength beam is incident is the smallest. Because the optical system 24a does not include either achromatic or apochromatic light, the imaging of other wavelengths, such as the second wavelength beam, is not optimal. Therefore, the light distribution generated by the first submodule 20a may include color errors, especially in the edge regions of the light distribution. Color error is understood as the deviation of the light color from the white point. For example, the light distribution at the light-dark boundary includes a color fringing generated by the second wavelength beam in areas that should appear dark. At the light-dark boundary in areas that should appear bright, the proportion of the second wavelength beam is somewhat too small, thus the first wavelength beam determines the light color in an enhanced manner. This effect is also called chromatic aberration. Chromatic aberration is not corrected by the first optical system 24a. Therefore, as already mentioned, achromatic or apochromatic asymmetry will be necessary. This will increase the number of components, especially lenses, in the optical system 24a, and thus lead to higher costs, larger required structural space, greater weight, and potentially lower optical efficiency.

[0033] exist Figure 3b The diagram shows a dot plot of the second submodule 20b. A beam of the second wavelength is incident on the central region, while a beam of the first wavelength is scattered to different points around the central region, for example, with a radius of approximately 0.2 degrees. The incident points of the first wavelength beam are marked with crosses. The incident points of the second wavelength beam are marked with squares. Because the second submodule 20b is designed for the second wavelength, the radius of the central region where the second wavelength beam is incident is the smallest. Since the optical system 24b also does not include achromatic or apochromatic light, imaging of other wavelengths, such as the first wavelength beam, is not optimal. Therefore, the light distribution generated by the second submodule 20b may include color errors, especially in the edge regions of the light distribution. For example, the light distribution at the light-dark boundary includes a color fringing generated by the first wavelength beam in areas that should appear dark. At the light-dark boundary in areas that should appear bright, the proportion of the first wavelength beam is somewhat too small, so the second wavelength light here determines the color in an enhanced manner. Chromatic aberration is also not corrected by the second optical system 24b.

[0034] Color errors in the first light distribution of the first submodule 20a and the second light distribution of the second submodule 20b can be corrected by superimposing the two light distributions. Advantageously, the first light distribution of the first submodule 20a and the second light distribution of the second submodule 20b are at least partially, and especially mostly, superimposed. It can also be advantageous that the illumination areas of the first submodule and the second submodules 20a, 20b are the same, so that at least the first light distribution and the second light distribution are completely superimposed.

[0035] The first wavelength is, for example, 500 nm, and the second wavelength is, for example, 570 nm. In this case, the first light distribution includes a blue rim in the darker areas at the light-dark boundary and a warm white to yellow light color in the brighter areas at the light-dark boundary. The second light distribution includes a yellow rim in the darker areas at the light-dark boundary and a cool white to blue light color in the brighter areas at the light-dark boundary. By superimposing the two light distributions, the yellow and blue rims are superimposed in the darker areas at the light-dark boundary, and the cool white to blue light color and the warm white to yellow light color are superimposed in the brighter areas, so that the total light distribution includes white light color.

[0036] Therefore, by properly designing the first submodule and the second submodules 20a and 20b, the chromaticity of the total light distribution of the optical module 10 can be significantly reduced.

[0037] The total light distribution generated by the light module 10 does not include any hard white contrast at the boundaries between light and dark areas. In the case of motor vehicle headlights, hard white contrast is generally not needed. Typically, even extra effort is made to reduce contrast at the boundaries between light and dark areas, for example, through so-called microstructuring or frosting of the lens surface. Such measures are not required in the light module 10 according to the invention.

[0038] In summary, a sufficiently color-neutral total light distribution can be generated by appropriately designing the sub-modules 20a and 20b of the optical module 10, while avoiding harsh white contrasts at the boundaries between light and dark areas. Here, achromatic or apochromatic lenses and additional microstructures or frosting of the lens surfaces can be eliminated. Therefore, cost, weight, and structural space are advantageously minimized. Simultaneously, optical efficiency can be advantageously improved through appropriate material selection and design, because fewer lenses or lens surfaces are required, resulting in less absorption and less loss due to Fresnel reflection.

[0039] exist Figure 2The diagram also shows the beam paths 32a and 32b of the first and second sub-modules 20a and 20b for the corresponding wavelengths targeted by the design sub-modules 20a and 20b. The beam paths 32a and 32b each originate from the respective centers of the corresponding semiconductor light sources 22a and 22b located at the focal points 30a and 30b and are captured and imaged by the optical systems 24a and 24b.

[0040] The illustration of the side-by-side arrangement of beam paths here is merely illustrative. Advantageously, beam paths 32a and 32b are advantageously superimposed to form the overall light distribution of optical module 10.

[0041] The light beams emitted from semiconductor light sources 22a and 22b have high divergence. Typically, semiconductor light sources 22a and 22b each emit into the entire half-space. The more of these light beams captured and imaged by optical systems 24a and 24b, the larger the so-called numerical aperture of optical systems 24a and 24b. The numerical aperture is proportional to the sine of the angle. If semiconductor light sources 22a and 22b are Lambertian radiators, the optical efficiency of optical systems 24a and 24b is again proportional to the square of the numerical aperture. Therefore, the efficiency is proportional to the square of the sine of the angle. Thus, it is highly advantageous for the efficiency of the optical module 10 to have as high a numerical aperture as possible for optical systems 24a and 24b. Advantageously, the numerical aperture of optical systems 24a and 24b is at least 0.5, and especially 0.65.

[0042] Figure 4 , Figure 5 and Figure 6 A different illustration of another embodiment of the optical module 10 is shown.

[0043] According to the illustrated embodiment, optical module 10 includes an additional submodule 20c. In principle, submodule 20c is constructed similarly to the already described submodules 20a and 20b and is advantageously designed here for a third wavelength. Here, the third wavelength differs from the first and second wavelengths.

[0044] also, Figure 4 , Figure 5 and Figure 6 The optical module includes an aperture 34. According to the illustrated embodiment, the aperture 34 is configured as a single piece for the three sub-modules 20a, 20b, and 20c. However, alternatively, it is also conceivable that each sub-module 20a, 20b, and 20c includes a separate aperture.

[0045] according to Figure 4 , Figure 5 and Figure 6In the illustrated embodiment, the secondary optical components 28a, 28b, and 28c of the optical systems 24a, 24b, and 24c of submodules 20a, 20b, and 20c are configured as a single-piece secondary optical component 28. This single-piece secondary optical component 28 is further configured as a morphing lens. This demonstrates... Figure 7a and Figure 7b middle.

[0046] Figure 7a The deformable lens 28 is shown from the light incident side, and Figure 7b The deformable lens 28 is shown from the light-emitting side. According to the illustrated embodiment, each of the light-incident surfaces 36a, 36b, and 36c includes a cylindrical face segment having a vertical axis of rotation. The light-emitting surface 38 includes a cylindrical face segment having a horizontal axis of rotation, particularly perpendicular to the light-emitting direction 12.

[0047] The light incident surfaces 36a, 36b, and 36c are designed in such a way that the incident beam is focused within the horizontal plane. (See [reference needed]). Figure 5 The light exit surface 38 is advantageously designed such that the emitted beam is focused in a vertical plane, see [reference needed]. Figure 6 .

[0048] The one-piece secondary optics 28 reduces the number of required components and thus reduces the tolerances to be maintained in terms of positioning and cost. In addition, the particularly one-piece cylindrical shape of the light emitting surface 38 can have a favorable effect on the aesthetic appearance of the optical module 10.

[0049] at last, Figure 8 A motor vehicle headlight 40 is shown. The headlight 40 includes a housing 42, for example, made of plastic. The housing 42 has a light emission opening 44 in the light emission direction 12, which is closed by a transparent cover plate 46. A light module 10 according to the invention is arranged inside the housing 42. The light module 10 is used to generate any generated driving light distribution of the motor vehicle headlight or a part thereof, such as low beam headlights, high beam headlights, adaptive driving lights (city lights, rural lights, highway lights, partial high beam headlights, marker lights), fog lights, etc. Together with the headlight module 10, other light modules for generating any driving light distribution or a part thereof, or light modules for realizing any light function (e.g., hazard lights, position lights, parking lights, daytime running lights, parking lights, reversing lights, brake lights, etc.) may also be arranged in the housing 42.

Claims

1. An optical module (10) for generating total light distribution in a motor vehicle headlight (40), characterized in that, The optical module (10) includes a first sub-module (20a) for generating a first light distribution and at least one additional second sub-module (20b) for generating a second light distribution. Each of the first and second sub-modules includes at least one semiconductor light source and an optical system having a light-emitting surface for emitting light. The optical system has primary optical devices (26a, 26b) for focusing at least a portion of the emitted light and secondary optical devices for projecting at least a portion of the focused light onto the light emission direction (12) of the optical module (10). The total light distribution of the optical module (10) includes a superposition of the first and second light distributions. The semiconductor light source (22a) of the first sub-module (20a) is arranged at a wavelength-dependent focal point (30a) of a first wavelength of the optical system (24a) of the first sub-module (20a). A submodule (20a) is designed for the first wavelength and clearly images the beam of the first wavelength, and the semiconductor light source (22b) of the second submodule (20b) is arranged at the wavelength-dependent focal point (30b) of the optical system (24b) of the second submodule (20b), the second submodule (20b) is designed for the second wavelength and clearly images the beam of the second wavelength, wherein the first wavelength is different from the second wavelength, such that the color error caused by the beam of the second wavelength in the first light distribution of the first submodule (20a) and the color error caused by the beam of the first wavelength in the second light distribution are canceled out by the superposition of the first light distribution and the second light distribution in the total light distribution of the optical module (10).

2. The optical module (10) according to claim 1, characterized in that, The first light distribution of the first submodule (20a) and the second light distribution of the second submodule (20b) are at least partially superimposed.

3. The optical module (10) according to claim 1, characterized in that, The semiconductor light source (22a) of the first submodule (20a) and / or the semiconductor light source (22b) of the second submodule (20b) include at least one light-emitting diode.

4. The optical module (10) according to claim 1, characterized in that, The numerical aperture of the optical system of the first submodule (20a) and / or the second submodule (20b) is at least 0.

5.

5. The optical module (10) according to claim 1, characterized in that, The secondary optical device of the first submodule (20a) and the secondary optical device of the second submodule (20a) are formed in one piece.

6. The optical module (10) according to claim 1, characterized in that, The secondary optical device of the first submodule (20a) and / or the secondary optical device of the second submodule (20b) are configured as a deformable lens (28).

7. The optical module (10) according to claim 6, characterized in that, At least one light incident surface (36a, 36b, 36c) of the deformable lens (28) is configured as a cylindrical face segment with a horizontal axis of rotation, and at least one light exit surface (38) of the deformable lens (28) is configured as a cylindrical face segment with a vertical axis of rotation.

8. The optical module (10) according to claim 1, characterized in that, The first submodule (20a) and / or the second submodule (20b) include an aperture (34).

9. The optical module (10) according to claim 8, characterized in that, The aperture (23) of the first submodule (20a) and the second submodule (20b) is a single piece.

10. The optical module (10) according to claim 1, characterized in that, The optical module (10) includes a third sub-module (20c) for generating a third light distribution. The third sub-module (20c) has at least one semiconductor light source (22c) having a light-emitting surface for emitting light and an optical system (24c). The optical system (24c) has a primary optical device (26c) for focusing at least a portion of the emitted light and a secondary optical device (28c) for projecting at least a portion of the focused light onto the light emission direction (12) of the optical module (10). The total light distribution of the optical module (10) includes a superposition of the third light distribution. The semiconductor light source (22c) is arranged at a wavelength-dependent focal point (30c) of the third wavelength of the optical system (24c) of the third sub-module (20c). The third wavelength is different from the first wavelength and / or the second wavelength.

11. The optical module (10) according to claim 10, characterized in that, The first wavelength is 500 nm and / or the second wavelength is 570 nm and / or the third wavelength is 470 nm.

12. A headlight for a motor vehicle, comprising at least one optical module (10), characterized in that, The optical module (10) is configured according to at least one of claims 1 to 11.

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