Projection unit, projection module and motor vehicle headlamp

Abstract

A projection unit (10) for emitting a projection light distribution (C) is provided. The projection unit (10) comprises at least one light source unit (100) arranged for emitting a primary light distribution (A), at least one reflector member (200) having a surface (210) facing the at least one light source unit (100), wherein the reflector member (200) is arranged to convert at least a portion of light of the primary light distribution (A) incident on the surface (210) into a secondary light distribution (B), wherein a reflection section (220) of the reflector member (200) directly adjoins a light trap section (230) of the reflector member (200) at least in a region of the surface (210) of the reflector member (200) in a direction of a reflector output (202), and wherein a reflectivity of the reflection section (220) is larger than a reflectivity of the light trap section (230) by a factor of several, and projection optics (300) arranged to emit the secondary light distribution (B) incident on the projection optics (300) as the projection light distribution (C) of the projection unit (10).

Description

Technical Field

[0001] This invention relates to a projection unit, a projection module, and a headlight for motor vehicles. Summary of the Invention

[0002] One aspect of the present invention relates to the subject matter of a projection unit for emitting a projected light distribution, wherein the projection unit comprises: at least one light source unit configured to emit a primary light distribution; at least one reflector member having a surface facing the at least one light source unit, wherein the reflector member is configured to convert at least a portion of the light incident on the surface of the primary light distribution into a secondary light distribution, wherein a reflective segment of the reflector member is directly adjacent to a light trap segment of the reflector member in at least a region of the surface of the reflector member along the direction of reflector output, and wherein the reflectivity of the reflective segment is several times greater than the reflectivity of the light trap segment; and a projection optics configured to emit the secondary light distribution incident on the projection optics as the projected light distribution of the projection unit.

[0003] Since the reflective and absorptive sections are directly adjacent to each other with their significantly different reflectivities, the projection optics can clearly image the boundary between the two regions onto a screen, for example, where the projection light is incident on the front of the projection unit.

[0004] Advantageously, a projection system with a reduced number of components is provided, which has beneficial effects on manufacturing costs and service life. For example, the aperture component can be omitted. Facets or adapters in the area of ​​the projection optics can also be omitted or implemented to a reduced extent. In particular, the number of interfaces between different materials is reduced by the reduced number of components, which has beneficial effects on the temperature resistance and durability of the projection module.

[0005] A favorable example is characterized by the boundary, especially the light-dark boundary, extending on the surface of the reflector component between the reflective section and the light trap section.

[0006] Advantageously, this allows for the creation of light and dark boundaries in the front area of ​​the projection unit. Especially in the field of motor vehicles, it allows for the creation of light and dark boundaries in the near-light distribution.

[0007] An advantageous example is characterized in that the top section is adjacent to the light trap section in a direction away from the direction of the reflector output, wherein the top section has a reflectivity higher than that of the light trap section and lower than that of the reflector section.

[0008] Advantageously, this allows for illumination of the area in front of the projection unit above the boundary, but with a lower illuminance than that below the boundary vertically.

[0009] An advantageous example is characterized in that the top section includes at least one of the following structures: a plurality of prisms, a surface rough portion that is raised relative to the surface in the region of the top section, and at least one surface section that is convex compared to the surrounding surface.

[0010] These measures generate radiative spread in the top area, which is accompanied by a decrease in the light intensity of the projection light distribution emitted by the projection unit.

[0011] An advantageous example is characterized in that another light trap segment of the reflector member is directly adjacent to the reflective segment of the reflector member in the direction of the reflector output, at least in the region of the reflector member’s surface facing the light source unit, and / or at least segmentally, for example, in a U-shape, surrounding the reflective segment in the direction starting from the reflector output, wherein the reflectivity of the reflective segment is several times greater than that of the other light trap segment.

[0012] Advantageously, the other light trap section can be used to image the clear boundary between the light trap section and the reflective section in the projected light distribution, thereby improving the perception for the observer.

[0013] An advantageous example is characterized in that the reflective segment has at least one convex or concave surface offset in a region of the surface, which offsets from the rest of the surface extension.

[0014] Advantageously, this allows for the adaptation of a specific region within the emitted projection light distribution, i.e., the targeted reduction or increase of light intensity there.

[0015] An advantageous example is characterized in that the substrate of the reflector component is made of a light-transparent, especially translucent, material, wherein the surface of the reflective section facing at least one light source unit is provided with a reflective coating.

[0016] Due to the transparency of the substrate, the coupling of light in the primary light distribution can be selectively configured.

[0017] A favorable example is characterized in that at least a portion of the light from the primary light distribution is coupled into the light trap section.

[0018] On the one hand, it has advantages in reducing the reflectivity of the light trap section. On the other hand, it has thermal advantages because not all energy needs to be absorbed in the surface area of ​​the light trap section.

[0019] An advantageous example is characterized in that a portion of the light from the primary light distribution can be coupled into the reflector member through the coupling surface of the transparent reflector member, wherein the coupled light can be transmitted to the coupling region through the light transmission section of the reflector member, wherein the coupling region is a portion of the surface of the reflector member facing at least one light source unit, wherein the light transmitted through the light transmission section is coupled out from the coupling region from the reflector member as part of the secondary light distribution.

[0020] Advantageously, light from at least one light source can thus be used to couple light out of the reflector member again after it has been coupled into the reflector member.

[0021] Advantageously, light can also be emitted from reflector components that are not directly illuminated by light from the primary light distribution.

[0022] One advantageous example is characterized in that the substrate of the reflector component is made of a reflective material, wherein the surface of the light trap section facing at least one light source unit is provided with a light-absorbing coating.

[0023] Advantageously, the reflector component has already been made reflective using its substrate, such as a metal alloy or a reflective plastic mixture. Therefore, the further step of coating the reflective section to produce reflective properties can be omitted.

[0024] One advantageous example is characterized in that the substrate of the reflector component is made of a light-absorbing material, wherein the surface of the reflective section facing at least one light source unit is provided with a reflective coating.

[0025] Advantageously, the light trap section can remain free and ensure the absorption of a portion of the light from the primary light distribution through the substrate. Attached Figure Description

[0026] In the attached diagram:

[0027] Figure 1 The projection unit is shown in a longitudinal sectional view, the reflector component is shown in a front view, and a measuring screen is shown on the measuring screen displaying the distribution of projected light generated by the projection unit;

[0028] Figures 2 to 6 Each shows an example of a reflector component; and

[0029] Figure 7 A motor vehicle headlight is shown. Detailed Implementation

[0030] Figure 1The projection unit 10 is shown in a longitudinal sectional view. A reflector component 200, which is part of the projection unit 10, is shown in the left-hand front view against the x-direction. A measurement screen 20, illuminated by the projection light distribution c, is shown on the right-hand side.

[0031] The projection unit 10 includes at least one light source unit 100, which is configured to emit a primary light distribution A.

[0032] At least one light source unit 100 includes, for example, one or more semiconductor light sources. Furthermore, primary optics may cover the corresponding semiconductor light source to emit a primary light distribution A from the primary optics.

[0033] At least one reflector member 200 includes a surface 210 facing at least one light source unit 100, so as to reflect a primary light distribution A from the surface 210 in at least segmental manner. Thus, at least a portion of the light incident on the surface 210 from the primary light distribution A is converted into a secondary light distribution B.

[0034] The projection optics 300, such as a projection lens or projection reflector, generates a projection light distribution C from the secondary light distribution B incident on the projection optics 300. This projection light distribution C is emitted by the projection optics 300 and therefore by the projection unit 10. The surface 210 of the reflector member 200 is imaged by the projection optics 300.

[0035] The reflective section 220 of the reflector component 200 is defined at least in a region of the surface 210 of the reflector component 200 by the light trap section 230 of the reflector component 200. The reflective section 220 is located between the reflector output 202 and the light trap section 230, through which the light of the secondary light distribution B is emitted.

[0036] The reflectivity of the reflective section 220 is several times greater than that of the optical trap section 230.

[0037] The reflectivity of the reflective section 220 is at least five times greater than that of the optical trap section 230, especially at least seven times greater, especially at least ten times greater, especially at least twenty times greater.

[0038] By using these ratios of reflectivity, the light intensity in different regions of the projected light distribution C can be set. In particular, to comply with legal regulations in road traffic, the required ratio of light intensity above the light-dark boundary to light intensity below the light-dark boundary in the projected light distribution can be maintained.

[0039] In order to provide near light, a boundary 212, especially a light-dark boundary, is provided on the surface 210 of the reflector member 200, which extends between the reflective section 220 and the light trap section 230.

[0040] In the example shown, boundary 212 segments follow the imaginary plane yx#0 and / or follows multiple corresponding, spaced-apart planes yx#0-3 in different segments. The corresponding planes yx#0-3 extend parallel to the optical axis of projection unit 10. In other words, the corresponding imaginary plane y#0-3 spans an imaginary plane parallel to the optical axis.

[0041] In particular, at the designated mounting location of the headlight, at least one plane is parallel to the road surface. In a preferred embodiment, the light-dark boundary is further defined by two planes that are parallel to the road surface at the designated mounting location and these planes have different distances from the optical axis.

[0042] In another preferred embodiment, at least a portion of the light-dark boundary is defined by a plane that is parallel to the road surface orientation at the installation location, and another portion is defined such that the second plane is oriented at an angle relative to the first plane at the installation location.

[0043] Therefore, a light-dark boundary, forming a separating segment between the reflective and non-reflective areas of light, extends between the highly reflective reflective segment 220 and the less reflective light trap segment 230. This boundary is important because it is imaged by a rear-mounted projection optics device and projects the light-dark boundary directly onto the road or the area in front of a vehicle. In practice, this light-dark boundary is used to create a clear demarcation between illuminated and unilluminated areas of the road, such as oncoming vehicles or road edges, to ensure glare-free and targeted lighting.

[0044] The boundary between light and dark areas is defined by the shape and arrangement of the reflective section 220 and the adjacent light trap section 230. The reflective section 220 ensures effective illumination of the road, while the light trap section 230 absorbs excess light that might otherwise interfere with the sharp boundary. Clearly imaging the boundary between light and dark areas of the emitted near-beam distribution as a projected light distribution C is crucial for drivers, as it achieves optimal visibility of the road without dazzling oncoming vehicles.

[0045] The optically effective surface 210 of the reflector component 200, especially the parabolic reflector, is used for the effective steering and focusing of light beams in various optical applications, such as in vehicle headlights. The reflector surface 210 is implemented, particularly in areas designed to be reflective, such that light beams emitted from the light source unit 100 at the focal point of the imaginary parabola are at least partially extended after being reflected on the reflector surface, such that these light beams are incident on the projection optics 300 and thus cause illumination in a specified direction.

[0046] The optically effective surface 210 of the reflector component 200 is characterized, for example, by a parabolic geometry, mathematically described as a paraboloid of revolution. This geometry is sized such that the focal point of the paraboloid coincides with the position of the light source or light source unit 100. The paraboloid satisfies the equation z = x^2 + y^2 / 4f, where f is the focal length of surface 210. This geometric arrangement ensures that all light beams emanating from the focal point exit in a parallel orientation relative to the optical axis through reflection on the surface.

[0047] In another example, the optically effective surface 210 of the reflector member 200 follows at least one of the following geometries in segments: an ellipsoid for focusing light between two focal points, a hyperboloid for converting incident light into a parallel beam path, or a sphere for uniform omnidirectional light distribution.

[0048] Alternatively, surface 210 can be designed as a free-form surface to enable targeted light steering, wherein a parabolic surface is preferably used as the base surface for the free-form surface. Ring geometries, for example, are suitable for asymmetric light distributions, while non-spherical surfaces provide improved control over optical aberrations.

[0049] One aspect concerns the properties of surface 210. This surface 210 has a highly reflective layer in the region of the reflective section 220, which is preferably composed of aluminum or a similar material to ensure maximum reflection efficiency. Surface 210 may also be covered by a protective layer in the region of the reflective section 220 to prevent corrosion or other environmental influences from impairing the optical properties of the reflection.

[0050] On the other hand, the optical trap section 230 is directly adjacent to the reflective section of the parabolic surface. The optical trap section 230 is designed such that it has a significantly lower reflectivity than the primary reflector according to the reflective section 220. The optical trap section 230 can be achieved through specific surface properties, such as a rougher structure or a less reflective coating. The optical trap section 230 is used to minimize scattered light or unwanted reflections that could otherwise impair optical efficiency and targeted light redirection. By selectively reducing the reflectivity in this section, better control over light distribution is achieved by absorbing excess light from the boundary region between the reflective section 220 and the optical trap section 230, or by redirecting this excess light to a region outside the main beam.

[0051] This combination of a highly reflective reflective section 220 and an adjacent light trap section 230 ensures extremely precise light redirection while effectively absorbing or deflecting undesirable beams. This optimizes the overall performance of the reflector, especially in demanding applications such as automotive lighting, where precise light distribution and minimal scattering are crucial.

[0052] A reflector surface is provided in the region of the reflector section 220. Due to its parabolic geometry and integration with the adjacent optical trap section 230, controlled and efficient light steering is ensured, while the optical trap section 230 minimizes unwanted reflections and thus improves the optical performance of the system.

[0053] A top section 240 is provided, which is adjacent to the light trap section 230 in a direction away from the reflector output 202. The top section 240 has a reflectivity that is higher than that of the light trap section 230 and lower than that of the reflector section 220.

[0054] The top section 240 may also consist of the same high-reflectivity coating used in the reflective section 220.

[0055] To reduce reflectivity, the surface from which the light for overhead lighting comes can also be constructed using a laser by introducing holes or areas into the coating, from which no light is reflected.

[0056] In this example, the top section 240 is used to illuminate the area above the light-dark boundary.

[0057] The additional optical trap section 250 is adjacent to the top section 240 in a manner that is away from the reflector output 202. The additional optical trap section 250 has a lower reflectivity than the top section 240.

[0058] The reflectivity of the reflective section 220 is twice as great as that of the top section 240, and especially five times greater.

[0059] Furthermore, another light trap segment 260 of the reflector member 200 is directly adjacent to the reflective segment 220 of the reflector member 200 in at least a region of the surface 210 of the reflector member 200 facing the light source unit 100 along the direction of the reflector output 202 and / or at least segmentally, for example, in a U-shape, surrounding the reflective segment 220 along the direction starting from the reflector output 202. The reflectivity of the reflective segment 220 is several times greater than that of the other light trap segment 260. This also provides the advantage of designing the transition between at least two of the following segments or surfaces using a suitable method: surface 210, light trap segment 260, light trap segment 230, top segment 240, and light trap segment 250. For example, the light distribution emitted by the projection unit 110 can be improved by a smooth transition of reflectivity between two of the aforementioned segments or surfaces, i.e., creating a targeted transition between different regions of the emitted light distribution.

[0060] Figure 2An example of a reflector component 200 is shown in an xz cross-sectional view, in which the optical axis is also located. In this example, the top section 240 includes a surface section 242 that is convex compared to the surrounding surface 210.

[0061] The convex portion extends in the cross-sectional view shown, in which the optical axis of the projection unit is located. The convex portion forms a protrusion that extends in an imaginary intermediate plane and then follows the reflector, which is spanned by the optical axis and the z-axis.

[0062] In embodiments not shown, the top section 240 alternatively or additionally includes at least one of the following structures: a plurality of prisms, and a surface roughness that is raised relative to the surface 210 in the region of the top section 240.

[0063] Figure 3 Another example of the reflector member 200 is shown in an xz cross-sectional view. It is specified that the reflector segment 230 has at least one convex or concave surface offset 222, 224 in a region of surface 210, which offsets from the remainder of the surface extension. Protrusions and recesses are also reasonably acceptable surface offsets.

[0064] Figure 4 An example of a reflector component is shown in an xz cross-sectional view. It is specified that the material of the substrate 204 of the reflector component 200 is light-transparent, especially translucent, wherein the surface 210 of the reflective section 220 facing at least one light source unit 100 is provided with a reflective coating 226.

[0065] Behind the transparent component, another component serves as a light trap to prevent stray light from inside the headlight. This also ensures that light or scattered light from other sources in the environment will not unintentionally couple into the light distribution B.

[0066] At least a portion of the light from the primary light distribution A is coupled into the light trap section 230. Specifically, a portion of the light from the primary light distribution A is coupled into the reflector member 200 via the coupling surface 232 of the transparent reflector member 200. The coupled light is then conducted to the coupling region 262 via the light conduction section 234 of the reflector member 200. This is achieved through multiple internal total internal reflections of the light within the substrate 204. Upon reaching the coupling region 262, the light, as part of the secondary light distribution B, is coupled out in a region of the surface 210 of the reflector member 200 facing at least one light source unit 100. In the illustrated example, the coupling region 262 is located within the light trap section 260.

[0067] For light conduction, for example, the rear side of the reflector member is provided with a structure such as a prism and / or a coating, such that the coupled light is deflected and conducted along the direction of the coupling-out section 262. The corresponding coupling-out structure is located near the coupling-out section, for example on the rear side of the reflector member 200, i.e. on the side of the reflector member 200 facing away from the surface 202, so as to couple light out of the reflector member 200.

[0068] In an example not shown, based on Figure 4 For example, the substrate 204 of the reflector component 200 is made of a light-absorbing material, wherein the surface 210 of the reflector segment 220 facing at least one light source unit 100 is provided with a reflective coating 226. Furthermore, see the section on... Figure 4 Explanation.

[0069] Figure 5 A portion of projection unit 10 is shown in another example. In this example, it is compared with... Figure 4 Compared to the previous implementation, the coupling-out region 242 is located in the top section 240 of the reflector member 200. The coupling-in region 264 is located in the optical trap section 260. Furthermore, see the section on... Figure 4 Explanation.

[0070] This example is advantageous, for instance, when the light source unit 100 emits a finite light cone 104 as a primary light distribution A.

[0071] Figure 6 A portion of the projection unit 10 is shown in another example. The material of the substrate 204 of the reflector member 200 is here implemented as reflective, wherein the surface 210 of the light trap section 230 facing at least one light source unit 100 is provided with a light-absorbing coating 236.

[0072] The absorbing sections 250 and 260 also include light-absorbing coatings 256 and 266.

[0073] In all the examples shown, the material of the substrate 204 extends at least through the reflective section 220 and the absorptive section 230, and especially through the reflective section 220, the absorptive sections 230, 250 and 260 and the top section 240.

[0074] Figure 7 A motor vehicle headlight 700 including a projection module 710 is shown. The projection module 710 includes one or more projection units 10a-b. The projection units 10a-b emit their respective projection light distributions Ca-b, which are superimposed to form a common projection light distribution D emitted by the projection module 710.

[0075] The vehicle headlight 700 includes a housing 720 in which a projection module 710 is disposed. The housing 720 has a light emission opening, which is closed by a cover plate 730. The projection module 710 is operated, for example, by means of a control device 740 for emitting light. In another example, the control device 740 is omitted and the projection module 710 is connected to a voltage supply unit.

[0076] The vehicle headlight 700 further enables the generation of a low beam distribution, which is used to fully illuminate the vehicle's path without dazzling oncoming vehicles. The low beam distribution is generated by projection units 10a-b, each of which projects its own specific light distributions Ca and Cb.

[0077] These individual distributions are superimposed to form a common light distribution D, which is optimally adapted to driving safety requirements. Targeted control of these distributions by the control unit 740 enables precise adaptation of illumination to different driving and environmental conditions, representing a significant improvement in visibility and safety in road traffic. The high beam distribution can also be narrower and illuminate a smaller area. High beams typically require higher maximum illuminance. This is usually achieved through a lower scattering width. Vertically, it extends higher, allowing it to bring light through the light-dark boundary of the low beam.

[0078] In addition to low beam distribution, high beam distribution can of course be provided using one or more projection modules. High beam distribution provides a larger range and brightness, thus providing wider illumination in dark and unlit roads. Here, the reflective section ab of the corresponding projection unit 10 is constructed such that the projected light distribution is adapted accordingly and the beam is further scattered to illuminate a larger area. In this case, the control device 740 can flexibly switch between low beam and high beam by controlling different projection units to ensure adaptive light distribution in real time.

[0079] However, the techniques described in the projection unit are not limited to use only in the field of motor vehicles. An example of an alternative application could be in the field of architectural lighting. Here, the projection unit can be used to project light distributions onto building facades or interior areas to achieve both decorative and functional purposes. The projection unit can also be used to display constantly changing patterns and colors or to selectively illuminate specific areas of a building.

[0080] Another potential application is stage lighting in theaters or live events. Here, projection units can be used to project precise light distributions onto individual performers or objects, thereby creating flexible lighting scenes that can be dynamically adapted to the performance.

[0081] Similar technologies can also be used in medical imaging. For example, projection units can be used to direct high-precision light distribution to specific areas of the body by projecting light onto them, to support surgical interventions, or to improve diagnostic imaging methods.

[0082] These examples illustrate the broad application potential of the described projection unit, which extends far beyond its use in motor vehicles.

Claims

1. A projection unit (10) for emitting a projection light distribution (C), wherein, The projection unit (10) includes: At least one light source unit (100) is configured to emit a primary light distribution (A). At least one reflector member (200) having a surface (210) facing the at least one light source unit (100), wherein the reflector member (200) is configured to convert at least a portion of the light incident on the surface (210) of the primary light distribution (A) into a secondary light distribution (B), wherein a reflective segment (220) of the reflector member (200) is directly adjacent to a light trap segment (230) of the reflector member (200) in at least a region of the surface (210) of the reflector member (200) along the direction of reflector output (202), and wherein the reflectivity of the reflective segment (220) is several times greater than the reflectivity of the light trap segment (230); and A projection optics (300) is configured to emit a secondary light distribution (B) incident on the projection optics (300) as the projection light distribution (C) of the projection unit (10).

2. The projection unit (10) according to claim 1, wherein, The boundary (212), especially the light and dark boundary, extends on the surface (210) of the reflector member (200) between the reflector section (220) and the light trap section (230).

3. The projection unit (10) according to claim 1 or 2, wherein, The top section (240) is adjacent to the light trap section (230) in a direction away from the reflector output (202), and wherein the top section (240) has a reflectivity higher than that of the light trap section (230) and lower than that of the reflector section (220).

4. The projection unit (10) according to the preceding claim, wherein, The top section (240) includes at least one of the following structures: a plurality of prisms, a surface roughness portion raised relative to the surface (210) in the region of the top section (240), and at least one surface section (242) that is convex relative to the surrounding surface (210).

5. The projection unit (10) according to any one of the preceding claims, wherein, Another light trap section (260) of the reflector member (200) is directly adjacent to the reflective section (220) of the reflector member (200) in the direction of the reflector output (202) at least in the region of the reflector member (200) facing the surface (210) of the light source unit (100) and / or surrounds the reflective section (220) at least segmentally, for example, in a U-shape, in the direction starting from the reflector output (202), and wherein the reflectivity of the reflective section (220) is several times greater than the reflectivity of the other light trap section (260).

6. The projection unit (10) according to any one of the preceding claims, wherein, The reflective section (230) has at least one convex or concave surface offset (222, 224) in the region of the surface (210), the convex or concave surface offset (222, 224) being offset from the rest of the surface extension.

7. The projection unit (10) according to any one of claims 1 to 6, wherein, The material of the substrate (204) of the reflector component (200) is light-transparent, especially translucent, and wherein the surface (210) of the reflective section (220) facing the at least one light source unit (100) is provided with a reflective coating (226).

8. The projection unit (10) according to claim 7, wherein, At least a portion of the light from the primary light distribution (A) is coupled into the light trap section (230).

9. The projection unit (10) according to any one of claims 7 and 8, wherein, A portion of the light from the primary light distribution (A) can be coupled into the reflector member (200) via the coupling surface (232) of the transparent reflector member (200), wherein the coupled light can be transmitted to the coupling region (262) via the light transmission section (234) of the reflector member (200), wherein the coupling region (262) is a portion of the surface (210) of the reflector member (200) facing the at least one light source unit (100), and wherein the light transmitted via the light transmission section (234) is coupled out from the reflector member (200) from the coupling region (262) as part of the secondary light distribution (B).

10. The projection unit (10) according to any one of claims 1 to 6, wherein, The substrate (204) of the reflector component (200) is made of a reflective material, and the surface (210) of the light trap section (230) facing the at least one light source unit (100) is provided with a light-absorbing coating (236).

11. The projection unit (10) according to any one of claims 1 to 6, wherein, The substrate (204) of the reflector component (200) is made of light-absorbing material, and wherein the surface (210) of the reflective section (220) facing the at least one light source unit (100) is provided with a reflective coating (226).

12. A projection module (710) comprising a plurality of projection units (10a-b) according to any one of the preceding claims, wherein, The projection unit (10a-b) emits a corresponding projection light distribution (Ca-b), and the corresponding projection light distribution (Ca-b) is superimposed to form a common projection light distribution (D).

13. A motor vehicle headlight (700) comprising a projection module (710) according to the preceding claim.

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