Headlamp for motor vehicle

Abstract

The invention relates to a headlamp for a motor vehicle, comprising: at least one light source (1); an optical device having a plurality of optical components, which is provided for shaping and projecting the light (6) emitted from the at least one light source (1) into the exterior of the motor vehicle in such a way that a low beam distribution (22) of the headlight having a light / dark boundary (19) is generated; at least one refractive structure (14) which is arranged on at least one of the optical components and has a plurality of structural elements (15), the at least one structure (14) being provided for influencing a gradient of a light intensity of a low beam distribution (22) in the region of a light / dark boundary (19), the structural element (15) of the at least one refractive structure has a width (b) between 0.5 mm and 1.0 mm.

Description

Technical Field

[0001] The invention relates to a headlamp for a motor vehicle according to the preamble of claim 1. The invention also relates to a method for producing an optical component of a headlamp according to the preamble of claim 14. Background Art

[0002] For a lighting device for a motor vehicle configured as a headlamp, edges may appear in the light distribution projected into the exterior space of the vehicle. These can be, for example, the light-dark boundary of a low-beam distribution or the vertical edge of a matrix high beam. When the light-dark boundary (Hell-Dunkel-Grenze, HDG) is imaged into the exterior space of a motor vehicle, the gradient of the light intensity in the region of the light-dark boundary must be within a predetermined magnitude in accordance with legal provisions (which are known as the abbreviation AK-31). This corresponds to a local softening (Aufweichen) of the light-dark boundary of the low-beam distribution at a horizontal angle of -2.5°. The technical difficulty is that at other horizontal angles, the light-dark boundary is not allowed to soften or is only allowed to soften almost imperceptibly. Therefore, in particular at a horizontal angle of 0°, the glare value is not allowed to be exceeded to avoid affecting oncoming vehicles. Another conflicting technical requirement is that the activation value of the headlamp, such as the maximum intensity, is only allowed to drop very slightly. However, the softening of the light-dark boundary is generally accompanied by a reduction in these values.

[0003] A headlamp of the aforementioned type is known from DE 10 2018 131 556 A1. In the headlamp described therein, the projection lens of the headlamp is provided with a microstructure. This microstructure is used to locally soften the light-dark boundary. The individual structural elements of the microstructure each have a width in the range of significantly less than 100 μm. The realization of such a microstructure in an industrial batch process brings difficulties with respect to the molding of microscopically small structures, brings risks with respect to reproducibility and increases the complexity of batch production. In addition, the introduction of the microstructure is an additional process step. Summary of the invention

[0004] The problem underlying the invention is to create a headlamp of the type mentioned at the outset which can be produced more easily and more cost-effectively. In addition, a method for producing an optical component of the headlamp should be specified.

[0005] This is achieved according to the invention by a headlamp of the type mentioned in the introduction having the features of claim 1 and by a method of the type mentioned in the introduction having the features of claim 14. The dependent claims relate to preferred embodiments of the invention.

[0006] According to claim 1, the structural element of the at least one refractive structure has a width between 0.5 mm and 1.0 mm. In particular, the height of the structural element can be between 0.1 mm and 1.0 mm, preferably between 0.3 mm and 0.7 mm, for example about 0.5 mm. Therefore, compared with the prior art, the refractive structure is not a microscopic refractive structure, but a macroscopic refractive structure. Macroscopic structures are easier to give, easier to transmit to the manufacturer of the structural element in terms of data technology, and in particular significantly easier to manufacture. Due to the selected mechanical dimensions of the structural element, no diffraction effects or only very small diffraction effects occur on the refractive structure. This allows the effect of the optical component to be fully determined and predicted in terms of light optics. Color effects due to wave optics phenomena, such as they can occur on very small structures, are at least reduced or even completely eliminated.

[0007] It can be provided that at least one of the structural elements is configured as an annular or partially annular, and in particular, a plurality of, preferably all, of the structural elements of the refractive structure are configured as annular or partially annular. Therefore, the structural element can deflect a portion of the light passing through the structural element in a desired direction like a Fresnel lens.

[0008] There is the following feasibility: the structural elements configured as annular or partially annular are arranged coaxially or concentrically with each other. It can be provided that the diameter of the first structural element in the structural element configured as annular or partially annular is smaller than the diameter of the second structural element in the structural element configured as annular or partially annular.

[0009] There is a possibility that at least one of the structural elements is designed as a partially annular structure, so that the structural element extends over less than 360° in the circumferential direction, in particular only over a sector of a circle. As a result, only a small part of the optical component on which the refractive structure is arranged is modified, so that the optical component can more effectively realize its actual function.

[0010] It may be provided that at least one of the optical components is designed as a lens, in particular as an aspherical lens, into which the refractive structure is integrated.

[0011] Alternatively, it can be provided that at least one of the optical components is configured as a lens having a Fresnel structure, into which the refractive structure is integrated. Here, the Fresnel structure can include annular steps, each of which has a useful side surface and an interference side surface, the useful side surface being a region of the step that is provided for light to pass through the region, and the interference side surface being a region of the step that is not provided for light to pass through the region, the useful side surface of the Fresnel structure enclosing an angle of attack with a plane perpendicular to the optical axis of the lens, the angle of attack can, for example, have a magnitude between 0.1° and 5.0°.

[0012] There is a possibility that the integration of the refractive structure into the Fresnel structure causes a partial change in the angle of attack of the useful side of the Fresnel structure, in particular, the angle of attack of the interfering side of the Fresnel structure is not changed due to the integration of the refractive structure into the Fresnel structure. By slightly changing the angle of attack of some useful side, the refractive caustics (diacustik) of the light passing through the optical component provided with the structure in the spatial angle range around the light-dark boundary can be appropriately widened to appropriately soften the light-dark boundary.

[0013] It can be provided that the headlight comprises a primary optics and a secondary optics, in particular the primary optics being provided for shaping the light originating from the at least one light source so as to produce an extended light distribution, and the secondary optics being provided for converting the extended light distribution produced by the primary optics into a light distribution corresponding to the low beam distribution of the headlight. The secondary optics can here have a projection lens.

[0014] There is the possibility that the refractive structure is arranged on the projection lens of the secondary optics. In this case, the refractive structure can be integrated into the coupling-in side or coupling-out side of the projection lens of the secondary optics.

[0015] According to claim 14, the optical component is produced from plastic by injection molding, during which the refractive structure is also produced. In this way, an additional work step for introducing the refractive structure into the optical component is omitted.

[0016] It can be provided that for the injection molding, the construction data of the optical component to be manufactured are used, and the construction data are generated in an iterative method with respect to the shape and arrangement structure of the structural elements of the refractive structure, in particular, in an iterative step, the shape and / or arrangement structure of at least one of the structural elements is changed in the construction data, and in a subsequent iterative step, it is determined in a simulation whether the optical component manufactured according to these construction data meets the legal provisions for the low beam distribution, in particular the legal provisions in the area of ​​the light-dark boundary. Here, it can be attempted to keep not only the influence of the refractive structure in the spatial angle range to be considered but also the geometrical proportion of the refractive structure on the surface of the optical component as small as possible. In particular, this iterative method ultimately gives a softening function for the discrete attack angle of the useful side of the refractive structure, which achieves the desired effect. This softening function can be realized as a refractive structure and implemented in the optical component. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be described in more detail below with the aid of the accompanying drawings.

[0018] Figure 1 shows a schematic side view of a headlamp according to the invention, together with exemplary drawn light rays;

[0019] Figure 2 Show according to Figure 1 A perspective view of a first embodiment of a headlight projection lens, wherein the projection lens is provided with a Fresnel structure;

[0020] Figure 3 Show according to Figure 2 The projection lens and Figure 2 corresponding views, in which the regions provided with the refractive structures are marked;

[0021] Figure 4 A perspective view showing a second embodiment of a projection lens for a headlamp according to the invention, wherein the projection lens is provided with a Fresnel structure;

[0022] Figure 5a Show according to Figure 2 A schematic cross-sectional view of a portion of a Fresnel structure of a projection lens, wherein no refractive structure for softening the light-dark boundary is integrated;

[0023] Figure 5b Show according to Figure 3 A schematic cross-sectional view of a portion of a Fresnel structure of a projection lens, in which a refractive structure for softening the light-dark boundary is integrated;

[0024] Figure 6 A perspective view showing a projection lens of a headlamp according to the prior art;

[0025] Figure 7 A perspective view showing a third embodiment of a projection lens for a headlamp according to the present invention;

[0026] Figure 8a shows the light distribution produced by a headlamp without a refractive structure for softening the light-dark boundary;

[0027] Figure 8b Show according to Figure 8a A graph showing a change in the luminous intensity of the light distribution in the vertical direction in the light-dark boundary region;

[0028] Figure 9a Shown by Figure 1 The light distribution produced by the headlights;

[0029] Figure 9b Show according to Figure 9a FIG. 4 is a graph showing the change in the vertical direction of the luminous intensity of the light distribution in the light-dark boundary area. DETAILED DESCRIPTION

[0030] In the figures, identical parts having the same function are provided with the same reference symbols.

[0031] Figure 1 The illustrated embodiment of the headlight according to the invention comprises two light sources 1, which are only schematically illustrated, a primary optics 2 having two optical components 3 connected to one another, and a secondary optics 4, which in particular has only one optical component, which is designed as a projection lens 5. It is entirely possible for the primary optics 2 to consist of only one component 3 or of more than two components 3. It is also possible for the secondary optics 4 to consist of more than one component.

[0032] The primary lens system 2 is provided to shape the light 6 originating from the light source 1 so as to generate an extended light distribution. The secondary lens system 4 is also provided to convert the extended light distribution generated by the primary lens system 2 into a light distribution corresponding to the low beam distribution of the headlight, which has a light-dark boundary.

[0033] The projection lens 5 has an incoupling side 7 for the light 6 originating from the primary optics 2 and an outcoupling side 8 from which the light 6 can exit. The projection lens 5 is designed as a lens with a Fresnel structure 9, wherein the Fresnel structure 9 is arranged on the outcoupling side 8 of the projection lens 5 (see Figure 1 and Figure 2 ).

[0034] exist Figures 1 to 3 In the exemplary embodiment shown, the coupling-in side 7 is designed to be flat. Figure 4An alternative embodiment of a projection lens 5 is shown, in which the Fresnel structure 9 is arranged on a curved base body.

[0035] The Fresnel structure 9 comprises an annular step 10, each of which has a useful side surface 11 and an interfering side surface 12 (see Figure 5a ). Here, the useful side surface 11 is the area of ​​the step 10 that is provided for light to pass through, while the interfering side surface 12 is the area of ​​the step 10 that is not provided for light to pass through. Here, the useful side surface 11 of the Fresnel structure 9 encloses an angle of attack α with a plane perpendicular to the optical axis 13 of the lens, which angle of attack can have a value between 0.1° and 5.0°, for example (see Figure 5a ).

[0036] In the embodiment shown, the height of the annular step 10 increases radially outward from the center of the projection lens 5. Figure 5a As can be seen in FIG. 1 , a radial cross-sectional view of the Fresnel structure 9 is shown, wherein: Figure 5a The left end of corresponds to the center of the projection lens 5, and Figure 5a The right end of corresponds to the edge of the projection lens 5. It is entirely possible that the height of the step 10 does not change in the radial direction or changes in another way.

[0037] Furthermore, a refractive structure 14 is provided to soften the light-dark boundary, which is integrated at least in sections into the Fresnel structure 9. Corresponding to the steps 10 of the Fresnel structure 9, the refractive structure 14 has structural elements 15 that are designed as annular or partially annular (see FIG. Figure 3 In this case, the structural elements 15 of the refractive structure 14 can have a width b of between 0.5 mm and 1.0 mm in the radial direction of the projection lens (see Figure 5b ). The height h of the structural element can be, in particular, between 0.1 mm and 1.0 mm, preferably between 0.3 mm and 0.7 mm, for example approximately 0.5 mm.

[0038] In accordance with Figure 2 and Figure 3 In the embodiment of the invention, the refractive structure 14 is integrated into the Fresnel structure 9 only in individual regions. In these regions, at least sections of individual annular steps 10 of the Fresnel structure 9 are replaced by annular or partially annular structural elements 15 of the refractive structure 14 (see Figure 3 ).

[0039] Like the Fresnel structure 9, the structural elements 15 of the refractive structure 14 each have a useful side surface 16 and a disturbing side surface 17 (see Figure 4 b and Figure 5b). In the illustrated embodiment, although the interference side surface 17 of the refractive structure 14 is slightly longer than the interference side surface 12 of the Fresnel structure 9, the attack angle of the interference side surface 17 of the refractive structure 14 is equal to the attack angle of the interference side surface 12 of the Fresnel structure 9.

[0040] The attack angle α' of the useful side surface 16 of the refractive structure 14 is not equal to the attack angle α of the useful side surface 11 of the Fresnel structure 9. In particular, the attack angle α' of the useful side surface 16 of the refractive structure 14 is greater than the attack angle α of the useful side surface 11 of the Fresnel structure 9. Due to the changed attack angle α' of the useful side surface 16 of the refractive structure 14, the refractive caustics of the light passing through the projection lens 5 within the spatial angle range around the bright-dark boundary can be appropriately widened to appropriately soften the bright-dark boundary. This is Figures 8a to 9b It is shown as an example in FIG.

[0041] Figure 8a A low-beam light distribution 18 is shown, which is generated by a projection lens 5 having a Fresnel structure 9 but without a refractive structure 14 integrated therein. The low-beam light distribution 18 has a light-dark boundary 19 . Figure 8b , a variation 20 of the luminous intensity of the low-beam beam distribution 18 in the vertical direction along a line 21 is shown. It is shown that the variation 20 is relatively large, so that there is a very sharp transition between the illuminated spatial angle arranged below the light-dark boundary 19 and the non-illuminated spatial angle arranged above the light-dark boundary 19. Therefore, the gradient of the light intensity of the low-beam beam distribution 18 is very large in the region of the light-dark boundary 19.

[0042] Figure 9a A low-beam light distribution 22 is shown, which is generated by a projection lens 5 having a refractive structure 14 integrated into a Fresnel structure 9 . The low-beam light distribution 22 also has a light-dark boundary 19 . Figure 9b 2 shows a variation 20 of the luminous intensity of the low beam light distribution 22 in the vertical direction along the line 21. It is shown that the variation 20 is relatively small, so that there is a soft transition between the illuminated spatial angle arranged below the light-dark boundary 19 and the non-illuminated spatial angle arranged above the light-dark boundary 19. Therefore, the gradient of the light intensity of the low beam light distribution 22 is relatively small in the region of the light-dark boundary 19.

[0043] It is entirely possible for the refractive structure 14 to be arranged not on the outcoupling side 8 of the projection lens 5 , but on the incoupling side 7 of the projection lens 5 .

[0044] Figure 6 A projection lens 5 is shown which does not have a Fresnel structure but is designed as a lens, in particular as a plano-convex aspherical lens.

[0045] Figure 7 The projection lens 5 is shown, and the projection lens is Figure 6 However, a refractive structure 14 is integrated in the projection lens 5, and the refractive structure is configured to influence the light passing through the projection lens 5 in such a way that the light-dark boundary is softened. Here, the refractive structure 14 can be configured as Figures 2 to 5b The structure 14 of the embodiment of the present invention is similar or identical. In particular, the structure 14 has structural elements 15, at least one of which is designed to be annular or partially annular.

[0046] In accordance with Figure 7 In the embodiment of the invention, the refractive structure 14 is arranged on the coupling side 7, in particular the flat coupling side, of the projection lens 5. It is entirely possible that the refractive structure 14 is arranged on the coupling side 8, in particular the convex coupling side, of the projection lens 5.

[0047] Reference numerals list

[0048] 1 Light Source

[0049] 2 Primary Optics

[0050] 3Optical components of primary optics

[0051] 4 Secondary Optics

[0052] 5. Projection lens for secondary optics

[0053] 6Light from the source

[0054] 7Incoupling side of the projection lens

[0055] 8 Output coupling side of projection lens

[0056] 9Fresnel structure of projection lens

[0057] 10Fresnel structure circular steps

[0058] 11 Useful aspects of Fresnel structures

[0059] 12 Interference side of Fresnel structure

[0060] 13The optical axis of the lens formed by the Fresnel structure

[0061] 14Refraction structure for softening light and dark boundaries

[0062] 15 Structural elements of refractive structures

[0063] 16 Useful aspects of refractive structures

[0064] 17 Interference side of the refractive structure

[0065] 18 Low beam distribution produced by a projection lens having a Fresnel structure in which no refractive structure is integrated

[0066] 19Border between light and dark in low beam distribution

[0067] 20 Changes in the luminous intensity of the low beam distribution

[0068] 21 Line along the vertical direction of the low beam distribution

[0069] 22 Low beam distribution produced by a projection lens with a refractive structure integrated into the Fresnel structure

[0070] b Width of the structural elements of the refractive structure in the radial direction

[0071] h The height of the structural elements of the refractive structure

[0072] Angle of attack of the useful side of the α Fresnel structure

[0073] α' Angle of attack of the useful side of the refractive structure

Claims

1. Headlamps for motor vehicles, including: - at least one light source (1), - an optical system having a plurality of optical components, which is provided for shaping the light (6) originating from the at least one light source (1) and for projecting it into the exterior of the motor vehicle in such a way that a low beam distribution (22) of the headlight with a light-dark boundary (19) is generated, - at least one refractive structure (14), which is arranged on at least one of the optical components and has a plurality of structural elements (15), the at least one structure (14) being arranged to influence a gradient of the light intensity of the low beam distribution (22) in the region of the light-dark boundary (19), The invention is characterized in that the structural elements (15) of the at least one refractive structure have a width (b) between 0.5 mm and 1.0 mm.

2. The headlamp according to claim 1, characterized in that: At least one of the structure elements (15) is designed as annular or partially annular, in particular a plurality of, preferably all of the structure elements (15) of the refractive structure (14) are designed as annular or partially annular.

3. The headlamp according to claim 2, characterized in that: The structural elements (15) configured in an annular or partially annular shape are arranged coaxially or concentrically with each other.

4. The headlamp according to claim 2 or 3, characterized in that: The diameter of a first structural element (15) in the annular or partially annular structural element is smaller than the diameter of a second structural element (15) in the annular or partially annular structural element.

5. The headlamp according to any one of claims 2 to 4, characterized in that At least one of the structure elements (15) is designed to be partially annular, so that it extends over less than 360° in the circumferential direction, in particular only over a sector of a circle.

6. The headlamp according to any one of claims 1 to 5, characterized in that At least one of the optical components is designed as a lens, in particular as an aspherical lens, into which the refractive structure (14) is integrated.

7. The headlamp according to any one of claims 1 to 5, characterized in that At least one of the optical components is designed as a lens having a Fresnel structure (9), into which a refractive structure (14) is integrated.

8. The headlamp according to claim 7, characterized in that: The Fresnel structure (9) comprises an annular step (10), each of which has a useful side surface (11) and an interference side surface (12), the useful side surface (11) being a region of the step (10) which is configured to allow light to pass through the region, and the interference side surface (12) being a region of the step (10) which is not configured to allow light to pass through the region, the useful side surface (11) of the Fresnel structure (9) enclosing an angle of attack (α) with a plane perpendicular to the optical axis (13) of the lens, the angle of attack being, for example, between 0.1° and 5.0°.

9. The headlamp according to claim 8, characterized in that The integration of the refractive structure (14) into the Fresnel structure (9) causes a partial change in the angle of attack (α) of the useful side (11) of the Fresnel structure (9); in particular, the angle of attack of the interfering side (12) of the Fresnel structure (9) is not changed due to the integration of the refractive structure (14) into the Fresnel structure (9).

10. The headlamp according to any one of claims 1 to 9, characterized in that The headlamp comprises a primary optical system (2) and a secondary optical system (4), in particular, the primary optical system (2) is configured to shape light (6) originating from the at least one light source (1) so as to generate an extended light distribution, and the secondary optical system (4) is configured to convert the extended light distribution generated by the primary optical system (2) into a light distribution corresponding to a low-beam light distribution (22) of the headlamp.

11. The headlamp according to claim 10, characterized in that: The secondary optical system (4) has a projection lens (5).

12. The headlamp according to claim 11, characterized in that: The refractive structure (14) is arranged on a projection lens (5) of a secondary optical device (4).

13. The headlamp according to claim 12, characterized in that: The refractive structure (14) is integrated into the coupling-in side (7) or coupling-out side (8) of the projection lens (5) of the secondary optics (4).

14. Method for producing an optical component for a headlamp according to one of claims 1 to 13, wherein: A refractive structure (14) is arranged on the optical component, and the refractive structure is used to influence the gradient of the light intensity of the low beam distribution (22) in the region of the light-dark boundary (19), characterized in that the optical component is made of plastic by injection molding, and the refractive structure (14) is produced during the injection molding.

15. The method according to claim 14, characterized in that For the injection molding, construction data of the optical component to be manufactured are used, the construction data being generated in an iterative method with respect to the shape and arrangement of the structural elements (15) of the refractive structure (14), in particular, in one iterative step, the shape and / or arrangement of at least one of the structural elements (15) is changed in the construction data, and in a subsequent iterative step, it is determined in a simulation whether the optical component manufactured according to these construction data meets legal regulations for low-beam distribution (22), in particular in the area of ​​a light-dark boundary (19).

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