Headlamp for vehicle

Abstract

The invention relates to a headlight for a vehicle, comprising at least one light source for emitting light, said light source comprising an optical unit comprising a projection lens for deflecting said light in order to produce a predetermined light distribution having a bright / dark boundary, said projection lens having a Fresnel structure, the projection lens comprises a plurality of annular effective tooth surfaces which divert the light towards the light distribution, and interference tooth surfaces which do not divert the light towards the light distribution, and the effective tooth surfaces have a preset positioning angle relative to a plane extending perpendicular to the optical axis of the projection lens. The positioning angles of the active tooth flanks arranged at a distance from one another in the radial direction are formed periodically or aperiodically larger and smaller than the base positioning angle, the first active tooth flanks extend at a first positioning angle, which is larger than the base positioning angle by a first difference angle, and the second active tooth flanks extend at a second positioning angle, which is larger than the base positioning angle by a second difference angle. The second positioning angle is smaller than the basic positioning angle by a second difference angle.

Description

Technical Field

[0001] The present invention relates to a headlamp for a vehicle, the headlamp comprising at least one light source for emitting light, the light source comprising an optical unit, the optical unit including a projection lens for deflecting the light, thereby generating a predetermined light distribution having a light / dark dividing line in an area in front of the vehicle, wherein the projection lens has a Fresnel structure comprising a plurality of annular effective tooth surfaces for deflecting the light toward the light distribution and interfering tooth surfaces for not deflecting the light toward the light distribution, the effective tooth surfaces having a predetermined positioning angle relative to a plane extending perpendicular to the optical axis of the projection lens. Background Art

[0002] DE 10 2022 124 019 A1 discloses a headlamp for a vehicle, comprising at least one light source and an optical unit for generating a predetermined light distribution, preferably a low-beam distribution with a light / dark dividing line. The optical unit may include multiple optical components, such as a primary optical system that preshapes the light emitted by the light source and a secondary optical system that reshapes the light from the primary optical system according to the predetermined low-beam distribution. The secondary optical system is formed by a projection lens having a Fresnel structure on the light-exit side. The Fresnel structure has, on the one hand, multiple active flanks that deflect the light to generate the predetermined low-beam distribution. On the other hand, the Fresnel structure has multiple interfering flanks that deflect the light so that it does not contribute to generating the predetermined low-beam distribution. To soften the bright / dark boundary in the low-beam light distribution, the Fresnel structure can have multiple active flanks that extend at a different angle than the other active flanks relative to a plane extending perpendicular to the optical axis of the lens. This can also reduce undesirable color effects in the low-beam light distribution. Summary of the Invention

[0003] The object of the present invention is to further develop a headlamp for a vehicle in such a way that a predetermined light distribution is provided in a manner that is simple in terms of production technology, said light distribution having the smallest possible halo effects on its light / dark dividing line.

[0004] In order to solve this problem, the present invention is characterized in that, in combination with the preamble of claim 1, the positioning angles of the effective tooth surfaces spaced apart from each other in the radial direction are periodically or non-periodically greater than and less than the basic positioning angle, wherein it is provided that a certain number of first effective tooth surfaces distributed in the radial direction extend at a first positioning angle, which is greater than the basic positioning angle by a first differential angle, and a certain number of second effective tooth surfaces extend at a second positioning angle, which is smaller than the basic positioning angle by a second differential angle.

[0005] According to the present invention, color correction in the predetermined light distribution is performed by, on the one hand, each of the plurality of first active tooth flanks of the Fresnel structure has a first angle greater than a base angle, and, on the other hand, each of the plurality of second active tooth flanks has a second angle less than the base angle. This results in a variation of the active tooth flanks that only causes color correction in the predetermined light distribution, in particular at the light / dark boundary of the light distribution. The variation of the angles occurs periodically or aperiodically with respect to a base angle, which is preferably calculated using an algorithm and preferably results in an optimized collimating effect of the active tooth flanks when all active tooth flanks of the Fresnel structure have this base angle. The base angle forms a starting position, similar to a starting position, with the first active tooth flanks slightly tilted in one direction relative to the starting position and the second active tooth flanks slightly tilted in the opposite direction relative to the starting position. A certain influence on the collimation quality of the Fresnel structure is accepted in this manner so that undesirable color halo effects do not become so pronounced that legal requirements are no longer met.

[0006] According to a preferred embodiment of the present invention, adjacent first effective tooth flanks having a first positioning angle and adjacent second effective tooth flanks having a second positioning angle are alternately arranged in a radial direction of the Fresnel structure, that is, starting from the optical axis of the projection lens toward the peripheral edge of the projection lens. For example, adjacent first effective tooth flanks can be spaced at the same distance from one another. For example, adjacent second effective tooth flanks can be spaced at the same distance from one another. For example, adjacent first effective tooth flanks and adjacent second effective tooth flanks can be spaced at the same distance from one another. Advantageously, this provides a uniform light distribution without a halo effect at the light / dark boundary.

[0007] According to a further development of the present invention, the Fresnel structure has interfering flanks extending in the radial direction of the projection lens between the active flanks, the interfering flanks having the same height and / or the same width. Because the interfering flanks are identically designed and preferably also have the same orientation angle relative to a plane extending perpendicular to the optical axis, the annular base of the Fresnel structure formed by adjacent active flanks and interfering flanks extends in an undulating manner along an arc.

[0008] According to a further development of the invention, the first effective tooth flank and the second effective tooth flank have different heights and / or different widths due to their different setting angles, wherein the height is oriented in the axial direction and the width is oriented in the radial direction.

[0009] According to a further development of the invention, the first differential angle of the first effective tooth flank is the same as the second differential angle of the second effective tooth flank. This results in a symmetrical deviation about the center position formed by the basic positioning angle, i.e. the deflection is selected to be equally large on both sides of the center position.

[0010] According to a further development of the invention, a first differential angle of the first effective tooth flank can be greater than a second differential angle of the second effective tooth flank, thereby resulting in an asymmetrical deviation about the center position.

[0011] According to a further development of the invention, the first effective tooth flanks with a first setting angle and the second effective tooth flanks with a second setting angle are arranged distributed over the entire radial direction of the projection lens. In this way, a maximum color correction can be achieved.

[0012] According to a further development of the present invention, only a radial subregion of the projection lens is provided with first and second effective tooth flanks having different alignment angles. The remaining regions of the surface are formed by effective tooth flanks having the same alignment angle, preferably a base alignment angle. Advantageously, the subregion is selected to be only large enough to be required for color correction. By designing the remaining region to optimize the collimation quality, the Fresnel structure can be optimized.

[0013] Further advantages of the invention emerge from the other dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Embodiments of the present invention are explained in more detail below with reference to the accompanying drawings.

[0015] In the picture:

[0016] Figure 1 shows a schematic side view of a projection lens according to the present invention;

[0017] Figure 2 A front view showing a projection lens including a Fresnel structure on a light exit surface;

[0018] Figure 3 Shown along Figure 2 The section line III-III in FIG. 1 passes through a schematic cross section of the projection lens;

[0019] Figure 4A diagram showing the symmetrical deviation of the positioning angles of the first effective tooth flank and the second effective tooth flank over the radial path, and

[0020] Figure 5 The diagram shows an asymmetrical deviation of the setting angles of the first effective tooth flank and the second effective tooth flank relative to the center position, viewed in the radial direction. DETAILED DESCRIPTION

[0021] A headlamp for a vehicle has a plurality of light sources and an optical unit for generating a predetermined light distribution, in particular a low-beam light distribution, with a light / dark boundary.

[0022] The at least one light source is designed as an LED light source. The optical unit preferably includes a primary optical system and a secondary optical system, wherein the primary optical system collimates the light emitted by the light source, and the secondary optical system projects the light from the primary optical system into an area in front of the vehicle to generate a light distribution with a light / dark dividing line.

[0023] exist Figure 1 and 2 , a secondary optical system is shown by way of example. The secondary optical system comprises a plano-convex projection lens 1, which is flat on its light entrance side 2, on which light 3 from the primary optical system or light source is incident. On its convex light exit side 4, facing away from the primary optical system or light source, the projection lens 1 has a Fresnel structure 5, which in this embodiment extends continuously from the optical axis of the projection lens 1 to its peripheral edge 7.

[0024] The Fresnel structure 5 has a plurality of effective tooth flanks N1, N2 and interfering tooth flanks S, each of which is arranged annularly around the optical axis 6 and alternately arranged along a radial direction R. The radial direction R extends in a plane extending perpendicular to the optical axis 6. The radial direction R extends from the optical axis 6 toward the peripheral edge 7 of the projection lens 1 and in the opposite direction.

[0025] The effective tooth surfaces N1, N2 of the Fresnel structure 5 are designed so that they refract or deflect the light 3 used to generate the predetermined light distribution. The interfering tooth surfaces S are designed so that the light refracted or deflected on the interfering tooth surfaces does not contribute to the generation of the predetermined light distribution.

[0026] In this embodiment, a first effective tooth surface N1 is provided, which extends at a first orientation angle β1 relative to a plane E extending perpendicular to the optical axis 6. Furthermore, the Fresnel structure 5 has a plurality of effective tooth surfaces N2, which extend at a second orientation angle β2 relative to the plane E extending perpendicular to the optical axis 6.

[0027] The first effective tooth surface N1 and the second effective tooth surface N2 are characterized in that the first effective tooth surface and the second effective tooth surface are arranged on the calculated basic effective tooth surface N B On both sides of the basic effective tooth surface, the basic effective tooth surface extends at a basic positioning angle α with respect to the plane E. The first effective tooth surface N1 is opposite to the basic effective tooth surface N on the first side. B With the first difference angle Δφ 1 The second effective tooth surface N2 is arranged at an angle, and the second effective tooth surface N2 is arranged at an angle. B On the opposite sides of the 2 Set at an angle.

[0028] Basic effective tooth surface N B With a basic positioning angle α and calculated by, for example, an algorithm, the Fresnel structure 5 is thereby optimized. In particular, the basic effective tooth surface N B This design results in the projection lens 1 having a particularly high-quality collimation.

[0029] Basic effective tooth surface N B The trend is Figure 3 The first effective tooth surface N1 and the second effective tooth surface N2 are shown by dotted lines. B The basic positioning angle α has a difference angle Δφ 1 and Δφ 2 To minimize the deviation, the undesirable halo effect on the light / dark boundary of the light distribution is avoided. For this purpose, in this embodiment, only the first effective tooth surface N1 and the second effective tooth surface N2 are provided. The positioning angle β1 of the first effective tooth surface N1 is therefore equal to: β1 = α + Δφ 1 The positioning angle β2 of the second effective tooth surface N2 is therefore equal to: β2 = α + Δφ 2 .

[0030] In the present embodiment, the first effective tooth flanks N1 and the second effective tooth flanks N2 are alternately arranged along the radial direction R, wherein the interfering tooth flanks S extend between the first effective tooth flanks N1 and the second effective tooth flanks N2 .

[0031] According to an alternative embodiment of the present invention (not shown), the first effective tooth surfaces N1 and the second effective tooth surfaces N2 may not be arranged alternately in the radial direction R, so that, for example, two first effective tooth surfaces N1 and then two second effective tooth surfaces N2 are arranged in the radial direction R. Adjacent first effective tooth surfaces N1 and second effective tooth surfaces N2 may be arranged periodically in the radial direction R (as in the present embodiment).

[0032] According to an alternative embodiment (not shown), the first and second effective tooth flanks may also be arranged aperiodically, wherein, for example, the number of first effective tooth flanks N1 and the number of second effective tooth flanks N2 are also different.

[0033] In order to produce a high collimation quality and to avoid color halos at the light / dark boundary, a periodic arrangement of the first effective tooth flanks N1 and the second effective tooth flanks N2 of the Fresnel structure 5 is preferably provided.

[0034] According to the present invention Figure 4 In the first embodiment, the first difference angle Δφ of the first effective tooth surface N1 1 The second difference angle Δφ with the second effective tooth surface N2 2 Therefore, along the radial direction R of the Fresnel structure 5, the first effective tooth surface N1 and the second effective tooth surface N2 are made relative to the basic effective tooth surface N B symmetrical deviation of the basic positioning angle α, wherein the basic positioning angle α forms the first difference angle Δφ 1 and the second difference angle Δφ 2 Thus, a relatively uniform mixing of the light 3 with different wavelength components occurs.

[0035] According to the present invention Figure 5 An alternative embodiment can also be performed by forming the effective tooth surface N1 and the second effective tooth surface N2 'with a difference angle Δφ 1 and Δφ 2 asymmetric deviation.

[0036] The same reference numerals denote the same components or the same component functions.

[0037] As Figure 5 It can be seen that the second difference angle Δφ of the second effective tooth surface N2 ′ 2 The first difference angle Δφ is smaller than the first effective tooth surface N1. 1 Therefore, the second effective tooth surface N2' is compared with the Figure 4 The implementation form is better than that according to Figure 3 and 4 The second effective tooth flank N2 of the embodiment is steeper.

[0038] As Figure 3 It can be seen that the interfering tooth surface S always extends between the first effective tooth surface N1 and the second effective tooth surface N2. The interfering tooth surfaces S of the Fresnel structure each have the same height h S and the same width b S The height h of the interfering tooth surface S S The width b is formed by the distance of the salient points 8 of the Fresnel structure 5 relative to a plane E extending through a base line 9 of the Fresnel structure 5 and containing the corresponding interfering tooth flank S. S It is the net distance of the interfering tooth surface S projected onto plane E.

[0039] Due to the different positioning angles β1, β2 of the effective tooth surfaces N1, N2, the effective tooth surfaces have different heights h N1 、h N2 and / or different widths b N1 、b N2 .

[0040] As Figure 3 It can be seen that the base lines 9 of the Fresnel structure 5 do not extend in a common plane, but rather extend in an undulating manner along an arc. Base lines 9 arranged adjacent to each other in the radial direction R therefore extend at different heights. The base lines 9 preferably extend periodically in the radial direction R with a height offset.

[0041] In the present embodiment, it is assumed that the first effective tooth flank N1 and the second effective tooth flank N2 extend continuously in the radial direction R from the optical axis 6 to the circumferential edge 7 at their different positioning angles β1 , β2 .

[0042] According to an alternative embodiment of the present invention (not shown), the first effective tooth flanks N1 and the second effective tooth flanks N2, formed with different orientation angles β1 and β2, can also extend only over a radial subregion of the Fresnel structure 5. The remaining region of the Fresnel structure 5 then preferably comprises only effective tooth flanks having the same orientation angle, preferably a base orientation angle α. This allows for optimal collimation quality in the remaining region of the Fresnel structure 5, while achieving color correction in the light distribution in this subregion due to deviations from the base orientation angle α.

[0043] According to an alternative embodiment of the invention (not shown), the Fresnel structure 5 can be provided on the light entrance side 2 of the projection lens 1 instead of on the light exit side 4 .

[0044] Basic effective tooth surface N B The basic positioning angle α can be in the range of 0.1° to 5.0°. 1 and Δφ 2 It may be in the range between 0.05° and 0.5°.

[0045] Preferably, the projection lens 1 is made of polycarbonate material and manufactured by injection molding.

[0046] It should be noted that the light / dark dividing line is produced by the imaging of the edge of the light source. Alternatively, an additional light barrier can also be provided for this purpose, which is arranged behind the projection lens in the main emission direction.

[0047] Reference Signs List

[0048] 1 Projection lens

[0049] 2 Light incident side

[0050] 3 Light

[0051] 4 Light emitting side

[0052] 5 Fresnel structure

[0053] 6 optical axes

[0054] 7 Circumferential edge

[0055] 8 bumps

[0056] 9 Baseline

[0057] 10 waves R radial direction E plane S interference tooth surface N1, N2, N2' effective tooth surface N B Basic effective tooth surface α basic positioning angle Difference angle h S 、h N1 、h N2 Height b S 、b N1 、b N2 Width β1, β2 positioning angle

Claims

1. A headlamp for a vehicle, comprising at least one light source for emitting light (3), the light source comprising an optical unit containing a projection lens (1) for deflecting the light (3) so as to generate a predetermined light distribution with a light / dark dividing line in the area in front of the vehicle, wherein: The projection lens (1) has a Fresnel structure (5), which includes a plurality of annular effective tooth surfaces (N1, N2) for redirecting the light (3) toward the light distribution and an interference tooth surface (S) for not redirecting the light (3) toward the light distribution, wherein the effective tooth surfaces (N1, N2) have a predetermined positioning angle (β1, β2) relative to a plane (E) extending perpendicular to the optical axis (6) of the projection lens (1), characterized in that the positioning angles (β1, β2) of the effective tooth surfaces (N1, N2) spaced apart from each other in a radial direction (R) are periodically or non-periodically greater than and less than a basic positioning angle (α), wherein it is provided that a certain number of first effective tooth surfaces (N1) distributed in the radial direction (R) extend at a first positioning angle (β1), the first positioning angle being greater than the basic positioning angle (α) by a first difference angle (Δφ) 1 ), and a certain number of second effective tooth surfaces (N2) extend at a second positioning angle (β2), the second positioning angle being smaller than the basic positioning angle (α) by a second difference angle (Δφ) 2 ).

2. The headlamp according to claim 1, characterized in that Basic effective tooth surface (N B ) can be determined by calculation, wherein the basic positioning angle describes the optically optimized design of the projection lens (1).

3. The headlamp according to claim 1 or 2, characterized in that Along the radial direction (R) of the Fresnel structure (5), first effective tooth surfaces (N1) and second effective tooth surfaces (N2) are alternately arranged.

4. The headlamp according to any one of claims 1 to 3, characterized in that Select the first difference angle (Δφ 1 ) and the second difference angle (Δφ 2 ), so that the color halo on the light / dark dividing line of the light distribution is smaller than the color halo on the light / dark dividing line of the following light distribution, the light distribution is formed as a basic effective tooth surface (N1, N2) with a basic positioning angle (α) B ) is generated.

5. The headlamp according to any one of claims 1 to 4, characterized in that An interfering tooth flank (S) is always provided between the first effective tooth flank (N1) and / or the second effective tooth flank (N2).

6. The headlamp according to any one of claims 1 to 5, characterized in that The interfering tooth surfaces (S) of the Fresnel structure (5) respectively have the same height (h S ) and / or the same width (b S ).

7. The headlamp according to any one of claims 1 to 6, characterized in that The first effective tooth surface (N1) of the Fresnel structure (5) and the second effective tooth surface (N2) of the Fresnel structure (5) have different heights (h N1 、h N2 ) and / or different widths (b N1 、b N2 ).

8. The headlamp according to any one of claims 1 to 7, characterized in that The first difference angle (Δφ 1 ) and the second difference angle (Δφ 2 ) are the same size.

9. The headlamp according to any one of claims 1 to 7, characterized in that The first difference angle (Δφ 1 ) is greater than the second difference angle (Δφ 2 ).

10. The headlamp according to any one of claims 1 to 9, characterized in that Effective tooth surfaces (N1, N2) with different positioning angles (β1, β2) extend continuously along a radial direction (R) from an optical axis (6) of the projection lens (1) to a circumferential edge (7) of the projection lens (1).

11. The headlamp according to any one of claims 1 to 9, characterized in that The first effective tooth surface (N1) and the second effective tooth surface (N2) extend in at least one radial partial region between the optical axis and the circumferential edge (7) of the projection lens (1), and in the remaining region, the Fresnel structure (5) has a basic effective tooth surface (N B ).

12. The headlamp according to any one of claims 1 to 11, characterized in that The Fresnel structure (5) is arranged on the light exit side (4) of the projection lens (1).

13. The headlamp according to any one of claims 1 to 12, characterized in that The projection lens (1) is of plano-convex design.

14. The headlamp according to any one of claims 1 to 13, characterized in that The basic positioning angle (α) is in the range between 0.1° and 5.0°.

15. The headlamp according to any one of claims 1 to 14, characterized in that The projection lens (1) is made of polycarbonate material.

Images