Lighting device for motor vehicle headlights

Abstract

A lighting device for a motor vehicle headlamp, the lighting device comprising the following components: a first light module for generating a light distribution; a beam stop having a beam stop, the beam stop comprising an optically relevant stop edge for generating a light-dark boundary; a projection lens having an optical axis, the shadow lens being configured to project light that can be generated by the first light module in front of the lighting device, the projection lens being configured as a Fresnel lens, the Fresnel lens comprising a base body and a plurality of annular steps arranged on the base body, each step having a main surface for projecting a light beam of the at least one light module in front of the lighting device and a rising surface extending from the base body to the main surface, wherein the rising surface encloses a rising angle relative to the optical axis, and wherein the main surface and the rising surface form a step edge at a common surface intersection line, wherein the rising angle changes continuously along the circumference of the step edge.

Description

Technical Field

[0001] The invention relates to a lighting device for a motor vehicle headlight and a motor vehicle headlight having at least one lighting device. Background Art

[0002] The lighting device includes the following components:

[0003] at least one first light module for generating a light distribution using at least one first light source and a second light source, wherein the first light source is configured to emit light along a first radiation direction, and wherein the second light source is configured to emit light along a second radiation direction, wherein the first and second radiation directions enclose an angle greater than zero degrees relative to one another,

[0004] a beam shutter, wherein the beam shutter comprises an optically relevant shutter edge for generating a light-dark boundary, wherein the first light module is arranged on the upper side of the beam shutter and cooperates in combination with the optically relevant shutter edge of the beam shutter for generating a light distribution,

[0005] - a projection lens having an optical axis, which is configured to project light that can be generated by the first light module in front of the lighting device, wherein the projection lens is configured as a Fresnel lens, which comprises a base body and a plurality of annular steps arranged on the base body, the steps being arranged substantially concentrically with one another, wherein each step has a main surface for projecting a light beam of the at least one light module in front of the lighting device and a rising surface extending from the base body to the main surface, wherein the rising surface encloses a rising angle with respect to the optical axis, and wherein the main surface and the rising surface form a step edge at a common surface intersection line.

[0006] A Fresnel lens (more precisely: a Fresnel step lens) is an optical lens that can realize the structure of a large lens with a short focal length without the weight and volume of a conventional lens.

[0007] The volume of a Fresnel lens is reduced by dividing it into annular zones. The thickness is reduced in each of these zones, resulting in a series of annular steps. Because light is refracted only at the main surface of the lens, the refraction angle depends not on the thickness but solely on the angle between the two lens surfaces. As a result, the lens maintains its optical performance. Although the image quality is negatively impacted by the step structure, this is not a significant issue in many applications. An example of this is the illumination beam path in all types of headlights.

[0008] However, the rising surface of each step can lead to undesirable light straying, which can be problematic for many applications, particularly in the field of motor vehicle headlights, where legal framework conditions must be met precisely. Summary of the Invention

[0009] The object of the present invention is to provide an improved lighting device.

[0010] This object is achieved in that the rise angle varies continuously along the annular circumference of the step edge.

[0011] It can be provided that the first and second light sources are arranged in a horizontal plane when the lighting device is installed in a motor vehicle headlamp.

[0012] It can be provided that the light beam shutter has a longitudinal axis, wherein the longitudinal axis of the light beam shutter is arranged in a horizontal plane when the lighting device is installed in a motor vehicle headlamp, wherein the light beam shutter comprises an optically relevant shutter edge for generating an asymmetrical light-dark boundary, wherein the first light module is arranged on an upper side of the light beam shutter and cooperates in combination with the optically relevant shutter edge of the light beam shutter for generating a low-beam beam distribution.

[0013] It can be provided that the rise angle varies continuously along the annular circumference of the step edge so that the variation of the rise angle follows a sinusoidal variation curve, wherein the rise angle of each step has a corresponding step maximum value along a vertical axis intersecting the optical axis of the Fresnel lens, and wherein the rise angle of each step has a corresponding step minimum value along a horizontal axis intersecting the optical axis of the Fresnel lens.

[0014] Surprisingly, it has been found that a larger rise angle in the vertical direction than in the horizontal direction significantly reduces the astigmatism in the projected light distribution.

[0015] Usually, the following terms related to position or direction, such as "horizontal", "vertical", "in the horizontal direction", "in the vertical direction", "above", "below", "in front", "behind", "beneath", "above", etc., also relate to the prescribed installation position of a specific lighting device in a motor vehicle headlamp.

[0016] It can be provided that the maximum value of the rise angle of the step increases in the vertical direction starting from the optical axis.

[0017] It can be provided that the minimum value of the rise angle of the step increases in the horizontal direction starting from the optical axis.

[0018] It may be provided that the lighting device comprises at least one second light module having at least one light source for generating a high-beam light distribution.

[0019] It can be provided that the second light module is arranged on the underside of the light beam shutter and cooperates to generate a high-beam beam distribution.

[0020] It can be provided that the minimum value of the rise angle along the horizontal axis is 1 to 3 degrees.

[0021] It can be provided that the maximum value of the rise angle along the vertical axis is 3 to 12 degrees, preferably 3 to 6 degrees, in particular 6 degrees.

[0022] This object is also achieved by a motor vehicle headlight having at least one lighting device according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be explained in detail below with the aid of exemplary drawings.

[0024] Figure 1 An exemplary lighting device is shown in a vertical cross section, comprising a first and a second light module and a projection lens designed as a Fresnel lens, wherein the Fresnel lens has a base body with a plurality of annularly arranged steps;

[0025] Figure 2 Shown in horizontal cross section Figure 1 An exemplary lighting device;

[0026] Figure 3 A detailed view of the steps is shown in cross section; and

[0027] Figure 4 The end side of the Fresnel lens is shown. DETAILED DESCRIPTION

[0028] Figure 1 An exemplary lighting device 10 for a motor vehicle headlamp is shown, comprising a first light module 100 for generating a low-beam beam distribution using at least one first and one second light source 110, 120, wherein the first and second light sources 110, 120 are arranged in a horizontal plane when the lighting device 10 is installed in the motor vehicle headlamp, as in FIG. Figure 2 As can be seen in .

[0029] The first light source 110 is configured to emit light along a first radiation direction X1, wherein the second light source 120 is configured to emit light along a second radiation direction X2, wherein the first and second radiation directions X1, X2 enclose an angle W1 greater than zero degrees relative to each other, as also in Figure 2 As clearly visible in.

[0030] Furthermore, the lighting device 10 includes a second light module 200 , which has at least one light source for generating a high-beam light distribution.

[0031] Furthermore, the lighting device comprises a beam shutter 300 having a longitudinal axis, wherein the longitudinal axis of the beam shutter 300 is arranged in a horizontal plane when the lighting device 10 is installed in the motor vehicle headlamp, wherein the beam shutter 300 comprises an optically relevant shutter edge 310 for generating an asymmetrical light-dark boundary, wherein the first light module 100 is arranged on the upper side of the beam shutter 300 and cooperates in combination with the optically relevant shutter edge 310 of the beam shutter for generating a low-beam beam distribution.

[0032] The second light module 200 is arranged on the underside of the beam interrupter 300 and is configured to cooperate to generate a high-beam beam distribution.

[0033] Furthermore, the lighting device 10 comprises a projection lens 400 having an optical axis A, which is configured to project light that can be generated by the first light module 100 in front of the lighting device 10, wherein the projection lens 400 is configured as a Fresnel lens, which comprises a base body 410 and a plurality of annular steps 420 arranged on the base body 410, the steps 420 being arranged substantially concentrically with one another, as further described in Figure 4 As can be seen in .

[0034] Each step 420 has a main surface 420a for projecting a light beam of the at least one light module 100 to the front of the lighting device 10 and a rising surface 420b extending from the base body 410 to the main surface 420a, wherein the rising surface 420b encloses a rising angle W2 with respect to the optical axis A, and wherein the main surface 420a and the rising surface 420b form a step edge 430 at a common surface intersection line, as shown in FIG. Figure 3 As can be seen in detail in Figure 3 The optical axis A shown in FIG is an axis parallel to the optical axis of the Fresnel lens and is intended to illustrate the formation of the rise angle W2 .

[0035] The rise angle W2 varies continuously along the annular circumference of the step edge 420 so that the variation of the rise angle W2 follows a sinusoidal variation curve, wherein the rise angle W2 of each step has a corresponding step maximum along the vertical axis V1 intersecting the optical axis A of the Fresnel lens, and wherein the rise angle W2 of each step has a corresponding step minimum along the horizontal axis H1 intersecting the optical axis A of the Fresnel lens, as shown in FIG. Figure 4 As can be seen more clearly in

[0036] If, for example, one proceeds clockwise from the horizontal axis H1 along the annular course or circumference of the step edge 430 of the step 420 (to illustrate the end face of the Fresnel lens), Figure 4 As a starting point, the rise angle W2 directly reaches its minimum at the horizontal axis H1, where it then increases continuously or continuously until the rise angle of the corresponding step reaches its maximum at the vertical axis V1. If the perimeter of the step is followed further, the rise angle W2 decreases again until it reaches another minimum at the horizontal axis H1. The rise angle W2 then decreases again until it reaches another maximum at the vertical axis V1.

[0037] Furthermore, the maximum value of the rise angle W2 of the steps increases in the vertical direction starting from the optical axis A. In other words, starting from one step, the next step with a larger annular perimeter of the step edge also has a larger maximum rise angle W2. This continues in the vertical direction or along the vertical axis V1. The maximum value of the rise angle W2 along the vertical axis can vary from 3 degrees to 10 degrees, preferably from 3 degrees to 6 degrees.

[0038] Furthermore, the minimum value of the step rise angle W2 increases in the horizontal direction starting from the optical axis A, wherein the description in the previous paragraph applies vice versa to the progression of the minimum value in the horizontal direction. The minimum value of the rise angle W2 along the horizontal axis H1 can vary from 1 degree to 3 degrees.

Claims

1. A lighting device (10) for a motor vehicle headlamp, the lighting device (10) comprising the following components: - at least one first light module (100) for generating a light distribution using at least one first and one second light source (110, 120), wherein the first light source (110) is configured to emit light along a first radiation direction (X1), and wherein the second light source (120) is configured to emit light along a second radiation direction (X2), wherein the first and second radiation directions (X1, X2) enclose an angle (W1) greater than zero degrees relative to each other, a beam shutter (300), wherein the beam shutter (300) comprises an optically relevant shutter edge (310) for generating a light-dark boundary, wherein the first light module (100) is arranged on the upper side of the beam shutter (300) and cooperates in combination with the optically relevant shutter edge (310) of the beam shutter for generating a light distribution, a projection lens (400) having an optical axis (A), the projection lens being configured to project light that can be generated by the first light module (100) in front of the lighting device (10), wherein the projection lens (400) is configured as a Fresnel lens, the Fresnel lens comprising a base body (410) and a plurality of annular steps (420) arranged on the base body (410), the steps (420) being arranged substantially concentrically with one another, wherein each step (4 20) having a main surface (420a) for projecting a light beam of the at least one light module (100) to the front of the lighting device (10) and a rising surface (420b) extending from the base body (410) to the main surface (420a), wherein the rising surface (420b) encloses a rising angle (W2) relative to the optical axis (A), and wherein the main surface (420a) and the rising surface (420b) form a step edge (430) in a common surface intersection line, It is characterized in that The rise angle (W2) varies continuously along the annular periphery of the step edge (430).

2. The lighting device according to claim 1, characterized in that The first and second light sources (110, 120) are arranged in a horizontal plane when the lighting device (10) is installed in a motor vehicle headlamp.

3. The lighting device according to claim 1 or 2, characterized in that: The light beam interrupter has a longitudinal axis, wherein the longitudinal axis of the light beam interrupter (300) is arranged in a horizontal plane when the lighting device (10) is installed in a motor vehicle headlamp, wherein the light beam interrupter (300) comprises an optically relevant interrupter edge (310) for generating an asymmetrical light-dark boundary, wherein the first light module (100) is arranged on the upper side of the light beam interrupter (300) and cooperates in combination with the optically relevant interrupter edge (310) of the light beam interrupter for generating a low-beam distribution.

4. The lighting device according to claim 1 or 2, characterized in that: The rise angle (W2) changes continuously along the annular periphery of the step edge (430) in such a way that the change of the rise angle (W2) follows a sinusoidal change curve, wherein the rise angle (W2) of each step has a corresponding step maximum value along a vertical axis (V1) intersecting the optical axis (A) of the Fresnel lens, and wherein the rise angle (W2) of each step has a corresponding step minimum value along a horizontal axis (H1) intersecting the optical axis (A2) of the Fresnel lens.

5. The lighting device according to claim 1 or 2, characterized in that: The maximum value of the rising angle (W2) of the step increases along the vertical direction starting from the optical axis (A).

6. The lighting device according to claim 1 or 2, characterized in that: The minimum value of the rising angle (W2) of the step increases along the horizontal direction starting from the optical axis (A).

7. The lighting device according to claim 1 or 2, characterized in that: The lighting device (10) comprises at least one second light module (200), which has at least one light source for generating a high-beam light distribution.

8. The lighting device according to claim 7, characterized in that The second light module (200) is arranged at the lower side of the beam interrupter (300) and cooperates to generate a high-beam distribution.

9. The lighting device according to claim 1 or 2, characterized in that: The minimum value of the rise angle (W2) along the horizontal axis (H1) is 1 to 12 degrees.

10. The lighting device according to claim 1 or 2, characterized in that: The maximum value of the rise angle (W2) along the vertical axis is 3 to 12 degrees.

11. The lighting device according to claim 10, characterized in that The maximum value of the rise angle (W2) along the vertical axis is 6 degrees.

12. Motor vehicle headlamp comprising at least one lighting device (10) according to any one of claims 1 to 11.

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