Lighting Device for a Motor Vehicle Headlamp

Abstract

Illumination device (10) for a motor vehicle headlight, which comprises the following: a first light module (100) for producing light distribution, a bulb shield (300) having a bulb shield (300), which comprises an optically relevant shield edge (310) for producing a cut-off line, a projection lens (400) with an optical axis (A), which is designed to image the light that can be produced by the first light module (100) in front of the illumination device (10), wherein the projection lens (400) is designed as a Fresnel lens, which Fresnel lens has a base body (410) and several annular steps (420) arranged on the base body (410), wherein each step (420) has a main surface (420a) to project the light beams of the at least one light module (100) in front of the illumination device (10) and a sloping surface (420b) extending from the base body (410) to the main surface (420a), wherein the main surface of each step is curved and has a focal point, which focal point is arranged horizontally and/or vertically displaced from the optical axis of the Fresnel lens, and wherein adjacent steps have different focal points from one another.

Claims

1. An illumination device (10) for a motor vehicle headlight the illumination device (10) comprising: at least one first light module (100) having at least one light source to produce light distribution in the direction of a main emission direction, wherein the first light module (100) is designed to emit light beams in a main emission direction; a projection lens (300) with an optical axis (A), which projection lens (300) is designed to image the light that can be produced by the first light module (100) in front of the illumination device (10), wherein the projection lens (300) is designed as a Fresnel lens, which Fresnel lens has a base body (310) and several annular steps (320) arranged on the base body (310), which steps (320) are arranged substantially concentrically to one another, wherein each step (320) has a main surface (320a) to project the light beams of the at least one light module (100) in front of the illumination device (10) and a sloping surface (320b) extending from the base body (310) to the main surface (320a); a bulb shield (400), wherein the bulb shield (400) comprises an optically relevant shield edge (410) for producing a cut-off line, wherein the shield edge (410) intersects the optical axis (A) of the Fresnel lens, and wherein the first light module (100) is arranged on an upper side of the bulb shield and cooperates in combination with the optically relevant shield edge (410) of the bulb shield (400) to produce light distribution, wherein the main surface (320a) of each step (320) is curved and has at least one focal point (F1, F2, F3, F4), which focal point (F1, F2, F3, F4) is arranged horizontally and/or vertically displaced from the optical axis (A) of the Fresnel lens, and wherein adjacent steps (320) have different focal points (F1, F2, F3, F4) from one another.

2. The illumination device according to claim 1, wherein the bulb shield has a longitudinal axis, wherein the longitudinal axis of the bulb shield (400) is arranged in a horizontal plane in an installed state of the illumination device (100) in a motor vehicle headlight, and wherein the optically relevant shield edge is designed to produce an asymmetrical cut-off line, and wherein the first light module (100) cooperates in combination with the optically relevant shield edge (410) of the bulb shield (400) to produce dipped beam distribution.

3. The illumination device according to claim 1, wherein the illumination device (10) comprises at least one second light module (200) having at least one light source to produce full beam distribution.

4. The illumination device according to claim 3, wherein the second light module (200) is arranged on a lower side of the bulb shield (400).

5. The illumination device according to claim 1, wherein the main surface (320a) of the steps (320a) is convex or concave.

6. The illumination device according to claim 1, wherein the main surface (320a) and the sloping surface (320b) of a step (320) form a step edge (320c) in a common surface section line, wherein the step edges (320c) are spaced from adjacent step edges (320c) by a distance less than 20 μm.

7. A motor vehicle headlight having at least one illumination device (10) in accordance with claim 1.

8. The illumination device according to claim 6, wherein the step edges (320c) are spaced from adjacent step edges (320c) by a distance less than 10 μm.

9. The illumination device according to claim 6, wherein the step edges (320c) are spaced from adjacent step edges (320c) by a distance less than 5 μm.

Description

[0023] The invention is explained below in more detail based on exemplary drawings. In the drawings,

[0024] FIG. 1 shows a side view of an exemplary illumination device having a projection lens designed as a Fresnel lens, wherein the Fresnel lens comprises several steps that are substantially concentric with each other, and

[0025] FIG. 2 shows a cross-sectional view of a step of the Fresnel lens from FIG. 1.

[0026] FIG. 1 shows an exemplary illumination device 10 for a motor vehicle headlight, which illumination device comprises a first light module 100 having at least one light source to produce dipped beam distribution in the direction of a main emission direction, wherein the first light module 100 is designed to emit light beams in a main emission direction.

[0027] Furthermore, the illumination device 10 comprises a projection lens 300 with an optical axis A, which projection lens 300 is designed to image the light that can be produced by the first light module 100 in front of the illumination device 10, wherein the projection lens 300 is designed as a Fresnel lens.

[0028] The Fresnel lens comprises a base body 310 and several annular steps 320 arranged on the base body 310, which steps 320 are arranged substantially concentrically to one another, wherein each step 320 has a main surface 320a to project the light beams of the at least one light module 100 in front of the illumination device 10 and a sloping surface 320b extending from the base body 310 to the main surface 320a, as shown more clearly in FIG. 2.

[0029] Moreover, the main surface 320a and the sloping surface 320b of a step 320 form a step edge 320c in a common surface section line, wherein the step edges 320c are spaced from adjacent step edges 320c by a distance smaller than 20 μm, preferably smaller than 10 μm, preferably smaller than 5 μm.

[0030] Furthermore, the illumination device 10 comprises a bulb shield 400 with a longitudinal axis, wherein the longitudinal axis of the bulb shield 400 is arranged in a horizontal plane in an installed state of the illumination device 100 in a motor vehicle headlight, wherein the bulb shield 400 comprises an optically relevant shield edge 410 for producing an asymmetrical cut-off line, wherein the shield edge 410 intersects the optical axis A of the Fresnel lens.

[0031] The first light module 100 is arranged on an upper side of the bulb shield and cooperates in combination with the optically relevant shield edge 410 of the bulb shield 400 to produce dipped beam distribution.

[0032] In general, the terms used in the following relating to a location or an orientation, such as “horizontal”, “vertical”, “in a horizontal direction”, “in a vertical direction”, “top”, “bottom”, in front of“, “behind”, “below”, “above” etc. refer to a correct installation position of the illumination device in question in a motor vehicle headlight.

[0033] The main surface 320a of each step 320 is curved and respectively has a focal point F1, F2, F3, F4, which focal point F1, F2, F3, F4 is arranged horizontally and/or vertically displaced from the optical axis A of the Fresnel lens, and wherein adjacent steps 320 have different focal points F1, F2, F3, F4 from one another.

[0034] As shown in FIG. 1, a focal point F1 is assigned to the outermost step of the Fresnel lens, a focal point F2 to the next inner step and so on.

[0035] The curved main surfaces 320a of the steps can be convex or concave; in FIG. 2, the exemplary step is formed with a convex main surface 320a.

[0036] Furthermore, the exemplary illumination device from FIG. 1 comprises a second light module 200 having at least one light source to produce full beam distribution, wherein the second light module 200 is arranged on a lower side of the bulb shield 400.

REFERENCE LIST

[0037] Illumination device . . . 10 [0038] First light module . . . 100 [0039] Second light module . . . 200 [0040] Projection lens . . . 300 [0041] Base body . . . 310 [0042] Step . . . 320 [0043] Main surface . . . 320a [0044] Sloping surface . . . 320b [0045] Step edge . . . 320c [0046] Bulb shield . . . 400 [0047] Shield edge . . . 410 [0048] Focal point . . . F1, F2, F3, F4