Optical surface and lighting device for vehicles

Abstract

An optical surface for softening a light/dark border of a lighting device for vehicles, having a grid of lens elements distributed over a base surface, by means of which a light bundle passing through the optical surface can be diffused in relation to a main direction, wherein the lens elements are each designed as micro-lens elements, which, on one hand, exhibit a central main emission surface, which follows a contour of the base surface, by means of which the light beams of the light bundle are deflected in a main direction corresponding to the contour of the base surface, and on the other hand, exhibit subsidiary emission surfaces, running at an angle to the central main emission surface, by means of which light beams of the light bundle are diffused in a diffusion direction in relation to the main direction.

Claims

1. An optical surface for softening a light/dark border of a lighting device for vehicles comprising: a grid of lens elements distributed over a base surface, by means of which a light bundle passing through the optical surface can be diffused in relation to a main direction, wherein the lens elements are each designed as micro-lens elements, which have a central main emission surface following a contour of the base surface, by means of which light beams of the light bundle are deflected in a manner corresponding to the contour of the base surface in the main direction, and which has a subsidiary emission surface outwardly projecting from the base surface running at an angle to the central main emission surface, by means of which light beams of the light bundle are diffused in relation to the main direction in a diffusion direction, wherein the micro-lens elements are each designed in the shape of a dish at the central main emission surface, and wherein the central main emission surface of each micro-lens element is flat.

2. The optical surface according to claim 1, wherein the central main emission surface has substantially the same contour as the contour of the base surface of the optical surface running in a normal direction, displaced parallel thereto.

3. The optical surface according to claim 1 wherein the central main emission surface exhibits a spacing to the base surface of the optical surface in a range of 0.001 mm to 0.15 mm.

4. The optical surface according to claim 1 wherein the subsidiary emission surface runs at an angle, in a range of 74° to 89.9°, from the central main emission surface toward the base surface with respect to the central main emission surface.

5. The optical surface according to claim 1 wherein the micro-lens elements are disposed at a spacing to one another, wherein the base surface of the optical surface extends between the micro-lens elements.

6. The optical surface according to claim 1 wherein the base surface of the optical surface is designed such that it is at least one of flat and/or convex, or corresponds to freeform surface.

7. The optical surface according to claim 1 wherein the micro-lens elements form a boundary surface with the base surface of the optical surface.

8. An optical surface for softening a light/dark border of a lighting device for vehicles comprising: a grid of lens elements distributed over a base surface, by means of which a light bundle passing through the optical surface can be diffused in relation to a main direction, wherein the lens elements are each designed as micro-lens elements, which have a central main emission surface following a contour of the base surface, by means of which light beams of the light bundle are deflected in a manner corresponding to the contour of the base surface in the main direction, and which has a subsidiary emission surface including opposing straight first portions extending perpendicularly upwardly from the base surface and a second curved portion adjoining the central main emission surface in a continuous manner, by means of which light beams of the light bundle are diffused in relation to the main direction in a diffusion direction, wherein the micro-lens elements are each designed in the shape of a dish at the central main emission surface, and wherein the central main emission surface of each micro-lens element is domed.

9. An optical surface for softening a light/dark border of a lighting device for vehicles comprising: a grid of lens elements distributed over a base surface, by means of which a light bundle passing through the optical surface can be diffused in relation to a main direction, wherein the lens elements are each designed as micro-lens elements, which have a central main emission surface following a contour of the base surface, by means of which light beams of the light bundle are deflected in a manner corresponding to the contour of the base surface in the main direction, and which has a subsidiary emission surface outwardly projecting from the base surface running at an angle to the central main emission surface, by means of which light beams of the light bundle are diffused in relation to the main direction in a diffusion direction, wherein the micro-lens elements are each designed in the shape of a dish at the central main emission surface, wherein the central main emission surface of each micro-lens element is flat or domed, wherein the central main emission surface exhibits a spacing to the base surface of the optical surface in a range of 0.001 mm to 0.15 mm, and wherein the subsidiary emission surface runs at an angle, in a range of 74° to 89.9°, from the central main emission surface toward the base surface with respect to the central main emission surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Reference is now made more particularly to the drawings, which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views.

(2) FIG. 1 is a schematic partial view of an optical surface having a micro-lens element.

(3) FIG. 2 is a perspective partial view of an optical surface having micro-lens elements distributed thereon.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) The invention relates to optical surfaces that can be used, for example, as lens surfaces in lighting devices for vehicles. The light device for vehicles can, for example, be designed as a headlamp having a projection module. This projection module has a light source, a reflector, a lens, and an aperture disposed between the reflector and the lens. The aperture has an aperture edge, which serves to project a light/dark border in an asymmetrical low beam light distribution, for example. The lens is disposed in the main beam direction in front of the reflector and the aperture. The lens can exhibit a flat light entry surface and a convex light exit surface.

(5) An optical surface 1 is schematically depicted in FIG. 1, which can form, for example, a portion of the light entry surface or the light exit surface of the lens. As a result, it can serve, for example, to soften the light/dark border, or, respectively, for a targeted adjustment of the sharpness, or the course of the gradient, respectively, of the light/dark border. Alternatively, this optical surface 1 can also serve to illuminate overhead traffic signs.

(6) A portion of the optical surface 1 is depicted in FIG. 1, wherein a dish-shaped micro-lens element 3 is formed on a base surface 2 of the optical surface 1. The micro-lens element 3 has a central main emission surface 4 and an annular subsidiary emission surface 5 adjoining it. The central main emission surface 4 has a contour, corresponding to a contour of the base surface 2 displaced in the normal direction N. The central main emission surface 4, which can be designed, for example, as a flat plateau, is thus disposed, displaced parallel to the base surface 2 of the optical surface 1 disposed in the region of the micro-lens elements 3. When the base surface 2 is curved in this region, then the central main emission surface 4 is likewise curved to the same, or nearly the same, extent. When the base surface 2 is flat in this region—as in FIG. 1—the central main emission surface 4 is likewise flat. The central main emission surface 4 thus runs in a direction nearly identical to, or following the contour of the base surface 2 of the optical surface 1 in the region of these micro-lens elements 3. The light passing through the central main emission surface 4 is thus deflected in the main direction H to the same extent that it is deflected by the base surface 2 of the optical surface 1 in the main direction H when there are no micro-lens elements 3. If the contour of the base surface 2 is flat in the region of the micro-lens elements 3—as depicted in FIG. 1—the light is emitted in the main direction H by the central main emission surface 4, as well as by the base surface 2 disposed adjacent to the micro-lens element 3.

(7) A diffusion of the light in relation to the main direction H in the diffusion direction S is caused by the subsidiary emission surface 5, designed as an angled surface, which adjoins the central main emission surface 4, preferably aligned therewith, at an angle α, and extends as far as the base surface 2 of the optical surface 1.

(8) The micro-lens element 3 is defined by a spacing h of the central main emission surface 4 to the base surface 3, as well as by the angle α, at which the subsidiary emission surface 5 adjoins the central main emission surface 4 in the direction of the base surface 2. When these parameters are defined, a radius R for a boundary surface 6 of the micro-lens element 3 in relation to the base surface 2 of the optical surface 1 is obtained, depending on a curvature of the main emission surface 4. The spacing h between the central main emission surface 4 and the base surface 2 can lie in a range of 0.001 mm to 0.15 mm. The angle cc can lie in a range of 70° to 89.9°. A first example of the dimensions for the micro-lens elements 3, which are disposed in an arbitrary grid on a light exit side of the optical surface 1 designed as a lens, is given below:

(9) TABLE-US-00001 Parameter from to particularly advantageous here α/° 89 89.9 89.35 H/mm 0.001 0.01 0.003 R/mm <2 0.35

(10) Alternatively, the micro-lens elements 3 can also be disposed in the manner of a grid, preferably distributed evenly on a light entry side or light exit side of the optical surface 1 designed as a lens, with the following parameters:

(11) TABLE-US-00002 Parameter from to particularly advantageous here α/° 74 85 80 H/mm 0.010 0.15 0.1 R/mm <2 0.9

(12) In FIG. 2, numerous identical micro-lens elements 3′ are depicted, distributed evenly on the optical surface 1, wherein, by way of example, an enlargement of one of the micro-lens elements 3′ is depicted in cross-section. From this it is visible that a central main emission surface 4′ of the micro-lens element 3′ is curved to nearly, or exactly, the same extent as the base surface 2′ of the optical surface 1′. A subsidiary emission surface 5′ adjoins the central main emission surface 4′ in a continuous manner, and enables a spreading of the light beams at an angle γ. The micro-lens element 3′ is designed as a lens in this embodiment.

(13) It is to be understood that the base surface 2, 2′ of the optical surface 1, 1′ can be designed to be flat and/or convex, or conforming to a freeform surface.

(14) The micro-lens elements 3, 3′ are preferably evenly distributed over the entire base surface 2, 2′ of the optical surface 1, or in only a portion of the base surface 2, 2′ of the optical surface 1. The course of the gradient of the light in the light/dark border, for example, can be controlled by the number and/or the size of the micro-lens elements 3, 3′ in relation to the base surface 2, 2′ of the optical surface 1.

(15) The optical surface 1 can be made of glass or plastic materials, and is designed such that it is transparent.

LIST OF REFERENCE SYMBOLS

(16) 1, 1′ optical surface 2, 2′ base surface 3, 3′ micro-lens elements 4, 4′ central main emission surface 5, 5′ subsidiary emission surface 6 boundary surface h spacing H main direction S diffusion direction N normal direction R radius α angle