Illumination device for vehicles

Abstract

An illumination device for vehicles, in particular rear light, with a light-emitting unit to generate a predetermined light function. The device comprises a plurality of light sources and an optical unit. The optical unit comprises a light guide with means for the deflection of the light coupled in the same, and a retroreflective unit to generate a retroreflective function. The light guide is designed as a low-profile light guide, which is arranged in the main radiation direction in front of the retroreflective unit. The means for deflecting the light are distributed on or in the low-profile light guide such that the first light beam emitted from the light source and coupled into a narrow side of the low-profile light guide is coupled out at a front flat side of the low-profile light guide to produce the predetermined light function. A second light beam coming from the outside passes the front flat side and a rear flat side of the low-profile light guide and is incident on the retroreflective unit and is reflected by it back through the rear flat side and the front flat side of the low-profile light guide in the main radiation direction to generate the retroreflective function.

Claims

1. An illumination device for vehicles comprising: a light-emitting unit to generate a predetermined light function, said light-emitting unit comprising: a plurality of light sources; an optical unit including a light guide having means for deflecting light launched into the same light from the light source; a retroreflective unit for producing a retroreflective function; wherein the light guide is formed as a low-profile light guide which is arranged in the main radiation direction in front of the retroreflective unit, and wherein the means for deflection of the light are distributed at and/or in the low-profile light guide such that: a first light beam (L1) emitted by the light source and launched into a narrow side of the low-profile light guide is coupled out at a front flat side of the low-profile light guide to produce the predetermined light function, and a second light beam (L2) irradiating from the outside passes through the front flat side and a rear flat side of the low-profile light guide impinges on the retroreflective unit and is reflected by the same back through the rear flat side and the front flat side of the low-profile light guide in the main radiation direction for producing the retroreflective function.

2. The illumination device according to claim 1, wherein a number of dispersive optical elements is arranged on the rear flat side of the low-profile light guide as means for deflecting the light (L1) so that the light impinging on the dispersing optical element is reflected toward the front flat side for coupling out on it in the main radiation direction.

3. The illumination device according to claim 2, wherein the dispersive optical element are distributed according to a predetermined pattern over the rear flat side of the low-profile light guide.

4. The illumination device according to claim 2 the dispersive optical elements are distributed over the rear flat side of the low-profile light guide according to a stripe pattern or a chessboard pattern.

5. The illumination device according to claim 2 the dispersive optical elements are applied by erosion or by etching or by laser to the rear flat side of the low-profile light guide.

6. The illumination device according to claim 2 the dispersive optical elements are applied by printing or by painting to the rear flat side of the low-profile light guide.

7. The illumination device according to claim 2 the light sources are arranged on a circuit board, which is equipped with further light sources for producing further light functions.

8. The illumination device according to claim 2 the low-profile light guide is made by injection molding and in that the dispersive optical element with increasing distance to the light input section are arranged in a higher or greater distribution density so that the first light beam (L1) is homogeneously irradiated from the low-profile light guide for producing the light function.

9. The illumination device according to claim 1, wherein dispersing optical particles are distributed in the low-profile light guide as means for deflecting the light (L1).

10. The illumination device according to claim 9, wherein the dispersing optical particles are formed as nanoparticles, which are uniformly distributed in the low-profile light guide.

11. The illumination device according to claim 10, wherein the nanoparticles are arranged in such a concentration in the low-profile light guide that the reflection of the second light beam (L2) through the low-profile light guide is reduced by not more than 30%.

12. The illumination device according to claim 10, wherein the low-profile light guide consists of a first material containing nanoparticles and a nanoparticle-free second material.

13. The illumination device according to claim 12, wherein the low-profile light guide is manufactured by two-component injection molding.

14. The illumination device according to claim 1 the low-profile light guide comprises on the edge side an arcuate light input section having the light input narrow side, and that the narrow side is associated with a plurality of light sources whose optical axes (A) extend in the main radiation direction.

15. The illumination device according to claim 1 the light input section is covered by a diaphragm.

16. The illumination device according to claim 1 wherein the retroreflective unit has a reflecting surface of such a size and in that the low-profile light guide comprises a dispersive optics-free surface of such a size that it corresponds to a minimum reflecting area or that it exceeds the minimum reflecting area.

17. The illumination device according to claim 16 wherein at least one of the low-profile light guide and the reflecting surface are colored red.

18. The illumination device according to claim 16 the flat sides of the low-profile light guide have a greater dimension than the reflecting surface of the retroreflective unit.

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 shows a plan view of an illumination device.

(3) FIG. 2 shows a perspective view of the illumination device without a cover.

(4) FIG. 3 shows a perspective view of the lighting apparatus with a detached diaphragm.

(5) FIG. 4 shows a perspective view of a low-profile light guide, a retroreflective unit arranged behind it, and lateral circuit boards which are equipped with LED light sources, without the housing.

(6) FIG. 5 shows a plan view of the low-profile light guide reflector structure according to FIG. 4.

(7) FIG. 6 shows a rear view of the low-profile light guide.

(8) FIG. 7 shows a section through the low-profile light guide along the section line VII-VII in FIG. 6.

(9) FIG. 8 shows a schematic front view of the illumination device with a low-profile light guide, having a linear light scattering optics structure.

(10) FIG. 9 shows a schematic front view of the illumination device with a light guide surface having a chessboard-like light scattering optics structure.

DETAILED DESCRIPTION OF THE DRAWINGS

(11) An illumination device according to the invention can be used, for example, as a rear light for trucks or trailers. Alternatively, the illumination device can be also used in rear lights of passenger cars.

(12) According to an embodiment of the illumination device according to the FIGS. 1 to 7, a rectangular housing 1 is provided, which has a relatively flat opening. In the opening of the housing 1, there are arranged a light-emitting unit 3 for producing a rear light function as well as a reflector unit 4 in a central region 2. On opposite sides of the light-emitting unit 3 are arranged further light-emitting units with a strip-shaped illuminated panel. A brake light unit 5 for producing a brake light is arranged on a face end of the housing 1. Adjacent to the brake light unit 5 is arranged a flashing light unit 6 for generating a direction indicator. At an opposite face end of the housing 1 is arranged a rear fog lamp unit (7) for generating a fog light, and adjacent thereto is arranged a rear light unit for generating a reversing light. The light-emitting unit 3 to generate the rear light has for spatial radiation thereof a low-profile light guide 9 as a light guide. The low-profile light guide 9 serves at the same time as the optical unit for the light-emitting unit 3.

(13) The low-profile light guide 9 is formed rectangular and has front flat sides 10 arranged in the front in the main radiation direction H of the illumination device, and a rear flat side 11 arranged at the back in the main radiation direction H. On opposite sides, a light input section 12 of the low-profile light guide 9, which is arcuate, joins the flat sides 10, 11. The light input section 12 allows a 90 degree deflection of the low-profile light guide 9 on an edge thereof, so that a first light beam L1 of the light sources 14 can be launched into the low-profile light guide 9 through a narrow side 13 of the low-profile light guide 9 arranged at a free end of the light input section 12, wherein the light sources 14 are arranged in a common plane and have an optical axis A, which extends parallel to the main radiation direction H of the illumination device. As shown particularly in FIG. 4, the light sources 14 assigned to the rear light-emitting unit 3 are arranged in a row R1, R1. The row R1, R1 of the light sources 14 is parallel offset to a row R2 of the light sources 14 for the brake light unit 5, to a row R3 of light sources 4 for the blinking light unit 6, to a row R4 of the light sources 14 for the rear fog light unit 7 and a row R5 of the light sources 14 for the reversing light unit 8. The light sources 14 of the rows R1, R2, R3 are arranged on a first circuit board 15 and the rows R1, R4 and R5 are arranged on a second circuit board 16.

(14) The first circuit board 15 and the second circuit board 16 are set in the housing 1 by engagement with a bottom thereof. In the central region 2 between the first circuit board 15 and the second circuit board 16 is arranged the reflector unit 4, wherein a square housing 17 of the reverse light unit 4 accommodates a triangular reflecting surface 18.

(15) The retroreflective unit 4 has a greater thickness than the printed circuit boards 15, 16. The light input sections 12 of the low-profile light guide 9 have such an arc length that the low-profile light guide 9 covers the retroreflective unit 4 with its front and rear flat sides 10, 11 or is arranged in the main radiation direction H in front of the retroreflective unit 4. In order to distinguish the light-emitting units 3, 5, 6, 7.8 from each other, a covering diaphragm 19 is provided, which has a square opening 20 in the central region and line-shaped openings 21 at opposite ends. The line-shaped openings 21 have reflector segments 22 adapted to the light sources 14 of the brake light unit 5, the flashing light unit 6, the rear fog lamp unit 7 and the reverse light unit.

(16) The diaphragm 19 is connected by fastening means 23 to the housing 1. For this purpose, the housing 1 comprises projecting domes 24, into which can be screwed the fastening means 23 designed as a screw means. On the outside, the illumination device thus formed is closed with a transparent cover plate which is not shown.

(17) As becomes clear in particular from FIGS. 6 and 7, the rear flat side 11 of the low-profile light guide 9 comprises a number of dispersive optical elements 25 as means for deflecting the light L injected via the light input section 12 so that upon incidence of the light conducted within the low-profile light guide 9 after total reflection on the front flat side 10 and the rear flat side 11, the light L1 is deflected toward the front flat side 10 and then is coupled out through the front flat side 10 in the main radiation direction H for producing the rear light function. The dispersive optical elements 25 are arranged in a chessboard pattern 26as schematically illustrated in FIG. 9. The dispersive optical elements 25 are formed as prismatic cuts whose dimension increases with the distance to the light input section 12 up to a median plane M of the low-profile light guide 9. In this way, a light radiation L1 that is uniform over the surface is made possible.

(18) Since the dispersive optical elements 25 are arranged spaced from one another, a dispersive optics-free surface 27 is formed on the rear flat side 11, whichlike the completely dispersive optics-free front flat side 10allows the passage of a second light beam L2. The second light beam L2 enters from the outside through the front flat side 10 and the dispersive optics-free surfaces 27 of the rear flat side 11 of the low-profile light guide 9, strikes the reflecting surface 18 of the retroreflective unit 4, from which it is reflected toward the low-profile light guide 9 so that the second light beam L2 exits through the dispersive optics-free surface 27 of the rear flat side 11 and the front flat side 10 outwards to produce the retroreflective function.

(19) The dispersive optics-free surface 27 of the rear flat side 11 is selected so large that it is equal to or greater than a minimum reflector area. Furthermore, the reflector area 18 of the reflector unit 4 has such a size that it corresponds to the minimum retroreflective area or is greater than it. In this way it is ensured that the legally prescribed minimum reflector area is ensured for the retroreflective function. It is understood that preferably the dimension of the low-profile light guide 9 is greater than the dimension of the retro-reflecting surface 18.

(20) The low-profile light guide 9 is preferably designed as an injection-molded component, wherein the dispersive optical elements 25 are manufactured in one step with the low-profile light guide 9. Preferably, the low-profile light guide 9 and the retro-reflecting surface 18 are colored red.

(21) According to a not shown alternative embodiment of the invention, the dispersive optical elements 25 can also be formed of the same size, wherein the distribution density thereof becomes larger from the light input section 12 toward the median plane M.

(22) According to an alternative embodiment of the invention, the dispersive optical elements 25 can also be applied to the rear flat side 11 of the low-profile light guide 9 by erosion or by etching or by laser.

(23) According to a not shown alternative embodiment of the invention, the dispersive optics element 25 can be applied to the rear flat side 11 of the low-profile light guide 9.

(24) According to a further not shown alternative embodiment of the invention, the means for deflecting the light L1 can be formed by dispersive optical particles, which are arranged within the low-profile light guide 9, i.e., between the front flat side 10 and the rear flat side 11. The distribution of the dispersive optical elements isnot as in the previous embodimentsnot limited to the back flat side 11 of the low-profile light guide 9.

(25) Preferably, the dispersive optical particles are formed as nanoparticles whose dimensions are in the nanometer range. These nanoparticles are preferably uniformly distributed within the low-profile light guide 9. The nanoparticles are arranged within the low-profile light guide 9 in such a concentration that with the reflection of the second light beam L2 by the light guide surface 9 it is reduced not more than by 30%. In this way, the retroreflective function is secured.

(26) It is always assumed that the second light beam L2 passes the light beam L2 transversely to the low-profile light guide 9, wherein it is refracted at the front flat side 10 or the rear flat side 11.

(27) According to a further alternative embodiment of the invention, the light guide may also consist of a first material containing the nanoparticles and a second material that is formed nanoparticle-free. In this way, dispersive optics-free and dispersive optics containing areas of the low-profile light guide can be formed so that, for example, in a longitudinal section of the low-profile light guide there arises a chessboard pattern of the first and second materials. This low-profile light guide can preferably be manufactured by a 2-component injection molding process.

(28) It is understood that the light sources 14 are configured as LED light sources. Alternatively, other semiconductor light sources can be used.

(29) The printed circuit boards 15, 16 are preferably formed as rigid circuit boards.

(30) In FIG. 9 is schematically shown the chessboard pattern 26 of the rear flat side 11 consisting of dispersive optical elements 25 and dispersive optics-free areas 27. In this embodiment, the low-profile light guide 9 can be formed as a plate, wherein the front flat side and the rear flat side are connected together by narrow sides. The light L1 is launched not in the main radiation direction Has is the case in the preceding embodimentsbut rather transverse to the main radiation direction H in the longitudinal direction of the low-profile light guide 9. In FIG. 9, the contour of the reflector unit 4 is sketched in, which is smaller than the low-profile light guide 9. However, the sections of the dispersive optics-free areas 27 overlapping the retroreflector surface 18 are so large that a retroreflective function is ensured.

(31) The same components or component functions of the embodiments are provided with the same reference numerals.

(32) According to an alternative embodiment of the invention according to FIG. 8, the dispersive optics elements 25 are arranged in strips on the rear flat side 11 of the low-profile light guide 9.

(33) If necessary, the dispersive optical elements 25, 25 can be also arranged in a different pattern, for example a checker pattern. The dispersive optical elements themselves can be designed as circular areas, triangular or polygon areas or in another form.

(34) The low-profile light guide interspersed with the nanoparticles appears in optical examination crystal clear or as a slightly diffuse disc with no apparent structure. Upon illumination of the low-profile light guide from the narrow side, the light propagates in the area under total reflection at the front and rear flat sides and is scattered at the nanoparticles so that the entire low-profile light guide is uniformly illuminated. The nanoparticles cause only a very small scattering of the light L2 transmitted transversely to the low-profile light guide so that the retroreflective function is ensured.

(35) The invention enables the space-saving combination of a passive reflecting function with an active light-emitting function. The active light-emitting function can also be used to produce a different light function.

(36) TABLE-US-00001 List of reference numerals 1 Housing 2 Central region 3 Light emitting unit 4 Retroreflective unit 5 Brake light unit 6 Flashing light unit 7 Rear fog light unit 8 Reversing light unit 9 Low-profile light guide 10 Front flat side L1.L2 Light beam 12 Rear flat side A Axis 13 Narrow side M Median plane 14 Light sources H Main radiation direction 15 1. circuit board R1, R1 Row 16 2. circuit board R2, R2 Row 17 Housing R3, R3 Row 18 Retroreflective unit R4, R4 Row 19 Covering diaphragm L Light 20 Square opening 21 Line-shaped openings 22 Reflector segments 23 Attaching means 24 Domes 25, 25 Dispersive optical elements 26 Chessboard pattern 27 Dispersive optics-free area