Lighting device for vehicles for generating two lighting functions with two light sources, a lens and a flat light guide

Abstract

Lighting device with a first lighting unit (1) comprising a first light source (3) and a first optical element (4) arranged upstream of the first light source in the main emission direction (H) for generating a first light function, and with an adjacent second lighting unit (2) comprising a second light source (9) and a second optical element (10) arranged upstream of the first light source in the main emission direction (H) for generating a second light function, wherein the first optical element (4) arranged upstream of the first light source (3) in the main emission direction (H) is designed as a flat light guide with a narrow-sided light coupling surface (5), a narrow-sided light coupling surface (6), and opposite flat sides (7) connecting the light coupling surface (5) and the light coupling surface (6), wherein the flat sides (7) of the flat light guide extend in the main emission direction (H) of the first lighting unit (1), characterized in that- that the second optical element (10) is designed as a lens with a light-entry surface (12) facing the second light source (9) and a light-emission surface (14) facing away from the second light source (9), - that the light-entry surface (5) of the flat light guide of the first lighting unit (1) is arranged at a distance (a) from the first light source (3), - that a first part (L1) of the light emitted by the first light source (3) is coupled into the light-entry surface (5) of the flat light guide of the first optical element (4) and, after exiting the flat light guide of the first optical element (4), forms a main light beam (HL), and - that a second part (L1') of the light emitted by the first light source (3) strikes the light-entry surface (12) of the lens (10) of the second lighting unit (2) directly, is coupled into the lens (10), and, after exiting the lens (10), forms a side light beam (SL) forms.

Description

[0001] The invention relates to a lighting device for vehicles with a first lighting unit comprising a first light source and a first optical element positioned in front of it in the main direction of emission for generating a first light function, and with a second lighting unit comprising a second light source and a second optical element positioned in front of it in the main direction of emission for generating a second light function.

[0002] From DE 102 05 048 A1, a lighting device for vehicles is known which has at least two lighting units with different lighting functions. A first lighting unit has a light source and an optical element with a curved side surface, so that a beam of light is emitted laterally at a relatively large angle to generate a cornering light function. Adjacent to this first lighting unit is a second lighting unit with a light source and a reflector as a second optical element, which serves to generate a flashing light function. The known lighting device allows for a space-saving arrangement of several lighting units.

[0003] To generate daytime running lights, flat light guides are now used as an optical element positioned in front of a light source. These flat light guides have a narrow light coupling area and a narrow light coupling area. Opposing flat surfaces extend between the light coupling and light coupling areas, along which the coupled light is directed towards the light coupling area by total internal reflection. A disadvantage of such a daytime running light unit is that, due to the narrow light coupling area, the flat light guide must be relatively long to meet the legal requirements regarding the minimum illuminated area of ​​the light function.

[0004] The object of the present invention is therefore to further develop a lighting device for vehicles in such a way that the illuminating area of ​​a lighting unit is increased in a simple manner while saving space.

[0005] To solve this problem, the invention, in conjunction with the preamble of claim 1, is characterized in that the first optical element, arranged in the main emission direction in front of the first light source, is designed as a flat light guide with a narrow-sided light coupling surface, a narrow-sided light emission surface, and opposite flat sides connecting the light coupling surface and the light emission surface, and that the light coupling surface of the flat light guide is arranged at such a distance to the first light source that a side light beam emitted by the first light source strikes the second optical element to illuminate it.

[0006] The particular advantage of the invention lies in the fact that, in a space-saving manner, an optical element of an adjacent second lighting unit is used to illuminate a first lighting unit. A light source associated with the optical element of the first lighting unit can emit a partial beam of light laterally in such a way that it does not strike the first optical element, but rather a second optical element of the adjacent second lighting unit. If the second lighting unit is in a non-operating state, the second optical element is illuminated by the laterally emitted partial beam of light (side beam) from the first light source and can serve to increase the illuminated area of ​​the actual first lighting unit. According to the invention, a main beam of light is thus always coupled into the first optical element located in front of the first light source, and a side beam of light is coupled into the second optical element associated with the second lighting unit.

[0007] According to a preferred embodiment of the invention, the second optical element is arranged at such a distance from the second light source of the second lighting unit that the side light beam of the first light source strikes a light-intake side of the second optical element. The angle of incidence of the side light beam onto the light-intake surface of the second optical element can be relatively large. It is sufficient if the second optical element also illuminates without using light rays to illuminate a foreground area. The illumination of the second optical element is just sufficient to produce an ambient illuminating effect that is measurable and meets the legal requirements regarding the minimum illuminating area of ​​the first lighting function.

[0008] According to a further development of the invention, the first optical element has a flattened surface on a side facing the second optical element, so that a light path for the side light beam is opened to the second optical element. Advantageously, this allows a side light beam to be diverted in a simple manner, with a main light beam entering the first optical element and being coupled out at the light output surface of the same according to a predetermined light distribution.

[0009] According to a further development of the invention, an optical partition is arranged between the first optical element and the second optical element, so that there is no coupling or interaction in an area between the light entry side and the light exit side between the first optical element and the second optical element.

[0010] According to a further development of the invention, the second optical element is designed as a lens which, in conjunction with the second light source, emits a primary light function, such as a low beam function. If the first light function is used as a secondary light function, this results in a useful functional combination in which the second optical element has a dual function. When the second light source is switched on and the first light source is switched off, it serves to generate the primary light function. When the second light source is switched off and the first light source is switched on, it serves to generate the secondary light function.

[0011] According to a further development of the invention, the second optical element has a transverse extent perpendicular to the partition wall that is at least three times larger than the transverse extent of the flat light guide. This ensures that a sufficiently large illumination area is provided for the first lighting function.

[0012] According to a further development of the invention, the first light source and the second light source are arranged on a common plane. For example, the two light sources can be arranged on a common circuit board, which reduces costs.

[0013] Further advantages of the invention will become apparent from the further dependent claims.

[0014] An embodiment of the invention is explained in more detail below with reference to the drawing.

[0015] It shows:

[0016] Figure a schematic top view of a lighting device according to the invention.

[0017] A lighting device according to the invention can be used in the front or rear area of ​​a vehicle. In the present embodiment, the lighting device comprises a first lighting unit arranged in a housing (not shown). 1 as well as a second lighting unit 2 The lighting device is mounted as a headlight in the front area of ​​the vehicle.

[0018] The first lighting unit 1 serves to generate a secondary light function, for example a daytime running light function, and features as the first light source 3 at least one light-emitting diode (LED). The LED light source 3 is a first optical element in the main emission direction H 4 A flat optical fiber is positioned in front of it. 4It is narrow in the main emission direction H. It points towards one of the first light sources. 3 a narrow-sided light coupling surface on the facing side 5 and on one of the first light sources 3 A light extraction surface on the opposite side 6 on. Between the light coupling surface 5 and the light output surface 6 opposite flat sides extend 7 relatively large dimension, on whose light rays L1 one of the first light source 3 emitted main light beam HL in the direction of the light coupling surface 6 are transmitted through total internal reflection.

[0019] A longitudinal median plane 8 the first lighting unit 1 runs parallel to the flat sides 7 of the flat light guide 4 In the longitudinal mid-plane 8 the main beam direction H of the first lighting unit runs 1 .

[0020] Adjacent to the first light unit 1 , namely at a distance along a normal to the flat sides 7 , is the second lighting unit 2 arranged to provide a second light source 9 and one in the main emission direction H in front of the second light source 9 arranged second optical element 10 The second light source 9 is – like the first light source 3 – designed as an LED light source. The second optical element 10 is designed as a lens, preferably as a plano-convex lens. The plano-convex lens 10 is not rotationally symmetric about an optical axis 11 the second lighting unit 2 arranged. The lens 10 has a flat light-entry surface 12 on, which are at an axial distance b to the second light source 9 or one of the second light source 9 load-bearing circuit board13 is arranged. Alternatively, the light entry surface can be 12 They may also be convex or concave shaped. On one of the second light sources 9 far side of the lens 10 A convex light-emitting surface runs along it. 14 , at the second light source 9 The emitted light rays L2, used to generate a primary light function, for example a low beam function, exit in the main emission direction H under refraction. The light exit surface 14 is designed as a freeform surface which can, for example, have optical elements.

[0021] The lens 10 exhibits a transverse extent c2 that is at least three times larger than a transverse extent c1 of the flat optical fiber. 4 .

[0022] As the first light sources 3 the first lighting unit 1 are preferably a plurality of LED light sources 3provided for, which are positioned perpendicular to the plane of the drawing at a predetermined distance on a narrow circuit board 15 extend. The length of the circuit board 15 corresponds to a length of the flat light guide 4 The length of the flat optical fiber running perpendicular to the plane of the drawing. 4 is not sufficient to ensure that the dimension of the light extraction area 6 exceeds the specified minimum illumination area of ​​25 cm according to ECE regulations.

[0023] So that the minimum illuminated area of ​​the first lighting unit 1 When generating a daytime running light function, the first optical element 4 on one of the adjacent second optical elements 10 a flattening on the facing side 16 up, so that one from the first light source 3 emitted side light beam SL with light rays L1' in the direction of the second optical element 10is emitted or "branched off". Preferably, the light rays L1' strike the light-initiating surface. 12 of the second optical element 10 .

[0024] A distance a between the light coupling surface 5 of the flat light guide 4 and the first light source 3 or the circuit board 15 is chosen in such a way that, preferably, the flattening is utilized. 16 the side light beam SL onto the second optical element 10 it hits and causes it to illuminate towards the main direction of emission H. The proportion of the side light beam SL to the total light emitted by the first light source. 3 The emitted light beam can be so small that the lens has an ambient-illuminating effect. 10This occurs without the side light beam SL contributing to the generation of a light distribution. In this case, an illuminated surface appears to an observer, the dimensions of which correspond to the projection of the light-emitting surface. 14 the lens 10 corresponds to a plane running perpendicular to the main radiation direction H.

[0025] To generate the daytime running light function, only the first light source is required. 3 , but not the second light source 9 switched on. In this operating state, a high-intensity main light distribution HL is produced by means of the first optical element. 4 and a low-intensity side light distribution SL by means of the second optical element 10 Emitted in the main radiation direction H.

[0026] To generate the main light distribution, the first light source 3 switched off, while the second light source 9is switched on. Only via the second optical element. 10 The main light distribution AL is emitted.

[0027] To avoid an interaction between the two light functions "main light" and "side light", a separation is required between the first lighting unit. 1 and the second lighting unit 2 a partition wall 17 arranged, which is not transparent. The partition 17 extends in an area between the light entry surface 12 of the second optical element 10 up to a light extraction surface 6 of the first optical element 4 , preferably via the light extraction surface 6 out.

[0028] The first light sources 3 as well as the second light source 9 are positioned in a common plane of extension E, which is perpendicular to the main emission direction H. For example, the first light sources can be 3and the second light source 9 They can be arranged on a common circuit board. Alternatively, the light sources can be 3 , 9 They may also be arranged in different extension planes offset from the main radiation direction (H).

[0029] According to an alternative embodiment of the invention (not shown), more than two lighting units can also be arranged side by side, wherein a side light beam is branched off from at least one lighting unit in at least one direction.

[0030] In the present embodiment, the light coupling surface 5 of the first optical element 4 one of the first light sources 3 associated recess 18 on, for improved light introduction into the flat light guide 5 .

[0031] The optical elements 4 , 10are made of a transparent material, preferably a transparent plastic material. Reference symbol list 1. Lighting unit 2 2. Lighting unit 3 1. Light source 4 1. Optical element 5 Light coupling area 6 Light extraction area 7 flat pages 8 Longitudinal median plane 9 2. Light source 10 2. Optical element 11 optical axis 12 Light entry area 13 Circuit board 14 Light emission area 15 circuit boards 16 Flattening 17 Partition wall 18. Groove H Main radiation direction E Extension direction L1, L1', L2 Light rays HL main light beam SL side light beam c2, c1 transverse extension a distance b axial distance AL low beam distribution QUOTES INCLUDED IN THE DESCRIPTION

[0032] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0033] DE 10205048 A1

[0002]

Claims

[1] Lighting device comprising a first lighting unit containing a first light source and a first optical element positioned in front of it in the main direction of emission for generating a first light function, and comprising a second lighting unit comprising a second light source and a second optical element positioned in front of it in the main direction of emission for generating a second light function, characterized by that in the main direction of radiation (H) in front of the first light source ( 3 ) arranged first optical element ( 4 ) as a flat light guide with a narrow-sided light coupling surface ( 5 ), with a narrow-sided light extraction surface ( 6 ) and with the light coupling surface ( 5 ) and the light output surface ( 6 ) connecting opposite flat sides ( 7 ) is formed, and that the light coupling surface ( 5 ) of the flat light guide ( 4) at such a distance (a) to the first light source ( 3 ) is arranged so that one of the first light source ( 4 ) emitted side light beam (SL) onto the second optical element ( 10 ) to illuminate the same. [2] Lighting device according to claim 1, characterized by that the second optical element ( 10 ) at such a distance (b) to the second light source ( 9 ) is arranged so that the side light beam (SL) of the first light source ( 3 ) on a light-entry side ( 12 ) of the second optical element ( 10 ) meets. [3] Lighting device according to claim 1 or 2, characterized by that the first optical element ( 4 ) on one of the second optical elements ( 10 ) facing side a flattening ( 16 ) has to expose the light path to the second optical element ( 10 ). [4] Lighting device according to any one of claims 1 to 3, characterized by that between the first optical element ( 4 ) and the second optical element ( 10 ) a partition wall ( 17 ) is arranged. [5] Lighting device according to any one of claims 1 to 4, characterized by that the second optical element ( 10 ) is designed as a lens, by means of which, in the switched-on state of the second light source ( 9 ) a main light function (AL) can be emitted. [6] Lighting device according to any one of claims 1 to 5, characterized by that the second optical element ( 10 ) a transverse extension (c2) perpendicular to the partition wall ( 17 ) exhibits a cross-sectional area (c1) of the flat optical fiber ( 4 ). [7] Lighting device according to any one of claims 1 to 6, characterized by that the first light source ( 3 ) and the second light source ( 9) each designed as LED light sources and arranged in a common extension plane (E) or in different extension planes offset in the main emission direction (H). [8] Lighting device according to any one of claims 1 to 7, characterized by that the first light source ( 3 ) is controlled in such a way that the first lighting unit ( 1 ) emits a secondary light function. [9] Lighting device according to any one of claims 1 to 8, characterized by that the first lighting unit ( 1 ) and the second lighting unit ( 2 ) are arranged in a common housing. [10] Lighting device according to any one of claims 1 to 9, characterized by that the light-emitting surface ( 14 ) of the second optical element ( 10 ) is designed in such a way that, in conjunction with the light output surface ( 6 ) of the first lighting unit ( 1) a minimum illuminating area is fulfilled for the first lighting function.