Backlighting device

1. A backlighting device, comprising:

a plurality of semiconductor light sources arranged in a plane and serving for generating light radiation; and

at least one side wall arranged laterally with respect to the semiconductor light sources, where the side wall is inclined with respect to the plane predefined by the semiconductor light sources, and wherein the at least one side wall is retroreflective at a side which can be irradiated with light radiation of the semiconductor light sources;

wherein the at least one retroreflective side wall is designed to reflect back more than 50% of an incident light radiation in a predefined angle range in the direction of the incident light radiation.

2. The backlighting device as claimed in claim 1 ,

wherein the inclined and retroreflective side wall is part of a frame extending around the semiconductor light sources, and wherein the frame has further side walls.

3. The backlighting device as claimed in claim 2 ,

wherein the frame is rectangular.

4. The backlighting device as claimed in claim 2 ,

wherein at least one of the further side walls of the frame is inclined and retroreflective.

5. The backlighting device as claimed in claim 1 ,

wherein the at least one retroreflective side wall is designed to reflect back the incident light radiation in an angle range beginning from an angle of more than 0° relative to a normal predefined by the at least one retroreflective side wall.

6. The backlighting device as claimed in claim 1 ,

wherein the at least one retroreflective side wall has a retroreflective structure, and

wherein the retroreflective structure comprises at least one of the following:

an arrangement of microspheres; a microlens arrangement; an arrangement of corner reflectors; an arrangement of inverted cones; an arrangement of inverted truncated cones.

7. The backlighting device as claimed in claim 1 ,

wherein the at least one retroreflective side wall has a retroreflective structure, and

wherein structure elements of the retroreflective structure are tilted with respect to a normal predefined by the at least one retroreflective side wall.

8. The backlighting device as claimed in claim 7 , wherein the structure elements of the retroreflective structure are tilted in the direction of the incident light radiation.

9. The backlighting device as claimed in claim 1 ,

wherein the semiconductor light sources have an optical unit.

10. The backlighting device as claimed in claim 9 ,

wherein the optical unit is a lens.

11. The backlighting device as claimed in claim 1 ,

wherein the semiconductor light sources have a spread emission characteristic with a light emission taking place toward the side.

12. The backlighting device as claimed in claim 1 , comprising an illumination surface, wherein the plane predefined by the semiconductor light sources is arranged in parallel to the illumination surface.

13. The backlighting device as claimed in claim 1 , wherein the at least one retroreflective side wall is adapted to diffusely reflect a part of the incident light radiation.

14. The backlighting device as claimed in claim 1 ,

wherein the at least one retroreflective side wall has a retroreflective structure,

wherein the retroreflective structure comprises a transparent layer having partial curved surfaces at a front side and having partial curved surfaces at a rear side of the transparent layer.

15. The backlighting device as claimed in claim 14 ,

wherein the transparent layer has a biconvex configuration, wherein the front side and the rear side of the transparent layer are each curved outward.

16. The backlighting device as claimed in claim 14 ,

wherein the transparent layer has a concavely curved partial surface on the front side and a convexly curved partial surface on the rear side.

17. The backlighting device as claimed in claim 1 ,

wherein the at least one retroreflective side wall is designed to reflect back a large part of the incident light radiation in the predefined angle range in the direction of the incident light radiation.

18. An apparatus, comprising a backlighting device and a further device, which can be irradiated with light radiation of the backlighting device

the backlighting device comprising:

a plurality of semiconductor light sources arranged in a plane and serving for generating light radiation; and

at least one side wall arranged laterally with respect to the semiconductor light sources, where the side wall is inclined with respect to the plane predefined by the semiconductor light sources, and wherein the side wall is retroreflective at a side which can be irradiated with light radiation of the semiconductor light sources;

wherein the at least one retroreflective side wall is designed to reflect back more than 50% of an incident light radiation in a predefined angle range in the direction of the incident light radiation.

19. A backlighting device, comprising:

an illumination surface,

a plurality of semiconductor light sources arranged in a plane and serving for generating light radiation, wherein the plane predefined by the semiconductor light sources is arranged in parallel with respect to the illumination surface; and

at least one side wall arranged laterally with respect to the semiconductor light sources, wherein the side wall is inclined with respect to the plane predefined by the semiconductor light sources and is inclined with respect to the illumination surface, and wherein the side wall is retroreflective at a side which can be irradiated with light radiation of the semiconductor light sources;

wherein the at least one retroreflective side wall is designed to reflect back more than 50% of an incident light radiation in a predefined angle range in the direction of the incident light radiation.

20. The backlighting device as claimed in claim 19 , wherein part of the incident light radiation is additionally diffusively reflected at the at least one retroreflective side wall.