Lighting fitting with a diffusser

• US 6,447,133 B1
• Filed: 08/22/1997
• Issued: 09/10/2002
• Est. Priority Date: 10/19/1995
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Eschke, Bernd, Flohr, Heinrich, Vogt, Siegfried
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Curtis, Craig
• Application Number:
  US08/849,897
• Time in Patent Office: 1,845 Days
• Field of Search: 349/65, 362/31, 362/307, 362/311, 362/235, 362/330, 362/331, 362/355, 362/489
• US Class Current: 362/629
• CPC Class Codes: F21V 2200/30 of light guides doped with fluorescent agents
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide

Abstract

An illumination member with a diffuser in which spheres or particles having a different refractive index compared to the diffuser are distributed. The luminance on the output face of the diffuser can be controlled with the number, size and homogeneity of the diffused spheres or particles. A suitable illumination device can set the luminance to bright or dark depending on how it is operated. One preferred application is the illumination of liquid crystal displays or measuring devices in a motor vehicle.

Claims

1. An illumination member, comprising:

a diffuser having an output face, the diffuser receiving light from at least one light source and transmitting the light to the output face, the diffuser including elements having high light-transmission properties, wherein the elements transmit the light received from the at least one light source to the output face as a function of at least one of a geometry of the output face, a number of the elements, a size of the elements, and a homogeneity of the elements in the diffuser; and

a reflector positioned on a lateral surface of the diffuser.

2. The illumination member according to claim 1, wherein the diffuser further includes a reflector positioned on a surface of the diffuser different from the output face.

3. The illumination member according to claim 1, wherein the elements include a plurality of transparent spheres and transparent particles having a first refractive index, and wherein the diffuser has a second refractive index being different from the first refractive index.

4. The illumination member according to claim 1, wherein the at least one light source includes at least one of a lamp, a tube, and a light-emitting diode.

5. The illumination member according to claim 1, wherein the at least one light source is arranged on a face of the diffuser.

6. The illumination member according to claim 1, further comprising:

a deflecting mirror arranged on a face of the diffuser.

7. The illumination member according to claim 1, wherein the illumination member illuminates one of a display, a control panel, and a symbol.

8. The illumination member according to claim 1, wherein the illumination member is used in a motor vehicle display.

9. The illumination member according to claim 1, wherein the elements output the light as a function of the geometry of the output face.

10. The illumination member according to claim 1, wherein the elements output the light as a function of the number of the elements.

11. The illumination member according to claim 1, wherein the elements output the light as a function of the size of the elements.

12. The illumination member according to claim 1 wherein the elements output the light as a function of the homogeneity of the elements in the diffuser.

13. The illumination member according to claim 1, wherein the at least one light source is a plurality of light sources positioned at the lateral surface of the diffuser.

14. The illumination member according to claim 1, wherein the diffuser has a thickness of about 3 millimeters.

15. The illumination member according to claim 7, wherein at least one of the display and the control panel includes a transmissive liquid crystal display.

16. The illumination member according to claim 7 further comprising:

a control unit for increasing a light intensity of the at least one light source for a predetermined time period if at least one of the display, the control panel, and a sensor is pressed.

17. The illumination member according to claim 8, wherein the illumination member is used in a car radio.

18. An illumination member, comprising:

a diffuser having an output face, the diffuser receiving light from at least one light source and transmitting the light to the output face, the diffuser including elements having high light-transmission properties, wherein the elements transmit the light received from the at least one light source to the output face as a function of at least one of a geometry of the output face, a number of the elements, a size of the elements, and a homogeneity of the elements in the diffuser, and

a reflector positioned on a lateral surface of the diffuser;

wherein the elements of the diffuser comprise a plurality of transparent particles, and wherein a diffusion doping level d is linearly and inversely proportional to a light decoupling length l within a scattering value region defined at least by a first value pair and a second value pair, said first value pair having a first d value and a first l value, and said second value pair having a second d value and a second l value.

19. An illumination member, comprising:

a diffuser having an output face, the diffuser receiving light from at least one light source and transmitting the light to the output face, the diffuser including elements having high light-transmission properties, wherein the elements transmit the light received from the at least one light source to the output face as a function of at least one of a geometry of the output face, a number of the elements, a size of the elements, and a homogeneity of the elements in the diffuser, wherein the elements of the diffuser comprise a plurality of transparent particles, and wherein a diffusion doping level d is linearly and inversely proportional to a light decoupling length l within a scattering value region defined at least by a first value pair and a second value pair, said first value pair having a first d value and a first l value, and said second value pair having a second d value and a second l value.

20. The illumination member according to claim 19 wherein said first d value is between approximately 5.25% and 4.35%, said second d value is approximately 1%, said first l value is approximately 10mm, and said second l value is between approximately 85 mm and 105 mm.

21. The illumination member according to claim 19 wherein said scattering value region is further defined by a third value pair and a fourth value pair, and wherein said first d value is approximately 5.25%, said second d value is approximately 1%, said first l value is approximately 10 mm, said second l value is approximately 105 mm, said third value pair having a third d value of approximately 4.35% and a third l value of approximately 10 mm, and said fourth value pair having a fourth d value of approximately 1% and a fourth l value of approximately 85 mm.

22. An illumination member, comprising:

a diffuser having an output face, the diffuser receiving light from at least one light source and transmitting the light to the output face, the diffuser including elements having high light-transmission properties, wherein the elements transmit the light received from the at least one light source to the output face as a function of a homogeneity of the elements in the diffuser and at least one of a geometry of the output face, a number of the elements and a size of the elements.

23. The illumination member according to claim 22, wherein the at least one light source is a plurality of light sources positioned at a lateral surface of the diffuser.

24. The illumination member according to claim 22, wherein the diffuser has a thickness of about 3 millimeters.

25. The illumination member according to claim 23, wherein the plurality of light sources are disposed at least one lateral edge of the illumination member.