Light source device with equalized colors split, and method of making same

• US 20070019409A1
• Filed: 07/24/2006
• Published: 01/25/2007
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Nawashiro, Mitsuhiro, Inagaki, Satoshi
• Granted Patent: US 7,556,404 B2
• Time in Patent Office: Days
• US Class Current: 362/231
• CPC Class Codes: F21K 9/69 Details of refractors forming part of the light source
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light source device includes a light emitting diode (LED) device, a lens and a light diffusing layer. The LED device includes an LED chip, which emits light, and a fluorescent, which converts a part of the light from the LED chip. The lens is located on a side of a light emitting face of the LED device. The light diffusing layer is located between the LED device and the lens. An air layer exists between the light diffusing layer and the LED device or between the light diffusing layer and the lens.

Claims

1. A light source device, comprising:

a light emitting diode (LED) device including an LED chip, which emits light, and a fluorescent substance, which converts a part of the light from the LED chip;

a lens located on a side of a light emitting face of the LED device; and

a light diffuser located apart from at least one of the LED device and the lens, to equalize a distribution of the light emitted from the LED chip and the light converted by the florescent substance.

2. The light source device according to claim 1, wherein the light diffuser comprises a light diffusing layer.

3. The light source device according to claim 1, wherein the light diffuser comprises a sheet that includes light diffusing faces on two opposing surfaces thereof.

4. The light source device according to claim 1, wherein the LED chip emits a blue light and the fluorescent substance converts the blue light to a yellow light.

5. The light source device according to claim 1, wherein the light diffuser is adhered to the light emitting face of the LED device in a manner to provide a predetermined distance therebetween.

6. The light source device according to claim 1, wherein the light diffuser is adhered to a light receiving face of the lens in a manner to provide a predetermined distance therebetween.

7. The light source device according to claim 5, wherein an adhesive agent adheres the light diffuser to the LED device, and wherein a thickness of the adhesive agent is such that the predetermined distance is less than approximately 0.2 mm.

8. The light source device according to claim 5, wherein an adhesive agent adheres the light diffuser to the lens, and wherein a thickness of the adhesive agent is such that the predetermined distance is less than approximately 0.2 mm.

15. An assembly comprising the light source device of claim 1.

9. A light source device, comprising:

a light emitting diode (LED) device including an LED chip, which emits light, and a fluorescent material, which converts a part of the light from the LED chip; and

a light diffusing layer located above a light emitting face of the LED device;

wherein the light diffusing layer is adhered to the LED device at a predetermined distance away from the light emitting face, to equalize a distribution of the light emitted from the LED chip and the converted light.

10. The light source device according to claim 9, wherein the light diffusing layer comprises a plurality of light diffusing surfaces.

11. The light source device according to claim 9, wherein the light diffusing layer comprises a sheet that includes two light diffusing faces on opposite surfaces thereof.

12. The light source device according to claim 9, wherein the LED chip emits a blue light and the fluorescent material converts the blue light to a yellow fluorescence.

13. The light source device according to claim 9, wherein an adhesive agent adheres the light diffusing layer to the LED device, such that a distance between the light diffusing layer and the LED device is less than approximately 0.2 mm.

14. The light source device according to claim 9, wherein the distance between the light diffusing layer and the LED device is less than approximately 0.2 mm.

16. A light source device, comprising:

means for emitting a light at a first frequency and a light at a second frequency, the light of the second frequency resulting from a conversion of a portion of the light at the first frequency;

means for focusing the emitted light at the first and second frequencies; and

means for equalizing a distribution of the lights at the first and second frequencies prior to entering into the means for focusing.

17. A method of manufacturing a light source device that has an equalized distribution of two or more colors of light emitted therefrom, the method comprising:

mounting a light emitting diode assembly, the assembly including a light emitting diode that emits a light at a first frequency and a fluorescent material that converts a portion of the light at the first frequency into a light at a second frequency and emits the light at the second frequency; and

mounting a focusing lens apart from a light emitting face of the light emitting diode assembly,

wherein one of the light emitting diode assembly and the focusing lens has attached thereto a light diffuser that equalizes the distribution of two or more colors by being attached in such manner as to provide a predetermined separation gap between the light diffuser and one of a light emitting face of the light emitting diode assembly and a light receiving face of the focusing lens.

18. The method of claim 17, wherein the light diffuser comprises a sheet of material having an irregular surface thereon, the method further comprising:

adhering, with an adhesive having a thickness that provides the predetermined separation gap, the sheet of material to one of the light emitting face of the light emitting diode assembly and the light receiving face of the focusing lens.

19. The method of claim 18, wherein the predetermined separation gap is in a range of approximately 0.01 mm to approximately 0.2 mm.

20. The method of claim 18, wherein the sheet of material has an irregular surface on each of two opposing sides of said sheet.