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

• US 7,556,404 B2
• Filed: 07/24/2006
• Issued: 07/07/2009
• 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
• Primary Examiner(s): Negron; Ismael
• Assistant Examiner(s): Crowe; David R
• Application Number:
  US11/491,489
• Publication Number:
  US 20070019409A1
• Time in Patent Office: 1,079 Days
• Field of Search: 362/606, 362/293, 362/231, 362/235, 362/84, 362/800, 362/555, 362/558, 362/260, 257/98, 257/100, 257/79, 313/512, 313/485
• US Class Current: 362/293
• 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 a blue 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 diffusing sheet located between the LED device and the lens and located apart from at least one of the LED device and the lens to provide an air gap therebetween, said air gap assisting to equalize a distribution of the light emitted from the LED chip and the light converted by the florescent substance,

wherein a periphery of the light diffusing sheet is adhered to the light emitting face of the LED device by an adhesive agent in a manner to provide the air gap therebetween, and

wherein a thickness of the adhesive agent is such that the air gap is less than approximately 0.2 mm.

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

3. The light source device according to claim 1,

wherein the light diffusing sheet includes light diffusing faces on two opposing surfaces thereof.

4. The light source device according to claim 1,

wherein the fluorescent substance converts the blue light to a yellow light.

5. The light source device of claim 1, further comprising a reflector as a component of the LED device,

wherein the light diffusing sheet is adhered to an upper surface of a periphery of the reflector by the adhesive agent.

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

7. A light source device, comprising:

a light emitting diode (LED) device including an LED chip, which emits a blue 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 diffusing sheet located between the LED device and the lens and located apart from at least one of the LED device and the lens to provide an air gap therebetween, said air gap assisting to equalize a distribution of the light emitted from the LED chip and the light converted by the fluorescent substance,

wherein a periphery of the light diffusing sheet is adhered to a light receiving face of the lens by an adhesive agent in a manner to provide the air gap therebetween, and

wherein a thickness of the adhesive agent is such that the air gap is less than approximately 0.2 mm.

8. The light source device according to claim 7,

wherein the light diffusing sheet comprises a plurality of light diffusing surfaces.

9. The light source device according to claim 7,

wherein the light diffusing sheet includes two light diffusing faces on opposite surfaces thereof.

10. The light source device according to claim 7,

wherein the fluorescent material converts the blue light to a yellow fluorescence.

11. The light source device according to claim 7,

wherein the distance between the light diffusing sheet and the LED device is less than approximately 0.2 mm.

12. The light source device of claim 7,

wherein the light diffusing sheet covers a center part of the light receiving face of the lens through an air layer.

13. 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;

means for diffusing said emitted light at the first and second frequencies, said means for diffusing located between said means for emitting and said means for focusing; and

means, including an air gap, for equalizing a distribution of the lights at the first and second frequencies prior to entering into the means for focusing,

wherein the means for diffusing is adhered, by an adhesive agent applied to a periphery of the means for diffusing said emitted light, to a light receiving face of the means for focusing the emitted light at the first and second frequencies in a manner to provide a predetermined distance therebetween to provide said air gap, wherein a thickness of the adhesive agent is such that the predetermined distance is less than approximately 0.2 mm.

14. 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 in a housing, 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 to said housing, 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, by an adhesive agent, a light diffusing sheet that equalizes a distribution of two or more colors by being attached in such manner as to provide a predetermined separation air gap between the light diffusing sheet and one of a light emitting face of the light emitting diode assembly and a light receiving face of the focusing lens, wherein the adhesive agent is applied to a periphery of the light diffusing sheet to provide the separation air gap and a thickness of the adhesive agent is such that the separation air gap is less than approximately 0.2 mm.

15. The method of claim 14, wherein the light diffusing sheet comprises a sheet of material having an irregular surface thereon, the method further comprising:

adhering, with the adhesive agent 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.

16. The method of claim 15, wherein the predetermined separation gap is in a range of approximately 0.01 mm to approximately 0.2 mm.

17. The method of claim 14,

wherein the sheet of material has the irregular surface on each of two opposing sides of said sheet.