Method and apparatus for generating phosphor film with textured surface

• US 7,825,427 B2
• Filed: 09/12/2008
• Issued: 11/02/2010
• Est. Priority Date: 09/12/2008
• Status: Active Grant

• Current Assignee: Bridgelux Incorporated
• Original Assignee: Bridgelux Incorporated
• Inventors: Shaikevitch, Alex, Xu, Tao
• Primary Examiner(s): Patel; Nimeshkumar D
• Assistant Examiner(s): Bowman; Mary Ellen
• Application Number:
  US12/209,638
• Publication Number:
  US 20100066236A1
• Time in Patent Office: 781 Days
• Field of Search: 313500-512, 257 98-100
• US Class Current: 257/100
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body

Abstract

An optical device deploring a phosphor layer having a textured surface to improve output of visual light is disclosed. A light emitting device includes a solid state light emitter and a phosphor layer. The solid state light emitter, for example, is configured to convert electrical energy to optical light. The phosphor layer includes a first surface and a second surface, wherein the first surface, for example, is the top surface while the second surface is the bottom surface. The phosphor layer is disposed over the solid state light emitter for generating luminous light in response to the optical light. The first surface of the phosphor layer, in one embodiment, is configured to include a texture, which has similarly shaped uniform configurations, capable of reducing total internal reflection.

Claims

1. A light emitting device, comprising:

a solid state light emitter capable of converting electrical energy to optical light;

a phosphor layer, having a first surface and a second surface, disposed over the solid state light emitter for generating luminous light in response to the optical light, wherein the first surface of the phosphor layer is configured to include a texture having similarly shaped continuous configurations capable of reducing total internal reflection (“

TIR”

) between the solid state light emitter and the phosphor layer; and

a plurality of phosphor islands disposed over the phosphor layer for generating warmer light, wherein each of the plurality of phosphor islands includes a top surface and a bottom surface, wherein the top surface is configured to include a texture capable of reducing TIR between the phosphor layer and the plurality of phosphor islands.

2. The device of claim 1, further comprising a light extracting layer disposed between the phosphor layer and the solid state light emitter for extracting the optical light from the solid state light emitter.

3. The device of claim 2,

wherein the light extracting layer is a clear silicone layer;

and

wherein the solid state light emitter is a light emitter diode (“

LED”

).

4. The device of claim 3, wherein the light extracting layer is structured in a dome shape capable of extracting and scattering the optical light from the LED to the phosphor layer.

5. The device of claim 1, wherein the texture having similarly shaped continuous configurations is a surface with two-dimensional continuously uniformed distributed triangles.

6. The device of claim 1, wherein the texture having similarly shaped continuous configurations is a surface with two-dimensional continuously uniformed distributed hemispheres.

7. The device of claim 6, wherein each of the continuously distributed hemispheres has a diameter, which is in a range between 0.1 micrometer and 1 millimeter.

8. The device of claim 1, wherein the second surface, which faces a direction toward the solid state light emitter, includes a texture having similarly shaped uniform configurations capable of reducing TIR between the solid state light emitter and the phosphor layer.

9. The device of claim 1, wherein the first surface is configured to face a direction toward the solid state light emitter.

10. A method for manufacturing a lighting device, comprising:

placing a light emitter diode (“

LED”

) on a substrate;

dispensing a silicone layer over the LED for extracting optical light from the LED;

dispensing a phosphor layer over the silicone layer for generating luminous cool light;

generating a textured surface on a first surface of the phosphor layer for reducing total internal reflections (“

TIR”

) at the phosphor layer; and

depositing a plurality of phosphor islands having a textured surface over the phosphor layer to generate warmer light and reduce TIR.

11. The method of claim 10, wherein generating a textured surface further includes etching a texture having similarly shaped uniform configurations capable of reducing TIR.

12. The method of claim 11, wherein etching a texture having a similarly shaped uniform configurations capable of reducing TIR includes providing a surface with continuously distributed hemispheres.

13. The method of claim 12, wherein providing a surface with continuously distributed hemispheres further includes setting a range of hemispherical diameter between 0.1 micrometer and 1 millimeter.

14. The method of claim 11, wherein creating a texture having a similarly shaped uniform configurations capable of reducing TIR includes providing a surface with continuously distributed triangles.

15. The method of claim 14, wherein providing a surface with continuously distributed triangles further includes setting a range of line segment between 0.1 micrometer and 1 millimeter.

16. The method of claim 10, further comprising generating a textured surface on a second surface of the phosphor layer for minimizing TIR at the phosphor layer.

17. An apparatus for manufacturing a lighting device, comprising:

means for placing a light emitter diode (“

LED”

) on a substrate;

means for dispensing a silicone layer over the LED for extracting optical light from the LED;

means for dispensing a phosphor layer over the silicone layer for generating luminous cool light;

means for generating a textured surface on a first surface of the phosphor layer for reducing total internal reflections (“

TIR”

) at the phosphor layer; and

means for depositing a plurality of phosphor islands having a textured surface over the phosphor layer to generate warmer light and reduce TIR.

18. The apparatus of claim 17, wherein means for generating a textured surface further includes means for etching a texture having similarly shaped uniform configurations capable of reducing TIR.

19. The apparatus of claim 18, wherein means for etching a texture having a similarly shaped uniform configuration capable of reducing TIR includes means for providing a surface with continuously distributed hemispheres.

20. The apparatus of claim 19, wherein means for providing a surface with continuously distributed hemispheres further includes means for setting a range of hemispherical diameter between 0.1 micrometer and 1 millimeter.