High efficient phosphor-converted light emitting diode

• US 20080006815A1
• Filed: 07/03/2007
• Published: 01/10/2008
• Est. Priority Date: 07/04/2006
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Lu, Chih-Chiang, Hsieh, Min-Hsun, Wang, Chien-Yuan
• Granted Patent: US 7,732,827 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

A light-emitting device and manufacturing method thereof are disclosed. The light-emitting device includes a substrate, a semiconductor light-emitting structure, a filter layer, and a fluorescent conversion layer. The method comprises forming a semiconductor light-emitting structure over a substrate, forming a filter layer over the semiconductor light-emitting structure, and forming a fluorescent conversion layer over the filter layer.

Claims

1. A light-emitting device, comprising:

a semiconductor structure with an active layer emitting a first wavelength light;

a conversion layer on said semiconductor structure, said conversion layer absorbs said first wavelength light and converted at least a portion of said first wavelength light into a second wavelength light ; and

a first filter layer in-between said semiconductor structure and said conversion layer.

2. The light-emitting device according to claim 1, wherein said first filter layer is composed of materials having a reflectivity selection or a transmissivity selection to light of different wavelengths.

3. The light-emitting device according to claim 2, wherein said first filter layer is formed by a kind of material, or stacking or mixing two or more kind of materials.

4. The light-emitting device according to claim 1, wherein said conversion layer is formed by at least one organic or inorganic luminescence material.

5. The light-emitting device according to claim 1, wherein said first filter layer having a light transmissivity of more than 50% to the first wavelength light and a light reflectivity of more than 50% to the second wavelength light.

6. The light-emitting device according to claim 1, wherein said first filter layer is stacked by at least two materials with different refractive indexes, and a thickness of said first filter layer is in a range of several tens of angstroms to several tens of micrometers.

7. The light-emitting device according to claim 6, wherein said first filter layer has a higher refractive material with a refractive index of 2.1 to 2.6 and a lower refractive material with a refractive index of 1.2 to 1.6.

8. The light-emitting device according to claim 7, wherein said higher refractive index material is selected form a group of TiO₂, Nb₂O₅ and Ta₂O₅.

9. The light-emitting device according to claim 7, wherein said lower refractive index material is selected from a group of SiO₂ and MgF₂.

10. The light-emitting device according to claim 1, further including a second filter layer on said conversion layer.

11. The light-emitting device according to claim 1, wherein said conversion layer including a fluorescent material.

12. A light-emitting device, comprising:

a semiconductor structure having an active layer to emit a first wavelength light;

a conversion layer on said semiconductor structure, said conversion layer absorbs said first wavelength light and converted at least a portion of said first wavelength light into a second wavelength light;

a first filter layer, in between said semiconductor structure and said conversion layer; and

a second filter layer on said conversion layer.

13. The light-emitting device according to claim 12, wherein said first filter layer having a light transmissivity of more than 50% to said first wavelength light and a light reflectivity of more than 50% to said second wavelength light.

14. The light-emitting device according to claim 12, wherein said second filter layer having a light reflectivity of more than 50% to said first wavelength light and a light transmissivity of more than 50% to said second wavelength light.

15. The light-emitting device according to claim 12, wherein said first filter layer and said second filter layer are stacked by at least two materials with different refractive indexes.

16. The light-emitting device according to claim 15, wherein each of said first filter layer and said second filter layer having a thickness in a range of several tens of angstroms to several tens of micrometers.

17. The light-emitting device according to claim 15, wherein each of said first filter layer and said second filter layer having a higher refractive material with a refractive index of 2.1 to 2.6 and a lower refractive material with a refractive index of 1.2 to 1.6.

18. The light-emitting device according to claim 17, wherein said higher refractive index material a is selected form a group of TiO₂, Nb₂O₅ and Ta₂O₅.

19. The light-emitting device according to claim 17, wherein said lower refractive index material is selected form a group of SiO₂ and MgF₂.

20. The light-emitting device according to claim 12, wherein said conversion layer including a fluorescent material.