High efficient phosphor-converted light emitting diode

• US 7,732,827 B2
• Filed: 07/03/2007
• Issued: 06/08/2010
• Est. Priority Date: 07/04/2006
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Hsieh, Min-Hsun, Lu, Chih-Chiang, Wang, Chien-Yuan
• Primary Examiner(s): Lee; Calvin
• Application Number:
  US11/822,181
• Publication Number:
  US 20080006815A1
• Time in Patent Office: 1,071 Days
• Field of Search: 257 10- 13, 257 79-106, 257E51018-E51022, 257E33001-E33077, 438 22- 35
• US Class Current: 257/98
• 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 converts 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, 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.

2. A light-emitting diode, 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 converts 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 wherein said light-emitting diode emits white light, and;

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.

3. The light-emitting diode according to claim 2, 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.

4. The light-emitting diode according to claim 2, wherein said first filter layer and said second filter layer are stacked by at least two materials with different refractive indexes.

5. The light-emitting diode according to claim 4, 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.

6. The light-emitting diode according to claim 4, 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.

7. The light-emitting diode according to claim 6, wherein said higher refractive index material a is selected form a group of TiO₂, Nb₂O₅ and Ta₂O₅.

8. The light-emitting diode according to claim 6, wherein said lower refractive index material is selected form a group of SiO₂ and MgF₂.

9. The light-emitting diode according to claim 2, wherein said conversion layer includes a fluorescent material.

10. A light-emitting diode, comprising:

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

a conversion layer on said semiconductor structure; and

a first filter layer in-between said semiconductor structure and said conversion layer, wherein said first wavelength light passes through said filter layer and enters said conversion layer and is partially absorbed and converted into a second wavelength light and unabsorbed first wavelength light is mixed with said second wavelength light and white light is generated.

11. The light-emitting diode according to claim 10, wherein said first filter layer is composed of materials having a reflectivity selection or a transmissivity selection to light of different wavelengths.

12. The light-emitting diode according to claim 11, wherein said first filter layer is formed by a kind of material, or stacking or mixing two or more kind of materials.

13. The light-emitting diode according to claim 10, wherein said conversion layer is formed by at least one organic or inorganic luminescence material.

14. The light-emitting diode according to claim 10, 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.

15. The light-emitting diode according to claim 10, 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.

16. The light-emitting diode according to claim 15, 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.

17. The light-emitting diode according to claim 16, wherein said higher refractive index material is selected form a group of TiO₂, Nb₂O₅ and Ta₂O₅.

18. The light-emitting diode according to claim 16, wherein said lower refractive index material is selected from a group of SiO₂ and MgF₂.

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

20. The light-emitting diode according to claim 10, wherein said conversion layer includes a fluorescent material.