Light emitting diode with a quasi-omnidirectional reflector

• US 20060145172A1
• Filed: 06/13/2005
• Published: 07/06/2006
• Est. Priority Date: 12/30/2004
• Status: Abandoned Application

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Chu, Cheng-Wei, Su, Jung-Chieh
• Application Number:
  US11/150,103
• Publication Number:
  US 20060145172A1
• Time in Patent Office: Days
• 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
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A light emitting diode with a quasi-omnidirectional reflector comprises a luminescent gel which is coated surrounding a UV light LED chip and a quasi-omnidirectional reflector which is disposed above the luminescent gel. The quasi-omnidirectional reflector is a wild angle cut-off filter which is made by a cooperation of a method for an optical film coating and a property of a total reflection. According to the property of the optical film coating, a light with an incident angle smaller than a critical angle can be reflected, such that a light form the LED chip is confined in the luminescent gel, which makes the luminescent material is excited as much as possible for improving the conversion efficiency of the light. When this LED chip co-works with different colors of the luminescent gels, different colors of lights are excited and produced.

Claims

1. A light emitting diode (LED) with a quasi-omnidirectional reflector, comprising:

a substrate, which has an ability for manufacturing a circuit;

at least one LED chips, which are disposed on the substrate and emits a light from a emitting surface of the LED chip;

a luminescent gel, which is composed of a mixture of a luminescent material and an epoxy, and is coated surrounding the LED chip, wherein when the light from the LED chip penetrates through the luminescent gel, exciting the luminescent material to produce a fluorescent light; and

a wild angle cut-off filter, which is made by a method of an optical film coating and is disposed at a side of the luminescent gel, which corresponds to the emitting surface of the LED chip, wherein when an incident angle for the light from the LED chip is larger than a specific angle range, the light will be totally reflected and confined in the luminescent gel to produce multiple and repeatable reflection due to the differences between the refractive index of the luminescent gel and that of an air for improving a conversion efficiency of a white light.

2. The light emitting diode (LED) of claim 1, wherein the LED chip is a UV light LED chip, which co-works with different colors of the luminescent gels to excite and produce different colors of the lights.

3. The light emitting diode (LED) of claim 1, wherein the LED chip is a blue light LED and the luminescent gel is a yellow light luminescent gel, producing the white light.

4. The light emitting diode (LED) of claim 1, wherein the LED chip is a blue light LED and the luminescent gel is a red light luminescent gel, producing a red light.

5. The light emitting diode (LED) of claim 1, wherein the LED chip is a blue light LED and the luminescent gel is a green light luminescent gel, producing a green light.

6. The light emitting diode (LED) of claim 1, wherein the specific angle is a critical angle of a UV light.

7. The light emitting diode (LED) of claim 1, wherein when the incident angle for the light emitting to the wild angle cut-off filter is smaller than the specific angle range, the light will be totally reflected according to a design of the optical film coating for the wild angle cut-off filter.

8. The light emitting diode (LED) of claim 1, wherein a visible light emitting spectrum of the luminescent material cooperates with a light emitting wavelength of the LED chip.

9. The light emitting diode (LED) of claim 1, wherein the substrate is a bowl type structure which has an ability to reflect the light.

10. The light emitting diode (LED) of claim 1, wherein the substrate is a plate type structure.

11. The light emitting diode (LED) of claim 1, further comprising a light reflection layer at one side of the substrate which mounts the LED chip to cooperate the wild angle cut-off filter to form a resonance structure producing multiple reflections for the light.

12. The light emitting diode (LED) of claim 1, wherein the light reflection layer is another wild angle cut-off filter.

13. The light emitting diode (LED) of claim 1, wherein the LED chip is a UV light LED chip.

14. The light emitting diode (LED) of claim 1, wherein the LED chips are arranged in matrix.

15. The light emitting diode (LED) of claim 1, wherein the emitting surface of the LED chip further comprises a short wave pass filter for increasing a light emitting amounts of the LED chip.

16. The light emitting diode (LED) of claim 1, wherein the wild angle cut-off filter reflects a light with a wavelength of the light from the LED chip.

17. The light emitting diode (LED) of claim 1, wherein the wild angle cut-off filter penetrates the fluorescent light.

18. The light emitting diode (LED) of claim 1, wherein the wild angle cut-off filter is made by using at least one high refractive index material and at least one low refractive index material to proceed the method of the optical film coating.

19. The light emitting diode (LED) of claim 18, wherein the high refractive index material is selected from one group consisted of a TiO₂, a Ta₂O₅, an Nb₂O₅, a CeO₂, and a ZnS.

20. The light emitting diode (LED) of claim 18, wherein the low refractive index material is selected from one group consisted of a SiO₂ and an MgF₂.

21. The light emitting diode (LED) of claim 1, wherein the wild angle cut-off filter is made by a method selected from one group consisted of a sputtering, an E-gun, and a chemical vapor deposition.

22. The light emitting diode (LED) of claim 1, further comprising a diffraction optical element which is disposed at another side of the wild angle cut-off filter which corresponds to the luminescent gel.

23. The light emitting diode (LED) of claim 1, further comprising a dome lens which is disposed at another side of the wild angle cut-off filter which corresponds to the luminescent gel.

24. The light emitting diode (LED) of claim 1, further comprising a micro lens which is disposed at another side of the wild angle cut-off filter which corresponds to the luminescent gel.

25. The light emitting diode (LED) of claim 1, further comprising a visible light pass filter which is disposed at another side of the wild angle cut-off filter which corresponds to the luminescent gel.

26. The light emitting diode (LED) of claim 1, further comprising an anti-reflection coating film which is disposed at another side of the wild angle cut-off filter which corresponds to the luminescent gel.

27. A light emitting diode (LED) with a quasi-omnidirectional reflector, where a LED chip is disposed in a metal bowl with a frame that has two independent metal electrodes for passing through a current to drive the LED chip for emitting a light, wherein a luminescent gel consisted of a luminescent material and an epoxy is coated surrounding the LED chip, when the light from the LED chip penetrating through the luminescent gel, the luminescent material is excited to emit a fluorescent light, wherein the light emitting diode with the quasi-omnidirectional reflector is characterized by:

a wild angle cut-off filter, which is made by a method of an optical film coating and is disposed at a surface of the luminescent gel, wherein when an incident angle for the light is larger than a specific angle range, the light will be totally reflected and confined in the luminescent gel to produce multiple and repeatable reflection due to the differences between the refractive index of the luminescent gel and that of an air for improving a conversion efficiency of a white light.

28. The light emitting diode (LED) of claim 27, wherein the LED chip is a UV light LED chip, which co-works with different colors of the luminescent gels to excite and produce different colors of the lights.

29. The light emitting diode (LED) of claim 27, wherein the specific angle is a critical angle of the UV light.

30. The light emitting diode (LED) of claim 27, wherein the LED chip is a blue light LED and the luminescent gel is a yellow light luminescent gel, producing the white light.

31. The light emitting diode (LED) of claim 27, wherein the LED chip is a blue light LED and the luminescent gel is a red light luminescent gel, producing a red light.

32. The light emitting diode (LED) of claim 27, wherein the LED chip is a blue light LED and the luminescent gel is a green light luminescent gel, producing a green light.

33. The light emitting diode (LED) of claim 27, wherein when the incident angle for the light emitting to the wild angle cut-off filter is smaller than the specific angle range, the light will be totally reflected according to a design of the optical film coating for the wild angle cut-off filter.

34. The light emitting diode (LED) of claim 27, wherein a visible light emitting spectrum of the luminescent material cooperates with a light emitting wavelength of the LED chip.

35. The light emitting diode (LED) of claim 27, wherein the wild angle cut-off filter is made by using at least one high refractive index material and at least one low refractive index material to proceed the method of the optical film coating.

36. The light emitting diode (LED) of claim 35, wherein the high refractive index material is selected from one group consisted of a TiO₂, a Ta₂O₅, an Nb₂O₅, a CeO₂, and a ZnS.

37. The light emitting diode (LED) of claim 35, wherein the low refractive index material is selected from one group consisted of a SiO₂ and an MgF₂.

38. The light emitting diode (LED) of claim 27, wherein the wild angle cut-off filter is made by a method selected from one group consisted of a sputtering, an E-gun, and a chemical vapor deposition.