Light emitting device

• US 8,820,960 B2
• Filed: 02/15/2012
• Issued: 09/02/2014
• Est. Priority Date: 02/18/2011
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Yamamoto, Yuya
• Primary Examiner(s): Such, Matthew W
• Assistant Examiner(s): SPALLA, DAVID C
• Application Number:
  US13/396,855
• Publication Number:
  US 20120211779A1
• Time in Patent Office: 930 Days
• Field of Search: 257/89, 257/88, 257/E27.12, 362/231, 362/235
• US Class Current: 362/231
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21V 23/005 the substrate is supporting also the light source
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H05B 45/20 Controlling the colour of the light

Abstract

A light emitting device includes a white light emitting unit including a first light source emitting a white light; a red light emitting unit including a second light source emitting a white light and a red coating member having a red fluorescent material which converts the white light from the second light source into a red light; and a green light emitting unit including a third light source emitting a white light and a green coating member having a green fluorescent material which converts the white light from the third light source into a green light. The light emitting device further includes a driver for individually driving the white, the red and the green light emitting unit.

Claims

1. A light emitting device comprising:

a white light emitting unit including a first light source emitting a white light;

a red light emitting unit including a second light source emitting a white light and a red coating member having a red fluorescent material which converts the white light from the second light source into a red light;

a green light emitting unit including a third light source emitting a white light and a green coating member having a green fluorescent material which converts the white light from the third light source into a green light; and

a driver configured to individually drive the white, the red and the green light emitting unit

wherein each, of the first, the second and the third light source includes an LED chip emitting a first light and a fluorescent substance which converts the first light into a second light, and

wherein each of the first, the second and the third light source emits the white light by mixing a part of the first light not-converted by the fluorescent substance and the second light produced by the fluorescent substance.

2. The light emitting device of claim 1, wherein the white light emitting unit includes an adjustment coating member configured to adjust a chromaticity range of the white light from the first light source.

3. The light emitting device of claim 1, wherein the first light is a blue light and the second fight is a yellow light.

4. The light emitting device of claim 1, wherein the light emitting device is embedded in a lighting apparatus and is configured to emit a white light produced by mixing the red light, the green light and the white light emitted from the white light emitting unit.

5. The light emitting device of claim 2, wherein the first light is a blue light and the second light is a yellow light.

6. The light emitting device of claim 2, wherein the light emitting device is embedded in a lighting apparatus and is configured to emit a white light produced by mixing the red light, the green light and the white light emitted from the white light emitting unit.

7. The light emitting device of claim 3, wherein the light emitting device is embedded in a lighting apparatus and is configured to emit a white light produced by mixing the red light, the green light and the white light emitted from the white light emitting unit.

8. The light emitting device of claim 5, wherein the light emitting device is embedded in a lighting apparatus and is configured to emit a white light produced by mixing the red light, the green light and the white light emitted from the white light emitting unit.

9. The light emitting device of claim 1, a chromaticity variation of each of the red light and the green light is smaller than that of the white light.

10. The light emitting device of claim 2, a chromaticity variation of each of the red light and the green light is smaller than that of the white light.

11. The light emitting device of claim 3, a chromaticity variation of each of red light and the green light is smaller than that of the white light.

12. The light emitting device of claim 4, a chromaticity variation of each of the red light and the green light is smaller than that of the white light.

13. The light emitting device of claim 1, the light emitting device consists of the white light emitting unit, the red light emitting unit and the green light emitting unit.

14. The light emitting device of claim 2, the light emitting device consists of the white light emitting unit, the red light emitting unit and the green light emitting unit.

15. The light emitting device of claim 3, the light emitting device consists of the white light emitting unit, the red light emitting unit and the green light emitting unit.

16. The light emitting device of claim 4, the light emitting device consists of the white light emitting unit, the red light emitting unit and the green light emitting unit.

17. The light emitting device of claim 9, the light emitting device consists of the white light emitting unit, the red light emitting unit and the green light emitting unit.