Light emititng device

• US 20040061115A1
• Filed: 07/09/2003
• Published: 04/01/2004
• Est. Priority Date: 01/10/2001
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Shibata, Naoki, Kozawa, Takahiro
• Granted Patent: US 6,891,203 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/01025 Manganese [Mn]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

According to the invention, a Group III nitride compound semiconductor light-emitting element is provided with a light-emitting layer comprising two layers of different in ratio of AlGaInN composition, and emitting light with an emission peak wavelength in an ultraviolet region and light with an emission peak wavelength in a visible region. The light-emitting element and a fluorescent material excited by light in the ultraviolet region are combined to configure a light emitting device.

Claims

1. A light emitting device comprising:

a light-emitting element comprising a Group III nitride compound semiconductor and having a light-emitting layer emitting light with an emission peak wavelength in an ultraviolet region and light with an emission peak wavelength in a visible region; and

a fluorescent material excited by said light in the ultraviolet region to emit light with a wavelength different from that of excitation light.

2. A light-emitting device according to claim 1, wherein the emission peak wavelength of the light in the visible region is in a range of from 430 to 560 nm.

3. A light emitting device according to claim 2, wherein the emission peak wavelength of the light in the visible region is in a range of from 450 to 490 nm.

4. A light emitting device according to claim 1, wherein the light-emitting layer has a region of Al_x1Ga_1-x1-x2In_x2N (0<

x1<

1, 0<

x2<

1, x1>

x2) emitting the light in the ultraviolet region and a region of Al_y1Ga_1-y1-y2In_y2N (0<

y1<

1, 0<

y2<

1, y1<

y2) emitting the light in the visible region.

5. A light emitting device according to claim 4, wherein the region of Al_x1Ga_1-x1-x2In_x2N (0<

x1<

1, 0<

x2<

1, x1>

x2) and the region of Al_y1Ga_1-y1-y2In_y2N (0<

y1<

1, 0<

y2<

1, y1<

y2) are formed within a single layer.

6. A light emitting device according to claim 1, wherein the light-emitting layer has a region of Al_xGa_1-xN (0≦

x≦

1) emitting the light in the ultraviolet region and a region of In_yGa_1-yN (0≦

y≦

1) emitting the light in the visible region.

7. A light emitting device according to claim 6, wherein the region of Al_xGa_1-xN (0≦

x≦

1) and the region of In_yGa_1-yN (0≦

y≦

1) are formed within a single layer.

8. A light emitting device according to claim 1, wherein the light from the light-emitting element and the light from the fluorescent material are mixed and emitted.

9. A light emitting device according to claim 1, wherein the light emitting direction is shielded by a light transmitting material dispersed with the fluorescent material.

10. A light emitting device according to claim 9, wherein the light-emitting element is mounted on a cup portion of a lead frame, while the cup portion is filled with the light transmitting material dispersed with the fluorescent material.

11. A light emitting device according to claim 1, wherein the emission peak wavelength of the light in the ultraviolet region is in a range of 360 nm or less.