Light emitting apparatus

• US 20060043879A1
• Filed: 08/30/2005
• Published: 03/02/2006
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Naitou, Takahiro
• Granted Patent: US 7,569,987 B2
• Time in Patent Office: Days
• US Class Current: 313/501
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7728 containing europium
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• 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 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source

Abstract

An object of the present invention is to provide a light emitting apparatus that allows it to easily control the driving of LED and has high color rendering properties.

The light emitting apparatus comprises the first light emitting device 108a that has first peak emission wavelength in blue region and emits blue light, the fluorescent material 140 that is excited by the light from the first light emitting device 108a and emits red light, the second light emitting device 108b that has second peak emission wavelength which is longer than the first peak emission wavelength and is shorter than peak emission wavelength of the fluorescent material 140, and the second light emitting device 108b that emits green light of second peak emission wavelength which is longer than the first peak emission wavelength, so as to emit light generated by blending of blue light, green light and red light to the outside.

Claims

1. A light emitting apparatus comprising;

a first light emitting device that has a first peak emission wavelength in a short wavelength region of visible light,

a fluorescent material that converts light emitted by the first light emitting device to light of a different wavelength and,

a second light emitting device that has a second peak emission wavelength which is longer than the first peak emission wavelength and is shorter than the peak emission wavelength of the fluorescent material,

wherein the light emitted by the first light emitting device, the light emitted by the fluorescent material and the light emitted by the second light emitting device are mixed and emitted to the outside.

2. The light emitting apparatus according to claim 1,

wherein the fluorescent material is a nitride fluorescent material that contains at least one kind of group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba and Zn, at least one kind of group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and element N, and is activated with at least one kind of rare earth element selected from among the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu.

3. The light emitting apparatus according to claim 1,

wherein the fluorescent material produces such an emission spectrum, when excited by the light from the first light emitting device, as the light intensity consists of 100 parts attributable to the light of the first peak emission wavelength emitted by the first light emitting device and 80 parts attributable to the light of the second peak emission wavelength emitted by the second light emitting device.

4. A light emitting apparatus comprising;

a first light emitting device that has a first peak emission wavelength in ultraviolet region,

a fluorescent material that converts light emitted by the first light emitting device to light of a different wavelength and,

a second light emitting device that has a second peak emission wavelength longer than the first peak emission wavelength,

wherein the light emitted by the fluorescent material and the light emitted by the second light emitting device are mixed and emitted to the outside.

5. The light emitting apparatus according to claim 4,

wherein the fluorescent material is a nitride fluorescent material that contains at least one kind of group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba and Zn, at least one kind of group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and element N, and is activated with at least one kind of rare earth element selected from among the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu.

6. The light emitting apparatus according to claim 4,

wherein the fluorescent material produces such an emission spectrum, when excited by the light from the first light emitting device, as the light intensity consists of 100 parts attributable to the light of the first peak emission wavelength emitted by the first light emitting device and 80 parts attributable to the light of the second peak emission wavelength emitted by the second light emitting device.

7. A light emitting apparatus comprising;

a first light emitting device that has a first peak emission wavelength,

a fluorescent material that converts the light emitted by the first light emitting device to light of a different wavelength and;

a second light emitting device that has a second peak emission wavelength longer than the first peak emission wavelength,

wherein the first light emitting device and the second light emitting device are nitride compound semiconductors that emit light of different colors, and at least two of the light emitted by the first light emitting device, the light emitted by the fluorescent material and the light emitted by the second light emitting device are mixed and emitted to the outside.

8. The light emitting apparatus according to claim 7,

wherein the fluorescent material is a nitride fluorescent material that contains at least one kind of group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba and Zn, at least one kind of group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and element N, and is activated with at least one kind of rare earth element selected from among the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu.

9. The light emitting apparatus according to claim 7,

wherein the fluorescent material produces such an emission spectrum, when excited by the light from the first light emitting device, as the light intensity consists of 100 parts attributable to the light of the first peak emission wavelength emitted by the first light emitting device and 80 parts attributable to the light of the second peak emission wavelength emitted by the second light emitting device.