Light emitting device

• US 20050117334A1
• Filed: 06/04/2004
• Published: 06/02/2005
• Est. Priority Date: 11/27/2003
• Status: Active Grant

• Current Assignee: Jung-Pin Cheng, Kun-Chui Lee, Tzu-Chi Cheng
• Original Assignee: Jung-Pin Cheng, Kun-Chui Lee, Tzu-Chi Cheng
• Inventors: Cheng, Tzu-Chi, Cheng, Jung-Pin, Lee, Kun-Chui
• Granted Patent: US 7,207,691 B2
• Time in Patent Office: Days
• US Class Current: 362/231
• 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 33/50 Wavelength conversion elements
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light emitting device includes at least three light emitting source and a phosphor, with the three light sources consisted of following light emitting diodes (LED) emitting lights having different wavelengths. Wherein, two light sources are used to excite the phosphor to produce a distinct wavelength different from those of the two light sources. The distinct wavelength is blended with portions of the two light sources and a light source from another independent light source, and a blended light is released to obtain a white light having an excellent color rendering index.

Claims

1. A light emitting device comprising at least three light emitting sources and a phosphor, with the three light sources consisted by following light emitting diodes (LED) emitting lights having different wavelength;

wherein;

a first light source is formed by at least one first LED capable of emitting a blue light having a wavelength ranging between 360 nm and 480 nm;

a second light source is formed by at least one second LED capable of emitted a blue to green light having a wavelength ranging between 480 nm and 570 nm;

a third light source is formed by at least one third LED capable of emitting a red light having a wavelength ranging between 585 nm and 780 nm;

and the phosphor is for absorbing lights having different wavelengths and emitted by the first and second light sources, and is excited to emit a light having a wavelength distinct from those of the first and second light sources;

wherein, the distinct light is blended with the red light emitted from the third light source and the lights emitted from the first and second light sources, and a blended light is released to obtain a white light having an excellent color rendering index.

2. The light emitting device in accordance with claim 1, wherein the phosphor receives lights of different wavelengths from the first and second light sources, and is excited to emit a distinct light, which has a wavelength different from those of the first and second light sources and ranging between 500 nm and 585 nm.

3. The light emitting device in accordance with claim 1, wherein the phosphor is selected from at least one of following materials:

(a) YAG;

(b) S_im O⁴⁻

_n; and

(c) BxOy³.

4. The light emitting device in accordance with claim 1, wherein the phosphor is selected from one or several of following compounds:

(a) YAG;

Ce³⁺ having Ce as an activator for activating the phosphor;

(b) YAG;

Eu^2+/3+ having Eu as an activator for activating the phosphor; and

(c) YAG;

Tb³⁺ having Tb as an activator for activating the phosphor.

5. The light emitting device in accordance with claim 1, wherein the device is a printed circuit board (PCB), to which conducting pins of the first, second and third light sources are soldered to form an electric loop.