White light emitting diode

• US 20050082974A1
• Filed: 10/15/2004
• Published: 04/21/2005
• Est. Priority Date: 10/17/2003
• Status: Active Grant

• Current Assignee: Citizen Electronics Company Limited
• Original Assignee: Citizen Electronics Company Limited
• Inventors: Fukasawa, Koichi, Oishi, Nodoka
• Granted Patent: US 7,365,485 B2
• Time in Patent Office: Days
• US Class Current: 313/512
• CPC Class Codes: G03B 27/72 Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

A white LED (20) for emitting illumination light entirely to exterior, comprising a first LED element (4) and a second LED element (5) which have mutually different emission wavelengths, and a sealing member (10) including a fluorescent material (8) which is excited to emit yellow light (sy) and for sealing at least the first LED element, the first LED element (4) being a long wave length-blue LED element for emitting blue light (sb 1) of a long wave length in which a peak wave length is in the range of 470 nm to 490 nm, the second LED element being a red LED element for emitting red light (sr).

Claims

1. A white LED for emitting illumination light comprising:

a first LED element and a second LED element which have mutually different emission wavelengths; and

a sealing member including a fluorescent material which is excited to emit yellow light and sealing at least the first LED element,

the first LED element being at least one long wavelength-blue LED element for emitting blue light of a long wavelength,

the second LED element being a red LED element for emitting red light.

2. The white LED according to claim 1, wherein a peak wavelength of at least one blue LED which is the first LED element has a range of 470 nm to 490 nm.

3. The white LED according to claim 1, wherein each of the first and second LED elements is electrically connected with corresponding terminals, respectively, and energization of the first and second LED elements are separately controlled in energization.

4. The white LED according to claim 3, wherein the first LED element comprises a plurality of blue LED elements which have a long wavelength respectively and the second LED element comprises one red LED element.

5. The white LED according to claim 4, wherein each of the plurality of blue LED elements is electrically connected with corresponding terminals respectively and energization thereof is separately controlled.

6. The white LED according to claim 1, wherein the first and second LED elements are mounted on a common board provided with conductive means corresponding to the first and second LED elements, respectively, and are sealed by a sealing member including a florescent material which is excited to emit yellow light.

7. The white LED according to claim 6, wherein a reflecting member having a reflecting surface which is formed into a concave portion is attached in a periphery of the sealing member on the common board on which the first and second LED elements are mounted.

8. The white LED according to claim 1, wherein a peak wave length of the red LED element which is the second LED element has a range of 620 nm to 660 nm.

9. The white LED according to claim 1, wherein the long wavelength-blue LED element is a GaN system.

10. The white LED according to claim 1, wherein the red LED element comprises GaAlAs or GaAlInP.

11. The white LED according to claim 1, wherein the florescent material is YAG.

12. The white LED according to claim 3, wherein at least one of the corresponding terminals is a through-hole electrode conducting with a through hole.

13. The white LED according to claim 1, wherein a part of above the red LED element is covered with a light shielding coat.

14. The white LED according to claim 1, wherein at least the red LED element is sealed by a half-transparent resin.