White light emitting diode with first and second LED elements

• US 7,365,485 B2
• Filed: 10/15/2004
• Issued: 04/29/2008
• Est. Priority Date: 10/17/2003
• Status: Expired due to Fees

• Current Assignee: Citizen Electronics Company Limited
• Original Assignee: Citizen Electronics Company Limited
• Inventors: Oishi, Nodoka, Fukasawa, Koichi
• Primary Examiner(s): Patel; Nimeshkumar D.
• Assistant Examiner(s): QUARTERMAN, KEVIN J
• Application Number:
  US10/965,177
• Publication Number:
  US 20050082974A1
• Time in Patent Office: 1,292 Days
• Field of Search: 313498-504, 313/506, 313/512, 362/84, 362/231, 257/E33.069, 257/E25.032, 257/E25.02, 257/E25.023
• US Class Current: 313/502
• 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 light emitting diode for emitting illumination light comprising:

a first light emitting diode element and a second light emitting diode element which have mutually different emission wavelengths; and

a sealing member including a fluorescent material which is excited to emit yellow light and sealing the first light emitting diode element and the second light emitting diode element,

the first light emitting diode element being a blue light emitting diode element having a peak wavelength of 470 nm to 490 nm,

the second light emitting diode element being a red light emitting diode element for emitting red light, and

a part above the red light emitting diode element being covered with a light shielding coat.

2. The white light emitting diode according to claim 1, wherein each of the first and second light emitting diode elements is electrically connected to independent terminals, respectively, and energization of the first and second light emitting diode elements is separately controlled.

3. The white light emitting diode according to claim 2, wherein the first light emitting diode element comprises a plurality of blue light emitting diode elements and the second light emitting diode element comprises one red light emitting diode element.

4. The white light emitting diode according to claim 3, wherein each of the plurality of blue light emitting diode elements is electrically connected to corresponding terminals respectively and energization thereof is separately controlled.

5. The white light emitting diode according to claim 1, wherein the first and second light emitting diode elements are mounted on a common board provided with conductive means corresponding to the first and second light emitting diode elements, respectively, and are sealed by the sealing member.

6. The white light emitting diode according to claim 5, wherein a reflecting member having a reflecting surface which is formed into a penetrating concave portion is attached to surround a periphery of the sealing member on the common board on which the first and second light emitting diode elements are mounted.

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

8. The white light emitting diode according to claim 1, wherein the blue light emitting diode element is of a GaN type.

9. The white light emitting diode according to claim 1, wherein the red light emitting diode element comprises GaAlAs or GaAlInP.

10. The white light emitting diode according to claim 1, wherein the fluorescent material is YAG.

11. The white light emitting diode according to claim 2, wherein at least one of the corresponding terminals comprises a through-hole electrode.

12. The white light emitting diode according to claim 1, wherein at least the red light emitting diode element is sealed by a half-transparent resin.

13. The light emitting diode according to claim 1, wherein the blue light emitting diode has a peak wavelength greater than 470 nm.

14. The light emitting diode according to claim 1, wherein the blue light emitting diode has a peak wavelength of 480 nm to 490 nm.

15. The light emitting diode according to claim 1, wherein the blue light emitting diode has a peak wavelength of 480 nm.