LIGHT EMITTING DEVICE

• US 20090262515A1
• Filed: 05/03/2005
• Published: 10/22/2009
• Est. Priority Date: 05/06/2004
• Status: Active Grant

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Seoul Optodevice Company Limited (Seoul Semiconductor Co., Ltd.)
• Inventors: Lee, Chung-Hoon, Roth, Gundula, Tews, Walter
• Granted Patent: US 8,071,988 B2
• Time in Patent Office: Days
• US Class Current: 362/84
• CPC Class Codes: H01L 2224/32013 the layer connector being larger than the bonding area, e.g. bond pad
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

Disclosed herein is a light emitting device including one or more light emitting diodes to primarily emit light having different wavelengths in the wavelength range of ultraviolet rays and/or blue light, and a wavelength-conversion means to convert the primary light into secondary light in the visible light wavelength range. The light emitting device of the current invention has a high color temperature of 2000 to 8000 K or 10000 K and a high color rendering index of 90 or more, thus easily realizing desired emission on the color coordinate system. Therefore, the lighting emitting device is applicable to mobile phones, notebook computers, and keypads or backlight units for various electronic products, and, in particular, automobiles and exterior and interior lighting fixtures.

Claims

1. A light emitting device, comprising:

one or more light emitting diodes to primarily emit light having different wavelengths in a wavelength range of ultraviolet rays and/or blue light; and

a wavelength-conversion means to convert the primary light into secondary light in a visible light wavelength range.

2. The device according to claim 1, wherein the one or more light emitting diodes include:

a first light emitting diode having a peak emission wavelength between 360 and 420 nm;

3. The device according to claim 1, wherein the one or more light emitting diodes include:

a first light emitting diode having a peak emission wavelength between 390 and 450 nm; and

a second light emitting diode having a peak emission wavelength between 440 and 500 nm.

4. The device according to any one of claims 1, wherein the light emitting diodes to emit primary light and the wavelength-conversion means are mounted in a single package.

5. The device according to any one of claims 1, wherein the wavelength-conversion means comprises one or more phosphors having different properties.

6. The device according to any one of claims 1, wherein the wavelength-conversion means is placed on at least one of a side surface, an upper surface, and a lower surface of the light emitting diode, or is used in a mixture with an adhesive or a molding material.

7. The device according to any one of claims 1, wherein the wavelength-conversion means includes any one selected from among

a first phosphor having a peak emission wavelength between 440 and 500 nm,

a second phosphor having a peak emission wavelength between 500 and 590 nm,

a third phosphor having a peak emission wavelength between 580 and 700 nm, and mixtures thereof.

8. The device according to claim 7, wherein each phosphor includes one or more phosphor components having different properties in the corresponding wavelength range.

9. The device according to claim 4, wherein the single package is formed into a chip package, which comprises a substrate, one or more light emitting diodes mounted on the substrate, and a wavelength-conversion means placed around the light emitting diodes.

10. The device according to claim 4, wherein the single package is formed into a top package, which comprises a substrate having a reflector formed thereon, one or more light emitting diodes mounted on the substrate, and a wavelength-conversion means placed around the light emitting diodes.

11. The device according to claim 9, wherein the substrate is formed of metal to emit heat generated by the one or more light emitting diodes.

12. The device according to claim 11, further comprising a radiation sheet mounted on the substrate formed of metal.

13. The device according to claim 9, further comprising a molded part to enclose the light emitting diodes and the wavelength-conversion means on the substrate.

14. The device according to claim 13, wherein the wavelength-conversion means is uniformly distributed in the molded part.

15. The device according to claim 4, wherein the single package is formed into a lamp package, which comprises a pair of lead electrodes, one or more light emitting diodes mounted on one of the pair of lead electrodes, a wavelength-conversion means placed around the light emitting diodes, and a molded part to enclose the light emitting diodes and the wavelength-conversion means.

16. The device according to claim 4, wherein the single package is formed into a high output package, which comprises one or more light emitting diodes, a wavelength-conversion means placed around the light emitting diodes, and a heat sink to emit heat generated by the light emitting diodes.

17. The device according to claim 16, further comprising a radiation sheet to emit heat from the heat sink.

18. The device according to any one of claims 1, wherein the light emitting diodes each include a substrate formed of silicon carbide or sapphire and a nitride epitaxial layer formed on the substrate.