LIGHT EMITTING DEVICE INCLUDING RGB LIGHT EMITTING DIODES AND PHOSPHOR

• US 20070284563A1
• Filed: 05/03/2005
• Published: 12/13/2007
• Est. Priority Date: 05/13/2004
• Status: Active Grant

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Seoul Semiconductor Co., Ltd.
• Inventors: Lee, Chung-Hoon, Roth, Gundula, Tews, Walter
• Granted Patent: US 9,209,162 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: H01L 2224/32013 the layer connector being larger than the bonding area, e.g. bond pad
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2924/00 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 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

Disclosed herein is a light emitting device including at least three light emitting diodes having different peak emission wavelengths to primarily emit light in a blue, green or red wavelength range, and a wavelength-conversion means to convert primary light into secondary light in a visible light wavelength range, The light emitting device of the current invention has a high color temperature of 2,000 to 8,000 K or 10,000 K and a high color rendering index of 90 or more, and emits yellow-green light or orange light having a wide emission wavelength range. Since the light emitting device having high color temperature and excellent color rendering properties can easily realize desired emission on the color coordinate system, it 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:

at least three light emitting diodes having different peak emission wavelengths to primarily emit light in a blue, green or red wavelength range; 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 said at least three light emitting diodes comprise:

a first light emitting diode having a peak emission wavelength between 440 and 500 nm;

a second light emitting diode having a peak emission wavelength between 500 and 570 nm; and

a third light emitting diode having a peak emission wavelength between 570 and 670 nm.

3. The device according to claim 1 or 2, further comprising at least one additional light emitting diode to emit light in a blue and/or blue-green wavelength range.

4. The device according to claim 3, wherein said at least one additional light emitting diode has a peak emission wavelength between 410 and 460 nm.

5. The device according to claim 1 or 2, wherein the light emitting diodes and the wavelength-conversion means are mounted in a single package.

6. The device according to claim 1 or 2, wherein the wavelength-conversion means comprises a single phosphor or a mixture of phosphors.

7. The device according to claim 1 or 2, wherein the wavelength-conversion means is placed on at least one of an upper surface, a lower surface, and a side surface of the light emitting diode, or is mixed with a conductive adhesive or distributed in a molded part.

8. The device according to claim 1 or 2, wherein the wavelength-conversion means comprises any one selected from among a first phosphor having a peak emission wavelength between 450 and 520 nm, a second phosphor having a peak emission wavelength between 500 and 570 nm, a third phosphor having a peak emission wavelength between 570 and 680 nm, and mixtures thereof.

9. The device according to claim 8, wherein each phosphor comprises one or more phosphor components in the corresponding wavelength range.

10. The device according to claim 5, 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.

11. The device according to claim 5, 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.

12. The device according to claim 10, wherein the substrate is formed of metal to emit heat generated by the one or more light emitting diodes.

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

14. The device according to claim 10, further comprising a molded part to enclose the light emitting diodes and the wavelength-conversion means on the substrate.

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

16. The device according to claim 5, 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.

17. The device according to claim 5, 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 one or more light emitting diodes.

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

19. The device according to claim 1 or 2, wherein the light emitting diodes each include a substrate formed of silicon carbide or sapphire and a nitride epitaxial layer formed on the substrate.