LIGHT EMITTING DEVICE AND DISPLAY

• US 20090315015A1
• Filed: 08/27/2009
• Published: 12/24/2009
• Est. Priority Date: 07/29/1996
• Status: Active Grant

• Current Assignee: Kensho Sakano, Toshio Moriguchi, Yasunobu Noguchi, Yoshinori Shimizu
• Original Assignee: Kensho Sakano, Toshio Moriguchi, Yasunobu Noguchi, Yoshinori Shimizu
• Inventors: Moriguchi, Toshio, Sakano, Kensho, Noguchi, Yasunobu, SHIMIZU, Yoshinori
• Granted Patent: US 7,969,090 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: C09K 11/7767 Chalcogenides
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: H01J 29/20 characterised by the luminescent material
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/45169 Platinum (Pt) as principal constituent
• 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 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/45 of an individual wire connector
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01021 : Scandium [Sc]
• CPC Class Codes: H01L 2924/01067 : Holmium [Ho]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/12036 : PN diode
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/20751 : larger or equal to 10 microns less than 20 microns
• CPC Class Codes: H01L 2924/20752 : larger or equal to 20 microns less than 30 microns
• CPC Class Codes: H01L 2924/20753 : larger or equal to 30 microns less than 40 microns
• CPC Class Codes: H01L 2924/20754 : larger or equal to 40 microns less than 50 microns
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 2933/0091 : Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/50 : Wavelength conversion elements
• CPC Class Codes: H01L 33/501 : characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/504 : Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/56 : Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H05B 33/14 : characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: Y02B 20/00 : Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A light emitting device containing a semiconductor light emitting component and a phosphor, the phosphor is capable of absorbing a part of light emitted by the light emitting component and emitting light of a wavelength different from that of the absorbed light, is provided. A straight line connecting a point of chromaticity corresponding to a spectrum generated by the light emitting component and a point of chromaticity corresponding to a spectrum generated by the phosphor is substantially along a black body radiation locus in a chromaticity diagram.

Claims

1. A light emitting diode comprising:

a lead,

an LED chip mounted on said lead,

a transparent material covering said LED chip, and

a phosphor contained in said transparent material and absorbing a part of light emitted by the LED chip and emitting light of wavelength different from that of the absorbed light;

wherein a particle of said phosphor reflects said light from another particle of said phosphor, and

a concentration of said phosphor in the vicinity of said LED chip is larger than a concentration of said phosphor in the vicinity of the surface of said transparent material.

2. The light emitting diode according to claim 1, wherein light emitted by said phosphor is reflected by another particle of said phosphor and further reflected by the surface of said lead.

3. The light emitting diode according to claim 1, wherein the surface of said lead is mirror polished.

4. The light emitting diode according to claim 1, wherein said lead has a surface roughness of not less than 0.1 S and not more than 0.8 S.

5. The light emitting diode according to claim 1, the main emission peak of said LED chip is within the range from 400 nm to 530 nm.

6. The light emitting diode according to claim 1, wherein said LED chip emits a light having a spectrum with a peak in the range from 420 to 490 nm, said phosphor emits light having a spectrum with a peak in the range from 510 to 600 nm and a tail continuing beyond 700 nm, and said spectrum of the light emitted from said phosphor and said spectrum of the light emitted from said LED chip overlap with each other to make a continuous combined spectrum.

7. The light emitting diode according to claim 6, wherein said spectrum of the light emitted from said phosphor has a peak in the range from 530 to 570 mm and a tail continuing beyond 700 nm.

8. The light emitting diode according to claim 6, wherein a color of said combined spectrum is white.

9. The light emitting diode according to claim 1, wherein said phosphor comprises two or more kinds of fluorescent materials.

10. The light emitting diode according to claim 1, wherein said phosphor comprises an yttrium-aluminum-garnet fluorescent material containing Y and Al.

11. The light emitting diode according to claim 1, wherein said phosphor has a crystal structure.

12. The light emitting diode according to claim 1, wherein said LED chip comprises a light emitting layer of single quantum well or multi quantum well structure.

13. The light emitting diode according to claim 1, wherein said LED chip comprises InGaN.

14. The light emitting diode according to claim 1, wherein said LED chip comprises a sapphire substrate.

15. The light emitting diode according to claim 1, wherein said transparent material is selected from the group consisting of epoxy resin, urea resin, silicone resin and glass.

16. The light emitting diode according to claim 1, wherein said transparent material contains a dispersant.

17. The light emitting diode according to claim 15, wherein said dispersant is selected from the group consisting of barium titanate, titanium oxide, aluminum oxide and silicon dioxide.

18. The light emitting diode according to claim 1, wherein said transparent material contains a color agent.