Light-emitting semiconductor device, light-emitting system and method for fabricating light-emitting semiconductor device

• US 7,023,019 B2
• Filed: 09/03/2002
• Issued: 04/04/2006
• Est. Priority Date: 09/03/2001
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Oshio, Shozo, Kamei, Hidenori, Ikeda, Tadaaki, Sakanoue, Kei, Iwama, Katsuaki, Maeda, Toshihide, Kitahara, Hiromi, Hanada, Yasuyuki
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Nguyen, Dao H.
• Application Number:
  US10/469,740
• Publication Number:
  US 20040104391A1
• Time in Patent Office: 1,309 Days
• Field of Search: 257/79, 257/89, 257/99, 313/502, 313/503, 313/506
• US Class Current: 257/89
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/7735 Germanates
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: F21S 6/00 Lighting devices intended to be free-standing F21S9/00, F21S10/00, F21S13/12 take precedence lighting devices specially adapted to be transported from place to place, e.g. lighting devices carried on wheeled supports F21L; details of supports for lighting devices F21V21/00
• CPC Class Codes: F21S 6/003 for task lighting, e.g. for reading or desk work, e.g. angle poise lamps
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• 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 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• 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 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• 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 2924/12035 : Zener diode
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/12044 : OLED
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/54 : having a particular shape
• 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 chip-type light-emitting semiconductor device includes: a substrate 4; a blue LED 1 mounted on the substrate 4; and a luminescent layer 3 made of a mixture of yellow/yellowish phosphor particles 2 and a base material 13 (translucent resin). The yellow/yellowish phosphor particles 2 is a silicate phosphor which absorbs blue light emitted by the blue LED 1 to emit a fluorescence having a main emission peak in the wavelength range from 550 nm to 600 nm, inclusive, and which contains, as a main component, a compound expressed by the chemical formula: (Sr_{1−a1−b1−x}Ba_a1Ca_b1Eu_x)₂SiO₄ (0≦a1≦0.3, 0≦b1≦0.8 and 0<x<1). The silicate phosphor particles disperse substantially evenly in the resin easily. As a result, excellent white light is obtained.

Claims

1. A light-emitting semiconductor device comprising:

a blue-light-emitting diode which emits blue light, the blue-light-emitting diode having a light extraction surface; and

a luminescent layer which includes a yellow/yellowish phosphor that absorbs blue light emitted by the blue-light-emitting diode to emit a yellow/yellowish fluorescence,

wherein the luminescent layer is exposed on the blue-light-emitting diode,

the yellow/yellowish phosphor contains a compound expressed by the chemical formula;

(Sr<sub>1−

a1−

b2−

x</sub>Ba_a1Ca_b2Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b2≦

0.6, 0.005 <

x<

0.1),

the yellow/yellowish phosphor has a particle size in the range from 0.5 μ

m to 30 μ

m, both inclusive, and is made of a silicate phosphor having an orthorhombic structure, and

a portion of the luminescent layer located at least on the light extraction surface of the blue-light-emitting diode has a substantial thickness in the range from 50 μ

m to 1000 μ

m, both inclusive.

2. The light-emitting semiconductor device of claim 1, wherein the silicate phosphor has a particle size in the range from 1 μ

m to 20 μ

m, both inclusive.

3. The light-emitting semiconductor device of claim 1, wherein the luminescent layer has a substantial thickness in the range from 100 μ

m to 700 μ

m, both inclusive.

4. The light-emitting semiconductor device of claim 1, wherein the luminescent layer includes a base material made of a translucent resin and particles of the yellow/yellowish phosphor, and

the particles of the yellow/yellowish phosphor are dispersed throughout the base material.

5. The light-emitting semiconductor device of claim 4, wherein the luminescent layer is formed by curing a phosphor paste having the yellow/yellowish phosphor and the resin, and

the phosphor paste contains ultra-fine particles including primary particles having an average particle size in the range from 1 nm to 100 nm, both inclusive.

6. The light-emitting semiconductor device of claim 1, wherein the blue-light-emitting diode emits light having a main emission peak in the wavelength range greater than 430 nm and less than or equal to 500 nm.

7. The light-emitting semiconductor device of claim 6, wherein the yellow/yellowish phosphor emits light having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive.

8. The light-emitting semiconductor device of claim 7, wherein the blue-light-emitting diode is made of a semiconductor selected from the group consisting of a gallium nitride-based compound semiconductor, a zinc selenide semiconductor and a zinc oxide semiconductor.

9. The light-emitting semiconductor device of claim 8, wherein the color of light emitted by the light-emitting semiconductor device has an emission chromatical point (x, y) in the ranges 0.21≦

x≦

0.48 and 0.19≦

y≦

0.45, respectively, in a CIE chromaticity diagram.

10. The light-emitting semiconductor device of claim 9, wherein blue light emitted by the blue-light-emitting diode passes through the luminescent layer so that the color of the fluorescence emitted by the phosphor is added to the color of the blue light, thereby producing white light.

11. The light-emitting semiconductor device of claim 10, wherein the luminescent layer further includes a red/reddish phosphor having a main emission peak in the red/reddish wavelength range greater than 600 nm and less than or equal to 660 nm.

12. The light-emitting semiconductor device of claim 10, wherein the luminescent layer further includes a green/greenish phosphor having a main emission peak in the green/greenish wavelength range greater than or equal to 500 nm and less than 550 nm.

13. The light-emitting semiconductor device of claim 12, wherein the green/greenish phosphor is a silicate phosphor containing, as a main component, a compound expressed by the chemical formula:

(Sr<sub>1−

a3−

b3−

x</sub>Ba_a3Ca_b3Eu_x)₂SiO₄

(where 0≦

a3≦

1, 0≦

b3≦

1, 0<

x<

1).

14. The light-emitting semiconductor device of claim 10, wherein the luminescent layer includes a plurality of said silicate phosphors each of which emits yellow/yellowish light having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive and mutually differs in composition.

15. The light-emitting semiconductor device of claim 10, wherein the blue-light-emitting diode is a flip-chip-type blue-light-emitting diode,

the flip-chip-type blue-light-emitting diode is mounted on a submount element to be electrically connected thereto, and

the luminescent layer within which particles of the yellow/yellowish phosphor exist encapsulates the flip-chip-type blue-light-emitting diode.

16. The light-emitting semiconductor device of claim 10, wherein the blue-light-emitting diode is mounted in a cup provided in a mount lead to be electrically connected to the cup,

the luminescent layer within which particles of the yellow/yellowish phosphor exist is provided in the cup.

17. The light-emitting semiconductor device of claim 10, wherein the blue-light-emitting diode is placed in a casing, and

the luminescent layer within which particles of the yellow/yellowish phosphor exist is provided in the casing.

18. The light-emitting semiconductor device of claim 10, wherein the surface of the portion of the luminescent layer located at least on the main light-extracting surface of the blue-light-emitting diode is flat and parallel to the main light-extracting surface.

19. A light-emitting semiconductor system comprising the light-emitting semiconductor device of claim 1.