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

• US 7,422,504 B2
• Filed: 06/03/2005
• Issued: 09/09/2008
• Est. Priority Date: 09/03/2001
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (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): Ton; Toan
• Assistant Examiner(s): Won; Bumsuk
• Application Number:
  US11/143,660
• Publication Number:
  US 20050227569A1
• Time in Patent Office: 1,194 Days
• Field of Search: 313498-512, 445/14, 445/24
• US Class Current: 445/24
• 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-xBa_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 method for fabricating a light-emitting semiconductor device including:

a blue-light-emitting device emitting light having a main emission peak in the wavelength range greater than 430 nm and less than or equal to 500 nm; and

a luminescent layer including a yellow/yellowish phosphor which absorbs blue light emitted by the blue-light-emitting device to emit a fluorescence having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive, and having a structure in which the blue light emitted by the blue-light-emitting device 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 emitting white light,

the method being characterized by comprising the steps of;

a) covering at least a light-extracting surface of the blue-light-emitting device with a phosphor paste including the yellow/yellowish phosphor which has an absolute specific gravity in the range from 3.0 to 4.65, both inclusive, and emits light having a main emission peak in the wavelength range from 560 nm to 600 nm, both inclusive, at room temperature, and with a resin which has an absolute specific gravity in the range greater than or equal to 0.8 and less than or equal to the absolute value of the yellow/yellowish phosphor; and

b) curing the phosphor paste, thereby forming the luminescent layer,

wherein in the step a), a phosphor including, as a base material, a compound containing at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Sc, lanthanoid, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Zn, B, Al, Ga, In, Si, Ge, Sn and P and at least one element selected from the group consisting of O, S, Se, F, Cl and Br is used as the yellow/yellowish phosphor, wherein the phosphor contains substantially no yttrium.

2. The method of claim 1, characterized in that in the step a), a yellow/yellowish phosphor having a particle size in the range from 0.5 μ

m to 30 μ

m, both inclusive, is used as the yellow/yellowish phosphor.

3. The method of claim 1 or 2, characterized in that in the step a), a silicate phosphor containing, as a main component, at least one type of a compound expressed by the chemical formula

(Sr_1-a1-b1-xBa_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

1) is used as the yellow/yellowish phosphor.

4. The method of claim 1, characterized in that in the step a), ultra-fine particles including primary particles having an average particle size in the range from 1 nm to 100 nm, both inclusive, are previously included in the phosphor paste.

5. The method of claim 1, wherein

in the step b), the phosphor paste is cured while a vibration is applied to the phosphor paste.

6. The method of claim 1, wherein

in the step b), the phosphor paste is cured while the phosphor paste is turned over.

7. The method of claim 1, wherein wherein in the step b), curing the phosphor paste is performed a plurality of times.

8. The method of claim 1, wherein

in the step a), a light-extracting surface of the blue-light-emitting device is covered with a phosphor paste including a resin and phosphor particles and having a viscosity in the range from 1 Pa·

S to 100 Pa·

S, both inclusive; and

wherein in the step b), curing the phosphor paste is performed a plurality of times.

9. The method of claim 1, wherein

in the step b), the phosphor paste is cured with ultraviolet radiation.

10. The method of claim 1, wherein

in the step b), the phosphor paste is cured while the phosphor paste is agitated.

11. The method of claim 1, wherein

in the step a), at least the light-extracting surface of the blue-light-emitting device is covered, with a phosphor paste including a translucent resin and phosphor particles, which includes a yellow/yellowish phosphor and to whose surfaces positively charged substances are attached;

and

wherein in the step a), as the yellow/yellowish phosphor, a silicate phosphor which is a yellow/yellowish phosphor absorbing light emitted by the blue-light-emitting device to emit light having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive, and which contains, as a main component, at least one type of a compound expressed by the chemical formula

(Sr_1-a1-b1-xBa_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

1) is used.

12. The method of claim 1, wherein p1 in the step a), a phosphor including, as a base material, a compound containing at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Sc, Zn, B, Al, Ga, In, Si, Ge, Sn and P and at least one element selected from the group consisting of O, F, Cl and Br is used as the yellow/yellowish phosphor.

13. The method of claim 1 or 12, wherein

in the step a), as the yellow/yellowish phosphor, a yellow/yellowish phosphor emitting light having a main emission peak in the wavelength range from 560 nm to 575 nm, both inclusive is used.

14. The method of claim 1 or 12, wherein

a luminescent layer has a substantial thickness in the range from 50 μ

m to 1000 μ

m, both inclusive, where at least a main light-extracting surface of the blue-light-emitting device is located.

15. The method of claim 1 or 12, wherein

the upper surface of a portion of the luminescent layer located at least on a main light-extracting surface of a blue-light-emitting diode is flat and substantially parallel to the main light-extracting surface.

16. A method for fabricating a light-emitting semiconductor device, characterized by comprising the steps of:

a) covering at least a light-extracting surface of a blue-light-emitting device which emits light having a main emission peak in the wavelength range greater than 430 nm and less than or equal to 500 nm, with a first phosphor paste including a base material of a translucent resin and phosphor particles including a yellow/yellowish phosphor;

b) covering the first phosphor paste with a second phosphor paste including at least a translucent resin and containing a yellow/yellowish phosphor at a concentration lower than that in the first phosphor paste, after the step a) has been performed; and

c) curing the first and second phosphor pastes,

wherein in the step a), as the yellow/yellowish phosphors, a silicate phosphor which is a yellow/yellowish phosphor absorbing light emitted by the blue-light-emitting device to emit light having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive, and which contains, as a main component, at least one type of a compound expressed by the chemical formula

(Sr_1-a1-b1-xBa_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

1) is used.