Semiconductor light emitting device, light emitting apparatus and production method for semiconductor light emitting device

• US 20040104391A1
• Filed: 09/03/2003
• Published: 06/03/2004
• Est. Priority Date: 09/03/2001
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Sakanoue, Kei, Iwama, Katsuaki, Hanada, Yasuyuki, Oshio, Shozo, Kamei, Hidenori, Ikeda, Tadaaki, Maeda, Toshihide, Kitahara, Hiromi
• Granted Patent: US 7,023,019 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• 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, characterized by comprising:

a blue-light-emitting device having a light-extracting surface and emitting blue light from the light-extracting surface; and

a luminescent layer provided to cover at least the light-extracting surface of the blue-light-emitting device and including a yellow/yellowish phosphor which absorbs blue light emitted by the blue-light-emitting device to emit a yellow/yellowish fluorescence,

wherein the yellow/yellowish phosphor is a silicate phosphor containing, as a main component, at least one type of a compound expressed by the chemical formula;

(Sr<sub>1−

a1−

b1−

x</sub>Ba_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

1).

2. The light-emitting semiconductor device of claim 1, characterized in that the blue-light-emitting device is a device selected from the group consisting of a blue-light-emitting diode, a laser diode, a surface emitting laser diode, an inorganic electroluminescence device and an organic electroluminescence device.

3. The light-emitting semiconductor device of claim 1, characterized in that the Ca mole fraction b1 of the yellow/yellowish phosphor is a mole fraction b2 in the range 0≦

b2≦

0.6.

4. The light-emitting semiconductor device of any one of claims 1 to 3, characterized in that the blue-light-emitting device emits light having a main emission peak in the wavelength range greater than 430 nm and less than or equal to 500 nm.

5. The light-emitting semiconductor device of claim 4, characterized in that the yellow/yellowish phosphor emits a fluorescence having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive.

6. The light-emitting semiconductor device of any one of claims 1 to 5, characterized in that the silicate phosphor has an orthorhombic structure.

7. The light-emitting semiconductor device of claim 6, characterized in that the blue-light-emitting device is a blue-light-emitting inorganic device 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.

8. The light-emitting semiconductor device of claim 7, characterized in that the color of light emitted by the light-emitting semiconductor device has an emission chromatically point (x, y) in the ranges 0.21≦

x≦

0.48 and 0.19≦

y≦

0.45, respectively, in a CIE chromaticity diagram.

9. The light-emitting semiconductor device of any one of claims 1 to 8, characterized in that 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.

10. The light-emitting semiconductor device of claim 9, characterized in that 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.

11. The light-emitting semiconductor device of claim 10, characterized in that 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 and 0<

x<

1).

12. The light-emitting semiconductor device of claim 8, characterized in that the silicate phosphor is made of a plurality of compounds mutually differing in composition and each emitting yellow/yellowish light having a main emission peak in the wavelength range from 550 nm to 600 nm, both inclusive.

13. The light-emitting semiconductor device of any one of claims 1 to 12, characterized in that:

the luminescent layer includes a translucent resin as a base material; and

the yellow/yellowish phosphor is present in the form of dispersed particles in the base material.

14. The light-emitting semiconductor device of any one of claims 1 to 12, characterized in that the luminescent layer is made by forming the silicate phosphor.

15. The light-emitting semiconductor device of any one of claims 1 to 14, characterized by having a structure in which 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 producing white light.

16. The light-emitting semiconductor device of any one of claims 1 to 15, characterized by further including a substrate,

wherein the blue-light-emitting device is flip-chip mounted on the substrate, and

wherein the luminescent layer functions as a molding resin for molding the blue-light-emitting device.

17. The light-emitting semiconductor device of claim 16, characterized in that the substrate includes a Zener diode.

18. The light-emitting semiconductor device of any one of claims 1 to 15, characterized by further including a mount lead with a cup,

wherein the blue-light-emitting device is mounted in the cup, and

wherein the luminescent layer is provided within the cup.

19. The light-emitting semiconductor device of any one of claims 1 to 15, characterized by further including a casing for placing the blue-light-emitting device therein,

wherein the luminescent layer is provided within the casing.

20. The light-emitting semiconductor device of any one of claims 1 to 19, characterized in that the luminescent layer has a substantial thickness in the range from 50 μ

m to 1000 μ

m, both inclusive, where the light extraction surface of the blue-light-emitting device is located.

21. The light-emitting semiconductor device of claim 20, characterized in that the upper surface of a portion of the luminescent layer located at least on the light-extracting surface of the blue-light-emitting device is flat and substantially parallel to the light-extracting surface.

22. The light-emitting semiconductor device of any one of claims 1 to 21, characterized in that:

the blue-light-emitting device is provided in a plural presence; and

the luminescent layer is provided to cover respective light-emitting surfaces of the plurality of blue-light-emitting devices.

23. A light-emitting system, characterized by comprising:

a blue-light-emitting device emitting blue light;

a luminescent layer including a yellow/yellowish phosphor which absorbs blue light emitted by the blue-light-emitting device to emit a yellow/yellowish fluorescence; and

a supporter for supporting the blue-light-emitting device and the luminescent layer,

wherein the yellow/yellowish phosphor is a silicate phosphor containing, as a main component, at least one type of a compound expressed by the chemical formula;

(Sr<sub>1−

a1−

b1−

x</sub>Ba_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

1).

24. The light-emitting system of claim 23, characterized in that the blue-light-emitting device is a blue-light-emitting diode or a surface emitting laser diode.

25. The light-emitting system of claim 23, characterized in that the Ca mole fraction b1 of the yellow/yellowish phosphor is a mole fraction b2 in the range 0≦

b2≦

0.6.

26. The light-emitting system of any one of claims 23 to 25, characterized in that 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.

27. The light-emitting system of any one of claims 23 to 26, characterized in that 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.

28. The light-emitting system of claim 27, characterized in that 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_b1Eu_x)₂SiO₄

(where 0≦

a3≦

1, 0≦

b3≦

1 and 0<

x<

1).

29. The light-emitting system of any one of claims 23 to 28, characterized by further including a substrate member,

wherein the blue-light-emitting device is flip-chip mounted on the substrate member, and

wherein the luminescent layer functions as a molding resin for molding the blue-light-emitting device.

30. The light-emitting system of claim 29, characterized in that the substrate member includes a Zener diode.

31. The light-emitting system of any one of claims 23 to 28, characterized by further including a mount lead with a cup,

wherein the blue-light-emitting device is mounted in the cup, and

wherein the luminescent layer is provided within the cup.

32. The light-emitting system of any one of claims 23 to 27, characterized by further including a casing for placing the blue-light-emitting device therein,

wherein the luminescent layer is provided within the casing.

33. The light-emitting system of any one of claims 23 to 31, characterized in that:

the blue-light-emitting device is provided in a plural presence; and

the luminescent layer is provided to cover respective light-emitting surfaces of the plurality of blue-light-emitting devices.

34. 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,

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, Y, 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.

35. The method of claim 34, 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.

36. The method of claim 34 or 35, 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

(Sr₁₋

a1−

b1−

xBa_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

8)

is used as the yellow/yellowish phosphor.

37. The method of any one of claims 34 to 36, 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.

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

a) covering a light-extracting surface of a blue-light-emitting device with a phosphor paste including a resin and phosphor particles; and

b) curing the phosphor paste while applying a vibration to the phosphor paste.

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

a) covering a light-extracting surface of a blue-light-emitting device with a phosphor paste including a resin and phosphor particles; and

b) curing the phosphor paste while turning over the phosphor paste.

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

a) covering a light-extracting surface of a blue-light-emitting device with a phosphor paste including a resin and phosphor particles; and

b) curing the phosphor paste,

wherein the steps a) and b) are performed a plurality of times.

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

a) covering a light-extracting surface of a blue-light-emitting device 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

b) curing the phosphor paste,

wherein the steps a) and b) are performed a plurality of times.

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

a) covering a light-extracting surface of a blue-light-emitting device with a phosphor paste including a resin and phosphor particles; and

b) curing the phosphor paste with ultraviolet radiation.

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

a) covering a light-extracting surface of a blue-light-emitting device with a phosphor paste including a resin and phosphor particles; and

b) curing the phosphor paste while agitating the phosphor paste.

44. 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<sub>1−

a1−

b1−

x</sub>Ba_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

1)

is used.

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

a) attaching phosphor particles including a yellow/yellowish phosphor to 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;

b) covering at least the light-extracting surface of the blue-light-emitting device with a translucent resin, after the step a) has been performed; and

c) curing the resin,

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<sub>1−

a1−

b1−

x</sub>Ba_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

1)

is used.

46. The method of claim 45, characterized in that in the step a), the yellow/yellowish phosphor particles are sprinkled on the blue-light-emitting device.

47. The method of claim 45, characterized in that in the step a), the blue-light-emitting device is immersed in a suspension containing phosphor particles, including a yellow/yellowish phosphor, and a volatile solvent, and then the solvent is evaporated.

48. 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 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

b) curing the phosphor paste,

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<sub>1−

a1−

b1−

x</sub>Ba_a1Ca_b1Eu_x)₂SiO₄

(where 0≦

a1≦

0.3, 0≦

b1≦

0.8 and 0<

x<

1)

is used.