LIGHT-EMITTING DEVICE, WHITE LIGHT-EMITTING DEVICE, ILLUMINATOR, AND IMAGE DISPLAY

• US 20090140630A1
• Filed: 03/17/2006
• Published: 06/04/2009
• Est. Priority Date: 03/18/2005
• Status: Active Grant

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: Takeshita, Kimiya, Kijima, Naoto, Shimomura, Yasuo, Kaneda, Hideaki
• Granted Patent: US 8,269,410 B2
• Time in Patent Office: Days
• US Class Current: 313/498
• CPC Class Codes: C09K 11/661 Chalcogenides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: C09K 11/77742 Silicates
• CPC Class Codes: C09K 11/778 Borates
• CPC Class Codes: C09K 11/7784 Chalcogenides
• CPC Class Codes: C09K 11/7788 Oxyhalogenides
• CPC Class Codes: C09K 11/7794 Vanadates; Chromates; Molybdates; Tungstates
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/48091 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 2224/73265 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 2924/12036 : PN diode
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/181 : Encapsulation
• 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 33/502 : Wavelength conversion materials
• CPC Class Codes: Y02B 20/00 : Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

To achieve a light-emitting device emitting light with high brightness, closer to natural light, and less color shift due to a small change in intensity of emitted light, in a light-emitting device including a light source emitting light by driving current and at least one wavelength-converting material absorbing at least part of the light from the light source and emitting light having a different wavelength, the color coordinate x₁(17.5) and the color coordinate y₁(17.5) of the light emitted at a driving current density of 17.5 A/cm² and the color coordinate x₁(70) and the color coordinate y₁(70) of the light emitted at a driving current density of 70 A/cm² satisfy the following Expressions (D) and (E):

−0.006≦x₁(17.5)−x₁(70)≦0.006  (D),

−0.006≦y₁(70)−y₁(70)≦0.006  (E).

Claims

1. A light-emitting device comprising a light source emitting light by driving current and at least one wavelength-converting material absorbing at least part of the light from the light source and emitting light having a different wavelength, wherein

the color coordinate x₁(17.5) and the color coordinate y₁(17.5) of the light emitted at a driving current density of 17.5 A/cm², and the color coordinate x₁(70) and the color coordinate y₁(70) of the light emitted at a driving current density of 70 A/cm² satisfy the following Expressions (D) and (E):

−

0.006≦

x₁(17.5)−

x₁(70)≦

0.006 

 

(D), and

−

0.006≦

y₁(17.5)−

y₁(70)≦

0.006 

 

(E).

4. The light-emitting device according to any one of claims 1 to 3, wherein

the wavelength-converting material is a mixture of two or more phosphors;

and

the brightness BR(25), the color coordinate x₂(25), and the color coordinate y₂(25) of the fluorescence obtained by exciting the phosphor mixture with blue light having a peak wavelength of 455 nm at 25°

C., and the brightness BR(125), the color coordinate x₂(125), and the color coordinate y₂(125) of the fluorescence obtained by exciting the phosphor mixture with the blue light at 125°

C. satisfy following Expressions (A), (B), and (C);

0.85≦

BR(125)/BR(25)≦

1.15 

 

(A),

−

0.03≦

x₂(25)−

x₂(125)≦

0.03 

 

(B), and

−

0.03≦

y₂(25)−

y₂(125)≦

0.03 

 

(C).

5. The light-emitting device according to any one of claims 1 to 4, wherein the wavelength-converting material contains at least one green phosphor having a fluorescence intensity peak value in the wavelength range of 500 nm to 550 nm.

6. The light-emitting device according to any one of claims 1 to 5, wherein the wavelength-converting material contains at least one red phosphor having a fluorescence intensity peak value in the wavelength range of 610 nm to 680 nm.

7. A lighting system comprising the light-emitting device according to any one of claims 1 to 6.

8. A display comprising the light-emitting device according to any one of claims 1 to 6.

2. A light-emitting device comprising a light source emitting light by driving current and at least one wavelength-converting material absorbing at least part of the light from the light source and emitting light having a different wavelength, wherein

the light-emitting device has an emission efficiency of 32 lm/W or more and a general color rendering index Ra of 85 or more;

and

the color coordinate x₁(17.5) and the color coordinate y₁(17.5) of the light emitted at a driving current density of 17.5 A/cm², the color coordinate x₁(70) and the color coordinate y₁(70) of the light emitted at a driving current density of 70 A/cm², and the shift amounts [x₁(17.5)−

x₁(70)] and [y₁(170.5)−

y₁(70)] in the color coordinates x and y satisfy the following Expressions (F) and (G);

−

0.01≦

x₁(17.5)−

x₁(70)≦

0.01 

 

(F), and

−

0.01≦

y₁(17.5)−

y₁(70)≦

0.01 

 

(G).

3. The light-emitting device according to claim 2, wherein the special color rendering index R₉ is 64 or more.

9. A white-light emitting device comprising a light source and at least one wavelength-converting material absorbing at least part of the light from the light source and emitting light having a different wavelength, wherein

the white-light emitting device emits white light containing the light emitted by the wavelength-converting material;

and

the maximum intensity of the emission spectrum of the white light at the prescribed wavelength range of 500 nm 650 nm is not higher than 150% of the minimum intensity in the prescribed wavelength range.

10. The white-light emitting device according to claim 9, wherein

the brightness of the wavelength-converting material at 100°

C. is not less than 80% of that at 25°

C.

11. The white-light emitting device according to claim 9 or 10, wherein the absorption efficiency of the wavelength-converting material for the light with the peak wavelength emitted by the light source is 50% or more, and the internal quantum efficiency of the wavelength-converting material is 40% or more.

12. A lighting system comprising the white-light emitting device according to any one of claims 9 to 11.

13. A display comprising a red pixel and at least one non-red pixel, wherein

the red pixel comprises:

a red light-emitting device including light-emitting element for a red-pixel and a red phosphor having a temperature-dependent coefficient of 85 or more;

the non-red pixel comprises;

a blue pixel including light-emitting element for a blue-pixel; and

/or

a green pixel including light-emitting element for a green-pixel and a green phosphor having a temperature-dependent coefficient of 85 or more, and

when I(R,25) and I(R,100) denote the emission intensity of the red pixel at 25°

C. and at 100°

C., respectively, and when I(N,25) and I(N,100) denote the emission intensity of the non-red pixel at 25°

C. and at 100°

C., respectively, the ratio of the value I(N,100)/I(N,25) to the value I(R,100)/I(R,25) is 90% or more.