Fluorescent member, and illumination device and display device including the same

• US 20050012076A1
• Filed: 08/28/2003
• Published: 01/20/2005
• Est. Priority Date: 09/20/2002
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Morioka, Tatsuya
• Granted Patent: US 7,022,260 B2
• Time in Patent Office: Days
• US Class Current: 252/301.40R
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 11/565 with zinc cadmium
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• 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

Abstract

A fluorescent member includes a plurality of particles dispersed in a medium. Each particle includes a core and a coating layer covering the core. The core is formed of a semiconductor which absorbs excitation light and emits light of a wavelength different from that of the excitation light. Each particle is made to have a particle size for causing Mie scattering with respect to the excitation light. Thus, a fluorescent member excellent in light conversion efficiency can be obtained.

Claims

1. A fluorescent member comprising a plurality of particles dispersed in a medium, wherein

each said particle includes a core and a coating layer covering the core,

said core is formed of a semiconductor for absorbing excitation light and emitting light having a wavelength different from a wavelength of the excitation light, and

said particle has a particle size for causing Mie scattering with respect to said excitation light.

3. The fluorescent member according to claim 1, wherein said coating layer is formed of a semiconductor different in composition or composition ratio from said core.

4. The fluorescent member according to claim 1, wherein said fluorescent member includes a plurality of cores different in composition or composition ratio from each other.

5. The fluorescent member according to claim 1, wherein said core is formed of a semiconductor selected from In_xGa_yAl_1-x-yN, Zn_xMg_yCd_1-x-ySe_vS_1-v, Si, and C.

6. The fluorescent member according to claim 1, wherein said fluorescent member includes a plurality of cores same in composition ratio and different in size with each other.

7. The fluorescent member according to claim 1, wherein each said particle includes a plurality of cores for emitting light of the same wavelength and a coating layer covering the cores.

8. The fluorescent member according to claim 1, wherein each said particle includes a plurality of cores for emitting lights of different wavelengths and a coating layer covering the cores.

9. An illumination device comprising the fluorescent member of claim 1 and a light source for exciting the fluorescent member.

10. A display device comprising the fluorescent member of claim 1, a light source for exciting the fluorescent member, and light control means for controlling at least one of intensity of excitation light directed to said fluorescent member and intensity of light emitted from said fluorescent member.

2. A fluorescent member comprising a plurality of particles dispersed in a medium, wherein

each said particle includes a core and a coating layer covering the core,

said core is formed of a semiconductor for absorbing excitation light and emitting light having a wavelength different from a wavelength of the excitation light, and

a particle size D(μ

m) of said particle and a wavelength λ

(μ

m) of said excitation light satisfy a relation of D/λ

≧

0.2.