LIGHT SOURCE UNIT AND PROJECTOR

• US 20090284148A1
• Filed: 05/13/2009
• Published: 11/19/2009
• Est. Priority Date: 05/15/2008
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: IWANAGA, Masakuni
• Granted Patent: US 8,354,790 B2
• Time in Patent Office: Days
• US Class Current: 313/506
• CPC Class Codes: F21V 9/45 by adjustment of photoluminescent elements
• CPC Class Codes: G02B 26/008 in the form of devices for effecting sequential colour changes, e.g. colour wheels
• CPC Class Codes: G02B 27/1073 characterized by manufacturing or alignment methods
• CPC Class Codes: G02B 7/006 Filter holders
• CPC Class Codes: G03B 21/16 Cooling; Preventing overheating
• CPC Class Codes: G03B 21/204 using secondary light emission, e.g. luminescence or fluorescence using different colours G03B33/00; if related to video signals H04N9/3197
• CPC Class Codes: H04N 9/3114 by using a sequential colour filter producing one colour at a time

Abstract

A projector comprises a light source unit 63, a display device, a cooling fan, a light source side optical system for guiding light from the light source unit 63 to the display device, a projection side optical system for projecting an image emitted from the display device on to a screen, and a projector control unit for controlling the light source unit 63 and the display device. In addition, this light source unit 63 has a plurality of fan-shaped segment areas on a circular transparent base material 130 which can be controlled to rotate, layers 131 of different phosphors which emit light of predetermined wavelength bands by receiving excitation light being disposed on at least two of the segment areas on the transparent base material 130, and comprises an excitation light source 72 which shines excitation light within a visible light wavelength band on to the phosphors.

Claims

1. A light source unit having a plurality of segment areas on a transparent base material which can be controlled to rotate, layers of different phosphors for emitting light of predetermined wavelength bands respectively by receiving excitation light being disposed on at least two of the segment areas of the transparent base material, and comprising an excitation light source for shining excitation light within a visible light wavelength range on to the phosphors.

2. A light source unit as set forth in claim 1, wherein

the transparent base material is circular.

3. A light source unit as set forth in claim 1, wherein

a transmissive area which transmits the excitation light is provided on at lease one of the segment areas on the transparent base material.

4. A light source unit as set forth in claim 1, wherein

the transparent base material is formed of a glass base material or a transparent resin base material.

5. A light source unit as set forth in claim 1, wherein

a dichroic layer which transmits the excitation light and reflects light of other wavelength bands is formed on a surface of a side of the transparent base material where the phosphor layers are disposed.

6. A light source unit as set forth in claim 1, wherein

a reflectionless coating layer is formed on a surface of an opposite side of the transparent base material to the side thereof where the phosphor layers are disposed.

7. A light source unit as set forth in claim 1, wherein

the excitation light source shines light of a wavelength band whose wavelength is shorter than that of the light of predetermined wavelength bands which is emitted by the respective phosphors.

8. A light source unit as set forth in claim 1, wherein

a diffusion layer which imparts a diffusion effect is formed on the segment area of the transparent base material on which no such phosphor layer as the phosphor layers is disposed.

9. A light source unit as set forth in claim 1, wherein

the excitation light source is a light emitting diode or a laser emitter which shines light of a wavelength band of blue.

10. A light source unit as set forth in claim 1, wherein

each phosphor emits light of a wavelength band of one of

the primary colors of light or a complementary color by receiving the excitation light.

11. A light source unit, as set forth in claim 1, wherein

the transparent base material has a segment area on which the phosphor layer which emits light of a wavelength band of red is disposed and a segment area on which the phosphor layer which emits light of a wavelength band of green is disposed.

12. A light source unit as set forth in claim 1, wherein

the transparent base material has a segment area on which the phosphor layer which emits light of a wavelength band of yellow is disposed.

13. A light source unit as set forth in claim 1, wherein

the phosphor layers are formed on the transparent base material in a constant disposing pattern in a repeated fashion along a circumferential direction of the transparent base material.

14. A light source unit as set forth in claim 1, wherein

an auxiliary transparent base material which can be controlled to rotate in synchronism with the transparent base material is disposed concentrically with the transparent base material, and wherein

an excitation light reflecting layer which reflects the excitation light and transmits the light of wavelength bands which is emitted by the phosphors is formed on a surface of a side of the auxiliary transparent base material which faces the transparent base material in such a manner as to correspond to the respective segment areas on the transparent base material.

15. A light, source unit as set forth in claim 14, wherein

a reflectionless coating layer is formed on a surface of an opposite side of the auxiliary transparent base material to the side thereof which faces the transparent base material.

16. A light source unit as set forth in claim 1, having an auxiliary excitation light source together with the excitation light source, and wherein

the transparent base material having the segment areas is disposed between the excitation light source and the auxiliary excitation light source.

17. A projector comprising a light source unit, a display device, a light source side optical system for guiding light from one light source unit to the display device, a projection side optical system for projecting an image emitted from the display device on to a screen, and a projector control unit for controlling the light source unit and the display device, wherein the light source unit is a light source unit as set forth in claim 1.