LIGHT SOURCE UNIT UTILIZING LASER FOR LIGHT SOURCE AND PROJECTOR

• US 20100328625A1
• Filed: 06/29/2010
• Published: 12/30/2010
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Ogawa, Masahiro, Miyazaki, Takeshi
• Granted Patent: US 8,308,306 B2
• Time in Patent Office: Days
• US Class Current: 353/85
• CPC Class Codes: G02B 26/008 in the form of devices for effecting sequential colour changes, e.g. colour wheels
• 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: G03B 33/08 Sequential recording or projection G03B33/02, G03B33/04, G03B33/06 take precedence
• CPC Class Codes: H04N 9/3117 by using a sequential colour filter producing two or more colours simultaneously, e.g. by creating scrolling colour bands
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129
• CPC Class Codes: H04N 9/3164 using multiple light sources

Abstract

A light source unit includes a light emitting plate which has a plurality of segment areas and in which a luminescent material layer which emits light having a predetermined wavelength band by receiving excitation light and a transmissive portion which transmits light are formed on at least the plurality of segment areas, a primary light source for emitting excitation light on to the luminescent material, a secondary light source for emitting light having a wavelength band which differs from those of luminescent light emitted from the luminescent material layer and excitation light emitted from the primary light source, a light guiding optical system for guiding light emitted from the light emitting plate and light emitted from the secondary light source to the same optical path, and a light source control means for controlling the emission of light from the primary light source and the secondary light source.

Claims

1. A light source unit comprising:

a primary light source for emitting excitation light;

a light emitting plate which has a plurality of segment areas and in which a luminescent material layer which emits light having a predetermined wavelength band by receiving the excitation light and a transmissive portion which transmits light are formed on at least the plurality of segment areas;

a secondary light source for emitting light having a wavelength band which differs from those of luminescent light emitted from the luminescent material layer and excitation light emitted from the primary light source;

a light guiding optical system for guiding light emitted from the light emitting plate and light emitted from the secondary light source to a same optical path; and

light source control means for controlling the emission of light from the primary light source and the secondary light source.

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

the light emitting plate is a wheel which is made up of a base material whose rotation can be controlled.

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

the light source control means turns off the primary light source so as to prevent light from the primary light source from being shone on to at least one boundary between the adjacent segment areas.

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

the secondary light source is turned on while the primary light source is turned off.

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

the primary light source is a laser emitter which emits laser light having a wavelength band of blue.

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

the luminescent material is a luminescent material which emits at least light having a wavelength band of green by receiving excitation light.

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

a diffuse layer is formed on the transmissive portion of the light emitting plate which diffuses light from the primary light source.

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

a luminescent material layer is formed on the transmissive portion of the light emitting plate which emits light having a wavelength band which is different from light having a predetermine wavelength band which the luminescent material layer emits by receiving the excitation light from the primary light source.

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

the secondary light source is a light emitting diode which emits light having a wavelength band of red.

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

a dichroic layer is formed on a surface of the segment area of the transparent base material on which the luminescent material layer is to be disposed, the dichroic layer being adapted to transmit the excitation light and reflect light having other wavelength bands.

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

a dichroic mirror is disposed in a position where an optical axis of the primary light source and an optical axis of the secondary light source intersect each other at right angles, the dichroic mirror being adapted to transmit light from the light emitting plate and reflect light from the secondary light source or adapted to reflect light from the light emitting plate and transmit light from the secondary light source, and wherein

light emitted from the secondary light source is prevented from entering the light emitting plate.

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

the light source control means is configured so as not only to control to turn on the primary light source and the secondary light source individually separately but also to control to turn on the primary light source and the secondary light source simultaneously so that light emitted from the light emitting plate by receiving light from the primary light source and light emitted from the secondary light source are combined together only for a predetermined length of time.

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

a dichroic mirror is disposed in a position where an optical axis of the primary light source and an optical axis of the secondary light source intersect each other at right angles, the dichroic mirror being adapted to transmit light from the primary light source and reflect light from the secondary light source or adapted to reflect light from the primary light source and transmit light from the secondary light source, and wherein

light from the secondary light source is made to pass through the transmissive portion of the light emitting plate.

14. A projector characterized by comprising the light source unit set forth in claim 1, a light source apparatus, a display device, a light source side optical system for guiding light from the light source apparatus to the display device, a projection side optical system for projecting an image emitted from the display device on to a screen, and projector control means for controlling the light source apparatus and the display device.