Video Projector Using Coherent Light Source

• US 20080036921A1
• Filed: 11/04/2005
• Published: 02/14/2008
• Est. Priority Date: 11/08/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Yokoyama, Toshifumi, Furuya, Hiroyuki, Yamamoto, Kazuhisa
• Granted Patent: US 7,866,822 B2
• Time in Patent Office: Days
• US Class Current: 348/756
• CPC Class Codes: G03B 21/145 Housing details, e.g. position adjustments thereof
• CPC Class Codes: G03B 21/16 Cooling; Preventing overheating
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161
• CPC Class Codes: H04N 9/3144 Cooling systems cooling of liquid crystal cells in general G02F1/133382; cooling of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/16
• CPC Class Codes: H04N 9/315 Modulator illumination systems general applications of lighting devices F21V; general optical systems G02B; lamp houses for projectors not peculiar to the presence of an electronic spatial light modulator G03B21/20

Abstract

In the video projector of the present invention, a fiber part (3b) of a fiber laser (3) is disposed so as to draw a circulating orbit of more than one circulation along the inner wall of the projector housing (1). Further, an FBG (14) which constitutes the fiber laser (3) is fixed so that its shape is not changed. Furthermore, a pump LD part (3a) of the fiber laser (3) is disposed apart from the SHG element (5). As a result, the video projector can be miniaturized, and thereby the portability and installment of the video projector are facilitated. Further, the output stabilization of the fiber laser can be realized by preventing the shape change of the FBG. Furthermore, by disposing the SHG element apart from the pump LD part which forms a heat source, the temperature change of the SHG element is suppressed and the wavelength conversion efficiency by the SHG element is enhanced.

Claims

1. A video projector for projecting video on a screen, comprising:

a fiber laser which comprises a pump LD part for emitting a laser beam and a fiber part for amplifying the emitted laser beam from the pump LD part; and

an SHG element for converting the wavelength of the emitted light from the fiber laser and outputting a projection light onto the screen, wherein,

said fiber part is arranged so as to draw a circulating orbit of more than one circulation along the inner wall of a projector housing.

2. The video projector as defined in claim 1, wherein said SHG element and said pump LD part or the projector housing which includes said pump LD part are separated, and said pump LD part is arranged in a state of contacting the inner wall of the projector housing.

3. The video projector as defined in claim 2, wherein said SHG element and said pump LD part are separated by more than 3 cm.

4. The video projector as defined in claim 1, wherein a fiber Bragg grating which constitutes said fiber part is fixed so that its shape is not changed.

5. The video projector as defined in claim 1, wherein control for suppressing the temperature change of the fiber Bragg grating constituting said fiber part is carried out.

6. The video projector as defined in claim 1, wherein the fiber Bragg grating which constitutes said fiber part is isolated from air in the projector housing.

7. The video projector as defined in claim 1, wherein a marker for identifying the polarization direction is formed at a part of said fiber part.

8. The video projector as defined in claim 1 comprises a photoelectric conversion element for converting a fundamental wave which was not wavelength converted by said SHG element into electric power.

9. A video projector for projecting video on a screen comprises a fiber laser comprising a pump LD part for irradiating a laser beam and a fiber part for amplifying an irradiation beam from the pump LD part, wherein said pump LD part is arranged external to the projector housing.

10. The video projector as defined in claim 9, wherein said fiber part is incorporated in the power code of the video projector, and said pump LD part is incorporated in a connector part of said power code.

11. The video projector as defined in claim 9 comprises a photoelectric conversion element for converting a light which was not used in wavelength conversion, among the irradiation lights from said fiber laser, into electric power.

12. A video projector for projecting video on a screen comprises:

a fundamental wave light source for emitting a fundamental wave; and

an SHG element for converting an emitted light from the fundamental wave light source and outputting a projection light on the screen, wherein,

the video projector comprises a photoelectric conversion element for converting a fundamental wave which was not wavelength converted by said SHG element into electric power.

13. The video projector as defined in claim 12, wherein said photoelectric conversion element is made of a material using either of Si, Ge, Cds, InP, CdTe, GaAs, or AlSb.