Video projector using coherent light source

• US 7,866,822 B2
• Filed: 11/04/2005
• Issued: 01/11/2011
• Est. Priority Date: 11/08/2004
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Yokoyama, Toshifumi, Furuya, Hiroyuki, Yamamoto, Kazuhisa
• Primary Examiner(s): Epps; Georgia Y
• Assistant Examiner(s): Owens; Danell L
• Application Number:
  US11/667,111
• Publication Number:
  US 20080036921A1
• Time in Patent Office: 1,894 Days
• Field of Search: 372/6, 372 69- 72, 250/227.18, 348/756, 353/31, 385/32
• US Class Current: 353/31
• 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 of a fiber laser is disposed so as to draw a circulating orbit of more than one circulation along the inner wall of the projector housing. Further, an FBG which is part of the fiber laser is fixed so that its shape is not changed. Furthermore, a pump LD part of the fiber laser is disposed apart from the SHG element. As a result, the video projector can be miniaturized, and the portability and installment of the video projector are facilitated. Further, the output stabilization of the fiber laser can be realized by preventing a 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, said video projector comprising:

a projector housing;

a fiber laser which comprises a pump LD part for emitting a laser beam, and a fiber part, comprising rare-earth doped fiber, for amplifying the emitted laser beam from said pump LD part; and

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

said fiber part is disposed along the inner wall of said projector housing and winds for more than one circulation along said interior wall of said projector housing.

2. The video projector as defined in claim 1, wherein said SHG element and said pump LD part are separated, and said pump LD part is arranged in a state of contacting said inner wall of said 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, further comprising a fiber Bragg grating, at a portion of said fiber part, wherein said fiber Bragg grating is fixed so that the shape of said fiber Bragg grating does not change.

5. The video projector as defined in claim 1, further comprising a control circuit for performing control for suppressing the temperature change of said fiber Bragg grating.

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

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

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

13. The video projector as defined in claim 1, wherein said SHG element and said 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 said projector housing.

14. The video projector as defined in claim 1, further comprising a screen, wherein said SGH element outputs the projection light onto said screen.

9. A video projector for use with a screen and for projecting video onto the screen, said video projector comprising:

a projector housing;

a power cord including a connector part; and

a fiber laser comprising a pump LD part for irradiating a laser beam and a fiber part for amplifying an irradiation beam from said pump LD part, wherein said fiber part is incorporated in said power cord, and said pump LD part is incorporated in said connector part of said power cord, and said pump LD part is arranged external to said projector housing.

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

11. The video projector as defined in claim 9, further comprising an SHG element for converting the wavelength of the emitted light from said fiber laser and outputting a projection light.

12. The video projector as defined in claim 11, further comprising a screen, wherein said SGH element outputs the projection light onto said screen.