Image projector

• US 7,866,831 B2
• Filed: 03/13/2006
• Issued: 01/11/2011
• Est. Priority Date: 03/16/2005
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Hori, Yoshikazu, Kasazumi, Ken'ichi
• Primary Examiner(s): Epps; Georgia Y
• Assistant Examiner(s): CHOWDHURY, SULTAN U.
• Application Number:
  US11/886,155
• Publication Number:
  US 20080198334A1
• Time in Patent Office: 1,765 Days
• Field of Search: 353/31, 353/98, 353/46, 353/48, 353/49, 353/50, 353/119, 359/707, 359/622, 359/634, 359/196.1, 359/197.1, 359/198.1, 359/199.1, 359/199.4, 359/838, 359/599, 359/600, 359/601, 372/108, 372/15, 372/24, 349/112, 349/113
• US Class Current: 353/98
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G03B 21/10 Projectors with built-in or built-on screen
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066

Abstract

An image projector realizing image projection with high image quality by reducing speckle noise. An image projector comprising a coherent light source, a collimation lens for transforming coherent light emitted from the coherent light source into coherent parallel light, and a projection optical system for projecting coherent parallel light is further provided with a reflection element for reflecting the coherent parallel light and capable of oscillating in parallel with the direction normal to the reflection plane, and a reflection element drive means for causing oscillatory motion of the reflection element.

Claims

1. An image projector, comprising:

a coherent light source;

a collimator lens that collimates coherent light from said coherent light source to form collimated coherent light;

a projector optical system that projects the collimated coherent light;

a reflector element that reflects the collimated coherent light and is capable of vibrating in parallel with a direction normal to a reflector surface of said reflector element; and

a reflector element driver unit that drives said reflector element in vibrating motion;

wherein said reflector element driver unit drives said reflector element in reciprocatory vibrating motion in a normal direction of a principal surface of said reflector element; and

wherein a vibration range of said reflector element is more than or equal to square root of 2 times of a maximum period of concavity and convexity profile which is formed on a surface of said first diffuser element and used for light diffusion.

2. An image projector, comprising:

a coherent light source;

a collimator lens that collimates coherent light from said coherent light source to form collimated coherent light;

a projector optical system that projects the collimated coherent light;

a reflector element that reflects the collimated coherent light and is capable of vibrating in parallel with a direction normal to a reflector surface of said reflector element;

a reflector element driver unit that drives said reflector element in vibrating motion; and

a first diffuser element that diffuses the collimated coherent light, said first diffuser element being disposed on an optical path of the collimated coherent light between said collimator lens and said reflector element;

wherein a diffusion angle of said first diffuser element is less than or equal to an angle arcsin of NA, the NA being a numerical aperture of a lens unit of said projector optical system.