Projection type display apparatus

• US 20070252956A1
• Filed: 04/24/2007
• Published: 11/01/2007
• Est. Priority Date: 04/25/2006
• Status: Abandoned Application

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Sasagawa, Tomohiro, Kuwata, Muneharu
• Application Number:
  US11/790,256
• Publication Number:
  US 20070252956A1
• Time in Patent Office: Days
• US Class Current: 353/69
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066
• CPC Class Codes: G03B 21/62 Translucent screens

Abstract

In a projection type display apparatus includes an illumination device (including a light source), a light modulation element, a projection optical system that projects a modulated light from the light modulation element, and a screen onto which a projected light is projected. The projection optical system includes a refraction type optical system that refracts the modulated light from the light modulation element, and a hologram element disposed on a position remote from the screen and shifted in a direction parallel to the screen from a center of the screen. The hologram element projects the modulated light having passed through the refraction type optical system onto the screen so that a light ray of the center of the modulated light is inclined with respect to a normal line of the screen.

Claims

1. A projection type display apparatus comprising:

an illumination device including a light source;

a light modulation element to which image signal is inputted and which modulates a light from said illumination device according to said image signal;

a projection optical system which projects a modulated light from said light modulation element in an enlarged manner, and

a screen onto which a projected light from said projection optical system is projected so that an image is displayed thereon,

wherein said projection optical system comprises;

a refraction type optical system which refracts said modulated light from said light modulation element, and

a hologram element disposed on a position remote from said screen and shifted in a direction parallel to said screen from a center of said screen, said hologram element projecting said modulated light having passed through said refraction type optical system onto said screen so that a light ray of the center of said modulated light is inclined with respect to a normal line of said screen.

2. The projection type display apparatus according to claim 1, wherein said light source of said illumination device includes a laser light source.

3. The projection type display apparatus according to claim 1, wherein said hologram element has a planar shape.

4. The projection type display apparatus according to claim 1, wherein said hologram element is disposed parallel to said screen.

5. The projection type display apparatus according to claim 1, wherein said hologram element is a light-reflection type hologram element.

6. The projection type display apparatus according to claim 1, wherein said hologram element is a light-transmission type hologram element.

7. The projection type display apparatus according to claim 1, wherein a planar reflection surface is disposed on a light path from said refraction type optical system to said hologram element,

wherein said illumination device, said light modulation element and said refraction type optical system are disposed on the same side as said hologram element with respect to a surface including said screen and perpendicular to a normal line of said screen.

8. The projection type display apparatus according to claim 1, wherein said screen is a light-transmission type screen.