Image display system

• US 7,237,908 B2
• Filed: 11/02/2006
• Issued: 07/03/2007
• Est. Priority Date: 11/09/2001
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Suzuki, Hiroshi, Teramoto, Kohei, Shikama, Shinsuke, Wadaka, Shuso
• Primary Examiner(s): KOVAL, MELISSA J
• Application Number:
  US11/555,998
• Publication Number:
  US 20070058228A1
• Time in Patent Office: 243 Days
• Field of Search: 353/70, 353/76, 353/77, 353/78, 353/79, 353/99, 359/456, 359/457, 359/460
• US Class Current: 353/77
• CPC Class Codes: G03B 21/10 Projectors with built-in or built-on screen

Abstract

An image display system includes a light valve 14 for providing image information to light converged by a converging lens 13 and for emitting the light, a projective optical system 20 including a refractive optical lens 21 for projecting the light from the light valve 14 and a convex mirror 22 for reflecting the light from the refractive optical lens 21 by using a reflecting surface thereof having negative power and for enlarging and projecting the reflected light, and a display 30 for receiving the light from the projective optical system 20 by way of a receiving surface 30A, wherein the light valve is placed away from an optical axis 23 of the projective optical system 20 and between a front surface of the display 30 and a rear surface of the projective optical system 20.

Claims

1. An image display system comprising:

a transmission system for providing image information to illuminating light and for transmitting the illuminating light as an optical image signal;

a projective optical system provided with a refractive optical unit for projecting said optical image signal transmitted thereto from said transmission system and a reflective optical unit for reflecting said optical image signal projected by said refractive optical unit; and

a display for receiving said optical image signal by way of said projective optical system and for displaying an image based on said image information,

wherein said transmission system is placed below a horizontal plane including an optical axis of said projective optical system and is also placed between a front surface of said display and a rear surface of said projective optical system, and said display is placed above the horizontal plane including the optical axis of said projective optical system, and

wherein said display is so placed as to be substantially perpendicular to the optical axis of said projective optical system.

2. The image display system according to claim 1, wherein the front surface of said display is defined based on said image display system, and the rear surface of the projective optical system is defined based on said image display system.

3. The image display system according to claim 1, wherein both an image exit surface of light valve means, which constitutes said transmission system, and said display are so arranged that they are substantially parallel to each other.

4. The image display system according to claim 1, wherein said projective optical system is provided with at least one optical path bending element that is disposed on an optical path extending from said transmission system to said display.

5. The image display system according to claim 4, wherein said optical path bending element is so placed that a normal vector that is oriented in a direction of a normal to a reflecting surface of said optical path bending element is substantially parallel to a plane including the optical axis of said projective optical system and being parallel to a lower side of an image display screen of said display.

6. The image display system according to claim 1, wherein said projective optical system comprises at least one optical path bending element disposed on an optical path extending from said transmission system to said display, for bending the optical path in a substantially-horizontal plane.

7. The image display system according to claim 1, wherein said display comprises a Fresnel lens having at least one pitch at which a totally reflective prism portion is formed.

8. The image display system according to claim 1, wherein said display comprises a Fresnel lens having at least one pitch at which two or more different-type prism portions are formed.

9. The image display system according to claim 8, wherein when a refractive prism portion is formed in said Fresnel lens, said display is provided with a thin-film photoabsorptive layer disposed on an ineffective surface of said refractive prism portion, for absorbing light.

10. The image display system according to claim 8, wherein said display further comprises a stray light absorptive plate including a plurality of light transmission layers for allowing light to pass there through and a plurality of photoabsorptive layers for absorbing incident light, each of which is sandwiched between two of the plurality of light transmission layers so that said plurality of photoabsorptive layers are arranged in substantially parallel with an optical axis of said Fresnel lens, said stray light absorptive plate being disposed on an exit surface of said Fresnel lens.

11. The image display system according to claim 10, wherein said stray light absorptive plate of said display is integrally formed on the exit surface of said Fresnel lens.

12. The image display system according to claim 10, wherein in said stray light absorptive plate of said display, the plurality of light transmission layers and the plurality of photoabsorptive layers are so laminated that they are concentrically arranged with respect to the optical axis of said Fresnel lens.

13. The image display system according to claim 10, wherein in said stray light absorptive plate of said display, the plurality of light transmission layers and the plurality of photoabsorptive layers are so laminated that they are arranged in substantially parallel with a certain direction.

14. The image display system according to claim 8, wherein said display further comprises a photoabsorptive plate disposed on an exit surface of said Fresnel lens, for absorbing light.

15. The image display system according to claim 1, wherein said display comprises a Fresnel lens in which prism portions are formed in both an entrance surface and an exit surface of said Fresnel lens.