Image display device and adjustment for alignment

• US 20040046944A1
• Filed: 08/13/2003
• Published: 03/11/2004
• Est. Priority Date: 05/10/2000
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Suzuki, Hiroshi, Teramoto, Kohei, Suzuki, Jiro, Shikama, Shinsuke
• Granted Patent: US 6,824,274 B2
• Time in Patent Office: Days
• US Class Current: 353/77
• CPC Class Codes: G02B 13/16 for use in conjunction with image converters or intensifiers , or for use with projectors, e.g. objectives for projection TV
• CPC Class Codes: G02B 13/18 with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration G02B13/002 takes precedence
• CPC Class Codes: G02B 17/002 Arrays of reflective systems
• CPC Class Codes: G02B 17/08 Catadioptric systems used in non-imaging applications G02B19/00
• CPC Class Codes: G02B 17/0852 having a field corrector only
• CPC Class Codes: G02B 17/086 wherein the system is made of a single block of optical material, e.g. solid catadioptric systems
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 27/18 for optical projection, e.g. combination of mirror and condenser and objective photographic, cine and overhead projectors G03B21/00; photographic projection printing G03B27/32; photolithographic projectors G03F7/20; projection television H04N5/74; colour projection television H04N9/31
• CPC Class Codes: G02B 5/09 Multifaceted or polygonal mirrors , e.g. polygonal scanning mirrors; Fresnel mirrors
• CPC Class Codes: G02B 7/181 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
• CPC Class Codes: G02B 7/28 Systems for automatic generation of focusing signals
• CPC Class Codes: G03B 21/10 Projectors with built-in or built-on screen
• CPC Class Codes: G03B 21/16 Cooling; Preventing overheating
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066
• CPC Class Codes: G03B 21/53 Means for automatic focusing, e.g. to compensate thermal effects
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/12 Picture reproducers H04N9/11 takes precedence
• CPC Class Codes: H04N 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: H04N 9/3147 Multi-projection systems displays in general H04N9/12; video walls G06F3/1446, G09G2300/026
• CPC Class Codes: H04N 9/317 : Convergence or focusing systems electronic adjustment of convergence H04N9/3185; convergence or focusing arrangements for cathode ray tubes H04N9/28; means for automatic focusing of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/53
• CPC Class Codes: H04N 9/3194 : including sensor feedback

Abstract

A refracting optical lens 15 is provided to project light from transmitting means onto a convex mirror 16 to correct for pincushion distortion of the convex mirror 16.

Claims

1. An image display device provided with transmitting means for providing image information to illumination light and for transmitting said light as an optical image signal and display means for receiving said optical image signal and for displaying an image based on said image information, said image display device comprising:

projecting optical means composed of a reflecting part having a reflecting surface for reflecting said optical image signal, and a refracting optical part having a refracting surface for projecting said optical image signal onto said reflecting part;

wherein said display means receives said optical image signal through said projecting optical means;

at least one of said reflecting surface and said refracting surface is aspherical; and

said projecting optical means is provided with path-bending means for reflecting said optical image signal from said refracting optical part to said reflecting part, the optical axis of said refracting optical part being bent at an appropriate angle in a horizontal plane containing the optical axis of said reflecting part.

2. The image display device according to claim 1, wherein said reflecting part or refracting optical part reflects or refracts said optical image signal by said reflecting or refracting surface except around the optical axis of said reflecting or refracting part.

3. The image display device according to claim 1, wherein said projecting optical means is provided with path-bending arrangement for reflecting said optical image signal from a first lens element to a second lens element.

4. The image display device according to claim 1, wherein said refracting optical part has at least one lens formed of synthetic resin.

5. The image display device according to claim 1, wherein said refracting optical part and said reflecting part are rotationally symmetric about an optical axis made common to them.

6. The image display device according to claim 1, wherein the angle of bending the optical axis of said refracting optical part is set such that said refracting optical part is as close to a path from said path-bending arrangement to said reflecting part as possible without intercepting said optical part.

7. The image display device according to claim 3, wherein the angle of bending the optical axis of said first lens means is set such that said first lens means is as close to a path from said path-bending arrangement to said second lens means as possible without intercepting said optical path.

8. The image display device according to claim 3, wherein the longest distance from said refracting optical part to a reflecting part placement plane is chosen within a range smaller than a thickness limiting value.

9. The image display device according to claim 8, wherein the longer one of the longest distance from a reflecting part placement plane to said path-bending arrangement and the longest distance from said reflecting part placement plane to said refracting optical part is equal to a thickness limiting value.

10. The image display device according to claim 6, wherein the longest distance from a reflecting part placement plane to said path-bending means and the longest distance from said reflecting part placement plane to said refracting optical part are equal to each other.

11. The image display device according to claim 6, wherein said refracting optical part has a shape obtained by removing a non-transmitting portion that does not transmit said optical image signal.

12. The image display device according to claim 1, wherein said projecting optical arrangement has poor optical performance in an unused area around its optical axis but has high image formation performance in an area to be used other than that around said optical axis.

13. The image display device according to claim 12, wherein said projecting optical arrangement is adapted so that an image-forming position at the center of said optical axis and an image-forming position around said optical axis are not in the same plane.

14. The image display device according to claim 12, wherein said projecting optical means allows distortion in the vicinity of the center of said optical axis to increase formation performance of said area to be used.

15. The image display device according to claim 12, wherein said projecting optical means limits the image or degradation of the optical performance to the image of the field angle related only to the base of a screen.

16. The image display device according to claim 14, wherein a plane mirror for reflecting said light from said projecting optical means to said display means has a surface configuration that corrects for distortion of said projecting optical means.

17. The image display device according to claim 1, wherein said refracting optical part has a construction in which an exit pupil of light emitted toward the central area of said reflecting part around the optical axis thereof and an exit pupil of light emitted toward the peripheral area of said reflecting part are spaced apart to thereby adjust the position and angle of incidence of said emitted light toward said reflecting part.

18. An image display device provided with transmitting means for providing image information to illumination light and for transmitting said light as an optical image signal and display means for receiving said optical image signal and for displaying an image based on said image information, said image display device comprising:

projecting optical means composed of a reflecting part having a reflecting surface for reflecting said optical image signal, and a refracting optical part having a refracting surface for projecting said optical image signal onto said reflecting part;

wherein said display means receives said optical image signal through said projecting optical means;

at least one of said reflecting surface and said refracting surface is aspherical; and

said reflecting part has a shape obtained by removing a non-reflecting portion that does not reflect said optical image signal to said display means.

19. The image display device according to claim 18, wherein said projecting optical means is provided with path-bending arrangement for reflecting said optical image signal from a first lens element to a second lens element.

20. The image display device according to claim 18, wherein said refracting optical part has at least one lens formed of synthetic resin.

21. The image display device according to claim 18, wherein said refracting optical part and said reflecting part are rotationally symmetric about an optical axis made common to them.

22. The image display device according to claim 18, wherein said projecting optical arrangement has poor optical performance in an unused area around its optical axis but has high image formation performance in an area to be used other than that around said optical axis.

23. The image display device according to claim 18, wherein said refracting optical part has a construction in which an exit pupil of light emitted toward the central area of said reflecting part around the optical axis thereof and an exit pupil of light emitted toward the peripheral area of said reflecting part are spaced apart to thereby adjust the position and angle of incidence of said emitted light toward said reflecting part.