Display apparatus including grating light-valve array and interferometric optical system

• US 6,088,102 A
• Filed: 10/31/1997
• Issued: 07/11/2000
• Est. Priority Date: 10/31/1997
• Status: Expired due to Term

• Current Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Original Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Inventors: Manhart, Paul K.
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): LEE, HWA S
• Application Number:
  US08/961,826
• Time in Patent Office: 984 Days
• Field of Search: 356/354, 356/345, 359/577, 359/578
• US Class Current: 356/499
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10

Abstract

Display systems employ a planar grating light-valve (GLV) array as a spatial light-modulator for representing an image to be displayed. The systems rely for image representation on the position of moveable reflective elements of the GLV array, which move through planes parallel to the plane of the array. The moveable elements provide, from an incident phase-constant wavefront, a reflected phase-modulated wavefront representing the image to be displayed. The displayed image is provided by interferometrically combining the phase-modulated wavefront with a reference wavefront also formed, directly or indirectly, from the incident phase-constant wavefront.

Claims

1. A system for displaying an image, comprising:

at least one planar grating light-valve (GLV) array including at least one row of elongated, spaced-apart, parallel-aligned, moveable reflective-members, each of said moveable reflective-members individually moveable with respect to the grating plane, through planes parallel thereto, to an extent corresponding to an element of the image to be displayed; and

imaging interferometer means for displaying an interferogram image of the at-least-one GLV array, the interferogram image, at any instant in time, representing at least a portion of the image to be displayed.

2. The system of claim 1, wherein said imaging interferometer means is arranged according to a Michelson interferometer principle.

3. The system of claim 1, wherein in said GLV array, a row of spaced-apart fixed reflective-members is provided in every row of moveable reflective-members, and said fixed reflective-members are located in a plane parallel to said grating plane, spaced-apart by the same distance as said moveable reflective-members, and laterally arranged such that each thereof is in a position between adjacent ones of said moveable reflective-members;

and wherein said imaging interferometer means is arranged according to a wavefront-shearing interferometer principle.

4. A system for displaying an image, comprising:

a planar grating light-valve (GLV) array including a plurality of rows of elongated, spaced-apart, parallel-aligned, moveable reflective-members, each of said moveable reflective-members individually moveable with respect to a grating plane, through planes parallel to the grating plane, to an extent corresponding to an element of the image to be displayed;

first optical means for providing a first, phase-constant optical-wavefront;

second optical means for forming said first optical-wavefront into a second optical-wavefront spatially phase-modulated by said moveable reflective-members of said GLV array, and a third phase-constant optical-wavefront;

third optical means for forming first and second images of respectively said second and third optical-wavefronts;

and said second and third optical means arranged such that said first and second images interferentially combine to provide the image to be displayed.

5. The system of claim 4, wherein said first and second images are real images projected onto a viewing surface.

6. The system of claim 4, wherein said first and second images are virtual images and are directly viewable by a viewer via said third optical means.

7. The system of claim 4 wherein said second and third optical-wavefronts are provided by dividing said first optical-wavefront into two portions and reflecting one thereof from said GLV array to provide said second optical wavefront, and reflecting the other thereof from a reference mirror to provide said third optical-wavefront.

8. The system of claim 4, wherein in said GLV array, a row of spaced-apart fixed reflective-members is provided in every row of moveable reflective-members, and said fixed reflective-members are located in a plane parallel to said grating plane, spaced-apart by the same distance as said moveable reflective-members, and laterally arranged such that each thereof is in a position between adjacent ones of said moveable reflective-members.

9. The system of claim 8 wherein said second optical means causes said first optical-wavefront to be reflected from said GLV array, then divided into two complex optical-wavefronts each thereof including phase-constant and phase-modulated portions corresponding to respectively said fixed and moveable reflective-members of said GLV array;

and said second optical means causes said two complex optical-wavefronts to propagate axially, laterally displaced one from the other by a distance equal to a whole multiple of a spacing between reflective-members, such that said phase-modulated portions of said two complex wavefronts combine to form the second reflected wavefront, and said phase-constant portions of said two complex wavefronts combine to form the third reflected wavefront.

10. The system of claim 4, wherein said first second and third wavefronts are plane wavefronts.

11. A system for displaying an image, comprising:

a grating light-valve (GLV) array including a plurality rows of elongated, spaced-apart, parallel-aligned moveable reflective-members, each of said moveable reflective-members individually moveable with respect to a grating plane, through planes parallel to the grating plane, to an extent corresponding to an image element to be displayed;

a reference mirror;

first optical means for providing a first, phase-constant optical-wavefront;

second optical means for dividing said first optical-wavefront into first and second portions, said second optical means for forming said first portion of said first portion of said first optical-wavefront into a second optical-wavefront spatially phase-modulated by said moveable reflective-members of said GLV array, and for forming said second portion of said first optical-wavefront, by reflection thereof off said reference mirror, into a third, phase-constant optical-wavefront;

third optical means for forming first and second images of respectively said second and third optical-wavefronts; and

said second and third optical means arranged such that said first and second images interferentially combine to provide the image to be displayed.

12. The system of claim 11, wherein said first and second images are real images projected onto a viewing surface.

13. The system of claim 11, wherein said first and second images are virtual images and are directly viewable by a viewer via said third optical means.

14. A system for displaying an image, comprising:

a grating light-valve (GLV) array including a plurality of rows of elongated, spaced-apart, parallel-aligned, moveable reflective-members, each of said moveable reflective-members individually moveable with respect to a grating plane, through planes parallel to the grating plane, to an extent corresponding to an image element to be displayed, a row of spaced-apart fixed reflective-members being provided in every row of moveable reflective-members, and said fixed reflective-members being located in a plane parallel to said grating plane, spaced-apart by the same distance as said moveable reflective-members, and laterally arranged such that each thereof is in a position between adjacent ones of said moveable reflective-members;

first optical means for providing a first phase-constant optical-wavefront;

second optical means for causing said first optical-wavefront to be reflected from said GLV array then divided into two complex optical-wavefronts, each thereof including phase-constant and phase-modulated portions corresponding to respectively said fixed and moveable reflective-members of said GLV array, and for causing said two complex optical-wavefronts to propagate coaxially, laterally displaced one from the other by a distance equal to a whole multiple of a spacing between reflective-members, such said phase-modulated portions of said two complex optical-wavefronts combine to form a second optical-wavefront spatially modulated by said moveable reflective-members of said GLV array, and said phase-constant portions of said two complex wavefronts combine to form a third, phase-constant optical-wavefront; and

third optical means for forming first and second images of respectively said second and third optical-wavefronts;

and said second and third optical means arranged such that said first and second images interferentially combine to provide the image to be displayed.

15. The system of claim 14, wherein said first and second images are real images projected onto a viewing surface.

16. The system of claim 14, wherein said first and second images are virtual images and are directly viewable by a viewer via said third optical means.

17. A system for displaying a poychromatic image, comprising:

first, second, and third, planar, grating light-valve (GLV) arrays, for processing respectively, red, green and blue primary color components of the image to be displayed, each of said GLV arrays including a plurality rows of elongated, spaced-apart, parallel-aligned, moveable reflective-members, each of said moveable reflective-members individually moveable with respect to a grating plane, through planes parallel to the grating plane to an extent corresponding to an image element to be displayed;

a reference mirror;

a source of polychromatic light including wavelengths representative of said red, green, and blue components of the image to be displayed;

first optical means for providing from said source of polychromatic light a first, phase-constant, optical-wavefront, said first optical-wavefront including said red, green, and blue color components;

second optical means for forming a first portion of said first optical-wavefront into red, green, and blue, second optical-wavefronts spatially phase-modulated by said moveable reflective-members of respectively said first, second, and third GLV arrays, and for reflecting a second portion of said first optical-wavefront off said reference mirror to form a third phase-constant optical-wavefront;

third optical means for forming first, second, third, and fourth images of respectively said red, green and blue second optical wavefronts and said third optical-wavefront; and

said second and third optical means arranged such that said first, second, third, and fourth images interferentially combine to provide the polychromatic image to be displayed.

18. The system of claim 17, wherein said first and second images are real images projected onto a viewing surface.

19. The system of claim 17, wherein said first and second images are virtual images and are directly viewable by a viewer via said third optical means.

20. The system of claim 17, wherein said polychromatic light source includes separate red, green, and blue monochromatic light sources the light output of which is combined by an arrangement of dichroic filters to provide polychromatic light.

21. A system for displaying a polychromatic image, comprising:

first second and third grating light-valve (GLV) arrays for processing respectively, red, green and blue primary color components of the image to be displayed, each of said GLV arrays including a plurality of rows of elongated, spaced-apart, parallel-aligned, moveable reflective-members, each of said moveable reflective-members individually moveable with respect to a grating plane, through planes parallel to the grating plane, to an extent corresponding to an image element to be displayed, a row of spaced-apart fixed reflective-members being provided in every row of moveable reflective-members, and said fixed reflective-members being located in a plane parallel to said grating plane, spaced-apart by the same distance as said moveable reflective-members, and laterally arranged such that each thereof is in a position between adjacent ones of said moveable reflective-members;

a source of polychromatic light including wavelengths representative of said red, green, and blue components of the image to be displayed;

first optical means for providing from said source of polychromatic light a first, phase-constant, polychromatic optical-wavefront, said first optical-wavefront including said red, green, and blue color components;

second optical means for dividing said first polychromatic optical-wavefront into separate red, green, and blue, first optical-wavefronts, for causing said red green, and blue first optical-wavefronts to be reflected from respectively said first second and third GLV arrays, for causing each of said reflected red, green, and blue first optical-wavefronts to be divided into a pair of complex optical-wavefronts each thereof including phase-constant and phase-modulated portions corresponding to respectively said fixed and moveable reflective-members of said GLV array, and for causing the pair of complex optical-wavefronts to propagate coaxially, laterally displaced one from the other by a distance equal to a whole multiple of a spacing between reflective-members, such that phase-modulated portions of red, green, and blue complex optical-wavefront pairs combine to form respectively red, green and blue second optical-wavefronts spatially modulated by said moveable reflective-members of respectively said first second, and third GLV arrays, and the phase-constant portions of the red, green, and blue complex optical-wavefront pairs combine to form respectively red, green, and blue third, phase-constant optical-wavefronts;

third optical means for forming first, second third, fourth, fifth, and sixth images of respectively said red, green, and blue second optical-wavefronts, and said red, green and blue third optical-wavefronts; and

said second and third optical means arranged such that said first, second third, fourth, fifth, and sixth images interferentially combine to provide the polychromatic image to be displayed.

22. The system of claim 21, wherein said first and second images are real images projected onto a viewing surface.

23. The system of claim 21, wherein said first and second images are virtual images and are directly viewable by a viewer via said third optical means.

24. The system of claim 21, wherein said polychromatic light source includes separate red, green, and blue monochromatic light sources light sources, the light output which is combined by an arrangement of optical filters to provide polychromatic light.

25. A system for displaying an image, comprising:

a grating light-valve (GLV) array including a plurality of rows of elongated, spaced-apart, parallel-aligned, moveable reflective-members, each of said moveable reflective-members individually moveable with respect to a grating plane, through planes parallel to the grating plane, to an extent corresponding to an image element to be displayed, a row of spaced-apart fixed reflective-members being provided in every row of moveable reflective-members, and said fixed reflective-members being located in a plane parallel to said grating plane, spaced-apart by the same distance as said moveable reflective-members, and laterally arranged such that each thereof is in a position between adjacent ones of said moveable reflective-members;

first optical means for providing a first phase-constant optical-wavefront;

second optical means for causing said first optical-wavefront to be reflected from said GLV array then divided into second and third optical-wavefronts, each thereof including phase-constant and phase-modulated portions corresponding to respectively said fixed and moveable reflective-members of said GLV array, and for causing said first and second optical-wavefronts to propagate coaxially, laterally displaced one from the other by a distance equal to a whole multiple of a spacing between reflective-members; and

third optical means for forming first and second images of respectively said second and third optical-wavefronts;

and said second and third optical means arranged such that said first and second images interferentially combine to provide the image to be displayed.

26. The system of claim 25, wherein said first and second images are real images projected onto a viewing surface.

27. The system of claim 25, wherein said first and second images are virtual images and are directly viewable by a viewer via said third optical means.

28. A system for displaying an image to viewer, comprising:

at least one planar grating light-valve (GLV) array including a row of elongated, spaced-apart, parallel-aligned, moveable reflective-members, each of said moveable reflective-members individually moveable with respect to the grating plane, through planes parallel thereto, to an extent corresponding to an element of the image to be displayed; and

wherein the displayed image is formed by sweeping a sequence of interferogram images of the GLV array through the field of view of the viewer.

29. The system of claim 28, wherein said inteferogram images are a real images projected onto a viewing surface.

30. The system of claim 28, wherein said inteferogram images are virtual images viewed by the viewer via optical means included in the system for forming said interferogram images.

31. A system for displaying a two-dimensional image, the two-dimensional image including a plurality of lines of image elements, the system comprising:

a grating light-valve (GLV) array including a row of elongated, spaced-apart, parallel-aligned, moveable reflective-members, each of said moveable reflective-members individually moveable with respect to a grating plane, through planes parallel to the grating plane, to an extent corresponding to an element of a line of the image to be displayed;

first optical means for providing a first, phase-constant optical-wavefront;

second optical means for forming said first optical-wavefront into a second optical-wavefront spatially phase-modulated by said moveable reflective-members of said GLV array, and a third phase-constant optical-wavefront;

third optical means for forming first and second images of respectively said second and third optical-wavefronts;

said second and third optical means arranged such that said first and second images interferentially combine to provide an image line of the image to be displayed;

electronic means for operating said moveable elements such that said image line sequentially represents all lines of the image to be displayed; and

scanning means, cooperative with said third optical means and said electronic means, for moving said image line transversely through the field view of a viewer such that said moving image line appears to the viewer as a the two dimensional image.

32. The system of claim 31, wherein said first and second images are real images projected onto a viewing surface viewable by the viewer.

33. The system of claim 32, wherein said first and second images are virtual images and are directly viewable by the viewer via said third optical means.