ELECTROSTATICALLY DEFLECTABLE LIGHT VALVES FOR PROJECTION DISPLAYS

• US 3,746,911 A
• Filed: 04/13/1971
• Issued: 07/17/1973
• Est. Priority Date: 04/13/1971
• Status: Expired due to Term

• Current Assignee: Harvey C. Nathanson, John R. Davis, Jr.
• Original Assignee: Harvey C. Nathanson, John R. Davis, Jr.
• Inventors: Nathanson, Harvey C., Davis, John R. Jr.
• Primary Examiner(s): Padgett, Benjamin R.
• Assistant Examiner(s): Potenza, J. M.
• Application Number:
  US05/133,608
• Time in Patent Office: 826 Days
• Field of Search: 178/5.4BD,7.5D 315/21 313/91
• US Class Current: 348/771
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: H01J 29/12 acting as light valves by shutter operation, e.g. for eidophor
• CPC Class Codes: H04N 5/7425 the modulator being a dielectric deformable layer controlled by an electron beam, e.g. eidophor projector

Abstract

An electrostatically deflectable light valve for use in large area projection display. The system utilizes an array of electrostatically deflectable reflective elements lying in a plane which provides modulation of a light source directed thereon so as to spatially modulate and produce a display of brightness analogous to the amplitude of the deformation of the reflective elements. The elements of the array are comprised of a centrally located post supporting the reflective element. A common ground plane electrode is provided beneath the reflective elements and is capacitively associated therewith. This ground plane electrode in the cathode ray tube embodiment intercepts the electrons that are not intercepted by the reflective elements. The materials and the processes used in the fabrication particularly adapt themselves to the fabrication of large area devices having a resolution capability similar to that of television.

Claims

1. An electrostatically deflectable light valve system comprising an array of spaced apart deformable light reflective elements, each of said reflective elements supported by a spacer post member extending from a base member, said base member providing a potential electrode positioned near the base of said spacer post member said spacer post member having substantially less cross section than said light reflective element and located entirely beneath said light reflective elements.

2. The system set forth in claim 1 in which said base member is selected from materials of the group consisting of silicon, quartz, glass, sapphire and spinel.

3. The system set forth in claim 1 in which the spacer post members are selected from a group of materials consisting of silicon, aluminum, silver, nickel and silicon dioxide.

4. An electrostatically deflectable light valve system comprising an array of spaced apart deformable light reflective elements, each of said refelctive elements supported by a spacer post member extending from the base member, said base member providing a potential electrode positioned near the base of said spacer post member, said light reflective elements selected from materials of the group consisting of aluminum, platinum, titanium, gold and cadmium.

5. An electrostatically deflectable light valve system comprising an array of spaced apart deformable light reflective elements, each of said reflective elements supported by a spacer post member extending from the base member, said base member providing a potential electrode positioned near the base of said spacer post member, said light reflective elements comprising a substrate of silicon dioxide and a reflective coating of a metal.

6. An electrostatically deflectable light valve system comprising an array of spaced apart deformable light reflective elements, each of said reflective elements supported by a spacer post member extending from the base member, said base member providing a potential electrode positioned near the base of said spacer post member, said base member selected from materials of the group consisting of sapphire and spinel, and said spacer post is of silicon material.

7. An electrostatically deflectable light valve system comprising an array of spaced apart deformable light reflective elements, each of said reflective elements supported by a spacer post member extending from the base member, said base member proViding a potential electrode positioned near the base of said spacer post member, said spacer post member has a substantially less cross section than said light reflective element and is centrally located with respect to said light reflective element.

8. The system set forth in claim 1 in which said reflective elements are rectangular and said post members are rectangular in cross section.

9. An electrostatically deflectable light valve system comprising an array of spaced apart deformable light reflective elements, each of said reflective elements supported by a spacer post member extending from the base member, said base member providing a potential electrode positioned near the base of said spacer post member, said light reflective elements and said post members are circular in cross section.

10. An electrostatically deflectable light valve system comprising an array of spaced apart deformable light reflective elements, each of said reflective elements supported by a spacer post member extending from the base member, said base member providing a potential electrode positioned near the base of said spacer post member, said potential electrode extending beneath said light reflective elements to provide a non-uniform distributed coating beneath said reflective element.

11. An electrostatically deflectable light valve system comprising an evacuated envelope having an electron gun and a light valve target structure, said light valve target structure supported upon a light transmissive input window, said light valve target structure comprising an array of spaced deformable light reflective elements lying in a single plane and capable of reflection of light transmitted through said input window, each of said reflective elements supported by a centrally located post member secured to the undersurface of said reflective element and to said input window, a potential electrode common to all of said array of reflective elements positioned on said input window at the base of said post members, said potential electrode operating at a fixed potential, a means for scanning an electron gun over said reflective elements to deposit a charge thereon to effect deformation of said reflective elements in an amount determined by the difference of potential of said reflective elements and the potential of said potential electrode, means for directing light through said input window onto said reflective elements and means for displaying an image representative of the reflective light from said reflective elements corresponding to the deformation thereof.

12. The light valve system set forth in claim 11 in which said potential electrode is provided as a coating on the exposed areas of said substrate to said electron beam and also extending beneath the reflective elements to provide a non-uniform coating beneath the reflective distributed element.

13. The light valve system set forth in claim 12 in which said non-uniform distributed coating beneath said reflective element provides symmetrical deformation about a plane perpendicular to the reflective element and passing through the center of the post member.

14. An electrostatically deflectable light valve system comprising an evacuated envelope having an electron gun and a light valve target structure, said light valve target structure comprising an array of spaced deformable light reflective elements lying in a single plane and capable of reflection of light, said reflective elements supported by a centrally located post member secured to the under-surface of said reflective elements and to said input window, a potential electrode common to all of said array of reflective elements and positioned on said input window at the base of said post members, said potential electrode operating at a fixed potential, means for scanning an electron beam generated by said electron gun over said reflective elements, said centrally located post member including photosensitive means responsive to input radiations to modify the resistance thereOf and thereby change the charge on said reflective elements and causing deformation in response to said input radiations and means for directing a flooding radiation onto said reflective elements and means for displaying an image of the reflected flooding radiation from said reflective elements corresponding to the deformation of said reflective elements.

15. The light valve system of claim 14 in which said photosensitive means is a P-N junction.