Light valve target comprising electrostatically-repelled micro-mirrors

• US 5,926,309 A
• Filed: 04/29/1998
• Issued: 07/20/1999
• Est. Priority Date: 04/18/1997
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Memsolutions, Inc.
• Inventors: Little, Michael J.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/069,122
• Time in Patent Office: 447 Days
• Field of Search: 359/290, 359/291, 359/293, 359/295, 359/846, 359/223, 359/230, 348/770, 348/771
• US Class Current: 359/293
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: H04N 5/7425 the modulator being a dielectric deformable layer controlled by an electron beam, e.g. eidophor projector
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14

Abstract

A high intensity light modulator includes a micro-mirror light valve target with electrostatically-repelled micro-mirror elements. Each micro-mirror of the target array comprises a base electrode and an overlying micro-mirror element. In operation, charge is deposited upon the micro-mirrors to produce repulsive electrostatic forces that outwardly deflect the micro-mirror elements by an amount proportional to the deposited charge. In one embodiment, an array of micro-mirror light valves is formed directly upon the face plate of a vidicon tube and is addressed using a scanning electron gun.

Claims

1. A light modulator, comprising:

a) a light valve target having a plurality of electrostatically-actuable micro-mirrors, each said micro-mirror including a flexible micro-mirror element that is spaced-apart from an underlying base electrode; and

b) a charge distributor for distributing electrical charge in a predetermined pattern over said target so that predetermined amounts of charge are deposited upon selected micro-mirrors to produce electrostatic repulsive forces that outwardly deflect said micro-mirror elements away from said electrodes in accordance with the amount of charge.

2. A light modulator as defined in claim 1 wherein said charge distributor comprises:

a) an electron gun for delivering charge to said micro-mirrors; and

b) a plurality of electrically conductive paths that join the micro-mirror elements to their respective base electrodes such that charge migrates between said flexible micro-mirror element and said base electrode to produce the repulsive force that outwardly deflects said micro-mirror element.

3. A light modulator as defined in claim 2, wherein each said micro-mirror further comprises an electrically conductive hinge that flexibly joins said micro-mirror element to said base electrode to provide said electrically conductive path.

4. A light modulator as defined in claim 1 wherein said plurality of micro-mirrors is arranged in an array, said charge distributor comprising:

a) a substrate formed with a corresponding array of drive transistors that deliver charge to the respective micro-mirrors; and

b) a plurality of electrically conductive paths that join the micro-mirror elements to their respective base electrodes such that charge migrates between said base electrode and said micro-mirror element to produce the repulsive force that outwardly deflects said micro-mirror element.

5. A light modulator as defined in claim 4, wherein each said micro-mirror further comprises an electrically conductive hinge that flexibly joins said micro-mirror element to said base electrode to provide said electrically conductive path.

6. A light modulator as defined in claim 1, further comprising an optical system for receiving the modulated light beam reflected from said target and generating a visible image therefrom.

7. An electro-optical modulator for reflective image projection comprising, in combination:

a) a plurality of electrostatically-actuable micro-mirrors;

b) each of said micro-mirrors including a micro-mirror element and a base electrode;

c) an electrically conductive path that joins the micro-mirror element to said base electrode such that charge migrates between said micro-mirror element and said base electrode to produce an electrostatically-repulsive force; and

d) said micro-mirror element and said base electrode each comprising electrically-conductive material whereby said micro-mirror element will be outwardly deflected in response to the accumulation of a quantity of charge on both said micro-mirror element and said base electrode that produces said electrostatically-repulsive force.

8. A projection system as defined in claim 7, wherein each said micro-mirror further comprises an electrically conductive hinge that flexibly joins said micro-mirror element to said base electrode and provides said electrically conductive path.

9. A projection system, comprising:

a) a vidicon tube;

b) a target that is formed upon the face plate of said vidicon tube, said target having a plurality of electrostatically-actuable micro-mirrors that are arranged to receive a beam of light that is directed onto said face plate, each said micro-mirror including a micro-mirror element that is spaced-apart from an underlying base electrode; and

c) a scanning electron gun in said vidicon tube for distributing electrical charge in a predetermined pattern over said target so that predetermined amounts of charge are deposited upon selected micro-mirrors to produce electrostatic repulsive forces that outwardly deflect and pivot said micro-mirror elements away from said electrodes thereby modulating the light beam in accordance with the amount of charge and directing the modulated light beam back through said face plate.

10. A projection system as defined in claim 9, further comprising an electrically conductive path that joins the micro-mirror element to said base electrode, said electron gun scanning said target to deposit the charge on the selected micro-mirror element such that the charge migrates to said base electrode to produce the repulsive force that outwardly deflects said micro-mirror element.