High speed deformable mirror light valve

• US 6,147,789 A
• Filed: 05/04/1998
• Issued: 11/14/2000
• Est. Priority Date: 05/04/1998
• Status: Expired due to Fees

• Current Assignee: Creo Products Incorporated
• Original Assignee: Creo Products Incorporated
• Inventors: Gelbart, Daniel
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Juba, Jr., John
• Application Number:
  US09/072,753
• Time in Patent Office: 925 Days
• Field of Search: 359/233, 359/224, 359/291, 359/295, 359/846, 359/847, 359/850, 359/852, 359/855, 359/292, 359/230, 359/231, 359/237, 359/238, 359/290, 359/319, 359/900, 348/755, 348/771, 345/31, 345/85, 345/108, 347/135, 347/136, 347/239, 347/255
• US Class Current: 359/231
• CPC Class Codes: B41J 2/465 using masks, e.g. light-switching masks
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/90 Methods

Abstract

A deformable mirror light valve comprised of an array of silicon nitride ribbons, metalized to reflect light. Each ribbon is electrostatically deformed to form a cylindrical mirror. Each deformable ribbon modulates the light of one pixel by focusing the reflected light through a slit. An alternative embodiment focuses the light onto a stop. The ribbon structure has a fast response time combined with high contrast.

Claims

1. A light valve comprising:

a plurality of individually addressable and micro-machined ribbons of silicon nitride each forming an energizable capacitor which may be selectively deformed into an approximately cylindrical form;

a mirror surface formed on each silicon nitride ribbon, said mirror surface having a focus which changes in accordance with the deformation of said eneraizable capacitor;

a target surface remote from the mirror surfaces; and

an aperture, positioned between the mirror surfaces and the target surface, for converting the change in focus of each mirror surface into a light intensity change; and

a source of electrical energy coupled to and configured to selectively energize and deform each capacitor.

2. The apparatus of claim 1 further including a lens located between said aperture and said target surface.

3. The apparatus of claim 1 wherein said target surface is a light sensitive surface.

4. A method of forming a high speed deformable mirror light valve comprising the acts of:

(1) forming a ribbon including an electrically conductive surface on a silicon nitride surface, the ribbon having first and second ends;

(2) supporting the ribbon at its first and second ends;

(3) deforming the ribbon into a mirror having an approximately cylindrical shape by applying an electrical signal to the conductive surface;

(4) providing a source of light reflected by said mirror;

(5) placing an element including transparent and nontransparent areas in a manner that converts said deformation of said mirror into changes of intensity of said reflected light at approximately the focal point of the mirror.

5. The method as setforth in claim 4 further including the act of depositing a reflective coating on said conductive surface.

6. The method as set forth in claim 4 wherein the act of forming the ribbon includes the act of micro-machining the ribbon.

7. The method of deforming the ribbon as in claim 6 includes deforming the ribbon into the micro-machined silicon nitride surface.

8. The method of claim 4 wherein the act of placing said transparent and nontransparent areas at approximately the focal point of the mirror includes the act of forming an aperture of said transparent and nontransparent areas and placing said aperture at approximately the focal point of the mirror.

9. The invention in accordance with claim 8 wherein said aperture is a linear aperture.