Multi-motion micromirror

• US 6,028,689 A
• Filed: 01/24/1997
• Issued: 02/22/2000
• Est. Priority Date: 01/24/1997
• Status: Expired due to Fees

• Current Assignee: United States Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Bright, Victor M., Michalicek, M. Adrian, Comtois, John H.
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Schuberg, Darren E.
• Application Number:
  US08/788,976
• Time in Patent Office: 1,124 Days
• Field of Search: 359/221, 359/223, 359/225, 359/291, 359/295, 359/298, 359/318, 359/872, 359/876, 359/224
• US Class Current: 359/224.1
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

Provided is a movable micromirror assembly wherein a mirror is mounted on, e.g. four flexible support arms, which are mounted in turn on a center support post. The post and arms resiliently support such mirror over, e.g. four address electrodes. The micromirror device is actuated like a parallel-plate capacitor by applying an address potential to the electrodes, which draw a part or all of the mirror toward same, countered by the spring force of the proximate support arms. Motion of the micromirror can be achieved along two axes since the device can be tilted and retracted according to the varying potentials applied to each of the four electrodes and the attractive force applied in turn to various portions of the micromirror in spaced proximity therewith. The support system of the micromirror is positioned beneath the mirror so that no reflective service area is lost to these features. Accordingly individual micromirror assemblies can be placed close to each other, in side by side array, to maximize the active surface area of such array. Thus each such micromirror can be tilted on two axes to scan one or more fields of regard and also can simultaneously be retracted or elevated to a desired depth to remove phase aberrations in the incident image by discreetly lengthening or shortening the optical path of the image reflected therefrom.

Claims

1. A moveable micromirror assembly comprising,

a) a micromirror,

b) a plurality of support flexures supporting said micromirror from underneath, said flexures being mounted on a relatively static support member,

c) means to pull at least a portion of said micromirror against at least one of said flexures to pivot and/or retract said micromirror and

d) means to counter-move said micromirror to dispose same in a desired position.

2. The assembly of claim 1 having a support post beneath said micromirror, said support flexures being mounted on said support post.

3. The assembly of claim 2 wherein said support flexures are flexible support arms which terminate in tips which tips support said micromirror.

4. The assembly of claim 1 having a plurality of address electrodes, at least one of which is positioned below one of said support flexures in spaced proximity therewith.

5. The assembly of claim 4, having means for grounding said micromirror and means to move said micromirror by applying electric potential to at least one of said address electrodes, which pulls said micromirror toward said electrode, against the spring force of at least one of said support flexures.

6. The micromirror of claim 5 having a plurality of corners and at least four support flexures mounted thereto from below and at least four address electrodes spaced beneath said support flexures to pivot and/or retract said micromirror in various desired directions and elevations.

7. A plurality of the micromirror of claim 6 mounted in side-by-side array.

8. A plurality of the micromirror assemblies of claim 5 mounted in side by side array to define a spatial light modulator (SLM).

9. The SLM of claim 8 wherein said micromirrors pivot on two axes to scan a field of regard, which micromirrors can also retract or elevate to discretely lengthen or shorten the optical path of an image reflected therefrom to remove phase aberrations from said image.

10. A plurality of the micromirror of claim 1 mounted in side-by-side array.