Resonant mirror and method of manufacture

• US 5,233,456 A
• Filed: 12/20/1991
• Issued: 08/03/1993
• Est. Priority Date: 12/20/1991
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Nelson, William E.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US07/811,407
• Time in Patent Office: 592 Days
• Field of Search: 359/212, 359/213, 359/214, 359/221, 359/223, 359/224, 359/225, 359/847, 359/848, 359/850, 359/851, 359/872, 359/846
• US Class Current: 359/214.1
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A resonant mirror is disclosed which comprises a deflectable mirror generally planar with the stop surface of a substrate. The mirror is suspended adjacent the top surface by at least two supporting elements. At least one supporting element is displaced from an edge of the mirror. The supporting elements, being collinear, define an axis of rotation about which the mirror may oscillate to steer incident light through an angle.

Claims

1. A resonant mirror comprising:

a substrate having a top surface;

a deflectable mirror element generally planar with the top surface and defining first and second ends; and

at least two supporting elements for suspending the mirror element adjacent the top surface, the supporting elements defining an axis of rotation, at least one supporting element being a supporting member which is displaced from both said first and second ends of the mirror element.

2. The resonant mirror of claim 1 further comprising at least one electrode displaced outwardly in a first direction from the axis of rotation for periodically causing the mirror element to rotate about the axis of rotation when the first electrode is electrically coupled to a first voltage source and the mirror element is electrically coupled to a second voltage source.

3. The resonant mirror of claim 2 further comprising a stop at the same electrical potential as the mirror element, the stop being displaced outwardly from the first electrode whereby said mirror element lands on the stop prior to landing on the first electrode.

4. The resonant mirror of claim 2 further comprising a second electrode displaced outwardly from the axis of rotation in a second direction, the second direction being generally opposite to the first direction, the second electrode for periodically causing the mirror element to rotate about the axis of rotation when the second electrode is coupled to a third voltage source.

5. The resonant mirror of claim 1 wherein said at least two supporting elements are three or more supporting elements.

6. The resonant mirror of claim 5 wherein said three or more supporting elements include two supporting elements, each being connected to said first and second ends.

7. The resonant mirror of claim 1 wherein every one of said at least two supporting elements is displaced from both said first and second ends of the mirror.

8. A method of manufacturing a resonant mirror on a substrate comprising the steps of:

fabricating at least one support pad on a substrate;

depositing a spacer layer over the pad;

exposing the support pad;

depositing a hinge layer on the spacer layer and the exposed pad;

coating portions of the hinge layer with an etch stop;

depositing a mirror layer on the coated hinge layer;

selectively etching the mirror and hinge layers to create a mirror having at least two supporting elements, at least one of the supporting elements being displaced from an edge of the mirror; and

removing the spacer layer.

9. The method of claim 8 wherein the step of depositing a spacer layer further comprises the step of depositing a layer of photomask.

10. The method of claim 9 wherein the steps of depositing a hinge layer and depositing a mirror layer further comprise the steps of:

depositing a hinge layer of Ti;

Si;

Al; and

depositing a mirror layer of Ti;

Si;

Al.

11. The method of claim 8 wherein the steps of depositing a hinge layer and depositing a mirror layer further comprise the steps of:

depositing a hinge layer of Ti;

Si;

Al; and

depositing a mirror layer of Ti;

Si;

Al.

12. A method of manufacturing a resonant mirror on a substrate comprising the steps of

forming a rotatably mirror having first and second ends;

forming at least tow supporting elements for supporting the mirror adjacent the substrate, the supporting elements forming an axis of rotation, at least one of the supporting elements being a supporting member which is displaced from both said first and second ends of the mirror.

13. The method of claim 12 further comprising the steps of:

depositing a spacer material on the substrate; and

removing the spacer layer after forming the rotatable mirror.

14. The method of claim 13 wherein the two forming steps further comprise the steps of:

forming at least one support post of Ti;

Si;

Al; and

forming the rotatable mirror of Ti;

Si;

Al.

15. The method of claim 12 wherein the two forming steps further comprise the steps of:

forming at least one support post of Ti;

Si;

Al; and

forming the rotatably mirror of Ti;

Si;

Al.

16. The method of claim 12 wherein said step of forming at least two supporting elements comprises the step of forming every one of said at least two supporting elements displaced from both said first and second ends of said mirror.

17. The method of claim 12 wherein said step of forming at least two supporting elements comprises forming three or more supporting elements.

18. The method of claim 17 wherein said step of forming three or more supporting elements comprises the step of forming two of said supporting elements, each being connected to said first and second ends.

19. A resonant mirror comprising:

a substrate having a top surface;

a deflectable mirror element generally planar with the top surface; and

at least tow supporting members for suspending the mirror element adjacent the top surface, the supporting members defining an axis of rotation and being displaced from an edge of the mirror element.

20. The resonant mirror of claim 19 further comprising at least one electrode displaced outwardly in a first direction from the axis of rotation for periodically causing the mirror to rotate about the axis of rotation when the first electrode is electrically coupled to a first voltage source and the mirror is electrically coupled to a second voltage source.