Micro-mirror device including dielectrophoretic liquid

• US 6,924,922 B2
• Filed: 10/26/2004
• Issued: 08/02/2005
• Est. Priority Date: 03/12/2003
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Reboa, Paul F.
• Primary Examiner(s): Shafer, Ricky D.
• Application Number:
  US10/976,232
• Publication Number:
  US 20050088767A1
• Time in Patent Office: 280 Days
• Field of Search: 359/224, 359/290, 359/291, 359/295, 359/296, 359/900
• US Class Current: 359/296
• CPC Class Codes: G02B 26/004 based on a displacement or a deformation of a fluid
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G03F 7/70116 Off-axis setting using a programmable means, e.g. liquid crystal display [LCD], digital micromirror device [DMD] or pupil facets
• CPC Class Codes: G03F 7/70891 Temperature
• CPC Class Codes: Y10S 359/90 Methods
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A micro-mirror device includes a substrate having a surface, and a plate spaced from and oriented substantially parallel to the surface of the substrate such that the plate and the surface of the substrate define a cavity therebetween. A dielectrophoretic liquid capable of movement when an electrical signal is applied to the micro-mirror device is disposed in the cavity, and a reflective element is interposed between the surface of the substrate and the plate such that the reflective element is adapted to move between a first position and at least one second position. The dielectrophoretic liquid includes at least one compound selected from the group consisting of siloxanes and silanes substantially free of asymmetrical ether linkages.

Claims

1. A micro-actuator, comprising:

a substrate having a surface;

a plate spaced from and oriented substantially parallel to the surface of the substrate, the plate and the surface of the substrate defining a cavity therebetween;

a dielectrophoretic liquid disposed in the cavity and capable of movement when an electrical signal is applied to the micro-actuator, the dielectrophoretic liquid including at least one compound selected from the group consisting of siloxanes substantially free of asymmetrical ether linkages and silanes substantially free of asymmetrical ether linkages; and

an actuating element interposed between the surface of the substrate and the plate,

wherein the actuating element is adapted to move between a first position and at least one second position.

2. A micro-actuator according to claim 1, wherein the dielectrophoretic liquid has a dielectric constant of less than about 20.

3. A micro-actuator according to claim 1, wherein the dielectrophoretic liquid has a flashpoint greater than about 60 degrees Centigrade.

4. A micro-actuator according to claim 1, wherein the dielectrophoretic liquid has an ionic conductivity of less than about 100 pmho/cm at 0.1 Hertz.

5. A micro-actuator according to claim 1, wherein the dielectrophoretic liquid has a viscosity of about 0.5 centipoises to about 50 centipoises.

6. A micro-actuator according to claim 1, wherein the dielectrophoretic liquid includes at least one compound selected from the group consisting of phenylmethyl siloxanes, methyl siloxanes, and silanes.

7. A micro-actuator according to claim 1, wherein the dielectrophoretic liquid includes at least one compound selected from 3-phenyl heptamethyl trisiloxane, 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyl trisiloxane, polydimethylsiloxane, polyphenylmethylsiloxane, phenyl-tris(trimethylsiloxy) silane, silanes having Si—

O—

Si backbones, and silanes having Si—

C backbones.

8. A micro-actuator according to claim 1, wherein the dielectrophoretic liquid comprises at least one silane having a backbone substantially free of asymmetrical ether linkages.

9. A micro-actuator according to claim 1, wherein the actuating element is at least one of positioned above the dielectrophoretic liquid and submerged in the dielectrophoretic liquid.

10. A micro-actuator according to claim 1, further comprising:

at least one electrode formed on the surface of the substrate, the electrode having differing dimensions from the actuating element,

wherein the actuating element is adapted to move in response to application of an electrical signal to the at least one electrode and the electrical signal is adapted to form a non-uniform electric field in the cavity.

11. A micro-actuator according to claim 1, wherein the dielectrophoretic liquid is adapted to increase an actuation force on the actuating element as generated by a given activation energy.

12. A method of using a dielectrophoretic liquid in a micro-actuator including an actuator element adapted to move between a first position and at least one second position, the method comprising:

disposing the dielectrophoretic liquid in a cavity of the micro-actuator, including at least one of positioning the actuator element above and submerging the actuator element in the dielectrophoretic liquid; and

moving the actuator element between the first position and the least one second position, including applying an electrical signal to the micro-actuator,

wherein the dielectrophoretic liquid includes at least one compound selected from the group consisting of siloxanes substantially free of asymmetrical ether linkages and silanes substantially free of asymmetrical ether linkages, and

wherein the dielectrophoretic liquid exhibits movement when the electrical signal is applied to the micro-actuator and the movement contributes to the moving of the actuator element between the first position and the at least one second position.

13. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid has a dielectric constant of less than about 20.

14. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid is compressible.

15. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid is polarizable.

16. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid is substantially transparent.

17. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid has a flashpoint greater than about 60 degrees Centigrade.

18. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid has an ionic conductivity of less than about 100 pmho/cm at 0.1 Hertz.

19. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid has a viscosity of about 0.5 centipoises to about 50 centipoises.

20. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid includes at least one compound selected from the group consisting of phenylmethyl siloxanes, methyl siloxanes, and silanes.

21. A method of using a dielectrophoretic liquid according to claim 12, wherein the dielectrophoretic liquid includes at least one compound selected from 3-phenyl heptamethyl trisiloxane, 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyl trisiloxane, polydimethylsiloxane, polyphenylmethylsiloxane, phenyl-tris(trimethylsiloxy) silane, silanes having Si—

O—

Si backbones, and silanes having Si—

C backbones.