Fluid-based switch

• US 20040200704A1
• Filed: 04/14/2003
• Published: 10/14/2004
• Est. Priority Date: 04/14/2003
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Fong, Arthur, Wong, Marvin Glenn
• Granted Patent: US 6,906,271 B2
• Time in Patent Office: Days
• US Class Current: 200/182
• CPC Class Codes: H01H 2029/008 using micromechanics, e.g. micromechanical liquid contact switches or [LIMMS]
• CPC Class Codes: H01H 29/28 with level of surface of contact liquid displaced by fluid pressure

Abstract

Fluid-based switches and a method for producing the same are disclosed. In one embodiment, the switch comprises first and second mated substrates defining therebetween at least portions of a number of cavities, a plurality of electrodes exposed within one or more of the cavities, a switching fluid that serves to open and close at least a pair of electrodes in response to forces applied to the switching fluid, a surface tension modifier coating at least a portion of the switching fluid, and an actuating fluid, held within one or more of the cavities, that applies the forces to the switching fluid.

Claims

1. A switch comprising:

first and second mated substrates defining therebetween at least portions of a number of cavities;

a plurality of electrodes exposed within one or more of the cavities;

a switching fluid, held within one or more of the cavities, that serves to open and close at least a pair of the plurality of electrodes in response to forces that are applied to the switching fluid;

a surface tension modifier coating at least a portion of the switching fluid; and

an actuating fluid, held within one or more of the cavities, that applies the forces to said switching fluid.

2. The switch of claim 1, wherein the surface tension modifier comprises a composition that reduces the surface tension of the switching fluid.

3. The switch of claim 1, wherein the surface tension modifier comprises an inert liquid with an affinity for the switching fluid.

4. The switch of claim 3, wherein the switching fluid comprises a liquid metal.

5. The switch of claim 4, wherein the liquid metal comprises mercury.

6. The switch of claim 4, wherein the liquid metal comprises a gallium-bearing alloy.

7. The switch of claim 1, wherein the surface tension modifier comprises abietic acid dissolved in a low viscosity fluid.

8. The switch of claim 6, wherein the low viscosity fluid comprises 3M Fluorinert.

9. A switch comprising:

first and second mated substrates defining therebetween at least portions of a number of cavities;

a plurality of wettable pads exposed within one or more of the cavities;

a switching fluid, wettable to said pads and held within one or more of the cavities, that serves to open and block light paths through one or more of the cavities in response to forces that are applied to the switching fluid;

a surface tension modifier coating at least a portion of the switching fluid; and

an actuating fluid, held within one or more of the cavities, that applies the forces to said switching fluid.

10. The switch of claim 9, wherein the surface tension modifier comprises a composition that reduces the surface tension of the switching fluid.

11. The switch of claim 9, wherein the surface tension modifier comprises an inert liquid with an affinity for the switching fluid.

12. The switch of claim 11, wherein the switching fluid comprises a liquid metal.

13. The switch of claim 12, wherein the liquid metal comprises mercury.

14. The switch of claim 12, wherein the liquid metal comprises a gallium-bearing alloy.

15. The switch of claim 9, wherein the surface tension modifier comprises abietic acid dissolved in a low viscosity fluid.

16. The switch of claim 15, wherein the low viscosity fluid comprises 3M Fluorinert.

17. A method comprising:

depositing a surface tension modifier on at least one of the first and second substrates;

depositing a switching fluid on at least one of the first and second substrates; and

mating the first substrate with the second substrate, thereby defining a cavity holding at least a portion of the surface tension modifier and the switching fluid, and thereby forcing the surface tension modifier to coat at least a portion of the switching fluid.

18. The method of claim 17, further comprising selecting a composition of the surface tension modifier so that it reduces the surface tension of the switching fluid.

19. The method of claim 17, wherein depositing a surface tension modifier comprises using a syringe to inject the surface tension modifier into a cavity holding the switching fluid.

20. The method of claim 17, wherein the switching fluid comprises a liquid metal.

21. The method of claim 17, wherein the surface tension modifier comprises abietic acid dissolved in a low viscosity fluid.

22. The method of claim 17, wherein the surface tension modifier and the switching fluid are deposited on at least the same substrate.

23. The method of claim 17, wherein the surface tension modifier and the switching fluid are deposited on different ones of the substrates.