Electrical isolation of fluid-based switches

• US 6,770,827 B1
• Filed: 04/14/2003
• Issued: 08/03/2004
• Est. Priority Date: 04/14/2003
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Wong, Marvin Glenn
• Primary Examiner(s): Enad, Elvin
• Assistant Examiner(s): Klaus, Lisa
• Application Number:
  US10/414,129
• Time in Patent Office: 477 Days
• Field of Search: 200/181, 200/182, 200/185, 200/188, 200/190-194, 200/198, 200/199, 200/228, 200/241, 200/243, 200/220-224, 200/233-235
• 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 29/04 Contacts; Containers for liquid contacts
• CPC Class Codes: H01H 29/28 with level of surface of contact liquid displaced by fluid pressure

Abstract

A channel plate is mated to a substrate to define at least a portion of a number of cavities. The channel plate is provided with a switching fluid channel, and a pair of ground channels adjacent the switching fluid channel. A switching fluid is held within a cavity defined by the switching fluid channel, and is movable between at least first and second switch states in response to forces that are applied to the switching fluid. In one embodiment, the ground channels are replaced with ground traces. The ground traces may be formed on or in the substrate or channel plate. Switching circuits incorporating one or more these switches are also disclosed.

Claims

1. A switch, comprising:

a) a substrate;

b) a channel plate, mated to the substrate to define at least a portion of a number of cavities, and comprising;

i) a switching fluid channel; and

ii) a pair of ground channels adjacent the switching fluid channel; and

c) a switching fluid, held within a cavity defined by the switching fluid channel, and movable between at least first and second switch states in response to forces that are applied to the switching fluid.

2. The switch of claim 1, wherein each of the ground channels is lined with a wettable metal.

3. The switch of claim 2, further comprising one or more conductive traces on the substrate that are coupled to the wettable metal lining the ground channels.

4. The switch of claim 3, further comprising solder, wherein the solder couples the one or more conductive traces on the substrate to the wettable metal lining the ground channels.

5. The switch of claim 3, further comprising conductive adhesive, wherein the conductive adhesive couples the one or more conductive traces on the substrate to the wettable metal lining the ground channels.

6. The switch of claim 3, further comprising a liquid metal, wherein the liquid metal couples the one or more conductive traces on the substrate to the wettable metal lining the ground channels.

7. The switch of claim 1, further comprising a liquid metal, held within cavities defined by the pair of ground channels.

8. The switch of claim 7, wherein the switching fluid and liquid metal have the same composition.

9. The switch of claim 1, further comprising a first ground plane running above said channels, and a second ground plane running below said channels.

10. The switch of claim 9, wherein the first ground plane is bonded to a surface of the channel plate that is opposite a surface in which said channels are formed.

11. The switch of claim 9, wherein the second ground plane is a layer of the substrate.

12. The switch of claim 11, wherein the second ground plane is an interior layer of the substrate.

13. The switch of claim 9, wherein the first and second ground planes are electrically coupled to each other and to the ground channels.

14. The switch of claim 1, further comprising a conductive trace on the substrate, wherein:

a) the channel plate further comprises an actuating fluid channel, coupled to the switching fluid channel by a channel that bifurcates one of the ground channels; and

b) portions of the bifurcated ground channel are coupled to one another via the conductive trace on the substrate.

15. A switching circuit, comprising:

a) a substrate;

b) a channel plate, mated to the substrate to define at least a portion of a number of cavities, comprising;

i) first and second switching fluid channels; and

ii) a ground channel located adjacent, and substantially in between, the first and second switching fluid channels;

c) a first switching fluid, held within a cavity defined by the first switching fluid channel, and movable between at least first and second switch states in response to forces that are applied to the first switching fluid; and

d) a second switching fluid, held within a cavity defined by the second switching fluid channel, and movable between at least first and second switch states in response to forces that are applied to the second switching fluid.

16. The switching circuit of claim 15, wherein the channel plate further comprises:

a) a second ground channel adjacent the first switching fluid channel, but not in between the first and second switching fluid channels; and

b) a third ground channel adjacent the second switching fluid channel, but not in between the first and second switching fluid channels.

17. The switching circuit of claim 16, further comprising a first ground plane running above said channels, and a second ground plane running below said channels.

18. A switch, comprising:

a) a substrate;

b) a channel plate comprising a switching fluid channel, mated to the substrate to define at least a portion of a number of cavities;

c) a pair of ground traces adjacent the switching fluid channel; and

d) a switching fluid, held within a cavity defined by the switching fluid channel, and movable between at least first and second switch states in response to forces that are applied to the switching fluid.

19. The switch of claim 18, wherein the pair of ground traces is deposited on the substrate.

20. The switch of claim 18, wherein the pair of ground traces is formed in an interior layer of the substrate.

21. The switch of claim 18, wherein the pair of ground traces is deposited on the channel plate.

22. The switch of claim 18, further comprising a first ground plane running above said channels, and a second ground plane running below said channels.

23. The switch of claim 22, wherein the first and second ground planes are electrically coupled to each other and to the ground traces.