Method and structure for a slug pusher-mode piezoelectrically actuated liquid metal switch

• US 6,768,068 B1
• Filed: 04/14/2003
• Issued: 07/27/2004
• Est. Priority Date: 04/14/2003
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Fong, Arthur, Wong, Marvin Glenn
• Primary Examiner(s): Friedhofer, Michael A.
• Application Number:
  US10/412,869
• Time in Patent Office: 470 Days
• Field of Search: 200/182, 200/187-189, 200/209-219, 200/233-236, 310/328, 310/331, 310/348, 310/363, 335/4, 335/47, 335/78, 385/19
• 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 2057/006 Micromechanical piezoelectric relay
• CPC Class Codes: H01H 29/28 with level of surface of contact liquid displaced by fluid pressure
• CPC Class Codes: H01H 57/00 Electrostrictive relays; Piezoelectric relays

Abstract

A method and structure for an electrical switch. According to the structure of the present invention, a liquid-filled chamber is housed within a solid material. A plurality of switch contacts within the liquid-filled chamber are coupled to the solid material, while a plurality of piezoelectric elements are coupled to a plurality of membranes. The plurality of membranes are coupled to the liquid-filled chamber. The plurality of switch contacts are coupled to a plurality of liquid metal globules, and a slug is coupled to two of the plurality of switch contacts and further coupled to the plurality of liquid metal globules. According to the method, a piezoelectric element is actuated, causing a membrane element to be deflected. The deflection of the membrane element increases pressure of actuator liquid and the increase in pressure of the actuator liquid breaks a slug connection between a first switch contact and a second switch contact and causes the slug to establish a liquid metal connection between a third contact and a fourth contact of the plurality of switch contacts.

Claims

1. A structure for an electrical switch, comprising:

a chamber housed within a solid material, said chamber filled with an actuator liquid;

a plurality of switch contacts within the chamber, wherein the plurality of switch contacts are coupled to the solid material;

a plurality of liquid metal globules, coupled to the plurality of switch contacts and coupled to the chamber;

a slug, coupled to one or more of the plurality of liquid metal globules and coupled to one or more of the plurality of switch contacts; and

a plurality of piezoelectric elements coupled to a plurality of membranes, said plurality of membranes coupled to the chamber.

2. The structure of claim 1, wherein the slug is tapered at one or more ends.

3. The structure of claim 1, wherein the slug is solid.

4. The structure of claim 1, wherein the slug is encapsulated within a liquid metal globule of the plurality of liquid metal globules.

5. The structure of claim 1, wherein the actuating liquid is an inert, electrically nonconductive, low viscosity, low volatility fluid.

6. The structure of claim 1, wherein the plurality of piezoelectric elements are within a reservoir, said reservoir containing actuating liquid.

7. The structure of claim 1, wherein the one or more liquid metal globules are composed of mercury.

8. The structure of claim 1, wherein the plurality of membranes have a corresponding plurality of widths, said corresponding plurality of widths being greater than an extent in a non-actuating direction of the plurality of piezoelectric elements.

9. The structure of claim 1, wherein the plurality of membranes are coupled to a corresponding plurality of orifices, wherein an orifice of the plurality of orifices is operable to increase a rate of flow of the actuating liquid.

10. The structure of claim 9, wherein the plurality of orifices are oriented so that the slug is located between a first orifice and a second orifice of the plurality of orifices.

11. The structure of claim 1, wherein the plurality of piezoelectric elements are further coupled to a corresponding plurality of contacts, said plurality of contacts operable to actuate the plurality of piezoelectric elements.

12. The structure of claim 11, wherein each contact of the plurality of contacts comprise a first terminal coupled to a first end of a piezoelectric element and a second terminal coupled to a second end of the piezoelectric element.

13. The structure of claim 12, wherein the first terminal and the second terminal are separated by a dielectric.

14. A structure for an electrical switch, comprising:

a piezoelectric substrate layer;

an actuator fluid reservoir layer coupled to the piezoelectric substrate layer, said actuator fluid reservoir layer further comprising one or more piezoelectrically actuated pusher elements;

a membrane layer coupled to the actuator fluid reservoir layer, said membrane layer comprising one or more membranes coupled to the one or more piezoelectrically actuated pusher elements;

a liquid metal channel layer coupled to the membrane layer;

a circuit substrate layer coupled to the liquid metal channel layer; and

an actuator liquid-filled chamber housed within the liquid metal channel layer, wherein the actuator liquid-filled chamber comprises one or more globules of liquid metal coupled to one or more switch contacts, a slug coupled to one or more of the one or more globules of liquid metal and coupled to one or more of the one or more switch contacts, wherein said actuator liquid-filled chamber is coupled to the one or more membranes.

15. The structure of claim 14, wherein the plurality of switch contacts are coupled to the circuit substrate layer.

16. The structure of claim 14, wherein the slug is solid.

17. The structure of claim 14, wherein the slug is encapsulated within a liquid metal globule of the one or more liquid metal globules.

18. The structure of claim 14, wherein the actuator fluid reservoir layer further comprises a fill port, said fill port operable to be used for filling a reservoir of the actuator fluid reservoir layer with actuator fluid.

19. The structure of claim 14, wherein the circuit substrate layer further comprises a plurality of circuit traces and a plurality of pads operable to route one or more signals generated by actuation of one or more of the plurality of piezoelectric elements.

20. The structure of claim 14, wherein the actuator liquid is inert and electrically non-conductive.

21. The structure of claim 14, wherein the one or more liquid metal globules are composed of mercury.

22. The structure of claim 14, wherein the plurality of piezoelectric elements are further coupled to a corresponding plurality of contacts, said plurality of contacts operable to actuate the plurality of piezoelectric elements.

23. The structure of claim 22, wherein each contact of the plurality of contacts comprise a first terminal coupled to a first end of a piezoelectric element and a second terminal coupled to a second end of the piezoelectric element.

24. The structure of claim 23, wherein the first terminal and the second terminal are separated by a dielectric.

25. The structure of claim 14, wherein the plurality of membranes are coupled to a corresponding plurality of orifices, wherein an orifice of the plurality of orifices is operable to increase a rate of flow of the actuating liquid.

26. The structure of claim 25, wherein the plurality of orifices are oriented so that to the slug is located between a first orifice and a second orifice of the plurality of orifices.

27. The structure of claim 14, wherein the membrane layer, the actuator fluid the reservoir layer, the piezoelectric substrate layer, the circuit substrate layer and the liquid metal channel layer may be composed of one or more of glass, ceramic, composite material and ceramic-coated material.

28. A method for electrical switching of one or more electrical signals using a liquid metal switch, comprising:

actuating a piezoelectric element;

deflecting a membrane element by the actuation of the piezoelectric element;

increasing a pressure of actuator liquid by the deflection of the membrane element; and

the increase in pressure of the actuator liquid breaking a liquid metal connection between a first switch contact and a second switch contact of a plurality of switch contacts and moving a slug previously coupled to the first switch contact and coupled to the second switch contact so that the slug is coupled to a third switch contact and a fourth switch contact of a plurality of switch contacts.

29. The method of claim 28, wherein the piezoelectric element is actuated by an application of an electric potential applied to a first side and a second opposite side of the piezoelectric element.

30. The method of claim 28, wherein the liquid metal connection is maintained by a surface tension between a liquid metal and the first contact and the second contact.

31. The method of claim 28, wherein prior to an operation of the electrical switch, actuator fluid is added to the liquid metal switch using a fill port.

32. The method of claim 28, wherein an orifice is used to increase a flow rate of actuator liquid caused by the increase in pressure, said increased flow rate operable to more rapidly break the liquid metal connection and move the slug.

33. The method of claim 28, wherein after breaking the liquid metal connection, a second liquid metal connection is established between the second contact and a third contact.

34. The method of claim 33, wherein the slug is encapsulated within a liquid metal of the second liquid metal connection.

35. The method of claim 28, further comprising breaking the second liquid metal connection by application of a second electric potential with a polarity opposite the first electric potential, said second electric potential actuating the piezoelectric element so that a negative pressure is exerted on the membrane element thereby pulling the liquid metal and slug to re-establish the liquid metal connection between the first contact and the second contact and break the second liquid metal connection between the third contact and the second contact.

36. The method of claim 28, further comprising breaking the second liquid metal connection by the use of a second piezoelectric element, a second membrane element, a second electric potential, whereby the second electric potential actuates the second piezoelectric element causing the second membrane element to deflect and increase the pressure of the actuator fluid, said actuator fluid then being operable to flow and break the second liquid metal connection and move the slug.

37. The method of claim 28, wherein the slug is encapsulated within a globule of liquid metal.

38. The method of claim 28, wherein latching is provided by a surface tension of the liquid metal to the contact pads and slug.