Adhesive membrane for force switches and sensors

• US 7,468,199 B2
• Filed: 12/23/2004
• Issued: 12/23/2008
• Est. Priority Date: 12/23/2004
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Divigalpitiya, Ranjith, Chen, Pei-Jung, Patel, Vijay, Miholics, Gabriella, Kanno, David A.
• Primary Examiner(s): Nordmeyer; Patricia L
• Application Number:
  US11/021,913
• Publication Number:
  US 20060141192A1
• Time in Patent Office: 1,461 Days
• Field of Search: 428/40.1, 428/40.2, 428/40.4, 428/40.9, 428/42.1, 428/357, 428/378, 428/323, 428/343, 200/512, 200/511
• US Class Current: 428/40.1
• CPC Class Codes: H01H 1/029 comprising conducting material dispersed in an elastic support or binding material
• CPC Class Codes: Y10T 428/14 Layer or component removable to expose adhesive
• CPC Class Codes: Y10T 428/1405 Capsule or particulate matter containing [e.g., sphere, flake, microballoon, etc.]
• CPC Class Codes: Y10T 428/1414 Ceramic, glass, glasslike, vitreous
• CPC Class Codes: Y10T 428/1438 Metal containing
• CPC Class Codes: Y10T 428/1486 Ornamental, decorative, pattern, or indicia
• CPC Class Codes: Y10T 428/249971 Preformed hollow element-containing
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

An adhesive membrane comprises (a) a conductor; (b) a composite material comprising conductive particles at least partially embedded in an electrically insulating layer disposed on the conductor; and (c) a pressure sensitive adhesive layer disposed on the composite material, the conductive particles being capable of electrically connecting the conductor to a second conductor under application of sufficient pressure therebetween, the conductive particles having no relative orientation and being disposed so that substantially all electrical connections made between the conductor and a second conductor will be in the z direction, and the combined thickness of the electrically insulating layer and the pressure sensitive adhesive layer being greater than the size of the largest conductive particle when the largest conductive particle is measured in the z direction.

Claims

1. An adhesive membrane comprising:

(a) a conductor;

(b) a composite material comprising conductive particles at least partially embedded in an electrically insulating layer disposed on the conductor; and

(c) a pressure sensitive adhesive layer disposed on the composite material, the conductive particles being capable of electrically connecting the conductor to a second conductor under application of sufficient pressure therebetween,

the conductive particles having no relative orientation and being disposed so that substantially all electrical connections made between the conductor and a second conductor will be in the z direction,

the combined thickness of the electrically insulating layer and the pressure sensitive adhesive layer being greater than the size of the largest conductive particle when the largest conductive particle is measured in the z direction, and

the electrically insulating layer and the pressure sensitive adhesive layer comprising an elastomeric material that has a substantially constant G′

between about 0°

C. and about 100°

C. and being capable of returning to substantially their original dimensions on the release of pressure,

wherein the adhesive membrane, when combined with a second conductor or electrode, is capable of forming a customized force sensor.

2. The adhesive membrane of claim 1 wherein the conductive particles are disposed so that substantially all electrical connections made between the first and second conductors are through single particles.

3. The adhesive membrane of claim 2 wherein the conductive particles are disposed so that no more than two particles are in contact with each other.

4. The adhesive membrane of claim 3 wherein no two particles are in contact with each other.

5. The adhesive membrane of claim 1 wherein the conductive particles comprise a metal.

6. The adhesive membrane of claim 1 wherein the conductive particles comprise core particles having a conductive coating.

7. The adhesive membrane of claim 6 wherein the core particles comprise glass particles.

8. The adhesive membrane of claim 6 wherein the core particles comprise hollow particles.

9. The adhesive membrane of claim 6 wherein the conductive coating comprises metal.

10. The adhesive membrane of claim 6 wherein the conductive coating comprises a conductive oxide.

11. The adhesive membrane of claim 1 wherein the conductive particles are substantially spherical.

12. The adhesive membrane of claim 1 wherein the conductive particles are fibers.

13. The adhesive membrane of claim 1 wherein at least a portion of the surface of one or more conductive particles is exposed through the electrically insulating layer and the pressure sensitive adhesive layer.

14. The adhesive membrane of claim 1 wherein the electrically insulating layer comprises an elastomeric material that has a substantially constant G′

between about 0°

C. and about 60°

C.

15. The adhesive membrane of claim 1 wherein the pressure sensitive adhesive layer has a substantially constant G′

between about 0°

C. and about 60°

C.

16. The adhesive membrane of claim 1 wherein the electrically insulating layer comprises an elastomeric material that has a G′

between about 1×

10³ Pa/cm² and about 9×

10⁵ Pa/cm² and a loss tangent between about 0.01 and about 0.60 at 1 Hz at 23°

C.

17. The adhesive membrane of claim 1 wherein the pressure sensitive adhesive layer has a G′

between about 1×

10³ Pa/cm² and about 9×

10% Pa/cm² and a loss tangent between about 0.01 and about 0.60 at 1 Hz at 23°

C.

18. The adhesive membrane of claim 1 wherein the electrically insulating layer comprises an elastomeric material that is self-healing.

19. The adhesive membrane of claim 1 wherein the pressure sensitive adhesive layer is self-healing.

20. The adhesive membrane of claim 1 further comprising a device capable of measuring dynamic electrical response across the membrane.

21. The adhesive membrane of claim 1 further comprising a second conductor adhesively bonded to the pressure sensitive adhesive layer opposite the composite material.

22. An adhesive membrane comprising:

(a) a conductor;

(b) a composite material comprising conductive particles at least partially embedded in an electrically insulating layer disposed on the conductor;

(c) a pressure sensitive adhesive layer disposed on the composite material; and

(d) a release liner on an outer surface of the pressure sensitive adhesive layer;

the conductive particles being capable of electrically connecting the conductor to a second conductor under application of sufficient pressure therebetween,

the combined thickness of the electrically insulating layer and the pressure sensitive adhesive layer being greater than the size of the largest conductive particle when the largest conductive particle is measured in the z direction,

the electrically insulating layer and the pressure sensitive adhesive layer comprising an elastomeric material that has a substantially constant G′

between about 0°

C. and about 100°

C. and being capable of returning to substantially their original dimensions on the release of pressure, and

wherein the adhesive membrane, when combined with a second conductor or electrode, is capable of forming a customized force sensor.

23. An adhesive membrane comprising:

(a) a conductor that is permeable to moisture vapor;

(b) a composite material comprising conductive particles at least partially embedded in an electrically insulating layer disposed on the conductor, said electrically insulating layer being permeable to moisture vapor; and

(c) a pressure sensitive adhesive layer disposed on the composite material;

the conductive particles being capable of electrically connecting the conductor to a second conductor under application of sufficient pressure therebetween,

the combined thickness of the electrically insulating layer and the pressure sensitive adhesive layer being greater than the size of the largest conductive particle when the largest conductive particle is measured in the z direction, and

the electrically insulating layer and the pressure sensitive adhesive layer comprising an elastomeric material that has a substantially constant G′

between about 0°

C. and about 100°

C. and being capable of returning to substantially their original dimensions on the release of pressure,

wherein the adhesive membrane, when combined with a second conductor or electrode, is capable of forming a customized force sensor.