Process for manufacturing a composite polymeric circuit protection device

• US 6,640,420 B1
• Filed: 09/14/1999
• Issued: 11/04/2003
• Est. Priority Date: 09/14/1999
• Status: Expired due to Term

• Current Assignee: Littelfuse Incorporated
• Original Assignee: Tyco Electronics Corporation (TE Connectivity Limited)
• Inventors: Hetherton, Scott, Bruguier, Thomas, Daering, Randy, Montoya, Wayne
• Primary Examiner(s): Tugbang, A. Dexter
• Assistant Examiner(s): Kim, Paul D
• Application Number:
  US09/395,869
• Time in Patent Office: 1,512 Days
• Field of Search: 338/22.R, 338/21, 338/313, 338/314, 338/307, 338/309, 338/295, 338/328, 338/332, 296/13, 296/12, 296/11, 296/101, 296/15, 296/19, 296/20, 296/211
• US Class Current: 29/612
• CPC Class Codes: H01C 1/1406 Terminals or electrodes formed on resistive elements having positive temperature coefficient
• CPC Class Codes: H01C 13/02 Structural combinations of resistors impedance networks per se H03H
• CPC Class Codes: H01C 17/006 adapted for manufacturing resistor chips
• CPC Class Codes: H01C 7/021 formed as one or more layers or coatings
• CPC Class Codes: H01C 7/027 consisting of conducting or semi-conducting material dispersed in a non-conductive organic material
• CPC Class Codes: H01C 7/18 comprising a plurality of layers stacked between terminals
• CPC Class Codes: H05K 3/0052 Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards
• CPC Class Codes: H05K 3/403 Edge contacts; Windows or holes in the substrate having plural connections on the walls thereof H05K3/4092 takes precedence
• CPC Class Codes: Y10T 156/1092 All laminae planar and face to face
• CPC Class Codes: Y10T 29/49082 Resistor making
• CPC Class Codes: Y10T 29/49083 Heater type
• CPC Class Codes: Y10T 29/49085 Thermally variable
• CPC Class Codes: Y10T 29/49091 with direct compression of powdered insulation
• CPC Class Codes: Y10T 29/49098 Applying terminal
• CPC Class Codes: Y10T 29/49101 Applying terminal
• CPC Class Codes: Y10T 29/49105 Switch making
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base

Abstract

A process for manufacturing a composite polymeric circuit protection device in which a polymeric assembly is provided and is then subdivided into individual devices. The assembly is made by providing first and second laminates, each of which includes a laminar polymer element having at least one conductive surface, providing a pattern on at least one of the conductive surfaces on one laminate, securing the laminates in a stack in a desired configuration, at least one conductive surface of at least one of the laminates forming an external conductive surface of the stack, and making a plurality of electrical connections between a conductive surface of the first laminate and a conductive surface of the second laminate. The laminar polymer elements may be PTC conductive polymer compositions, so that the individual devices made by the process exhibit PTC behavior.

Claims

1. A process for manufacturing a composite polymeric circuit protection device, said process comprising

(1) providing a polymeric assembly comprising

(a) providing first and second laminates, each of which comprises a Iaminar polymer element having at least one conducive surface;

(b) providing a pattern of conducive material on at least one of the conductive surfaces, and one of which comprises a PTC conductive polymer composition on one laminate;

(c) securing the laminates in a stack in a desired configuration, at least one conductive surface of at least one of the laminates comprising an eternal conductive surface of the stack; and

(d) making a plurality of electrical connections between a conductive surface of the first laminate and a conductive surface of the second laminate, steps (c) and (d) being performed simultaneously; and

(2) subdividing the assembly into individual devices each of which comprises at least one electrical connection.

2. A process according to claim 1, wherein the pattern in step (b) is formed by selectively removing a portion of conductive material from at least one of the conductive surfaces on one laminate.

3. A process according to claim 2, wherein the selective removal of conductive material is accomplished by etching, milling, or stamping.

4. A process according to claim 1, wherein the pattern in step (b) is positioned on one of the external conductive surfaces.

5. A process according to claim 4, wherein the pattern on the external conductive surface is formed by selectively removing a portion of conductive material from the external conductive surface.

6. A process according to claim 4, wherein at least one of the patterned external conductive surfaces is at least partially covered with an insulating layer.

7. A process according to claim 1, wherein an additional conducive layer is added to at least part of at least one of the external conductive surfaces.

8. A process according to claim 1, wherein at least one laminate comprises markings which provide a unique identification of orientation.

9. A process according to claim 8, wherein the markings also provide delineation for subdividing into individual devices.

10. A process according to claim 1, wherein the assembly comprises a third laminate.

11. A process according to claim 1, wherein the laminates are secured to each other in the stack by an adhesive.

12. A process according to claim 1, wherein electrical connection is made between conductive surfaces of the first and second laminates in the stack by (i) forming an aperture which extends through the stack, and (ii) forming a conductive member within the aperture.

13. A process according to claim 1, wherein the electrical connections are positioned so that each of the individual devices comprises at least two electrical connections.

14. A process according to claim 1, wherein the laminar polymer element in each laminate comprises the same PTC conductive polymer composition.

15. A process according to claim 1, wherein the laminar polymer element in each laminate comprises a different PTC conductive polymer composition.

16. A process according to claim 1 wherein the assembly comprises three laminates, each of which comprises a PTC conductive polymer composition.

17. A process according to claim 1, wherein at least one of the laminar polymeric elements comprises a ZTC conductive polymeric material or an NTC conductive polymeric material.

18. A process according to claim 1, wherein at least one of the laminar polymeric elements comprises an insulating polymeric material.

19. A process according to claim 1, wherein the individual devices are subdivided from the assembly using a saw, a shear, a blade, a wire, a waterjet, a snapping device, a laser, or a combination of these.

20. A process according to claim 1 wherein the conductive surface on each laminate comprises a metal foil.

21. A process according to claim 1, which comprises providing a pattern on one of the external conductive surfaces and a pattern on an internal conductive surface.

22. A process according to claim 21, wherein the patterns on the internal and external conductive surfaces are different.

23. A process for manufacturing a composite polymeric circuit protection device, said process comprising

(1) providing a polymeric assembly comprising

(a) providing first and second laminates, each of which comprises a laminar polymer element having at least one conductive surface,

(b) providing a pattern of conductive material on at least one of the conductive surfaces, and one of which comprises a PTC conductive polymer composition on one laminate;

(c) securing the laminates to each other in a stack in a desired configuration by an adhesive, at least one conductive surface of at least one of the laminates comprising an external conductive surface of the stack, and

(d) making a plurality of electrical connections between a conductive surface of the first laminate and a conductive surface of the second laminate; and

(2) subdividing the assembly into individual devices each of which comprises at least one electrical connection.

24. A process according to claim 23, wherein the pattern in step (b) is formed by selectively removing a portion of conductive material from at least one of the conductive surfaces on one laminate.

25. A process according to claim 24, wherein the selective removal of conductive material is accomplished by etching, milling, or stamping.

26. A process according to claim 23, wherein the pattern in step (b) is positioned on one of the external conductive surfaces.

27. A process according to claim 26, wherein the pattern on the external conductive surface is formed by selectively removing a portion of conductive material from the external conductive surface.

28. A process according to claim 26, wherein at least one of the pat ed external conductive surfaces is at least partially covered with an insulating layer.

29. A process according to claim 23, wherein an additional conductive layer is added to at least part of at least one of the external conductive surfaces.

30. A process according to claim 23, wherein at least one laminate comprises markings which provide a unique identification of orientation.

31. A process according to claim 30, wherein the markings also provide delineation for subdividing into individual devices.

32. A process according to claim 23, wherein the assembly comprises a third laminate.

33. A process according to claim 23, wherein electrical connection is made between conductive surfaces of the first and second laminate in the stack by (i) forming an aperture which extends through the stack, and (ii) forming a conductive member within the aperture.

34. A process according to claim 23, when the electrical connections are positioned so that each of the individual devices comprises at least two electrical compositions.

35. A process according to claim 23, wherein the laminar polymer element in each laminate comprises the same PTC conductive polymer composition.

36. A process according to claim 23, wherein the laminar polymer element in each laminate comprises a different PTC conductive polymer composition.

37. A process according to claim 23 wherein the assembly comprises three laminates, each of which comprises a PTC conductive polymer composition.

38. A process according to claim 23, wherein at least one of the laminar polymeric elements comprises a ZTC conductive polymeric material or an NTC conductive polymeric material.

39. A process according to claim 23, wherein at least one of the laminar polymeric elements comprises an insulating polymeric material.

40. A process according to claim 23, wherein the individual devices are subdivided from the assembly using a saw, a shear, a blade, a wire, a waterjet, a snapping device, a laser, or a combination of these.

41. A process according to claim 23 wherein the conductive surface on each laminate comprises a metal foil.

42. A process according to claim 23, which comprises providing a pattern on one of the external conductive surfaces and a pattern on an internal conductive surface.

43. A process according to claim 42, wherein the patterns on the internal and external conductive surfaces are different.