Multilayer conductive polymer device and method of manufacturing same

• US 6,172,591 B1
• Filed: 03/05/1998
• Issued: 01/09/2001
• Est. Priority Date: 03/05/1998
• Status: Expired due to Fees

• Current Assignee: Bourns Incorporated
• Original Assignee: Bourns Incorporated
• Inventors: Barrett, Andrew Brian
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): Lee, Kyung S.
• Application Number:
  US09/035,196
• Time in Patent Office: 1,041 Days
• Field of Search: 338/22.R, 338/21, 338/307, 338/309
• US Class Current: 338/22.00R
• CPC Class Codes: H01C 7/027 consisting of conducting or semi-conducting material dispersed in a non-conductive organic material

Abstract

A conductive polymer device has three or more conductive polymer layers sandwiched between two external electrodes and two or more internal electrodes. The electrodes are staggered to create a first set of electrodes, in contact with a first terminal, alternating with a second set of electrodes in contact with a second terminal. A device having three polymer layers is manufactured by: (1) providing (a) a first laminated substructure comprising a first polymer layer between first and second metal layers, (b) a second polymer layer, and (c) a second laminated substructure comprising a third polymer layer between third and fourth metal layers; (2) forming first and second internal arrays of isolated metal areas in the second and third metal layers, respectively; (3) laminating the first and second substructures to opposite surfaces of the second polymer layer to form a laminated structure; (4) forming first and second external arrays of isolated metal areas in the first and fourth metal layers, respectively; (5) forming a plurality of first terminals, each electrically connecting one of the metal areas in the first external array to one of the metal areas in the second internal array, and a plurality of second terminals, each electrically connecting one of the metal areas in the second external array to one of the metal areas in the first internal array; and (6) singulating the laminated structure into a plurality of devices, each having three polymer layers connected in parallel between a first terminal and a second terminal.

Claims

1. A laminated electronic device, comprising:

first, second, and third PTC layers made of a conductive polymer material;

first and second external metal foil electrodes;

first and second internal metal foil electrodes; and

first and second plated metal terminals in direct physical contact with first, second and third PTC layers, the first terminal being in direct physical contact with the first external electrode and the second internal electrode, and the second terminal being in direct physical contact with the first internal electrode and the second external electrode;

wherein a first gap is defined between the first terminal and the first internal electrode, a second gap is defined between the first terminal and the second external electrode, a third gap is defined between the second terminal and the first external electrode, and a fourth gap is defined between the second terminal and the second internal electrode; and

wherein the first PTC layer is laminated between the first external electrode and the first internal electrode so as to be in direct contact with the first external electrode and the first internal electrode, the second PTC layer is laminated between the first and second internal electrodes so as to be in direct contact with the first and second internal electrodes, and the third PTC layer is laminated between the second internal electrode and the second external electrode so as to be in direct contact with second internal electrode and the second external electrode; and

wherein the first terminal is in electrical contact with the first external electrode and the second internal electrode, and the second terminal is in electrical contact with the first internal electrode and the second external electrode, so that the first, second, and third PTC layers are electrically connected in parallel between the first and second terminals.

2. The electronic device of claim 1, wherein the metal foil of the first and second external electrodes and the first and second internal electrodes is made of a material selected from the group consisting of nickel and nickel-coated copper.

3. The electronic device of claims 1 or 2, wherein each of the first and second terminals comprises first and second metal plating layers, wherein:

the first plating layer is formed of a metal selected from the group consisting of tin, nickel, and copper; and

the second plating layer is formed of solder.

4. The electronic device of claims 1 or 2, further comprising:

a first insulating layer on the first external electrode; and

a second insulating layer on the second external electrode.

5. The electronic device of claim 4, wherein the insulating layer is made of glass-filled epoxy resin.

6. The electronic device of claim 4, wherein each of the first and second terminals comprises first and second metal plating layers, wherein:

the first plating layer is formed of a metal selected from the group consisting of tin, nickel, and copper; and

the second plating layer is formed of solder.