Flexible capacitive touch sensor

• US 6,819,316 B2
• Filed: 04/17/2001
• Issued: 11/16/2004
• Est. Priority Date: 04/17/2001
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Schulz, Stephen C., Chernefsky, Anthony F., Geaghan, Bernard
• Primary Examiner(s): LAO, LUN YI
• Application Number:
  US09/836,634
• Publication Number:
  US 20020149572A1
• Time in Patent Office: 1,309 Days
• Field of Search: 345/173-183, 463/37-38, 178/18-1-, 178/19-1-, 438/444, 438/445, 438/428, 438/384, 438/780, 428/447, 428/327, 428/429
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A flexible, capacitive touch sensor, and a method of manufacturing a plurality of such touch sensors, are provided. The capacitive touch sensor comprises a thin, flexible, transparent, insulating substrate. A thin, flexible, transparent layer of resistive material is applied to one side of the substrate, and a thin, flexible, transparent, pressure-sensitive layer of adhesive material is applied to the substrate'"'"'s other side. A releasable sheet may cover this adhesive layer. A plurality of thin, flexible electrodes, electrical leads and conductive areas are applied to the resistive layer. A thin, flexible, transparent layer of protective material protects the touch sensor'"'"'s active touch area. Compounds may be added to this protective layer to enhance its conductivity and lubricity. A reel-to-reel process for manufacturing a plurality of such capacitive touch sensors also is described.

Claims

1. A method of manufacturing a plurality of flexible, capacitive touch sensors, comprising:

providing a thin, flexible, transparent substrate, said substrate having a first side, a second side and being sufficiently large for division into a plurality of separate sections, each of said sections corresponding to one of said capacitive touch sensors;

causing said substrate to pass a plurality of processing stations;

applying at one or more of said processing stations a first layer of resistive material on said first side, said first layer being thin, transparent, electrically continuous and flexible;

applying at one or more of said processing stations a plurality of thin, flexible electrodes in electrical communication with said first layer, said electrodes being positioned along the peripheries of each said section and adapted to apply within each said section an electrical potential across the portion of said first layer corresponding to said section;

applying at one or more of said processing stations a plurality of thin, flexible, electrical leads in electrical contact with said electrodes for transmitting electrical signals to and from said electrodes, said electrical leads being positioned along the peripheries of each said section;

applying at one or more of said processing stations a plurality of thin, flexible conductive areas in electrical communication with said first layer, said conductive areas being positioned along the peripheries of each said section and forming a pattern adapted to linearize within each said section the electrical potential across the portion of said first layer corresponding to said section; and

cutting at one or more of said processing stations through said first layer and said substrate along the peripheries of each said section to provide said plurality of capacitive touch sensors.

2. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, further comprising:

applying at one or more of said processing stations a second layer of protective material on one of said first layer and said second side, said second layer being thin, transparent, flexible and covering within each of said sections substantially the entire surface of one of said first layer and said second side; and

cutting at one or more of said processing stations thin, elongated lines in said first layer along the peripheries of each said section between said conductive areas and said electrical leads to substantially electrically isolate along said peripheries said conductive areas from said electrical leads.

3. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said protective material comprises one or more compounds selected from the group consisting of organosiloxanes and fluorocarbons to reduce the coefficient of friction of said protective material.

4. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 2, wherein said second layer is deposited by spraying.

5. A method of manufacturing a plurality of flexible capacitive touch sensors as in claim 2, wherein said second layer is deposited by Gravure coating.

6. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 2, wherein said cutting of said thin, elongated lines is effected by a laser.

7. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said first layer is continuous.

8. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said causing said substrate to pass said plurality of processing stations comprises winding said substrate from a holding reel onto a receiving reel.

9. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, further comprising applying at one or more of said processing stations a third layer of adhesive material on one of said second side and said first layer, said adhesive material being thin, transparent and flexible.

10. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 9, wherein said third layer is pressure sensitive and covers within each of said sections substantially the entire surface of one of said second side and said first layer.

11. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 9, further comprising applying at one or more of said processing stations a releasable sheet over the exposed surface of said third layer.

12. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said substrate is a sheet of material selected from the group consisting of polyethylene terephthalate, polycarbonate polyester, polyvinyl chloride, polyether sulfone, polyimide, polyether imide, cellulose triacetate and polyethylene naphthalate.

13. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said resistive material is a transparent conductive oxide selected from the group consisting of indium tin oxide, indium oxide, silicon indium oxide, aluminum zinc oxide, indium zinc oxide, antimony tin oxide and tin oxide.

14. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said resistive material is indium tin oxide.

15. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said first layer is deposited by sputtering.

16. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said electrodes, said leads and said conductive areas comprise conductive ink.

17. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 16, wherein said electrodes, said leads and said conductive areas are deposited by screen printing.

18. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 16, wherein said electrodes, said leads and said conductive areas are deposited by ink-jet printing.

19. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, further comprising applying at one or more of said processing stations a fourth layer of conductive material on said second side, said fourth layer being thin, continuous, flexible, transparent and covering within each of said sections substantially the entire surface of said second side.

20. A method of manufacturing a plurality of flexible, capacitive touch sensors as in claim 1, wherein said cutting through said first layer and said substrate is effected by a laser.