LOW-COST MASS-PRODUCED TOUCH SENSORS

• US 20120019475A1
• Filed: 07/26/2010
• Published: 01/26/2012
• Est. Priority Date: 07/26/2010
• Status: Active Grant

• Current Assignee: Pure Imagination LLC
• Original Assignee: Pure Imagination LLC
• Inventors: Campbell, Paul P., Le, Khanh M., Holmes, David M., Li, Jeffrey
• Granted Patent: US 9,092,096 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer

Abstract

A capacitive touch sensor has a clear top plastic film and graphics or other designs disposed on its reverse side. Only the bare plastic substrate is exposed to the environment and user wear. Non-conductive color inks are used in printing the graphics so that any printed capacitive sensors in contact behind will not be short circuited or desensitized. A silk-screened base color layer with a print-free margin left all around its edges allows a later application of adhesive to grip a more durable surface underneath. Capacitive touch sensors are deposited on a bottom plastic film with silvered conductive inks. The printed capacitive sensors on film are fastened with a silk-screen applied liquid water-based adhesive and face the graphics printed side of the first plastic film. A final overcoat of adhesive is applied to the bare backside of the bottom plastic film for final assembly to a frame or chassis.

Claims

1. A capacitive touch sensor, comprising:

a clear first plastic film on which reverse-image graphics and designs are disposed only on a reverse side, and wherein a bare clear plastic surface on a front side is ultimately exposed to the environment and user wear;

non-conductive color inks are included in said graphics and designs such that any printed sensors located immediately behind are not electrically short-circuited nor desensitized by their mutual contact or proximity;

a second plastic film with a pattern of printed electronic capacitive touch sensors that are deposited or etched with conductive inks or foils, and positioned behind the non-conductive color inks;

a masking layer positioned to obscure the printed electronic capacitive touch sensors from view; and

an adhesive lamination layer that joins a graphics printed side of the first plastic film using a silk-screen applied liquid water-based adhesive.

2. The capacitive touch sensor of claim 1, further comprising:

a mask-free margin left around the outside edges in the silk screening of the masking layer.

3. The capacitive touch sensor of claim 1, further comprising:

a final overcoat of adhesive applied to the bare backside of the second plastic film for final assembly to a frame or chassis.

4. A touch-operated electronics assembly, comprising:

a first plastic film having a front side for exposure to the environment and users and a back side, and comprising clear materials;

a reverse-image non-conductive ink printing disposed on said back side of the first plastic film; and

a patterned layer of conductive inks configured for electronic touch sensing on the front side of the first plastic film, and having features registered and mapped to particular graphics represented in the reverse-image non-conductive ink printing, and assembled behind the reverse-image non-conductive ink printing and back side of the first plastic film.

5. The touch-operated electronics assembly of claim 4, further comprising:

an adhesive layer disposed between the reverse-image non-conductive ink printing disposed on said back side of the first plastic film and the patterned layer of conductive inks; and

a second plastic film on which the patterned layer of conductive inks is disposed on a front side.

6. The touch-operated electronics assembly of claim 4, further comprising:

an adhesive layer disposed between the reverse-image non-conductive ink printing disposed on said back side of the first plastic film and the patterned layer of conductive inks; and

a second plastic film on which the patterned layer of conductive inks is disposed on a back side.

7. The touch-operated electronics assembly of claim 4, further comprising:

a supporting frame in which the other components are disposed and braced.

8. The touch-operated electronics assembly of claim 4, further comprising:

a second plastic film on which the patterned layer of conductive inks is disposed on a back side;

an adhesive layer disposed between the reverse-image non-conductive ink printing disposed on said back side of the first plastic film and the second plastic film; and

a mask-free margin in a masking layer such that the perimeter edges of the first plastic film is exposed to adhesive;

wherein the patterned layer of conductive inks is applied to the back side of the second plastic film.

9. The touch-operated electronics assembly of claim 4, further comprising:

a supporting frame in which the other components are disposed and braced;

an adhesive layer disposed between the supporting frame and the reverse-image non-conductive ink printing disposed on said back side of the first plastic film;

wherein the patterned layer of conductive inks is applied to the back side of the reverse-image non-conductive ink printing.

10. The touch-operated electronics assembly of claim 4, wherein the reverse-image non-conductive ink printing disposed on said back side of the first plastic film includes an opaque mask.

11. The touch-operated electronics assembly of claim 4, further comprising:

a baseboard disposed immediately behind the reverse-image non-conductive ink printing disposed on said back side of the first plastic film, and providing for support and bracing.

12. The touch-operated electronics assembly of claim 4, further comprising:

an adapter for flipping circuit conductors from one side of a connection to the patterned layer of conductive inks to another side, and including an anisotropic conducting film tape with pressure sensitive adhesive.