Membrane-type touch panel

• US 4,085,302 A
• Filed: 11/22/1976
• Issued: 04/18/1978
• Est. Priority Date: 11/22/1976
• Status: Expired due to Term

• Current Assignee: St Clair Intellectual Property Consultants Incorporated
• Original Assignee: Control Data Corporation (Ceridian HCM Holding, Inc.)
• Inventors: Zenk, George Edward, Miller, Charles Newell, Johnson, Robert Joseph
• Primary Examiner(s): Schaefer, Robert K.
• Assistant Examiner(s): Ginsburg, Morris
• Application Number:
  US05/743,992
• Time in Patent Office: 512 Days
• Field of Search: 307/116, 307/117, 307/115, 340/324 R, 340/166 R, 340/324 A, 340/365 R, 340/365 C, 340/365 A, 178/18, 178/20, 313/462, 313/478, 313/474, 338/114, 338/2, 338/5, 200/5 A, 200/159 B
• US Class Current: 200/5.00A
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 2201/028 Indium tin oxide [ITO]
• CPC Class Codes: H01H 2209/038 transparent
• CPC Class Codes: H01H 2209/06 transparent
• CPC Class Codes: H01H 2209/082 transparent
• CPC Class Codes: H01H 2211/016 Wires
• CPC Class Codes: H01H 2231/004 CRT

Abstract

A location sensitive touch panel for use on a rigid substrate. The substrate carries a first set of conductive strips. A resilient plastic membrane overlaying it carries a second set of conductive strips orthogonal to and spaced from the first set. Finger pressure can cause electrical contact between any one of the first set of strips and any one of the second set of strips. The substrate may be either flat or curved, with the membrane conforming to its contour.

Claims

1. A switch matrix to be carried on the face of a rigid insulator substrate having a predetermined radius of curvature, and comprising:

a. a plurality of spaced apart conductive first strips firmly adhering to the face of the substrate;

b. a resilient insulating membrane having an undistorted curved contour substantially alike the predetermined contour of the substrate, and attached about its periphery to the face of the substrate in a position matching the membrane contour to the substrate contour and supported apart from the first strips thereon in a predetermined area of the membrane by the natural resilience of the curved contour; and

c. a plurality of flexible, spaced apart conductive second strips firmly adhering to the resilient membrane surface facing the substrate, each of said second strips located in the area spaced apart from the first strips and thinner than the spacing therefrom, and each of said second strips crossing at least two first strips.

2. The switch matrix of claim 1 wherein the first and second strips and the membrane are all transparent.

3. The switch matrix of claim 1, wherein the first conductive strips are substantially parallel to each other the second strips are substantially parallel to each other, and the resilient membrane is oriented to place the second strips substantially orthogonal to the first strips.

4. The switch matrix of claim 1, wherein the substrate contour is convex, and wherein the contour of the membrane is slightly more convex than the contour of the substrate.

5. The switch matrix of claim 4 wherein the substrate contour is spherical.

6. The switch matrix of claim 5 wherein the contour of the membrane has a radius of curvature slightly smaller than that of the substrate.

7. The switch matrix of claim 6, wherein the membrane'"'"'s radius of curvature is about 1 to 4 inches smaller than the substrate'"'"'s.

8. The switch matrix of claim 7 wherein the substrate'"'"'s radius of curvature is approximately 25 inches and the membrane'"'"'s undistored radius of curvature is between about 21 and 24 inches.

9. The switch matrix of claim 1, wherein the resilient membrane comprises polyester film.

10. The switch matrix of claim 1, including an insulating sheet having a contour conforming to the substrate face and fastened thereto in a position matching the sheet'"'"'s contour to the substrate, said sheet on the opposite face thereof carrying the first strips.

11. The switch matrix of claim 10, wherein the sheet, conductive strips, and membrane are all transparent.