Capacitance switch arrangement

• US 4,400,758 A
• Filed: 06/29/1981
• Issued: 08/23/1983
• Est. Priority Date: 06/29/1981
• Status: Expired due to Term

• Current Assignee: Xymox Technologies, Inc.
• Original Assignee: W H Brady Company
• Inventors: Frame, Norman J.
• Primary Examiner(s): Reynolds, B. A.
• Assistant Examiner(s): Keve, Alfred S.
• Application Number:
  US06/278,658
• Time in Patent Office: 785 Days
• Field of Search: 361/283, 361/288, 361/290, 361/328, 361/329, 400/479.1, 340/365 C, 200/DIG. 1, 200/159 B
• US Class Current: 200/600
• 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 2239/006 Containing a capacitive switch or usable as such
• CPC Class Codes: H01H 2239/01 combined with other elements on the same substrate
• CPC Class Codes: H03K 17/975 using a capacitive movable element

Abstract

A capacitance-type membrane switch in which ordinarily spaced-apart contacts are positioned other than directly over an associated capacitance spacing element with an inner insulating layer and outer conductive portions.

Claims

1. A capacitance switch comprising

a substrate,

a first conductive contact carried by said substrate,

a flexible sheet extending over said substrate,

a second conductive contact carried by said flexible sheet and aligned with and ordinarily spaced from said first contact,

a capacitance spacing element carried by one of said substrate and said flexible sheet, located other than directly under or above said contacts,

said capacitance spacing element comprising

an inner insulating layer and

outer conductive portions, one said conductive portion being electrically connected to one said contact, and

first means for connection of the other said contact and the other said conductive portion to external circuitry,

whereby said flexible sheet may be flexed to vary the spacing between said contacts to increase the capacitance of said switch.

2. The switch of claim 1 further comprising a third contact carried by the other of said substrate and said flexible sheet that said capacitance spacing element is carried by, said third contact being electrically connected to second means for connection to external circuitry and being aligned with and ordinarily spaced from said conductive portion not electrically connected to said first means for connection to external circuitry, whereby said flexible sheet may be flexed to vary the spacing between said third contact and said capacitance spacing element.

3. The switch of claim 2 further comprising a fourth contact carried by the other of said substrate and said flexible sheet that said capacitance spacing element is carried by, electrically connected to third means for connection to external circuitry, aligned with and ordinarily spaced from said conductive portion not electrically connected to said first means for connection to external circuitry, and spaced from said third contact, whereby said flexible sheet may be flexed to vary the spacing between said fourth contact and said capacitance spacing element.

4. The switch of claim 2 further comprising a plurality of said capacitance spacing elements and fifth contacts associated with said plurality of capacitance spacing elements, some of said fifth contacts being aligned with and ordinarily spaced from conductive portions of said plurality of capacitance spacing elements, some of said fifth contacts being aligned in ordinarily spaced pairs and being remotely located from but electrically connected to their associated capacitance spacing elements.

5. The switch of claim 4 wherein said contacts are arranged in positions corresponding to positions of typewriter keys, said capacitance elements being aligned with rows of said typewriter key positions.

6. The switch of claim 5 wherein sixth contacts are provided and arranged in pairs in positions corresponding to positions of numerical computation keys, said sixth contacts being located remotely on said switch from said contacts having positions corresponding to said positions of typewriter keys, one said contact of each said pair being electrically connected to a conductive portion of a capacitance spacing element aligned with a corresponding typewriter row.

7. The switch of claim 1 wherein an end of said capacitance spacing element is folded over in the direction away from the sheet that carries it, and said other said conductive portion is in electrical communication with a conductor carried by the sheet that said spacing element is not carried by, whereby all conductors comprising electrical connections to external circuitry can be carried by a single sheet.

8. The switch of claim 7 wherein another end of said capacitance spacing element is folded over in the direction toward the sheet that carries it, and said one conductive portion is in electrical communication with a conductor carried by the sheet and electrically connected to said one contact.