Capacitive key for electronic circuit

• US 3,951,250 A
• Filed: 04/08/1974
• Issued: 04/20/1976
• Est. Priority Date: 04/06/1973
• Status: Expired due to Term

• Current Assignee: Alphameric Keyboards Ltd.
• Original Assignee: Alphameric Keyboards Ltd.
• Inventors: Pointon, Peter, Bial, Wolfgang, Prince, Ian Robert
• Primary Examiner(s): Bagwill, Robert E.
• Assistant Examiner(s): Sewell, Paul T.
• Application Number:
  US05/459,235
• Time in Patent Office: 743 Days
• Field of Search: 178/79, 178/81, 179/90 K, 197/17, 197/98, 200/52 R, 200/DIG. 1, 200/159, 200/267-269, 200/279, 200/292, 235/145, 235/146, 307/88 ET, 340/365 R, 340/365 C
• US Class Current: 200/600
• CPC Class Codes: H03K 17/975 using a capacitive movable element

Abstract

In a keyboard for an electronic circuit having a striker on each key formed of electronic material which is conductive or carries a conductor and which is moved downwardly towards a fixed conductor assembly to provide capacitive coupling, it is found that electrostatic charges can be generated by operation of a key which give spurious outputs. The present invention provides constructions for reducing the effects of such charges.

Claims

1. In a keyboard having keys each carrying a conductive elastomeric striker which striker is movable, by depression of the key, towards conductive elements on a fixed member to effect capacitive coupling therebetween;

the improvement comprising the provision, over said conductive elements, of dielectric material coated with conductive material in regions on its upper surface to be directly contacted by the striker, said conductive elements being adjacent to the other surface of the dielectric material, at least one conductive element being located opposite one of said conductive regions.

3. A keyboard as claimed in claim 1 and having at least two conductive elements, each on the underside of the dielectric material opposite one of said conductive regions on the upper side.

2. An ornamental device to be fastened to clothing and the like to hold glasses and other objects, said device comprising:

a main body having an ornamental front surface;

fastening means attached to the back surface of the main body for fastening the device to clothing and the like;

holding means attached to the back surface of and hidden from frontal view by the ornamental front surface of said main body, said holding means extendable from the bottom edge of said main body for holding objects hung thereover, said holding means comprised of;

two, parallel, vertical, tubular members spaced from each other and attached directly to the back of said main body, and

a moveable U-shaped member frictionally fitted at each vertical section thereof into one of said vertical tubular members, with the horizontal member of the U-shape extending between the vertical sections beneath the vertical tubular members,

whereby extending the U-shaped member beyond the edge of the main body while being frictionally held by the vertical tubular members provides a horizontal support at the bottom horizontal part of the U-shape for holding an object and whereby forcing the U-shaped member upward behind the ornamental front surface completely hides the U-shaped member from frontal view.

4. In a keyboard having keys each carrying a conductive striker element which is movable by the key towards conductive elements on a fixed member to effect coupling therebetween;

the improvement comprising the provision of dielectric material over said conductive elements with at least one conductive element adjacent the lower surface of the dielectric material and with conductive regions on its upper surface to be directly contacted by the striker element, at least one of these regions being located opposite one of said conductive elements adjacent the other side of the dielectric, and wherein said conductive regions on the upper surface of the dielectric material are formed each as areas having a pattern of discrete conductive portions.