The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 11, 1992
Filed:
Feb. 15, 1990
Ronald D Ingraham, Quincy, MI (US);
Nartron Corporation, Reed City, MI (US);
Abstract
A capacity responsive keyboard which eliminates the necessity for metal films on the touch surface includes an insulated substrate having a plurality of electrically conductive plate members mounted thereon and a dielectric member positioned over the plate members. A piece of compressible, electrically-conductive foam is compressed between each plate member and the dielectric member to eliminate air from the electrical path between the dielectric member and the plate members. A grid of conductor segments separates the plate members defining a guard band to reduce interference between the switches. The guard band is connected with one power supply line of a switching circuit which produces outputs in response to capacity changes caused by a user touching the dielectric member.