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:
Nov. 20, 1984
Filed:
Mar. 15, 1983
David D Thornburg, Los Altos, CA (US);
Koala Technologies Corporation, Santa Clara, CA (US);
Abstract
A touch tablet for use in entering data into a computer or graphics display device comprises a first four-sided sheet containing a resistive material on one surface thereof, a second four-sided sheet containing a resistive material on one surface thereof and a spacer for holding the first sheet apart from the second sheet. The first sheet is oriented relative to the second sheet such that the resistive material on one of the two sheets faces the resistive material on the other sheet. Each sheet contains conductive strips formed on two of the four sides of the sheet in contact with the resistive material. A potential is applied across the conductive strips on one of the two sheets. The input lead to an output amplifier is connected to the two conductive strips formed on the other of the two sheets. A user presses the first sheet into conduct with the second sheet and the output voltage from the output amplifier is representative of one of the two coordinates of the point of contact between the two sheets. By connecting the output amplifier to the two conductive strips on the second sheet rather than merely to one conductive strip as in the prior art, the sensitivity of the tablet to noise is reduced and system performance is improved.