DR. WILLIAM CARY GIBSON, M.D.
Radiology at Park West Blvd, Knoxville, TN

4687885, Aug 18, 1987

Mar 11, 1985

6/710080

John E. Talmage - Oak Ridge TN
William A. Gibson - Knoxville TN

Elographics, Inc. - Oak Ridge TN

G08C 2100

178 18

An electrographic touch sensor having Z-axis capability. In one embodiment, a uniform resistive coating is applied to one surface of a substrate and it is within this coating that orthogonal electrical fields are produced using suitable electrodes and voltage applications to give coordinates of a selected position. Overlying the resistive coating is a flexible pickoff sheet having a conductive layer facing the combination. Interposed between the resistive coating and the conductive layer is an array of a material having a substantially greater resistivity than that of the resistive coating. Signals corresponding to the X- and Y-coordinates of a touched point on the sensor are obtained in a substantially conventional manner using an amplifier and an analog to digital converter. If desired, a Z-axis component signal due to pressure/force can be obtained in a separate part of the measuring cycle. This Z-axis signal is inversely related to a change in the effective contact resistance between the resistive coating and the pick-off sheet caused by the pressure/force.

5886687, Mar 23, 1999

Feb 20, 1997

8/802924

William A. Gibson - Knoxville TN

G09G 500

345173

A touch screen system includes a touch screen having a surface which is adapted to be touched by a user, a resistive substrate which spans the screen and has two opposite boundaries, and a pair of electrodes which are capacitively coupled to the resistive substrate adjacent the two opposite boundaries thereof. The electrodes are adapted to be electrically stimulated from a source to induce reference electrical parameters within the system. Appropriate components are provided for determining changes in electrical parameters at the electrodes as a result of the touch of a location of the screen by the user, and associated componentry is also provided for generating a signal corresponding to the location of the screen touched by the user. The touch screen of the system may be associated with the screen of a CRT for use or placed upon a tabletop for use as a cursor control pad or a keyboard.