Conversion System

Abstract

Abstract 1,168,427. Measuring co-ordinate positions electrically. LITTON INDUSTRIES Inc. March 28, 1968 [April 3, 1967], No. 15069/68. Heading G1N. Apparatus for determining the X, Y co-ordinates of a point on e. g. the surface 20 Fig. 2 of a CRT comprises a conductive-coated transparent membrane 14 located over a resistive-coated transparent glass plate 18, covering the face of the CRT, and fed with an X and Y voltage pattern, so that the voltage picked up by the membrane when it is depressed at a test point 22 to contact the glass plate are indicative of the X, Y coordinates of that point. The resistive-coating of glass plate 18 has a plurality of terminals 60-82 Fig. 5 round its circumference fed with sine and cosine voltages to form a rectangular co-ordinate system of equipotential lines. These voltages may be D. C., fed alternately to produce first the X co-ordinate system then the Y coordinate system, or they may be alternating voltages of different frequencies. The inner, conducting surfaces of the membrane 14 and glass 18 are hermetically sealed by gaskets. In a modification Fig. 6 (not shown), the contacting members each consist of an insulating membrane coated on the facing sides with a parallel grid of conducting lines, with the grids at right angles, fed alternately with voltages forming equi-spaced potential lines. In another modification Fig. 8 (not shown), a third membrane is located between the grid membranes, and is made separately conductive on each face to act as the leads for the X, Y voltages.

Inventors

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Bibliographic Details