Lucent electrographic sensor for determining planar coordinates
First Claim
1. A lucent electrographic sensor for use in determining x- and y-coordinates of a point, which comprises:
- a rigid sheet of transparent substrate;
a substantially transparent, chemically stable uninterrupted resistive layer of a semiconducting metal oxide adherently deposited on one face of the substrate in an amount to produce a sheet resistivity of a selected value in the range of about 100 to 3000 ohms per square;
corner spot electrodes in each corner of the sensor in electrical contact with the resistive layer;
a plurality of spaced-apart edge spot electrodes along each edge of the sensor in electrical contact with the resistive layer;
a plurality of discrete first resistors connected between adjacent of all of the edge spot electrodes; and
a plurality of discrete second resistors connected between the corner spot electrodes and adjacent edge spot electrodes whereby the first and second resistors form series resistor networks along each edge of the sensor.
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Accused Products
Abstract
An electrographic sensor for determining planar coordinates is described whereby graphical material to be analyzed may be placed beneath, or projected against, the rear surface of the sensor. This sensor is of particular value for placing on the face of a cathode ray tube. The sensor includes a rigid, optically transparent substrate having an extremely uniform, substantially transparent resistive layer applied to one surface, small electrodes in contact with the resistive layer and individual resistors connected between adjacent electrodes to produce a resistance network around the perimeter of the substrate. Means are provided to produce orthogonal electrical fields in the resistive layer whereby the contacting of the resistive layer with a conductive stylus produces voltage signals at the stylus which are proportional to the coordinates of the point of contact. The second surface of the substrate may be made translucent for projecting optical images thereagainst.
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Citations
7 Claims
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1. A lucent electrographic sensor for use in determining x- and y-coordinates of a point, which comprises:
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a rigid sheet of transparent substrate; a substantially transparent, chemically stable uninterrupted resistive layer of a semiconducting metal oxide adherently deposited on one face of the substrate in an amount to produce a sheet resistivity of a selected value in the range of about 100 to 3000 ohms per square; corner spot electrodes in each corner of the sensor in electrical contact with the resistive layer; a plurality of spaced-apart edge spot electrodes along each edge of the sensor in electrical contact with the resistive layer; a plurality of discrete first resistors connected between adjacent of all of the edge spot electrodes; and a plurality of discrete second resistors connected between the corner spot electrodes and adjacent edge spot electrodes whereby the first and second resistors form series resistor networks along each edge of the sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification