Graphical data entry apparatus
First Claim
1. A graphical entry device comprisinga rigid base member having a flat conductive upper surface,a thin nonconductive plate formed of a material selected from glass or rigid plastic disposed over the base member in close proximity thereto,a layer including resistive material on the underside of the thin plate and extending parallel the conductive upper surface of the base member in spaced relationship therewith,said plate being elastically deformable to engage a point of the resistive material with the conductive surface where depressed,said plate being sufficiently thin to permit substantial capacitive coupling therethrough between a capacitive probe and the resistance layer, andwherein the layer on the underside of the thin plate includesa generally rectangular resistive graphic area with four edges and four corners, each of the four edges defining a midportion separating a pair of spaced joining portions extending from the midportion to the respective corners,four pairs of conductor strips spaced from and extending along the respective pairs of joining portions,four pairs of resistive edge connecting means joining the respective pairs of conductor strips to the respective pairs of joining portions, said resistive edge connecting means each having an effective resistance parallel to the respective joining portions substantially greater than that of the graphic area and the respective conductor strips, andfour conductors connected to respective midportions for providing analog-to-digital converter reference voltages.
1 Assignment
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Accused Products
Abstract
Improvements in graphic tablets employing resistance planes are disclosed including one or more of the following: a tablet usable both by depression and by capacitive probe, reference connections to side midpoints, automatic gain control for capacitive readings, selective high voltage tablet energization for increased resolution reading of a detected region, forming high resistance edges by bending flaps so that resistance flux deposition is oblique to the flaps, separate overlying substrates with edge connecting resistances, and cursor light and/or infrared positioning beam generators.
46 Citations
13 Claims
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1. A graphical entry device comprising
a rigid base member having a flat conductive upper surface, a thin nonconductive plate formed of a material selected from glass or rigid plastic disposed over the base member in close proximity thereto, a layer including resistive material on the underside of the thin plate and extending parallel the conductive upper surface of the base member in spaced relationship therewith, said plate being elastically deformable to engage a point of the resistive material with the conductive surface where depressed, said plate being sufficiently thin to permit substantial capacitive coupling therethrough between a capacitive probe and the resistance layer, and wherein the layer on the underside of the thin plate includes a generally rectangular resistive graphic area with four edges and four corners, each of the four edges defining a midportion separating a pair of spaced joining portions extending from the midportion to the respective corners, four pairs of conductor strips spaced from and extending along the respective pairs of joining portions, four pairs of resistive edge connecting means joining the respective pairs of conductor strips to the respective pairs of joining portions, said resistive edge connecting means each having an effective resistance parallel to the respective joining portions substantially greater than that of the graphic area and the respective conductor strips, and four conductors connected to respective midportions for providing analog-to-digital converter reference voltages.
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2. A graphical entry device comprising an electrically inslated substrate;
- and a patterned layer on the substrate wherein the patterned layer includes
a generally rectangular resistive graphic area with four edges and four corners, each of the four edges defining a midportion separating a pair of spaced joining portions extending from the midportion to the respective corners, four pairs conductor strips spaced from and extending along the respective pairs of joining portions, four pairs of resistive edge connecting means joining the respective pairs of conductor strips to the respective pairs of joining portions, said resistive edge connecting means each having an effective resistance parallel to the respective joining portions substantially greater than that of the graphic area and the respective conductor strips, and four conductors connected to the respective midportions for providing analog-to-digital converter reference voltages.
- and a patterned layer on the substrate wherein the patterned layer includes
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4. A graphic entry apparatus comprising
a member having a planar resistance thereon, a capacitive probe for being moved over the member having the planar resistance and capacitively coupling to selected points thereof; -
means for sequentially energizing the planar resistance with at least first, second and third voltage conditions wherein the first voltage condition produces a voltage gradient across the planar resistance in a first direction, the second voltage condition produces a voltage gradient across the planar resistance in a second direction which is orthogonal to the first direction, and the third voltage condition produces a uniform voltage throughout the planar resistance; means connected to the probe and including amplifier means operated during the first and second voltage conditions for generating signals indicative of the position of the probe; and gain control means connected to the probe and operated during the third condition for controlling the gain of the amplifier means to prevent variations in capacitive coupling between the probe and the resistance from changing the value of position signals. - View Dependent Claims (5, 6)
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7. An analog data tablet apparatus with enhanced resolution comprising
a resistance having at least one elongated dimension, probe means for being selectively coupled with a selected point on the resistance, analog-to-digital converter means connected to the probe means for producing a digital output corresponding to a voltage on the probe means within an analog operating range of voltages, first means for applying a voltage equal to the analog operating range of voltage across the resistance during a first portion of a reading cycle, means responsive to the output of the analog-to-digital converter means for determining a region of the resistance within which the selected point is positioned, and means controlled by the region determining means for applying across the resistance a corresponding one of a plurality of voltages substantially greater than the analog operating range of voltages during a second portion of the reading cycle such that the analog operating range of voltages is produced across the determined region of the resistance whereby the analog-to-digital converter means during the first and second portions of the reading cycle produces respective outputs indicating the position of the selected point with enhanced resolution.
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9. A resistance graphics tablet comprising
first, second and third rectangular substrates positioned on top of each other, a uniform resistance layer covering one side of the first substrate, first and second isolating resistance areas extending on opposite edges of the second substrate, first and second pluralities of connecting means connecting the first and second isolating resistance areas to respective first opposite edges of the uniform resistance layer, third and fourth isolating resistance areas extending on opposite edges of the third substrate, and third and fourth pluralities of connecting means connecting the respective third and fourth isolating resistance areas to respective second opposite edges of the uniform resistance layer.
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11. A cursor device for capacitively coupling to a graphics tablet, comprising
a body having a bottom surface adapted for sliding on the graphics tablet and including a vertical opening therethrough for viewing an area of the tablet, a transparent bottom member extending over the opening on the bottom of the opening, a transparent electrode mounted on the bottom member centrally relative with the opening, and light beam generating means mounted on the body for generate a vertical beam of light concentric with the electrode to enable accurate positioning of the cursor device.
Specification