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Digitizing Tablet which uses Permuted Grid Connections

IP.com Disclosure Number: IPCOM000107555D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 95K

Publishing Venue

IBM

Related People

Goodwin, JG: AUTHOR [+3]

Abstract

Disclosed is a digitizing pad which consists, in part, of a semi- transparent set of horizontal and vertical conductors forming a Cartesian grid on the surface of a display screen (conductive grid over display in the figure). The wires are insulated from each other, but may be electrically joined by the application of a conductive stylus formed, for example, out of a carbon impregnated elastomer. When the stylus is pressed against the display screen to identify a selected location, one or more of the horizontal wires will be connected electrically to one or more of the vertical wires under the stylus tip.

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This is the abbreviated version, containing approximately 63% of the total text.

Digitizing Tablet which uses Permuted Grid Connections

       Disclosed is a digitizing pad which consists, in part, of
a semi- transparent set of horizontal and vertical conductors forming
a Cartesian grid on the surface of a display screen (conductive grid
over display in the figure).  The wires are insulated from each
other, but may be electrically joined by the application of a
conductive stylus formed, for example, out of a carbon impregnated
elastomer.  When the stylus is pressed against the display screen to
identify a selected location, one or more of the horizontal wires
will be connected electrically to one or more of the vertical wires
under the stylus tip.

      The horizontal and vertical grid, which may consist of several
thousand separate conducting lines across a high resolution display,
are connected to a smaller number of conductive leads along the edges
of the display (32-bit bus in the figure).  The connections are made
in a permuted manner so that the location of any three adjacent
conductors on the display may be uniquely identified by sensing the
conductive leads along the edges of the display.  The use of a 32-bit
bus along the side of the display can provide sufficient information
to determine which three of several thousand gridlines are under the
stylus tip.  (A 16-bit bus can provide enough permuted connections
using three at a time to select among almost two thousand gridlines.)

      Electronic circuitry is used to first det...