Abstract: A touch tablet (10) for determination of x-axis and y-axis coordinates of point touched includes a two-layer operating structure, each layer (11,21) containing a resistive bar (12,22) at an edge portion of an insulative substrate and a series of interdigitated conductive pathways (14,15) extending toward and away from the bar and an opposed conductive strip (13,33,43) on at least one of the layers. The bars and conductive pathways are orthogonally with respect to one another on each layer and further are orthogonal on one layer with respect to those bars and pathways on the other layer. A potential typically of 5 V is impressed on either one end of each of the resistive bars or on the interdigitated pathways.The two layers (11,21 or 31,41) are normally spaced from each other by insulative dots (6) on one facing surface or by an embossed peripheral ridge (56) on the top surface.
Abstract: Interface circuitry is provided for interconnecting a source of positional data such as a touch tablet with a computer interface. The circuitry acquires voltages from the source of positional data which represent the data. An acquired voltage is compared with a ramped voltage. At the time of crossover the internal capacitor of the computer interface is rapidly charged above the threshold level to provide positional data from the external source to the computer interface.
Abstract: A touch tablet is provided containing two sheets of insulating material each of which contains a plurality of spaced apart conductive lines. A resistive strip on each sheet contacts and connects electrically one end of each of the plurality of conductive lines on that sheet. Each resistive strip functions as a potentiometer. Mounted between the two sheets and spaced apart therefrom is a conductive middle sheet. The first and second sheets are mounted such that the first and second sets of a plurality of conductive lines on these sheets are orthogonal to each other. A user presses on one of the two sheets to bring all three sheets into contact. The impedence of each potentiometer is a function of the contact point. The potentiometer is used as part of an RC circuit to provide a variable time constant representative of the coordinate of the contact point.
March 15, 1983
Date of Patent:
February 11, 1986
Koala Technologies Corporation
David D. Thornburg, George M. White, III
Abstract: A digitizer pad has multiple contact points between facing conductive or resistive coated surfaces of spaced planar sheets (11,16). The sheets are joined by an energy-storing hinge means (13) at the periphery of the respective sheets. Pressing of a top sheet against the bottom sheet by a stylus or operator finger force makes a finite electrical point contact, or series of discrete electrical contacts as the stylus or finger is moved across the top sheet while continuing to depress the sheet, and the X-Y coordinates of the contact(s) determined and indicated on a video screen or the like. Release of the energy stored in the hinge by depression of the top sheet returns sheet (11) into separated position from sheet 13 at that point of contact.
Abstract: A touch tablet for use in entering data into a computer or graphics display device comprises a first four-sided sheet containing a resistive material on one surface thereof, a second four-sided sheet containing a resistive material on one surface thereof and a spacer for holding the first sheet apart from the second sheet. The first sheet is oriented relative to the second sheet such that the resistive material on one of the two sheets faces the resistive material on the other sheet. Each sheet contains conductive strips formed on two of the four sides of the sheet in contact with the resistive material. A potential is applied across the conductive strips on one of the two sheets. The input lead to an output amplifier is connected to the two conductive strips formed on the other of the two sheets. A user presses the first sheet into conduct with the second sheet and the output voltage from the output amplifier is representative of one of the two coordinates of the point of contact between the two sheets.
Abstract: A hand controller for use in controlling the motion of a cursor on a video display comprises a spherical surface on which is mounted a flat plate. On the bottom of the flat plate is a unique electrical switch capable of indicating the direction in which the flat plate is rocked over the spherical surface. Attached to the bottom of the flat plate adjacent the spherical surface is a spring consisting of a substantially flat center portion and four spiralling arms extending from the periphery of said center portion to attach to the structure on which the spherical surface is mounted. When the flat plate is rocked over said spherical surface, the spring generates a restoring force which, upon removal of the rocking force, restores the flat plate to its nominal position. The spring makes possible rocking motion of the flat plate over the spherical surface without pinning the flat plate to a point on the spherical surface.