Summagraphics Corporation

Other

Jamie L Barbetti

Thomas C Zalenski

Henry G Matthews

Edward J Snyder

Al Mletzko

An electromagnetic digitizer system employing an interleaved array of individual conductors each in a W configuration bent into plural sections to define plural parallel portions distributed in different segments of a tablet such that each section comprises a center conductor portion connected in series with outer parallel portions such that the current in the center conductor portion splits or divides among the outer conductors and also flows in the opposite direction. Each of the plural sections defines two tablet coarse positions for a pointing device. Interpolation is employed to determine a fine position.

Digitizer tablet with split-current conductor array

A conventional three-electrode wedge-and-strip pattern in a digitizer tablet surface is used with a conventional cursor or stylus. A phantom cursor electrode is located at predetermined coordinates of the active area of the digitizer tablet beneath the X, Y and balance (B) electrodes and separated therefrom by a layer of dielectric material, preferably an air gap. Prior to use of the digitizer apparatus, the phantom cursor electrode is electrostatically coupled to the X, Y and B electrodes in order to obtain data signals representing the phantom cursor's measured coordinates without compensation for resolution distortion. A microprocessor produces a correction factor using the data signals and the predefined coordinates of the phantom cursor electrode, which correction factor is applied in normal use to compensate for resolution distortion resulting from the unavoidable gaps between the X, Y and B electrodes. Also raw measured data obtained from the electrostatically coupled electrodes is adjusted to compensate for environmental and inherent noise and an offset corresponding to the difference in the reference potentials of the integrator and comparator.

Method and apparatus for calibration of a charge ratio digitizer

A charge ratio tablet having three patterned electrodes for determining the position coordinates of a stylus relative to a first area on the tablet is provided with a menu in a second area. The menu includes first and second pluralities of menu electrodes, the three menu electrodes of the first pluralilty having a first geometric pattern and the three menu electrodes of the second pluralilty having a second geometric pattern. The patterned electrodes and menu electrodes are driven in accordance with a predetermined sequence. The processing circuitry determines the position coordinates of the stylus if the signal induced in the stylus in response to driving of the three patterned electrodes simultaneously has at least a predetermined magnitude. The processing circuitry carries out operations other than position coordinate determination if instead the stylus is capacitively coupled to a driven menu electrode. The processing circuitry discriminates which menu electrode is capacitively coupled to the stylus.

Menu for a charge ratio digitizer

An automatic position coordinate determining device comprises a data tablet which has a single magnetostrictive element in which strain waves are induced for determining the position coordinates of a pointer relative to a pair of mutually orthogonal coordinate axes obliquely disposed with respect to the magnetostrictive element. Two mutually orthogonal pluralities of parallel equidistantly spaced electrical conductors form a grid network on the top surface of the tablet. These pluralities of conductors are wrapped around the edge of the tablet and spatially compressed to form respective X and Y conductor grids over opposing quadrants of the tablet bottom surface. A movable pointer travels along the top surface of the tablet while the magnetostrictive element is arranged along the diagonal of the tablet bottom surface. The conductors of the X and Y grids are inductively coupled to the diagonal magnetostrictive element. When the pointer is pulsed, a current pulse is induced in at least one electrical conductor of each plurality, following which oppositely propagating strain waves are induced in the magnetostrictive element by the pulsed electrical conductor. The propagation times of the strain waves are determined and the position coordinates of the pointer are calculated therefrom.

Position coordinate determination device with diagonal delay line

An automatic position coordinate determination device has a single U-shaped delay line made of magnetostrictive material. A grid network of electrical conductors including first and second pluralities of parallel conductors arranged substantially perpendicular to first and second coordinate axes respectively is inductively coupled to the delay line. A sensor coil is arranged at one end of the delay line for outputting a signal in response to the arrival of a propagating magnetostrictive strain wave induced by an energized electrical conductor. A movable flux-producing element is proximally arranged with respect to the grid network. When the flux-producing element is pulsed, at least one electrical conductor of each plurality is energized, which energized conductors in turn each induce a strain wave which propagates toward the sensor. The propagation times of the induced strain waves are processed to determine the position coordinates of the pulsed flux-producing element.

Growing community of inventors

Milford, CT, United States of America

Jamie L Barbetti