International Business Machines Corporation

Kevin P Goffinet

Kevin Hunter Vorhees

Anthony Wayne Miles

Charles Albert Rudisill

Pat Gallarelli

Dale R Flowers

John T Rowe, Jr

Dale R Flower

A touch sensing direct input data display device is described. The data display screen is directly and solely supported within a housing by stiff springs having essentially uniaxial freedom of motion. Strain gauge sensors are applied directly to the springs and are connected in a full Wheatstone bridge sensing circuit. The outputs of the sensors are fed to a calculating and processing device for calculaating the X, Y and Z coordinate information relative to the point on the face of the display which has been pushed or touched. The Z component is of total force and the X any Y components give the two dimensional location for the application of the force measured in the Z axis. The stiff springs allow very little deflection to occur under normal touch imposed fores on the display screen. They permit essentially uniaxial motion only in the Z axis. The system is mechanically robust and may be shipped and subjected to dropping or impact loads normally encountered in shipping without damage, has a relatively high natural frequency of vibration and produces high level, relatively continuous output signals for use.

Touch sensing display screen apparatus

A touch sensing display apparatus having improved electrical signal processing is described. A plurality of signal threshold comparison levels are employed by the electronic signal calculating and processing unit to identify actual touch signals and to exclude extraneous vibration and offset signal components. Static thresholds of comparison are utilized at lower signal levels and a dynamic, signal tracking threshold is utilized at higher signal levels. The apparatus is particularly effective for use in designs employing a suspended CRT display or other display device in which the screen of the display device is directly touched by a user to record selections of information presented or to input graphical or handwritten information.

Touch sensing display screen signal processing apparatus and method

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Cary, NC, United States of America

Kevin P Goffinet