Inventors:
Dale R. Flower - Atlanta GA
Pat Gallarelli - Chapel Hill NC
Kevin P. Goffinet - Cary NC
Anthony W. Miles - Raleigh NC
Charles A. Rudisill - Apex NC
Kevin H. Vorhees - Raleigh NC
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
H03K 1794
Abstract:
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.