Touch sensor with touch pressure capability
Patent 4933660 Issued on June 12, 1990. Estimated Expiration Date: 
October 27, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
October 27, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3798370 System for producing electric field with predetermined characteristics and edge terminations for resistance planes therefor Electronic pressure sensitive transducer apparatus Bounceless switch apparatus Input device Simplified touch tablet data device Electrographic touch sensor with Z-axis capability Patent #: 4687885 InventorAssigneeApplicationNo. 427785 filed on 10/27/1989US Classes:338/114, Deformable338/99Surfaces pressed together (e.g., compressible type)ExaminersPrimary: Reynolds, Bruce A.Assistant: Lateef, M. M. Attorney, Agent or FirmInternational ClassH01C 010/10AbstractA touch sensor device, and its method of operation, that provides information as to the position of a touch thereon together with information as to the amount of pressure applied to the sensor at the touch position. The device has a pair of spaced-apart membranous sheets with coatings thereon suitable for the determination of position information in a conventional manner. In addition, switching units are included which, during a given time interval of operation, supply a uniform electrical potential in one of the sheets. During that same interval contacts or electrodes on opposite edges of the second sheet are rapidly switched to alternately be oppositely connected to ground on one edge and to the information processing unit at the other edge. In this manner, there is a fixed potential applied to the contact resistance circuit created between the sheets due to the touch pressure, and the alternate switching averages the potential on the second sheet. As a result, the pressure information is substantially independent of the position of touch on the sensor. | |
