Touch panel system
Patent 4698460 Issued on October 6, 1987. Estimated Expiration Date: 
August 26, 2006. 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.
August 26, 2006. 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 3497617 Touch panel system and method Patent #: 4293734 InventorsAssigneeApplicationNo. 06/900646 filed on 08/26/1986US Classes:345/173Touch panelExaminersPrimary: Schreyer, Stafford D.Attorney, Agent or FirmInternational ClassG06F 3/033 (20060101)AbstractA touch panel has panel scanning signals selectively applied to the four sides of a touch sensing surface of the panel so as to establish alternating current voltage gradients in desired directions across the touch sensing surface. When the panel is touched, touch signals or currents result and are utilized by a touch location circuit in determining the location of touch. The impedance touch current resulting from a user's touch may also be determined and used. The touch panel circuit automatically compensates for changes in impedance touch current, such as result when users touch the panel with ungloved and gloved fingers. An analog multiplier is included in the touch location circuit to improve noise rejection. Auto nulling and automatic frequency adjustment is included in the touch panel device, together with overcurrent protection circuitry. | |
