The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 26, 1999
Filed:
Oct. 21, 1997
Bhusan Gupta, Palo Alto, CA (US);
Alan Henry Kramer, Berkeley, CA (US);
STMicroelectronics, Inc., Carrollton, TX (US);
Abstract
A fingertip-operated solid state capacitance switch detects a capacity change that is induced by the physical contact of an ungrounded fingertip to an external dielectric surface of the solid state switch. The input and output of a solid state signal-inverting amplifier are respectively connected to two relatively large and ungrounded capacitor plates that are associated with, but electrically isolated from, the switch's external dielectric surface. An ungrounded fingertip forms a third capacitor plate on the switch's external surface. The solid state amplifier detects the presence of a fingertip on the switch's external surface by way of a change in capacitance within a compound, three plate, capacitor that includes the two ungrounded capacitor plates and the ungrounded fingertip that is resident on the switch's external surface. An automatic gain control circuit is provided to adjust the value of an amplifier reference voltage when the solid state switch is not operating, thereby allowing the solid state switch to adapt to changeable ambient conditions. A momentary switch and a toggle flip-flop latched switch are provided. A linear switch array having a movable control knob and a linear LED indicator array is provided. The momentary solid state switch is constructed to operate as a temporal code detector that detects a coded sequence of switch-taps and a coded time interval between adjacent switch-taps.