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:
Jul. 30, 1991
Filed:
Aug. 31, 1989
Robert B Leach, New Britain, CT (US);
Chester J Slabinski, New Hartford, CT (US);
Jean Youla, Hartford, CT (US);
Otis Elevator Company, Farmington, CT (US);
Abstract
A solid state touch or control button assembly (10), with no moving button parts and operated by capacitive sensing by monitoring the phase shift of a signal applied to the face of the button, including in a first embodiment (FIGS. 2A & 2B) a auto balancing button and in a second embodiment (FIGS. 3A & 3B) a constant pressure button. If skin or other material comes into contact with the touch surface, the capacitance is changed and sensed, causing the electrical or electronic function controlled by the touch button to be activated (or deactivated, depending on the design, or otherwise altered). LEDs then are activated, providing visual feedback to the button pusher through a light ring (2A) surrounding the button surface (1). False activation of the button by residual impedance and external influences, such as temperature change, cleaner residue build-up and other deposits, are avoided by compensating for them by slowly auto balancing to all such phase shifts, with the rate of auto balance being set to be faster than the rate of change of the steady state phase shift; and, additionally, false activations by noise transients, including those due to EMI, FRI and other environmental fluctuations, are avoided by delaying the activation of the button by an appropriate amount of time, such as, for example, of the order of about one hundred (100 msec.) milliseconds.