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:
Aug. 11, 1981
Filed:
Aug. 08, 1979
George Trenkler, East Providence, RI (US);
Richard G Delagi, Sharon, MA (US);
Francois A Padovani, Westwood, MA (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A contactless travel keyboard has first and second coils with elongated loop portions arranged at each key station so that, when an electrically conductive key element at the station is in a key-up position spaced from the coils, electrical input to the first coil results in magnetic induction of a relatively small output signal of a first polarity in the second coil and so that, when the key element moves to a key-down position relatively closer to the coils, electrical input to the first coil induces a current in the key element to magnetically induce a control signal of opposite polarity in the second coil sufficient to reverse the polarity of the output from the second coil. The keyboard includes means responsive to the reversal in polarity of the output signals from the second coils for determining which keys are in a key-down position.