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:
Feb. 16, 1999
Filed:
Jan. 10, 1997
Hartmut Droege, Stuttgart, DE;
Ludwig Fischer, Herrenberg, DE;
Markus Scheibel, Blaufelden, DE;
Dieter Sonnentag, Schoenaich, DE;
International Business Machines Corporation, Armonk, NY (US);
Abstract
A security keyboard is disclosed with a contacting circuit board, a plurality of keys and a switching foil, where the contacting circuit board comprises contact elements necessary for the security keyboard and which is substantially completely enveloped in a security film and in operating the plurality of keys the keyboard pressure is transmitted through the security film to the contacts of the contacting circuit board. In accordance with the invention, the plurality of keys are held in the switching foil in such a way that on operating the plurality of keys a tactile feedback is produced. This permits a positive switching of the security keyboard since, because of the tactile feedback, an `automatic` backpressure of the keys results through a force inflection point, after which an operating force necessary for the operation of the keys, increases again as a consequence, in part, of the security film lying between the key and the contacting means of the security keyboard.