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:
Jan. 19, 1999
Filed:
Jul. 15, 1997
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A position detection device that comprises a first substrate, a second substrate, an alternating current (AC) bridge comprised of four variable capacitors, and a detection circuit. The first and second substrates have a flat first electrode surface and a flat second electrode surface, respectively. The second substrate is mounted opposite the first substrate with the first electrode surface opposite the second electrode surface and separated from the second electrode surface by a minute gap. The second substrate and the first substrate are movable relative to one another in the plane of the electrode surfaces. Each of the variable capacitors is composed of a first capacitor electrode located on the first electrode surface and a second capacitor electrode located opposite the first capacitor electrode on the second electrode surface. The capacitor electrodes of two of the variable capacitors are long capacitor electrodes, and the capacitor electrodes of the remaining two of the variable capacitors are short capacitor electrodes. The short capacitor electrodes are shorter than the long capacitor electrodes in the detection direction of the position detection device. The long capacitor electrodes located on the first electrode surface are offset in the detection direction relative to the long capacitor electrodes located on the second electrode surface. The detection circuit derives a position-indicating signal from the output voltage generated by the AC bridge. The position-indicating signal represents the relative position of the first substrate and the second substrate in the detection direction.