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:
Mar. 29, 1988
Filed:
Mar. 16, 1987
Waldo L Landmeier, Scottsdale, AZ (US);
CalComp, Inc., Anaheim, CA (US);
Abstract
In a digitizer system, adjacent conductors in pairs are looped through four quarter sections of a grid active area in such a way that the unexcited polarities of the pair are different in each quarter section. A coil in a pen tip is moveable relative to the grid, and used to inductively couple signals in the conductors of the grid. The number of conductors required to span a given grid active area, and the number of multiplexers required to handle such conductors, are reduced by a factor of four. The polarities of signals induced in the conductors by the coil are selectively changed depending upon the quarter section in which the coil is located and sampled to coarsely locate the coil as being between two particular adjacent conductors. In the disclosed embodiment, a ratio of the magnitudes of the signals induced in the two particular conductors is then used to precisely locate the coil between these two adjacent conductors.