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. 20, 1987
Filed:
Nov. 16, 1984
Barry A Blesser, Raymond, NH (US);
Thomas C Prentice, West Newton, MA (US);
Pencept, Inc., Waltham, MA (US);
Abstract
A position indicating implement is disclosed having a first coil connected to a current source and a second coil inductively coupled with the first coil. A capacitor is connected in series with the second coil so that the current in the first coil induces a phase shifted current in the second coil. A tip extends from the barrel of the position indicating implement of the present invention. The tip is designed for placement on and movement over a digitizing tablet. A switch has been located near the tip so that it is easily accessible to a user's finger while holding the implement. The power source providing an alternating current to the first coil includes a digital switching circuit for producing a step function which approximates a sine wave and lacks any components at the second, third, fourth, fifth and sixth harmonics. The step function is filtered to produce a sine wave for delivery to the first coil. The switch near the tip of the implement may be used as a mouse switch so that the position indicating implement may be used as a mouse to indicate relative position rather than absolute position. Remote signaling may be accomplished by providing a switch in the circuit of the second coil. Calibration of the phase shift between the fields of the two coils may be accomplished by providing a line from the circuit of the second coil.