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:
Sep. 07, 2004
Filed:
Jun. 11, 2002
Masaki Ikeda, Kumamoto, JP;
Katsu Tasaki, Fukuoka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
The present invention provides a coordinate data entry device comprising a plurality of receivers disposed in the vicinity of a board surface, and a position indicator to transmit signals, at least one of which employs ultrasonic waves, to the receivers, thereby detecting the position of the position indicator on the board surface and making the coordinate position thereof available for entry, in which the signal employing ultrasonic waves is transmitted at an arbitrary time interval, and an ultrasonic oscillating circuit transmitting the signal employing ultrasonic waves comprises a resonant circuit formed of an ultrasonic resonator and a coil, which are connected in parallel with each other, and the amplitude of a start current of the ultrasonic resonant circuit is made variable according to the lapse of time, thus allowing the variations in performance of the resonant circuit including the ultrasonic resonator to be smoothed out and making stabilized positional detection possible.