Wacom Co., Ltd.

Kabushikikaisha Wacom

Takeshi Tanaka

Azuma Murakami

Yoshiaki Tomofuji

Tsuguya Yamanami

Yoshinori Taguchi

Takahiko Funahashi

Toshiaki Senda

Toshihide Chikami

Satoshi Inashima

Kazuo Aoki

Kenichi Takahashi

A characteristic and the position of an implement with a tuned circuit having one of plural resonant frequencies are determined. AC energy at the plural different resonant frequencies is supplied to a two-coordinate direction coil arrangement of a position sensing tablet. The tuned circuit changes the current flowing in the coil arrangement at the implement resonant frequency. The current change is used to signal the implement position and characteristic. The implement may be an eraser for supplying a signal to an electronic display and for removing a mark from a surface of a visual display overlaying the tablet of the eraser. A housing includes a surface for erasing the marking and two tuned circuits each having a reactance positioned close to opposite edges of the erasing surface. Two switches, when activated, cause the tuned circuits to have different resonant frequencies. The switches are respectively activated when opposite eraser edges are being pushed against the display surface. The implement may also be one of a plurality of markers, each for a different color. Another display responds to the signals to display the position and colors of the markings and selectively remove markings from areas corresponding to the eraser position.

Electronic blackboard and accessories such as writing tools

A position detector comprising a plurality of magnetostriction propagating media extending substantially in parallel with one another and having first coils wound about the media at respective first ends thereof and second coils wound around the media over respective lengths thereof. A current pulse is applied to each of the first coils to generate magnetostrictive oscillation waves in the regions of the mediae around which the first coils are wound. The waves propagate through the media and cause an induced voltage to be generated in the respective second coils at the position where position indicators generate a steady magnetic field. The position of the position indicators is determined by measuring the time that elapses between generating the oscillating waves and receiving the induced voltages. Adjacent two of the plurality of magnetotriction propagating media are respectively paired and each of the magnetostriction propagating media of the respective pairs are individually wound with first coils that are connected together and second coils that are connected together so as to generate a magnetostrictive oscillating wave in the respective pairs. The plurality of magnetositriction propagating media may be evenly spaced or may be irregularly arranged with media that separate pairs being closer together than the media that comprise a pair. In one embodiment the current pulse is applied to the second coils to generate magnetostrictive oscillation waves at the position of the position indicators. In this embodiment the waves propagate through the mediae and cause an induced voltage to be generated in the respective first coil.

Position detector

Growing community of inventors

Saitama, Japan

Takeshi Tanaka