Wacom Co., Ltd.

Kabushiki Kaisha Wakom

Toshiaki Senda

Tsuguya Yamanami

Azuma Murakami

Takahiko Funahashi

Toshihide Chikami

Satoshi Inashima

Yoshiaki Tomofuji

Kazuo Aoki

Akio Kikuchi

Takeshi Tanaka

Nobuyuki Miyamori

Keiichi Siguyama

Manabu Abe

Hiroshi Mizuno

A coordinate input system has a tablet composed of an X-direction loop coil assembly and a Y-direction loop coil assembly, and an input pen having a tuning circuit the tuning frequency of which is variable about a predetermined frequency. The system has a coordinate detecting function for detecting the X- and Y-coordinate values of position input by the input pen, and a phase detecting function for detecting the change in the tuning frequency of the tuning circuit as a change in the phase with respect to the phase of the predetermined tuning frequency. Information concerning the detected coordinate point, e.g., spread of the coordinate point proportional to the pressure at which the pen is pressed onto the tablet, is computed in accordance with the amount of change in the phase detected by the phase detecting function.

Coordinate input system and input implement used in the system

A determination is made as to which one of plural objects is proximate a region having a coil therein. Each object includes a tuned circuit having a different resonant frequency. AC energy at the different resonant frequencies is supplied to the coil. The tuned circuit on the particular object in the region having substantially the same resonant frequency as the AC energy supplied to the coil causes a change in the current flowing in the coil at the same resonant frequency. The change in the current flowing in the coil at the same resonant frequency is sensed. In response to the current change at the same resonant frequency the particular object having the tuned circuit with the same resonant frequency as the frequency of the applied AC energy is indicated with a phase detector arrangement responsive to the changed current flowing in the coil at the same resonant frequency and a reference wave at the same resonant frequency. The phase detector arrangement derives indications of the polarities of the phase of quadrature components of the changed current relative to the reference wave and indicates the durations of the polarities relative to predetermined values therefor.

Electronic blackboard system marker and eraser therefor

The position of an implement is determined relative to a tablet including a tuned circuit with a resonant frequency including coils arranged in two coordinate directions. Coils of the tablet are sequentially excited with AC energy having approximately the same frequency as the resonant frequency. The tuned circuit interacts with the AC energy to change the AC current flowing in coils of the tablet as a function of the implement position so the greatest changes in the AC current are in coils of the tablet closest to the implement. Detected values of changes in current as a function of coil position are interpolated to indicate the implement position.

Position detecting apparatus

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

The position on a surface of an implement including a tuned circuit with a predetermined resonant frequency is determined and displayed by an apparatus having a housing including the surface. A tablet in the housing includes coils arranged in two coordinate directions parallel to the surface. The coils are excited with AC energy having approximately the same frequency as the resonant frequency. The tuned circuit interacts with the AC energy to change the AC current flowing in the coils as a function of the implement on the tablet. An electronic two-coordinate direction display in the housing configured as a plate is superposed with and lies in a plane parallel to the tablet and the surface. The display responds to the change in AC current resulting from the interaction between the AC energy and the tuned circuit to indicate the position of the implement on the surface.

Position detecting device

A position detecting apparatus for detecting a position pointed by an input pen which comprises: a position detection section constituted by first and second coil groups each composed of a plurality of loop coils; an input pen having a tuning circuit having a predetermined frequency as a tuning frequency; selector means for successively selecting the loop coils of the first and second coil groups of the position detection section one by one; signal generation means for supplying an A.C. signal of the predetermined frequency to the loop coils; signal detection means for detecting the A.C. signal of the predetermined frequency from the loop coils; and controller means for identifying the position pointed by the position pointer on the basis of the A.C. signal detected by the signal detection means from among the loop coils of the first and second coil groups, whereby the position pointed by the input pen can be detected on the basis of the induced voltages obtained in the first and second coil groups. Because each of the first and second coil groups is constituted by a plurality of patterned coil portions, the position detecting apparatus can be made so as to have high resolution with the reduced number of coils.

A system for detecting the types and statuses of position designating devices is incorporated in a coordinates input apparatus having a tablet constituting a coordinates input section, a plurality of position designating devices of different types, and a position detecting circuit for driving the tablet and detecting positions at which coordinates are input by the position designating devices. The system has an antenna coil disposed around a coordinates input range of the tablet, and a tuning circuit disposed in each of the position designating devices for transmitting radio waves in response to an external signal at an individual frequency determined in accordance with the type of the corresponding position designating device. An AC signal of predetermined frequencies is applied to the antenna coil so that it transmits radio waves. The types and statuses of the position designating devices are detected by judging the condition of the position designating circuits from signals within the antenna coil while the transmission of the radio waves is suspended. With this system, the types and statuses of a plurality of position designating devices can be detected without having to connect the devices to other circuits via cords or provide them with complicated signal generating circuits and power sources such as batteries.

Coordinates input apparatus

A position detecting apparatus for detecting a position pointed by a pointer on a system such as a digitizer has the following parts: a position detection section having a plurality of loop coils arrayed in a side-by-side fashion in the direction of position detection; a selection circuit for successively selecting the loop coils one-by-one; a transmission circuit for generating an A.C. signal of a predetermined frequency to be delivered to the selected loop coil; a receiving circuit adapted to detect an induced voltage of a frequency substantially the same as that of the A.C. signal from among various voltages induced in the selected loop coil; a connection switching circuit for connecting the selected loop coil alternately to the transmission circuit and the receiving circuit; a position pointer having a tuning circuit including a coil and a capacitor and adapted to resonate with an electric wave produced by the loop coil which is supplied with the A.C. signal; and a processing device for determining the position pointed by the position pointer by processing signals representing the levels of voltages induced in the loop coils.

Disclosed is a coordinates input system having a tablet constituting a coordinates input portion, a position designating device such as a stylus pen, and a position detection circuit adapted to drive said tablet and detect a position at which coordinates are input by said position designating device. The system comprises: an antenna coil disposed around a coordinates input range of said tablet; and a tuning circuit disposed in said position designating device and including a coil and a capacitor, wherein radio waves are generated by said antenna coil by application of an AC signal of a predetermined frequency thereto, and the status of said tuning circuit is discriminated by a signal of said antenna coil at the time when the transmission of said radio waves is suspended, thereby detecting the status of said position designating device. Hence, this coordinates input system is capable of detecting the status of the position designating device without connecting the position designating device and other circuits by means of a cord and without providing the position designating device with a conventionally employed complicated signal generating circuit, a battery, and the like.

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Saitama, Japan

Toshiaki Senda