Abstract: A position pointing device includes a resonant circuit, a resonance-characteristic control circuit for controlling characteristics of the resonant circuit in accordance with pointing-device information at timing synchronized with at least part of an electromagnetic wave that is intermittently transmitted from a tablet and for returning the pointing-device information to the tablet, a clock oscillator circuit for generating a clock signal for driving the resonance-characteristic control circuit, and clock starting means for stopping an operation of the clock oscillator circuit when a start condition is set and for starting the operation of the clock oscillator circuit when the resonant circuit generates a signal specified by the start condition. The position pointing device further includes start-condition setting means for setting the start condition in the clock starting means at timing in accordance with an operation of the resonance-characteristic control circuit.

Abstract: A position indicator contains a resonant circuit. A first resistor having a minimum resistance, a second resistor having a maximum resistance, and a variable resistor whose resistance varies within the range of minimum to maximum resistances are connected to the resonant circuit at first, second, and third specific times based on predetermined timing information supplied from a tablet. Signal levels detected by the tablet at the first and second specific times are used as a lower limit and an upper limit of an operation quantity. Within this range, a signal level detected at the third specific time is converted into an operation quantity. Thus, the continuous quantity can be detected at a fast sampling rate without being influenced by the height and tilt of the position indicator.

Abstract: In a position detecting apparatus, electric power of a position pointer is turned on only when the position pointer is put within a particular range from a tablet to minimize consumption of a battery disposed in the position pointer. When the position pointer is brought close to the tablet, a control signal transmitted from the tablet is detected by a resonant circuit of the position pointer, and MOSFETs serving as a power switch are turned on by the detected signal. In response, electric power is supplied from a battery via the MOSFETs to circuit elements of the position pointer, and thus an operation of the position pointer starts.

Abstract: A position pointing device includes a resonant circuit, a resonance-characteristic control circuit for controlling characteristics of the resonant circuit in accordance with pointing-device information at timing synchronized with at least part of an electromagnetic wave that is intermittently transmitted from a tablet and for returning the pointing-device information to the tablet, a clock oscillator circuit for generating a clock signal for driving the resonance-characteristic control circuit, and clock starting means for stopping an operation of the clock oscillator circuit when a start condition is set and for starting the operation of the clock oscillator circuit when the resonant circuit generates a signal specified by the start condition. The position pointing device further includes start-condition setting means for setting the start condition in the clock starting means at timing in accordance with an operation of the resonance-characteristic control circuit.

Abstract: A position detector includes a position indicator. Transmission/reception of electromagnetic waves relative to the position indicator is performed at least twice while the same loop coil is being selected. With a counter circuit and a switch circuit, a phase difference less than or equal to one cycle of a resonant frequency fO is added to a signal in each transmission/reception. The phase of a reception signal generated at the loop coil is adjusted, and the phase-adjusted signal is used as a detection clock by a synchronous detector circuit to perform synchronous detection. By computing the average or the sum of the results, external noise in the reception signals is cancelled out.

Abstract: A position detector includes a position indicator. Transmission/reception of electromagnetic waves relative to the position indicator is performed at least twice while the same loop coil is being selected. With a counter circuit and a switch circuit, a phase difference less than or equal to one cycle of a resonant frequency fO is added to a signal in each transmission/reception. The phase of a reception signal generated at the loop coil is adjusted, and the phase-adjusted signal is used as a detection clock by a synchronous detector circuit to perform synchronous detection. By computing the average or the sum of the results, external noise in the reception signals is cancelled out.

Abstract: A position indicator contains a resonant circuit. A first resistor having a minimum resistance, a second resistor having a maximum resistance, and a variable resistor whose resistance varies within the range of minimum to maximum resistances are connected to the resonant circuit at first, second, and third specific times based on predetermined timing information supplied from a tablet. Signal levels detected by the tablet at the first and second specific times are used as a lower limit and an upper limit of an operation quantity. Within this range, a signal level detected at the third specific time is converted into an operation quantity. Thus, the continuous quantity can be detected at a fast sampling rate without being influenced by the height and tilt of the position indicator.

Abstract: A coordinate input apparatus includes a position-detecting unit and position-pointing devices. The position-pointing devices include a pen-type position-pointing device and a puck-type position-pointing device provided with a magnetic shielding member or short-circuiting coil for hindering the electromagnetic interaction between sensor coils included in the position-detecting unit and the pen-type position-pointing device. By providing in the puck-type position-pointing device a means for suppressing or cutting the voltage or current of a coil or resonant circuit included in the puck-type position-pointing device, the loading of the pen-type position-pointing device into a pen-type device supporting means provided on the puck-type position-pointing device can deactivate the means for suppressing or cutting the voltage or current of the coil or resonant circuit.

Abstract: A method and apparatus for detecting the positions of a plurality of position indicators using a tablet or the like. After a first position indicator has been detected by an all-scan step, sensor coils to be scanned are specified according to the positional information of the first position indicator. A sector-scan step then performs a more detailed detection of the position of the first position indicator. The sector-scan step and the all-scan step for detecting the approximate position of a second position indicator are implemented alternately. The sector-scan is carried out more frequently than the all-scan.

Abstract: A position detecting apparatus capable of detecting position pointing devices of any combination simultaneously out of plural position pointing devices, thereby providing a user a friendly apparatus. A frequency of a resonance circuit provided inside a position pointing device is set by a command signal transmitted from a tablet, causing plural position pointing devices placed on the tablet to have a different frequencies, thereby suppressing electromagnetic interference among position pointing devices on the tablet, so that a simultaneous detection becomes available.

Abstract: A pen shaped position pointing device used in a position detecting apparatus. A pen-tip segment has side pressure detectors to detect pressure from side directions. The side pressure detectors detect the pen pressure even when the pen is tilted with a large angle. If multiple side pressure detectors are provided, each detector can have a different function, for example, color.

Abstract: A position pointing mechanism for use with a position detecting apparatus, including a pen shaped position pointing device manipulable with one hand of a person operating the mechanism, a rotatable dial having an exposed periphery moveable along the axis of the position pointing device and located on the pen shaped position pointing device so as to be operable with a finger of the one hand in which the position pointing device is held. Provision is made for detecting rotation of the dial, and for detecting relative pressure between the position pointing device and the position detecting apparatus.

Abstract: A position detecting apparatus includes a position point device and a tablet. The position pointing device has a simple configuration as well as an easy way of adjusting a resonance frequency, without requiring a wide range of frequencies for inputting information. The position pointing device has a resonance circuit and an amplitude control circuit that limits a signal level generated in the resonance circuit. The tablet transmits an electromagnetic wave with at least two kinds of energy per transmission, thereby identifying operation of the position pointing device based on a comparison of signal levels received by the tablet.

Abstract: A position pointing pen to be used with a position detecting tablet having multiple sequentially activated coils includes a resonance circuit. In response to the resonance circuit receiving from the tablet a wave having greater than a predetermined amplitude, a sequence of twelve different time slots is established during which loading of the resonance circuit is controlled. During eight of the time slots, the resonance circuit is loaded with pen coordinate information obtained from the tablet coils. During a synchronizing time slot the resonance circuit is loaded by a fixed resistor. During the other three time slots the resonance circuit is loaded with other information, e.g. pen pressure, pen up/down, and color. When a coil of the tablet receives two substantially identical wave sequences from the pen the synchronizing containing slot is extracted and a CPU determines pen position and the other information.

Abstract: A position detecting device and a position pointing device thereof, which are capable of transmitting much information at high speed without lowering the sampling rate of coordinate detection. The position pointing device controls the resonance characteristic of a resonance circuit to one of at least four different resonance characteristics in accordance with at least two bits of binary code out of a plurality of bits of binary code, which represent pointing device information, at a preselected timing. A tablet detects the resonance characteristic of the resonance circuit by resonance characteristic detecting means from an electric wave generated from the resonance circuit at the preselected timing and converts it into at least two corresponding bits of binary code, thus enabling the transmission of information of two bits or more at a time.

Abstract: A position detecting apparatus is equipped with a sense section including a plurality of loop coils arranged parallel to each other along a position detecting direction. The plurality of loop coils are selected in turn by an electric-wave transmission unit to transmit an electric wave. The apparatus is further provided with a position pointing section having a resonance circuit composed of at least one coil and a capacitor. A time-measuring device measures a time period elapsed until a signal developing in the resonance circuit reaches a predetermined level after the electric-wave transmission unit starts the electric-wave transmission.

Abstract: A position pointing device codes information corresponding to an operation expressed by a continuously variable parameter without using an A/D converter and transmits the coded information to a position detecting device. The information corresponding to the operation expressed by the continuously variable parameter is converted into a time length. A counter counts the number of waves of an AC field received by a receiving circuit within the time length determined by the converting circuit, and performs binary coding of the counted value. A control circuit controls an emitter circuit in accordance with the binary code to change an AC field which is sent back to the position detecting device.

Abstract: A position detecting device and a position pointing device therefor transmit information concerning the position pointing device or an operator from a cordless position pointing device to a tablet. An AC field containing information about the position pointing device or the operator and a write instruction is transmitted to the position pointing device by an instruction source of the tablet. The information is stored in a memory of the position pointing device by an instruction extractor responsive to a controller of the position pointing device. The stored information is read out to a characteristic controller in response to an AC field containing a read instruction received by the device from the tablet.

Abstract: A position pointing device for use with a digitizing tablet sequentially transmits plural different kinds of non-positional information to the tablet. The position pointing device varies a resonance characteristic of a resonance circuit in accordance with plural kinds of amount information, during each of plural sequential time slots. A tablet detects a resonance characteristic of the resonance circuit. The frequency and/or amplitude of the AC field coupled from the resonance circuit to the tablet are varied. The frequency variation is sufficiently small that it can be detected with a synchronous detector driven by a single frequency.

Abstract: A position indicator having an oscillation circuit consisting of a first coil for detecting coordinates and a condenser, wherein a control coil and the first coil are placed side by side in such a manner that an induced current running through the first coil surrounds a part of a magnetic flux generated at the first coil and the control coil is controlled to be opened/closed and a distribution of a magnetic flux passing the first coil is varied, which enables an angle of rotation and angle of inclination for the position indicator to be detected.