JP2004318844A - Position detection system and position detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an area of undetectable positions of a position pointing unit in an electromagnetic coupling type position detection system. <P>SOLUTION: In a position detection device 100, a transmission selection part 104, in the control of a control part 101, selects either of a plurality of concentrically arranged transmission coils 111 and 112 in dependence on the position of the position pointing unit 120, and outputs a position detecting signal generated by a transmission signal generation part 102 to the selected transmission coil. The selected transmission coil transmits the position detecting signal to the position pointing unit 120. A reception selection part 108 sequentially selects a plurality of sensor coils 113, which receive a position pointing signal from the position pointing unit 120 as a detection signal. The position pointing signal sequentially received by the sensor coils 113 is output via a reception amplifier 109 to a detection part 110, which detects the pointing position of the position detection unit 120 according to the detection signals. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a position detection device which is used as an input device of a CAD (Computer Aided Design), a computer, a personal digital assistant (PDA), etc., and detects a position indicated by a position indicator by electromagnetic coupling, the position indicator, and position detection. The present invention relates to a position detection system using a device.

Conventionally, as an input device of a CAD or an input device of a computer, a signal is transmitted and received between a position indicator and a position detecting device by electromagnetic coupling, and a position indicated by the position indicator is detected by the position detecting device. The electromagnetic coupling type position detection system described above is used.
For example, in a system in which a transmission coil is provided on an outer peripheral portion of a sensor region in a position detection device as in the invention described in Patent Literature 1, one transmission coil is provided.

  FIG. 10 is a diagram showing a schematic configuration of a sensor unit of the position detecting device described in Patent Document 1. In FIG. 10, one transmission coil 1001 is arranged on the outer periphery of a plurality of sensor coils 1002. Note that, for simplification of the drawing, only the sensor coil in the X direction is shown as the sensor coil 1002, and the sensor coil in the Y direction is omitted.

In FIG. 10, a position detection signal is transmitted from a transmission coil 1001 to a position indicator (not shown) by electromagnetic coupling, and then a plurality of sensor coils 1002 are sequentially selected and driven. The position indication signal is sequentially received by the plurality of sensor coils 1002 by electromagnetic coupling, and the position of the position indicator is detected based on the detection signals received by the plurality of sensor coils 1002.
As described above, the position detection system described in Patent Document 1 has an advantage that the use of one transmission coil 1001 simplifies the transmission circuit of the position detection signal used for position detection.
JP-A-5-88811

  However, in the position detection system, when the center of the position indicator is located directly above the transmission coil 1001, the position indicator cannot be excited by the position detection signal, so that position detection is not possible. There is a problem that it becomes possible.

As a method for preventing this, it is conceivable to arrange the transmission coil 1001 so as to be wound outside the reception sensor coil 1002. This can solve the problem that the position indicator cannot be excited and the position cannot be detected.
However, there is a problem that an area where the position of the position indicator cannot be detected because the receiving sensor coil 1002 does not exist, that is, an invalid area 1003 between the transmitting coil 1001 and the receiving sensor coil 1002 increases.

An object of the present invention is to reduce a region in which the position of a position indicator cannot be detected in an electromagnetic coupling type position detection system.
An object of the present invention is to reduce a region where the position of a position indicator cannot be detected in an electromagnetic coupling type position detecting device.

  According to the present invention, a position indicator having at least one coil for indicating a position, and transmitting and receiving a signal between the position indicator by electromagnetic coupling to thereby indicate a position indicated by the position indicator. In the position detection system having a position detection device for detecting, the position detection device, a plurality of transmission coils for transmitting a signal for position detection to the position indicator, and for receiving a signal from the position indicator A plurality of sensor coils and a signal for selecting one of the plurality of transmission coils according to the position of the position indicator and driving the selected transmission coil so as to transmit the position detection signal Transmitting means; receiving means for sequentially selecting the plurality of sensor coils to receive a signal from the position indicator; and a finger of the position indicator based on the signal received by the receiving means. Position detection system, characterized by comprising a position detecting means for detecting the position is provided.

  The signal transmission means selects one of the plurality of transmission coils according to the position of the position indicator, and drives the selected transmission coil so as to transmit the position detection signal. The receiving means sequentially selects a plurality of sensor coils and receives a signal from the position indicator. The position detecting means detects a position indicated by the position pointing device based on the signal received by the receiving means.

Here, the plurality of transmitting coils may be configured to be concentrically arranged.
Further, the signal transmitting means divides a sensor area in which the plurality of transmitting coils are arranged into a plurality of areas, and detects the largest position detection relative to the position indicator in the area where the position indicator is located. The position detection signal may be supplied by selecting and driving a transmission coil capable of supplying a signal.
Further, a configuration may be adopted in which a capacitor constituting a series resonance circuit is provided together with each of the transmission coils.
Further, the capacitor may be configured to be a single capacitor commonly connected to the plurality of transmission coils.
In addition, the signal transmission unit reverses the phase of the position detection signal supplied to the position indicator based on the position of the position indicator detected by the position detection unit and the relative positional relationship of the selected transmission coil. The selected transmission coil may be configured to be driven so as not to perform the transmission.

Further, the signal transmitting means reverses the phase of a signal for driving the transmission coil depending on whether the position indicator is located inside or outside the transmission coil and always keeps the position indicator in phase with the position indicator. May be configured to transmit the position detection signal.
Further, the plurality of transmission coils may be constituted by a first transmission coil and a second transmission coil arranged concentrically outside the first transmission coil.

Further, when the position detection signal is transmitted in a first phase in a sensor area where the position of the position indicator can be detected, the position of the first transmission coil is higher than that of the second transmission coil. A first area in which a signal for detection can be transmitted, the second transmission coil transmits a position detection signal having a level larger than that of the first transmission coil when the position detection signal is transmitted in the first phase; A second area in which transmission is possible, wherein the position of the first transmission coil is higher than that of the second transmission coil when the position detection signal is transmitted in a second phase inverted from the first phase. Signal is divided into a third area that can be transmitted,
The signal transmitting means transmits the position detection signal at the first phase from the first transmission coil when the position indicator is located in the first area, and the position indicator is When the position indicator is located in the second region, the position detection signal is transmitted at the first phase from the second transmission coil, and when the position indicator is located in the third region, the first position detection signal is transmitted. The transmission coil may transmit the position detection signal at the second phase.

  Further, when the position indicator is located in the first area, the receiving means sequentially selects a plurality of predetermined sensor coils disposed in the first area and the periphery thereof, and receives a signal from the position indicator. When the signal is received and the position indicator is located in the second area, a predetermined plurality of sensor coils disposed in the second area and the periphery thereof are sequentially selected to output a signal from the position indicator. Receiving, when the position indicator is located in the third area, sequentially selecting a plurality of predetermined sensor coils disposed in the third area and the periphery thereof and receiving a signal from the position indicator It may be configured as follows.

Further, according to the present invention, position detection for detecting a position indicated by the position indicator by performing transmission and reception of signals by electromagnetic coupling with a position indicator having at least one coil for indicating a position. In the device, a plurality of transmission coils for transmitting a position detection signal to the position indicator, a plurality of sensor coils for receiving a signal from the position indicator, and according to a position of the position indicator A signal transmission unit that selects any one of the plurality of transmission coils and drives the selected transmission coil so as to transmit the position detection signal; and sequentially selects the plurality of sensor coils to determine the position. It is characterized by comprising receiving means for receiving a signal from an indicator, and position detecting means for detecting an indicated position of the position indicator based on a signal received by the receiving means.置検 out device is provided.
The signal transmission means selects one of the plurality of transmission coils according to the position of the position indicator, and drives the selected transmission coil so as to transmit the position detection signal. The receiving means sequentially selects a plurality of sensor coils and receives a signal from the position indicator. The position detecting means detects a position indicated by the position pointing device based on the signal received by the receiving means.

ADVANTAGE OF THE INVENTION According to this invention, in the position detection system of an electromagnetic coupling system, it becomes possible to make small the area which cannot detect the position of a position indicator. Further, it is possible to suppress a detection error.
Further, according to the present invention, it is possible to reduce a region in which the position of the position indicator cannot be detected in the electromagnetic coupling type position detecting device. Further, it is possible to suppress a detection error.

Hereinafter, a position detection system and a position detection device according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same parts are denoted by the same reference numerals.
FIG. 1 is a block diagram showing the configuration of the position detection system according to the first embodiment of the present invention.
The position detection system according to the first embodiment includes a position indicator 120 for indicating a position and a position detection device 100 for detecting the position of the position indicator 120.

The position indicator 120 is a device for indicating a position having at least one coil. A capacitor is connected to the coil, and a resonance circuit is configured by the coil and the capacitor.
The position detection device 100 includes a control unit 101, a transmission signal generation unit 102 for generating a position detection signal, a driver 103, a transmission selection unit 104 for selecting and driving a transmission coil for supplying a position detection signal, and a sensor serving as a sensor area. It includes a unit 105, a capacitor 106, a resistor 107, a reception selection unit 108, a reception amplifier 109, and a detection unit 110.
Note that the control unit 101 constitutes a signal transmission unit, a reception unit, and a detection unit, the transmission signal generation unit 102, the driver 103, and the transmission selection unit 104 constitute a signal transmission unit, and the reception selection unit 108 and the reception amplifier 109 The detecting unit 109 forms a receiving unit, and the detecting unit 109 forms a detecting unit.

The control unit 101 controls the entire position detection device 100 and controls the transmission signal generation unit 102, the driver 103, the transmission selection unit 104, the reception selection unit 108, the reception amplifier 109, and the detection unit 110.
The transmission signal generator 102 generates a position detection signal for detecting the position indicated by the position indicator 120 under the control of the controller 102. The driver 103 amplifies the position detection signal from the transmission signal generator 102 and outputs the amplified signal to the signal selector 104. The transmission selection unit 104 selects one of the plurality of transmission coils 111 and 112 under the control of the control unit 101, and supplies a position detection signal to the selected transmission coil to drive it.

In the first embodiment, two transmission coils 111 and 112 are provided as a plurality of transmission coils. The plurality of transmission coils 111 and 112 are juxtaposed so as not to overlap each other, and are arranged (concentrically) such that the centers of the respective transmission coils 111 and 112 are substantially at the same position. The outer (outer peripheral side of the sensor area 105) transmitting coil 111 is disposed outside the inner (central side of the sensor area 105) transmitting coil 112. Further, the outer transmission coil 111 is provided on the outer periphery of the sensor unit 105.
A single capacitor 106 is commonly connected to the plurality of transmission coils 111 and 112. The capacitor 106 forms a series resonance circuit with the transmission coils 111 and 112. That is, the capacitor 106 and the transmission coil 111 constitute a series resonance circuit, and the capacitor 106 and the transmission coil 112 constitute a series resonance circuit. The resonance frequency of each series resonance circuit is set to be equal to the frequency of a signal input to the transmission coils 111 and 112 via the transmission selection unit 104. As described above, since the transmission coils 111 and 112 and the capacitor 106 each constitute a series resonance circuit, it is possible to transmit a signal from the transmission coils 111 and 112 to the position indicator 120 with small power. Note that the resonance frequency of each series resonance circuit does not need to be completely equal to the frequency of the signal input to the transmission coils 111 and 112, and may be substantially equal (for example, within an error range of ± 20%).

The sensor unit 105 includes a plurality of transmitting coils 111 and 112 and a receiving unit 113 having a plurality of sensor coils. The receiving unit 113 includes a plurality of sensor coils (X direction sensor coils) 114 arranged in the X direction and a plurality of sensor coils (Y direction sensor coils) 115 arranged in the Y direction orthogonal to the X direction. Have been.
Note that at least one of the outer transmission coil 111 and the inner transmission coil 112 may be arranged outside the sensor coils 114 and 115. Also, neither the outer transmission coil 111 nor the inner transmission coil 112 may be configured to be disposed outside the sensor coils 114 and 115, that is, both are disposed so as to overlap the sensor coils 114 and 115. May be.

  Under the control of the control unit 101, the reception selection unit 108 sequentially selects and scans the plurality of sensor coils 114 and 115, and outputs a detection signal detected by the selected sensor coils 114 and 115 to the reception amplifier 109. The reception amplifier 109 amplifies the detection signal from the reception selection unit 108 and outputs the signal to the detection unit 110 under the control of the control unit 101. The detecting unit 110 calculates an X coordinate position and a Y coordinate position (XY coordinates) of the position indicator 120 based on the detection signal from the receiving amplifier 109, and outputs the X coordinate position and the Y coordinate position to the control unit 101. The control unit 101 controls the phase of the signal output by the transmission signal generation unit 102 according to the XY coordinate position of the position indicator 120 detected by the detection unit 110 and controls the transmission coil 111 by the transmission selection unit 104 as described later. , 112 and the like.

FIG. 2 is a timing chart showing the operation of the position detection system according to the first embodiment. In the first embodiment, the position of the position indicator 120 is detected by scanning the Y-direction sensor coil 115 after the scanning (scanning) of the X-direction sensor coil 114 is completed.
FIG. 3 is an explanatory diagram for explaining selection and driving operations of the transmission coils 111 and 112 in the position detection system according to the first embodiment. Although only the X-direction sensor coil 114 is shown in FIG. 3, the same selection and driving operation is performed for the Y-direction sensor coil 115.

  3, K1 to K10 are the X-direction sensor coils K1 to K10 shown in FIG. The signal 301 indicates the signal level of the alternating magnetic field emitted from the outer transmission coil 111 by driving the outer transmission coil 111. The signal 302 indicates the signal level of the alternating magnetic field emitted from the inner transmission coil 112 by driving the inner transmission coil 112.

As shown in FIG. 3, the sensor area is divided into three areas, area 1 to area 3. The first area 1 is an area where the output level of the inner transmission coil 112 is higher than the output level of the outer transmission coil 111 when the phase of the position detection signal is positive (first phase). The second area 2 is an area where the output level of the outer transmission coil 111 is higher than the output level of the inner transmission coil 112 when the phase of the position detection signal is positive (first phase). Further, the third region 3 is a region where the output level of the inner transmission coil 112 is larger than the output level of the outer transmission coil 111 when the phase of the position detection signal is the opposite phase (second phase) obtained by inverting the positive phase. It is.
FIGS. 4 to 6 are explanatory diagrams for explaining the selection switching operation of the transmission coils 111 and 112 in the position detection system according to the first embodiment.

Hereinafter, the operation of the first embodiment will be described in detail with reference to FIGS.
First, a detection operation (all scan operation) when the position detection device 100 does not know the position of the position indicator 120, such as when the power is turned on, will be described.
The position detection apparatus 100 will be briefly described below. Under the control of the control unit 101, the reception selecting unit 108 sequentially scans from the sensor coil K1 on one end side to the sensor coil K10 on the other end side, and performs position indication. The transmission coils 111 and 112 capable of supplying the largest position detection signal in the region where the device 120 is located are selectively driven in the normal phase or the negative phase to detect the position of the position indicator in the X direction. Similarly, in the Y direction, the transmission coil 111 that can sequentially scan the Y direction sensor coil 115 from one end to the other end and supply the largest position detection signal in the area where the position indicator 120 is located. , 112 are selectively driven in the normal phase or the negative phase, and the position of the position indicator 120 in the Y direction is detected. Thus, the XY coordinates of the position indicator 120 are detected.

Next, the position detection operation by the all scan will be described in detail. The transmission signal generation unit 102 outputs a position detection signal under the control of the control unit 101. The driver 103 amplifies and outputs the position detection signal under the control of the control unit 101. The transmission selection unit 104 selects one of the plurality of transmission coils 111 and 112 under the control of the control unit 101 and outputs the position detection signal from the driver 103 to the selected transmission coil. .
The selection operation of the transmission coils 111 and 112 will be described with reference to FIG. 3. When the sensor coils K1, K2, K9 and K10 in the area 3 are selected and a position indication signal from the position indicator 120 is received. Transmits a position detection signal from the inner transmission coil 112 to perform the position detection operation of the position indicator 120. In this case, under the control of the control unit 101, the transmission signal generation unit 102 transmits a signal having an opposite phase as the position detection signal.

When the position signals from the position indicator 120 are received by the sensor coils K3, K4, K7, and K8 in the area 2, the position detection operation of the position indicator 120 is performed by transmitting the position detection signal from the outer transmission coil 111. I do. In this case, under the control of the control unit 101, the transmission signal generation unit 102 transmits a signal having a positive phase as a position detection signal.
When the position signals from the position indicator 120 are received by the sensor coils K5,..., K6 in the area 1, the position detection signal is transmitted from the inner transmission coil 112 and the position of the position indicator 120 is Perform detection operation. In this case, under the control of the control unit 101, the transmission signal generation unit 102 transmits a signal having a positive phase as the position detection signal.

From the transmission coil (for example, the transmission coil 111) selected by the transmission selection unit 104, a position detection signal 201a is output as shown in FIG. The position indicator 120 receives the position detection signal 201a from the selected transmission coil 111 by electromagnetic coupling, and returns the position instruction signal 202a to the position detection device 100.
On the position detection device 100 side, the control unit 101 controls the reception selection unit 108 so that the reception selection unit 108 sequentially selects and scans the X-direction sensor coil 114 from one end to the other end (K1 to K10). 109 is controlled. As a result, first, the first X-direction sensor coil K1 receives the position indicating signal 202a. In this case, since the X-direction sensor coil K1 disposed in the area 3 receives the position instruction signal 202a, the transmission coil that outputs the position instruction signal 202a is the inner transmission coil 112. .

The position instruction signal received by the X-direction sensor coil K1 is output to the reception amplifier 109 via the reception selection unit 108 as an X-direction detection signal. The X direction detection signal is amplified by the reception amplifier 109 and then output to the detection unit 110. The detection unit 110 temporarily stores the level of the detection signal in a memory (not shown) serving as storage means provided inside the detection unit 110.
The above operation is performed four times for the X-direction sensor coil K1 and stored in the memory in the detection unit 110. The detection unit 110 stores the average value of the four data stored in the memory in the detection unit 110 as the X-direction detection signal level of the X-direction sensor coil K1 in the memory.

By sequentially performing the operation from the sensor coil K1 to the sensor coil K10 for all the X-direction sensor coils 114, the detection unit 110 acquires the detection signal levels (X-direction detection signal levels) of all the X-direction sensor coils K1 to K10. And store it in the memory. As described above, the transmission coil 111 or the transmission coil 112 that can supply the maximum position detection signal to the position indicator 120 is selected according to the regions 1 to 3 to which the position indicator 120 belongs, and The transmission coil 111 or the transmission coil 112 selected so that the phase of the detection signal does not reverse is driven, and a signal of the normal phase is always transmitted to the position indicator 120 as a position detection signal.
The detection unit 110 selects the top three points among the detection signal levels of all the X-direction sensor coils K1 to K10, and calculates the maximum level point by parabolic approximation using the three detection levels. The coordinates of the maximum level point correspond to the X coordinate of the position indicator 120.

Next, the position detection device 100 sequentially performs the same operation as described above for all the Y-axis direction sensor coils 115.
That is, the control unit 101 sequentially selects and scans all the Y-direction sensor coils 115 from one end (coil L1) to the other end (coil L10). The detection unit 110 calculates the Y coordinate of the position indicator 120 in the same manner as performed for the X-direction sensor coil 114. The sensor area is also divided into three areas in the Y direction similarly to FIG. 3, and the transmission coils 111 and 112 are selectively driven according to the areas 1 to 3 to which the selected X direction sensor coil 114 belongs. Similarly, the transmission selecting unit 104 selects the transmission coil 111 or the transmission coil 112 according to the area to which the Y-direction sensor coil 115 to be selected belongs, and the transmission coil 111 selected so that the phase of the position detection signal does not reverse. Alternatively, the transmission coil 112 is driven, and a positive-phase signal is always transmitted to the position indicator 120 as a position detection signal.

As described above, the detection unit 110 detects the X coordinate and the Y coordinate (XY coordinate) of the position indicator 120.
The detection unit 110 outputs the data of the XY coordinates of the position indicator 120 detected in this way to the control unit 101.
Once detecting the position of the position indicator 120, the control unit 101 determines the position of the position indicator 120 according to the relative positional relationship between the position indicator 120 and the plurality of transmission coils 111 and 112, as described later. In the area where is located, the transmission selection unit 104 is controlled to select one of the plurality of transmission coils 111 and 112 so that the maximum position detection signal can be supplied to the position indicator 120, and the position The transmission signal generation unit 102 is controlled so that the position of the position detection signal supplied to the indicator 120 always becomes the positive phase (does not reverse) and the selected transmission coil is driven in the normal phase or the reverse phase.
At the same time, the control unit 101 transmits a predetermined number of sensor coils 114 and 115 (for example, a sensor coil and a position indicator in an area where the position The position indicator 120 is detected by sequentially selecting and scanning (sector scan) the plurality of sensor coils in other regions arranged adjacent to the region where the position 120 is located.

Next, an operation in the case where a plurality of transmission coils 111 and 112 are selected in accordance with the relative positional relationship between the position indicator 120 and the transmission coils 111 and 112 to drive them in positive or negative phase and to perform sector scan will be described. . It should be noted that, depending on whether the position indicator 120 is located inside or outside the transmission coil to be selectively driven, the phase of the signal for driving the transmission coil is reversed, and the position indicator 120 always has the same phase. The detection signal is transmitted.
In FIG. 3, when a transmission coil is selected from a plurality of transmission coils 111 and 112, a transmission coil capable of transmitting the strongest signal to position indicator 120 in an area where position indicator 120 is located. Select
That is, when the position indicator 120 is present in the area 1, the position detection signal is transmitted from the inner transmission coil 112 to perform the position detection operation of the position indicator 120. In this case, since the position indicator 120 is located inside the selected transmission coil 112 (the center side of the sensor area 105), the phase of the position detection signal output from the transmission signal generation unit 102 to the transmission coil 112 side. Is positive phase.

  FIG. 4 shows a driving operation of the transmission coils 111 and 112 when the position indicator 120 is located in the area 1. As shown in FIG. 4, when the position indicator 120 exists in the area 1, the outer transmission coil 111 is not driven, and only the inner transmission coil 112 is driven in the normal phase. A current in the direction of the arrow (positive phase) is caused to flow through the inner transmission coil 112 to generate a positive-phase position detection signal with an alternating magnetic field. The position indicator 120 is excited by a positive-phase position detection signal by electromagnetic coupling.

When the position indicator 120 is present in the area 2, a position detection signal is transmitted from the outer transmission coil 111 to perform the position detection operation of the position indicator 120. Also in this case, since the position indicator 120 is located inside the selected transmission coil 111, the phase of the position detection signal output by the transmission signal generation unit 102 to the transmission coil 111 is positive.
FIG. 5 shows a driving operation of the transmission coils 111 and 112 when the position indicator 120 is located in the area 2. As shown in FIG. 5, when the position indicator 120 exists in the area 2, the inner transmission coil 112 is not driven, and only the outer transmission coil 111 is driven in the normal phase. A current in the direction of the arrow (positive phase) is caused to flow through the outer transmission coil 111 to generate a positive-phase position detection signal with an alternating magnetic field. The position indicator 120 is excited by a positive-phase position detection signal by electromagnetic coupling.

When the position indicator 120 exists in the area 3, the position detection signal is transmitted from the inner transmission coil 112 to perform the position detection operation of the position indicator 120. In this case, since the position indicator 120 is located outside the selected transmission coil 112 (around the sensor area 115), the phase of the position detection signal output from the transmission signal generation unit 102 to the transmission coil 111 side is selected. Are in opposite phases.
FIG. 6 shows a driving operation of the transmission coils 111 and 112 when the position indicator 120 exists in the area 3. As shown in FIG. 6, when the position indicator 120 exists in the area 3, the outer transmission coil 111 is not driven, and only the inner transmission coil 112 is driven in the opposite phase. A current in the direction indicated by the arrow (opposite phase) is caused to flow through the inner transmitting coil 112 to generate a positive-phase position detection signal with an alternating magnetic field. Also in this case, the position indicator 120 is excited by a positive-phase signal by electromagnetic coupling.

As described above, the signal transmission unit divides the sensor area 105 in which the plurality of transmission coils 111 and 112 are disposed into a plurality of areas 1 to 3 and, in the area where the position indicator 120 is located, A position detection signal is supplied to the position indicator 120 by selecting and driving a transmission coil capable of supplying the largest position detection signal to the position indicator 120.
Further, depending on whether the position indicator 120 is located inside the driving transmission coil (the center side of the sensor area) or outside the driving coil (the peripheral side of the sensor area), the transmission coil is determined. The phase of the position detection signal to be driven is reversed. Therefore, the position indicator 120 is always excited by the in-phase (positive-phase) signal.
Once the coil of the position pointer 120 is excited, even if the excitation is stopped, the induced voltage generated gradually decreases, but not all disappears by the next excitation. There is a residual induced voltage. When detecting the position of the position detecting device 120, the calculation is performed in consideration of the residual induced voltage. However, if the phase of the position indicator 120 is reversed, the residual induced voltage is canceled. become. As a result, the position pointing signal does not have the original strength, and as a result, an error occurs in the detection position of the position pointing device 120. As in the present embodiment, by always making the position detection signals transmitted from the transmission coil have the same polarity (in phase), it is possible to suppress a position detection error caused by the influence of the residual induced voltage.

As described above, the transmission coils 111 and 112 are selectively driven, and in synchronization with this, the control unit 101 controls the predetermined number of sensor coils 114 and 115 disposed in the area where the position indicator 120 is located and the surrounding area. (E.g., a sensor coil in an area where the position indicator 120 is located and a plurality of sensor coils in other areas disposed adjacent to the area where the position indicator 120 is located) are sequentially selectively scanned (sector scan). , The position of the position indicator 120 is detected.
Thereafter, the position of the position indicator 120 is detected by repeating the above operation.

FIG. 7 is a block diagram showing the configuration of the position detection system according to the second embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals.
The position detection system according to the second embodiment includes a position indicator 120 for indicating a position and a position detection device 700 for detecting the position of the position indicator 120.
The position indicator 120 is a device for indicating a position having at least one coil, as in the first embodiment, and a capacitor is connected to the coil. A resonance circuit is configured.

The position detection device 700 includes a control unit 101, a transmission signal generation unit 102 for generating a position detection signal, a driver 103, a transmission selection unit 104 for selecting a transmission coil for supplying a position detection signal, a sensor unit 105, a capacitor 106, It includes a resistor 107, a reception selection unit 108, a first reception amplifier 701, a first detection unit 702, a second reception amplifier 703, and a second detection unit 704.
Note that the control unit 101 constitutes a signal transmission unit, a reception unit, and a detection unit, and the transmission signal generation unit 102, the driver 103, and the transmission selection unit 104 constitute a signal transmission unit, and the reception selection unit 108, the reception amplifier 701, Reference numeral 703 constitutes a receiving unit, and the detecting units 702 and 704 constitute a detecting unit.
The control unit 101 controls the entire position detection device 700, and also includes a transmission signal generation unit 102, a driver 103, a transmission selection unit 104, a reception selection unit 108, a first reception amplifier 701, a first detection unit 702, and a second reception amplifier. 703 and the second detection unit 704 are controlled.

The transmission signal generator 102 generates a position detection signal for detecting the position indicated by the position indicator 120 under the control of the controller 101. The driver 103 amplifies the position detection signal from the transmission signal generator 102 and outputs the amplified signal to the signal selector 104. The transmission selection unit 104 selects one of the transmission coils 111 and 112 under the control of the control unit 101 and supplies a position detection signal.
In the second embodiment, as in the first embodiment, two transmission coils 111 and 112 are provided as a plurality of transmission coils. The plurality of transmission coils 111 and 112 are juxtaposed so as not to overlap each other, and are arranged (concentrically) such that the centers of the respective transmission coils 111 and 112 are substantially at the same position. The outer transmission coil 111 is provided outside the inner transmission coil 112. Further, the outer transmission coil 111 is provided on the outer periphery of the sensor unit 105.

The sensor unit 105 includes a plurality of transmitting coils 111 and 112 and a receiving unit 113 having a plurality of sensor coils. The receiving unit 113 includes a plurality of sensor coils (X direction sensor coils) 114 arranged in the X direction and a plurality of sensor coils (Y direction sensor coils) 115 arranged in the Y direction orthogonal to the X direction. Have been.
Note that at least one of the outer transmission coil 111 and the inner transmission coil 112 may be arranged outside the sensor coils 114 and 115. Also, neither the outer transmission coil 111 nor the inner transmission coil 112 may be configured to be disposed outside the sensor coils 114 and 115, that is, both are disposed so as to overlap the sensor coils 114 and 115. May be.

Under the control of the control unit 101, the reception selection unit 108 sequentially selects and scans both the X-direction sensor coil 114 and the Y-direction sensor coil 115 from the plurality of sensor coils 114 and 115 simultaneously, and scans the selected X-direction sensor. The detection signal in the X direction detected by the coil 114 is output to the reception amplifier 701, and the detection signal in the Y direction detected by the selected Y direction sensor coil 115 is output to the reception amplifier 703.
The reception amplifier 701 amplifies the X-direction detection signal from the reception selection unit 108 and outputs the signal to the detection unit 702 under the control of the control unit 101. The detecting unit 702 calculates the X coordinate position of the position indicator 120 based on the X direction detection signal from the receiving amplifier 701, and outputs the X coordinate position to the control unit 101.

Also, under the control of the control unit 101, the reception amplifier 703 amplifies the Y direction detection signal from the reception selection unit 108 and outputs the signal to the detection unit 704. The detecting unit 704 calculates the Y coordinate position of the position indicator 120 based on the Y direction detection signal from the receiving amplifier 703, and outputs it to the control unit 101.
The control unit 101 controls the phase of the signal output from the transmission signal generation unit 102 and selects transmission according to the X coordinate position and the Y coordinate position of the position indicator 120 detected by the detection units 702 and 704, as described later. Various controls such as selection control of the transmission coils 111 and 112 by the unit 104 are performed.

FIG. 8 is a timing chart showing the operation of the position detection system according to the second embodiment. In the second embodiment, the position of the position indicator 120 is detected by performing scanning of the X-direction sensor coil 114 and scanning of the Y-direction sensor coil 115 in parallel.
Hereinafter, the operation of the second embodiment will be described in detail with reference to FIGS. Note that the selection and driving operation of the transmission coils 111 and 112 in the second embodiment are the same as those in the first embodiment, and thus description thereof will be omitted.

First, a detection operation when the position detection device 700 does not grasp the position of the position indicator 120, such as when the power is turned on, will be described.
An outline of the operation in this case is as follows. Under the control of the control unit 101, the position detection device 700 selectively drives the transmission coils 111 and 112 as shown in FIG. The X-direction scanning is performed by sequentially scanning all the X-direction sensor coils 114, and the Y-direction scanning is performed by sequentially scanning all the Y-direction sensor coils 115 in parallel with the X-direction scanning. (Scan) to detect the position of the position indicator 120.

  Next, the position detection operation by the all scan will be described in detail. The transmission signal generation unit 102 outputs a position detection signal under the control of the control unit 101. The driver 103 amplifies and outputs the position detection signal under the control of the control unit 101. The transmission selection unit 104 selects one of the plurality of transmission coils 111 and 112 under the control of the control unit 101 and outputs the position detection signal from the driver 103 to the selected transmission coil. . The operation of selecting the plurality of transmission coils 111 and 112 is performed in the same manner as in the first embodiment.

From the selected transmission coil (for example, the transmission coil 111), a position detection signal 201a is output as shown in FIG. The position indicator 120 receives the position detection signal 201a from the selected transmission coil 111 by electromagnetic coupling, and returns a position instruction signal 202a to the position detection device 700.
On the position detection device 700 side, the control unit 101 causes the reception selection unit 108 to sequentially select and scan the X-direction sensor coil 114 from one end (coil K1) to the other end (coil K10), and simultaneously, The reception selection unit 108 is controlled so that the direction sensor coil 115 is sequentially selected from one end (coil L1) to the other end (coil L10) for scanning. Thus, the first X-direction sensor coil K1 receives the position indicating signal 202a, and the first Y-direction sensor coil L1 receives the position indicating signal 202a.

The position indication signal received by the X-direction sensor coil K1 is output to the reception amplifier 701 via the reception selection unit 108 as an X-direction detection signal. The X direction detection signal is output to the detection unit 702 after being amplified by the reception amplifier 701. The detection unit 702 temporarily stores the level of the detection signal in a memory (not shown) serving as storage means provided inside the detection unit 702.
The above operation is performed four times for the X-direction sensor coil K1 and stored in the memory in the detection unit 702. The detection unit 702 stores the average value of the four data stored in the memory in the detection unit 702 as the X-direction detection signal level of the X-direction sensor coil K1 in the memory.

At the same time, the position indication signal received by the Y-direction sensor coil L1 is output to the reception amplifier 703 via the reception selection unit 108 as a Y-direction detection signal. The Y direction detection signal is output to the detection unit 704 after being amplified by the reception amplifier 703. The detection unit 704 temporarily stores the level of the detection signal in a memory (not shown) serving as storage means provided inside the detection unit 704.
The above operation is performed four times for the Y-direction sensor coil L1 and stored in the memory in the detection unit 704. The detection unit 704 stores the average value of the four data stored in the memory in the detection unit 704 as the Y-direction detection signal level of the Y-direction sensor coil L1 in the memory.

  By sequentially performing the above operation for all the X-direction sensor coils 114 and all the Y-direction sensor coils 115, the detection unit 702 obtains detection signal levels (X-direction detection signal levels) of all the X-direction sensor coils K1 to K10, and And the detection unit 704 obtains the detection signal levels (Y-direction detection signal levels) of all the Y-direction sensor coils L1 to L10 and stores them in the memory. As described above, the transmission coil 111 or the transmission coil 112 is selected according to the regions 1 to 3 to which the selected X-direction sensor coil 114 and Y-direction sensor coil 115 belong, and the in-phase position detection signal is always selected. Is transmitted to the position indicator 120, the selected transmission coil is driven in the normal phase or the negative phase.

  Next, using the data of the X-direction detection levels stored in the memory, the detection unit 702 selects the top three points among the detection signal levels of all the X-direction sensor coils K1 to K10, and sets the detection levels of the three points. And the maximum level point is calculated by parabolic approximation. The coordinates of the maximum level point correspond to the X coordinate of the position indicator 120. At the same time, the detection unit 704 selects the upper three points among the detection signal levels of all the Y-direction sensor coils L1 to L10 using the data of the Y-direction detection levels stored in the memory, and changes the detection levels of the three points. And the maximum level point is calculated by parabolic approximation. The coordinates of the maximum level point correspond to the Y coordinates of the position indicator 120. As described above, the detection units 702 and 704 detect the X coordinate and the Y coordinate (XY coordinate) of the position indicator 120.

  The detection units 702 and 704 respectively output the X coordinate data and the Y coordinate data of the position indicator 120 detected in this way to the control unit 101. Once the position of the position indicator 120 is detected, the control unit 101 responds to the relative positional relationship between the position indicator 120 and the plurality of transmission coils 111 and 112 in the same manner as in the first embodiment. The transmission selection unit 104 selects one of the plurality of transmission coils 111 and 112 so that the maximum position detection signal can be supplied to the position indicator 120 in the area where the position indicator 120 is located. And the transmission signal generator 102 is controlled so as to always generate a positive-phase (in-phase) position detection signal from the selected transmission coil.

At the same time, the control unit 101 determines a predetermined number of sensor coils 114 and 115 (for example, a sensor coil and a position indicator in an area where the position indicator 120 is located) disposed in an area where the position indicator 120 is located and a peripheral area thereof. The position indicator 120 is detected by sequentially selecting and scanning (sector scan) the plurality of sensor coils in other regions arranged adjacent to the region where the position 120 is located.
As described above, also in the second embodiment, the area where the position of the position indicator 120 cannot be detected can be reduced. In addition, it becomes possible to always excite the position indicator 120 with an in-phase signal. Therefore, it is possible to suppress an error in the detection position of the position indicator 120 due to the influence of the residual induced voltage generated in the position indicator 120.
Further, in the second embodiment, since the scanning of the X-direction sensor coil 114 and the scanning of the Y-direction sensor coil 115 are performed in parallel, the sensor coil is compared with the first embodiment. Can be doubled, and the position can be detected in a short time.

Next, a third embodiment of the present invention will be described. FIG. 9 is an explanatory diagram for explaining an operation of the position detection system according to the third embodiment of the present invention, showing a selective driving operation of the transmission coil, and is an explanatory diagram corresponding to FIG.
Although a block diagram of the position detection system according to the third embodiment is omitted, the position detection device 100 according to the first embodiment has two transmission coils 111 and 112, whereas The position detecting device according to the third embodiment is different in that it has three transmitting coils 901, 902, and 903, but other configurations are the same as those in FIG. Note that the position detecting device according to the third embodiment uses the receiving amplifier and the detecting unit for the X direction and the receiving amplifier and the detecting unit for the Y direction in the same manner as the second embodiment. You may comprise so that a direction detection signal and a Y direction detection signal may be detected in parallel.

Hereinafter, the operation of the third embodiment will be described with reference to FIG. 9 and FIG.
In FIG. 9, C1 to C18 are X-direction sensor coils. The signal 906 indicates the signal level of the alternating magnetic field emitted from the outer transmission coil 901 when the position detection signal is supplied to the outer transmission coil 901. The signal 905 indicates the signal level of the alternating magnetic field emitted from the center transmission coil 902 when the position detection signal is supplied to the center transmission coil 902. A signal 904 indicates a signal level of an alternating magnetic field emitted from the inner transmission coil 901 when a position detection signal is supplied to the inner transmission coil 903.

  As shown in FIG. 9, the sensor area is divided into a plurality of areas (five in this embodiment), and in area 1, the position detection signal for driving the transmission coil has a positive phase (first phase). In this case, the output level of the inner transmission coil 903 is larger than the output levels of the outer transmission coil 901 and the center transmission coil 902. Region 2 is a region where the output level of the center side transmission coil 902 is higher than the output level of the outer side transmission coil 901 and the inner side transmission coil 903 when the position detection signal for driving the transmission coil is in the positive phase. Region 3 is a region where the output level of the outer transmission coil 901 is higher than the output level of the center transmission coil 902 or the inner transmission coil 903 when the position detection signal for driving the transmission coil is in the positive phase. In the area 4, when the position detection signal for driving the transmission coil is in the opposite phase (second phase), the output level of the center transmission coil 902 is higher than the output level of the outer transmission coil 901 or the inner transmission coil 903. Area. The area 5 is an area where the output level of the outer transmission coil 901 is higher than the output levels of the center transmission coil 902 and the inner transmission coil 903 when the position detection signals for driving the transmission coils are in opposite phases.

  The scanning of the X-direction sensor coils C1 to C18 and the Y-direction sensor coil (not shown) during the all scan, the selective driving of the transmitting coils 901 to 902, and the normal / reverse phase driving are the same as in the first and second embodiments. Done in That is, under the control of the control unit, the transmission coils 901 to 903 arranged corresponding to the X-direction sensor coil and the Y-direction sensor coil selected by the reception selection unit are always supplied to the position indicator with the same phase detection signal. Is selectively driven in the positive or negative phase so that is supplied in an alternating magnetic field, and in synchronization with this, the reception selecting unit performs scanning in the X direction by sequentially scanning all the X direction sensor coils. , Scanning in the Y direction is performed by sequentially scanning all the Y direction sensor coils to detect the position of the position indicator.

When a transmission coil is selected from a plurality of transmission coils 901 to 903 when performing a sector scan, the control unit determines a position indicator based on a relative positional relationship between the position indicator and the transmission coils 901 to 903. Controlling the transmission selection unit so as to select a transmission coil capable of transmitting the strongest signal to the position indicator in the area where the position indicator is located, and so that the in-phase signal is always supplied to the position indicator. Of the transmission signal generating unit is controlled so as to drive in the normal or reverse phase.
Further, depending on whether the position indicator is located inside or outside the selected transmission coil, the phase of the signal for driving the transmission coil is reversed, and the position indicator always outputs the same phase detection signal to the position indicator. Are transmitted in an alternating magnetic field.

For example, when the position indicator is present in the area 5, a position detection signal is transmitted from the outer transmission coil 901 to perform the position detection operation of the position indicator 120. In this case, since the position indicator is located outside the transmission coil 901, a position detection signal having an opposite phase is supplied to the transmission coil 901 from the transmission signal generation unit.
At the same time, the control unit controls a predetermined number of sensor coils (for example, the sensor coils C1 and C2 and the position indicator A plurality of sensor coils C3 and C4 in another area (left area 4) disposed adjacent to the left area 5 where 120 is located are sequentially selected and scanned (sector scan) to determine the position of the position indicator. Perform detection.

When the position indicator is present in the left area 4, a position detection signal is transmitted from the center transmission coil 902 to perform the position detection operation of the position indicator. Also in this case, since the position indicator is located outside the transmission coil 902, a position detection signal having an opposite phase is supplied to the transmission coil 902 from the transmission signal generator. The reception of the signal from the position detector is performed by the sensor coils C3 and C4 existing in the left area 4 and a plurality of sensor coils C2 and C5 arranged around the left area 4.
When the position indicator is present in the left region 3, a position detection signal is transmitted from the outer transmission coil 901 to perform a position detection operation of the position indicator. In this case, since the position indicator is located inside the transmission coil 901, a positive-phase position detection signal is supplied from the transmission signal generator to the transmission coil 901. The reception of the signal from the position detector is performed by the sensor coils C5 and C6 existing in the left area 3 and the sensor coils C4 and C7 arranged around the left area 3.
When the position indicator is present in the left area 2, a position detection signal is transmitted from the center transmission coil 902 to perform the position detection operation of the position indicator. Also in this case, since the position indicator is located inside the transmission coil 902, a positive-phase position detection signal is supplied to the transmission coil 902 from the transmission signal generator. The reception of the signal from the position detector is performed by the sensor coils C7 and C8 disposed in the left area 2 and the plurality of sensor coils C6 and C9 disposed around the left area 2.

When the position indicator is present in the area 1, the position detection signal is transmitted from the inner transmission coil 903 to perform the position detection operation of the position indicator. Also in this case, since the position indicator is located inside the transmission coil 903, a positive-phase position detection signal is supplied to the transmission coil 902 from the transmission signal generator. The reception of the signal from the position detector is performed by the sensor coils C9,..., C10 existing in the area 1 and the plurality of sensor coils C8, C11 arranged around the area 1.
This makes it possible to reduce the area where the position of the position indicator cannot be detected. Further, by performing the position detection by always exciting the position indicator with the in-phase signal, it is possible to suppress the error of the detected position caused by the influence of the residual induced voltage.

  As described above, the position detection system according to the embodiment of the present invention includes a position indicator having at least one coil for indicating a position, and transmission and reception of signals between the position indicator by electromagnetic coupling. And a position detecting device having a position detecting device for detecting the position indicated by the position pointing device 120 by performing the above-described operations. The position detecting devices 100 and 700 are provided concentrically and transmit a position detection signal to the position pointing device 120. A plurality of transmission coils 111, 112, 901 to 903 for transmitting, a plurality of sensor coils K1 to K10, L1 to L10, C1 to C18 for receiving signals from the position indicator 120, and a position indicator 120, any one of the plurality of transmission coils 111, 112, 901 to 903 is selected, and the selection is made so as to transmit the position detection signal. The signal transmission means (the control unit 101, the transmission signal generation unit 102, the driver 103, the transmission selection unit 104) for driving the transmission coil thus formed, and the plurality of sensor coils K1 to K10, L1 to L10, C1 to C18, and the like are sequentially arranged. Receiving means (control section 101, reception selecting section 108, receiving amplifiers 109, 701, 703) for selecting and receiving a signal from the position pointing device, and receiving means for the position pointing device based on the signal received by the receiving means. It is configured to include a position detecting means (control unit 101, detecting units 110, 702, 704) for detecting the designated position. Therefore, in the position detection system of the electromagnetic coupling type, it is possible to reduce a region where the position of the position indicator cannot be detected.

Further, the signal transmitting means selects and drives a transmission coil capable of supplying the largest position detection signal to the position indicator 120 in an area where the position indicator 120 is located, so that the position indicator 120 On the other hand, since the configuration is such that the position detection signal is supplied by an alternating magnetic field, a large signal can be used, noise resistance is excellent, and position detection can be performed with high quality.
In addition, the signal transmission unit reverses the phase of the position detection signal supplied to the position indicator based on the position of the position indicator detected by the position detection unit and the relative positional relationship of the selected transmission coil. It is configured to drive the selected transmission coil so as not to perform it. For example, the signal transmitting means may perform the selection depending on whether the position indicator is located inside (the center side of the sensor area) and outside (the outer peripheral side of the sensor area) the selected transmission coil. Since the phase of the signal for driving the transmission coil is inverted and the position detection signal having the same phase is always transmitted to the position indicator, the position indication is affected by the residual induced voltage generated in the position indicator 120. It is possible to suppress an error occurring at the detection position of the detector 120.

  In addition, the position detection devices 100 and 700 according to the present embodiment include, in particular, a plurality of transmission coils 111, 112, 901 to 903 that are arranged concentrically and transmit a position detection signal to the position indicator 120. , A plurality of sensor coils K1 to K10, L1 to L10, C1 to C18, etc. for receiving signals from the position indicator 120, and the plurality of transmission coils K1 to K10, L1 according to the position of the position indicator 120. To L10, C1 to C18, and the like, and a signal transmission unit that drives the selected transmission coil so as to transmit the position detection signal, and sequentially selects the plurality of sensor coils. A receiving unit that receives a signal from the position indicator; and a position detecting unit that detects a position indicated by the position indicator based on the signal received by the receiving unit. Because you are, it is possible to reduce the undetectable region the position of the position indicator.

Further, the signal transmitting means divides a sensor area in which a plurality of transmitting coils are arranged into a plurality of areas, and in the area where the position indicator 120 is located, the largest position detection signal with respect to the position indicator 120. By selecting and driving a transmission coil capable of supplying the position detection signal, the position detection signal is supplied to the position indicator 120 by electromagnetic coupling, so that a large position detection signal can be used. It is excellent in noise resistance and has an effect that position detection can be performed with high quality.
In addition, the plurality of transmission coils 111 and 112 are transmission coils dedicated to transmitting position detection signals, and the sensor coils 114 and 115 are sensor coils dedicated to reception of position indication signals, so that the sensor coils also serve as transmission coils. Compared with the method, the number of transmission coils can be reduced, and the circuit size of the transmission selection unit can be reduced.

In the above-described embodiment, the plurality of transmission coils are arranged concentrically so as to simplify the calculation process of the position of the position indicator, but it is not always necessary to arrange the transmission coils concentrically, and they overlap each other. It is possible to arrange a plurality of transmission coils in various modes, such as disposing a plurality of transmission coils.
Further, in the above-described embodiment, the example in which the number of the transmission coils is two and the example in which the number of the transmission coils is three have been described.
Further, the transmission coils 111, 112, 901 to 903 need not always be arranged outside the sensor coils 114, 115.
Further, in the present embodiment, the position detection signal for exciting the position indicator 120 is driven so that the phase becomes the same phase. However, when it is not necessary to make the phase identical, it is not necessary to reverse the phase and make the phase the same. Absent.

  An input device such as a CAD (Computer Aided Design), a computer, a personal digital assistant (PDA), a mobile phone, a PHS (Personal Handyphone System), and a detection system that detects three-dimensional information such as the position and orientation of the input device in a three-dimensional space. And so on.

FIG. 1 is a block diagram of a position detection system according to a first embodiment of the present invention. FIG. 2 is a timing chart of the position detection system according to the first embodiment of the present invention. FIG. 3 is an explanatory diagram illustrating an operation of the position detection system according to the first embodiment of the present invention. It is a schematic diagram for explaining operation of the position detection system according to the first exemplary embodiment of the present invention. It is a schematic diagram for explaining operation of the position detection system according to the first exemplary embodiment of the present invention. It is a schematic diagram for explaining operation of the position detection system according to the first exemplary embodiment of the present invention. It is a block diagram of a position detection system concerning a 2nd embodiment of the present invention. FIG. 9 is a timing chart of the position detection system according to the second embodiment of the present invention. It is an operation explanatory view of the position detection system according to the third embodiment of the present invention. FIG. 9 is a schematic diagram for explaining an operation of a conventional position detection system.

Explanation of reference numerals

100, 700 ··· Position detection device 120 ··· Position indicator 101 ··· Control unit 102 that constitutes signal transmission means, reception means and detection means ··· Transmission signal generation unit 103 that constitutes signal transmission means Driver 104 constituting signal transmitting means Transmission selecting section 105 constituting signal transmitting means Sensor section 106 Capacitor 108 Receiving selecting sections 109, 701, 703 constituting receiving means ... Receiving amplifiers 110, 702, 704 forming a receiving unit. Detecting units 111, 112 forming a detecting unit.

Claims (20)

A position indicator having at least one coil for indicating a position, and a position detection device for detecting a position indicated by the position indicator by transmitting and receiving signals between the position indicator by electromagnetic coupling. In the position detection system having
The position detection device includes a plurality of transmission coils for transmitting a position detection signal to the position indicator, a plurality of sensor coils for receiving a signal from the position indicator, and a position of the position indicator. And selecting one of the plurality of transmission coils according to the signal transmission means for driving the selected transmission coil so as to transmit the position detection signal, and sequentially selecting the plurality of sensor coils. Receiving means for receiving a signal from the position pointing device, and position detecting means for detecting a pointing position of the position pointing device based on the signal received by the receiving means. system. The position detection system according to claim 1, wherein the plurality of transmission coils are arranged concentrically. The signal transmitting unit divides a sensor area in which the plurality of transmission coils are arranged into a plurality of areas, and outputs a largest position detection signal to the position indicator in the area where the position indicator is located. The position detection system according to claim 1 or 2, wherein the position detection signal is supplied by selecting and driving a supply coil that can be supplied. The position detection system according to claim 1, further comprising a capacitor that forms a series resonance circuit together with each of the transmission coils. The position detection system according to claim 4, wherein the capacitor is a single capacitor commonly connected to the plurality of transmission coils. The signal transmission unit is configured to prevent the phase of the position detection signal supplied to the position indicator from being reversed based on the position of the position indicator detected by the position detection unit and the relative positional relationship of the selected transmission coil. 6. The position detection system according to claim 1, wherein the selected transmission coil is driven. The signal transmission means reverses the phase of a signal for driving the transmission coil depending on whether the position indicator is positioned inside or outside the transmission coil, and the position indicator always has the same phase as the position indicator. 7. The position detection system according to claim 6, wherein a detection signal is transmitted. The said plurality of transmission coils are comprised by the 1st transmission coil and the 2nd transmission coil arrange | positioned concentrically outside the said 1st transmission coil, The Claims 1 thru | or 7 characterized by the above-mentioned. The position detection system according to any one of the above. When the position detection signal is transmitted at a first phase in a sensor area capable of detecting the position of the position indicator, the position of the first transmission coil is higher than that of the second transmission coil. A first area in which a signal can be transmitted, the second transmission coil can transmit a position detection signal at a higher level than the first transmission coil when the position detection signal is transmitted in the first phase. A second area, the position detection signal having a level higher than that of the second transmission coil when the first transmission coil transmits the position detection signal at a second phase obtained by inverting the first phase. Is divided into a third area that can be transmitted,
The signal transmitting means transmits the position detection signal at the first phase from the first transmission coil when the position indicator is located in the first area, and the position indicator is When the position indicator is located in the second region, the position detection signal is transmitted at the first phase from the second transmission coil, and when the position indicator is located in the third region, the first position detection signal is transmitted. The position detection system according to claim 8, wherein the position detection signal is transmitted from the transmission coil at the second phase. When the position indicator is located in the first area, the receiving means sequentially selects a plurality of predetermined sensor coils disposed in the first area and the periphery thereof and outputs a signal from the position indicator. Receiving, when the position indicator is located in the second area, sequentially receiving a signal from the position indicator by sequentially selecting a plurality of predetermined sensor coils disposed in the second area and the periphery thereof; When the position indicator is located in the third area, sequentially selecting a plurality of predetermined sensor coils disposed in the third area and the periphery thereof and receiving a signal from the position indicator. The position detection system according to claim 9, wherein: In a position detection device that detects an indicated position of the position indicator by performing transmission and reception of signals by electromagnetic coupling between the position indicator having at least one coil and indicating a position,
A plurality of transmission coils for transmitting a position detection signal to the position indicator, a plurality of sensor coils for receiving a signal from the position indicator, and the plurality of sensor coils according to the position of the position indicator A signal transmission unit that selects one of the transmission coils and drives the selected transmission coil so as to transmit the position detection signal, and sequentially selects the plurality of sensor coils from the position indicator. A position detecting device comprising: receiving means for receiving a signal of the position indicator; and position detecting means for detecting a position indicated by the position indicator based on the signal received by the receiving means. The position detection device according to claim 11, wherein the plurality of transmission coils are arranged concentrically. The signal transmitting unit divides a sensor area in which the plurality of transmission coils are arranged into a plurality of areas, and outputs a largest position detection signal to the position indicator in the area where the position indicator is located. 13. The position detection device according to claim 11, wherein the position detection signal is supplied by selecting and driving a supply coil that can be supplied. 14. The position detecting device according to claim 11, further comprising a capacitor that forms a series resonance circuit together with each of the transmission coils. The position detection device according to claim 14, wherein the capacitor is a single capacitor commonly connected to the plurality of transmission coils. The signal transmission unit is configured to prevent the phase of the position detection signal supplied to the position indicator from being reversed based on the position of the position indicator detected by the position detection unit and the relative positional relationship of the selected transmission coil. 16. The position detecting device according to claim 11, wherein the selected transmitting coil is driven. The signal transmission means reverses the phase of a signal for driving the transmission coil depending on whether the position indicator is positioned inside or outside the transmission coil, and the position indicator always has the same phase as the position indicator. 17. The position detecting device according to claim 16, wherein a detecting signal is transmitted. 18. The transmission coil according to claim 9, wherein the plurality of transmission coils include a first transmission coil and a second transmission coil disposed concentrically outside the first transmission coil. The position detecting device according to any one of the above. When the position detection signal is transmitted at a first phase in a sensor area capable of detecting the position of the position indicator, the position of the first transmission coil is higher than that of the second transmission coil. A first area in which a signal can be transmitted, the second transmission coil can transmit a position detection signal at a higher level than the first transmission coil when the position detection signal is transmitted in the first phase. A second area, the position detection signal having a level higher than that of the second transmission coil when the first transmission coil transmits the position detection signal at a second phase obtained by inverting the first phase. Is divided into a third area that can be transmitted,
The signal transmitting means transmits the position detection signal at the first phase from the first transmission coil when the position indicator is located in the first area, and the position indicator is When the position indicator is located in the second region, the position detection signal is transmitted at the first phase from the second transmission coil, and when the position indicator is located in the third region, the first position detection signal is transmitted. 19. The position detecting device according to claim 18, wherein the position detecting signal is transmitted at a second phase from a transmitting coil. When the position indicator is located in the first area, the receiving means sequentially selects a plurality of predetermined sensor coils disposed in the first area and the periphery thereof and outputs a signal from the position indicator. Receiving, when the position indicator is located in the second area, sequentially receiving a signal from the position indicator by sequentially selecting a plurality of predetermined sensor coils disposed in the second area and the periphery thereof; When the position indicator is located in the third area, sequentially selecting a plurality of predetermined sensor coils disposed in the third area and the periphery thereof and receiving a signal from the position indicator. 20. The position detecting device according to claim 19, wherein:

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