JP3239195B2 - Position detecting device and position detecting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device and a position detecting method, and more particularly to an improvement of a position detecting device and a position detecting method of an electromagnetic induction type or an electrostatic induction type.

[0002]

2. Description of the Related Art In general, a conventional position detecting device is provided with a plurality of electrically equivalent position detecting members (antennas) capable of detecting an electric field or a magnetic field in either an electromagnetic induction system or an electrostatic induction system. A member having an action) disposed at predetermined intervals in the position detection direction, a position indicator incorporating a radiation unit for radiating an electric field or a magnetic field and movable on the tablet, and the plurality of position detections A processing device that performs position calculation (coordinate calculation) based on a signal (position signal) output by the member. The processing device obtains signals generated at each of the plurality of position detecting members by the action of electrostatic coupling or electromagnetic coupling caused by an electric field or magnetic field radiated from the radiation unit in the position indicator, and based on these signals, And has a function of calculating the coordinates of the position indicated by the position indicator on the tablet in the position detection direction, and the processing device is constituted by a signal processing circuit for taking in signals and processing means (including a CPU or the like). ).

In the above-described conventional position detecting device, a multiplexer is provided for a plurality of position detecting members, and a signal received by each of the plurality of position detecting members is sequentially acquired based on a switching operation of the multiplexer. Is performed to obtain position signals necessary for position calculation from a plurality of position detection members. The signal obtained by the multiplexer is transferred to a processing means through a signal processing circuit, where a coordinate calculation for obtaining a designated position is performed. In this configuration, a single signal processing circuit is provided for a plurality of position detection members. For example, an electromagnetic induction type position detecting device previously proposed by the present applicant (Japanese Utility Model Application Laid-Open No. 63-80635).
Is configured based on the above-described concept.

Referring to FIG. 6, a conventional state in which sequential scanning over time is performed will be described. In FIG.
FIG. 6A shows a scan state where the horizontal axis is the time axis and the vertical axis is the signal intensity. When the arrangement state of the position detecting members is schematically described, a large number of position detecting members are arranged at predetermined intervals for each of the X axis and the Y axis of the tablet,
A position indicator incorporating means for radiating an electric field or a magnetic field is movably arranged on the tablet. The position indicator strongly detects the signal of the position detection member closest to the indicated position in each of the X and Y directions. A selective connection means, usually a multiplexer, is provided between the plurality of position detection members and the signal processing circuit. In the case of the present embodiment, as shown in FIG.
It is assumed that five position detecting members are arranged in each of the axis directions of Y and Y, and the multiplexer sequentially selects the five position detecting members in the X-axis direction and sends their signals to a signal processing circuit. , And sequentially selects five position detection members in the Y-axis direction and sends the signals to a signal processing circuit. This is repeated as one cycle (time T as shown in FIG. 6B) at a speed that is practically acceptable, for example, about 200 times per second, and signal detection and position calculation for position calculation are performed. . As a specific example of the position calculation, for example, a method of converting the obtained signal into a digital value, selecting three from the largest, treating the signal as a quadratic function, and calculating the vertex thereof is adopted.

FIG. 6B shows the transmission power required when the position indicator emits an electric or magnetic field, wherein the horizontal axis represents time and the vertical axis represents power. Assuming that the scan time required for one position calculation is T described above, a constant transmission power is required during the time T.

FIG. 6C shows a case where scanning is performed in a state where no external noise is mixed. Since the position detection members arranged in parallel in the X-axis direction and the Y-axis direction are coils in the case of the electromagnetic induction method, they are described as X coils or Y coils in the drawing. In the signal shown in FIG. 6C, the X coordinate is calculated based on three signals obtained from the second, third, and fourth X coils. On the other hand, the Y coordinate is calculated based on three signals obtained from the second, third, and fourth Y coils.

[0007] FIG. 6 (d) shows a case where the external noise 61 is mixed at the time of scanning the second X coil.
In this case, the external noise 61 is the signal 62 obtained at that time.
, Which affects the calculation of the X coordinate. Here, the “external noise” is a concept including not only noise from outside the position detecting device but also noise generated from an electronic circuit provided in the position detecting device. Generally, a coordinate detector has a phenomenon called jitter, that is, a phenomenon in which the coordinates slightly fluctuate despite the fact that the position indicator is not moved. This phenomenon is caused by noise generated from an electronic circuit.

[0008]

In recent years, more and more portable computers have the above-described position detecting device incorporated therein. In portable computers, because there is a limit to the capacity of a battery to be mounted, reduction in power consumption is a challenge in order to extend the available time. The portion that consumes the most power in this type of position detecting device is a portion for generating an electric field or a magnetic field. Therefore, it is required to reduce the radiated power. However, if this requirement is satisfied, the S / N ratio of the received signal will be deteriorated. As a result, the performance as a result is reduced.

Further, in the above-described conventional example, since the scanning is sequentially performed with the lapse of time, a noise signal randomly input from the outside affects only the signal selected at the time of the noise generation. Generally, as described above, the position calculation is performed based on a plurality of signals, and therefore, only a part of the plurality of signals used for the position calculation includes noise, and as a result, the coordinates can be accurately calculated. There is a problem that the calculation cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a position detecting device and a position detecting method which can reduce the power consumption, eliminate the influence of external noise even if it is mixed, and improve the S / N ratio. is there.

[0011]

A position detecting device according to the present invention comprises a tablet and a position indicator, is arranged in a position detecting direction on the tablet, and receives an electric field or an electric field arriving from the position indicator side. A plurality of position detecting members for detecting a magnetic field and outputting position signals used for calculating a position indicated by the position indicator, and incorporating position signals output from each of the plurality of position detecting members. A position detecting device including a processing unit for calculating a position , wherein a plurality of position detecting units are provided.
Around the coordinate detection surface of the tablet
Provide a transmitting antenna to surround and transmit to the tablet side
Oscillation circuit, and the position indicator has a resonance circuit,
High-frequency power supplied from the transmission oscillation circuit is switched between transmission and reception
Supply to the position indicator via the road and via the transmission antenna
The resonance circuit of the position indicator resonates with the high-frequency power and
An electric field or a magnetic field is applied to the detection member, a plurality of signal processing circuits corresponding to each of the plurality of position detection members or a group of the plurality of position detection members, and a plurality of one or some of the plurality of position detection members. And a connection unit connected to any one of the corresponding signal processing circuits,
Position signals output from a plurality of position detection members are simultaneously received via a plurality of signal processing circuits, and are transferred to a processing unit.

In the above configuration, preferably, the position finger
For transmission necessary to generate an electric or magnetic field with the indicator
The high frequency power from the oscillation circuit is intermittently supplied in correspondence with the simultaneous intake.

In the above-mentioned configuration, preferably, a reference signal generating means for outputting a reference signal is provided, and the connection unit connects each input terminal of the plurality of signal processing circuits to an output terminal of the corresponding position detecting member. A connection selection circuit selectively connected to one of the output terminals of the reference signal generation means, and the processing means outputs an output value based on the position signal of each signal processing circuit based on the reference signal of the same signal processing circuit. Calibration means for calibrating with the output value is included.

In the above-mentioned configuration, preferably, a standard processing circuit is provided in parallel with the plurality of signal processing circuits, and the connection section connects each output terminal of the plurality of position detection members to the corresponding signal processing circuit. And a connection selecting circuit selectively connected to both the input terminal of the standard processing circuit and the input terminal of the standard processing circuit, and the processing means includes a calibration means for calibrating an output value of each signal processing circuit with an output value of the standard processing circuit. Including.

A position detecting method according to the present invention is a tablet
In to generate a position signal by detecting an electric field or a magnetic field coming from the side of the position indicator at a plurality of position detecting member arranged in the position detection direction is indicated by the position indicator by using a plurality of position signals This is a position detection method that calculates the position by using the transmission oscillation circuit provided on the tablet side.
High-frequency power supplied from road is detected by tablet coordinates
A transmitting antenna provided around the surface to surround it
Supplied to the position indicator via the
The resonance circuit resonates with the high-frequency power and
Apply an electric or magnetic field, multiple based on the electric or magnetic field
A plurality of position signals generated by the position detection member are simultaneously taken in, and the position is calculated using these position signals.

In the above method, preferably, high-frequency power supplied from a transmission oscillation circuit for generating an electric field or a magnetic field detected by a plurality of position detecting members is intermittently supplied in correspondence with the simultaneous intake. And, it is characterized in that a plurality of position signals are simultaneously taken in accordance with the time when power is supplied.

In the above method, preferably, a plurality of simultaneously acquired position signals are respectively introduced through a unique signal processing route, and for each position signal, a variation caused by a characteristic of each signal processing route is calibrated. For performing a signal calibration process.

[0018]

In the position detecting device according to the present invention, for each one or a plurality of grouped position detecting members arranged in the position detecting direction on the tablet,
A configuration in which a signal processing circuit for taking in an output signal is provided, and a plurality of position signals required for position calculation output from a plurality of position detection members are simultaneously taken in and processed by a configuration using the plurality of signal processing circuits. Becomes possible. This makes it possible to shorten the time for generating an electric field or the like for obtaining a plurality of position signals required for one position calculation, thereby shortening the power supply time and reducing power consumption. Furthermore, in order to incorporate multiple position signals at almost the same time, even if external noise is mixed in at that time, it will be added on all position signals, so it will not affect position calculation and correct position Can be calculated. In addition, the position detection method includes a step of taking in a plurality of position signals output from the plurality of position detection members at substantially the same time. The same operational features described occur.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention. The components of the position detection device shown in FIG. 1 are roughly classified into a tablet 10, a position indicator 20, a processing device 30, a connection device 40, and a transmission oscillation circuit 50. Hereinafter, each component will be described separately.

The illustrated tablet 10 is provided with five position detecting members 11 to 15 for convenience of explanation. The tablet 10 has a function as a position (coordinate) detection device,
It has a position (coordinate) detection surface. The position is specified by the X coordinate value and the Y coordinate value on the position detection surface. Therefore, the position detection surface is a coordinate input surface for inputting two-dimensional coordinates. The position detecting members are arranged side by side at predetermined intervals in each of the orthogonal X and Y directions, but the position detecting members in the X direction are partially shown as an example to avoid complexity. When a predetermined number of position detection members are provided in each direction of XY, a signal for detecting XY is provided by providing a circuit for switching XY or providing a plurality of signal processing circuits for each of XY. Will be done.

In the embodiment shown in FIG. 1, the position detecting members 11 to 15 are loop type coils. However, coils of other shapes may be used. In the case of the electromagnetic induction method, the position detection member is a coil as described above,
In the case of the electrostatic induction method, a member capable of detecting an electric field or its change is used. In the following description, the features of the present invention will be described with respect to the electromagnetic induction method. The features of the present invention include processing a plurality of signals detected by a plurality of position detecting members by a signal processing circuit corresponding to each signal. Since the processing is performed in parallel by a plurality of signal processing circuits, the present invention can be applied to a position detection device of another system such as an electrostatic induction system.

The position indicator 20 can freely move on the position detecting surface of the tablet 10 by a moving operation by an operator, and can indicate a desired position. In the present embodiment, since the position indicator 20 adopts a structure that is cordless and does not incorporate a power battery, the tablet 1
A transmission antenna 16 is provided around the zero coordinate detection surface so as to surround it, and the transmission antenna 16 is connected to a transmission oscillation circuit 50 as power supply means. On the other hand, the position indicator 20 is provided with a resonance circuit (consisting of a coil 21 and a capacitor 22). Electromagnetic waves are transmitted and received between the transmission antenna 16 and the resonance circuit of the position indicator 20. It is also possible to provide a battery and an oscillation circuit inside the position indicator 20, and it is also possible to connect a cord to the position indicator 20 and supply power from the tablet 10 side.

Coil 21 provided in position indicator 20
And the capacitor 22 has a resonance frequency substantially the same as the frequency of an alternating magnetic field or a radio wave generated by the transmission oscillation circuit 50 and transmitted via the transmission antenna 16. The capacitor 23 includes a switch 24
Can be added to the resonance circuit by turning on, thereby changing the capacitance of the resonance circuit and slightly changing its resonance frequency. Position indicator 2
When the switch 24 of “0” is turned on, switch information relating to the operation is stored in the tablet 10 in the position detecting device.
It is transmitted to the main unit including the computer and the processing device 30. The transmission method will be described later. Although the number of switches 24 is one in the illustrated example, two or more switches 24 can be provided as necessary.

Next, a description will be given of a configuration and an operation for transmitting switch information relating to the operation when the switch 24 of the position indicator 20 is turned on to the main unit of the position detecting device. The high-frequency current output from the transmission oscillation circuit 50 reaches the position indicator 20 via the amplifier 51, the transmission / reception switching circuit 58, and the transmission antenna 16 as an alternating magnetic field or a radio wave. The resonance circuit including the coil 21 and the capacitor 22 provided in the position indicator 20 generates a resonance action on the alternating magnetic field or the radio wave, and returns the alternating magnetic field or the radio wave having substantially the same frequency to the tablet 10 side.
At this time, the transmission / reception switching circuit 58 is switched, and the transmission coil 16 receives the alternating magnetic field or the radio wave which is reflected and returned from the position indicator 20 side, and passes the received signal via the amplifier 52. The signal is sent to the phase comparator 53. The phase comparator 53 compares a signal from the amplifier 52 with a signal supplied from the transmission oscillation circuit 50 and outputs an output corresponding to the difference via a low-pass filter (LPF) 54 to a signal holding circuit (S / H). ) 55. Signal holding circuit 55
A / D converter (A / D)
After being converted into a digital value by 56, the processing device 30
It is sent to a central processing unit (CPU) 39 provided therein. The CPU 39 knows whether or not the switch has been turned on based on the value, and outputs the information as switch information to an external device such as a host computer.

Next, a configuration relating to a position (coordinate) detecting operation which is a feature of the present invention will be described. A feature of the present invention is that a plurality of signal processing circuits 31 to 35 are provided in parallel in the processing device 30 and the connection device 40 is connected to the position detecting member 11.
To 15 are connected to the signal processing circuits 31 to 35, respectively. Each signal processing circuit includes, for example, an amplifier, a band-pass filter (BPF), a detection circuit (DET), an integration circuit (low-pass filter: LPF), as shown in FIG.
The signal holding circuits (S / H) are arranged in series.

The connection device 40 includes connection circuits 41 to 4
6. Each of the connection circuits 41 to 46 connects each of the signal processing circuits 31 to 35 to the corresponding position detection member 11 to 15 or the ground. In the connection device 40, the connection circuits 41 to 45 are configured to operate at the same time, whereby the signals generated in each of the position detection members 11 to 15 (the position signals used for the position calculation) are simultaneously transmitted. The signal processing circuits 31 to 35 perform signal processing at the same time. Here, the “simultaneous” is simultaneous in the sense that when the external noise occurs, the external noise is mixed into all of the plurality of signals.

The alternating magnetic field or radio wave reflected and returned from the above-mentioned position indicator 20 is transmitted to the position detecting members 11 to 15.
Then, an electric signal (position signal) is generated based on the electromagnetic coupling action. The signal processing circuits 31 to 35 are connected to the connection device 4
The signals are respectively received via the signals 0 and processed in parallel, so that the five types of signals are finally held in the respective signal holding circuits. The signals held by the signal holding circuits of the signal processing circuits 31 to 35 are input to the input switching circuit 59 and the A / A
After being converted into a digital value through a D converter (A / D) 38, a central processing unit (CPU) 3
9 is transmitted. The central processing unit 39 controls the tablet 10 of the position indicator 20 based on the five types of position signals.
The XY coordinates of the above indicated position are calculated. As the calculation method, as described in the section of the prior art, a method of obtaining the vertices by approximation with, for example, a quadratic function is used.
The calculated XY coordinates are sent to an external device such as a host computer via an interface circuit (not shown) together with the operation information of the switch 24 described above.

With the configuration of the parallel processing described above, power consumption can be reduced and the S / N ratio can be improved. The reason why such an effect occurs will be described with reference to FIG.

FIG. 2A shows signal detection timings t1 and t1 in a three-dimensional space consisting of a time axis (t), an axis representing a coil type (coil No.), and an axis representing signal strength.
This shows t2. Areas 25 and 26 indicated by oblique lines
Shows the level state of the signal generated in each of the X and Y coils when the signal is detected. When FIG. 2A is compared with FIG. 6A, according to the configuration of FIG. 1, the detection of the signals related to the five X coils and the five Y coils is performed in a time that is reduced to about one tenth. Can be detected. That is, if the position indicator 20 emits an alternating magnetic field or a radio wave for 1/10 of the time T, the position detecting members 11 to 15 simultaneously detect this by electromagnetic coupling and generate an electric signal. .

FIG. 2B shows the generation time of the transmission power in the case of the present embodiment. Compared with FIG. 6 (b) in the conventional case, while the conventional transmission of the fixed transmission power is continuously performed for the time T for each set of XY coordinate detection, in the case of the present embodiment, Same power 1/10 of time T
Indicates that it is sufficient to send only

FIG. 2C shows a state of influence on the detection signal when external noise is generated at the time of signal detection. According to the configuration of the present embodiment, the generated external noise 27 is generated by simultaneously outputting the signals output from the signal detection members of the XY coils by the corresponding signal processing circuits. They will be superimposed on each other.

From the above, it is possible to reduce the power consumption by reducing the transmission power. Generally, by setting the number of signal processing circuits that perform parallel processing to N,
The power consumption related to the transmission power can be reduced to 1 / N. The improvement of the S / N ratio is achieved based on the following reason with reference to the noise mixing characteristics shown in FIG.

First, as shown in FIG. 2C, when external noise is mixed in the detection signal,
Since the acquisition timings of the detection signals are substantially the same, external noise is equally mixed in all the signals, in other words, the external noise has the same effect, and as a result,
In the calculation of the coordinates, the external noise is canceled, the influence of the external noise is removed, and the S / N ratio is improved.

Second, considering the source of noise, a digital signal is more likely to cause noise than an analog signal. In the circuit shown in FIG. 1, a digital signal is generated by an A / D converter or a CP.
It is a peripheral location where U is provided. As described above, by making the transmission power generation timing 1/10 as compared with the conventional case, it becomes easy to shift the period for performing signal processing in the digital circuit and the period for generating transmission power. FIG.
In the conventional configuration shown in (1), the transmission power generation period and the digital signal processing period overlap, whereas in the configuration of the present embodiment, the digital signal is prevented from being superimposed on the signal detected by the position detecting member. By shifting the transmission power generation period and the digital signal processing period, the S / N ratio can be improved.

In the position detecting device shown in FIG. 1, two configurations for reducing power consumption are added in addition to the configuration of the parallel processing related to the signal processing circuit.

The first configuration is to transmit the signal obtained by the signal holding circuit 55 to the transmission oscillation circuit 50. With this configuration, the frequency of the transmission oscillation circuit can be made to match the frequency of the received signal. Since the energy loss is reduced when the frequencies of the transmission signal and the reception signal are as close as possible, the power consumption can be reduced.

The second configuration is that a power controller 57 is provided. The power controller 57 has a function of controlling the intensity of a signal output from the transmission oscillation circuit 50. The intensity of the signal detected by the position detection members 11 to 15 depends on the intensity of the signal generated by the transmission oscillation circuit 50. Therefore, when the detected signal strength is sufficiently high, the power supply level supplied to the transmission oscillation circuit 50 is reduced, and when the detected signal strength is low, the power supply level is increased, thereby eliminating waste of power. Thus, power consumption can be reduced.

FIG. 1 shows a configuration in which the transmission coil 16 also serves as the reception coil by the switching operation of the transmission / reception switching circuit 58, but the reception coil may be provided separately from the transmission coil 16. Further, each of the position detection members 11 to 15 may be configured to use either or both of the transmission antenna and the reception antenna.

FIG. 3 shows another embodiment of the structure of the connection device 40 when there are 15 position detecting members and only 5 signal processing circuits are provided. The fifteen position detecting members are denoted by reference numerals A to O, respectively. The signal processing circuits 31 to 35 shown in FIG. 1 are assumed, and connection circuits 41 to 45 are provided corresponding to these signal processing circuits 31 to 35, respectively. The connection circuit 41 is connected to any of the position detection members A, F, and K,
The connection circuit 42 is connected to one of the position detection members B, G, and L, the connection circuit 43 is connected to one of the position detection members C, H, and M, and the connection circuit 44 is connected to the position detection members D, I, and
M, and the connection circuit 45 is connected to any of the position detecting members E, J, and O. In each connection circuit, preferably, a connectable ground terminal is provided as shown in FIG. In FIG. 3, it is omitted for simplicity of illustration.

Next, a procedure in which signals output from the position detecting members A to O are selected and taken in by the connecting device 40 having the configuration shown in FIG. 3 will be described. This procedure is stored in a memory such as a ROM (not shown) in advance, and the CPU 39 executes the connection circuit 4 according to the procedure.
The switching operation of 1 to 45 is performed, and X is determined based on the obtained signal.
Calculate the Y coordinate.

For convenience of description, the unit period in which the switching operation of the connection device 40 or the transmission / reception switching circuit 58 is performed is defined as a period 0,
Period 1, Period 2, etc. In addition, in the adjacent period, a period serving as a gap is provided as needed, but in order to avoid complexity, the description will be made assuming that each period is continuous.

First, in period 0, the transmission / reception switching circuit 58 in FIG. 1 is on the transmission side, and the connection circuits 41 to 45 are connected to ground terminals. This is to eliminate a signal generated in the position detecting member due to an electrical coupling action based on an alternating magnetic field or a radio wave emitted from the transmission circuit 16. In the period 1, the transmission / reception switching circuit 58 is switched to the reception side. The connection circuit 41 is connected to the position detection member A, the connection circuit 42 is connected to the position detection member B, the connection circuit 43 is connected to the position detection member C,
The connection circuit 44 is connected to the position detection member D, and the connection circuit 45 is connected to the position detection member E. Hereinafter, such a connection state in the connection device 40 is expressed as “the connection device 40 is (A, B, C, D, E)”.

The transmission / reception switching circuit 58 is connected to the transmission side during the even periods of the periods 0, 2, 4,... And to the reception side during the odd periods of the periods 1, 3, 5,. Correspondingly, each connection circuit of the connection device 40 is connected to the ground terminal side in an even period and connected to the position detection member in an odd period. Scanning for position calculation is performed by dividing into a whole scan and a partial scan. Next, a scanning procedure considered to be most effective in the configuration shown in FIG. 3 will be described.

In the whole scan, the connection devices 40 are (A, B, C, D, E) in periods 1, 3, and 5, respectively.
(F, G, H, I, J) and (K, L, M, N, O). The CPU 39 fetches the signals into a storage device (not shown) such as a buffer memory as signals of the position detecting members A to E in period 2, fetches the signals as signals of the position detecting members F to J in period 4, It is taken in as signals of the detection members K to O. Further, in period 6, which of the 15 signals taken in has the maximum value by comparison, a set corresponding to this maximum value is determined according to a correspondence table prepared in advance. More specifically, for example, when the maximum value is “J”, the set to be obtained is (F, G, H,
I, J). This set is for selecting five position detection members centering on "J". The above is the overall scanning procedure.

The partial scan is performed in period 7 by the connecting device 40 performing the connecting operation in accordance with the set obtained by the whole scan. In a period 8, coordinates are calculated based on five signals obtained by the partial scan.

The above scanning method is merely an example,
Various other scanning methods can be performed. In the above description, it is described that the transmission power is in the ON state over the entire even period. However, the supply time of the transmission power is sufficient for the minimum time necessary to excite the position indicator 20. . As a result, power consumption can be reduced.

FIG. 4 shows an embodiment in which a reference signal generating circuit 36 and an input connection selecting circuit 46 are provided to calibrate a detection signal. The reference signal generation circuit 36 is a circuit that stably generates the same reference signal. The input connection selection circuit 46 is a connection circuit that selects whether a signal to be input to the signal processing circuits 31 to 36 is a signal from the position detection members 11 to 15 or a signal from the reference signal generation circuit 36. It is.

In general, it is desirable that all of the signal processing circuits 31 to 35 have the same operating characteristics, but they may vary in some cases. Therefore, the input connection device selection circuit 4
It is configured to set a period for periodic calibration based on the selecting operation of No. 6. The reference signal from the reference signal generation circuit 36 is sequentially sent to the signal processing circuits 31 to 35 by the selection operation of the input connection selection circuit 46. If the operating characteristics of each signal processing circuit vary, the outputs P and P are output to the signal processing circuits 31 to 35 based on the reference signal.
Q, R, S, and T occur. In this case, after this calibration operation, between the next calibration operations, for example, the position detecting member 1
The output of the signal processing results from 1 to 15 is a value obtained by multiplying the output value of the signal processing circuit 31 by the value of P / Q as it is for the output value of the signal processing circuit 31 and the output value of the signal processing circuit 33. The value is a value multiplied by the value of P / R, the output value of the signal processing circuit 34 is a value multiplied by the value of P / S, and the output value of the signal processing circuit 35 is a value multiplied by P / T. Is used to calculate the position.

The above-mentioned "calibration" will be referred to as "reference signal calibration" in this embodiment. The means for performing the reference signal calibration is included in the functional means of the CPU 39,
Performs a calibration process according to a procedure stored in a ROM or the like (not shown). The CPU 39 also controls the switching operation of the input connection selection circuit 46.

The above-described reference signal calibration is generally performed periodically at a fixed period, and is preferably performed every time the XY coordinates are calculated several times. Also, instead of performing the measurement periodically, it is also possible to provide a means for detecting the occurrence of any abnormality, so that the calibration is performed when the abnormality is detected.

FIG. 5 shows another embodiment. In this embodiment, a standard processing circuit 37 and an output selection connection circuit 47 are added to the configuration shown in FIG. 1, and calibration is performed by these circuits. ing. Other configurations are the same as those shown in FIG. 1, and the same elements are denoted by the same reference numerals. The calibration of this embodiment is referred to as “standard processing calibration” to distinguish it from the calibration of the previous embodiment. The means for performing the standard processing calibration is included in the functional means of the CPU 39,
Performs the calibration process according to the procedure stored in the ROM or the like. The standard processing circuit 37 is a circuit provided in parallel with the signal processing circuits 31 to 35 and separately provided as a similar signal processing circuit.

The output selection connection circuit 47 includes the position detection member 1
This is a connection circuit for selecting whether to output signals from 1 to 15 to the signal processing circuits 31 to 35 or to the standard processing circuit 37, and the selection operation is performed under the control of the CPU 39. The connection operation for outputting to the standard processing circuit 37 is performed periodically, and the cycle is usually set longer than the cycle set for calculating the coordinates.

An example of the standard processing calibration will now be described. Immediately after a signal from the position detecting member 11 is sent to the signal processing circuit 31, based on the connection operation of the output connection selecting circuit 47, the signal is processed by the standard processing circuit. Suppose that it was also sent to 37. Assuming that the output values at this time are U and V, respectively, during the period from this calibration to the next calibration, the output value of the signal processing circuit 31 is defined as a value obtained by multiplying the actually output value by V / U. Replace it for use in position calculation. Other signal processing circuit 3
The same applies to the output values 2 to 35. However, if this calibration is performed frequently, the advantage of the configuration of the parallel processing is impaired. Therefore, it is desirable to perform the standard processing calibration with the period required for performing the position calculation several times or several tens of times as a cycle.

[0055]

As is apparent from the above description, according to the present invention, a configuration is adopted in which a plurality of position signals used for position calculation are simultaneously taken into the processing device, and the plurality of position signals are generated. Power to generate an alternating magnetic field, etc., to reduce the power consumption and to specify the correct position without affecting the position calculation even if external noise is mixed. Can be obtained, and the S / N ratio can be improved. Further, by adding the calibration processing, it is possible to adjust the variation in the operating characteristics between the plurality of signal processing circuits.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment according to the present invention.

FIG. 2 is a diagram for explaining reduction of power consumption and improvement of an S / N ratio.

FIG. 3 is a diagram illustrating a configuration of a connection device when there are 15 position detection members and 5 signal processing circuits.

FIG. 4 is a configuration diagram illustrating an embodiment in which calibration is performed using a reference signal.

FIG. 5 is a configuration diagram showing an embodiment in which calibration is performed using a standard processing circuit.

FIG. 6 is a diagram illustrating a state of sequential scanning over time in a conventional position detection device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 tablet 11 to 15 position detecting member 16 transmitting antenna 20 position indicator 30 processing device 31 to 35 signal processing circuit 36 reference signal generating circuit 37 standard processing circuit 40 connecting device 41 to 45 connecting circuit 46 input connection selecting circuit 47 output connection selecting Circuit 50 Transmission oscillation circuit

Claims (7)

(57) [Claims] 1. A tablet device comprising: a tablet; a position indicator;
Are arranged in the position detecting direction at Brett, by detecting the electric or magnetic field coming from the side of the position indicator, the position indicator calculated more for outputting a position signal used for position indicated by In a position detecting device, comprising: a position detecting member , and processing means for calculating the position by taking in the position signals output from each of the plurality of position detecting members, wherein the tablet on which the plurality of position detecting members are arranged of
A transmitting antenna is set around the coordinate detection surface so as to surround it.
A tablet oscillation circuit on the tablet side; and
The position indicator has a resonance circuit, and transmits and receives high-frequency power supplied from the transmission oscillation circuit.
The position via a switching circuit and via the transmitting antenna
Supply to the indicator, the resonance circuit of the position indicator is
Resonates with high-frequency power and applies the power to the position detecting
Applying a field or the magnetic field, a plurality of signal processing circuits respectively corresponding to each of the plurality of position detection members or a group of some, and one or some of the plurality of position detection members A connection unit connected to any one of the corresponding signal processing circuits, and simultaneously taking in the position signals output by the plurality of position detection members via the plurality of signal processing circuits; A position detecting device for transferring. 2. The position detecting device according to claim 1, wherein
The high-frequency power from the transmission oscillation circuit required to generate the electric field or the magnetic field with the position pointer
Is intermittently supplied in response to the simultaneous
Position detecting device, characterized in that that. 3. The position detecting device according to claim 1, wherein
Reference signal generating means for outputting a reference signal is provided, and the connection section connects each input terminal of the plurality of signal processing circuits to a corresponding output terminal of the position detection member and an output terminal of the reference signal generating means. And a processing unit for calibrating an output value based on the position signal of each signal processing circuit with an output value based on the reference signal of the same signal processing circuit. A position detecting device comprising: 4. The position detecting device according to claim 1, wherein
A standard processing circuit is provided in parallel with the plurality of signal processing circuits, and the connection unit connects each output terminal of the plurality of position detection members with an input terminal of the corresponding signal processing circuit and the standard processing circuit. A connection selection circuit selectively connected to both input terminals of the circuit; and the processing means includes a calibration means for calibrating an output value of each of the signal processing circuits with an output value of the standard processing circuit. Position detecting device. 5. A plurality of position detecting members arranged in a position detecting direction on a tablet detect an electric field or a magnetic field arriving from a position indicator side to generate a position signal, and utilize the plurality of position signals. In a position detection method for calculating a position indicated by the position indicator by calculation, a signal is supplied from a transmission oscillation circuit provided on the tablet side.
High-frequency power supplied to the coordinate detection surface of the tablet.
The transmitting antenna provided so as to surround it around
Supply to the position indicator via the
The resonant circuit is resonated with the high frequency power and the position
Applying the electric field or the magnetic field to a detection member, and detecting the plurality of positions based on the electric field or the magnetic field;
Simultaneously taking in the plurality of position signals generated by the member ,
A position detecting method, wherein the position is calculated using these position signals. 6. The position detecting method according to claim 5, wherein
Before being supplied from the transmission oscillation circuit for generating an electric field or a magnetic field detected by the plurality of position detection members
A position detecting method, wherein the high-frequency power is intermittently supplied in correspondence with the simultaneous taking-in, and the plurality of position signals are taken-in simultaneously in accordance with a timing at which the power is supplied. 7. The position detecting method according to claim 5, wherein
The plurality of position signals which are taken in at the same time are taken through respective signal processing routes, and each position signal is subjected to a signal calibration process for calibrating a variation caused by a characteristic of each signal processing route. A position detecting method characterized by the above-mentioned.