JPH0384613A - Input device - Google Patents

Abstract

PURPOSE:To attain the input of the coordinate data with use of plural wireless movable matters based on the coil output signal by setting a pair of coils which are separate from each other by a prescribed distance and energized with switch of the frequency. CONSTITUTION:The detection coils 26C - 29C containing a pair of coils con nected in an 8-shape respectively for mutual elimination of the induced voltage are set at the prescribed positions. These coils are energized by an energizing coil 24 with switch of the frequency. Therefore the position information on the resonance coils provided to the movable matters 35A and 35B are detected as the amplitude information on the output signals VX1, VX2, VY1 and VY2 with resonance frequency of the resonance coils and based on the center axis O of each detection coil. Thus it is possible to identify the matters 35A and 35B and to input the coordinate data with input of the phase comparison result obtained to the drive signal of the coil 24 carried out on the basis of the drive frequency of the coil 24.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Industrial field of application B. Overview of the invention C. Conventional technology D. Problems to be solved by the invention E. Means for solving the problems (Figs. 1, 5 to 7)
Figure) 1 Effect (Figures 1, 5 to 7) G Example (G1) Position detection principle (Figures 1 to 3) (G2) Principle of identifying objects that disturb the magnetic field (Figures 4 and 7) (Fig. 5) (G3) First embodiment (Figs. 6 and 7) (G4) Other embodiments (Figs. 8 and 9) H Effects of the invention A Industrial application field The present invention is Regarding input devices, the present invention is suitable for application to, for example, input devices for handwritten documents.

B. Summary of the Invention The present invention provides an input device in which a set of coils, which are arranged at a predetermined distance and are excited by switching the frequency, are arranged at a predetermined interval apart. Based on the output signal of the coil, coordinate data can be input using a plurality of wireless movable bodies.

Furthermore, according to the second invention, coordinate data can be input by using a plurality of movable bodies simultaneously by using a movable body having a resonant circuit.

C. PRIOR TECHNOLOGY Conventionally, when handwritten characters are input into a computer or the like, two-dimensional coordinate data input means such as a digitizer or a mouse are used.

In this type of two-dimensional coordinate data input means, a movable body equipped with an excitation coil is moved over a tablet in which a predetermined detection coil is embedded, and an induced electromotive force excited in the detection coil at this time is detected. , the two-dimensional coordinate data of the movable body is detected.

Therefore, by continuously detecting coordinate data while moving the movable body, it is possible to manually write handwritten characters.

Further, by switching a switch provided on the movable body, the processing mode of coordinate data can be changed, and thereby the display of manually generated characters can be changed.

Problems to be Solved by the Invention In this type of two-dimensional coordinate data input means, it is necessary to supply an excitation current to the movable body in order to drive the excitation coil.

Furthermore, in a movable body equipped with a switch, it is necessary to transmit the switching of the switch to the computer.

Therefore, in conventional two-dimensional coordinate data input means,
There is a problem in that the wire extends from the movable body, and coordinate data must be input while dragging the wire.

That is, when inputting handwritten characters or the like while dragging a wire, not only does it become inconvenient to use, but also failures such as wire breakage are inevitable.

The present invention has been made in consideration of the above points, and aims to propose an input device that can manually input coordinate data using a wireless movable body.

E Means for Solving the Problem In order to solve this problem, in the present invention, an excitation coil 24 that generates a predetermined excitation magnetic field Φ, and an excitation coil 24 that is arranged at a predetermined distance apart and are excited by the excitation coil 24 are provided. First and second coils 26CL and 26 that generate induced voltage
CR, and first and second coils 2 separated by a predetermined distance.
6CL and 26CR are arranged in the arrangement direction
The third and fourth coils 27CL and 27CR are arranged such that their arrangement positions are shifted by a predetermined interval L/2 with respect to the arrangement positions of the coils 26CL and 26CR, and a drive signal that outputs a drive signal SD to the excitation coil 24. Creation circuit 15
．． 17.19.21.22 and the frequency f of the drive signal SD
.
Based on the differential voltage Xt between the induced voltages of L and 27CR, the first and second coils 26CL and 26CR and the third
The movable bodies 35A and 35B placed on the fourth coils 27CL and 2TCR are detected, and the movable bodies 35A and 35B are identified based on the frequencies f, , f2 of the drive signal SD.

Furthermore, in the second invention, the movable bodies 35A, 35B connect the capacitors C1, C2 and the coils L1, L2 excited by the exciting magnetic field Φ, and
A resonant circuit 9C19D that resonates at , , f is provided.

1 Effect In the first invention, the first to fourth coils 26CL to 27 which are excited by the excitation Kn-r coil 1 and generate an induced voltage.
The induced voltage in CR changes according to disturbances in the excitation magnetic field Φ.

Therefore, the first and second coils 26CL and 26CR arranged at a predetermined distance apart, and the third and fourth coils 2
In 7CL and 27CR, the balance of the induced voltage is lost depending on the positions of objects L1 and L2 that disturb the excitation magnetic field Φ, and the balance between the first and second coils 26CL and 26CR and the third coil
And based on the fourth coils 27CL and 27CR,
Position information of objects L1 and L2 that disturb the excitation magnetic field Φ can be detected as amplitude information.

Furthermore, if the frequency of the excitation magnetic field Φ is switched at this time, when an object that disturbs the excitation magnetic field Φ resonates with the frequency f, , f of the excitation magnetic field Φ, the position information of the object that disturbs the excitation magnetic field Φ can be changed to an amplitude It can be information, and coordinate data can be input.

Furthermore, the excitation [
It is possible to identify movable bodies 35A and 35B in which objects that disturb the magnetic field Φ are arranged.

Furthermore, in the second invention, if the movable bodies 35A and 35B are provided with a resonant circuit that resonates at the predetermined frequencies fire and rz of the drive signal SD, the coordinate data D can be inputted while distinguishing them from other movable bodies. be able to.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

(G1) Position detection principle As shown in FIG. Two coils 4 and 5 are placed in Φ.

The coils 4 and 5 have rectangular openings with the same area, and are arranged so that the opening surfaces thereof are parallel to the opening surface of the excitation coil 1.

Further, the coils 4 and 5 are arranged at a predetermined distance apart so that one side overlaps and forms a figure 8 shape.

As a result, in the coils 4 and 5, as long as the excitation magnetic field Φ is not disturbed, the magnetic flux interlinking with the excitation magnetic field Φ is held equal, and the excitation coil 1 is excited to generate an equal induced voltage. ing.

Furthermore, the coils 4 and 5 are connected so that one side of each other overlaps with each other, so that the induced voltages of the coils 4 and 5 are canceled out by each other.

Therefore, one side of the four coils is connected to the amplifier circuit 7 and the output voltage is ■. As long as the excitation magnetic field Φ is not disturbed, a balanced induced voltage can be obtained, and the output voltage ■. can be maintained at O level.

On the other hand, if, for example, a metal piece or the like is placed in the excitation magnetic field Φ to disturb the excitation magnetic field Φ, the induced voltage in each of the coils 4 and 5 will change accordingly, and the output voltage will correspond to the change. can be obtained.

At this time, as shown in FIG. 2, an axially symmetrical disk-shaped metal piece 8 is placed on one side where the coils 4 and 5 overlap (hereinafter, the axis on this one side will be referred to as the central axis O). For example, by generating an eddy current in the metal piece 8, the excitation magnetic field Φ is disturbed with the center axis O as the axis of symmetry.

In this case, in the coils 4 and 5, the induced voltage changes in a balanced state, and even though the excitation magnetic field Φ is disturbed, the output voltage is ■. is held at O level.

On the other hand, if the metal piece 8 is shifted from the central axis O, the excitation M1 magnetic field Φ will be generated on the coil 4 side and the coil 5 side accordingly.
exhibits different disturbances.

Therefore, in this case, the balance of the induced voltages in the coils 4 and 5 is disrupted, and the amplitude of the output large voltage V0 changes from the 0 level accordingly.

Therefore, as shown in FIG. 3, if the distance from the central axis O to the metal piece 8 is T in the direction in which the coils 4 and 5 are continuous, the output voltage is . (FIG. 3(A)) can be approximately expressed by the following formula (1).

Here, L is the length of one side of coil 4.5 in the direction of distance T, sinωt is the drive signal of exciting coil 1, and KI
A represents a proportionality constant.

In this way, the coils 4 and 5 are arranged at a predetermined distance apart in the excitation magnetic field Φ and connected so that the induced voltages cancel each other out, so that the coil 4 is The balance of the induced voltage of 5 and 5 is lost, and the output voltage becomes ■. A shift in the balance of this induced voltage can be detected through this, and thereby position information T of the metal piece 8 that disturbs the excitation magnetic field Φ can be detected as amplitude information.

Therefore, by using an object, such as a metal piece 8, as a movable body that disturbs the balance of the coils 4 and 5, coordinate data can be input wirelessly.

Incidentally, if the coils 4 and 5 that generate the induced voltage so as to cancel each other out are formed in a figure-eight shape, the coils 4 and 5 having the same shape can be created with high precision, and the output voltage v0 can be When outputting via the lead wire, the influence of the excitation magnetic field Φ can be effectively avoided and the output can be easily performed, thus allowing position information to be input with high precision.

(G2) Principle for identifying objects that disturb the excitation magnetic field By the way, if coordinate data can be input using a plurality of movable bodies that are coordinate data input means, the usability of the input device can be improved.

That is, if coordinate data can be input using a plurality of movable objects at the same time, for example, a plurality of people can input handwritten characters at the same time.

Furthermore, if it is possible to manually use a plurality of movable bodies alternately and switch the processing mode of input coordinate data depending on the movable body, for example, the display mode of handwritten characters can be switched.

For this purpose, it is necessary to identify the movable body and input coordinate data.

In this case, as shown in FIG. Place it in

In this way, the coil L1 is excited by the excitation magnetic field Φ, an induced voltage is generated, and a current flows through the coil L1 via the resistor R1.

Therefore, it can be seen that the excitation magnetic field Φ is disturbed by the current flowing through the coil L1, and the coil L1 terminated with the resistor R1 can be used as an object that disturbs the excitation magnetic field Φ.

Therefore, if the coil L1 terminated with the resistor R1 is used instead of the metal piece 8, then (1) for the coil L1 can be obtained.
The relationship of the formula can be obtained, and the position information T of the coil L1 is the output voltage ■. can be detected as amplitude information.

Furthermore, at this time, if the resistance value of the resistor R1 is made small, a large current flows through the coil L1, so that a large value can be obtained as the proportionality constant KIA in equation (1).

Therefore, coil L1 terminated with resistor R1 and resistor R2
When the coil L2 terminated at It turns out that it can be identified.

That is, since the proportionality constant KIA changes according to the degree of coupling between the coil 4.5 and the exciting coil 1, which changes according to the object existing in the excitation magnetic field Φ, by detecting ^ in the proportionality constant, By detecting the degree of coupling, it is possible to identify objects present in the excitation magnetic field Φ.

Therefore, for example, based on the identification results of coils L1 and L2,
The usability of the input device can be improved by switching the display of coordinate data input with handwritten characters.

On the other hand, as shown in FIG. 5, a coil Ll (hereinafter referred to as a resonant coil) coupled to the excitation magnetic field Φ, a resistor R1, and a capacitor CI are connected in series and placed in the excitation magnetic field Φ instead of the metal piece 8. do.

In this case, resonant coil L1, resistor R1 and capacitor C
Since a series resonant circuit 9C is formed by I, when the excitation coil 1 is driven at the resonant frequency f determined by the following formula (2),
The largest current flows through the resonant coil Ll.

Furthermore, at this time, if the resistance value of the resistor R3 is selected to be a small value and the sharpness Q of the series resonant circuit is increased, the largest current can be passed through the resonant coil L1 at the resonant frequency f, whereas the frequency of the drive signal When the current flowing through the resonant coil L1 is displaced from the resonant frequency f, the current flowing through the resonant coil L1 can be maintained at almost zero.

Therefore, resonant coil L2, capacitor C2 and resistor R2
The resonant circuit 9C and the resonant circuit 9D with different resonant frequencies are connected to 1
JIFli.
On the other hand, if the excitation coil l is driven at the resonant frequency of the resonant circuit 9D, the relationship of equation (1) can be obtained only for the resonant coil L2 of the resonant circuit 9D.
1) It is possible to obtain the relationship of Eq.

As a result, when inputting coordinate data, the resonant coils L1 and L2, which are configured to form a resonant circuit, are excited by the excitation magnetic field Φ
It can be seen that the position information can be input as amplitude information by using the object as a disturbing object.

Furthermore, it can be seen that even when resonant coils L1 and L2 with different resonance frequencies are placed in an excitation magnetic field Φ at the same time, by sequentially switching the frequency of the excitation magnetic field Φ, it is possible to identify objects that disturb the excitation magnetic field Φ based on the resonance frequency. .

On the other hand, if the resonant frequencies of the series resonant circuits 9C and 9D are selected to be the same frequency, and the resistors R1 and R2 are selected to have different resistance values, the coupling of the excitation coil 1 can be improved as described above for the parallel circuits 9A and 9B. The proportionality constant KIA changes depending on the degree.

Therefore, it can be seen that when the resonant coils L1 and L2 are selected to have the same resonant frequency, the resonant coils can be identified by alternately arranging them in the excitation magnetization Φ and detecting the degree of coupling.

(G3) First Embodiment (G3-1) Configuration of Embodiment In this embodiment, coordinate data is input simultaneously using a plurality of movable bodies based on this principle.

That is, in FIG. 6, 10 indicates a two-dimensional coordinate data input device as a whole, and a control circuit 1 having an arithmetic processing circuit configuration.
A clock signal SCK of a predetermined frequency is generated in accordance with a control signal Sc outputted from 1.

That is, the clock signal generation circuit 12 is a PLL (pha
se 1ocked 1oop) consists of an oscillation circuit,
By switching the frequency division ratio according to the control signal Sc,
A clock signal 5CII whose clock frequency is switched at predetermined intervals is used, and the two-dimensional coordinate data input device 10 operates based on the clock signal SCK.

On the other hand, the address counter circuit 15 sequentially and cyclically counts the clock signal S0 to create address data DADD for the one-drive only memory circuit (ROM) 17.

The read-only memory circuit 17 is configured to store one cycle of waveform data DWAV of a sine wave signal, and stores the waveform data I)w based on address data DADD.
Avt is sequentially and cyclically output.

On the other hand, the analog-to-digital conversion circuit 19 converts the waveform data D. After converting AVE into an analog signal, it is applied to the exciting coil 24 at a predetermined signal level via the amplifier circuit 21 and the signal level correction circuit 22.

Thus, in the excitation coil 24, the clock signal S0
The sine wave drive signal S is driven by a sine wave signal with a frequency determined by f2, and the clock frequency is switched at predetermined intervals, so that the frequency is switched at f2.

It is designed to be driven by.

As shown in FIG.
and is housed within a plastic cover 32, constituting a tablet 34 as a whole.

In other words, the printed circuit boards 26, 27, 28 and 29 are connected with wiring patterns formed on both sides through through holes so that the figure-8-shaped detection coils 26C, 127C, 128C and 29C described above with reference to FIG. 1 are formed. is being done.

Here, the detection coil 26C includes coils 26CL and 26C.
Detection coils 27C128C129C are connected to coils 27CL and 27CR, coils 28CL and 28C, respectively, while R is connected so as to cancel out the induced voltage.
R, coils 29CL and 29CR are connected so as to cancel out the induced voltages.

Thus detection coils 26C127C128C and 29C
, the excitation coil 24 is excited to generate an induced voltage, and if there is no object that disturbs the excitation field Φ, the induced voltages in each of the detection coils 26C, 27C, 28C, and 29C are balanced. The output signals VXI and VY1% of each detection coil 26C127C128C and 29C are held at 0 level.

Further, when the printed circuit boards 26, 27, 28 and 29 are stored in the storage case 30, the detection coils 26C and 27
The detection coil 2 is aligned so that the central axis O of C is orthogonal to the
The central axes O of 8C and 29C are arranged to be perpendicular to the Y direction.

Therefore, when an object that disturbs the excitation magnetic field Φ is placed on the plastic cover 32, each detection coil 26C, 2
When the object is located on the central axis O of 7C128C and 29C, each detection coil 26C127C128C and 2
At 9C, the induced voltage is maintained in a balanced state,
Output signal VXI, VX! , vVl, ■Y□ are held at 0 level.

On the other hand, an object that disturbs the excitation magnetic field Φ is
And when moving in the Y direction, each detection coil 26C, 27C,
At 28C and 29C, the balance of the induced voltage is lost, and the output signals VXI, vx! , ■□, the amplitude of vo changes.

In this way, the position information of the object that disturbs the excitation magnetic field Φ, the excitation coil 24 and each detection coil 26C, which change depending on the object,
The coupling degree of 27C, 28C and 29C is output signal V□,
It can be detected as amplitude information of VXts VYI, vo.

On the other hand, in the detection coils 26C and 27C,
Distance L with respect to the length L of one side that makes up the figure 8 shape
The detection coils 28C and 29C are arranged offset by a distance L/2 in the Y direction, whereas the detection coils 28C and 29C are arranged offset by a distance L/2 in the Y direction.

Therefore, when an object that disturbs the excitation magnetic field Φ is placed on the plastic cover 32, the detection coils 26C and 2
Based on the central axis O of 8C, if the distances in the X and Y directions from the central axis O to the object that disturbs the excitation magnetic field Φ are set as X and y, the detection coils 26C and 28 correspond to equation (1).
The output signals VXI and VYI of C are expressed by the following formula %... (3) y Vy+= Kg, ・5in(z ・-) sin
ωt... (4) On the other hand, the output signals of the detection coils 27C and 29C, ■X□ and vyz, can be expressed as 26C and 27C and detection coil 28
By arranging the detection coils 26C and 29C with a distance of L/2, the detection coils 26C and 29C are shifted by a distance L/2. When an object that disturbs the excitation M1 magnetic field Φ is displaced in the X and Y directions from the central axis O of the
The output signals Vx and v8□ of 2 & Il vary by degrees.
, V□ and VvzC (Fig. 3 (A) and (B)) can be obtained.

Incidentally, in this embodiment, pencil-shaped movable bodies 35A and 35B each having built-in series resonant circuits with resonance frequencies f1 and f2 are used as objects that disturb the excitation magnetic field Φ, and the tip of each movable body 35A and 35B is The resonant coils L1 and L2 (FIG. 5) of the series resonant circuit are arranged in this section, so that the resonant coils L1 and L2 are excited by the excitation coil 24.

Therefore, two sets of output signals ■8. and VXZ and ■, I and v
In yz, when the excitation coil 24 is driven by the sine wave drive signal SD of frequency f, the excitation magnetic field Φ is disturbed by the resonant coil L1 disposed on the movable body 35A, thereby causing resonance of the movable body 35A. Regarding the coil L1 (
3) to (6), whereas when the excitation coil 24 is driven by the sine wave drive signal SD of the frequency f2, the resonant coil L2 disposed on the movable body 35B
The excitation magnetic field Φ is disturbed, and the resonant coil L2 of the movable body 35B
The relationships expressed by equations (3) to (6) above are maintained for the equations (3) to (6).

As a result, when the movable bodies 35A and 35B are moved simultaneously on the plastic cover 32, the movable body 35A
and 35B and continuously detects their coordinate data so that handwritten characters can be input.

Furthermore, in this embodiment, the output signals V□, V 11
2% V Y l and ■y, each detection coil 26C1
When outputting from 27C128C and 29C, a land for connecting a lead wire is provided on one side of the printed circuit boards 26 to 29, and a twisted pair wire is connected to the land and drawn out, thereby outputting the output signal vXISvX1.
, VV- and the excitation magnetic field Φ for the lead wire of v7□
It is possible to input highly accurate coordinate data by effectively avoiding the influence of

In the two-dimensional coordinate data input device 10, the output signal v
xI and ■. is applied to amplifier circuits 40 and 42 for amplification, and then analog-to-digital conversion circuits (A/D) 44 and 4
6 to convert it into a digital signal, and at this time, the proportionality constants of the output signals VxI and VXt, and KI! The output signal V is corrected by the signal level of 2 via the level correction circuit 48 so that the values become equal.

This allows the analog-to-digital conversion circuits 44 and 46
Through equations (3) and (5), with 2 = and 2 =, the following formula VX3 = - 5in (π・) sin ωtL ...... (7) VX4 = K Icos ( z ・−) sin ωt・
...(8) Output signals VX3 and VX4 expressed as follows can be obtained.

On the other hand, the delay circuit 48 is constructed by connecting a predetermined number of stages of shift register circuits in series that operate based on the clock signal SCK, thereby delaying the output signal VX4 expressed by a sine function, and delaying the output signal VX4 expressed by the following equation. It is converted into an output signal VX4D expressed by the cosine function of the formula (9).

By the way, if the delay circuit is constructed of shift register circuits connected in series in a predetermined number of stages, the delay time can be switched according to the clock cycle.

Therefore, in this embodiment, since the frequency of the drive signal SD is switched by switching the clock frequency, the delay time of the delay circuit can be switched in accordance with the frequency of the drive signal SI1, and thus the frequency of the drive signal SD can be changed. Even when switching, the output signal VX4 can be converted to the output signal V expressed by a cosine function with a simple configuration and with high accuracy.
, D.

The subtraction circuit 50 outputs the output signal ■. By subtracting the output signal 4D from , the movable body 35 obtained as amplitude information is expressed as
The position information of A and 35B is converted into phase information.

That is, when the position information of the resonant coils L1 and L2 is directly detected from the amplitude information, the amplitude of the output signals VXI and VXZ of the detection coils 26C and 127C is the same as that of the movable bodies 35A and 35B.
If the location information changes due to factors other than location information, it becomes difficult to detect location information with high accuracy.

However, the amplitudes of the output signals VXI and VXZ also change depending on the degree of coupling between the detection coils 26C, 27C and the excitation coil 24. For example, a resonance coil connected to a resistor with a small resistance value at the resonance frequency f1, and a resonance coil connected to a resistor with a small resistance value at the resonance frequency f1, , and a resonant coil connected to a resistor with a large resistance value are used alternately, the output signals VXI and 2 have different amplitudes even though the resonant coils are placed at the same position. is obtained, and in this case it becomes difficult to detect overwhelming position information.

However, as in this embodiment, if the position information of the resonant coils L1 and L2 obtained as amplitude information is converted into phase information, the phase information can be held so as to change depending only on the position information, and the detection Even if the degree of coupling between the coil 26C127C and the exciting coil 24 changes, correct position information can be detected.

That is, since the subtraction signal S8 output from the subtraction circuit 50 has the position information of the resonance coils L1 and L2 as phase information, the drive signal So of the excitation coil 24
By obtaining a phase comparison result between the subtraction signal SX and the subtraction signal SX, it is possible to detect the positional information of the resonant coils L1 and L2.

In this way, the detection coils 26C and 27C are connected to the predetermined path 1jiI.
By arranging the detection coil 2 at a distance of L/2,
Two output signals VXI and V include position information based on 6C and 27C as amplitude information. can be obtained, and only the position information of the resonant coils L1 and L2 can be selectively extracted based on these two output signals v0 and VXZ.

Furthermore, in the amplitude of the subtraction signal SX, the detection coil 26
Since it changes only by the degree of coupling between C127C and the exciting coil 24, this relationship can be used to identify resonant coils connected to resistors with the same resonant frequency and different resistance values (i.e., at the resonant frequency f1 described above). In the two-dimensional coordinate data input device 10, the subtraction signal S
X is output to comparison circuits 52 and 54 to detect position W information in the X direction and identify the types of movable bodies 35A and 35B.

Here, the comparison circuit 52 receives reference data DIEF representing a signal level of 0 level. As a result, the subtraction signal SX
When the signal level rises from the O level, the comparison output signal SCO rises.

On the other hand, the flip-flop circuits (F/F) 56 and 57 are configured to function as an edge detection circuit together with the AND circuit 58, and when the comparison output signal SCOMM rises, the flip-flop circuits (F/F) 56 and 57 are connected for one clock period of the clock signal SCK. It is designed to drive a latch circuit 60.

On the other hand, the latch circuit 60 is configured to receive the address data DAII5 output from the address counter circuit 15, and thereby receives the drive signal S of the excitation coil 24.
! The address data I)Aoo whose value changes sequentially and cyclically in accordance with + is latched at the timing when the subtraction signal SX rises from the O level.

As a result, in the latch circuit 60, the excitation coil 24
When the phase of the subtraction signal S8 changes with respect to the drive signal S0, a latch result whose value changes according to the amount of phase can be obtained, and thus the phase comparison result with the drive signal S and the subtraction signal SX can be easily obtained. can be obtained.

Thus, in this embodiment, the latched address data is input to the control circuit 11 as X-direction coordinate data DX.

As a result, the control circuit 11 can detect the coordinate data of the resonant coils L1 and L2 resonating at the resonant frequencies SHI and FT, respectively, based on the clock frequency at the time of latching.
In this way, the movable bodies 35A and 35B can be identified and the coordinate data DX in the X direction can be input.

Therefore, coordinate data can be input simultaneously using the wireless movable bodies 35A and 35B, and usability and reliability can be improved accordingly compared to the conventional system.

On the other hand, the comparison circuit 54 uses predetermined comparison reference data D.
REF+ is received together with the subtraction signal SX, and comparison reference data D is received.
When the signal level of the subtraction signal SX rises above the signal level determined by IEFI, the signal level of the comparison output signal rises.

The retriggerable monomulti circuit 62 receives the comparison output signal of the comparison circuit 54 and includes a capacitor 63 and a semi-fixed resistor 64.
As a result, when the amplitude of the subtraction signal SX becomes greater than a predetermined value, the signal level of the output signal S MOD is switched.

As a result, for example, when using a resonant coil in which resistors with different resistance values are connected at the same resonant frequency f, f, in place of the resonant coils LL and L2, the detection coil 26C127
A change in the amplitude of the subtraction signal SX due to a change in the degree of coupling between C and the exciting coil 24 is detected, and an output signal S is generated. . The signal level can be changed.

Therefore, it is possible not only to simultaneously use the movable bodies 35A and 35B in which the resonant coils Ll and L2 are arranged, but also to input the coordinate data by selectively using a plurality of movable bodies in which the resonant coils with the same resonance frequencies f+ and fz are disposed. The usability of the two-dimensional coordinate data input device 10 can be improved by switching, for example, the display color, thickness, etc. of a handwritten line drawing depending on the type.

On the other hand, the amplifier circuits 64 and 66
After amplifying the output signals V□ and V2 of C and 29C,
The analog-to-digital conversion circuits 68 and 70 convert the signal into a digital signal, and at this time, the level correction circuit 69 corrects the signal level of the output signal (i).

This causes the output signals VXI and V to be output via the analog-to-digital conversion circuits 68 and 70. Similarly, output signals VY3 and VY4 expressed by the following formulas (11) ( (12) can be obtained.

On the other hand, the delay circuit 72 has the same configuration as the delay circuit 48, so that the output signal VY expressed by a sine function
4 is delayed and converted into an output signal VY4D expressed by a cosine function of the following formula % (1) (13).

The comparison circuit 74 determines that the signal level of the output signal VY3 is the output signal V,4. When the signal level rises above the signal level of , the signal level of the comparison output signal S coMv rises.

That is, in this embodiment, the coordinate data D8 in the X direction
To obtain this, subtraction signals S and l are created, and a tie in which the subtraction signal S8 rises from the O level is detected.

However, in reality, in the subtraction signal S8, the l output signal VX
Since it is created by subtracting the output signal ■□ゎ from 3, the signal level of the output signal VX3 is the output signal vX
By detecting the timing at which the subtraction signal SX rises from the 4D signal level, the process of creating the subtraction signal Sx can be omitted and the timing at which the subtraction signal SX rises from the O level can be detected, and the coordinate data can be detected with a correspondingly simpler configuration. can do.

Thus, when detecting coordinate data in the Y direction, the signal level of the output signal VV3 in the comparator circuit 74 is set to the output signal V.
The timing at which the signal rises above the signal level of Y2O is detected, thereby obtaining the coordinate data input device 10 with an overall simple configuration.

The flip-flop circuits 76 and 77 are connected to an AND circuit 78
A comparison output signal S, which together constitutes an edge detection circuit and is output from the comparison circuit 74. He was made to receive 87,
When the comparison output signal scoytv rises, the latch circuit 80 is driven by one clock period of the clock signal SCK.

As a result, address data D Aoo is latched and Y
Directional coordinate data DV can be detected.

Thus, the detection coil 26C127C128 has a pair of coils connected at a distance so as to cancel out the induced voltage.
C and 29C output signals VXt, VXZ, vvI and V
Resonant coils L1, L that disturb the excitation magnetic field Φ based on Vt
2 can be detected.

Therefore, the wireless movable body 35 that only disturbs the excitation magnetic field Φ
A and 35B can be used to input two-dimensional coordinate data, making it possible to improve usability and reliability compared to the conventional system.

Incidentally, in this embodiment, the address counter circuit 15,
The read-only memory circuit 17, the digital-to-analog conversion circuit 19, the amplifier circuit 21, and the level correction circuit 22 constitute a drive signal generation circuit that outputs the drive signal SD to the excitation coil 24, whereas the control circuit 11 and the clock signal generation circuit The circuit 12 constitutes a drive signal switching circuit that switches the frequency of the drive signal SD.

(G3-2) In the configuration described above, when an object that disturbs the excitation magnetic field is placed on the plastic cover 32, each detection coil 26C,
When the object is located on the central axis O of 27C, 28C, and 29C, the induced supervoltage is maintained in a balanced state in each detection coil 26C, 27C, 28C, and 29C, and the output signal vXI% vxz・VY1・VX' l is held at 0 level.

On the other hand, an object that disturbs the excitation magnetic field Φ is present in each detection coil 2.
When moving in the X and Y directions from the central axis O of 6C, 27C, 28C and 29C, each detection coil 26C127C128
The balance of the induced voltage is lost at C and 29C, and the moving distance x
, y, output signals V z 1 , V X z ,
The signal levels of V y I, V'ft change, and as a result, the position information of the object becomes output signals VXI, VX2, V
□, detected as amplitude information of vyt.

At this time, in the object that disturbs the excitation [i field Φ, the movable bodies 35A and 3 are equipped with resonance circuits with resonance frequencies f and ft.
5B and by switching the clock frequency at predetermined intervals to switch the frequency of the drive signal S, when the drive signal SD is held at the frequency f, the output signals V□, ■x7, V□, VVZ As the amplitude information of the movable body 3
5A, while the position information of the resonant coil L1 placed at the movable body can be detected as the amplitude information of the output signals VXt, V, , VY, , vyg when the drive signal SD is held at the frequency f2. Resonant coil L2 located at 35B
location information can be detected.

The output signals VX+, vllts VYI, Vvz are given to analog-to-digital conversion circuits 44.46.68 and 70 via amplifier circuits 40.42.64 and 66, respectively, and output signals VX3, vX4, and
■71, converted to VY4, level correction circuit 4
After the signal levels of the output signals VX4 and VY4 are corrected in steps 8 and 69, the output signals VX4 and VY4 are expressed by cosine functions in the delay circuits 4 and 72. is converted to

The output signals VX1 and V
Convert L2 position information to phase information.

The subtraction signal SX output from the subtraction circuit 50 is converted into reference data DI! representing a signal level of 0 level by the comparison circuit 52.
F. A comparison result is obtained, and the comparison output signal S, is obtained. □ is output to the latch circuit 60 via an edge detection circuit composed of flip-flop circuits (F/F) 56 and 57 and an AND circuit 58.

As a result, the address data DADD is latched at the timing when the subtraction signal SX rises from 0 level, the resonant coils L1 and L2 are identified based on the clock frequency, and the result of the phase comparison between the drive signal SIl and the subtraction signal SX is determined by the coordinate in the X direction. It is input as data Dx.

Further, the comparison circuit 54 obtains a comparison result of the subtraction signal SX with predetermined comparison reference data Ditr+, and the comparison output signal is outputted via the retriggerable monomulti circuit 62.

As a result, for example, when using a resonant coil in which resistors of different resistance values are connected at the same resonant frequency f or r2 instead of the movable body 35A or 35B, the detection coil 26C12
The signal level of the output signal 5NOD can be switched by detecting a change in the amplitude of the subtraction signal SX due to a change in the degree of coupling between 7C and the exciting coil 24.

On the other hand, the output signals VVS and VY4D are applied to a comparison circuit 74, which detects the timing at which the signal level of the output signal VYI rises from the signal level of the output signal V4D.

The comparison output signal SCO□ output from the comparison circuit 74 is
Flip-flop circuit 76.7-7 and AND circuit 78
The signal level of the output signal VVS is outputted to the latch circuit 80 via the edge detection circuit composed of the output signals (1), 4. The address data DADll is latched at the timing when the signal rises above the signal level of .

As a result, the process of creating a subtraction signal for the output signals VV2 and Y4D is omitted, and data representing the phase comparison result of the subtraction signal and the drive signal SD is latched in the latch circuit vr80, thereby obtaining coordinate data DV in the Y direction. be able to.

(G3-3) Effects of Example According to the above configuration, the detection coil 26C has a set of coils connected in a figure-eight shape so as to cancel out the induced voltage.
, 27C, 28C, and 29C at predetermined positions and excitation by switching the frequency with the excitation coil 24,
Each detection coil 26C, 2
7C.

The position information of the resonant coils L1 and L2 based on the center axis O of 28C and 29C is output as signals VX+, ■8□, and VY.
It can be detected as amplitude information of t and VYt.

The resonance coils L1 and L2 thus obtained as amplitude information
By inputting the phase comparison result with the drive signal SD of the excitation coil 24 based on the drive frequency of the excitation coil 24, the movable body 35A
and 35B can be identified and coordinate data can be input.

(G4) Other Embodiments In the above-mentioned embodiments, a case was described in which a detection coil was created using a wiring pattern and through holes on a printed circuit board, but the present invention is not limited to this. Alternatively, the detection coil may be formed by doing so.

Furthermore, in the above embodiment, eight rectangular coils are used.
Although the case has been described in which the detection coils are created so as to cancel the induced voltage by connecting them in a square shape, the present invention is not limited to this, but the present invention is not limited to this. On the circuit side, the coils may be connected so that the induced voltages of each coil cancel each other out.

Furthermore, in this case, after amplifying the induced voltage of each coil,
They may be added so as to cancel each other out, and furthermore, asymmetry of each coil shape, non-uniformity of excitation magnetic field Φ, etc. may be corrected.

Furthermore, in the above embodiment, eight rectangular coils are used.
Although the case has been described in which a detection coil is created by separating two coils so that one side of the coils overlaps by connecting them in a square shape, the present invention is not limited to this.
The separation distance can be freely selected depending on the required detection accuracy of coordinate data.

Furthermore, in the above-described embodiment, a case was described in which a detection coil was created by connecting rectangular coils with one turn. The number of coils can be widely applied.

In this case, the distance L with respect to the detection coils 26C and 28C
Detection coils 27C and 2 arranged with a shift of /2
9C may be configured as shown in FIG. 8, for example.

In other words, the coil 27C is moved to a position shifted by a distance L/2.
L (29CL) and coils 27CR on both sides.
(29CR) is divided and formed.

Incidentally, even if a detection coil formed in this way is used,
The same effects as in the first embodiment can be obtained.

In order to obtain a wider detection range while maintaining higher detection accuracy, a detection coil having a configuration as shown in FIG. 9 may be used.

That is, in the first detection coil 90, four rectangular coils each having a side length L are sequentially and alternately connected so that the induced voltages cancel each other out.

On the other hand, the second detection coil 91 has the same shape as the first detection coil 90, and is shifted from the first detection coil 90 by a distance L/2.

In this way, it is possible to obtain an output signal whose amplitude changes depending on the position of the movable body, with reference to the connecting portions 01.02 and 03 of each coil.

Therefore, by combining detection coils 90 and 91 with detection coils 92 and 93 that are twice the size,
Coordinate data can be detected over a wide range.

Furthermore, in the above embodiment,! Although the case where the jjJfff coil is driven with a sine wave signal has been described, the present invention is not limited to this, and various drive signals such as a rectangular wave signal and a triangular wave signal can be widely applied as necessary.

Further, in the above-described embodiment, a case has been described in which the drive signal SD is switched at the resonant frequencies f1 and f2 of the movable bodies 35A and 35B, but the present invention is not limited to this, and the third and fourth It may be possible to switch between the frequencies.

Furthermore, the frequency of the drive signal S0 is not limited to being switched stepwise, but the frequency of the drive signal S0 may be switched continuously, for example, by using a frequency modulation circuit as a clock signal control circuit.

In this way, a subtraction signal Sx whose signal level changes rapidly in the vicinity of the resonant frequencies f and f2 of the movable bodies 35A and 35B according to the sharpness Q of the resonance circuit of each of the movable bodies 35A and 35B is obtained. be able to.

Therefore, by detecting the change in this subtraction signal SX,
The sharpness Q may be detected and the movable bodies 35A and 35B may be indirectly identified based on the frequency of the drive signal S0 and the output signals of the detection coils 26C, 127C, 28C and 29C.

Furthermore, by doing this, it is possible to omit the comparator circuit 54 and the retriggerable monomulti circuit 62, and to identify a resonant coil in which resistors having the same resonant frequency and different resistance values are connected, thereby simplifying the overall u4 power. can be converted into

Further, in the above-described embodiment, a case was described in which a delay circuit was constructed by connecting shift register circuits in series, but the present invention is not limited to this, and a delay circuit may be constructed using a memory circuit. .

Furthermore, in the embodiment described above, the output signals VX4 and V
Although the case where y4 is delayed has been described, the present invention is not limited to this, and the output signals VX3 and vo may be delayed.

Further, in the above-described embodiment, a case has been described in which the output signal of the detection coil is converted into a digital signal and processed, but the present invention is not limited to this, and the analog signal may be processed as it is.

In other words, the output signals V□, ■X□, V v r Fh bi■
After amplifying Vt, the phase circuit outputs the output signals ■, and ■□,
Alternatively, the phases of output signals VXt and vv□ are delayed by 90 degrees.

Furthermore, the output signal of the phase circuit and the output signal vM2 and Vtl
, or after creating a subtraction signal with the output signal ■□ and Vt'+, address data is latched at the timing when the subtraction signal rises from the 0 level.

Alternatively, after the signal level of the subtraction signal is corrected to a predetermined reference value, a phase comparator may be used to compare the phase with the excitation coil drive signal.

In this way, the output voltage of the phase comparator can be changed according to the position of the movable body, and thereby the coordinate data of the movable body can be input.

In the above-described embodiment, a case was described in which address data is latched at the timing when the subtraction signal rises from the 0 level, but the present invention is not limited to this.
When latching the song address data, the amplitude of the subtraction signal is corrected to a predetermined value, and then the address data is set at the timing when the corrected signal rises or falls to the predetermined signal l/bell. In addition, the address data may be latched at the timing when the subtraction signal rises or falls to a predetermined signal L/bell corresponding to the peak value of the subtraction signal.

Furthermore, in the above embodiment, a case was described in which a pencil-shaped movable body having a series resonant circuit connected to a resistor was used, but the shape of the movable body is not limited to this, and various shapes can be applied. can.

Furthermore, the resistor may be omitted at this time.

Furthermore, in the above-mentioned embodiment, a case was described in which two-dimensional coordinate data was input, but the present invention is not limited to this.
It can also be widely applied when inputting one-dimensional coordinate data.

Further, in the above-described embodiment, a case where handwritten characters are manually input is described, but the present invention is not limited to this, and the present invention is not limited to this, but the present invention is also applicable to inputting various coordinate data instead of conventional coordinate data input means, such as when inputting a figure. It can be widely applied in cases.

H Effects of the Invention As described above, according to the present invention, the magnets are arranged at a predetermined distance apart and are excited by switching the frequency.
By arranging the m coils at predetermined intervals, it is possible to identify the movable body and input coordinate data based on the differential voltage of each set of coils and the frequency of the excitation magnetic field.

In this way, it is possible to input coordinate data using a plurality of wireless movable bodies at the same time, and it is possible to obtain an input device with improved usability and reliability compared to the conventional one.

Furthermore, according to the second invention, by providing a resonant circuit in the movable body, the movable body can be identified based on the resonant frequency of the resonant circuit, and thus a plurality of movable bodies can be used simultaneously or alternately to determine the coordinates. An input device can be obtained into which data can be input.

[Brief explanation of drawings]

1 and 2 are route maps for explaining the position detection principle of the present invention, FIG. 3 is a signal waveform diagram for explaining the principle, and FIG.
5 and 5 are connection diagrams for explaining the principle of identifying objects that disturb the excitation magnetic field, FIG. 6 is a block diagram showing a two-dimensional coordinate data input device according to an embodiment of the present invention, and FIG. 7 is a diagram showing the tablet. The perspective view shown, FIGS. 8 and 9 are route maps showing other embodiments. ■, 24... Excitation coil, 4.5.26CR1
26CL, 27CR, 27CL, 28CR, 28CL,
29CR, 29CL... Coil, 10...
... Two-dimensional coordinate data input device, 15 ... Address counter circuit, 17 ... Read only memory circuit, 26C, 27C128C, 29C ...
Detection coil, 34... Tablet, 35...
...Movable body, 48.72...Delay circuit, 50
・・・・・・Subtraction circuit, 52.54.74・・・・・・
Comparison circuit, 60.80...Latch circuit.

Claims (2)

[Claims] (1) An excitation coil that generates a predetermined excitation magnetic field, and first and second coils that are arranged at a predetermined distance apart and that are excited by the excitation coil and generate an induced voltage, and that are separated by a predetermined distance. are arranged in the arrangement direction of the first and second coils, are excited by the excitation coil to generate an induced voltage, and are arranged at predetermined intervals with respect to the arrangement positions of the first and second coils. The first and fourth coils include third and fourth coils arranged to shift, a drive signal generation circuit that outputs a drive signal to the excitation coil, and a drive signal switching circuit that switches the frequency of the drive signal. on the first and second coils and the third and fourth coils based on the difference voltage between the induced voltages of the second coil and the third and fourth coils. An input device characterized in that the coordinate data of a placed movable body is detected and the movable body is identified based on the frequency of the drive signal. (2) The movable body includes a resonant circuit that connects a capacitor and a coil excited by the excitation magnetic field and resonates at a predetermined frequency of the drive signal. Input device as described.