JPH05289807A - Coordinate input device - Google Patents

Abstract

PURPOSE:To detect many switches in a cordless coordinate input device. CONSTITUTION:A coordinate input device main body is provided with an exciting signal switch circuit 5, and one axis S1 of a sense line group 1 can be excited by plural frequencies, and a coordinate pointer 20 is provided with resonance frequency setting element groups 21 and 22 which change the resonance frequency of a resonance circuit in accordance with depression of a switch to resonate it to one of plural exciting frequencies and slightly shift the resonance frequency. The main body is provided with a circuit 8, which detects the phase difference between the induction signal from the coordinate pointer 20 and the exciting signal, to detect the depressed switch out of many switches in accordance with the exciting frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordless coordinate input device to which an electromagnetic induction phenomenon is applied, and more particularly to a coordinate input device capable of detecting operation states of a large number of switches provided on a coordinate indicator. ..

[0002]

2. Description of the Related Art As a method for detecting a switch state of a coordinate indicator in a conventional cordless coordinate input device, infrared rays are used to transmit a switch signal, or a resonance circuit whose resonance frequency is shifted is resonated and its phase is resonated. A method for detecting the amount of deviation has been proposed.

Regarding the method of detecting the position of the coordinate indicator, the invention proposed by the present applicant prior to this application (hereinafter referred to as the prior application 1) allows the cable to be removed from the coordinate indicator. it can. To briefly explain the present invention, one of the two sense line groups laid along each of the XY orthogonal coordinate axes is sequentially excited by an exciting circuit, and a resonance circuit that resonates with this exciting signal. When the coordinate indicator having the is closer to the sense line, the induction signal induced in the other sense line group is sequentially processed by the signal processing circuit, and the position of the coordinate indicator, that is, the coordinate is calculated from the magnitude of the processed induction signal. It's something I asked for.

[0004]

A device which transmits a switch signal using infrared rays has directivity,
There is a problem that the coordinate indicator itself requires a transmitter and a large-capacity battery, and the structure is complicated, heavy and large, and the operability deteriorates. Further, in detecting a large number of switch operations based only on the amount of phase shift, stable detection cannot be performed because the difference in phase data between the switches is small.

An object of the present invention is to provide a coordinate input device capable of detecting a large number of switch states and having good operability.

[0006]

In order to solve the above-mentioned conventional problems, the first structure has a plurality of sense lines parallel to one of the XY orthogonal coordinate axes and laid at equal intervals. A first sense line group, a second sense line group having a plurality of sense lines parallel to the other axis and laid at equal intervals to each other, and a first sense line group that sequentially selects the first sense line group. Of the plurality of excitation signals, which are connected to the first scanning circuit and the excitation means, and the excitation means for outputting excitation signals of a plurality of frequencies.
Connected to the second scanning circuit, a switch circuit for selecting one of them and supplying the selected excitation signal to the first scanning circuit, a second scanning circuit for sequentially selecting the second sense line group, A phase detection circuit for detecting a phase difference between the induction signal induced in the second sense line group and the excitation signal;
A coordinate input device main body having a control circuit that determines the pressed switch of the coordinate indicator from the phase difference signal detected by the phase detection circuit and the excitation frequency, a resonance circuit including a coil and a capacitor, and a switch. By being connected in response to the depression of, it becomes possible to resonate with each of the excitation signals of the plurality of frequencies, and at each resonance frequency, a resonance frequency setting element group provided so as to slightly shift the resonance frequency, A coordinate input device is configured by a coordinate indicator having a.

A second configuration is connected to the first scanning circuit and an excitation means for outputting excitation signals of a plurality of frequencies, adds the plurality of excitation signals, and supplies the addition to the first scanning circuit. A circuit, a frequency discriminating circuit connected to the second scanning circuit and discriminating the frequency of an induction signal induced in the second scanning circuit, and frequency information from the frequency discriminating circuit, The coordinate input device main body is configured such that a switch circuit that selects an excitation signal having the same frequency as the induction signal and the phase detection circuit are connected to the switch circuit and the frequency discrimination circuit.

[0008]

In the coordinate input device having the first structure, the resonant circuit of the coordinate indicator resonates due to the alternating magnetic field generated from the first sense line group, and the resonant circuit generates from the resonating coordinate indicator in the second sense line group. The induced signal is induced by the alternating magnetic field. At this time, the phase of the induction signal is shifted by slightly shifting the resonance frequency of the coordinate indicator.

First, one of the first sense line groups is excited at the first frequency and it is confirmed whether or not an induction signal is generated.
If an induction signal is generated, after the position of the coordinate indicator is obtained, the control circuit selects the sense line closest to the position of the coordinate indicator by the scanning circuit, and the amount of phase shift between the induction signal and the excitation signal at that time. To detect. At this time, the resonance circuit in the resonance state has the first selected according to the switch state.
Since any one of the resonance frequency setting element groups is connected, the detected phase shift amount is determined by the state of the switch circuit.

When the induction signal is not generated, excitation is similarly performed at another frequency, the position of the coordinate indicator is obtained from the induction signal, and the amount of phase shift between the induction signal and the excitation signal at that time is detected. This shift amount is also determined by the state of the switch circuit. In this way, by adjusting so that several types of switch states can be detected stably from the amount of phase shift at one frequency, multiple frequencies are used, and information on the resonant frequency and information on the phase difference data are used. Therefore, it becomes possible to stably detect the states of many switch circuits.

Further, in the coordinate input device having the second structure, the excitation signals of a plurality of frequencies are added to excite the first sense line group, so that the resonance circuit of the coordinate indicator can be operated in accordance with the state of the resonance circuit. An induction signal can be obtained without switching the excitation frequency, and the detection time can be shortened.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a configuration diagram of the coordinate input device according to the first configuration. In the figure, 1 indicates a sense line group, S1
Is a first sense line group having sense lines y1 to yn, S2 is a second sense line group having sense lines x1 to xm, 2 is a first scanning circuit for sequentially selecting the first sense line group S1, Reference numeral 3 is a second scanning circuit for sequentially selecting the second sense line group S2, 4 is an exciting circuit for exciting the first sense line group S1, 5 is a switch circuit for switching exciting signals of different frequencies, and 6 is an input. The frequency dividing circuit divides the frequency-divided signal to supply an exciting signal having a different frequency to the switch circuit, 7 an oscillation circuit supplying a basic signal to the frequency dividing circuit, and 8 a second sense line group S2. A phase detection circuit that detects the phase difference by comparing the phases of the induction signal and the excitation signal, 9 is a control circuit composed of a general CPU circuit, 10 is a signal storage circuit that stores the digitized phase difference signal, 20 Is Shows the target indicator 21 is constituted by a coil and a capacitor, configured resonant circuit to resonate the first excitation frequency, 21 ₁ to 21 ₆ is first energized by being connected to the resonant circuit 21 A first resonance frequency setting element group, 22 _{1 to} 22 ₆ , which configures a resonance circuit so as to resonate at a frequency and further changes the resonance frequency of the resonance circuit little by little, is connected to the resonance circuit 21 to generate a resonance frequency. To configure a resonance circuit so that the resonance circuit can resonate at the second excitation frequency, and to change the resonance frequency of the resonance circuit little by little, 23 is composed of a large number of switches. It is a switch unit that connects the first and second resonance frequency setting element groups to the resonance circuit 21 in response to pressing.

FIG. 2 is a detailed block diagram of the first scanning circuit 2. The same symbols as those in FIG. 1 indicate the same components as in FIG. 30 is a decoder, 31 is a switch element 31 _{1 to} 3
Analog switch group having 1n, 101 is excitation circuit 4
2 is an excitation signal output from the control circuit 9, and 102 is a selection signal output from the control circuit 9. Although details of the second scanning circuit 3 are not shown, the second scanning circuit 3 has the same configuration as that of the first scanning circuit 2 and is different in that the excitation signal 101 is input to the first scanning circuit 2. The second scanning circuit 3 outputs the guidance signal 104.

FIG. 3 is a detailed block diagram of the phase detection circuit 8. 40 is an amplification circuit, 41 is a waveform shaping circuit, and 42 is an EX
-OR circuits, 43 and 44 are resistors and capacitors, respectively, which form an integrating circuit. 45 is an A / D converter. Reference numeral 101 is an excitation signal, 104 is an induction signal from the second scanning circuit 3, and 105 is a phase difference signal output to the control circuit 9.

FIG. 4 is a waveform diagram of each signal. FIG. 5 is a perspective view of an embodiment of the coordinate indicator. The operation of this embodiment will be described below. In FIG. 1, the case where the coil forming the resonance circuit 21 of the coordinate indicator 20 is located at the intersection (section A in FIG. 1) of the sense line x4 and the sense line y4 will be described. The oscillator circuit 7 oscillates at a fundamental frequency of 1.2288 MHz, and the frequency divider circuit 6 divides the signal by 2 and 4 to 614.4 kHz.
z, 307.2 kHz clock signal to switch circuit 5
Is being supplied to. First, the control circuit 9 outputs the control signal 1
The switch circuit 5 is controlled by 00 to supply a signal of 614.4 kHz as the first excitation signal to the excitation circuit 4.
The excitation signal 101 (614.4 kHz) is output from the excitation circuit 4.
Is supplied to the first scanning circuit 2.

The first scanning circuit 2 selects any one of the first sense line groups S1 and generates an alternating magnetic field by the excitation signal from the selected sense line. At this time, when the resonance circuit 21 of the coordinate indicator 20 resonates with the excitation signal, an induction signal is induced in the resonance circuit 21 if the resonance circuit 21 of the coordinate indicator is present near the selected sense line. It Further, an induction signal is generated in any of the second sense line groups near the resonance circuit 21.

Therefore, first, a case where an induction signal is generated by the first excitation signal will be described. Coordinate indicator 2
The position of 0 is detected by the method of the prior application 1, and the selection signal 102 from the control circuit 9 causes the first scanning circuit 2 to move to the first scanning circuit.
The sense line y4 of the sense line group S1 is selected.
Further, the selection signal 103 from the control circuit 9 causes the second scanning circuit 3 to select the sense line x4 of the second sense line group S2.

[0018] That is, the decoder 30 in FIG. 2 is an analog switch 31 ₄ is turned on by the selection signal 102, the excitation signal 101 from the excitation circuit 4 (614.4KH
The sine wave of z) supplies the excitation signal 101 to the sense line y4 of the first sense line group via the first scanning circuit 2 to generate a magnetic field of 614.4 kHz from the sense line y4. At this time, since the resonance circuit 21 of the coordinate indicator 20 is configured to resonate at the frequency of the first excitation signal, an induction signal of 614.4 kHz is induced in the resonance circuit 21. Further, the induction signal of the resonance circuit 21 generates an induction signal in the second sense line group S2 near the resonance circuit 21. On the other hand, the second scanning circuit 3
Is the sense line x4 of the second sense line group in response to the selection signal 103 from the control circuit 9 similarly to the first scanning circuit.
Is selected, and the induction signal 104 from the resonance circuit 21 of the coordinate indicator 20 guided to the sense line x4 is supplied to the phase detection circuit 8.

Next, the operation of the phase detection circuit 8 will be described with reference to FIGS. First, the induction signal 104 to the sense line x4 is amplified by the amplification circuit 40, and the waveform shaping circuit 41 shapes the waveform into a rectangular wave like the induction signal 120 in FIG. Then, the EX-OR circuit 42 performs phase comparison between the waveform-shaped induction signal 120 and the excitation signal 101, and a phase difference signal 121 corresponding to the phase shift amount is obtained. The phase difference signal 121 is transferred to the resistor 43 and the capacitor 44.
Is integrated by an integration circuit consisting of
It is binarized by the / D converter 45. The binarized phase difference signal 105 is taken into the control circuit 9 and stored in the signal storage circuit 10 together with the frequency information of the excitation signal.

The potential of the phase difference signal 105 at this time is determined by a slight difference between the resonance frequency of the resonance circuit 21 of the coordinate indicator 20 and the frequency of the excitation signal 101. That is, it is determined by which one of the first resonance frequency setting element groups 21 _{1 to} 21 ₆ is connected to the resonance circuit 21 in response to the depression of the switch section 23 of the coordinate indicator 20.

Next, the case where the induction signal is not generated by the first excitation signal will be described. The control circuit 9 controls the switch circuit 5 by the control signal 100,
A signal of the second excitation signal 307.2 kHz is supplied to the excitation circuit 4. The excitation signal 101 (307.
(2 sine wave of 2 kHz) is supplied to the first scanning circuit 2, the position of the resonance circuit 21 of the coordinate indicator 20 is detected again by the method of the prior application 1, and the control circuit 9 uses the selection signals 102 and 103 to output the first signal. Control the scanning circuit 2 and the second scanning circuit 3 to select the sense line closest to the position of the resonance circuit 21 of the coordinate indicator 20 from the first and second sense line groups S1 and S2. .. The resonance circuit 21 of the coordinate indicator 20 is selectively connected to any of the second resonance frequency setting element groups 22 _{1 to} 22 ₆ so as to resonate at the frequency of the second excitation signal. 3 for 21
An induction signal of 07.2 kHz is induced.

Further, the induction signal of the resonance circuit 21 generates an induction signal in the second sense line group S2 near the resonance circuit 21, and the induction signal 104 is supplied to the phase detection circuit 8 to detect the phase. The circuit 8 can obtain a phase difference signal from the binarized second excitation signal as in the operation at the first excitation frequency. The phase difference signal is taken into the control circuit 9 and stored again in the signal storage circuit 10 together with the frequency information of the excitation signal.

The potential of the phase difference signal 105 at this time is
As in the case of the first excitation frequency, the coordinate indicator 20
Of the resonance frequency of the resonance circuit 21 and the second excitation signal 101
It is determined by the difference from the frequency. That is, the coordinate finger
When the switch unit 23 of the indicator 20 is pressed, the resonance
The circuit 21 includes a second resonance frequency setting element group 22₁~ 22 ₆
Of which is connected.

The control circuit 9 includes the signal storage circuit 10
The pressed switch number can be determined based on the phase difference signal stored in and the frequency of the excitation signal at that time. Figure 6
FIG. 6 is a configuration diagram of a coordinate input device having a second configuration. In the figure, 11 is an adder circuit for adding the excitation signals of a plurality of frequencies from the frequency dividing circuit 6, shaping the plurality of excitation signals into a sine wave, and supplying the added excitation signals to the excitation circuit 4,
The added excitation signal 101 is supplied from the excitation circuit 4 to the first scanning circuit 2, and a magnetic field is generated from the first sense line group S1. Reference numeral 12 is a frequency discrimination circuit for discriminating the frequency of the induction signal 104 induced by the second scanning circuit 3, which outputs the frequency identification signal 106 to the control circuit 9 and supplies the induction signal to the phase detection circuit 8. Reference numeral 13 is a switch circuit, which inputs the excitation signals of a plurality of frequencies from the frequency dividing circuit 6,
An excitation signal having the same frequency as the induction signal is supplied to the phase detection circuit 8 according to a control signal from the control circuit 9.

The operation of this embodiment will be described below. In FIG. 6, as in the case of FIG. 1, the case where the coil forming the resonance circuit 21 of the coordinate indicator 20 is located at the intersection (section A in FIG. 6) of the sense line x4 and the sense line y4 will be described. . Oscillator circuit 7 has a basic frequency of 1.2
It oscillates at 288 MHz, and the frequency dividing circuit 6 divides the signal by 2 and 4 to 614.4 kHz and 30 respectively.
The excitation signal of 7.2 kHz is supplied to the adding circuit 11. The adder circuit 11 adds the plurality of excitation signals and supplies them to the excitation circuit 4. An excitation signal 10 is output from the excitation circuit 4.
1 (a signal obtained by adding a sine wave of 614.4 kHz and a sine wave of 307.2 kHz) is supplied to the first scanning circuit 2. Similar to the first configuration, the first scanning circuit 2 allows
Y4 of the first sense line group S1 adjacent to the coordinate indicator 20 is selected, and an alternating magnetic field is generated by the excitation signal from the selected sense line. Since the alternating magnetic field is a magnetic field obtained by adding a plurality of excitation signals, the resonance circuit 21 of the coordinate indicator 20 resonates with the excitation signals, and an induction signal (614.4 kHz) is induced.

Further, the induction signal of the resonance circuit 21 generates an induction signal in the second sense line group S2.
The second scanning circuit 3 controls the control signal 103 from the control circuit 9.
Thus, X4 of the second sense line group S2 adjacent to the coordinate indicator 20 is selected and the induction signal is supplied to the frequency discrimination circuit 12. The frequency discriminating circuit 12 discriminates the frequency component of the induction signal, outputs the frequency discrimination signal 106 to the control circuit 9, and supplies the induction signal to the phase detection circuit 8. The control circuit 9 controls the frequency identification signal 10
6, the switch circuit 13 is controlled to select an excitation signal having the same frequency as the induction signal from the plurality of excitation signals from the frequency dividing circuit 6 and output it to the phase detection circuit 8. The phase detection circuit 8 compares the phase of the induction signal with the excitation signal from the switch circuit 13 and outputs a phase difference signal 105 to the control circuit 9. The control circuit 9
The phase difference signal and the frequency identification signal are stored in the signal storage circuit 10.

At this time, the potential of the phase difference signal 105 is the first
Similarly to the case of the invention of FIG.
Corresponding to the pressing of 3, the resonance circuit 21 has a first resonance frequency
Setting element group 21₁~ 21₆Which one was connected
Is decided. Next, the resonance circuit of the coordinate indicator 20.
21 is a second resonance frequency setting element group 22 ₁~ 22₆Noi
Explaining the case where the gap is connected,
From Y4 of the sense line group S1 of
Since the added magnetic field is generated, the coordinate indicator 20
In the resonance circuit 21, the second resonance frequency setting element group 221 to
Resonance and induction if any of 226 is connected
The signal (307.2 kHz) is induced.

Then, an induction signal is generated in the second sense line group S2. The induction signal is supplied to the frequency discriminating circuit 12 via the second scanning circuit 3. The frequency discriminating circuit 12 discriminates the frequency of the induction signal 104, outputs a frequency identification signal 106 to the control circuit 9, and supplies the induction signal to the phase detection circuit 8. The control circuit 9 controls the switch circuit 13 based on the frequency identification signal 106,
An excitation signal having the same frequency as the induction signal is output to the phase detection circuit 8. The phase detection circuit 8 compares the phases of the excitation signal and the induction signal having the same frequency as the induction signal from the switch circuit 13, and the phase difference signal 105 corresponding to the amount of phase deviation is obtained. The control circuit 9
Is a signal storage circuit 1 for storing the phase difference signal and the frequency identification signal.
Store in 0.

The control circuit 9 can determine the number of the pressed switch based on the phase difference signal stored in the signal storage circuit 10 and the frequency identification signal of the induction signal. Further, in the above embodiment, the basic signal of the oscillation circuit 7 is 1.2288 MH.
z, 1/2 and 1/4 are used as the frequency division ratio of the frequency dividing circuit, and a sine wave is used as the excitation signal, but the frequency, the frequency division ratio, the frequency division number, and the waveform are limited to these. Not.

Further, although the capacitor has been described as the embodiment as the element for shifting the resonance frequency in the coordinate indicator,
The same effect can be obtained even if the resistor is used.

[0031]

As described above, according to the first configuration, when the exciting circuit excites the sense line group laid along one of the XY Cartesian coordinate axes, a switch circuit is added between them to form a plurality of switches. And a coordinate indicator that has a resonance circuit that can resonate with a plurality of excitation signals and that can slightly shift the resonance frequency for each frequency in response to pressing each switch. By doing
If the phase detection circuit of the main body of the coordinate input device can stably detect 6 types of phase difference signals at one frequency, it is possible to stably detect 12 types of phase difference signals by using two frequencies. As a result, the multi-switch coordinate indicator, which was used in the conventional coordinate input device, can be realized without a cord.

Further, according to the second configuration, when the exciting circuit excites the sense line group laid along one of the XY orthogonal coordinate axes, an adding circuit is added between them to generate an exciting signal of a plurality of frequencies. It is possible to excite with a signal that has been added, and a frequency discriminating circuit is added before the phase detection circuit to identify the frequency of the induction signal. The time can be greatly reduced.

Therefore, when the operator uses the coordinate indicator on the coordinate input device, it is possible to provide a coordinate input device having good operability, which does not limit the movement of the coordinate indicator at all. Further, there is no failure due to the disconnection of the cable between the coordinate input device main body and the coordinate indicator, which is one of the drawbacks of the conventional coordinate input device, and the reliability of the coordinate input device can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a coordinate input device of the present invention.

FIG. 2 is a detailed configuration diagram of a scanning circuit.

FIG. 3 is a detailed configuration diagram of a phase detection circuit.

FIG. 4 is a waveform diagram of each signal.

FIG. 5 is a perspective view of a coordinate indicator of the present invention.

FIG. 6 is a configuration diagram showing another embodiment of the coordinate input device of the present invention.

[Explanation of symbols]

 1 Sense Line Group 2 First Scanning Circuit 3 Second Scanning Circuit 4 Excitation Circuit 5 Switch Circuit 6 Frequency Division Circuit 7 Oscillation Circuit 8 Phase Detection Circuit 9 Control Circuit 10 Signal Storage Circuit 11 Addition Circuit 12 Frequency Discrimination Circuit 13 Switch Circuit 20 coordinate indicator 21 resonant circuit 23 switch section

Claims (2)

[Claims] 1. A coordinate input device including a coordinate input device main body and a coordinate indicator, wherein the coordinate input device main body is a plurality of parallel to one of the XY orthogonal coordinate axes and laid at equal intervals. First with a sense line
Sense line group, a second sense line group having a plurality of sense lines parallel to the other axis and arranged at equal intervals, an exciting means for outputting an exciting signal of a plurality of frequencies, and the exciting means. A switch circuit connected to the means, selecting one of the excitation signals of the plurality of frequencies, and supplying the selected excitation signal to the first sense line group, and a switch circuit induced to the second sense line group. Induction signal and the first
A phase detection circuit for detecting a phase difference from the excitation signal supplied to the sense line group, and a phase difference signal detected by the phase detection circuit and information on the excitation signal supplied to the first sense line group. A switch determination circuit for determining a pressed state of a switch provided in the coordinate indicator, wherein the coordinate indicator includes a coil and a capacitor and resonates with one excitation signal of the excitation signals of the plurality of frequencies. A possible resonance circuit, and a plurality of resonance frequency setting element groups that are connected to the resonance circuit when the switch is pressed down and that can resonate the resonance circuit with one of the plurality of excitation signals. In the resonance frequency setting element group that can resonate, each resonance frequency setting element is set differently so as to slightly change the resonance frequency. Coordinate input apparatus characterized by being constituted by a number set element group. 2. A coordinate input device comprising a coordinate input device main body and a coordinate indicator, wherein the coordinate input device main body is a plurality of parallel to one of the XY orthogonal coordinate axes and laid at equal intervals. First with a sense line
Sense line group, a second sense line group having a plurality of sense lines parallel to the other axis and arranged at equal intervals, an exciting means for outputting an exciting signal of a plurality of frequencies, and the exciting means. Means for adding the excitation signals of the plurality of frequencies and supplying the added excitation signals to the first sense line group; and the frequency of the induction signal induced in the second sense line group. A frequency discriminating circuit for identifying the frequency discriminating circuit, and frequency information from the frequency discriminating circuit to select an exciting signal having the same frequency as the inducing signal induced in the second sense line group from the exciting signals having the plurality of frequencies. A switch circuit, a phase detection circuit for detecting a phase difference between an induction signal induced in the second sense line group and an excitation signal selected by the switch circuit, and the phase detection circuit The coordinate indicator is composed of a coil and a capacitor, which is composed of a switch determination circuit that determines the pressed state of a switch provided in the coordinate indicator from the detected phase difference signal and the frequency information from the frequency discrimination circuit. One of the excitation signals of the plurality of frequencies
A resonance circuit that can resonate with the excitation signal and a plurality of resonance frequency setting element groups that are connected to the resonance circuit by pressing a switch and that can resonate the resonance circuit with one of the excitation signals having the plurality of frequencies. In the resonance frequency setting element group that can resonate with the same excitation signal, each resonance frequency setting element is different from each other and is set so as to slightly change the resonance frequency. A coordinate input device comprising: