JPH0738150B2 - Position indicator in coordinate input device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position indicator of a coordinate input device capable of transmitting operating states of a plurality of switches.

(Prior Art) In a position indicator in a conventional coordinate input device, along with a coordinate position on the tablet of the position indicator, a state of which switch among a plurality of switches in the position indicator is operated (hereinafter, This is called the switch operation state.)
Is transmitted to the processor via a code or by a radio signal such as an ultrasonic wave, an ultraviolet ray or an alternating magnetic field.

(Problems to be Solved by the Invention) However, in the position indicator, the cord interferes with its movement, is broken due to fatigue, is a transmitter including an oscillation circuit of ultrasonic waves, ultraviolet rays, or an alternating magnetic field, and its power source. Since the battery to be used made the position indicator heavy, and the battery had to be charged and replaced,
There was a problem that operability and maintainability were not good.

It is an object of the present invention to provide a position indicator that can transmit the operating states of a plurality of switches without the need for a cord or a battery.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention is used in a coordinate input device to indicate a position to be measured to a tablet and operate any one of a plurality of switches. A position indicator for transmitting a state of whether or not the plurality of switches are tuned to the radio waves transmitted from the tablet, the tuning circuit having a plurality of different tuning frequencies configured by operating each of the plurality of switches. A position indicator in a coordinate input device is proposed in which a change in tuning frequency based on the operation of each switch is transmitted by radio waves reflected from the tuning circuits having different tuning frequencies to the tablet.

(Operation) According to the present invention, when any one of the plurality of switches is operated, a tuning circuit corresponding to the switch is formed. The tuning circuit reflects the radio wave transmitted from the tablet of the coordinate input device. However, since the tuning circuits have different tuning frequencies, the frequency of the reflected radio wave also differs for each tuning circuit, and the frequency of the switch operated by this tuning circuit changes. The state is transmitted.

(Embodiment) FIG. 1 shows an embodiment of a position indicator of the present invention, for example, an input pen 1, which includes a magnetic generator for position specification corresponding to a coordinate input device described later, for example, a bar magnet 11, It incorporates two sets of tuning circuits 12a and 12b including a coil and a capacitor.

More specifically, the input pen 1 has a core body 14 such as a ballpoint pen and a through hole capable of slidably accommodating the core body 14 inside a pen shaft 13 made of a non-metallic material such as synthetic resin. The bar magnet 11 provided, the coil spring 15, and the switches 121a and 121
b, a coil 122 with an iron core, two capacitors 123a, 123b, and two sets of tuning circuits 12a, 12b consisting of two variable capacitors 124a, 124b for fine adjustment are integrally combined and built in, and then A cap 16 is attached to the end.

The switch 121a is adapted to be turned on when the core body 14 is pushed into the pen shaft 13 by pushing the tip end of the core body 14 against the tablet surface, for example, by the rear end of the core body 14 via the coil spring 15. And switch 121b is a switch
When 121a is turned on, a signal is separately sent to the host computer each time it is turned on by the pushing operation, and, for example, color switching, painting of a certain portion, or the like is designated according to the number of times. Further, as shown in FIG. 3, the capacitor 123a and the variable capacitor 124a are connected in parallel with each other, one end of the coil 122 is connected to the other end thereof through the switch 121a, and the other end thereof is connected to the coil. The other end of 122 is connected to form one parallel resonant circuit 12a. And the capacitor 123b, the variable capacitor 124b,
The coil 122 and the switch 121b are similarly connected, and in this case, when the switches 221a and 121b are both turned on, another parallel resonant circuit 12b is configured.

The resonance circuit 12a is in phase with the radio wave transmitted from the antenna coil described later and resonates (tunes) to that frequency.
Then, the resonance circuit 12b is adjusted and set to resonate with these 180 ° phase differences. Resonant circuit 12a, 12b
By the above setting of, the selectivity Q = R / (ω0L) (where ω
0 is the resonance angular velocity, R is the resistance value of the resonance circuit, and L is the inductance), and a phase shift occurs. At the same time, the resonance frequency also changes, but resonance is possible.

FIG. 2 shows an example of the coordinate input device using the above-mentioned input pen 1. In the figure, 2 is a tablet, 3 is a position detection circuit, and 4 is a timing control circuit.

The tablet 2 has a non-magnetic metal casing 21 and a tablet body.
22 and an antenna coil 23 are housed, the tablet body 22 is connected to the position detection circuit 3, and the antenna coil 23 is connected to the timing control circuit 4.

The tablet body 22 constitutes a detection unit that is driven by the position detection circuit 3 to detect the position designated by the input pen 1, and the tablet body 22 is arranged substantially at the center of the housing 21. A frame 24 drawn on the top panel 21a of the housing 21 shows the coordinate input range.

Examples of the tablet body 22 and the position detection circuit 3 include, for example, Japanese Patent Application No. 58-238532 “Coordinate position detection device” (see Japanese Patent Application Laid-Open No. 60-129616) or Japanese Patent Application No. 59- 33083, "Position detecting device (Japanese Patent Laid-Open No. 60-176
No. 134) can be used. In the former case, a large number of magnetostrictive transmission media which are parallel to the surface of the tablet body 22 and orthogonal to each other are arranged, and magnetostrictive vibrations are propagated periodically from one end to the other end of the input pen 1. When is approached, the position detection circuit 3 detects the XY coordinates from the propagation time up to that location by utilizing the fact that the magnetostrictive vibration increases at that location by the bar magnet provided on this location. Further, in the latter, each magnetic body arranged orthogonally is excited by an alternating current, and the induced voltage is taken out by each detection coil,
The XY coordinates are detected by utilizing the fact that when the same input pen approaches, the magnetic permeability of the magnetic material locally changes and the induced voltage changes.

The antenna coil 23 is configured by disposing a conductive wire coated with an insulating coating such as vinyl chloride around the coordinate input range of the tablet body 22, here, on the back surface of the top panel 21a of the casing 21 around the frame 24. It is a thing. It should be noted that the illustrated example has one turn, but it may have a plurality of turns if necessary.

FIG. 3 shows a detailed configuration of the timing control circuit 4, in which 401 is an oscillator (OSC), 402 is a frequency dividing counter, and 4
03, 404 is a NAND gate, 405 is a transmission terminal, 406 is a reception terminal, 407, 408 is a reception switch, 409, 410, 411 is an amplifier, 412 is a filter, 413 is a phase detector (PSD), 414 is a low pass filter (LPF), 415a, 415b are Comparator, 416a, 4
16b is an output terminal.

FIG. 4 is a signal waveform diagram in each part of FIG. The operation will be described in detail below.

A clock pulse of, for example, 910 kHz generated from the oscillator 401 is divided into 1/2 and 1/32 by the frequency division counter 402. One of the input terminals of NAND gate 403 is divided by 45
The pulse signal A of 5kHz is input, and the other input terminal is 1 /
28.44kHz pulse signal divided into 32 (pulse width 17.6μ
s) is input, and the output is further sent to the NAND gate 404, and becomes a signal B which outputs or does not output a pulse signal of 455 kHz every 17.6 μs as shown in FIG.

The signal B is transmitted to the antenna coil 23 via the transmission terminal 405 and further transmitted as a radio wave. At this time, for example, in the tuning circuit 12a of the input pen 1, if the switch 121a is on, the tuning circuit 12a resonates with the transmitted electric wave. Since the circuit continues to resonate while being attenuated even when the transmission on the transmitting side is stopped, a signal C as shown in FIG. 4 is generated, and the signal C is transmitted from the coil 122 as a radio wave and the antenna Received by the coil 23.

Since the reception changeover switches 407 and 408 are switched every 17.6 μs by the 28.44 kHz pulse signal, the signal from the reception terminal 406 is taken in only during the transmission stop period. If the switch 121a of the tuning circuit 12a is on, the received signal is
It becomes the signal D shown in FIG. 4, and becomes the signal D'when it is off. The received signal D is amplified by the amplifiers 409 and 410 to become the signal E, the noise component is removed through the mechanical filter 412 having the resonance frequency of 455 kHz, and the signal E is sent to the phase detector 413 via the amplifier 411. The amplifier 410 has an automatic level control function to make the signal E have a constant amplitude.

The 455 kHz pulse signal A is input to the phase detector 413, and at this time, the phase of the received signal E is made to match the phase of the pulse signal A. Therefore, as shown in FIG. A signal F obtained by returning E is output.

The signal F is converted into a flat signal by the low-pass filter 414 having a sufficiently low cutoff frequency and input to one of the input terminals of the comparators 415a and 415b. A predetermined threshold voltage + VT is previously input to the other input terminal of the comparator 415a, the output of the low-pass filter 414 is compared with the threshold voltage + VT, and a high (H) level signal Ga is output to the output terminal 416a. Is output.

In the case of the signal D ′, both the signals E and F are “0” level, and the signal Ga is also low (L) level (not shown). Therefore, the operating state of the switch 121a is identified.

When the signal Ga is at a high level, it is in a pen-down state,
When it is defined that the pen is not in the pen-down state when it is at the low level, and the signal Ga is sent to the position detection circuit 3, the input pen 1 is operated on the tablet 2 and the input pen 1 is moved to the position where the coordinate input is desired. The position can be input only by pressing the tip on the tablet 2.

Next, in describing the case where the switch 121b is operated, the operation waveform of the phase detector 413 will be described including the case where only the switch 121a is operated.

Assuming that the input signal of the phase detector 413 is a signal obtained by dividing the frequency by the frequency dividing counter 402 by eR, refer to FIG. 5A. Since this is a square wave with an amplitude of 1, its angular velocity is ωR. Then, by Fourier expansion, eR = (4 / π) {sinωRt ＋ (1/3) sin3ωRt ＋ (1/5) gi
n5ω t + ...} (1) If the signal from the amplifier 411 side is ei, which is composed of the synchronous component eS of the maximum value ES and the angular velocity ωS and the asynchronous component eN that is the noise of the maximum value EN and the angular velocity ωN, the angular velocity ωS = ωR. .

ei ＝ eS ＋ eN ＝ ES sin ωR t ＋ EN sin ωN t (2)

Now, if only switch 121a is on, signals eR and eS
Is in phase, and if the output of the phase detector 413 is e0, then e0 = eR × ei = (4 / π) {ES sin ωR t} {sin ωR t +
(1/3) sin3 ωR t ＋ ……} + (4 / π) {EN sin ωN
t} {sin ωRt ＋ (1/3) sin3ωRt ＋ ……} ＝ (4 /
π) ES {sin ² ωR t ＋ (1/3) sin ωR t ・ sin ωR t
＋ ……} ＋ (4 / π) EN {sin ωN t ・ sin ωR t ＋ (1/3)
sin ωN t · sin3 ωR t + ……} ………… (3). Here, since only the sin ² ωR t in the first term of the equation (3) contains a DC component and the others are AC components, pay attention to only the DC component as the output of the low-pass filter 414 in the next stage. , And let this be the DC output ▲ ▼, sin ² ωR t ＝
From 1/2) {1-co72 ωR}, ▲ ▼ = (2 / π) ES ………… (4). Expression (4) is the average value of the signal eO in FIG. 5 (A).

Next, when the switches 121a and 121b are turned on, the signals eR and e
If the phase difference from S is φ, then φ = 180 °, and if the first term in equation (3) is e′O, then e′O = (4 / π) ES {sin (ωR t −φ) sin ωR t} =
(4 / π) ES (1/2) {cos φ-cos (2ωR t + φ)}…
...... (5) and the second term of the equation (5) is the AC component, so the DC output ▲ ▼ becomes ▲ ▼ = (2 / π) ES cos φ …… (6), and from φ = 180 ° , ▲ ▼ =-(2 / π) Es. The equation (6) is the average value of the signal e0 in FIG. 5 (c), and the signal ▲ ▼ is input to the comparators 415a and 415b. The comparator 415b is compared with a predetermined threshold voltage −VT, and a low (L) level signal Gb is output to the output terminal 416b.
Is output.

When the switch 121b is off, the signal e0 is the threshold voltage −VT
Is always higher and its output signal Gb is always high (H)
It becomes a level (not shown).

FIG. 6 shows an input pen which replaces the input pen 1 of FIG. 1 with four sets of tuning circuits RE1 to RE4 and four switches SW1 to SW4 for selectively turning them on, respectively. In addition to the above configuration, a transfer device (SHIFT) 417 for advancing the signal eR by the 1/2 division of the frequency division counter 402 by 90 ° is added, and further, the transfer device 417
Phase detector 413 ′ that receives the signal of
And the low-pass filter 41 that extracts the DC component from the output
4'is added to extract the operation signals of the switches SW1 to SW4 from the four comparators 415a to 415d.

Each of the tuning circuits RE1 to RE4 is, for example, a portion of the cap 16 of the input pen 1 which is of a rotary type so as to correspond to each color designation, the fill designation and the erase designation.

The operation of the circuit of FIG. 6 will be described below, focusing on the parts different from those of FIG.

The signals eS from the tuning circuits RE1 to RE4 are referred to FIG. 5 again, and as shown in (A), (B), (C) and (D), the signals eS are respectively 0 °, 90 °, 180 ° and 270 with respect to the signal e0. It has a phase difference of °. Then, for the phase difference between 90 ° and 270 °, for example, φ = 90 ° or φ = 270 ° in equation (6), and e0 = 0
Becomes Therefore, in order to detect the signal e0 at φ = 90 ° and φ = 270 °, the phase shifter 417 advances the signal eR by 90 ° as shown in FIG. As a result,
cosφ is replaced by sinφ, the low pass filter in this case
The output of 414 'is φ = 90 °, and the signal e of FIG.
The average value of 0 is ▲ ▼ ＝ (2 / π) ES, and φ ＝ 270
7 °, the average value of the signal e0 in FIG. 7 (D) ▲ ▼ =
− (2 / π) ES, and the output signals Gc and Gd are similarly obtained by the comparators 415c and 415d.

Although the difference in the frequency of the reflected radio waves is detected as a change in the phase in the above embodiment, it goes without saying that it can be detected as it is as a difference in the frequency. Further, the coordinate input device described with reference to FIG. 2 is an example, and the magnetic generator in the input pen 1 is also provided corresponding to this, so that it is particularly necessary in a device used for another coordinate input device. is not. Further, it is obvious to those skilled in the art that the position indicator having a plurality of switches according to the present invention is generally suitable as a cursor.

(Effect of the invention) As described above, according to the present invention, the frequency of the radio wave transmitted from the tablet of the coordinate input device is configured by forming the tuning circuit having different tuning frequencies according to the operation of each of the plurality of switches. To reflect to the coordinate input device which one of the plurality of switches is being operated, for example, to specify color or erase, and also to other circuits of the coordinate input device. There is no need for a cord between the cord and the cord, so that the cord does not interfere with the movement of the cord as in the past, or does not break due to fatigue. As described above, the transmitter including the oscillator circuit and the battery that powers the transmitter make the position indicator heavy and / or charge or replace the battery. There is an advantage that the operability and the maintainability are very good, such as not having to be troublesome.

[Brief description of drawings]

FIG. 1 is a sectional view showing one embodiment of the position indicator of the present invention,
FIG. 2 is a perspective view showing an example of a coordinate input device using the position indicator of the present invention, FIG. 3 is a block diagram of a timing control circuit in the case of two switches, and FIG. Waveform diagram, FIG. 5 is a waveform diagram for explaining the operation of the phase detector of FIG. 3, FIG. 6 is a block diagram of the timing control circuit when there are four switches, and FIG. 7 is the phase detection of FIG. It is a waveform diagram explaining the operation of the container. 1 ... Input pen (position indicator), 12a, 12b, RE1, RE2, RE3, RE
4 ... Tuning circuit, 121a, 121b, SW1, SW2, SW3, SW4 ... Switch,
122 ... coil, 123a, 123b ... condenser, 124a, 124b ... variable condenser.

Claims (1)

[Claims] 1. A position indicator used in a coordinate input device, for indicating to a tablet the position to be measured, and transmitting the state of which switch of a plurality of switches is being operated. , A tuning circuit that is tuned to a radio wave transmitted from the tablet and has a plurality of different tuning frequencies configured by operating a plurality of switches, and changes in the tuning frequency based on the operation of each of the plurality of switches, A position pointing device in a coordinate input device, wherein transmission is performed by radio waves reflected from the plurality of tuning circuits having different tuning frequencies to the tablet.