JPS6349921A - State detecting system for position indicator - Google Patents

Abstract

PURPOSE:To improve the operability of a position indicator by providing the position indicator with plural tuning circuits and their switches and intermittently originating radio waves having frequency equivalent to tuning frequency from an antenna coil mounted on a tablet. CONSTITUTION:A coordinate input device is constituted of a tablet 1, a position indicator (input pen) 2, a position detecting circuit 3, and a timing control circuit 4. The tablet 1 forming the coordinate input part is constituted by storing a tablet body 12 and an antenna coil 13 in a non-magnetic metal case body 11, connecting the position detecting circuit 3 to the tablet body 12 and connecting the timing control circuit 4 to the antenna coil 13. The input pen 2 includes a position specifying magnetism generator (rod magnet) 21 and two tuning circuits 22a, 22b having capacitors and coils respectively. When the switches of respective tuning circuits 22a, 22b are ON, the circuits 22a, 22b originate phase differences respectively inherent in an originating signal from the antenna coil 13 and these states are detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for detecting the state of a position indicator in a coordinate input device.

(Prior Art) Conventionally, in a coordinate input device, a position indicator (g) that specifies only the coordinate position to be input on a tablet (hereinafter referred to as
This is called the pen-down state. ) is to provide a switch means on the position indicator, and only when the pen is down,
The device is configured to turn on (or turn off) the switch means and send a timing signal based on the on (or off) of the switch means to the IQ device detection circuit via a code or using ultrasonic waves or infrared rays. there were.

(Problems to be Solved by the Invention) However, in the case where a timing signal is sent from a position indicator using a code, the code impairs the operability of the position indicator. In the case of a device that transmits signals, the transmitter, signal generation circuit, battery, etc. must be installed in the position indicator itself, making the configuration complicated, large, and requiring a lot of human labor. There was a problem with making it worse.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method that can detect the positional state of a position indicator, the state of each operation designation, etc., without reducing the operability of the position indicator.

In order to solve the above problems, the present invention includes a tablet constituting a coordinate input section, a position indicator such as a stylus pen, and a method for driving the tablet and inputting coordinates using the position indicator. In a coordinate input device equipped with a position detection circuit for detecting a position, each of which forms a pair including a coil and a capacitor, and responds to an external signal with the same tuning frequency and different phase. The position indicator is equipped with a plurality of tuned circuits that emit radio waves and a switch that turns on and off the connection between the coil and capacitor of each tuned circuit, and antenna coils are installed around the coordinate input range of the tablet. an alternating current signal having a frequency equivalent to the same 'A frequency is intermittently applied to the antenna coil to transmit radio waves, and when the transmission of the radio waves is stopped, a signal responded by the tuning circuit is transmitted to the antenna coil. detect the position and operation state of the position indicator, and identify the on/off state of the switch for each tuned circuit based on the received signals having different phases with respect to the signal transmitted from the antenna coil. That's how I did it.

According to the present invention, each tuned circuit, when its respective switch is turned on, transmits signals with a unique phase difference with respect to the transmitted signal of the antenna coil.

An antenna coil receives this. By this reception, the position operation state of the position indicator is detected. Then, it is determined which switch of the position pointing device is turned on based on the received signals having mutually different phases.

(Embodiment) FIG. 1 shows an embodiment of the present invention, in which 1 is a tablet and 2 is a position indicator (hereinafter referred to as an input pen).
, 3 is a position detection circuit, and 4 is a timing control circuit.

The tablet 1 has a tablet main body 12 and an antenna coil 13 housed in a non-magnetic metal casing 11. The tablet main body 12 is connected to a position detection circuit 3, and the antenna coil 13 is connected to a timing control circuit 4. It is connected.

The tablet main body 12 is driven by the position detection circuit 3,
The tablet main body 12 constitutes a detection section that detects the position designated by the input bezel 2, and the tablet main body 12 is arranged at the center of the housing 11. Note that a frame 14 drawn on the top panel 11a of the housing 11 indicates the coordinate input range.

The tablet main body 12 and position detection circuit 3 include:
For example, patent application No. 58-2385 filed by the present applicant.
No. 32 “Coordinate position detection device” (Japanese Patent Application Laid-Open No. 60-1296
16) or the position detection device (see Japanese Patent Application Laid-open No. 60-176134) described in Japanese Patent Application No. 59-33083. In the former case, the tablet main body 1
A large number of magnetostrictive transmission media are arranged parallel to the surface of the input ben 2 and perpendicular to each other, and magnetostrictive vibrations are periodically propagated from one end to the other end of each medium, and when the input ben 2 approaches, this Utilizing the fact that the magnetostrictive vibration increases at that location due to the bar magnet provided at the location, the position detection circuit 3 detects the XY coordinates from the propagation time to that location. Also, among the winners,
Each orthogonally arranged magnetic body is excited with alternating current and its induced voltage is extracted by each detection coil, and when a similar input pen approaches, the magnetic permeability of the magnetic body changes locally and the induced voltage changes. This is used to detect the XY coordinates.

The antenna coil 13 connects a conductor coated with an insulating coating such as vinyl chloride to the area around the coordinate input range of the tablet body 12.
Here, the upper panel 11 of the casing 11 around the frame 14
It is arranged on the back side of a. In the illustrated example, the turn is one turn, but it may be a plurality of turns if necessary.

The input bench 2 includes a magnetic generator for specifying the position, such as a bar magnet 21, and two sets of tuned circuits 2 including a coil and a capacitor.
2a and 22b are built-in.

FIG. 2 shows the detailed structure of the input pen 2, in which a core body 24 of a ballpoint pen or the like is placed inside a pen shaft 23 made of a non-gold rtA material such as synthetic resin, and the core body 24 is slidably inserted into the pen shaft 23. A bar magnet 21 with a through hole capable of accommodating the magnet, a coil spring 25,
Switches 221a, 221b 1 Coil with iron core 222
, two capacitors 223a, 223b shown in FIG.
and two variable capacitors 224a, 22 for fine adjustment.
4b, two sets of tuning circuits 22a and 22b are integrally combined and built in, and a cap 26 is provided at the rear end.
is installed.

The switch 221a is turned on when the core body 24 is pushed into the pen shaft 23 by, for example, pressing its tip against the tablet surface, and the rear end presses the switch 221a via the coil spring 25 to turn it on. and switch 22
1b is designed so that when the switch 221b is turned on, a signal is separately sent to the host computer each time the switch 221b is turned on by a push operation, and depending on the number of times the switch 221b is turned on, for example, changing the color or filling in a certain part is specified. There is. Also,
As shown in FIG. 3, the capacitor 223a and the variable capacitor 224a are connected in parallel with each other, and one end of the coil 222 is connected to one end of these via a switch 221a. The other end is connected to constitute one parallel common circuit 22a. And capacitor 223b, variable capacitor 22
4b, co, il 222. Switch 221b is similarly connected so that in this case another parallel resonant circuit 22b is configured when switches 221a, 221b are both turned on.

Note that the resonant circuit 22a is adjusted and set to be in phase with the radio waves transmitted from the antenna coil 13 and resonate (tuned) to the frequency thereof, and the resonant circuit 22b is adjusted and set so as to resonate with a phase difference of 180° between them. Ru. Resonant circuit 22
By the settings of a and 22b, the selectivity Q-R/(ωO
Li, where R is the resistance value of the resonant circuit, [is the inductance]
changes, causing a phase shift. At the same time, the resonant frequency also changes, making resonance possible.

FIG. 3 shows the detailed configuration of the timing control circuit 4. In the figure, 401 is an oscillator (OSC), 402 is a frequency division counter, 403 and 404 are Nant gates, 405 is a transmission terminal, 406 is a reception terminal, 407, 408 are reception selector switches, 409, 410, 411 are amplifiers, 412 are filters, 413 are phase detectors (PSD), 414 are low pass filters (LPF), 415a, 415b are comparators, 416a, 416b are output terminals It is.

FIG. 4 is a signal waveform diagram at each part of FIG. 3. The operation will be explained in detail below.

For example, a clock pulse of Ilz at 910 generated by the oscillator 401 is divided into 1/2 and 1 by the frequency division counter 402.
The frequency is divided by /32. One input terminal of the Nant gate 403 receives a pulse signal A of 455 and 112 divided by 1/2, and the other input terminal receives a pulse signal A of 28.44 and H2 divided by 1/32. Pulse signal (pulse width 17.
6JJs) is input, and its output is roughly sent to the Nantes gate 404, and as shown in FIG.
A signal B is generated which outputs or does not output a H2 pulse signal every 455 seconds.

The signal B is sent to the antenna coil 1 via the transmission terminal 405.
3, and is further transmitted as radio waves. At this time,
For example, in the tuning circuit 22a of the input vent 2, when the switch 221a is on, the tuning circuit 22a resonates with the transmitted radio waves. Since the circuit continues to resonate while being attenuated even when the transmission on the transmitting side stops, it generates a signal C as shown in FIG.
The signal is transmitted as a radio wave and received by the antenna coil 13.

Since the reception selector switches 407 and 408 are switched every 17.6 ils by the above-mentioned 28.44 and 112 pulse signals, the reception terminal 406 is switched only during the transmission stop period.
Incorporate No. 13. The received signal is transmitted through the tuning circuit 22a.
If the switch 221a is on, the signal will be as shown in FIG. 4, and if it is off, the signal will be D'. The received signal is sent to amplifier 409. /110 and becomes the signal E, which is further passed through a mechanical filter 412 with a resonance frequency of 455KIIz to remove noise components, and then sent to the amplifier 41.
1 to the phase detector 413. Note that the amplifier 410 has an auto level control function, and keeps the signal E at a constant amplitude.

The pulse signal of the 455KIIZ 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, so that the received signal is exactly as shown in FIG. A signal F is output by folding back the signal E.

The signal @F is a low-pass filter with a sufficiently low cutoff frequency 41
4, the signal is converted into a flat signal, and the comparator 415a,
415b is input to each one input terminal. The other input terminal of the comparator 415a is input with a predetermined one-torture value voltage +VT in advance, and the low-pass filter 414
The output of is compared with the threshold voltage +VT, and the output terminal 416a is
A high (H) level signal Ga is output.

In the case of signal D', both signals E and F are at "O" level, and signal Ga is also at low level (not shown). Therefore, the operating state of switch 221a is identified.

If the signal Ga is defined as being in a pen-down state when it is at a high level and not being in a pen-down state when it is at a low level, then the signal Ga is sent to the position detection circuit 3.
A position can be input simply by operating the input ben 2 on the tablet 1 and pressing the tip of the input ben 2 onto the tablet 1 at the position where the coordinates are desired to be input.

Next, in explaining the case where the switch 221b is operated, the rotation waveform of the phase detector 413 will be explained, including the case where only the previous switch 221a is operated.

Assuming that No. 43 obtained by dividing the frequency of the frequency division counter 402 by 1/2 is eR as the input of the phase detector 413, Fig. 5(A)
Referring to
r) (sin ωRt+(1/3) sin3ωRt+(
115) sin5ωlt t +・) −・−
・-(1). Assuming that the signal from the amplifier 411 side is ei, which consists of a synchronous component eS with a maximum value ES and an angular velocity ωS, and an asynchronous component eN which is a noise with a maximum value EN and an angular velocity ωN, the angular velocity is ωS - ωR. From, ei = eS + eN = ES sin
ωRt+EN sin ωN t −−−−−・(2
).

Here, if only the switch 221a is on, the signal e
R and es are in phase, and the output of the phase detector 413 is
o, then eO=eRxei = (4/1(ES sin ωR
t) (sinωRt + (1/3) sin3 ωRt
+-・・-・)+(4/1(EN sin oaN t
Hsin (IJRt+(1/3)sin3ωRt
+−・−−− Tsukasa=(4/π) ES (sin2ω
Rt + (1/3) sin ωRt −5in3ωRt
+・−・・・・）+(4#r) EN (sinωN
t −sin ωRt+(1/3)sin (1)N
t −5in3ωRt +・・・−)・・・・・・・・・
・(3) becomes. Here, Sln ωRt of the first term of equation (3)
Since only the DC component contains a DC component and the others are AC components, if we focus on only the DC component as the output of the next-stage low-pass filter 414 and take this as the DC output eO, then 5in2ωR
From t = (1/2H1-cos2 ωRt), e
O==(2/π) ES ・−・・−A4). Equation (4) is the average value of the signal eO in FIG. 5(A).

Next, when the switches -221a and 221b are turned on, the phase difference between the signals eR and es is set to φ, and φ...180
°, and if the first term of equation (3) is e' 0, then e' O=(4/yr) ES (sin(ωRt:
−φ) sin CL) Rt ) = (4/7T)
ES (1/2)(CO3φ−CO3(2ωlet
÷φ)) ・・・・・・・・・(5), (5)
Since the second term in the equation is an AC component, the DC output eO is eO-(2/π) ES cosφ...
(6), and from φ-180°, it becomes eo--(2/π)ES. Equation (6) is the average value of the signal eO in FIG. 5(C), and the signal eO is the comparator 415a.

415b. Comparator 415b is compared with a predetermined 8iiiIII voltage -VT and output terminal 416b
A low (L) level signal Gb is output.

Note that when the switch 221b is off, the signal eO is always higher than the threshold voltage -VT, and its output signal Go is always at a high (11) level (not shown).

FIG. 6 shows an input pen that replaces the input pen 2 in FIG.
In the configuration shown in the figure, a transfer device (SIIIFT) advances the signal eft by 172 frequency division of the frequency dividing counter 402 by 90
) 417 is added, and furthermore, a phase detector 413' that receives the signal of the transferer 417 and the signal of the amplifier 411, and a low-pass filter 414 that removes the DC component from its output.
′ and four comparators 415a to 41
5d, each operation signal of the switches SW1 to SW4 is taken out.

Each of the tuning circuits RE1 to RE4 makes the cap 26 of the input pen 2 rotatable, for example, to correspond to each color designation, the filling designation, and the erasing designation.

Regarding the circuit shown in Figure 6 below, ? The operation will be explained, focusing on the parts that are different from the A3 diagram.

Referring again to FIG. 5, the signals O5 from each tuning circuit RE1 to RE4 are at 0°, 90', and 180° with respect to the signal CO, respectively, as shown in (A), (B), (C), and (D).
”.

It has a phase difference of 270°. And analogy 90' and 2
For a phase difference of 70°, eo = o by setting φ-90° or φ-270° in equation (6). Therefore, φ
To detect the signal eo at =90'', φ=270', the signal eR is advanced by 90° by phase shifter 417 as shown in FIG.

As a result, COSφ in equation (6) is replaced by sinφ, and the output of the low-pass filter 414' in this case is φ-90.
', Fig. 7 (8) Average value of signal eO = (
2/;l ES, and at φ-270, the average value of the signal in FIG.

(Effects of the Invention) As explained above, according to the present invention, not only is there no need for a cord between the position indicator and other circuits, but only a tuning circuit including a coil and an densifier is required. ,
There is no longer a need for complex signal generation circuits, batteries, etc., as in the past, and the operating status of multiple switches provided on the position indicator can be similarly identified without codes, so each switch can be used to identify, for example, the color of the input pen. It is possible to provide a position indicator that is extremely easy to operate while also making it possible to specify and erase specifications.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a position indicator showing an embodiment of the present invention, Fig. 2 is a sectional view of an input pen, Fig. 3 is a block diagram of a timing control circuit when there are two switches, and Fig. 4 is a Figure 3 is a waveform diagram of each part, Figure 5 is a waveform diagram explaining the operation of the phase detector in Figure 3, Figure 6 is a block diagram of the timing control circuit when there are four switches, and Figure 7 is a waveform diagram explaining the operation of the phase detector in Figure 3. 7 is a waveform diagram illustrating the operation of the phase detector of FIG. 6. FIG. 1...Tablet, 2...Input pen (position indicator)
, 3... Position detection circuit, 4... Timing control circuit, 13... Antenna coil, 14... Coordinate input range, 22a, 22b, REI, RE2, RE3. RE 4 =...tuned circuit, 221a, 221b,
SW 1.8 W 2゜SW3. SW4...Switch, 415a, 415b, 415c, 415d...Comparator.

Claims (1)

[Scope of Claims] A coordinate input device comprising a tablet constituting a coordinate input section, a position indicator such as a stylus pen, and a position detection circuit that drives the tablet and detects a coordinate input position by the position indicator. , a plurality of tuned circuits each including a coil and a capacitor, and each of which transmits radio waves in response to an external signal at the same tuning frequency and with a different phase; and each of the tuning circuits. A switch is provided on the position indicator to turn on and off the connection between the coil and the capacitor that formed the pair, an antenna coil is provided around the coordinate input range of the tablet, and an AC signal of a frequency equivalent to the tuned frequency is transmitted to the position indicator. causing the antenna coil to intermittently transmit radio waves, and when the transmission of the radio waves is stopped, causing the antenna coil to receive a signal to which the tuning circuit responds, thereby detecting the position operation state of the position indicator; A state detection method for a position indicator, characterized in that the on/off state of the switch for each of the tuning circuits is identified based on the received signals having different phases with respect to the transmitted signal of the antenna coil.