JPH02130620A - Coordinate input device - Google Patents

Abstract

PURPOSE:To execute correction with irreducible minimum operation by judging whether it is necessary to correct an oscillation arriving time by the reacting fluctuation of respective circuit elements to be related to the detection of oscillation arrival or not based on detected temperature information and alarming the correction. CONSTITUTION:A user has an oscillating pen 3 in a hand and inputs coordinates in a position on an oscillation transmitting board 8. The oscillation transmitting board 8 transmits ultrasonic oscillation, which is received from the oscillating pen 3, to oscillation sensors 6a-6c. Signals to be detected by the sensors 6a-6c are respectively given to a signal waveform detecting circuit 9 and from an oscillation transmitting time to the sensor to be obtained by the detecting circuit 9, the position of the oscillating pen 3 is detected in an arithmetic and control circuit 1. At such a time, the arithmetic and control circuit 1 judges whether it is necessary to correct the reacting fluctuation arriving time of the respective circuit elements to be related to the detection of the oscillation arrival or not based on the temperature information to be detected by a temperature sensor 12. Then, when it is judged that the correction is needed, such a condition is alarmed by a buzzer 13 and the prescribed operation of the coordinate input to be related to correction processing is requested.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention detects vibrations input from a coordinate input device, particularly a vibrating pen, using a plurality of vibration sensors provided on a vibration transmission plate, and transmits vibrations to each vibration sensor. The present invention relates to a coordinate input device that detects the position of the vibrating pen from vibration transmission time.

[Conventional technology] A brief explanation of this method is as follows.

An input pen is brought into contact with a vibration transmission plate (forming the coordinate input surface of the tablet), and vibrations generated from the input pen are detected by a plurality of vibration sensors provided at predetermined positions on the vibration transmission plate. Then, by measuring the vibration transmission time to each vibration sensor, the designated coordinate position is calculated.

The advantage of this method is that the vibration transmission plate that makes up the input tablet has a very simple structure and can be manufactured at low cost.Also, transparent glass etc. can be used as the vibration transmission plate, so the display screen can be For example, it can be placed on the front or used over a document or the like.

However, on the other hand, accurate coordinate position detection may not be possible unless the influence of the phase velocity of vibration transmission on the vibration transmission plate and the influence of circuit delay time of the detection circuit are corrected in coordinate position detection by vibration detection. It is a fact. still,
This circuit delay time includes not only the electrical circuit but also the inherent delay time of the circuit through which mechanical vibration is transmitted between the vibration bend and the vibration transmission plate.

[Problems to be Solved by the Invention] Figure 8 shows time t on the horizontal axis and vibration transmission distance from the human force point to the vibration sensor on the vertical axis, and the group delay time tg during which the envelope of the vibration waveform travels a certain distance. , which shows changes in the phase delay time tp during which the phase of the waveform progresses.

As shown in the figure, the circuit delay time at is always included even at the distance "0", and the curves (straight lines) of each delay time are offset to the right of the graph.Furthermore, the phase wavelength is changed according to the wavelength as shown in the figure. , a regular phase delay occurs, but the distance “O”
The difference tof between the group delay time tg and the phase delay time, that is, the phase offset changes depending on the circuit delay time.

In the method of measuring the vibration transmission time by detecting the transverse wave component on the vibration transmission plate, a method is known in which the vibration transmission time is determined using both the group delay time tg and the phase delay time tp. In these methods, correct vibration transmission time cannot be obtained unless the circuit delay time et and phase offset tof are corrected.

For this reason, in the past, a correction value corresponding to the average circuit delay time et and phase offset tof measured in advance was stored, and the vibration transmission time was corrected by subtracting this from the measured value.

However, this circuit delay time at and phase offset to
To determine f, it is necessary to perform calculations on data sampled at a certain point using constants such as group velocity, phase velocity, and period. Calculation errors may lead to a decrease in accuracy in determining coordinates.

Furthermore, since the actual circuit delay time changes depending on environmental changes such as temperature, the conventional method has a problem in that it is not possible to accurately measure vibration propagation time regardless of changes in environmental conditions. Furthermore, even if the user were to make this correction, it would be impossible to grasp every change in environmental conditions and make the correction each time.

The present invention has been made in view of such problems, and is a coordinate input device that easily corrects the vibration arrival time due to reaction fluctuations of each circuit element related to temperature-dependent vibration arrival detection, and moreover, with the minimum necessary operations. This is what we are trying to provide.

[Means for Solving the Problem] In order to solve this problem, the present invention includes the configuration shown below.

That is, temperature is detected in a coordinate human-powered device that detects vibrations input from a vibrating pen using a plurality of vibration sensors provided on a vibration transmission plate, and detects the position of the vibrating pen from the vibration transmission time to each vibration sensor. a temperature detection means; a determination means for determining whether or not correction due to reaction fluctuations of each circuit element related to detection of vibration transmission time is required based on temperature information detected by the temperature detection means; and notification means for notifying a request for a predetermined coordinate input operation related to correction processing when the means determines that correction is necessary.

[Function] In the configuration of the present invention, when the determining means determines that correction is necessary based on the temperature detected by the temperature detecting means, the notifying means issues a request for a coordinate input operation related to the correction. This is to inform the public.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Description of device configuration (FIG. 1)> FIG. 1 shows the structure of the coordinate input device in this embodiment.

In the figure, 1 is an arithmetic control circuit that controls the entire device and calculates coordinate positions. Reference numeral 2 denotes a vibrator drive circuit, which vibrates the pen tip within the vibrating pen 3. Reference numeral 8 denotes a vibration transmission plate made of a transparent member such as an acrylic or glass plate, and coordinates using the vibrating pen 3 are manually controlled by touching the vibration transmission plate 8. And this vibration transmission plate 8
An antireflection material 7 is provided on the outer periphery of the material 7 to prevent (reduce) reflected vibrations from returning to the center, and vibration sensors 6a to 6a, such as piezoelectric elements, that convert mechanical vibrations into electrical signals are provided at the boundaries thereof. 6C is fixed at the position shown. Although the details will be described later, there is a mark 8a at a predetermined position on the vibration transmission plate 8.
is provided.

Reference numeral 9 denotes a signal waveform detection circuit that outputs a signal indicating that vibration has been detected by each of the vibration sensors 6a to 6c to the arithmetic control circuit 1.

Reference numeral 11 denotes a display capable of displaying dots, such as a CRT (or liquid crystal display), which is disposed behind the vibration transmission plate 8. Then, by driving the display drive circuit 10, a dot is displayed at the position traced by the vibration bevel 3, which can be seen through the vibration transmission plate 8 (as it is made of a transparent member). That is, a dot is displayed at a position on the display 11 corresponding to the detected coordinates of the vibrating pen 3, and an image composed of elements such as points and lines input by the vibrating pen 3 is displayed as if it were written on paper. appears after the trajectory of the vibrating pen.

In addition, according to such a configuration, the menu can be displayed on the display 11, and a manual method such as having the vibrator 3 select the item or displaying a prompt and touching the vibrator 3 to a predetermined position can be performed. It can also be used.

12 is a temperature sensor, and the detected temperature is taken into the arithmetic control circuit 1. Also, 1
3 is a buzzer, and according to instructions from the arithmetic control circuit 1,
It generates a warning sound outside. Note that the uses of the temperature sensor 12 and the buzzer 13 will be described later.

FIG. 2 shows the structure (cross-sectional view) of the vibrating vent 3 according to the embodiment.

A vibrator 4 built into the vibrator 3 is connected to a vibrator drive circuit 2.
Driven by. A drive signal for the vibrator 4 is supplied as a low-level pulse signal from the arithmetic control circuit 1, and is applied to the vibrator 4 after being amplified by a predetermined gain by a vibrator drive circuit 2 capable of low impedance driving.

The electrical drive signal is converted into mechanical ultrasonic vibration by the vibrator 4 and transmitted to the vibration transmission plate 8 via the horn portion (pen tip) 5.

Here, the vibration frequency of the vibrator 4 is selected to a value that can generate plate waves on the vibration transmission plate 8 made of acrylic, glass, or the like. Further, when driving the vibrator, a vibration mode is selected in which the vibrator 4 mainly vibrates in the vertical direction in FIG. 2 with respect to the vibration transmission plate 8. Further, by setting the vibration frequency of the vibrator 4 to the resonance frequency of the vibrator 4, efficient vibration conversion is possible.

The elastic waves transmitted to the vibration transmission plate 8 as described above are plate waves, and compared to surface waves, scratches on the surface of the vibration transmission plate, etc.
It has the advantage of being less affected by obstacles.

Explanation of the arithmetic control circuit (Fig. 3)> In the above-described configuration, the arithmetic control circuit 1 operates at a predetermined period (Figure 3).
For example, every SMS), a signal for driving the vibrator 4 in the vibrating vent 3 is output to the vibrator drive circuit 2, and an internal timer (consisting of a counter) starts measuring time. The vibrations generated by the vibration vent 3 arrive with a delay depending on the distance to the vibration sensors 6a to 6C. The vibration waveform detection circuit 9 detects signals from each of the vibration sensors 6a to 6c, and generates a signal indicating the timing of vibration arrival at each vibration sensor through waveform detection processing, which will be described later. Detecting the arrival time of vibration to each vibration sensor 6a to 6C by manually inputting this signal,
Then, the coordinate position of the vibrating ben is calculated.

Then, the arithmetic control circuit 1 drives the display drive circuit 10 based on the calculated coordinate position information of the vibrating ben 3 to control the display operation of the display 11.

FIG. 3 shows the internal configuration of the arithmetic control circuit 1 in the embodiment, and each component and its operation outline will be explained below.

In the figure, numeral 31 is a microcomputer that controls the arithmetic control circuit 1 and the entire Honjo Hitoshika device, and includes internal counters,
A ROM 31a that stores operating procedures and the regular coordinate position of the mark 8a on the progress transmitting plate 8, and a RAM that is used as a work area and stores correction values, etc., which will be described later.
It has a built-in 31b. 33 is a timer (consisting of a counter) that measures a reference clock (not shown), and outputs a start signal to the vibrator drive circuit 2 to start driving the vibrator 4 in the vibrating vent 3. in,
Start counting the time. In other words, this synchronizes the start of time measurement and the timing of vibration generation.

The circuits that form the place name components will be explained step by step.

Each vibration sensor 6a obtained via the signal waveform detection circuit 9
The timing signal of the arrival of the vibration of ~6C is manually input to the latch circuits 348 to 34c via the detection signal input port 35. The latch circuits 34a to 34c are the vibration sensors 6a to 6C.
, and when each receives a timing signal that is a signal from a corresponding vibration sensor, the timer 3 at that time
Latch the time value of 3. When the determination circuit 36 determines that all detection signals have been received, it outputs a signal to that effect to the microcomputer 31. When the microcomputer 31 receives this signal from the determination circuit 36, it reads the vibration arrival time from the latch circuits 34a to 34c to each vibration sensor, performs a predetermined calculation, and calculates the coordinates of the vibration ben 3 on the vibration transmission plate 8. Calculate the position.

Then, by outputting the calculated coordinate position information to the display drive circuit 10 via the 10 boat 37,
For example, a dot or the like is displayed at a corresponding position on the display. Although the explanation is complicated, the temperature sensor 12 is composed of, for example, a thermistor, and its resistance value is taken into the microcomputer 31 via the I10 port 37. Further, the buzzer 13 is similarly driven via the I10 boat 37.

Explanation of vibration propagation time detection (Figures 4 and 5)> Below,
The principle of measuring the vibration arrival time to the vibration sensor will be explained.

FIG. 4 shows the detected waveform input to the signal waveform detection circuit 9,
FIG. 3 is a diagram for explaining a vibration transmission time measurement process based on this. Note that although the vibration sensor 6a will be explained below, the same applies to the other vibration sensors 8b and 6c.

It has already been explained that the measurement of the vibration transmission time to the vibration sensor 6a starts with the output of the start signal to the vibrator drive circuit '2.

At this time, the signal 41 is sent from the vibrator drive circuit 2 to the vibrator 4.
is applied.

In response to this signal, the ultrasonic vibration transmitted from the vibration bender 3 to the vibration transmission plate 8 is detected by the vibration sensor 6a after traveling for a time tg corresponding to the distance to the vibration sensor 6a. A signal indicated by 42 in the figure indicates a signal waveform detected by the vibration sensor 6a.

By the way, the vibration used in the example is a plate wave,
Therefore, the relationship between the envelope 421 and the phase 422 of the detected waveform with respect to the propagation distance within the vibration transmission plate 8 changes during vibration transmission according to the transmission distance.

Here, the speed at which the envelope 421 advances, that is, the group velocity, is Vg, and the phase velocity of the phase 422 is Vp. The distance between the vibration sensor 6a and the vibration sensor 3 can be detected from the difference between the group velocity Vg and the phase velocity Vp.

First, focusing only on the envelope 421, its velocity is Vg, and when a point on a certain waveform, for example a peak, is detected as in the signal shown by 43 in the figure, the distance between the vibration vent 3 and the vibration sensor 6a is d is the vibration transmission time tg, and d=Vg −tg...
(2) Although this equation relates to one of the vibration sensors 6a, the distances between the other two vibration sensors 6b, 6c and the vibration pen 3 can also be expressed using the same principle.

Furthermore, in order to determine coordinate values with higher precision, processing based on phase signal detection is performed.

The time from a specific detection point of the phase waveform signal 422, for example, vibration application to a zero crossing point after passing the peak, is tp(
A window signal 44 of a predetermined width is generated using the signal 43, and a phase signal 42 is generated.
2), the distance between the vibration sensor and the vibration pen becomes d=n·λp+Vp-tp...■. Here, λp is the wavelength of the elastic wave, and n is an integer.

The above integer n is calculated from the above equations ■ and 0 as n = [(Vg -tg -Vp -tp)/λp
+17N]...It is expressed as ■.

Here, N is a real number other than 0, and an appropriate value is used.

For example, if N=2, n can be determined if it is within ±1/2 wavelength. Set n calculated as above to 0
By substituting into the formula, the vibration pen 3 and the vibration sensor 6a
The distance between the vibrating pen 3 and the vibration sensors 6b, 6c
The distance between can be measured accurately.

The signals 43 and 45 for measuring the two vibration propagation times tg and tp mentioned above are generated by the signal waveform detection circuit 9, and this signal waveform detection circuit 9 is configured as shown in FIG.

In FIG. 5, the output signal of the vibration sensor 6a is amplified to a predetermined level by a preamplifier circuit 51. In FIG. The amplified signal is input to the envelope detection circuit 52, and only the envelope of the detection signal is extracted. The timing of the peak of the extracted envelope is detected by the envelope peak detection circuit 53. The peak detection signal is formed into a signal Tg (signal 53), which is an envelope delay time detection signal of a predetermined waveform, by a Tg signal detection circuit 54 composed of a mono multivibrator or the like, and is input to the arithmetic control circuit 1.

Moreover, this signal Tg is applied to the monostable multivibrator 55 (
After passing through a comparator level supply circuit 56 (generating a signal 44 with a predetermined pulse width) and a comparator level supply circuit 56 (generating a predetermined threshold value), it is supplied to a comparator Tp detection circuit 58 for comparison with the original signal delayed by a delay time adjustment circuit 57. . The comparator Tp detection circuit 58 supplies the phase delay time signal Tp to the arithmetic control circuit 1.

Note that the circuit described above is for the vibration sensor 6a, and the same circuit is provided for the other vibration sensors 6b and 6c.

Therefore, if the number of sensors is generalized to h, then h detection signals of envelope delay times Tgl to h and phase delay times Tpl to h are manually input to the arithmetic control circuit 1.

Then, in the arithmetic control circuit 1, the above Tgl~h, Tpl
~h signals are inputted from the input port 35, and the time value (count value) of the timer 33 is taken into the latch circuits 34a to 34C using each timing as a trigger. Since the timer 33 is started in synchronization with the driving of the vibrating pen, the latch circuits 34 to 34c will latch data indicating the respective delay times of the envelope and phase of each of the vibration sensors 6a to 6C. .

<Explanation of Coordinate Position Calculation (FIG. 6)> Next, the principle of actually detecting the coordinate position on the vibration transmission plate 8 by the vibrating ben 3 will be explained.

Now, the coordinates of the vibration sensor 6a on the vibration transmission plate 8 are S, (O
, O), that is, the origin, and the coordinate positions of the vibration sensors 6b and 6c are S b (X, 0) and S c (0, Y). Then, let the coordinates of the vibration Ben be P (x, y).

Based on the principle explained earlier, if the distances between the vibration vent 3 and each of the vibration sensors 6a to 6C are respectively d and ~de, the obtained P (x, y) can be calculated using the following formula from the Pythagorean theorem. It becomes like this.

Here, "X" and "Y" are the horizontal and vertical distances of the vibration sensors 6b and 6c from the vibration sensor 6a.

In the manner described above, the position coordinates of the vibrating ben 3 can be detected in real time.

Explanation of the correction process (FIGS. 7 and 8)> Next, the correction process in this apparatus for detecting coordinate positions using the above-described configuration and principle will be described below.

As explained earlier, the relationship between group delay time tg and phase delay time tp is shown in FIG. 8, with time t on the horizontal axis and vibration transmission distance from the input point to the vibration sensor on the vertical axis. become. The circuit delay time et is always included even at the distance "0", and the curve (straight line) of each delay time is offset to the right of the graph.

That is, the latch circuit 34 in the arithmetic control circuit 1 of the embodiment
The vibration transmission time latched in a to 34c includes the circuit delay time et and the phase offset time tOf.

The same amount of error caused by these is always included when the vibration is transmitted from the vibration vent 3 to the vibration transmission plate 8 and the vibration sensors 6a to 6c.

Therefore, for example, let R be the distance from the position of the mark 8a on the vibration transmission plate 8 to the vibration sensor 6a, and let t be the measured vibration transmission time from the mark 8a to the vibration sensor 6a.
g'r, tp'r, and vibration sensor 6a from mark 8a.
If the true transmission times are tgr and tpr, then using the circuit delay time et and phase offset tof, tg'r=tgr+et...tp
'r=tpr +et+tof''・■ There is a relationship.

On the other hand, the actual measured values tg'r and tp'p at any input point P are similarly tg p=tgp +et...■tp
p=tpp +et+tof...■.

Then, finding the difference between ■ and ■ and between ■ and ■, tg'p-rg'r = (tgp+et)-(tgr +et)=tgp-
tgr tpp-tpp = (tpp +et+tof) -(tpr +et
+tof) =tpp-tpr, and the circuit delay time e and phase offset tof included in each transmission time are removed, and the true distance between the position of the mark 8a and the human power point P from the sensor 6a is calculated as follows. The difference in vibration transmission time can be determined.

Then, by applying the obtained time difference to the above-mentioned equations (2) and 0, the difference in distance between the two points and the vibration sensor 6a can be obtained. Furthermore, since the distance 11iR between the mark 8a and the vibration sensor 6a is known (stored in the ROM 31a), the input point P can be determined by summing the previously determined distance difference and its R. The distance between the vibration sensor 6a and the vibration sensor 6a can be calculated.

Using the same principle, the distance between each of the vibration sensors 6b and 6c and the input point P can be calculated, so if the above coordinate position calculation formula is used, the coordinate position of the input point P can be calculated. can.

In this way, the correction values tg'r and tp'r obtained by inputting the coordinates to the position of the mark 8a are displayed on the display 11 at a predetermined timing (for example, when the power is turned on to the device itself), prompting the user to operate the correction values tg'r and tp'r. It would be more ideal if this operation were to be performed by the operator, or at predetermined intervals during the operation. In addition, the latest correction value is RAM31
It is sufficient to store it in b.

In any case, by always inputting such a correction value, it is possible to appropriately correct changes in circuit delay time and the like caused by environmental changes and the like. If the correction value is taken in at the time of factory shipment and the data is stored in a non-volatile memory or the like, it becomes possible to appropriately correct at least the circuit delay and phase offset that vary from device to device.

By the way, regarding the period of this correction value input, if the accuracy of the manual coordinate position is important, the shorter the interval, the better.However, this time, conversely, the correction value input becomes more frequent. As a result, the problem of poor operability occurs.

Therefore, in the embodiment, this correction value input is performed only when it is necessary to update the correction value due to environmental changes.

Specifically, when the device is powered on, the microcomputer 31 first reads the temperature data detected by the temperature sensor 12 fixed to the vibration transmission plate 8! 10 is input from the boat 37 and stored in the RAM 31b,
The operator is prompted to input a correction value (instruction input using the vibrating ben 3 of the mark 8a). Then, the obtained correction value is stored in the RAM 3 lb together with the corresponding temperature information.

Thereafter, the microcomputer executes coordinate input processing, during which time it constantly reads temperature information and checks the difference with the already stored temperature information.

Then, only when the difference exceeds the allowable range T [t], the buzzer 13 is sounded to prompt (notify) the operator to input a new correction value. Note that this tolerance range T is defined as the amount of temperature that affects the delay of electric circuits, etc.

Following the warning from the buzzer 13, the operator inputs the coordinates at the mark 8a in the same manner as described above, and updates the coordinates with new correction values and temperature information.

In this way, since the correction value is no longer obtained at regular intervals, it is possible to improve the operability.

Incidentally, in order to obtain the correction value, the operator is required to input the coordinates accurately to the position of the mark 8a.

However, by using the method described below, it becomes possible to input coordinates for inputting correction values at arbitrary positions.

That is, the coordinates are determined from a hyperbolic function using the delay time difference between the sensors, and the delay time is corrected from the determined value.

Coordinate determination based on the delay time difference is performed by, for example, arranging vibration sensors S0 to S as shown in Fig. 7, and assuming that the intersection point 0 of the straight lines connecting the opposing sensors is the origin, the difference in distance between the sensors So and S is determined by If the difference in distance between a, S, and SS is b, the designated point P (x, y) can be found as the intersection of hyperbolic functions as shown in the following equation.

However, c'-4X2-a"d' = 4Y" - b2 c'd" - a"b'>0 The coordinates of any human power point can be determined by these equations. If the vibration transmission time to each sensor at this time is stored in the RAM 11b as a correction value, the above correction process can be performed.

According to such a method, it is possible to obtain a correction value at an arbitrary position, so that even a user can easily perform correction.

In addition, at this time, as explained earlier, the temperature is detected and
A correction value is obtained based on the temperature.

It is possible to obtain this correction value periodically or irregularly (for example, when specifying a certain area while inputting coordinates), but it is not possible to take measures when no input operation is performed for a long time. That's because there isn't.

In other words, even when restarting the input operation after interrupting the input operation for a long time, a warning will be issued if the temperature rises to a certain level, and by consciously performing the above arbitrary input correction,
It is possible to prevent uncorrected data when input is restarted. Furthermore, it becomes possible to completely correct changes in circuit delay time due to temperature changes and the like.

However, as you can see from Equation 0.0, calculations using a microprocessor are extremely complex, so from the viewpoint of accuracy and calculation speed, the method described above (detected) is not recommended for real-time coordinate determination. It is advantageous to input the coordinates of the position of the mark 8a when it is determined that it is necessary to update the correction value based on the temperature.

It goes without saying that even with the sensor arrangement as shown in FIG. 7, coordinates can be determined using the Pythagorean theorem as described above.

<Description of Other Embodiments> In the above embodiments, a buzzer was used as a warning means, but it is clear that other sounding bodies may be used.

Further, for example, a warning may be displayed on the display 11 or the like, or a visual notification may be made using a light emitting device such as an LED, or a combination of these may of course be used.

Further, in the above embodiment, the temperature sensor 12 is attached to the vibration transmission plate 8, but the circuit delay due to the temperature characteristics of the electric circuit is as much as or more than the influence due to the temperature characteristics of the vibration transmission plate 8, the vibration sensor 6, etc. Since the time fluctuation is also large, this temperature sensor 12 may be attached to an electric circuit section (for example, near the signal waveform detection circuit 9). Moreover, these temperature sensors may be attached at several locations.

Note that the temperature sensor 12 is not limited by this structure itself, as it may be a thermistor or the like as long as it has a predetermined range and accuracy.

Moreover, in order to issue a warning and avoid false detection when the temperature fluctuation exceeds the specification allowable limit, a configuration may be adopted in which no amount other than the input operation is applied to the position of the mark 8a.

As described above, according to this embodiment, it is possible to minimize the number of operations required to correct vibration detection time that varies in response to temperature changes.

[Effects of the Invention] As explained above, according to the present invention, it is possible to easily correct the vibration arrival time due to reaction fluctuations of each circuit element related to temperature-dependent vibration arrival detection, and moreover, with the minimum necessary operations. becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the coordinate input device of this embodiment, and FIG. 2 is a diagram showing the structure of a vibrating pen. Fig. 3 is a diagram showing the internal configuration of the arithmetic control circuit in the embodiment, Fig. 4 is a diagram for explaining distance measurement between the vibrating pen and the vibration sensor, and Fig. 5 is the signal waveform detection circuit in the embodiment. Figure 6 is a diagram for explaining the principle of coordinate position calculation; Figure 7 is a diagram showing the arrangement position of the vibration sensor when performing correction using an arbitrary coordinate input point; FIG. 8 is a diagram showing the relationship between the group velocity detection signal Tg and the phase velocity detection signal tp over time and distance. In the figure, 1... Arithmetic control circuit, 2... Vibrator drive circuit, 3... Vibrating pen, 4... Vibrator, 6a to 6C...
・Vibration sensor, 7... Vibration isolating material, 8... Vibration transmission plate,
8a...Mark, 9...Signal waveform detection circuit, 10.
...Display drive circuit, 11...Display,
12...Temperature sensor, 13...Buzzer 31...
Microcomputer, 33...Timer, 34a-3
4c... Latch circuit, 35... Detection signal input port, 36... Judgment circuit, 37... I10 port. Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] A coordinate input device that detects vibration input from a vibrating pen using a plurality of vibration sensors provided on a vibration transmission plate, and detects the position of the vibrating pen from the vibration transmission time to each vibration sensor, A temperature detection means for detecting temperature; and a determination based on the temperature information detected by the temperature detection means as to whether or not it is necessary to correct the vibration arrival time due to reaction fluctuations of each circuit element related to vibration arrival detection. A coordinate input device comprising: a determining means; and a notifying means for notifying a request for a predetermined coordinate input operation related to correction processing when the determining means determines that correction is necessary.