JPH07210302A - Coordinate input device - Google Patents

Abstract

PURPOSE:To overcome the instability of vibration detection due to that vibration is transmitted in two vibration modes and to enable stable coordinate input to be carried out. CONSTITUTION:The peak of signals obtained by detecting a first vibration pulse is held by a peak hold circuit 4b-1 and the value is voltage-divided by a fixed resistor 4b-4 and a variable resistor 4b-3 and inputted to a comparator 4b-2. The signal by a second pulse is inputted to the comparator 4b-2 and compared with the output of the peak hold circuit 4b-1. As a result, rectangular waves with a window are outputted only in a period when the second signal becomes equal to or more than a prescribed value. For the signals by the vibration pulses, a zero-cross point is detected within the period, the time from a vibration source to a detection point is measured with the time as the arrival time of vibration and coordinates are calculated based on it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects, for example, elastic wave vibration input from a vibrating pen by a sensor provided on a vibration transmitting plate, and elastic wave vibration input from the vibrating pen to the vibration transmitting plate. The present invention relates to a coordinate input device that detects the coordinates of a vibration input point by a vibrating pen based on the transmission time of, and inputs the coordinates to another device or the like.

[0002]

2. Description of the Related Art A coordinate input device using ultrasonic waves contacts a vibration transmission plate with a vibrating pen and transmits the input vibration on the vibration transmission plate until it reaches a sensor provided on the vibration transmission plate. The coordinates of the contact position of the vibrating pen are calculated based on the delay time.

As described in Japanese Patent Application Laid-Open No. 61-149742 and Japanese Patent Application Laid-Open No. 61-245474, elastic vibration used in this case is a so-called plate wave elastic wave. Therefore, it is less susceptible to surface conditions (scratches, etc.) than surface waves.

As a propagation mode of the plate wave elastic wave, a mode called symmetric wave (S mode) and asymmetric wave (A mode) is known. In particular, when the order is used and the mode is the zero-order mode, it is called S0 wave and A0 wave. In the example of the above-mentioned document, the A0 mode is used.

The A0 mode is a wave in which the group velocity, which is the velocity of propagation of the wave itself, and the phase velocity, which is the velocity at which the phase of the wave propagates, are different. In the above example, the group delay time and the phase due to the group velocity are different. The coordinate input device is configured by using the phase delay time due to the velocity.

FIG. 11 shows the configuration. The vibration input from the vibration pen 105 is transmitted to the vibration transmission plate 108.
Propagating in the inside as a plate elastic wave, and each sensor 106a-10
6d detected. The detected vibration is the amplifier 1
09-1 and a filter 109-2, and a group delay time (hereinafter Tg) detection Tg detection circuit 109-3 and a phase delay time (hereinafter tp) detection Tp detection circuit 1
It is distributed to 09-4. The signal waveform here is shown in FIG.
Shown in.

The Tg detection circuit 109-3 detects the envelope 421 of the signal, detects a predetermined point on the envelope, and generates a trigger signal. The predetermined point referred to here can be detected as a signal 49, for example, by detecting the zero-cross point of the signal 43 that has been differentiated twice as the inflection point of the signal waveform. By performing detection in the first half of the signal waveform like inflection point detection as described above, in the configuration as shown in FIG.
The structure is less likely to be affected by reflected waves from the end portion, the vibration isolator 107, etc., which contributes to downsizing of the area outside the input area.

On the other hand, also in Tp detection, it is desirable to detect at the front end of the signal waveform in order to avoid the influence of reflected waves as much as possible. Therefore, conventionally, a threshold level 441 is provided for the detection signal waveform 44 processed by a bandpass filter or the like, and the rising zero crossing point of the first phase after exceeding the threshold value is detected as a signal 47 and a trigger signal is generated. It was configured to occur.

In such a configuration, the detection point can be set at the front end of the signal waveform by setting the threshold level as low as possible.

Further, in such a structure, the amplitude of the propagating vibration is attenuated as the distance between the vibration sensor and the vibrating pen increases.

By increasing the size or increasing the density of the structure, the difference between the input level near the sensor and the level at the farthest point of the effective area becomes large. For example, sensor 106-d
, The farthest point is point B, and the nearest point is point A.

On the other hand, a technique has been proposed in which an amplifier whose amplification factor changes with the propagation time is provided to prevent the occurrence of an error due to amplitude fluctuation. Further, Japanese Patent Publication No. 58-16509 discloses a technique for detecting by changing a detection threshold exponentially with respect to a propagation delay time.

[0013]

However, it is difficult to strictly control the threshold value and the amplification factor of the amplifier with respect to the propagation delay time. Further, when a plate wave is used, the frequency is simply changed. Each time the propagation speed changes, it is necessary to change the amplification rate and the threshold change rate each time, which includes accuracy deterioration due to frequency variations, difficulty in design change, and cost increase factors such as adjustment.

The detection signal is, as shown in FIG.
In addition to the A0 wave to be detected, a small amount of S0 signal is also detected. When the level ratio of A0 and S0 is sufficiently large, there is no influence on the detection, but as described above, the influence cannot be ignored as the difference in signal level between the input points increases. That is, when the setting of the change rate such as the amplification rate or the threshold value is not appropriate, S0 is detected instead of A0, which causes a problem of erroneous detection.

The present invention has been made in view of the above conventional example, and an object of the present invention is to provide a stable and highly accurate coordinate input device which prevents the detection of unnecessary signals.

[0016]

In order to achieve the above object, the coordinate input device of the present invention has the following structure.
That is, a coordinate input device that detects a vibration input to a vibration transmission member to calculate a vibration input position and uses coordinates of the calculated position as input coordinates, the input device inputting vibration, and the vibration transmission. Detection means for detecting the vibration transmitted to the member and outputting it as a signal, and comparing means for comparing the signal output from the detection means with the signal based on a value of a predetermined ratio with respect to the peak of the signal. And, as a result of the comparison by the comparison means, a period in which the signal exceeds the reference is set as a period for measuring the timing at which vibration reaches,
The measuring means measures the arrival time of the vibration, and the calculating means calculates the coordinates of the point at which the vibration is input by the input means based on the time measured by the measuring means.

Further, the coordinate input device detects the vibration input to the vibration transmitting member, calculates the vibration input position, and uses the coordinates of the calculated position as the input coordinates, and input means for inputting the vibration. Detection means for detecting the vibration transmitted to the vibration transmission member and outputting it as a signal, and based on the signal output by the detection means, compared with the signal based on a value of a predetermined ratio with respect to the peak of the signal Comparison means to
As a result of the comparison by the comparison means, a period in which the signal exceeds the reference is delayed by a predetermined time, and a timing at which vibration arrives is measured to measure the arrival time of the vibration, and the measurement means measures the arrival time of the vibration. And a calculation unit that calculates the point-and-coordinates at which the vibration is input by the input unit based on the calculated time.

A coordinate input device that detects a vibration input to the vibration transmitting member, calculates a vibration input position, and uses the coordinates of the calculated position as input coordinates, and an input means for inputting vibration. A detection unit that detects the vibration transmitted to the vibration transmission member and outputs it as a signal, a peak detection unit that detects the peak of the signal based on the signal output by the detection unit, and a peak by the peak detection unit. A delay unit for generating a timing signal delayed by a predetermined time from the timing of detecting the signal, and a signal output by the detecting unit after the timing delayed by the delay unit with reference to the peak of the signal detected by the peak detecting unit. And comparing the result of the comparison by the comparing means with the period when the signal exceeds the reference, the timing when the vibration reaches. As the period of, comprising measuring means for measuring the arrival time of the vibration, and a calculation means based on the time measured by said measuring means, calculates the O coordinate points input of vibration by said input means.

[0019]

With the above structure, the vibration is detected, the predetermined ratio to the peak of the signal is compared with the detected signal as the threshold value, the arrival time of the vibration is measured within the period larger than the threshold value, and based on the measurement result. Calculate the input coordinates of vibration.

[0020]

First Embodiment FIG. 2 shows the structure of a coordinate input device which is a preferred embodiment of the present invention.

In the figure, reference numeral 1 is an arithmetic control circuit for controlling the entire apparatus and calculating the coordinate position. Reference numeral 2 denotes a vibrator drive circuit for vibrating the pen tip of the vibrating pen 3. Reference numeral 8 is a vibration transmission plate made of a transparent member such as acrylic or glass plate. Coordinates are input by the vibration pen 3 by touching the vibration transmission plate 8. And in fact,
The vibrating pen 3 is used to specify the inside of the area (hereinafter referred to as the effective area) indicated by the symbol A indicated by the solid line in the figure. A vibration damping material 7 is provided on the outer periphery of the vibration transmitting plate 8 for preventing (reducing) the reflected vibration from returning to the central portion. The vibration sensors 6a to 6d for converting to are fixed.

Reference numeral 9 denotes a signal waveform detection circuit for outputting to the arithmetic and control circuit 1 a signal indicating that vibration has been detected by each of the vibration sensors 6a to 6d. Reference numeral 11 is a display such as a liquid crystal display capable of displaying in dot units, and is arranged behind the vibration transmission plate. Then, by driving the display drive circuit 10, it becomes possible to display a dot at a position traced by the vibrating pen 3 and see it through the vibration transmission plate 8 made of a transparent member such as glass or acrylic. There is.

The vibrator 4 built in the vibrating pen 3 is driven by the vibrator driving circuit 2. The drive signal for the vibrator 4 is supplied as a low-level pulse signal from the arithmetic control circuit 1, amplified by the vibrator drive circuit 2 with a predetermined gain, and then applied to the vibrator 4.

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

Here, the vibration frequency of the vibrator 4 is selected to a value capable of generating a plate wave on the vibration transmission plate 8 such as glass. Further, when driving the vibrator, a mode in which the vibration transmitting plate 8 vibrates in the vertical direction of FIG. 2 is selected. Further, by setting the vibration frequency of the vibrator 4 to the resonance frequency including the pen tip, efficient vibration conversion can be performed.

The elastic wave transmitted to the vibration transmitting plate 8 as described above is a plate wave, and has an advantage that it is less susceptible to scratches and obstacles on the surface of the vibration transmitting plate as compared to surface waves. .

<Description of Arithmetic and Control Circuit> In the above-mentioned configuration, the arithmetic and control circuit 1 has a predetermined cycle (for example, 10 ms).
Every time), a signal for driving the vibrator 4 in the vibrating pen 3 is output from the vibrator driving circuit 2 and the internal timer (which is composed of a counter) starts timing. The vibration generated by the vibrating pen 3 is applied to the vibration sensor 6a.
It arrives with a delay according to the distance up to 6d.

The signal waveform detection circuit 9 includes the vibration sensors 6a.
The signal from 6d is detected, and the signal which shows the vibration arrival timing to each vibration sensor is produced | generated by the waveform detection process mentioned later. The arithmetic control circuit 1 inputs this signal for each sensor, detects the vibration arrival time to each of the vibration sensors 6a to 6d, and calculates the coordinate position of the vibration pen.

Further, the arithmetic control circuit 1 drives the display drive circuit 10 based on the calculated position information of the vibrating pen 3 to control the display by the display 11, or the external device by serial communication or parallel communication. The coordinates are output to (not shown).

FIG. 3 is a block diagram showing a schematic structure of the arithmetic and control circuit 1 of the embodiment. The respective constituent elements and the operation outline thereof will be described below.

In the figure, 31 is a microcomputer for controlling the arithmetic control circuit 1 and the coordinate input apparatus as a whole, and an internal counter, a ROM storing operation procedures, a RAM used for calculations and the like, and a nonvolatile memory storing constants and the like. It is composed of a sex memory.

Reference numeral 33 is a counter for counting a reference clock (not shown). When a start signal for starting the driving of the vibrator 4 in the vibrator pen 3 is input to the vibrator drive circuit 2, the counter is started. To do. As a result, the start of timing and the vibration detection by the sensor are synchronized, and the sensor (6a
It is possible to measure the delay time until the vibration is detected by (6d).

The clocked value of the counter 33 depends on the detection signal input to the detection signal input circuit 35, and the latch circuits 34a ...
It is stored in 34d. When the microcomputer 31 detects the output of the determination circuit, which indicates that the detection signals are aligned within a predetermined time, the microcomputer 31 reads the content of each latch circuit and performs calculation.

What is detected here corresponds to the group delay time (Tg) and the phase delay time (Tp) of the vibration reaching the sensor 6.

The detection signal is output by the signal wave detection circuit 9 having the configuration shown in FIG. The configuration of FIG. 5 is for the sensor 6a, but the same applies to the sensors 6b to 6d.

The output signal of the vibration sensor 6a is amplified to a predetermined level by the preamplifier circuit 51. The bandpass filter 511 removes the extra frequency component of the detected signal from the amplified signal, and the amplified signal is input to the envelope detection circuit 52 including, for example, an absolute value circuit and a low-pass filter. Is taken out. The extracted envelope signal is differentiated by the twice differentiating circuit 53. The tg signal detection circuit 54
A signal tg which is a delay time detection signal is formed by detecting a zero-cross point after exceeding a predetermined level of the envelope, which is composed of a mono-multivibrator or the like, and is input to the detection signal input circuit 35 in the arithmetic control circuit 1. To be done. The threshold for detecting the predetermined level of the envelope in the tg detection circuit 54 is determined as shown in FIG.
As shown in FIG. 12, when the maximum amplitude level ratio between the S0 wave and the A0 wave of the vibration waveform is, for example, about 5%,
The threshold level may be set to a value larger than 5% of the magnitude of A0 amplitude.

However, as described above, since the amplitude of the vibration waveform changes depending on the distance from the sensor and the input writing pressure, a fixed threshold, for example, the A0 wave amplitude at the farthest point from the sensor is used as the basis. When the threshold level is determined as above, the S0 wave may be detected near the sensor. On the other hand, if the threshold value is determined as shown in FIG. 1, the threshold value can be determined for the level of the envelope signal during writing.
The method shown in FIG. 1 is as follows.

That is, for example, the threshold level is now S0.
The value is set to 10% as a value larger than 5% which is the / A0 ratio. And in order to detect one vibration, it is actually 2
Use two vibrations. When actually writing, a plurality of vibration pulses are input by one input, but if the vibration detection period for one input is called a sampling period, there is little variation in writing pressure within each sampling period. The same waveform can be detected at the second time and the second time. The A0 wave amplitude V1 detected by the first driving is held by the peak hold circuit 4b-1 as shown in FIG.
Then, the second hold is performed to drive the peak hold circuit 4
The output V1 / 10 obtained by dividing the output of b-1 by the resistors 4b-4 and 4b-3 is used as a threshold value to be input to the comparator 4b-2, and the value is compared with the signal by the second pulse. Performs signal detection. In this way, as the output of the comparator 4b-2, a rectangular wave that is the result of comparison between the threshold value and the signal waveform is obtained. This becomes the window signal. Here, the resistor 4b-
If 4 is a fixed resistance, the ratio of the partial pressure can be determined by setting the value of the resistance 4b-3 to an appropriate value. As the ratio of this partial pressure, the S0 / A0 ratio described above is set.
Since this is 10% in this example, if the value of the resistor 4b-4 is R, R / 9 is set as the resistor 4b-3. In this way, if the output signal of the comparator 4b-2 is used as the window signal and signal detection (for example, zero cross detection) is performed based on this result, Tg detection for the A0 wave becomes possible.

The partial pressure ratio may be a value determined based on the S0 / A0 ratio as described above. If such detection is also used for subsequent signal detection, the A0 signal can be reliably detected even when the level changes as shown in FIG.

FIG. 1 shows how the four pulses shown in (a) are input from the vibrating pen. Vibration pulse 1a-1
d is detected by one sensor propagating through the vibration transmission plate, and the vibration envelopes 2a, 2 corresponding to the pulses 1a, 1b.
Pulses 1c and 1d detected by one sensor a as b
The other sensors b whose distance from the vibration source is farther than the sensor a are detected as the envelopes 2c and 2d of the vibration corresponding to.

First, the signal 2a is peak-held and its value V1 is held. The next signal 2b is compared with Vth1 = V1 / 10 by the comparator to generate the window signal 3a. The same applies to the signals 2c and 2d, but since this signal is a signal detected by the sensor b farther than the sensor a, it is weaker than the signals 2a and 2b. The threshold value Vth2 for this signal is V2 / 10, and the window signal 3b is generated using this value. In this way, the threshold can be raised or lowered according to the strength of the detected signal to generate the window signal.

The peak hold circuit is initialized by the reset signal from the arithmetic control unit 1 when the sampling by the double driving is completed, and prepares for the next detection.

Reference numeral 55 is a Tp signal detection circuit, which is composed of a comparator and the like, and forms a pulse signal of a portion of the output of the bandpass filter 511 which exceeds a threshold value of a predetermined level. If this threshold value is also determined by the same configuration as the above Tg, a stable A0 wave can be detected. This phase delay time signal tp is also supplied to the arithmetic control circuit 1.

At this time, the threshold circuit for detecting Tg and Tp may be independently provided as described above, but may be shared to reduce the circuit scale and the like.

<Explanation of Vibration Propagation Time Detection> The microcomputer 31 receiving the data set signal reads the delay times Tg and Tp stored in the respective latches using the select signal and stores them in the memory.

The case of the vibration sensor 6a will be described below, but the same applies to the other vibration sensors 6b, 6c and 6d.

The measurement of the vibration transmission time to the vibration sensor 6 is
It starts at the same time when the start signal is output to the oscillator drive circuit 2. At this time, the drive signal 1-1 is applied from the vibrator drive circuit 2 to the vibrator 4. The ultrasonic vibration transmitted from the vibration pen 3 to the vibration transmission plate 8 by this signal 1-1 is detected by the vibration sensor 6 after traveling for a time tg corresponding to the distance to the vibration sensor 6a.

Since the vibration used in this embodiment is a plate wave, the relationship between the propagation waveform in the vibration transmission plate 8 and the envelope of the detected waveform and the phase depends on the transmission distance during vibration transmission. Change. Here, the group velocity is Vg and the phase velocity is Vp. This group velocity V and phase velocity Vp
Therefore, the distance between the vibration pen 3 and the vibration sensor 6a can be detected.

First, the speed is Vg with respect to Tg, and the distance d between the vibrating pen and the vibration sensor 6a is given by d = Vg.tg (1). This equation relates to one of the vibration sensors 6a, but the same equation applies to the other three vibration sensors 6a.
The distance between 6d and the vibrating pen 3 can be similarly expressed.

Further, processing based on the detection of the phase signal is performed.

When the distance between the vibration sensor and the vibration pen is calculated using the obtained Tp signal, d = n.lambda.p + vP.tp (2) Here, λp is the wavelength of the elastic wave, and n is an integer.

From the above equations (1) and (2), the above integer n
Can be expressed as n = [(Vg · tg−Vp · tp) / λp + α] (3) [].

Here, α determines the margin for the calculation of n, and an appropriate value is used. For example, α = 1
If it is / 2, Vg · t within ± 1/2 wavelength with respect to the reference
If g varies, n can be determined. By substituting n obtained as described above into the equation (2), the distance between the vibration pen 3 and the vibration sensor 6a can be accurately measured.

<Description of Coordinate Position Calculation (FIG. 6)> Next, the principle of actually detecting the coordinate position on the vibration transmission plate 8 by the vibration pen 3 will be described with reference to FIG.

Now, in the vicinity of the midpoint of four sides on the vibration transmission plate 8, 4
When the two vibration sensors 6a to 6d are provided at the positions S1 to S4, the linear distances da to dd from the position P of the vibrating pen 3 to the positions of the respective vibration sensors 6a to 6d are calculated based on the principle described above. You can ask. Further, the arithmetic control circuit 1 can obtain the coordinates (x, y) of the position P of the vibrating pen 3 from the Pythagorean theorem based on the linear distances da to dd as in the following equation.

X = (da + db) · (da−db) / 2X (10) y = (dc + dd) · (dc−dd) / 2Y (11) where X and Y are the distances between the vibration sensors 6a and 6b, respectively. , The distance between the vibration sensors 6c and 6d. As described above, the position coordinates of the vibrating pen 3 can be detected in real time.

As described above, the vibration transmitted to the vibration transmission plate is detected, and the delay time from the vibration input to the detection is calculated,
By calculating the coordinates of the position where the vibration is input based on that, it is possible to improve the input accuracy without detecting unnecessary vibration regardless of the position of the vibration input point on the vibration input surface.

[0058]

[Second Embodiment] When the S0 / A0 ratio is large, or when highly accurate coordinate detection is performed, detection that avoids the influence of S0 is effective. As a second embodiment, a coordinate input device that enables highly accurate coordinate detection in such a case will be described.

FIG. 7 shows the relationship between the distance from the sensor and S0 and A0.

At a short distance from the sensor, the S0 wave is included in the A0 wave (FIG. 7 (a)). Since the propagation speed of the S0 wave is faster than that of the A0 wave, the two waves are separated as the distance becomes longer (FIG. 7C). Even in the case of FIG. 7A, S
When the influence of the 0 / A0 ratio is smaller than the desired accuracy, there is no problem, and in the cases as shown in FIGS. 7B and 7C, S0
In order not to detect the wave, it is possible to detect the wave by using the configuration of the first embodiment described above.

On the other hand, as shown in FIG. 7A, S0 / A
When the 0 ratio is large, the phase signal delay time (T
p) may be affected. Therefore, it is required to detect by excluding the influence range of S0.

FIG. 8 shows the detection method.

For the detection signal, first, for example, at a point away from the sensor, detection is performed with a threshold value of such a level that if it overlaps with the A0 wave as it is, the detection is affected. When this detection is performed, the threshold value of the detection signal is detected with a delay of Ts0, which is an influence of S0 for a predetermined time.

In the actual circuit configuration, as shown in FIG. 9, a detection signal is first input to the comparator 9-1 and threshold detection is performed at the S0 detection level. The comparator signal generated by the detection is input to the delay circuit 9-2 composed of the capacitor C, the resistor R, the delay line and the like. Here, the signal delayed by Ts0 time is input to the one-shot FF 9-3 and output as the enable signal of the comparator 9-4 for generating the window signal. When the comparator 9-4 receives this enable signal, it detects a signal with a predetermined detection threshold value and, as a result, generates a window signal. One shot FF9-
3 is reset by the next detection cycle to prepare for the detection operation.

By generating the window signal with such a configuration, it is possible to detect the A0 wave while eliminating the influence of the S0 wave. Therefore, FIGS. 7 (a), (b), (c)
Even in each state, highly accurate detection can be performed without the influence of S0.

In this embodiment, the threshold value is fixed, but as a matter of course, as in the first embodiment,
The threshold value may be determined from the level by performing driving a plurality of times.

Again, in the first embodiment, A0 / S
Although the level is set so that the S0 wave is not detected based on the 0 ratio, the effect of the second embodiment is enhanced by setting the value that surely detects the S0 wave.

[0068]

[Third Embodiment] In the second embodiment, the threshold value for A0 wave detection is fixed and determined, but by setting this value based on the S0 wave level, as shown in FIG. In the case where two waves are separated, it is possible to prevent malfunction between the waves and to detect at the head of the wave that is not easily affected by reflection or the like regardless of the level reduction.

FIGS. 10A and 10B show a circuit for generating a detection waveform and a window signal, respectively.

A threshold value is set in advance for the level at which S0 can be detected with respect to the detection signal waveform, and the comparator 11-2 first sets S
Detect 0 waves. This comparator output is a delay circuit
It is inputted as an enable signal to the window signal generating comparator 11-5 via the one-shot FF 11-3.
The threshold value Vth of the comparator 11-5 is created by holding the detection signal waveform by the peak hold 11-4, and changes like the signal 11-1 with a delay from the actual signal change.
By performing the comparator detection of the detection signal waveform based on the comparison level determined based on the S0 level, it is possible to detect the head portion of the A0 wave regardless of the signal level fluctuation. Furthermore, even for noise generated in the enable period of the comparator from S0 to A0,
A strong structure enables stable detection.

Although the envelope signal waveform has been described in each of the above embodiments, the present invention is not limited to this, and the window signal in Tp detection or the like may be a signal after passing the band pass filter or a signal passing through the filter. The configuration of the above embodiment is effective for signals that are not processed.

The present invention may be applied to a system composed of a plurality of devices, may be applied to a device from a single device, or may be achieved by supplying a program to the system or device. It goes without saying that it is also applicable.

[0073]

As described above, the coordinate input device according to the present invention has the effect of preventing the detection of unnecessary signals and enabling stable and highly accurate coordinate input.

[0074]

[Brief description of drawings]

FIG. 1 is an explanatory diagram of detection signal processing.

FIG. 2 is an overall configuration diagram of a coordinate input device.

FIG. 3 is an internal configuration diagram of an arithmetic control circuit in the embodiment.

FIG. 4 is a configuration diagram of a signal detection circuit.

FIG. 5 is a block diagram of a signal detection circuit.

FIG. 6 is a diagram showing a coordinate system of a coordinate system input device.

FIG. 7 is a relationship diagram of detection signals.

FIG. 8 is a detection vibration time chart.

FIG. 9 is a block diagram of signal processing.

FIG. 10 is a time chart of threshold value determination and a circuit configuration block diagram.

FIG. 11 is a diagram of a configuration example of a conventional example.

FIG. 12 is an explanatory diagram of a plate wave S0 mode and an A0 mode.

FIG. 13 is a time chart of signal processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arithmetic control circuit 2 Vibrator drive circuit 3 Vibration input pen 4 Vibrator 5 Pen tip 6a to 6d Vibration sensor 7 Vibration isolator 8 Vibration transmission plate 9 Signal waveform detection circuit

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Katsuyuki Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masaki Tokioka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Co., Ltd. (72) Inventor Hajime Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (5)

[Claims] 1. A coordinate input device which detects a vibration input to a vibration transmitting member, calculates a vibration input position, and uses coordinates of the calculated position as input coordinates, the input device inputting vibration. Detecting means for detecting the vibration transmitted to the vibration transmitting member and outputting it as a signal; and comparing the signal output from the detecting means with the signal based on a value of a predetermined ratio with respect to the peak of the signal. And a measuring unit for measuring the arrival time of vibration, wherein the period when the signal exceeds the reference as a result of comparison by the comparing unit is a period for measuring the timing when the vibration arrives, and the measuring unit for measuring the arrival time of vibration. A coordinate input device for calculating the coordinates of a point to which the vibration is input by the input device based on the calculated time. 2. The coordinate input device according to claim 1, wherein the predetermined ratio is determined based on a ratio of amplitudes of vibrations of two modes transmitted by the vibration transmission member. 3. A coordinate input device which detects a vibration input to a vibration transmitting member, calculates a vibration input position, and uses coordinates of the calculated position as input coordinates, the input device inputting vibration. Detecting means for detecting the vibration transmitted to the vibration transmitting member and outputting it as a signal; and comparing the signal output from the detecting means with the signal based on a value of a predetermined ratio with respect to the peak of the signal. Comparing means for measuring the arrival time of the vibration by delaying a period in which the signal exceeds the reference for a predetermined time as a result of the comparison by the comparing means, and measuring a timing when the vibration arrives in the period. A coordinate input device, comprising: a calculating unit that calculates a point-e coordinate at which the vibration is input by the input unit, based on the time measured by the measuring unit. 4. The predetermined time to delay is determined based on the time until one of the two modes of vibration transmitted through the vibration transmission member is attenuated. Coordinate input device. 5. A coordinate input device that detects a vibration input to a vibration transmission member, calculates a vibration input position, and uses coordinates of the calculated position as input coordinates, the input device inputting vibration. Detection means for detecting the vibration transmitted to the vibration transmission member and outputting it as a signal, peak detection means for detecting the peak of the signal based on the signal output by the detection means, and peak detection by the peak detection means A delay unit for generating a timing signal delayed by a predetermined time from the timing of detecting the signal, and a signal output by the detecting unit after the timing delayed by the delay unit with reference to the peak of the signal detected by the peak detecting unit. And a timing at which the vibration reaches a period during which the signal exceeds the reference as a result of the comparison by the comparing unit. As a period to be set, a measuring means for measuring the arrival time of the vibration, and a calculating means for calculating the point x coordinate at which the vibration is input by the input means based on the time measured by the measuring means are provided. Characteristic coordinate input device.