JPH06324790A - Coordinate input device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a compact and highly accurate coordinate input device. [Structure] A vibration transmitting plate 8 has vibration sensors 6 attached to both ends of one side thereof. 6 A vibration isolator 7 is attached to the other side. When the vibration is input to the vibration transmission plate 8 by the vibration pen 3, the direct wave of the vibration is detected by the sensors 6a and 6b, and the wave hitting the side on which the vibration isolator 7 is attached is significantly attenuated. Interference is suppressed. No vibration damping material is attached to the side where the sensor is attached, but the reflected wave does not reach the sensor. For this reason, it is possible to reduce the size of the device by the amount of the vibration isolator, and it is also possible to prevent the accuracy from decreasing due to the interference of the reflected waves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device, and more particularly to a coordinate input device for detecting designated point coordinates from vibration transmission time on a vibration transmission plate, which has a structure in which a vibration isolator is provided around the vibration transmission plate. The present invention relates to a coordinate input device.

[0002]

2. Description of the Related Art Conventionally, there has been a coordinate input device for inputting vibration to a vibration transmission plate by a vibrating pen having a piezoelectric element or the like, and detecting the coordinates of an input point by a plurality of vibration sensors provided on the vibration transmission plate. Are known.

Conventionally, in such a coordinate input device, in order to prevent deterioration of coordinate detection accuracy due to interference of a reflected wave from the end face of the vibration transmitting plate with a direct wave, as shown in FIG. The vibration-proof material was attached to the four sides. Then, in order to prevent the coordinate detection accuracy from deteriorating due to the interference of the reflected wave at the end surface of the vibration isolator mounted around the vibration transmission plate with the direct wave, the vibration sensor should be separated from this vibration isolator by a certain distance, and the coordinate detection However, the effective area that can be used without deterioration of accuracy is arranged at a position separated from the vibration sensor by a certain distance. On the other hand, a proposal to install the vibration sensor on the boundary surface (above) of the change in acoustic impedance was made in Japanese Patent Application No. 61-251599, which is a prior application by the applicant of the present application.

[0004]

However, as in the above-mentioned conventional example, vibration-damping materials are attached to all four sides around the vibration-transmitting plate, and the vibration sensor is separated from the vibration-damping material by a certain distance. The configuration in which the effective area where detection can be performed without lowering the accuracy is arranged at a position separated from the vibration sensor by a certain distance has a drawback that the entire device becomes larger than the effective area.

Further, in the case of the proposal of arranging the vibration sensor as in the conventional Japanese Patent Application No. 61-251599 on the boundary surface (upper side) of the change of the acoustic impedance, this mainly aims at the vibration sensor arrangement on the boundary surface of the side. However, the effect was limited to the vibration sensor adhesion side. Therefore, for example, when the vibration sensor is arranged at the boundary for mounting the vibration isolator (not shown), the device is enlarged by the width of the vibration isolator. Further, when the sensor is arranged on the end surface of the vibration transmitting plate (FIG. 15), the vibration sensor is not affected by the reflected wave with respect to the side where the vibration sensor is located. Although the device can be downsized by the width of the vibrating material, in principle, two or more vibration sensors are required for coordinate calculation by the coordinate input device, and the sides of other vibration transmission plates are required. In order to reduce the influence of reflected waves on the sensor arranged on the side surface of the vibration sensor, a vibration proof material must be attached to the side where the vibration sensor is located, as shown in FIG. Similarly, there is a drawback that the vibration damping material must be mounted, and the device becomes large by the width of the vibration damping material.

The present invention has been made in view of the above-mentioned conventional example, and provides a coordinate input device capable of preventing the coordinate detection accuracy from being deteriorated due to the influence of the reflected wave by the end face of the vibration transmitting plate and achieving the downsizing. The purpose is to do.

[0007]

In order to achieve the above object, a coordinate input device according to the present invention has the following configuration.

The vibration generating means, the vibration transmitting plate for transmitting the vibration generated by the vibration generating means, the plurality of vibration detecting means provided along the sides of the vibration transmitting plate, and the vibration in the vibration transmitting plate. Vibration reflection preventing means mounted along a side other than the side provided with the detecting means, measuring means for measuring a delay time of vibration detected by the vibration detecting means, and coordinate position based on the delay time. And a calculating means for calculating.

[0009]

【Example】

<Structure of Device> FIG. 1 shows the structure of the coordinate input device in this embodiment. In the figure, reference numeral 1 denotes an arithmetic control circuit for controlling the entire apparatus and calculating a coordinate position. Reference numeral 2 denotes a vibrator drive circuit for vibrating the pen tip inside the vibrating pen 3. Reference numeral 8 is a vibration transmission plate made of a transparent member such as acrylic or glass plate, and coordinates are input by the vibration pen 3 by touching the vibration transmission plate 8. That is, by designating the inside of the effective (input) area shown in the figure with the vibrating pen 3, the vibration generated by the vibrating pen 3 is incident on the vibration transmitting plate 8, and the incident vibration is measured and processed. The position coordinates of the vibrating pen 3 can be calculated.

As shown in FIG. 1, two vibration sensors 6a-6b for converting mechanical vibrations into electric signals, such as piezoelectric elements, are fixed to the four corners of the vibration transmitting plate. The vibrations propagated around the vibration transmission plate except the sides sandwiched by the two vibration sensors 6a and 6b are reflected by the end surface of the vibration transmission plate 8,
In order to prevent the multiple reflections from interfering with the direct wave from the vibrating pen 3 to the vibration sensor, the vibration isolator 7 is attached as shown in FIG. Regarding the side sandwiched by the two vibration sensors 6a and 6b, the reflected wave at the end face of the vibration transmission plate 8 on this side is not detected by the vibration sensor 6a and 6b because both are arranged on the reflection surface. Do not reach That is, there is no need to attach a vibration isolator because there is no influence of interference of reflected waves. Details regarding this configuration will be described later.

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. By driving the display drive circuit 10, it is 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).

The vibrator 4 built in the vibrating pen 3 is driven by the vibrator driving circuit 2. The drive signal of 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 vibration by the vibrator 4, and is 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 5, it is possible to perform efficient vibration conversion. 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, every 5 ms).
The oscillator drive circuit 2 outputs a signal for driving the oscillator 4 in the vibrating pen 3 and starts the time measurement by the internal timer (which is composed of a counter). Then, the vibration generated by the vibrating pen 3 arrives with a delay depending on the distance to the vibration sensors 6a to 6b.

The vibration waveform detection circuit 9 includes the vibration sensors 6a to 6a.
The signal from 6b is detected, and the signal indicating the vibration arrival timing to each vibration sensor is generated by the waveform detection processing described later. The arithmetic control circuit 1 inputs this signal for each sensor, and each vibration sensor The vibration arrival time of 6a to 6b is detected, and the coordinate position of the vibrating pen is calculated. 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 serial,
Coordinates are output to an external device by parallel communication (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, reference numeral 31 is a microcomputer for controlling the arithmetic control circuit 1 and the coordinate input device as a whole, and a non-volatile memory for storing an internal counter, a ROM storing operation procedures, and a RAM used for calculation and constants. It is composed of a memory and the like. Reference numeral 33 is a timer (not shown) that counts a reference clock (for example, is composed of a counter), and inputs a start signal to the vibrator driving circuit 2 to start driving the vibrator 4 in the vibration pen 3. Then, the timing starts. By this, the start of timing and the vibration detection by the sensor are synchronized, and the sensor (6a-
The delay time until the vibration is detected can be measured by 6b).

The circuits that are the respective components will be described in order.

The vibration arrival timing signals from the vibration sensors 6a-6b output from the signal waveform detection circuit 9 are latched through the detection signal input port 35 and latch circuits 34a-34.
Input to b. Each of the latch circuits 34a to 34b corresponds to each of the vibration sensors 6a to 6b, and when receiving the timing signal from the corresponding sensor, it latches the measured value of the timer 33 at that time. When the determination circuit 36 determines that all the detection signals have been received,
A signal to that effect is output to the microcomputer 31.
When the microcomputer 31 receives the signal from the determination circuit 36, the vibration arrival time from the latch circuits 34a to 34b to the respective vibration sensors is read from the latch circuit, a predetermined calculation is performed, and the vibration on the vibration transmission plate 8 is vibrated. The coordinate position of the pen 3 is calculated. Then, by outputting the calculated coordinate position information to the display drive circuit 10 via the I / O port 37, it is possible to display a dot or the like at a corresponding position on the display 11, for example. Alternatively, the coordinate value can be output to an external device by outputting the coordinate position information to the interface circuit via the I / O port 37.

<Explanation of vibration propagation time detection (FIGS. 4 and 5)
> Hereinafter, the principle of measuring the vibration arrival time to the vibration sensor 3 will be described.

FIG. 4 is a diagram for explaining a detection waveform input to the vibration waveform detection circuit 9 and a vibration transmission time measuring process based on the detection waveform. Although the case of the vibration sensor 6a will be described below, the same applies to the other vibration sensors 6b. It has already been described that the measurement of the vibration transmission time to the vibration sensor 6a is started at the same time when the start signal is output to the vibrator drive circuit 2. At this time, the drive signal 41 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 the signal 41 progresses for a time tg corresponding to the distance to the vibration sensor 6a, and then is detected by the vibration sensor 6a.

The signal indicated by 42 in the figure shows the signal waveform detected by the vibration sensor 6a. Since the vibration used in this embodiment is a plate wave, the envelope 421 and the phase 422 of the detected waveform with respect to the propagation distance in the vibration transmission plate 8
During vibration transmission, the relationship of changes according to the transmission distance. Here, the traveling speed of the envelope 421, that is, the group speed is Vg, and the phase speed of the phase 422 is Vp.
The distance between the vibration pen 3 and the vibration sensor 6a can be detected from the group velocity Vg and the phase velocity Vp.

First, focusing only on the envelope 421, its speed is Vg, and when a point on a certain specific waveform, for example, an inflection point or a peak such as a signal shown in FIG. 43 is detected, the vibration pen 3 and the vibration are detected. The distance between the sensors 6a is
Given that the vibration transmission time is tg, d = Vg · tg (1) This formula relates to one of the vibration sensors 6a, but the other three vibration sensors 6b are represented by the same formula.
The distance between 6d and the vibrating pen 3 can be similarly expressed.

Further, in order to determine the coordinates with higher accuracy, processing based on the detection of the phase signal is performed. The time from the specific detection point of the phase waveform signal 422, for example, the application of vibration to the zero cross point after a certain predetermined signal level 46 is tp.
45 (obtained by generating the window signal 44 having a predetermined width with respect to the signal 47 and comparing it with the phase signal 422), the distance between the vibration sensor and the vibration pen is d = n · λp + Vp · tp (2) Becomes 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
Is expressed as n = int [(Vg · tg−Vp · tp) / λp + 1 / N] (3).

Here, N is a real number other than "0", and an appropriate value is used. For example, if N = 2, then n can be determined if there is a variation such as tg within ± 1/2 wavelength. The distance between the vibration pen 3 and the vibration sensor 6a can be accurately measured by substituting the determined n into the equation (2). The signals 43 and 45 are generated by the vibration waveform detection circuit 9 for measuring the two vibration transmission times tg and tp described above, and the signal waveform detection circuit 9 is configured as shown in FIG.

FIG. 5 is a block diagram showing the configuration of the vibration waveform detection circuit 9 of the embodiment. In FIG. 5, the output signal of the vibration sensor 6a is amplified to a predetermined level by the preamplifier circuit 51. The bandpass filter 511 removes extra frequency components of the detected signal from the amplified signal,
For example, it is input to the envelope detection circuit 52 including an absolute value circuit and a low-pass filter, and only the envelope of the detection signal is extracted. The timing of the envelope peak is the envelope peak detection circuit 53.
Detected by. In the peak detection circuit, a signal tg (signal 43 in FIG. 4) which is an envelope delay time detection signal having a predetermined waveform is formed by the tg signal detection circuit 54 composed of a mono-multivibrator or the like, and is input to the arithmetic control circuit 1.

On the other hand, 55 is a signal detection circuit, which detects the envelope signal 42 detected by the envelope detection circuit 52.
The pulse signal 47 of the portion exceeding the threshold signal 46 of the predetermined level in 1 is formed. 56 is a monostable multivibrator, which opens the gate signal 44 of a predetermined time width triggered by the first rising edge of the pulse signal 47. Reference numeral 57 denotes a tp comparator, which detects the first rising zero-cross point of the phase signal 422 while the gate signal 44 is open, and supplies the phase delay time signal tp45 to the arithmetic control circuit 1. The circuit described above is the vibration sensor 6
The same circuit is provided for other vibration sensors.

<Explanation of delay time correction> Strictly speaking, the vibration transmission time latched by the latch circuit is, for example, the time during which the sound wave travels in the horn 5 or the time for processing the signal output from the sensor by the circuit. Contains. Therefore, these delay times other than the time when the wave propagates on the vibration transmission plate 8 are defined as the intrinsic delay time et. In addition, the difference between the group delay time and the phase delay time at the reference point is calculated as the phase offset time to
Define as ff. The error caused by these is always included in the same amount when the signal is transmitted from the vibration pen 3 to the vibration transmission plate 8 and the vibration sensors 6a to 6d. Therefore, for example, the position of the origin O in FIG. 6 is used as the above-mentioned reference point, the distance to the vibration sensor 6a is set to R1 (= X / 2), and the origin O measured by the vibration pen 3 at the origin O is measured. The measured vibration transmission time from the sensor to the sensor 6a is tgz ', tp
z ', the true transmission time from the origin O to the sensor and tg
Assuming z and tpz, these have a relationship of ttz '= tgz + et (4) tpz' = tpz + et + toff (5) with respect to the intrinsic delay time et and the phase offset toff.

On the other hand, the measured value t at an arbitrary input point P
Similarly, g ′ and tp ′ are tg ′ = tg + et (6) tp ′ = tp + et + toff (7). When the difference between (4), (6), (5) and (7) is calculated, tg'-tgz '= (tg + et)-(tgz + et) = tg-tgz (8) tp'-tpz Since '= (tp' + et + toff)-(tpz + et + toff) = tp-tpz (9), the circuit delay time et and the phase offset toff included in each transmission time are removed, and from the position of the origin O. It is possible to obtain the difference in the true transmission delay time according to the distance from the position of the sensor 6a between the input points P as the starting point.
The distance difference can be obtained by using the equation (3).

Since the distance from the vibration sensor 6a to the origin O is stored in advance in a non-volatile memory or the like and is known, the distance between the vibration pen 3 and the vibration sensor 6a can be determined. The other sensors 6b can be similarly obtained. The measured values tgz 'and tpz' at the origin O
Is stored in the non-volatile memory at the time of shipment, and the formulas (8) and (9) are executed before the calculation of the formulas (2) and (3), so that highly accurate measurement can be performed.

<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.

Now, if two vibration sensors 6a-6b are provided at the corners on the vibration transmission plate 8 at the positions S1 and S2, respectively, from the position P of the vibration pen 3 based on the principle described above. The linear distances da to db to the positions of the vibration sensors 6a to 6b can be obtained. 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 db by the following equation.

X = X / 2 + (da + db) · (da−db) / 2X (10) y = √ (da ² −x ² ) (11) where X is the position of the vibration sensors S1 and S2, respectively. It is the distance along the X-axis between the vibration sensor 6 and the sensor at the origin (position S1).

As described above, the position coordinates of the vibrating pen 3 can be detected in real time.

<Explanation Regarding Vibration Sensor / Vibration Isolator Structure>
Next, a description will be given of the vibration sensor arrangement and the vibration damping material mounting configuration in the coordinate input device of the present embodiment.

First, the arrangement of the vibration sensor will be described. In this embodiment, the vibration sensor 6 is arranged at the corner of the vibration transmission plate as shown in FIG. The vibration sensor may be fixed to the vibration transmitting plate by any means such as adhesion, crimping or any other means capable of detecting vibration from the vibration transmitting plate. by the way,
The corner of the vibration transmission plate where the vibration sensor is placed is
As shown in FIG. 7, for example, when focusing on the vibration sensor 6a, the vibration sensor 6a is located on the end face of the vibration transmission plate on two sides, side a and side b. In principle of vibration, the vibration sensor on the end surface of the vibration transmission plate, which is the reflected wave generation surface, detects only the direct wave from the vibration pen, and the reflected wave from the end surface of the vibration transmission plate where the vibration sensor is located. Will not be detected. Therefore, as shown in FIG. 7, for example, the vibration sensor 6a does not detect a reflected wave from the end faces of the vibration transmission plates on the sides a and b, that is, is not affected by the reflected wave. Similarly, the vibration sensor 6b has a side a and a side d.
The reflected wave from the end face of the vibration transmission plate is not detected, that is, the reflected wave is not affected.

On the contrary, it is obvious that the vibration sensor detects a reflected wave generated on the side of the end surface of the vibration transmission plate without the vibration sensor, and is adversely affected by the interference. Looking at this in FIG. 8, for example, the vibration sensor 6b detects the reflected waves from the end faces of the vibration transmission plates on the sides b and c, and is affected by the interference caused thereby. Similarly, the vibration sensor 6a has a side c and a side d.
The reflected wave from the end face of the vibration transmission plate of is detected and is affected by the interference.

As described above, in the structure in which the two vibration sensors are attached to the corners of the vibration transmission plate, the end surface of the common vibration transmission plate where the two vibration sensors are located, that is, the side sandwiched by the two vibration sensors. Is not affected by the reflected wave from the end face of the vibration transmission plate. Therefore, for example, as shown in FIG. 9, the side a sandwiched by the vibration sensors 6a and 6b can be a non-vibration material mounting area, and the other three sides are vibration damping material mounting areas.

As described above, the side sandwiched by the set of detection vibration sensors is set as the non-vibration material non-mounting area, and the vibration damping material is mounted on the other side to reduce the reflected wave over the entire input area. While preventing the accuracy from decreasing due to direct wave interference, it is possible to provide a non-vibration material non-mounting part (side),
Also, the size of the entire device can be reduced by the size between the vibration isolator and the vibration-sensor.

[0041]

[Other Embodiments] Next, as another embodiment, a case in which detection area division is combined with the above embodiment will be described.

In the structure in which the two vibration sensors are mounted on the corners of the vibration transmitting plate, as shown in FIG. 8, the vibration sensors 6a and 6b are separated from the side a sandwiched between them by three sides. Affected by the reflected waves of. For example, the vibration sensor 6b
In the case where an effective (input) area is provided on the entire surface of the vibration transmission plate as shown in the figure, a vibration damping material is attached to the side c in order to avoid the influence of the reflected wave from the side c. Figure 10
By setting the effective (input) area as an area away from the reflected wave generating side c, the direct wave vibration transmission path from the vibrating pen and the reflected wave vibration transmission path from the side c shown in the figure are detected. It can be set large so that the detection point of the waveform is not affected by interference. Therefore, the side c can be set as the non-vibration material mounting region. In this way, only the area near the two vibration sensors used for detection is set as an effective (input) area for the vibration sensor, and two sets are provided above and below (or left and right) of the vibration transmission plate to divide the detection area. This is another embodiment of the present invention shown in FIG. As shown in the figure, the (detection) area A includes the vibration sensors 6a and 6b.
And the vibration sensors 6c and 6d are in charge of the (detection) area B. In this structure, the sides a and c are the non-vibration material non-attachment regions. In other words, in this configuration, the side a sandwiched by the vibration sensors 6a and 6b can be a non-vibration material non-attachment region for the above reason, and at the same time, the reflected wave path can be sufficiently taken. By virtue of the fact that it is the side sandwiched between the vibration sensors 6c and 6d, the side c can also be a non-vibration material mounting region. The same applies to the vibration sensors 6c and 6d.

An explanatory view of the detection vibration sensor selection processing corresponding to the divided detection areas is shown in FIG. 12, and a flow chart of the detection vibration sensor selection processing is shown in FIG.

In FIG. 12, the position of the vibration input by the vibrating pen is P, and the positions of the vibration sensors 6a, 6b, 6c, 6d are a, b, c, d, and the coordinate calculation process is performed according to the procedure of FIG. explain.

First, when a vibration is input from the vibrating pen to the point P, the arithmetic control circuit 1 causes the distance p to each of the four sensors p.
Vibration delay times Ta to T corresponding to a, pb, pc, and pd
The data of b is fetched (S131).

Next, it is judged whether Ta + Tb ≧ Tc + Td with respect to the fetched four delay time data (S132). By this determination, it is determined whether the area having the coordinates input is the area A or the area B. Step S1
If the result of 32 is "YES", it means area B, and "N
If it is O ″, it is the area A.

Next, the input position P is calculated by using the data of the sensor corresponding to the determined area and by the coordinate calculation procedure described in the section <Description of coordinate position calculation> of the above-mentioned embodiment.
Is calculated (S133 or S134), and the coordinate calculation process ends. In addition to the above formula, the region determination formula may use a formula such as Ta ≧ Tc or Tb ≧ Td.

As described above, the region for detecting the position of the vibrating pen is divided, and a set of vibrating sensors in the vicinity of the divided region is selected as a detecting vibrating sensor for the detecting region. By setting the side sandwiched between the selected set of detection vibration sensors as the non-vibration material mounting area, the width of the vibration isolation material on the two sides of the vibration transmission plate and the dimension from the vibration isolation material to the vibration sensor Therefore, the size of the entire device can be reduced.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0050]

As described above, the coordinate input device of the present invention has an effect that the coordinate detection accuracy can be prevented from being lowered due to the influence of the reflected wave by the end face of the vibration transmitting plate, and the size can be reduced. .

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a coordinate input device.

FIG. 2 is a schematic explanatory diagram of a vibrating pen.

FIG. 3 is a block diagram showing a configuration of an arithmetic control circuit.

FIG. 4 is a timing chart of signal processing.

FIG. 5 is a block diagram showing a configuration of a signal waveform detection circuit.

FIG. 6 is an explanatory diagram for calculating coordinate positions.

FIG. 7 is an explanatory diagram related to an example of the present invention.

FIG. 8 is an explanatory diagram related to an example of the present invention.

FIG. 9 is an explanatory diagram related to an example of the present invention.

FIG. 10 is an explanatory diagram of another embodiment of the present invention.

FIG. 11 is an explanatory diagram relating to another embodiment of the present invention.

FIG. 12 is an explanatory diagram relating to another embodiment of the present invention.

FIG. 13 is an explanatory diagram relating to another embodiment of the present invention.

FIG. 14 is an explanatory diagram of a conventional example.

FIG. 15 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 1 arithmetic control circuit 2 oscillator drive circuit 3 vibrating pen 6 vibration sensor 7 anti-vibration material 8 vibration transmission plate 9 signal waveform detection circuit

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Hajime Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Katsuyuki Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Masaki Tokioka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. A vibration generating means, a vibration transmitting plate for transmitting the vibration generated by the vibration generating means, a plurality of vibration detecting means provided along the sides of the vibration transmitting plate, and the vibration transmitting plate. Vibration reflection preventing means mounted along a side other than the side where the vibration detecting means is provided, measuring means for measuring a delay time of vibration detected by the vibration detecting means, and coordinates based on the delay time. A coordinate input device comprising: a calculating unit that calculates a position. 2. The vibration transmitting plate has a rectangular shape, and the vibration detecting means is provided at both ends of one side of the vibration transmitting plate, and vibration reflection preventing means is attached to a side other than the one side. The coordinate input device according to claim 1. 3. A determination means for determining a region where vibration is generated based on the delay time, and a means for determining which vibration detection means to use based on the determination result by the determination means. The coordinate input device according to claim 1. 4. The vibration transmitting plate is rectangular, the pair of vibration detecting means is provided at both ends of the opposite two sides, and the vibration reflection preventing means is mounted on the two sides sandwiched by the pair of vibration detecting means. The coordinate input device according to claim 3, wherein: