JPH0981296A - Coordinate input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coordinate input device having excellent operability and high accuracy in respect to a coordinate input device for inputting coordinates by giving vibration to a vibration transmission board. SOLUTION: When the pen tip 5 of a vibration input pen 3 is touched with the vibration transmission board 8 to input coordinates, a sheet-like piezoelectric element 12 converts the vibration into an electric signal and outputs the electric signal to a signal waveform detecting circuit 9. The circuit 9 detects the input timing of the vibration from the output of the element 12. The inputted vibration is transmitted through the board 8 and reached to vibration sensors 6a to 6d. The sensors 6a to 6d respectively convert the arriving vibration into electric signals and respectively output the signals to the circuit 9. The circuit 9 detects the timing of the arriving vibration based upon the outputs of the sensors 6a to 6d. An arithmetic and control unit 1 calculates distances from the input position of the vibration up to respective sensors 6a to 6d based upon timing differences (transmission time) and finds out the input coordinates of the vibration.

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 applying a vibration on a vibration transmission plate to input coordinates.

[0002]

2. Description of the Related Art A coordinate input device utilizing ultrasonic vibration is
For example, as disclosed in Japanese Patent Publication No. 5-60615, the time from the timing when the vibration input pen starts driving to the time when the sensor on the vibration transmission plate detects it is measured, and the measured time and vibration are measured. The distance from the input point of the vibration input pen to the sensor is converted by multiplying the sound velocity of ultrasonic vibration transmitted through the transmission plate, and the coordinates are calculated by a predetermined coordinate calculation formula.

Therefore, in order to make the vibration input pen a cordless type in which the main body including the vibration transmission plate is not connected by a cord, the drive start timing of the vibration input pen is notified to the main body side by some method. Alternatively, a method that does not require drive start timing is required.

<Prior Art Example 1> Conventionally, there has been provided a wireless communication means such as infrared rays on the vibration input pen side in order to inform the main body side of the driving timing of the vibration input pen.

<Prior Art 2> Further, as a structure effective for cost reduction or power consumption reduction, a technique is proposed in which a vibration input pen is a cordless type, but a drive start timing is not required as described below. ing.

In this method, the vibration input from the vibration input pen is detected by a plurality of sensors on the input plate, and one of the plurality of sensors (for example, the vibration from the input point comes first). The arrival delay time of the vibration at the sensor (arriving sensor) is used as a reference, and the coordinate of the vibration input pen on the input plate is determined by the difference data between the reference arrival delay time and the arrival delay time of the vibration at other sensors. Is.

In the coordinate calculation method of the above method, the coordinate input surface is divided into a plurality of areas and the coordinates are calculated for each area in order to improve the accuracy of the coordinate calculation. FIG. 8 is a diagram for explaining the coordinate calculation method of the conventional example. In the figure, 7
1a to 71d are vibration sensors, and P (x, y) is the coordinates at which the vibration input pen contacts the vibration transmission plate. Also, da is 7
1a is the distance between P (x, y), and db is 71b and P (x, y).
y), dc is the distance between 71c and P (x, y),
dd is the distance between 71d and P (x, y).

With reference to the vibration sensor 71a as shown in the figure, the difference data Δdb, Δdc, Δdd at the positions of the vibration sensors 71b to 71d are Δdb = db-da (Equation (1) Δdc = dc-da ... Formula (2) Δdd = dd-da Formula (3) The coordinates P (x, y) to be obtained from the difference data of Expressions (1) to (3) are as follows.

When Δdd + Δdb−Δdc ≠ 0, the area 2 or the area 3, that is, Δdb> 0, and Δd
c> 0 and Δdb> Δdd, or Δdb <0,
When Δdc <0 and Δdb <Δdd, the coordinate P (x, y) of the vibration input pen is x = X / 2−Δdd ^ 2 / 2X + Δdd · (Δdb ^ 2 + Δdd ^ 2−Δdc ^ 2)] /[X·(Δdd+Δdb−Δdc)]...Equation (4) y = Y / 2−Δdb / {2 · [4x ^ 2 / (Y ^ 2-Δdb ^ 2) +1] ^ (1/2) } It is Formula (5). Here, x in Expression (5) is a value obtained by Expression (4). Note that A ^ B represents A raised to the Bth power.

Further, the area 1 or the area 3, that is,
Δdd> 0 and Δdc> 0 and Δdb <Δdd, or Δdd <0 and Δdc <0 and Δdb> Δ
When it is dd, the coordinate P (x, y) of the vibration input pen is y = Y / 2-Δdb ^ 2 / 2Y + [Δdb · (Δdb ^ 2 + Δdd ^ 2-Δdc ^ 2)] / [Y · ( [Delta] dd + [Delta] db- [Delta] dc)] Equation (6) x = X / 2- [Delta] dd / {2 * [4y ^ 2 / (X ^ 2- [Delta] dd ^ 2) +1] ^ (1/2)} Equation (7) Here, y in Expression (7) is a value obtained by Expression (6).

When [Delta] dd + [Delta] db- [Delta] dc = 0, ie, x = X / 2, [Delta] dd = 0 (da = dd, dd).
= Dc), or y = Y / 2 and Δdb = 0 (d
When a = db, dc = dd), the coordinate P (x, y) of the vibration input pen is y = (Y ± [Δdb ^ 2 · (1 + X ^ 2 / (Y ^ 2-Δdb ^ 2))) ] ^ (1/2)) / 2 Formula (8) x = (X ± [Δdd ^ 2 · (1 + Y ^ 2 / (X ^ 2-Δdd ^ 2))] ^ (1/2)) / 2 ... Expression (9).

With the above method, the coordinates at which the vibration input pen contacts the vibration transmission plate can be obtained and the coordinates can be input.

[0013]

However, providing the wireless communication means such as infrared rays on the vibration input pen side as in the above-mentioned conventional example 1 causes an increase in the circuit scale and drives those circuits. There was a problem that it needed power for.

In the case of the above-mentioned conventional example 2, equations (1) to
When each difference data (Δdb, Δdc, Δdd) in (3) becomes a value close to zero, the error of each difference data is magnified by the equations (4) and (6). According to this
The calculation results of the equations (5) and (7) naturally include a large error.

Further, in the vicinity of the center, the error of each difference data greatly affects the area determination (which area it belongs to), and it is determined that the area is different from the area actually touched by the vibration input pen, and the coordinates are calculated. Therefore, it is not possible to accurately recognize the coordinates with which the vibration input pen contacts.

The present invention has been made in view of the above problems, and provides a coordinate input device which is excellent in operability and has high accuracy in a coordinate input device which applies a vibration to a vibration transmission plate to input coordinates. The task is to do.

[0017]

In order to solve the above-mentioned problems, a coordinate input device according to the present invention is a coordinate input device for applying a vibration to a vibration transmission plate to input coordinates. A vibration input means for inputting vibration on the plate; an input vibration detecting means for detecting the input of the vibration; and a plurality of transfer vibration detecting means for detecting the vibration transmitted from the vibration transmitting plate from the input position of the vibration, It is characterized by further comprising input position calculation means for calculating an input position of the vibration from a time difference between the detection of the vibration by the input vibration detection means and the detection of the vibration by the transmission vibration detection means.

According to a preferred embodiment of the present invention, for example, the input vibration detection means has a sheet-shaped piezoelectric body arranged on the vibration transmission plate, and the input of vibration is detected by the sheet-shaped piezoelectric body. It may be configured to.

Further, for example, the plurality of transmission vibration detecting means may each have a vibration sensor arranged at an end portion of the vibration transmission plate, and the vibration transmitted by the vibration sensor may be detected.

Further, for example, the vibration sensors may be arranged at four corners of the vibration transmission plate.

Further, for example, the sheet-shaped piezoelectric body and the vibration transmission plate may be made of a transparent material.

Further, for example, display means for displaying an image may be further provided behind the vibration transmission plate.

Further, for example, the display means may display the calculated input position of the vibration.

Further, for example, the sheet-shaped piezoelectric body and the vibration sensor may be arranged on the vibration transmission side of the vibration transmission plate.

Further, for example, the sheet-shaped piezoelectric body and the vibration sensor may be arranged on the back surface of the vibration transmission plate on the side for inputting vibration.

Further, for example, the vibration input means may be a cordless type vibration input pen.

Another coordinate input device according to the present invention is
A coordinate input device for applying a vibration to a vibration transmitting plate to input coordinates, wherein input vibration detecting means for detecting the input vibration and vibration transmitted from the vibration transmitting plate from an input position of the vibration are detected. A plurality of transmission vibration detecting means, and an input position calculating means for calculating an input position of the vibration from a time difference from the detection of the vibration by the input vibration detecting means to the detection of the vibration by the transmission vibration detecting means. Characterize.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment of the Invention> FIG. 1 is a diagram showing an example of an embodiment of a coordinate input device according to the present invention. In the figure, 1
Is an arithmetic control circuit that controls the entire apparatus and calculates coordinate values. Reference numeral 8 is a vibration transmission plate made of a transparent member such as acrylic or glass plate, and ITO is attached as an electrode on both surfaces of a piezoelectric material such as PVDF (polyvinylidene fluoride) by vapor deposition or sputtering on its upper surface. The sheet-shaped piezoelectric bodies 12 are laminated and arranged. The coordinate input by the vibration input pen 3 is performed by touching the vibration transmission plate 8. 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, and mechanical vibration is provided at the boundary by a piezoelectric element such as PZT. Vibration sensors 6a to 6d for converting into electric signals are fixed.

Reference numeral 9 is 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 8. By driving the display drive circuit 10, the display 9 displays dots at the positions traced by the vibration input pen 3. As described above, since the vibration transmission plate 8 is made of a transparent material, the display 9
The image displayed above is transparent.

The vibrator 4 built in the vibration input pen 3 is
It is driven by the oscillator drive circuit 2. The electric drive signal is converted into mechanical ultrasonic vibration by the vibrator 4,
It is transmitted to the vibration transmission plate 8 via the pen tip 5.

Here, the vibration frequency of the vibrator 4 is selected so that a plate wave can be generated in the vibration transmission plate 8 such as glass. When the vibrator 4 is driven, the vibration transmission plate 8
A mode that oscillates in the vertical direction is selected. Further, by setting the vibration frequency of the vibrator 4 to be the resonance frequency including the pen tip 5, an efficient vibration variable is possible.

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 with surface waves. .

In the above configuration, the oscillator drive circuit 2
Outputs a signal for driving the vibrator 4 every predetermined period.
The vibration generated by the vibration input pen 3 is first detected by the sheet-shaped piezoelectric body 12, and then delayed according to the distance from the position of the vibration input pen 3 to each of the vibration sensors 6a to 6d. Reach ~ 6d.

The vibration waveform detection circuit 9 is composed of the sheet piezoelectric body 1.
2 and the signals from the vibration sensors 6a to 6d are detected,
Each of the vibration sensors 6a to 6d is processed by a waveform detection process described later.
The timing signals (signals Tg and Tp) indicating the respective vibration arrival timings are generated and supplied to the arithmetic control circuit 1. The arithmetic and control circuit 1 obtains the vibration transmission time from the vibration input pen 3 to each of the vibration sensors 6a to 6d according to the timing signal supplied to each of the vibration sensors 6a to 6d, and determines the coordinate position of the vibration input pen 3. calculate.

The arithmetic control circuit 1 also performs various arithmetic operations based on the calculated position information of the vibration input pen 3 to drive the display drive circuit 10 to control the display on the display 11 or to perform serial communication. Means or parallel communication means (not shown) to output the coordinate information to the external device.

FIG. 2 is a diagram showing a detailed configuration of the signal detection circuit 9. The output signal of the sheet-shaped piezoelectric body 12 is input to the sheet-shaped piezoelectric body waveform detection circuit 210, and is amplified to a predetermined level by the preamplification circuit 21. The bandpass filter 211 removes excess frequency components of the detected signal from the amplified signal, the input signal detection circuit 22 forms a pulse signal, and the pulse signal is supplied to the arithmetic control circuit 1.

The output signals of the vibration sensor 6 (6a-6d) are input to the vibration sensor waveform detection circuit 220.
In the drawings, the vibration sensor waveform detection circuit 220
Although only one is shown, each vibration sensor 6a ...
There are four corresponding to 6d. First, the output signal of the vibration sensor 6 is amplified by the preamplifier circuit 23 to a predetermined level. The amplified signal is input to the envelope detection circuit 24 including, for example, an absolute value circuit and a low pass filter, and only the envelope of the detection signal is extracted. The extracted envelope signal is differentiated by the twice differentiating circuit 25. Tg signal detection circuit 26
Is composed of a mono multivibrator etc., for example,
A signal Tg which is a delay time detection signal is formed by detecting a zero-cross point after the envelope exceeds a predetermined level, and is supplied to the arithmetic control circuit 1.

Further, the band-pass filter 231 removes the excess frequency component of the detection signal from the signal amplified by the preamplifier circuit 23 to a predetermined level. Reference numeral 27 denotes a Tp signal detection circuit which is composed of a comparator and the like and forms a pulse signal of a portion where the output signal of the bandpass filter 231 exceeds a threshold value of a predetermined level.

FIG. 3 is a diagram showing a detailed configuration of the arithmetic control circuit 1. In the figure, reference numeral 31 is a microcomputer for controlling the arithmetic control circuit 1 and the coordinate input device as a whole, a ROM storing the following control procedure, a RAM used as a work memory for performing arithmetic operations, and a reference for controlling. It is composed of a non-volatile memory or the like for storing constants and the like.

Reference numerals 32a to 32d are counters, which start timing by using an output signal of the start signal detecting section 210 (that is, a signal obtained by processing the output signal of the sheet-shaped piezoelectric body 12) as a start signal (a signal START described later), The period until the output signal of the vibration sensor waveform detection circuit 220 (the signals Tg and Tp obtained by processing the output signals of the vibration sensors 6a to 6d respectively) changes is measured. This allows the vibration input pen 3
After inputting the vibration, it is possible to measure each transmission time required for the vibration to be transmitted from the vibration transmission plate 8 to the vibration sensors 6a to 6d.

The determination circuit 34 determines the vibration sensor 6a based on the output signals (Tg and Tp) of the transmission signal detector 220.
It is determined that .about.6d has detected the vibration by the vibration input pen 3. When the determination result indicating that the vibration is detected is input to the microcomputer 31, the counters 32a to 32d are input.
Among them, the corresponding count value (clocking time) is referred to obtain the vibration transmission time (tg and tp described later) for each of the vibration sensors 6a to 6d, and based on this, the coordinates of the vibration input pen 3 on the vibration transmission plate 8 are obtained. To calculate. The calculated coordinates are
For example, dots can be displayed at corresponding positions on the display 11 via the I / O port 36.
Further, it can be supplied to an external device by supplying it to an interface circuit (not shown) through the I / O port 36.

FIG. 6 is a flow chart for explaining the flow of the operation of the microcomputer 31, and the ROM (not shown) provided inside the microcomputer 31 stores the program instruction sequence corresponding to this flow chart. First, in step S601, the counters 32a to 32d, the detection signal input circuit 35, the I / O port 36, etc. are reset. In step S602, the vibration transmission time from the vibration input pen 3 to the vibration sensors 6a to 6d is measured. In step S603, the distance between the vibration input pen and each of the vibration sensors 6a to 6d is calculated. In step S604, the coordinates of the vibration input pen 3 are calculated. Then, in step S605, based on the calculated coordinates, dots are displayed at corresponding positions on the display 11 as described above. Hereinafter, specific examples of steps S602 to S604 will be described in detail.

<Measurement example of vibration transmission time (step S60)
2)> Next, the vibration transmission time on the vibration transmission plate 8, that is, the time from when the sheet piezoelectric body 12 detects the input of the vibration by the vibration input pen 3 until the vibration sensors 6a to 6d detect the vibration. The principle of measuring is explained.

FIG. 4 is a diagram for explaining the detection waveform supplied from the sheet-shaped piezoelectric body 12 to the vibration waveform detection circuit 9 and the processing for measuring the vibration transmission time based on the detection waveform. The vibrator 4 is driven by the vibrator driving circuit 2 at a predetermined cycle, and the pen tip 5 of the vibration input pen 3 comes into contact with the sheet piezoelectric body 12 arranged on the vibration transmission plate 8 to obtain the sheet piezoelectric body. Reference numeral 12 detects vibration and converts it into an electrical signal. The output signal of the sheet-shaped piezoelectric body 12 is, as described above, the preamplifier circuit 2
Amplified by 1. The signal 40 is the output signal of the preamplifier circuit 21. The signal 40 is supplied to the input signal detection circuit 22 after the excess frequency component is removed by the bandpass filter 211, and is converted into the pulsed signal 41 by the input signal detection circuit 23. The signal START is an output signal of the input signal detection circuit. The counter 32 described above
The a to 32d start the counting operation at the first rising edge of the signal START.

Next, the flow of detection of vibration related to the vibration sensors 6a to 6d will be described by taking the vibration sensor 6a as an example (6b to 6d are the same as 6a). As described above, the measurement of the vibration transmission time of the vibration to the vibration sensor 6a is performed by the signal ST.
It starts with the rising edge of ART. Vibration input pen 3
The ultrasonic vibration given by is delayed by the time corresponding to the distance to the vibration sensor 6a and detected by the vibration sensor 6a. The signal 42 indicates an output waveform obtained by amplifying the output of the vibration sensor 6a by the preamplifier 23. The signal 42 (phase signal) is supplied to the envelope detection circuit 24, and the envelope signal 421 is taken out. The extracted envelope signal 421 is differentiated by the twice differentiating circuit 25, and its output has a waveform like the signal 43.
The Tg signal detection circuit 26 is composed of a mono multivibrator or the like. Then, the window signal 48 that gives a fixed period after the envelope signal 421 exceeds the predetermined level is generated to mask the signal 43, and the envelope signal 421 is generated.
After the voltage exceeds a predetermined level, the zero cross point of the signal 43 is detected, and a signal Tg which is a delay time detection signal is generated.
Here, the time from the rising of the signal START to the rising of the Tg signal is tg.

The band pass filter 231 removes the extra frequency component of the signal 42 which is a phase signal and outputs the signal 44. The Tp signal detection circuit 27 includes the band pass filter 2
The pulse signal 45 of the portion where the output signal 44 of 31 exceeds the threshold value 441 of the predetermined level is generated, and the window signal 46 having a predetermined width is generated with the first pulse as a starting point. Then, the signal 44 is masked by the window signal 46 and pulse-converted to generate the signal Tp. Signal ST
The time from the rise of ART to the rise of Tp signal is tp.

<Example of Calculation of Distance between Vibration Input Pen and Vibration Sensor (Step S603)> The phase relationship changes during vibration transmission according to the transmission distance. Here, the traveling speed of the envelope (signal 421), that is, the group speed is Vg,
Let Vp be the speed at which the phase (signal 422) advances, that is, the phase speed. From the group velocity Vg and the phase velocity Vp, the vibration pen 3
The distance between the vibration sensor 6a and the vibration sensor 6a can be detected.

First, pay attention to the envelope (signal 421). When the velocity of the envelope is Vg and the vibration transmission time is tg, the vibration input pen 3 and the vibration sensor 6a.
The approximate distance d ′ to each of the 6d is given by d ′ = Vg · tg (Equation (10)). With this formula (10), the vibration input pen 3
It is possible to calculate the approximate distance between each of the vibration sensors 6a to 6d.

Further, when the transmission time tp of the phase (signal 422) is used for more accurate coordinate determination, the distance d between the vibration input pen 3 and each of the vibration sensors 6a to 6d is d = nλp + Vp -Tp: It is given by Formula (11). Here, λp is the wavelength of the elastic wave, and n is an integer.

From equations (10) and (11), the above integer n
Is expressed by the following formula: n = [(Vg · tg−Vp · tp) / λp + 1 / N] Equation (12).

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 value of n obtained from equation (12) is given by equation (11)
To the vibration input pen 3 and the vibration sensor 6a by using the discontinuous but highly accurate transmission time tp.
The distance to each of ~ 6d can be accurately measured.

<Example of Calculation of Coordinates (Step S604)> FIG. 5 is a diagram for explaining an example of calculation of coordinate positions. Four vibration sensors 6a are provided on the vibration transmission plate 8 near the vertices of the four sides.
If 6d are provided at the positions Sa to Sd, the position P (x, y) of the vibration input pen 3 is based on the principle described above.
To the positions of the respective vibration sensors 6a to 6d can be calculated using the equations (11) and (12).

Further, the arithmetic control circuit 1 calculates the coordinate P of the vibration input pen 3 based on the linear distances da to dd.
(X, y) can be obtained from the Pythagorean theorem as follows.

X = X / 2 + (da + db) · (da−db) / 2X (Equation (13)) y = Y / 2 + (da + dd) · (da−dd) / 2Y (Equation (14)) Here, X is the distance between the vibration sensors 6a and 6b, and Y is the distance between the vibration sensors 6a and 6d.

In the above structure, the sheet-shaped piezoelectric body is arranged on the upper surface of the vibration transmitting plate, but the invention can be realized by using the same vibration detecting method even if it is arranged on the lower surface.

According to the above configuration, the coordinates designated by the vibration input pen can be accurately calculated in real time without increasing the circuit scale of the cordless vibration input pen.

[Second Embodiment of the Invention] In the above-described first embodiment, the first sensor for detecting the input timing by the vibration input pen is a sheet-shaped piezoelectric body, and a plate for propagating the vibration transmission plate. The second sensor for detecting the wave is a piezoelectric element. The embodiment described here describes a case where the two types of sensors on the vibration transmission plate are composed of only sheet-shaped piezoelectric bodies. The configuration other than the detection means is
It is assumed that the configuration is similar to that of the first embodiment.

FIG. 7 is a diagram showing a schematic configuration of the coordinate input section in this embodiment. In the figure, 61a to 61
d and 62 are sheet-shaped piezoelectric bodies, and after the sheet-shaped piezoelectric body 62 detects the input timing by the vibration input pen 3, a plate wave propagating through the vibration transmission plate 63 is generated.
It is detected by 1a to 61d.

The sheet-shaped piezoelectric body can be positioned with high precision in a predetermined size and shape by etching or the like after being attached or pressed onto the entire surface of the vibration transmitting plate. .

In this embodiment as well, even if the sheet-shaped piezoelectric body is formed on the lower surface of the vibration transmitting plate, it is possible to detect vibration as in the first embodiment.

According to the above configuration, the coordinates of the cordless vibration input pen can be calculated with high accuracy, and a thin coordinate input device can be constructed.

[Third Embodiment of the Invention] In the first and second embodiments, the vibration transmitting plate, the sheet-shaped piezoelectric material, and the electrodes located on the display screen are made of a transparent material. However, an opaque material may be used as the constituent material when it is not necessary to configure the display apparatus such as a liquid crystal display integrally with the display apparatus. For example, the present application can be realized by using piezoelectric ceramics for the sheet-shaped piezoelectric body and aluminum or the like for the electrodes and the vibration transmission plate.

The present invention may be applied to a system composed of a plurality of devices or a single device. Further, it goes without saying that the present invention can be applied to the case where it is implemented by supplying a program to a system or an apparatus. In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program from the storage medium to the system or device, the system or device
It works in a predetermined way.

[0065]

As described above, according to the present invention, in a coordinate input device for applying a vibration to a vibration transmitting plate to input coordinates, the means for inputting the vibration to the vibration transmitting plate is mechanically coupled to the main body, The structure can be electrically separated, the means for inputting vibration can be downsized, and the operability can be improved.

Further, by providing the means for detecting the input of vibration on the vibration transmission plate to obtain the transmission time of the vibration, the coordinates at which the vibration is input can be accurately calculated.

[0067]

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an embodiment of a coordinate input device according to the present invention.

FIG. 2 is a diagram showing a detailed configuration of a signal detection circuit.

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

FIG. 4 is a diagram illustrating a detection waveform supplied from a sheet-shaped piezoelectric body to a vibration waveform detection circuit and a vibration transmission time measurement process based on the detection waveform.

FIG. 5 is a diagram for explaining an example of calculating coordinate positions.

FIG. 6 is a block diagram illustrating a flow of operation of a microcomputer.

FIG. 7 is a diagram showing a schematic configuration of a coordinate input unit in the second embodiment.

FIG. 8 is a diagram for explaining a coordinate calculation method of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arithmetic control circuit 2 Oscillator drive circuit 3 Vibration input pen 4 Oscillator 5 Pen tip 6a-6d Vibration sensor 7 Anti-vibration material 8 Vibration transmission plate 9 Signal waveform detection circuit 10 Display drive circuit 11 Display 12 Sheet piezoelectric body 61a- 61d Vibration sensor 62 Sheet-shaped piezoelectric body 63 Vibration transmission plate 71a-71d Vibration sensor

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yuichiro Yoshimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Atsushi Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Ryozo Yanagisawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. A coordinate input device for applying a vibration to a vibration transmitting plate to input coordinates, wherein a vibration input means for inputting a vibration on the vibration transmitting plate and an input vibration detecting means for detecting an input of the vibration. A plurality of transmission vibration detecting means for detecting the vibration transmitted from the vibration transmission plate from the input position of the vibration, and a time difference from the detection of the vibration by the input vibration detecting means to the detection of the vibration by the transmission vibration detecting means. An input position calculating means for calculating the input position of the vibration, and a coordinate input device. 2. The input vibration detection means has a sheet-shaped piezoelectric body arranged on the vibration transmission plate, and the vibration input is detected by the sheet-shaped piezoelectric body. Coordinate input device. 3. The plurality of transmitted vibration detecting means each have a vibration sensor arranged at an end portion of the vibration transmission plate, and detect the vibration transmitted by the vibration sensor. The coordinate input device according to claim 1 or claim 2. 4. The coordinate input device according to claim 3, wherein the vibration sensor is arranged at each of four corners of the vibration transmission plate. 5. The coordinate input device according to claim 1, wherein the sheet-shaped piezoelectric body and the vibration transmission plate are made of a transparent material. 6. The coordinate input device according to claim 5, further comprising display means for displaying an image behind the vibration transmission plate. 7. The coordinate input device according to claim 6, wherein the display means displays the calculated input position of the vibration. 8. The sheet-shaped piezoelectric body and the vibration sensor are arranged on the vibration input side of the vibration transmission plate, as claimed in any one of claims 1 to 7. Coordinate input device. 9. The sheet-shaped piezoelectric body and the vibration sensor are arranged on the back surface of the vibration transmission plate on the side where vibration is input, according to any one of claims 1 to 7. The coordinate input device described in. 10. The coordinate input device according to claim 1, wherein the vibration input means is a cordless vibration input pen. 11. A coordinate input device for applying a vibration to a vibration transmitting plate to input coordinates, comprising: input vibration detecting means for detecting the input vibration; and transmitting the vibration transmitting plate from an input position of the vibration. A plurality of transmission vibration detection means for detecting incoming vibrations, and an input position calculation means for calculating an input position of the vibration from a time difference between the detection of the vibration by the input vibration detection means and the detection of the vibration by the transmission vibration detection means. A coordinate input device comprising: