JPH10307669A - Coordinate input device and input method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable and excellent input feeling irrelevantly to the input state of a vibration input position, pen stroke pressure, etc., by driving a vibration source at driving level lower than 1st driving level and generating a signal for coordinate detection according to a vibration detection signal when the vibration detection signal exceeds a threshold value. SOLUTION: It is decided whether or not the detection signal of a vibration detecting means exceeds the threshold value and when it is decided that the threshold value is exceeded, the vibration source is driven at the 2nd driving level lower than the 1st driving level to generate the signal for coordinate detection according to the detection signal from the vibration detecting means. Namely, this device inputs an envelope signal at its level decision circuit 40. Here, the decision threshold value is set and whether or not the input signal exceeds a specific level is detected. The decision result of the level decision circuit 40 is inputted as a decision signal to an arithmetic control circuit 1. The arithmetic control circuit 1 switches the driving level of a pen 3 according to the decision result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coordinate input device and a control method therefor. In particular, a coordinate input device that detects elastic wave vibration input from a vibration pen with a plurality of sensors provided on a vibration transmission plate, and detects coordinates of the vibration input point based on a transmission time of the elastic wave vibration, and a control thereof. It is about the method.

[0002]

2. Description of the Related Art An ultrasonic coordinate input device is disclosed in
As disclosed in -62771, this is a method of detecting a delay time of a wave propagating on a tablet as an input surface and calculating position coordinates. According to this kind of coordinate input device, it is not necessary to work a matrix-shaped electric wire or the like on the tablet, so that it is possible to provide an inexpensive device. In addition, if a transparent plate glass is used for the tablet, a coordinate input device having higher transparency than other coordinate detection methods can be configured.

In a general configuration of a coordinate input device using ultrasonic waves, a vibration sensor for converting mechanical vibration into an electric signal, such as a plurality of piezoelectric elements, is fixed on a vibration transmission plate, and a vibration pen is used when the vibration is generated. , The time until the vibration is detected by each vibration sensor is measured, and the vibration input position is calculated based on the measurement result.

[0004]

The signal detected by the vibration sensor is weak and is not suitable for performing signal processing as it is. Therefore, it is general to amplify the signal using a preamplifier. is there. Usually, the gain of the preamplifier is set such that the maximum value of the detection signal falls within the power supply voltage of the processing circuit.

[0005] In such a coordinate input device using elastic waves, the detection signal level varies greatly due to the vibration transmission distance, pen pressure, pen angle, and component variations. Usually, the threshold value for signal detection is determined in consideration of the variation width due to these factors, the electromagnetic noise level, and the power supply voltage.

However, in the case of a coordinate input device using a plate wave A0 wave, an S0 wave, which is unnecessary vibration, is generated, and the minimum detection level (detection threshold) of A0 wave detection is limited by the highest level of the unnecessary vibration. Will be.

[0007] The level of the S0 wave is generally 3% to 3% of the A0 wave.
This is about 9%, which is much larger than a normal electromagnetic noise level. However, if the detection threshold is set so as not to detect the S0 wave, the effective signal amplitude range of the A0 wave, which is the vibration to be detected, becomes very narrow. For this reason, there is a case where it is difficult for the A0 wave to exceed the detection threshold due to the above-mentioned fluctuation factors (vibration transmission distance, pen pressure, pen angle, etc.), and there is a problem that input is difficult and input feeling is deteriorated. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a coordinate input apparatus and a control method thereof capable of obtaining a stable and good input feeling irrespective of input states such as a vibration input position, a pen pressure, and a pen angle. The purpose is to provide.

[0009]

A coordinate input apparatus according to the present invention for achieving the above object has the following arrangement.
That is, a coordinate input device that acquires an input position of a vibration based on a delay time until a vibration input from a vibration source to a vibration transmission plate reaches a vibration detection unit, wherein the vibration source is a first input device. A first driving unit that drives at a drive level and generates a signal for coordinate detection based on a detection signal from the vibration detection unit; and whether a detection signal detected by the vibration detection unit exceeds a first threshold value Determining means for determining whether the vibration source has exceeded the first threshold; and setting the vibration source to a second drive level lower than the first drive level.
And a second drive means for driving at the drive level of, and generating a signal for coordinate detection based on a detection signal from the vibration detection means.

A method for controlling a coordinate input device according to the present invention for achieving the above object includes the following steps. That is, a method of controlling a coordinate input device that acquires an input position of a vibration based on a delay time until a vibration input from a vibration source to a vibration transmission plate reaches a vibration detection unit, wherein the vibration source is Drive at a first drive level,
A first driving step of generating a signal for coordinate detection based on a detection signal from the vibration detecting means, and a determining step of determining whether a detection signal detected by the vibration detecting means has exceeded a first threshold value; When it is determined that the detection signal exceeds the first threshold, the vibration source is driven at a second drive level lower than the first drive level, and based on the detection signal from the vibration detection means. And a second driving step of generating a signal for coordinate detection.

[0011]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of the coordinate input device according to the present embodiment. In the figure, reference numeral 1 denotes an arithmetic control circuit for controlling the entire apparatus and calculating a coordinate position. 2
Is a vibrator driving circuit, which is stored in the vibrating pen 3;
A vibrator (piezoelectric element such as PZT) 4 in the pen 3 is driven by a pen drive signal output from the arithmetic control circuit 1. The vibration generated by the vibrator 4 passes through the horn and causes the pen tip 5 to vibrate. Reference numeral 8 denotes a vibration transmission plate made of a transparent member such as a glass plate. Coordinate input by the vibration pen 3 is performed by touching the vibration transmission plate 8. Actually, coordinate input is performed by designating the area within the area indicated by the symbol A (hereinafter referred to as an effective area) indicated by a solid line with the vibration pen 3.

A vibration isolator 7 is provided on the outer periphery of the vibration transmission plate 8 to prevent (reduce) the reflected vibration from returning to the central portion. The vibration sensors 6a to 6d for converting into signals are fixed.

The vibrations detected by the sensors 6a to 6d are amplified by the preamplifiers 12a to 12d and are amplified by the signal waveform detection circuit 9.
Is input to Reference numeral 11 denotes a display such as a liquid crystal display, which is arranged behind the vibration transmission plate. The arithmetic control circuit outputs the coordinate values specified by the vibrating pen 3 to a host device (not shown) such as a personal computer, and the host device drives the display drive circuit 10 based on the coordinates, and the host device outputs the coordinates as if the pen were printed on paper. It is possible to perform display as written with.

The vibration frequency of the vibrator 4 is selected to a value at which a plate wave can be generated on the vibration transmission plate 8. Therefore, the elastic wave propagating through the vibration transmission plate 8 is a plate wave, and has an advantage that the surface of the vibration transmission plate is less susceptible to scratches, obstacles, and the like than surface waves.

The arithmetic and control circuit 1 operates at predetermined intervals (for example, 10
Every millisecond), the coordinate acquisition operation is repeated to output the coordinates.
In the coordinate acquisition operation, a plurality of sensors are sequentially selected,
The arrival delay time of the elastic wave is detected for each sensor. The arrival delay time is a group delay time tg based on the group velocity of the plate wave.
And a phase delay time tp based on the phase speed. Based on the two delay times, the distance between the input pen and each sensor is calculated.

FIG. 2 is a block diagram showing the configuration of the signal waveform detection circuit 9. FIG. 3 is a diagram for explaining signal processing in the present embodiment.

In the delay time measurement, first, the arithmetic and control circuit 1 outputs a sensor select signal to the sensor selection circuit 31 to select one sensor. Next, the arithmetic and control circuit 1 outputs a pen drive signal and starts timing by an internal timer (constituted by a counter).

The output signals of the vibration sensors 6a to 6d are amplified to predetermined levels by the preamplifier circuits 12a to 12d (signal 42). The amplified signal is selected by the sensor selection circuit 31 as described above, and is input to the absolute value circuit 32 and the band-pass filter 37. The signal input to the absolute value circuit is input to the envelope detection circuit 33 including a low-pass filter or the like, and only the envelope of the detection signal is extracted (signal 421). The envelope signal is input to a two-time differentiation circuit 34, a window signal generation circuit 35 that generates a detection window signal tw, and a level determination circuit 40.

The window signal generating circuit 35 also performs signal detection determination, and is composed of a comparator in which a detection threshold (described later) is set to the threshold. Then, when the input envelope signal (signal 421) exceeds the detection threshold value, a detection window signal (signal 46) is output. Using this detection window signal as an enable signal, a tg signal detection circuit 36 constituted by a comparator passes a part of the signal 43 from the twice differentiating circuit 34 to generate a tg signal (signal 49), and a waveform shaping circuit 39
Enter

On the other hand, the signal (signal 44) obtained from the band-pass filter 37 is t
The signal is input to the waveform shaping circuit 39 via the p signal detecting circuit 38. The tp signal detection circuit 38 generates a tp signal (signal 47) based on the detection window signal (signal 46),
This is input to the waveform shaping circuit 39.

The waveform shaping circuit 39 shapes the input tg signal and tp signal and outputs them to the arithmetic and control circuit 1 as signals indicating the arrival timing of each signal. The arithmetic and control circuit 1 measures the time width of the pulse signal by an internal counter and calculates the distance by a method described later. The waveform shaping circuit 39 generates a long pulse from the pen drive signal 41 in FIG. 3 to the detection point of the Tp signal (and Tg signal) so that the CPU can detect time. That is, the Tp and Tg signals input to the waveform shaping circuit 39 and the Tp and Tg signals output from the waveform shaping circuit 39 are pulse signals having the same time information and different shapes.

On the other hand, the envelope signal is also input to the level judgment circuit 40. Here, a determination threshold (described later) is set, and it is detected whether or not the input signal exceeds a predetermined level. The result of the determination by the level determination circuit 40 is input to the arithmetic and control circuit 1 as a determination signal. The arithmetic control circuit 1 switches the drive level (low drive level or high drive level) of the pen 3 based on the determination result.

Next, the detection threshold used in the above-described window signal generation circuit 35 and the determination threshold used in the level determination circuit 40 will be described. FIG. 4 is a diagram illustrating a detection threshold according to the present embodiment.

The signal detection level is set to a level indicated by a curve 101 in FIG. 4 from specifications such as writing pressure and angle. When the detection signal exceeds this level, signal detection is performed, and the delay time of signal arrival is measured. That is, in the window signal generation circuit 35, when the input envelope signal 421 exceeds the detection threshold, the detection of the tg signal and the tp signal is performed. The threshold of the detection level (curve 101, hereinafter referred to as detection threshold level 101) is set to a curve that attenuates with respect to distance (that is, time). The detection threshold value is equal to or higher than the highest level of S0 at the time of Low drive (naturally, it must be higher than other noise levels).
It should just be set to. As a matter of course, the lower the input, the easier it is to input. The horizontal axis in FIG. 4 can be converted to time. However, since Tp is not continuous, it does not correspond as it is, but it corresponds to Tg. The time corresponding to the horizontal axis in FIG. 4 varies depending on the configuration (used frequency, plate thickness, etc.), but since Vg is about 200 [m / sec],
It takes about several tens μsec to 200 μsec.

When the pen drive signal is driven by the power supply voltage (High drive), the detection level of S0 of the unnecessary vibration becomes maximum when conditions such as the angle, temperature, location, and pen pressure fluctuate. It is assumed that the level may rise to the level shown by the curve 102 in FIG. When such unnecessary vibration occurs, the signal naturally exceeds the detection threshold level 101, so that a normal signal is not detected and an erroneous detection is performed.

In order to avoid this erroneous detection, in the present embodiment, a determination threshold determined by the A0 / S0 ratio is provided, and when the level of the detected signal exceeds this determination threshold, the pen 3 is driven. Driving (Low driving) is performed by lowering the signal level.

First, High drive is performed, and signal detection is determined based on whether or not a detection threshold is exceeded. If the signal exceeds the detection threshold, it is further determined whether the signal level has reached the determination threshold.

The determination threshold is set for the A0 level when the maximum S0 level exceeding the detection threshold occurs. The S0 / A0 ratio is 3%, depending on the equipment configuration
Since it is about 9%, the A0 level determined by the ratio of the device is set as the determination threshold for the maximum S0 level at each distance. That is, when an A0 level signal exceeding the determination threshold is detected, there is a high possibility that the unnecessary vibration exceeds the detection threshold, and there is a high possibility that the unnecessary vibration S0 is erroneously detected. Therefore, when the detection signal level exceeds the determination threshold, the drive level of the pen 4 is lowered and the pen 4 is driven again. For example, if the drive that is 6 [dB] lower than the High drive is performed, if the ratio between the maximum level of S0 and the level of the detection threshold is within 6 [dB],
S0 surely falls below the detection threshold. Note that the S0 / A0 ratio has a different value depending on the configuration of the device (such as the thickness of the transmitting body, the material, and the detection method). When a certain configuration is decided,
The determination threshold is determined by the maximum S0 / A0 ratio expected in the configuration.

In this manner, the pen 4 is driven again at the low level, and the obtained signal (envelope signal 421) is obtained.
Exceeds the detection threshold and does not exceed the determination threshold, A0
Normal detection of the wave is performed.

Normally, signal range (dynamic range)
It is advantageous to take a large value within the power supply voltage for noise and the like. Therefore, as shown in FIG. 4, the upper limit of the output signal level from the preamplifier during the Low drive is set to be the maximum at the nearest point of the distance between the pen sensors (curve 103).
At this time, there is a region where the signal level obtained by the High drive is saturated with the power supply voltage.
Since the driving signal is used, the detection is not affected.

Since the unnecessary vibration S0 at this time is determined for the High drive, the determination threshold value is S0 in the High drive.
May be determined by the S0 / A0 ratio with respect to the maximum value of
Since there is a region where A0 is saturated during High driving and the setting of the threshold value becomes unstable, it is preferable to set a determination threshold value lower by the level ratio between the High level and the Low level (−6 [dB] in the present embodiment). . At this time, it is almost Low
The A0 upper limit of the level is the determination threshold.

In this embodiment, the detection threshold and the determination threshold used in the window signal generation circuit 35 and the level determination circuit 40 change as shown in FIG. . Therefore, in the present embodiment, the CPU of the arithmetic and control circuit 1 sets the detection threshold and the determination threshold as shown in FIG. 4 for the window signal generation circuit 45 and the level determination circuit 40 (in FIG. Omitted).

FIG. 9 is a diagram for explaining a configuration for setting a threshold value by the arithmetic and control circuit 1. In FIG. Arithmetic control circuit 1
CPU outputs the value of the detection threshold value 101 as shown in FIG. 4 to the window signal generation circuit 35 as time elapses after outputting the pen drive signal. In the window signal generation circuit 35,
Latch 351 latches this detection threshold and its output is D
/ A converter 352. The D / A converter 352 converts the detection threshold into a voltage value and supplies it to the comparator 353. The comparator 353 compares the input envelope signal with the voltage value from the D / A converter 352, and outputs the comparison result to the window signal generation unit 354. Window signal generator 3
54 generates and outputs a window vibration according to the comparison result signal.

The level judgment circuit 40 has the same configuration, and the latch 401 holds the judgment threshold from the CPU.
The D / A converter 402 converts this into a voltage value. The comparator 403 compares the input envelope signal with the voltage value from the D / A converter 402 and outputs the result as a level determination signal. In addition, in order to make the determination threshold variable depending on the distance (in time), in addition to the above configuration, the second
The illustrated window signal generation circuit 35 and the level determination circuit 40
In the above, the threshold may be varied using a CR charge / discharge circuit.

FIG. 5 is a flowchart for explaining the procedure of the coordinate detecting process according to the present embodiment. A control program for realizing a control procedure described below is stored in, for example, a ROM (not shown) in the arithmetic
(Not shown).

First, in step S1, the vibrator driving circuit 2 of the vibrating pen 3 is driven at a high level. After the driving, in step S2, it is determined whether an envelope signal exceeding the detection threshold is detected. If it is not detected, it is determined that the pen is up, and the process returns to the main process without performing any process. If an envelope exceeding the detection threshold is detected, it is determined in step S3 whether the level exceeds the determination threshold. If not, the process proceeds to step S6, and tp and tg are obtained by using the detected signal.

If it is determined in step S3 that the level of the detection signal exceeds the determination threshold, the process proceeds to step S4, where the vibrator driving circuit 2 of the vibrating pen 3 is driven at a low level. If a level exceeding the detection threshold is detected in step S5, tp and tg are calculated using the signal in step S6. If no signal exceeding the detection threshold is detected, the process returns to the main process as pen-up.

In the above flowchart, the level determination as to whether or not the signal level exceeds the determination threshold after the low level driving is not performed. This is because such a combination does not occur in the design (ie, Lo
This is because no signal exceeding the determination threshold is detected by the w driving.) However, when there is a concern such as a malfunction of the device, the level is determined even after the detection of the low drive, and if the level is over, the device is treated as an abnormality of the device (for example, a user is notified). You may do it.

In step S4, if the signal level exceeds the determination threshold, a pen drive level switching signal is generated, the pen drive level is set to the low drive level, and the pen drive signal is generated again. Perform Hereinafter, a circuit configuration for switching the drive level will be described. FIG. 6 is a diagram showing an example of a configuration of a pen driving circuit capable of switching a pen driving level.

The operation control circuit 1 supplies a pen drive level switching signal, and the signal level switches on / off of Tr1. When Tr1 is off,
A power supply level is supplied to the vibrator driving Tr3 and Tr4 (High driving level). When Tr1 is turned on, a voltage (Low drive level) determined by r1 and r2 is given to Tr2, and the voltage is supplied to Tr3 and Tr4 for driving the vibrator. As described above, after the drive level is determined by the pen drive level switching signal, the pen drive signal is supplied, and the driving of the vibrator at each drive level is realized.

The above operation is performed for other sensors, and the distance from the pen to each sensor is calculated.

Next, the t detected in step S6 is
The distance between each sensor and the input point is calculated using g and tp, and the input coordinates are calculated based on the distance. Hereinafter, the procedure for calculating the coordinates will be briefly described. Ultrasonic vibration wave transmitted from vibration pen 3 to vibration transmission plate 8, vibration sensor 6
After progressing for a time tg according to the distance to a, the vibration is detected by the vibration sensor 6a. A signal indicated by reference numeral 42 in FIG. 3 indicates a signal waveform detected by the vibration sensor 6a. Since the vibration used in this embodiment is a plate wave, the relationship between the envelope 421 and the phase 422 of the detected waveform with respect to the propagation distance in the vibration transmission plate 8 depends on the transmission distance during the vibration transmission. Change. The distance between the vibration pen 3 and the vibration sensor 6a can be detected more accurately from the group velocity Vg and the phase velocity Vp.

First, focusing only on the envelope 421, its speed is Vg. When a point on a specific waveform, for example, a point of inflection or a signal shown in FIG. 43 is detected, the vibration pen 3 and the vibration sensor The distance between 6a is
As the vibration transmission time and tg, d = Vg · tg (1) In the present embodiment, the envelope 4
The first zero-crossing point in the window signal of the second derivative signal 43 is used as the 21 points on the specific waveform.

Next, the time from the specific detection point of the phase waveform signal 422 to the first zero-cross point after the window signal 46 is represented by t.
Assuming that p (signal 47), the distance between the vibration sensor and the vibration pen is as follows: d = n · λp + 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
Is expressed as n = [(Vg · tg−Vp · tp) / λp + 1 / N] (3)

Here, N is a real number other than "0", and an appropriate value is used. The distance between the vibration pen 3 and the vibration sensor 6a can be accurately measured by substituting n obtained as described above into the expression (2).

FIG. 7 is a view for explaining a method of calculating the coordinates of the vibration input point based on the distance between the vibration input point and each vibration sensor. Based on the distances da to dd, the coordinates (x, y) of the position P of the vibration pen 3 can be obtained from the three-square theorem as shown in FIG.

X = (da + db) · (da−db) / 2X (4) or x = (dc + dd) · (dc−dd) / 2X (5) y = (da + dc) · (da−dc) / 2Y ( 6) or y = (db + dd) · (db−dd) / 2Y (7) where X and Y are the distance between the vibration sensors 6a and 6b and the distance between the vibration sensors 6c and 6d, respectively. As described above, the position coordinates of the vibration pen 3 can be detected in real time.

As described above, according to the above-described embodiment, a stable detection can be performed even if the signal level is reduced due to the pen pressure or the propagation distance by increasing the dynamic range of the signal by the High level driving. If it is highly probable that unnecessary vibrations will be detected by high-level driving, Lo
Since signal detection is performed by switching to w-level driving, erroneous detection can be prevented.

That is, the possibility of erroneous detection of unnecessary vibration is determined, and the drive level of the vibration pen is switched based on this, so that stable detection can be performed regardless of the use situation.

[Other Embodiments] In the above-described embodiment, the driving by the power supply voltage (high-level driving) and the driving by the power supply voltage are performed.
[DB] A method of driving using two types of driving (low level driving) with a reduced voltage has been described, but it is needless to say that the present invention is not limited to this.

When the S / N permits, a plurality of amplifier gains of the preamplifiers 12a to 12d for amplifying a signal from the vibration sensor are prepared instead of the drive level, and the configuration can be made in the same manner as in the above embodiment. Will be apparent to those skilled in the art.

When the input area becomes large, the distance between the pen and the sensor becomes long, and there is a possibility that the A0 signal approaches the noise level or becomes the same level. When the detection level is very low, the S / N ratio deteriorates, and normal detection becomes difficult. In such a case, a similar effect can be obtained by further switching the combination of the drive levels depending on the distance.

FIG. 8 is a diagram showing a detection threshold and a signal level when a combination of drive levels is switched according to a detection distance (detection time). Let the propagation time at the point of distance L be tL
Then, before tL, the same processing as in the above-described embodiment is performed using a combination of the drive levels M and L. After tL, the same processing as in the above-described embodiment is performed using a combination of the drive levels H and M.

That is, before tL, the drive level M
First, the pen is driven at (intermediate level). Detection threshold 801
When a signal exceeding the threshold value is detected, a comparison with the determination threshold value 803 is performed. If the detection signal does not exceed the threshold value, the value at that time is used as it is. If it exceeds, the drive level is set to L (low level) and re-drive is performed.

On the other hand, when the time tL has been exceeded, the measurement is temporarily stopped at that time, and the first drive is performed at the level H (high level). And similarly, the detection threshold 80
It monitors whether a signal exceeding 5 is detected and whether the level of the detected signal does not exceed the determination threshold value 807. If a signal exceeding the determination threshold value is detected, re-driving is performed at the level M and data is output. Get.

By providing a plurality of combinations of drive levels in accordance with the distance or the like, it is possible to prevent unnecessary vibration such as S0 or a decrease in the dynamic range due to vibration such as noise, and to provide an input equivalent with a better input feeling. .

As described above, according to each of the above embodiments, a detection threshold is provided to detect a signal from the vibration sensor, and the drive level of the vibration pen is determined based on whether the detected signal exceeds the determination threshold. By switching, the apparent dynamic range can be expanded. That is, the detection target signal (A0) at a level lower than the unnecessary signal (S0), which is expected to be generated by the High level driving, can be detected. Even with the high level drive, when the pen pressure or the like is weak, the A0 signal may be smaller than the maximum S0 signal. Even in such a case, since the detection threshold is set lower than the maximum S0, detection is possible. On the other hand, if the pen pressure or the like is high during high level driving, S0 exceeds the detection threshold.
Since the detection is performed by the w-level drive, S0 also becomes equal to or smaller than the detection threshold, and A0 can be detected. Accordingly, this is apparently the same as an increase in the dynamic range for the detection signal. For this reason, a detection target signal equal to or less than an unnecessary signal can be detected, so that a low pen pressure input can be performed, and at the same time, an allowable value for component variation and the like can be increased, and a product can be provided at low cost.

Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine, a facsimile, etc.) comprising one device Device).

An object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU) of the system or apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided on a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0066]

As described above, according to the present invention, regardless of the input state of the vibration input position, pen pressure, pen angle, etc.
A stable and good input feeling can be obtained.

[0067]

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a coordinate input device according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of a signal waveform detection circuit 9.

FIG. 3 is a diagram illustrating signal processing in the present embodiment.

FIG. 4 is a diagram illustrating a detection threshold according to the present embodiment.

FIG. 5 is a flowchart illustrating a procedure of a coordinate detection process according to the embodiment;

FIG. 6 is a diagram illustrating a configuration example of a pen driving circuit capable of switching a pen driving level.

FIG. 7 is a diagram for explaining a method of calculating coordinates of a vibration input point based on a distance between the vibration input point and each vibration sensor.

FIG. 8 is a diagram illustrating a detection threshold and a signal level when a combination of drive levels is switched according to a detection distance (detection time).

FIG. 9 is a diagram illustrating a configuration for setting a threshold value by an arithmetic control circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arithmetic control circuit 2 Oscillator drive circuit 3 Oscillator input pen 4 Oscillator 5 Nib 6a-6d Vibration sensor 7 Vibration-proof material 8 Vibration transmission board 9 Signal waveform detection circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuyuki Kobayashi, Inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Ryozo Yanagisawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside the corporation

Claims (19)

[Claims] 1. A coordinate input device for acquiring an input position of a vibration input from a vibration source on a vibration transmission plate based on a delay time required for the vibration to reach a vibration detection means, the coordinate input device comprising: A first drive unit that drives at a first drive level and generates a coordinate detection signal based on a detection signal from the vibration detection unit; and a detection signal detected by the vibration detection unit exceeds a first threshold. Determining means for determining whether the vibration signal has exceeded the first threshold; and determining whether or not the vibration source has a second drive level lower than the first drive level.
And a second driving unit that drives at the driving level of (i) and generates a signal for coordinate detection based on a detection signal from the vibration detecting unit. 2. The coordinate input device according to claim 1, wherein the first threshold value is a maximum signal value when the vibration source is driven at the second drive level. 3. The coordinate input device according to claim 1, wherein the determination unit changes the first threshold based on a lapse of time from a time when the vibration source is driven. 4. The first driving means drives the vibration source at a predetermined driving level, amplifies a signal obtained from the vibration detecting means at a first amplification factor to generate a detection signal, and When it is determined that the detection signal exceeds the first threshold, the driving unit drives the vibration source at the predetermined drive level, and converts the signal obtained from the vibration detection unit into the first amplification factor. 2. The coordinate input device according to claim 1, wherein the signal is amplified at a lower second amplification factor and is used as a detection signal. 5. The method according to claim 1, wherein the first driving means and the second driving means use the signal as a detection signal when a signal obtained from the vibration detection means exceeds a second threshold value. The coordinate input device according to claim 1. 6. The method according to claim 1, wherein the first threshold value is set to a value lower than a maximum value of the unnecessary vibration at the first drive level by a level ratio between the first drive level and the second drive level. The coordinate input device according to claim 5, wherein: 7. The coordinate input device according to claim 6, wherein said first threshold value is set to substantially a maximum value of a detection signal obtained by said second drive level. 8. The first and second driving means, based on a lapse of time from the time when the vibration source is driven, is controlled by the second driving means.
The coordinate input device according to claim 5, wherein the threshold value is changed. 9. At least two or more combinations of drive levels corresponding to the first drive level and the second drive level, and the combination of the drive levels based on the delay time of the vibration reaching the vibration detecting means. The coordinate input device according to claim 1, further comprising a change unit that changes a combination. 10. A control method of a coordinate input device for acquiring an input position of a vibration input from a vibration source on a vibration transmission plate based on a delay time until the vibration reaches a vibration detecting means, the control method comprising: A first driving step of driving a vibration source at a first drive level and generating a signal for coordinate detection based on a detection signal from the vibration detection means; and a detection signal detected by the vibration detection means is a first drive signal. A judging step of judging whether or not a threshold value has been exceeded; and, if it is determined that the detection signal has exceeded the first threshold value, the vibration source is set to a second drive level lower than the first drive level.
A second drive step of driving at a drive level of (i) and generating a signal for coordinate detection based on a detection signal from the vibration detection means. 11. The control of the coordinate input device according to claim 10, wherein the first threshold value is a maximum signal value when the vibration source is driven at the second drive level. Method. 12. The coordinate input device according to claim 10, wherein said determining step includes a step of changing said first threshold value based on a lapse of time from a time point when said vibration source is driven. Control method. 13. The first driving step drives the vibration source at a predetermined driving level, amplifies a signal obtained by the vibration detecting means at a first amplification factor to generate a detection signal, The driving step drives the vibration source at the predetermined drive level when it is determined that the detection signal has exceeded the first threshold, and converts the signal obtained from the vibration detection means into the first amplification factor. The control method for a coordinate input device according to claim 10, wherein the signal is amplified at a lower second amplification factor and is used as a detection signal. 14. The method according to claim 1, wherein in the first driving step and the second driving step, when a signal obtained from the vibration detecting means exceeds a second threshold value, the signal is used as a detection signal. A control method for a coordinate input device according to claim 10. 15. The second threshold value, wherein a ratio between the maximum value of unnecessary vibration at the first drive level and the second threshold value substantially matches a ratio between the first drive level and the second drive level. The method of controlling a coordinate input device according to claim 14, wherein the control method is determined to be performed. 16. The method according to claim 15, wherein the first threshold is set based on a maximum value of a detection signal obtained by the second drive level. 17. The coordinates according to claim 14, wherein in the first and second driving steps, the second threshold value is changed based on a lapse of time from when the vibration source is driven. Control method of input device. 18. A combination of a drive level corresponding to the first drive level and the second drive level is at least two.
The control method for a coordinate input device according to claim 10, further comprising a changing step of changing the combination of the drive levels based on a delay time of the vibration reaching the vibration detecting means. 19. A control program for controlling a coordinate input device for acquiring an input position of a vibration based on a delay time until a vibration input from a vibration source onto a vibration transmission plate reaches a vibration detecting means. A storage medium for storing,
The control program drives the vibration source at a first drive level, and generates a signal for coordinate detection based on a detection signal from the vibration detection means. A code for a determining step of determining whether or not the detected detection signal has exceeded a first threshold; and, when determining that the detection signal has exceeded the first threshold, setting the vibration source to the first drive level. Second lower than
And a code for a second driving step of generating a signal for coordinate detection based on a detection signal from the vibration detecting means.