JP3071254B2 - Coordinate input device and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a coordinate input device and method for detecting a coordinate of a designated point from a vibration transmission time from a vibration source on a vibration transmission plate, for example.

[0002]

2. Description of the Related Art Conventionally, a coordinate input device using an elastic wave has been proposed in Japanese Patent Application No. 61-149742.

As a method of correcting the origin of the coordinate input device having the same configuration, Japanese Patent Application No. 63-063181 and Japanese Patent Application No. 63-0
There is a method described in Japanese Patent No. 63180, and an apparatus for correcting coordinate accuracy using origin correction data has been proposed.

In the above proposal, the calculation of the coordinate calculation is performed as follows.

[0005] As shown in FIG.
Sensor pair S_XL・ S_XRAnd Y sensor pair S _YU・ S_YDAnd the coordinate origin
In a coordinate input plate arranged orthogonally at point O,
Origin when vibration is applied to point P located at mark (x, y)
The group delay time tgz and the phase delay time tpz in O
Data for point correction is stored for each sensor, and
The distance between each sensor and the input coordinates (x, y) are as follows.
Is calculated.

N _i = [{vg (tg _i -tgz _i ) -vp (tp _i -tpz _i )} / λ + α] (sub 1) D _i = N _i · λ + vp (tp _i -tpz _i )… (Sub 2) x = (D _l ² -D _r ² ) / 2X _RL + (D _l -D _r ) / 2… (Sub 3) y = (D _u ² -D _d ² ) / 2Y _UD + (D _u -D _d ) / 2 ... (sub 4) tg _i ; group delay time at sensor i tp _i ; phase delay time at sensor i vg; group velocity vp; phase velocity λ; wavelength (= vp / f) f; frequency D _i ; distance between input point and sensor i X _RL ; distance between x sensors (S _XR -S _XL ) distance Y _UD ; distance between y sensors (S _YU -S _YD ) distance α; integer in [] Time constant (0.5 for rounding) where i = l, r, u, d, and sensors S _XL , S _XR , S
It means the value in _YU , _SYD .

[0007]

In the above conventional example,
N _{i in the} equation (1) corresponds to a wavelength shift corresponding to the number of wavelength shifts of the detected phase delay time tp, and is always an integer. The N _i is to be calculated from the difference of the group delay tg and phase delay tp as shown in equation (sub 1), when the deformation in the waveform is caused by the angle pressing example vibration pen to the vibration transmission member, the tg An offset value is generated due to a cause such as a shift of the detection point.

FIG. 8 shows this situation. The difference ΔN between N _real before integer conversion and N after integer conversion in equation (1) is shown in FIG.
9 is an actual measurement result showing N. Each line of a, b, c, d, e corresponds to the inclination a, b, c, d, e of the pen as shown in FIG. These measurement results do not exceed the margin of N calculation ± 0.5, indicating that normal coordinate calculation can be performed. However, for example, in the case of the line a in FIG. 8, ΔN fluctuates around +0.2, and the positive margin is about +0.3, which is about half of the value of the line c, +0.5. There is a high possibility that the accuracy may be degraded due to fluctuations in the signal level due to external factors such as noise. Furthermore, in this type of coordinate input device, since the input pen is operated by a human, it is often used at a certain angle that is not vertical during normal use, so that there is a problem that a sufficient margin cannot be secured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above conventional example, and has as its object to provide a coordinate input device capable of correcting an input coordinate error caused by an inclination of an input pen and calculating a more accurate coordinate. And

[0010]

In order to achieve the above object, an input coordinate correction method and apparatus according to the present invention and a coordinate input apparatus have the following configurations.

[0011]

In order to achieve the above object, a coordinate input device according to the present invention has the following configuration. That is, the input means for designating a desired position of the coordinate input plate urges the input plate to generate an elastic wave, and the group of the elastic waves detected by the detecting means fixed at a predetermined position of the input plate. From the propagation delay time of the velocity and the propagation delay time of the phase velocity of the specific frequency component, the distance between the position designated by the input means and the detection means is calculated, and the distance designated by the input means is determined based on the calculated distance. A coordinate input device for calculating coordinates of a position, a first correction unit for correcting the distance by a value of a wavelength shift of the frequency component included in the phase delay time, and converting the wavelength shift into an integer. Integer conversion means, calculation means for calculating the difference between the value of the wavelength shift before being converted to an integer by the integer conversion means and the value of the wavelength shift after being converted to an integer, and the conversion to an integer using the value of the error Second correcting means for correcting an error due to Provided. Alternatively, the input means for designating a desired position of the coordinate input plate urges the input plate to generate an elastic wave, and the group of the elastic waves detected by the detecting means fixed at a predetermined position of the input plate. From the propagation delay time of the velocity and the propagation delay time of the phase velocity of the specific frequency component, the distance between the position designated by the input means and the detection means is calculated, and the distance designated by the input means is determined based on the calculated distance. A coordinate input device for calculating a coordinate of a position, a first correction unit for correcting the distance by a value of a wavelength shift of the frequency component included in the phase delay time, and converting the value of the wavelength shift into an integer. Integer conversion means for performing the conversion to an integer, the determination means for determining whether the error when converting the integer into an integer falls within a predetermined value range, and the error when converting the conversion to an integer within the predetermined value range by the determination means. Is determined not to fit Specified position by said input means and comprises a determining means for determining to be invalid. To achieve the above object, a coordinate input method according to the present invention has the following configuration. That is, the input means for designating a desired position of the coordinate input plate urges the input plate to generate an elastic wave, and the group of the elastic waves detected by the detecting means fixed at a predetermined position of the input plate. From the propagation delay time of the velocity and the propagation delay time of the phase velocity of the specific frequency component, the distance between the position designated by the input means and the detection means is calculated, and the distance designated by the input means is determined based on the calculated distance. A coordinate input method for calculating a coordinate of a position, wherein a first correction step of correcting the distance by a value of a wavelength shift of the frequency component included in the phase delay time, and converting the wavelength shift into an integer. Integer conversion step, a calculation step of calculating the difference between the value of the wavelength shift before being converted to an integer in the integer conversion step and the value of the wavelength shift after being converted to an integer, and converting the integer using the error value A second correction step for correcting an error due to Provided. Alternatively, the input means for designating a desired position of the coordinate input plate urges the input plate to generate an elastic wave, and the group of the elastic waves detected by the detecting means fixed at a predetermined position of the input plate. From the propagation delay time of the velocity and the propagation delay time of the phase velocity of the specific frequency component, the distance between the position designated by the input means and the detection means is calculated, and the distance designated by the input means is determined based on the calculated distance. A coordinate input method for calculating a coordinate of a position, wherein a first correction step of correcting the distance by a value of a wavelength shift of the frequency component included in the phase delay time, and converting the value of the wavelength shift into an integer Integer conversion step, a determination step for determining whether an error when converting to an integer by the integer conversion is within a predetermined value range, and an error when converting to an integer by the determination step is within a predetermined value range. Is determined not to fit Specified position by the input means and includes a determination step of determining to be invalid.

Further, the input plate is urged by input means for designating a desired position of the coordinate input plate to generate an elastic wave,
From the propagation delay time of the group velocity of the elastic wave detected by the detection means fixed to a predetermined position of the input plate and the propagation delay time of the phase velocity of a specific frequency component, the position designated by the input means A coordinate input device that calculates a distance between the frequency component and the detection means, and calculates a coordinate of a position designated by the input means based on the distance, wherein a value of a wavelength shift of the frequency component included in the phase delay time A first correction unit that corrects the distance only, an integer conversion unit that converts the value of the wavelength shift into an integer, and determines whether an error generated by the integer conversion unit when converting into an integer falls within a predetermined value range. A determination unit that determines that the designation of the position by the input unit is invalid if the determination unit determines that the error at the time of conversion into an integer does not fall within a predetermined value range.

[0013]

With the above arrangement, the coordinate input device of the present invention calculates the distance to the position specified by the input means, and determines how many wavelengths of the received vibration component deviate from the distance.
Correction is performed so that the calculated deviation error is minimized.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

<Structure> FIG. 1 shows the structure of a coordinate input device adopting the present invention. The coordinate input device shown in FIG. 1 constitutes an information input / output device for characters, figures, images and the like together with a display 18 having a display system such as a dot matrix system.

In FIG. 1, reference numeral 8 denotes a vibration transmission plate made of acrylic or glass plate, which transmits the vibration transmitted from the vibration pen 3 to four vibration sensors 6 provided around the vibration pen. introduce. In the coordinate detection using the vibration pen in the present embodiment, the transmission time of the ultrasonic vibration transmitted from the vibration pen 3 to the vibration sensor 6 via the vibration transmission plate 8 is measured, so that the vibration transmission plate 8 of the vibration pen 3 is measured. Find the coordinates above.

The vibration transmission plate 8 is arranged on a display 18 such as a CRT (or a liquid crystal display) capable of displaying dots, and performs dot display at a position traced by the vibration pen 3. That is, the detected vibration pen 3
Is displayed at a position on the display 18 corresponding to the coordinates of the vibrating pen 3, and an image composed of elements such as points and lines input by the vibrating pen 3 is the locus of the vibrating pen as if writing on paper. Appears after.

Further, according to such a configuration, the display 18
For example, an input method may be used in which a menu display is performed, the menu item is selected by a vibration pen, or a prompt is displayed to bring the vibration pen 3 into contact with a predetermined position.

The vibrating pen 3 for transmitting the ultrasonic vibration to the vibration transmitting plate 8 includes a vibrator 4 having a piezoelectric element or the like therein.
And transmits the ultrasonic vibration generated by the vibrator 4 to the vibration transmission plate 8 via the horn portion 5 having a sharp tip.

FIG. 2 shows the structure of the vibration pen 3. The vibrator 4 built in the vibrating pen 3 is driven by the vibrator drive circuit 2. The drive signal of the vibrator 4 is supplied as a low-level pulse signal from the arithmetic and control circuit 1 of FIG. 1 and is amplified at a predetermined gain by the vibrator drive circuit 2 capable of low impedance driving. 4 is applied.

The electric drive signal is converted into mechanical ultrasonic vibration by the vibrator 4 and transmitted to the diaphragm 8 via the horn 5.

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 such as acrylic or glass. In driving the vibrator, a vibration mode in which the vibrator 4 mainly vibrates in the vertical direction of FIG. Further, by setting the vibration frequency of the vibrator 4 to the resonance frequency of the vibrator 4, efficient vibration conversion is possible.

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

Referring again to FIG. 1, the vibration sensor 6 provided at the end of the vibration transmission plate 8 is also composed of a mechanical to electrical conversion element such as a piezoelectric element. The output signals of the three vibration sensors 6 are input to the waveform detection circuit 6 and are converted into detection signals that can be processed by the arithmetic and control circuit 1 at the subsequent stage. The arithmetic and control circuit 1 measures the vibration transmission time, and detects the coordinate position of the vibration pen 3 on the vibration transmission plate 8.

The detected coordinate information of the vibration pen 3 is processed in the arithmetic and control circuit 1 in accordance with the output system by the display 18. That is, the arithmetic control circuit controls the output operation of the display 18 via the display drive circuit 10 based on the input coordinates.

<Description of Arithmetic Control Circuit> FIG. 3 shows the structure of the arithmetic control circuit 1 of FIG. Here, a structure of a drive system of the vibration pen 3 and a vibration detection system by the vibration sensor 6 is mainly shown.

The microcomputer 11 has an internal counter, a ROM and a RAM. The drive signal generation circuit 12 outputs a drive pulse of a predetermined frequency to the vibrator drive circuit 2 of FIG.
1 is started in synchronization with the circuit for coordinate calculation.

The count value of the counter 13 is latched by the microcomputer 11 to the latch circuit 14.

On the other hand, the waveform detection circuit 9 outputs timing information of a detection signal for measuring a vibration transmission time for coordinate detection from an output of the vibration sensor 6 as described later. These pieces of timing information are input to the input ports 15, respectively.

The timing signal input from the waveform detection circuit 9 is input to the input port 15 and is stored in a storage area corresponding to each vibration sensor 6 in the latch circuit 14, and the result is transmitted to the microcomputer 11. That is, the vibration transmission time is expressed as the latch value of the output data of the counter 13, and the coordinate calculation is performed based on the vibration transmission time value. At this time, the determination circuit 16 determines whether all the timing information of the waveform detection from the plurality of vibration sensors 6 has been input, and notifies the microcomputer 11 of the determination. The output control processing of the display 18 is performed via the input / output port 17. <Description of Coordinate Calculation> FIG. 4 is a diagram for explaining a detection waveform input to the waveform detection circuit 9 of FIG. In FIG. 4, what is indicated by reference numeral 41 is a drive signal pulse applied to the vibration pen 3. The ultrasonic vibration transmitted to the vibration transmission plate 8 from the vibration pen 3 driven by such a waveform passes through the vibration transmission plate 8 and is detected by the vibration sensor 6.

After traveling for a time tg according to the distance to the vibration sensor 6 in the vibration transmission plate 8, the vibration reaches the vibration sensor 6. Reference numeral 42 in FIG. 4 indicates a signal waveform detected by the vibration sensor 6. The plate wave used in this embodiment is a dispersive wave, and therefore, the relationship between the envelope 421 and the phase 422 of the detected waveform changes according to the vibration transmission distance.

Here, the traveling speed of the envelope is represented by the group velocity V
g, and the phase velocity is Vp. From the difference between the group velocity and the phase velocity, the distance between the vibration pen 3 and the vibration sensor 6 can be detected.

For measuring the two vibration transmission times tg and tp shown in FIG. 3, the waveform detection circuit 9 can be configured as shown in FIG. 5, for example.

In FIG. 5, the output signal of the vibration sensor 6 is amplified to a predetermined level by the amplifier circuit 51 described above.

The amplified signal is supplied to an envelope detection circuit 5
2 and only the envelope of the detection signal is extracted. The timing of the extracted envelope peak is detected by an envelope peak detection circuit 53.
An envelope delay time detection signal Tg having a predetermined waveform is formed from a peak detection signal by a signal detection circuit 54 composed of a monomultivibrator or the like.
Is input to

Further, a phase delay time detection signal Tp is formed by the detection circuit 58 from the timing of the Tg signal and the original signal delayed by the delay time adjustment circuit 57, and is input to the arithmetic and control circuit 1.

That is, the Tg signal is converted into a pulse having a predetermined width by the monostable multivibrator 55. Also,
The comparator level supply circuit 56 forms a threshold value for detecting a signal tp according to the pulse timing. As a result, the comparator level supply circuit 56 forms a signal 44 having a level and timing as indicated by reference numeral 44 in FIG.

That is, the monostable multivibrator 55
The comparator level supply circuit 56 is provided so that the measurement of the phase delay time operates only for a predetermined time after the detection of the envelope peak.

This signal is input to a detection circuit 58 composed of a comparator or the like, and is compared with a detection waveform delayed as shown in FIG. 4, and as a result, a tp detection pulse 45 is formed.

The circuit shown above is for one vibration sensor 6, and the same circuit is provided for each of the other sensors. If the number of sensors is generalized to h, the envelope delay times Tg1 to h and the phase delay times Tp1 to Tp1
h detection signals of h are input to the arithmetic and control circuit 1.

In the arithmetic and control circuit shown in FIG.
The Tp1 to h signals are input from the input port 15, the respective timings are taken out, and the count value of the counter 13 is taken in the latch circuit 14. As described above, since the counter 13 is started in synchronization with the driving of the vibrating pen, the latch circuit 14 takes in data indicating the delay time of each of the envelope and the phase.

Now, as shown in FIG. 6, four vibration sensors 6 are arranged at positions S _XL , S _XR , S _YU , and S _YD around the vibration transmission plate 8, and the center of the transmission plate 8 is orthogonal to the origin O. Arrange so that it is located on the coordinate axis. The linear distances D _l , _Dr , _Du , and D _d from the position P of the vibration pen 3 to the position of each vibration sensor 6 can be obtained by the processing described with reference to FIG. The arithmetic control circuit 1 further calculates the linear distances D _l , _Dr , _Du ,
Position P of coordinates of the vibration pen 3 on the basis of the D _d (x, y) 3
It can be obtained from the square theorem.

N _i = [(vg · tg _i -vp · tp _i ) / λ + α] (1) D _i = vp · tp _i + N _i · λ (2) x = (D _l ² − D _r ² ) / 2X _RL + (D _l -D _r ) / 2 ... (3) y = (D _u ² -D _d ² ) / 2Y _UD + (D _u -D _d ) / 2 ... (4) And tg _i ; group delay time at sensor i (origin corrected) tp _i ; phase delay time at sensor i (origin corrected) vg; group velocity vp; phase velocity λ; wavelength (= vp / f) f ; Frequency D _i ; Distance between input point and sensor i X _RL ; Distance between x sensors (S _XR -S _XL ) Distance Y _UD ; Distance between y sensors (S _YU -S _YD ) Distance α; Integer time constant in [] (0.5 for rounding) Also, here, i = l, r, u, d, and each sensor S _XL・ S
_It means the value in _XR・ S _YU・ S _YD .

As described above, the designated coordinates (x, y) can be obtained from Expressions (1) to (4). Where N
Is a number for correcting the difference between the distance based on the group velocity / delay and the distance based on the phase velocity / delay for the distance calculated from the propagation delay time of the vibration, and is given as an integer. N
Is an amount originally given as an integer. However, since the first term in [] of Expression (1) is not always an integer due to a measurement error or the like, a correction amount α is given for conversion to an integer. For this reason, the coordinates actually calculated are (x ′, y ′) including an error when N is converted to an integer. The following method is used to easily correct this and bring it closer to the true coordinates (x, y).

<Integer Conversion Error> From equation (1), N = [{(vg / vp) tg-tp} / λ + α]; [] Integer Conversion ... (5) N _real = {(vg / vp ) tg-tp} / λ + α (6) Since the difference between N and N _real is ΔN, ΔN = N _real −N (7)

If tg and tp in equations (5) and (6) and other parameters do not include an error, the value of ΔN is 0. But in real life situations,
Since the value of each parameter includes an error, a value of ΔN is generated.

In particular, as described above, the input pen is
On the other hand, when tilted from the vertical, the fluctuation of the group delay time tg
Is remarkable and becomes a main cause of the ΔN fluctuation. Now,
If this ΔN fluctuation fluctuates in the same width for both positive and negative from 0
In this case, α = 0.5 as shown in the above equation (5).
If we convert to integers, we can get the correct value of N
You. However, in normal use, the input pen
Is often limited to the time between
If a pen input is made at the point ΔN = + as shown in FIG.
It shows a value biased to one side between 0.2 and 0. Where both positive and negative
In order to obtain the maximum margin on the side, the central value of the variation of ΔN
May be changed to 0 to change the value of α. In other words, α
Instead α ′ = α − ｛(ΔN_max −ΔN_min ) / 2 + ΔN_min ８ (8) Here, (0 ≦ α ′ <1) and (0 ≦ α <1) (9) are used as correction amounts. α is the value used when calculating ΔN.
The margin of the system itself
If the contract is not equal on the positive and negative sides, α = 0.5,
What is necessary is just to set the value corresponding to it. In the example of FIG.
α = 0.5, ΔN _max = 0.2, ΔN_min = 0
Α ′ = 0.4. This puts FIG. 10 in FIG.
It has been changed.

<Explanation of Flowchart> FIG. 7 shows a flowchart of an embodiment of a method for determining the correction amount α ′ using the above equation (8).

First, in steps S11 and S12, variables N _max and N _min are initialized and a counter i for counting the number of times of sampling is cleared. The variables N _max and N _min store the maximum and minimum values of ΔN, respectively.

After the initialization, sampling is started in step S13. Sampling selects appropriate coordinates and inputs coordinates at that position. If coordinates are input, four sensors S _XL attached to the end of the vibration transmission plate
Measure the group delay time tg and the phase delay time tp in S _{XR ＳS YU} ＳS _YD .

In step S14, the observed tp · t
Using the g value, ΔN is calculated from the equations (5), (6), and (7). The values of vp · vg and λ are known here.

In step S15, the obtained ΔN is N
greater than or determined than the current value of _max, greater if N _max
Is substituted for (S16). In step S17, it is similarly determined whether ΔN is smaller than N _min , and if ΔN is smaller, the value is substituted for N _min (S18).

When one sample data has been processed, 1 is added to a counter i for counting the number of samples in step S19, and then in step S20, the value of the counter i is determined whether or not a predetermined number of samples has been reached. If not, the process returns to step S13 to process another sample data. If the sampling is completed, α ′ is determined based on the equation (8) in step S21 from the minimum and maximum of ΔN obtained up to that time, and thereafter, the coordinates are calculated using α ′ as α (S22).

With the above procedure, the correction amount α required for calculating the coordinates can be obtained as a value that enables more accurate calculation of the coordinates.

In the above procedure, the number of samples is arbitrary, and may be set so as to obtain a desired accuracy. In the present embodiment, the sampling period is defined by the number of samples, but may be defined by other means such as by time.

As an example of the operation procedure for performing the sampling in the above flow chart, a case where the user himself performs the operation will be described.

First, after the power is turned on, the mode is switched to a mode for determining the correction amount α 'by a mode switching means such as a menu or an icon by a switch or software at an appropriate time. In this mode, α ′ is determined using the procedure of the flow described above. At this time, the user writes appropriate characters or figures on the coordinate input board according to free handwriting or a format prepared in advance. As the sample data, for example, if various patterns such as a date and various figures (circle, square, etc.) are input, a better value of α ′ can be obtained.

By sampling in this way,
The correction amount α can be maintained in a state closer to the usage environment of the user, and a stable and accurate coordinate input device with a wider margin for errors can be provided. Further, if the obtained value of the correction amount α is stored and held in a non-volatile memory (for example, an EEPROM) or the like, the correction sampling does not have to be performed thereafter, and the burden on the user is reduced.

[0059]

[Other Embodiments] In the above embodiment, ΔN is calculated and the correction amount α ′ is calculated.
Is started by explicitly instructing the mode for determining the coordinate. However, this may be performed during a normal coordinate input operation without causing the user to select the mode. That is, ΔN is calculated each time a normal coordinate is input, and the correction amount α is calculated each time a certain number of samplings is reached, and the value is updated. With this configuration, it is possible to correct the coordinate calculation without the user performing the sampling operation. Further, in order to frequently calculate ΔN, it is possible to determine the validity of the calculated coordinate values. In other words, when calculating the input coordinates,
Calculate ΔN for each sensor. If this value ΔN is ±
When the value is close to 0.5, that is, when the margin is close to 0, it can be determined that this data has a high possibility of causing an error in the obtained coordinate value. If therefore the ΔN exceeding a preset threshold value ± N _th is calculated, By invalidating the coordinate value inputted at that time, it possible to eliminate the output erroneously.

In this case, the value of the threshold value ± N _th may be determined from the maximum value and the minimum value by sampling ΔN at the time of shipment, for example. Alternatively, for example, the average value may be determined as a center value from a range of an integral multiple of the standard deviation. In addition, it is also possible to set a threshold as a constant as a specification, instead of determining the threshold for each device body.

The present invention may be applied to an apparatus comprising a plurality of devices, may be applied to an apparatus comprising a single device, or may be achieved by supplying a program to a system or an apparatus. Needless to say, it can also be applied to.

[0062]

As described above, according to the present invention,
An error in the input coordinates caused by the inclination of the input pen is corrected, and more accurate calculation of the coordinates can be performed.

[Brief description of the drawings]

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

FIG. 2 is a configuration of a coordinate input pen according to the embodiment.

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

FIG. 4 is an explanatory diagram of obtaining coordinates from the propagation of elasticity.

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

FIG. 6 is a layout diagram of a vibration sensor according to the embodiment.

FIG. 7 is a flowchart for determining a correction amount.

FIG. 8 is a graph of variation of ΔN with respect to pen angle.

FIG. 9 shows a relationship between a pen angle and a sensor.

FIG. 10 is a sampling example of ΔN.

FIG. 11 is a graph after correction of a sampling example of ΔN.

[Explanation of symbols]

 1 arithmetic control circuit, 2 vibrator driving circuit, 3 vibrating pen, 6 vibration sensor, 8 vibration transmission plate, 9 signal waveform detecting circuit, 10 display driving circuit, 18 display.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinnosuke Taniishi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Katsuyuki Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yuichiro Yoshimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-61-33523 (JP, A) JP-A-2-130614 ( JP, A) JP-A-63-100531 (JP, A) JP-A-1-124015 (JP, A) JP-A-1-201714 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) G06F 3/03

Claims (4)

(57) [Claims] 1. An elastic wave is generated by energizing said input plate by input means for designating a desired position of a coordinate input plate, and said elasticity is detected by detection means fixed at a predetermined position of said input plate. From the propagation delay time of the group velocity of the wave and the propagation delay time of the phase velocity of the specific frequency component, the distance between the position designated by the input means and the detection means is calculated, and based on the calculated distance, the input means A coordinate input device for calculating coordinates of a designated position, a first correction unit configured to correct the distance by a value of a wavelength shift of the frequency component included in the phase delay time; Integer conversion means for converting to an integer, calculation means for calculating a difference between the value of the wavelength shift before being converted to an integer by the integer conversion means and the value of the wavelength shift after being converted to an integer, using the error value Second for correcting the error due to the integer conversion
A coordinate input device comprising: 2. An elastic wave is generated by urging the input plate by input means for designating a desired position of a coordinate input plate, and the elasticity is detected by a detecting means fixed at a predetermined position of the input plate. From the propagation delay time of the group velocity of the wave and the propagation delay time of the phase velocity of the specific frequency component, the distance between the position designated by the input means and the detection means is calculated, and based on the calculated distance, the input means A coordinate input device that calculates coordinates of a designated position, wherein: a first correction unit that corrects the distance by a value of a wavelength shift of the frequency component included in the phase delay time; and a value of the wavelength shift. Integer converting means for converting an integer into an integer; determining means for determining whether an error in converting the integer into an integer falls within a predetermined value range; Not within the range of Coordinate input apparatus comprising: a determining means for specifying the position by said input means to be determined to be invalid. 3. An elastic wave is generated by urging the input plate with input means for designating a desired position of the coordinate input plate, and the elasticity is detected by a detection means fixed at a predetermined position on the input plate. From the propagation delay time of the group velocity of the wave and the propagation delay time of the phase velocity of the specific frequency component, the distance between the position designated by the input means and the detection means is calculated, and based on the calculated distance, the input means A coordinate input method for calculating coordinates of a designated position, comprising: a first correction step of correcting the distance by a value of a wavelength shift of the frequency component included in the phase delay time; An integer conversion step of converting the integer value into a whole; a calculation step of calculating a difference between a value of the wavelength shift before the conversion into an integer in the integer conversion step and a value of the wavelength shift after the conversion into an integer; Second for correcting the error due to the integer conversion
And a correction step. 4. An elastic wave is generated by urging the input plate by input means for designating a desired position of the coordinate input plate, and the elasticity is detected by a detecting means fixed at a predetermined position of the input plate. From the propagation delay time of the group velocity of the wave and the propagation delay time of the phase velocity of the specific frequency component, the distance between the position designated by the input means and the detection means is calculated, and based on the calculated distance, the input means A coordinate input method for calculating coordinates of a designated position, wherein: a first correction step of correcting the distance by a value of a wavelength shift of the frequency component included in the phase delay time; and a value of the wavelength shift. An integer conversion step of converting an integer into an integer; a determination step of determining whether an error in converting the integer into an integer falls within a predetermined value range; and an error in converting the integer into the integer by the determination step is a predetermined value. Not within the range of Coordinate input method characterized by specifying the position by said input means and is provided with a determining step of determining to be invalid.