JPH01237712A - Coordinate input device - Google Patents

Abstract

PURPOSE:To obtain an exact coordinate value by constituting a coordinate input device so that a circuit delay time and an off-set time can not be included into respective oscillation transmission times from a prescribed point on an oscillation transmission board to an oscillating sensor and from an oscillating pen to the oscillating sensor. CONSTITUTION:A coordinate input is executed by an oscillating pen 3 to an input tablet, which is composed of an oscillation transmission board 8, and according to an inputted coordinate signal, an input picture is displayed on a display 11' to be composed of a CRT which is overlapped and arranged to the input tablet. The transmission board 8 is made of acrylic resin and a glass board, etc., whose edge is surrounded by a reflection preventing member 7 of silicone rubber, etc., and oscillation to be transmitted from the oscillating pen 3 is added to three oscillating sensors 6 which are provided in corner parts. Thus, a coordinate track to be traced by the pen 3 is menu-displayed on the display 11' and the coordinate without delay and off-set can be obtained.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention detects vibrations input from a coordinate input device, particularly a vibrating pen, using a plurality of vibration sensors provided on a vibration transmitting plate, and transmits the vibrations of the vibrating pen. This invention relates to a coordinate input device that detects coordinates on a board.

[Prior Art] In the bipedal coordinate detection method, the structure of the vibration transmission plate constituting the input tablet is simple, and a transparent material can be used as the vibration transmission plate, so it is suitable for display devices, manuscripts, etc. There are advantages such as being able to perform Rn overlappingly.

In this type of coordinate input device, input vibration from the vibrating pen is detected by multiple vibration sensors provided on the vibration transmission plate. Correct coordinate values cannot be detected unless the influence of circuit delay time is corrected. The circuit delay includes not only the electrical circuit but also the inherent delay of the circuit in which vibration is mechanically transmitted between the vibrating pen and the vibration transmission plate.

[Problems to be Solved by the Invention] Figure 8 shows the group delay time tg during which the envelope of the vibration waveform travels a certain distance, with the horizontal axis representing time t and the vertical axis representing the vibration transmission distance from the input point to the vibration sensor. This shows the change in the phase delay time tp during which the phase of the waveform progresses.

As shown in the figure, the circuit delay time et is always included even at a distance of 0, and the curves (straight lines) of each delay time are offset to the right of the graph. In addition, although the phase waveform produces a regular phase delay as shown in the figure depending on the wavelength, the difference tof between the group delay time tg and the phase delay time at the distance glO, that is, the phase offset is due to the influence of the circuit II delay time. Change.

By detecting the transverse wave component on the vibration transmission plate, the vibration transmission time can be determined by a! As a constant method, a method is known in which the vibration transmission time is determined using both the group delay time tg and the phase delay time tp. Unless this correction is made, it is not possible to obtain a vibration transmission time that is short.

For this reason, conventional methods have been known in which the vibration transmission time is corrected by recording a correction value according to the average circuit delay time et and phase offset tof measured in advance, and subtracting this from the constant value A. There is.

However, this circuit delay time et and phase offset 7 to
To determine f, it is necessary to perform calculations on data sampled at a certain point using constants such as group velocity, phase velocity, and period. Therefore, errors in values such as velocity, and Calculation errors may lead to a decrease in accuracy in determining coordinates.

Furthermore, because the actual circuit delay time varies depending on environmental changes such as temperature, it has been reported that conventional methods cannot accurately measure vibration propagation time regardless of changes in environmental conditions.

The object of the present invention is to solve the above problems.

[Means for Solving the Problems 1] In order to solve the problems from ' to In a coordinate human-powered device that detects coordinates on a vibration transmission plate, a vibration transmission time of vibration input from an arbitrary input point on the vibration transmission plate to each vibration sensor and a predetermined vibration transmission time are determined based on the vibration transmission time. means for storing the coordinates of the arbitrary input point as a correction value using a calculation method; and measuring the vibration transmission time of each vibration sensor from the coordinate input point by the vibrating pen; Subtract the stored correction value of the vibration transmission time to calculate the vibration transmission time corresponding to the distance from the designated input point to the coordinate input point, and calculate this time value and the arbitrary input point noted above. We adopted a configuration that includes a control stage that performs coordinate calculations based on coordinate values.

[Sakukawa] According to the above configuration, the vibration transmission time from the arbitrary input point to each vibration sensor and the vibration transmission time from the input point to each vibration sensor are similarly dependent on circuit delay time and phase offset time. are included, so by subtracting these, it is possible to calculate the vibration transmission time with the circuit delay time and phase offset time removed. This vibration transmission time corresponds to the distance from an arbitrary point measured from the vibration sensor position to the coordinate input point, so if coordinate calculations are performed based on this vibration transmission time, regardless of the effects of circuit delay time and phase offset time, Accurate coordinate images can be obtained quickly.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 shows the structure of an information input/output device employing the present invention. The information input/output device shown in FIG. 1 inputs coordinates to an input tablet consisting of a vibration transmission plate 8 using a shaking i-pen 3, and a display 11 consisting of a CRT placed over the input tablet according to the input coordinate information. The input image is displayed at .

In the figure, the reference numeral 8 denotes a vibration transmission plate made of acrylic, glass, etc., which transmits the vibration transmitted from the vibrating pen 3 to the vibration sensor 6 provided at the corner of the vibration pen 3. The vibration is transmitted from the pen 3 to the vibration sensor 6 via the vibration transmission plate 8. By measuring the transmission time of the tlfl sonic vibration, the coordinates of the vibrating pen 3 on the vibration transmitting plate 8 are detected.

The vibration/dynamic transmission plate 8 has an anti-reflection material 7 made of silicone rubber or the like around its periphery to prevent vibrations transmitted from the vibrating pen 3 from being reflected at the periphery and returning toward the center. Supported by

The vibration transmitting plate 8 is placed above a display device 11° such as a CRT (or liquid crystal display) capable of displaying dots, and displays a dot at each position traced by the vibrating pen 3. . That is, a dot is displayed at the position of the display 11'h corresponding to the detected coordinates of the vibrating pen 3, and the image composed of elements such as points and lines inputted by the vibrating pen 3 is displayed as if it were written on paper. Appears after the trajectory of the vibrating pen as if it were done.

Further, according to such a configuration, a menu is displayed on the display device tt', and inputs such as having the vibrating pen select a menu item or displaying a prompt and touching the vibrating pen 3 at a predetermined position can be performed. A method can also be used.

Furthermore, in this embodiment, a mark 8a is provided at a predetermined position (the position is completely arbitrary) on the input surface of the vibration transmitting plate 8, and the coordinates of this mark 8a are stored in advance in a ROM etc. Vibration is performed manually, the vibration transmission time to each vibration sensor 6 is measured, and this measured value is used to correct the vibration transmission time. The correction method will be explained in detail later.

The vibration pen 3 that inputs ultrasonic vibration to the vibration transmission plate 8 is
It has a vibrator 4 made of a piezoelectric element or the like inside, and transmits ultrasonic vibrations generated by the vibrator 4 to a vibration transmission plate 8 via a horn portion 5 having a sharp tip.

FIG. 2 shows the structure of the vibrating pen 3. A vibrator 4 built into the vibrating pen 3 is driven by a vibrator drive circuit 2. The drive signal for the vibrator 4 is supplied as a low-level pulse signal from the arithmetic and control circuit 1 shown in FIG. is applied to

, the electrical drive signal is transmitted to the mechanical ifi by the vibrator 4.
The sound waves are converted into sound vibrations and transmitted to the diaphragm 8 via the horn section 5 .

The vibration frequency of the vibrator 4 is selected to a value that can generate plate waves on the vibration transmission plate 8 made of acrylic, glass, or the like. Further, when driving the vibrator, a vibration mode is selected in which the vibrator 4 mainly vibrates in the vertical direction in FIG. 2 with respect to the vibration transmission plate 8. Also, the vibration frequency of the vibrator 4 is set to
Efficient vibration conversion is possible by setting the resonance frequency to .

The elastic waves transmitted to the vibration transmission plate 8 as shown in L are plate waves, which have the advantage of being less affected by scratches, obstacles, etc. on the surface of the vibration transmission plate 8 compared to surface waves.

Again, in FIG. 1, the vibration sensor 6 provided at the corner of the vibration transmission plate 8 is also constituted by a mechanical to electrical conversion element such as a piezoelectric element. The output signals of each of the three vibration sensors 6 are input to a waveform detection circuit 9, and the timing of vibration arrival at each sensor is detected by waveform detection processing described later. This detection timing signal is input to the arithmetic control circuit 2.

The arithmetic control circuit 1 detects the vibration transmission time to each sensor based on the detection timing input from the wave detection circuit, and further detects the coordinate input position of the vibrating pen 3 on the vibration transmission plate 8 from this vibration transmission time. do.

The detected coordinate information of the vibrating pen 3 is processed in the arithmetic control circuit 1 according to the output method by the display 11'.

That is, the arithmetic control circuit controls the output operation of the display 11° via the video signal processing device 10 based on the input coordinate information.

FIG. 3 shows the structure of the arithmetic control circuit l shown in FIG.

Here, the structure of the drive system of the vibrating pen 3 and the vibration detection system using the vibration sensor 6 are mainly shown.

The microcomputer 11 has an internal counter and a ROM 11.
It has built-in RAMI a and RAMI b. ROM11
The coordinate value of the previous mark 8a is stored in a. Also,
The RAM 1lb stores a correction value used for vibration transmission time correction, which will be described later, that is, the transmission time of manually applied vibration from the mark 8a of the vibration transmission plate 8 to each vibration sensor 6.

The drive signal generating circuit 12 outputs a drive pulse of a predetermined frequency to the vibrator drive circuit 2 shown in FIG. 1, and is activated by the microcomputer 11 in synchronization with the coordinate calculation circuit.

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

On the other hand, the waveform detection circuit 9 outputs timing information of a detection signal for measuring vibration transmission time from the output of the vibration sensor 6 as described later. These 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 capo-F15, stored in the 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 a latch value of the output data of the counter 13, and coordinate calculation is performed using this vibration transmission time value. At this time, the determination circuit 16 determines whether all waveform detection timing information from the plurality of vibration sensors 6 has been input, and
Notify 1.

Output control processing for the display device 11' is performed via an input/output capo 117.

FIG. 4 explains the detected waveform input to the waveform detection circuit 9 of FIG. 1 and the vibration transmission time measurement process based on the detected waveform. In FIG. 4, reference numeral 41 indicates a drive signal pulse applied to the vibrating pen 3. Ultrasonic vibrations transmitted from the vibrating pen 3 driven by such a waveform to the vibration transmission plate 8 pass through the vibration transmission plate 8 and are detected by the vibration sensor 6.

After traveling within the vibration transmission plate 8 for a time tg corresponding to the distance ζ to the vibration sensor 6, 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.

Therefore, the relationship between the envelope 421 and the phase 422 of the detected waveform changes depending on the vibration transmission distance.

Here, the speed at which the envelope advances is assumed to be group velocity Vg, and the phase velocity is assumed to be Vp. The distance between the vibrating pen 3 and the vibration sensor 6 can be detected from the difference in group velocity and phase velocity.

First, if we focus only on the envelope 421, its velocity is Vg, and if we detect a certain waveform point, for example, the peak, as indicated by reference numeral 43 in FIG. The distance rad is the vibration transmission time tg, and d=Vg fist tg
(1) Although this equation relates to one of the vibration sensors 6, the distances between the other two vibration sensors 6 and the vibration pen 3 can be expressed using the same equation.

Furthermore, in order to determine coordinate values with higher precision, the phase waveform 4 shown in FIG.
22 specific detection points, for example, if the time from the imaging application to the zero cross point after passing the peak is tp, the distance between the vibration sensor and the vibration pen is d=n*input p+Vp IIt p - (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 n=[(
Vg -t g-Vp ・t p)/input p'+ 1
7 N ]...(3) It is shown as follows. Here, N is a real number other than 0, and an appropriate value is used. For example, if N=2 and it is within one exhibiting wavelength, n can be determined.

By substituting n determined as above into equation (2), the distance between the vibrating pen 3 and the vibration sensor 6 can be accurately measured.

In order to measure the two vibration transmission times tg and tp shown in FIG. 1, 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 amplification circuit 51 described above.

The amplified signal is input to the envelope detection circuit 52, and only the envelope of the detection signal is extracted. The timing of the peak of the extracted envelope is detected by the envelope peak detection circuit 53. The peak detection signal is formed into an envelope delay time detection signal Tg having a predetermined waveform by a signal detection circuit 54 composed of a mono-multivibrator or the like, and is inputted to the arithmetic control circuit l.

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

That is, it is converted into a pulse of a predetermined width by the Tg multiplied signal monostable multivibrator 55. Further, the comparator level supply circuit 56 outputs t according to this pulse timing.
Form a threshold for detecting the p signal. As a result, the comparator level supply circuit 56 is connected to the reference numeral 44 in FIG.
A signal 44 having a level and timing as follows is generated and input to the detection circuit 58.

That is, the monostable multivibrator 55 and the comparator level supply circuit 56 are used to ensure that the phase delay time measurement is activated only for a certain period of time after the envelope peak is detected.

This signal is sent to a detection circuit 5 consisting of a comparator etc.
8 and is compared with the delayed detection waveform as shown in FIG.

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, then h detection signals each of envelope delay time Tgl-h and phase delay time Tpl-h are input to the arithmetic control circuit l.

In the arithmetic control circuit of FIG. 3, the above Tgl~h, Tp
The 1-h signal is input manually from the input port 15, and the count value of the counter 13 is taken into the latch circuit 14 using each timing as a trigger. As described above, since the counter 13 is started in synchronization with the driving of the vibrating pen, the latch circuit 14 receives data indicating the respective delay times of the envelope and the phase.

When three vibration sensors 6 are arranged at the corners of the vibration transmission plate 8 at positions St to S3 as shown in FIG. 6, the position i1 of the vibrating pen 3 is determined by the process explained in connection with FIG. tP
The straight line distance fidl- from to the position of each vibration sensor 6
d3 can be obtained.

Furthermore, the coordinates (x, y) of the position P of the vibrating pen 3 can be determined by the arithmetic and control circuit 1 based on the straight line distance fid, 1-d3 as shown in the following equation using the 3-square theorem.

x=X/2+ (dl+d2)(di-d2)/2X・
...(4) y=Y/2+ (d 1 + d3) (d 1 - d3)/
2Y (5) Here, x and Y are the distances along the x and Y axes between the vibration sensor 6 at the positions S2 and S3 and the sensor at the origin (position s1).

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

Next, in the above configuration, a correction process for removing the effects of the circuit delay time et and the phase offset time tof in the calculation of the pen-sensor distance and coordinate determination described above will be described.

The vibration transmission time latched by the latch circuit 14 includes a one-circuit delay time et and a phase offset time tof. Errors caused by these factors are always the same when the vibration is transmitted from the vibrating pen 3 to the vibration transmitting plate 8 and the vibration sensor 6.

Therefore, for example, let R be the distance from position n of the mark 8a in FIG.
'r, and if the true transmission time from the mark 8a to the sensor is tgr, tpr, then these are the circuit delay times et
and phase offset tof tg'r=tgr+et...(6)
t p ′r=t gr+et+t of −・
- There is a relationship as shown in (7).

On the other hand, the actual measured values tg'p and tp'p at any input point P
Similarly, tg'P=tgP+et...(8)
tp'p=t-pp+et+tof,,,(9
), and finding the difference between the two, we get tg ′p-tg ′r=(tgp+et)-(tgr
+et)=tgp-tgr,=・(10)tp′p
−tp ′r=(tpp+et+tof)−(tpr+
et+tof)”tpp-tpr
...(11), the circuit delay time et and phase offset (tof) included between each transmission plane are removed, and the true value is calculated according to the distance from the position of the mark 8a to the sensor position between the human power point P. The difference in vibration transmission time can be found.

The distance difference between the two points can be obtained by using the above-mentioned equations (2) and (3) for the time difference value, and the distance R from the mark 8a to the sensor is stored in the ROM 11a in advance and is known. Therefore, by calculating the sum of these, the distance between the input point and the sensor can be determined, and furthermore, the above (4),
The coordinate position can be determined by calculating equation (5).

Correction value tg'r due to vibration input to the position of mark 8a,
tp'r may be acquired at a predetermined timing, for example, immediately after power is turned on, by displaying a message on the display 11' to prompt the operator, or the correction value may be acquired at predetermined intervals during operation. You may do so. The acquired correction value may be stored in RAM Ib.

By always performing two-legged correction during operation, changes in circuit delay time and the like caused by environmental changes can be appropriately corrected. However, a system in which correction values are taken in at the time of factory shipment and the data is stored in a non-volatile memory or the like can also appropriately correct at least circuit delays and phase offsets that vary from device to device.

In the embodiment described above, it is necessary to measure the delay time at the known position of the mark 8a, and the operator is required to input coordinates accurately to the position of the mark 8a. However, by using the following method, it is possible to input coordinates for inputting correction values at any position.

That is, the coordinates are determined from the hyperbolic function using the delay time difference between the sensors, and the delay time is corrected from the determined value.

Coordinate determination based on the delay time difference can be accomplished by, for example, assuming that the sensors are arranged as shown in Figure 8 and the intersection point 0 of the straight lines connecting the opposing sensors is set as the origin, the difference in distance between the sensors SO and S1 is a, S2
If the difference in distance between and 53 is b, then the indicated point P(x, y)
is obtained as the intersection of hyperbolic functions as shown in the following equation.

However, c2=4X2-a2. d2=4Y2-b2. c2
d2-a2b2〉0 The coordinates of any input point can be determined by these equations.

At this time, the vibration transmission time to each sensor is set as the correction value RA.
If stored in MI Ib, the above correction process can be performed.

According to such a method, since it is possible to obtain a correction value at an arbitrary position, even a user can easily perform correction. In addition, if this operation is performed periodically or irregularly at fixed time intervals (for example, when specifying an arbitrary area while inputting coordinates), the correction value can be automatically imported without the user being aware of it. Can be done. Furthermore, it is possible to completely correct changes in circuit delay time due to temperature changes and the like.

However, as can be seen from equations (12) and (13), the calculations using a microprocessor are extremely complex, so in terms of accuracy and calculation speed, the above method is not suitable for real-time coordinate determination. method is more advantageous.

However, when a correction value is taken in as in this embodiment, there is not much time limit and the number of digits in calculation can be increased, so it can be used sufficiently for coordinate determination.

It goes without saying that even with the sensor arrangement as shown in FIG. 7, the coordinates can be determined using the Mikata theorem as described above.

In the embodiments described below, a manual coordinate input device using plate waves has been mainly described, but the configuration of the present invention is not limited to this, and can be applied to various coordinate input devices using vibration transmission as a medium. Needless to say, it is.

[Effects of the Invention] As is clear from the following, according to the present invention, vibrations manually applied from a vibrating pen are detected by a plurality of vibration sensors provided on the vibration transmitting plate, and the vibrations are transmitted on the vibration transmitting plate of the vibrating pen. A coordinate input device for detecting the coordinates at is used, and a predetermined calculation method is used based on the vibration transmission period 11+j of the vibration input from an arbitrary manual point on the vibration transmission plate to each vibration sensor and the vibration transmission time. means for storing the coordinates of the arbitrary input point as a correction value; and measuring the vibration transmission time from the coordinate input point by the vibrating pen to each vibration sensor described in 1ih,
The correction value of the vibration transmission time stored in the storage means is subtracted from this full planting, and the vibration transmission time corresponding to the distance from the arbitrary input point to the human power point is calculated. The control means performs coordinate calculation based on the memorized coordinate values of any human power point.Since it has a sophisticated configuration, the vibration transmission time corresponding to the distance from any input point to the coordinate human power point can be calculated. By subtracting the circuit delay time and phase offset time by subtraction, it is possible to obtain accurate coordinate values regardless of the term boundary conditions. In addition, if normal coordinate input is handled as coordinate input to the above-mentioned arbitrary point, there is an excellent effect that correction can be performed automatically without requiring a troublesome correction value input operation.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the configuration of an information input/output device adopting the present invention, Fig. 2 is an explanatory diagram showing the structure of the vibrating pen shown in Fig. 1, and Fig. 3 is an explanatory diagram showing the structure of the vibrating pen shown in Fig. 1. Figure 4 is a waveform diagram showing the detected waveform to explain distance # measurement between the vibrating pen and the vibration sensor, and Figure 5 shows the configuration of the waveform detection circuit in Figure 1. Block diagram, Fig. 6 is an explanatory diagram showing the arrangement of vibration sensors, Fig. 7 is an explanatory diagram showing the sensor arrangement in different embodiments, and Fig. 8 is a diagram showing problems with the conventional coordinate input device. It is. ■... Arithmetic control circuit 3... Vibration pen 4... Vibrator 6... Vibration sensor 8... Vibration transmission plate 8a... Mark 11... Microcomputer 11 a... ROM l l b...-RAM
(Detection U3m) Arithmetic system theft? 77 diagrams of each arrow Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1) A coordinate input device that detects the coordinates of the vibrating pen on the vibration transmitting plate by detecting the vibration input from the vibrating pen using a plurality of vibration sensors provided on the vibration transmitting plate, Means for storing the coordinates of the arbitrary input point as a correction value using a predetermined calculation method based on the vibration transmission time of the vibration input from an arbitrary input point on the vibration transmission plate to each of the vibration sensors and the vibration transmission time. and measuring the vibration transmission time from the coordinate input point by the vibrating pen to each of the vibration sensors,
The correction value of the vibration transmission time stored in the storage means is subtracted from this measured value to calculate the vibration transmission time corresponding to the distance from the arbitrary input point to the coordinate input point. A coordinate input device characterized by comprising a control means for performing coordinate calculation based on coordinate values of an arbitrary input point. 2) Treat the coordinate input performed during the input process as a coordinate input to the arbitrary input point, and import the vibration transmission time and the coordinates of the input point as correction values, and use the coordinate input from other input points as correction values. The coordinate input device according to claim 1, which is used for correction.