JPH06161641A - Coordinate input device - Google Patents

Abstract

PURPOSE:To provide a coordinate input device which prevents unnecessary input and is excellent in operability. CONSTITUTION:When vibration is imparted to a vibration transmission plate by a vibration pen, signals from four sensors on the transmission plate are inputted in an input circuit 35. These signals are inputted in a decision circuit 36 and a latch circuit 34, and the decision circuit 36 decides that vibration is inputted and inputs a detection signal in a microcomputer 31. The microcomputer 31 calculates coordinates based on the vibration delay time sensed by each sensor latched to a latch circuit when the detection signal is inputted. The microcomputer 31 reads the state of a switch 38, neglects the detection signal of the decision circuit if the switch is an ON-state and inputs the effect that coordinate inputs are not performed with calculated coordinate value in an IO port 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device, and in particular, elastic wave vibration input from a vibrating pen is detected by a plurality of sensors provided on the vibration transmitting plate, and elasticity input from the vibrating pen to the vibration transmitting plate is detected. The present invention relates to a coordinate input device that detects the coordinates of a vibration input point by a vibration pen based on the transmission time of wave vibration.

[0002]

2. Description of the Related Art An ultrasonic coordinate input device is a method of calculating a position coordinate by detecting a delay time of a wave propagating on a tablet which is an input surface. Since it is not applied at all, it is possible to provide an inexpensive device. Moreover, if a transparent plate glass is used for the tablet, it is possible to configure a coordinate input device having higher transparency than other methods.

In such a coordinate input device utilizing ultrasonic waves, when the wavelength of the elastic wave propagating on the vibration transmitting plate becomes larger than the plate thickness of the plate, plate waves having different group velocities and phase velocities propagate. Is well known. When this wave is used, the point where the phase propagation delay time is detected is the point where the elastic wave is above a certain level, and the point where the group delay time is detected is the peak of the envelope of the detected signal waveform, and the distance and wave The relationship between the arrival delay times is schematically shown in FIG. The group delay time tg shows a relationship that is continuous but has a large fluctuation width, and the phase delay time tp shows a stepwise relationship. This relationship is caused by the nature of the plate wave in which the phase velocity and the group velocity are different. At this time, it is impossible to accurately measure the distance only by the group delay time tg, and when the distance is calculated only by the phase delay time tp,
Even if the influence of sound wave attenuation and writing pressure dependency is removed by electrically setting the level of the detection signal waveform to be electrically constant, FIG.
The relationship between the phase delay time and the distance as shown in (3) remains stepwise, and when the delay time of ta is output in the figure, there is a disadvantage that it is not possible to determine whether the distance is L1 or L2. .

To solve this problem, a method has been proposed in which both the group delay time and the phase delay time of the plate wave are detected to calculate the coordinates. This method is d = Vp · Tp + n · λp (1) n = int [(Vg · Tg−Vp · Tp) / λp + 1 / N] (2) when the distance between the sensor and the vibration input source is d. ) Vp: Phase velocity of plate wave, Tp: Phase delay time Vg: Group velocity of plate wave, Tg: Group delay time λp: Wavelength of plate wave The distance to each sensor is calculated and geometrically calculated from this information. The coordinates are calculated. This method can calculate the coordinates by using the plate wave without depending on the level of the detection signal waveform, and further, by utilizing the transparency to integrate the coordinates with the display device, An integrated device can be constructed.

[0005]

In the coordinate input device (input / output integrated type device) as described above, there is a prescribed rule that signals that have been propagated by a plurality of detecting means (sensors) are input. It was judged that it was detected at a certain level or higher within the time. Alternatively, the pen tip is provided with a switch means, and the up / down of the pen, that is, the input is determined by turning the switch on / off.

For example, when the coordinate value is transferred to an external device and the writing locus is displayed on the display device, when transmitting the coordinate value, a flag indicating whether the pen-up state is the pen-down state is transmitted at the same time, and the actual The display is close to the writing state.

In the case of operating various applications using such an input / output integrated device, for example, there is a case where a pen is used to point and explain a displayed graph or the like. In such a case, there is an inconvenience that extra coordinate input is made every time the pen contacts the input surface, data is destroyed, and unnecessary input is made.

Further, in an application that requires input in a very small area, there is a problem that input is made in an incorrect position due to the influence of parallax or the like. The present invention has been made in view of the above conventional example, and an object of the present invention is to provide a coordinate input device which prevents unnecessary input and has good operability.

[0009]

In order to solve the above problems, the coordinate input device of the present invention has the following configuration.

Based on the instruction means for instructing the coordinate position, the determination means for determining whether or not the coordinate position is instructed by the instruction means, the selection means for selecting the mode, and the mode selected by the selection means. A changing unit that changes the determination result by the determining unit and a unit that outputs the change result by the changing unit are provided.

[0011]

With the above construction, when the coordinate input is performed by the instructing means, it is determined that the coordinate input is performed, but the determination result is changed and output according to the selected mode.

[0012]

1 shows the structure of a coordinate input device according to an embodiment of the present invention. In the figure, reference numeral 1 denotes an arithmetic control circuit for controlling the entire apparatus and calculating a coordinate position. Reference numeral 2 denotes a vibrator drive circuit for vibrating the pen tip inside the vibrating pen 3. Reference numeral 8 is a vibration transmitting plate which is a vibration propagating body made of a transparent member such as acrylic or glass plate, and the coordinate input by the vibrating pen 3 is performed by touching the vibration transmitting plate 8. In practice, the vibrating pen 3 is used to designate the area within the area A (hereinafter referred to as the effective area) indicated by the solid line in the figure. Further, on the outer periphery of the vibration transmission plate 8, a vibration isolator 7 is provided for preventing (reducing) the reflected vibration from returning to the central portion, and as shown in FIG. Further, vibration sensors 6a to 6d, such as piezoelectric elements, which convert mechanical vibrations into electric signals are fixed.

Reference numeral 9 is a signal waveform detection circuit for outputting to the arithmetic and control circuit 1 a signal in which vibration is detected by each of the vibration sensors 6a to 6d. Reference numeral 11 is a display such as a liquid crystal display capable of displaying in dot units, and is arranged behind the vibration transmission plate. Then, by driving the display drive circuit 10, it is possible to display a dot at a position traced by the vibrating pen 3 and see it through the vibration transmission plate 8 (made of a transparent member). Vibrator 4 built in the vibration pen 3
Are driven by the oscillator drive circuit 2. The drive signal for the vibrator 4 is supplied as a low-level pulse signal from the arithmetic control circuit 1, amplified by a predetermined gain by the vibrator drive circuit 2, and then applied to the vibrator 4.

The electric drive signal is converted into mechanical vibration by the vibrator 4 and transmitted to the vibration transmission plate 8 via the pen tip 5.

Here, the vibration frequency of the vibrator 4 is selected to a value capable of generating a plate wave on the vibration transmission plate 8 such as glass. Further, when driving the vibrator, a mode in which the vibration transmitting plate 8 vibrates in the vertical direction of FIG. 2 is selected. Also,
By setting the vibration frequency of the vibrator 4 to the resonance frequency including the pen tip 5, efficient vibration conversion can be performed.

The elastic wave transmitted to the vibration transmission plate 8 as described above is a plate wave, and has an advantage that it is less susceptible to scratches and obstacles on the surface of the vibration transmission plate as compared with surface waves. .

<Description of Arithmetic and Control Circuit> In the above-mentioned configuration, the arithmetic and control circuit 1 has a predetermined cycle (for example, every 5 ms).
Then, a signal for driving the vibrator driving circuit 2 and the vibrator 4 in the vibrating pen 3 is output, and the internal timer (made up of a counter) starts timing. And
The vibration generated by the vibrating pen 3 propagates on the vibration transmission plate 8 and arrives with a delay depending on the distance to the vibration sensors 6a to 6d.

The signal waveform detection circuit 9 includes the vibration sensors 6a to 6a.
The signal from 6d is detected, and a signal indicating the vibration arrival timing to each vibration sensor is generated by the waveform detection processing described later. This signal for each sensor is input to the arithmetic control circuit 1, and each vibration is input. The vibration arrival time to the sensors 6a to 6d is detected, and the coordinate position of the vibrating pen is calculated.

Further, the arithmetic control circuit 1 drives the display drive circuit 10 based on the calculated position information of the vibrating pen 3 to control the display by the display 11.
Alternatively, coordinates are output to an external device by serial or parallel communication (not shown). FIG. 3 is a block diagram showing a schematic configuration of the arithmetic control circuit 1 of the embodiment, and each component and its operation outline will be described below.

In the figure, reference numeral 31 is a microcomputer for controlling the arithmetic control circuit 1 and the coordinate input apparatus as a whole, and an internal counter, a ROM storing operation procedures, a RAM used for calculations and the like, and a nonvolatile memory storing constants and the like. It is composed of a sex memory.

Reference numeral 33 is a timer (not shown) for counting a reference clock, which is a start for causing the vibrator drive circuit 2 to start driving the vibrator 4 in the vibrator pen 3. When a signal is input, the timing starts. As a result, the start of timing and the vibration detection by the sensor are synchronized, and the delay time until the vibration is detected by the sensors (6a to 6d) can be measured.

The other circuits constituting the respective components will be described in order.

The vibration arrival timing signals from the vibration sensors 6a to 6d output from the signal waveform detection circuit 9 are latched through the detection signal input port 35 to the latch circuits 34a to 34a.
It is input to d. Each of the latch circuits 34a to 34d corresponds to each of the vibration sensors 6a to 6d, and when receiving a timing signal from the corresponding sensor, it latches the measured value of the timer 33 at that time. When the determination circuit 36 determines that all the detection signals have been received,
A signal to that effect is output to the micro computer 31.
Microcomputer 31 outputs this output and switch 38.
The new coordinates are calculated by inputting the state of and.

The switch 38 is a switch for switching the coordinate input mode between the input mode and the non-input mode, and its state is held as a pen state flag. The microcomputer 31 determines that coordinate input has been made based on the output of the determination circuit 36 and the input from the switch 38. For this determination, for example, if there is an input from the determination circuit 36 and the switch 38 is not ON, the pen state is determined to be pen down. Also, the determination circuit 3
If the switch 38 is off even if there is an input from 6, it is determined that the pen state is pen-up. As described above, the pen state is determined by giving priority to the switch 38, but the calculation of the coordinate value follows the input of the determination circuit 36.

That is, when the microcomputer 31 receives the signal from the determination circuit 36, the latch circuit 34a
The vibration arrival time from 34d to each vibration sensor is read from the latch circuit and a predetermined calculation is performed to calculate the coordinate position of the vibration pen 3 on the vibration transmission plate 8. And I
By outputting the calculated coordinate position information and the pen down to the display drive circuit 10 via the / O port 37, for example, a dot or the like can be displayed at the corresponding position on the display 11. Alternatively, the coordinate value can be output to an external device by outputting the coordinate position information and the pen state information to the interface circuit via the I / O port 37. As described above, the pen state information is information obtained based on the inputs from the determination circuit 36 and the switch 38, and the coordinate information is a value calculated based on the inputs of the determination circuit 36 and the latch circuit 34. Information that can be obtained independently.

In a normal coordinate input operation, when the pen 3 comes into contact with the input surface and input is performed, the microcomputer 31 determines that the pen 3 is in the pen-down state and the instructed coordinate information and the pen-down state. Output status information and. When the operator does not want the normal coordinate input, the operator presses the switch 38 to switch to the non-input mode. When coordinates are input in the non-input mode, coordinates are calculated because the output of the determination circuit 36 is pen-down, but the pen status information is in the pen-up status according to the switch 38, together with the coordinate information instructed by the pen. The pen status information indicating the pen up is output to the IO port 37.

In the pen-up state in normal operation,
The microcomputer 31 does not output coordinates, since it has not entered a pen, and outputs pen-up as pen state information. Alternatively, the coordinate value peculiar to the pen-up is output together with the pen-up. Thus in normal operation,
Despite being in the pen-down state, it outputs the pen-up as the pen-state information according to the state of the switch 38 to prevent inadvertent input, and further, to switch the cursor etc. like a mouse-compatible application. By displaying by pressing, it becomes possible to input a pull-down menu or a detailed portion without erroneous input due to parallax or the like.

<Description of Vibration Propagation Time Detection (FIGS. 4 and 5)
> Hereinafter, the principle of measuring the vibration arrival time to the vibration sensor 3 will be described.

FIG. 4 is a diagram for explaining a detection waveform input to the signal waveform detection circuit 9 and a vibration transmission time measuring process based on the detection waveform. The vibration sensor 6a will be described below, but the other vibration sensors 6b, 6c, 6
The same is true for d.

It has already been described that the measurement of the vibration transmission time to the vibration sensor 6a is started at the same time as the output of the start signal to the vibrator drive circuit 2. At this time, the drive signal 41 is applied from the vibrator drive circuit 2 to the vibrator 4. The ultrasonic vibration transmitted from the vibration pen 3 to the vibration transmission plate 8 by the signal 41 progresses for a time tg corresponding to the distance to the vibration sensor 6a, and then is detected by the vibration sensor 6a.

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

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

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

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

FIG. 5 is a block diagram showing the configuration of the signal waveform detection circuit 9 of the embodiment. In FIG. 5, the vibration sensor 6
The output signal a is amplified by the preamplifier circuit 51 to a predetermined level. The bandpass filter 511 removes extra frequency components of the detection signal from the amplified signal, and the amplified signal is input to an envelope detection circuit 52 including, for example, an absolute value circuit and a low-pass filter. Only is taken out. The timing of the envelope peak is detected by the envelope peak detection circuit 53. The peak detection circuit is a signal t which is an envelope delay time detection signal of a predetermined waveform by a tg signal detection circuit 54 composed of a mono multivibrator or the like.
g (signal 43 in FIG. 4) is formed and input to the arithmetic control circuit 1. On the other hand, 55 is a signal detection circuit, which forms a pulse signal 47 of a portion of the envelope signal 421 detected by the envelope detection circuit 52 that exceeds the threshold signal 46 of a predetermined level. 56 is a monostable multivibrator, which opens the gate signal 44 of a predetermined time width triggered by the first rising edge of the pulse signal 47. Reference numeral 57 denotes a tp comparator, which detects a zero-crossing point of the first rising edge of the phase signal 422 while the gate signal 44 is open,
The phase delay time signal tp45 is supplied to the arithmetic control circuit 1. The circuit described above is for the vibration sensor 6a, and the same circuit is provided for other vibration sensors.

<Description of Delay Time Correction> The vibration transmission time latched by the latch circuit is the circuit delay time et.
And the phase offset time toff. The error caused by these is always included in the same amount when the vibration is transmitted from the vibration pen 3 to the vibration transmission plate 8 and the vibration sensors 6a to 6d.

Therefore, for example, from the position of the origin O in FIG.
For example, the distance to the vibration sensor 6a is R1 (= X / 2; X
Is the distance between the sensors 6a and 6b), and the measured vibration transmission time from the origin O to the sensor 6a measured by inputting with the vibrating pen 3 at the origin O is tgz ', tpz' and from the origin O to the sensor. Let tgz and tpz be the true propagation times of Tgz, tpz, and Tgz ′ = tgz + et (4) tpz ′ = tpz + et + toff (5) with respect to the intrinsic delay time et and the phase offset toff.

On the other hand, the measured value t at an arbitrary input point P
Similarly, g ′ and tp ′ are tg ′ = tg + et (6) and tp ′ = tp + et + toff (7). When the difference between these (4), (6), (5) and (7) is obtained, tg'-tgz '= (tg + et)-(tgz + et) = tg-tgz (8) tp'-tpz' = (tp ' + Et + toff)-(tpz + et + toff) = tp-tpz (9), the circuit delay time et and the phase offset toff included in each transmission time are removed, and the position of the sensor 6a between the position of the origin O and the input point P is set as the starting point. The difference in the true transmission delay time according to the distance can be obtained, and the distance difference can be obtained by using the equations (1) and (2). Since the distance from the vibration sensor 6a to the origin O is stored in advance in a non-volatile memory or the like and is known, the distance between the vibration pen 3 and the vibration sensor 6a can be determined. The other sensors 6b to 6d can be similarly obtained.

The measured values tgz 'and tpz' at the origin O are stored in the nonvolatile memory in advance,
The equations (8) and (9) are executed before the calculation of the equations (1) and (2), and highly accurate measurement can be performed.

<Description of Coordinate Position Calculation (FIG. 6)> Next, the principle of actually detecting the coordinate position on the vibration transmission plate 8 by the vibration pen 3 will be described.

Now, in the vicinity of the midpoint of four sides on the vibration transmission plate 8,
When the two vibration sensors 6a to 6d are provided at the positions S1 to S4, the linear distances da to dd from the position P of the vibrating pen 3 to the positions of the respective vibration sensors 6a to 6d are calculated based on the principle described above. You can ask. Further, the arithmetic control circuit 1 can obtain it based on the linear distances da to dd from the theorem of 3 squares of the coordinates (x, y) of the position P of the vibrating pen 3 as follows.

X = (da + db) · (da−db) / 2X (10) y = (dc + dd) · (dc−dd) / 2Y (11) or x = (dc + dd) · (dc−dd) / 2X (10) ′ y = (db + dd) · (db−dd) / 2Y (11) ′ Here, X and Y are the distance between the vibration sensors 6a and 6b (or between 6c and 6d) and the vibration sensors 6a and 6c, respectively. (Or between 6b and 6d).

As described above, the position coordinates of the vibrating pen 3 can be detected in real time, and the pen status information is output together with the coordinate position information on the basis of the switch 38. It is possible to prevent input of coordinates.

In this embodiment, the switch 38
As the switch means, which is turned on only when pressed, is used, but a switch means that is switched on / off each time the button is pressed may be used. This makes it easy to continue a mode that has not been input for a long time. These switch means may be installed on the main body or may be attached to the pen.

Alternatively, the mode may be switched by providing an area such as a menu on the display screen and instructing the area without using a mechanical or electrical hardware switch. In the normal coordinate input valid area, the operation determined by judging that the area is selected by the value of the pen status information is performed, but in this menu area,
Regardless of the pen status information, when the coordinates in the menu area are obtained, the mode is changed according to the menu. With this configuration, it is possible to change the pen up / down information by software.

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

[0047]

As described above, the coordinate input device according to the present invention has the effects of preventing unnecessary input and improving operability.

[Brief description of drawings]

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

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

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

FIG. 4 is a timing chart of signal processing.

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

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

FIG. 7 is a diagram illustrating a relationship between a phase delay time / group delay time of a plate wave and a transmission distance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Arithmetic control circuit, 2 ... Oscillator drive circuit, 3 ... Vibration pen, 6 ... Sensor, 7 ... Antivibration material, 8 ... Vibration transmission plate, 9 ... Signal waveform detection circuit, 38 ... Pen up / down switch.

Front page continued (72) Inventor Katsuyuki Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masaki Tokioka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Ryozo Yanagisawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (5)

[Claims] 1. An instructing means for instructing a coordinate position, a determining means for determining whether or not the coordinate position is instructed by the instructing means, a selecting means for selecting a mode, and a mode selected by the selecting means. A coordinate input device comprising: a changing unit that changes the determination result by the determining unit based on the changing unit; and a unit that outputs the change result by the changing unit. 2. When the predetermined mode is selected by the selecting means, the changing means changes the determination result by the determining means to that the coordinate position is not instructed, and the other mode. The coordinate input device according to claim 1, wherein the determination result is not changed in a case. 3. The instructing means has a vibration source means for generating vibration and a vibration transmitting plate, and the vibration source means points on the vibration transmitting plate to input coordinates and detect the position of the vibration source. The coordinate input device according to claim 1, wherein the coordinate is calculated according to the following equation. 4. The coordinate input device according to claim 1, wherein the selection means is a switch, and selects the mode according to a state of the switch. 5. The coordinate input device according to claim 1, wherein the selecting means selects a mode based on an instruction of the coordinate position by the instructing means.