JP2524614B2 - Coordinate input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention detects a vibration input from a coordinate input device, particularly a vibration pen, by using a plurality of sensors provided on the vibration transmission plate, and transmits the vibration to the vibration transmission plate of the vibration pen. The present invention relates to a coordinate input device for detecting the above coordinates.

2. Description of the Related Art Conventionally, coordinate input devices using various input pens, tablets, and the like have been known as devices for inputting handwritten characters, graphics, and the like to a processing device such as a computer.
In this type of system, input image information including characters, figures, and the like is output to a display device such as a CRT display or a recording device such as a printer.

The following various methods are known for detecting the coordinates of a tablet of this type of device.

1) A method of detecting a change in resistance value of a sheet material disposed opposite to a resistance film.

2) A method of detecting electromagnetic or electrostatic induction of a conductive sheet or the like arranged opposite to each other.

3) A method of detecting ultrasonic vibration transmitted from the input pen to the tablet.

In the above methods 1) and 2), it is difficult to form a transparent tablet because a resistance film or a conductor film is used. On the other hand, in the method of 3), the tablet can be made of a transparent material such as an acrylic plate or a glass plate, so that the input tablet can be placed on a liquid crystal display, etc., and used as if writing an image on paper. A good information input / output device can be configured.

[Problems to be Solved by the Invention] A conventional coordinate input device using elastic waves uses a vibrating pen for inputting vibration to a vibration transmission plate. A vibrator including a piezoelectric element is built in the vibrating pen. The vibration of the vibrator is input to the vibration transmission plate via a vibration input member having a horn shape for amplifying the vibration.

Since this vibration input member is operated directly in contact with the vibration transmission plate, it wears and wears during long-term use. When the shape of the vibration input member changes due to wear or the like, the shape of the horn changes, its vibration transmission characteristics change, and it becomes impossible to obtain sufficient vibration input strength, resulting in a decrease in coordinate detection accuracy or incomplete input. The problem arises that it will be possible.
Further, there is a problem that the input accuracy becomes unstable due to the influence of the tilt of the pen and the pen pressure on the input vibration due to the shape change of the input member.

Therefore, a structure in which the vibration input member of the pen tip is made replaceable is conceivable, but in this structure, the vibrator coupled with this when the vibration input member is removed is exposed,
An operator carelessly touches the vibrator to impair its characteristics, or drops and damages the vibrator inside when replacing the pen tip,
There is a risk of electric shock by touching the vibrator while driving the vibrator.

An object of the present invention is to solve such a problem.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, the vibration input from the vibrating pen is detected by a plurality of sensors provided on the vibration transmitting plate to transmit the vibration of the vibrating pen. In a coordinate input device for detecting coordinates on a plate, a vibrator arranged inside the vibrating pen, a vibration input member detachably provided at the tip of the vibrating pen, and a vibration generated by the vibrator are described above. A structure is adopted in which an insulation protection member is provided for transmitting to the vibration input member, electrically insulating between the vibrator and the vibration input member, and protecting the inside of the pen at a portion opened when the vibration input member is detached. .

[Operation] According to the above configuration, when the vibration input member is removed, the vibrator is insulated from the outside by the protection member, so that the operator carelessly touches the vibrator and hinders its characteristics.
Alternatively, there is no danger of being touched by the vibrator while being driven and receiving an electric shock.

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

FIG. 1 shows the structure of an information input / output device adopting the present invention. The information input / output device of FIG. 1 causes the input tablet composed of the vibration transmission plate 8 to input coordinates by the vibrating pen 3, and the display device 11 'composed of a CRT arranged on the input tablet according to the input coordinate information. The input image is displayed on.

The reference numeral 8 in the drawing denotes a vibration transmission plate made of acrylic, glass plate or the like, which transmits vibration transmitted from the vibration pen 3 to three vibration sensors 6 provided at the corners. In this embodiment, the coordinate of the vibration pen 3 on the vibration transmission plate 8 is detected by measuring the transmission time of the ultrasonic vibration transmitted from the vibration pen 3 to the vibration sensor 6 via the vibration transmission plate 8.

The vibration transmitting plate 8 has its peripheral portion supported by an antireflection material 7 made of silicon rubber or the like in order to prevent the vibration transmitted from the vibrating pen 3 from being reflected at the peripheral portion and returning toward the central portion. ing.

The vibration transmitting plate 8 is arranged on a display device 11 'capable of displaying dots, such as a CRT (or a liquid crystal display device), and displays dots at the position traced by the vibration pen 3. That is, a dot display is performed at a position on the display 11 ′ corresponding to the detected coordinates of the vibrating pen 3, and the image composed of elements such as points and lines input by the vibrating pen 3 is written on paper. Appears after the locus of the vibrating pen as you did.

Further, according to such a configuration, a menu is displayed on the display 11 ', and the vibrating pen is used to select the menu item, or a prompt is displayed to bring the vibrating pen 3 into contact with a predetermined position. Can also be used.

Vibration pen 3 for transmitting ultrasonic vibrations to the vibration transmission plate 8
Has an oscillator 4 formed of a piezoelectric element or the like inside, and transmits the ultrasonic vibration generated by the oscillator 4 to the vibration transmission plate 8 via the horn portion 5 having a sharp tip.

FIG. 2A shows the structure of the vibrating pen 3. The vibrator 4 built in the vibrating pen 3 is driven by the 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 in FIG. 1, amplified by a predetermined gain by the vibrator drive circuit 2 capable of low impedance driving, and then the vibrator 4 Applied to.

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

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 acrylic or glass. Further, when driving the vibrator, the second
A vibration mode is selected in which the vibrator 4 mainly vibrates in the vertical direction of FIG. Further, by setting the vibration frequency of the vibrator 4 as the resonance frequency of the vibrator 4, it is possible to perform efficient vibration conversion.

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

FIG. 2B shows the structure of the tip of the vibrating pen 3 in detail.

The vibrator 4 used in this embodiment is a cylindrical piezoelectric element, and polarization is performed inside and outside the cylinder, and the piezoelectric lateral direction is used (the applied electric field direction and the displacement direction are at right angles).

 Of course, other types of piezoelectric elements may be used.

In the figure, reference numeral 25 is a pen shaft which supports the horn 5 and constitutes a coordinate input pen main body, reference numeral 24 is a positioning member which positions the outer electrode 23 and the inner electrode 21 with respect to the vibrator 4, and the outer periphery thereof is In the case of this embodiment, it is engaged with the pen shaft 25 and also serves as a positioning member for the vibrator 4.

Reference numeral 22 is a drive electrode which is in contact with the outer electrode 23 having a spring member 23 'by a coil spring, and the vibrator 4 is crimped to the horn 5 together with the spring portion 21' of the inner electrode 21 which is also a concentric coil spring. . Further, the horn 5 and the pen shaft 25 are fixed via screw portions 26, respectively.

With such a structure, the horn 5 can be easily detached from the pen shaft 25 when abrasion occurs.
It can be easily replaced by the user. Therefore, by exchanging the horn 5, the initial vibration input performance can be maintained, and problems such as inability to input coordinates or reduction in input accuracy do not occur.

Further, in this embodiment, as shown in FIG. 2B, the horn 5 and the pen shaft 25 are fixed by using the screw portion 26.
Any structure may be adopted as long as it is a method or means that can be easily removed by the user without using a tool.

As the structure of the tip of the vibrating pen 3, FIG.
A structure as shown in (D) can also be used.

In FIG. 2 (C), an insulating protection member 27 is provided to prevent the vibrator 4 from falling when the horn 5 is removed or to prevent the user from directly touching the vibrator 4 or the inner and outer electrodes 21 and 23. Is provided between the vibrator 4 and the screw portion 26.

The insulating protection member 27 is fixed to the pen shaft 25 by means such as adhesion or welding. Further, at least the side in contact with the horn 5 is insulated, and no current flows directly to the user even when power is being supplied. The material is not an insulating material (such as polyimide) through which ultrasonic vibration propagates, or a metal having an insulating layer. Also, horn 5
Is fixed to the pen shaft 25 with a screw portion 26.

Further, grease or the like may be filled between the insulating protection member 27, the horn 5, and the vibrator 4 in order to increase the vibration propagation efficiency. In experiments, it has been found that the filling of grease or the like allows stable vibration transmission between the two media.

With such a structure, even if the horn 5 is removed during replacement, the vibrator 4 is not exposed, and the vibrator 4 is prevented from being dropped or being inadvertently touched and damaged. Further, the insulating protection member 27 serves to insulate the vibrator 4
It is also possible to avoid the risk of touching the vibrator 4 and being electrically shocked while the drive current is being applied to.

In the structure of FIG. 2 (D), the screw portion 26 is attached to the insulation protection member 27 '.
Is provided, and the horn 5 is screwed to the screw portion 26. According to this structure, the screw portion 26 is an insulating protection member.
Since it can be formed integrally with 27, the manufacturing process can be simplified.

Again, in FIG. 1, the vibration sensor 6 provided at the corner of the vibration transmission plate 8 is also composed of a mechanical-electrical conversion element such as a piezoelectric element. The output signals of each of the three vibration sensors 6 are input to the waveform detection circuit 6, and the arithmetic control circuit 1 in the subsequent stage
Is converted into a processable detection signal. The arithmetic control circuit 1 performs the measurement process of 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 vibrating pen 3 is processed in the arithmetic and control circuit 1 according to the output system 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 1 of FIG. Here, the structure of the drive system of the vibration pen 3 and the vibration detection system by the vibration sensor 6 is mainly shown.

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

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

On the other hand, the waveform detection circuit 9 outputs timing information of the detection signal for measuring the vibration transmission time for coordinate detection from the 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 each of the vibration sensors 6 in the latch circuit 14
Is stored in the storage area corresponding to the result of the calculation, 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 the coordinate calculation is performed based on this vibration transmission time value. At this time, the determination circuit 16 determines whether or not all the waveform detection timing information from the plurality of vibration sensors 6 has been input, and notifies the microcomputer 11 of this.

The output control processing of the display 11 'is performed via the input / output port 17.

FIG. 4 illustrates a detection waveform input to the waveform detection circuit 9 shown in FIG. 1 and a vibration transmission time measurement process based on the detection waveform. In FIG. 4, reference numeral 41 denotes 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 inside of the vibration transmission plate 8 and is detected by the vibration sensor 6.

After traveling within the vibration transmission plate 8 for a time tg corresponding to the distance 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, 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 speed at which the envelope advances is defined as the group speed Vg, and the phase speed is defined as Vp. The distance between the vibration pen 3 and the vibration sensor 6 can be detected from the difference between the group velocity and the phase velocity.

First, focusing only on the envelope 421, its speed is Vg, and when a point on a certain specific waveform, for example, a peak is detected as indicated by reference numeral 43 in FIG. 4, the distance between the vibrating pen 3 and the vibration sensor 6 is detected. d is the vibration transmission time tg, d = Vg · tg (1) This formula relates to one of the vibration sensors 6,
The distance between the other two vibration sensors 6 and the vibration pen 3 can be indicated by the same equation.

Further, in order to determine the coordinate value with higher accuracy, processing based on the detection of the phase signal is performed. Phase waveform of Fig. 4
If the time from the specific detection point of 422, for example, the application of vibration to the zero crossing point after passing the peak is tp, the distance between the vibration sensor and the vibration pen is d = n · λp + Vp · tp (2). Here, λp is the wavelength of the elastic wave, and n is an integer.

From the above equations (1) and (2), the integer n is expressed as follows: n = [(Vg · tg−Vp · tp) / λp + 1 / N] (3) Here, N is a real number other than 0, and an appropriate value is used. For example, if N = 2 and n is within ± 1/2 wavelength, n can be determined.

The distance between the vibration pen 3 and the vibration sensor 6 can be accurately measured by substituting n obtained as described above into the expression (2).

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 above-mentioned amplifier circuit 51.

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 input to the arithmetic control circuit 1.

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

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

That is, the monostable multivibrator 55 and the comparator level supply circuit 56 are for allowing the measurement of the phase delay time to operate only for a fixed time after the envelope peak is detected.

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

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

In the arithmetic control circuit of FIG. 3, the signals Tg1 to h and Tp1 to h are input from the input port 15, and the count value of the counter 13 is fetched into the latch circuit 14 with 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 the data indicating the delay time of each of the envelope and the phase.

As shown in FIG. 6, when the three vibration sensors 6 are arranged at the corners of the vibration transmission plate 8 at the positions S1 to S3, the processes described with reference to FIG. The straight line distances d1 to d3 to the position of the vibration sensor 6 can be obtained. Further, in the arithmetic control circuit 1, this linear distance d1 ~
Based on d3, the coordinates (x, y) of the position P of the vibrating pen 3 can be obtained from the Pythagorean theorem as follows.

x = X / 2 + (d1 + d2) (d1-d2) / 2X (4) y = Y / 2 + (d1 + d3) (d1-d3) / 2Y (5) Here, X and Y are the positions of S2 and S3. Is the distance along the X and Y axes between the vibration sensor 6 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.

EFFECTS OF THE INVENTION As is apparent from the above, according to the present invention, the vibration input member is detachably provided at the tip of the vibration pen,
Not only can it be easily removed and replaced if wear occurs, but the part that opens when the vibration input member is removed
As it is protected by the insulation protection member, when the vibration input member is detached, the vibrator inside the pen is damaged or destroyed, or the operator touches the vibrator carelessly and hinders its characteristics. Can be avoided. Furthermore, since the vibration input member is electrically insulating, it is possible to eliminate the risk of an electric shock when the operator touches the contact during driving when the vibration input member is detached, and various other effects are possible. Is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the structure of an information input / output device adopting the present invention, FIG. 2 (A) is an explanatory view showing the structure of the vibrating pen of FIG. 1, and FIGS. 3D is a sectional view showing a different structure of the tip portion of the vibrating pen according to the present invention, FIG.
FIG. 1 is a block diagram showing the structure of the arithmetic control circuit shown in FIG.
4 is a waveform diagram showing a detection waveform for explaining the distance measurement between the vibration pen and the vibration sensor, FIG. 5 is a block diagram showing the configuration of the waveform detection circuit of FIG. 1, and FIG. 6 is a vibration sensor. It is explanatory drawing which showed arrangement | positioning. 1 ... Arithmetic control circuit, 3 ... Vibration pen 4 ... Oscillator, 6 ... Vibration sensor 8 ... Vibration transmission plate, 51 ... Preamplifier 15, 16 ... Input port 21 ... Inner electrode 23 ... … Outer electrode, 24 …… Positioning member 25 …… Pen shaft, 26 …… Screw part 27 …… Insulation protection member 52 …… Envelope detection circuit 54,58 …… Signal detection circuit 59 …… A / D conversion circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeki Mori 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Atsushi Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Yuichiro Yoshimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Katsuyuki Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 56) References Japanese Patent Publication No. 40-24327 (JP, B1)

Claims (1)

(57) [Claims] 1. A coordinate input device for detecting a vibration input from a vibrating pen by a plurality of sensors provided on the vibration transmitting plate to detect coordinates of the vibrating pen on the vibration transmitting plate. A vibrator arranged, a vibration input member detachably attached to the tip of the vibrating pen, a vibration generated by the vibrator is transmitted to the vibration input member, and a vibration is generated between the vibrator and the vibration input member. A coordinate input device characterized in that an insulating protection member for electrically insulating and protecting the inside of the pen is provided at a portion opened when the vibration input member is detached.