JPH0786804B2 - Coordinate input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a coordinate input device, and in particular, a vibration sensor provided on a vibration transmitting plate detects vibration input from a vibrating pen to a vibration transmitting plate to detect vibration of the vibrating pen. The present invention relates to a coordinate input device that detects the coordinates of an input point.

[Prior Art] Conventionally, a coordinate input device using various input pens, tablets, and the like has been known as a device for inputting handwritten characters, figures, and the like into a processing device such as a computer. In this type of system, the input image information including characters and figures is output to a display device such as a CRT display or a recording device such as a printer.

In this type of device, the ultrasonic vibration transmitted from the vibration input pen to the tablet is input to the vibration transmission plate, and is detected from the input point by the vibration sensor provided at a predetermined portion of the vibration transmission plate, and the vibration to each sensor is detected. A configuration is known in which the coordinates of the input point are determined by the transmission time.

In such a method using ultrasonic vibration, since the input tablet can be made of a transparent material such as an acrylic plate or a glass plate, the input tablet is placed on the liquid crystal display or the like, and it is as if writing an image on paper. It is possible to configure an information input / output device that can be used in the.

[Problems to be Solved by the Invention] In the coordinate input device as described above, a piezoelectric element or the like is used as an electric / mechanical element or a mechanical / electrical conversion element forming a vibrator or a vibration sensor.

Such a vibration conversion element is a vibration transmission plate of a tablet,
Alternatively, it is fixed to a member such as a horn at the tip of the vibration pen by a method such as adhesion or pressure contact. When the vibration conversion element is fixed by adhesion, there are problems that the vibration transfer characteristics are changed by the adhesive material and the vibration transfer characteristics are varied depending on the amount of the adhered material.

Pressure contact using a spring does not cause such a large variation in vibration transfer characteristics, but due to the roughness of the end face of the element, an air layer is created between the element end face and the surface where it is pressure contacted, and the pressure contact condition Even if the control is performed, the vibration transmission characteristic also varies. In particular, since the electrodes are provided on the end faces of the conversion element, it is difficult to control the shape of the end faces to be constant in a structure in which silver paste or the like is attached, so that the variation of the vibration transfer characteristics becomes large.

Therefore, in the method of determining the vibration detection timing based on the waveform processing and performing the coordinate calculation, an error occurs in the detected coordinate value, and there is a problem that a certain coordinate detection accuracy cannot be secured for each product.

The change in the vibration transfer characteristics occurs at the pressure contact area of the vibrator of the vibrating pen and the pressure contact area of the vibration transfer plate of the tablet and the vibration sensor. Large variations in characteristics occur.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, the vibration input from the vibration pen to the vibration transmission plate is detected by the vibration sensor provided on the vibration transmission plate, and the vibration pen is used. In the coordinate input device for detecting the coordinates of the vibration input point, a horn member for transmitting the vibration generated by the vibrator of the vibrating pen to the vibration transmission plate, and a viscous fluid interposed between the vibrator and the horn member. ,
A structure having the vibrator and the pressure contact means for pressing and holding the horn member by elastic force is adopted.

[Operation] According to the above configuration, the viscous fluid is interposed between the vibrator and the horn member, and both are pressed and held by the elastic force. It becomes uniform, and it is possible to transmit vibrations without variations.

[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 11 'composed of a CRT arranged on the input tablet in accordance with the input coordinate information. The input image is displayed on.

In the figure, reference numeral 8 is a vibration transmission plate made of acrylic, glass plate or the like, and transmits the vibration transmitted from the vibration pen 3 to the vibration sensor 6 provided at three corners thereof. 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 transmission plate 8 is a CRT (or a liquid crystal display, etc.),
It is arranged on a display device 11 'capable of dot display, and dot display is performed at a position traced by the vibrating 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.

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

FIG. 2 shows the structures of the vibration pen 3 and the vibration sensor 6.

The vibrator 4 built in the vibrating pen 3 is the vibrator driving circuit 2
Driven by. 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.
After being amplified with a predetermined gain by, it is applied to the vibrator 4.

The electric drive signal is converted into mechanical ultrasonic vibration by the vibrator 4, and is transmitted to the vibration transmission plate 8 via the horn 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 in which the vibrator 4 mainly vibrates in the vertical direction in the figure is selected. 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.

On the other hand, the ultrasonic vibration transmitted on the vibration transmission plate 8 is input to the vibration sensor 6 provided at the end of the vibration transmission plate 8 and converted into an electric signal again. The output of the vibration sensor 6 is input to a waveform detection circuit 9 described later, and waveform processing for coordinate detection is performed.

In this embodiment, the vibrator 4 of the vibrating pen 3 and the vibration sensor 6 of the vibration transmitting plate 8 are fixed by pressure welding instead of bonding.

The vibrator 4 of the vibrating pen 3 is pressed against the rear end of the horn 5 by a pressing load f generated by a spring or the like. On the other hand, the vibration sensor 6 is also pressed against the vibration transmitting plate 8 by a pressing load f such as a spring.

At this time, the vibrator 4 and the vibration sensor 6 are brought into pressure contact with the horn 5, the vibration transmission plate 8 and the green 61, respectively.

The grease 61 has a consistency of 190 to 390 (JIS K2220). The grease 61 is filled between the vibrator 4 and the horn 5, and between the vibration sensor 6 and the vibration transmission plate 8 by being attached to the pressure contact surfaces of the vibrator 4 and the vibration sensor 6 when they are pressed against each other.

With such a structure, the space between the vibrator 4 and the horn 5, and between the vibration sensor 6 and the vibration transmission plate 8 is filled with the grease 61 in the space conventionally generated due to the surface roughness and deformation of the pressure contact surface. , The substantial vibration transmitting surface of both can be completely brought into close contact with each other without generating an air layer or the like. Therefore, from the oscillator 4 to the horn 5 or the vibration transmission plate 8
From the ultrasonic sensor to the vibration sensor 6 efficiently,
More energy changes in efficiency are possible. That is, the driving power of the vibrator 4 or the amplification factor after detection by the vibration sensor 6 can be reduced, and the power consumption can be reduced.

Further, since there is no variation in the degree of adhesion of the vibrator 4, the horn 5, the vibration sensor 6, and the vibration transmission plate 8 for each product, it is possible to eliminate the variation in the coordinate detection accuracy in the coordinate detection processing based on the waveform processing described later. You can The members to be interposed on the pressure contact surfaces of the oscillator 4, the horn 5, the vibration sensor 6, and the vibration transmission plate 8 are not limited to grease, and compounds having the same consistency or other fluids of high consistency can be used.

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 the three vibration sensors 6 are input to the waveform detection circuit 6 and converted into detection signals that can be processed by the arithmetic control circuit 1 in the subsequent stage. Arithmetic control circuit 1
Performs the process of measuring 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 internal counter, ROM and RAM
Built in. The drive signal generation circuit 12 outputs a drive pulse of a predetermined frequency to the vibrator drive circuit 2 of 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 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 stored in the storage area in the latch circuit 14 corresponding to each vibration sensor 6, and the result is transmitted to the microcomputer 11.

That is, the vibration transmission time is displayed 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 of FIG. 1 and a vibration transmission time measuring process based on the detection waveform. In FIG. 4, reference numeral 41 indicates a drive signal pulse applied to the vibrating 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.

The time corresponding to the distance to the vibration sensor 6 in the vibration transmission plate 8
After traveling through tg, 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 V
g, 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 d between the vibration pen 3 and the vibration sensor 6 is d = Vg with its vibration transmission time being tg. .Tg (1) This equation relates to one of the vibration sensors 6, but the same equation can indicate the distance between the other two vibration sensors 6 and the vibrating pen 3.

Further, in order to determine the coordinate value with higher accuracy, processing based on the detection of the phase signal is performed. Phase waveform 42 in Fig. 4
The distance between the vibration sensor and the vibration pen is given by d = n · λp + Vp · tp (2) if the time is tp from two specific detection points, for example, the vibration application to the zero cross point after passing the peak. Here, λp is the wavelength of the elastic wave, and n is an integer.

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

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

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,
Only the envelope of the detection signal is taken out. The timing of the peak of the extracted envelope is detected by the envelope peak detection circuit 53. The peak detection signal is an envelope delay time detection signal of a predetermined waveform by the signal detection circuit 54 composed of a mono multivibrator or the like.
Tg is formed and input to the arithmetic and control circuit 1.

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

That is, the Tg signal is converted into a pulse having a predetermined width by the monostable multivibrator 55. 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. 3, and inputs it to the detection circuit 57.

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 detected by the detection circuit 58, which is composed of a comparator.
And is 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, and the same circuit is provided for each of the other sensors.
If the number of sensors is generalized to be h, then h detection signals of envelope delay times Tg1 to h and phase delay times Tp1 to h are input to the arithmetic and control circuit 1.

In the arithmetic control circuit of FIG. 3, the above-mentioned Tg1 to h and Tp1 to h signals are input from the input port 15, and the count value of the counter 13 is taken into the latch circuit 14 by 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 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 to d3
Based on the above, 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) where X and Y are the positions of S2 and S3. This 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.

[Advantages of the Invention] As is apparent from the above, according to the present invention, since the viscous fluid is interposed between the vibrator and the horn member, both are held in pressure contact with each other by elastic force, so that the vibration The pressure contact state of the child is uniform for each product, it is possible to transmit vibrations without variation, and it is possible to make the vibration waveform input to the vibration transmission plate uniform. Therefore, the accuracy of coordinate detection processing based on vibration waveform processing is improved. It has an excellent effect that it can be greatly improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a coordinate input device adopting the present invention, FIG. 2 is an explanatory diagram showing the structure of the vibration input / output section of FIG. 1, and FIG. 3 is the arithmetic control of FIG. FIG. 4 is a block diagram showing a circuit structure, FIG. 4 is a waveform diagram showing a detection waveform for explaining the distance measurement between the vibrating pen and the vibration sensor, and FIG.
FIG. 6 is a block diagram showing the configuration of the waveform detection circuit in the figure, and FIG. 6 is an explanatory diagram showing the arrangement of vibration sensors. 1 ... Arithmetic control circuit, 3 ... Vibration pen 4 ... Oscillator, 6 ... Vibration sensor 8 ... Vibration transmission plate, 51 ... Preamplifier 15, 16 ... Input port 52 ... Envelope detection circuit 54 , 58 …… Signal detection circuit 59 …… A / D conversion circuit

Claims (1)

[Claims] 1. A coordinate input device for detecting a vibration input from a vibrating pen to a vibration transmitting plate by a vibration sensor provided on the vibration transmitting plate to detect coordinates of a vibration input point of the vibrating pen. A horn member for transmitting the vibration generated by the vibrator to the vibration transmission plate; and a viscous fluid interposed between the vibrator and the horn member,
A coordinate input device comprising: the vibrator and a press-contact means for pressing and holding the horn member by elastic force.