JPH02128212A - Coordinate input device - Google Patents

Abstract

PURPOSE:To attain coordinate detection with high reliability by controlling vibration transmitting efficiency between a vibrator and a vibration transmitting board and/or the vibration transmitting board and a vibration sensor to more than a prescribed value by means of the pressure welding force of a pressure welding means which mechanically couples the vibrator and/or the vibration sensor to the vibration transmitting board. CONSTITUTION:The vibrator 4 of a vibration pen 3 and the vibration sensor 6 of the vibration transmitting board 8 is fixed not by a bonding method but by a pressure welding method. The vibrator 4 of the vibration pen 3 is pressure- welded on the rear end part of a horn 5 by a pressure welding load (f) which is generated by a spring or the like and the vibration sensor 6 is similarly pressure-welded on the vibration transmitting board 8 by the pressure load (f) of the spring or the like. The pressure-welding force controls vibration transmitting efficiency between the vibrator 4 and the vibration transmitting board 8 and/or the vibration transmitting board 8 and the vibration sensor 6 to more than a prescribed value by means of a pressure welding force which mechanically couples the vibrator 4 and/or the vibration sensor 6 to the vibration transmitting board 8. Thus, the reliability of coordinate detection improves.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a coordinate input device, in particular, detects mechanical vibrations manually applied from a vibrator to a vibration transmission plate using a vibration sensor, and transmits the vibrations on the vibration transmission plate. The present invention relates to a coordinate input device that detects the coordinates of a vibration input point on a vibration transmission plate based on time.

[Prior Art] Coordinate input devices using various input pens, tablets, etc. have been known as devices for inputting handwritten characters, figures, etc. to a processing device such as a computer.

In this type of device, ultrasonic vibrations transmitted from a vibration input pen to a tablet are input to a vibration transmission plate, detected by vibration sensors installed at predetermined parts of the vibration transmission plate, and sent to each sensor. A configuration is known in which the coordinates of an input point are determined based on the vibration transmission time.

In such a method that uses ultrasonic S motion, the input tablet can not only be made of transparent materials such as acrylic plates and glass plates, but also conductive materials such as metal.
By placing an input tablet on top of a liquid crystal display, it is possible to construct an information input/output device that is easy to operate and can be used as if you were writing an image on paper.At the same time, it is possible to use patterned electrodes as a regular opaque tablet. An inexpensive and simple information input device can be constructed without using it.

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

Such vibration conversion elements are used in tablet vibration transmission plates,
Alternatively, it is fixed to a member such as a horn at the tip of a vibrating vent by adhesive or pressure welding. In particular, in a structure in which a silver paste or the like is attached to provide electrodes on the end face of the conversion element, it is difficult to control the shape of the end face to be constant, resulting in large variations in vibration transmission characteristics.

Therefore, in a method in which vibration detection timing is determined based on waveform processing and coordinate calculation is performed, an error occurs in the detected coordinate values, and there is a problem that a constant coordinate detection accuracy cannot be ensured for each product.

Changes in vibration transmission characteristics occur at the pressure contact part of the vibrator's vibrator and the pressure contact part of the tablet's vibration transmission plate and vibration sensor, so even if the variation in vibration transmission characteristics that occurs at each location is small, the result is quite large. Large variations in characteristics occur.

Therefore, in order to reduce the variation in vibration transmission characteristics at the press-contact parts, grease is filled between the vibration transmission plate and the vibration sensor, or the vibration transmission plate and vibration sensor are It has been proposed to fill the gap with grease, but there is a risk that the vibration transmission efficiency will deteriorate due to variations in the pressure contact force, and the detection value of the seating mark may become unstable.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a coordinate input device that can perform stable vibration transmission and highly reliable coordinate detection.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, mechanical vibrations input from a vibrator to a vibration transmission plate are detected by a vibration sensor, and vibrations on the vibration transmission plate are detected. A coordinate input device that detects the coordinates of a vibration input point on a vibration transmission plate based on a transmission time, comprising: a first press-contacting means for mechanically press-bonding the vibrator to the vibration transmission plate; and/or the vibration transmission A second pressure contact means for mechanically coupling the vibration sensor to the plate is provided, and the pressure contact force of the first and/or second pressure contact means is applied to the vibration transmitted between the two members in pressure contact. A configuration has been adopted in which the transmission efficiency is set to exceed a predetermined value.

[Operation] According to the above configuration, the pressure contact force of the pressure contact means for mechanically coupling the vibrator and/or vibration sensor to the vibration transmission plate causes the vibration between the vibrator and the vibration transmission plate and/or the vibration transmission plate - Vibration transmission efficiency between vibration sensors can be managed above a predetermined level.

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

FIG. 1(A) shows the structure of a coordinate input device employing the present invention. The coordinate input device shown in FIG. 1(A) inputs coordinates to an input tablet consisting of a vibration transmission plate 8 using a vibrating ben 3, and a display consisting of a CRT placed over the input tablet according to the input coordinate information. 11
The input image is displayed at .

In the figure, a vibration transmission plate designated by the reference numeral 8 is a vibration transmission plate made of acrylic, glass, or the like, and transmits vibrations transmitted from the vibration bezel 3 to three vibration sensors 6 provided at its corners. In this embodiment, the coordinates of the vibration ben 3 on the vibration transmission plate 8 are detected by measuring the transmission time of the ultrasonic vibration transmitted from the vibration ben 3 to the vibration sensor 6 via the vibration transmission plate 8.

The vibration transmitting plate 8 has its peripheral portion supported by an anti-reflection material made of silicone rubber or the like in order to prevent the vibration transmitted from the vibration vent 3 from being reflected at the peripheral portion and returning toward the central portion. ing.

The vibration transmission plate 8 is placed on a display device 11 that can display dots, such as a CRT (or liquid crystal display, etc.)! A dot is displayed at the position traced by the vibrating ben 3. That is, a dot is displayed at a position 11 degrees above the display corresponding to the coordinates of the detected vibrating ben 3, and the image composed of elements such as points and lines manually drawn by the vibrating ben 3 is as if written on paper. Appears after the trajectory of the vibrating ben as if it were done.

In addition, according to such a configuration, a menu is displayed on the display 11°, and the menu item is selected using the vibrating bezel, or a prompt is displayed and the vibrating ben 3 is brought into contact with a predetermined position. You can also use

The vibration ben 3 transmits ultrasonic vibration to the vibration transmission plate 8.
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 vibration vent 3 and vibration sensor 6.

A vibrator 4 built into the vibrator 3 is connected to a vibrator drive circuit 2.
Driven by A drive signal for the vibrator 4 is supplied as a low-level pulse signal from the arithmetic and control circuit 1 shown in FIG. 1, and a vibrator drive circuit 2 capable of low-impedance driving
After being amplified by a predetermined gain, the signal is applied to the vibrator 4.

The electrical drive signal is converted into mechanical ultrasonic vibration by the vibrator 4 and transmitted to the vibration transmission plate 8 via the horn 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 described above are plate waves, which have the advantage that they are less susceptible to the effects of scratches, obstacles, etc. on the surface of the vibration transmission plate 8 compared to surface waves.

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

In this embodiment, the vibrator 4 of the vibrator 3 and the vibration sensor 6 of the vibration transmission plate 8 are fixed by pressure welding rather than adhesion.

The vibrator 4 of the vibrator 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 similarly pressed against the vibration transmission plate 8 by a pressing load f such as a spring.

As described above, in this embodiment, the vibrator 4 and the vibration sensor 6 are mechanically coupled to the vibration transmission plate by pressure contact (however, the vibrator 4 is connected via the horn 5).

The pressure contact force at this time is managed as follows.

FIG. 1(B) shows the relationship between the vibration transmission efficiency calculated from the output signal of the vibration sensor 6 and the pressure contact force of the vibrator 4 or the vibration sensor. Here, the vehicle peak voltage Vpp of the detection signal was measured as shown in FIG. 1(C) under certain pressure contact force conditions, and the ratio of the voltage to the theoretical maximum value was expressed as the efficiency E. That is, the efficiency E is assumed to be constant from the measured output voltage VIII under all contact pressures.

As is clear from FIG. 1(B), when the contact force of the vibrator 4 or the vibration sensor 6 is in the range of 3 to 30 g/crn', the vibration transmission efficiency is over 95%, and the contact force is It can be seen that if the vibration transmission efficiency is maintained within this range, a substantially constant vibration transmission efficiency can be guaranteed.

Therefore, by configuring the vibrator, the vibration sensor's pressure spring, and the pressure contact mechanism to achieve this pressure contact force range, stable vibration transmission efficiency can be obtained, and the accuracy of coordinate calculation based on vibration waveform detection, which will be described later, will be stabilized. can.

In addition, since highly efficient vibration transmission is possible through pressure contact force management, the amplification factor of the vibration energy of the vibrator 4 or the detection signal of the vibration sensor 6 can be reduced, and low power consumption can be achieved. Conversely, under the same vibrator drive conditions, vibration can be transmitted over a longer distance, and the area of the input surface of the tablet can be increased.

Furthermore, it is conceivable to interpose grease 61 between the vibrator 4 and the horn 5 and between the vibration sensor 6 and the vibration transmission plate 8 during the pressure welding described above.

At this time, the vibrator 4 and the vibration sensor 6 each have a horn 5
, are pressed into contact with the vibration transmission plate 8 via grease 61.

This grease 61 has a consistency of 190 to 390 (JIS
K2220) grade is used. 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 attaching the grease 61 to the pressure contact surfaces of the vibrator 4 and the vibration sensor 6 when they are brought into pressure contact.

According to such a structure, the grease 61 is deposited in the spaces conventionally created between the vibrator 4 and the horn 5, and between the vibration sensor 6 and the vibration transmission plate 8 due to surface roughness, deformation, etc. of the pressure contact surfaces.
The substantial vibration transmission surfaces of the two can be brought into close contact with each other completely without creating an air layer or the like. Therefore, ultrasonic vibrations can be efficiently transmitted from the vibrator 4 to the horn 5 or from the vibration transmission plate 8 to the vibration sensor 6, and efficient energy conversion becomes 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 power consumption can be reduced.

Therefore, variations in coordinate detection accuracy in coordinate detection processing based on waveform processing, which will be described later, can be eliminated. The members interposed between the pressure contact surfaces of the vibrator 4, the horn 5, the vibration sensor 6, and the vibration transmission plate 8 are not limited to grease, and compounds with similar consistency or other highly consistent fluids can be used.

Next, the vibration detection system and coordinate calculation system will be explained.

Again, in FIG. 1(A), 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 1.

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

The detected coordinate information of the vibrating ben 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 human coordinate information.

FIG. 3 shows the structure of the arithmetic control circuit 1 of FIG. 1(A). Here, the structure of the drive system of the vibrating ben 3 and the vibration detection system using the vibration sensor 6 are mainly shown.

The microcomputer 11 includes an internal counter, ROM, and RAM. The drive signal generation circuit 12
It outputs a pulse of a predetermined frequency to the vibrator drive circuit 2 shown in FIG. 2A, 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 input ports 15, respectively.

The timing signal inputted from the waveform detection circuit 9 is inputted to the human powered boat 15 and 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 11° is performed via the input/output port 17.

FIG. 4 explains the detected waveform manually input to the waveform detection circuit 9 of FIG. 1(A) and the measurement process of vibration transmission time based on the detected waveform. In FIG. 4, the reference numeral 41 indicates a drive signal pulse applied to the vibrating ben 3. As shown in FIG. Ultrasonic vibrations transmitted from the vibration ben 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 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, so the envelope 42 of the detected waveform
The relationship between 1 and phase 422 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 vibration sensor 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 when a point on a certain waveform, for example a peak, is detected as indicated by reference numeral 43 in FIG. @d is the vibration transmission time t
As g, d=Vg-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 ben 3 can be expressed using the same equation.

Furthermore, in order to determine coordinate values with higher precision, processing based on phase signal detection is performed. Phase waveform 4 in Figure 4
If the time from 22 specific detection points, for example, vibration application to the zero cross point after passing the peak, is tp, then the distance between the vibration sensor and the vibration ben 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 above integer n is n-[(
Vg −tg −Vp −tp) /λp+1/Nl・
...(3) is shown. Here, N is a real number other than 0, and an appropriate value is used. For example, if it is N-2 and the fluctuation of the group delay time tg is within ±1/2 wavelength, n can be determined.

By substituting n obtained as described above into equation (2), the distance between the vibration vent 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. 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 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. From the peak detection signal, an envelope delay time detection signal Tg having a predetermined waveform is formed by a signal detection circuit 54 composed of a mono-multivibrator or the like, and is input to the arithmetic control circuit 1.

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 delay time adjustment circuit 57, and the arithmetic control circuit 1
is input.

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.
A threshold value for detecting p-flaw signals is formed. 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 of envelope delay times Tgl to h and phase delay times Tpt to h are input to the arithmetic and control circuit 1, respectively.

In the arithmetic control circuit of FIG. 3, the above Tgl~h, Tpl~
The h signal is input 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 mentioned above, the counter 13 is started in synchronization with the driving of the vibrating pen, so the latch circuit The circuit 14 receives data indicating the respective delay times of the envelope and the phase.

When three vibration sensors 6 are arranged at the positions S1 to S3 at the corners of the vibration transmission plate 8 as shown in FIG. The straight-line distances d1 to d3 to the position of the vibration sensor 6 can be determined.

Furthermore, the arithmetic and control circuit 1 can determine the seat m (X%y) of the position P of the vibrating pen 3 based on the linear distances d1 to d3 using the following formula from the 3-square theorem.

x-X/2+ (dl+d2)(di-d2)/2X・
...(4) yTomiY/2+ (d 1 + d 3) (d 1 - d 3
) /2Y.-(5) Here, X and Y are the distances along the Y-axis in X% between the vibration sensor 6 at the position 32, S3 and the sensor at the origin (position St).

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

[Effects of the Invention] As is clear from the above, according to the present invention, the mechanical vibration input from the vibrator to the vibration transmission plate is detected by the vibration sensor, and the vibration is detected based on the vibration transmission time on the vibration transmission plate. In a coordinate input device for detecting the coordinates of a vibration input point on a transmission plate, a first pressure contact means mechanically connects the vibrator to the vibration transmission plate, and/or a first pressure contact means mechanically connects the vibration input point to the vibration transmission plate. A second press-contact means for press-connecting the vibration sensor is provided, and the transmission efficiency of vibration transmitted between the two members to which the press-contact force of the first and/or second press-contact means is in press contact is a predetermined value. Since the above-mentioned configuration is adopted, the pressure contact force of the pressure contact means for mechanically coupling the vibrator and/or vibration sensor to the vibration transmission plate connects the vibrator to the vibration transmission plate, and (or) Vibration transmission plate~
By managing the vibration transmission efficiency between vibration sensors to a level higher than a predetermined value, excellent effects such as improved reliability of coordinate calculation based on vibration detection, lower power consumption, and increased input area can be expected.

[Brief explanation of drawings]

FIG. 1(A) is an explanatory diagram showing the configuration of an information input/output device adopting the present invention, and FIG. 1(B) is a diagram showing the vibration transmission efficiency depending on the pressure contact force of the vibrator or vibration sensor. , 1st
Figure (C) is a diagram explaining the evaluation of vibration detection voltage, Figure 2 is an explanatory diagram showing the structure of the vibrating pen in Figure 1, and Figure 3 is a diagram showing the structure of the arithmetic control circuit in Figure 1. Block diagram, Fig. 4 is a waveform diagram showing a detected waveform explaining distance measurement between the vibrating pen and the vibration sensor, Fig. 5 is a block diagram showing the configuration of the waveform detection circuit of Fig. 1, Fig. 6 FIG. 2 is an explanatory diagram showing the arrangement of vibration sensors. 1... Arithmetic control circuit 3... Vibration pen 4... Vibrator 6... Vibration sensor 8... Vibration transmission plate
51...Preamplifier 15.16...Input Portro 1...Grease Ni Moromi IFI'l Co. ``Roma'' Figure 4, trench 7m, Hidetari Tomari i's Fu'' 0-17 page, Figure 5, Jfa Wholesale (2〉Lee Drunken I 4i Buddha δ'b extraction) Town Meshiro, Figure 6

Claims (1)

[Claims] 1) Mechanical vibration input from the vibrator to the vibration transmission plate is detected by a vibration sensor, and the coordinates of the vibration input point on the vibration transmission plate are determined based on the vibration transmission time on the vibration transmission plate. In the coordinate input device for detection, a first pressure contact means mechanically press-connects the vibrator to the vibration transmission plate, and/or a second pressure contact means mechanically press-connects the vibration sensor to the vibration transmission plate. A pressure contact means is provided, and the pressure contact force of the first and/or second pressure contact means is set so that the transmission efficiency of vibration transmitted between the two members in pressure contact is equal to or higher than a predetermined value. A coordinate input device characterized by: 2) The coordinate input device according to claim 1, characterized in that a fluid with high consistency is interposed between the vibrator and the vibration transmission member.