JPH02128213A - Coordinate input device - Google Patents

Abstract

PURPOSE:To improve the precision of coordinate operation by setting the surface coarse and the surface waviness of at least one of the contact surfaces of a vibration transmitting member (horn) and a vibrator provided in a vibration pen to be less than a prescribed value. CONSTITUTION:The vibration pen 3 transmitting ultrasonic vibration to the vibration transmitting board 8 has the vibrator 4 inside it, and it transmits ultrasonic vibration which the vibrator 4 is generated to the vibration transmitting board 8 through the horn 5 whose tip is sharp. For manufacturing the horn 5, it is controlled that the contact surface coarse of the horn 5 comes to be less than 6S(JIS B 0601) and a surface waviness width comes to be within the range of the surface coarse in the contact surface with the vibrator 4. Consequently, the adhesion of the vibrator 4 and the horn 5 is improved, and vibration generated in the vibrator 4 can efficiently be transmitted to the horn 5. Thus, the precision of coordinate operation improves.

Description

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

[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 system, input image information consisting of characters, graphics, etc. is output to a display device such as a CRT display or a recording device such as a printer.

In this type of device, ultrasonic vibrations transmitted from a vibrating pen to a tablet are input to a vibration transmission plate, detected from the input point by a vibration sensor installed at a predetermined part of the vibration transmission plate, and transmitted to each sensor. The coordinates of the input point are determined by the vibration transmission time.

A vibrating pen uses a piezoelectric element or the like as a vibrator, and the vibration of the vibrator is transmitted to a vibration transmission plate by a pen tip having a horn shape or the like to improve vibration transmission efficiency. Conventionally, the vibrator, which is the vibration generation source of a vibrating pen, and the pen tip were usually fixed by adhesive.

[Problem B to be solved by the invention] However, in the conventional example described above, the vibration characteristics obtained at the tip of the pen tip differ depending on the amount of adhesive, and as a result, the vibration characteristics of each pen are measured and the propagation speed etc. It was necessary to correct the constant. In other words, the overall vibration transmission that is synthesized by both the vibrator and the pen tip depends on the amount of adhesive on the adhesive surface, the thickness of the adhesive layer, the distribution of the adhesive, and the amount of adhesive that protrudes from the adhesive surface during bonding. The resonance characteristics of the system change.

Therefore, the signal waveform detected by the sensor differs depending on each input pen, and in order to construct a highly accurate input device, it is necessary to measure the vibration characteristics of each vibrating pen, which is extremely costly. There was a drawback.

Also, when producing vibrating pens in large quantities, it is of course desirable that all vibrating pens have the same characteristics;
In this case, careful attention must be paid to the management and control of the amount of adhesive for the vibrator and the pen tip, as well as the adhesive method, resulting in high costs and problems in that no improvement in yield can be expected.

An object of the present invention is to solve the above-mentioned problems and to make it possible to obtain a vibrating pen with good vibration transmission characteristics without requiring a complicated manufacturing process in an ultrasonic vibration type coordinate input device. .

[Means for Solving the Problems] In order to solve the above problems, in the present invention, vibrations input from a vibrating pen are detected by a plurality of sensors provided on the vibration transmitting plate, and the vibration transmitting plate of the vibrating pen is In the coordinate input device for detecting the coordinates of A configuration was adopted in which the surface roughness and surface waviness of at least one of the mutually contacting surfaces of the two were set to below predetermined values.

[Function] According to the above configuration, vibration can be efficiently transmitted between the vibrator and the transmission member that transmits vibration to the vibration transmission plate.

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

FIG. 3 shows the structure of an information input/output device employing the present invention. The device shown in FIG. 3 not only detects coordinates but also displays input information. That is, the illustrated device inputs coordinates to an input tablet consisting of a vibration transmission plate 8 using a vibrating pen 3, and displays a display 1 consisting of a CRT placed over the input tablet according to the input coordinate information.
The input image is displayed at 1'.

The reference numeral 8 in the figure is a vibration transmission plate made of acrylic, glass, etc., which transmits vibrations transmitted from the vibrating pen 3 to three imaging sensors 6 provided at its corners. In this embodiment, the coordinates of the vibrating pen 3 on the vibration transmitting plate 8 are detected by measuring the transmission time of the ultrasonic vibration transmitted from the vibrating pen 3 to the vibration sensor 6 via the vibration transmitting plate 8.

In order to prevent the vibration transmitted from the vibrating pen 3 from being reflected at the periphery and returning toward the center, the periphery of the vibration transmission plate 8 is supported by an anti-reflection material 7 made of silicone rubber or the like. has been done.

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

Further, according to such a configuration, a menu is displayed on the display 11', and input methods such as having the vibrating pen select the menu item or displaying a prompt and touching the vibrating pen 3 at a predetermined position can be performed. It can also be used.

The vibrating pen 3 transmits ultrasonic vibration to the vibration transmitting 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 5 with a sharp tip.

A vibrator 4 built into the vibrating pen 3 is connected to a vibrator drive circuit 2.
is driven at a predetermined frequency. Vibrator drive circuit 2
The electrical drive signal generated is converted into mechanical ultrasonic vibration by the vibrator 4, and transmitted to the vibration transmission plate 8 via the horn 5 configured as described above.

The vibration frequency of the vibrator 4 is selected to a value that can generate plate waves in the vibration transmission plate 8 made of acrylic, glass, or the like. Further, when driving the vibrator, a vibration mode in which the vibrator 4 mainly vibrates in a direction perpendicular to the vibration transmission plate 8 is selected.

Further, by setting the vibration frequency of the vibrator 4 to the resonance frequency of the vibrator 4, efficient vibration conversion is possible.

The elastic waves transmitted to the vibration transmission plate 8 as described above are plate waves, which have the advantage of being less affected by scratches and obstacles on the surface of the vibration transmission plate 8 than surface waves.

FIGS. 1 and 2 show the structure of a vibrator and its electrodes in a vibrating pen according to the present invention.

As shown in both figures, the vibrator 4 used in this example is a cylindrical piezoelectric element, and polarization is performed inside and outside the cylinder, making use of the piezoelectric transverse effect (the direction of the applied electric field and direction of displacement is perpendicular).

Reference numeral 5 denotes a pen tip (has a horn shape. This pen tip is simply referred to as a horn) that amplifies the vibration of the vibrator 4 and inputs the vibration to the vibration transmission plate 8. Reference numeral 25 fixes the horn 5 and inputs the coordinates. This is a pen holder that makes up the pen body.

Reference numeral 24 connects the outer electrode 23 and the inner electrode 21 to the vibrator 4.
It is a positioning member for positioning against the pen holder 25, and its outer periphery is fitted into the pen holder 25 in this embodiment,
It also serves to position the vibrator 4.

A compression spring 22 is in contact with the outer electrode 23 and presses the vibrator 4 onto the horn 5 together with the spring portion of the inner electrode 21 .

When manufacturing the horn 5 in this embodiment, the contact surface roughness of the horn 5 on the contact surface with the vibrator 4 is 6S (JI
S B 0601) or less, and the surface waviness width is controlled to be within this surface roughness range. This increases the adhesion between the vibrator 4 and the horn 5, allowing the vibrations generated by the vibrator 4 to be efficiently transmitted to the horn 5, and making it possible to obtain a sufficient vibration amplitude at the tip of the horn.

Here, the reason why the above-mentioned surface roughness condition was set to 6.3S or less will be explained. Table 1 shows the vibrator 4 of the vibrating pen 3.
Experimental results regarding vibration transmission between the pen tip and the horn 5 of the pen tip are shown below.

Table 1 (unit μ) Here, two vibrating pens with poor vibration output characteristics and two vibrating pens with good vibration output characteristics are prepared, and the characteristics of the surface of the horn 5 of the pen tip of these vibrating pens, that is, the maximum peak height , up to 6 depths, measured values R,lR,,R, were measured.

The measured values R,,R,,R,are as follows.

Rx: When the sampled part is sandwiched between two straight lines parallel to the average line of the part extracted by the standard length from the cross-sectional curve, these two
The distance between straight lines is measured in the direction of the vertical magnification of the cross-sectional curve.

R2=Choose the line that passes through the third peak from the highest and the line that passes through the bottom of the third valley from the highest among the straight lines parallel to the average line of the part extracted by the reference length from the cross-sectional curve, and calculate the line between these two trees. The distance between straight lines is measured in the direction of the vertical magnification of the cross-sectional curve.

R1: Pick out a part of measurement length 1 from the roughness curve in the direction of its center line, set the center line of this cut out part as the X axis, the direction of vertical magnification as the Y axis, and make the roughness curve y = f (x) When expressed as , the value of R1 is given by the following formula.

Also, in Table 1, the vibrating pens with poor output characteristics are:
An input was made at a predetermined point on the vibration transmission plate, and a detected voltage above a certain level could not be obtained by the predetermined vibration sensor.

Specifically, in the same measurement system used in the experiment, 2 in Table 1
1.5-1.6 for one good vibrating pen (number 3.4)
While an output gain of V was obtained, the two defective vibrating pens (number 1.2) had an extremely low output voltage of about 0.8 to 1.0 V, about half to 2/3 of that of the good pens. I've only gotten so much.

As is clear from the measured values of the pressure contact surface of the pen tip of each vibrating pen in Table 1 with the vibrator of the horn, the more uneven the pressure contact surface is, the lower the signal strength obtained by the vibration sensor is.

The applicant also conducted a number of measurements on a vibrating pen (not shown), and found that the vibration transmission efficiency drops sharply at a surface roughness of around 63. Of course, the driving conditions for each vibrating pen, the pressure contact conditions between the vibrator and the horn, etc. are the same for all pens, so even if you change the pressure contact conditions between the vibrator and the horn, the above boundary value will not be maintained. It was also the case that the vibration transmission efficiency changed drastically at the boundary.

When the surface roughness and surface waviness of the horn 5 become larger than the above-mentioned values, the vibration amplitude at the tip of the horn 5 decreases, and the vibration energy incident on the vibration transmission plate shown by reference numeral 8 in FIG. 3 decreases significantly. . As a result, the mechanical energy propagating on the vibration transmission plate 8 and reaching the sensor 6 is small, and the electrical energy output from the sensor is also small, and as a result, the S of the detection signal obtained by the vibration sensor 6 is small. /
Although the N ratio decreases and the accuracy of coordinate calculation decreases, the horn 5
By setting the roughness and waviness of the contact surface with the vibrator 4 as described above, vibration input can be performed efficiently, and the coordinate calculation described below can be performed with high accuracy.

In addition, by improving the vibration transmission efficiency, power consumption can be reduced by reducing the drive energy of the vibrator 4 or the amplification factor of the output signal of the vibration sensor 6, or by reducing the drive energy of the same vibrator 4, the vibration The output amplification factor of sensor 6 enables vibration transmission over a longer distance,
Another advantage is that it can easily accommodate larger input surfaces.

The roughness of the contact surface of the horn 5 with the vibrator 4 can be slightly controlled by applying lapping to the contact surface.

The configuration and operation of the vibration waveform detection system and coordinate calculation processing system will be explained below.

Referring again to FIG. 3, the vibration sensor 6 provided at the corner of the vibration transmission plate 8 is also constituted by a mechanical/electric 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 9, and are converted into detection signals that can be processed by the subsequent arithmetic control circuit 1. The arithmetic control circuit 1 performs vibration transmission time measurement processing and detects the coordinate position of the vibrating pen 3 on the vibration transmission plate 8.

The detected coordinate information of the vibrating pen 3 is processed in the arithmetic control circuit 1 according to the output method by the display 11'. That is, the arithmetic control circuit outputs the display 11 via the video signal processing circuit 10 based on the input coordinate information.
’ output operation is controlled.

Next, the structure and operation of the coordinate processing system will be explained in detail.

FIG. 4 shows the structure of the arithmetic control circuit 1 of FIG.

The microcomputer 11 includes an internal counter, ROM, and RAM. The drive signal generation circuit 12
It outputs a drive pulse of a predetermined frequency to the vibrator drive circuit 2 shown in the figure, 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 for coordinate detection from the output of the vibration sensor 6 as described later.

The timing signal input from the waveform detection circuit 9 is input to the input port 15 and compared with the count value in the latch circuit 14 by the determination circuit 16, 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 calculations are performed using this vibration transmission time value.

The output control process of the display 11' is carried out by the input/output port 1.
This is done via 7.

FIG. 5 explains the detected waveform input to the waveform detection circuit 9 of FIG. 3 and the vibration transmission time measurement process based on the detected waveform. In FIG. 5, reference numeral 41 indicates a drive signal pulse applied to the vibrating pen 3. In FIG.

The ultrasonic vibration transmitted from the vibrating pen 3 driven by such a waveform to the vibration transmission plate 8 passes through 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. 5 indicates a signal waveform detected by the vibration sensor 6. The plate wave used in this example is a dispersive wave, so the envelope 4 of the detected waveform
The relationship between 21 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. From this difference in group velocity and phase velocity, the distance between the vibrating pen 3 and the vibration sensor 6 can be detected.

First, if we focus only on the envelope 421, its speed is Vg, and when a point on a certain waveform, for example, a peak, is detected as indicated by reference numeral 43 in FIG. is the vibration transmission time tg
As d person v g −t g ,,・(
1) This formula relates to one of the vibration sensors 6, but the same formula applies to the other two vibration sensors 6 and the vibration pen 3.
can show the distance of

In order to determine even more precise coordinate values, the phase waveform 42 shown in FIG. 5 is processed based on phase signal detection.
2 specific detection point, for example, if the time from vibration application to the zero crossing point after passing the peak is tp, then the distance between the vibration sensor and the vibration pen is d:l++n・λp+VP e tp
*jll (2). Here, λp is the wavelength of the elastic wave, and n is an integer.

From the above equation (2) and equation (2), the above integer n is N= [(Vg -tg -Vp -tp) /
It is expressed as λp+1/Nl... (3). Here, N is a real number other than O, and an appropriate value is used. For example, if N=2, n can be determined if it is within ±1/2 wavelength.

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

Measurement of the two vibration transmission times tg and tp shown in FIG. 5 is performed by the waveform detection circuit 9. The waveform detection circuit 9 is constructed as shown in FIG.

In FIG. 6, the output signal of the vibration sensor 6 is amplified to a predetermined level by the amplification circuit 51 described above.

The amplified signal is input to the envelope detection circuit 52, and only the envelope of the detection signal is extracted. The timing of the peak of the extracted envelope is detected by the envelope peak detection circuit 53. The peak detection signal is formed into an envelope delay time detection signal Tg having a predetermined waveform by a signal detection circuit 54 composed of a mono-multi-by-break circuit, etc., and is input to the arithmetic control circuit 1.

Furthermore, a phase delay time detection signal 'rp 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 is input to the arithmetic control circuit 1.

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 Tp1 to h are input to the arithmetic and control circuit 1, respectively.

In the arithmetic control circuit of FIG. 4, the above 7g1~h, Tp1~
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 the 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 distance @di~d3 to the position of the vibration sensor 6 can be determined.

Furthermore, the arithmetic control circuit 1 determines the coordinates (X) of the position P of the vibrating pen 3 based on the linear distances d1 to d3.

y) can be obtained from the Pythagorean theorem as follows.

x-x/2+ (dl+d2)(di-d2) /2X
...(4) Y −Y/2 + (di + d3
) (di - d3) /2Y ... (5) Here, X and Y are the horn 5 at the positions S2 and S3 and the origin (position St
) is the distance along the X and Y axes of the sensor.

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

In the above embodiment, the input tablet by the vibration transmission plate 8 is C
Although a configuration has been shown in which the input tablet and the display are overlapped with the display tt' by RT, it is not necessary to arrange the input tablet and the display overlapping in this way, and they may be separate bodies.

Further, the display may be of another display type, such as a liquid crystal display.

In addition, in the above embodiment, an example was shown in which the surface roughness of the contact surface of the horn 5 of the vibrating pen with the vibrator 4 is managed, but of course, the roughness of the contact surface with the horn 5 on the vibrator side is also controlled. By doing so, the vibration transmission efficiency between the two can be significantly improved, and even greater effects can be expected.

Further, by filling a substance such as grease between the vibrator 4 and the horn 5, the acoustic impedances of the two can be matched, and even more efficient vibration energy can be obtained.

[Effects of the Invention] As is clear from the above description, according to the present invention, vibrations input from a vibrating pen are detected by a plurality of sensors provided on the vibration transmitting plate, and the vibrations are transmitted on the vibration transmitting plate of the vibrating pen. In the coordinate input device for detecting the coordinates of the vibrating pen, the vibrating pen is provided with a vibrator for generating vibration and a vibration transmitting member that transmits the vibration of the vibrator to a vibration transmitting plate, and the vibration transmitting member and the vibrator are connected to each other. Since the structure is such that the surface roughness of at least one of the contact surfaces is set to a predetermined value or less, vibration can be efficiently transmitted between the vibrator and the vibration transmission member, improving coordinate calculation accuracy. It is possible to reduce power consumption by reducing the transducer drive energy and the amplification factor of the detection signal, and it also has excellent features such as being able to easily accommodate large input surfaces and facilitating product quality control. There are advantages.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a vibrating pen according to the present invention;
Fig. 2 is an exploded perspective view of the vibrating pen shown in Fig. 1, Fig. 3 is an explanatory diagram showing the configuration of an information input/output device employing the present invention, and Fig. 4 shows the structure of the arithmetic control circuit shown in Fig. 3. 5 is a waveform diagram showing a detected waveform explaining distance measurement between the vibrating pen and the vibration sensor, and FIG. 6 is a block diagram showing the configuration of the waveform detection circuit shown in FIG. FIG. 7 is an explanatory diagram showing the arrangement of vibration sensors. 1... Arithmetic control circuit 3... Vibration pen 4... Vibrator 6... Vibration sensor 8... Imaging transmission board
51...Preamplifier 15.16...Input port 52...Envelope detection circuit 54.58...Signal detection circuit 59...A/D conversion circuit Figure 1: 11 Articles 11, 7, 0, 4, 4, 5, 4, 5

Claims (1)

[Scope of Claims] 1) A coordinate input device that detects the coordinates of the vibrating pen on the vibration transmitting plate by detecting the vibration input from the vibrating pen using a plurality of sensors provided on the vibration transmitting plate. The pen is provided with a vibrator for generating vibrations and a vibration transmission member that transmits the vibrations of the vibrator to a vibration transmission plate, and the surface roughness of at least one of the mutual contact surfaces of the vibration transmission member and the vibrator is set to a predetermined surface roughness. A coordinate input device characterized in that the coordinates are set to a value less than or equal to a value. 2) The coordinate input device according to claim 1, wherein the waviness width of at least one of the mutual contact surfaces of the vibration transmission member and the vibrator is set to be equal to or less than the surface roughness.