JPH02128214A - coordinate input device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention detects vibration input from a coordinate input device, particularly a vibrating pen, using a vibration sensor provided at a predetermined position on the vibration transmission plate. The present invention relates to a coordinate human power device that detects the position of vibration input to the vibration transmission plate by the vibration pen from the vibration transmission 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 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 vibration input 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. A configuration is known in which the coordinates of an input point are identified by transmission time. In the ultrasonic method, the structure of the input tablet is relatively simple, the device configuration is simple and inexpensive, and the tablet is made of a transparent material.
It has the advantage of being able to be used over the display and original.

[Problems to be Solved by the Invention] Conventionally, a vibration vent for applying vibration force to a vibration transmission plate has been constructed as shown in FIG. In FIG. 7, reference numeral 4' denotes a cylindrical piezoelectric element, which is fixed to the horn 5 by bonding, pressure welding, etc. in order to efficiently transmit vibration to the vibration transmission plate.

It is known that the a mode of the plate wave is convenient for waveform processing for coordinate detection as the wave transmitted to the vibration transmission plate, and the piezoelectric element 4' transmits this plate wave to the vibration transmission plate (not shown). The vertical C in the figure is used so that it can be generated.

In order to generate the plate wave a-mode, the thickness of the vibration transmission plate should be within the practical range of 0.5-1. On the order of On+m, the vibration frequency is selected to be 300 kHz to 500 K)1z. In order to efficiently generate frequencies in this range, the piezoelectric element 4
The resonant frequency of ' is also usually matched to this frequency band. As shown in Figure 7, in a cylindrical 33-mode element, in order to achieve this resonance band, its length l and diameter r
is limited.

The diameter r is determined by the required output amplitude and is approximately φ4~61
Although 1In is preferable, the length 1 is determined by the frequency constant of the material, and in the case of materials such as negative ceramics, it is often almost the same as the diameter r in the above frequency band.

The problem here is that the cylindrical piezoelectric element has a diameter r and a length L.
In an element where the values are approximately equal, vibrations in the radial direction of the element (both directions are shown by arrows) are coupled in addition to the necessary vibration direction in the pen axis direction (vertical direction in Figure 7), and pure longitudinal vibration is This means that you will not be able to obtain it from the beginning. As a result, other modes are mixed in the vibration input to the vibration transmission plate, the detected waveform is distorted, and the vibration detection timing is affected, making highly accurate coordinate detection impossible.

Furthermore, in the structure shown in FIG. 7, the electrodes for signal power are provided on the upper and lower surfaces of the piezoelectric element 4', and the lower side is in contact with the horn 5, so it is very difficult to take out the electrical electrodes. There was a problem that.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a coordinate input device that can input mechanical vibration in a desired single vibration mode to a vibration transmission plate and that can simplify the structure of a vibrating pen.

[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 vibration sensor provided at a predetermined position on a vibration transmission plate, and the vibrations are transmitted. In a coordinate input device that detects a position of vibration input to a vibration transmission plate by the vibration pen from a vibration transmission time on the plate, a vibration direction of a vibration generation vibrator provided in the vibration pen is perpendicular to a polarization direction. The piezoelectric element is composed of a hollow cylindrical piezoelectric element that generates longitudinal vibrations, and the polarization of the piezoelectric element is formed between the outer and inner surfaces of the cylindrical element.

[Function] According to the above configuration, the vibration component in the thickness direction of the element can be extremely reduced, and the vibrator can be vibrated in a single vibration mode, so that the coupling of unnecessary vibration components causes the vibration transmission plate to It is possible to prevent the input vibration waveform from being distorted.

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

FIG. 1 shows the structure of an information input/output device employing the present invention. The information input/output device shown in FIG. 1 inputs coordinates to an input tablet consisting of a vibration transmitting plate 8 using a vibrating pen 3, and a display 11° consisting of a CRT placed over the input tablet according to the input coordinate information. The input image is displayed on the screen.

In the figure, a vibration transmission plate designated by reference numeral 8 is a vibration transmission plate made of acrylic, glass, or the like, and transmits vibrations transmitted from the photographing ben 3 to the three vibration sensors 6. The vibration transmitting plate 8 has its peripheral portion covered with a vibration isolating material 7 made of silicone 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 center. It is supported by In order to reduce the influence of reflected waves from the boundary surface of the vibration isolator 7, the vibration sensor 6 is mounted on or very close to the boundary surface of the vibration isolator 7. The mounting method may be adhesive or pressure welding.

The vibration transmission plate 8 is arranged on a display device 11, such as a CRT (or liquid crystal display, etc.) capable of displaying dots, and displays dots at the position traced by the vibrating ben 3. That is, a dot is displayed at a position on the display 11 that corresponds to the detected coordinates of the vibrating ben 3, and an image composed of elements such as points and lines input by the vibrating ben 3 is displayed as if it were 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 by 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(A) shows the structure of the vibrating vent 3. A vibrator 4 built into the vibrator 3 is driven by a 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 shown in FIG.
After being amplified by a predetermined gain by a vibrator drive circuit 2 capable of low impedance driving, 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 diaphragm 8 via the horn section 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.

FIG. 2(B) shows the structure of the vibrator 4 in this example.

In this embodiment, the vibrator 4 is constituted by a hollow cylindrical piezoelectric element that generates longitudinal vibration (K31 mode) whose vibration direction is perpendicular to the polarization direction. Its length is °C, its outer diameter is rl, and its inner diameter is r2. The thickness (rl-r2) is t. The direction of the generated vibration is the direction of arrow vi.

Polarization of the element occurs at right angles to this vibration direction, that is, between the outer circumferential surface A and the inner circumferential surface B.

In other words, such a hollow cylindrical element is produced by rolling a flat piezoelectric element with a thickness t as shown in FIG.
If the length λ and the thickness t are t(i), vibration in a single longitudinal direction vi can be obtained.

In other words, the non-hollow cylindrical element shown in Figure 7 has a shape with a bottom surface of φ = 4, in which the diameter r and 1 are almost equal, and unnecessary vibration components due to the coupling of radial vibrations are generated. is input to the vibration transmission plate, whereas, for example, rl=5, r2=31, u=5 (for example, m
m), t=1, t<X can be realized, and only the vibration component in the pen axis direction having sufficient amplitude can be input to the vibration transmission plate.

Therefore, in the waveform detection and coordinate calculation described later, it is possible to accurately determine the waveform detection timing and perform highly accurate coordinate input.

Furthermore, as is clear from the above polarization direction, the electrodes may be provided on the outer circumferential surface A and the inner circumferential surface B of the element, and the electrodes can be easily taken out even if the top or bottom surface of the element is fixed to the horn. Can be done.

In addition, if the electrodes on the outer circumferential surface A and the inner circumferential surface B are drawn out from the end face of the element at the positions indicated by the symbol E%F in FIG. 2(D),
Electrical coupling with the element can be more easily achieved using lead wires or contact electrodes.

Note that although a hollow circular piezoelectric element has been exemplified above, the same effect as described above can be obtained even if a hollow rectangular cylinder-shaped piezoelectric element is used as the vibrator 4, as shown in FIG. 2(E). Needless to say. Of course, the number of corners of the rectangular tube is not limited to the four illustrated.

Next, the configuration and operation of the vibration waveform detection system and the coordinate detection system will be explained.

Again, in FIG. 1, 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 the waveform detection circuit 9, and are converted into detection timing signals that can be processed by the arithmetic control circuit 1 through waveform detection processing, which will be 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 input from the waveform detection circuit, and further detects the coordinate input position of the vibrating pen 3 on the vibration transmission plate 8 from this vibration transmission time.

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 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 shown in FIG.

Here, the structure of the drive system of the vibrating pen 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 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 from the output of the vibration sensor 6 as described later. These timing information are input manually to the input ports 15, respectively.

A timing signal manually input from the waveform detection circuit 9 is input to the input port 15 and stored in a 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 of the waveform detection timing information from the plurality of vibration sensors 6 has been manually input, and the microcomputer 1
Notify 1.

Output control processing for the display 11° is performed via the input/output port 17.

FIG. 4 explains the detected waveform input to the waveform detection circuit 9 of FIG. 1 and the vibration transmission time measurement process based on the detected waveform. In FIG. 4, reference numeral 41 indicates a drive signal pulse applied to the vibrating pen 3. Ultrasonic vibrations transmitted from the vibrating pen 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 advancing speed of the envelope is group velocity vg1 and the phase velocity is Vp. The distance between the vibrating pen 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. lad is dmiV g-t g with the vibration transmission time as tg
-(1) Although this formula 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 formula.

Furthermore, in order to determine coordinate values with higher precision, the phase waveform 4 shown in FIG.
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 vent is den ・λp+Vp T tP ++*
(2), where 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+t/N
l... (3) It is shown as. Here, N is a real number other than O, 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 "rp" is formed by the detection circuit 58 from this Tg flaw signal timing and the original signal delayed by the delay time adjustment circuit 57, and is manually input to the arithmetic control circuit 1.

That is, the Tg flaw signal is converted into a pulse of a predetermined width by the 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 h1 and phase delay times Tpt to h are input to the arithmetic control circuit 1, respectively.

In the arithmetic control circuit of FIG. 3, the above T g'l~h, Tp
The l to h signals are inputted 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 described above, since the counter 13 is started in synchronization with the driving of the vibration ben, the latch 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. Straight line distance to the position of vibration sensor 6! 1d1 to d3 can be obtained.

Further, the arithmetic and control circuit 1 can determine the coordinates (X Sy) of the position P of the vibrating pen 3 based on the straight line distances 11dl to d3 using the following formula from the 3-square theorem.

x=X/2+ (d1+d2)(d1-d2
) /2X...(4) y=y/2+ (a 1-+-d3) (a t-d3)
/2y...(5) Here, X and Y are the distances along the X and Y axes between the vibration sensor 6 at the positions S2 and S3 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 clear from the above, according to the present invention, vibrations input from a vibrating pen are detected by a vibration sensor provided at a predetermined position on the vibration transmission plate, and an image is taken on the vibration transmission plate. In the coordinate input device for detecting the position of vibration input to the vibration transmission plate by the vibration pen from the dynamic transmission time, the vibration direction of the vibration generating vibrator provided in the vibration pen is perpendicular to the polarization direction. It is composed of a hollow cylindrical piezoelectric element that generates vibrations, and the polarization of this piezoelectric element is formed between the outer and inner surfaces of the cylindrical shape of the element. Since the vibration component can be made extremely small and the vibrator can be vibrated in a single vibration mode, it is possible to prevent the vibration waveform applied manually to the vibration transmission plate from being distorted due to coupling of unnecessary vibration components. Therefore, the timing at which the vibration input to the vibration transmission plate reaches the vibration sensor can be accurately determined by waveform processing of the output signal of the vibration sensor, and there is an excellent advantage that highly accurate coordinate detection can be performed.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the configuration of an information input/output device adopting the present invention, Fig. 2 (A) is an explanatory diagram showing the structure of the vibrating pen of Fig. A perspective view showing the structure of a vibrator used in a pen, Figure 2 (C) is similar to Figure 2 (A)
Perspective views illustrating the structure of the device, Figures 2 (D) and (E)
is a perspective view showing the structure of a different vibrator, FIG. 3 is a block diagram showing the structure of the arithmetic control circuit in FIG. 1, and FIG. 4 is a detection 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 in FIG. 1, FIG. 6 is an explanatory diagram showing the arrangement of the vibration sensor, and FIG. FIG. 1... Arithmetic control circuit 3... Vibration pen 4... Vibrator 6... Vibration sensor 8... Vibration transmission plate
51...Preamplifier 15.16...Input port lift button m story/I skew r Figure 2 Figure 1 Indicates 1 degree of pupil silence Figure 4 Figure 4 Handbook Arrow 1 C] No. j, 0-, 71 convex Figure 5 ii, fit; JL (? It'; La f, Fl,
ep, W Figure 6

Claims (1)

[Claims] 1) Detect the vibration input from the vibration pen with a vibration sensor installed at a predetermined position on the vibration transmission plate, and determine the position of vibration input to the vibration transmission plate by the vibration pen from the vibration transmission time on the vibration transmission plate. In the coordinate input device for detection, the vibration generating vibrator provided in the vibrating pen is composed of a hollow cylindrical piezoelectric element that generates vibration in the longitudinal direction with the vibration direction perpendicular to the polarization direction. A coordinate input device characterized in that the polarization of the piezoelectric element is formed between a cylindrical outer surface and an inner surface of the element.