JPS63239518A - Coordinates input device - Google Patents

Abstract

PURPOSE:To obtain a high detecting accuracy even when an oscillating pen is inclined and a pen pressure is insufficient by detecting the oscillation from the oscillating pen by plural sensors provided at an oscillation transfer plate to provide a fine ruggedness on an oscillating input surface and detecting coordinates. CONSTITUTION:An oscillation transfer plate 8 is composed of a transparent acrylic or glass plate, etc., and the oscillation transferred from an oscillating pen 3 is transferred to three oscillating sensors 6 provided at an angle part. By measuring the transfer time of an ultrasonic oscillation transferred to the sensors 6, the coordinates on the plate 8 of the pen 3 are detected. For the plate 8, the peripheral part is supported by a reflection preventing material 7 in order to execute the reflection prevention of the oscillation. The plate 8 is arranged on an indicator 11' and executes the dot displaying to the position instructed by the pen 3. Since the surface of the plate 8 provides a fine ruggedness to the extent not to reduce a transparency, a surface wave component is attenuated and an error does not occur. Even when the pen 3 is inclined by the unevenness and the pen pressure is insufficient, a coordinate detecting accuracy is not reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention detects vibrations input from a coordinate input device, particularly a vibration ben, using a plurality of sensors provided on a vibration transmission plate, and transmits the vibrations of the vibration ben. This invention relates to a coordinate input device that detects coordinates on a board.

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

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

l) Detecting a change in resistance value of a sheet material placed facing the resistive film.

2) A method that detects electromagnetic or electrostatic induction from conductive sheets placed opposite each other.

3) A method that detects ultrasonic vibrations transmitted from the input vent to the tablet.

In the above methods 1) and 2), it is difficult to form a transparent tablet because a resistive film or a conductive film is used. On the other hand, in method 3), the tablet can be constructed from a transparent material such as an acrylic plate or a glass plate, so the input tablet can be placed on top of a liquid crystal display, etc., and can be used as if it were writing an image on paper. It is possible to construct a good information source system.

[Problems to be solved by the invention] However, in the method using ultrasonic vibration, vibration transmission is hindered by scratches and obstacles on the vibration transmission plate of the tablet.
There is a problem that detection accuracy decreases.

Therefore, a technique has been proposed in which the vibration transmission plate of the tablet is vibrated using plate waves among the elastic waves to reduce the effects of scratches and obstacles on the vibration transmission plate. However, this method has the problem that highly accurate coordinate input cannot be performed because the surface wave component of the vibration affects the waveform detected by the vibration sensor depending on operating conditions such as the pen pressure or the tilt of the vibrating ben.

The present invention aims to improve the above-mentioned problem of detection error in the ultrasonic method, which has various advantages such as making the tablet transparent easily and being relatively inexpensive compared to other methods.

[Means for Solving the Problems] In view of the above, according to the present invention, the vibration of the vibration vent is detected by a plurality of sensors provided on the vibration transmitting plate, which receives input from the vibration vent having a vibration generating means. In a coordinate input device that detects coordinates on a transmission plate, a configuration is adopted in which fine irregularities are provided on the vibration input surface of the vibration transmission plate.

[Function] According to the above configuration, even if the vibrating ben is tilted or the pen pressure of the vibrating ben is not sufficient, the surface of the vibrating transmitting plate reduces coordinate detection accuracy due to the unevenness of the vibrating transmitting plate. Wave components can be removed, and at the same time, writing quality can be improved, external light can be diffusely reflected, and display visibility can be improved when a display is provided below the vibration transmission plate.

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

FIG. 1 shows the structure of a coordinate input device employing the present invention. The information input/output device shown in FIG. 1 inputs coordinates to an input tablet made of a vibration transmission plate 8 using a vibrating ben 3, and a display 11' made 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, the reference numeral 8←→ is a vibration transmission plate made of acrylic, glass, etc., which transmits the vibrations transmitted from the vibration pen 3 to the vibration sensors 6 provided at three corners thereof. 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 a reflective anti-reflection material made of silicone rubber or the like in its peripheral area to prevent vibrations transmitted from the vibration vent 3 from being reflected at the peripheral area and returning toward the center.
It is supported by beam material 7.

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' corresponding 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.

Further, 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 the ultrasonic vibration generated by the vibrator 4 to a vibration transmission plate 8 via a horn portion 5 with a sharp tip. It shows the structure of Ben 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 in FIG. 4 is applied.

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.

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 6 and converted into detection signals that can be processed by the arithmetic control circuit 1 in the subsequent stage. Arithmetic control circuit
performs vibration transmission time measurement processing and detects the coordinate position of the vibration ben 3 on the vibration transmission plate 8.

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 1O based on the input coordinate information.

FIG. 3 shows the structure of the arithmetic control circuit l shown in FIG.

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 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 obtains timing information of a detection signal for measuring vibration transmission time for coordinate detection and signal level information for pen pressure detection from the output of the vibration sensor 6 as described later. Output. These timing and level information are input to input ports 15 and 16, respectively.

The timing signal input from the waveform detection circuit 9 is input to the input port 15, and the determination circuit 17 outputs the timing signal to the latch circuit 1.
4 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.

The output control process of the display 11° is performed via the input/output boat 18. FIG. 4 explains the detected waveform input to the waveform detection circuit 9 of FIG. 1 and the measurement process of vibration transmission time based on it. It is something. 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. The reference numeral 42 in FIG. 4 indicates the signal waveform detected by the vibration sensor 6. The plate wave used in this embodiment is a dispersive wave, so it is detected with respect to the propagation distance within the vibration transmission plate 8. The relationship between the waveform envelope 421 and the phase 422 changes during vibration transmission depending on the 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 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.
and the distance d between the vibration sensor 6 is d-Vg-tg ・"-(1)' where the vibration transmission time is tg
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 is performed based on the detection of a single phase signal.
22 specific detection points, for example, if the time from vibration application to the zero cross point after passing the peak is tp, the distance between the vibration sensor and the vibration vent is dwnΦin p+Vp@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= [(Vget g−Vp・t p)/input p+
l/N] ... (3) It is shown as follows. Here, N is a real number other than O, and an appropriate value is used. For example, if it is N-2, n can be determined within ±1/2 wavelength. n obtained as described above 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.

The two vibration transmission times tg and tp shown in FIG. 4 are measured by the waveform detection circuit 9 shown in FIG. The waveform detection circuit 9 is constructed as shown in FIG. The waveform detection circuit shown in FIG. 5 also processes level information of the output waveform of the vibration sensor 6, as will be described later, in order to detect pen pressure.

In FIG. 5, the output signal of the vibration sensor 6 is amplified to a predetermined level by a preamplifier circuit 51. The amplified signal is input to the envelope detection circuit 52, and only the envelope of the detection signal is extracted. The timing of the peak of the extracted envelope is detected by the envelope peak detection circuit 53. The peak detection signal is detected by a signal detection circuit 54 composed of a mono multivibrator, etc.
The envelope delay time detection signal Tg of a predetermined waveform is
is formed and input to the arithmetic control circuit 1.

Further, a phase delay time detection signal Tp is formed by a comparator detection circuit 58 from this Tg multiplied signal and the original signal delayed by the delay time adjustment circuit 57, and a phase delay time detection signal Tp is formed by the arithmetic control circuit l.
is input.

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 each of the envelope delay times Tgl to h1 phase delay times 'rp th-h are input to the arithmetic control circuit 1.

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 vibrator Ben. Data is taken into the latch circuit 14 without worrying about the envelope and phase delay times.

When three vibration sensors 6 are arranged at the positions 31 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 and control circuit 1 can determine the coordinates (x, y) of the position P of the vibrating vent 3 based on the linear pressures 19di to d3 using the following formula from the 3-square theorem.

X=X/2+ (dl+d2)(di-d2)/2x
...(4) y=Y/2+ (d1+d3)(d1-d3)/2
Y (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 Sl).

The position coordinates of the vibrating vent 3 can be detected in real time as described below.

According to the above configuration, since ultrasonic vibration is transmitted to the vibration transmission plate 8 as an elastic plate wave, interference caused by scratches and obstacles on the vibration transmission plate 8 is reduced, and highly accurate coordinate detection can be performed. can.

In this embodiment, as shown in FIG. 1li7, fine irregularities are provided on the surface of the vibration transmission plate 8.

In FIG. 7, reference numeral 71 indicates the lower part of the body of the vibration vent 3, and a horn portion 5 is attached to the tip by a threaded portion 76.
are combined.

The surface of the vibration transmission plate 8 is provided with fine irregularities to increase the roughness of the surface. This degree of roughness is set to a mesh number of 82,000 or higher.

By setting the roughness to this level, the transparency of the vibration transmission plate 8 will not be reduced, and the visibility of the display below it will not be reduced. Also, this surface roughness allows external light to be diffusely reflected, It is also possible to improve the visibility of the display. Furthermore, the writing quality of the vibrating ben 3 can be improved.

The uneven processing is applied not only to the surface of the vibration transmission plate 8 but also to the back side of the vibration transmission plate 8, so as to adjust the transparency of the vibration transmission plate 8 or the scattering properties of external light and display light. The vibration detection characteristics can also be improved by roughening the surface of the plate 8.

FIG. 8 shows the vibration detection waveform output by the vibration sensor 6 provided at the corner of the vibration transmission plate 8 when there is no uneven processing, and FIG. 9 shows the waveform when there is uneven processing.

If there is no uneven processing, as shown in Fig. 8, the vibration vent 3
Since the surface waves input to the vibration transmission plate 8 are combined with the transmitted vibration due to the inclination of the vibration transmission plate 8, a peak as shown by the symbol wh is generated. Depending on the detection threshold, the above-mentioned peak detection may erroneously detect a peak due to this surface wave component, resulting in an error in the vibration transmission time and, therefore, in the coordinate detection accuracy.

On the other hand, if the vibration transmission plate 8 is textured, one surface wave acid component will be attenuated by the unevenness of the vibration transmission plate 8, and a peak due to the surface wave component will not occur as shown in FIG. Accurate coordinate detection can be performed.

[Effects of the Invention] As is clear from the above, according to the present invention, vibrations input from a vibrating vent having a vibration generating means are detected by a plurality of sensors provided on the vibration transmitting plate, and the vibrations of the vibrating vent are transmitted. In a coordinate input device that detects coordinates on a board,
Since the vibration input surface of the vibration transmission plate is configured with fine irregularities, the accuracy of coordinate detection will be reduced even if the vibration ben is tilted or the pen pressure of the vibration ben is insufficient. Since the surface wave component of the vibration transmission plate can be removed, coordinate detectability can be greatly improved, and at the same time, the writing quality can be improved, and external light can be diffusely reflected, making it easier to use when installing a display at the bottom of the vibration transmission plate. This has the excellent effect of improving display visibility.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the configuration of an information input/output device adopting the present invention, Fig. 2 is an explanatory diagram showing the structure of the vibrating vent shown in Fig. 1, and Fig. 3 is an explanatory diagram showing the structure of the vibration vent shown in Fig. 1. Figure 4 is a waveform diagram showing the detected waveform to explain the distance measurement between the vibration vent and the vibration sensor, and Figure 5 is a block diagram showing the configuration of the waveform detection circuit in Figure 1. Fig. 6 is an explanatory diagram showing the arrangement of the vibration sensor, Fig. 7 is an explanatory diagram showing the surface condition of the vibration transmission plate, and Figs. 8 and 9 are respectively when the vibration transmission plate has uneven processing. FIG. 3 is a waveform diagram showing vibration detection waveforms when no 1... Arithmetic control circuit 3... Vibration vent 4... Vibrator 6... Vibration sensor 8... Vibration transmission plate 51
... #JR#I@device 15.16 ... input port 52 ... envelope detection circuit 54.58 ... signal detection circuit 59 ... A/D conversion circuit 81 ... unevenness Processing 91...Peak hold circuit

Claims (1)

[Claims] A coordinate input device that detects vibrations input from a vibration ben having a vibration generating means using a plurality of sensors provided on a vibration transmission plate to detect the coordinates of the vibration ben on the vibration transmission plate. A coordinate input device characterized in that a vibration input surface or both surfaces are provided with fine irregularities.