JPH02128211A - Coordinate input device - Google Patents

Abstract

PURPOSE:To simplify constitution and to improve assembly by coupling a vibration transmission board and a vibration sensor through a conductive material and electrically grounding either of the vibration transmission board or the vibration sensor. CONSTITUTION:The coupling surface of the vibration transmission board 8 with the vibration sensor 6 consists of a conductive part 62, and the vibration sensor 6 and the vibration transmission board 8 are coupled by the conductive material, conductive grease 61, for example. Since the vibration transmission board 8 and the vibration sensor 6 are coupled through the conductive material, either the vibration transmission board 8 or the vibration sensor 6 can electrically be grounded. Thus, the constitution of a device is simplified and assembly 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, to a vibration transmitting plate using a vibration sensor provided on the vibration transmitting plate. The present invention relates to a coordinate human-powered device that detects the coordinates of an input point.

[Prior Art] Coordinate input devices using various input pens, tablets, etc. have been known as devices for manually 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 manually applied to a vibration transmission plate, detected by vibration sensors installed at predetermined locations on the vibration transmission plate from the input point, and transmitted to each sensor. A configuration is known in which the coordinates of an input point are determined based on the transmission time.

In this type of method that uses ultrasonic vibration, the input tablet can be constructed not only from transparent materials such as acrylic plates and glass plates, but also from conductive materials such as metal, so it is possible to place the input tablet on top of a liquid crystal display, etc. Therefore, it is possible to construct an information input/output device that is easy to operate and can be used as if an image was written on a piece of paper. Moreover, even if it is a normal opaque tablet, an information input device can be constructed easily and inexpensively without using patterned electrodes.

[Problems to be Solved by the Invention] In the coordinate input device as described above, a piezoelectric element or the like is used as an electric/mechanical or mechanical/electrical conversion element constituting the vibrator or vibration sensor. Such a vibration conversion element is fixed to a member such as a vibration transmission plate of a tablet or a horn at the tip of a photographing pen by a method such as adhesion or pressure contact.

In pressure welding using a spring or the like, an air layer is created between the end face of the element and the surface to which it is pressed due to the roughness of the end face of the element, and even if the pressure welding conditions are controlled, variations in vibration transmission characteristics still occur. In particular, since electrodes are provided on the end face of the conversion element,
In a structure in which silver paste or the like is adhered, it is difficult to control the shape of the end face uniformly, so the vibration transmission characteristics vary widely.

Therefore, in the method of determining the photographing detection timing based on waveform processing and performing coordinate calculation, there is a problem in that errors occur in the detected coordinate values, making it impossible to ensure constant coordinate detection accuracy for each product.

Changes in vibration transmission characteristics occur at the pressure contact area of the vibrator of the vibrating pen and the pressure contact area 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 will be Quite large variations in characteristics occur.

Therefore, it has been proposed to fill the space between the vibration transmission plate and the vibration sensor with grease in order to reduce the variation in characteristics at the pressure welding part. for vibration sensor,
Each vibration transmission plate must be dropped to the ground of the case through a separate route, which complicates the configuration, resulting in poor assemblability of the device and increased costs.

The object of the present invention is to solve the above problems.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, the vibrations input from the vibrating pen to the vibration transmission plate are detected by a vibration sensor provided on the vibration transmission plate, and the vibrations of the vibrating pen are detected. In the *S input device that detects the coordinates of an input point, the coupling surface of the vibration transmission plate with the vibration sensor is made of a conductive material, and the vibration sensor and the vibration transmission member are connected to each other through the conductive material. A combined configuration was adopted.

[Function] According to the above configuration, since the vibration transmission plate and the vibration sensor are coupled through the conductive material, either the vibration transmission plate or the vibration sensor may be electrically grounded.

[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 device shown in FIG. The input image is displayed on a display 11' consisting of a CRT placed over the input tablet according to the information.

In the figure, the reference numeral 8 is a vibration transmitting plate made of acrylic, glass, etc., which transmits the vibration transmitted from the vibrating pen 3 to three vibration sensors 6 provided at its corners. Now, 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, the coordinates of the vibrating pen 3 on the vibration transmitting plate 8 are detected.

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 arranged on a display 11' capable of displaying dots, such as a CRT or a liquid crystal display, and displays a dot at a 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 an image composed of elements such as points and lines inputted by the vibrating pen 3 is displayed as if it were written on paper. Appears after the trajectory of the vibrating pen as if it were done.

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 portion 5 having a sharp tip.

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

A vibrator 4 built into the vibrating pen 3 is connected to a vibrator drive circuit 2.
driven by. The drive signal for the vibrator 4 is supplied as a low-level pulse signal from the arithmetic and control circuit 1 shown in FIG. is applied to

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 section 5.

The vibration frequency of the vibrator 4 is selected to a value that can generate plate waves in the vibration transmission plate 8. 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. 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.

On the other hand, the ultrasonic vibrations transmitted on the vibration transmission plate 8 are input to the vibration sensor 6 provided at the end of the vibration transmission plate 8, and are converted into an electric signal again. 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 vibration sensor 6 of the vibration transmission plate 8 is pressed against the vibration transmission plate 8 by a pressing load f such as a spring, rather than by adhesion.

At this time, the vibration sensor 6 is pressed into contact with the vibration transmission plate 8 via the conductive grease 61. This conductive grease 61 is
A material with a consistency of about 190 to 390 (JISK2220) is used. By attaching the conductive grease 61 to the pressure contact surfaces of the vibration sensors 6 when they are brought into pressure contact,
It is filled between the vibration sensor 6 and the vibration transmission plate 8.

According to such a structure, the vibration sensor 6 and the vibration transmission plate 8
The conductive grease 61 is filled into the space that was conventionally created due to surface roughness, deformation, etc. of the press-contact surfaces between the two, and the substantial vibration transmission surfaces of the two can be brought into complete contact without creating an air layer. . Therefore, ultrasonic vibrations can be efficiently transmitted from the vibration transmission plate 8 to the vibration sensor 6, and efficient energy conversion is possible. That is, the amplification factor after detection by the vibration sensor 6 can be reduced, and power consumption can be reduced.

Further, since there is no variation in the degree of contact between the vibration sensor 6 and the vibration transmission plate 8 for each product, it is possible to eliminate variation in coordinate detection accuracy in coordinate detection processing based on waveform processing, which will be described later. Vibration sensor 6, vibration transmission plate 8
The member to be interposed on the pressure contact surface is not limited to conductive grease, and compounds having similar consistency and conductivity or other high-consistency fluids may be used.

Further, in order to prevent noise and the like, a conductive portion 62 provided for erasing static electricity on the vibration transmission plate 8 is grounded through conductive grease 61 to a common ground line with the vibration sensor 6. It goes without saying that the conductive portion 62 may be not only the portion near the vibration sensor 6 but also the entire portion if it is made of a transparent material such as ITO.

In addition, although conductive grease was exemplified above as the material interposed between the vibration transmission plate 8 and the vibration sensor 6, this material may also be a conductive adhesive or the like. In this case, the pressure contact mechanism This eliminates the need for the device, making the configuration of the device simpler and cheaper.

Referring again to FIG. 1, the vibration sensor 6 provided at the corner of the vibration transmission plate 8 is also constituted by a mechanical/electrical transducer such as a piezoelectric element. The output signals of each of the three vibration sensors 6 are input to the signal waveform detection circuit 9, and are converted into detection signals that can be processed by the arithmetic control circuit 1 at the subsequent stage. The arithmetic control circuit 1 performs measurement processing of vibration transmission time, and
The coordinate position on the vibration transmission plate 8 is detected.

The detected coordinate information of the vibrating vent 3 is processed in the arithmetic control circuit 1 according to the output method by the display 11'. That is, the arithmetic control circuit displays the display tt via the video signal processing circuit 10 based on the input coordinate information.
' controls the output behavior of '.

FIG. 3 shows the structure of the arithmetic control circuit 1 shown in FIG.

Here, we will mainly focus on the drive system of the vibration vent 3 and the vibration sensor 6.
The structure of the vibration detection system is 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 signal 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. These timing information are each input to the input boat 15.

The timing signal input from the signal waveform detection circuit 9 is input to the input port 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 calculations are 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 the microcomputer 11
to be notified.

The output control process of the display 11' is performed using input/output port 1.
This is done via 7.

FIG. 4 explains the detected waveform input to the signal waveform detection circuit 9 of FIG. 1 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. The ultrasonic vibrations transmitted from the vibration ben 3 to the vibration transmission plate 8 driven by such a waveform are transmitted to the vibration transmission plate 8.
It passes through the inside and is detected by the vibration sensor 6.

After traveling within the vibration transmission plate 8 for a time t<b>2 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, and therefore the relationship between the envelope 421 and phase 422 of the detected waveform 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, focusing only on the envelope 421, its velocity is Vg, and when a point on a particular waveform, for example a peak, is detected as indicated by the reference numeral 43 in FIG. is the vibration transmission time tg, a = v g −t g ・・
(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.

In order to determine even more precise coordinate values, the phase waveform 42 in FIG. 4 is processed based on the detection of the phase signal.
2 specific detection point, for example, if tp is the time from vibration application to the zero crossing point after passing the peak, then the distance between the vibration sensor and the vibration ben is d=n ・λp+vp −tp ・
... (2) becomes. 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) /λpal
[C]... (3) It is shown as follows. Here, N is a real number other than 0, and by using an appropriate numerical value such as 0, for example N-2, n can be determined if it is within ±1/2 wavelength.

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 signal 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 peak timing 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 manually inputted to the arithmetic control circuit 1.

Further, 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 5f, and is manually inputted to the arithmetic control circuit 1.

That is, the Tg multiplied signal is converted into a pulse of a predetermined width by the monostable multivibrator 55. Further, the comparator level supply circuit 56 forms a threshold value for detecting the tp flaw signal according to this pulse timing. As a result, the comparator level supply circuit 56 is supplied with reference numeral 4 in FIG.
form a signal with a level and timing like 4,
The delay time adjustment circuit 57 is manually operated.

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 TPI-h are manually input to the arithmetic control circuit 1.

In the arithmetic control circuit of FIG. 3, the above Tgl~h, Tp1~
The input signal H 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 vibration ben. The latch circuit 14 takes in data indicating the respective delay times of the envelope and the phase.

When the three imaging 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 path 11dl to d3 to the position of the vibration sensor 6 can be determined.

Furthermore, the arithmetic control circuit 1 calculates the coordinates (X) of the position P of the vibrating ben 3 based on this straight path [idl~d3.

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

x=X/2+ (d 1 + d 2) (d 1-d
2)/2X...(4) yegY/2+ (dl+d3)(di-d3)/2Y・
... (5) Here, X%Y is the horn part 5 at the position of S2, 33 and the origin (
X% of the sensor at position 31) is the distance along the Y axis.

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

In addition, in the above example, since it is arranged on the display 11',
Although an example has been shown in which the vibration transmission plate 8 is made of a transparent material, it goes without saying that the vibration transmission plate 8 may be opaque, and the vibration transmission plate 8 without the display 11' may be made of a conductive material such as metal. The electrically conductive portion 62 is not required,
The vibration transmission plate 8 or the vibration sensor 6 may be directly grounded.

[Effects of the Invention] As is clear from the above description, according to the present invention, the vibration input from the vibrating pen to the vibration transmitting plate is detected by the vibration sensor provided on the vibration transmitting plate, and the vibration input point of the vibrating pen is detected by the vibration sensor provided on the vibration transmitting plate. In the coordinate input device that detects the coordinates of the vibration transmitting plate, the coupling surface of the vibration transmitting plate with the vibration sensor is made of a conductive material, and the vibration sensor and the vibration transmitting member are coupled via the conductive material. Since the vibration transmission plate and the vibration sensor are connected through a conductive material, it is only necessary to electrically ground either the vibration transmission plate or the vibration sensor, so the configuration of the device can be changed. It has the excellent effects of being simplified, improving assembly efficiency, and reducing manufacturing costs.

[Brief explanation of the drawing]

341 is an explanatory diagram showing the configuration of a coordinate input device adopting the present invention, FIG. 2 is an explanatory diagram showing the structure of the vibration input/output section of FIG. 1, and FIG. 3 is an explanatory diagram showing the structure of the vibration input/output section of FIG. 1. FIG. 4 is a waveform diagram showing the detected waveform explaining distance measurement between the vibrating pen and the vibration sensor, and FIG. 5 is a block diagram showing the configuration of the waveform detection circuit in FIG. 1. 6 are explanatory diagrams showing the arrangement of vibration sensors. 1... Arithmetic control circuit 2... Vibrator drive circuit 3.
... Vibration pen 4 ... Vibrator 5 ... Horn part 6 ... Vibration sensor 7 ... Anti-reflection material
8... Vibration transmission plate 9... Signal waveform detection circuit 11... Microcomputer 13... Counter 14... Latch circuit 15.
... Input port 16... Judgment circuit Figure 4 of the seventh letter

Claims (1)

[Scope of Claims] 1) A coordinate input device that detects vibration input from a vibrating pen to a vibration transmission plate by a vibration sensor provided on the vibration transmission plate, and detects the coordinates of a vibration input point of the vibration pen. A coordinate input device characterized in that a coupling surface of the transmission plate with the vibration sensor is made of a conductive material, and the vibration sensor and the vibration transmission member are coupled via the conductive material. 2) A means for press-contacting the vibration sensor to the vibration transmission plate is provided, and a highly consistent and conductive material is interposed between the vibration transmission plate and the vibration sensor.
Coordinate input device as described in Section. 3) The coordinate input device according to claim 1, wherein the vibration sensor is coupled to the vibration transmission plate using a conductive adhesive.