JPS607526A - Electronic blackboard device - Google Patents

Abstract

PURPOSE:To facilitate a design of a scan control circuit with improvement of reliability for reading the writing pressure coordinates and to attain the faithful reproduction of the writing contents, by providing a means which detects the electromotive force generated by the writing pressure to an electronic blackboard made of a polymer piezoelectric material. CONSTITUTION:A means which detects the electromotive force generated by the writing pressure is provided to an electronic blackboard made of a sheet type polymer piezoelectric material. For instance, the scan signals are transmitted to an X axis input circuit 9, a Y axis input circuit 10 and a matrix circuit 12 from a scan control circuit 11. The writing pressure coordinates on an electronic blackboard 1 are supplied to the circuit 12 via the circuits 9 and 10. The circuit 12 converts the output signals given from the blackboard 1 into data signals for each 2-bit block. These data signals are written to a memory circuit 13 by the writing signal given from the circuit 11. Then a microcomputer 18 reads the data signal out of the circuit 13 and displays the contents written on the blackboard 1 to a terminal device, a printer, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention is directed to the use of pressure possessed by a piezopolymer material to write characters and figures written on an electronic blackboard made of a piezopolymer material with a writing instrument such as a felt pen or chalk. - Utilizes electrical conversion characteristics to obtain a real-time continuous electrical signal according to the writing procedure, and then processes this electrical signal via a microcomputer so that it can be used for information transmission and hard copies. This invention relates to an electronic whiteboard device.

Prior Art Conventionally, as an input method for converting written content such as handwritten characters and figures into electrical signals, methods such as a) electromagnetic induction method and pressure-sensitive conductive sheet method have been devised. When applied to a blackboard, there are problems with the weight and cost of the input device, and the pressure-sensitive conductive sheet method requires electricity to be constantly applied to the pattern input surface in order to read the change in resistance of the pressure-sensitive conductive sheet when writing pressure is applied. This has the drawback of high power consumption.

In recent years, synthetic polymer piezoelectric/pyroelectric films typified by polyvinylidene buttride have appeared, and various transducers and sensors are being developed in terms of applications. This is an attempt to apply electronic film to electronic blackboards.

Purpose of the Invention The purpose of the present invention is to use a sheet-like polymer piezoelectric material in an electronic blackboard, and to transmit characters and figures drawn on the electronic blackboard by utilizing the pressure-electromotive force conversion characteristics of the polymer piezoelectric material. An object of the present invention is to provide an electronic whiteboard device that can be used to create or create a hard copy.

Another object of the present invention is to provide an electronic whiteboard device that facilitates the design of a scanning control circuit that generates a scanning signal for scanning an electronic blackboard.

Still another object of the present invention is to provide an electronic whiteboard device that can improve the reliability of reading pressure coordinates and faithfully reproduce handwritten content.

Structure of the Invention The electronic whiteboard device of the present invention consists of two polymer piezoelectric sheets on which metal is deposited over the entire surface on one surface and a plurality of parallel linear electrodes are deposited on the other surface at regular intervals. The metal-deposited surfaces of each polymer piezoelectric sheet are adhered to each other so that the linear electrodes of each polymer piezoelectric sheet are orthogonal to each other, a reinforcing plate is adhered to the electrode-forming surface of one polymer piezoelectric sheet, and the metal-deposited surfaces of the other polymer piezoelectric sheet are An electronic blackboard has a resin sheet constituting the writing surface adhered to the electrode-forming surface, and the linear electrodes of one of the polymer piezoelectric sheets on one side of the electronic blackboard are sequentially scanned to detect the effect of the writing pressure on the polymer piezoelectric sheet. A first input circuit detects an electromotive force, and a first input circuit detects an electromotive force developed in this polymer piezoelectric sheet by scanning the line electrode of the other polymer piezoelectric sheet of the electronic whiteboard block by block. a 2-input circuit; a matrix circuit that forms a data signal representing pen pressure coordinates using the output signals from the first and second input circuits; a storage circuit that stores the data signal from the matrix circuit; The present invention is characterized by comprising: a second input circuit, a matrix circuit, a scan control circuit that controls the memory circuit, and a microcomputer that controls the memory circuit and the scan control circuit.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is an exploded perspective view of an electronic whiteboard 1 used in the electronic whiteboard device of the present invention, and FIG. 2 is a side view of the electronic whiteboard.

This electronic blackboard 1 has a reinforcing plate 2 made of an electrically insulating material with a thickness of about 3 fins on the back surface, and a piezoelectric polymer sheet 3 made of polyvinylidene buttoxide, for example, which is made into an electret with an adhesive, on the reinforcing plate 2. Paste them together. This polymer piezoelectric sheet has two sides perpendicular to one side facing the reinforcing plate 2.
1.5m extending in the X-axis direction (X-axis and Y-axis)
A plurality of parallel in-line Y-axis electrodes Yl, Y2, . . . HYn arranged at equal intervals with a pinch of m are deposited,
Lead wires LYI, LY2, . . . LYn made of formal wires having a diameter of 0.3 fins, for example, are connected to these electrodes, respectively. A metal 4 is deposited over the entire surface of the other side of the polymer piezoelectric sheet 3.

Another polymer piezoelectric sheet 5 is further bonded to this polymer piezoelectric sheet 3. This polymer piezoelectric sheet is similar to the polymer piezoelectric sheet 3.
Metal 6 is deposited over the entire surface on one side facing the plane, and on the other side there are a plurality of parallel in-line shapes arranged at equal intervals with pinches of 1' and 5u extending in the Y-axis direction. X-axis electrodes Xi, X2 . . . Xn are deposited, and lead wires LXI, LX2 . The vapor-deposited metal 6 of the polymer piezoelectric sheet 5 is adhered to and electrically connected to the vapor-deposited metal 4 of the polymer piezoelectric sheet 3 by a soft conductive adhesive.

A lead wire 7 made of formal wire having a diameter of 0.3 mm, for example, is connected to these bonded vapor-deposited metals.

On the electrode forming surface of the polymer piezoelectric sheet 5, there is a resin sheet for leaving a record using a writing instrument such as chalk or a felt-tip pen.
For example, a Mylar sheet 8 is adhered to constitute the writing surface of the electronic blackboard 1. This mylar sheet is also intended to protect the polymer piezoelectric sheet 3.5 from being damaged during writing.

In the electronic blackboard having the above structure, when characters or figures are written on the mylar sheet 8 using chalk, for example, writing pressure is applied to the piezoelectric polymer sheets 3 and 5. This writing pressure is converted into an electromotive force developed in the polymer piezoelectric sheet due to the pressure→electromotive force conversion characteristic of the polymer piezoelectric sheet.

This electromotive force is based on the potential of the lead wires 7 connected to the vapor-deposited metals 4 and 6, and the lead wires LX'l...LXn and the lead wires LYI... connected to each X-axis electrode and Y-axis electrode, respectively. - Guided by LYn. Since the electromotive force output of the X-axis electrode and the electromotive force output of the Y-axis electrode are separated by the reference potential, they are taken out to the lead wire without causing interference with each other. As shown in Figure 3, for example, 6
40 X-axis electrodes x 1, X2...X640, 64
The electromotive force generated at the illustrated pen pressure point A on the electronic whiteboard 1 having 0 Y-axis electrodes Yl, Y2, ...YB40 is caused by the electrodes that intersect this pen pressure point, that is, the X-axis electrode X3 and the Y-axis This occurs at the electrode Y3.

In order to detect the electromotive force generated by pen pressure and analyze the pen pressure coordinates, electrical signals for scanning that are generated at regular intervals from a certain reference time are sequentially supplied to the X-axis electrode and the Y-axis electrode. If used to detect the pen pressure electromotive force generated in each electrode, the pen pressure coordinate can be read out as a time function from a certain reference time.

Now, assume that the dimensions of the electronic blackboard are approximately 1 m x 1 m, and that the number of X-axis electrodes and Y-axis electrodes is approximately 1000/1.5 dragon #640 (numbers). Here, 1.5+u is the electrode arrangement pinch, that is, the reading resolution. Further, assuming that the writing speed with a writing instrument is approximately 50 cm/sec, the writing time allocated to a unit electrode field in the X-axis direction is 1.5 mm 150 cm = 3 msec. Therefore, all 640 electrodes in the X-axis direction are
To scan at m5ec, each electrode field requires 3 m5ec/
640 # It is necessary to perform scanning in a time of 4.6 #sec.

On the other hand, in order to scan all 640 electrodes in the Y-axis direction, since the resolution is the same as in the X-axis direction, it is necessary to scan within the scanning time per unit X-axis electrode, that is, 4.6 μsec. . Therefore, the scanning time per unit Y-axis electrode is 4.6 μsec/640 #7.0 nsec.

If this scanning time is replaced with frequency, it is 1/7.0ns
ec #140MHz, which is a very high frequency. However, it is extremely difficult to perform processing using such high frequency scanning signals due to the configuration of the scanning control circuit.

Therefore, the electronic whiteboard device of the present invention takes this point into consideration,
Scanning in one direction is performed sequentially for each electrode (hereinafter referred to as sequential scanning), while scanning in the other direction is performed for each block of multiple electrodes (hereinafter referred to as block scanning). The configuration is such that the scanning frequency can be lowered to a practically appropriate frequency.

FIG. 4 is a diagram for explaining an example of blocking the Y-axis electrodes of the electronic blackboard 1 based on the above idea. In this example, 640 Y-axis electrodes Yl, Y2...YB40 are
20 blocks for every 2 lines YBI, YB2...YB
Divide into 20. The Y-axis electrodes are scanned for each of these blocks, that is, 32 blocks.

A scanning signal is supplied to each electrode. In this way, the time required to scan a unit Y-axis block is
As mentioned above, the scanning time per axial electrode was 4.6 μsec.
c, 4.6 μsec/20 = 230 nsec, which is approximately 4.4 M fiz when expressed in frequency, which is within a practical range.

The sequential scanning of the X-axis electrode and the block scanning of the Y-axis electrode are
This is performed in the X-axis input circuit 9 and Y-axis input circuit 10, which are connected to the axis electrode and the Y-axis electrode via lead wires, respectively.

Scanning of the X-axis electrode and Y-axis electrode is performed in the following order. First, the X-axis electrode x1 is scanned, and during this scanning time
The axis blocks are sequentially scanned in the order of YBI, YB2, . . . YB20. In FIG. 4, the intersections between the X-axis electrode X1 and the Y-axis electrode of each block are indicated by broken lines in blocks Bl, B2,
...B20, and shows a state in which the coordinates on the X-axis electrode Xl are scanned in the order of blocks Bl, B2, ...B20. When the scanning of the Y-axis electrode is completed, the
Moving on to the axis electrode X2, a similar scan is performed (.

Once all the electrodes on the X and Y axes have been scanned, the process returns to the beginning and repeats the same scan.

FIG. 5 shows the X-axis input circuit 9. This input circuit consists of 640 X-axis electrodes Xi, X2...X64 of the electronic blackboard.
0 (7) Lead wire LXI, LX2 --- lX64
640 input terminals IXLIX2 connected to 0...
-lX640. Since 640 circuit units having the same structure are connected in parallel to these input terminals, the circuit unit connected to input terminal IXI will be described as a representative example.

A phase inversion amplifier AXI is connected to the input terminal IXI,
A feedback resistor R is connected between the input terminal and output terminal of this amplifier.
XI is connected. The output terminal of amplifier AXI is connected to one input terminal of gate circuit GXI, and the other input terminal of this gate circuit is connected to X-axis scanning signal input terminal SX.
Connected to I. Gate circuit GX2. GX3 ・
...Each other input terminal of GX640 is an X-axis scanning signal input terminal SX2. SX3: Each is connected to 5X640.

FIG. 6 shows the Y-axis input circuit 10. This input circuit is
20111i1 Y-axis electrode block YBI of electronic blackboard,
YB2...20 with the same structure corresponding to YB20
Since the circuit section CLC2...C20 is configured, the circuit section C1 will be described as a representative example. This circuit section connects the lead wires LYI, L of the Y-axis electrodes Yl, Y2, Y2, ..., Y32 of the Y-axis electrode block YBI of the electronic blackboard.
Y2 ・ ・ ・32+[lil connected to LY32
The input terminals IYI, IY2, . . . IY32 are provided. These input terminals are connected to phase inverting amplifiers AYI, ΔY.
2...AY32 are connected respectively, and feedback resistors RYI and RY are connected between the input terminal and output terminal of these amplifiers.
2...RY32 are connected respectively. The output terminals of these amplifiers are gate circuits GY1, GY2...
- They are each connected to one input terminal of GY32, and the other input terminals of these gate circuits are commonly connected to the Y-axis block scanning signal input terminal 5YBI.

Other circuit sections C2...C20 are shown only as blocks to simplify the drawing, but similarly, the input terminals IY33-1
Y64. - ・-, IY609 to IY640, amplifiers AY33 to AY64.・-・, AV609 ~AY
640, gate circuits GY33 to GY64. ...,
Consists of GY609 to GY640 (not shown),
And Y-axis block scanning signal input terminal 5YB2...5
Each is connected to YB20.

FIG. 7 shows X-axis scanning signals PXI, PX2 . . . PX6 which are sequentially supplied to the X-axis scanning signal input terminals SXI, SX2 .
40 is shown. These X-axis scanning signals are pulse signals whose duration is 1, which is the time required to scan each X-axis electrode.
．． That is, it is equal to 4.6 μsec. These pulses are
These pulses occur continuously, with the next pulse rising at the time the previous pulse falls. In the figure, the pulse on the -tongue is the scanning reference clock, which occurs every 3m5eC and is 0.5
It has a duration of μsec. This reference clock starts one scan of all the X-axis electrodes and all the Y-axis electrodes of the electronic blackboard.

FIG. 8 shows a Y-axis block scanning signal PYBI that is sequentially supplied to the Y-axis block scanning signal input terminals SYI, SY2, . . . , 5Y20 of the Y-axis input circuit 10 of FIG.

PYB2... Indicates PYB20. These Y-axis block scan/failure signals are pulse signals whose duration is equal to the time required to scan each Y-axis electrode block YBI, YB2, . . . YB20, ie, 230 nsec. These sequential pulses occur in succession, with the next pulse rising at the time the previous pulse falls.

In the figure, the pulse on the tongue indicates one of the X-axis scanning signals with a duration of 4.6 μsec.

Next, scanning of the grid-like electrode group of the electronic whiteboard 1 will be explained based on FIGS. 4 to 8. Polymer piezoelectric sheet for electronic blackboard 3
The electromotive force generated by the pen pressure during 5 and 5 is supplied to the X-axis input circuit 9 and the Y-axis input circuit 10 through lead wires from the X-axis electrode and the Yi# electrode, respectively. The electromotive force supplied to the input terminals IXLH2...1X640 of the X-axis input circuit 9 is applied to the amplifier A as 1. AX2...Amplified by phase inversion by AX640, gate circuit GXI,
GX2...-GX640 (7) Supplied to one input terminal. On the other hand, the other input terminals of these gate circuits include X-axis scanning signal input terminals SXI, SX2 - . . . 5X
640, the X-axis scanning signals PXI and PN shown in FIG.
2...PX640 is sequentially supplied.

That is, the input terminal SXI receives the scanning signal PXI, the input terminal SX2 receives the scanning signal PX2, and the single-person terminal 5X6.
40 is supplied with a scanning signal PX640. The gate circuit is open while the scanning signal is applied. Therefore, the input terminal IXL IX2 of the X-axis input circuit 9...lX640
When the scanning signal is on, these gate circuits output their output terminals OXI, OX2 only if there is a pen pressure emf at
...Generates an output signal at 0X640.

In this way, it is possible to detect which X-axis electrode is generating an electromotive force.

While one of the X-axis electrodes is being scanned in the X-axis input circuit 9, that is, during 4.6 μsec, the Y-axis input circuit 10 performs block scanning of the Y-axis electrodes. Input terminal IY of each circuit section CLC2...C20 of the Y-axis input circuit
I, IY2...The electromotive force supplied to IY640 is
Amplifiers ΔYl, AY2 ... ^Y640 amplify the phase, and gate circuits GYI, GY2 ・
...Supplied to one input terminal of GY640. -force,
The other input terminal of these gate circuits is connected to each circuit section CI.
, C2...C20, through the Y-axis block scanning signal input terminals 5YBI, 5YB2...5YB20,
Y-axis block scanning signals PYBI and PYB2 shown in FIG.
...PYB20 is supplied in order. Looking at the circuit section C1, there are 32 gate circuits GYI, GY2...
・Block scanning signal PYBI to all GY32 simultaneously
is supplied. These 32111 gate circuits are open while the block scanning signal PYBI is supplied. Therefore, the input terminals IYI, IY2...IY of the circuit section C1
, 32, and when the Y-axis block scan signal is on, these gate circuits generate output signals at their output terminals OYI, OY2, . . . , 0Y32. By sequentially performing the above operations for the circuits C2, C3, .

In this way, scanning of the YilII electrode is performed for each block of 32 Y-axis heavy poles, that is, in units of 32 focus points. As described above, all X within the time of 3m5ec
One scan of the axis electrodes and all Y-axis electrodes is completed and the next scan is started with the next reference Cronk.

FIG. 9 shows the electronic whiteboard 1, the X-axis input circuit 9,
1 is a block diagram showing the overall configuration of an electronic whiteboard device of the present invention including a Y-axis input circuit 10. FIG. The scanning signal to the X-axis input circuit 9 and the block scanning signal to the Y-axis input circuit 10 are as follows.
Each is supplied from the scan control circuit 11.

The output signals from the X-axis input circuit 9 and the Y-axis input circuit 10 are real-time continuous electrical signals according to the writing procedure,
The signal is supplied to the matrix circuit 12.

As mentioned above, the output signal from the Y-axis input circuit is 32
Supplied in bits. This matrix circuit is
From the output signal from the axis input circuit 9 and the output signal from the Y-axis input circuit 10, a data signal for each block with a 32-bit configuration is formed that represents the pen pressure coordinate on the electronic blackboard as a time function from a certain reference time. do. Therefore, the matrix circuit has a function of organizing a large number of input lines into a time array.

This data signal from the matrix circuit is sent to the storage circuit 1
3, but this writing is performed by the scan control circuit 1.
This is done by the write signal from 1.

Since writing is performed in units of 32 bits, the write signal can be formed from the Y-axis block scanning signal.

FIG. 10 shows a write signal generation circuit 14 provided within the scan control circuit 11 to generate this write signal. This circuit uses Y-axis block scanning signals PYB1. P
YB2...Input terminal I to which PYB20 is sequentially supplied
WI, IW2...1 W2O are provided, and phase inversion amplifiers AWL, AW2...1 and 0 are connected to these input terminals, respectively. The output terminals of these amplifiers are
The capacitors CI, C2, . The output terminal of the AND gate 15 is connected to a monostable multivib break 17 via a delay circuit 16.

In the write signal generation circuit 14 having the above configuration, the block scanning signal FBI is supplied to the input terminal IWI, the block scanning signal PB20 is supplied to the input terminal IW2, . Amplifier sieve 1. Static 2... Each of the static 2o receives an amplification effect of phase inversion. In AND game 5,
Since the power supply voltage Vcc is supplied through the resistors R1, R2, . . . R20, the input terminal of the AND gate is at a high level, and its output is also at a high level. When the falling edge (corresponding to the rising edge before phase inversion) of the phase-inverted Y-axis block scanning signal PYBI arrives,
As a result of the instantaneous discharge of the capacitor, the input terminal of the AND gate 15 connected to the capacitor CI becomes low level, and as a result, the output of the AND gate becomes low level.

Thereafter, capacitor C1 is charged via resistor R1, and when the input terminal of AND gate 15 connected to capacitor C1 returns to high level, the output of AND gate 15 also returns to high level. Therefore, AND gate 1
5 generates a trigger pulse in response to the rising edge of the Y-axis block scan pulse PYBI. The above operation is performed by sequentially supplied Y-axis block scanning signals PYB2. P.Y.B.
3...The same process is performed for PYB20.

In this way, the trigger pulse train generated at the output terminal of the AND gate 15 is sent to the delay circuit 16 at a frequency of 100 to 120. n5ec
The signal is delayed by a certain amount of time and is supplied to the monostable multi-high break 17. A monostable multivibrator generates a single square pulse each time a trigger pulse is applied, which becomes the write signal to the storage circuit. The write signal is 100ns
ec duration. FIG. 11 shows these write signals WSI, WS2, . . . , WS20 together with the corresponding pro-7 scan signals.

In FIG. 9, these write signals are
A data signal is written in each coordinate block to a storage position on a virtual blackboard formed by storage elements.

Reading of data from the storage circuit 13 for which writing has been completed is performed under the control of the microcomputer 18. The data signal read from the memory circuit is sent to a terminal device, a printer, etc., and the written content can be displayed on the electronic blackboard. In the read operation from the storage circuit, the signal system prepared in the software of the microcomputer can be of two types necessary for driving each terminal device of the serial data input format and the parallel data input format. Since the serial data input system is equipped with a transmission function using a telephone line, it is possible to prepare a signal having a specified compression ratio. A parallel data input system can facilitate input to a general purpose computer as a 32-bit structured signal.

Further, other signals necessary for reading, such as a read command and a read timing signal, can be provided in each signal system. In the electronic whiteboard device shown in FIG. 9, the microcomputer 18 not only controls reading from the memory circuit 13, but also controls writing to the memory circuit 13, controls the scanning control circuit 11, controls terminal equipment, and controls the reference time axis. It is also something that is done.

Although the electronic whiteboard device of the present invention has been described above based on one embodiment, those skilled in the art will of course be able to make various changes and modifications within the scope of the present invention.

For example, since the Y-axis electrodes are operated in units of 32 bits, the number of Y-axis electrodes should be set to a multiple of 64 so that there are no remaining bits.
Although the number of Y-axis electrodes is set to 0, even if the number of Y-axis electrodes is such that surplus bits appear, there is no problem with the operation for detecting pen pressure coordinates.

Further, in the above embodiment, the X-axis electrodes were sequentially scanned and the Y-axis electrodes were scanned in blocks, but it is obvious that the X-axis electrodes may be scanned in blocks and the Y-axis electrodes sequentially scanned.

The number of electrodes to be divided into blocks can be any number as long as it can be selected so as to obtain a practically appropriate scanning frequency when designing the scanning control circuit.

Effects of the Invention Since the electronic whiteboard device of the present invention utilizes the pressure-electromotive force conversion characteristics of a sheet-shaped polymeric piezoelectric material, it is easier to detect pen pressure coordinates on an electronic whiteboard than with a conventional pressure-sensitive conductive sheet method. In this case, there is no need to apply current to the grid-like electrodes with scanning signals, so power consumption can be reduced and safety can also be improved.

Furthermore, since a sheet-like inexpensive polymeric piezoelectric material is used, weight and cost can be reduced compared to conventional electromagnetic induction methods.

In addition, when scanning the electrodes of an electronic blackboard, the X-axis electrode or the
Since the axial electrodes are divided into blocks and each block is scanned, the necessary scanning frequency can be kept within a practical range in relation to the scanning control circuit.
It becomes easy to design and manufacture a scan control circuit without degrading the reading function.

Furthermore, since the scanning frequency can be reduced, high-frequency leakage caused by distributed capacitance existing between electrodes can be reduced (and the phase shift of high-frequency current can be reduced, and amplifiers with high input circuits can be This provides advantages such as being able to utilize

Therefore, according to the electronic whiteboard device of the present invention, the reliability of the writing pressure coordinate reading function is improved, and the written content can be faithfully reproduced.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of an electronic blackboard used in the electronic whiteboard device of the present invention, FIG. 2 is a side view of the electronic blackboard shown in FIG. 1, and FIG.
Figure 4 is a diagram for explaining the pen pressure coordinates of the electronic blackboard. Figure 4 is a diagram for explaining the programming of the Y-axis electrode of the electronic blackboard. Figure 5 is a diagram showing the X-axis input circuit. Figure 6 is a diagram showing the Y-axis input circuit, Figure 7 is a waveform diagram of the X-axis scanning signal, Figure 8 is a waveform diagram of the Y-axis block scanning signal, and Figure 9 is:
FIG. 10 is a block diagram showing the configuration of the electronic blackboard device. FIG. 10 is a diagram showing a write signal generation circuit. FIG. 11 is a waveform diagram showing the write signal. 1...Electronic whiteboard 2...Reinforcement plate 3.5...Polymer piezoelectric sheet 4.6...Vapour-deposited metal 7...Lead wire 8...Mylar sheet 9...X-axis input circuit 10...Y-axis input circuit 11)...Scan control circuit 12...Matrix circuit 13...Memory circuit 14...・Write signal generation circuit 15...AND gate 16...Delay circuit 17...Monostable multi-bi break 18...
・Microcomputer , I gate...Input terminal OX, OY...Output terminal AX, AY, ■...Phase inversion amplifier GX, GY...Gate circuit SX...X-axis scanning signal input terminal SYB... Y-axis block scanning signal human power U111 child. Figure 1 1 /- Figure 2 Figure 1 Figure 4 Figure 10 Figure 11 Procedure 111 Official Book July 23, 1958 Mr. Kazuo Wakasugi, Commissioner of the Patent Office■, Minor Case Display 1988 Patent Application No. 114.359 No. 2, Name of the invention Electronic whiteboard device 3, Relationship with the person making the amendment Patent applicant name Nichigaku Co., Ltd. Japan Synthetic Rubber Co., Ltd. 4, Agent 110 Address 1-27 Taito, Taito-ku, Tokyo No. 11 No. 5, Detailed description of the invention in the specification subject to amendment
The polymer piezoelectric sheet used in the present invention is preferably an electret polyvinylidene butylene sheet, but other polymer piezoelectric sheets may also be used, such as polymers with a high dielectric constant, specifically polyvinylidene butylene, It may also be a sheet of a composite material of polymer and ceramics, such as nitrile rubber or chloroprene mixed with piezoelectric ceramic powder. (2) Figure 6 of "Drawing" is corrected as shown in the attached sheet.

Claims (1)

[Scope of Claims] 1. Two polymer piezoelectric sheets on which metal is entirely vapor-deposited on one surface and a plurality of parallel line-shaped electrodes are vapor-deposited on the other surface at regular intervals, The metal-deposited surfaces of each polymer piezoelectric sheet are adhered to each other so that the line electrodes are perpendicular to each other, a reinforcing plate is adhered to the electrode formation surface of one polymer piezoelectric sheet, and the electrode is formed on the other polymer piezoelectric sheet. An electronic blackboard with a resin sheet constituting the writing surface adhered to the surface, and a linear electrode of a polymer piezoelectric sheet on one side of the electronic blackboard are sequentially scanned to measure the electromotive force developed in this polymer piezoelectric sheet due to writing pressure. and a second input circuit that scans the linear electrodes of the other polymer piezoelectric sheet of the electronic whiteboard block by block to detect the electromotive force developed in the polymer piezoelectric sheet by pen pressure. a matrix circuit 1 that forms a data signal representing pen pressure coordinates based on the output signals from the first and second input circuits; a memory circuit that stores the data signal from the matrix circuit; An electronic whiteboard device comprising: a scan control circuit that controls a two-input circuit, a matrix circuit, and a memory circuit; and a microcomputer that controls the memory circuit and the scan control circuit.