JPS5848949B2 - Information on the use of the product - Google Patents

Description

Description: The present invention relates to an information input device using an electrostatic coupling type tablet, and more particularly to an information input device capable of reducing communication interference caused by scanning pulses that drive the tablet.

In a conventional information input device using a capacitive coupling type tablet, once the power switch is turned on, a driving pulse is applied to the tablet regardless of whether it is being used or not. For example, the driving pulse emitted from the surface of the tablet is
This could cause interference with radio communications, especially in the shortwave band, by creating noise.

SUMMARY OF THE PRESENT EMBODIMENT In view of the above-mentioned drawbacks, the present invention provides an information input device which can extremely shorten the time of radiation of induced noise from a tablet and can virtually eliminate communication interference with other electrical products.

An embodiment of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration, and FIG. 2 is a timing chart showing signals appearing in the electric circuit of FIG.

Reference numeral 1 denotes a tablet, on which two sets of conductor groups are arranged at intervals along coordinate axes, and codes consisting of letters, symbols, etc. are set in correspondence with the coordinates.

The conductors are then provided with a scanning signal in a known manner, but in accordance with the invention, the scanning signal is provided as follows.

That is, a clock pulse a outputted from a reference pulse generator 2 is counted by a counter 4 via a gate 3 which is opened by an on signal b of a switch SW built in a sensing pen 8 and a negation signal m of a data detection completion signal m from a control circuit 9 (described later), and is made into parallel output pulses by decoders 5 and 6 which are supplied as sequential scanning pulses to each conductor of the tablet 1.

Here, the switching circuit 7 receives a signal generated by the counter 4 counting a predetermined value, and in response thereto, the X-decoder 5, the Y-decoder 6 and the control circuit 9 relatively switch from the X-direction scanning mode to the Y-direction scanning mode.

Therefore, in this case, if the signal detecting pen 8 is to pink up the scan number from a key position on the tablet 1 which is formed, for example, by the Pth conductor in the X direction and the qth conductor in the Y direction, when the counter 4 indicates the count value p, that is, when a pulse signal is supplied from the X decoder 5 to the pth conductor in the X direction, a first signal Xp in the X direction is detected from the signal detecting pen 8 and this signal is input to the control circuit 9.

This pattern is repeated alternately in the X and Y directions, and in the present invention, two X and two Y signals are picked up from one coordinate position. Before describing this operation, for convenience of explanation, the control circuit 9 will be described first.

When the control circuit 9 receives the first signals of X and Y, the control circuit 9 controls the X data register 11 and the Y data register 14.
A latch signal ef for storing the count value of the counter 4
and supplies comparison signals g and h for making the X comparator circuit 10 and the Y comparator circuit 13 compare the count values stored in the X data register 11 and the Y data register 14, respectively, with the count value of the counter 4 at that time when the second signals X and Y are received.

Then, it receives a match signal kl indicating a match from the X comparison circuit 10 and the Y comparison circuit 13, and generates a data detection completion signal m accordingly.

The control circuit 9 is also supplied with a switching signal from the X, Y switching circuit 7 .

Therefore, the control circuit 9 determines that the X-direction first signal
If so, the control circuit 9 supplies an X latch signal e to an X data register 11, in which the count value p of the counter 4 is stored.

Furthermore, the counter 4 continues to count, and when the scanning of the conductors in the X direction is completed and the counter overflows, an end signal is sent from the counter 4 to the switching circuit I, and the output of the switching circuit 7 is switched from the X-decoder 5 to the Y-decoder 6.

Therefore, the Y decoder 6 sends a scanning pulse to the conductor group in the Y direction, and when the counter 4 indicates a count value q, the signal detection pen 8 outputs a first signal Yq in the Y direction from the q-th conductor in the Y direction. This signal controls the control circuit 9.
is detected by the input signal from the switching circuit 7.
It is determined that the direction signal Yq has been detected from the Y-axis conductor, and a Y latch signal f is sent to the Y data register 14, where the count value q of the counter 4 is stored.

In this manner, data in the X and Y directions are stored, but these data are not output until the same data is input again by a similar operation.

Next, the operating state when the same data is input again will be described. The count of the counter 4 continues to count up and overflows, causing the output of the switching circuit 7 to operate the X-decoder 5 again, thereby supplying a scanning pulse to the X-direction conductor group.

As a result, the signal detection pen 8 detects the X-axis from the p-th conductor in the X-axis direction.
The second signal Xp of the X direction is picked up, which is supplied to the control circuit 9 in the same manner as the first signal Xp, and the control circuit 9 outputs the second signal Xp of the X direction.
p, and supplies an X-direction comparison signal g to the X comparison circuit 10. This X comparison circuit 10 compares the X data i stored in the X data register with the count value of the counter 4 at the time of detection of the X-direction second signal Xp, and if they match, an X match signal k is sent to the control circuit 9.

Here, the first signal Xp or the second signal X
If p is not input from the desired conductor, for example if it is erroneous data such as a power frequency signal, then the two data will not match and no match signal will be sent.

When the counter 4 counts further and overflows, the output of the switching circuit 7 is converted to the Y direction,
A scanning pulse is supplied from the Y decoder 6 to the group of conductors in the Y direction, and a second signal Y'q in the Y direction is input to the signal detecting pen 8 from the q-th conductor in the Y direction.

This second signal Y'q in the Y direction is input to the control circuit 9 in the same manner as the first signal yq in the Y direction.

The control circuit 9 judges that the signal is the second signal in the Y direction and sends a Y comparison signal h to a Y comparison circuit 13 .

As a result, the Y comparator circuit 13 compares it with the count value q of the counter 4, and if they match, a Y match signal l is input to the control circuit 9.

If they do not match, the Y match signal l is not output, just like in the X direction.

The control circuit 9 outputs a data detection completion signal m only when output signals are obtained from both the X match signal k and the Y match signal l.
When this data detection completion signal m is input to the X output gate 12 and the Y output gate 15, each gate opens, and the data of the stored value p of the X data register 11 and the stored value q of the Y data register 14 are output through the X output gate 12 and the Y output gate 15, respectively.

The data thus output is sent to an external device such as a puncher or a computer.

The data detection completion signal m of the control circuit 9 causes the X output gate 12 and the Y output gate 15 to output the stored values of the X data register 11 and the Y data register 14, respectively, and also causes the switch SW
remains on, the gate circuit 3 is turned off, and the clock pulse a from the reference pulse generator 2 is not supplied to the counter 4.

However, no scanning pulse is supplied to tablet 1.

In order to resume detection, the switch SW built in the detection pen 8 is turned off once, and the data detection completion signal m
This can be done by turning on the switch SW built in the detection pen 8 again in the reset state.

The data detection completion signal and the X.Y latch signal are
This can be done by an end signal or the like from an external device (not shown) which receives the signals output from the output gate 12 and the Y output gate 14 .

Since the present invention is configured as described above, drive pulses are not constantly supplied to the tablet, which means that communication interference with other electrical products can be virtually eliminated, power consumption in the scanning means can be reduced, and malfunction prevention can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.
Fig. 2 is a timing chart showing signals appearing in the electric circuit of Fig. 1. 1: tablet, 2: reference pulse generator, 3: gate circuit, 4: counter, 5, 6: decoder, 7: X, Y switching circuit, 8: detection pen, 9: control circuit, 10, 13:
Comparison circuit, 11, 14: Data register, 12, 15:
Output gate, C: scanning pulse from the counter, m: data detection completion signal.

Claims (1)

[Claims] 1. An information input device having a tablet having two sets of conductor groups arranged at a distance along the coordinate axes, scanning means for supplying scanning signals alternately and repeatedly to each of the conductor groups, an indication pen including a switch which becomes conductive when brought into contact with the tablet and which detects the scanning signal from a desired position on the tablet while the switch is on, and a control circuit which generates a command signal for transferring coordinate position data detected based on the output signal of the indication pen to the output side, characterized in that the scanning means has an AND gate which is opened by the on signal of the switch and a negation signal of the command signal, and the scanning signal is supplied to the conductor groups only while the AND gate is open.