Display-integrated type tablet device

• US 5,392,058 A
• Filed: 05/13/1992
• Issued: 02/21/1995
• Est. Priority Date: 05/15/1991
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Tagawa, Takao
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): STOLL, KARA FARNANDEZ
• Application Number:
  US07/883,608
• Time in Patent Office: 1,014 Days
• Field of Search: 340/712, 340/784, 340/706, 340/718, 340/719, 340/783, 178/18, 178/19, 341/32, 345/173, 345/174, 345/175, 345/177, 345/179, 345/103, 345/104, 345/100
• US Class Current: 345/104
• CPC Class Codes: B25J 19/0012 using fluidic devices
• CPC Class Codes: B66C 23/005 with balanced jib, e.g. pantograph arrangement, the jib being moved manually
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/0441 using active external devices, e.g. active pens, for receiving changes in electrical potential transmitted by the digitiser, e.g. tablet driving signals
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A multiplexer 13 selects the input terminal B side for a display period while it selects the input terminal A side for a coordinate detection period. A lower common drive circuit 2L, based on shift data transmitted from the multiplexer 13, operates in parallel with an upper common drive circuit 2U during the display period while it operates in series with the upper common drive circuit 2U during the coordinate detection period. An upper segment drive circuit 3U and a lower segment drive circuit 3L simultaneously operate to drive upper segment electrodes XU and lower segment electrodes XL simultaneously in the same direction. Thus, during the display period there is displayed an image simultaneously onto the upper half 1wU and the lower half 1wL of a display panel 1w, thereby improving the duty ratio of display. During the coordinate detection period, on the other hand, the upper half 1wU and the lower half 1wL of the display panel 1w are serially scanned during the coordinate detection period, whereby y-coordinates of two points P.sub. 1 and P₂ are detected correctly.

Claims

1. A display-integrated type tablet device having:

a display panel, in which display-use material is sandwiched between segment electrodes and common electrodes, orthogonally crossing each other, and which is driven by a duty-type drive method;

a detection pen having at its tip an electrode to be electrostatically coupled with the segment electrodes and the common electrodes of the display panel;

a segment drive circuit for driving the segment electrodes;

a common drive circuit for driving the common electrodes;

a display control circuit for controlling the segment drive circuit and the common drive circuit during a display period to display an image onto the display panel;

a detection control circuit for controlling the segment drive circuit during a coordinate detection period to successively scan the segment electrodes of the display panel while controlling the common drive circuit to successively scan the common electrodes;

an x-coordinate detection circuit for detecting the x-coordinate on the display panel specified by the tip of the detection pen from both the timing at which an output signal from the detection pen is generated and the timing at which the segment electrodes are scanned; and

a y-coordinate detection circuit for detecting the y-coordinate on the display panel specified by the tip of the detection pen from both the timing at which an output signal from the detection pen is generated and the timing at which the common electrodes are scanned, wherein

the segment electrodes are divided into two, one side segment electrodes belonging to one half region on one side of the display panel and the other side segment electrodes belonging to the other half region on the other side opposite to the aforementioned one side;

the common electrodes are divided into two, one side common electrodes belonging to one half region on the one side of the display panel and the other side common electrodes belonging to the other half region on the aforementioned other side;

the segment drive circuit is composed of a one side segment drive circuit for driving the one side segment electrodes and the other side segment drive circuit for driving the other side segment electrodes;

the common drive circuit is composed of a one side common drive circuit for driving the one side common electrodes and the other side common drive circuit for driving the other side common electrodes;

the one side segment drive circuit and the other side segment drive circuit, or the one side common drive circuit and the other side common drive circuit have a shift register and

a shift data feed path switching circuit for switching a shift data feed path so that shift data are inputted, in parallel mode, simultaneously into the two shift registers of the one side drive circuit and the other side drive circuit, both having the aforementioned shift registers, while shift data are inputted in serial mode, first only into the shift register of the one side drive circuit, thereafter the shift data outputted from the shift register of the one side drive circuit is inputted into the shift register of the other side drive circuit;

whereby

the one side drive circuit and the other side drive circuit are driven in parallel in the parallel mode while the one side drive circuit and the other side drive circuit are driven in series in the serial mode, by switching of the shift data feed path effected by the shift data feed path switching circuit.

2. A display-integrated type tablet device as claimed in claim 1, wherein

the shift data feed path switching circuit is so arranged that it switches the shift data feed path to the parallel mode side for the display period while it switches the path to the serial mode side for the coordinate detection period, whereby

the one side drive circuit and the other side drive circuit are driven in parallel during the display period to display an image simultaneously onto the one side half region and the other side half region of the display panel while the one side drive circuit and the other side drive circuit are driven in series during the coordinate detection period to scan the one side half region of the display panel and successively scan the other half region of the display panel.

3. A display-integrated type tablet device as claimed in claim 1, wherein the one side drive circuit having a shift register is the one side common drive circuit while the other side drive circuit having a shift register is the other side common drive circuit;

the shift data feed path switching circuit is a multiplexer;

a shift data output terminal of the shift register of the one side common drive circuit is connected to one input terminal of the multiplexer and a shift data input terminal of the shift register of the one side common drive circuit is connected to the other input terminal of the multiplexer while a shift data input terminal of the shift register of the other side common drive circuit is connected to an output terminal of the multiplexer.

4. A display-integrated type tablet device as claimed in claim 1, wherein

the drive circuit composed of the one side drive circuit and the other side drive circuit respectively having shift registers is the common drive circuit, the common drive circuit having an odd number of shift registers connected in series;

the shift data feed path switching circuit is a shift register located at the center of the odd number of shift registers that the common drive circuit has;

the shift register located at the center having a first input terminal, through which shift data is inputted to the head of the shift register, and a second input terminal, through which shift data is interruptively inputted to the center of the shift register, and so arranged as to control allowance or disallowance of interruptive input from the second input terminal depending on an external control signal, whereby

during the parallel mode, interruptive input from the second input terminal of the shift register located at the center is allowed by the control signal to input shift data simultaneously into the head of the shift register at one end of the shift register row that the common drive circuit has and into the second input terminal of the shift register located at the center, so that the one side common drive circuit having the one side half of the shift register row and the other side common drive circuit having the other side half of the shift register row are driven in parallel, while

during the serial mode, interruptive input from the second input terminal of the shift register is inhibited by the control signal to input shift data only into the head of the shift register at the one end of the shift register row, so that the one side common drive circuit and the other side common drive circuit are driven in series.

5. A display-integrated type tablet device as claimed in claim 1, wherein

the pulse width of the shift data in the coordinate detection period is made wider than the cycle of transfer clocks for the shift register.

6. A display-integrated type tablet device as claimed in claim 1, wherein

at least one drive circuit of the segment drive circuit and the common drive circuit is arranged so as to effect electrode scanning a plurality of times during the one-time coordinate detection period.

7. A display-integrated type tablet device as claimed in claim 6, wherein

either of the segment electrodes or the common electrodes, whichever farther from the detection pen, are scanned a plurality of times.

8. A display-integrated type tablet device having:

a display panel, in which display-use material is sandwiched between segment electrodes and common electrodes, orthogonally crossing each other, and which is driven by a duty-type drive method;

a detection pen having at its tip an electrode to be electrostatically coupled with the segment electrodes and the common electrodes of the display panel;

a segment drive circuit for driving the segment electrodes;

a common drive circuit for driving the common electrodes;

a display control circuit for controlling the segment drive circuit and the common drive circuit during a display period to display an image onto the display panel;

a detection control circuit for controlling the segment drive circuit during a coordinate detection period to successively scan the segment electrodes of the display panel while controlling the common drive circuit to successively scan the common electrodes;

an x-coordinate detection circuit for detecting the x-coordinate on the display panel specified by the tip of the detection pen from both the timing at which an output signal from the detection pen is generated and the timing at which the segment electrodes are scanned; and

a y-coordinate detection circuit for detecting the y-coordinate on the display panel specified by the tip of the detection pen from both the time at which an output signal from the detection pen is generated and the timing at which the common electrodes are scanned, wherein

the segment electrodes are divided into two, one side segment electrodes belonging to one half region on one side of the display panel and the other side segment electrodes belonging to the other half region on the other side opposite to the aforementioned one side;

the common electrodes are divided into two, one side common electrodes belonging to one half region on one side of the display panel and the other side common electrodes belonging to the other side half region opposite to the aforementioned one side;

one of the segment drive circuit and the common drive circuit is composed of a one side drive circuit for driving the one side electrodes and the other side drive circuit for driving the other side electrodes;

the drive circuit, other than the one composed of a one side drive circuit and the other side drive circuit, having the one side electrodes and the other side electrodes connected thereto in parallel and in conjunction with each other;

the one side drive circuit and the other side drive circuit are so arranged that they generate a scan signal having a scan pulse of a voltage that does not contribute to display of the display panel depending on an external control signal during a coordinate detection period and they deliver the scan signal to all the electrodes to be driven at the same timing;

the x-coordinate detection circuit is so arranged that it detects the region on the display panel in which the tip of the detection pen exists, from both the timing at which a scan signal having a scan pulse of a voltage that does not contribute to the display from the one side drive circuit and the other side drive circuit from the detection pen is generated and further from the peak value of the output signal while the y-coordinate detection circuit is so arranged that it detects the region on the display panel in which the tip of the detection pen exists, from both the timing at which a scan signal having a scan pulse of a voltage that does not contribute to the display from the one side drive circuit and the other side drive circuit is inputted and the timing at which an output signal from the detection pen is generated and further from the peak value of the output signal, whereby

it is detected whether the tip of the detection pen exists in the one side half region of the display panel or in the other side half region thereof.

9. A display-integrated type tablet device as claimed in claim 8, wherein

the coordinate detection period is divided into a region detection period for detecting a region on the display panel in which the tip of the detection pen exists, an x-coordinate detection period for detecting the x-coordinate on the display panel specified by the detection pen, and a y-coordinate detection period for detecting the y-coordinate specified by the detection pen, and wherein

during the region detection period, from the one side drive circuit and the other side drive circuit, scan signals having scan pulses of voltage which does not contribute to the display and which differ in phase between the drive circuits are outputted to scan the one side half region and the other side half region of the display panel at different timings in series, and

during the x-coordinate detection period, the segment drive circuits are simultaneously controlled by the detection control circuit to scan the one side half region and the other side half region of the display panel in parallel, while during the y-coordinate detection period, the common drive circuits are simultaneously controlled by the detection control circuit to scan the one side half region and the other side half region of the display panel in parallel,

the x-coordinate detection circuit being arranged so that, during the region detection period, it detects the region on the display panel in which the tip of the detection pen exits depending on an output signal from the detection pen and, during the x-coordinate detection period, it determines the x-coordinate on the display panel specified by the tip of the detection pen depending on detection result in the region detection period,

the y-coordinate detection circuit being arranged so that, during the region detection period, it detects the region on the display panel in which the tip of the detection pen exists and, during the y-coordinate detection period, it determines the y-coordinate on the display panel specified by the tip of the detection pen depending on detection result in the region detection period.

10. A display-integrated type tablet device as claimed in claim 8, wherein

both of the segment drive circuit and the common drive circuit are composed of the one side drive circuit and the other side drive circuit and also the external control signal is inputted into all the drive circuits, and

during the coordinate detection period, for each of the drive circuits to generate a scan signal having a scan pulse of a voltage that does not contribute to the display and input it all the electrodes to be driven depending on an external control signal, the one side segment drive circuit and the one side common drive circuit generate scan signals having a scan pulse of the same voltage and input them at the same timing into the electrodes to be driven while the other side segment drive circuit and the other side common drive circuit generate scan signals differing in phase from the scan signals from the two one side drive circuits having the scan pulse of the same voltage to input them at the same timing into all the electrodes to be driven, and

the x-coordinate detection circuit or the y-coordinate detection circuit detects the region on the display panel in which the tip of the detection pen exists from both the timing at which the scan signal having the scan pulses of voltages that do not contribute to the display from the two one side drive circuits and the two other side drive circuits are inputted and the timing at which an output signal from the detection pen is generated and further from the peak value of the output signal.

11. A display-integrated type tablet, comprising:

a duty-type display panel, in which a display material is disposed between segment electrodes and common electrodes, the segment electrodes being divided into first segment electrodes and second segment electrodes at approximately center of a display screen;

a first segment drive circuit for driving the first segment electrodes, one side terminals of said first segment electrodes being electrically connected to the first segment drive circuit, while the other side terminals of said first segment electrodes being opened;

a second segment drive circuit for driving the second segment electrodes, one side terminals of said second segment electrodes being electrically connected to the second segment drive circuit, while the other side terminals of said second segment electrodes being opened;

a common drive circuit for driving the common electrodes, one side terminals of said common electrodes being electrically connected to the common drive circuit, while the other side terminals of said common electrodes being opened;

a display control circuit for, during a display period, controlling the first segment drive circuit, the second segment drive circuit and the common drive circuit to cause the display panel to simultaneously effect the display of the upper half and the display of the lower half of the display panel;

a position detection control circuit for, during a position detection period, controlling the first segment drive circuit to successively apply first segment scan signals to the one side terminals of the first segment electrodes for x-coordinate detection, for controlling the second segment drive circuit to successively apply second segment scan signals to the one side terminals of the second segment electrodes for x-coordinate detection, and for controlling the common drive circuit to successively apply common scan signals to the one side terminals of the common electrodes for y-coordinate detection;

a position detection pen to be electrostatically coupled with the first segment electrodes, the second segment electrodes, and the common electrodes; and

a coordinate detection circuit for detecting coordinates of a position on the display panel specified by the position detection pen depending on an output signal of the position detection pen.

12. A display-integrated type tablet as claimed in claim 11, wherein the position detection control circuit is so arranged as to control the first segment drive circuit and the second segment drive circuit to scan the first segment electrodes and the second segment electrodes simultaneously in parallel.

13. A display-integrated type tablet as claimed in claim 11, wherein the position detection control circuit is so arranged as to scan the upper segment electrodes during one period and scan the lower segment electrodes during another period, and to scan the upper half of the common electrodes in the display panel and the lower half of the common electrodes of the display panel simultaneously in parallel, and the coordinate detection circuit is so arranged as to decide whether the position detection pen exists in the upper half or in the lower half of the display panel, from both an output signal and scan timing of the position detection pen in the scanning of the upper segment electrodes and both an output signal and scan timing of the position detection pen in the scanning of the lower segment electrodes, and to detect the y-coordinate of the position of the position detection pen from both the upper or lower decision result and an output signal and scan timing of the position detection pen in the scanning of the common electrodes.

14. A display-integrated type tablet as claimed in claim 11, wherein the position detection control circuit is so arranged as to scan the upper segment electrodes and the lower segment electrodes simultaneously in parallel with an upper segment drive signal and a lower segment drive signal, which differ in phase from each other, respectively, and to scan the upper half of the common electrodes of the display panel and lower half of the common electrodes of the display panel simultaneously in parallel, and the coordinate detection circuit is so arranged as to decide whether the position detection pen exists in the upper half or in the lower half of the display panel from phase difference between the output signal of the position detection pen in the scanning of the upper segment electrodes and the lower segment electrodes and the upper segment drive signal or the lower segment drive signal and to detect the y-coordinate of the position of the position detection pen from both the upper or lower detection result and the output signal and scan timing of the position detection pen in the scanning of the common electrodes.

15. A display-integrated type tablet as claimed in claim 14, wherein the upper segment drive signal and the lower segment drive signal are high-frequency pulse signals of the same frequency which differ in phase from each other.

16. A display-integrated type tablet as claimed in claim 14, wherein the upper segment drive signal and the lower segment drive signal are high-frequency sine-wave signals of the same frequency which differ in phase from each other.

17. A display-integrated type tablet as claimed in claim 14, wherein the upper segment drive signal and the lower segment drive signal are single pulse signals which differ in phase from each other.

18. A display-integrated type tablet as claimed in claim 11, wherein the first segment electrodes and the second segment electrodes are opposed to each other so that they can lie on respective parallel straight lines.

19. A display-integrated type tablet having:

a display panel having first electrodes and second electrodes;

a first drive circuit for applying voltage to the first electrodes;

a second drive circuit for applying voltage to the second electrodes;

a detection pen to be electrostatically coupled with the first electrodes and the second electrodes; and

means for amplifying an electrostatically induced voltage of the detection pen, wherein carried out by time sharing are display of an image with the display panel and coordinate detection for determining a position of the detection pen according to the electrostatically induced voltage, characterized in that

the first drive circuit is provided with a plurality of driving integrated circuits connected in cascade by serial input/output terminals, the driving integrated circuits comprising;

scan mode setting means for setting scan mode of the driving integrated circuits to a first mode for a display period and to a second mode for a coordinate detection period;

the serial input/output terminal;

a data input terminal for receiving display data during the display period;

a shift data input/output terminal for receiving shift data during the coordinate detection period;

a memory for memorizing data inputted from the data input terminal;

a shift register for shifting the shift data inputted from the shift data input/output terminal;

a driver for generating scan signals based on the shift data and the display data and outputting the scan signals to the first electrodes; and

control means, wherein the control means cause the memory to memorize, in the first mode, the display data inputted from the data input terminal and thereafter to output the display data to the driver simultaneously in parallel, while the control means cause the shift register to shift and output, in the second mode, shift data inputted through the shift data input/output terminal to the driver so that the scan signal on the shift data can be successively serially inputted from the driver to the first electrodes.

20. A display-integrated type tablet as claimed in claim 19, wherein the pulse width of the shift data is greater than the cycle of a clock signal which transfers the shift data.

21. A display-integrated type tablet as claimed in claim 19, further comprising shift data control means for, when carrying out the scanning of the first drive circuit and the scanning of the second drive circuit by time sharing during the coordinate detection period, making shift data outputted from the final stage of a drive circuit to be scanned first and then inputted into the first stage of a drive circuit to be scanned second.

22. A display-integrated type tablet as claimed in claim 21, wherein the shift data control means serves to delay the shift data outputted from the final stage of the drive circuit to be scanned first and thereafter to input the same into the first stage of the drive circuit to be scanned second.

23. A display-integrated type tablet as claimed in claim 19, wherein the second drive circuit is an integrated circuit having the same construction as that of the driving integrated circuit forming the first drive circuit, and the scan mode setting means is provided by a plurality of integrated circuits, which are connected in cascade and which serve to set the scan mode normally to the second mode.

24. A display-integrated type tablet as claimed in claim 19, further comprising a multiplexer, wherein one of input terminals of the multiplexer receives a control signal for chip-selecting the driving integrated circuit of a first stage of the first drive circuit, the other of the input terminals of the multiplexer receives the shift data, and an output terminal of the multiplexer is connected to the serial input/output terminal of the driving integrated circuit of the first stage so that the control signal and the shift data can be switchedly inputted in the serial input/output terminal of the driving integrated circuit in the first mode and the second mode respectively.

25. A display-integrated type tables device having:

a display panel, in which display-use material is sandwiched between segment electrodes and common electrodes, orthogonally crossing each other, and which is driven by a duty-type drive method;

a detection pen having at its tip an electrode to be electrostatically coupled with the segment electrodes and the common electrodes of the display panel;

a segment drive circuit for driving the segment electrodes;

a common drive circuit for driving the common electrodes;

a display control circuit for controlling the segment drive circuit and the common drive circuit during a display period to display an image onto the display panel;

a detection control circuit for controlling the segment drive circuit during a coordinate detection period to successively scan the segment electrodes of the display panel while controlling the common drive circuit to successively scan the common electrodes;

an x-coordinate detection circuit for detecting the x-coordinate on the display panel specified by the tip of the detection pen from both the timing at which an output signal from the detection pen is generated and the timing at which the segment electrodes are scanned; and

a y-coordinate detection circuit for detecting the y-coordinate on the display panel specified by the tip of the detection pen from both the timing at which an output signal from the detection pen is generated and the timing at which the common electrodes are scanned, wherein the segment electrodes are divided into two, one side segment electrodes belonging to one half region on one side of the display panel and the other side segment electrodes belonging to the other half region on the other side opposite to the aforementioned one side;

the common electrodes are divided into two, one side common electrodes belonging to one half region on the one side of the display panel and the other side common electrodes belonging to the other half region on the aforementioned other side;

the segment drive circuit is composed of a one side segment drive circuit for driving the one side segment electrodes and the other side segment drive circuit for driving the other side segment electrodes;

the common drive circuit is composed of a one side common drive circuit for driving the one side common electrodes and the other side common drive circuit for driving the other side common electrodes;

the one side common drive circuit and the other side common drive circuit have a shift register and

a shift data feed path switching circuit for switching a shift data feed path so that shift data are inputted, in parallel mode, simultaneously into the two shift registers of the one side common drive circuit and the other side common drive circuit, both having the aforementioned shift registers;

while shift data are inputted in serial mode, first only into the shift register of the one side common drive circuit, thereafter the shift data are outputted from the shift register of a final stage of the one side common drive circuit, and simultaneously or thereafter the shift data are inputted into the shift register of the other side common drive circuit;

whereby;

the one side common drive circuit and the other side common drive circuit are driven in parallel in the parallel mode;

the one side common drive circuit an the other side common drive circuit are driven in series in the serial mode, by switching of the shift data feed path effected by the shift data feed path switching circuit.

26. A display-integrated type table device as claimed in claim 25, wherein

the shift data feed path switching circuit is so arranged that it switches the shift data feed path to the parallel mode side for the display period, while it switches the path to the serial mode side for the coordinate detection period, whereby

the one side common drive circuit and the other side common drive circuit are driven in parallel during the display period to display an image simultaneously onto the side half region and the other side half region of the display panel, while the one side common drive circuit and the other side common drive circuit are driven in series during the coordinate detection period to scan the one side half region of the display panel and successively scan the other half region of the display panel.

27. A display-integrated type tablet device as claimed in claim 26, wherein the shift data feed path switching circuit is a multiplexer;

a shift data output terminal of the shift register of the one side common drive circuit is connected to one input terminal of the multiplexer and a shift data input terminal of the shift register of the one side common drive circuit is connected to the other input terminal of the multiplexer, while a shift data input terminal of the shift register of the other side common drive circuit is connected to an output terminal of the multiplexer.

28. A display-integrated type tabled device as claimed in claim 25, wherein the shift data feed path switching circuit is a multiplexer;

a shift data output terminal of the shift register of the one side common drive circuit is connected to one input terminal of the multiplexer and a shift data input terminal of the shift register of the one side common drive circuit is connected to the other input terminal of the multiplexer, while a shift data input terminal of the shift register of the other side common drive circuit is connected to an output terminal of the multiplexer.

29. A display-integrated type tablet device as claimed in claim 25, wherein

the pulse width of the shift data in the coordinate detection period is made wider than the cycle of transfer clocks for the shift register.

30. A display-integrated type tablet device having:

a display panel, in which display-use material is sandwiched between segment electrodes and common electrodes, orthogonally crossing each other, and which is driven by a duty-type drive method;

a detection pen having at is tip an electrode to be electrostatically coupled with the segment electrodes and the common electrodes of the display panel;

a segment drive circuit for driving the segment electrodes;

a common drive circuit for driving the common electrodes;

a display control circuit for controlling the segment drive circuit and the common drive circuit during a display period to display an image onto the display;

a detection control circuit of controlling the segment drive circuit during a coordinate detection period to successively scan the segment electrodes of the display panel, while controlling the common drive circuit to successively scan the common electrodes;

an x-coordinate detection circuit for detecting the x-coordinate on the display panel specified by the tip of the detection pen from both the timing at which an output signal from the detection pen is generated and the timing at which the segment electrodes are scanned; and

a y-coordinate detection circuit for detecting the y-coordinate on the display panel specified by the tip of the detection pen from both the timing at which an output signal from the detection pen is generated and the timing at which the common electrodes are scanned, wherein

the segment electrodes are divided into two, one side segment electrodes belonging to one half region on one side of the display panel and the other side segment electrodes belonging to the other half region on the other side opposite to the aforementioned one side, said one side segment electrodes being opposed to the other side segment electrodes in such a manner that the one side segment electrodes and the other side segment electrodes lie on parallel straight lines;

the segment drive circuit is composed of a one side segment drive circuit for driving the one side segment electrodes and the other side segment drive circuit for driving the other side segment electrodes, wherein the one side segment drive circuit and the other side segment drive circuit have the same structure, shape and dimension, and are opposed to each other, and yet have respectively a directional shift register provided with a control terminal for setting a shifting direction,

whereby the one side segment electrodes and the other side segment electrodes are serially scanned in the same direction during the coordinate detection period by controlling the control terminals of the one side segment drive circuit and the other side segment drive circuit.