Display-integrated type tablet device
First Claim
1. A display-integrated type tablet device, comprising:
- a liquid crystal panel having a plurality of first electrodes arrayed in parallel to one another and a plurality of second electrodes arrayed in parallel to one another in a direction other than the direction in which the first electrodes are arrayed;
an electronic pen having at its tip an electrode coupled with the first electrodes and the second electrodes of the liquid crystal panel by floating capacity;
a display control circuit for producing a display control signal and display data for displaying an image to the plurality of first electrodes and the plurality of second electrodes of the liquid crystal panel;
a detection control circuit for producing a detection-scanning control signal for scanning the first electrodes and the second electrodes to detect coordinates of the tip of the electronic pen on the liquid crystal panel;
a switching circuit for switchedly selecting a side of the display control circuit for a display period to produce the display control signal and display data from the display control circuit and for switchedly selecting a side of the detection control circuit for a coordinate detection period to produce the detection-scanning control signal from the detection control circuit, under control of a control circuit;
a second-electrode drive circuit for generating a second-electrode drive signal during the display period to select in turn among the second electrodes according to the display control signal and for generating a second-electrode scan signal during the coordinate detection period to feed a scan voltage to the second electrodes in turn according to the detection-scanning control signal from the switching circuit;
a first-electrode drive circuit for generating a first-electrode drive signal during the display period to display pixels relative to the second electrodes selected by the second-electrode drive signal according to the display control signal and display data and for generating a first-electrode scan signal during the coordinate detection period to feed a scan voltage to the first electrodes in turn according to the detection-scanning control signal from the switching circuit; and
a coordinate detection circuit for receiving an input of induced voltage developed to the electrode of the electronic pen according to the second-electrode scan signal and the first-electrode scan signal fed from the second-electrode drive circuit and the first-electrode drive circuit to the second electrodes and the first electrodes, respectively, and then detecting coordinates of the tip of the electronic pen by a predetermined procedure on the basis of the induced voltage derived from the electronic pen to produce an x-coordinate signal and a y-coordinate signal, whereinthe control circuit sets the display period and the coordinate detection period, and controls the switching circuit in such a way that after the first-electrode drive signal and the second-electrode drive signal for effecting display have been applied to the last first electrode and the last second electrode in the display period, respectively, for a specified time period, the scanning of the first electrodes and the second electrodes for coordinate detection is not immediately started, but a specified idle time is allowed until the display period is succeeded by the coordinate detection period;
wherein the idle time is so set that when a voltage applied to the first electrodes and the second electrodes and set by a first signal for setting the state in which a voltage is applied to the first electrodes and the second electrodes during the display period is switched to a voltage applied to the first electrodes and the second electrodes and set by a second signal for setting the state in which a voltage is applied to the first electrodes and the second electrodes during the coordinate detection period, the idle time is approximately equal to a period over which an induced voltage developed to the tip electrode of the electronic pen reaches a reference level for the coordinate detection period.
1 Assignment
0 Petitions
Accused Products
Abstract
A switching circuit 7 switchedly selects the side of a detection control circuit 6 for the coordinate detection period in compliance with control of a control circuit 10. Then according to each signal from the detection control circuit 6, a segment drive circuit 3 generates a segment electrode scan signal to scan segment electrodes X of a liquid crystal panel 1 in turn. Subsequently, a common drive circuit 2 generates a common electrode scan signal to scan common electrodes Y in turn. An x-coordinate detection circuit 8 and a y-coordinate detection circuit 9 detects the x- and y-coordinates of the tip of an electronic pen 11 on the basis of an induced voltage developed to a tip electrode of the electronic pen 11. During the display period, the side of a display control circuit 4 is switchedly selected, displaying an image onto the liquid crystal panel 1. Thus, there is provided a display-integrated type tablet device into which display function has been integrated, in order to make the image easy-to-view and the device itself more compact, less costly.
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Citations
18 Claims
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1. A display-integrated type tablet device, comprising:
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a liquid crystal panel having a plurality of first electrodes arrayed in parallel to one another and a plurality of second electrodes arrayed in parallel to one another in a direction other than the direction in which the first electrodes are arrayed; an electronic pen having at its tip an electrode coupled with the first electrodes and the second electrodes of the liquid crystal panel by floating capacity; a display control circuit for producing a display control signal and display data for displaying an image to the plurality of first electrodes and the plurality of second electrodes of the liquid crystal panel; a detection control circuit for producing a detection-scanning control signal for scanning the first electrodes and the second electrodes to detect coordinates of the tip of the electronic pen on the liquid crystal panel; a switching circuit for switchedly selecting a side of the display control circuit for a display period to produce the display control signal and display data from the display control circuit and for switchedly selecting a side of the detection control circuit for a coordinate detection period to produce the detection-scanning control signal from the detection control circuit, under control of a control circuit; a second-electrode drive circuit for generating a second-electrode drive signal during the display period to select in turn among the second electrodes according to the display control signal and for generating a second-electrode scan signal during the coordinate detection period to feed a scan voltage to the second electrodes in turn according to the detection-scanning control signal from the switching circuit; a first-electrode drive circuit for generating a first-electrode drive signal during the display period to display pixels relative to the second electrodes selected by the second-electrode drive signal according to the display control signal and display data and for generating a first-electrode scan signal during the coordinate detection period to feed a scan voltage to the first electrodes in turn according to the detection-scanning control signal from the switching circuit; and a coordinate detection circuit for receiving an input of induced voltage developed to the electrode of the electronic pen according to the second-electrode scan signal and the first-electrode scan signal fed from the second-electrode drive circuit and the first-electrode drive circuit to the second electrodes and the first electrodes, respectively, and then detecting coordinates of the tip of the electronic pen by a predetermined procedure on the basis of the induced voltage derived from the electronic pen to produce an x-coordinate signal and a y-coordinate signal, wherein the control circuit sets the display period and the coordinate detection period, and controls the switching circuit in such a way that after the first-electrode drive signal and the second-electrode drive signal for effecting display have been applied to the last first electrode and the last second electrode in the display period, respectively, for a specified time period, the scanning of the first electrodes and the second electrodes for coordinate detection is not immediately started, but a specified idle time is allowed until the display period is succeeded by the coordinate detection period; wherein the idle time is so set that when a voltage applied to the first electrodes and the second electrodes and set by a first signal for setting the state in which a voltage is applied to the first electrodes and the second electrodes during the display period is switched to a voltage applied to the first electrodes and the second electrodes and set by a second signal for setting the state in which a voltage is applied to the first electrodes and the second electrodes during the coordinate detection period, the idle time is approximately equal to a period over which an induced voltage developed to the tip electrode of the electronic pen reaches a reference level for the coordinate detection period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A display-integrated type tablet device, comprising:
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a liquid crystal panel having a plurality of first electrodes arrayed in parallel to one another and a plurality of second electrodes arrayed in parallel to one another in a direction other than the direction in which the first electrodes are arrayed; an electronic pen having at its tip an electrode coupled with the first electrodes and the second electrodes of the liquid crystal panel by floating capacity; a display control circuit for producing a display control signal and display data for displaying an image to the plurality of first electrodes and the plurality of second electrodes of the liquid crystal panel; a detection control circuit for producing a detection-scanning control signal for scanning the first electrodes and the second electrodes to detect coordinates of the tip of the electronic pen on the liquid crystal panel; a switching circuit for switchedly selecting a side of the display control circuit for a display period to produce the display control signal and display data from the display control circuit and for switchedly selecting a side of the detection control circuit for a coordinate detection period to produce the detection-scanning control signal from the detection control circuit, under control of a control circuit; a second-electrode drive circuit for generating a second-electrode drive signal during the display period to select in turn among the second electrodes according to the display control signal and for generating a second-electrode scan signal during the coordinate detection period to feed a scan voltage to the second electrodes in turn according to the detection-scanning control signal from the switching circuit; a first-electrode drive circuit for generating a first-electrode drive signal during the display period to display pixels relative to the second electrodes selected by the second-electrode drive signal according to the display control signal and display data and for generating a first-electrode scan signal during the coordinate detection period to feed a scan voltage to the first electrodes in turn according to the detection-scanning control signal from the switching circuit; and a coordinate detection circuit for receiving an input of induced voltage developed to the electrode of the electronic pen according to the second-electrode scan signal and the first-electrode scan signal fed from the second-electrode drive circuit and the first-electrode drive circuit to the second electrodes and the first electrodes, respectively, and then detecting coordinates of the tip of the electronic pen by a predetermined procedure on the basis of the induced voltage derived from the electronic pen to produce an x-coordinate signal and a y-coordinate signal, wherein the coordinate detection circuit has an amplifier, and, when detecting a coordinate of the tip of the electronic pen on the basis of an induced voltage caused to the electrode of the electronic pen by a scan signal fed to one of the first electrodes and the second electrodes, whichever are greater in distance from the electronic pen and sited on the rear side of the liquid crystal panel on which the electronic pen is not present, the coordinate of the tip of the electronic pen is determined after the induced voltage has been amplified at a first amplification factor, and on the other hand, when detecting a coordinate of the tip of the electronic pen on the basis of an induced voltage caused to the electrode of the electronic pen by a scan signal fed to the other electrodes which are smaller in distance from the electronic pen and sited on the front side of the liquid crystal panel on which the electronic pen is present, the coordinate of the tip of the electronic pen is determined after the induced voltage has been amplified at a second amplification factor smaller than the first amplification factor.
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18. A display-integrated type tablet device, comprising:
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a liquid crystal panel having a plurality of first electrodes arrayed in parallel to one another and a plurality of second electrodes arrayed in parallel to one another in a direction other than the direction in which the first electrodes are arrayed; an electronic pen having at its tip an electrode coupled with the first electrodes and the second electrodes of the liquid crystal panel by floating capacity; a display control circuit for producing a display control signal and display data for displaying an image to the plurality of first electrodes and the plurality of second electrodes of the liquid crystal panel; a detection control circuit for producing a detection-scanning control signal for scanning the first electrodes and the second electrodes to detect coordinates of the tip of the electronic pen on the liquid crystal panel; a switching circuit for switchedly selecting a side of the display control circuit for a display period to produce the display control signal and display data from the display control circuit and for switchedly selecting a side of the detection control circuit for a coordinate detection period to produce the detection-scanning control signal from the detection control circuit, under control of a control circuit; a second-electrode drive circuit for generating a second-electrode drive signal during the display period to select in turn among the second electrodes according to the display control signal and for generating a second-electrode scan signal during the coordinate detection period to feed a scan voltage to the second electrodes in turn according to the detection-scanning control signal from the switching circuit; a first-electrode drive circuit for generating a first-electrode drive signal during the display period to display pixels relative to the second electrodes selected by the second-electrode drive signal according to the display control signal and display data and for generating a first-electrode scan signal during the coordinate detection period to feed a scan voltage to the first electrodes in turn according to the detection-scanning control signal from the switching circuit; and a coordinate detection circuit for receiving an input of induced voltage developed to the electrode of the electronic pen according to the second-electrode scan signal and the first-electrode scan signal fed from the second-electrode drive circuit and the first-electrode drive circuit to the second electrodes and the first electrodes, respectively, and then detecting coordinates of the tip of the electronic pen by a predetermined procedure on the basis of the induced voltage derived from the electronic pen to produce an x-coordinate signal and a y-coordinate signal, wherein the control circuit sets the display period and the coordinate detection period, and controls the switching circuit in such a way that after the first-electrode drive signal and the second-electrode drive signal for effecting display have been applied to the last first electrode and the last second electrode in the display period, respectively, for a specified time period, the scanning of the first electrodes and the second electrodes for coordinate detection is not immediately started, but a specified idle time is allowed until the display period is succeeded by the coordinate detection period; wherein the idle time is set longer than a period that continues after the display period is completed until the display state of the first-electrode drive circuit and the second-electrode drive circuit during the display period is cleared, with the mode switched to detection mode, and besides detection-scanning during the coordinate detection period is made ready for start.
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Specification