Display-integrated type tablet device
First Claim
Patent Images
1. A display-integrated type tablet device provided with:
- a display panel which has a plurality of first electrodes and a plurality of second electrodes, said first electrodes and said second electrodes being arranged in different directions, and which has pixels corresponding to places at which the first electrodes and the second electrodes intersect each other;
a control drive circuit, which can set a display period and a coordinate detection period by time sharing, and which, during the display period, successively applies voltage for image display to both the first and second electrodes and also periodically inverts the polarity of the voltage for image display, and which, during the coordinate detection period, successively applies voltage for coordinate detection to both the first and second electrodes;
a detection pen which can be capacity-coupled with both the first and second electrodes on the display panel to cause an electrostatically induced voltage to be developed; and
a coordinate detection circuit for receiving the electrostatically induced voltage developed to the detection pen by the voltage for coordinate detection during the coordinate detection period and detecting and outputting the coordinate specified by the detection pen based on the received electrostatically induced voltage,the display-integrated type tablet device further comprising;
a mode detection circuit for, during the display period, receiving the electrostatically induced voltage developed to the detection pen depending on polarity inversion of the voltage for image display and comparing the received electrostatically induced voltage with a previously set reference voltage, wherebyif the electrostatically induced voltage is greater than the reference voltage it decides as a detection mode in which the coordinate detection is to be effected, whileif the electrostatically induced voltage is smaller than the reference voltage it decides as a non-detection mode in which the coordinate detection is not to be effected,thus outputting a mode signal representing decision result; and
a coordinate output selection circuit for receiving a coordinate outputted by the coordinate detection circuit and a mode signal outputted by the mode detection circuit and then outputting the coordinate as it is if the mode signal represents the detection mode while halting the output of the coordinate if the mode signal represents the non-detection mode.
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Abstract
A display-integrated type tablet device provided with a liquid crystal display panel has a mode detection circuit. During the display period, the circuit receives electrostatically induced voltages developed on a detection pen and compares the received electrostatically induced voltage with a previously set reference voltage. If the electrostatically induced voltage is greater than the reference voltage, the mode detection circuit decides that a coordinate detection mode exists, while if the electrostatically induced voltage is smaller than the reference voltage a non-detection mode is determined.
75 Citations
27 Claims
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1. A display-integrated type tablet device provided with:
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a display panel which has a plurality of first electrodes and a plurality of second electrodes, said first electrodes and said second electrodes being arranged in different directions, and which has pixels corresponding to places at which the first electrodes and the second electrodes intersect each other; a control drive circuit, which can set a display period and a coordinate detection period by time sharing, and which, during the display period, successively applies voltage for image display to both the first and second electrodes and also periodically inverts the polarity of the voltage for image display, and which, during the coordinate detection period, successively applies voltage for coordinate detection to both the first and second electrodes; a detection pen which can be capacity-coupled with both the first and second electrodes on the display panel to cause an electrostatically induced voltage to be developed; and a coordinate detection circuit for receiving the electrostatically induced voltage developed to the detection pen by the voltage for coordinate detection during the coordinate detection period and detecting and outputting the coordinate specified by the detection pen based on the received electrostatically induced voltage, the display-integrated type tablet device further comprising; a mode detection circuit for, during the display period, receiving the electrostatically induced voltage developed to the detection pen depending on polarity inversion of the voltage for image display and comparing the received electrostatically induced voltage with a previously set reference voltage, whereby if the electrostatically induced voltage is greater than the reference voltage it decides as a detection mode in which the coordinate detection is to be effected, while if the electrostatically induced voltage is smaller than the reference voltage it decides as a non-detection mode in which the coordinate detection is not to be effected, thus outputting a mode signal representing decision result; and a coordinate output selection circuit for receiving a coordinate outputted by the coordinate detection circuit and a mode signal outputted by the mode detection circuit and then outputting the coordinate as it is if the mode signal represents the detection mode while halting the output of the coordinate if the mode signal represents the non-detection mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A display-integrated type tablet device having:
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a display panel which has a plurality of first electrodes and a plurality of second electrodes, said first electrodes and said second electrodes being arranged in different directions, and which has pixels corresponding to places at which the first electrodes and the second electrodes intersect each other; a detection pen having at its tip an electrode to be electrostatically coupled with the first electrodes and the second electrodes of the display panel; a first drive circuit for driving the first electrodes; a second drive circuit for driving the second electrodes; a display control circuit for controlling the first drive circuit and the second drive circuit during a display period to display an image onto the display panel; a detection control circuit for, during a coordinate detection period, controlling the first drive circuit to successively scan the first electrodes of the display panel while controlling the second drive circuit to successively scan the second 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 first 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 timing at which the second electrodes are scanned, the display-integrated type tablet device further comprising; inversion signal generation means for generating an inversion signal for setting in the display period a time point at which the direction of voltage applied to display members of the display panel is inverted; a first sampling means for selectively sampling an induced voltage developed to the electrode of the detection pen during a first specified interval in the display period including the time point at which the direction of voltage applied is inverted, the time point having been set depending on the inversion signal; a second sampling means for selectively sampling an induced voltage developed to the electrode of the detection pen during a second specified interval other than the first specified interval in the display period; a first processing means for converting the induced voltage sampled by the first sampling means into d.c. voltage and then comparing the value of the converted voltage with a reference voltage; a second processing means for converting the induced voltage sampled by the second sampling means into d.c. voltage and then comparing the value of the converted voltage with a reference voltage; and decision means for deciding whether or not the tip of the detection pen exists in proximity to the surface of the display panel, depending on comparison result by the first processing means and comparison result by the second processing means, and outputting a signal representing decision result. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A display-integrated type tablet device having:
- a liquid crystal panel, in which liquid crystals are 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 liquid crystal 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 liquid crystal panel;
a detection control circuit for, during a coordinate detection period, controlling the segment drive circuit to successively scan the segment electrodes of the liquid crystal panel while controlling the common drive circuit to successively scan the common electrodes;
an x-coordinate detection circuit for detecting an x-coordinate on the liquid crystal 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 a y-coordinate on the liquid crystal 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, the display-integrated type tablet device further comprising;inversion signal generation means for generating an inversion signal for setting in the display period a time point at which the direction of voltage applied to liquid crystals of the liquid crystal panel is inverted; a first sampling means for selectively sampling an induced voltage developed on the electrode of the detection pen during a first specified interval in the display period including the time point at which the direction of voltage, applied is inverted, the time point having been set depending on the inversion signal; a second sampling means for selectively sampling an induced voltage developed on the electrode of the detection pen during a second specified interval other than the first specified interval in the display period; a first processing means for amplifying the induced voltage sampled at a first amplification factor and then converting the result into d.c. voltage; a second processing means for amplifying the induced voltage sampled by the second sampling means at a second amplification factor greater than the first amplification factor and then converting the result into d.c. voltage; and decision means for comparing an output voltage from the first processing means and an output voltage from the second processing means together, deciding whether or not the tip of the detection pen exists in proximity to the surface of the liquid crystal panel, depending on the comparison result, and outputting a signal representing decision result. - View Dependent Claims (24, 25, 26, 27)
- a liquid crystal panel, in which liquid crystals are sandwiched between segment electrodes and common electrodes, orthogonally crossing each other, and which is driven by a duty-type drive method;
Specification