EP0504728A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Display-integrated type tablet device
Assignee: Sharp Corp
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Filing: 1992-03-11
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Granted: —
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Expires: 2012-03-11
Abstract
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.
Inventors
- 👤 Takao Tagawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 09:03
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/0412; G06F3/0416; G06F3/0418; G06F3/04184; G06F3/044; G06F3/0441; G06F3/0446
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
535 words
A display-integrated type tablet device, comprising: a liquid crystal panel (1) having a plurality of segment electrodes X arranged in parallel and a plurality of common electrodes Y arranged in parallel and being driven by a duty-type drive method; an electronic pen (11) having at its tip an electrode of certain high input impedance coupled with the segment electrodes X and the common electrodes Y of the liquid crystal panel (1) by floating capacity; a display control circuit (4) for producing a display control signal and display data for displaying an image onto a pixel matrix constructed by crossing regions between the plurality of segment electrodes X and the plurality of common electrodes Y of the liquid crystal panel (1); a detection control circuit (6) for producing a scan control signal for scanning the segment electrodes X and the common electrodes Y of the liquid crystal panel (1); a switching circuit (7) for switchedly selecting a side of the display control circuit (4) for a display period to produce the display control signal and display data from the display control circuit (4) while switchedly selecting a side of the detection control circuit (6) for a coordinate detection period to produce the scan control signal from the detection control circuit (6); a common drive circuit (2) for generating a common electrode drive signal during the display period to select in turn among the common electrodes Y according to the display control signal from the switching circuit (7) while generating a common electrode scan signal during the coordinate detection period to scan the common electrodes Y in turn without displaying the image onto the pixel matrix according to the scan control signal from the switching circuit (7); a segment drive circuit (3) for generating a segment electrode drive signal during the display period to display pixels relative to the common electrodes Y selected by the common electrode drive signal according to the display control signal and display data from the switching circuit (7) while generating a segment electrode scan signal during the coordinate detection period to scan the segment electrodes X in turn without displaying the image onto the pixel matrix according to the scan control signal from the switching circuit (7); and a coordinate detection circuit (8, 9) for receiving an input of induced voltage developed to the electrode of the electronic pen (11) according to each scan signal fed from the common drive circuit (2) and the segment drive circuit (3) to the common electrodes Y and the segment electrodes X and for, during the coordinate detection period, detecting the coordinate of the tip of the electronic pen (11) by a predetermined procedure on the basis of the induced voltage derived from the electronic pen (11) to produce an x-coordinate signal and a y-coordinate signal, wherein the display period and the coordinate detection period is appropriately set by the control circuit (10), so that during the set display period the image is displayed onto the pixel matrix of the liquid crystal panel (1) while during the coordinate detection period a point of the tip of the electronic pen (11) on the liquid crystal panel (1) is detected without displaying the image onto the pixel matrix.
Claim 2
Dependent Claim
63 words
A display-integrated type tablet device as claimed in claim 1, wherein the common drive circuit (2) and the segment drive circuit (3) generate the common electrode scan signal and the segment electrode scan signal during the coordinate detection period such that a voltage applied to the liquid crystal of the pixels is lower than a threshold value of the liquid crystal display voltage.
Claim 3
Dependent Claim
56 words
A display-integrated type tablet device as claimed in claim 1, wherein at least one drive circuit of the common drive circuit (2) and the segment drive circuit (3) generates such a scan signal during the coordinate detection period that scan pulses are simultaneously fed to a specified number of electrodes in the liquid crystal panel (1).
Claim 4
Dependent Claim
69 words
A display-integrated type tablet device as claimed in claim 1, wherein either one drive circuit of the common drive circuit (2) or the segment drive circuit (3), whichever feeds a scan signal to one group of electrodes farther from the electronic pen (11), generates a scan signal having a peak value higher than that of a scan signal generated by the other drive circuit during the coordinate detection period.
Claim 5
Dependent Claim
83 words
A display-integrated type tablet device as claimed in claim 3, wherein either one drive circuit of the common drive circuit (2) or the segment drive circuit (3), whichever feeds a scan signal to one group of electrodes farther from the electronic pen (11), generates such a scan signal during the coordinate detection period that scan pulses are simultaneously fed to a specified number of electrodes more than the number of electrodes to which scan pulses are simultaneously fed by the other drive circuit.
Claim 6
Dependent Claim
172 words
A display-integrated type tablet device as claimed in claim 1, wherein the coordinate detection circuit (8, 9) has an amplifier, and wherein for detecting the coordinate of the tip of the electronic pen (11) on the basis of an induced voltage caused to the electrode of the electronic pen (11) by a scan signal fed to one of the two electrode groups, the common electrodes Y and the segment electrodes X, whichever farther from the electronic pen (11), the coordinate of the tip of the electronic pen (11) is determined after the induced voltage has been amplified at a first amplification factor while for detecting the coordinate of the tip of the electronic pen (11) on the basis of an induced voltage caused to the electrode of the electronic pen (11) by a scan signal fed to the other group of electrodes, the coordinate of the tip of the electronic pen (11) is determined after the induced voltage has been amplified at a second amplification factor smaller than the first amplification factor.
Claim 7
Dependent Claim
230 words
A display-integrated, type tablet device as claimed in claim 1, further comprising: a display a.c. conversion signal generating section for generating a display a.c. conversion signal for setting a time point at which the voltage applied to the liquid crystal of each pixel in the pixel matrix is inverted during the display period; and a detection a.c. conversion signal generating section for setting a time point at which a voltage is applied to the liquid crystal of each pixel during the coordinate detection period and further generating a detection a.c. conversion signal for inverting the direction in which the voltage is applied at a time point other than during the common electrode scan period and the segment electrode scan period, wherein during the display period the common drive circuit (2) and the segment drive circuit (3) generate such a common electrode drive signal and a segment electrode drive signal, respectively, that the direction in which a voltage is applied to the liquid crystal of each pixel is inverted according to the display a.c. conversion signal while during the coordinate detection period the common drive circuit (2) and the segment drive circuit (3) generate such a common electrode scan signal and a segment electrode scan signal that the direction in which a voltage is applied to the liquid crystal of each pixel is inverted according to the display a.c. conversion signal.
Claim 8
Dependent Claim
173 words
A display-integrated type tablet device as claimed in claim 1, further comprising: a display a.c. conversion signal generating section for generating a display a.c. conversion signal for setting a time point at which the voltage applied to the liquid crystal of each pixel in the pixel matrix is inverted during the display period, wherein during the display period the common drive circuit (2) and the segment drive circuit (3) generate such a common electrode drive signal and a segment electrode drive signal, respectively, that the direction in which a voltage is applied to the liquid crystal of each pixel is inverted according to the display a.c. conversion signal while during the coordinate detection period the common drive circuit and the segment drive circuit generate such a common electrode scan signal and a segment electrode scan signal, respectively, that the average value of voltage applied to the liquid crystal of each pixel is made zero without inverting the relation whether the scan voltage level is higher or lower than the relevant reference voltage level.
Claim 9
Dependent Claim
46 words
A display-integrated type tablet device as claimed in claim 8, wherein the common drive circuit (2) and the segment drive circuit (3) generates the common electrode scan signal and the segment electrode scan signal, respectively, equal in their reference voltage value during the coordinate detection period.
Claim 10
Dependent Claim
48 words
A display-integrated type tablet device as claimed in claim 9, wherein the common drive circuit 2 and the segment drive circuit (3) generate the common electrode scan signal and the segment electrode scan signal, respectively, equal in peak values of their scan pulses during the coordinate detection period.
Claim 11
Dependent Claim
111 words
A display-integrated type tablet device as claimed in claim 8, wherein at least one drive circuit of the common drive circuit 2 and the segment drive circuit (3) generates such a common electrode drive signal or a segment electrode drive signal that the average value of voltage applied to the liquid crystal of each pixel is made zero without inverting the relation whether the scan voltage level is higher or lower than the relevant reference voltage level by setting an interval, which does not contribute to coordinate detection, into a waveform of the scan signal and inserting a signal having a specified waveform into the interval during the coordinate detection period.
Claim 12
Dependent Claim
140 words
A display-integrated type tablet device as claimed in claim 8, wherein either one drive circuit of the common drive circuit (2) or the segment drive circuit 3 generates such a common electrode drive signal or a segment electrode drive signal during the coordinate detection period that the average value of voltage applied to the liquid crystal of each pixel is made zero without inverting the relation whether the scan voltage level is higher or lower than the relevant reference voltage level, by making either one value of pulse width or peak value of a scan pulse inserted into the scan signal different from the either one value of pulse width or peak value of a scan pulse inserted into a scan signal generated by the other drive circuit of the common drive circuit (2) or the segment drive circuit (3).
Claim 13
Dependent Claim
126 words
A display-integrated type tablet device as claimed in claim 12, wherein either one drive circuit of the common drive circuit (2) or the segment drive circuit (3), whichever applies a scan signal to one group of the electrodes farther from the electronic pen 11, generates a scan signal into which a scan pulse having a peak value higher than that of a scan pulse inserted into a scan signal generated by the other drive circuit is inserted during the coordinate detection period, and wherein during the coordinate detection period the other drive circuit generates a scan signal into which a scan pulse having a pulse width greater than that of a scan pulse inserted into the scan signal generated by the one drive circuit is inserted.
Claim 14
Dependent Claim
138 words
A display-integrated type tablet device as claimed in claim 1, wherein at least one drive circuit of the common drive circuit (2) and the segment drive circuit (3) generates during the coordinate detection period a scan signal in which a high-frequency wave has been inserted into the scan period in the scan signal, and wherein the coordinate detection circuit (8, 9), having a filter (22, 23) for separating a high-frequency component of an induced voltage derived from the electronic pen (11), separates the high-frequency component of an induced voltage developed to the electrode of the electronic pen according to the scan signal, generated by the one drive circuit, into which the high-frequency wave has been inserted and thereby detects coordinates of the tip of the electronic pen (11) by a predetermined procedure according to the separated high-frequency component.
Claim 15
Dependent Claim
197 words
A display-integrated, type tablet device as claimed in claim 14, wherein the common drive circuit (2) generates during the coordinate detection period a common electrode scan signal in which a first high-frequency wave having a specified frequency has been inserted into the scan period, the segment drive circuit (3) generates during the coordinate detection period a segment electrode scan signal in which a second high-frequency wave having a specified frequency different from the first high-frequency wave has been inserted into the scan period, and wherein the coordinate detection circuit (8, 9) has both a first filter (23) for separating the first high-frequency component of an induced voltage developed to the electrode of the electronic pen according to the common electrode scan signal and the segment electrode scan signal and a second filter (22) for separating the second high-frequency component thereof, and detects the y-coordinate of the tip of the electronic pen (11) by a predetermined procedure according to the first high-frequency component separated by the first filter (23) while it detects the x-coordinate of the tip of the electronic pen (11) by a predetermined procedure according to the second high-frequency component separated by the second filter (22).
Claim 16
Dependent Claim
29 words
A display-integrated type tablet device as claimed in claim 15, wherein the frequencies of the first and the second high-frequency waves are not any odd multiple of each other.
Claim 17
Dependent Claim
139 words
A display-integrated type tablet device as claimed in claim 1, wherein the common drive circuit (2) generates during the display period a common electrode drive signal in which a high-frequency wave has been superimposed on a select pulse of the common electrode drive signal while the coordinate detection circuit (8, 9), having a filter for separating a high-frequency component of an induced voltage derived from the electronic pen (11), separates during the display period the high-frequency component of the induced voltage developed to the electrode of the electronic pen with the common electrode drive signal in which the high-frequency wave has been superimposed on the select pulse fed from the common drive circuit (2) by the filter, and detects the y-coordinate of the tip of the electronic pen (11) by a predetermined procedure according to the separated high-frequency component.
Claim 18
Dependent Claim
139 words
A display-integrated type tablet device as claimed in claim 7, wherein the common drive circuit (2) generates during the display period a common electrode drive signal in which a high-frequency wave has been superimposed on a select pulse of the common electrode drive signal while the coordinate detection circuit (8, 9), having a filter for separating a high-frequency component of an induced voltage derived from the electronic pen (11), separates during the display period the high-frequency component of the induced voltage developed to the electrode of the electronic pen with the common electrode drive signal in which the high-frequency wave has been superimposed on the select pulse fed from the common drive circuit (2) by the filter, and detects the y-coordinate of the tip of the electronic pen (11) by a predetermined procedure according to the separated high-frequency component.
Claim 19
Dependent Claim
138 words
A display-integrated type tablet device as claimed in claim 8, wherein the common drive circuit (2) generates during the display period a common electrode drive signal in which a high-frequency wave has been superimposed on a select pulse of the common electrode drive signal while the coordinate detection circuit (8, 9), having a filter for separating a high-frequency component of an induced voltage derived from the electronic pen (11), separates during the display period the high-frequency component of the induced voltage developed to the electrode of the electronic pen with the common electrode drive signal in which the high-frequency wave has been superimposed on the select pulse fed from the common drive circuit (2) by the filter, and detects the y-coordinate of the tip of the electronic pen by a predetermined procedure according to the separated high-frequency component.
Claim 20
Dependent Claim
139 words
A display-integrated type tablet device as claimed in claim 11, wherein the common drive circuit (2) generates during the display period a common electrode drive signal in which a high-frequency wave has been superimposed on a select pulse of the common electrode drive signal while the coordinate detection circuit (8, 9), having a filter for separating a high-frequency component of an induced voltage derived from the electronic pen 11, separates during the display period the high-frequency component of the induced voltage developed to the electrode of the electronic pen with the common electrode drive signal in which the high-frequency wave has been superimposed on the select pulse fed from the common drive circuit (2) by the filter, and detects the y-coordinate of the tip of the electronic pen (11) by a predetermined procedure according to the separated high-frequency component.
Claim 21
Dependent Claim
139 words
A display-integrated type tablet device as claimed in claim 13, wherein the common drive circuit (2) generates during the display period a common electrode drive signal in which a high-frequency wave has been superimposed on a select pulse of the common electrode drive signal while the coordinate detection circuit (8, 9), having a filter for separating a high-frequency component of an induced voltage derived from the electronic pen (11), separates during the display period the high-frequency component of the induced voltage developed to the electrode of the electronic pen with the common electrode drive signal in which the high-frequency wave has been superimposed on the select pulse fed from the common drive circuit (2) by the filter, and detects the y-coordinate of the tip of the electronic pen (11) by a predetermined procedure according to the separated high-frequency component.
Claim 22
Dependent Claim
139 words
A display-integrated type tablet device as claimed in claim 14, wherein the common drive circuit (2) generates during the display period a common electrode drive signal in which a high-frequency wave has been superimposed on a select pulse of the common electrode drive signal while the coordinate detection circuit (8, 9), having a filter for separating a high-frequency component of an induced voltage derived from the electronic pen (14), separates during the display period the high-frequency component of the induced voltage developed to the electrode of the electronic pen with the common electrode drive signal in which the high-frequency wave has been superimposed on the select pulse fed from the common drive circuit (2) by the filter, and detects the y-coordinate of the tip of the electronic pen (11) by a predetermined procedure according to the separated high-frequency component.
References Cited (Backward Citations)
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