(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2011/0216033 A1
`
`MAMBA et al. Sep. 8, 2011 (43) Pub. Date:
`
`
`US 20110216033A1
`
`(54) COORDINATE INPUT DEVICE AND DISPLAY
`DEVICE INCLUDING THE SAME
`
`(52) US. Cl. ........................................................ 345/174
`
`(75)
`
`Inventors:
`
`Norio MAMBA, Kawasaki (JP);
`Koji Nagata, Hachioji (JP); Koji
`Hayakawa, Chosei-gun (JP)
`
`(73) ASSIgnee:
`
`Hitachi Displays, Ltd'
`
`.
`(21) Appl. NO"
`.
`.
`Flled’
`
`(22)
`
`13/005’574
`
`Jan. 13’ 2011
`_
`_
`_
`_
`_
`Foreign Application Priority Data
`(30)
`Mar 2 2010
`(JP)
`2010 044877
`
`Publication Classification
`
`(51)
`
`Int. Cl,
`G06F 3/044
`
`(2006.01)
`
`(57)
`
`ABSTRACT
`
`Provided is a coordinate input device including: a coordinate
`input unit having a plurality of first detection electrodes and a
`plurality of second detection electrodes; an electrode drive
`circuit that applies a drive signal to one or more of the detec-
`tion electrodes; a capacitance detection circuit that detects a
`capacitance of the first and/or second detection electrode;
`means for selecting one or more ofthe detection electrodes to
`which the drive signal is not applied from among the detec-
`tion electrodes which are disposed in parallel to the detection
`electrodes to which the drive signal is applied, as a reference
`electrode; means for detecting a capacitance of the selected
`reference electrode; means for correcting a capacitance
`detection result of the capacitance detection circuit on the
`basis of the detected capacitance of the reference electrode;
`and an input coordinate computing circuit that calculates an
`input coordinate from the corrected capacitance detection
`result.
`
`
`
`
`
`
`106
`
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`
`Petitioner Samsung EX-1040, 0001
`RESP_0015274
`
`Petitioner Samsung Ex-1040, 0001
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 1 of 16
`
`US 2011/0216033 A1
`
`FIG.1
`
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`
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`RESP_0015275
`
`Petitioner Samsung Ex-1040, 0002
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 2 of 16
`
`US 2011/0216033 A1
`
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`RESP_0015276
`
`Petitioner Samsung Ex-1040, 0003
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 3 of 16
`
`US 2011/0216033 A1
`
`FIG.3
`
`REF
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`Petitioner Samsung EX-1040, 0004
`RESP_0015277
`
`Petitioner Samsung Ex-1040, 0004
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 4 of 16
`
`US 2011/0216033 A1
`
`FIG.4
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`
`Petitioner Samsung Ex-1040, 0005
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 5 of 16
`
`US 2011/0216033 A1
`
`FIG.5
`
`X1
`
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`
`Petitioner Samsung EX-1040, 0006
`RESP_0015279
`
`Petitioner Samsung Ex-1040, 0006
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 6 of 16
`
`US 2011/0216033 A1
`
`FIG.6
`
`X1
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`
`Petitioner Samsung EX-1040, 0007
`RESP_0015280
`
`Petitioner Samsung Ex-1040, 0007
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 7 of 16
`
`US 2011/0216033 A1
`
`FIG.7
`
`
`
`TOUCH1
`‘
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`
`Petitioner Samsung EX-1040, 0008
`RESP_0015281
`
`Petitioner Samsung Ex-1040, 0008
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 8 of 16
`
`US 2011/0216033 A1
`
`Tcycle
`
`3
`Tcycle
`_
`FIG.8 Em Ty2 Ty3 Ty4 Ty5 TysE
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`Petitioner Samsung EX-1040, 0009
`RESP_0015282
`
`Petitioner Samsung Ex-1040, 0009
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 9 of 16
`
`US 2011/0216033 A1
`
`DREF
`
`DXI DXZ D)_(3 D)_(4 DX5 DXS DX7 DXS
`
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`
`Petitioner Samsung EX-1040, 0010
`RESP_0015283
`
`Petitioner Samsung Ex-1040, 0010
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 10 of 16
`
`US 2011/0216033 A1
`
`FIG.12
`
`
`SCANNING
`PERIOD
`
`DRIVE
`ELECTRODE
`
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`
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`
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`
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`
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`
`FIG.13
`
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`Sgégrgge
`
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`(THREE)
`(FOUR)
`
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`
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`
`Petitioner Samsung Ex-1040, 001 1
`RESP_0015284
`
`
`
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`
`Petitioner Samsung Ex-1040, 0011
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 11 of 16
`
`US 2011/0216033 A1
`
`
`
`III-III-
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`
`Petitioner Samsung Ex-1040, 0012
`RESP_0015285
`
`Petitioner Samsung Ex-1040, 0012
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 12 of 16
`
`US 2011/0216033 A1
`
`FIG.15
`
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`Petitioner Samsung EX-1040, 0013
`RESP_0015286
`
`Petitioner Samsung Ex-1040, 0013
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 13 of 16
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`US 2011/0216033 A1
`
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`Petitioner Samsung Ex-1040, 0014
`RESP_0015287
`
`Petitioner Samsung Ex-1040, 0014
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 14 of 16
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`US 2011/0216033 A1
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`
`
`
`
`Petitioner Samsung EX-1040, 0015
`RESP_0015288
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`Petitioner Samsung Ex-1040, 0015
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 15 of 16
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`US 2011/0216033 A1
`
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`RESP_0015289
`
`Petitioner Samsung Ex-1040, 0016
`
`

`

`Patent Application Publication
`
`Sep. 8, 2011 Sheet 16 of 16
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`US 2011/0216033 A1
`
`SCN_X1 I
`
`
`
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`
`Petitioner Samsung EX-1040, 0017
`RESP_0015290
`
`Petitioner Samsung Ex-1040, 0017
`
`

`

`US 2011/0216033 A1
`
`Sep. 8, 2011
`
`COORDINATE INPUT DEVICE AND DISPLAY
`DEVICE INCLUDING THE SAME
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`
`[0001] The present application claims priority from Japa-
`nese application JP2010-044877 filed on Mar. 2, 2010, the
`content ofwhich is hereby incorporated by reference into this
`application.
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`[0002]
`[0003] The present invention relates to a coordinate input
`device that detects an indication point on a screen, and a
`display apparatus having the same. More particularly, it is
`relates to a technique which is effective in increasing the
`coordinate detection precision of a display apparatus having a
`capacitive coupling type coordinate input device.
`[0004]
`2. Description of the Related Art
`[0005] A display apparatus having a detection device (here-
`inafter, also called a touch sensor or a touch panel) having a
`screen input function for inputting information by a touch
`operation (contact pressing operation, hereinafter, simply
`called a touch) using a finger or the like of a user on the
`display screen is used for mobile electronic devices such as
`PDAs and portable terminals, various electronic appliances,
`and stationary customer guide terminals such as unattended
`reception machines. As such a touch input device, a resistive
`type that detects a change in resistance of a touched portion,
`a capacitive coupling type that detects a change in capaci-
`tance, an optical sensor type that detects a change in light
`intensity of a portion blocked by a touch, and the like are
`known.
`
`In such typcs, recently, a capacitive coupling typc
`[0006]
`touch panel has been spotlighted. In a case where a touch is
`input to an input device using a button, a slider, or the like
`displayed on a display apparatus of a mobile electronic
`device, the input device needs to be disposed on the front
`surface ofa display panel. In this case, an input function needs
`to be incorporated therein while maintaining a display image
`quality by minimizing a reduction in display luminance ofthe
`display apparatus. Here, in general, the resistive or the optical
`sensor type has a low transmittance of about 80%; however,
`the capacitive coupling type has a hightransmittance of about
`90%. Accordingly, the capacitive coupling type is advanta-
`geous in that the display image quality is not degraded. In
`addition, the resistive type senses a touch position by a
`mechanical contact of a resistance film. Therefore, the num-
`ber of touches (mechanical contact) is increased, and the
`resistance film may be deteriorated or broken, so that there is
`a problem in that detection errors increase or detection fail—
`ures may occur. On the other hand, the capacitive coupling
`type has no mechanical contact such as the contact of a
`detection electrode with other electrodes, and thus is advan-
`tageous in terms of durability.
`[0007] As a capacitance detection circuit in the capacitive
`coupling type, for example, a type is disclosed in JP2005-
`140612 A. In the disclosed type, a sensor unit having a plu-
`rality of row wires and a plurality of intersecting column
`wires detects the capacitance existing in the vicinity of inter-
`sections thereof. When the pitch between the row wires and
`the column wires is reduced, fingerprint detection can be
`performed by detecting a change in capacitance that occurs
`
`due to unevenness of a surface of a fingerprint. On the other
`hand, as the sensor unit is made transparent and to have the
`same size as a screen of a display panel, a coordinate input
`device using a finger or the like as input means can be imple-
`mented. Capacitance detection is performed by applying a
`drive signal to the row wires sequentially selected from
`among the plurality ofrow wires from a row wire driving unit,
`and detecting a current flowing via the capacitance in the
`vicinity of an intersection between the row wire to which the
`drive signal is applied and the column wire, by using a capaci-
`tance detection circuit. Here, the capacitance detection circuit
`detects a capacitance on the basis of the difference of two
`detection current results. In the disclosed type, two means are
`disclosed for enhancing the capacitance detection precision
`by reducing external noise.
`[0008]
`In the first means, from among column electrodes
`intersecting row electrodes that apply the drive signal, the
`column electrode which initially detects the capacitance in
`the vicinity of an intersection thereof compares the detected
`current to a reference current flowing through a reference
`capacitance of the capacitance detection circuits and calcu-
`lates a capacitance, thereby enhancing the capacitance detec-
`tion precision. The capacitance detection of the column elec-
`trode thereafter is performed by obtaining the difference
`between the detection currents of the adjacent column elec-
`trodes. In a case where capacitance detection of the row
`electrodes is performed after detecting the capacitances of all
`the column electrodes,
`the above-described operation is
`repeated.
`In the second means, one is selected as a capacitance
`[0009]
`detection object from among the column electrodes to detect
`the detection current flowing through the corresponding col-
`umn electrode, and the second detection current flowing
`through a plurality of the column electrodes excluding the
`corresponding column electrode is regarded as a reference
`current. Here, capacitances in the vicinities of the intersec-
`tions thereof are detected by differences between the detec—
`tion currents which are capacitance detection objects and the
`reference current.
`
`SUMMARY OF THE INVENTION
`
`[0010] Here, the capacitance detection precision in a case
`where a sensor unit of a coordinate input device is transparent
`and a display panel is installed under the sensor unit will be
`described.
`[0011] Aplurality of scanning lines and a plurality of signal
`lines that supply an image signal to pixels on the selected
`scanning lines exist on a screen of the display panel. Insula-
`tors exist between the signal lines and the scanning lines on
`the screen of the display panel and between row electrodes
`and column electrodes in the sensor unit of the coordinate
`
`input device, so that parasitic capacitance occurs.
`[0012] Here, a scanning signal used to rewrite an image is
`applied to the scanning line, and the corresponding image
`signal voltage is applied to the signal line used to rewrite the
`image of the selected scanning line. Accordingly, in the row
`electrodes or the column electrodes of the sensor unit which
`
`is coupled to the scanning lines or the signal lines via parasitic
`capacitance, charge or discharge currents that occur due to a
`change in image signal voltage of scanning signal voltage are
`incorporated as noise.
`[0013] Here, in a method using a reference capacitance
`disclosed as the first means in JP2005-140612 A, when the
`capacitance in the vicinity of the intersection of the first
`
`Petitioner Samsung Ex-1040, 0018
`RESP_0015291
`
`Petitioner Samsung Ex-1040, 0018
`
`

`

`US 2011/0216033 A1
`
`Sep. 8, 2011
`
`column electrode is detected, the capacitance is calculated by
`the difference between a detection current of the first column
`
`electrode and a reference current that flows through a refer-
`ence capacitance that a capacitance detection circuit holds. In
`this case, noise is not incorporated from the display panel to
`the reference current. On the other hand, noise is incorporated
`to the first column electrode, so that the capacitance value
`corresponding to the first column electrode obtained by the
`difference between the two is a value into which a noise
`
`component is incorporated. The noise component from the
`display panel sequentially changes due to a displayed image
`or the like and thus varies in the row electrodes driving.
`Therefore, the detection precision ofthe detected capacitance
`value is degraded, so that the input coordinate precision based
`on the calculation is also degraded.
`[0014]
`In addition, in the method disclosed as the second
`means in JP2005-140612A for regarding the current of the
`plurality ofthe column electrodes excluding the column elec-
`trode which is the capacitance detection object as the refer-
`ence current, since noise is incorporated from the display
`panel to both the detection current and the reference current,
`the noise from the display panel can be reduced by calculating
`the difference. Here, in a case where a change in capacitancc
`occurs due to an input to the plurality ofthe column electrodes
`which detect the reference current, the reference current is
`changed. Accordingly, in the case where the reference current
`is changed due to an existence of an input or a change in an
`input space, the capacitance detection result is changed due to
`the difference, so that it is difficult to always detect the capaci-
`tance with good precision.
`[0015] As described above, in the existing coordinate input
`device, it is difficult to always detect the capacitance with
`good precision by reducing random noise incorporated from
`the display panel, unfortunately.
`[0016] Therefore, an object of the invention is to provide a
`technique capable of enhancing the capacitance detection
`precision by reducing random noise incorporated from a dis-
`play panel.
`[0017]
`(1) In order to solve the problem, a coordinate input
`device includes: a coordinate input unit having a plurality of
`first detection electrodes and a plurality of second detection
`electrodes intersecting the first detection electrodes; an elec-
`trode drive circuit that applies a drive signal to one or more of
`the first and/or second detection electrodes; a capacitance
`detection circuit that detects a capacitance of the first and/or
`second detection electrode in synchronization with the drive
`signal; means for selecting one or more of the detection
`electrodes to which the drive signal is not applied from among
`the detection electrodes which are disposed in parallel to the
`detection electrodes to which the drive signal is applied, as a
`reference electrode; means for detecting a capacitance of the
`selected reference electrode; means for correcting a capaci-
`tance detection result of the capacitance detection circuit on
`the basis of the detected capacitance of the reference elec-
`trode; and an input coordinate computing circuit that calcu-
`lates an input coordinate from the corrected capacitance
`detection result.
`
`(2) In order to solve the problem, a display apparatus
`[0018]
`includes: a display panel that displays an image based on an
`image signal from an external system; and a coordinate input
`device disposed on the display surface side of the display
`panel, wherein the coordinate input device includes a coordi-
`nate input unit in which a plurality of first detection electrodes
`and a plurality of second detection electrodes intersecting the
`
`first detection electrodes are formed, and which is disposed
`on the display surface side of the display panel, an electrode
`drive circuit that applies a drive signal to one or more of the
`first and/or second detection electrodes, a capacitance detec-
`tion circuit that detects a capacitance ofthe first and/or second
`detection electrode in synchronization with the drive signal,
`means for selecting one or more of the detection electrodes to
`which the drive signal is not applied from among the detec-
`tion electrodes which are disposed in parallel to the detection
`electrodes to which the drive signal is applied, as a reference
`electrode, means for detecting a capacitance of the selected
`reference electrode, means for correcting a capacitance
`detection result of the capacitance detection circuit on the
`basis of the detected capacitance of the reference electrode,
`and an input coordinate computing circuit that calculates an
`input coordinate from the corrected capacitance detection
`result.
`
`[0019] According to the invention, random noise incorpo-
`rated from the display panel can be reduced, thereby enhanc-
`ing the capacitance detection precision.
`[0020] The other advantages of the invention will be more
`apparent from the entire description.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a block diagram for explaining the entire
`[0021]
`configuration of a display apparatus according to a first
`embodiment of the invention.
`
`FIG. 2 is a diagram for explaining a schematic con-
`[0022]
`figuration of a selective electrode drive circuit in the display
`apparatus according to the first embodiment of the invention.
`[0023]
`FIG. 3 is a diagram for explaining a schematic con-
`figuration of a capacitance dctcction circuit in the display
`apparatus according to the first embodiment of the invention.
`[0024]
`FIG. 4 is a timing chart of voltage waveforms of
`selective electrodes Y_SENS and control signals included in
`a timing control signal group TMG in the display apparatus
`according to the first embodiment of the invention.
`[0025]
`FIG. 5 is a schematic diagram of a case where a
`contact of a finger or the like does not exist in a coordinate
`input device according to the first embodiment of the inven-
`tion.
`
`FIG. 6 is a schematic diagram of a case where a
`[0026]
`finger or the like is in contact with the coordinate input device
`according to the first embodiment of the invention.
`[0027]
`FIG. 7 is a schematic diagram of a case where a
`contact exists on a coordinate input unit according to the first
`embodiment of the invention.
`[0028]
`FIG. 8 is a timing chart illustrating voltage wave-
`forms of selective electrodes, control signals, and the like in
`the case where the contact exists as illustrated in FIG. 7.
`
`FIG. 9 is a schematic diagram of the strength of the
`[0029]
`digital output signals in a first cycle Tcycle illustrated in FIG.
`8.
`
`FIG. 10 is a schematic diagram ofthe strength ofthe
`[0030]
`digital output signals in a second cycle Tcycle illustrated in
`FIG. 8.
`
`FIG. 11 is a schematic diagram ofthe strength ofthe
`[0031]
`digital output signals after a correction process is performed
`in the coordinate input device according to the first embodi-
`ment of the invention.
`
`FIG. 12 is a diagram for explaining another selec-
`[0032]
`tion method of the reference electrode used in the coordinate
`input device according to the first embodiment of the inven-
`tion.
`
`Petitioner Samsung Ex-1040, 0019
`RESP_0015292
`
`Petitioner Samsung Ex-1040, 0019
`
`

`

`US 2011/0216033 A1
`
`Sep. 8, 2011
`
`FIG. 13 is a diagram for explaining another selec-
`[0033]
`tion method of the reference electrode used in the coordinate
`
`input device according to the first embodiment of the inven-
`tion.
`
`FIG. 14 is a block diagram for explaining the entire
`[0034]
`configuration of a display apparatus according to the second
`embodiment.
`
`FIG. 15 is a diagram for explaining a schematic
`[0035]
`configuration of the other capacitance detection circuit in the
`display apparatus according to the second embodiment of the
`invention.
`
`FIG. 16 is a diagram for explaining a schematic
`[0036]
`configuration of the one capacitance detection circuit in the
`display apparatus according to the second embodiment of the
`invention.
`[0037]
`FIG. 17 is a timing chart of voltage waveforms of
`selective electrodes Y_SENS and detection electrodes
`X_SENS and control signals included in a timing control
`signal group TMG in the display apparatus according to the
`second embodiment of the invention.
`
`FIG. 18 is a schematic diagram for explaining signal
`[0038]
`paths of the detection electrode X1 at a scanning period Tx1
`in the coordinate input device according to the second
`embodiment of the invention.
`[0039]
`FIG. 19 is a schematic diagram for explaining signal
`paths of the detection electrodes X3 in the scanning period
`Tx1 in the coordinate input device according to the second
`embodiment of the invention.
`
`FIG. 20 is a timing chart of the selection timing
`[0040]
`signals and the digital output signals DX, DREFX, DY, and
`
`DREFY in the single cycle in the display apparatus according
`to the second embodiment of the invention.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`[0041] Hereinafter, exemplary embodiments of thc inven-
`tion will be described with reference to the accompanying
`drawings. It should be noted that, throughout the drawings for
`describing the embodiments, the components which have
`identical or similar functions are denoted by the same refer-
`ence symbols, and the repetitive description thereof is omit-
`ted.
`
`First Embodiment
`
`[Entire Configuration]
`[0042]
`FIG. 1 is a block diagram for explaining the entire
`configuration of a display apparatus according to a first
`embodiment of the invention. Hereinafter, the entire configu-
`ration of the display apparatus according to the first embodi-
`ment will be described with reference to FIG. 1. Here, since a
`configuration of the display panel is the same as that of a
`display panel according to the related art, a coordinate input
`device will be described in detail in the following description.
`In addition, x and y in the figure represent x and y axes.
`Moreover, the display panel according to the first embodi-
`ment may be any one of non-light-emitting display panels
`such as a liquid crystal display panel and self-light-emitting
`display panels such as an organic EL display panel.
`[0043] As illustrated in FIG. 1,
`the display apparatus
`according to the first embodiment includes a display panel
`106 that displays an image based on display data (not shown)
`input from a system 105 which is an external apparatus, and
`a coordinate input device having a coordinate input unit 101
`disposed on the display surface side of the display panel 106.
`
`The coordinate input device includes the coordinate input unit
`101 that indicates an input position, a selective electrode drive
`circuit 102 needed to detect input coordinates, a capacitance
`detection circuit 103, and an input coordinate computing
`circuit 104. Data DATA such as the input coordinates detected
`by the coordinate input device is output to the system 105 of
`an apparatus including the coordinate input device and the
`display apparatus using the same, and the system 105 displays
`display contents or the like corresponding to an input on the
`display panel 106. In addition, in a case where the display
`apparatus 106 is installed under the coordinate input unit 101,
`that is, on the rear surface side thereof, it is preferable that the
`coordinate input 1mit 101 be transparent such that image
`contents displayed on the display apparatus 106 are seen by
`an operator.
`[0044]
`In order to detect coordinates due to an input, the
`coordinate input unit 101 of the first embodiment includes a
`plurality ofdetection electrodes (second detection electrodes)
`X_SENS extending in a y direction in parallel to an x direc-
`tion, and a plurality of selective electrodes (first detection
`electrodes)Y_SENS extending in the x direction in parallel to
`the y direction. The detection electrodes X_SENS and the
`selective electrodes Y_SENS intersect. In order to increase a
`transmitting property of the coordinate input unit 101, it is
`preferable that the detection clcctrodcs X_SENS and the
`selective electrodes Y_SENS be transparent. In addition, in
`FIG. 1, a case where the number of selective electrodes
`Y_SENS is 6, and the number of detection electrodes
`X_SENS is 8 is illustrated; however, the number ofelectrodes
`is not limited thereto.
`
`[0045] The selective clcctrodc drivc circuit 102 according
`to the invention is connected to the selective electrodes
`Y_SENS with selective electrode wires Y1 to Y6. The selec-
`tive electrode drive circuit 102 selects one or more from
`
`among the plurality of selective electrodes Y_SENS by a
`timing control signal group TMG output from the input coor-
`dinate computing circuit 104 and sequentially applies the
`drive signal. In addition, the selective electrode drive circuit
`102 selects one or more from among the selective electrodes
`Y_SENS to which the drive signal is not applied as reference
`electrodes, and connects it or them to a reference signal wire
`REF.
`
`In addition, the capacitance detection circuit 103 is
`[0046]
`also controlled by the timing control signal group TMG. The
`capacitance detection circuit 103 detects two types of signals
`including a signal from the selective electrode Y_SENS
`selected by the selective electrode drive circuit 102 as the
`reference electrode and a signal that is changed by the capaci-
`tance in the vicinity of an intersection between the selective
`electrode Y_SENS to which the drive signal is applied by the
`selective electrode drive circuit 102 and the plurality of detec-
`tion electrodes X_SENS. The signal from the reference elec-
`trode and the signal changed by the capacitance in the vicinity
`of the intersection are respectively input to the capacitance
`detection circuit 103 via the reference signal wire REF and
`detection electrode wires X1 to X8. That is, the signal input
`from the reference electrode selected by the selective elec-
`trode drive circuit 102 is input to the capacitance detection
`circuit 103. The capacitance detection circuit 103 generates
`digital output signals DREF and DX1 to DXS from the signals
`input via the reference signal wire REF and the detection
`signal wires X1 to X8 so as to be output to the input coordinate
`computing circuit 104.
`
`Petitioner Samsung Ex-1040, 0020
`RESP_0015293
`
`Petitioner Samsung Ex-1040, 0020
`
`

`

`US 2011/0216033 A1
`
`Sep. 8, 2011
`
`[0047] The input coordinate computing circuit 104 calcu-
`lates a correction amount that cancels noise components from
`the digital output signal DREF, calculates input coordinates
`from data obtained by cancelling the noise components from
`the digital output signals DXl to DX8, and outputs the
`obtained input coordinates to the system 105.
`
`[Configuration of Selective Electrode Drive Circuit]
`
`FIG. 2 is a diagram for explaining a schematic con-
`[0048]
`figuration ofthe selective electrode drive circuit in the display
`apparatus according to the first embodiment of the invention.
`Hereinafter,
`the selective electrode drive circuit will be
`described with reference to FIG. 2.
`
`[0049] As illustrated in FIG. 2, the selective electrode drive
`circuit 102 according to the first embodiment includes a plu-
`rality of drive circuits 201 that selects one or more from
`among the plurality of selective electrodes Y_SENS and
`applying the drive signal to the selected selective electrodes,
`control switches DSL_Y1 to DSL_Y6, and control switches
`RSL_Y1 to RSL_Y6 that selects the selective electrodes
`Y_SENS as the reference electrodes. The drive circuit 201
`outputs the drive signal at periods (hereinafter, referred to as
`timing periods) that can be detected by selective timing sig-
`nals SCN_Yl to SCN_Y6 included in the timing control
`signal group TMG. Here, the drive signal output from the
`drive circuit 201 in the scanning periods may be a voltage
`drive signal or a current drive signal. In addition, the drive
`signal output may be output once or a plurality oftimes in the
`signal scanning period. Moreover,
`it is preferable that an
`arbitrary constant voltage be applied by the drive circuits 201
`to the selective electrodes to which the drive signal is not
`applied.
`[0050] As such, the selective electrode drive circuit 102
`sequentially drives the selective electrodes Y_SENS of the
`coordinate input unit 101 by the drive circuits 201. On the
`other hand, one or more ofthe selective electrodesY_SENS to
`which the drive signal is not applied by the drive circuits 201
`are selected by the control switches RSL as the reference
`electrodes. Here, the control switches DSL corresponding to
`the selective electrodes Y_SENS selected as the reference
`electrodes are 011 a non-selected state. The reference elec-
`
`trodes selected by the control switches RSL are connected to
`the reference signal wire REF, and the signals detected from
`the selected rcfcrcncc electrodes are output to the reference
`signal wire REF.
`
`[Configuration of Capacitance Detection Circuit]
`
`FIG. 3 is a diagram for explaining a schematic con-
`[0051]
`figuration of the capacitance detection circuit in the display
`apparatus according to the first embodiment of the invention.
`Hereinafter,
`the capacitance detection circuit will be
`described with reference to FIG. 3.
`
`[0052] As illustrated in FIG. 3, the capacitance detection
`circuit 103 includes signal detection circuits 301 that detects
`signals input via the reference signal wire REF and the detec-
`tion signal wires X1 to X8, andAD conversion circuit 302 that
`converts analog output signals AREF andAXl to AX8 output
`from the signal detection circuits 301 into digital signals
`
`DREF and DXl to DX8. The signal detection circuits 301 are
`reset by a reset control signal RES included in the timing
`control signal group TMG before detecting the signals.
`Thereafter, at a period at which the selective electrode drive
`circuit 102 applies the drive signal to the selective electrode,
`
`the signals transmitted via the reference signal wire REF and
`the detection electrode wires X1 to X8 are detected. Here, A
`voltage or a current transmitted from each electrode may be
`detected by the signal detection circuit 301. The signal detec-
`tion circuit 301 samples and holds the analog signal detected
`by the period at which the