Abstract:
A display device includes a display panel, a touch panel control unit, a plurality of scanning electrodes formed on the display panel, a plurality of detection electrodes formed on the display panel so as to intersect with the plurality of scanning electrodes, a drive signal supply unit for inputting a drive signal to each of the scanning electrodes, and a detection unit for detecting a detection signal from each of the detection electrodes. The touch panel control unit supplies the driving signal to each of the scanning electrodes from the drive signal supply unit to enable detection of a touch position of a detection object based on the detection signal detected, and supplies the driving signal to all of the scanning electrodes collectively from the drive signal supply unit to enable detection of approach of the detection object to the touch panel based on the detection signal detected.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 14/946,332, filed Nov. 19, 2015, which is a continuation of U.S. application Ser. No. 14/526,945 (now U.S. Pat. No. 9,223,434), filed Oct. 29, 2014, which is a continuation application of U.S. application Ser. No. 13/851,144(now U.S. Pat. No. 8,878,768), filed Mar. 27, 2013, the contents of which are incorporated herein by reference. 
     The present application claims priority from Japanese application No. 2012-095405 filed on Apr. 19, 2012, the content of which is hereby incorporated by reference into this application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display device, particularly, to a technique that is effective for the application to a display device equipped with a touch panel in which a liquid crystal panel is equipped with a touch panel function. 
     2. Description of the Related Art 
     A display device including a device referred to as a touch sensor or a touch panel, which performs a touch operation (a contact pressing operation, hereinafter, simply referred to as a touch) on a display screen using a finger of a user, a pen or the like to input information, has been used for a mobile electronic apparatus such as a PDA and a portable terminal, various home electric appliances, an automated teller machine or the like. As such a touch panel, a resistive membrane type of detecting a resistance valve change of a touched portion, an electrostatic capacity type of detecting a change of the capacity, an optical sensor type of detecting a change of an amount of light or the like have been known. 
     The touch panel of the electrostatic capacity type is provided with scanning electrodes (Y electrodes) for a drive signal application placed lengthwise and breadthwise in a two dimensional matrix form, and detection electrodes (an X electrodes) for signal detection perpendicular to the scanning electrodes, and the capacity of each electrode is detected in an input processing unit. When a conductor such as a finger comes into contact with the surface of the touch panel, since the capacity of each electrode increases, the input processing unit detects the increase, and calculates the input coordinate on the basis of the signal of the change of the capacity detected by each electrode. 
     SUMMARY OF THE INVENTION 
     For example, in the touch panel-integrated display device in which the touch panel is built in the liquid crystal display panel, a common electrode for display (also referred to as a counter electrode) originally included in the liquid crystal display panel is also used as one electrodes (drive electrodes) of a pair of electrodes for touch sensor, and the other electrodes (detection electrodes for sensor) thereof is formed on a glass substrate. 
     In such a touch panel-integrated display device, a new usage method is assumed in which, if it is possible to detect the approach of a finger (an detection object) of a user, when the finger of the user approaches, a menu screen is displayed on the display screen of the touch panel-integrated display device. 
     When assuming such a usage method, in the touch panel-integrated display device, it is requested that a detection circuit, which is used for a type of performing the high-precision coordinate detection (hereinafter, also referred to as a mutual detection) which uses the change of the electrostatic capacity between the common electrode and the detection electrode due to the influence of a finger of a user, can also be used for a type of detecting the presence or absence of the approach of the detection object without coordinate information (hereinafter, also referred to as a self detection) which uses a change of an earth capacity of the detection electrode due to the influence of a finger of a user. 
     The invention was based on the above-mentioned demand, and an object thereof is to provide a technique that makes the detection circuit, which is used for the mutual detection, also be used for the self detection, in the touch panel-integrated display device. 
     The above-mentioned and other objects and new characteristics of the invention will be clarified by the description of the specification and the attached drawings. 
     A representative summary of the inventions disclosed in the present application will be briefly described as below. 
     (1) According to an aspect of the invention, there is provided a display device that includes a display panel, and a touch panel integrated in the display panel, wherein the touch panel has a plurality of scanning electrodes formed on the display panel; a plurality of detection electrodes that is formed on the display panel and intersects with the plurality of scanning electrodes; drive signal supply unit for inputting a drive signal to each of the scanning electrodes; detection unit for acquiring a detection signal from each of the detection electrodes; touch position detection unit for detecting a touch position of an detection object, based on the detection signal detected from each of the detection unit, when the drive signal is sequentially input to each of the scanning electrodes from the drive signal supply unit; and approach detection unit for detecting that the detection object approaches the touch panel, based on the detection signal detected from each of the detection unit, when a scanning voltage is collectively input to all the scanning electrodes from the drive signal supply unit. 
     (2) In the display device according to (1), the drive signal supply unit has a switching element S 1  that supplies a drive voltage Vtxh to each of the plurality of scanning electrodes, and a switching element S 2  that supplies a drive voltage Vtxl (Vtxl&lt;Vtxh) to each of the plurality of scanning electrodes, the detection unit has an integration circuit in which a reference voltage Vref is input to one terminal, a switching element S 3  that is connected between each of the detection electrodes and the other terminal of the integration circuit, and a switching element S 4  that is connected between each of the detection electrodes and the one terminal of the integration circuit, the switching element S 1  and the switching element S 2  are provided for each of the scanning electrodes, and the integration circuit, the switching element S 3  and the switching element S 4  are provided for each of the detection electrodes. 
     (3) In the display device according to (2), a touch position detection period of the detection object has a reset period and a detection period for each of the scanning electrodes, in the reset period in a scanning electrode of a scanning target to which the drive signal is input, the switching element S 1  of the scanning electrode of the scanning target is turned off, the switching element S 2  of the scanning electrode of the scanning target is turned on, the switching element S 1  and the switching element S 2  of the scanning electrode other than the scanning target are turned off, the switching elements S 3  of all the detection electrodes are turned off, and the switching elements S 4  of all the detection electrodes are turned on, the capacity between the scanning electrode of the scanning target and all the detection electrodes is charged with a voltage of (Vref−Vtxl), in the detection period, the switching element S 1  of the scanning electrode of the scanning target is turned on, the switching element S 2  of the scanning electrode of the scanning target is turned off, the switching element S 1  and the switching element S 2  of the scanning electrode other than the scanning target are turned off, all the switching elements S 3  are turned on, all the switching elements S 4  are turned off, and the electric current flowing in the capacity between the scanning electrode of the scanning target and all the detection electrodes is integrated by the integration circuit provided for each of the detection electrodes, and the touch position detection unit detects the touch position of the detection object, based on the output voltage of the integration circuit provided for each of the detection electrodes. 
     (4) In the display device according to (2), the approach detection period of the detection object has a reset period, a charge period, and a detection period, during the reset period, the switching elements S 1  of all the scanning electrodes are turned off, the switching elements S 2  of all the scanning electrode are turned on, the switching elements S 3  of all the detection electrodes are turned off, and the switching elements S 4  of all the detection electrodes are turned on, the capacity between all the scanning electrodes and all the detection electrodes is charged with a voltage of (Vref−Vtxl), during the charge period, the switching elements S 1  of all the scanning electrodes are turned on, the switching elements S 2  of all the scanning electrodes are turned off, the switching elements S 3  of all the detection electrodes are turned off, and the switching elements S 4  of all the detection electrodes are turned off, the capacity between all the scanning electrodes and each of the detection electrodes is charged with a voltage of (Vref−Vtxl+Vtxh), during the detection period, the switching elements S 1  of all the scanning electrodes are turned on, the switching elements S 2  of all the scanning electrodes are turned off, the switching elements S 3  of all the detection electrodes are turned on, and the switching elements S 4  of all the detection electrodes are turned off, the capacity between all the scanning electrodes and each of the detection electrodes is integrated by the integration circuit provided for each of the detection electrodes, and the approach detection unit detects that the detection object approach, based on the output voltage of the integration circuit provided for each of the detection electrodes. 
     Effects obtained by the representative aspect of the inventions disclosed in the present application are described as follows. 
     According to the invention, in the touch panel-integrated display device, the detection circuit used for the mutual detection can also be used for the self detection. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  are views that describe a touch panel display device of the related art. 
         FIGS. 2A and 2B  are views that describe the touch panel shown in  FIGS. 1A and 1B . 
         FIG. 2C  is a view that describes a detection sequence of the touch panel shown in  FIGS. 1A and 1B . 
         FIGS. 3A and 3B  are views that describe a display device equipped with a touch panel of the related art. 
         FIGS. 4A and 4B  are views for describing the touch panel shown in  FIGS. 3A and 3B . 
         FIGS. 5A, 5B and 5C  are views that describe a detection principle of a liquid crystal touch panel-integrated display device having the structure shown in  FIGS. 4A and 4B . 
         FIGS. 6A and 6B  are views that describe a mutual detection in the touch panel-integrated display device. 
         FIGS. 7A and 7B  are views that describe the control of the self detection of the present example in the touch panel-integrated display device. 
         FIGS. 8A and 8B  are views that describe the detection state of the self detection of the present example in the touch panel-integrated display device. 
         FIG. 9  is a perspective view that shows a more specific configuration of the touch panel-integrated display device of an example of the invention. 
         FIG. 10  is a view that describes a counter electrode and a detection electrode in the liquid crystal touch panel-integrated display device shown in  FIG. 9 . 
         FIG. 11  is a cross-sectional view that shows a part of a cross section of a display unit of the liquid crystal touch panel-integrated display device shown in  FIG. 9  in an enlarged manner. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, an example of the invention will be described in detail referring to the drawings. 
     In addition, in the whole drawings for describing the example, elements having the same functions are denoted by the same reference numerals, and the repeated description will be omitted. Furthermore, the following example does not limit the interpretation of the claims of the invention. 
     Summary of Touch Panel of Related Art 
       FIGS. 1A and 1  B are views for describing a touch panel display device of the related art. 
       FIG. 1A  is a block diagram that shows a schematic configuration of the touch panel display device of the related art, and  FIG. 1B  is a view that shows a structure of the touch panel display device of the related art. 
     In the touch panel display device shown in  FIGS. 1A and 1B , as shown in  FIG. 1B , an electrostatic capacity type touch panel  106  is bonded on a display panel (herein, a liquid crystal display panel)  101  by an adhesive  110 . As will be described later, the touch panel  106  has a Y electrode for drive signal application (a scanning electrode) and an X electrode for signal detection (a detection electrode) perpendicular to the Y electrode. 
     The touch panel  106  is provided on a front surface of the display panel  101 . Thus, when a user sees images displayed on the display panel  101 , since the display images need to penetrate the touch panel  106 , it is preferable that the touch panel  106  have high optical transmittance. 
     The X electrode and the Y electrode of the touch panel  106  are connected to a touch panel control unit  108  through a wiring  107 . 
     The touch panel control unit  108  sequentially applies the drive signal using the Y electrode as a scanning electrode, and measures the capacity between the electrodes on an intersection point of each electrode using the X electrode as a detection electrode, and calculates and obtains the input coordinates from the capacity detection signal that changes according to the capacity value of the point of intersection between the respective electrodes. 
     The touch panel control unit  108  transmits the input coordinate to a system control unit  105  using an I/F signal  109 . 
     When the input coordinate is transmitted from the touch panel  106  by the touch operation, the system control unit  105  generates the display image depending on the touch operation, and transmits the display image to a display control circuit  103  as a display control signal  104 . 
     The display control circuit  103  generates a display signal  102  depending on the display image transmitted by the display control signal  104 , and displays the images on the display panel  101 . 
     In addition, as the display panel, a panel capable of using the touch panel  106  may be used, and a display panel that uses an organic light emitting diode element and a surface conduction type electron emission element, an organic EL display panel or the like can also be used, without being limited to a liquid crystal display panel. 
       FIGS. 2A and 2B  are views for describing the touch panel  106  shown in  FIGS. 1A and 1B . 
       FIG. 2A  is a view that shows an electrode pattern of the touch panel  106  shown in  FIGS. 1A and 1B , and  FIG. 2B  is a cross-sectional view that shows a cross-sectional structure along a cut line A-B of  FIG. 2A . 
     As shown in  FIG. 2A , the touch panel  106  shown in  FIGS. 1A and 1B  has an X electrode  201  and a Y electrode  202  for detecting the capacity. Herein, for example, although five X electrodes  201  and six Y electrodes  202  are shown, the number of the electrodes is not limited thereto. 
     In  FIG. 2B , reference numeral  204  is a touch panel substrate formed of a glass substrate, a PET film or the like. The touch panel  106  shown in  FIGS. 1A and 1B  is configured so that the X electrode  201  and the Y electrode  202  are formed on the touch panel substrate  204 , and a protective membrane  203  is formed on the X electrode  201  and the Y electrode  202 . Furthermore, in  FIG. 2B , a shield electrode  205  is formed on a surface of the display panel side of the touch panel substrate  204 . 
       FIG. 2C  is a view for describing the detection sequence of the touch panel  106  shown in  FIGS. 1A and 1  B, and for describing the detection sequence when there is no input to the touch panel  106 . Furthermore,  FIG. 2C  is a wave form view. In the wave form view shown in  FIG. 2C , a horizontal axis indicates a time and a vertical axis indicates amplitude. 
     As shown in  FIG. 2C , a drive voltage (a drive pulse)  401  is sequentially applied to the Y electrode  202  of TX 1  to TX 6  for each scanning period. On the contrary, the wave form of a detection signal  402  detected by the X electrode  201  of RX 1  to RX 5  changes in synchronization with the input of the drive voltage. In  FIG. 2C , since there is no input to the touch panel  106 , the amplitude of the detection signal detected by the X electrode  201  of RX 1  to RX 5  is not greatly changed. 
     In addition, as shown in A of  FIG. 2C , the drive signal (the input pulse)  401  which is sequentially input to the Y electrode  202  of TX 1  to TX 6  for each detection period is a plurality of pulse rows. Similarly, as shown in B of  FIG. 2C , the detection signal  402  detected by the X electrode  201  of RX 1  to RX 5  is also a plurality of pulse rows. 
       FIGS. 3A and 3B  are views for describing the touch panel-integrated display device of the related art. 
       FIG. 3A  is a block diagram that shows a schematic configuration of the touch panel-integrated display device of the related art, and  FIG. 3B  is a view that shows a cross-sectional structure of the touch panel-integrated display device of the related art. 
     In the touch panel-integrated display device shown in  FIGS. 3A and 3B , as shown in  FIG. 3B , an electrostatic capacity type touch panel  301  is formed inside the display panel (herein, the liquid crystal display panel)  101 . Other configurations are the same as those of  FIG. 1A , and the repeated detailed description thereof will be omitted. 
       FIGS. 4A and 4B  are views for describing the touch panel  301  shown in  FIGS. 3A and 3B ,  FIG. 4A  is a view that shows an electrode pattern of the touch panel  301  shown in  FIGS. 3A and 3B , and  FIG. 4B  is a cross-sectional view that shows a cross-sectional structure along a cut line A-B of  FIG. 4A . 
     As shown in  FIG. 4A , the touch panel  301  shown in  FIGS. 3A and 3B  has the X electrode  201  and the Y electrode  202  for detecting the capacity. Herein, for example, although the five X electrodes  201  and the seven Y electrodes  202  are shown, the number of the electrodes is not limited thereto. 
     In  FIG. 4B , reference numeral  211  is a first substrate, reference numeral  212  is a second substrate, reference numeral  213  is a lower polarizing plate, reference numeral  214  is an upper polarizing plate, reference numeral  215  is a liquid crystal layer, and reference numeral  216  is a seal material. As shown in  FIG. 4B , the X electrode  201  and the Y electrode  202  are formed on the different parts of the structural member of the liquid crystal display panel. In addition, it is preferable that the first substrate  211  and the second substrate  212  have high optical transmittance. 
     Furthermore, generally, in an IPS type liquid crystal display panel, on the surface of the liquid crystal layer side of the first substrate  211 , from the first substrate  211  toward the liquid crystal layer  215 , a scanning line (also referred to as a gate line), an interlayer insulating film, a picture line (also referred to as a source line or a drain line), a thin film transistor (TFT), a pixel electrode, an interlayer insulating film, a counter electrode (also referred to as a common electrode), and an oriented film are sequentially formed. However,  FIG. 4B  does not show these components. 
     Furthermore, on the liquid crystal layer side of the second substrate  212 , from the second substrate  212  toward the liquid crystal layer  215 , an optical shielding film, color filters of red, green and blue, a flattening film, and an oriented film are sequentially formed. However,  FIG. 4B  does not show these components. 
     In the structure of  FIG. 4B , a back electrode formed on a surface opposite to the liquid crystal layer of the second substrate also serves as the X electrode  201 , and the counter electrode Y also serves as the Y electrode  202 . 
       FIGS. 5A, 5B and 5C  are views that show a detection principle of the touch panel-integrated display device having the structure shown in  FIGS. 4A and 4B . 
       FIG. 5A  is a view that shows a state where the touch operation is not performed,  FIG. 5B  is a view that shows a state where a finger  502  approaches the touch panel  106 , and  FIG. 5C  is a graph that shows a change of the detected signal. 
     As shown in  FIGS. 5A, 5B and 5C , a voltage source  504  is connected to any one electrode (herein, the Y electrode  202 ) of the X electrode  201  and the Y electrode  202 , the pulse (the drive signal) is input from the voltage source  504 , and the transient current accompanied with the input pulse from the voltage source  504  is detected in the detection circuits ( 505  and  506 ) via the other electrode (herein, the X electrode  201 ) that performs the capacity coupling. As shown in  FIG. 5A , the capacity coupling forms a line  501  of electric force between the X electrode and the Y electrode. 
     As shown in  FIG. 5B , when the finger  502  approaches the touch panel  106 , the line  501  of electric force is cut off. Thereby, the transient current is reduced. 
     As shown in  FIG. 5C , when the finger  502  or the like comes into closely contact with, the detection signal level detected in the detection circuits ( 505  and  506 ) is changed from a detection signal level  507  before the contact shown in  FIG. 5A  to a detection signal level  508  after the contact shown in  FIG. 5B . A difference between the detection signal level  507  and the detection signal level  508  is detection sensitivity. 
     In addition, as shown in B of  FIG. 2C , since the detection signal detected by each X electrode  201  is a plurality of pulse rows, the detection circuits ( 505  and  506 ) accumulate the detection signals of the plurality of pulse rows. Specifically, the detection circuits integrate the detection signals by the integration circuit to detect the signals of the detection signal level  507  and the detection signal level  508 . 
     Hereinafter, in the touch panel-integrated display device, a type (a mutual detection) of performing the high-precision coordinate detection, by the use of the change of the electrostatic capacity between the counter electrode (the Y electrode  202  of  FIGS. 4A and 4B ) and the detection electrode for sensor (the X electrode  201  of  FIGS. 4A and 4B ) by the influence of a finger of a user will be described. 
       FIGS. 6A and 6B  are views that describe the mutual detection in the touch panel-integrated display device. 
     As mentioned above, in the touch panel-integrated display device, the counter electrode (the Y electrode  202  of  FIGS. 4A and 4B ) and the detection electrode for sensor (the X electrode  201  of  FIGS. 4A and 4B ) are provided. 
     A mutual capacity  601  is formed between the electrodes. Herein, only one detection electrode for sensor (Rx_n; the X electrode  201  of  FIGS. 4A and 4B ) is noticed. Furthermore, six (Tx_ 1  to  6 ) counter electrodes (the Y electrodes  202  of  FIGS. 4A and 4B ) are provided. 
     The counter electrode (the Y electrode  202  of  FIGS. 4A and 4B ) has an earth capacity  601 . Herein, since the earth capacity of the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) has the electrode structure described in  FIGS. 4A and 4B , substantial mutual capacity  601  is obtained. 
     In the touch panel control unit  108 , a voltage control unit having a pair of switching elements of S 1  and S 2  is provided with respect to each counter electrode (the Y electrode  202  of  FIGS. 4A and 4B ). Furthermore, herein, the voltage to be controlled is set to two voltage levels of Vtxh and Vtxl. 
     Furthermore, the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) is connected to the detection circuit unit via a pair of switching elements of S 3  and S 4 . In addition, in  FIGS. 6A and 6B , the detection circuit unit is constituted by the integration circuit. Furthermore, in  FIGS. 6A and 6B , the voltage level of the reference voltage of the integration circuit is shown by Vref, and the voltage level of the output voltage of the integration circuit is shown by Vo. 
     Hereinafter, the control of the mutual detection will be described based on the circuit configuration shown in  FIG. 6A . 
     The basic operation of the mutual detection includes a reset period and a detection period. The detection is repeatedly performed in the unit of the basic operation, and the counter electrodes becoming the target (the Y electrode  202  of  FIG. 4 ) are sequentially changed.  FIGS. 6A and 6B  show a case where the counter electrode of Tx_ 1  in the counter electrode (the Y electrode  202  of  FIGS. 4A and 4B ) is a target. 
     The reset period is a period that resets the electric potential of the counter electrode of Tx_ 1 . At this period, since the switching element (S 4 ) and the switching element (S 2 ) are connected to each other, the mutual capacity  601  is set to a state of being charged with the voltage of (Vref−Vtxl). In addition, in  FIG. 6B , the voltage of the Vtxl is shown as 0 V. 
     Next, the switching element (S 4 ) and the switching element (S 2 ) enter the open state together, and are shifted to the detection period. 
     In the detection period, first, the switching element (S 3 ) is connected, and the input to the integration circuit is possible. After that, the switching element (S 1 ) is connected, and the electric potential of the counter electrode of Tx_ 1  transits from the voltage of Vtxl to the voltage of Vtxh. At this time, the electric current flows via the mutual capacity  601 . Since the electric current is integrated by the integration circuit, the output voltage (Vo) of the integration circuit changes. 
     Furthermore, since the electric current is proportional to the magnitude of the mutual capacity  601 , when there is a conductor such as a finger, the capacity thereof drops, and thus the electric current also drops. Thereby, since the output voltage (Vo) of the integration circuit also changes, the detection thereof is possible. 
     Thereafter, after the switching element (S 3 ) is opened and the integration circuit is detached, the switching element (S 4 ) is connected. 
     Thereafter, the switching element (S 2 ) is connected. After that, this operation is repeated. 
     Hereinafter, in the touch panel-integrated display device, a type (hereinafter referred to as a self detection) of detecting whether or not the measurement target approaches even if there is no coordinate information, by the use of the change of the earth capacity of the detection electrode for sensor (the X electrode  201  of  FIGS. 4A and 4B ) by the influence of a finger of a user will be described. 
       FIGS. 7A and 7B  are views that describe the control of the self detection of the present example in the touch panel-integrated display device. Hereinafter, the control of the self detection will be described based on the circuit configuration shown in  FIG. 7A . 
     The self detection period includes the respective periods of the reset period, the charge period, and the detection period. Herein, the control of the switching element (S 1 ) and the switching element (S 2 ) is concurrently performed in the entire counter electrodes (the Y electrode  202  of  FIGS. 4A and 4B ; Tx_ 1  to  6 ). Furthermore, herein, only one detection electrode for sensor (Rx_n; the X electrode  201  of  FIGS. 4A and 4B ) will be noticed. 
     In the reset period, since the switching element (S 2 ) and the switching element (S 4 ) are connected to each other and the mutual capacity  601  is reset, the mutual capacity  601  enters the state of being charged with the voltage of (Vref−Vtxl). 
     Thereby, the electric potential of the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) becomes the voltage of Vref. 
     Next, the switching element (S 2 ) and the switching element (S 4 ) are opened together, and transits to the charge period. At this time, the switching element (S 3 ) and the switching element (S 4 ) enter the open state together, then the switching element (S 1 ) is connected, and the electric potential of the entire counter electrode (Tx_ 1  to  6 ) becomes the voltage of Vtxh. 
     In the reset period, since the mutual capacity  601  is charged with the voltage of (Vref−Vtxl), the electric potential of the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) becomes the voltage of (Vref−Vtxl+Vtxh) at the charge period. In addition, in  FIG. 7B , the voltage of Vtxl is shown as 0 V. 
     When there is a finger or the like near the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ), the change of the electric potential of the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) also concurrently charges the electrostatic capacity formed between the finger and the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ). 
     After the charge period, the period is shifted to the detection period. At this time, the switching element (S 1 ) and the switching element (S 3 ) are connected to each other, and the switching element (S 2 ) and the switching element (S 4 ) are opened. When the switching element (S 3 ) is connected, the capacity between the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) and all the counter electrodes (Tx_ 1  to  6 ), that is, the capacity corresponding to the electric potential difference of (Vtxh−Vtxl) in the electric charge charged in the mutual capacity  601 , and the electric charge charged in the electrostatic capacity between the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) and a finger or the like is moved to the integration circuit. The output voltage (Vo) of the integration circuit changes due to the electric charge. 
     Herein, when there is no finger or the like near the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ), since there is no electric charge charged in the electrostatic capacity between the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) and a finger or the like, the amount of electric charge moved to the integration circuit is small, and thus the output change of the integration circuit becomes smaller. 
     Thereby, the self detection becomes possible. Thereafter, this operation is repeated. 
       FIGS. 8A and 8B  are views that describe the detection state of the self detection of the present example in the touch panel-integrated display device. 
       FIG. 8A  shows a case where a finger or the like does not approach in the detection period described in  FIGS. 7A and 7B . The amount of electric charge, which is read from the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ), is an electric charge (Q 1 ) that is charged due to the structure of the mutual capacity  601  or the like. 
       FIG. 8B  shows a case where a finger or the like approaches in the detection period described in  FIGS. 7A and 7B . The amount of electric charge, which is read from the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ), is a sum (Q 1 +Q 2 ) of the electric charge (Q 1 ) charged due to the structure of the mutual capacity  601  or the like and an electric charge (Q 2 ) charged between the detection electrode for sensor of Rx_n (the X electrode  201  of  FIGS. 4A and 4B ) and a finger or the like. Thereby, it is possible to detect the present or absence of a detection object (for example, a finger) by the voltage difference of the output voltage of the integration circuit. 
     In addition, since the integration circuit is provided for each detection electrode for sensor (the X electrode  201  of  FIGS. 4A and 4B ), in the self detection period, the output voltage (Vo) is output from the integration circuit provided in each detection electrode for sensor (the X electrode  201  of  FIGS. 4A and 4B ), respectively. 
     In this case, for example, as the determination of the present or absence of the detection object (for example, a finger), when the output voltage (Vo) that is output from one integration circuit of the plurality of integration circuits is a predetermined value or more, it may be determined that there is a detection object, when the output voltage (Vo), which is output from the integration circuit more than half of the plurality of integration circuits, is a predetermined value or more, it may be determined that there is a detection object, or when the output voltages (Vo), which are output from all the integration circuits, are predetermined values or more, it may be determined that there is adetection object. 
     Hereinafter, a more specific configuration of the liquid crystal touch panel-integrated display device of the example of the invention will be described. 
       FIG. 9  is a perspective view that shows a more specific configuration of the liquid crystal touch panel-integrated display device of the example of the invention. A liquid crystal display device  100  shown in  FIG. 9  includes a liquid crystal display panel  1 , a drive circuit  5 , a flexible substrate  70 , a front panel  40 , a storage case (not shown), and a backlight (not shown). 
     The liquid crystal display panel  1  has a TFT substrate  2  and a color filter substrate  3 . The TFT substrate  2  and the color filter substrate  3  are stacked each other at a predetermined interval, both substrates are bonded to each other by a sealing material (not shown) provided near a peripheral portion between both substrates, a liquid crystal composition is enclosed and sealed inside the sealing material, and a polarizing plate is stuck to the outside of both substrates. 
     The TFT substrate  2  is provided with a counter electrode  21 , and a counter electrode signal line  22  connected to the counter electrode  21  from the drive circuit  5 . The counter electrode signal can be transmitted from the drive circuit  5  to the counter electrode  21  via the counter electrode signal line  22 . The color filter substrate  3  is provided with the detection electrode  31  (the X electrode  201  of  FIGS. 4A and 4B ), and the detection electrode  31  is connected to a flexible substrate  75  using a connection portion  77 . The flexible substrate  75  is connected to the flexible substrate  70  using a connector  80 . The detection signal from the detection electrode  31  is transmitted to the drive circuit  5  via the flexible substrate  75 , the connector  80 , and the flexible substrate  70 . 
     In addition, the liquid crystal display panel  1  has a display unit including a plurality of pixels in a matrix form. The counter electrode  21  is placed to face the pixel electrode in the pixel. By applying the voltage between both electrodes, the orientations of the liquid crystal molecules change. Along with the change of the orientation of the liquid crystal molecules, the transmittance of light changes, and the image is displayed. 
     Next, the detection electrode  31  and the counter electrode  21  of the liquid crystal display device  100  shown in  FIG. 9  will be described using  FIG. 10 . 
     As mentioned above, although the counter electrode  21  is provided on the TFT substrate  2 , the counter electrodes  21  of plural lines (for example, about twenty) are commonly connected to both ends, and are connected to the counter electrode signal line  22 . The counter electrode signal is supplied to the fascicular counter electrode  21  from the drive circuit  5 . 
     In the liquid crystal display device  100  shown in  FIG. 9 , the fascicular counter electrode  21  also serves as the Y electrode  202  shown in  FIGS. 4A and 4B , and forms the scanning electrode of the invention. Furthermore, the detection electrode  31  corresponds to the X electrode  201  of  FIGS. 4A and 4B , and forms the detection electrode of the invention. 
     Thus, the counter electrode signal includes the counter voltage used for the image display, and the drive signal (the input pulse voltage of  FIGS. 7A and 7B ) used for the detection of the touch position. When the drive signal is applied to the counter electrode  21 , the detection signal is generated in the detection electrode  31  that is placed at a fixed interval with the counter electrode  21  to form the capacity. The detection signal is taken out to the outside via the terminal  36  for the detection electrode. 
     In addition, dummy electrodes  33  are formed on both sides of the detection electrode  31 . The detection electrode  31  forms the T-shaped terminal  36  for the detection electrode of expanded toward the dummy electrode  33  side in one end portion. Furthermore, the TFT substrate  2  is also formed with various wirings, terminals or the like such as the input terminal  25  for the drive circuit, in addition to the counter electrode signal line  22 . 
       FIG. 11  shows an enlarged schematic cross-sectional view of a part of the cross section of the display unit in the liquid crystal display device  100  shown in  FIG. 9 . 
     As shown in  FIG. 11 , a pixel unit  200  is provided on the TFT substrate  2 , and the counter electrode  21  is used for the image display as a part of the pixel. Furthermore, the liquid crystal composition  4  is interposed between the TFT substrate  2  and the color filter substrate  3 . The detection electrode  31  provided in the color filter substrate  3  and the counter electrode  21  provided in the TFT substrate form the capacity, and when the drive signal is applied to the counter electrode  21 , the voltage of the detection electrode  31  changes. 
     At this time, as shown in  FIG. 11 , when a conductor such as a finger approaches or comes into contact therewith via the front panel  40 , the capacity changes, and the voltage generated in the detection electrode  31  changes compared to a case where there is no approach and contact. 
     In this manner, by detecting the change of the capacity generated between the counter electrode  21  formed on the liquid crystal display panel  1  and the detection electrode  31 , the liquid crystal display panel  1  is able to include the function of the touch panel. 
     As described above, in the present embodiment, in the touch panel-integrated display device, the detection circuit used for the mutual detection can also be used for the self detection, and thus it is possible to realize the miniaturization and the cost reduction of the control IC. 
     As mentioned above, although the invention made by the inventors has been specifically described based on the above-mentioned example, the invention is not limited to the above-mentioned example, and, of course, can be changed within the scope that does not depart from the gist thereof in various forms. 
     While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claim cover all such modifications as fall within the true spirit and scope of the invention.