Patent Publication Number: US-10310664-B2

Title: Display device with touch detection function

Description:
RELATED APPLICATION DATA 
     This application is a continuation of Ser. No. 15/381,660 filed Dec. 16, 2016, which is a continuation of U.S. patent application Ser. No. 14/684,571 filed Apr. 13, 2015, now U.S. Pat. No. 9,557,842 issued Jan. 31, 2017, which is a continuation of U.S. patent application Ser. No. 13/211,441 filed Aug. 17, 2011, now U.S. Pat. No. 9,030,420 issued May 12, 2015, the entireties of which are incorporated herein by reference to the extent permitted by law. The present application claims the benefit of priority to Japanese Patent Application No. JP 2010-187175 filed on Aug. 24, 2010 in the Japan Patent Office, the entirety of which is incorporated by reference herein to the extent permitted by law. 
    
    
     BACKGROUND 
     This disclosure relates to a touch panel which enables a user to input information by bringing a user&#39;s finger etc. into contact therewith or bringing the same in proximity thereto. In particular, the disclosure relates to a display device with a touch detection function, of a type which detects the contact or the proximity based on a change in an electrostatic capacitance. 
     In recent years, attention has been drawn to a display device in which a contact detector, generally referred to as a touch panel, is mounted on a display such as a liquid crystal display, and which allows the display to display various button images etc. to thereby make it possible to input information instead of providing typical mechanical buttons. There are a number of types of touch panels, including such as an optical type and a resistance type. In devices such as a portable handheld terminal, in particular, there are high expectations for a touch panel of an electrostatic capacitance type. The electrostatic capacitance touch panel has a relatively simple configuration, and is capable of reducing power consumption. 
     Japanese Unexamined Patent Application Publication No. 2009-244958 (JP2009-244958A) discloses a display device with a touch detection function, in which the electrostatic capacitance touch panel is incorporated in the liquid crystal display device. The display device with the touch detection function disclosed therein is provided with a pixel electrode used for displaying an image, a touch detection electrode used for detecting a touch, and a drive electrode (a common electrode) shared by the pixel electrode and the touch detection electrode. JP2009-244958A discloses an embodiment where a plurality of drive electrodes, extending in a horizontal direction and divided in a perpendicular direction, are used (FIG. 5 of JP2009-244958A). 
     SUMMARY 
     The inventor/the inventors has/have found that when the number of division of electrodes is excessive in a configuration where a plurality of drive electrodes are used as discussed above, a magnitude and the number of wirings of a circuit used for the drive electrodes, especially the one which is disposed at a frame region outside an effective display region, within a substrate on which electrodes are formed are increased. In order to keep down the circuit magnitude and the number of wirings, it may be contemplated to drive a number of divided drive electrodes in a bundle or collectively. Also, in such case, it may be contemplated to form a width in a perpendicular direction of a single drive electrode to have a size corresponding to a plurality of pixels. However, a slit-like clearance is generated in a horizontal direction between the adjacent drive electrodes when the configuration is utilized which uses the plurality of drive electrodes. Thus, states of orientation of liquid crystal molecules are disturbed due to a structural difference between a portion where the slit-like clearance is formed and a portion where the drive electrode is formed. As a result, a portion corresponding to the slit-like clearance may be seen as a streak-like display defect. 
     It is desirable to provide a display device with a touch detection function, capable of keeping down a circuit magnitude and the number of wirings and suppressing deterioration in display quality while using a plurality of drive electrodes. 
     A display device with a touch detection function according to an embodiment of the technology includes: a plurality of drive electrodes extending in a first direction and arranged side-by-side in a second direction with an inter-electrode slit in between, each of the drive electrodes being supplied with a drive signal; a display section having a plurality of pixel electrodes arranged in matrix in the first and second directions to face the drive electrodes, application of the drive signal to each of the drive electrodes and application of an image signal to each of the pixel electrodes allowing image display; and a touch detection electrode allowing an electrostatic capacitance to be formed between the touch detection electrode and the drive electrodes, to output a detection signal in response to the drive signal applied to the drive electrodes. Each of the drive electrodes has a width in the second direction corresponding to a size of the two or more pixel electrodes, and has one or more inner-electrode slits extending in the first direction. 
     A display device according to another embodiment of the technology includes: a display section having a plurality of pixel electrodes; and a plurality of drive electrodes extending in a first direction and arranged side-by-side in a second direction. Each of the drive electrodes has a width in the second direction corresponding to a size of the two or more pixel electrodes, and has one or more slits extending in the first direction. 
     As used herein, the term “touch” refers not only to a contact of an object such as a finger of a user and a member including a pen, but also to an indirect contact or “proximity” of such an object. 
     In the display device with the touch detection function and the display device according to the embodiments of the technology, each of the drive electrodes has the width corresponding to the size of the two or more pixel electrodes. Thus, a circuit magnitude and the number of wirings used for the drive electrodes are kept down. Also, each of the drive electrodes has the one or more inner-electrode slits, and the inter-electrode slit corresponding to the inner-electrode slit is provided between the adjacent drive electrodes. Thus, a structural difference between a portion where the drive electrode is formed and a portion between the adjacent drive electrodes is reduced. 
     According to the display device with the touch detection function and the display device of the embodiments of the technology, each of the drive electrodes has the one or more inner-electrode slits, and the inter-electrode slit corresponding to the inner-electrode slit is provided between the adjacent drive electrodes. This makes it possible to reduce a structural difference between a portion where the drive electrode is formed and a portion between the adjacent drive electrodes. Hence, it is possible to uniformize states of orientation of liquid crystal molecules throughout the entire display region in an embodiment where any one of the display device with the touch detection function and the display device is applied to a liquid crystal device. Also, each of the drive electrodes has the width corresponding to the size of the two or more pixel electrodes, making it possible to keep down a circuit magnitude and the number of wirings used for the drive electrodes. Therefore, it is possible to keep down the circuit magnitude and the number of wirings and to suppress deterioration in display quality while using the plurality of drive electrodes. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the technology as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the specification, serve to explain the principles of the technology. 
         FIG. 1  is an explanatory diagram for describing a basic principle of a touch detection scheme in a display device with a touch detection function according to embodiments of the technology, and illustrates a case where an external proximity object such as a finger is not in a contact state nor is in a proximity state. 
         FIG. 2  is an explanatory diagram for describing the basic principle of the touch detection scheme in the display device with the touch detection function according to the embodiments, and illustrates a case where the finger is in the contact state or is in the proximity state. 
         FIG. 3  is an explanatory diagram for describing the basic principle of the touch detection scheme in the display device with the touch detection function according to the embodiments, and illustrates an example of a waveform of a drive signal and an example of a waveform of a detection signal. 
         FIG. 4  is a block diagram illustrating an exemplary configuration of a display device with a touch detection function according to the embodiments of the technology. 
         FIG. 5  is a cross-sectional view illustrating a schematic cross-sectional configuration of a touch detection function display unit in the display device with the touch detection function illustrated in  FIG. 4 . 
         FIG. 6  is a circuit diagram illustrating a pixel array of the touch detection function display unit illustrated in  FIG. 5 . 
         FIG. 7  is a perspective view illustrating an exemplary configuration of drive electrodes and that of touch detection electrodes of the touch detection function display unit illustrated in  FIG. 5 . 
         FIGS. 8A to 8C  describe a scanning method of the drive electrodes in the touch detection function display unit illustrated in  FIG. 5 . 
         FIG. 9  is a plan view illustrating a detailed exemplary configuration of the drive electrodes in the touch detection function display unit illustrated in  FIG. 5 . 
       Part (A) of  FIG. 10  is a plan view illustrating a connection structure of the drive electrodes and a pixel substrate in the touch detection function display unit illustrated in  FIG. 5 , and part (B) of  FIG. 10  is a cross-sectional view illustrating a main part of a connection portion of the drive electrode and the pixel substrate. 
         FIG. 11  is a plan view illustrating a correspondence relationship between the drive electrodes and pixel electrodes in the touch detection function display unit illustrated in  FIG. 5 . 
         FIG. 12  is a characteristic diagram illustrating a human luminosity factor. 
         FIG. 13  is a plan view for describing a specific design example of the drive electrodes in the touch detection function display unit illustrated in  FIG. 5 . 
         FIG. 14  describes a measurement environment of a specific example. 
         FIG. 15  describes a result of measurement on recognition of a slit when a pitch of the slit of a drive electrode is varied in the touch detection function display unit illustrated in  FIG. 5 . 
         FIG. 16  is a cross-sectional view illustrating a schematic cross-sectional configuration of a display device with a touch detection function according to a second embodiment of the technology. 
         FIGS. 17A and 17B  are enlarged perspective views illustrating a main part of the display device with the touch detection function illustrated in  FIG. 16 . 
         FIGS. 18A and 18B  are cross-sectional views for describing an operation of the display device with the touch detection function illustrated in  FIG. 16 . 
         FIG. 19  is a plan view illustrating a configuration of drive electrodes in a display device with a touch detection function according to a third embodiment of the technology. 
         FIG. 20  is a cross-sectional view illustrating a cross-sectional configuration of a main part of a pixel substrate in the display device with the touch detection function illustrated in  FIG. 19 . 
         FIG. 21  is a plan view illustrating a plan configuration of the main part of the pixel substrate in the display device with the touch detection function illustrated in  FIG. 20 . 
         FIG. 22  describes an action of a drive electrode in the display device with the touch detection function illustrated in  FIG. 20 . 
         FIG. 23  is a plan view illustrating a plan configuration of a pixel substrate according to a comparative example with respect to the pixel substrate illustrated in  FIG. 21 . 
         FIG. 24  describes a problem of a noise generated when the configuration according to the comparative example illustrated in  FIG. 23  is employed. 
         FIG. 25  is a perspective view schematically illustrating an external configuration of a first application example to which the display device with the touch detection function according to any one of the embodiments is applied. 
         FIGS. 26A and 26B  are perspective views illustrating an external configuration of a second application example as viewed from front and behind, respectively. 
         FIG. 27  is a perspective view illustrating an external configuration of a third application example. 
         FIG. 28  is a perspective view illustrating an external configuration of a fourth application example. 
         FIG. 29A  is a front view in an open state,  FIG. 29B  is a side view in the open state,  FIG. 29C  is a front view in a closed state,  FIG. 29D  is a left side view,  FIG. 29E  is a right side view,  FIG. 29F  is a top view, and  FIG. 29G  is a bottom view, each illustrating an external configuration of a fifth application example. 
     
    
    
     DETAILED DESCRIPTION 
     In the following, some embodiments of the technology will be described in detail with reference to the accompanying drawings. 
     (Basic Principle of Electrostatic Capacitance Type Touch Detection) 
     First, with reference to  FIGS. 1 to 3 , a basic principle of a touch detection in a display device with a touch detection function according to embodiments will be described. This touch detection scheme is embodied as an electrostatic capacitance type touch sensor. For example, as illustrated in (A) of  FIG. 1 , a pair of electrodes (a drive electrode E 1  and a detection electrode E 2 ), which are disposed to face each other with a dielectric D interposed in between, are used to configure a capacitor element C 1 . This configuration is representable as an equivalent circuit illustrated in (B) of  FIG. 1 . The capacitor element C 1  is configured by the drive electrode E 1 , the detection electrode E 2 , and the dielectric D. The capacitor element C 1  has a first end connected to an AC signal source (a drive signal source) S, and a second end P grounded through a resistor R and connected to a voltage detector (a detection circuit) DET. When an AC rectangular wave Sg ((B) of  FIG. 3 ) having a predetermined frequency (for example, approximately several kHz to ten-odd kHz) is applied from the AC signal source S to the drive electrode E 1  (the first end of the capacitor element C 1 ), an output waveform (a detection signal Vdet) illustrated in (A) of  FIG. 3  appears in the detection electrode E 2  (the second end P of the capacitor element C 1 ). This AC rectangular wave Sg is equivalent to a drive signal Vcom, which will be described later. 
     As illustrated in  FIG. 1 , in a case where an external proximity object (such as a finger in the exemplary embodiments, although a member such as a pen may be used) is not in a contact state nor is in a proximity state, a current I 0  corresponding to a capacitance value of the capacitor element C 1  flows in accordance with charge/discharge performed on the capacitor element C 1 . An electric potential waveform of the second end P in the capacitor element C 1  at this time is, for example, as illustrated by a waveform V 0  in (A) of  FIG. 3 , which is detected by the voltage detector DET. 
     On the other hand, in a case where the finger is in the contact state or is in the proximity state, a capacitor element C 2  formed by the finger is added in series to the capacitor element C 1 , as illustrated in  FIG. 2 . In this state, when charge/discharge is performed on the capacitor elements C 1  and C 2 , currents I 1  and I 2  flow, respectively. The electric potential waveform of the second end P in the capacitor element C 1  at this time is, for example, as illustrated by a waveform V 1  in (A) of  FIG. 3 , which is detected by the voltage detector DET. Here, an electric potential at the second end P is a divided electric potential determined by values of the currents I 1  and I 2  flowing through the capacitor elements C 1  and C 2 , respectively. Hence, the waveform V 1  is smaller in value than the waveform V 0  derived from the non-contact state or from the non-proximity state. The voltage detector DET compares the detected voltage with a predetermined threshold voltage Vth. The voltage detector DET determines that the finger is in the non-contact state or is in the non-proximity state when the detected voltage is equal to or larger than the threshold voltage Vth, whereas, the detector DET determines that the finger is in the contact state or is in the proximity state when the detected voltage is smaller than the threshold voltage Vth, thereby making it possible to perform the touch detection. 
     First Embodiment 
     Configuration Example 
     (Overall Configuration) 
       FIG. 4  illustrates an exemplary configuration of a display device with a touch detection function  40  according to a first embodiment of the technology. The display device with the touch detection function according to this embodiment is a device of a so-called “in-cell” type, in which a liquid crystal display element is used as a display element, and in which a liquid crystal display unit, configured by the liquid crystal display element, and a touch sensor of an electrostatic capacitance type are integrated. 
     The display device with the touch detection function  40  is provided with a Vcom generating section  41 , a drive control circuit  42 , a drive electrode driver  43 , a display unit with a touch detection function (hereinafter simply referred to as a “touch detection function display unit”)  44 , a gate driver  45 , a source driver  46 , a multiplexer  47 , a detection circuit  48 , and a resistor R. 
     The Vcom generating section  41  serves as a circuit by which the drive signal Vcom used in the touch detection function display unit  44  is generated. The drive signal Vcom may have a rectangular wave, for example. 
     The drive control circuit  42  serves as a circuit which, when supplying a later-described plurality of drive electrodes in the touch detection function display unit  44  with the drive signal Vcom supplied from the Vcom generating section  41 , selects the drive electrodes to control the same. In controlling the drive electrodes, the drive control circuit  42  controls a movement of scanning of the drive electrodes subjected to application of the drive signal Vcom, for example. 
     The drive electrode driver  43  serves as a circuit which supplies, based on a control signal supplied from the drive control circuit  42 , the later-described plurality of drive electrodes in the touch detection function display unit  44  with the drive signal Vcom supplied from the Vcom generating section  41 . 
     The touch detection function display unit  44  includes a touch sensor  441  and a liquid crystal display unit  442  (a display section). The touch sensor  441  operates and outputs, based on the basic principle of the electrostatic capacitance type touch detection described above, the detection signal Vdet. The detection signal Vdet includes a signal component derived from a touch operation. 
     The gate driver  45  serves as a circuit which supplies the liquid crystal display unit  442  with a signal by which a horizontal pixel line subjected to displaying is selected. The source driver  46  serves as a circuit which supplies the liquid crystal display unit  442  with an image signal. The multiplexer  47  serves as a circuit which, when obtaining in order the detection signal Vdet from the later-described plurality of touch detection electrodes of the touch sensor  441 , switches the sources from which the detection signal Vdet is to be obtained. 
     The detection circuit  48  detects, based on the detection signal Vdet switched over in the multiplexer  47 , a presence or absence of the touch performed on the touch sensor  441 , and further obtains a coordinate thereof on the touch panel, for example. The detection circuit  48  includes an analog LPF (Low Pass Filter) section  51 , an A/D (Analog-to-Digital) converting section  52 , a signal processing section  53 , and a coordinate extracting section  54 . The analog LPF section  51  serves as a low-pass analog filter which removes a high-frequency component from detection signal Vdet, and outputs the detection signal Vdet subjected to the high-frequency component removal. The analog LPF section  51  may remove a folding noise generated in the A/D converting section  52 , for example. The A/D converting section  52  serves as a circuit which converts the analog signal supplied from the analog LPF section  51  into a digital signal. The signal processing section  53  serves as a logic circuit which, based on an output signal from the A/D converting section  52 , detects the presence or absence of the touch performed on the touch sensor  441 . The coordinate extracting section  54  serves as a logic circuit which obtains a touch panel coordinate at which the touch detection has been performed in the signal processing section  53 . 
     The circuits described above are controlled by an unillustrated timing controlling section. 
     (Exemplary Configuration of Touch Detection Function Display Unit  44 ) 
       FIG. 5  illustrates an example of a cross-sectional configuration of a main part of the touch detection function display unit  44 . The touch detection function display unit  44  includes a pixel substrate  2 , an opposed substrate  3  disposed to face the pixel substrate  2 , and a liquid crystal layer  6  inserted between the pixel substrate  2  and the opposed substrate  3 . 
     The pixel substrate  2  includes a TFT (Thin-Film Transistor) substrate  21  serving as a circuit board, and a plurality of pixel electrodes  22  disposed in matrix in a first direction (a horizontal direction) and a second direction (a perpendicular direction) on the TFT substrate  21 . As will be described later with reference to  FIG. 6 , the TFT substrate  21  is formed with TFTs for respective pixels, and wirings such as source lines (image signal wirings) for supplying the image signal to the respective pixel electrodes  22 , gate lines for driving the respective TFTs, and drive signal wirings for supplying the drive signal to the later-described drive electrodes  33 . Also, the pixel substrate  2  may be formed to include a part or all of the circuits illustrated in  FIG. 4 . 
     The opposed substrate  3  includes a glass substrate  31 , a color filter  32  formed on a first surface of the glass substrate  31 , and the drive electrodes  33  formed on the color filter  32 . The color filter  32  has a configuration in which, for example, color filter layers of three colors of red (R), green (G), and blue (B) are periodically aligned. Here, a set of three colors of R, G and B is assigned to each display pixel, although the number of colors and the types of colors are not limited thereto. The drive electrode  33  serves as a common drive electrode of the liquid crystal display unit  442 , and also serves as the drive electrode of the touch sensor  441 . The drive electrode  33  is coupled to the TFT substrate  21  by a contact conductive pillar  7 . The drive signal Vcom having an AC rectangular waveform is applied from the TFT substrate  21  through the contact conductive pillar  7  to the drive electrode  33 . The drive signal Vcom, together with a pixel voltage applied to the pixel electrodes  22 , defines a display voltage of each of the pixels, and may also be referred to as a common drive signal. Further, the drive signal Vcom is used also as the drive signal of the touch sensor  441 . 
     A second surface of the glass substrate  31  is formed with the touch detection electrodes  34  serving as detection electrodes of the touch sensor  441 . Also, a polarizing plate  35  is disposed on the touch detection electrodes  34 . 
     The liquid crystal layer  6  modulates light passing therethrough in response to a state of an electric field, and is configured of a liquid crystal in any of various modes such as a TN (Twisted Nematic) mode and an ECB (Electrically-Controlled Birefringence) mode. 
     Alignment films are respectively disposed between the liquid crystal layer  6  and the pixel substrate  2  and between the liquid crystal layer  6  and the opposed substrate  3 , and a light-incident side polarizing plate is disposed below the pixel substrate  2 , illustrations of which are omitted in the drawings. 
       FIG. 6  illustrates an example of a pixel configuration in the liquid crystal display unit  442 . The liquid crystal display unit  442  includes the plurality of display pixels  20  which are arranged in matrix. The display pixel  20  includes a TFT element Tr and a liquid crystal element LC. 
     The display pixel  20  is connected with a source line  25 , a gate line  26 , and the drive electrode  33 . The source line  25  serves as a signal line for supplying the image signal to each of the display pixels  20 , and is connected to the source driver  46  illustrated in  FIG. 4 . The gate line  26  serves as a signal line (a scanning line) for supplying the signal by which the display pixels  20  subjected to displaying are selected, and is connected to the gate driver  45  illustrated in  FIG. 4 . In this embodiment, each of the gate lines  26  is connected to all of the display pixels  20  which are disposed horizontally. In other words, in the liquid crystal display unit  442 , the displaying is performed one display horizontal line at a time based on the control signal from each of the gate lines  26 . 
     The drive electrode  33  serves as an electrode for applying the drive signal used for driving the liquid crystals, and is connected to the drive electrode driver  43  illustrated in  FIG. 4 . Each of the drive electrodes  33  is a strip-like electrode that extends in the first direction (the horizontal direction), and is arranged in a side-by-side fashion in the second direction (the perpendicular direction), as will be described later. Further, the respective drive electrodes  33  correspond to the horizontal pixel lines (four horizontal pixel lines in  FIG. 6 ). In other words, in the liquid crystal display unit  442 , the plurality of horizontal pixel lines are driven collectively based on the drive signal of each of the drive electrodes  33 . 
       FIG. 7  is a perspective view illustrating an exemplary configuration with respect to the touch sensor  441  of the drive electrodes  33  and the touch detection electrodes  34  in the opposed substrate  3 . Each of the drive electrodes  33  is a strip-like electrode that extends in the first direction (the horizontal direction), and is arranged in a side-by-side fashion in the second direction (the perpendicular direction). Each of the drive electrodes  33  is sequentially supplied with the drive signal Vcom by the drive electrode driver  43  illustrated in  FIG. 4 , and is thus driven based on the sequential scanning performed in a time-divisional fashion as illustrated in  FIGS. 8A to 8C . On the other hand, each of the touch detection electrodes  34  is configured of a strip-like electrode pattern extending in a direction orthogonal to the extending direction of electrode patterns of the drive electrodes  33 . Each of the electrode patterns of the touch detection electrodes  34  outputs the detection signal Vdet, which is supplied to the detection circuit  48  through the multiplexer  47  illustrated in  FIG. 4 . 
     The electrode patterns which intersect one another by the drive electrode  33  and the touch detection electrode  34  form an electrostatic capacitance at a location at which the drive electrode  33  and the touch detection electrode  34  intersect each other. The drive electrode  33  corresponds to the drive electrode E 1  whereas the touch detection electrode  34  corresponds to the touch detection electrode E 2  in the basic principle of the touch detection described above with reference to  FIGS. 1 and 2 . Hence, the touch sensor  441  can detect the touch in accordance with the basic principle discussed above. Further, the electrode patterns that intersect one another configure the touch sensor  441  having a matrix configuration. Hence, detection of a position at which a contact or proximity of an object has occurred is possible. 
     (Detailed Exemplary Configuration of Drive Electrode  33 ) 
       FIGS. 9 and 11  each illustrate a detailed exemplary configuration of the plurality of drive electrodes  33 . Note that  FIG. 11  is equivalent to illustration in which  FIG. 9  is partially enlarged, although a ratio in  FIG. 11  of a length in the horizontal direction and a length in the perpendicular direction is changed as compared with that of  FIG. 9  for the purpose of easier understanding of an electrode configuration. Also, in  FIG. 9 , a size of the pixel electrode  22  is equivalent to a size of a single pixel or a single sub-pixel. A width W 1  of the single drive electrode  33  has a size corresponding to two or more pixel electrodes  22  (four pixel electrodes  22  in  FIG. 11 ) in the second direction (the perpendicular direction). Each of the drive electrodes  33  has an inner-electrode slit  33 A so provided as to extend in the first direction (the horizontal direction). An inter-electrode slit  33 B that corresponds to the inner-electrode slit  33 A is formed between the two adjacent drive electrodes  33 . Each of the drive electrodes  33  has a length which is larger than that of an effective display region in the display section (the liquid crystal display unit  442  as illustrated in  FIG. 4 ) in the first direction. The inner-electrode slit  33 A is provided at least within the effective display region as illustrated in  FIG. 9 . 
     Each of the drive electrodes  33  is connected to the drive signal wiring formed on the TFT substrate  21  ( FIG. 5 ) through the contact conductive pillar  7  ( FIG. 5 ).  FIG. 10  illustrates an exemplified connection structure utilizing the contact conductive pillar  7  (a contact portion). The contact conductive pillar  7  is provided outside of the effective display region. Part (A) of  FIG. 10  illustrates an example where the contact conductive pillars  7  are provided at positions that are further outside of the inner-electrode slits  33 A provided in the effective display region and that are on either side of the respective drive electrodes  33 . As illustrated in part (B) of  FIG. 10 , the contact conductive pillar  7  has a pillar portion  7 A, and a conductive film  7 B that covers the pillar portion  7 A. Alternatively, a configuration may be employed where the conduction is accomplished by using an anisotropic conductive film (ACF), instead of the configuration utilizing the contact conductive pillar  7  illustrated in part (B) of  FIG. 10 . The anisotropic conductive film is a film that may be obtained by mixing a thermosetting resin with fine metallic particles and forming a thus-obtained resultant into a film. When the anisotropic conductive film is sandwiched between two component parts and is pressurized while applying a heat, the metallic particles dispersed in the film contact one another and thus form a conductive path. 
     Each of the drive electrodes  33  has one or more inner-electrode slits  33 A.  FIGS. 9 and 11  each illustrate an example where each of the drive electrodes  33  includes three inner-electrode slits  33 A, although it is not limited thereto. A spacing in the second direction between the adjacent inner-electrode slits  33 A (when the drive electrode  33  has two or more inner-electrode slits  33 A), and a spacing in the second direction between the inner-electrode slit  33 A and the inter-electrode slit  33 B that are adjacent to each other, are each set to have a size corresponding to the single pixel electrode  22 . Thus, as illustrated in  FIG. 11 , the inner-electrode slit  33 A and the inter-electrode slit  33 B are each located between the two pixel electrodes  22  that are adjacent to each other (or the two adjacent sub pixels). 
     Referring now to  FIGS. 12 and 13 , a specific design example of the drive electrode  33  will be described.  FIG. 12  illustrates a human luminosity factor (a spatial frequency characteristic). When a size such as a width of the inner-electrode slit  33 A and the inter-electrode slit  33 B is increased excessively, orientation states of liquid crystal molecules are varied greatly between a portion which is between the pixels and a portion which is inside of the pixel due to an influence of a lateral electric field to cause a defect. When this becomes prominent, a leakage of light occurs from a portion having the defect at the time of black displaying, reducing a contrast significantly. A width W 2  of the inner-electrode slit  33 A and a width W 3  of the inter-electrode slit  33 B each may be set based on a typical width between pixels such as about 10 micrometers or less, for example, although it is preferable that they be each smaller than the width between the pixels in one embodiment. Also, it is preferable that the width W 2  of the inner-electrode slit  33 A and the width W 3  of the inter-electrode slit  33 B each may be smaller than the source line (the signal line)  25  and the gate line (the scanning line)  26  of the pixels as illustrated in  FIG. 6  in one embodiment. Further, in one embodiment, the following design example is preferable with respect to each element when taking the human luminosity factor into consideration, where a slit spacing (a slit pitch) W 4  is a spacing between the adjacent inner-electrode slits  33 A or a spacing between the inner-electrode slit  33 A and the inter-electrode slit  33 B that are adjacent to each other. 
     Width W 1  of drive electrode  33 : about 2 mm to 10 mm (preferably 5 mm to 10 mm) 
     Width W 2  of the inner-electrode slit  33 A: 10 micrometers or less 
     Width W 3  of the inter-electrode slit  33 B: 10 micrometers or less 
     Slit spacing (slit pitch) W 4 : 500 micrometers or less (integral multiple of pixel pitch) 
       FIG. 15  describes a result of measurement on recognition of the streak-like (slit-like) display defect when the slit pitch of the drive electrode  33  was varied in the touch detection function display unit  44 .  FIG. 14  describes a measurement environment thereof. The measurement was performed for a typical visual environment of the touch detection function display unit  44 , with a surface luminance of 300 cd/m 2  and a distance of about 20 centimeters away from the touch detection function display unit  44 , for example. Referring to  FIG. 15 , the streak-like display defect was observed when the slit pitch W 4  was 600 micrometers or more. The display defect was hardly observed in a streak-like fashion when the slit pitch W 4  was 500 and 400 micrometers, but was observed in the distance of 20 centimeters or less. No streak-like display defect was observed at all when the slit pitch W 4  was 300 micrometers or less. 
     Therefore, it is preferable that the slit pitch W 4  be 500 micrometers or less, and more preferably be 300 micrometers or less. 
     (Operation and Action) 
     An overall operation of the display device with the touch detection function  40  illustrated in  FIGS. 4 and 5  according to the first embodiment will now be described. 
     The Vcom generating section  41  generates the drive signal Vcom, and supplies the same to the drive electrode driver  43 . The drive electrode driver  43  supplies, based on the control signal supplied from the drive control circuit  42 , the drive signal Vcom to the plurality of drive electrodes  33  in the touch detection function display unit  44  in a sequential fashion. 
     Each of the touch detection electrodes  34  of the touch sensor  441  outputs the detection signal Vdet based on the basic principle of the electrostatic capacitance type touch detection described above. The detection signal Vdet may include a waveform having a rising and a falling that are synchronized with a timing of a voltage change in the drive signal Vcom. The multiplexer  47  sequentially switches the sources from which the detection signal Vdet, outputted from each of the touch detection electrodes  34  of the touch sensor  441 , is to be obtained so as to obtain the detection signal Vdet therefrom in order, and supplies the same to the detection circuit  48 . In the detection circuit  48 , the analog LPF section  51  removes a high-frequency component from the detection signal Vdet, and outputs the detection signal Vdet subjected to the high-frequency component removal as a detection signal Vdet2. The A/D converting section  52  converts the detection signal Vdet2 supplied from the analog LPF section  51  into a digital signal. The signal processing section  53  performs, based on the output signal from the A/D converting section  52 , a logic operation to detect the presence or absence of the touch performed on the touch sensor  441 . The coordinate extracting section  54  detects, based on a result of the touch detection in the signal processing section  53 , a touch coordinate on the touch sensor  441 . Thus, when a user has touched the touch panel, a position at which the touch has been made by the user is detected. 
     The source driver  46  supplies the image signal to the liquid crystal display unit  442 . The gate driver  45  supplies the liquid crystal display unit  442  with a selection signal (a gate signal) by which a horizontal pixel line subjected to displaying is selected. The liquid crystal display unit  442  performs scanning throughout the entire screen based on those signals and the drive signal Vcom to display an image on the screen. More specifically, with reference to  FIG. 6 , the image signal supplied through the source line  25  is applied to the pixel electrode  22  of the liquid crystal element LC through the TFT element Tr of the display pixels  20  selected in a line-sequential fashion by the gate line  26 , and the drive signal Vcom is applied to the common electrode (the drive electrode  33 ). Thus, pixel data is written into the liquid crystal element LC, by which displaying of an image is performed. 
     (Effect) 
     In the display device with the touch detection function  40  according to the first embodiment of the technology, each of the drive electrodes  33  is provided with the one or more inner-electrode slits  33 A, and the inter-electrode slit  33 B corresponding to the inner-electrode slit  33 A is formed between the two adjacent drive electrodes  33 . This makes it possible to reduce a structural difference between a portion where the drive electrode  33  is formed and a portion between the two adjacent drive electrodes  33 . Hence, it is possible to uniformize the states of orientation of the liquid crystal molecules in the liquid crystal display unit  442  throughout the entire display region. Also, the width of the drive electrode  33  has the size corresponding to two or more pixel electrodes  22 , making it possible to keep down a circuit magnitude and the number of wirings used for the drive electrodes  33 . Therefore, it is possible to keep down the circuit magnitude and the number of wirings and to suppress deterioration in display quality while using the plurality of drive electrodes  33 . 
     Second Embodiment 
     A display device with a touch detection function according to a second embodiment of the technology will now be described. Note that the same or equivalent elements as those of the display device with the touch detection function  40  according to the first embodiment described above are denoted with the same reference numerals, and will not be described in detail. 
     In the first embodiment described above, the touch detection function display unit  44  has the configuration in which: the liquid crystal display unit  442  including the liquid crystals in any of the various modes such as the TN mode and the ECB mode; and the touch sensor  441  are integrated. The second embodiment has a configuration in which: a liquid crystal display unit including liquid crystals in a transverse electric mode such as an FFS (Fringe Field Switching) mode and an IPS (In-Plane Switching) mode; and a touch sensor are integrated. 
     In the second embodiment where the liquid crystals in the transverse electric mode are employed, a touch detection function display unit  44 B may be configured as illustrated in  FIG. 16 .  FIG. 16  illustrates an example of a cross-sectional configuration of a main part of the touch detection function display unit  44 B. Referring to  FIG. 16 , a liquid crystal layer  6 B is sandwiched between a pixel substrate  2 B and an opposed substrate  3 B. Since names, functions, etc. of other elements are the same as those in the first embodiment described with reference to  FIG. 5 , those elements will not be described in detail. Unlike the first embodiment of  FIG. 5 , the drive electrodes  33  in this embodiment, which are shared for both the displaying and the touch detection, are formed immediately above the TFT substrate  21 , and structure a part of the pixel substrate  2 B. The pixel electrodes  22  are arranged above the drive electrodes  33  with an insulating layer  23  in between. In this embodiment, all of dielectrics, including the liquid crystal layer  6 B as well, between the drive electrodes  33  and the touch detection electrodes  34  contribute to the formation of the electrostatic capacitance C 1 . 
     A more detailed description is provided with reference to  FIGS. 17A and 17B . In a transverse liquid crystal element illustrated in  FIGS. 17A and 17B , the drive electrodes (common electrodes)  33 , formed on the pixel substrate  2 B, are provided thereon with the pixel electrodes  22  via the insulating layer  23 . The pixel electrodes  22  may be those patterned like teeth of a comb, and an alignment film  27  is so formed as to cover the pixel electrodes  22 . The liquid crystal layer  6 B is sandwiched between the alignment film  27  and an alignment film  36  provided on the opposing substrate  3 B side. The two polarizing plates  24  and  35  are disposed in crossed nicols. Rubbing directions of the two alignment films  27  and  36  correspond to a direction of a light-transmission axis of one of the two polarizing plates  24  and  35 .  FIGS. 17A and 17B  illustrate an example where the rubbing directions coincide with the light-transmission axis of the polarizing plate  35  on a light-exit side. Further, in this example, the rubbing directions of the two alignment films  27  and  36  and the direction of the light-transmission axis of the polarizing plate  35  are so set as to be almost parallel to an extending direction of the pixel electrodes  22  (a longitudinal direction of the comb teeth) within a range in which a direction of rotation of the liquid crystal molecules is defined. 
     An operation of the touch detection function display unit  44 B having the configuration discussed above will now be described. 
     Here, description will be given briefly on a principle of a displaying operation in the transverse liquid crystal element with reference to  FIGS. 17A to 18B . In  FIGS. 17A to 18B ,  FIGS. 17A and 18A  each illustrate a state of the liquid crystal element when no electric field is applied, and  FIGS. 17B and 18B  each illustrate a state of the liquid crystal element when the electric field is applied. 
     In the state where a voltage is not applied between the drive electrode  33  and the pixel electrodes  22  ( FIGS. 17A and 18A ), axes of liquid crystal molecules  61  configuring the liquid crystal layer  6 B are orthogonal to the light-transmission axis of the polarizing plate  24  on a light-incidence side, and are parallel to the light-transmission axis of the polarizing plate  35  on the light-exit side. Thus, incident light h, which has transmitted through the polarizing plate  24  on the light-incidence side, reaches the polarizing plate  35  on the light-exit side without causing a phase difference in the liquid crystal layer  6 B, and is absorbed by the polarizing plate  35 , leading to black displaying. On the other hand, in the state where the voltage is applied between the drive electrode  33  and the pixel electrodes  22  ( FIGS. 17B and 18B ), orientation directions of the liquid crystal molecules  61  are rotated in an oblique direction with respect to the extending direction of the pixel electrodes  22  by an electric field (transverse electric field) E generated between the pixel electrodes  22 . At this time, an intensity of the electric field E in white displaying is so optimized that the liquid crystal molecules  61  located in the center in a thickness direction of the liquid crystal layer  6 B are rotated by about 45 degrees. Thus, the incident light h, which has transmitted through the polarizing plate  24  on the light-incidence side, causes therein the phase difference while the incident light h passes through the liquid crystal layer  6 B. Hence, the incident light h becomes linearly-polarized light which is rotated at 90 degrees, and the linearly-polarized light passes through the polarizing plate  35  on the light-exit side, leading to the white displaying. 
     The display device with the touch detection function, utilizing the liquid crystals in the transverse electric mode described above, also achieves effects similar to those according to the first embodiment described above, by allowing the plurality of drive electrodes  33  to have the configuration in which the inner-electrode slit  33 A and the inter-electrode slit  33 B are provided as in the first embodiment described above. 
     Third Embodiment 
     A display device with a touch detection function according to a third embodiment of the technology will now be described. Note that the same or equivalent elements as those of the display devices with the touch detection function according to the first and the second embodiments described above are denoted with the same reference numerals, and will not be described in detail. 
     The display device with the touch detection function according to the third embodiment utilizes the liquid crystals in the transverse electric mode as in the second embodiment described above, and has a basic configuration which is similar to the configuration of the touch detection function display unit  44 B illustrated in  FIG. 16 . The third embodiment differs from the second embodiment where the drive electrodes  33  has the configuration similar to that of the first embodiment as discussed above, in that a configuration of the inner-electrode slits  33 A in the drive electrodes  33  is partially modified. 
       FIG. 19  illustrates the configuration of the drive electrodes  33  according to the third embodiment. In the above-described first and the second embodiments, the inner-electrode slits  33 A are provided continuously to extend in the first direction (the horizontal direction) as illustrated in  FIG. 11 . In contrast, in this embodiment, the inner-electrode slits  33 A are not continuous in the first direction, and discontinuous regions  33 C are partially formed to provide slits in an intermittent fashion. 
     For the purpose of describing an effect obtained by the provision of the discontinuous regions  33 C, description will be given in detail on a configuration of the pixel substrate  2 B, especially on a wiring layer in the TFT substrate  21 , according to the third embodiment with reference to  FIGS. 20 and 21 . 
     The pixel substrate  2 B has the configuration in which the TFT element Tr as well as the wiring layer thereof, the drive electrode  33 , and the pixel electrode  22  are stacked in order on a substrate  71 . The substrate  71  can be a glass substrate, for example. In the TFT element Tr and its wiring layer, the source line (image signal line)  25  is formed on the gate line (scanning line)  26  through a gate insulating film  72 . The drive electrode  33  is formed on the source line  25  with an insulating layer  73  in between. The pixel electrode  22  and the TFT element Tr are in conduction with one another through a contact hole  74 . 
     As illustrated in  FIG. 21 , the source line  25  extends in the second direction (the perpendicular direction).  FIG. 21  illustrates an exemplary configuration where the pixel electrode  22  has a bent portion  28  and a pixel electrode slit  29 . Each of the pixel electrodes  22  illustrated in  FIG. 21  may correspond to a sub-pixel. 
     In the pixel substrate  2 B, the plurality of drive electrodes  33  are provided on the opposed substrate  3 B side relative to the image signal wirings (the source lines  25 ). In this embodiment, the inner-electrode slit  33 A is discontinuous at an intersection of the inner-electrode slit  33 A and the image signal wiring as viewed from the opposed substrate  3 B. Also, the inner-electrode slit  33 A is so formed that the image signal wiring and an electrode part of the drive electrode  33  overlap one another at the intersection as viewed from the opposed substrate  3 B. In other words, in this embodiment, the portion in which the inner-electrode slit  33 A and the image signal wiring intersect one another serves as the discontinuous region  33 C where the inner-electrode slit  33 A is not provided. This allows the image signal wiring to be covered with the electrode part of the drive electrode  33  as viewed from the opposed substrate  3 B side. Thus, as illustrated in  FIG. 22 , a signal noise component from the image signal wiring (the source line  25 ) is shielded by the drive electrode  33 . 
       FIG. 23  illustrates an electrode configuration according to a comparative example with respect to the third embodiment. In the comparative example, the inner-electrode slits  33 A are provided continuously to extend in the horizontal direction. In other words, in the comparative example, the inner-electrode slit  33 A is provided also at the position corresponding to the discontinuous region  33 C of the drive electrode  33  in the third embodiment. It is likely in the configuration according to the comparative example that the signal noise component from the image signal line (the source line  25 ) leaks toward the opposed substrate  3 B through the inner-electrode slit  33 A. The signal noise component may affect the performance in detection when the signal noise component reaches the touch detection electrode  34  provided on the opposed substrate  3 B side. In contrast, according to the third embodiment, the inner-electrode slit  33 A includes the discontinuous region  33 C in the drive electrode  33 , making it possible to prevent such an influence on the detection performance from occurring. Also, the provision of the discontinuous region  33 C makes it possible to lower a resistance of the drive electrode  33  than the case where the continuous inner-electrode slit  33 A is provided. 
     APPLICATION EXAMPLES 
     Application examples of the display devices with the touch detection function according to the embodiments described above will now be described with reference to  FIGS. 25 to 29G . Each of the display devices with the touch detection function according to the embodiments is applicable to any electronic unit in any field. The electronic unit may be, for example but not limited to, a television device, a digital camera, a computer including a desk-top personal computer and a laptop personal computer, a portable terminal device including a cellular phone, a video camera, or any other suitable devices. In other words, the display devices with the touch detection function according to the embodiments are applicable to electronic units in all of fields, which display, as an image or a video image, a video signal inputted from the outside or generated internally. 
     First Application Example 
       FIG. 25  illustrates an external appearance of a television device to which the display device with the touch detection function according to any one of the embodiments described above is applied. The television device is provided with an image display screen unit  510  including a front panel  511  and a filter glass  512 , for example. The image display screen unit  510  includes the display device with the touch detection function according to any one of the embodiments described above. 
     Second Application Example 
       FIGS. 26A and 26B  each illustrate an external appearance of a digital camera to which the display device with the touch detection function according to any one of the embodiments described above is applied. The digital camera is provided with a light emitting unit  521  for flash, a display unit  522 , a menu switch section  523 , and a shutter-release button  524 , for example. The display unit  522  includes the display device with the touch detection function according to any one of the embodiments described above. 
     Third Application Example 
       FIG. 27  illustrates an external appearance of laptop personal computer to which the display device with the touch detection function according to any one of the embodiments described above is applied. The laptop personal computer is provided with a body  531 , a keyboard  532  for input-manipulation of characters and the like, and a display unit  533  for displaying an image, for example. The display unit  533  includes the display device with the touch detection function according to any one of the embodiments described above. 
     Fourth Application Example 
       FIG. 28  illustrates an external appearance of a video camera to which the display device with the touch detection function according to any one of the embodiments described above is applied. The video camera is provided with a body  541 , a lens  542  provided in a front face of the body  541  for picking-up an image of an object, a shooting start/stop switch  543 , and a display unit  544 , for example. The display unit  544  includes the display device with the touch detection function according to any one of the embodiments described above. 
     Fifth Application Example 
       FIGS. 29A to 29G  each illustrate an external appearance of a cellular phone to which the display device with the touch detection function according to any one of the embodiments described above is applied. The cellular phone couples an upper casing  710  and a lower casing  720  through a coupling part (or a hinge)  730 , and is provided with a display  740 , a sub-display  750 , a picture light  760 , and a camera  770 , for example. The display  740  or the sub-display  750  includes the display device with the touch detection function according to any one of the embodiments described above. 
     The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2010-187175 filed in the Japan Patent Office on Aug. 24, 2010, the entire content of which is hereby incorporated by reference. 
     Although the technology has been described in terms of exemplary embodiments, it is not limited thereto. It should be appreciated that variations may be made in the described embodiments by persons skilled in the art without departing from the scope of the technology as defined by the following claims. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in this specification or during the prosecution of the application, and the examples are to be construed as non-exclusive. For example, in this disclosure, the term “preferably”, “preferred” or the like is non-exclusive and means “preferably”, but not limited to. The use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Moreover, no element or component in this disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.