Patent Publication Number: US-2022236831-A1

Title: Detecting device and display device with touch detection function

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority from Japanese Patent Application No. 2021-011881 filed on Jan. 28, 2021, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a detecting device and a display device with a touch detection function. 
     2. Description of the Related Art 
     There have recently been demands for achieving a fingerprint detection used for personal authentication, for example, by a capacitive system. To detect a fingerprint, electrodes having a smaller area are used than in detecting contact of a hand or a finger. If signals are acquired from small electrodes, code division multiplexing drive can achieve satisfactory detection sensitivity. The code division multiplexing drive is a drive system that simultaneously selects a plurality of drive electrodes and supplies drive signals the phase of which is determined based on a predetermined code to the selected drive electrodes (refer to Japanese Patent Application Laid-open Publication No. 2012-118957 A). 
     Detecting devices that perform the code division multiplexing drive may possibly have larger power consumption than detecting devices that sequentially drive a plurality of drive electrodes in a time-division manner. 
     An object of the present disclosure is to provide a detecting device that can reduce power consumption. 
     SUMMARY 
     A detecting device according to an embodiment of the present disclosure includes a plurality of drive electrodes arrayed in a first direction, a plurality of detection electrodes arrayed in a second direction intersecting the first direction, a drive signal supply circuit configured to supply a drive signal to the drive electrodes, and a plurality of switch elements configured to switch between coupling and decoupling between the drive electrodes. The drive electrodes include at least a first drive electrode and a second drive electrode disposed side by side in the first direction, the drive signal supply circuit supplies a first voltage signal to one of the first drive electrode and the second drive electrode and supplies a second voltage signal having an electric potential different from an electric potential of the first voltage signal to another one of the first drive electrode and the second drive electrode, and the switch elements switch between coupling and decoupling of at least the first drive electrode and the second drive electrode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a display device according to a first embodiment; 
         FIG. 2  is a sectional view along line II-II′ of  FIG. 1 ; 
         FIG. 3  is a plan view illustrating an example of the configuration of a detecting device according to the first embodiment; 
         FIG. 4  is a block diagram illustrating an example of the configuration of the detecting device according to the first embodiment; 
         FIG. 5  is a diagram for explaining an example of an operation in code division multiplexing drive; 
         FIG. 6  is a diagram for explaining a coupling configuration of a plurality of drive electrodes; 
         FIG. 7  is a timing waveform chart for explaining a method for driving the drive electrodes; 
         FIG. 8  is a timing waveform chart for explaining an operation of switching first switch elements and a second switch element; 
         FIG. 9  is a diagram for explaining the method for driving the drive electrodes in a first period, a second period, and a third period; 
         FIG. 10  is a diagram for explaining a coupling configuration of a plurality of drive electrodes and a plurality of detection electrodes in a detecting device according to a second embodiment; 
         FIG. 11  is a timing waveform chart for explaining the method for driving the drive electrodes and the coupling configuration of the detection electrodes; 
         FIG. 12  is a timing waveform chart for explaining an operation of switching the first switch elements, the second switch element, and a third switch element; 
         FIG. 13  is a diagram for explaining a coupling configuration of a plurality of drive electrodes according to a third embodiment; 
         FIG. 14  is a diagram for explaining a coupling configuration of a plurality of drive electrodes according to a first modification of the third embodiment; 
         FIG. 15  is a diagram for explaining a coupling configuration of a plurality of drive electrodes according to a second modification of the third embodiment; 
         FIG. 16  is a diagram for explaining a coupling configuration of a plurality of drive electrodes according to a fourth embodiment in a first period; 
         FIG. 17  is a diagram for explaining the coupling configuration of the drive electrodes according to the fourth embodiment in a second period; 
         FIG. 18  is a diagram for explaining the coupling configuration of the drive electrodes according to a third modification of the fourth embodiment; 
         FIG. 19  is a plan view illustrating an example of a configuration of a detecting device according to a fifth embodiment; 
         FIG. 20  is a diagram for explaining a method for driving the detecting device according to the fifth embodiment; 
         FIG. 21  is a diagram for explaining a method for driving a detecting device according to a fourth modification of the fifth embodiment; 
         FIG. 22  is a plan view of an example of a configuration of a detecting device according to a sixth embodiment; and 
         FIG. 23  is a sectional view of a schematic sectional configuration of a detecting device according to a seventh embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary aspects (embodiments) to embody the present disclosure are described below in greater detail with reference to the accompanying drawings. The contents described in the embodiments are not intended to limit the present disclosure. Components described below include components easily conceivable by those skilled in the art and components substantially identical therewith. Furthermore, the components described below may be appropriately combined. What is disclosed herein is given by way of example only, and appropriate modifications made without departing from the spirit of the present disclosure and easily conceivable by those skilled in the art naturally fall within the scope of the disclosure. To make the explanation more specific, the drawings may possibly illustrate the width, the thickness, the shape, and other elements of each component more schematically than the actual aspect. These elements, however, are given by way of example only and are not intended to limit interpretation of the present disclosure. In the present specification and the drawings, components similar to those previously described with reference to previous drawings are denoted by like reference numerals, and detailed explanation thereof may be appropriately omitted. 
     To describe an aspect where a first structure is disposed on a second structure in the present specification and the claims, the term “on” includes both of the following cases unless otherwise noted: a case where the first structure is disposed directly on the second structure in contact with the second structure, and a case where the first structure is disposed on the second structure with another structure interposed therebetween. 
     First Embodiment 
       FIG. 1  is a plan view of a display device according to a first embodiment.  FIG. 2  is a sectional view along line II-II′ of  FIG. 1 . As illustrated in  FIGS. 1 and 2 , a display device  1  according to the present embodiment has a detection region FA and a frame region GA provided outside the detection region FA. The detection region FA is a region for detecting recesses and protrusions on the surface of an object to be detected, such as a finger Fg, in contact with or in proximity to a cover member  80 . In the display device  1  according to the present embodiment, a display region of a display panel  30  is identical or substantially identical with the detection region FA of a detecting device  100 . As a result, the display device  1  can detect a fingerprint on the whole display region. The shape of the display region and the detection region FA is a rectangle, for example. 
     As illustrated in  FIG. 2 , the display device  1  includes the display panel  30  and the detecting device  100 . The detecting device  100  includes a sensor  10  and the cover member  80 . The cover member  80  is a plate-like member having a first surface  80   a  and a second surface  80   b  opposite to the first surface  80   a . The first surface  80   a  of the cover member  80  serves not only as a detection surface for detecting recesses and protrusions on the surface of the finger Fg or the like in contact with or in proximity to the cover member  80  but also as a display surface on which an observer visually recognizes an image on the display panel  30 . The sensor  10  and the display panel  30  are provided on the second surface  80   b  of the cover member  80 . The cover member  80  is a member for protecting the sensor  10  and the display panel  30 , and covers the sensor  10  and the display panel  30 . The cover member  80  is a glass or resin substrate, for example. 
     The cover member  80 , the sensor  10 , and the display panel  30  are not limited to the configuration having a rectangular shape in planar view and may have other shapes, such as circular and elliptic shapes and an irregular shape obtained by removing part of these outer shapes. The cover member  80  is not limited to a plate shape. If the display region and the detection region FA have a curved surface, or if the frame region GA has a curved surface curved toward the display panel  30 , for example, the cover member  80  may have a curved surface. In this case, the display device  1  is a curved surface display with a fingerprint detection function and can detect a fingerprint on the curved surface of the curved surface display. The detecting device  100  is not limited to the configuration of being stacked on the display panel  30  and may be configured as a single fingerprint detecting device without providing the display panel  30 , which will be described later. 
     In the present specification, “planar view” refers to a positional relation viewed from a direction perpendicular to a first surface  101   a  of a substrate  101  illustrated in  FIG. 3 , which will be described later. The direction perpendicular to the first surface  101   a  is the “normal direction (third direction Dz) of the substrate  101 ”. 
     As illustrated in  FIGS. 1 and 2 , the second surface  80   b  of the cover member  80  is provided with a decorative layer  81  in the frame region GA. The decorative layer  81  is a colored layer having light transmittance lower than that of the cover member  80 . The decorative layer  81  can prevent wiring, circuits, and other components provided overlapping the frame region GA from being visually recognized by the observer. While the decorative layer  81  is provided on the second surface  80   b  in the example illustrated in  FIG. 2 , it may be provided on the first surface  80   a . The decorative layer  81  is not limited to a single layer and may be composed of a plurality of layers. 
     The sensor  10  is a detector for detecting recesses and protrusions on the surface of the finger Fg or the like in contact with or in proximity to the first surface  80   a  of the cover member  80 . As illustrated in  FIG. 2 , the sensor  10  is provided between the cover member  80  and the display panel  30 . The sensor  10  overlaps the detection region FA and part of the frame region GA when viewed from a direction perpendicular to the first surface  80   a  (normal direction). The sensor  10  is coupled to a wiring substrate  76  in the frame region GA. The wiring substrate  76  is provided with a detection IC (not illustrated) for controlling detection operations of the sensor  10 . The wiring substrate  76  is a flexible printed circuit board, for example. 
     A first surface of the sensor  10  is bonded to the second surface  80   b  of the cover member  80  with an adhesive layer  71  interposed therebetween. A second surface of the sensor  10  is bonded to a polarizing plate  35  of the display panel  30  with an adhesive layer  72  interposed therebetween. The adhesive layers  71  and  72  are made of translucent adhesive or resin and allow visible light to pass therethrough. 
     The display panel  30  includes a pixel substrate  30 A, a counter substrate  30 B, a polarizing plate  34 , and the polarizing plate  35 . The polarizing plate  34  is provided under the pixel substrate  30 A. The polarizing plate  35  is provided on the counter substrate  30 B. The pixel substrate  30 A is coupled to a display IC (not illustrated) for controlling display operations of the display panel  30  through a wiring substrate  75 . The display panel  30  according to the present embodiment is a liquid crystal panel including liquid crystal display elements serving as a display functional layer. The display panel  30  is not limited thereto and may be an organic light-emitting diode (OLED) display panel including OLEDs as electro luminescence (EL) elements for display elements or a display panel including electrophoretic elements for display elements, for example. 
     The detection IC and the display IC described above may be provided to a control substrate outside the module. Alternatively, the detection IC may be provided to the substrate  101  (refer to  FIG. 3 ) of the sensor  10 . The display IC may be provided to the pixel substrate  30 A. 
     The following describes the configuration of the detecting device  100  in greater detail.  FIG. 3  is a plan view illustrating an example of the configuration of the detecting device according to the first embodiment. As illustrated in  FIG. 3 , the detecting device  100  includes the substrate  101  and the sensor  10  provided on the first surface  101   a  of the substrate  101 . The sensor  10  includes a plurality of drive electrodes Tx and a plurality of detection electrodes Rx. The substrate  101  is a translucent glass substrate that can allow visible light to pass therethrough. The substrate  101  may be a translucent resin substrate or resin film made of resin, such as polyimide. The sensor  10  is a translucent sensor. 
     The drive electrodes Tx and the detection electrodes Rx are provided in the detection region FA. The drive electrodes Tx are disposed side by side in a first direction Dx. The drive electrodes Tx extend in the second direction Dy. The detection electrodes Rx are disposed side by side in the second direction Dy. The detection electrodes Rx extend in the first direction Dx. As described above, the detection electrodes Rx extend in a direction intersecting the extending direction of the drive electrodes Tx. Each detection electrode Rx is coupled to the wiring substrate  76  provided in the frame region GA of the substrate  101  through frame wiring (not illustrated) and a detection electrode selection circuit  14 . The wiring substrate  76  is coupled to a side of the substrate  101  provided with the detection electrode selection circuits  14 . 
     The first direction Dx is one direction in a plane parallel to the substrate  101  and is a direction parallel to one side of the detection region FR, for example. The second direction Dy is one direction in the plane parallel to the substrate  101  and is a direction orthogonal to the first direction Dx. The second direction Dy may intersect the first direction Dx without being orthogonal thereto. The third direction Dz is a direction orthogonal to the first direction Dx and the second direction Dy, and is a direction vertical to the first surface  101   a  of the substrate  101 . 
     The drive electrode Tx is formed in a rectangular shape, and the detection electrode Rx is formed in a zigzag-line shape. The configuration is not limited thereto, and the shape and the arrangement pitch of the drive electrodes Tx and the detection electrodes Rx can be appropriately changed. The drive electrodes Tx are made of translucent conductive material, such as indium tin oxide (ITO). The detection electrodes Rx are made of metal material, such as aluminum or an aluminum alloy. Alternatively, the drive electrodes Tx may be made of metal material, and the detection electrodes Rx may be formed by ITO. The drive electrodes Tx and the detection electrodes Rx may be made of the same material. An insulating layer (not illustrated) is interposed between the drive electrodes Tx and the detection electrodes Rx. 
     Capacitance is formed at the intersections of the detection electrodes Rx and the drive electrodes Tx. The sensor  10  performs touch detection and fingerprint detection based on a change in capacitance between the detection electrodes Rx and the drive electrodes Tx. The sensor  10  performs, by code division multiplexing drive (hereinafter, referred to as CDM drive), a fingerprint detection operation by a mutual capacitive system. Specifically, a drive electrode selection circuit  15  simultaneously selects a plurality of drive electrodes Tx. The drive electrode selection circuit  15  supplies drive signals VTP the phase of which is determined based on a predetermined code to the selected drive electrodes Tx. The detection electrodes Rx output detection signals Vdet corresponding to a change in capacitance due to the recesses and protrusions on the surface of a finger or the like in contact with or in proximity to the sensor  10 . As a result, the sensor  10  performs fingerprint detection. 
     When the drive electrode selection circuit  15  performs touch detection, it may perform touch detection by sequentially driving a plurality of drive electrodes Tx in a time-division manner or sequentially selecting and driving each drive electrode block including a plurality of drive electrodes Tx. 
     While various circuits, such as the detection electrode selection circuits  14  and the drive electrode selection circuits  15 , are provided in the frame region GA of the substrate  101  in  FIG. 3 , this configuration is given by way of example only. At least part of the various circuits may be included in the detection IC mounted on the wiring substrate  76 . 
       FIG. 4  is a block diagram illustrating an example of the configuration of the detecting device according to the first embodiment. As illustrated in  FIG. 4 , the detecting device  100  includes the sensor  10 , a detection controller  11 , the drive electrode selection circuit  15 , a detection electrode selection circuit  14 , and a detection circuit  40 . 
     The detection controller  11  is a circuit that controls detection operations of the sensor  10 . The drive electrode selection circuit  15  is a circuit that supplies the drive signals VTP for detection to the drive electrodes Tx of the sensor  10  based on control signals supplied from the detection controller  11 . The detection electrode selection circuit  14  selects the detection electrodes Rx of the sensor  10  and couples them to the detection circuit  40  based on control signals supplied from the detection controller  11 . 
     The detection circuit  40  is a circuit that detects the shape of a fingerprint by detecting the recesses and protrusions on the surface of a finger or the like in contact with or in proximity to the first surface  80   a  of the cover member  80  based on the control signals supplied from the detection controller  11  and the detection signals Vdet output from the detection electrodes Rx. The detection circuit  40  includes a detection signal amplifier  42 , an A/D converter  43 , a signal processor  44 , a coordinate extractor  45 , a synthesizer  46 , and a detection timing controller  47 . The detection timing controller  47  controls the detection signal amplifier  42 , the A/D converter  43 , the signal processor  44 , the coordinate extractor  45 , and the synthesizer  46  such that they operate synchronously with one another based on the control signals supplied from the detection controller  11 . 
     The detection signals Vdet are supplied from the sensor  10  to the detection signal amplifier  42  of the detection circuit  40 . The detection signal amplifier  42  amplifies the detection signals Vdet. The A/D converter  43  converts analog signals output from the detection signal amplifier  42  into digital signals. 
     The signal processor  44  is a logic circuit that detects whether a finger is in contact with or in proximity to the sensor  10  based on the output signals from the A/D converter  43 . The signal processor  44  performs processing of extracting a signal (absolute value |ΔV|) of the difference between the detection signals due to the finger. The signal processor  44  compares the absolute value |ΔV| with a predetermined threshold voltage. If the absolute value |ΔV| is lower than the threshold voltage, the signal processor  44  determines that the object to be detected is in a non-contact state or is sufficiently far away from the detection position to determine that it is in a non-contact state. By contrast, if the absolute value |ΔV| is equal to or higher than the threshold voltage, the signal processor  44  determines that the object to be detected is in a contact state or is in sufficiently proximity to the detection position to determine that it is substantially in a contact state. As described above, the detection circuit  40  can detect contact or proximity of the object to be detected. 
     More specifically, the signal processor  44  calculates a plurality of detection signals Vdet supplied from the sensor  10  based on a predetermined code, and performs decoding on the calculated detection signals Vdet based on the predetermined code in CDM drive. An example of the operations in CDM drive will be described later in greater detail. 
     The coordinate extractor  45  is a logic circuit that calculates, when the signal processor  44  detects contact or proximity of a finger, the detection coordinates of the finger. The coordinate extractor  45  outputs the detection coordinates to the synthesizer  46 . The synthesizer  46  combines the detection signals Vdet output from the sensor  10 , thereby generating two-dimensional information indicating the object to be detected in contact with or in proximity to the sensor  10 . The synthesizer  46  outputs the two-dimensional information as output Vout from the detection circuit  40 . Alternatively, the synthesizer  46  may generate an image based on the two-dimensional information and output the image information as the output Vout. 
     The detection IC described above functions as the detection circuit  40  illustrated in  FIG. 4 . Part of the functions of the detection circuit  40  may be included in the display IC described above or be provided as functions of an external micro-processing unit (MPU). 
     The following describes CDM drive performed by the detecting device  100 .  FIG. 5  is a diagram for explaining an example of an operation in code division multiplexing drive. To simplify the explanation,  FIG. 5  illustrates an example of the operation in CDM drive performed on four drive electrodes Tx- 1 , Tx- 2 , Tx- 3 , and Tx- 4 . 
     As illustrated in  FIG. 5 , the drive electrode selection circuit  15  (refer to  FIG. 4 ) simultaneously selects four drive electrodes Tx- 1 , Tx- 2 , Tx- 3 , and Tx- 4  of a drive electrode block BK. The drive electrode selection circuit  15  supplies the drive signals VTP the phase of which is determined based on a predetermined code to the drive electrodes Tx. 
     The predetermined code is defined by a square matrix H in Expression (1), for example. The order of the square matrix H is four, which is equal to the number of drive electrodes Tx- 1 , Tx- 2 , Tx- 3 , and Tx- 4 . The predetermined code is based on the square matrix H the elements of which are either “1” or “−1” or either “1” or “0” and two desired different rows of which are an orthogonal matrix. The predetermined code is based on a Hadamard matrix, for example. The drive electrode selection circuit  15  applies the drive signals VTP such that the phase of AC rectangular waves corresponding to the element “1” is opposite to the phase of AC rectangular waves corresponding to the element “−1” based on the square matrix H in Expression (1). In other words, the element “−1” of the square matrix H in Expression (1) is an element for supplying the drive signal VTP determined to have a phase different from that of the element “1”. 
     
       
         
           
             
               
                 
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       FIG. 5  illustrates a case where an external proximity object CQ, such as the finger Fg, is present on a portion at which the drive electrode Tx- 2  out of the drive electrodes Tx- 1 , Tx- 2 , Tx- 3 , and Tx- 4  intersects the detection electrode Rx, for example. A voltage of difference due to the external proximity object CQ is generated (the voltage of difference is 20%, for example) by mutual induction at the intersection portion of the drive electrode Tx- 2  and the detection electrode Rx to which the external proximity object CQ is in proximity. In the example illustrated in  FIG. 5 , a signal obtained by integrating the detection signal corresponding to the element “1” and the detection signal corresponding to the element “−1” is output as the detection signal Vdet from the detection electrode Rx. 
     In a first period of time, the drive electrode selection circuit  15  supplies positive-polarity drive signals VTP to the drive electrodes Tx- 1 , Tx- 2 , Tx- 3 , and Tx- 4  corresponding to the elements (1,1,1,1) in the first row of the square matrix H (first code). The detection signal Vdet output from the detection electrode Rx and detected by the detection circuit  40  in the first period of time is calculated by: (1)+(0.8)+(1)+(1)=3.8. 
     In a second period of time, the drive electrode selection circuit  15  supplies positive-polarity drive signals VTP to the drive electrodes Tx- 1  and Tx- 3  and supplies negative-polarity drive signals VTP to the drive electrodes Tx- 2  and Tx- 4  corresponding to the elements (1,−1,1,−1) in the second row of the square matrix H (second code). The detection signal Vdet output from the detection electrode Rx and detected by the detection circuit  40  in the second period of time is calculated by: (1)+(−0.8)+(1)+(−1)=0.2. 
     Similarly, the detection signal Vdet in a third period of time (third code) is calculated by: (1)+(0.8)+(−1)+(−1)=−0.2. The detection signal Vdet in a fourth period of time (fourth code) is calculated by: (1)+(−0.8)+(−1)+(1)=0.2. 
     The signal processor  44  multiplies the detection signals Vdet (Vdet=(3.8,0.2,−0.2,0.2)) output from the detection electrode Rx and detected in each period of time by the square matrix H in Expression (1), thereby performing decoding. As a result, the signal processor  44  derives “4.0, 3.2, 4.0, 4.0” as a decoded signal. The detection circuit  40  can detect that the external proximity object CQ, such as the finger Fg, is in contact with the position of the drive electrode Tx- 2  in the relation with the detection electrode Rx based on the decoded signal. As described above, the detecting device  100  can detect whether the external proximity of object CQ is in contact with the intersections of the drive electrodes Tx and the detection electrodes Rx. By making the pitch between the intersections of the drive electrodes Tx and the detection electrodes Rx as small as possible, the detecting device  100  can detect the recesses and protrusions (e.g., a fingerprint) on the surface of the external proximity object CQ. The coordinate extractor  45  outputs the touch panel coordinates or the decoded signal as the output Vout. 
     While  FIG. 5  illustrates the example of the operation in CDM drive performed on four drive electrodes Tx, CDM drive may be performed on five or more drive electrodes Tx. In this case, the predetermined code is defined by a square matrix the order of which corresponds to the number of drive electrodes Tx. The order of the matrix included in the predetermined code is not necessarily equal to the number of drive electrodes Tx included in one drive electrode block BK. 
       FIG. 6  is a diagram for explaining a coupling configuration of a plurality of drive electrodes. To simplify the explanation,  FIG. 6  illustrates four drive electrodes Tx- 1 , Tx- 2 , Tx- 3 , and Tx- 4  and four detection electrodes Rx- 1 , Rx- 2 , Rx- 3 , and Rx- 4 . 
     As illustrated in  FIG. 6 , the detecting device  100  further includes a drive signal supply circuit  20 , first switch elements SW 1 H and SW 1 L, second switch elements SW 2 , and wiring  21 ,  22 , and  23 . The drive signal supply circuit  20  is a circuit that supplies the drive signals VTP to the drive electrodes Tx. The drive signal supply circuit  20  may be included in the detection IC described above or be provided on the substrate  101 . 
     The drive signal supply circuit  20  includes a first voltage signal supplier  20   a  and a second voltage signal supplier  20   b . The first voltage signal supplier  20   a  is a circuit that supplies the drive electrodes Tx with first voltage signals VH having positive polarity corresponding to the element “1” of the square matrix H. The second voltage signal supplier  20   b  is a circuit that supplies the drive electrodes Tx with second voltage signals VL having negative polarity corresponding to the element “−1” of the square matrix H. The first voltage signal VH and the second voltage signal VL are voltage signals having different electric potentials. The first voltage signal VH and the second voltage signal VL are alternately repeated corresponding to the predetermined code, thereby forming the drive signal VTP. 
     The first switch elements SW 1 H and SW 1 L and the second switch elements SW 2  are included in the drive electrode selection circuit  15  (refer to  FIG. 4 ). The second switch elements SW 2  and the wiring  23  are disposed at a first end of the drive electrodes Tx in the extending direction (second direction Dy). The first switch elements SW 1 H and SW 1 L and the wiring  21  and  22  are disposed at a second end of the drive electrodes Tx in the extending direction (second direction Dy). In the following description, the first end of the drive electrodes Tx in the extending direction (second direction Dy) is referred to as the “left end”, and the second end is referred to as the “right end” with reference to  FIG. 6  and other drawings. The first switch elements SW 1 H and SW 1 L may be simply referred to as the first switch elements SW 1  when they need not be distinguished from each other. 
     First ends of the first switch elements SW 1 H and SW 1 L are coupled to the right end of one corresponding drive electrode Tx. A second end of each first switch element SW 1 H is coupled to the wiring  21 . A second end of each first switch element SW 1 L is coupled to the wiring  22 . When the first switch element SW 1 H is turned on (coupled state), the drive signal supply circuit  20  supplies the first voltage signals VH to the drive electrode Tx (drive electrodes Tx- 1  and Tx- 3  in  FIG. 6 ) through the wiring  21  and the first switch element SW 1 H. When the first switch element SW 1 L is turned on (coupling state), the drive signal supply circuit  20  supplies the second voltage signals VL to the drive electrode Tx (drive electrodes Tx- 2  and Tx- 4  in  FIG. 6 ) through the wiring  22  and the first switch element SW 1 L. To facilitate the reader&#39;s understanding, the drive electrodes Tx supplied with the first voltage signals VH and the drive electrodes Tx at an intermediate potential VI (refer to  FIG. 9 ) are hatched to be distinguished from the drive electrodes Tx supplied with the second voltage signals VL in  FIG. 6  and other drawings. 
     The first switch element SW 1 H and the first switch element SW 1 L perform operations opposite to each other. When the first switch element SW 1 H is turned on, the first switch element SW 1 L is turned off (decoupling state). When the first switch element SW 1 H is turned off, the first switch element SW 1 L is turned on. 
     As described above, the drive signals VTP (the first voltage signals VH or the second voltage signals VL) corresponding to the predetermined code are supplied by the operations of the first switch elements SW 1 H and SW 1 L. Let us focus on the drive electrodes Tx- 1  and Tx- 2  disposed side by side out of the drive electrodes Tx. In the example illustrated in  FIG. 6 , the drive signal supply circuit  20  supplies the first voltage signals VH to one of the drive electrode Tx- 1  (first drive electrode) and the drive electrode Tx- 2  (second drive electrode). The drive signal supply circuit  20  supplies the second voltage signals VL having an electric potential different from that of the first voltage signals VH to the other of the drive electrode Tx- 1  (first drive electrode) and the drive electrode Tx- 2  (second drive electrode). 
     First ends of the second switch elements SW 2  are coupled to the common wiring  23 . Second ends of the second switch elements SW 2  are coupled to the left ends of the respective drive electrodes Tx. When the second switch elements SW 2  are turned on, the drive electrodes Tx are coupled through the wiring  23  and the second switch elements SW 2 . In other words, when the second switch elements SW 2  are turned on, the drive electrodes Tx short out. The second switch elements SW 2  switch between coupling and decoupling of at least two drive electrodes Tx (e.g., the drive electrodes Tx- 1  and Tx- 2 ) supplied with the first voltage signals VH and the second voltage signals VL having different electrical potentials. 
       FIG. 7  is a timing waveform chart for explaining a method for driving the drive electrodes.  FIG. 8  is a timing waveform chart for explaining an operation of switching the first switch elements and the second switch element.  FIG. 9  is a diagram for explaining the method for driving the drive electrodes in a first period, a second period, and a third period. 
       FIGS. 7 to 9  illustrate an example where code inversion drive is performed in one code period (period for performing drive corresponding to the elements in a predetermined row of the square matrix H). As illustrated in  FIG. 7 , for example, the detecting device  100  has a first period TSp, a second period TSi, and a third period TSm. The first period TSp is a period for supplying the drive electrodes Tx with the drive signals VTP the phase of which is determined based on the predetermined code. The third period TSm is a code inversion period for supplying the drive electrodes Tx with the drive signals VTP the phase of which is determined based on a code obtained by inverting the polarity of the predetermined code. The second period TSi is a transition period provided between the first period TSp and the third period TSm. 
     As illustrated in  FIG. 7 , the periods are repeatedly arranged like the first period TSp, the second period TSi, the third period TSm, the second period TSi, the first period TSp, . . . . 
     In the first period TSp, as illustrated in  FIGS. 7 and 9 , the drive signal supply circuit  20  supplies the drive electrodes Tx with the drive signals VTP having a phase corresponding to the elements (1,−1,1,−1) in the second row of the square matrix H. Specifically, the drive electrodes Tx- 1  and Tx- 3  are supplied with the first voltage signals VH, and the drive electrodes Tx- 2  and Tx- 4  are supplied with the second voltage signals VL. In the first period TSp, one of the first switch elements SW 1 H and SW 1 L is turned on, and the other is turned off for each of the drive electrodes Tx based on the elements (1,−1,1,−1). In the first period TSp, all the second switch elements SW 2  are turned off, and the left ends of the drive electrodes Tx are decoupled from one another. 
     In the second period TSi, all the first switch elements SW 1  are turned off, and the drive electrodes Tx are decoupled from the drive signal supply circuit  20 . In other words, when the period is switched from the first period TSp to the second period TSi, supplying the first voltage signals VH to the drive electrodes Tx- 1  and Tx- 3  is stopped, and supplying the second voltage signals VL to the drive electrodes Tx- 2  and Tx- 4  is stopped. In addition to turning off the first switch elements SW 1 , the drive signal supply circuit  20  may also stop supplying electric potential to the wiring  21  and  22 . 
     In the second period TSi, all the second switch elements SW 2  are turned on, and the drive electrodes Tx are coupled through the wiring  23  and the second switch elements SW 2 . More specifically, as illustrated in  FIG. 8 , all the first switch elements SW 1  are turned off at time t 1 , and supplying the drive signals VTP (the first voltage signals VH and the second voltage signals VL) to the drive electrodes Tx is stopped. After a predetermined period of time has elapsed, all the second switch elements SW 2  are turned on at time t 2 , and the left ends of the drive electrodes Tx are coupled. 
     As described above, the drive electrodes Tx- 1  and Tx- 3  supplied with the first voltage signals VH and the drive electrodes Tx- 2  and Tx- 4  supplied with the second voltage signals VL are coupled. As a result, the electric potential of the drive electrodes Tx is the intermediate potential VI in the second period TSi. The intermediate potential VI is an electric potential between the first voltage signal VH and the second voltage signal VL and is ideally expressed by: VI=(VH+VL)/2. 
     In the third period TSm, code inversion drive is performed, and the drive electrodes Tx are driven based on the elements (−1,1,−1,1) obtained by inverting the polarity of the elements (1,−1,1,−1) in the second row of the square matrix H described above. In other words, the drive electrodes Tx- 1  and Tx- 3  are supplied with the second voltage signals VL, and the drive electrodes Tx- 2  and Tx- 4  are supplied with the first voltage signals VH. In the third period TSm, one of the first switch elements SW 1 H and SW 1 L is turned on, and the other is turned off for each of the drive electrodes Tx based on the inverted elements (−1,1,−1,1). All the second switch elements SW 2  are turned off, and the left ends of the drive electrodes Tx are decoupled from one another. 
     More specifically, as illustrated in  FIG. 8 , all the second switch elements SW 2  are turned off at time t 3 , and the left ends of the drive electrodes Tx are decoupled from one another. After a predetermined period of time has elapsed, all the first switch elements SW 1  are turned on at time t 4 , and the drive signals VTP (the first voltage signals VH and the second voltage signals VL) are supplied to the drive electrodes Tx. 
     Subsequently, drive is repeatedly performed like the third period TSm, the second period TSi, the first period TSp, the second period TSi, and the third period TSm as illustrated in  FIG. 7 . The electric potential of the drive signals VTP supplied to the drive electrodes Tx repeatedly changes like the first voltage signal VH, the intermediate potential VI, the second voltage signal VL, the intermediate potential VI, the first voltage signal VH, the intermediate potential VI, . . . . 
     While  FIGS. 7 to 9  illustrate an example where the intermediate potential VI is formed by the operations of the second switch elements SW 2  in code inversion drive, the detecting device  100  may perform the operations in the second period TSi when shifting from the drive corresponding to the elements in the second row of the square matrix H to the drive corresponding to the elements in the third row of the square matrix H. While  FIGS. 7 to 9  illustrate a case where the number of drive electrodes Tx supplied with the first voltage signals VH is equal to the number of drive electrodes Tx supplied with the second voltage signals VL to simplify the explanation, the present embodiment is not limited thereto. The number of drive electrodes Tx supplied with the first voltage signals VH may be different from the number of drive electrodes Tx supplied with the second voltage signals VL. In other words, the value of the intermediate potential VI also becomes a different potential depending on the number of drive electrodes Tx supplied with the first voltage signals VH and the number of drive electrodes Tx supplied with the second voltage signals VL. While  FIGS. 6 to 9  illustrate an example where the drive signals VTP (the first voltage signals VH or the second voltage signals VL) are supplied to four drive electrodes Tx- 1 , Tx- 2 , Tx- 3 , and Tx- 4  based on a predetermined code, the present embodiment is not limited thereto. The drive signals VTP may be supplied to all the drive electrodes Tx in the detection region FA. 
     As described above, the detecting device  100  according to the present embodiment includes a plurality of drive electrodes Tx, a plurality of detection electrodes Rx, the drive signal supply circuit  20 , and a plurality of second switch elements SW 2  (switch elements). The drive electrodes Tx are arrayed in the first direction Dx. The detection electrodes Rx are arrayed in the second direction Dy intersecting the first direction Dx. The drive signal supply circuit  20  supplies the drive signals VTP to the drive electrodes Tx. The second switch elements SW 2  switch between coupling and decoupling of the drive electrodes Tx. The drive electrodes Tx include at least the drive electrode Tx- 1  (first drive electrode) and the drive electrode Tx- 2  (second drive electrode) disposed side by side in the first direction Dx. The drive signal supply circuit  20  supplies the first voltage signal VH to one of the drive electrode Tx- 1  and the drive electrode Tx- 2  and supplies the second voltage signal VL having an electric potential different from that of the first voltage signal VH to the other of the drive electrode Tx- 1  and the drive electrode Tx- 2 . The second switch elements SW 2  switch between coupling and decoupling of at least the drive electrode Tx- 1  and the drive electrode Tx- 2 . 
     In the detecting device  100  according to the present embodiment, the electric potential of the drive electrodes Tx shifts from the first voltage signal VH to the second voltage signal VL through the intermediate potential VI or from the second voltage signal VL to the first voltage signal VH through the intermediate potential VI by the operations of the second switch elements SW 2  in the second period TSi. As a result, the drive signal supply circuit  20  can make the amplitude of the drive signals VTP supplied to the drive electrodes Tx (the potential difference between the intermediate potential VI and the first voltage signal VH or between the intermediate potential VI and the second voltage signal VL) smaller than the amplitude in drive for shifting the electric potential between the first voltage signal VH and the second voltage signal VL not through the intermediate potential VI. Consequently, the detecting device  100  can reduce power consumption. 
     Second Embodiment 
       FIG. 10  is a diagram for explaining the coupling configuration of a plurality of drive electrodes and a plurality of detection electrodes in the detecting device according to a second embodiment. In the following description, the same components as those described in the embodiment above are denoted by like reference numerals, and overlapping explanation thereof is omitted. 
     As illustrated in  FIG. 10 , the detection electrode selection circuit  14  in a detecting device  100 A according to the second embodiment includes third switch elements SW 3  corresponding to respective detection electrodes Rx- 1 , Rx- 2 , Rx- 3 , and Rx- 4 . The detection electrode selection circuit  14  switches the coupling state between the detection electrodes Rx and the detection circuit  40  by the operations of the third switch elements SW 3 . When the third switch elements SW 3  are turned on, the detection electrodes Rx are coupled to the detection circuit  40  and output the detection signals Vdet to the detection circuit  40 . When the third switch elements SW 3  are turned off, the detection electrodes Rx are decoupled from the detection circuit  40 . The detection electrodes Rx are not coupled to anywhere and are in a floating state. 
       FIG. 11  is a timing waveform chart for explaining the method for driving the drive electrodes and the coupling configuration of the detection electrodes.  FIG. 12  is a timing waveform chart for explaining an operation of switching the first switch elements, the second switch element, and the third switch element. 
     As illustrated in  FIG. 11 , the operations of the first switch elements SW 1  and the second switch elements SW 2  are the same as the first embodiment ( FIGS. 6 to 9 ) described above, and the waveforms of VTP supplied to the drive electrodes Tx are the same as the first embodiment ( FIGS. 6 to 9 ). The detection electrode selection circuit  14  turns on the third switch elements SW 3  in the first period TSp and the third period TSm (refer to  FIG. 10 ). As a result, the detection electrodes Rx are coupled to the detection circuit  40  and output the detection signals Vdet based on the predetermined code to the detection circuit  40 . 
     The detection electrode selection circuit  14  turns off the third switch elements SW 3  in the second period TSi. As a result, the detection electrodes Rx are decoupled from the detection circuit  40  and are in a floating state. 
     More specifically, as illustrated in  FIG. 12 , all the first switch elements SW 1  are turned off at time t 1 , and supplying the drive signals VTP (the first voltage signals VH and the second voltage signals VL) to the drive electrodes Tx is stopped. After a predetermined period of time has elapsed, the third switch elements SW 3  are turned off at time t 11  before time t 2 , and the detection electrodes Rx are decoupled from the detection circuit  40  (floating state). Subsequently, all the second switch elements SW 2  are turned on at time t 2 , and the left ends of the drive electrodes Tx are coupled. 
     All the second switch elements SW 2  are turned off at time t 3 , and the left ends of the drive electrodes Tx are decoupled from one another. After a predetermined period of time has elapsed, the third switch elements SW 3  are turned on at time t 31  before time t 4 , and the detection electrodes Rx are coupled to the detection circuit  40 . Subsequently, all the first switch elements SW 1  are turned on at time t 4 , and the drive signals VTP (the first voltage signals VH and the second voltage signals VL) are supplied to the drive electrodes Tx. 
     As described above, the detection electrodes Rx are brought into a floating state in the second period TSi by the operations of the third switch elements SW 3 . More specifically, time t 2  and t 3  when the second switch elements SW 2  are switched between turned on and off overlap the period of time when the third switch elements SW 3  are turned off, and they are positioned between time t 11  and time t 31  when the detection electrodes Rx are in a floating state. This mechanism can prevent noise due to the on-off operations of the second switch elements SW 2  from being superimposed on the detection signals Vdet output from the detection electrodes Rx. Consequently, the detecting device  100 A can suppress reduction in detection accuracy. 
     While the detection electrode selection circuit  14  turns on all the third switch elements SW 3  in  FIG. 10 , the present embodiment is not limited thereto. The detection electrode selection circuit  14  may turn on part of the third switch elements SW 3  and turn off the other part of the third switch elements SW 3 , thereby coupling the selected detection electrodes Rx to the detection circuit  40  in the first period TSp and the third period TSm. The configuration of the second embodiment can be combined with the configurations of embodiments and modifications described later. 
     Third Embodiment 
       FIG. 13  is a diagram for explaining the coupling configuration of a plurality of drive electrodes according to a third embodiment. As illustrated in  FIG. 13 , a detecting device  100 B of the third embodiment includes a plurality of second switch elements SW 2   a  and SW 2   b  and a plurality of wires  23   a  and  23   b . The second switch elements SW 2   a  and SW 2   b  and the wires  23   a  and  23   b  are coupled to the left ends and the right ends of the drive electrodes Tx. More specifically, the second switch elements SW 2   a  and the wires  23   a  are coupled to the left ends of the respective drive electrodes Tx. The second switch elements SW 2   b  and the wires  23   b  are coupled to the right ends of the respective drive electrodes Tx. First ends of the second switch elements SW 2   b  are coupled to the right ends of the respective drive electrodes Tx, and second ends of the second switch elements SW 2   b  are coupled to the common wire  23   b . The second switch elements SW 2   a  coupled to the left ends of the respective drive electrodes Tx and the second switch elements SW 2   b  coupled to the right ends of the respective drive electrodes Tx are synchronously switched between tuned on and off. 
     Two second switch elements SW 2   a  and SW 2   b  are coupled to one drive electrode Tx. This configuration can reduce the total resistance of the second switch elements SW 2   a  and SW 2   b  compared with the first and the second embodiments described above. If the period is switched from the first period TSp to the second period TSi, for example, when the drive electrodes Tx- 1  and Tx- 3  supplied with the first voltage signals VH and the drive electrodes Tx- 2  and Tx- 4  supplied with the second voltage signals VL are coupled, electric charges move at both ends of the drive electrodes Tx. Consequently, the present embodiment can shorten the time required for transition from the first voltage signal VH to the intermediate potential VI or transition from the second voltage signal VL to the intermediate potential VI. 
     First Modification of the Third Embodiment 
       FIG. 14  is a diagram for explaining the coupling configuration of a plurality of drive electrodes according to a first modification of the third embodiment. While two second switch elements SW 2   a  and SW 2   b  in the third embodiment describe above are coupled to both ends of each drive electrode Tx, the present embodiment is not limited thereto. In a detecting device  100 C according to the first modification of the third embodiment, the second switch elements SW 2   b  are each provided between two drive electrodes Tx disposed side by side as illustrated in  FIG. 14 . 
     The following describes the coupling configuration of the drive electrodes Tx- 1  and Tx- 2  out of the drive electrodes Tx, for example. The left ends of the drive electrodes Tx- 1  and Tx- 2  are coupled to the respective second switch elements SW 2   a  and the wire  23   a . At the right ends of the drive electrodes Tx- 1  and Tx- 2 , a first end of the second switch element SW 2   b  is coupled to the drive electrode Tx- 1  through a contact portion CH, and a second end of the second switch element SW 2   b  is coupled to the drive electrode Tx- 2  through a contact portion CH. 
     As described above, the second switches SW 2   a  and SW 2   b  of the detecting device  100 C can be coupled to any desired positions. The detecting device  100 C can suppress an increase in the number of wires in the frame region GA compared with the third embodiment described above in the configuration where a plurality of second switch elements SW 2   a  and SW 2   b  are coupled to one drive electrode Tx. The detecting device  100 C does not necessarily have the configuration where two second switch elements SW 2   a  and SW 2   b  are provided to one drive electrode Tx, and three or more second switch elements may be provided. 
     Second Modification of the Third Embodiment 
       FIG. 15  is a diagram for explaining the coupling configuration of a plurality of drive electrodes according to a second modification of the third embodiment. In a detecting device  100 D according to the second modification of the third embodiment, the second switch elements SW 2   a  provided at the left ends of the drive electrodes Tx are each provided between two drive electrodes Tx disposed side by side as illustrated in  FIG. 15 . 
     More specifically, the following describes the coupling configuration of the drive electrodes Tx- 1  and Tx- 2 . At the left ends of the drive electrodes Tx- 1  and Tx- 2 , a first end of the second switch element SW 2   a  is coupled to the drive electrode Tx- 1  through a contact portion CH, and a second end of the second switch element SW 2   a  is coupled to the drive electrode Tx- 2  through a contact portion CH. In other words, the drive electrode selection circuit  15  is not provided in the frame region GA at the left ends of the drive electrodes Tx. Consequently, the detecting device  100 D can suppress an increase in the number of switch elements and wires in the frame region GA at the left ends of the drive electrodes Tx compared with the embodiments described above. The configuration illustrated in the second modification of the third embodiment is applied to a detecting device  100 H (refer to  FIG. 22 ) of a sixth embodiment, which will be described later. 
     Fourth Embodiment 
       FIG. 16  is a diagram for explaining the coupling configuration of a plurality of drive electrodes according to a fourth embodiment in the first period.  FIG. 17  is a diagram for explaining the coupling configuration of the drive electrodes according to the fourth embodiment in the second period. 
     In a detecting device  100 E according to the fourth embodiment, the first switch elements SW 1 H and SW 1 L and the wiring  21  and  22  are provided to both the left ends and the right ends of the drive electrodes Tx as illustrated in  FIGS. 16 and 17 . The first switch elements SW 1 H and SW 1 L at the left ends of the drive electrodes Tx and the first switch elements SW 1 H and SW 1 L at the right ends of the drive electrodes Tx are controlled so as to be synchronously switched between turned on and off. 
     With this configuration, the drive signal supply circuit  20  (refer to  FIG. 6 ) is coupled to the left ends and the right ends of the drive electrodes Tx through the first switch elements SW 1 H and SW 1 L and the wiring  21  and  22 . Thus, the drive signal supply circuit  20  (refer to  FIG. 6 ) supplies the drive signals VTP to the first ends (left ends) and the second ends (right ends) of the drive electrodes Tx in the extending direction. Consequently, the detecting device  100 E can shorten the time required for transition between the first voltage signal VH, the intermediate potential VI, and the second voltage signal VL compared with the embodiments described above. 
     Two second switch elements SW 2   a  and SW 2   b  are provided to one drive electrode Tx. The second switch elements SW 2   a  and SW 2   b  are each provided between two drive electrodes Tx disposed side by side in the first direction Dx at the left end and the right end of the drive electrode Tx. The configuration is not limited thereto, and the second switch elements SW 2   a  and SW 2   b  may employ a configuration in which both ends of one corresponding drive electrode Tx are coupled to each other like the third embodiment illustrated in  FIG. 13 . 
     The detecting device  100 E according to the fourth embodiment performs fingerprint detection by driving part of the drive electrodes Tx (drive electrodes Tx- 3  to Tx- 6  in  FIGS. 16 and 17 ) disposed in an active region AA out of the drive electrodes Tx (drive electrodes Tx- 1  to Tx- 8  in  FIGS. 16 and 17 ). 
     Specifically, as illustrated in  FIG. 16 , the drive signal supply circuit  20  supplies the drive signals VTP having a phase corresponding to the square matrix H to the drive electrodes Tx- 3 , Tx- 4 , Tx- 5 , and Tx- 6  in the active region AA in the first period TSp. In the drive electrodes Tx- 1 , Tx- 2 , Tx- 7 , and Tx- 8  in a region other than the active region AA, all the first switch elements SW 1 H and SW 1 L and the second switch elements SW 2   a  and SW 2   b  are turned off, thereby bringing the drive electrodes Tx- 1 , Tx- 2 , Tx- 7 , and Tx- 8  into a floating state. The drive electrodes Tx in a region other than the active region AA is not necessarily in a floating state and may be coupled to a predetermined reference potential (e.g., the ground potential). 
     Next, as illustrated in  FIG. 17 , all the first switch elements SW 1 H and SW 1 L are turned off in the second period TSi, and the drive electrodes Tx in the active region AA are decoupled from the drive signal supply circuit  20 . In the second period TSi, the second switch elements SW 2   a  and SW 2   b  that couple the drive electrodes Tx in the active region AA are turned on, and the drive electrodes Tx- 3 , Tx- 4 , Tx- 5 , and Tx- 6  in the active region AA are coupled through the second switch elements SW 2   a  and SW 2   b.    
     As a result, the drive electrodes Tx- 3  and Tx- 5  supplied with the first voltage signals VH and the drive electrodes Tx- 4  and Tx- 6  supplied with the second voltage signals VL are coupled in the active region AA. Consequently, the electric potential of the drive electrodes Tx in the active region AA is the intermediate potential VI in the second period TSi. 
     Subsequently, the operations in the third period TSm, the second period TSi, the first period TSp, . . . are repeatedly performed on the drive electrodes Tx in the active region AA. 
     The detecting device  100 E of the fourth embodiment performs CDM drive on only the drive electrodes Tx in the active region AA in the detection region FA. Consequently, the detecting device  100 E can reduce power consumption and shorten the time required to scan the drive electrodes Tx compared with a case where fingerprint detection is performed on the whole detection region FA. 
     The active region AA may be a region specified in advance as a fingerprint detection region, that is, a fixed region. Alternatively, the active region AA may be a region specified based on the position of the finger Fg detected by driving all the drive electrodes Tx in the detection region FA in a time-division manner and performing touch detection (detection of the coordinates of the finger position in the detection region FA). 
     Third Modification of the Fourth Embodiment 
       FIG. 18  is a diagram for explaining the coupling configuration of the drive electrodes according to a third modification of the fourth embodiment. In a detecting device  100 F according to the third modification of the fourth embodiment, the drive electrodes Tx are each divided into a plurality of parts by a slit SL as illustrated in  FIG. 18 . The drive signal supply circuit  20  can independently supply the drive signals VTP to the drive electrodes Tx on the left side of the slits SL and the drive electrodes Tx on the right side of the slits SL. 
     In other words, the first switch elements SW 1 H and SW 1 L and the second switch elements SW 2   a  coupled to the left ends of the drive electrodes Tx, and the first switch elements SW 1 H and SW 1 L and the second switch elements SW 2   b  coupled to the right ends of the drive electrodes Tx are controlled so as to be independently switched between turned on and off. 
     In the example illustrated in  FIG. 18 , fingerprint detection is performed by the aforementioned CDM drive on the drive electrodes Tx- 3 , Tx- 4 , Tx- 5 , and Tx- 6  in an active region AA 2  on the right side of the slits SL out of the drive electrodes Tx- 3 , Tx- 4 , Tx- 5 , and Tx- 6 . In the drive electrodes Tx- 3 , Tx- 4 , Tx- 5 , and Tx- 6  in an active region AA 1  on the left side of the slits SL, all the first switch elements SW 1 H and SW 1 L and the second switch elements SW 2   a  are turned off, thereby brining the drive electrodes Tx- 3 , Tx- 4 , Tx- 5 , and Tx- 6  into a floating state. In this case, the detection electrodes Rx- 3  and Rx- 4  overlapping the active region AA 2  output the detection signals Vdet. The detection electrodes Rx- 1  and Rx- 2  overlapping the active region AA 1  does not output the detection signals Vdet. 
     The detecting device  100 F according to the third modification of the fourth embodiment can make the area of the active region AA 2  on which CDM drive is performed smaller than that of the fourth embodiment described above. In the detecting device  100 F, the area of the drive electrode Tx supplied with the drive signals VTP is smaller (the length in the second direction Dy is shorter) than that of the fourth embodiment. Consequently, the detecting device  100 F can suppress an increase in the time required for transition between the first voltage signal VH, the intermediate potential VI, and the second voltage signal VL. 
     Fifth Embodiment 
       FIG. 19  is a plan view illustrating an example of the configuration of the detecting device according to a fifth embodiment. As illustrated in  FIG. 19 , a detecting device  100 G according to the fifth embodiment further includes a touch detection electrode TE in addition to the drive electrodes Tx and the detection electrodes Rx. The touch detection electrode TE is provided in a frame shape surrounding the drive electrodes Tx and the detection electrodes Rx. The drive electrodes Tx and the detection electrodes Rx are provided in a detection region FA 1 . The touch detection electrode TE is provided in a detection region FA 2  outside the detection region FA 1  (on the outer periphery of the substrate  101 ). 
     The touch detection electrode TE can detect contact or proximity of the finger Fg with or to the detection regions FA 1  and FA 2  by self-capacitive system touch detection, for example. The touch detection electrode TE may be directly coupled to the detection IC (not illustrated) not through the drive electrode selection circuit  15  or the detection electrode selection circuit  14 . Alternatively, the drive electrode selection circuit  15  and the detection electrode selection circuit  14  may also be used for touch detection performed by the touch detection electrode TE. The touch detection electrode TE does not necessarily have one continuous frame shape and may be divided into a plurality of parts and disposed in the detection region FA 2 . 
     When a user brings the finger Fg closer to the detection region FA 1  to perform fingerprint detection, at least part of the finger Fg overlaps (abuts on) the detection region FA 2 . The detecting device  100 G according to the present embodiment has such a size with respect to the finger Fg of the user. With the touch detection electrode TE, the detecting device  100 G substantially need not perform fingerprint detection drive except when the touch detection electrode TE detects a touch. Consequently, the configuration according to the present embodiment performs normal fingerprint detection drive in a touch detection period, while, in a period other than the touch detection period, the configuration does not perform fingerprint detection drive as an idling mode or intermittently performs fingerprint detection drive in a cycle much longer than that of fingerprint detection drive in the touch detection period. 
       FIG. 20  is a diagram for explaining a method for driving the detecting device according to the fifth embodiment. As illustrated in  FIG. 20 , the detecting device  100 G has a fingerprint detection mode (normal detection mode) and an idling mode. In the fingerprint detection mode, the detection controller  11  (refer to  FIG. 4 ) performs the CDM drive described above on the drive electrodes Tx and the detection electrodes Rx to detect a fingerprint of the finger Fg. If no fingerprint is detected in a predetermined period of time (time t 21 ), the detection controller  11  stops CDM drive and shifts to the idling mode. 
     In the idling mode, the detecting device  100 G does not detect a fingerprint of the finger Fg. Specifically, in the idling mode, the detection controller  11  supplies drive signals VID to the touch detection electrode TE in a predetermined cycle to detect a touch, that is, contact or proximity of the finger Fg. The cycle of a touch detection period TSf for performing touch detection is set longer than the cycle of detection in the fingerprint detection mode. 
     In the idling mode, the detection controller  11  performs the CDM drive described above on the drive electrodes Tx and the detection electrodes Rx in a predetermined cycle. As a result, the detection controller  11  acquires base line signals for fingerprint detection in a state where the finger Fg is not present. The detection controller  11  compares the newly acquired base line signals with the conventional base line signals. If these base line signals are different, the detection controller  11  updates the base line signals with the newly acquired base line signals. 
     If contact or proximity of the finger Fg is detected in the touch detection period TSf (time t 22 ), the detection controller  11  shifts from the idling mode to the fingerprint detection mode. 
     The present embodiment performs the same drive on the drive electrodes Tx and the detection electrodes Rx in the detection region FA 1  in the fingerprint detection mode and the idling mode. The present embodiment repeatedly performs the operations in the first period TSp, the second period TSi, the third period TSm, the second period TSi, the first period TSp, . . . as described above. 
     While  FIG. 20  illustrates a case where the detecting device  100 G alternately performs touch detection (touch detection period TSf) by the touch detection electrodes TE and acquisition of the base line signals by the drive electrodes Tx and the detection electrodes Rx in the idling mode, the present embodiment is not limited thereto. In the period of the idling mode, for example, the detecting device  100 G simply needs to acquire the base line signals by the drive electrodes Tx and the detection electrodes Rx at least once. After acquiring the base line signals, the detecting device  100 G may repeatedly perform touch detection by the touch detection electrode TE in a plurality of predetermined cycles. 
     Fourth Modification of the Fifth Embodiment 
       FIG. 21  is a diagram for explaining the method for driving the detecting device according to a fourth modification of the fifth embodiment. As illustrated in  FIG. 21 , the detecting device  100 G according to the fourth modification of the fifth embodiment is different from the aforementioned fifth embodiment in the operations in the fingerprint detection mode (normal detection mode). 
     Specifically, the fingerprint detection mode has no second period TSi, and the first periods TSp and the third periods TSm are repeatedly arranged. In other words, in the fingerprint detection mode, the detecting device  100 G does not perform the operation in the second period TSi and alternately supplies the first voltage signals VH and the second voltage signals VL to the drive electrodes Tx not through the intermediate potential VI based on the predetermined code (square matrix H). In the idling mode, the detecting device  100 G repeatedly performs the operations in the first period TSp, the second period TSi, the third period TSm, the second period TSi, the first period TSp, . . . as described above. In other words, in the idling mode, the detecting device  100 G alternately supplies the first voltage signals VH and the second voltage signals VL to the drive electrodes Tx through the intermediate potential VI based on the predetermined code (square matrix H). 
     The fourth modification can increase the speed of scanning the drive electrodes Tx in the fingerprint detection mode and shorten the time required for fingerprint detection. By contrast, the fourth modification performs the drive for reducing power consumption described above in the idling mode having less restriction on the scanning speed. As described above, the detecting device  100 G can switch the system of CDM drive on the drive electrodes Tx depending on the required characteristics (increase in scanning speed or reduction in power consumption). 
     While the fourth modification describes the example that switches the system of CDM drive on the drive electrodes Tx between the fingerprint detection mode and the idling mode in  FIG. 21 , the present modification is not limited thereto. The fourth modification, for example, may switch the system of CDM drive between fingerprint detection on the whole detection region FA and fingerprint detection on the partial active region AA. Alternatively, the fourth modification may switch the system of CDM drive based on the detection conditions, such as the resolution of detection. 
     Sixth Embodiment 
       FIG. 22  is a plan view of an example of the configuration of the detecting device according to a sixth embodiment. A detecting device  100 H of the sixth embodiment is different from the first to the fifth embodiments described above in the arrangement relation of the drive electrodes Tx and the detection electrodes Rx with the peripheral circuits and the wiring substrate  76 . Specifically, as illustrated in  FIG. 22 , the drive electrode selection circuit  15  and the drive electrodes Tx are disposed side by side in the second direction Dy in which the drive electrodes Tx extend. The wiring substrate  76  is coupled to the side of the frame region GA provided with the drive electrode selection circuit  15 . A plurality of detection electrode selection circuits  14  are disposed in a manner sandwiching the drive electrodes Tx in the first direction Dx. 
     The drive electrode selection circuit  15  includes a shift register circuit  151  and a buffer circuit  152 . The shift register circuit  151  selects a plurality of drive electrodes Tx based on a predetermined code. The buffer circuit  152  amplifies the drive signals VTP and supplies them to the selected drive electrodes Tx. A plurality of power supply lines PL supply electric power to the buffer circuit  152  from the outside. The power supply lines PL, for example, supply electric power to both ends and the center part of the buffer circuit  152  in the first direction Dx. The sixth embodiment has little variation in the distance between the drive electrodes Tx and the drive electrode selection circuit  15 . This configuration reduces the difference in resistance between the wires (not illustrated) that couple the drive electrodes Tx and the drive electrode selection circuit  15  and suppresses variation in the voltage of the drive signals VTP. 
     Seventh Embodiment 
       FIG. 23  is a sectional view of a schematic sectional configuration of the detecting device according to a seventh embodiment. As illustrated in  FIG. 23 , a detecting device  100 I according to the seventh embodiment does not include the display panel  30  (refer to  FIG. 2 ) and is provided as the detecting device  100 I alone. The substrate  101 , the drive electrodes Tx, the detection electrodes Rx, and other components of the detecting device  100 I may be made of non-translucent material. The drive electrodes Tx and the detection electrodes Rx, for example, may be made of metal material. This configuration can increase the flexibility in arrangement of the switch elements, such as the second switch elements SW 2 . 
     The detecting device  100 I does not necessarily include the cover member  80 . In this case, the detecting device  100 I may have a configuration in which a protective film (insulating film) that covers the drive electrodes Tx and the detection electrodes Rx is provided instead of the cover member  80 . 
     While exemplary embodiments according to the present disclosure have been described, the embodiments are not intended to limit the disclosure. The contents disclosed in the embodiments are given by way of example only, and various changes may be made without departing from the spirit of the present disclosure. Appropriate modifications made without departing from the spirit of the present disclosure naturally fall within the technical scope of the present disclosure.