Patent Publication Number: US-2023162524-A1

Title: Detection device, display device, detection system, and detection method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Patent Application No. PCT/JP2021/028410 filed on Jul. 30, 2021 which designates the United States, incorporated herein by reference, and which claims the benefit of priority from Japanese Patent Application No. 2020-129655 filed on Jul. 30, 2020, incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a detection device, a display device, a detection system, and a detection method. 
     2. Description of the Related Art 
     In recent years, a detection device so-called a touch panel, which is capable of detecting an external nearby object, is provided with a fingerprint sensor in some cases. For example, a configuration that achieves both touch detection and fingerprint detection through a capacitive scheme has been disclosed (refer to Japanese Patent Application Laid-open Publication No. 2017-192176, for example). In the fingerprint detection, the shape of a fingerprint of a finger contacting a detection device is detected by detecting capacitance change according to concavity-convexity of the fingerprint. Thus, electrodes used for the fingerprint detection have smaller areas than those used for a hand or finger detection. 
     Fingerprint detection used for personal authentication and the like is typically performed at the timing of fingerprint acquisition request from a host device of an apparatus on which a touch sensor is mounted. The host device performs fingerprint acquisition request again depending on a result of the authentication (for example, when the authentication has failed). The authentication is highly likely to fail when a finger is moving (for example, a user is performing swipe operation) at the timing of fingerprint acquisition request from the host device. This leads to authentication ratio decrease and a time loss, and authentication accuracy potentially decreases. 
     The present invention is intended to provide a detection device, a display device, a detection system, and a detection method that can improve authentication accuracy. 
     SUMMARY 
     A detection device according to an embodiment of the present disclosure includes a sensor unit, a detector configured to receive an output from a sensor, a detection controller configured to drive and control the sensor unit and the detector, and a processor configured to perform processing in accordance with an output from the detector. The detection controller drives the sensor unit and the detector and determines a touch detection duration in which a coordinate of a finger contacting or nearby the sensor unit is detected, and a fingerprint detection duration in which a fingerprint image of the finger is detected, the detector alternately executes detection of the coordinate of the finger in the touch detection duration and detection of the fingerprint image in the fingerprint detection duration, and the processor sequentially acquires the coordinate of the finger and the fingerprint image from the detector, calculates a difference value between the coordinates of the finger that are detected in the touch detection durations before and after the fingerprint detection duration in which each fingerprint image is acquired, holds the acquired fingerprint image when the difference value is equal to or smaller than a predetermined value, and discards the acquired fingerprint image when the difference value is larger than the predetermined value. 
     A display device according to an embodiment of the present disclosure includes the detection device above, and a display panel provided with a display region for displaying an image, the display region overlapping a detection region of the detection device. 
     A detection system according to an embodiment of the present disclosure includes a detection device configured to determine a touch detection duration in which a coordinate of a finger contacting or nearby a sensor unit is detected and a fingerprint detection duration in which a fingerprint of the finger is detected, and a control circuit configured to perform processing in accordance with an output from the detection device. The detection device alternately determines the touch detection durations and the fingerprint detection durations, and the control circuit acquires a fingerprint image in each fingerprint detection duration, calculates a difference value between the coordinates of the finger detected in the touch detection durations before and after the fingerprint detection duration in which the fingerprint image is acquired, holds the acquired fingerprint image when the difference value is equal to or smaller than a predetermined value, and discards the acquired fingerprint image when the difference value is larger than the predetermined value. 
     A detection method according to an embodiment in which a touch detection duration in which a coordinate of a finger contacting or nearby a sensor unit is detected and a fingerprint detection duration in which a fingerprint of the finger is detected are alternately provided is disclosed. The detection method includes acquiring a fingerprint image in the fingerprint detection duration, calculating a difference value between the coordinates of the finger detected in the touch detection durations before and after the fingerprint detection duration in which the fingerprint image is acquired, holding the acquired fingerprint image when the difference value is equal to or smaller than a predetermined value, and discarding the acquired fingerprint image when the difference value is larger than the predetermined value. 
     A detection device according to an embodiment of the present disclosure includes a sensor unit, a detector configured to receive an output from a sensor, a detection controller configured to drive and control the sensor unit and the detector, and a processor configured to perform processing in accordance with an output from the detector. The detection controller drives the sensor unit and the detector and determines a coordinate detection duration in which a coordinate of a detection target body contacting or nearby the sensor unit is detected, and a surface information detection duration in which a concavity-convexity pattern on the surface of the detection target body is detected, the detector alternately executes detection of the coordinate of the detection target body in the coordinate detection duration and detection of the concavity-convexity pattern in the surface information detection duration, and the processor acquires the coordinate of the detection target body and the concavity-convexity pattern from the detector, calculates a difference value between the coordinates of the detection target body detected in the coordinate detection durations before and after the surface information detection duration in which the concavity-convexity pattern is acquired, holds the acquired concavity-convexity pattern when the difference value is equal to or smaller than a predetermined value, and discards the acquired concavity-convexity pattern when the difference value is larger than the predetermined value. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a plan view of a display device including a detection device according to an embodiment; 
         FIG.  2    is a sectional view taken along line II-II′ in  FIG.  1   ; 
         FIG.  3    is a plan view illustrating the detection system according to the embodiment; 
         FIG.  4    is a block diagram illustrating an exemplary configuration of the detection system according to a first embodiment; 
         FIG.  5    is an explanatory diagram for description of the fundamental principle of mutual capacitive touch detection; 
         FIG.  6    is a plan view of the detection device according to the first embodiment; 
         FIG.  7    is a plan view illustrating part of first electrodes and second electrodes in an enlarged manner; 
         FIG.  8    is a sectional view taken along line VII-VII′ in  FIG.  7   ; 
         FIG.  9    is a timing chart illustrating exemplary operation of switching between a first duration and a second duration; 
         FIG.  10    is a diagram illustrating an exemplary first detection mode for executing touch detection in a touch detection duration; 
         FIG.  11    is a diagram illustrating an exemplary second detection mode for executing fingerprint detection in a fingerprint detection duration; 
         FIG.  12    is a diagram illustrating an exemplary third detection mode for executing fingerprint detection in a fingerprint detection duration; 
         FIG.  13    is a diagram illustrating an exemplary fourth detection mode for repeatedly executing touch detection and fingerprint detection; 
         FIG.  14 A  is a flowchart illustrating exemplary authentication data acquisition processing at a processor of the detection device according to the first embodiment; 
         FIG.  14 B  is a diagram illustrating a modification of the authentication data acquisition processing illustrated in  FIG.  14 A ; 
         FIG.  15    is a flowchart illustrating exemplary authentication processing at the processor of the detection device according to the first embodiment; 
         FIG.  16    is a block diagram illustrating an exemplary configuration of a detection system according to a second embodiment; 
         FIG.  17    is a sequence diagram illustrating a specific example of the authentication data acquisition processing in the detection system according to the second embodiment; 
         FIG.  18    is a sequence diagram illustrating a specific example of the authentication processing in the detection system according to the second embodiment; and 
         FIG.  19    is a block diagram illustrating an exemplary configuration of a detection system according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects (embodiments) of the present invention will be described below in detail with reference to the accompanying drawings. Contents described below in the embodiments do not limit the present invention. Components described below include those that could be easily thought of by the skilled person in the art and those identical in effect. Components described below may be combined as appropriate. What is disclosed herein is merely exemplary, and any modification that could be easily thought of by the skilled person in the art as appropriate without departing from the gist of the invention is contained in the scope of the present invention. For clearer description, the drawings are schematically illustrated for the width, thickness, shape, and the like of each component as compared to an actual aspect in some cases, but the drawings are merely exemplary and do not limit interpretation of the present invention. In the present specification and drawings, any element same as that already described with reference to an already described drawing is denoted by the same reference sign, and detailed description thereof is omitted as appropriate in some cases. 
       FIG.  1    is a plan view of a display device including a detection device according to an embodiment.  FIG.  2    is a sectional view taken along line II-II′ in  FIG.  1   . As illustrated in  FIGS.  1  and  2   , this display device  100  of the present embodiment includes a display region AA, a frame region GA, and a detection region FA. The display region AA is a region in which an image on a display panel  30  is displayed. The frame region GA is a region outside the display region AA. The detection region FA is a region in which concavity-convexity of the surface of a contacting or nearby finger or the like is detected. The detection region FA is provided over the entire display region AA. 
     As illustrated in  FIG.  2   , the display device  100  of the present embodiment includes a cover member  101 , a detection device  1 , and the display panel  30 . The cover member  101  is a plate member having a first surface  101   a  and a second surface  101   b  opposite the first surface  101   a . The first surface  101   a  of the cover member  101  is a detection surface of the detection device  1 , and when a detection target body contacts the detection surface, the two-dimensional coordinate position of the detection target body on the detection surface and concavity-convexity of the surface of the detection target body are detected. In the present embodiment, the detection target body is a finger of a user, and the concavity-convexity of the surface of the detection target body includes a fingerprint. Although the detection target body is a finger in the following description, the detection target body may be another site on the body of the user, such as a palm or a sole in place of a finger. In this case, the surface concavity-convexity (concavity-convexity pattern) is a dermatoglyphic pattern of the other site, such as a palm print, a sole print, or a toe print. 
     The first surface  101   a  of the cover member  101  is a display surface on which an image on the display panel  30  is displayed, and also serves as an observation surface on which the user observes the image. The display panel  30  and a sensor unit  10  of the detection device  1  are provided to the second surface  101   b  side of the cover member  101 . The cover member  101  is a member for protecting the sensor unit  10  and the display panel  30  and provided over the sensor unit  10  and the display panel  30 . The cover member  101  is, for example, a glass substrate or a resin substrate. 
     The cover member  101 , the sensor unit  10 , and the display panel  30  are not limited to a rectangular shape in a plan view but may have a circular shape, an oval shape, or a deformed shape of each of these outer shapes, part of which is omitted. Alternatively, the outer shape of the cover member  101  may be different from the outer shapes of the sensor unit  10  and the display panel  30  as in a case, for example, where the cover member  101  has a circular shape and the sensor unit  10  and the display panel  30  have a regular polygonal shape. The cover member  101  is not limited to a flat plate shape but may have a curved display configuration with a curved surface in which, for example, the display region AA has a curved surface or the frame region GA is curved toward the display panel  30  side. 
     As illustrated in  FIGS.  1  and  2   , a decorative layer  110  is provided on the second surface  101   b  of the cover member  101  in the frame region GA. The decorative layer  110  is a coloring layer having a smaller light transmittance than that of the cover member  101 . The decorative layer  110  can prevent wires, circuits, and the like superimposed on the frame region GA from being visually recognized by a viewer. The decorative layer  110  is provided on the second surface  101   b  in the example illustrated in  FIG.  2    but may be provided on the first surface  101   a . The decorative layer  110  is not limited to a single layer but may be a stack of a plurality of layers. 
     The detection device  1  includes the sensor unit  10  configured to detect concavity-convexity of the surface of a finger Fin or the like contacting or nearby the first surface  101   a  of the cover member  101 . As illustrated in  FIG.  2   , the sensor unit  10  of the detection device  1  is provided on the display panel  30 . In other words, the sensor unit  10  is provided between the cover member  101  and the display panel  30  and overlaps the display panel  30  when viewed in a direction orthogonal to the first surface  101   a . The sensor unit  10  is coupled to a flexible printed board  76  through which a detection signal from the sensor unit  10  can be output to the outside. 
     One surface of the sensor unit  10  is bonded to the cover member  101  with a bonding layer  71  interposed therebetween. The other surface of the sensor unit  10  is bonded to a polarization plate  35  of the display panel  30  with a bonding layer  72  interposed therebetween. The bonding layer  71  is, for example, optical clear resin (OCR; or liquid optically clear adhesive (LOCA)) that is liquid UV curable resin. The bonding layer  72  is, for example, optical clear adhesive (OCA). 
     The display panel  30  includes a first substrate  31 , a second substrate  32 , a polarization plate  34  provided on the lower side of the first substrate  31 , and the polarization plate  35  provided on the upper side of the second substrate  32 . The first substrate  31  is coupled to a flexible printed board  75 . Liquid crystal display elements as a display functional layer are provided between the first substrate  31  and the second substrate  32 . In other words, the display panel  30  is a liquid crystal panel. The display panel  30  is not limited thereto but may be, for example, an organic EL display panel (organic light emitting diode (OLED)) or an inorganic EL display (micro LED or mini LED). Alternatively, the display panel may be a liquid crystal display (LCD) panel using liquid crystal elements as display elements, or an electrophoretic display (EPD) panel using electrophoretic elements as display elements. 
     As illustrated in  FIG.  2   , the sensor unit  10  is disposed at a position closer to the cover member  101  than the display panel  30  in a direction orthogonal to the second surface  101   b  of the cover member  101 . Thus, the distance between a fingerprint detection electrode and the first surface  101   a  as the detection surface can be reduced as compared to a case in which, for example, the fingerprint detection electrode is provided integrally with the display panel  30 . Accordingly, the display device  100  including the detection device  1  of the present embodiment can have improved detection performance. 
     The display device  100  has a configuration of what is called an out-cell scheme in which the sensor unit  10  and the display panel  30  are independent from each other, but may have a configuration of what is called an in-cell scheme or an on-cell scheme in which some substrates or electrodes are shared between the sensor unit  10  and the display panel  30 . 
       FIG.  3    is a plan view illustrating a detection system according to the embodiment. As illustrated in  FIG.  3   , this detection system  2  includes a substrate  3 , a wiring substrate  4 , and a control board  5 . The substrate  3  is electrically coupled to the control board  5  through the wiring substrate  4 . 
     The substrate  3  has the detection region AA and the peripheral region GA described above. The sensor unit  10  is provided in the detection region AA. A first electrode selection circuit  15  and a detection electrode selection circuit  16  are provided in the peripheral region GA. 
     A detection circuit  6  is provided on the wiring substrate  4 . The detection circuit  6  is, for example, a detection IC. 
     A control circuit  7  is provided on the control board  5 . The control circuit  7  is, for example, a host IC configured as a field programmable gate array (FPGA). The control circuit  7  supplies control signals to the sensor unit  10 , the first electrode selection circuit  15 , the detection electrode selection circuit  16 , and the detection circuit  6  and controls detection operation of the sensor unit  10 . One or both of the first electrode selection circuit  15  and the detection electrode selection circuit  16  may be provided in the detection circuit  6  or the control circuit  7 . 
     The first electrode selection circuit  15  is provided in a region extending in a second direction Dy in the peripheral region GA. The detection electrode selection circuit  16  is provided in a region extending in a first direction Dx in the peripheral region GA and provided between the sensor unit  10  and the detection circuit  6 . 
     In the present embodiment, the detection device  1  includes the sensor unit  10 , the first electrode selection circuit  15 , the detection electrode selection circuit  16 , and the detection circuit  6 . The detection system  2  includes the detection device  1  and the control circuit  7 . 
     The first direction Dx is an in-plane direction parallel to the substrate  3 . The second direction Dy is an in-plane direction parallel to the substrate  3  and orthogonal to the first direction Dx. The second direction Dy may intersect the first direction Dx instead of being orthogonal. A third direction Dz is a direction orthogonal to the first direction Dx and the second direction Dy and is the normal direction of the substrate  3 . 
     First Embodiment 
     The following describes a detailed configuration of the detection device  1 .  FIG.  4    is a block diagram illustrating an exemplary configuration of a detection system according to a first embodiment. As illustrated in  FIG.  4   , the detection system  2  includes the detection device  1  and the control circuit  7  as a host device of the detection device  1 . The detection device  1  includes the sensor unit  10 , a detection controller  11 , the first electrode selection circuit  15 , the detection electrode selection circuit  16 , a detector  40 , and a processor  50 . In the present embodiment, the control circuit  7  illustrated in  FIG.  3    includes the detection controller  11 . In the present embodiment, the detection circuit  6  illustrated in  FIG.  3    includes the detector  40  and the processor  50 . 
     The sensor unit  10  performs detection in accordance with a second drive signal Vtx 2  supplied from the first electrode selection circuit  15 . Specifically, a plurality of first electrodes Tx (refer to  FIG.  6   ) are individually or simultaneously selected through operation of the first electrode selection circuit  15 . Then, the first electrode selection circuit  15  supplies the second drive signal Vtx 2  having a phase determined based on a predetermined sign to each of the selected first electrodes Tx. The sensor unit  10  converts change in concavity-convexity of the surface of the contacting or nearby finger Fin or hand into change in an electric signal based on the principle of mutual capacitive detection and outputs the electric signal to the detection circuit  6 . 
     The sensor unit  10  can also detect the position (coordinate) of the contacting or nearby finger Fin or the like in accordance with a first drive signal Vtx 1  supplied from the first electrode selection circuit  15 . The sensor unit  10  performs detection over the entire detection region FA by scanning the first electrodes Tx for each first electrode block including a plurality of first electrodes Tx or for each one in a plurality of first electrodes Tx. The sensor unit  10  outputs change in an electric signal due to existence of the finger Fin contacting the detection surface to the detection circuit  6  based on the principle of mutual capacitive detection. The above-described touch detection on the detection surface in accordance with the first drive signal Vtx 1  only requires detection and specification of the coordinate of the finger and thus has a detection resolution lower than the detection in accordance with the second drive signal Vtx 2  does. 
     The detection controller  11  is a circuit configured to control operation of the first electrode selection circuit  15 , the detection electrode selection circuit  16 , and the detector  40  by supplying a control signal to each of the components. The detection controller  11  includes a drive unit  11   a  and a clock signal output unit  11   b . The drive unit  11   a  supplies power voltage Vdd to the first electrode selection circuit  15 . The detection controller  11  supplies various kinds of control signals Vctr 1  to the first electrode selection circuit  15  based on a clock signal from the clock signal output unit  11   b.    
     The first electrode selection circuit  15  is a circuit configured to simultaneously or individually select a plurality of first electrodes Tx based on various kinds of the control signals Vctr 1 . The first electrode selection circuit  15  supplies the first drive signal Vtx 1  or the second drive signal Vtx 2  to the plurality of selected first electrodes Tx based on the various kinds of control signals Vctr 1  and the power voltage Vdd. The first drive signal Vtx 1  and the second drive signal Vtx 2  include not only those having mutually different waveforms including wavelengths and amplitudes but also those having the same waveform and output to the sensor unit  10  in mutually different durations. The sensor unit  10  can achieve a plurality of detection modes of a first detection mode M 1 , a second detection mode M 2 , a third detection mode M 3 , and a fourth detection mode M 4  (refer to  FIGS.  10  to  13   ) by differentiating the state of selection of first electrodes Tx by the first electrode selection circuit  15 . 
     The detection electrode selection circuit  16  is a switch circuit configured to simultaneously select a plurality of second electrodes Rx (refer to  FIG.  6   ). The detection electrode selection circuit  16  selects a plurality of second electrodes Rx based on a second electrode selection signal Vhse 1  supplied from the detection controller  11  and couples the plurality of second electrodes Rx and the detection circuit  6 . 
     The detector  40  is a circuit configured to detect existence of a touch of the finger on the detection surface at a relatively large pitch based on a control signal supplied from the detection controller  11  and a first detection signal Vdet 1  and a second detection signal Vdet 2  supplied from the sensor unit  10  and detect a fingerprint of the finger at a relatively minute pitch. The detector  40  includes a detection signal amplifier  42 , an A/D converter  43 , a signal processor  44 , a coordinate extractor  45 , a fingerprint image generator  46 , a detection timing controller  47 , a first storage  48 , and a detection data generator  49 . 
     The detection timing controller  47  controls the detection signal amplifier  42 , the A/D converter  43 , the signal processor  44 , the coordinate extractor  45 , the fingerprint image generator  46 , and the detection data generator  49  based on a control signal supplied from the detection controller  11  so that these components operate in synchronization. The first detection signal Vdet 1  and the second detection signal Vdet 2  are simply referred to as a detection signal Vdet when not needed to be distinguished from each other in the following description. 
     The first storage  48  may be, for example, a random access memory (RAM), a read only memory (ROM), or a register circuit. In the present embodiment, the first storage  48  stores, as buffering data, a touch detection coordinate acquired by the coordinate extractor  45  and a fingerprint image generated by the fingerprint image generator  46 . 
     The sensor unit  10  supplies the first detection signal Vdet 1  and the second detection signal Vdet 2  to the detection signal amplifier  42 . The detection signal amplifier  42  amplifies the first detection signal Vdet 1  and the second detection signal Vdet 2 . The A/D converter  43  converts an analog signal output from the detection signal amplifier  42  into a digital signal. 
     The signal processor  44  performs predetermined decoding processing based on an output signal from the A/D converter  43 . Specifically, the signal processor  44  performs processing of extracting a differential signal (absolute value |ΔV|) of the detection signal Vdet. The signal processor  44  performs determination based on comparison of the absolute value |ΔV| with a predetermined threshold voltage and outputs a result of the determination. 
     The coordinate extractor  45  calculates a touch panel coordinate based on the determination result from the signal processor  44  and stores the obtained touch panel coordinate as buffering data in the first storage  48 . 
     The fingerprint image generator  46  generates a fingerprint image based on the determination result from the signal processor  44  and stores the obtained fingerprint image in the first storage  48  as buffering data. The present disclosure is not limited by this fingerprint image generation method. 
     The coordinate extraction circuit  45  may generate a fingerprint image of the finger Fin in place of the above-described fingerprint image generator  46 . In this case, the coordinate position and generation of a fingerprint image can be formed by the coordinate extraction circuit alone, and the fingerprint image generator is unnecessary. 
     The detection data generator  49  combines the pieces of buffering data stored in the first storage  48  and outputs the combination as a sensor output Vo. 
     The detection device  1  detects the finger Fin contacting the detection surface of the sensor unit  10  based on the principle of capacitive detection (hereinafter referred to as “touch detection”). The detection device  1  also detects a fingerprint by detecting concavity-convexity of the surface of the finger Fin contacting the sensor unit  10  based on the principle of capacitive detection (hereinafter referred to as “fingerprint detection”). 
     In capacitive touch detection operation, a state in which capacitance change has occurred due to contact with the finger Fin is referred to as a “touched state” below. In addition, a state in which no capacitance change has occurred due to the finger Fin is referred to as a “non-touched state” below. 
     The following describes the fundamental principle of mutual capacitive touch detection by the detection device  1  of the present embodiment with reference to  FIG.  5   .  FIG.  5    is an explanatory diagram for description of the fundamental principle of mutual capacitive touch detection.  FIG.  5    also illustrates the detection circuit. 
     As illustrated in  FIG.  5   , a capacitor element C 1  includes a pair of a drive electrode E 1  and a detection electrode E 2  disposed opposite each other with a dielectric D interposed therebetween. An electric field extending from end parts of the drive electrode E 1  toward the upper surface of the detection electrode E 2  in addition to an electric field (not illustrated) formed between facing surfaces of the drive electrode E 1  and the detection electrode E 2  occurs to the capacitor element C 1 . One end of the capacitor element C 1  is coupled to an alternating-current signal source (drive signal source), and the other end thereof is coupled to a voltage detector DET. The voltage detector DET is, for example, an integration circuit included in the detector  40  illustrated in  FIG.  4   . 
     An alternating-current square wave Sg having a predetermined frequency (for example, several kHz to several hundreds kHz approximately) is applied from the alternating-current signal source to the drive electrode E 1  (one end of the capacitor element C 1 ). Current in accordance with the capacitance value of the capacitor element C 1  flows to the voltage detector DET. The voltage detector DET converts current variation in accordance with the alternating-current square wave Sg into voltage variation. 
     As a capacitor C 2  formed by the finger contacts the detection electrode E 2  or becomes nearby the detection electrode E 2  to such an extent that it can be regarded that the capacitor C 2  contacts the detection electrode E 2 , fringe electrical lines of force between the drive electrode E 1  and the detection electrode E 2  are interrupted by the conductor (finger). Accordingly, the capacitor element C 1  acts as a capacitor element having a further smaller capacitance value in accordance with approaching than a capacitance value in the non-contact state. 
     The amplitude of a voltage signal output from the voltage detector DET decreases as compared to the non-contact state as the finger Fin approaches the contact state. The absolute value |ΔV| of this voltage difference changes in accordance with influence of the finger Fin contacting the detection surface. The detector  40  determines whether the finger Fin is contacting the detection surface by comparing the absolute value |ΔV| with a predetermined threshold voltage. In the present embodiment, the determination is performed by any one of the signal processor  44  and the coordinate extractor  45  of the detector  40  or by both in cooperation. 
     The detector  40  further determines concavity-convexity of the finger Fin or the like based on the absolute value |ΔV|. The concavity-convexity determination may be performed by comparing the absolute value |ΔV| with a predetermined threshold, and the threshold may be different from the threshold for determining whether the finger Fin is contacting/nearby or a plurality of thresholds may be used. In the present embodiment, the determination is performed by any one of the signal processor  44  and the fingerprint image generator  46  of the detector  40  or by both in cooperation. In this manner, the detector  40  can perform touch detection and fingerprint detection based on the fundamental principle of mutual capacitive touch detection. 
     In the present disclosure, a fingerprint image is data formed as surface information based on outputs from the second electrodes Rx and is different from a touch coordinate (point information) with which one or several coordinate positions are specified on the detection surface. More specifically, a fingerprint image is an assembly of pieces of detection data in a plurality of detection unit regions, and each piece of detection data includes, for example, the coordinate of the corresponding detection unit region and a result of concavity-convexity determination at each coordinate position. The concavity-convexity determination may provide such a binary determination result that the surface is determined to be concave when the detection result is larger than a threshold as described above or the surface is determined to be convex when the detection result is smaller than the threshold. Instead, the concavity-convexity determination may provide data obtained by further digitalizing an actual detection signal based on a plurality of thresholds. Two-dimensional surface information is formed through accumulation of these pieces of data for respective coordinates. 
     Although the finger Fin as the detection target body and a fingerprint thereof are detected in the present embodiment, the detection target body is not limited to a finger and the concavity-convexity of the detection target body is not limited to a fingerprint. 
     The following describes the configuration of the first electrodes Tx and the second electrodes Rx of the detection device  1 .  FIG.  6    is a plan view of the detection device according to the first embodiment.  FIG.  7    is a plan view illustrating part of the first electrodes and the second electrodes in an enlarged manner.  FIG.  8    is a sectional view taken along line VII-VII′ in  FIG.  7   . 
     As illustrated in  FIG.  6   , the detection device  1  includes a sensor substrate  21 , the first electrodes Tx and the second electrodes Rx provided on the sensor substrate  21 . The sensor substrate  21  is a translucent glass substrate that can transmit visible light. Alternatively, the sensor substrate  21  may be a translucent resin substrate or film made of resin such as polyimide. The sensor unit  10  is a translucent sensor. 
     The first electrodes Tx extend in the first direction Dx and are arrayed in the second direction Dy. The second electrodes Rx extend in the second direction Dy and are arrayed in the first direction Dx. The second electrodes Rx extend in a direction intersecting the first electrodes Tx in a plan view. Each second electrode Rx is coupled through a frame wire (not illustrated) to the flexible printed board  76  provided on a short side of the frame region GA of the sensor substrate  21 . The first electrodes Tx and the second electrodes Rx are provided in the detection region FA. The first electrodes Tx are made of translucent conductive material such as indium tin oxide (ITO). The second electrodes Rx are made of metallic material such as aluminum or aluminum alloy. The first electrodes Tx may be made of metallic material and the second electrodes Rx may be made of ITO. When the second electrodes Rx are made of metallic material, resistance on the detection signal Vdet can be reduced. 
     The first direction Dx is an in-plane direction parallel to the sensor substrate  21  and is, for example, a direction parallel to a side of the detection region FA. The second direction Dy is an in-plane direction parallel to the sensor substrate  21  and orthogonal to the first direction Dx. The second direction Dy may intersect the first direction Dx instead of being orthogonal. In the present specification, a “plan view” is a view in a direction orthogonal to the sensor substrate  21 . 
     Capacitors are formed at respective intersections of the second electrodes Rx and the first electrodes Tx. When mutual capacitive touch detection operation is performed in the sensor unit  10 , the first electrode selection circuit  15  selects first electrodes Tx and simultaneously supplies the first drive signal Vtx 1  or the second drive signal Vtx 2  to the selected first electrodes Tx. Then, fingerprint detection is performed as the detection signal Vdet in accordance with capacitance change due to concavity-convexity of the surface of a contacting or nearby finger or the like is output from each second electrode Rx. Alternatively, touch detection is performed as the detection signal Vdet in accordance with capacitance change due to a contacting or nearby finger or the like is output from each second electrode Rx. 
     As illustrated in  FIG.  6   , various circuits such as the first electrode selection circuit  15  and the detection electrode selection circuit  16  are provided in the frame region GA of the sensor substrate  21 . The first electrode selection circuit  15  includes a first selection circuit  151 , a second selection circuit  152 , a third selection circuit  153 , and a first electrode block selection circuit  154 . However, this is merely exemplary. At least some of the various circuits may be included in a detection integrated circuit (IC) mounted on the flexible printed board  76 . Alternatively, at least some of the various circuits may be provided on an external control board. The first selection circuit  151 , the second selection circuit  152 , the third selection circuit  153 , and the first electrode block selection circuit  154  are not limited to a configuration in which each of the circuits is provided as an individual circuit. The first electrode selection circuit  15  may be provided as one integrated circuit having functions of the first selection circuit  151 , the second selection circuit  152 , the third selection circuit  153 , and the first electrode block selection circuit  154 . The first electrode selection circuit  15  may be a semiconductor integrated circuit (IC). 
     The following describes the configuration of the first electrodes Tx and the second electrodes Rx. As illustrated in  FIG.  7   , each second electrode Rx is a zigzag line and has a longitudinal direction along the second direction Dy as a whole. For example, each second electrode Rx includes a plurality of first straight parts  26   a , a plurality of second straight parts  26   b , and a plurality of bent parts  26   x . The second straight parts  26   b  extend in a direction intersecting the first straight parts  26   a . Each bent part  26   x  couples a first straight part  26   a  and a second straight part  26   b.    
     The first straight parts  26   a  extend in a direction intersecting the first direction Dx and the second direction Dy. The second straight parts  26   b  extend in another direction intersecting the first direction Dx and the second direction Dy. Each first straight part  26   a  and a corresponding second straight part  26   b  are symmetric with respect to a virtual line (not illustrated) parallel to the first direction Dx. Each second electrode Rx is formed by alternately coupling the first straight parts  26   a  and the second straight parts  26   b  in the second direction Dy. 
     The disposition interval between the bent parts  26   x  of each second electrode Rx in the second direction Dy is represented by Pry. The disposition interval between the bent parts  26   x  of adjacent second electrodes Rx in the first direction Dx is represented by Prx. In the present embodiment, for example, Prx is preferably smaller than Pry. Each second electrode Rx is not limited to a zigzag shape but may have another shape such as a wavy shape or a straight shape. 
     As illustrated in  FIG.  7   , a plurality of first electrodes Tx- 1 , Tx- 2 , Tx- 3 , Tx- 4 , . . . each include a plurality of electrode parts  23   a  and  23   b  and a plurality of coupling parts  24 . In the following description, the first electrodes Tx- 1 , Tx- 2 , Tx- 3 , Tx- 4 , . . . are simply referred to as first electrodes Tx when not needed to be distinguished from each other. 
     The first electrodes Tx- 1  and Tx- 2  intersecting the corresponding second straight parts  26   b  of the second electrodes Rx each include the electrode part  23   a  having two sides parallel to the second straight parts  26   b . The first electrodes Tx- 3  and Tx- 4  intersecting the corresponding first straight parts  26   a  of the second electrodes Rx each include the electrode part  23   b  having two sides parallel to the first straight parts  26   a . In other words, a plurality of electrode parts  23   a  and a plurality of electrode parts  23   b  are disposed along each second electrode Rx. Accordingly, the separation distance between the second electrode Rx in a zigzag shape and each of the electrode parts  23   a  and  23   b  is constant in a plan view. 
     The plurality of electrode parts  23   a  in each of the first electrodes Tx- 1  and Tx- 2  are arranged in the first direction Dx and separated from each other. In each first electrode Tx, each coupling part  24  couples adjacent electrode parts  23   a  among the plurality of electrode parts  23   a . In a plan view, each second electrode Rx passes between adjacent electrode parts  23   a  and intersects coupling parts  24 . The first electrodes Tx- 3  and Tx- 4  have the same configuration. Each second electrode Rx is a metal thin line, and the width of the second electrode Rx in the first direction Dx is smaller than the widths of the electrode parts  23   a  and  23   b  in the first direction Dx. With such a configuration, the area of regions in which the first electrodes Tx and the second electrodes Rx overlap decreases and parasitic capacitance decreases. 
     The disposition interval between the first electrodes Tx in the second direction Dy is represented by Pt. The disposition interval Pt is about half of the disposition interval Pry between the bent parts  26   x  of each second electrode Rx. The present invention is not limited thereto, and the disposition interval Pt may be any other value than a half-integer multiple of the disposition interval Pry. The disposition interval Pt is, for example, 50 μm to 100 μm inclusive. In each first electrode Tx, adjacent coupling parts  24  in the first direction Dx are disposed on opposite sides at a disposition interval Pb in the second direction Dy. The electrode parts  23   a  and  23   b  each have a parallelogram shape but may have any other shape. For example, the electrode parts  23   a  and  23   b  may each have a rectangular shape, a polygonal shape, or a deformed shape. 
     The following describes the layer structure of the detection device  1  with reference to  FIG.  8   . In  FIG.  8   , a section in the frame region GA is a section of a part including a thin film transistor Tr included in the first electrode selection circuit  15 . In  FIG.  8   , a section taken along line VII-VII′ in the detection region FA and the section of the part including the thin film transistor Tr in the frame region GA are connected to illustrate the relation between the layer structure of the detection region FA and the layer structure of the frame region GA. 
     As illustrated in  FIG.  8   , the thin film transistor Tr is provided in the frame region GA of the detection device  1 . The thin film transistor Tr includes a semiconductor layer  61 , a source electrode  62 , a drain electrode  63 , and a gate electrode  64 . The gate electrode  64  is provided on the sensor substrate  21 . A first inter-layer insulating film  81  is provided on the sensor substrate  21  and covers the gate electrode  64 . The material of the gate electrode  64  is aluminum (Al), copper (Cu), silver (Ag), molybdenum (Mo), or alloy of these materials. The material of the first inter-layer insulating film  81  is a silicon oxide film (SiO), a silicon nitride film (SiN), or a silicon oxide nitride film (SiON). The first inter-layer insulating film  81  is not limited to a single layer but may be a film of a multilayered structure. For example, the first inter-layer insulating film  81  may be a film of a multilayered structure in which a silicon nitride film is formed on a silicon oxide film. 
     The semiconductor layer  61  is provided on the first inter-layer insulating film  81 . A second interlayer insulating film  82  is provided on the first inter-layer insulating film  81  and covers the semiconductor layer  61 . The semiconductor layer  61  is exposed at a bottom part of a contact hole provided through the second interlayer insulating film  82 . The material of the semiconductor layer  61  is polysilicon or oxide semiconductor. The material of the second interlayer insulating film  82  is a silicon oxide film, a silicon nitride film, or a silicon oxide nitride film. The second interlayer insulating film  82  is not limited to a single layer but may be a film of a multilayered structure. For example, the second interlayer insulating film  82  may be a film of a multilayered structure in which a silicon nitride film is formed on a silicon oxide film. 
     The source electrode  62  and the drain electrode  63  are provided on the second interlayer insulating film  82 . The source electrode  62  and the drain electrode  63  are each coupled to the semiconductor layer  61  through a contact hole provided through the second interlayer insulating film  82 . The material of the source electrode  62 , the drain electrode  63 , and the coupling parts  24  is titanium aluminide (TiAl), which is an alloy of titanium and aluminum. 
     An insulating resin layer  27  and the electrode parts  23   b  and the coupling parts  24  of the first electrodes Tx are provided on the second interlayer insulating film  82 . The resin layer  27  provided in the frame region GA covers the source electrode  62  and the drain electrode  63 . The drain electrode  63  is electrically coupled to the corresponding first electrode Tx through a contact hole provided through the resin layer  27  provided in the frame region GA. 
     The resin layer  27  provided in the detection region FA includes a first resin layer  27 A and a second resin layer  27 B thinner than the first resin layer  27 A. The first resin layer  27 A covers a site positioned directly below the second electrode Rx at each coupling part  24 . The second resin layer  27 B provided in the detection region FA covers sites positioned directly below the electrode parts  23   b  at each coupling part  24 . 
     Contact holes H 1  and H 2  are provided through the second resin layer  27 B. In the detection region FA, a peripheral part of each electrode part  23   b  is coupled to the corresponding coupling part  24  through the contact holes H 1  and H 2 . In this example, the electrode part  23   b  contacts the second interlayer insulating film  82 . 
     The second electrodes Rx are provided on the first resin layer  27 A. Each second electrode Rx includes, for example, a first metal layer  141 , a second metal layer  142 , and a third metal layer  143 . The second metal layer  142  is provided on the third metal layer  143 , and the first metal layer  141  is provided on the second metal layer  142 . For example, the material of the first metal layer  141  and the third metal layer  143  is molybdenum or molybdenum alloy. The material of the second metal layer  142  is aluminum or aluminum alloy. Molybdenum or molybdenum alloy, of which the first metal layer  141  is made, has a lower visible light reflective index than aluminum or aluminum alloy, of which the second metal layer  142  is made. Accordingly, visual recognition of the second electrodes Rx can be prevented. 
     An insulating film  83  is provided on the resin layer  27 , each electrode part  23   b , and each second electrode Rx. The upper and side surfaces of the second electrode Rx are covered by the insulating film  83 . The insulating film  83  is a film having a high refractive index and a low reflective index, such as a silicon nitride film. 
     In the above-described configuration, the first electrodes Tx and the second electrodes Rx are formed on the same sensor substrate  21 . The first electrodes Tx and the second electrodes Rx are provided in different layers with the resin layer  27  interposed therebetween as an insulating layer. 
     In the present disclosure, a detection duration of the detection device  1  includes a first duration in which touch detection durations (coordinate detection durations) are continuously provided and a second duration in which touch detection durations and fingerprint detection durations (surface information detection durations) are alternately repeated, each touch detection duration being a duration in which touch detection is executed, each fingerprint detection duration being a duration in which fingerprint detection is executed.  FIG.  9    is a timing chart illustrating exemplary operation of switching between the first duration and the second duration. In  FIG.  9   , TP represents each touch detection duration (coordinate detection duration), and FP represents each fingerprint detection duration (surface information detection duration). 
     As illustrated in  FIG.  9   , the detection device  1  according to the present embodiment switches the first duration and the second duration in accordance with a result of touch determination in a touch detection duration TP in the first duration and the second duration. More specifically, as illustrated in  FIG.  9   , the first duration transitions to the second duration when a touched state is detected in a touch detection duration TP in the first duration, and the second duration transitions to the first duration when a non-touched state is detected in a touch detection duration TP in the second duration. 
     Although  FIG.  9    illustrates the example in which touch detection and fingerprint detection are alternately executed in the second duration, the present invention is not limited thereto, and for example, fingerprint detection may be executed after touch detection is executed a plurality of times. 
     The following describes specific detection modes in touch detection and fingerprint detection.  FIG.  10    is a diagram illustrating an exemplary first detection mode for executing touch detection in a touch detection duration.  FIG.  11    is a diagram illustrating an exemplary second detection mode for executing fingerprint detection in a fingerprint detection duration.  FIG.  12    is a diagram illustrating an exemplary third detection mode for executing fingerprint detection in a fingerprint detection duration. 
     As illustrated in  FIG.  10   , in the first detection mode M 1 , the detection device  1  performs detection of the finger Fin or the like, more specifically, detection of the position of the finger on the detection surface (the coordinate position of the finger on the detection surface) by scanning the entire detection region FA at a first detection pitch Pts that is larger than in the second detection mode M 2  (refer to  FIG.  11   ). In the first detection mode M 1 , the first electrode selection circuit  15  supplies the first drive signal Vtx 1  to each first electrode block as a bundle of a plurality of first electrodes Tx that are adjacent to each other or disposed at a predetermined pitch. The same first drive signal Vtx 1  is supplied to the first electrodes Tx included in at least one first electrode block BK. Accordingly, in the first detection mode M 1 , detection can be performed at the first detection pitch Pts that is larger than in the second detection mode M 2  to be described later. In the first detection mode M 1 , the detection electrode selection circuit  16  may supply the second drive signal Vtx 2  to each second electrode block as a bundle of a plurality of second electrodes Rx that are adjacent to each other or disposed at a predetermined pitch. All second electrodes Rx may be coupled to the detector  40 . 
     As illustrated in  FIG.  11   , in the second detection mode M 2 , the detection device  1  performs detection of the finger Fin or the like, more specifically, detection of concavity-convexity of the surface of the detection target body on the detection surface (for example, a fingerprint image of the detection target body contacting the detection surface) by scanning the entire detection region FA at a second detection pitch Pf that is smaller than in the first detection mode M 1  (refer to  FIG.  10   ). In the second detection mode M 2 , the first electrode selection circuit  15  supplies the second drive signal Vtx 2  having a phase determined based on a predetermined sign to each first electrode Tx. Alternatively, the first electrode selection circuit  15  may individually scan each first electrode and supply a pulsed wave as the second drive signal Vtx 2  along with the scanning. Hereinafter, supply of the second drive signal Vtx 2  includes any of these aspects. Accordingly, in the second detection mode M 2 , the detection device  1  can perform detection at the second detection pitch Pf that is smaller than in the first detection mode M 1 . More specifically, even in a state in which the finger is contacting the detection surface from the standpoint of a macroscopic viewpoint, part of the finger is contacting the detection surface but the other part is slightly separated from the detection surface from the standpoint of a microscopic viewpoint due to concavity-convexity of the surface of the finger. In the second detection mode M 2 , concavity-convexity of the surface of the detection target body (in this example, concavity-convexity of the surface of the finger, in other words, the fingerprint) in the microscopic viewpoint is detected. The second detection pitch only needs to be smaller than the first detection pitch, and the smallest second detection pitch is the pitch between two adjacent first electrodes or two adjacent detection electrodes intersecting them. 
     In the second detection mode M 2 , the detection device  1  performs detection in the entire detection region FA. Thus, the detection device  1  is not limited to fingerprint detection but may detect, for example, a palm print. Alternatively, the detection device  1  may detect the shape of a hand contacting or nearby the detection region FA and specify the position of a fingertip. In this case, a fingerprint can be detected by performing signal processing and arithmetic processing only in a region that the fingertip contacting or nearby. 
     Touch detection in the first detection mode M 1  is executed in the first duration, and touch detection in the first detection mode M 1  and fingerprint detection in the second detection mode M 2  are repeatedly executed in the second duration. Accordingly, the first duration in which touch detection durations TP are continuously provided, and the second duration in which touch detection durations TP and fingerprint detection durations FP are alternately repeated are achieved. 
     In fingerprint detection, a region in which fingerprint detection is performed on the detection surface may be a partial region on the detection surface. For example, in the third detection mode M 3 , the detection device  1  performs detection at the second detection pitch Pf in a first partial region FA 1  as part of the detection region FA as illustrated in  FIG.  12   . In the third detection mode M 3 , the first electrode selection circuit  15  supplies the second drive signal Vtx 2  only to a plurality of first electrodes Tx included in the first partial region FA 1 . In the third detection mode M 3  as well, the detection device  1  can perform detection at the second detection pitch Pf. For example, in the third detection mode M 3 , since detection is performed only in the first partial region FA 1 , the time taken for detection is shortened and processing  9  performed by the detector  40  (refer to  FIG.  4   ) is reduced. The first partial region FA 1  is a fixed region that is set in advance. However, the position and size of the first partial region FA 1  may be modified as appropriate. 
     Fingerprint detection may be executed in the third detection mode M 3  in place of the second detection mode M 2  described above. Specifically, touch detection in the first detection mode M 1  is executed in the first duration, and touch detection in the first detection mode M 1  and fingerprint detection in the third detection mode M 3  are repeatedly executed in the second duration. Accordingly, although a region in which fingerprint detection is performed is limited to the first partial region FA 1  smaller than the detection region FA, the fingerprint detection duration FP is shortened and the time taken for detection is shortened. 
       FIG.  13    is a diagram illustrating an exemplary fourth detection mode for repeatedly executing touch detection and fingerprint detection. For example, the detection device  1  executes touch detection in the first detection mode M 1  in each touch detection duration TP in the first duration and detects whether the finger is contacting the detection surface. When having detected the finger Fin or the like, the detection device  1  transitions to the second duration and repeatedly executes touch detection in the first detection mode M 1  and fingerprint detection in the fourth detection mode M 4 . In detection in the fourth detection mode M 4 , the detection device  1  performs detection at the second detection pitch Pf only in a second partial region FA 2  as a predetermined region including a position at which the finger Fin or the like is detected. The position and size of the second partial region FA 2  may be modified based on information of the finger Fin or the like detected in a touch detection duration TP. In this manner, fingerprint detection in the fourth detection mode M 4  may be performed based on a result of detection in the first detection mode M 1 . Accordingly, the area of the second partial region FA 2  can be reduced and thus the time taken for detection is shortened. 
     As illustrated in  FIG.  4   , the processor  50  includes a touch determiner  51 , a second storage  52 , a coordinate determiner  53 , an authentication determiner  54 , and a third storage  55 . 
     The second storage  52  and the third storage  55  may be each, for example, a random access memory (RAM), a read only memory (ROM), or a register circuit. In the present embodiment, the second storage  52  stores, as buffering data, a fingerprint image that is output as the sensor output Vo from the detector  40 . The third storage  55  stores, as authentication data, the fingerprint image stored as buffering data in the second storage  52 . The third storage  55  also stores a result of determination by the authentication determiner  54 . 
     The touch determiner  51  determines whether the current state is a touched state based on the sensor output Vo output from the detector  40 . Specifically, for example, when having determined that the current state is a touched state in a touch detection duration TP in the first duration, the touch determiner  51  outputs a first control signal for transition to the second duration to the detection controller  11 . For example, when having determined that the current state is a non-touched state in a touch detection duration TP in the second duration, the touch determiner  51  outputs a second control signal for transition to the first duration to the detection controller  11  and the authentication determiner  54 . 
     The coordinate determiner  53  stores the sensor output Vo output from the detection data generator  49  of the detector  40  in the second storage  52  as buffering data. More specifically, after the detection duration has entered the second duration, a touch panel coordinate detected in a touch detection duration and fingerprint image data generated in a fingerprint detection duration right after the touch detection duration are combined by the detection data generator  49 , and this combined data is output to the processor  50  as the sensor output Vo. The touch panel coordinate and the fingerprint image data thus paired are stored as buffering data in the second storage  52 . 
     In addition, the coordinate determiner  53  calculates the difference value between the touch panel coordinate stored as buffering data in the second storage  52  and a touch panel coordinate acquired after the fingerprint detection duration FP in the second duration, and when the difference value is equal to or larger than a predetermined value, the coordinate determiner  53  discards the fingerprint image generated in the previous fingerprint detection duration FP and stored as buffering data in the second storage  52 . 
     The coordinate determiner  53  calculates the difference value between the touch panel coordinate stored as buffering data in the second storage  52  and the touch panel coordinate acquired after the fingerprint detection duration FP in the second duration, and when the difference value is smaller than the predetermined value, the coordinate determiner  53  stores, as authentication data in the third storage  55 , the fingerprint image generated in the previous fingerprint detection duration FP and stored as buffering data in the second storage  52 . 
     The authentication determiner  54  determines authentication of the authentication data stored in the third storage  55  based on the second control signal from the touch determiner  51  and stores a result of the authentication in the third storage  55 . The present disclosure is not limited by this authentication determination method. 
     The following describes specific examples of processing at the processor  50  of the detection device according to the first embodiment with reference to  FIGS.  14 A and  15   .  FIG.  14 A  is a flowchart illustrating exemplary authentication data acquisition processing at the processor of the detection device according to the first embodiment.  FIG.  15    is a flowchart illustrating exemplary authentication processing at the processor of the detection device according to the first embodiment. 
     As a precondition of the authentication data acquisition processing illustrated in  FIG.  14 A , it is assumed that the detection device  1  is continuously executing touch detection to detect existence of a touch on the detection surface in the first duration. It is also assumed that an authentication data accumulation number m and an authentication data acquisition time (count value) t are reset (m=0 and t=0). 
     The touch determiner  51  determines whether the current state is a touched state based on a touch panel coordinate acquired in a touch detection duration in the first duration (step S 101 ). When having determined that the current state is a non-touched state (No at step S 101 ), the touch determiner  51  repeatedly executes the processing at step S 101 . 
     When having determined that the current state is a touched state (Yes at step S 101 ), the touch determiner  51  outputs the first control signal to the detection controller  11  (step S 102 ). Accordingly, the detection device  1  transitions to the second duration. The sensor output Vo(n) in the second duration thereafter is a pair of a touch panel coordinate (x n , y n ) acquired in a touch detection duration TP(n) and fingerprint image data (Dn) acquired in the fingerprint detection duration FP(n) in the touch detection duration right after. 
     The coordinate determiner  53  receives the sensor output Vo(n) from the detection data generator  49  of the detector  40  and stores, as buffering data in the second storage  52 , the touch panel coordinate (x n , y n ) acquired in the touch detection duration TP(n) in the second duration and the fingerprint image data (D n ) acquired in the fingerprint detection duration FP(n) in the second duration (step S 103 ). 
     The touch determiner  51  determines whether the current state is a touched state based on the touch panel coordinate (x n , y n ) (step S 104 ). When having determined that the current state is a non-touched state (No at step S 104 ), the touch determiner  51  discards the touch panel coordinate (x n , y n ) and the fingerprint image data (D n ) stored in the second storage  52  (step S 105 ). In this case, the processor  50  resets the authentication data accumulation number m and the authentication data acquisition time (count value) t (m=0 and t=0) (step S 106 ). Then, the touch determiner  51  outputs the second control signal to the detection controller  11  (step S 107 ). Accordingly, the detection device  1  transitions to the first duration and repeatedly executes the processing at step S 101  and later. 
     When the touch determiner  51  determines that the current state is a touched state (Yes at step S 104 ), the coordinate determiner  53  additionally stores, as buffering data in the second storage  52 , a touch panel coordinate (x n+1 , y n+1 ) in a touch detection duration TP (n+1) and fingerprint image data (D n+1 ) in a fingerprint detection duration FP(n+1), which are included in the next sensor output Vo(n+1) (step S 108 ). 
     Subsequently, the coordinate determiner  53  determines whether a difference value (Δx, Δy) between two consecutive touch panel coordinates stored in the second storage  52 , in other words, the touch panel coordinate (x n , y n ) and the touch panel coordinate (x n+1 , y n+1 ) is equal to or smaller than a predetermined value (step S 109 ). 
     When the difference value (Δx, Δy) is larger than the predetermined value (No at step S 109 ), the coordinate determiner  53  discards the touch panel coordinate (x n , y n ) and the fingerprint image data (D n ) stored in the second storage  52  (step S 110 ) and transitions to processing at step S 113 . The predetermined value is preferably zero. 
     When the difference value (Δx, Δy) is equal to or smaller than the predetermined value (Yes at step S 109 ), the coordinate determiner  53  stores, as authentication data in the third storage  55 , the fingerprint image data (D n ) stored in the second storage  52  (step S 111 ). In this case, the processor  50  increments the authentication data accumulation number m (step S 112 ) and transitions to the processing at step S 113 . Accordingly, a plurality of pieces of fingerprint image data are sequentially accumulated as authentication data. 
     At step S 113 , the processor  50  determines whether the authentication data accumulation number m is smaller than a predetermined authentication data accumulation number upper limit M. When the authentication data accumulation number m has reached the predetermined authentication data accumulation number upper limit M (No at step S 113 ), the processor  50  resets the authentication data accumulation number m and the authentication data acquisition time (count value) t (m=0 and t=0) (step S 106 ). Then, the touch determiner  51  outputs the second control signal to the detection controller  11  (step S 107 ). Accordingly, the detection device  1  transitions to the first duration and repeatedly executes the processing at step S 101  and later. 
     When the authentication data accumulation number m is smaller than the predetermined authentication data accumulation number upper limit M (Yes at step S 113 ), the detection device  1  transitions to processing at step S 114 . 
     At step S 114 , the processor  50  determines whether the authentication data acquisition time (count value) t is smaller than a predetermined authentication data acquisition time upper limit T. When the authentication data acquisition time (count value) t has reached the predetermined authentication data acquisition time upper limit T (No at step S 114 ), the processor  50  resets the authentication data accumulation number m and the authentication data acquisition time (count value) t (m=0 and t=0) (step S 106 ). Then, the touch determiner  51  outputs the second control signal to the detection controller  11  (step S 107 ). Accordingly, the detection device  1  transitions to the first duration and repeatedly executes the processing at step S 101  and later. 
     When the authentication data acquisition time (count value) t is smaller than the predetermined authentication data acquisition time upper limit T (Yes at step S 114 ), the touch panel coordinate (x n+1 , y n+1 ) acquired in the touch detection duration TP(n+1) is set as the touch panel coordinate (x n , y n ) acquired in the touch detection duration TP(n) (step S 115 ), and the processing at step S 103  and later are repeatedly executed. 
     Through the authentication data acquisition processing described above, authentication data having a high certainty is accumulated in the third storage  55 . 
     When it is determined that the current state is not a touched state in the second duration (No at step S 104 ), when the authentication data accumulation number m has reached the predetermined authentication data accumulation number upper limit M (No at step S 113 ), or when the authentication data acquisition time (count value) t has reached the predetermined authentication data acquisition time upper limit T (No at step S 114 ), the processor  50  holds, as protect data, a plurality of pieces of authentication data stored in the third storage  55  and executes the authentication processing illustrated in  FIG.  15   . 
     The authentication determiner  54  determines whether authentication data before authentication determination (hereinafter also referred to as “pre-determination data”) accumulated as protect data in the third storage  55  exists (step S 201 ). When pre-determination data exists in the third storage  55  (Yes at step S 201 ), the authentication determiner  54  reads the existing pre-determination data from the third storage  55  (step S 202 ), executes predetermined authentication determination processing (step S 203 ), and stores a result of the authentication determination processing in the third storage  55  (step S 204 ). Collation data necessary for the authentication determination processing is transferred from a host to the authentication determiner  54  and stored in advance. 
     When no pre-determination data exists in the third storage  55  (No at step S 201 ), the authentication processing illustrated in  FIG.  15    ends. Since authentication data is stored as protect data in the third storage  55 , for example, temporally sequential management and prioritization management of the authentication data are possible. 
     After the authentication processing described above, the processor  50  outputs an authentication determination processing result stored in the third storage  55  in accordance with authentication result request from the control circuit  7  as a host device at a higher level. 
     In the authentication data acquisition processing illustrated in  FIG.  14 A , a fingerprint image when the difference value (Δx, Δy) between the touch panel coordinate (x n , y n ) as a touch detection coordinate in the touch detection duration TP(n) and the touch panel coordinate (x n+1 , y n+1 ) as a touch detection coordinate in the touch detection duration TP(n+1) is smaller than the predetermined value (Yes at step S 109 ) can be acquired and accumulated in the third storage  55  in the second duration. Accordingly, the accuracy of a fingerprint image used in the authentication processing illustrated in  FIG.  15    is increased. 
     In the authentication processing illustrated in  FIG.  15   , the authentication determination processing result is stored in the third storage  55  before the authentication result request. Accordingly, a time loss in response to the authentication result request is reduced. Alternatively, an authentication result may be accumulated irrespective of existence of the authentication result request from the host device, and as a result, a time loss along with fingerprint authentication is reduced. 
     The present embodiment is described above with the example in which the authentication data accumulation number m is provided with the upper limit M and the authentication data acquisition time (count value) t is provided with the upper limit T, but the present invention is not limited thereto. For example, the authentication data accumulation number m may be provided with no upper limit M, and the reset processing of the authentication data accumulation number m at steps S 112 , S 113 , and S 106  illustrated in  FIG.  14 A  may be omitted. Alternatively, the authentication data acquisition time (count value) t may be provided with no upper limit T, and the reset processing of the authentication data acquisition time (count value) t at steps S 114  and S 106  illustrated in  FIG.  14 A  may be omitted. 
     According to the present embodiment, the detection device  1  that can improve authentication accuracy is obtained. 
       FIG.  14 B  illustrates a modification of the authentication data acquisition processing illustrated in  FIG.  14 A . Any content common to  FIG.  14 A  is denoted by the same reference sign and description thereof is omitted. 
     As illustrated in  FIG.  14 B , when the authentication data accumulation number m has reached the predetermined data accumulation number upper limit M (No at step S 113 ) or when the authentication data acquisition time (count value) t has reached the predetermined authentication data acquisition time upper limit T (No at step S 114 ), the processor  50  resets the authentication data accumulation number m and the authentication data acquisition time (count value) t (m=0 and t=0) (step S 106   a ), and thereafter returns to step S 115 . 
     When having determined that the current state is not a touched state at step S 104 , in other words, when having determined that the finger moved away from the detection surface, the touch determiner  51  discards the touch panel coordinate (x n , y n ) and the fingerprint image data (D n ) stored in the second storage  52  (step S 105 ). Then, the processor  50  further determines whether the authentication data accumulation number m is smaller than a predetermined data accumulation number value MT (step S 121 ), and further determines whether the authentication data acquisition time (count value) t is smaller than a predetermined data acquisition time value TT (step S 122 ). 
     In the case of Yes determination at step S 121  or S 122 , the processor  50  determines that fingerprint image data (authentication data) for transition to fingerprint authentication is not sufficiently accumulated, discards a plurality of pieces of fingerprint image data stored as authentication accumulated data in the third storage  55  (step S 124 ), and resets the authentication data accumulation number m and the authentication data acquisition time (count value) t (m=0 and t=0) (step S 125 ). Then, the touch determiner  51  outputs the second control signal to the detection controller  11  (step S 126 ). Accordingly, the detection device  1  transitions to the first duration and repeatedly executes the processing at step S 101  and later. 
     In the case of No determination at steps S 121  and S 122 , the processor  50  determines that fingerprint image data (authentication data) for transition to fingerprint authentication is sufficiently accumulated, and holds and stores, as authentication protect data in the third storage  55 , a plurality of pieces of fingerprint image data stored as accumulated data in the third storage  55  (step S 123 ). 
     Thereafter, the authentication determiner  54  executes fingerprint authentication illustrated in  FIG.  15    by using protect data stored in the third storage  55 . The touch determiner  51  outputs the second control signal to the detection controller  11  (step S 127 ). Accordingly, the detection device  1  transitions to the first duration and repeatedly executes the processing at step S 101  and later. 
     In the authentication data acquisition processing of the above-described modification, any one of steps S 121  and S 122  may be omitted. Similarly, any one or both of steps S 113  and S 114  may be omitted. 
     Second Embodiment 
       FIG.  16    is a block diagram illustrating an exemplary configuration of the detection system according to a second embodiment. Duplicate description of any component equivalent or identical to that in the first embodiment described above is omitted. 
     A detection system  2   a  illustrated in  FIG.  16    includes a detection device  1   a  and a control circuit  7   a.    
     The present embodiment will be described for a configuration in which the processor  50  included in the detection device  1  of the first embodiment is included in the control circuit  7   a  as a host device at a higher level. In other words, in the detection system  2   a  illustrated in  FIG.  16   , the detection controller  11  and the processor  50  are included in the control circuit  7   a . The detector  40  is included in a detection circuit  6   a.    
     The following describes a specific example of the authentication data acquisition processing in the detection system  2   a  according to the second embodiment with reference to  FIG.  17   .  FIG.  17    is a sequence diagram illustrating the specific example of the authentication data acquisition processing in the detection system according to the second embodiment. The authentication data acquisition processing according to the second embodiment has the same flowchart as in the first embodiment, and thus any duplicate processing thereof will be described with reference to  FIG.  14 A . 
     As a precondition of the processing illustrated in  FIG.  17   , it is assumed that the detection circuit  6   a  outputs the sensor output Vo to the control circuit  7   a . It is also assumed that the authentication data accumulation number m and the authentication data acquisition time (count value) t are reset (m=0 and t=0) at the control circuit  7   a.    
     When the detection circuit  6   a  is continuously executing touch detection in the first duration (step S 1 ), the control circuit  7   a  determines whether the current state is a touched state based on a touch panel coordinate acquired in a touch detection duration in the first duration (step S 2 ) (step S 101  in  FIG.  14 A ). When having determined that the current state is a touched state (Yes at step S 101 ), the control circuit  7   a  outputs the first control signal to the detection device  1   a  (step S 102  in  FIG.  14 A ). Accordingly, the detection circuit  6   a  transitions to the second duration (step S 3 ). 
     The control circuit  7   a  receives the sensor output Vo(n) from the detection data generator  49  of the detector  40  and stores, as buffering data in the second storage  52 , the touch panel coordinate (x n , y n ) acquired in the touch detection duration TP(n) in the second duration and the fingerprint image data (D n ) acquired in the fingerprint detection duration FP(n) in the second duration (step S 4 ) (step S 103  in  FIG.  14 A ). 
     The control circuit  7   a  determines whether the current state is a touched state based on the touch panel coordinate (x n , y n ) (step S 9 ) (step S 104  in  FIG.  14 A ). When having determined that the current state is a touched state (Yes at step S 104 ), the control circuit  7   a  additionally stores, as buffering data in the second storage  52 , the touch panel coordinate (x n+1 , y n+1 ) in the touch detection duration TP(n+1) and the fingerprint image data (D n+1 ) in the fingerprint detection duration FP(n+1) (step S 4 ), which are included in the next sensor output Vo(n+1) (step S 108  in  FIG.  14 A ). 
     Subsequently, the control circuit  7   a  determines whether the difference value (Δx, Δy) between two consecutive touch panel coordinate stored in the second storage  52 , in other words, the touch panel coordinate (x n , y n ) and the touch panel coordinate (x n+1 , y n+1 ) is smaller than the predetermined value (step S 109  in  FIG.  14 A ). When the difference value (Δx, Δy) is smaller than the predetermined value (Yes at step S 109 ), the fingerprint image data (D n ) stored in the second storage  52  is stored as authentication data in the third storage  55  (step S 111  in  FIG.  14 A ). The control circuit  7   a  sets the touch panel coordinate (x n+1 , y n+1 ) acquired in the touch detection duration TP(n+1) as the touch panel coordinate (x n , y n ) acquired in the touch detection duration TP(n) (step S 115  in  FIG.  14 A ). 
     Subsequently, the control circuit  7   a  determines whether the current state is a touched state based on the touch panel coordinate (x n+1 , y n+1 ) acquired in the touch detection duration TP(n+1) in the second duration (step S 6 ) (step S 104  in  FIG.  14 A ). When having determined that the current state is a non-touched state (No at step S 104 ), the control circuit  7   a  discards the touch panel coordinate (x n , y n ) and the fingerprint image data (D n ) stored in the second storage  52  (step S 110 ) and outputs the second control signal to the detection circuit  6   a  (step S 107  in  FIG.  14 A ). Accordingly, the detection circuit  6   a  transitions to the first duration (step S 7 ). 
     In this manner, the control circuit  7   a  acquires a fingerprint image when the difference value (Δx, Δy) between the touch panel coordinate (x n , y n ) as a touch detection coordinate in the touch detection duration TP(n) and the touch panel coordinate (x n+1 , y n+1 ) as a touch detection coordinate in the touch detection duration TP(n+1) is smaller than the predetermined value (Yes at step S 109 ) in the second duration. Accordingly, authentication data having a high certainty is obtained. 
     The following describes a specific example of the authentication processing in the detection system  2   a  according to the second embodiment with reference to  FIG.  18   .  FIG.  18    is a sequence diagram illustrating the specific example of the authentication processing in the detection system according to the second embodiment. The authentication processing according to the second embodiment has the same flowchart as in the first embodiment, and thus any duplicate processing thereof will be described with reference to  FIG.  15   . 
     The control circuit  7   a  determines whether of pre-determination data exists (step S 201 ). When pre-determination data exists (Yes at step S 201 ), the control circuit  7   a  reads the existing pre-determination data (step S 202 ), executes predetermined authentication determination processing (step S 203 ), and stores a result of the authentication determination processing (step S 204 ). 
     Subsequently, the control circuit  7   a  determines whether pre-determination data exists (step S 201 ). When no pre-determination data exists (No at step S 201 ), the control circuit  7   a  ends the authentication processing (step S 21 ). 
     The control circuit  7   a  responds to an authentication result request (step S 22 ) and outputs the stored authentication determination processing result (step S 23 ). Accordingly, a time loss in response to the authentication result request is reduced. 
     According to the present embodiment, the detection system  2   a  that can improve authentication accuracy is obtained. 
     The second embodiment is described above with the example in which all components of the processor  50  are included in the control circuit  7   a , but the present invention is not limited thereto. For example, the control circuit may only include the authentication determiner  54 , whereas the touch determiner  51 , the second storage  52 , the coordinate determiner  53 , and the third storage  55  may be included in the detection circuit. 
     In the second embodiment as well, the above-described authentication data acquisition processing illustrated in  FIG.  14 B  may be executed. 
     Third Embodiment 
       FIG.  19    is a block diagram illustrating an exemplary configuration of a detection system according to a third embodiment. In this a detection system  2   b  according to the present embodiment, a detection device  1   b  includes the sensor unit  10 , the detection controller  11 , the first electrode selection circuit  15 , the detection electrode selection circuit  16 , the detector  40 , the processor  50 , and the detection controller  11 . The detection controller  11 , the detector  40 , and the processor  50  are included in a detection circuit  6   b.    
     In the detection system  2   b  according to the third embodiment illustrated in  FIG.  19   , an authentication determination processing result in stored in the third storage  55  of the processor  50  is output in accordance with authentication result request from a control device as a host device at a higher level. With this configuration according to the third embodiment, it is possible to obtain the same effects as in the configurations described above in the first and second embodiments. 
     The embodiments are described above with the configuration including the first storage in which a touch detection coordinate and a fingerprint image are stored as buffering data, the second storage in which a fingerprint image output as the sensor output Vo from the detector is stored as buffering data, and the third storage in which the fingerprint image stored as buffering data in the second storage is stored as authentication data or a result of determination by the authentication determiner is stored, but the configuration of the storages is not limited thereto. For example, the first storage, the second storage, and the third storage may be provided as one storage, and for example, the second storage and the third storage of the processor may be provided as one storage. 
     In the third embodiment as well, the above-described authentication data acquisition processing illustrated in  FIG.  14 B  may be executed. 
     Preferable embodiments of the present disclosure are described above, but the present disclosure is not limited to the embodiments. Contents disclosed in the embodiments are merely exemplary, and various kinds of modifications are possible without departing from the scope of the present disclosure. Modifications made as appropriate without departing from the scope of the present disclosure naturally belong to the technical scope of the present disclosure.