JP4632129B2 - Image reading device - Google Patents

Description

The present invention relates to an image reading apparatus for reading a subject image while rotating movement (rolling) a subject which has been brought into contact with the detection surface.

  In recent years, due to changes in the social situation, techniques relating to personal identification or personal identification for identifying individuals have been rapidly adopted in various fields such as immigration control, crime prevention, network access, and information management. Traditionally, as a method for identifying and authenticating an individual, in addition to the well-known fingerprint imprinting, in recent years, a technique for targeting information unique to the living body such as the iris of the eyeball, veins of hands and fingers, and the human phase has been studied. Some of them are already in practical use. Also, with regard to authentication accuracy when identifying individuals, a wide range of technologies have been studied, from those requiring extremely high authentication accuracy to simple ones, depending on the field or system to which the individual identification technology is applied. Yes.

  For example, in immigration procedures in other countries (eg, the United States of America), fingerprinting is mandatory as a method of personal identification. At this time, a method for collecting a wide range of fingerprints, including even the sides of the fingers. May be adopted. Here, since the finger has a curved surface, it is necessary to copy the fingerprint onto the paper surface by attaching the ink to a wide range including the side surface of the finger, placing the finger on the paper surface, and rotating the finger that is in close contact (rolling). There is. Furthermore, when performing fingerprint collation processing, it is necessary to take the fingerprint collected on the paper into a collation device and digitize it, and the series of operations from fingerprint collection to collation is extremely complicated. Had the problem of becoming.

FIG. 26 is a schematic configuration diagram showing an example of a fingerprint reading device in the prior art.
For example, as shown in FIG. 26, as a technique for reducing the fingerprint collection and collation work as described above, a finger FG placed on a detection surface 811 set on one surface of a triangular prism (optical prism) 810 is used. A fingerprint image projected by irradiating light from the light source 820 is imaged using a two-dimensional sensor such as a CCD (individual imaging device) 830, converted into an electrical signal, and quantized and converted from a digital signal. Is obtained.

  Then, such a series of fingerprint reading operations are continuously performed for each rotation state of the finger FG (each rotation state in the rotational movement RLG), and the acquired image is acquired by the combining processing unit (or rotation combining unit) 840. By combining the data, it is possible to generate a wide range of fingerprint images (rotating fingerprint images) including the side surface of the finger FG.

  According to this, since the fingerprint image can be read sequentially by only the operation of rotating the finger FG on the flat detection surface 811 and the rotated fingerprint image can be quickly and easily acquired as a digital signal, the fingerprint is collected and verified. A series of operations up to can be easily performed. The fingerprint reading apparatus having such a configuration is described in detail in, for example, Patent Document 1 and Patent Document 2.

JP 2000-268162 A (Page 3, FIGS. 1 and 2) JP 2000-0667208 (pages 3 to 4, FIGS. 1 to 3)

  However, in the conventional technology as described above, an operation of reading a fingerprint image by the CCD 830 for each rotation state of the finger (subject) FG that rotates and moves on the detection surface 811 in order to generate one rotated fingerprint image. Is repeated several times, and processing for extracting and synthesizing the fingerprint image for each placement position in each rotation state is necessary. In addition to the extremely large size, there has been a problem in that the circuit scale and the product cost associated with the fingerprint reading operation and the image composition processing are increased.

  In the fingerprint reading operation described above, it is necessary to move the position (reading area) for reading the fingerprint image in accordance with the rotational movement of the finger. In this case, the finger placement position cannot be accurately grasped ( Therefore, there is a problem that the setting of the reading area and the timing control of the reading operation are complicated, an imaging error is likely to occur, and a rotated fingerprint image having a good image quality cannot be acquired.

In view of the above-described problems, the present invention, when imaging a subject having a curved surface (for example, a finger), appropriately rotates the subject in accordance with a predetermined reading operation timing, thereby obtaining good image quality. It is an object of the present invention to provide an image reading apparatus that can acquire a subject image (rotated fingerprint image) and that can reduce a processing burden related to the image reading operation and the like.

According to the first aspect of the present invention, an image display unit including a display pixel array in which a plurality of display pixels are two-dimensionally arranged, and arranged on the visual field side of the display pixel array, and the plurality of read pixels are two-dimensionally arranged. An image reading unit that includes a transmissive reading pixel array and that reads a fingerprint pattern of a finger that rotates and moves on a detection surface provided on the reading pixel array; and when reading the fingerprint pattern, the image display unit the display pixel array, the induction image as stimulating light to induce rotational movement of the finger, so that the display position of the induction image changes so as to correspond to the reading position of the fingerprint pattern, and a display control unit for displaying The read pixel receives the reflected light of the guide light emitted from the image display unit and irradiated on the finger rotating and moving on the detection surface via the read pixel array, and the fingerprint of the finger Characterized in that the turn is a photo sensor for reading the brightness information.

According to a second aspect of the present invention, in the image reading device according to the first aspect, the display pixel array is a transmissive liquid crystal display panel in which liquid crystal pixels are two-dimensionally arranged .

According to a third aspect of the invention, in the image reading apparatus according to claim 1, wherein the display pixel array, a display panel of the self-emission type and the display pixels are arranged two-dimensionally including a light emitting element, emitted from the display panel The light to be transmitted is transmitted to the visual field side through the reading pixel array .

According to the present invention, when a subject having a curved surface (for example, a finger) is imaged, the subject is appropriately rotated in accordance with a predetermined reading operation timing to obtain a subject image having a good image quality (rotated fingerprint image). ) Can be acquired, and the processing load related to the image reading operation and the like can be reduced.

Hereinafter, an image reading apparatus and an image reading method thereof according to the present invention will be described in detail with reference to embodiments.
[First Embodiment]
<Overall configuration>
First, the overall configuration of the image reading apparatus according to the present invention will be briefly described.

  FIG. 1 is an overall configuration diagram showing a first embodiment of an image reading apparatus according to the present invention. Here, FIG. 1A is a schematic perspective view of the image reading apparatus according to the present embodiment, and FIG. 1B is a schematic cross-sectional view of the image reading apparatus. In the present embodiment, a configuration is shown in which a transmissive display pixel array is provided as an image display unit, and a surface light source type backlight is disposed on the back side of the image display unit.

  As shown in FIGS. 1A and 1B, the image reading apparatus DVC according to the present embodiment is roughly divided into a transmissive image display unit 200 such as a liquid crystal display device, and a visual field side of the image display unit 200. A transmissive image reading unit 100 disposed on the upper side of the drawing, and a backlight (surface light source) 300 disposed on the back side of the image display unit 200 (opposite side of the visual field; lower side of the drawing). A configuration in which at least the image reading area of the subject defined by the reading pixel array 140 of the image reading unit 100 is set to overlap the image display area defined by the display pixel array 250 of the image display unit 200 in a plane. have.

  Here, in FIGS. 1A and 1B, for the sake of illustration, the image display unit 200 and the image reading unit 100 and the image display unit 200 and the backlight 300 are separated from each other. However, these configurations may have a laminated structure in close contact with each other, or a laminated structure in which an optical member such as a diffusion film or a polarizing plate is interposed between the components. You may have.

  Moreover, the backlight 300 applied to this embodiment consists of an acrylic board etc. which are arrange | positioned facing the back side of the image display part 200, for example, as shown to Fig.1 (a), (b). A configuration including the light guide plate 310 and the light source 320 formed on one side end face side of the light guide plate 310 and made of a cold cathode ray tube, a light emitting diode (LED), or the like can be applied. However, the present invention is not limited to this, and for example, a planar light source in which self-luminous elements such as organic electroluminescence elements (organic EL elements) and light emitting diodes are two-dimensionally arranged may be applied.

For example, as shown in FIGS. 1A and 1B, the image display unit 200 is a glass substrate disposed on one surface side (viewing side) of the light guide plate 310 that emits light in the backlight 300 described above. Transparent insulating substrate 210, transparent counter substrate 220 arranged to face one surface side (viewing side) of insulating substrate 210, and electrodes provided between insulating substrate 210 and counter substrate 220 A plurality of liquid crystal pixels (display pixels) arranged in a two-dimensional manner over the entire area of the image display area, and each liquid crystal pixel. The pixel transistor (which will be described in detail later) is included.
Here, the plurality of liquid crystal pixels that are two-dimensionally arranged in the image display area constitute a display pixel array 250. In addition, on the insulating substrate 210 in a region where the counter substrate 220 is not disposed, a display driving driver (gate driver and source driver described later) 230 for controlling the display operation of image information in the display pixel array 250. Etc. are provided.

  For example, as shown in FIGS. 1A and 1B, the image reading unit 100 includes a transparent insulating substrate 110 such as a glass substrate disposed on the visual field side of the image display unit 200 described above, and the insulating property. A reading pixel array 140 comprising a plurality of photosensors (reading pixels) two-dimensionally arranged on the image reading area on the substrate 110, and a scanning driver for controlling an image information reading operation in the reading pixel array 140 (Scanning control means) 120 and a reading driver (reading control means) 130 are provided.

  In the present embodiment, the light emitted from the backlight 300 passes through the insulating substrate 210 and the counter substrate 220 constituting the display pixel array 250 of the image display unit 200, and the read pixel array of the image reading unit 100. The desired image information displayed in the image display area can be made visible to the user (image display function) by being emitted to the visual field side through the insulating substrate 110 constituting 140, and the image reading unit The image pattern of the subject can be read by detecting the light irradiated and reflected on the subject placed in the 100 image reading area by each photo sensor constituting the reading pixel array 140 (image reading function).

Each configuration will be specifically described below.
<Image display section>
FIG. 2 is a main part configuration diagram showing an example of an image display unit applied to the image reading apparatus according to the present embodiment. Here, a case where a liquid crystal display device having a pixel structure and a driver structure corresponding to a known active matrix driving method is applied as the image display unit will be described.

  As shown in FIG. 2, an image display unit (liquid crystal display device) 200 according to this embodiment is roughly divided into a transmissive liquid crystal pixel array (display pixel array) in which a large number of liquid crystal pixels (display pixels) Px are two-dimensionally arranged. , A liquid crystal display panel) 250P, a scanning line SL that extends by connecting the liquid crystal pixels Px in each row of the liquid crystal pixel array 250P in the row direction, and a data line DL that extends by connecting each liquid crystal pixel Px in the column direction And a gate driver (scan driver) 231 connected to each scan line SL and a source driver (data driver) 232 connected to each data line DL. Here, the gate driver 231 and the source driver 232 constitute the display driving driver 230 shown in FIG.

  In FIG. 2, the vertical control signal is a control signal for sequentially generating and outputting a scanning signal for setting the liquid crystal pixel Px group of each row to the selected state in the gate driver 231, and the horizontal control signal is In the source driver 232, a control signal for generating and applying a display signal voltage for performing gradation display based on display data to each liquid crystal pixel Px set in a selected state by the gate driver 231. All of these control signals are generated and supplied by, for example, an LCD controller (timing control means) (not shown).

As shown schematically in FIG. 2, the liquid crystal pixel array 250P includes a matrix in which liquid crystal pixels Px are connected in the vicinity of intersections of a plurality of scanning lines SL and a plurality of data lines DL arranged orthogonal to each other. It has the structure arranged in the shape. Here, as is well known, each liquid crystal pixel Px includes a pixel transistor TFT having a gate terminal connected to the scanning line SL and a source terminal connected to the data line DL, and one end side ( A pixel electrode), and a common signal voltage Vcom is applied to the other end side (common electrode). And a storage capacitor Cs to which a common voltage Vcs (for example, the common signal voltage Vcom) is applied to the other end side (counter electrode) via the common line CL.
Note that the liquid crystal pixels Px shown in FIG. 2 may have a configuration in which a black matrix (not shown) made of a light shielding material is provided.

  For example, as shown in FIG. 2, the gate driver 231 scans each row based on vertical control signals (a start signal, a reference clock signal, an output enable signal, etc.) supplied from an LCD controller or the like that is schematically omitted. A shift register circuit unit 231s that sequentially outputs a shift signal corresponding to the line SL, and a shift signal that is sequentially output from the shift register circuit unit 231s are amplified to a predetermined signal level as a scanning signal to each scanning line SL. And an output buffer unit 231b for outputting.

  Further, for example, as shown in FIG. 2, the source driver 232 is configured based on horizontal control signals (a start signal, a reference clock signal, an output enable signal, etc.) output from an LCD controller or the like that is schematically omitted. A shift register circuit portion 232s that sequentially outputs shift signals corresponding to the data lines DL, and one row of display data (analog RGB) composed of analog signals at a timing based on the shift signals sequentially output from the shift register circuit portion 232s. A sample hold circuit unit 232h that captures and holds in units, and a signal voltage corresponding to display data held by the sample hold circuit unit 232h is amplified to a predetermined signal level as a display signal voltage to each data line DL. An output buffer unit 232b for output. .

  Note that the LCD controller (display control unit) (not shown) is based on at least the horizontal control signal and the vertical signal based on various timing signals such as a horizontal synchronization signal, a vertical synchronization signal, and a system clock supplied to the image display unit 200. A control signal is generated and supplied to the gate driver 231 and the source driver 232.

  In the drive control method in the image display unit 200 having such a configuration, first, display data for one row of the liquid crystal pixel array 250P is sequentially captured and held by the source driver 232 based on a horizontal control signal. On the other hand, based on the vertical control signal, the gate driver 231 sequentially applies scanning signals to the scanning lines SL arranged in the liquid crystal pixel array 250P to set the liquid crystal pixels Px in each row to a selected state. Then, in synchronization with the selection timing of the liquid crystal pixels Px in the row corresponding to the held display data, the source driver 232 applies the display signal voltage corresponding to the held display data to each display via each data line DL. By simultaneously applying to the pixels Px, the liquid crystal molecules filled in the liquid crystal pixels Px set in the selected state are controlled to an alignment state corresponding to the display data.

  By repeating such a series of operations for each row of the liquid crystal pixel array 250P, gradation display based on the display data is performed. At this time, the backlight 300 is turned on to emit radiated light. By transmitting the liquid crystal pixel array 250P from the back side to the visual field side, the displayed desired image information is visually recognized by the user.

<Image reading unit>
FIG. 3 is a main part configuration diagram illustrating an example of an image reading unit applied to the image reading apparatus according to the present embodiment. In the present embodiment and each of the embodiments described below, a case where a double gate type photosensor described later is applied as a reading pixel constituting the image reading unit will be described, but the present invention is not limited thereto. In essence, it is composed of a transmissive read pixel array, and the image information displayed on the image display unit described above can be viewed with good luminance gradation from the visual field side through the read pixel array. It goes without saying that other element structures and circuit configurations may be used.

  As shown in FIG. 3, the image reading unit 100 according to the present embodiment is roughly divided into a large number of photosensors (reading pixels; a double-gate photosensor described later) PS, for example, n rows × m columns (n, m is an arbitrary positive integer) transmissive photosensor array (reading pixel array) 140P arranged in a matrix, and a top gate line Lt extending by connecting the top gate terminals TG of each photosensor PS in the row direction. A bottom gate line Lb extending by connecting the bottom gate terminal BG of each photosensor PS in the row direction, and a drain line (data line) Ld extending by connecting the drain terminal D of each photosensor PS in the column direction. A source line (common line) Ls commonly connecting the source terminal S to a predetermined low potential voltage (for example, ground potential) Vss, and each top gate line A top gate driver 120T connected to the gate line Lt, a bottom gate driver 120B connected to each bottom gate line Lb, and a drain driver 130D connected to each drain line Ld. Here, the top gate driver 120T and the bottom gate driver 120B correspond to the scan driver 120 shown in FIG. 1, and the drain driver 130D corresponds to the readout driver 130.

  The top gate control signal shown in FIG. 3 is selectively output as signals φT1, φT2,... ΦTi,..., ΦTi,. This is a control signal for generating φTn (i is an arbitrary positive integer satisfying 1 ≦ i ≦ n), and the bottom gate control signal is used as one of a read voltage and a non-read voltage described later in the bottom gate driver 120B. , ΦBn,..., ΦBn, which are selectively output, are applied to each photosensor PS by a drain driver 130D. At the same time, the data voltage Vrd corresponding to the carrier stored in each photosensor PS is read. It is a control signal for controlling the teeth. All of these control signals are generated and supplied by, for example, a system controller (timing control means) (not shown).

(Photo sensor PS)
FIG. 4 is a schematic cross-sectional view showing the element structure of a photosensor applicable to the image reading unit according to this embodiment. Here, FIG. 4A is a schematic cross-sectional view illustrating a configuration example of the photosensor according to the present embodiment, and FIG. 4B is an equivalent circuit diagram of the photosensor according to the present embodiment.

As shown in FIG. 4A, the photosensor PS applicable to the image reading unit 100 (photosensor array 140P) described above is roughly an electron-hole pair by the incidence of excitation light (here, visible light). Are formed on both ends of the semiconductor layer 11 through impurity layers (ohmic contact layers) 17 and 18 made of n ⁺ silicon, respectively. A drain electrode 12 (drain terminal D) and a source electrode 13 (source terminal S) which are made of a conductive material selected from an alloy, aluminum, an aluminum alloy, and the like and are opaque to visible light, and above the semiconductor layer 11 (drawing) It is formed via a block insulating film (stopper film) 14 and an upper gate insulating film 15 on the upper side, and is formed of a tin oxide film or an ITO film (indium-silicon film). A top gate electrode TGx (first gate electrode; top gate terminal TG) that is transparent to visible light, and a lower portion below the semiconductor layer 11 (downward in the drawing). A bottom gate electrode BGx (second light-shielding) which is formed through the gate insulating film 16 and is made of a conductive material selected from chromium, chromium alloy, aluminum, aluminum alloy or the like and is opaque to light (has a light shielding property). Gate electrode; bottom gate terminal BG).

  That is, the photosensor PS applied to the photosensor array 140P according to this embodiment is a photosensor having a so-called double gate type thin film transistor structure (double gate type photosensor), and applies a semiconductor manufacturing technique. As shown in FIG. 4A, a thin film is formed on a transparent insulating substrate 110 such as a glass substrate. In addition, a protective insulating film (passivation film) 19 is formed on the entire surface of the insulating substrate 110 including the photosensor PS (view side; upper part of the drawing), and the upper surface of the protective insulating film 19 is detected on the detection surface DTC. As described above, by placing a subject, electrical, physical, and chemical damage to the photosensor PS is suppressed.

  In the photosensor PS shown in FIG. 4A, the top gate insulating film 15, the block insulating film 14, the insulating film constituting the bottom gate insulating film 16, and the protective insulating film provided on the top gate electrode TGx. 19 is made of a material having a high transmittance for visible light that excites the semiconductor layer 11, for example, silicon nitride, silicon oxide, or the like, so that it is provided on the insulating substrate 110 side (downward in the drawing). The light emitted from the light source (not shown; corresponding to the backlight 300 provided on the back side of the image display unit 200 described above) is transmitted upward in the drawing and provided on the upper surface of the protective insulating film 19. It has a structure that detects only light reflected by a subject placed on the detection surface DTC and incident on the photosensor PS (specifically, the semiconductor layer 11).

  A photosensor PS having an element structure as shown in FIG. 4A is generally represented by an equivalent circuit as shown in FIG. Here, TG is a top gate terminal electrically connected to the top gate electrode TGx, BG is a bottom gate terminal electrically connected to the bottom gate electrode BGx, and D is a drain electrically connected to the drain electrode 12. A terminal S is a source terminal electrically connected to the source electrode 13.

(Top gate driver 120T / Bottom gate driver 120B)
FIG. 5 is a schematic block diagram illustrating a configuration example of a top gate driver or a bottom gate driver applicable to the image reading unit according to the present embodiment. Here, since the top gate driver 120T and the bottom gate driver 120B have substantially the same configuration, in the following description, the configuration will be described mainly using the top gate driver as an example.

  For example, as shown in FIG. 5, the top gate driver 120T (or bottom gate driver 120B) is supplied as a top gate control signal (or bottom gate control signal) from a system controller or the like that is schematically omitted. Based on the signal, the reference clock signal, the output enable signal, etc., the start signal is sequentially shifted to the next stage at the timing based on the reference clock signal, and at the timing based on the output enable signal etc., the top gate line Lt (or .., SGn output as shift signals SG1, SG2,... SGn corresponding to the bottom gate line Lb), and shift signals SG1, SG2,. Amplify to a predetermined signal level and reset FaiTi (or read pulse FaiBi) as, each top gate line Lt (or bottom gate line Lb) is configured to have an output buffer 122 for output to the.

(Drain driver 130D)
FIG. 6 is a schematic block diagram illustrating a configuration example of the drain driver applicable to the image reading unit according to the present embodiment.
For example, as illustrated in FIG. 6, the drain driver 130 </ b> D is based on a start signal based on a start signal, a reference clock signal, an output enable signal, and the like that are supplied as a drain control signal from a system controller or the like that is schematically omitted. A shift register circuit portion 131 that sequentially shifts to the next stage at a timing based on the clock signal, and outputs the signals as shift signals SD1, SD2,... SDm corresponding to each drain line Ld at a timing based on the output enable signal and the like; A precharge circuit unit 135 for simultaneously applying a predetermined precharge pulse (precharge voltage Vpg) to each drain line Ld at a timing (precharge period described later) based on a precharge signal φpg supplied as a control signal; Supplied as drain control signal At a timing based on the sampling signal (reading period to be described later), each data voltage Vrd (drain line voltage VD) corresponding to the carrier accumulated in each photosensor PS is read out and held in parallel via each drain line Ld. The sampling circuit unit 134, the source follower circuit unit 133 that amplifies each data voltage Vrd read (held) by the sampling circuit unit 134 to a predetermined signal level, and the shift register circuit unit 131 sequentially output the data voltage Vrd. The amplified data voltage output from the source follower circuit unit 133 is extracted in time series at a timing based on the shift signals SD1, SD2,... SDm, converted into a serial signal, and output as a read data signal Vdata And a parallel-serial conversion circuit unit 132. It is.

(Driving control method of image reading unit)
Next, the above-described drive control method for the image reading unit will be described with reference to the drawings.
FIG. 7 is a timing chart illustrating an example of a drive control method in the image reading unit according to the present embodiment. FIG. 8 is a conceptual diagram showing an image reading operation when a fingerprint is read in the image reading unit according to the present embodiment. Here, in FIG. 8, for the convenience of illustration, a part of hatching that represents a cross-sectional portion of the photosensor array 140P is omitted.

For example, as shown in FIG. 7, the drive control method of the photosensor array 140P described above includes a reset period Trst, a charge accumulation period Ta, a precharge period Tprch, and a readout period Tread in a predetermined processing operation period (one processing cycle). This is realized by setting.
As shown in FIG. 7, first, in the reset period Trst, the reset signal φTi (for example, the top gate voltage) is applied to the top gate terminal TG of the i-th photosensor PS via the top gate line Lt by the top gate driver 120T. (= Reset pulse voltage) Vtg = + 15V high level) is applied to execute a reset operation (initialization operation) for releasing carriers (here, holes) accumulated in the semiconductor layer 11.

  Next, in the charge accumulation period Ta, by applying a low level bias voltage φTi (for example, top gate voltage Vtg = −15 V) to the top gate terminal TG by the top gate driver 120T, the reset operation is terminated, The accumulation operation (carrier accumulation operation) is started.

  Here, in the charge accumulation period Ta, as shown in FIG. 8, it is disposed below the transparent insulating substrate 110 on which the photosensor PS shown in FIG. 4 is formed (on the back side of the image display unit 200). The light (Lx) emitted from the backlight 300 passes through the image reading unit 100 (the image display unit 200) and the subject (finger FG) placed in close contact with the detection surface DTC on the upper surface of the photosensor array 140P. The reflected light Ly of the light Lx is incident on the semiconductor layer 11 through the top gate electrode TGx made of a transparent electrode layer. Thereby, electron-hole pairs are generated in the incident effective region (carrier generation region) of the semiconductor layer 11 according to the amount of light incident on the semiconductor layer 11 during the charge accumulation period Ta, and the semiconductor layer 11 and the block insulating film 14 Holes are accumulated in the vicinity of the interface (around the channel region).

  In the precharge period Tprch, the drain driver 130D precharges the drain terminal D via the drain line Ld based on the precharge signal φpg supplied as a drain control signal in parallel with the charge accumulation period Ta. A pulse (for example, precharge voltage Vpg = + 5 V) is applied, and a precharge operation for holding the charge in the drain electrode 12 is executed.

  Next, in the read period Tread, after the precharge period Tprch has elapsed, the read signal φBi (for example, the bottom gate voltage (= read pulse voltage) is applied to the bottom gate terminal BG via the bottom gate line Lb by the bottom gate driver 120B. ) Vbg = + 10V) is applied to the drain line Ld, the drain voltage VD (data voltage Vrd; voltage signal) corresponding to the carriers (holes) accumulated in the channel region during the charge accumulation period Ta is applied to the drain line Ld. A read operation is performed by the drain driver 130D via the.

  Here, the change tendency of the drain voltage VD (data voltage Vrd) during the application period (readout period) of the read pulse φBi is such that the voltage is steep when there are many carriers accumulated in the charge accumulation period Ta (bright state). On the other hand, when the number of accumulated carriers is small (dark state), it tends to decrease gradually. For example, the data voltage Vrd after a predetermined time has elapsed after the start of the read period Tread is detected. Accordingly, it is possible to detect the amount of light incident on the photosensor PS, that is, lightness data (lightness / darkness information) corresponding to the light / dark pattern of the subject.

  Then, with a series of brightness data detection operations for such a specific row (i-th row) as one processing cycle, for each row (i = 1, 2,... N) of the photosensor array 140P described above, Monochrome type image reading that reads a two-dimensional image pattern (fingerprint image) of a subject as lightness data from a photosensor array 140P composed of a photosensor PS having a double gate type thin film transistor structure by repeatedly executing equivalent operation processing. It can be operated as a part. Note that the drive control operation of the series of image reading units described above is controlled by, for example, a controller (see the third embodiment) described later.

<Image Reading Method of Image Reading Apparatus>
Next, the entire operation (fingerprint reading operation) in the case of reading a fingerprint in the image reading apparatus including the image display unit described above will be described in detail.
FIG. 9 is a flowchart showing an example of the overall operation when reading a fingerprint in the image reading apparatus according to the present embodiment. FIG. 10 is a schematic diagram illustrating an example of a demonstration display executed prior to the fingerprint reading operation in the image reading apparatus according to the present embodiment. FIG. 11 is a conceptual diagram showing the rotational movement of the finger in the operation of reading the fingerprint in the image reading apparatus according to the present embodiment.

  In the fingerprint reading operation in the image reading apparatus DVC according to the present embodiment, as shown in FIG. 9, first, prior to the reading operation of the image pattern of the subject (fingerprint reading operation), the actual subject (finger) in the fingerprint reading operation. The movement of the subject equivalent to the case of rotating the image is displayed as a demonstration image (guidance information) (step S101).

  Here, specifically, the demonstration image is displayed by first starting the fingerprint reading operation in the image display area ARi set in the image display unit 200 of the image reading device DVC, as shown in FIG. The side surface on one side (right side) of the finger is in close contact with the detection surface DTC on the photosensor array 140P on the side end region (starting region of rotational movement; in the figure, the right end region of the image display area ARi). The subject image FGi that is recognized as if it is present is displayed.

  Next, as shown in FIG. 10B, in the image display area ARi, for example, the finger is rotated from the state shown in FIG. A subject image FGi recognized so that the substantially front area (abdomen) is in close contact with the detection surface DTC is displayed. Further, as shown in FIG. 10C, the end point of the fingerprint reading operation is displayed in the image display area ARi. The finger is further rotated from the state shown in FIG. 10B to the end region (the end region of the rotational movement; in the figure, the left end region of the image display area ARi), and the other side of the finger ( The subject image FGi that is recognized as if the left side surface is in close contact with the detection surface DTC is displayed.

  In this way, the state of the rotational movement of the finger as the subject is displayed in time series in the order of FIGS. 10A to 10C, so that the finger placement position and the rotational movement of the finger in the fingerprint reading operation to be described later will be described. The method, the approximate speed of the rotational movement, and the like can be intuitively recognized by the user of the image reading apparatus DVC through vision.

  Here, in FIG. 10, only three states (start point, intermediate point, end point) of the finger rotation movement are shown as demonstration images showing the rotation movement of the finger. However, continuous images including these three states are predetermined. The frame-by-frame display may be displayed at the time interval, or the time interval may be further shortened and displayed as a smooth moving image. In short, any display may be used as long as it allows the user of the image reading apparatus DVC to intuitively recognize the finger placement position, the moving method, and the like in the fingerprint reading operation described later. In addition to the demonstration images as shown in (a) to (c), information related to the fingerprint reading operation may additionally use character information, illustrations, voice information, and the like.

  Next, as shown in FIG. 11A, the user makes the finger to be a subject tilt to the start point area of the image reading area ARs set in the image reading unit 100, and one side (right side) of the finger FG. The image reading unit described above is placed so that the side faces of the image are in close contact with each other (step S102), and then, for example, the user performs an operation such as pressing a switch for starting a fingerprint reading operation (step S103). Based on the drive control method in 100, as shown in FIGS. 11A to 11C, the image reading area ARs from one side (the right side of the drawing) to the other side (the drawing) corresponding to the rotational movement direction of the finger FG. A fingerprint reading operation (image reading operation) for reading a fingerprint is performed while scanning the reading region (row in which the reading operation is performed) RGs to the left side (step S104).

  Here, the fingerprint reading operation in step S104 is the same as the fingerprint reading operation for each row in order from the photosensor PS in the first row in the image reading unit 100 (photosensor array 140P) shown in FIG. In this case, the user performs the finger placement position and rotation based on the demonstration image displayed (immediately before) before the fingerprint reading operation. Since the movement method, the approximate speed of the rotation, and the like are recognized, the image reading unit 100 performs a reading operation by rotating the finger FG at the same timing as the demonstration image ( The finger FG is placed immediately above the photosensor PS in the reading region RGs), and a substantially desired region of the finger FG is in close contact with the detection surface DTC. It is possible to realize a state.

  Therefore, according to the image reading apparatus and the drive control method thereof according to the present embodiment, since the transmissive image reading unit is stacked on the image display unit, the image display is performed prior to the fingerprint reading operation. By displaying a demonstration image on the screen, it is possible to place a finger in a region that roughly corresponds to the position of the photosensor in the row where the image reading operation is performed, and to scan each row in the photosensor array. The finger can be rotated and moved approximately corresponding to the speed.

  Thereby, it is not necessary to control the timing of the image reading operation corresponding to the rotational movement of the finger, and it is not necessary to separately provide a guide display mechanism or the like for instructing the placement position of the finger during the image reading operation. Therefore, it is possible to acquire a fingerprint image (rotated fingerprint image) having good image quality while suppressing imaging errors with a simple control method and a simple device configuration.

  In particular, in the present embodiment, for each rotation state (placement position) of a finger (subject) that rotates and moves on the detection surface, a fingerprint image of a region in which the finger is in close contact can be read. The image reading operation in the region is repeatedly performed sequentially while scanning the reading region, so that only a single scanning drive control (reading operation) in the photosensor array can be performed, and a wide range of fingerprints including the side surface of the finger having a curved surface. Images can be acquired quickly and satisfactorily.

  In addition, since the read data signal output by the image reading operation for each row (reading area) of the photosensor array constitutes a part of the fingerprint image as it is, extraction and synthesis of the fingerprint image as shown in the above-described prior art. It is not necessary to perform complicated processing such as this, and the burden of operation processing can be reduced, and an image reading operation (fingerprint reading operation) can be appropriately executed with a simple circuit configuration.

  Furthermore, in the present embodiment, as a configuration of the image reading device, a transmission type photo manufactured using a thin film technology on a transparent insulating substrate on the visual field side of a thin image display unit made of a liquid crystal display device or the like. Since it has a configuration in which an image reading unit with a sensor array is arranged (laminated), it reads images compared to a device configuration with an optical system using a triangular prism, CCD, etc. as shown in the prior art. The entire apparatus (fingerprint reading apparatus) can be greatly reduced in size and thickness, and the image reading apparatus can be favorably applied to a small electronic device or the like.

<Another configuration example of the image reading apparatus>
Next, another configuration example of the image reading apparatus according to the present embodiment will be described.
FIG. 12 is an overall configuration diagram illustrating another example of the image reading apparatus according to the present embodiment. Here, FIG. 12A is a schematic perspective view of an image reading apparatus according to this configuration example, and FIG. 12B is a schematic cross-sectional view of the image reading apparatus. In addition, about the structure equivalent to embodiment mentioned above, the same code | symbol is attached | subjected and the description is simplified.

  In the above-described embodiment (see FIG. 1), the configuration in which the backlight 300 constituting the surface light source and the image display unit 200 including the transmissive liquid crystal pixel array 250P are applied is shown. It is not limited. That is, the object (finger) placed on the detection surface DTC on the image reading unit 100 (photosensor array 140P) is irradiated with light from the back side (the side opposite to the visual field side) of the image reading unit 100. It is sufficient if it has a configuration capable of. For example, as shown in FIGS. 12A and 12B, a display pixel array in which display pixels including light-emitting elements such as organic electroluminescence elements (organic EL elements) and light-emitting diodes are two-dimensionally arranged on an insulating substrate 410. The self-luminous image display unit (image display unit, surface light source, self-luminous display panel) 400 provided with 430 may be applied.

  Here, for example, in the case where a display pixel including an organic EL element is applied, as shown in FIGS. 12A and 12B, each surface of the insulating substrate 410 (upward in the drawing) An image display area is defined by a display pixel array 430 in which display pixels formed by an organic EL layer and an electrode layer (not shown) corresponding to the pixel area are two-dimensionally arranged. A display driving operation is controlled based on a control signal supplied from a display driving driver 420 disposed on the insulating substrate 410.

  According to the image reading apparatus provided with such a self-luminous image display unit, the display operation of desired image information and the image pattern of the subject in the image reading unit (by the light emitted from the image display unit) Both the fingerprint reading operation can be realized. Therefore, the backlight shown in the above-described embodiment (see FIG. 1), a control circuit for controlling the lighting of the backlight (light emission control), a power supply circuit, etc. The apparatus configuration of the image reading apparatus can be made smaller, lighter, and thinner, and power consumption can be significantly reduced.

[Second Embodiment]
Next, a second embodiment of the image reading apparatus and the image reading method according to the present invention will be described with reference to the drawings.
<Image reading device>
FIG. 13 is a main part configuration diagram illustrating an example of an image reading unit applied to the image reading apparatus according to the second embodiment. Here, about the structure equivalent to 1st Embodiment mentioned above, the same code | symbol is attached | subjected and the description is simplified.

  In the first embodiment described above, the case where the demonstration image is displayed prior to the fingerprint reading operation has been described. However, in the present embodiment, during the fingerprint reading operation, the light irradiating the finger (subject) is subjected to image reading. It is set so as to transmit through only the area corresponding to the row (reading area) in which the image reading operation is executed, not the entire area.

  In order to realize such a fingerprint reading operation, the image reading unit 100 (photosensor array 140P) applied to the image reading apparatus DVC according to the present embodiment is arranged for each row as shown in FIG. The arrangement relationship between the top gate line Lt that connects the top gate terminals TG of the photosensors PS in common and the bottom gate line Lb that connects the bottom gate terminals BG in common is the bottom gate line Lb on the side with the smaller row number. And a top gate line Lt on the side with the larger row number (scanning direction of the row in which the image reading operation is executed (indicated by an arrow in the figure); in other words, the rotational movement direction of the finger FG). It is comprised so that it may be arrange | positioned.

<Image Reading Method of Image Reading Apparatus>
Next, a fingerprint reading operation (image reading operation) in the image reading apparatus including the above-described image reading unit will be described.
FIG. 14 is a flowchart illustrating an example of a fingerprint reading operation in the image reading apparatus according to the present embodiment. FIG. 15 is a conceptual diagram showing a light irradiation state on the finger in the fingerprint reading operation in the image reading apparatus according to the present embodiment. Here, the description of the control operation equivalent to that of the first embodiment will be simplified.

  As shown in FIG. 14, the fingerprint reading operation in the image reading apparatus DVC according to the present embodiment is, as in the first embodiment (see FIG. 9) described above, first a predetermined demonstration prior to the fingerprint reading operation. An image is displayed on the image display unit 200 (step S201), and the user of the image reading apparatus DVC is made aware of the finger placement position, the rotational movement method, the approximate speed of the rotational movement, and the like in the fingerprint reading operation.

  Next, according to the demonstration image, the finger FG is placed on the start point area of the image reading area ARs set in the image reading unit 100 (step S202), and then an operation for starting a fingerprint reading operation is performed (step S202). S203), as shown in FIGS. 15A to 15C, a reading area (reading operation) from one side (right side of the drawing) to the other side (left side of the drawing) of the image reading area ARs in response to the rotational movement of the finger. The fingerprint reading operation (image reading operation) for reading the fingerprint is performed while scanning the line) (step S204).

  Here, in the fingerprint reading operation in step S204, an irradiation region (illumination region; guidance information) for irradiating light to the finger FG is a region including a row range corresponding to the charge accumulation time in the fingerprint reading operation (at least the reading operation). Is set as a minimum area, and the irradiation area is made to correspond to the rotational movement of the finger FG (actually displayed as a demonstration image). This corresponds to the finger moving method, the moving speed, etc., and is controlled so as to move sequentially (corresponding to the scanning control of the reading region RGs in the fingerprint reading operation).

  Here, in the image reading unit 100 including the photosensor array 140P illustrated in FIG. 13, the width of the white display region DSw in the image display unit 200 serving as the irradiation region (illumination region) is set by the above-described image reading operation. The width between the top gate line Lt and the bottom gate line Lb of each row is set to be the minimum unit width.

  Specifically, the irradiation area DSw is sequentially moved in accordance with the scanning control of the reading area RGs. Specifically, in the image display area ARi set in the image display unit 200, at least the reading area RGs is minimized. The white display area DSw is set corresponding to the area of the arbitrary range included as the area, and the other area of the image display area ARs is set as the black display area DSb.

  More specifically, the white display region DSw set in the image display unit 200 for irradiating a predetermined region of the subject (finger) during the image reading operation is a photo sensor of the image reading unit 100. In the array 140P, a reset state is set by applying a top gate pulse (reset pulse) to the top gate line Lt of a specific row (i row), and in synchronization with the end timing of the reset operation (or After the reset operation is completed, in the liquid crystal pixel array 250P of the image display unit 200, white display is started in an area corresponding to the i row, and a bottom gate pulse (readout pulse) is applied to the bottom gate line Lb. In synchronization with the start timing of the read operation set by (or before the start of the read operation), By terminating the white display in the serial image display unit 200, the charge accumulation period in each row of photosensors PS, i.e., the display period of a white display is set.

Then, by sequentially moving the white display area DSw corresponding to the scanning control of the reading area RGs, it is possible to read the fingerprint image favorably corresponding to the rotational movement of the finger FG.
Thus, only the vicinity of the area where the fingerprint is imaged (reading area RGs) is set to the white display state, and the finger FG is irradiated with light, so that the user of the image reading apparatus DVC can select the white display area DSw. The movement position of the finger FG makes it easy to recognize the placement position of the finger FG, the rotational movement speed, and the like, and can be used as a guide when the finger FG is rotationally moved.

  Therefore, prior to the fingerprint reading operation, a demonstration image is displayed in the image display area, and the white display area (irradiation area) is displayed at a predetermined moving speed in a predetermined scanning direction during the fingerprint reading operation. Thus, a wide range of fingerprint images (rotated fingerprint images) including the side surface of a finger having a curved surface can be satisfactorily read.

  Also, with respect to the white display area that moves in the predetermined scanning direction, each row top gate line of the photosensor array is disposed on the front side in the scanning direction, and the bottom gate line is disposed on the rear side in the scanning direction. Simple control of reset operation set by top gate pulse (reset pulse), read operation set by bottom gate pulse (read pulse), and execution timing of charge accumulation period set by these pulses By this method, it is possible to correspond to the movement timing of the white display area.

  In the present embodiment, the configuration of the image display unit may include a transmissive image display unit and a backlight, as shown in FIG. 1 in the first embodiment described above. As shown in FIG. 12, a self-luminous image display unit may be provided. Here, in the former configuration, it is necessary to continuously turn on the backlight during the fingerprint reading operation period. However, in the latter configuration, only the display pixels that perform the above-described white display region are caused to emit light. Therefore, power consumption in the image reading apparatus can be reduced.

[Third Embodiment]
Next, a third embodiment of the image reading apparatus and the image reading method according to the present invention will be described with reference to the drawings.
(Image reading device)
FIG. 16 is a principal block diagram showing a third embodiment of the image reading apparatus according to the present invention. Here, a configuration in which the image display unit is omitted from the image reading apparatus shown in the first embodiment described above is shown. Further, the same or equivalent reference numerals are assigned to the same components as those in the first embodiment, and the description thereof is simplified.

  As shown in FIG. 16, the image reading apparatus DVC according to the present embodiment includes an image reading unit 100, an image display unit 200 (not shown), and a backlight 300 that are the same as those in the first embodiment described above. And a system control unit 500 that exchanges data with an external function unit 600 provided outside the image reading apparatus DVC.

  Here, in FIG. 16, the A / D converter 150 provided in the image reading unit 100 includes a read data signal (data voltage Vrd) that is an analog signal read via the drain driver 130 </ b> D, which is a digital signal. An analog-to-digital converter (hereinafter abbreviated as “A / D converter”) for converting to gradation data (lightness data).

  The system control unit 500 controls at least the image pattern reading operation of the subject in the image reading unit 100, the generation control of image data (image information) based on the read data signal acquired by the image reading unit 100, and the lighting of the backlight 300. In addition to control (light emission control), control of data exchange with the external function unit 600 that executes predetermined image processing such as image data processing and collation, etc., and a read sensitivity adjustment operation described later are performed, A controller (reading sensitivity setting unit, image generation means) 510 having a function of setting an optimum reading sensitivity for a subject during a reading operation of an image pattern of the subject, and a gradation obtained by using as a work area of the controller 510 Data, image data, processing data related to photosensor reading sensitivity settings, etc. are temporarily saved ( And 憶) to RAM 520, and a, a ROM530 for holding the control program and control for various data of the controller 510.

  FIG. 17 is a schematic diagram illustrating a configuration example of a controller applied to the image reading apparatus according to the present embodiment. Here, only one configuration example of the controller necessary for executing the read sensitivity adjustment operation described later is shown, and the present invention is not limited to this configuration. In short, any other configuration may be used as long as it has a configuration necessary to execute a sensitivity adjustment operation for setting an appropriate reading sensitivity according to the subject.

  As shown in FIG. 17, for example, the controller 510 applicable to the image reading apparatus DVC according to this embodiment includes at least the control signals φtg, φbg, φpg to the top gate driver 120T, the bottom gate driver 120B, and the drain driver 130D. The device controller 511 that controls each operation state, and manages various data, and writes / reads data to / from the RAM 520 and ROM 530, and outputs data to the external function unit 600, etc. The controller 512, the controllers 511 and 512 are integrated according to a predetermined control program, and a main controller 513 that exchanges control signals with the external function unit 600, and functions as described below are provided. Data comparator 514, adder 515 Data selector 516, and a sensitivity adjustment control unit 517 and a backlight emission control unit 518.

The data comparator 514 performs the gradation of the subject image read while changing the reading sensitivity (that is, the above-described charge accumulation period) in the photosensors PS arranged in the photosensor array 140P in the sensitivity adjustment reading operation described later. For the data (brightness data), the maximum and minimum values excluding the saturation value are extracted by comparing the magnitude relationship between the gradation data at each reading sensitivity, and each reading sensitivity of the photosensor PS is determined by an adder 515 described later. The maximum value of the dynamic range (data range consisting of the difference between the maximum value and the minimum value of the gradation data) is extracted.
Further, the adder 515 calculates the dynamic range for each reading sensitivity from the difference between the maximum value and the minimum value of the gradation data in each reading sensitivity of the photosensor PS extracted by the data comparator 514, and the data Output to the selector 516.

  The data selector 516 includes gradation data input via the A / D converter 150, gradation data (dynamic range, etc.) processed via the data comparator 514 and the adder 515, and The processed data or the like is input, and these data are written to and read from the RAM 520 as necessary, or re-input to the data comparator 514 or the adder 515, or to the external function unit 600 via the data controller 512. Controls the switching of the output and other operations.

  The sensitivity adjustment control unit 517 determines the read sensitivity (charge accumulation period) of the photosensors PS arranged in the photosensor array 140P for each row based on the control signal from the data controller 512 during the sensitivity adjustment read operation. The timing of the control signals φtg, φbg, and φpg output from the device controller 511 to the top gate driver 120T, the bottom gate driver 120B, and the drain driver 130D is controlled so as to be changed stepwise. In addition, in the normal image reading operation (fingerprint reading operation) after the sensitivity adjustment reading operation, the optimum reading sensitivity selected based on the gradation data acquired by the sensitivity adjustment reading operation is the photosensor PS. The timing of each control signal φtg, φbg, φpg output from the device controller 511 is controlled so as to be set to.

  In addition, the backlight emission control unit 518 causes the backlight BL to emit light with a predetermined luminance at least in the sensitivity adjustment reading operation and the regular image reading operation based on the control signal from the main controller 513, and the photo sensor Control is performed to irradiate the subject (finger FG) placed on the detection surface DTC on the upper surface of the array 140P.

  As a result, the controller 510 outputs the control signals φtg, φbg, and φpg to the top gate driver 120T, the bottom gate driver 120B, and the drain driver 130D (precharge circuit unit 135), as shown in FIG. In the reset period, the top gate driver 120T applies a top gate pulse (reset pulse) φT to the top gate terminal TG of each photosensor PS. In the readout period, the bottom gate driver 120B outputs each photosensor PS. In the operation of applying the bottom gate pulse (readout pulse) φB to the bottom gate terminal BG of the photosensor and the precharge period, the precharge pulse is applied from the drain driver 130D (precharge circuit unit 135) to the drain terminal D of each photosensor PS. Each operation of applying (precharge voltage Vpg) is controlled.

  Then, the controller 510 detects the drain voltage VD (data voltage Vrd) corresponding to the amount of charge accumulated in each photosensor PS corresponding to the image pattern (fingerprint) of the subject by the sampling circuit unit 134, and the source follower is detected. It is converted into a digital signal via the circuit unit 133, the parallel-serial conversion circuit unit 132, and the A / D converter 150, and is input as gradation data. The controller 510 generates image data of the subject based on the gradation data, and executes writing to and reading from the RAM 520 or output to the external function unit 600, for example. The external function unit 600 may be any device that can perform arbitrary image processing and image display. For example, the external function unit 600 may be a personal computer or the like that has been widely used in recent years.

<Image Reading Method of Image Reading Apparatus>
Next, an image reading method (reading sensitivity adjustment operation, fingerprint reading operation) in the image reading apparatus according to the present embodiment will be described.
FIG. 18 is a flowchart illustrating an example of an image reading method in the image reading apparatus according to the present embodiment. FIG. 19 is a schematic view showing an example of guide display executed prior to the sensitivity adjustment reading operation in the image reading apparatus according to the present embodiment. Note that the series of image reading methods (reading sensitivity adjustment operations) shown below are merely examples applicable to the image reading apparatus according to the present invention, and the present invention is not limited to this method.

  The image reading method of the image reading apparatus DVC according to the present embodiment is roughly divided into each row arranged in the photosensor array 140P at an arbitrary timing prior to a normal subject image reading operation (fingerprint reading operation) on the subject (finger). The sensitivity adjustment reading operation for reading the image pattern (fingerprint image) of the subject by changing the reading sensitivity for each photosensor, and the image of the subject based on the gradation data acquired by the sensitivity adjustment reading operation Using the read sensitivity adjustment operation including the optimum sensitivity derivation operation for extracting the optimum read sensitivity (charge accumulation period) corresponding to the pattern, surface characteristics, use environment of the image reading device DVC, etc., and using the extracted optimum read sensitivity The above-described control is performed so as to sequentially execute a normal subject image reading operation (fingerprint reading operation) for reading the subject image pattern. It controls each component of the image reading apparatus DVC by 510. Here, a series of processing procedures shown below is realized by, for example, loading a control program stored in advance in the ROM 530 into the RAM 520 and executing it by the controller 510.

  In the processing operation by the controller 510 according to the present embodiment, the sensitivity adjustment reading operation, the optimum sensitivity derivation operation, and the normal subject image reading operation described above are sequentially executed. First, as shown in FIG. Prior to the reading operation, the image display unit 200 executes the sensitivity adjustment reading operation on the image display area ARi prior to the image reading operation (fingerprint reading operation) of the subject (finger FG), and for the sensitivity adjustment. An operation for displaying (notifying) the placement position, placement method, and the like of the subject in the reading operation using guide information including character information and image information and causing the user of the image reading apparatus DVC to recognize the information (step S311). As a method for recognizing the sensitivity adjustment reading operation in advance, in addition to the display in the image display area ARi described above, notification is made by voice information, vibration of the device in which the image reading device DVC is mounted, or the like. Also good.

  Here, the guide display relating to the sensitivity adjustment reading operation displayed in the image display area ARi is, for example, as shown in FIGS. 19A and 19B, a rectangular sensitivity adjustment reading area RGa (not shown). For convenience, it is hatched for convenience) and the subject image FGi may be displayed over the area so as to recognize the subject placement state (finger tilt state, etc.) Only the reading area RGa may be displayed, and information such as text information or voice information (not shown) may be used to notify the subject to be placed in close contact with the reading area RGa, or the reading area RGa may be displayed. Instead, only the subject image may be displayed.

  Further, as shown in FIG. 19A, the sensitivity adjustment reading area RGa displayed in the image display area ARi is an end area of the image reading area ARs (for example, an end area serving as a starting point of a fingerprint reading operation). ), Or as shown in FIG. 19B, may be arranged in any other region (for example, the central region of the image reading area ARs). Good.

  Next, the user places the subject (finger) on the detection surface DTC on the reading region RGa in the image reading area ARs based on the guide display (sensitivity adjusting reading region RGa) related to the sensitivity adjustment reading operation. Thereafter, for example, by performing an operation such as pressing a switch for starting a sensitivity adjustment reading operation, a series of sensitivity adjustment operations as described below are executed.

  First, in the sensitivity adjustment read operation, the operation mode of the read sensitivity adjustment operation is set in the device controller 511 by the main controller 513, and the sensitivity adjustment control unit 517 via the data controller 512 performs the sensitivity adjustment read operation. Reading sensitivity is set.

  As a result, the control signals φtg, φbg, and φpg are supplied from the device controller 511 to the top gate driver 120T, the bottom gate driver 120B, and the drain driver 130D, thereby being placed on the detection surface DTC of the photosensor array 140P. An operation of reading an image of the subject (finger FG) with a predetermined reading sensitivity is executed (S101).

  Specifically, the reading sensitivity is set so as to be gradually different for each row or every plurality of rows in the sensitivity adjustment reading region RGa set in the photosensor array 140P, as shown in FIG. In addition, by sequentially driving the photosensors PS for each row, a sensitivity adjustment reading operation for reading a single subject with a plurality of different reading sensitivities is executed (S301). A specific example of the reading sensitivity setting method applied to the sensitivity adjustment reading operation will be described later in detail.

  Then, the data voltage Vrd taken into the drain driver 130D from each photosensor PS of the photosensor array 140P by such a sensitivity adjustment reading operation is converted into gradation data consisting of a digital signal via the A / D converter 150. For example, the data is converted into the controller 510 and stored in the RAM 170 directly via the data selector 516 or once input to the data comparator 514.

  Next, in the optimum sensitivity deriving operation, from the photosensor PS for each reading sensitivity (that is, for example, for each row) among the gradation data acquired by the data controller 512 via the data selector 516 in step S301. The obtained gradation data is extracted and read into the data comparator 514 (S302), the gradation data is compared for each reading sensitivity, and the largest gradation data (corresponding to the brightest gradation) is obtained. ) And the minimum gradation data (corresponding to the darkest gradation) are extracted (S303).

  Then, the adder 515 controlled by the data controller 512 calculates the difference between the maximum value and the minimum value of the gradation data extracted for each reading sensitivity, that is, the dynamic range (data range of the gradation data) ( In step S304, the result is temporarily stored in the RAM 520 via the data selector 516. Such a dynamic range calculation process is sequentially executed for each reading sensitivity.

  Next, the dynamic range for each reading sensitivity stored in the RAM 520 is read into the data comparator 514 via the data selector 516, and, for example, the reading sensitivity at which the dynamic range becomes the maximum from the change tendency of the dynamic range with respect to the reading sensitivity. Is extracted (S305).

  Thereby, the main controller 513 determines that the extracted reading sensitivity is the optimum reading sensitivity (charge accumulation period) that can obtain a good contrast corresponding to the image pattern of the subject (finger FG) ( S306). A specific example of the optimum reading sensitivity derivation method applied to the optimum sensitivity derivation operation will be described in detail later.

  Then, when the reading sensitivity adjustment operation for the subject, which consists of the above-described series of sensitivity adjustment reading operations and optimum sensitivity deriving operations, is completed, as shown in FIG. 18, the image display unit 200 displays the image display area ARi. The fact that the reading sensitivity adjustment operation has been completed may be displayed (notified) by guide information made up of character information and image information so that the user of the image reading device DVC can recognize it or enter the image display area ARi. In addition to the above display, notification may be made by sound information, vibration of a device in which the image reading device DVC is mounted, or the like (step S312).

  Next, as shown in FIG. 18, prior to the regular subject image reading operation, the subject (finger FG) is placed in the image display area ARi by the image display unit 200 in the same manner as in the first embodiment (see FIG. 10). ) Image reading operation (fingerprint reading operation), the mounting position of the subject on the image reading area ARs in the subject image reading operation, the rotational movement method, the approximate speed of the rotational movement, and the like are used. A demonstration image that can be recognized by the person is displayed (step S313).

  After that, the main controller 513 sets the operation mode of the normal subject image reading operation (fingerprint reading operation) in the device controller 511, and the reading sensitivity adjustment operation described above has the optimum reading sensitivity in the photosensor PS. The read sensitivity (charge accumulation period) is set in the sensitivity adjustment control unit 517 via the data controller 512, whereby each control signal is sent from the device controller 511 to the top gate driver 120T, the bottom gate driver 120B, and the drain driver 130D. φtg, φbg, and φpg are supplied, and a subject image reading operation for reading the image of the subject (finger FG) placed on the detection surface DTC with the optimum reading sensitivity is executed (S307).

  Here, the subject image reading operation (fingerprint reading operation) executed in step S307 is the image reading area ARs (detection surface DTC) provided in the image reading unit 100 as shown in the first embodiment. The photosensor array 140P is sequentially read by sequentially reading an image of a region (reading region RGs) in which the subject is in close contact with the detection surface DTC while rotating the subject (finger FG) based on the above-described demonstration image. With only scanning control for one screen, a wide range of fingerprint images including the side surface of a subject (finger) having a curved surface can be acquired quickly and satisfactorily while suppressing the occurrence of imaging errors.

  In the present embodiment, the demonstration image display operation related to the subject image reading operation, which is executed prior to the normal subject image reading operation (fingerprint reading operation), is performed after the reading sensitivity adjustment operation is completed. However, the present invention is not limited to this, and may be executed prior to the read sensitivity adjustment operation, for example.

  In this embodiment, the case where the normal subject image reading operation is executed after the reading sensitivity adjustment operation is executed has been described. However, the present invention is not limited to this, and for example, the reading sensitivity adjustment operation is performed. Without performing the above, a normal subject image reading operation is executed by applying a predetermined reading sensitivity, and an error occurs in image processing (for example, fingerprint matching processing) of image data acquired by the subject image reading operation. If it occurs, a read sensitivity adjustment operation (including display of guide information related to the sensitivity adjustment read operation and a notification operation) may be executed, and a normal subject image read operation may be urged again.

(Sensitivity adjustment reading operation)
Here, the sensitivity adjustment reading operation (step S301) will be specifically described.
FIG. 20 is a timing chart illustrating an example of a reading sensitivity (charge accumulation period) setting method applied to the sensitivity adjustment reading operation according to the present embodiment. Here, the drive control method (see FIG. 7) in the above-described photosensor (double gate type photosensor) is referred to as appropriate.

  FIG. 20 shows a method of setting different reading sensitivities in stages for all rows or specific rows of the sensitivity adjustment reading region RGa set in the image reading area ARs in the sensitivity adjustment reading operation described above. First, the top gate pulse (reset pulse) φT1, φT2,... ΦTn is simultaneously applied from the top gate driver 120T simultaneously to each of the photosensors PS constituting the photosensor array 140P to perform the reset operation. After executing the charge accumulation periods T1, T2,..., Tn of the photosensors PS in all the rows all at once, the precharge signal φpg applied to the photosensors PS for each row from the drain driver 130D, and the bottom Bottom gate pulse (readout pulse) φB1 applied from the gate driver 120B, By setting B2,..., ΦBn to be shifted step by step by a predetermined time interval (delay time Tdly), the timing of the precharge operation and the read operation in the photosensor PS for each row is sequentially changed, and for each row. The set charge accumulation periods (reading sensitivity) T1, T2,..., Tn are controlled so as to be mutually changed at the time interval (Tdly).

  Thereby, in the sensitivity adjustment reading operation, the subject image is read once (for one screen) for each row (may be all rows as described above, or may be a specific row). Gradation data can be acquired with different reading sensitivities (that is, different reading sensitivities for the number of rows).

  Note that the method of setting the reading sensitivity (charge accumulation period) applied to the image reading method (sensitivity adjustment reading operation) of the image reading apparatus DVC according to the present invention is not limited to the above-described method, and at least If the image pattern of the subject can be read with different reading sensitivities and gradation data can be obtained for each reading sensitivity, for example, after reading the subject image in the reading area with a single reading sensitivity, the reading sensitivity is changed. Of course, the operation of reading the subject image in the reading area again may be repeated a plurality of times, and it is needless to say that another method may be used.

(Optimal sensitivity derivation operation)
Next, the above-described optimum sensitivity deriving operation (steps S302 to S306) will be specifically described.
FIG. 21 is a graph showing an example of a change in gradation data obtained by the sensitivity adjustment reading operation according to the present embodiment. FIG. 22 is an optimum graph applicable to the reading sensitivity adjustment operation according to the embodiment. It is a conceptual diagram which shows an example of the deriving method of reading sensitivity.

  When the reading sensitivity setting method as described above is applied and the reading sensitivity set in the photosensor PS is changed for each row and the image pattern (fingerprint) of the subject is read, the reading sensitivity is set in a specific row (reading sensitivity). The change in the gradation data is shown as shown in FIGS. 21 (a) to 21 (e), for example. In FIG. 21, between the gradation data observed in the white part of the subject (that is, the maximum value in the bright state) and the gradation data observed in the black part (the maximum value in the dark state), for example, 256 An example of a change in gradation data in an arbitrary row (for example, the 80th, 104th, 128th, 152th, and 176th rows) in the sensitivity adjustment reading region RGa set in the photosensor array 140P. Indicated.

  The change in the gradation data in each row (reading sensitivity) is as shown in FIGS. 21A to 21C in the row where the reading sensitivity, that is, the charge accumulation period is set to be relatively short. The entire image (fingerprint image) is read as a substantially dark state, and the difference between the maximum value and the minimum value (dynamic range) of the gradation data in the row is saturated on the black side (gradation data “0” side) Since it becomes the state which became, it becomes a small numerical value. Although not shown, in the row where the charge accumulation period is set to be relatively long, the entire fingerprint image is read as a substantially bright state, and the difference between the maximum value and the minimum value of the gradation data in the row is the maximum. Since the value is saturated on the white side (tone data “255” side), the value is also small.

On the other hand, as shown in FIGS. 21D and 21E, in the region where the contrast (brightness difference) of the subject image (fingerprint image) is relatively clear, the maximum value and the minimum value of the gradation data The difference (dynamic range) indicates a large numerical value.
Therefore, by extracting the maximum value and the minimum value of the gradation data for each row (each reading sensitivity) and calculating the dynamic range from the difference, as shown in FIGS. In the area where the number is small and the area where the row number is large, the dynamic range is calculated to be small.On the other hand, in the intermediate area of the row number, the contrast becomes clear, so that the dynamic range is calculated to be large. Show.

  In such a dynamic range change tendency, as shown in FIG. 22A, when the dynamic range shows the maximum value MA1 in a specific row RCa (for example, the 176th row), it is shown in FIG. By referring to the correlation table between the maximum and minimum values of the gradation data for each row number, the dynamic range, and the reading sensitivity (charge accumulation period) set for the row, the row with the maximum dynamic range (176 rows) The reading sensitivity (T176) set to (Eye) is extracted and set as the optimum reading sensitivity in the photosensor (light receiving sensitivity characteristic).

  Therefore, by applying such read sensitivity adjustment operation, the image pattern of the subject is read with a plurality of different read sensitivities, and the read sensitivity with the highest contrast (maximum dynamic range) among the respective read sensitivities is obtained. In the normal subject image reading operation (fingerprint reading operation), the image pattern of the subject can be read using the extracted reading sensitivity (optimum reading sensitivity), so that the wetness of the finger that is the subject and the fingerprint Appropriate reading sensitivity can be set as appropriate depending on the size of the unevenness of the device and the use environment of the device when performing the fingerprint reading operation, and a fingerprint image with good contrast can be read at all times. Thereby, a system with a small authentication error at the time of fingerprint authentication processing can be constructed. In this case, for example, even in a relatively dark usage environment, the reading sensitivity can be appropriately adjusted and set according to the situation, so there is no need to increase the light emission luminance of the backlight. An increase in power consumption in the reading device (fingerprint reading device) can also be suppressed.

[Fourth Embodiment]
Next, an image reading apparatus and an image reading method according to a fourth embodiment of the invention will be described with reference to the drawings.
<Image reading device>
FIG. 23 is a schematic view showing a fourth embodiment of the image reading apparatus according to the present invention. Here, FIG. 23A is a diagram showing a planar spread of the image reading area and the image display area in the image reading apparatus according to the present embodiment, and FIGS. 1 is a schematic configuration diagram of an image reading apparatus according to an embodiment. In FIG. 23, the driver provided on the insulating substrate is omitted. FIG. 24 is a schematic diagram showing the relationship between the image reading area and the image display area when the size of the insulating substrate is set to be equal in the image reading apparatus according to the present embodiment. In addition, about the structure equivalent to 1st Embodiment mentioned above, the same code | symbol is attached | subjected and the description is simplified. Here, the backlight is omitted.

  In the image reading apparatus DVC according to the present embodiment, as shown in FIG. 23A, the image display area ARi set in the image display unit 200 is at least the image reading area ARs set in the image reading unit 100. (For convenience of illustration, it is indicated by hatching for convenience), and a planar spread is set so as to have a wider area than the image reading area ARs. Here, for example, as shown in FIG. 23A, the image display area ARi is set so as to protrude from a specific one side (upper side in the drawing) of the rectangular image reading area ARs. In the protruding image display area ARg, various guide information (character information, image information, etc .; guidance information) related to at least the above-described image reading operation (including the reading sensitivity setting operation) can be displayed. It is configured. Hereinafter, the image display area ARg that protrudes from the image reading area ARs is referred to as a “guide display area”.

  As a configuration for realizing such planar expansion of the image display area ARi and the image reading area ARs, for example, as shown in FIG. 23B, an insulating substrate 110 of the image reading unit 100, The configuration in which the image reading area ARs is set smaller than the image display area ARi while the size of the insulating substrate 210 of the image display unit 200 is made equal, or the insulating property of the image reading unit 100 as shown in FIG. A configuration in which the substrate 110 is set smaller than the size of the insulating substrate 210 of the image display unit 200 can be applied.

  According to such an image reading apparatus, when the configuration shown in FIG. 23B is applied, the information displayed in the guide display area ARg of the image display area ARi is arranged on the visual field side. It passes through the insulating substrate 110 of the image reading unit 100 and is visually recognized by the user. When the configuration shown in FIG. 23C is applied, the information displayed in the guide display area ARg of the image display area ARi is directly visible by the user.

  As shown in FIG. 23B, in the configuration in which the size of the insulating substrate 110 of the image reading unit 100 and the size of the insulating substrate 210 of the image display unit 200 are set equal, the guide display area The guide information displayed on the ARg is visually recognized by the user through the insulating substrate 110 of the image reading unit 100 arranged on the visual field side, but on the visual field side of the guide display area ARg. For example, as shown in FIG. 24A, only the transparent insulating substrate 110 on which the photosensor array 140P (image reading area ARs) is not formed is provided in the image reading 100 unit arranged in FIG. As shown in FIG. 24B, the top gate line Lt, the bottom gate line Lb, and the gate are formed on the surface of the insulating substrate 110 in the same manner as the image reading area ARs. Line Ld, the photo sensor array 140P equivalent structure consisting of a photosensor PS and the like, or may be one single configuration at least one of the photosensor array 140P is formed. However, in the latter configuration, the photosensor PS and various wirings provided in the image reading unit 100 (photosensor array 140P) in the area corresponding to the guide display area ARg are dummy (dummy pixels, Dummy wiring).

<Image Reading Method of Image Reading Apparatus>
Next, a fingerprint reading operation (image reading operation) in the image reading apparatus having the above-described configuration will be described.
FIG. 25 is a conceptual diagram showing a method for guiding the rotational movement of the finger in the fingerprint reading operation in the image reading apparatus according to the present embodiment. Here, the description of the control operation equivalent to each of the above-described embodiments is simplified.

  In the fingerprint reading operation in the image reading apparatus DVC according to the present embodiment, as in the first embodiment (see FIG. 9), first, a demonstration image in which the finger FG is rotated is moved before the fingerprint reading operation. The information is displayed on the display unit 200 so that the user of the image reading apparatus DVC can recognize the placement position of the finger FG, the rotational movement method, the approximate speed of the rotational movement, and the like in the fingerprint reading operation.

  Next, on the basis of the demonstration image described above, the finger FG is placed on the start point area of the image reading area ARs set in the image reading unit 100, and then an operation for starting the fingerprint reading operation is performed. Here, as shown in FIG. 25A, guide information SIN for recognizing the start point area is displayed in the guide display area ARg at a position corresponding to the start point area of the image reading area ARs on which the finger is placed. . Here, as shown in FIG. 25A, the guide information SIN displayed in the guide display area ARg is character information (“imaging area” in the figure) for describing the fingerprint reading area RGs, an illustration, and the like. It may be an indicator-like display in which a mark or a light emitting area expands or contracts corresponding to the rotational movement of a finger.

  Next, as shown in FIGS. 25A to 25C, guide display is performed in accordance with the moving speed of scanning the reading region RGs from one side (right side of the drawing) to the other side (left side of the drawing) of the image reading area ARs. By moving the guide display SIN displayed in the area ARg, the user is made to recognize the placement position (reading area) of the finger FG and keep the finger FG in close contact with the reading area RGs while rotating the finger FG. Read the fingerprint.

This allows the user of the image reading apparatus to recognize the finger placement position with simple operation control that displays guide information in the guide display area corresponding to the area (reading area) where the fingerprint is imaged. As a result, the finger can be appropriately brought into close contact with the reading area while rotating the finger, and a wide range of fingerprint images including the side surface of the finger having a curved surface can be read favorably while suppressing imaging errors. .
Also in the present embodiment, the configuration of the image display unit may include a transmissive image display unit and a backlight, as shown in FIG. 1, or as shown in FIG. A self-luminous image display unit may be provided.

1 is an overall configuration diagram showing a first embodiment of an image reading apparatus according to the present invention. FIG. 3 is a main part configuration diagram illustrating an example of an image display unit applied to the image reading apparatus according to the first embodiment. FIG. 3 is a main part configuration diagram illustrating an example of an image reading unit applied to the image reading apparatus according to the first embodiment. It is a schematic sectional drawing which shows the element structure of the photosensor applicable to the image reading part which concerns on 1st Embodiment. FIG. 3 is a schematic block diagram illustrating a configuration example of a top gate driver or a bottom gate driver applicable to the image reading unit according to the first embodiment. FIG. 2 is a schematic block diagram illustrating a configuration example of a drain driver applicable to the image reading unit according to the first embodiment. 6 is a timing chart illustrating an example of a drive control method in the image reading unit according to the first embodiment. FIG. 5 is a conceptual diagram illustrating an image reading operation when a fingerprint is read in the image reading unit according to the first embodiment. 5 is a flowchart illustrating an example of an overall operation when a fingerprint is read in the image reading apparatus according to the first embodiment. 6 is a schematic diagram illustrating an example of a demonstration display executed prior to an operation of reading a fingerprint in the image reading apparatus according to the first embodiment. FIG. FIG. 5 is a conceptual diagram illustrating a rotational movement of a finger in an operation of reading a fingerprint in the image reading apparatus according to the first embodiment. It is a whole block diagram which shows the other example of the image reading apparatus which concerns on 1st Embodiment. It is a principal part block diagram which shows an example of the image reading part applied to the image reading apparatus which concerns on 2nd Embodiment. 10 is a flowchart illustrating an example of a fingerprint reading operation in the image reading apparatus according to the second embodiment. FIG. 9 is a conceptual diagram illustrating a light irradiation state on a finger in a fingerprint reading operation in the image reading apparatus according to the second embodiment. It is a principal part block diagram which shows 3rd Embodiment of the image reading apparatus which concerns on this invention. It is the schematic which shows one structural example of the controller applied to the image reading apparatus which concerns on 3rd Embodiment. 10 is a flowchart illustrating an example of an image reading method in an image reading apparatus according to a third embodiment. FIG. 10 is a schematic diagram illustrating an example of guide display executed prior to a sensitivity adjustment reading operation in an image reading apparatus according to a third embodiment. 12 is a timing chart illustrating an example of a method for setting reading sensitivity (charge accumulation period) applied to a sensitivity adjustment reading operation according to the third embodiment. It is a graph which shows an example of the change of the gradation data obtained by the read operation for sensitivity adjustment concerning a 3rd embodiment. It is a conceptual diagram which shows an example of the derivation method of the optimal reading sensitivity applicable to the reading sensitivity adjustment operation | movement which concerns on 3rd Embodiment. It is the schematic which shows 4th Embodiment of the image reading apparatus which concerns on this invention. FIG. 10 is a schematic diagram illustrating a relationship between an image reading area and an image display area when the size of an insulating substrate is set to be equal in an image reading apparatus according to a fourth embodiment. FIG. 10 is a conceptual diagram illustrating a method for guiding rotation of a finger in a fingerprint reading operation in an image reading apparatus according to a fourth embodiment. It is a schematic block diagram which shows an example of the fingerprint reader in a prior art.

Explanation of symbols

DVC image reading device 100 image reading unit 110 insulating substrate 120 scanning driver 130 reading driver 140 reading pixel array 200 image display unit 210 insulating substrate 220 counter substrate 230 display driver driver 250 display pixel array 300 backlight ARi image display area ARs Image reading area RGs Reading area

Claims (3)

An image display unit comprising a display pixel array in which a plurality of display pixels are two-dimensionally arranged;
A fingerprint pattern of a finger that is arranged on the visual field side of the display pixel array and includes a transmissive read pixel array in which a plurality of read pixels are two-dimensionally arranged, and that rotates and moves on a detection surface provided on the read pixel array An image reading unit for reading
When reading the fingerprint pattern, a guide image as guide light for guiding the rotational movement of the finger is displayed on the display pixel array of the image display unit, with the display position of the guide image corresponding to the reading position of the fingerprint pattern. A display control unit to display to change ,
With
The reading pixel receives the reflected light of the guide light emitted from the image display unit and irradiated on the finger rotating and moving on the detection surface via the reading pixel array, and the fingerprint pattern of the finger An image reading apparatus, wherein the image reading apparatus is a photosensor that reads light and dark information . The image reading apparatus according to claim 1 , wherein the display pixel array is a transmissive liquid crystal display panel in which liquid crystal pixels are two-dimensionally arranged . The display pixel array is a self-luminous display panel in which the display pixels including light emitting elements are two-dimensionally arranged, and light emitted from the display panel is transmitted to the visual field side through the reading pixel array. The image reading apparatus according to claim 1 , wherein the image reading apparatus is configured as described above.

Images