WO2019228470A1 - 指纹检测装置和指纹检测方法 - Google Patents

指纹检测装置和指纹检测方法 Download PDF

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Publication number
WO2019228470A1
WO2019228470A1 PCT/CN2019/089336 CN2019089336W WO2019228470A1 WO 2019228470 A1 WO2019228470 A1 WO 2019228470A1 CN 2019089336 W CN2019089336 W CN 2019089336W WO 2019228470 A1 WO2019228470 A1 WO 2019228470A1
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Prior art keywords
circuit
analog
signal
sub
fingerprint detection
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PCT/CN2019/089336
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English (en)
French (fr)
Inventor
丁小梁
董学
王海生
刘英明
刘伟
王佳斌
李扬冰
王鹏鹏
张平
邓立凯
陈博
Original Assignee
京东方科技集团股份有限公司
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Priority to US16/622,557 priority Critical patent/US11308727B2/en
Publication of WO2019228470A1 publication Critical patent/WO2019228470A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1318—Sensors therefor using electro-optical elements or layers, e.g. electroluminescent sensing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith
    • H04N25/71—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
    • H04N25/75—Circuitry for providing, modifying or processing image signals from the pixel array
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2218/00—Aspects of pattern recognition specially adapted for signal processing
    • G06F2218/02—Preprocessing
    • G06F2218/04—Denoising

Definitions

  • the present disclosure relates to the field of fingerprint detection, and in particular, to a fingerprint detection device and a fingerprint detection method.
  • a photodiode is provided in each pixel.
  • the difference between the valleys of the fingerprints causes different reflections of the light shining on the fingerprints, which makes the light intensity sensed at the photodiodes different.
  • the fingerprint valley can be detected.
  • the present disclosure provides a fingerprint detection device including a detection substrate and a signal converter.
  • the detection substrate includes a plurality of pixels arranged in multiple rows and columns, and each pixel includes an induction circuit.
  • the induction circuit structure In order to receive an optical signal and output an induced electrical signal based on the received optical signal, the signal converter includes a plurality of analog-to-digital converters, and each analog-to-digital converter is connected to a column of induction circuits.
  • the fingerprint detection device further includes a control circuit, the control circuit is connected to the induction circuit and the analog-to-digital converter, and is configured to obtain an induction output from an induction circuit of at least a part of the plurality of pixels.
  • a common-mode component of the electrical signal and providing information about the common-mode component to the plurality of analog-to-digital converters, and
  • the analog-to-digital converter is configured to perform analog-to-digital conversion on a difference between an induced electrical signal from a corresponding induction circuit and the common-mode signal.
  • the analog-to-digital converter includes a signal input and a reference
  • the control circuit is configured to provide information about the common-mode component to the signal input and the reference of the analog-to-digital converter.
  • One of them makes the difference between the signal input terminal of the analog-to-digital converter and the signal received at the reference terminal equal to the difference between the induced electrical signal of the corresponding induction circuit and the common-mode signal.
  • a signal input terminal of each analog-to-digital converter is connected to an output terminal of each inductive circuit in a corresponding column
  • the control circuit includes: a comparison sub-circuit configured to acquire in a first fingerprint detection sub-period At least part of the inductive electrical signal output by the inductive circuit, and outputting the smallest one of the obtained inductive electrical signals as a reference signal; a plurality of switch sub-circuits corresponding to the plurality of analog-to-digital converters, the switches A first input terminal of the circuit is connected to an output terminal of the comparison sub-circuit, and an output terminal of the switch sub-circuit is connected to a reference terminal of a corresponding analog-to-digital converter; and a first control sub-circuit is configured to connect the second fingerprint In the detection sub-period, the first input terminal and the output terminal of each switching sub-circuit are controlled to be turned on to output the reference signal, wherein the second fingerprint detection sub-cycle is after the first fingerprint detection sub-cycle.
  • the second input terminal of the switching sub-circuit is grounded, and the first control sub-circuit is further configured to control the second input terminal and the output terminal of each switching sub-circuit in the first fingerprint detection sub-period.
  • a signal input terminal of each analog-to-digital converter is connected to an output terminal of each inductive circuit in a corresponding column, and a reference terminal of each analog-to-digital converter is grounded;
  • the control circuit includes: a plurality of serially connected in series Capacitors, two ends of each capacitor are respectively connected to the output ends of two adjacent induction circuits; a plurality of switching transistors corresponding to the plurality of induction circuits, a first pole of the switching transistor and an output of the corresponding induction circuit And the second pole of the switching transistor is connected to ground; and a second control sub-circuit connected to the control pole of each switching transistor, the second control sub-circuit is configured to be a switch during the first fingerprint detection sub-period.
  • the control electrode of the transistor provides an off signal; and the on signal of the switching transistor is provided in a second fingerprint detection sub-period, and the start time of the second fingerprint detection sub-period is in the first fingerprint detection sub-period. After the start time.
  • the fingerprint detection device further includes a calculation circuit, which is connected to each analog-to-digital converter and is configured to determine the output of any two adjacent induction circuits according to the output signal of each analog-to-digital converter. The difference between the induced electrical signals is determined based on the difference between the induced electrical signals output by any two adjacent induction circuits.
  • the induction circuit includes: a photodiode whose anode is connected to a low-level signal terminal; a first transistor whose control electrode is connected to a reset terminal of the induction circuit; the first electrode is connected to a high level The signal terminal is connected, and the second electrode is connected to the cathode of the photodiode; the second transistor has a control electrode connected to the cathode of the photodiode, and the first electrode is connected to the high-level signal terminal; the third transistor is The control electrode is connected to the scanning terminal of the induction circuit, the first electrode is connected to the second electrode of the second transistor, and the second electrode is connected to the output terminal of the induction circuit; the output terminal of each induction circuit is connected to a current source Connected.
  • the signal converter further includes a plurality of amplifiers connected to the analog-to-digital converters in a one-to-one correspondence, and an output terminal of the amplifier is connected to a signal input terminal of the corresponding analog-to-digital converter.
  • the input terminal of the amplifier is connected to the output terminal of the induction circuit of the corresponding column.
  • the comparison sub-circuit obtains only the inductive electrical signal output by the inductive circuit in the area covered by the fingerprint on the detection substrate, and outputs the smallest one of the obtained inductive electrical signals as the reference signal. .
  • the comparison sub-circuit obtains the pixel with the lowest brightness by detecting the brightness of each sub-pixel, and outputs the induced electrical signal output by the induction circuit in the obtained pixel as the reference signal.
  • the present disclosure also provides a fingerprint detection method for use in a fingerprint detection device.
  • the fingerprint detection device includes a detection substrate and a signal converter.
  • the detection substrate includes a plurality of pixels arranged in multiple rows and columns. Each pixel includes an induction circuit configured to receive an optical signal and output an induced electrical signal based on the received optical signal;
  • the signal converter includes a plurality of analog-to-digital converters, and each analog-to-digital converter is connected A list of said induction circuits,
  • the fingerprint detection method includes:
  • the analog-to-digital converter performs analog-to-digital conversion on the difference between the induced electrical signal from the corresponding induction circuit and the common-mode signal.
  • the analog-to-digital converter includes a signal input terminal and a reference terminal
  • providing information about the common-mode component to the plurality of analog-to-digital converters includes: providing information about the common-mode component One of a signal input terminal and a reference terminal of the analog-to-digital converter, so that the difference between the signal input terminal of the analog-to-digital converter and the signal received by the reference terminal is equal to the induced electrical signal of the corresponding inductive circuit and The difference between the common mode signals is described.
  • a signal input terminal of each analog-to-digital converter is connected to an output terminal of each induction circuit in a corresponding column, and the control circuit includes a comparison sub-circuit, a switch sub-circuit, and a first control sub-circuit,
  • Acquiring a common mode component of an induced electrical signal output by an induction circuit of at least a part of the plurality of pixels through a control circuit, and providing information about the common mode component to the plurality of analog-to-digital converters includes:
  • the inductive electrical signal output by at least part of the inductive circuit is obtained through a comparison sub-circuit, and the smallest one of the acquired inductive electrical signals is provided as a reference signal to the switching sub-circuit;
  • the first control sub-circuit is used to control the switch sub-circuit to provide the reference signal to a reference end of a corresponding analog-to-digital converter.
  • the second fingerprint detection sub-period is After the first fingerprint detection sub-cycle is described.
  • the first control sub-circuit controls the switch sub-circuit to provide a ground signal to a reference terminal of a corresponding analog-to-digital converter.
  • a signal input terminal of each analog-to-digital converter is connected to an output terminal of each induction circuit in a corresponding column, and a reference terminal of each analog-to-digital converter is grounded;
  • the control circuit includes: a plurality of capacitors connected in series in sequence, and two ends of each capacitor are respectively connected to the output ends of two adjacent induction circuits; a plurality of switching transistors corresponding to the plurality of induction circuits one by one, and the switching transistors
  • the first pole of the switch is connected to the output terminal of the corresponding induction circuit, the second pole of the switching transistor is grounded, and the second control sub-circuit is connected to the control pole of each switching transistor,
  • Acquiring a common mode component of an induced electrical signal output by an induction circuit of at least a part of the plurality of pixels through a control circuit, and providing information about the common mode component to the plurality of analog-to-digital converters includes: A fingerprint detection sub-cycle, which provides a turn-off signal for the control electrode of the switching transistor through a second control sub-circuit; and a second fingerprint detection sub-cycle, which provides an turn-on signal for the control electrode of the switching transistor through the second control sub-circuit, said The start time of the second fingerprint detection sub-cycle is after the start time of the first fingerprint detection sub-cycle.
  • the fingerprint detection device further includes a calculation circuit
  • the fingerprint detection method further includes:
  • the calculation circuit judges the difference between the induction electric signals output by any two adjacent induction circuits according to the output signals of each analog-to-digital converter, and determines the fingerprint image according to the difference between the induction electric signals output by any two adjacent induction circuits.
  • the comparison sub-circuit obtains only the inductive electrical signal output by the inductive circuit in the area covered by the fingerprint on the detection substrate, and outputs the smallest one of the obtained inductive electrical signals as the reference signal. .
  • the comparison sub-circuit obtains the pixel with the lowest brightness by detecting the brightness of each sub-pixel, and outputs the induced electrical signal output by the induction circuit in the obtained pixel as the reference signal.
  • FIG. 1 is a schematic diagram of a circuit structure of a conventional fingerprint detection device
  • FIG. 2 is a waveform diagram of a signal received by a conventional analog-to-digital converter
  • FIG. 3 is a schematic circuit diagram of a fingerprint detection device according to an embodiment of the present disclosure.
  • FIG. 4 is a schematic diagram showing connections between an induction circuit, a control circuit, and a signal converter in a fingerprint detection device according to an embodiment of the present disclosure
  • FIG. 5 is a schematic diagram illustrating connections between an induction circuit, a control circuit, and a signal converter in a fingerprint detection device according to an embodiment of the present disclosure.
  • a fingerprint detection device determines fingerprint information based on an electrical signal generated by a photodiode
  • the electrical signal needs to be analog-to-digital converted first.
  • the method is to amplify the electric signal and output it directly to the input end of the analog to digital converter.
  • the electrical signal of the photodiode is amplified directly Output to the A / D converter will cause a large part of unwanted signals in the output value of the A / D converter, thereby reducing the conversion accuracy of the A / D converter.
  • FIG. 1 is a schematic diagram of a circuit structure of a conventional fingerprint detection device
  • FIG. 2 is a waveform diagram of a signal received by a constant-scale digital converter.
  • the fingerprint detection device includes a plurality of induction circuits 10 for receiving an optical signal and outputting an inductive electrical signal based on the received optical signal.
  • scanning signals are provided line by line to each of the scanning lines G1 to Gn, so that the induction circuit 10 outputs the induced electrical signals line by line.
  • Each of the signal read lines RL1 to RLm is correspondingly connected to an output terminal of each column of the sensing circuit 10.
  • the induced electrical signal output by the induction circuit 10 is amplified by the amplifier 22 and input to the analog-to-digital converter 21 for analog-to-digital conversion. Because the valleys and ridges in the fingerprint reflect different amounts of light, the magnitudes of the induced electrical signals output by the sensing circuits 10 corresponding to the valleys and ridges are also different.
  • the calculation circuit 30 judges the difference of the induced electrical signals output by each of the inductive circuits 10 according to the output of each of the analog-to-digital converters 21, thereby acquiring the valley and ridge characteristics, and further obtaining a fingerprint image.
  • the magnitude of the induced electrical signal generated by the light reflected by the valley of the fingerprint is shown in the valley of FIG. 2
  • the magnitude of the induced electrical signal generated by the light reflected by the ridge of the fingerprint is shown by the peak of FIG.
  • Com_V there is a common mode component between the induced electrical signal generated according to the valley and the ridge of the fingerprint, that is, Com_V in FIG. 2.
  • the difference between the peak and trough of the signal in FIG. 2 is used, that is, the difference between the induced electrical signals output by different induction circuits 10 is not used.
  • the above-mentioned common mode component Com_V occupies the dynamic range of the analog-to-digital converter 21, and when it is occupied too much, the conversion accuracy of the analog-to-digital converter 21 will be reduced, thereby reducing the accuracy of fingerprint recognition.
  • FIG. 3 is a schematic circuit diagram of a fingerprint detection device according to an embodiment of the present disclosure.
  • the fingerprint detection device includes a detection substrate, a signal converter 20 and a control circuit 40.
  • the detection substrate includes a plurality of pixels, and the plurality of pixels are arranged in multiple rows and columns.
  • An induction circuit 10 is provided in each pixel, and the induction circuit 10 is configured to receive an optical signal and output an inductive electrical signal having a size corresponding to light information of the optical signal.
  • the light information of the optical signal includes, but is not limited to, light intensity.
  • the signal converter 20 includes a plurality of analog-to-digital converters 21, and each of the analog-to-digital converters 21 corresponds to a row of induction circuits 10.
  • the analog-to-digital converter 21 is configured to perform analog-to-digital conversion on a difference between an input signal received at the signal input terminal In and a reference signal received at the reference terminal Ref.
  • the control circuit 40 is connected to the induction circuit 10 and the analog-to-digital converter 21, and is configured to obtain a common mode component of the induced electrical signal output by the induction circuit 10 of at least a part of the plurality of pixels, and provide information about the common mode component. To the plurality of analog-to-digital converters 21.
  • the analog-to-digital converter 21 includes a signal input terminal In and a reference terminal Ref; the control circuit 40 is configured to provide information about a common-mode component to the signal input terminal In and the reference terminal Ref of the analog-to-digital converter 21 One of the two makes the difference between the signal received at the signal input terminal In of the analog-to-digital converter 21 and the reference terminal Ref equal to the difference between the induced electrical signal output by the corresponding induction circuit 10 and the common mode signal.
  • a common mode component of an induced electrical signal output by at least two induction circuits 10 including the induction circuit 10 is acquired, And providing an input signal to the signal input terminal In of the analog-to-digital converter 21 corresponding to the induction circuit 10 and / or a reference signal Ref to the reference terminal Ref of the analog-to-digital converter 21 corresponding to the induction circuit 10 according to the obtained common mode component,
  • the difference between the signal received at the signal input terminal In and the reference terminal Ref of the analog-to-digital converter 21 is equal to the difference between the induced electrical signal output by the corresponding induction circuit 10 and the common mode component.
  • the detection stages corresponding to different induction circuits 10 located in the same column do not overlap with each other, so as to ensure that the analog-to-digital converter 21 performs analog-to-digital conversion on signals at the output of one induction circuit 10 at most at a time.
  • the detection stage corresponding to the induction circuit 10 refers to a stage in which the induction circuit 10 outputs an induced electrical signal according to the received optical signal.
  • the detection stage is not necessarily a continuous time period in time, and may include Discontinuous periods in time.
  • each fingerprint detection cycle may include two fingerprint detection sub-cycles: a first fingerprint detection sub-cycle and a second fingerprint detection sub-cycle.
  • the sensing circuit 10 may be driven line by line, so that the sensing circuit 10 outputs the induced electrical signals line by line, until one driving of all the sensing circuits 10 is completed. In this case, the line-by-line driving of all the sensing circuits 10 can be completed twice in each fingerprint detection cycle.
  • each inductive circuit 10 may include two time periods (detection sub-phases) during which the inductive circuit 10 outputs an induced electrical signal in two fingerprint detection sub-cycles, respectively.
  • the common mode component obtained by the control circuit 40 may be a common mode component of an induced electrical signal output by the at least two sensing circuits 10 in the first fingerprint detection sub-period. It can be understood that, in the case of the n-row induction circuit, each fingerprint detection sub-period may include n detection sub-stages respectively corresponding to the n-row induction circuit.
  • the common mode component of the inductive electrical signals output by the at least two inductive circuits 10 refers to: the inductive electrical signals output by the at least two inductive circuits 10 each include signals of equal magnitude and the same phase. For example, if the three inductive circuits output 5V, 7V, and 10V inductive electrical signals, the common mode component of the three inductive electrical signals is 5V.
  • control circuit 40 may calculate the induction electrical signals output by the induction circuit 10 and the induction electrical outputs of at least two induction circuits 10 including the induction circuit 10.
  • the difference between the common mode components of the signals provides the signal corresponding to the difference to the signal input terminal of the analog-to-digital converter 21.
  • the reference terminal of the analog-to-digital converter 21 can be grounded.
  • the control circuit 40 in the detection phase corresponding to any induction circuit 10, provides the induction electrical signal output by the induction circuit 10 to the signal input terminal In of the corresponding analog-to-digital converter 21, and will include the induction circuit A common mode component of the induced electrical signals output by at least two induction circuits 10 including 10 is provided to a reference terminal Ref of the induction circuit 10.
  • the present disclosure does not limit the manner in which the information related to the common-mode component is provided to the analog-to-digital converter 21, as long as the difference between the signal input terminal and the reference terminal of the analog-to-digital converter 21 is equal to the inductance output by the induction circuit 10 The difference between the electrical signal and the common-mode component is sufficient.
  • the fingerprint recognition process uses the difference of the induced electrical signal output by the induction circuit 10, and does not use the common mode component, and the excessive common mode component affects the conversion accuracy of the analog-to-digital converter 21.
  • the difference between the signal received at the signal input terminal In and the reference terminal Ref of the analog-to-digital converter 21 connected to the inductive circuit 10 is the inductive current output by the inductive circuit 10 during the detection stage of any of the inductive circuits 10.
  • the difference between the signal and the common mode component therefore, at least a part of the common mode component of the inductive electrical signal output by the inductive circuit 10 is eliminated, thereby reducing the occupation of the dynamic range of the analog to digital converter 21 by the common mode component, thereby improving the analog to digital conversion.
  • the conversion accuracy of the device 21 improves the accuracy of fingerprint recognition.
  • the inductive electrical signals generated by the two induction circuits 10 according to the received optical signals are voltage signals of 10V and 20V, respectively
  • the constant-scale digital converter 21 needs to perform analog-to-digital conversion on the analog signals of 10V and 20V, respectively.
  • the common mode component of the two induction circuits 10 is 10V
  • FIG. 4 is a schematic diagram illustrating connections among an induction circuit, a control circuit, and a signal converter in a fingerprint detection device according to an embodiment of the present disclosure.
  • a plurality of signal reading lines RL1 to RLm are provided on the detection substrate, and each signal reading line is connected to an output end of a column of induction circuits 10.
  • the signal converter 20 also includes a plurality of amplifiers 22 connected to the analog-to-digital converters 21 one-to-one.
  • the output of the amplifier 22 is connected to the signal input terminal In of the analog-to-digital converter 21, and the input of the amplifier 21 is connected to a corresponding column.
  • the output terminals (ie, corresponding signal read lines) of the induction circuits 10 are connected, so that the signal input terminal In of each analog-to-digital converter 21 is connected to the output terminal of each induction circuit 10 in the corresponding column.
  • the sensing circuit is an active pixel circuit (APS). As shown in FIG. 4, the sensing circuit includes a photodiode PIN, a reset transistor T1, a follower transistor T2, and a gate transistor T3.
  • the anode of the photodiode PIN is connected to the low-level signal terminal VSS; the cathode is connected to the second electrode of the reset transistor T1, and the low-level signal terminal VSS may be a ground terminal.
  • the control electrode of the reset transistor T1 is connected to the reset terminal Reset of the sensing circuit 10, and the first electrode is connected to the high-level signal terminal Vdd.
  • the control electrode of the follower transistor T2 is connected to the cathode of the photodiode PIN, and the first electrode is connected to the high-level signal terminal Vdd.
  • the control electrode of the gate transistor T3 is connected to the scan terminal Scan of the induction circuit 10, the first electrode of the gate transistor T3 is connected to the second electrode of the follower transistor T2, and the second electrode of the gate transistor T3 is connected to the output terminal of the induction circuit 10. Connected.
  • the scanning end Scan of the sensing circuit 10 is connected to the corresponding scanning line.
  • the fingerprint detection device further includes a current source Is, and an output terminal of each sensing circuit 10 is further connected to the current source Is.
  • the fingerprint detection device may further include a driving circuit (not shown), which is configured to provide a driving signal to the sensing circuit 10 so that the sensing circuit 10 outputs a corresponding induced electrical signal according to the received optical signal.
  • the driving circuit controls the reset transistor T1 to be turned on to reset the photodiode PIN. After that, the reset transistor T1 is controlled to turn off, and the photodiode PIN is illuminated by light to perform photocurrent integration.
  • the gate transistor T3 is controlled to be turned on, and the current source acts on the follower transistor T2, so that the voltage change of the photodiode PIN cathode is transmitted to the input terminal of the amplifier 22 through the follower transistor T2, so that the signal is amplified by the amplifier 22 and output to the analog-to-digital
  • the converter 21 performs analog-to-digital conversion.
  • the fingerprint detection cycle includes a first fingerprint detection sub-cycle and a second fingerprint detection sub-cycle.
  • the detection phase of each sensing circuit 10 includes a first detector located in the first fingerprint detection sub-cycle and the second fingerprint detection sub-cycle, respectively. Phase and second detection sub-phase.
  • the second fingerprint detection sub-period is after the first fingerprint detection sub-period. In the same fingerprint detection cycle, any one of the first detection sub-stages precedes all of the second detection sub-stages.
  • the driving circuit can drive the sensing circuit 10 line by line, and the driving of all the sensing circuits 10 is completed once in each fingerprint detection sub-cycle. In this case, the first detection sub-phases of the induction circuits 10 in the same row overlap, and the second detection sub-phases of the induction circuits 10 in the same row also overlap.
  • control circuit 40 may include a comparison sub-circuit 41, a plurality of switch sub-circuits 42, and a first control sub-circuit 43. Only one induction circuit 10 and its corresponding switch sub-circuit 42 are shown in FIG. 4.
  • the comparison sub-circuit 41 is configured to acquire the induction electric signals output by all the induction circuits 10 in the first fingerprint detection sub-period, and output the smallest one of the acquired induction electric signals as the reference signal.
  • the plurality of switching sub-circuits 42 correspond to the plurality of analog-to-digital converters one-to-one.
  • the first input terminal of the switch sub-circuit 42 is connected to the output terminal of the comparison sub-circuit 41; the second input terminal of the switch sub-circuit 42 is grounded; the output terminal of the switch sub-circuit 42 is connected to the reference terminal Ref of the corresponding analog-to-digital converter 21 .
  • the first control sub-circuit 43 is used to control the first input terminal and the output terminal of each switch sub-circuit 42 to be turned on during the second fingerprint detection sub-period, and to control each switch sub-circuit 42 during the first fingerprint detection sub-period.
  • the second input terminal is conductive with the output terminal.
  • the first control sub-circuit 43 is configured to control the first input terminal and the output terminal of the switch sub-circuit 42 to be conductive during the second detection sub-phase of each induction circuit 10.
  • the second input terminal and the output terminal of the control switch sub-circuit 42 are turned on, so that in each first detection sub-phase, the reference terminals Ref of all the analog-to-digital converters 21 are grounded, and in each In the second detection sub-phase, the reference terminals Ref of all the analog-to-digital converters 21 receive a reference signal (that is, the smallest one of the induced electrical signals output by the induction circuits 10 in the first detection sub-period).
  • the difference between the signal input terminal In and the reference terminal Ref of the analog-to-digital converter 21 is: the corresponding sensing circuit 10 is in the second detection sub-phase.
  • the smallest one of all inductive electrical signals is the common mode component of all inductive electrical signals, the common mode component between the inductive electrical signals output by all inductive circuits 10 to the dynamic range of the analog-to-digital converter 21 is also eliminated.
  • the occupancy improves the conversion accuracy of the analog-to-digital converter 21.
  • the fingerprint detection device may be a display device, and each pixel may also perform display.
  • the comparison sub-circuit 41 may only obtain the induction electric signals output by each induction circuit 10 in the area covered by the fingerprint in the first fingerprint detection sub-period, and use the smallest one of the acquired induction electric signals as the Reference signal.
  • the pixel with the smallest brightness can be obtained by detecting the brightness, and the induced electrical signal output by the sensing circuit 10 in the obtained pixel is the reference signal.
  • each sensing circuit 10 can receive the same or similar optical signals in two fingerprint detection sub-periods in each fingerprint detection cycle.
  • the fingerprint detection device further includes a calculation circuit 30, which is connected to each analog-to-digital converter 21 and is configured to determine according to an output signal of each analog-to-digital converter 21 in each fingerprint detection cycle.
  • the difference between the induced electrical signals output by any two adjacent induction circuits 10, and the difference between the optical signals received by any two adjacent induction circuits is determined according to the difference between the induced electrical signals output by any two adjacent induction circuits 10, so that Determine the fingerprint image.
  • FIG. 5 is a schematic diagram illustrating connections between an induction circuit, a control circuit, and a signal converter in a fingerprint detection device according to an embodiment of the present disclosure.
  • the structure of the induction circuit 10 and the connection relationship with the signal read line RL are the same as those in the embodiment described with reference to FIG. 4, and are not repeated here.
  • the fingerprint detection period includes a first fingerprint detection sub-period and a second fingerprint detection sub-period.
  • the detection phase of each inductive circuit 10 includes a first detection sub-phase located in the first fingerprint detection sub-cycle and The second detection sub-phase is located in the second fingerprint detection sub-cycle.
  • the start time of the second fingerprint detection sub-cycle is after the start time of the first fingerprint detection sub-cycle.
  • the fingerprint detection device may also include a driving circuit. Unlike the above embodiment, the driving circuit in this embodiment may drive the sensing circuit 10 line by line only in the first fingerprint detection sub-period.
  • a signal input terminal In of each analog-to-digital converter 21 is connected to an output terminal of each inductive circuit 10 in a corresponding column through an amplifier 22; different from the foregoing embodiment, the The reference terminal Ref is always grounded.
  • the configuration of the control circuit 40 is also different from that in the above-described embodiment.
  • the control circuit 40 includes a plurality of capacitors C, a plurality of switching transistors T4, and a second control sub-circuit 44.
  • a plurality of capacitors C are connected in series in a predetermined order, and two ends of each capacitor C are connected to the output terminals of two adjacent induction circuits 10 respectively, so that the output terminals of the plurality of induction circuits 10 are connected in sequence through the capacitors. Only two induction circuits 10 and the capacitance C between them are shown schematically in FIG. 5.
  • a plurality of capacitors C are connected in a serpentine manner, that is, a capacitor C is connected between every two adjacent induction circuits 10 in the first row, and the last induction circuit 10 in the first row and the last in the second row are connected.
  • a capacitor C is connected between one induction circuit 10, a capacitor is connected between the first induction circuit 10 in the second row and the first induction circuit 10 in the third row, and so on.
  • the switching transistor T4 corresponds to the induction circuit on a one-to-one basis.
  • the control electrode of each switching transistor T4 is connected to the second control sub-circuit 44, the first electrode is connected to the output terminal of the corresponding induction circuit 10, and the second electrode is grounded.
  • the second control sub-circuit 44 is used to provide a turn-off signal to the control electrode of the corresponding switching transistor T4 in the first detection sub-phase of each induction circuit 10; and in the second detection sub-phase of each induction circuit 10, The gate of the corresponding switching transistor T4 provides an on signal.
  • the calculation circuit 30 is connected to each analog-to-digital converter 21, and is used to determine the difference between the induced electrical signals output by any two adjacent induction circuits 10 according to the output signal of each analog-to-digital converter 21 in each fingerprint detection cycle, and The fingerprint image is determined according to the difference between the induced electrical signals output by any two adjacent induction circuits 10.
  • the fingerprint detection cycle includes a first fingerprint detection sub-cycle and a second fingerprint detection sub-cycle, and the first detection sub-phase and the second detection sub-phase of each sensing circuit 10 are located in the first fingerprint detection sub-cycle and the second fingerprint detection sub-cycle, respectively.
  • the two sensing circuits 10 output corresponding inductive electrical signals according to the received optical signals.
  • the inductive electrical signals output by the left inductive circuit 10 are denoted as X, and the inductive signals on the right are inducted.
  • the induced electrical signal output by the circuit 10 is recorded as Y, so that the voltage across the capacitor C between the two induction circuits 10 is the difference between X and Y; thereafter, the second of the left induction circuit 10 in the second fingerprint detection sub-period is In the detection sub-phase, the left switching transistor T4 is turned on, so that the output terminal of the left induction circuit 10 (that is, one end of the capacitor C) is grounded.
  • the input signal received by the signal input terminal of the right analog-to-digital converter 21 is the difference between the induced electrical signals output by the two inductive circuits 10, so that the right analog-to-digital converter 2 1 Analog-to-digital conversion of the difference between the two induced electrical signals.
  • the calculation circuit 30 can obtain the difference between the induced electrical signals output by each two adjacent induction circuits 10, so as to obtain the signals received by each two adjacent induction circuits 10.
  • the difference in light signals can be used to obtain a spatial distribution map of light intensity to further obtain fingerprint information.
  • the edge position of the detection substrate there may be cases where the difference between the induction circuits 10 cannot be accurately detected, for example, the output end of the last induction circuit 10 in the first row and the last induction circuit 10 in the second row Capacitors are connected between the output terminals of the two, and the output terminals of the two induction circuits 10 are connected to the same signal reading line RLm. Therefore, when the calculation circuit calculates, it will consider the optical signals received by the two induction circuits 10 Are the same. For this reason, when the computing circuit obtains the fingerprint information, the corresponding fingerprint information at the first and last columns of the sensing circuit 10 may no longer be calculated.
  • a fingerprint detection method for use in a fingerprint detection device.
  • the fingerprint detection device includes a detection substrate and a signal converter 20.
  • the detection substrate includes a plurality of lines and Multiple columns and multiple pixels, as shown in FIG. 3, each pixel is provided with an induction circuit 10 for receiving a light signal and outputting a corresponding induced electrical signal based on the received light signal;
  • the signal converter 20 includes a plurality of Analog-to-digital converters 21, each of which corresponds to a row of induction circuits 10.
  • the fingerprint detection method includes: obtaining, through the control circuit 40, a common mode component of an induced electrical signal output by an induction circuit of at least a part of the plurality of pixels, and providing information about the common mode component to the plurality of pixels.
  • a common mode component of the induced electrical signals output by at least two induction circuits including the induction circuit 10 is acquired, and the corresponding mode of the induction circuit 10 is obtained according to the obtained common mode component.
  • a signal input terminal In of the digital-to-digital converter 21 provides an input signal and / or a reference signal to a reference terminal of the analog-to-digital converter 21 corresponding to the induction circuit 10, so that the signal input terminal In and the reference terminal Ref of the analog-to-digital converter 21
  • the difference between the received signals is equal to the difference between the induced electrical signal output by the corresponding induction circuit 10 and the common mode component. This process can be performed by the control circuit 40 described above.
  • the analog-to-digital converter 21 performs analog-to-digital conversion on the difference between the input signal received at the signal input terminal In and the reference signal received at the reference terminal Ref.
  • the detection stages corresponding to different sensing circuits 10 in the same column do not overlap with each other.
  • the difference between the signal received at the signal input terminal In and the reference terminal Ref of the analog-to-digital converter 21 corresponding to the induction circuit 10 is the induction signal output from the induction circuit 10 and the common
  • the difference between the analog components is therefore equivalent to eliminating at least part of the common mode components of the inductive electrical signal output by the inductive circuit 10, thereby reducing the occupation of the dynamic range of the analog-to-digital converter 21 by the common-mode components, thereby improving the analog-to-digital conversion
  • the conversion accuracy of the device 21 can improve the accuracy of fingerprint recognition without using a high-digit analog-to-digital converter.
  • each analog-to-digital converter 21 is connected to the output terminal of each induction circuit 10 in the corresponding column.
  • the fingerprint detection cycle includes a first fingerprint detection sub-period and a second fingerprint detection sub-period.
  • the detection phase of each inductive circuit 10 includes a first detection sub-phase and a first detection sub-phase respectively located in the first fingerprint detection sub-cycle and the second fingerprint detection sub-cycle.
  • the second fingerprint detection sub-period is after the first fingerprint detection sub-period. In the same fingerprint detection cycle, any one of the first detection sub-stages precedes all of the second detection sub-stages.
  • the control circuit 40 may include a comparison sub-circuit 41, a plurality of switching sub-circuits 42, and a first control sub-circuit 43.
  • Acquiring a common mode component of an induced electrical signal output by an induction circuit of at least a part of the plurality of pixels through the control circuit 40, and providing information about the common mode component to the plurality of analog-to-digital converters 21 includes: In the first fingerprint detection sub-period, the inductive electrical signal output by at least part of the inductive circuit is obtained through the comparison sub-circuit 41, and the smallest one of the acquired inductive electrical signals is provided as a reference signal to the switch sub-circuit 42; and in the second fingerprint, In the detection sub-period, the first control sub-circuit 43 is used to control the switch sub-circuit 42 to provide the reference signal to the reference terminal of the corresponding analog-to-digital converter 21. In the first fingerprint detection sub-period, the first control sub-circuit 43 controls the switch sub-circuit 42 to provide the
  • the signal input terminal In of the corresponding analog-to-digital converter 21 provides an input signal and / or provides a reference signal to the reference terminal Ref of the analog-to-digital converter 21 corresponding to the sensing circuit 10.
  • the difference between the induced electrical signals output by any two adjacent induction circuits 10 is determined according to the output signals of the analog-to-digital converters 21, and the arbitrary adjacent is determined according to the difference between the two electrical signals output by any two adjacent induction circuits 10.
  • the difference between the light signals received by the two sensing circuits 10 determines a fingerprint image.
  • the inductive circuit 10 can output the inductive electric signal line by line under the driving of the driving circuit.
  • the driving process and the principle of fingerprint detection have been described above, and are not repeated here.
  • a signal input terminal of each analog-to-digital converter 21 is connected to an output terminal of each inductive circuit 10 in a corresponding column, and a reference terminal of each analog-to-digital converter 21 is grounded.
  • the control circuit includes: a plurality of capacitors C connected in series in a predetermined order, and two ends of each capacitor C are respectively connected to the output ends of two adjacent induction circuits 10; and a plurality of induction circuits 10 One-to-one corresponding plurality of switching transistors T4, the first pole of each switching transistor is connected to the output terminal of the corresponding induction circuit 10, and the second pole is grounded; and the second controller is connected to the control electrode of each switching transistor T4. Circuit 40.
  • the fingerprint detection cycle includes a first fingerprint detection sub-cycle and a second fingerprint detection sub-cycle; the detection phase of each sensing circuit 10 includes a first detection sub-phase located in the first fingerprint detection sub-cycle and a second fingerprint detection sub-cycle. In the same detection phase, the first detection sub-phase is located before the second detection sub-phase; the second detection sub-phases of different induction circuits 10 do not overlap each other.
  • the signal input terminal In of the analog-to-digital converter 21 provides an input signal and / or provides a reference signal to the reference terminal Ref of the analog-to-digital converter 21 corresponding to the inductive circuit 10 ”includes:
  • the difference between the induced electrical signals output by any two adjacent induction circuits 10 is determined according to the output signals of the analog-to-digital converters 21, and the arbitrary adjacent is determined according to the difference between the two electrical signals output by any two adjacent induction circuits 10.
  • the difference between the light signals received by the two sensing circuits 10 determines a fingerprint image.
  • the inductive circuit 10 can output the inductive electric signal line by line under the driving of the driving circuit.
  • the driving process and the principle of fingerprint detection have been described above, and are not repeated here.
  • control circuit in the present disclosure may be implemented by means of hardware and / or software.
  • control circuit may be implemented as a processor and a memory storing a program.
  • processor executes a program stored in the memory, each component in the control circuit (for example, a comparison sub-circuit, a switch sub-circuit, a first control sub-circuit, and a first Two control sub-circuits, etc.).

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Abstract

本公开提供一种指纹检测装置和指纹检测方法。指纹检测装置包括检测基板和信号转换器。检测基板包括排列成多行和多列的多个像素。每个像素中包括感应电路，所述感应电路构造为接收光信号并基于接收的光信号输出感应电信号。信号转换器包括多个模数转换器，每个模数转换器连接一列感应电路。指纹检测装置还包括控制电路，其与感应电路和模数转换器相连，并且构造为：获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器。模数转换器构造为对来自相应感应电路的感应电信号与所述共模信号之差进行模数转换。

Description

指纹检测装置和指纹检测方法
相关申请的交叉引用
本申请要求于2018年5月31日提交的中国专利申请No.201810550911.X的优先权，其内容通过引用方式整体并入本文。
技术领域
本公开涉及指纹检测领域，具体涉及一种指纹检测装置和指纹检测方法。
背景技术
在指纹检测装置中，每个像素中均设置有光敏二极管。在进行指纹扫描时，由于指纹谷脊之间的差异，使得照射到指纹上的光线发生不同的反射，从而使得光敏二极管处感测的光强不同。通过依次读出各个光敏二极管的电流，即可实现对指纹谷脊的检测。
发明内容
一方面，本公开提供一种指纹检测装置，包括检测基板和信号转换器，所述检测基板包括排列成多行和多列的多个像素，每个像素中包括感应电路，所述感应电路构造为接收光信号并基于接收的光信号输出感应电信号；所述信号转换器包括多个模数转换器，每个模数转换器连接一列感应电路，
其中，所述指纹检测装置还包括控制电路，所述控制电路与所述感应电路和所述模数转换器相连，并且构造为：获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器，并且
所述模数转换器构造为对来自相应感应电路的感应电信号与所述共模信号之差进行模数转换。
在一些实施例中，所述模数转换器包括信号输入端和参考端，所述控制电路构造为将关于所述共模分量的信息提供至所述模数转换器的信号输入端和参考端中的一者，使得所述模数转换器的信号输入端与参考端接收到的信号之差等于相应感应电路的感应电信号与所述共模信号之差。
在一些实施例中，每个模数转换器的信号输入端与相应列中各感应电路的输出端相连，所述控制电路包括：比较子电路，构造为在第一指纹检测子周期中，获取至少部分感应电路输出的感应电信号，并将获取的感应电信号中的最小一个作为参考信号进行输出；与所述多个模数转换器一一对应的多个开关子电路，所述开关子电路的第一输入端与所述比较子电路的输出端相连，所述开关子电路的输出端与相应的模数转换器的参考端相连；以及第一控制子电路，构造为在第二指纹检测子周期中，控制每个开关子电路的第一输入端与输出端导通以输出所述参考信号，其中，所述第二指纹检测子周期在所述第一指纹检测子周期之后。
在一些实施例中，所述开关子电路的第二输入端接地，所述第一控制子电路还构造为在第一指纹检测子周期中控制每个开关子电路的第二输入端与输出端导通。
在一些实施例中，每个模数转换器的信号输入端与相应列中各感应电路的输出端相连，每个模数转换器的参考端接地；所述控制电路包括：依次串联的多个电容，每个电容的两端分别与相邻两个感应电路的输出端相连；与多个感应电路一一对应的多个开关晶体管，所述开关晶体管的第一极与相应的感应电路的输出端相连，所述开关晶体管的第二极接地；以及与每个开关晶体管的控制极相连的第二控制子电路，所述第二控制子电路构造为：在第一指纹检测子周期，为开关晶体管的控制极提供关断信号；并在第二指纹检测子周期，为开关晶体管的控制极提供开启信号，所述第二指纹检测子周期的起始时间在所述第一指纹检测子周期的起始时间之后。
在一些实施例中，所述指纹检测装置还包括计算电路，所述计算电路与各模数转换器相连，并且构造为根据各模数转换器的输出信 号判断任意相邻两个感应电路输出的感应电信号之差，并根据任意相邻两个感应电路输出的感应电信号之差确定指纹图像。
在一些实施例中，所述感应电路包括：光敏二极管，其阳极与低电平信号端相连；第一晶体管，其控制极与所述感应电路的重置端相连，第一极与高电平信号端相连，第二极与所述光敏二极管的阴极相连；第二晶体管，其控制极与所述光敏二极管的阴极相连，第一极与所述高电平信号端相连；第三晶体管，其控制极与所述感应电路的扫描端相连，第一极与所述第二晶体管的第二极相连，第二极与所述感应电路的输出端相连；每个感应电路的输出端与电流源相连。
在一些实施例中，所述信号转换器还包括与多个模数转换器一一对应连接的多个放大器，所述放大器的输出端与相应的模数转换器的信号输入端相连，所述放大器的输入端与相应列的感应电路的输出端相连。
在一些实施例中，所述比较子电路仅获取所述检测基板上指纹所覆盖范围中的感应电路输出的感应电信号，并将所获取的感应电信号中的最小一个作为所述参考信号输出。
在一些实施例中，所述比较子电路通过检测各子像素的亮度来获取亮度最小的像素，并将获取的像素中的感应电路输出的感应电信号作为所述参考信号输出。
另一方面，本公开还提供一种指纹检测方法，用于指纹检测装置中，所述指纹检测装置包括检测基板和信号转换器，所述检测基板包括排列成多行和多列的多个像素，每个像素中包括感应电路，所述感应电路构造为接收光信号并基于所接收的光信号输出感应电信号；所述信号转换器包括多个模数转换器，每个模数转换器连接一列所述感应电路，
其中，所述指纹检测方法包括：
通过控制电路获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器，并且
通过所述模数转换器对来自相应感应电路的感应电信号与所述 共模信号之差进行模数转换。
在一些实施例中，所述模数转换器包括信号输入端和参考端，将关于所述共模分量的信息提供至所述多个模数转换器包括：将关于所述共模分量的信息提供至所述模数转换器的信号输入端和参考端中的一者，使得所述模数转换器的信号输入端与参考端接收到的信号之差等于相应感应电路的感应电信号与所述共模信号之差。
在一些实施例中，每个模数转换器的信号输入端与相应列中各感应电路的输出端相连，所述控制电路包括比较子电路、开关子电路和第一控制子电路，
通过控制电路获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器包括：
第一指纹检测子周期中，通过比较子电路获取至少部分感应电路输出的感应电信号，并将获取的感应电信号中的最小一个作为参考信号提供至开关子电路；以及
在第二指纹检测子周期中，通过所述第一控制子电路控制所述开关子电路将所述参考信号提供至相应的模数转换器的参考端，所述第二指纹检测子周期在所述第一指纹检测子周期之后。
在一些实施例中，在第一指纹检测子周期中，所述第一控制子电路控制开关子电路将接地信号提供至相应的模数转换器的参考端。
在一些实施例中，每个模数转换器的信号输入端与相应列中各感应电路的输出端相连，每个模数转换器的参考端接地；
所述控制电路包括：依次串联的多个电容，每个电容的两端分别与相邻两个感应电路的输出端相连；与多个感应电路一一对应的多个开关晶体管，所述开关晶体管的第一极与相应的感应电路的输出端相连，所述开关晶体管的第二极接地；与每个开关晶体管的控制极相连的第二控制子电路，
通过控制电路获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器包括：在第一指纹检测子周期，通过第二控制子电 路为开关晶体管的控制极提供关断信号；并在第二指纹检测子周期，通过第二控制子电路为开关晶体管的控制极提供开启信号，所述第二指纹检测子周期的起始时间在所述第一指纹检测子周期的起始时间之后。
在一些实施例中，所述指纹检测装置还包括计算电路，所述指纹检测方法还包括：
通过所述计算电路根据各模数转换器的输出信号判断任意相邻两个感应电路输出的感应电信号之差，并根据任意相邻两个感应电路输出的感应电信号之差确定指纹图像。
在一些实施例中，所述比较子电路仅获取所述检测基板上指纹所覆盖范围中的感应电路输出的感应电信号，并将所获取的感应电信号中的最小一个作为所述参考信号输出。
在一些实施例中，所述比较子电路通过检测各子像素的亮度来获取亮度最小的像素，并将获取的像素中的感应电路输出的感应电信号作为所述参考信号输出。
附图说明
附图是用来提供对本公开的进一步理解，并且构成说明书的一部分，与下面的具体实施方式一起用于解释本公开，但并不构成对本公开的限制。在附图中：
图1是传统指纹检测装置的电路结构示意图；
图2是传统模数转换器接收到的信号的波形示意图；
图3是根据本公开实施例的指纹检测装置的电路示意图；
图4是示出根据本公开实施例的指纹检测装置中的感应电路、控制电路和信号转换器之间的连接的示意图；
图5是示出根据本公开实施例的指纹检测装置中的感应电路、控制电路和信号转换器之间的连接的示意图。
具体实施方式
以下结合附图对本公开的具体实施方式进行详细说明。应当理 解的是，此处所描述的具体实施方式仅用于说明和解释本公开，并不用于限制本公开。
在指纹检测装置中根据光敏二极管产生的电信号来判断指纹信息时，需要先对电信号进行模数转换。通常，在对电信号进行模数转换时采用的方式是将电信号放大后直接输出至模数转换器的输入端。但是，由于从指纹的谷脊反射的光均会使光敏二极管产生电信号，而与指纹检测有关的只是与谷脊对应的电信号之间的差异，因此，将光敏二极管的电信号放大后直接输出至模数转换器，会造成模数转换器的输出值中有一大部分无用信号，从而降低了模数转换器的转换精度。
图1是常规指纹检测装置的电路结构示意图，图2是常规模数转换器接收到的信号的波形示意图。如图1所示，指纹检测装置包括多个感应电路10，用于接收光信号并基于接收的光信号输出感应电信号。在进行指纹检测时，向各扫描线G1～Gn逐行提供扫描信号，从而使得感应电路10逐行输出感应电信号。各信号读取线RL1～RLm与各列感应电路10的输出端对应相连。感应电路10输出的感应电信号经过放大器22的放大后输入至模数转换器21进行模数转换。由于指纹中谷和脊对光线的反射量不同，因此，谷和脊所对应的感应电路10输出的感应电信号的大小也不同。计算电路30根据各模数转换器21的输出，判断各感应电路10输出的感应电信号的差异，从而获取谷和脊特征，进而获得指纹图像。
如图2所示，根据指纹的谷所反射的光产生的感应电信号大小如图2中的波谷所示，根据指纹的脊所反射的光产生的感应电信号大小如图2中的波峰所示，根据指纹的谷和脊所反射的光而产生的感应电信号之间存在共模分量，即图2中的Com_V。在根据模数转换器的输出来识别指纹图像时，利用的是图2中信号的波峰和波谷之间的差值，即，不同感应电路10输出的感应电信号的差值，并不会利用上述共模分量Com_V。而且，共模分量会占用模数转换器21的动态范围，当占用过多时，会降低模数转换器21的转换精度，从而降低指纹识别的精度。
为了提高指纹检测装置中模数转换器的转换精度，本公开提供 一种指纹检测装置。图3是根据本公开实施例的指纹检测装置的电路示意图。如图3所示，所述指纹检测装置包括检测基板、信号转换器20和控制电路40。所述检测基板包括多个像素，多个像素排成多行多列。每个像素中设置感应电路10，感应电路10用于接收光信号并输出大小与所述光信号的光线信息相对应的感应电信号，所述光信号的光线信息包括但不限于光线强度。信号转换器20包括多个模数转换器21，每个模数转换器21对应一列感应电路10。模数转换器21用于对其信号输入端In接收到的输入信号与参考端Ref接收到的参考信号之差进行模数转换。
控制电路40与感应电路10和模数转换器21相连，用于获取所述多个像素中的至少一部分的感应电路10输出的感应电信号的共模分量，并将关于共模分量的信息提供至所述多个模数转换器21。在一些实施例中，模数转换器21包括信号输入端In和参考端Ref；控制电路40构造为将关于共模分量的信息提供至模数转换器21的信号输入端In和参考端Ref中的一者，使得模数转换器21的信号输入端In与参考端Ref接收到的信号之差等于相应感应电路10输出的感应电信号与共模信号之差。在一些实施例中，在每个指纹检测周期中的任一感应电路10所对应的检测阶段，获取包括该感应电路10在内的至少两个感应电路10输出的感应电信号的共模分量，并根据获得的共模分量向感应电路10所对应的模数转换器21的信号输入端In提供输入信号和/或向感应电路10所对应的模数转换器21的参考端Ref提供参考信号，以使模数转换器21的信号输入端In与参考端Ref接收到信号之差等于相应感应电路10输出的感应电信号与所述共模分量之差。
可以理解的是，位于同一列的不同感应电路10所对应的检测阶段互不交叠，以保证模数转换器21在每个时刻最多只针对一个感应电路10输出端的信号进行模数转换。
需要说明的是，上述感应电路10对应的检测阶段是指：感应电路10根据接收到的光信号输出感应电信号的阶段，所述检测阶段并不一定是时间上连续的时间段，也可以包括在时间上不连续的时间段。 此外，每个指纹检测周期可以包括两个指纹检测子周期：第一指纹检测子周期和第二指纹检测子周期。在每个指纹检测子周期，可以对感应电路10进行逐行驱动，以使感应电路10逐行输出感应电信号，直至完成对所有感应电路10的一次驱动。这种情况下，在每个指纹检测周期中，可以完成两次对所有感应电路10的逐行驱动。相应地，每个感应电路10的检测阶段可以包括该感应电路10分别在两个指纹检测子周期中输出感应电信号的两个时间段(检测子阶段)。在一些实施例中，控制电路40所获得的共模分量可以为至少两个感应电路10在第一指纹检测子周期中输出的感应电信号的共模分量。可以理解的是，在n行感应电路的情况下，每个指纹检测子周期可以包括分别对应于n行感应电路的n个检测子阶段。
还需要说明的是，至少两个感应电路10输出的感应电信号的共模分量是指：至少两个感应电路10输出的感应电信号中均包含的大小相等、相位相同的信号量。例如，三个感应电路分别输出为5V、7V和10V的感应电信号，则该三个感应电信号的共模分量为5V。
在一些实施例中，在任一感应电路10所对应的检测阶段，控制电路40可以计算该感应电路10输出的感应电信号与包括该感应电路10在内的至少两个感应电路10输出的感应电信号的共模分量的差值，将与差值对应的信号提供至模数转换器21的信号输入端，此时，可以将模数转换器21的参考端接地。在一些实施例中，在任意感应电路10所对应的检测阶段，控制电路40将感应电路10输出的感应电信号提供给相应的模数转换器21的信号输入端In，而将包括该感应电路10在内的至少两个感应电路10输出的感应电信号的共模分量提供给感应电路10的参考端Ref。本公开中对向模数转换器21提供与共模分量有关的信息的方式不做限定，只要使得模数转换器21的信号输入端与参考端接收到信号之差等于该感应电路10输出的感应电信号与共模分量之差即可。
如上所述，指纹识别过程所利用的是感应电路10输出的感应电信号的差值，并不会利用共模分量， 而且共模分量过大会影响模数转换器21的转换精度。在本公开中，由于在任一感应电路10的检测阶 段，该感应电路10所连接的模数转换器21的信号输入端In与参考端Ref接收到的信号之差为感应电路10输出的感应电信号与共模分量之差，因此，消除了至少一部分感应电路10输出的感应电信号的共模分量，从而减少了共模分量对模数转换器21的动态范围的占用，进而提高了模数转换器21的转换精度，提高了指纹识别的精度。例如，当两个感应电路10根据各自接收到的光信号而生成的感应电信号分别为10V和20V的电压信号时，常规模数转换器21需要对10V和20V的模拟信号分别进行模数转换；而在本公开中，两个感应电路10的共模分量为10V，模数转换器21只需对10V-10V＝0V的模拟信号以及20V-10V＝10V的模拟信号进行模数转换即可。
下面结合图3至图5对本公开的指纹检测装置的两种具体实施方式进行介绍。
图4是示出根据本公开实施例的指纹检测装置中的感应电路、控制电路和信号转换器之间的连接的示意图。如图3所示，所述检测基板上设置有多条信号读取线RL1～RLm，每条信号读取线连接一列感应电路10的输出端。信号转换器20还包括与多个模数转换器21一一对应连接的多个放大器22，放大器22的输出端与模数转换器21的信号输入端In相连，放大器21的输入端与相应一列感应电路10的输出端(即，相应的信号读取线)相连，从而使得每个模数转换器21的信号输入端In与相应列中各感应电路10的输出端相连。
在一些实施例中，感应电路为主动式像素电路(APS)。如图4所示，感应电路包括光敏二极管PIN、重置晶体管T1、跟随晶体管T2和选通晶体管T3。光敏二极管PIN的阳极与低电平信号端VSS相连；阴极与重置晶体管T1的第二极相连，低电平信号端VSS可以为接地端。重置晶体管T1的控制极与感应电路10的重置端Reset相连，第一极与高电平信号端Vdd相连。跟随晶体管T2的控制极与光敏二极管PIN的阴极相连，第一极与高电平信号端Vdd相连。选通晶体管T3的控制极与感应电路10的扫描端Scan相连，选通晶体管T3的第一极与跟随晶体管T2的第二极相连，选通晶体管T3的第二极与感应电路10的输出端相连。感应电路10的扫描端Scan与相 应行的扫描线相连。所述指纹检测装置还包括电流源Is，每个感应电路10的输出端还与电流源Is相连。
所述指纹检测装置还可以包括驱动电路(未示出)，所述驱动电路用于为感应电路10提供驱动信号，以使感应电路10根据接收到的光信号输出相应的感应电信号。在进行指纹检测之前，驱动电路控制重置晶体管T1开启，从而对光敏二极管PIN进行重置；之后，控制重置晶体管T1关断，光敏二极管PIN受到光照而进行光电流积分，当积分到一定时间后，控制选通晶体管T3开启，电流源对跟随晶体管T2进行作用，使得光敏二极管PIN阴极的电压变化经过跟随晶体管T2传递到放大器22的输入端，从而经放大器22进行信号放大后输出给模数转换器21进行模数转换。
所述指纹检测周期包括第一指纹检测子周期和第二指纹检测子周期，每个感应电路10的检测阶段包括分别位于第一指纹检测子周期和第二指纹检测子周期中的第一检测子阶段和第二检测子阶段。第二指纹检测子周期在所述第一指纹检测子周期之后。在同一个指纹检测周期中，任意一个第一检测子阶段均先于所有的第二检测子阶段。驱动电路可以逐行对感应电路10进行驱动，且在每个指纹检测子周期内均完成一次对所有感应电路10的驱动。这种情况下，同一行中的感应电路10的第一检测子阶段重合，同一行中的感应电路10的第二检测子阶段也重合。
在一些实施例中，控制电路40可以包括比较子电路41、多个开关子电路42和第一控制子电路43。图4中仅示出了一个感应电路10及其对应的开关子电路42。比较子电路41用于在第一指纹检测子周期中获取所有感应电路10输出的感应电信号，并将获取的感应电信号中的最小一个作为所述参考信号进行输出。多个开关子电路42与多个模数转换器21一一对应。开关子电路42的第一输入端与比较子电路41的输出端相连；开关子电路42的第二输入端接地；开关子电路42的输出端与相应的模数转换器21的参考端Ref相连。第一控制子电路43用于在第二指纹检测子周期中控制每个开关子电路42的第一输入端与输出端导通，以及在第一指纹检测子周期中控制每个开关 子电路42的第二输入端与输出端导通。在一些实施例中，第一控制子电路43用于在每个感应电路10的第二检测子阶段，控制开关子电路42的第一输入端与输出端导通；在每个感应电路10的第一检测子阶段，控制开关子电路42的第二输入端与输出端导通，从而使得在每个第一检测子阶段，所有模数转换器21的参考端Ref均接地，而在每个第二检测子阶段，所有模数转换器21的参考端Ref均接收到参考信号(即，第一个检测子周期中各感应电路10输出的感应电信号中的最小一者)。因此，在第二指纹检测子周期中的任意一个第二检测子阶段，模数转换器21的信号输入端In与参考端Ref之间的差值为：相应感应电路10在第二检测子阶段输出的感应电信号与所有感应电路在第一指纹检测子周期输出的感应电信号中最小一者之间的差值。而由于所有感应电信号中最小一者即为所有感应电信号的共模分量，因此，也就消除了所有感应电路10输出的感应电信号之间的共模分量对模数转换器21动态范围的占用，提高了模数转换器21的转换精度。
在一些实施例中，所述指纹检测装置可以为显示装置，每个像素还可以进行显示。这种情况下，比较子电路41可以只获取指纹所覆盖范围中的各感应电路10在第一指纹检测子周期输出的感应电信号，并将所获取的感应电信号中的最小一个作为所述参考信号。在一些实施例中，可以通过检测亮度方式获取亮度最小的像素，并将获取的像素中感应电路10输出的感应电信号即为参考信号。另外，可以通过驱动电路的驱动，使得每个感应电路10在每个指纹检测周期中的两个指纹检测子周期内接收相同或相近的光信号。
如图3所示，所述指纹检测装置还包括计算电路30，计算电路30与各模数转换器21相连，用于在每个指纹检测周期中，根据各模数转换器21的输出信号判断任意相邻两个感应电路10输出的感应电信号之差，并根据任意相邻两个感应电路10输出的感应电信号之差确定任意相邻两个感应电路接收到的光信号的差异，从而确定指纹图像。
图5是示出根据本公开实施例的指纹检测装置中的感应电路、 控制电路和信号转换器之间的连接的示意图。在该实施例中，感应电路10的结构以及与信号读取线RL之间的连接关系和参照图4描述的实施例中的相同，这里不再赘述。另外，类似于上述实施例，指纹检测周期包括第一指纹检测子周期和第二指纹检测子周期，每个感应电路10的检测阶段包括位于第一指纹检测子周期中的第一检测子阶段和位于第二指纹检测子周期中的第二检测子阶段。第二指纹检测子周期的起始时间在所述第一指纹检测子周期的起始时间之后。当然，也可以不必将每个第一检测子阶段均设置在所有的第二检测子阶段之前，只要保证同一检测阶段中，第一检测子阶段位于第二检测子阶段之前，且位于不同行的感应电路10的第二检测子阶段互不交叠即可。所述指纹检测装置同样可以包括驱动电路，而与上述实施例不同的是，本实施例中的驱动电路可以仅在第一指纹检测子周期中对感应电路10逐行进行驱动。
如图5所示，每个模数转换器21的信号输入端In通过放大器22与相应列中各感应电路10的输出端相连；与上述实施例不同的是，每个模数转换器21的参考端Ref一直是接地的。
另外，控制电路40的结构也与上述实施例中的不同。如图5所示，控制电路40包括多个电容C、多个开关晶体管T4和第二控制子电路44。多个电容C沿预定顺序依次串联，每个电容C的两端分别与相邻两个感应电路10的输出端相连，从而使得多个感应电路10的输出端通过电容顺次相连。图5中仅示意性地示出了两个感应电路10及二者之间的电容C。在一些实施例中，多个电容C采用蛇形串联方式，即，第一行中每相邻两个感应电路10之间连接一个电容C，第一行最后一个感应电路10与第二行最后一个感应电路10之间连接一个电容C，第二行第一个感应电路10与第三行第一个感应电路10之间连接一个电容，以此类推。开关晶体管T4与感应电路一一对应，每个开关晶体管T4的控制极与第二控制子电路44相连，第一极与相应的感应电路10的输出端相连，第二极接地。第二控制子电路44用于在每个感应电路10的第一检测子阶段，向相应的开关晶体管T4的控制极提供关断信号；并在每个感应电路10的第二检测子阶段， 为相应的开关晶体管T4的控制极提供开启信号。计算电路30与各模数转换器21相连，用于在每个指纹检测周期中，根据各模数转换器21的输出信号判断任意相邻两个感应电路10输出的感应电信号之差，并根据任意相邻两个感应电路10输出的感应电信号之差确定指纹图像。
以指纹检测周期包括第一指纹检测子周期和第二指纹检测子周期、每个感应电路10的第一检测子阶段和第二检测子阶段分别位于第一指纹检测子周期和第二指纹检测子周期中为例，首先，在第一指纹检测子周期，两个感应电路10均根据各自接收到的光信号输出相应的感应电信号，左边感应电路10输出的感应电信号记为X，右边感应电路10输出的感应电信号记为Y，从而使得两个感应电路10之间的电容C两端的电压为X、Y之差；之后，在第二指纹检测子周期中左边感应电路10的第二检测子阶段，将左边的开关晶体管T4开启，从而使得左边感应电路10的输出端(即，电容C的一端)接地，由于电容C的自举作用，电容C另一端的电压相应降低至Y-X，从而使右边模数转换器21的信号输入端接收到的输入信号为两个感应电路10输出的感应电信号之差，进而使得右边模数转换器21对两个感应电信号之差进行模数转换。当第二控制子电路44控制开关晶体管T4逐个开启后，计算电路30就可以得到每相邻两个感应电路10输出的感应电信号之差，从而得到每相邻两个感应电路10接收到的光信号差异，进而可以得到光强的空间分布图，以进一步得到指纹的信息。
需要说明的是，在检测基板的边缘位置，会有一些感应电路10之间的差异无法准确检测的情况，如，第一行最后一个感应电路10的输出端与第二行最后一个感应电路10的输出端之间连接有电容，而这两个感应电路10的输出端是连接同一条信号读取线RLm，因此，计算电路在计算时，会认为这两个感应电路10接收到的光信号是相同的。为此，计算电路获取指纹信息时，可以不再计算第一列和最后一列感应电路10处对应的指纹信息。
作为本公开的另一方面，提供一种指纹检测方法，用于指纹检 测装置中，所述指纹检测装置包括检测基板和信号转换器20，如上所述，所述检测基板包括排列成多行和多列多个像素，如图3所示，每个像素中设置有感应电路10，感应电路10用于接收光信号并基于接收的光信号输出相应的感应电信号；信号转换器20包括多个模数转换器21，每个模数转换器21对应一列感应电路10。所述指纹检测方法包括：通过控制电路40获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器21；以及通过所述模数转换器21对来自相应感应电路的感应电信号与所述共模信号之差进行模数转换。
在任一感应电路10所对应的检测阶段，获取包括该感应电路10在内的至少两个感应电路输出的感应电信号的共模分量，并根据获得的共模分量向感应电路10所对应的模数转换器21的信号输入端In提供输入信号和/或向感应电路10所对应的模数转换器21的参考端提供参考信号，以使模数转换器21的信号输入端In与参考端Ref接收到的信号之差等于相应感应电路10输出的感应电信号与所述共模分量之差。该过程可以由上述控制电路40执行。
模数转换器21对其信号输入端In接收到的输入信号与参考端Ref接收到的参考信号之差进行模数转换。
同一列中不同感应电路10所对应的检测阶段互不交叠。
在本公开中，由于在任一感应电路10的检测阶段，该感应电路10对应的模数转换器21的信号输入端In与参考端Ref接收到的信号之差为感应电路10输出的感应信号与共模分量之差，因此，相当于消除了至少一部分感应电路10输出的感应电信号的共模分量，从而减少了共模分量对模数转换器21的动态范围的占用，进而提高了模数转换器21的转换精度，从而不需要使用高数位的模数转换器就可以提高指纹识别的精度。
在一些实施例中，如图4所示，每个模数转换器21的信号输入端与相应列中各感应电路10的输出端相连。指纹检测周期包括第一指纹检测子周期和第二指纹检测子周期，每个感应电路10的检测阶段包括分别位于第一指纹检测子周期和第二指纹检测子周期中的第 一检测子阶段和第二检测子阶段。第二指纹检测子周期在所述第一指纹检测子周期之后。在同一个指纹检测周期中，任意一个第一检测子阶段均先于所有的第二检测子阶段。控制电路40可以包括比较子电路41、多个开关子电路42和第一控制子电路43。通过控制电路40获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器21包括：第一指纹检测子周期中，通过比较子电路41获取至少部分感应电路输出的感应电信号，并将获取的感应电信号中的最小一个作为参考信号提供至开关子电路42；以及在第二指纹检测子周期中，通过所述第一控制子电路43控制所述开关子电路42将所述参考信号提供至相应的模数转换器21的参考端。在第一指纹检测子周期中，第一控制子电路43控制开关子电路42将接地信号提供至相应的模数转换器的参考端。
上述“在任一感应电路10所对应的检测阶段，获取包括该感应电路10在内的至少两个感应电路10输出的感应电信号的共模分量，并根据获得的共模分量向感应电路10所对应的模数转换器21的信号输入端In提供输入信号和/或向感应电路10所对应的模数转换器21的参考端Ref提供参考信号”包括：第一指纹检测子周期中，获取每个感应电路10在其第一检测子阶段输出的感应电信号，并将其中最小的一者作为所述参考信号；在第二指纹检测子周期中，在每个感应电路10的第二检测子阶段，将所述参考信号输出至各模数转换器21的参考端。之后，根据各所述模数转换器21的输出信号判断任意相邻两个感应电路10输出的感应电信号之差，并根据任意相邻两个感应电路10输出电信号之差确定任意相邻两个感应电路10接收到的光信号的差异，从而确定指纹图像。
感应电路10可以在驱动电路的驱动下，逐行输出感应电信号，驱动过程以及指纹检测原理已在上文描述，这里不再赘述。
在一些实施例中，每个模数转换器21的信号输入端与相应列中各感应电路10的输出端相连，每个模数转换器21的参考端接地。如图5所示，所述控制电路包括：沿预定顺序依次串联的多个电容C， 每个电容C的两端分别与相邻两个感应电路10的输出端相连；与多个感应电路10一一对应的多个开关晶体管T4，每个开关晶体管的第一极与相应的感应电路10的输出端相连，第二极接地；以及与每个开关晶体管T4的控制极相连的第二控制子电路40。指纹检测周期包括第一指纹检测子周期和第二指纹检测子周期；每个感应电路10的检测阶段包括位于第一指纹检测子周期中的第一检测子阶段和位于第二指纹检测子周期中的第二检测子阶段；同一检测阶段中，第一检测子阶段位于第二检测子阶段之前；不同感应电路10的第二检测子阶段互不交叠。
上述“在任一感应电路所对应的检测阶段，获取包括该感应电路10在内的至少两个感应电路10输出的感应信号的共模分量，并根据获得的共模分量向感应电路10所对应的模数转换器21的信号输入端In提供输入信号和/或向感应电路10所对应的模数转换器21的参考端Ref提供参考信号”包括：
在第一指纹检测子周期，在每个感应电路10的第一检测子阶段，向相应的开关晶体管T4的控制极提供关断信号。在第二指纹检测子周期，在每个感应电路10的第二检测子阶段，向相应的开关晶体管T4的控制极提供开启信号。之后，根据各所述模数转换器21的输出信号判断任意相邻两个感应电路10输出的感应电信号之差，并根据任意相邻两个感应电路10输出电信号之差确定任意相邻两个感应电路10接收到的光信号的差异，从而确定指纹图像。
感应电路10可以在驱动电路的驱动下，逐行输出感应电信号，驱动过程以及指纹检测原理已在上文描述，这里不再赘述。
需要说明的是，本公开中的控制电路可以通过硬件和/或软件的方式来实现。例如，控制电路可以实现为处理器和存储程序的存储器，处理器在执行存储器中存储的程序时可实现控制电路中各组件(例如，比较子电路、开关子电路、第一控制子电路和第二控制子电路等)的功能。
可以理解的是，以上实施方式仅仅是为了说明本公开的原理而采用的示例性实施方式，然而本公开并不局限于此。对于本领域内的 普通技术人员而言，在不脱离本公开的精神和实质的情况下，可以做出各种变型和改进，这些变型和改进也视为本公开的保护范围。

Claims (18)

  1. 一种指纹检测装置，包括检测基板和信号转换器，所述检测基板包括排列成多行和多列的多个像素，每个像素中包括感应电路，所述感应电路构造为接收光信号并基于接收的光信号输出感应电信号；所述信号转换器包括多个模数转换器，每个模数转换器连接一列感应电路，
    其中，所述指纹检测装置还包括控制电路，所述控制电路与所述感应电路和所述模数转换器相连，并且构造为：获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器，并且
    所述模数转换器构造为对来自相应感应电路的感应电信号与所述共模信号之差进行模数转换。
  2. 根据权利要求1所述的指纹检测装置，其中，所述模数转换器包括信号输入端和参考端，
    所述控制电路构造为将关于所述共模分量的信息提供至所述模数转换器的信号输入端和参考端中的一者，使得所述模数转换器的信号输入端与参考端接收到的信号之差等于相应感应电路的感应电信号与所述共模信号之差。
  3. 根据权利要求2所述的指纹检测装置，其中
    每个模数转换器的信号输入端与相应列中各感应电路的输出端相连，
    所述控制电路包括：
    比较子电路，构造为在第一指纹检测子周期中，获取至少部分感应电路输出的感应电信号，并将获取的感应电信号中的最小一个作为参考信号进行输出；
    与所述多个模数转换器一一对应的多个开关子电路，所述开关子电路的第一输入端与所述比较子电路的输出端相连，所述开关 子电路的输出端与相应的模数转换器的参考端相连；以及
    第一控制子电路，构造为在第二指纹检测子周期中，控制每个开关子电路的第一输入端与输出端导通以输出所述参考信号，其中，所述第二指纹检测子周期在所述第一指纹检测子周期之后。
  4. 根据权利要求3所述的指纹检测装置，其中，所述开关子电路的第二输入端接地，所述第一控制子电路还构造为在第一指纹检测子周期中控制每个开关子电路的第二输入端与输出端导通。
  5. 根据权利要求2所述的指纹检测装置，其中，每个模数转换器的信号输入端与相应列中各感应电路的输出端相连，每个模数转换器的参考端接地；
    所述控制电路包括：
    依次串联的多个电容，每个电容的两端分别与相邻两个感应电路的输出端相连；
    与多个感应电路一一对应的多个开关晶体管，所述开关晶体管的第一极与相应的感应电路的输出端相连，所述开关晶体管的第二极接地；以及
    与每个开关晶体管的控制极相连的第二控制子电路，所述第二控制子电路构造为在第一指纹检测子周期，为开关晶体管的控制极提供关断信号；并在第二指纹检测子周期，为开关晶体管的控制极提供开启信号，所述第二指纹检测子周期的起始时间在所述第一指纹检测子周期的起始时间之后。
  6. 根据权利要求1至5中任意一项所述的指纹检测装置，还包括计算电路，所述计算电路与各模数转换器相连，并且构造为根据各模数转换器的输出信号判断任意相邻两个感应电路输出的感应电信号之差，并根据任意相邻两个感应电路输出的感应电信号之差确定指纹图像。
  7. 根据权利要求1至5中任意一项所述的指纹检测装置，其中，所述感应电路包括：
    光敏二极管，其阳极与低电平信号端相连；
    第一晶体管，其控制极与所述感应电路的重置端相连，第一极与高电平信号端相连，第二极与所述光敏二极管的阴极相连；
    第二晶体管，其控制极与所述光敏二极管的阴极相连，第一极与所述高电平信号端相连；以及
    第三晶体管，其控制极与所述感应电路的扫描端相连，第一极与所述第二晶体管的第二极相连，第二极与所述感应电路的输出端相连；
    其中，每个感应电路的输出端与电流源相连。
  8. 根据权利要求1至5中任意一项所述的指纹检测装置，其中，所述信号转换器还包括与多个模数转换器一一对应连接的多个放大器，所述放大器的输出端与相应的模数转换器的信号输入端相连，所述放大器的输入端与相应列的感应电路的输出端相连。
  9. 根据权利要求3所述的指纹检测装置，其中，所述比较子电路仅获取所述检测基板上指纹所覆盖范围中的感应电路输出的感应电信号，并将所获取的感应电信号中的最小一个作为所述参考信号输出。
  10. 根据权利要求3所述的指纹检测装置，其中，所述比较子电路通过检测各子像素的亮度来获取亮度最小的像素，并将获取的像素中的感应电路输出的感应电信号作为所述参考信号输出。
  11. 一种指纹检测方法，用于指纹检测装置中，所述指纹检测装置包括检测基板和信号转换器，所述检测基板包括排列成多行和多列的多个像素，每个像素中包括感应电路，所述感应电路构造为接收光信号并基于所接收的光信号输出感应电信号；所述信号转换器包括 多个模数转换器，每个模数转换器连接一列所述感应电路，
    其中，所述指纹检测方法包括：
    通过控制电路获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器，以及
    通过所述模数转换器对来自相应感应电路的感应电信号与所述共模信号之差进行模数转换。
  12. 根据权利要求11所述的指纹检测方法，其中，所述模数转换器包括信号输入端和参考端，
    将关于所述共模分量的信息提供至所述多个模数转换器包括：将关于所述共模分量的信息提供至所述模数转换器的信号输入端和参考端中的一者，使得所述模数转换器的信号输入端与参考端接收到的信号之差等于相应感应电路的感应电信号与所述共模信号之差。
  13. 根据权利要求12所述的指纹检测方法，其中，每个模数转换器的信号输入端与相应列中各感应电路的输出端相连，所述控制电路包括比较子电路、开关子电路和第一控制子电路，
    通过控制电路获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器包括：
    第一指纹检测子周期中，通过比较子电路获取至少部分感应电路输出的感应电信号，并将获取的感应电信号中的最小一个作为参考信号提供至开关子电路；以及
    在第二指纹检测子周期中，通过所述第一控制子电路控制所述开关子电路将所述参考信号提供至相应的模数转换器的参考端，所述第二指纹检测子周期在所述第一指纹检测子周期之后。
  14. 根据权利要求13所述的指纹检测方法，其中，在第一指纹检测子周期中，所述第一控制子电路控制开关子电路将接地信号提供 至相应的模数转换器的参考端。
  15. 根据权利要求12所述的指纹检测方法，其中，每个模数转换器的信号输入端与相应列中各感应电路的输出端相连，每个模数转换器的参考端接地；
    所述控制电路包括：依次串联的多个电容，每个电容的两端分别与相邻两个感应电路的输出端相连；与多个感应电路一一对应的多个开关晶体管，所述开关晶体管的第一极与相应的感应电路的输出端相连，所述开关晶体管的第二极接地；与每个开关晶体管的控制极相连的第二控制子电路，
    通过控制电路获取所述多个像素中的至少一部分的感应电路输出的感应电信号的共模分量，并将关于所述共模分量的信息提供至所述多个模数转换器包括：在第一指纹检测子周期，通过第二控制子电路为开关晶体管的控制极提供关断信号；并在第二指纹检测子周期，通过第二控制子电路为开关晶体管的控制极提供开启信号，所述第二指纹检测子周期的起始时间在所述第一指纹检测子周期的起始时间之后。
  16. 根据权利要求11所述的指纹检测方法，其中，所述指纹检测装置还包括计算电路，所述指纹检测方法还包括：
    通过所述计算电路根据各模数转换器的输出信号判断任意相邻两个感应电路输出的感应电信号之差，并根据任意相邻两个感应电路输出的感应电信号之差确定指纹图像。
  17. 根据权利要求13所述的指纹检测方法，其中，所述比较子电路仅获取所述检测基板上指纹所覆盖范围中的感应电路输出的感应电信号，并将所获取的感应电信号中的最小一个作为所述参考信号输出。
  18. 根据权利要求13所述的指纹检测方法，其中，所述比较子 电路通过检测各子像素的亮度来获取亮度最小的像素，并将获取的像素中的感应电路输出的感应电信号作为所述参考信号输出。
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