WO2020253588A1 - 指纹识别装置、显示面板、显示装置和指纹识别方法 - Google Patents

指纹识别装置、显示面板、显示装置和指纹识别方法 Download PDF

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Publication number
WO2020253588A1
WO2020253588A1 PCT/CN2020/095365 CN2020095365W WO2020253588A1 WO 2020253588 A1 WO2020253588 A1 WO 2020253588A1 CN 2020095365 W CN2020095365 W CN 2020095365W WO 2020253588 A1 WO2020253588 A1 WO 2020253588A1
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WIPO (PCT)
Prior art keywords
transistor
fingerprint
control
electrode
output
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PCT/CN2020/095365
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English (en)
French (fr)
Inventor
丁小梁
王海生
刘英明
王鹏鹏
张平
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京东方科技集团股份有限公司
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Publication of WO2020253588A1 publication Critical patent/WO2020253588A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0414—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using force sensing means to determine a position
    • 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
    • G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing

Definitions

  • the present disclosure relates to the field of display technology, and in particular to a fingerprint identification device, a display panel, a display device and a fingerprint identification method.
  • the under-screen fingerprint recognition technology refers to the technology of stacking the fingerprint recognition device and the display circuit of the display panel to realize fingerprint recognition in a specific area on the display panel.
  • the under-screen fingerprint recognition technology in related technologies mainly includes two methods: photoelectric recognition and ultrasonic recognition.
  • the principle of ultrasonic fingerprint recognition is mainly to emit ultrasonic waves, then receive the reflected echo from the finger, and obtain fingerprint information according to the analysis of the reflected echo.
  • embodiments of the present disclosure provide a fingerprint identification device applied to a display panel, and the fingerprint identification device includes:
  • the pressure sensing circuit is used to generate ultrasonic waves and sense the ultrasonic changes brought about by the fingerprint pressing, and generate corresponding fingerprint electrical signals according to the ultrasonic changes;
  • the control circuit is respectively electrically connected to the output control terminal and the pressure sensing circuit, and is used to control the output of the fingerprint electrical signal under the control of the output control signal; the output control terminal is used to provide the output control signal, wherein
  • the output fingerprint electrical signal is the fingerprint electrical signal corresponding to the ultrasonic echo signal directly generated by fingerprint reflection.
  • control circuit includes a control transistor; the output control terminal includes a first output control terminal;
  • the control electrode of the control transistor is electrically connected to the first output control terminal, the first electrode of the control transistor is electrically connected to the fingerprint electrical signal output terminal of the pressure sensing circuit, and the second electrode of the control transistor is electrically connected to The bias voltage terminal is electrically connected;
  • the pressure sensing circuit is used to output the fingerprint electrical signal through the fingerprint electrical signal output terminal.
  • the output control terminal further includes a second output control terminal
  • the control circuit also includes a second transistor and an amplifying sub-circuit
  • the control electrode of the second transistor is electrically connected to the second output control terminal, the first electrode of the second transistor is electrically connected to the fingerprint electrical signal output terminal of the pressure sensing circuit, and the first electrode of the second transistor
  • the two poles are electrically connected with the control end of the amplifying sub-circuit.
  • the output control terminal further includes a third output control terminal;
  • the amplifying sub-circuit includes a third transistor and a fourth transistor;
  • the fingerprint identification device further includes an identification circuit;
  • the control terminal of the third transistor is the control terminal of the amplifying sub-circuit; the first electrode of the third transistor is electrically connected to the first common electrode, and the second electrode of the third transistor is connected to the control terminal of the fourth transistor.
  • the control electrode of the fourth transistor is electrically connected to the third output control terminal, and the second electrode of the fourth transistor is electrically connected to the read line;
  • the identification circuit is electrically connected to the reading line, and is used for detecting fingerprint information according to the fingerprint electrical signal on the reading line.
  • the pressure-sensitive circuit includes a driving electrode, a piezoelectric layer, and a receiving electrode arranged in a stack, the driving electrode is electrically connected to a second common electrode, and the receiving electrode is used to output the fingerprint electrical signal.
  • the embodiments of the present disclosure also provide a fingerprint identification device applied to a display panel.
  • the fingerprint identification device includes a pressure sensitive circuit, a control circuit, and an identification circuit,
  • the pressure-sensitive circuit includes a driving electrode, a piezoelectric layer, and a receiving electrode arranged in a stack, the driving electrode is electrically connected to a second common electrode, and the receiving electrode is used to output the fingerprint electrical signal;
  • the control circuit includes a control transistor, a second transistor, a third transistor, and a fourth transistor; the output control terminal includes a first output control terminal, a second output control terminal, and a third output control terminal;
  • the control electrode of the control transistor is electrically connected to the first output control terminal, the first electrode of the control transistor is electrically connected to the receiving electrode of the pressure sensing circuit, and the second electrode of the control transistor is electrically connected to a bias voltage Terminal electrical connection;
  • the control electrode of the second transistor is electrically connected to the second output control terminal, the first electrode of the second transistor is electrically connected to the receiving electrode of the pressure sensing circuit, and the second electrode of the second transistor is electrically connected to The control electrode of the third transistor is electrically connected;
  • the first electrode of the third transistor is electrically connected to the first common electrode, and the second electrode of the third transistor is electrically connected to the first electrode of the fourth transistor;
  • the control electrode of the fourth transistor is electrically connected to the third output control terminal, and the second electrode of the fourth transistor is electrically connected to the read line;
  • the identification circuit is electrically connected to the reading line, and is used for detecting fingerprint information according to the fingerprint electrical signal on the reading line.
  • the embodiments of the present disclosure also provide a display panel, including the fingerprint identification device described in any one of the above.
  • the display panel includes a plurality of pixels
  • the driving circuit of each pixel includes a plurality of thin film transistors
  • the transistors in the control circuit of the fingerprint identification device include a control transistor, a second transistor, and a third transistor.
  • the fourth transistors, at least part of the thin film transistors are multiplexed as transistors in the control circuit.
  • an embodiment of the present disclosure also provides a display device, including the display panel described in any one of the above.
  • the embodiments of the present disclosure also provide a fingerprint identification method, which is applied to the fingerprint identification device of any one of the above, and the fingerprint identification cycle includes an ultrasonic generation time period and a sampling time period set in sequence; the method includes The following steps:
  • the pressure sensing circuit senses the ultrasonic change brought about by the fingerprint pressing and generates the corresponding fingerprint electrical signal; under the control of the output control signal, the control circuit controls the output of the fingerprint electrical signal .
  • the output control signal includes a first output control signal, and the first output control terminal is used to provide the first output control signal.
  • the step of controlling the output of the fingerprint electrical signal by the control circuit under the control of the output control signal includes:
  • the control transistor In the sampling period, under the control of the first output control signal, the control transistor is turned off to output the fingerprint electrical signal.
  • the output control signal further includes a second output control signal and a third output control signal.
  • Output control signal, the second output control terminal is used to provide the second output control signal, the third output control terminal is used to provide the third output control signal;
  • the fingerprint recognition cycle also includes The detection time period after the sampling time period;
  • the fingerprint identification method further includes:
  • the second transistor is turned on to write the fingerprint electrical signal into the control electrode of the third transistor, and the third transistor amplifies the Fingerprint electrical signal;
  • the fourth transistor is turned on to write the fingerprint electrical signal amplified by the third transistor into the reading line, and the identification circuit is based on the reading The electrical signal on the line detects fingerprint information.
  • the control circuit controlling the output of the fingerprint electrical signal under the control of the output control signal includes: the control circuit controlling the pressure sensing circuit to output at least during one rising half cycle Part of the fingerprint electrical signal.
  • FIG. 1 is a schematic diagram of a pressure sensitive circuit in an embodiment of the present disclosure
  • Figure 2 is a circuit diagram of a fingerprint identification device in an embodiment of the present disclosure
  • FIG. 3 is a schematic structural diagram of a display panel in an embodiment of the present disclosure.
  • FIG. 4 is a schematic structural diagram of another display panel in an embodiment of the present disclosure.
  • Figure 5 is a flowchart of a fingerprint identification method in an embodiment of the present disclosure
  • FIG. 6 is a driving timing diagram of the fingerprint identification device in an embodiment of the present disclosure.
  • the embodiments of the present disclosure provide a fingerprint identification device, a display panel, a display device, and a fingerprint identification method to solve the problem of multiple reflections of ultrasonic waves in the ultrasonic fingerprint identification process, which reduces the accuracy of fingerprint identification.
  • the embodiment of the present disclosure provides a fingerprint identification device, which is applied to a display panel, as shown in FIG. 1, and includes a pressure sensing circuit 110 and a control circuit 120.
  • the pressure sensing circuit 110 is used to generate ultrasonic waves and sense the changes in the ultrasonic waves caused by the fingerprint being pressed, and generate corresponding fingerprint electrical signals according to the ultrasonic changes.
  • the pressure sensing circuit 110 may include an independent ultrasonic transmitter sub-circuit and an ultrasonic receiver sub-circuit, wherein the ultrasonic transmitter sub-circuit is used for transmitting ultrasonic waves, and the ultrasonic receiving sub-circuit is used for sensing
  • the ultrasonic waves (or echoes) reflected by the fingerprints generate corresponding fingerprint electrical signals according to the ultrasonic changes in the echoes.
  • the pressure sensitive circuit 110 may also include an integrated ultrasonic transceiver sub-circuit.
  • the pressure-sensitive circuit 110 includes a driving electrode 111, a piezoelectric layer 112, and a receiving electrode (Rx) 113 that are stacked, and the driving electrode 111 is electrically connected to the second common electrode 131.
  • the material of the piezoelectric layer 112 can be a piezoelectric polymer, such as PVDF (polyvinylidene fluoride), piezoelectric ceramics, such as PZT (lead zirconate titanate), etc.
  • PVDF polyvinylidene fluoride
  • PZT lead zirconate titanate
  • the driving electrode 111 is also called the transmitting electrode (Tx).
  • Tx transmitting electrode
  • the second common electrode 131 provides an alternating driving voltage
  • the second common electrode 131 applies the alternating driving voltage to the piezoelectric layer 112 through the driving electrode 111. Due to the piezoelectric effect, the piezoelectric layer 112 can generate ultrasonic waves under the driving of the alternating driving voltage.
  • the receiving electrode 113 is used to receive echo signals and output fingerprint electrical signals.
  • the second common electrode 131 applies a constant value of driving voltage to the piezoelectric layer 112 through the driving electrode 111.
  • the piezoelectric layer 112 generates electric charges, and in this way, an echo signal corresponding to the echo can also be generated.
  • the echo signal is the fingerprint electrical signal and can be output through the receiving electrode 113.
  • the curved arrow 1 represents the emitted ultrasonic wave
  • the curved arrow 2 represents the ultrasonic wave (ie, the echo) that is transmitted to the piezoelectric layer 112 after being reflected by the fingerprint.
  • the fingerprint includes two features of valley 118 and ridge 119, these two features are different in the reflection of ultrasound. In this way, the information of valley 118 and ridge 119 can be determined by analyzing the fingerprint electrical signal corresponding to the echo, thereby obtaining the fingerprint information.
  • the control circuit 120 is electrically connected to the output control terminal and the pressure sensing circuit 110 respectively, and the control circuit 120 is used to control the output of the fingerprint electrical signal under the control of the output control signal.
  • the output control terminal is used to provide an output control signal.
  • the control circuit 120 works under the control of the output control signal to control the output time of the fingerprint electrical signal.
  • the display panel usually includes a multi-layer structure and functional film, so ultrasonic waves may be emitted in all directions and reflected at the interface between each structure and the functional film. Such multiple-reflected ultrasonic waves may not accurately reflect fingerprint related information. Only the echo generated directly by the fingerprint reflection can reflect the fingerprint information most directly.
  • the output fingerprint electrical signal can be mainly the fingerprint electrical signal corresponding to the ultrasonic echo signal generated by the fingerprint reflection.
  • the fingerprint identification device of the embodiment of the present disclosure includes a pressure sensing circuit 110 and a control circuit 120.
  • the control circuit 120 can control the output of the fingerprint electrical signal under the control of the output control signal, and the output time of the fingerprint electrical signal can be controlled by the control circuit 120.
  • the ultrasonic waves reflected by the fingerprint and the ultrasonic waves reflected by other structures have different transmission paths, resulting in different time for reaching the pressure sensing circuit 110.
  • control circuit 120 includes a control transistor 121, and the control transistor 121 is used to selectively receive fingerprint electrical signals.
  • the control output terminal includes a first output control terminal, and the first output control signal provided by the first output control terminal is used to control the turning on and off of the control transistor 121.
  • control electrode of the control transistor 121 is electrically connected to the first output control end, the first electrode of the control transistor 121 is electrically connected to the fingerprint electrical signal output end of the pressure sensing circuit 110, and the second electrode of the control transistor 121 is electrically connected to The bias voltage terminal 132 is electrically connected.
  • the fingerprint electrical signal output terminal of the pressure sensing circuit 110 is used to output the fingerprint electrical signal.
  • the control transistor 121 When the control transistor 121 is in the open state, the potential at point P in the figure is equal to the potential of the bias voltage terminal 132 connected to the second pole of the control transistor 121 , That is, a fixed potential. In this way, the fingerprint electrical signal generated by the pressure sensitive circuit 110 will not be received, and when the control transistor 121 is in the off state, the potential of point P is equal to the potential of the fingerprint electrical signal output terminal of the pressure sensitive circuit 110 , Can realize the output of fingerprint electric signal.
  • the first output control terminal connected to the control electrode of the control transistor 121 controls the on and off of the control transistor 121, which can realize the control of the output time of the fingerprint electrical signal.
  • the output control terminal further includes a second output control terminal;
  • the control circuit further includes a second transistor 122 and an amplifying sub-circuit 1201; the control electrode of the second transistor 122 and the second output control terminal
  • the first pole of the second transistor 122 is electrically connected to the fingerprint electrical signal output terminal of the pressure sensing circuit 110, and the second pole of the second transistor 122 is electrically connected to the control terminal of the amplifying sub-circuit 1201. connection.
  • the output control terminal further includes a third output control terminal;
  • the amplifying sub-circuit 1201 includes a third transistor 123 and a fourth transistor 124;
  • the fingerprint identification device further includes an identification circuit 140;
  • the control terminal of the third transistor 123 is the control terminal of the amplifying sub-circuit 1201; the first electrode of the third transistor 123 is electrically connected to the first common electrode 133, and the second electrode of the third transistor 123 is electrically connected to the The first electrode of the fourth transistor 123 is electrically connected;
  • the control electrode of the fourth transistor 124 is electrically connected to the third output control terminal, and the second electrode of the fourth transistor is electrically connected to the read line 134;
  • the identification circuit 140 is electrically connected to the reading line 134 and is used for detecting fingerprint information according to the fingerprint electrical signal on the reading line 134.
  • control circuit 120 further includes a second transistor 122, a third transistor 123, and a fourth transistor 124, and the output control terminal further includes a second output control terminal and a third output control terminal.
  • control electrode of the second transistor 122 is electrically connected to the second output control terminal, and the second output control is used to provide a second output control signal for controlling the turning on and off of the second transistor 122.
  • the first electrode of the voltage sensing circuit 110 is electrically connected to the fingerprint electrical signal output terminal, and the second electrode of the second transistor 122 is electrically connected to the control electrode of the third transistor 123.
  • the second transistor 122 is used to detect the peak value of the received echo on the one hand, so as to determine the fingerprint electrical signal according to the detected peak value of the echo. On the other hand, it also plays a role in circuit protection.
  • the first electrode of the third transistor 123 is electrically connected to the first common electrode 133.
  • the first common electrode 133 may be a VDD electrode and is mainly used to provide a relatively high voltage.
  • the second electrode of the third transistor 123 is electrically connected to the fourth electrode 133.
  • the first electrode of the transistor 124 is electrically connected.
  • the third transistor 123 is equivalent to a source follower.
  • the control electrode of the third transistor 123 is electrically connected to the first electrode of the second transistor 122. It should be understood that the intensity of the fingerprint electrical signal generated by the pressure sensitive circuit 110 is relatively low. By providing the third transistor 123, the fingerprint electrical signal from the second transistor 122 can be amplified.
  • the control electrode of the fourth transistor 124 is electrically connected to the third output control terminal.
  • the third output control terminal is used to provide a third output control signal for controlling the turning on and off of the fourth transistor 124.
  • the second electrode of the fourth transistor 124 is connected to the reading Take line 134 for electrical connection.
  • the fourth transistor 124 is equivalent to a switch. When the fourth transistor 124 is turned on, the fingerprint electrical signal amplified by the third transistor 123 can be transmitted to the read line 134.
  • the fingerprint identification device further includes an identification circuit 140 which is electrically connected to the reading line 134, and the identification circuit 140 is used to detect fingerprint information according to the fingerprint electrical signal on the reading line 134, so as to complete the identification of the fingerprint information.
  • identification circuit 140 For the identification circuit 140, reference may be made to related technologies, which are not further limited and described herein.
  • the embodiment of the present disclosure also provides a fingerprint identification device, which is applied to a display panel, as shown in FIG. 1-2, the fingerprint identification device includes a pressure sensitive circuit 110, a control circuit 120, and an identification circuit 140,
  • the pressure-sensitive circuit 110 includes a driving electrode 111, a piezoelectric layer 112, and a receiving electrode 113 arranged in a stack.
  • the driving electrode 111 is electrically connected to the second common electrode 131, and the receiving electrode 113 is used to output the fingerprint electrical signal ;
  • the control circuit includes a control transistor 121, a second transistor 122, a third transistor 123, and a fourth transistor 124; the output control terminal includes a first output control terminal, a second output control terminal, and a third output control terminal;
  • the control electrode of the control transistor 121 is electrically connected to the first output control terminal, the first electrode of the control transistor 121 is electrically connected to the receiving electrode 113 of the pressure sensing circuit 110, and the second electrode of the control transistor 121
  • the pole is electrically connected to the bias voltage terminal 132;
  • the control electrode of the second transistor 122 is electrically connected to the second output control terminal, the first electrode of the second transistor 122 is electrically connected to the receiving electrode 113 of the pressure sensing circuit 110, and the second transistor 122 The second electrode of is electrically connected to the control electrode of the third transistor 123;
  • the first electrode of the third transistor 123 is electrically connected to the first common electrode 133, and the second electrode of the third transistor 123 is electrically connected to the first electrode of the fourth transistor 124;
  • the control electrode of the fourth transistor 124 is electrically connected to the third output control terminal, and the second electrode of the fourth transistor 124 is electrically connected to the read line 134;
  • the identification circuit 140 is electrically connected to the reading line 134 and is used for detecting fingerprint information according to the fingerprint electrical signal on the reading line 134.
  • An embodiment of the present disclosure provides a display panel including any one of the above fingerprint identification devices.
  • the display panel is an OLED (Organic Light-Emitting Diode, organic light-emitting diode) display panel.
  • OLED Organic Light-Emitting Diode, organic light-emitting diode
  • FIG. 3 is a schematic diagram of the structure of the display panel in this embodiment.
  • the display panel includes a first substrate 301, a first electrode 302, a piezoelectric layer (PVDF) 303, and a pixel circuit (Pixel array) 304 that are stacked.
  • EL electroluminescent layer
  • Cathode cathode layer
  • Touch layer touch layer
  • Cover package cover
  • the first electrode 302, the piezoelectric layer 303 and the electrodes in the pixel circuit 304 together form a piezoelectric sandwich structure. It can also be understood that the pixel circuit is used not only as a pixel circuit of the display circuit, but also as a second electrode of a pressure sensitive circuit. Help improve the overall integration.
  • the display panel is also an OLED display panel, but the pressure sensitive circuit is implemented by an external plug.
  • the display panel includes a stacked piezoelectric matching layer 401, a first electrode 402, a piezoelectric layer 403, a second electrode 404, a pixel circuit 405, a glass substrate 406, an optical glue 407, an electroluminescent layer 408, and a package ⁇ 409 ⁇ Cover 409.
  • the first electrode 402, the piezoelectric layer 403, and the second electrode 404 form a pressure sensitive circuit. In other words, the pressure sensitive circuit and the display circuit are independent and superimposed.
  • the first electrode is a metal electrode on the entire surface
  • one of the first electrode and the second electrode is the driving electrode of the pressure-sensitive circuit
  • the other is the receiving electrode of the pressure-sensitive circuit
  • the structure of the display panel can be adjusted according to actual conditions and is not limited to this.
  • the display panel may also be a QLED (Quantum Dot Light-Emitting Diodes) display panel, a Micro LED (micro light emitting diode) display panel, a Mini LED (mini light emitting diode) display panel, an LCD ( Various types of display panels such as Liquid Crystal Display (Liquid Crystal Display) display panels are not further limited here.
  • QLED Quantum Dot Light-Emitting Diodes
  • Micro LED micro light emitting diode
  • Mini LED mini light emitting diode
  • LCD Various types of display panels such as Liquid Crystal Display (Liquid Crystal Display) display panels are not further limited here.
  • the display panel includes a plurality of pixels
  • the driving circuit of each pixel includes a plurality of thin film transistors
  • the transistors in the control circuit of the fingerprint identification device include a control transistor, a second transistor, a third transistor, and a fourth transistor.
  • at least part of the plurality of thin film transistors are multiplexed as transistors in the control circuit.
  • the transistors in the pixel drive circuit can be selected as needed.
  • the drive circuit for each pixel on the display panel includes 5 TFTs (thin film transistors) and a PIN diode. Four of the TFTs are selected and used as the control transistor, the second transistor, the third transistor and the fourth transistor respectively.
  • the ultrasonic detection sub-circuit in the ultrasonic fingerprint identification device corresponds to the pixel drive circuit one to one.
  • an ultrasonic detection sub-circuit does not only multiplex the TFT in the driving circuit of one pixel, and it may also be that the ultrasonic detection sub-circuit in the ultrasonic fingerprint recognition device does not correspond to the driving circuit of the pixel, but only The driving circuit of some pixels is multiplexed into the ultrasonic detection sub-circuit. During implementation, further adjustments can be made according to actual needs.
  • the embodiment of the present disclosure provides a display device including any of the above display panels.
  • the display device may specifically be any one of display devices including, but not limited to, a mobile phone, a tablet computer, an e-book reader, a digital camera, a laptop portable computer, a vehicle-mounted computer, a desktop computer, and a wearable device. Since the technical solution of this embodiment includes all the technical solutions of the above-mentioned embodiment, it can at least achieve all the above-mentioned technical effects, which will not be repeated here.
  • the embodiment of the present disclosure also provides a fingerprint identification method, which is applied to the fingerprint identification device described above.
  • the fingerprint recognition cycle includes the ultrasonic generation time period and the sampling time period set in sequence.
  • the fingerprint identification method includes the following steps:
  • Step 501 During the ultrasonic generation time period, control the pressure-sensitive circuit to generate ultrasonic waves.
  • ultrasonic waves for fingerprint detection are generated.
  • the pressure sensing circuit can be controlled to generate ultrasonic waves; ultrasonic waves can also be continuously generated; ultrasonic waves can also be generated when fingerprint information needs to be collected .
  • the specific manner of generating ultrasonic waves can be referred to the above-mentioned embodiments or related technologies, which is not further limited and described herein.
  • Step 502 During the sampling time period, the pressure sensing circuit detects the ultrasonic change caused by the fingerprint pressing and generates the corresponding fingerprint electrical signal. Under the control of the output control signal, the control circuit controls the output of the Fingerprint electrical signal.
  • the emitted ultrasonic wave When the emitted ultrasonic wave is reflected by the fingerprint, there will be a certain change. At this time, the echo signal is received through the pressure sensing circuit and converted into the fingerprint electrical signal.
  • a fingerprint can be understood as being composed of two features, ridges and valleys. These two features have different reflections of ultrasonic waves. In this way, the information of the valleys or ridges of the fingerprint can be determined by judging the generated fingerprint electrical signal.
  • the time for collecting and outputting fingerprint electrical signals is further controlled by the control circuit, and the time for outputting fingerprint electrical signals is controlled.
  • the output fingerprint electrical signals can be mainly reflected by fingerprints.
  • the generated ultrasonic echo signal corresponds to the fingerprint electrical signal.
  • the fingerprint identification device of the embodiment of the present disclosure includes a pressure sensitive circuit and a control circuit.
  • the control circuit can control the output of the fingerprint electrical signal under the control of the output control signal.
  • the output time of the fingerprint electrical signal can be controlled by the control circuit.
  • the transmission path of ultrasonic waves and the ultrasonic waves reflected multiple times by other structures are different, resulting in different time for reaching the pressure-sensitive circuit.
  • the output control signal includes a first output control signal
  • the first output control terminal is used to provide the first output Control signal
  • the control transistor In the sampling period, under the control of the first output control signal, the control transistor is turned off to output the fingerprint electrical signal.
  • the potential at point P in the figure is equal to the potential of the bias voltage terminal connected to the second electrode of the control transistor, that is, a fixed potential.
  • the closing time period between the two openings of the control transistor is the sampling time period of the fingerprint electrical signal. In this way, by controlling the on and off of the control transistor, it is possible to control the output period of the fingerprint electrical signal.
  • the output control signal further includes the second output control signal and the first Three output control signals
  • the second output control terminal is used to provide the second output control signal
  • the third output control terminal is used to provide the third output control signal.
  • the method further includes:
  • the second transistor is turned on to write the fingerprint electrical signal into the control electrode of the third transistor, and the third transistor amplifies the Fingerprint electrical signal.
  • the second transistor is controlled to turn on, so that the fingerprint electrical signal that needs to be collected can pass through the second transistor and be written into the third transistor.
  • the third transistor is used to amplify the fingerprint electrical signal. It should be understood that the intensity of the fingerprint electrical signal directly generated by the pressure sensing circuit is relatively small. In order to ensure the accuracy of the fingerprint electrical signal, the fingerprint electrical signal is amplified by the third transistor.
  • the control transistor After the sampling period is over, the control transistor is turned on. From the above analysis, it can be seen that the fingerprint electrical signal generated by the pressure sensing circuit cannot be output. At this time, the second transistor can be kept on or off. The purpose of turning off the second transistor is Prevent the adverse effects of leakage and other phenomena.
  • a detection period is also included.
  • the fourth transistor is turned on to write the fingerprint electrical signal amplified by the third transistor into the reading line, and the identification circuit is based on the reading
  • the electrical signal on the line detects fingerprint information.
  • the fingerprint electrical signal amplified by the third transistor can be transmitted to the reading line, and the identification circuit can further read the fingerprint electrical signal transmitted to the reading line, and further analyze to obtain the fingerprint included therein information.
  • the process of parsing the fingerprint electrical signal can refer to related technologies, which is not further limited and described here.
  • the fingerprint electrical signal is a sinusoidal signal
  • the foregoing step 502 includes:
  • the control circuit controls the pressure sensing circuit to output at least part of the fingerprint electrical signal in a rising half cycle.
  • fingerprint electrical signals in different time periods can be collected according to requirements to obtain fingerprint information, for example, one complete signal cycle or multiple complete signal cycles can be collected.
  • the set specific time period is at least part of a rising half cycle. In this way, the amount of collected signals is relatively small, which can reduce the interference of echoes.
  • the collected is a complete rising half cycle, and the accuracy of the fingerprint electrical signal is relatively high.
  • the start time of the fingerprint signal of the rising half cycle can be determined according to the time required for the ultrasonic wave directly reflected by the fingerprint to reflect to the piezoelectric layer, and the control transistor that is turned on is controlled to turn off at this moment , And then after half a cycle of the fingerprint electrical signal, turn on the control transistor to realize the collection of the fingerprint electrical signal signal.
  • FIG. 6 is a driving timing diagram of the fingerprint identification device in an embodiment.
  • the transistors in this embodiment are all N-type transistors. Obviously, other types of transistors, such as P-type transistors, can also be selected during implementation. If you choose other types of transistors, you need to adjust the timing diagram accordingly.
  • Tx represents the signal provided to the driving electrode
  • S1 represents the first output control signal provided to the control electrode of the control transistor
  • S2 is the second output control signal provided to the control electrode of the second transistor
  • S3 is provided to the fourth The third output control signal of the control electrode of the transistor.
  • the time period t1 is the aforementioned ultrasonic generation time period.
  • an alternating driving voltage is applied to the driving electrode to cause the pressure-sensitive circuit to generate ultrasonic waves.
  • the control transistor is in an on state.
  • the states of the second transistor and the fourth transistor have no effect on the sampling process, so their states can be either on or off.
  • a constant voltage is applied to the driving electrodes.
  • the time period t2 shown in the figure is the time of ultrasonic transmission and reflection. In this time period, the ultrasonic wave reaches the fingerprint and reaches the pressure sensing circuit after reflection.
  • the t3 time period shown in the figure is the above-mentioned sampling time period. During this t3 time period, the control transistor is turned off. This time period can be understood as the sampling time period. From the above analysis, it can be seen that the fingerprint generated during the time period when the control transistor is turned off The electrical signal will be collected.
  • the collected fingerprint electrical signal needs to pass through the second transistor, so during this process, the second transistor remains on.
  • the start of the t3 period is the start of a rising half period
  • the end of the t3 period is the end of a rising half period.
  • the control transistor is turned on to end sampling, and at the same time, the second transistor can be turned off.
  • fingerprint electrical signals may have been generated, but these fingerprint electrical signals are not the fingerprint electrical signals that are expected to be collected, for example, they are not at the beginning of a rising half cycle, so the control transistor has not been turned off yet .
  • the third transistor Since the third transistor mainly functions to amplify the fingerprint electrical signal to be collected, it is in the on state during the whole process, which is not shown in the figure.
  • the time period t4 shown in the figure is the sample and hold time period. During the time period t4, the second transistor is turned off. Point N in FIG. 1 maintains the potential of the fingerprint electrical signal output terminal of the pressure-sensitive circuit 110, and waits for the fingerprint electrical signal output terminal. The potential is read.
  • the fourth transistor In the t5 time period, the fourth transistor is turned on, the fingerprint electrical signal that needs to be collected is amplified by the third transistor and then transmitted to the reading line through the fourth transistor, and the identification circuit electrically connected to the reading line reads the amplified fingerprint electrical signal And further analyze to obtain fingerprint information.

Abstract

一种指纹识别装置、显示面板、显示装置和指纹识别方法。指纹识别装置还包括：压感电路（110），用于产生超声波并感测指纹按压时带来的超声波变化，并根据该超声波变化产生相应的指纹电信号；以及，控制电路（120），分别与输出控制端和压感电路（110）电连接，用于在输出控制信号的控制下，控制输出指纹电信号；输出控制端用于提供输出控制信号，其中，所述输出的指纹电信号为直接经过指纹反射产生的超声回波信号对应的指纹电信号。

Description

指纹识别装置、显示面板、显示装置和指纹识别方法
相关申请的交叉引用
本申请主张在2019年6月20日在中国提交的中国专利申请号No.201910538218.5的优先权，其全部内容通过引用包含于此。
技术领域
本公开涉及显示技术领域，尤其涉及一种指纹识别装置、显示面板、显示装置和指纹识别方法。
背景技术
屏下指纹识别技术是指将指纹识别装置与显示面板的显示电路层叠设置以实现在显示面板上的特定区域实现指纹识别的技术。相关技术中的屏下指纹识别技术主要包括光电识别和超声波识别两种方式。其中，超声波指纹识别的原理主要为发射超声波，然后接受手指的反射回波，根据对反射回波的解析获取指纹信息。
发明内容
第一方面，本公开实施例提供了一种指纹识别装置，应用于显示面板，所述指纹识别装置包括：
压感电路，用于产生超声波并感测指纹按压时带来的超声波变化，并根据该超声波变化产生相应的指纹电信号；以及，
控制电路，分别与输出控制端和所述压感电路电连接，用于在输出控制信号的控制下，控制输出所述指纹电信号；所述输出控制端用于提供所述输出控制信号，其中，所述输出的指纹电信号为直接经过指纹反射产生的超声回波信号对应的指纹电信号。
可选的，所述控制电路包括控制晶体管；所述输出控制端包括第一输出控制端；
所述控制晶体管的控制极与所述第一输出控制端电连接，所述控制晶体 管的第一极与所述压感电路的指纹电信号输出端电连接，所述控制晶体管的第二极与偏置电压端电连接；
所述压感电路用于通过所述指纹电信号输出端输出所述指纹电信号。
可选的，所述输出控制端还包括第二输出控制端；
所述控制电路还包括第二晶体管和放大子电路；
所述第二晶体管的控制极与所述第二输出控制端电连接，所述第二晶体管的第一极与所述压感电路的指纹电信号输出端电连接，所述第二晶体管的第二极与所述放大子电路的控制端电连接。
可选的，所述输出控制端还包括第三输出控制端；所述放大子电路包括第三晶体管和第四晶体管；所述指纹识别装置还包括识别电路；
所述第三晶体管的控制极为所述放大子电路的控制端；所述第三晶体管的第一极与第一公共电极电连接，所述第三晶体管的第二极与所述第四晶体管的第一极电连接；
所述第四晶体管的控制极与所述第三输出控制端电连接，所述第四晶体管的第二极与读取线电连接；
所述识别电路与所述读取线电连接，且用于根据所述读取线上的指纹电信号检测指纹信息。
可选的，所述压感电路包括层叠设置的驱动电极、压电层和接收电极，所述驱动电极与第二公共电极电连接，所述接收电极用于输出所述指纹电信号。
第二方面，本公开实施例还提供了一种指纹识别装置，应用于显示面板，所述指纹识别装置包括压感电路、控制电路和识别电路，
所述压感电路包括层叠设置的驱动电极、压电层和接收电极，所述驱动电极与第二公共电极电连接，所述接收电极用于输出所述指纹电信号；
所述控制电路包括控制晶体管、第二晶体管、第三晶体管和第四晶体管；所述输出控制端包括第一输出控制端、第二输出控制端和第三输出控制端；
所述控制晶体管的控制极与所述第一输出控制端电连接，所述控制晶体管的第一极与所述压感电路的接收电极电连接，所述控制晶体管的第二极与偏置电压端电连接；
所述第二晶体管的控制极与所述第二输出控制端电连接，所述第二晶体管的第一极与所述压感电路的接收电极电连接，所述第二晶体管的第二极与所述第三晶体管的控制极电连接；
所述第三晶体管的第一极与第一公共电极电连接，所述第三晶体管的第二极与所述第四晶体管的第一极电连接；
所述第四晶体管的控制极与所述第三输出控制端电连接，所述第四晶体管的第二极与读取线电连接；
所述识别电路与所述读取线电连接，且用于根据所述读取线上的指纹电信号检测指纹信息。
第三方面，本公开实施例还提供了一种显示面板，包括以上任一项所述的指纹识别装置。
可选的，所述显示面板包括多个像素，每一所述像素的驱动电路包括多个薄膜晶体管，在所述指纹识别装置的控制电路中的晶体管包括控制晶体管、第二晶体管、第三晶体管和第四晶体管中的一个或多个的情况下，所述薄膜晶体管中的至少部分复用为所述控制电路中的晶体管。
第四方面，本公开实施例还提供了一种显示装置，包括以上任一项所述的显示面板。
第五方面，本公开实施例还提供了一种指纹识别方法，应用于以上任一项所述的指纹识别装置，指纹识别周期包括依次设置的超声波产生时间段和采样时间段；所述方法包括以下步骤：
在所述超声波产生时间段，控制压感电路产生超声波；
在所述采样时间段，通过所述压感电路感测指纹按压时带来的超声波变化并产生相应的指纹电信号；在所述输出控制信号的控制下，控制电路控制输出所述指纹电信号。
可选的，在所述指纹识别装置为上述控制电路包括控制晶体管的指纹识别装置的情况下，所述输出控制信号包括第一输出控制信号，所述第一输出控制端用于提供所述第一输出控制信号；
在所述采样时间段，所述在所述输出控制信号的控制下，控制电路控制输出所述指纹电信号步骤包括：
在所述采样时间段，在所述第一输出控制信号的控制下，所述控制晶体管关闭，以输出所述指纹电信号。
可选的，在所述指纹识别装置为上述控制电路还包括第二晶体管、第三晶体管和第四晶体管的指纹识别装置的情况下，所述输出控制信号还包括第二输出控制信号和第三输出控制信号，所述第二输出控制端用于提供所述第二输出控制信号，所述第三输出控制端用于提供所述第三输出控制信号；所述指纹识别周期还包括设置于所述采样时间段之后的检测时间段；所述指纹识别方法还包括：
在所述采样时间段，在所述第二输出控制信号的控制下，第二晶体管打开，以将所述指纹电信号写入第三晶体管的控制极，并通过所述第三晶体管放大所述指纹电信号；
在所述检测时间段，在所述第三输出控制信号的控制下，第四晶体管打开，以将经所述第三晶体管放大的指纹电信号写入读取线，识别电路根据所述读取线上的电信号检测指纹信息。可选的，在所述采样时间段，所述在所述输出控制信号的控制下，控制电路控制输出所述指纹电信号，包括：控制电路控制所述压感电路输出一个上升半周期中至少部分的指纹电信号。
附图说明
为了更清楚地说明本公开实施例的技术方案，下面将对本公开实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本公开的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获取其他的附图。
图1是本公开一实施例中压感电路的示意图；
图2是本公开一实施例中指纹识别装置的电路图；
图3是本公开一实施例中一种显示面板的结构示意图；
图4是本公开一实施例中另一种显示面板的结构示意图；
图5是本公开一实施例中指纹识别方法的流程图；
图6是本公开一实施例中指纹识别装置的驱动时序图。
具体实施方式
下面将结合本公开实施例中的附图，对本公开实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本公开一部分实施例，而不是全部的实施例。基于本公开中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获取的所有其他实施例，都属于本公开保护的范围。
本公开实施例提供一种指纹识别装置、显示面板、显示装置和指纹识别方法，以解决超声波指纹识别过程中的超声波由于多次反射，导致指纹的识别准确程度降低的问题。
本公开实施例提供了一种指纹识别装置，该指纹识别装置应用于显示面板，如图1所示，包括压感电路110和控制电路120。
压感电路110用于产生超声波并感测指纹按压时带来的超声波变化，并根据该超声波变化产生相应的指纹电信号。
在一个可选的具体实施方式中，该压感电路110可以包括独立的超声波发射子电路和超声波接收子电路，其中，超声波发射子电路用于发射超声波，而超声波接收子电路则用于感测经指纹反射后的超声波(或称回波)，并根据回波中的超声波变化产生相应的指纹电信号。
在另一个可选的具体实施方式中，该压感电路110也可以包括集成的超声波收发子电路。
如图2所示，压感电路110包括层叠设置的驱动电极111、压电层112和接收电极(Rx)113，驱动电极111与第二公共电极131电连接。
压电层112的材料可以选择压电聚合物，例如PVDF(聚偏氟乙烯)，压电陶瓷，例如PZT(锆钛酸铅)等，具体可参考相关技术，此处不作进一步限定。
驱动电极111又称发射电极(Tx)，在需要发射超声波时，第二公共电极131提供一交变驱动电压，第二公共电极131通过驱动电极111向压电层112施加该交变驱动电压，由于压电效应，压电层112在该交变驱动电压的驱动下能够产生超声波。
接收电极113用于接收回波信号并输出指纹电信号。在接收回波时，第 二公共电极131通过驱动电极111向压电层112施加一恒定值的驱动电压，此时，当经指纹反射的回波加载在压电层112上时，由于压电效应，压电层112会产生电荷，这样，也就能生成与回波相对应的回波信号，该回波信号即为指纹电信号，并能够通过接收电极113输出。
请参阅图2，图2中曲线箭头1代表发射的超声波，曲线箭头2代表经指纹反射后再次传递至压电层112的超声波(即回波)。
由于指纹包括谷118和脊119两种特征，这两种特征对于超声波的反射是不同的，这样，通过对回波对应的指纹电信号进行解析能够确定谷118和脊119的信息，从而获得指纹信息。
控制电路120分别与输出控制端和压感电路110电连接，控制电路120用于在输出控制信号的控制下，控制输出指纹电信号。
输出控制端用于提供输出控制信号，该控制电路120在输出控制信号的控制下工作，以实现对指纹电信号的输出时间的控制。
显示面板通常包括多层结构和功能膜层，所以超声波可能向各个方向发射并在各结构和功能膜层的界面处发生反射，这种经过多次反射的超声波可能无法准确反映指纹的相关信息，而只有直接经过指纹反射产生的回波才能最直接的反应指纹的信息。
应当理解的是，在不同界面处发生反射所产生的回波是难以分离的，但是沿不同路径反射的回波的传递长度是不同的，所以抵达压感电路110所需的时间也是不同的，因此，通过对输出的指纹电信号的时间进行控制，能够使得输出的指纹电信号主要为经过指纹反射产生的超声回波信号对应的指纹电信号。
本公开实施例的指纹识别装置包括压感电路110和控制电路120，控制电路120能在输出控制信号的控制下，控制输出指纹电信号，可以通过控制电路120控制指纹电信号的输出时间，由于经指纹反射的超声波和经其他结构多次反射的超声波的传递路径不同，导致其抵达压感电路110处的时间不同。
这样，通过对于指纹电信号的输出时间进行控制，可以实现输出高质量的指纹电信号，减少对多次反射的回波产生的指纹电信号的输出，有助于提 高输出的指纹电信号的质量，降低因超声波多次反射对指纹识别结果可能带来的干扰。
可选的，控制电路120包括控制晶体管121，该控制晶体管121用于实现对于指纹电信号的选择性接收。该控制输出端包括第一输出控制端，第一输出控制端提供的第一输出控制信号用于控制该控制晶体管121的开启和关闭。
如图1所示，控制晶体管121的控制极与第一输出控制端电连接，控制晶体管121的第一极与压感电路110的指纹电信号输出端电连接，控制晶体管121的第二极与偏置电压端132电连接。
压感电路110的指纹电信号输出端用于输出指纹电信号，当控制晶体管121处于打开状态时，图中P点的电位等于控制晶体管121的第二极所连接的偏置电压端132的电位，也就是一个固定电位，这样，压感电路110所产生的指纹电信号不会被接收，而当控制晶体管121处于关闭状态时，P点的电位等于压感电路110的指纹电信号输出端的电位，能够实现指纹电信号的输出。
这样，通过与控制晶体管121的控制极相连的第一输出控制端控制该控制晶体管121的开启和关闭，能够实现对于指纹电信号输出时间的控制。
可选的，所述输出控制端还包括第二输出控制端；所述控制电路还包括第二晶体管122和放大子电路1201；所述第二晶体管122的控制极与所述第二输出控制端电连接，所述第二晶体管122的第一极与所述压感电路110的指纹电信号输出端电连接，所述第二晶体管122的第二极与所述放大子电路1201的控制端电连接。
可选的，所述输出控制端还包括第三输出控制端；所述放大子电路1201包括第三晶体管123和第四晶体管124；所述指纹识别装置还包括识别电路140；
所述第三晶体管123的控制极为所述放大子电路1201的控制端；所述第三晶体管123的第一极与第一公共电极133电连接，所述第三晶体管123的第二极与所述第四晶体管123的第一极电连接；
所述第四晶体管124的控制极与所述第三输出控制端电连接，所述第四 晶体管的第二极与读取线134电连接；
所述识别电路140与所述读取线134电连接，且用于根据所述读取线134上的指纹电信号检测指纹信息。
可选的，控制电路120还包括第二晶体管122、第三晶体管123、第四晶体管124，输出控制端还包括第二输出控制端和第三输出控制端。
请继续参阅图1，第二晶体管122的控制极与第二输出控制端电连接，该第二输出控制的用于提供控制第二晶体管122开启和关闭的第二输出控制信号，第二晶体管122的第一极与压感电路110的指纹电信号输出端电连接，第二晶体管122的第二极与第三晶体管123的控制极电连接。
该第二晶体管122一方面用于实现对接收到回波的峰值检测，从而根据所检测到的回波峰值，确定指纹电信号。另一方面，还起到电路保护的作用。
第三晶体管123的第一极与第一公共电极133电连接，该第一公共电极133可以是VDD电极，主要用于提供一相对较高的电压，第三晶体管123的第二极与第四晶体管124的第一极电连接。
该第三晶体管123相当于一个源随器，第三晶体管123的控制极与第二晶体管122的第一极电连接，应当理解的是，压感电路110产生的指纹电信号的强度相对较低，通过设置该第三晶体管123，能够放大来自第二晶体管122的指纹电信号。
第四晶体管124的控制极与第三输出控制端电连接，该第三输出控制端用于提供控制第四晶体管124开启和关闭的第三输出控制信号，第四晶体管124的第二极与读取线134电连接。
该第四晶体管124相当于一个开关，当该第四晶体管124打开时，经第三晶体管123放大后的指纹电信号能够传递至读取线134。
该指纹识别装置还包括识别电路140，识别电路140与读取线134电连接，该识别电路140用于根据读取线134上的指纹电信号检测指纹信息，从而完成指纹信息的识别。该识别电路140具体可参考相关技术，此处不作进一步限定和描述。
本公开实施例还提供了一种指纹识别装置，该指纹识别装置应用于显示面板，如图1-2所示，所述指纹识别装置包括压感电路110、控制电路120和 识别电路140，
所述压感电路110包括层叠设置的驱动电极111、压电层112和接收电极113，所述驱动电极111与第二公共电极131电连接，所述接收电极113用于输出所述指纹电信号；
所述控制电路包括控制晶体管121、第二晶体管122、第三晶体管123和第四晶体管124；所述输出控制端包括第一输出控制端、第二输出控制端和第三输出控制端；
所述控制晶体管121的控制极与所述第一输出控制端电连接，所述控制晶体管121的第一极与所述压感电路110的接收电极113电连接，所述控制晶体管121的第二极与偏置电压端132电连接；
所述第二晶体管122的控制极与所述第二输出控制端电连接，所述第二晶体管122的第一极与所述压感电路110的接收电极113电连接，所述第二晶体管122的第二极与所述第三晶体管123的控制极电连接；
所述第三晶体管123的第一极与第一公共电极133电连接，所述第三晶体管123的第二极与所述第四晶体管124的第一极电连接；
所述第四晶体管124的控制极与所述第三输出控制端电连接，所述第四晶体管124的第二极与读取线134电连接；
所述识别电路140与所述读取线134电连接，且用于根据所述读取线134上的指纹电信号检测指纹信息。
本公开实施例提供了一种显示面板，该显示面板包括以上任一项的指纹识别装置。
由于本实施例的技术方案包括了上述实施例的全部技术方案，因此至少能实现上述全部技术效果，此处不再赘述。
如图3所示，在一个具体实施方式中，该显示面板为OLED(Organic Light-Emitting Diode，有机发光二极管)显示面板。
图3为该具体实施方式中显示面板的结构示意图，该显示面板包括层叠设置的第一衬底(substrate)301、第一电极302、压电层(PVDF)303、像素电路(Pixel array)304、电致发光层(EL)305、阴极层(Cathode)306、第二衬底(substrate)307、触控层(Touch layer)308和封装盖板(Cover)309。
第一电极302、压电层303和像素电路304中的电极共同构成压电三明治结构，也可以理解为像素电路不仅作为显示电路的像素电路，还作为压感电路的第二电极使用，这样，有助于提高整体的集成度。
如图4所示，在另一个具体实施方式中，该显示面板同样为OLED显示面板，但是压感电路通过外挂实现。
具体的，该显示面板包括层叠设置的压电匹配层401、第一电极402、压电层403、第二电极404、像素电路405、玻璃基板406、光学胶407、电致发光层408、封装盖板409。其中，第一电极402、压电层403、第二电极404形成压感电路。也就是说，压感电路与显示电路是独立的且叠加设置。
上述两个具体实施方式中，第一电极为整面的金属电极，且第一电极和第二电极中的一个为压感电路的驱动电极，另一个为压感电路的接收电极。
此外，显示面板的结构可以根据实际情况作出调整，并不局限于此。
应当理解的是，该显示面板还可以是QLED(Quantum Dot Light-Emitting Diodes，量子点发光二极管)显示面板、Micro LED(微型发光二极管)显示面板、Mini LED(迷你发光二极管)显示面板、LCD(Liquid Crystal Display，液晶显示器)显示面板等各种类型的显示面板，此处不作进一步限定。
可选的，显示面板包括多个像素，每一像素的驱动电路包括多个薄膜晶体管，在指纹识别装置的控制电路中的晶体管包括控制晶体管、第二晶体管、第三晶体管和第四晶体管中的一个或多个的情况下，所述多个薄膜晶体管中的至少部分复用为控制电路中的晶体管。
通过复用显示面板像素的驱动电路(或称像素驱动电路)中的晶体管，有助于提高显示面板的集成程度以及降低成本。
实施时，可以根据需要选用像素的驱动电路中的晶体管，例如，在一个具体实施方式中，显示面板上的每一像素的驱动电路包括5个TFT(薄膜晶体管)和一个PIN二极管，使用时，选用了其中四个TFT，且分别作为上述控制晶体管、第二晶体管、第三晶体管和第四晶体管。超声指纹识别装置中的超声波检测子电路与像素的驱动电路一一对应。
进一步的，还可能是一个超声波检测子电路并非仅复用一个像素的驱动电路中的TFT，也可能是超声指纹识别装置中的超声波检测子电路并非与像 素的驱动电路一一对应，而是仅由部分像素的驱动电路复用为超声波检测子电路。实施时可以根据实际需求做出进一步的调整。
本公开实施例提供了一种显示装置，包括以上任一种的显示面板。
该显示装置具体可以是包括但不限于手机、平板电脑、电书阅读器、数码相机、膝上型便携计算机、车载电脑、台式计算机、可穿戴设备等显示装置中的任一种。由于本实施例的技术方案包括了上述实施例的全部技术方案，因此至少能实现上述全部技术效果，此处不再赘述。
本公开实施例还提供了一种指纹识别方法，应用于以上所述的指纹识别装置。指纹识别周期包括依次设置的超声波产生时间段和采样时间段。
如图5所示，该指纹识别方法包括以下步骤：
步骤501：在所述超声波产生时间段，控制压感电路产生超声波。
超声波产生时间段内，产生用于指纹检测的超声波，本实施例中，可以在检测到手指时，控制压感电路产生超声波；也可以持续产生超声波；还可以在需要采集指纹信息的时候产生超声波。产生超声波的具体方式可参考上述实施例或相关技术，此处不作进一步限定和描述。
步骤502：在所述采样时间段，通过所述压感电路感测指纹按压时带来的超声波变化并产生相应的指纹电信号，在所述输出控制信号的控制下，控制电路控制输出所述指纹电信号。
当发出的超声波经过指纹反射后会发生一定的变化，此时，通过压感电路接收回波信号，并转换为指纹电信号。
指纹可以理解成由脊和谷两种特征组成，这两种特征对于超声波的反射是不同的，这样，通过对生成的指纹电信号进行判断能够确定指纹的谷或脊的信息。
应当理解的是，在不同界面处发生反射所产生的回波是难以分离的，但是沿不同路径反射的回波的传递长度是不同的，所以抵达压感电路所需的时间也是不同的。
本实施例中进一步通过控制电路控制采集输出指纹电信号的时间，对输出指纹电信号的时间进行控制，通过采集特定时间段内的指纹电信号，能够使得输出的指纹电信号主要为经过指纹反射产生的超声回波信号对应的指纹 电信号。
本公开实施例的指纹识别装置包括压感电路和控制电路，控制电路能在输出控制信号的控制下，控制输出指纹电信号，可以通过控制电路控制指纹电信号的输出时间，由于经指纹反射的超声波和经其他结构多次反射的超声波的传递路径不同，导致其抵达压感电路处的时间不同。
这样，通过对于指纹电信号的输出时间进行控制，可以实现输出高质量的指纹电信号，减少对多次反射的回波产生的指纹电信号的输出，有助于提高输出的指纹电信号的质量，降低因超声波多次反射对指纹识别结果可能带来的干扰。
可选的，在所述指纹识别装置为上述包括控制晶体管的指纹识别装置的情况下，所述输出控制信号包括第一输出控制信号，所述第一输出控制端用于提供所述第一输出控制信号，上述步骤502包括：
在所述采样时间段，在所述第一输出控制信号的控制下，所述控制晶体管关闭，以输出所述指纹电信号。
在控制晶体管打开的情况下，图中P点的电位等于控制晶体管的第二极所连接的偏置电压端的电位，也就是一个固定电位。
应当理解的是，在处于压感电路处于采集状态时，只要有回波反射至压电层，就会产生指纹电信号，但是，在控制晶体管处于开启状态时，压感电路所产生的指纹电信号无法发送出来，只有当控制晶体管处于关闭状态时，P电的电位等于压感电路的指纹电信号输出端的电位，才能够实现指纹电信号的输出。
可以理解为，控制晶体管两次打开之间的关闭时间段即为指纹电信号的采样时间段。这样，通过控制该控制晶体管的开启和关闭，能够实现对指纹电信号的输出时间段的控制。
可选的，在所述指纹识别装置为上述包括第二晶体管、第三晶体管、第四晶体管和识别电路的指纹识别装置的情况下，，所述输出控制信号还包括第二输出控制信号和第三输出控制信号，所述第二输出控制端用于提供所述第二输出控制信号，所述第三输出控制端用于提供所述第三输出控制信号，该方法还包括：
在所述采样时间段，在所述第二输出控制信号的控制下，第二晶体管打开，以将所述指纹电信号写入第三晶体管的控制极，并通过所述第三晶体管放大所述指纹电信号。
在该采样时间段控制第二晶体管打开，这样，所需采集的指纹电信号能够通过第二晶体管，并写入第三晶体管。
第三晶体管用于放大该指纹电信号，应当理解的是，压感电路直接产生的指纹电信号强度相对较小，为了保证指纹电信号的精度，通过第三晶体管对该指纹电信号进行放大。
在采样时间段结束之后，控制晶体管打开，由上述分析可知，压感电路后续产生的指纹电信号无法被输出，此时，第二晶体管可以保持开启，也可以关闭，关闭第二晶体管的目的在于防止漏电等现象带来不利影响。
在采样时间段之后还包括检测时间段。
在所述检测时间段，在所述第三输出控制信号的控制下，第四晶体管打开，以将经所述第三晶体管放大的指纹电信号写入读取线，识别电路根据所述读取线上的电信号检测指纹信息。
当第四晶体管开启后，经由第三晶体管放大后的指纹电信号能够传递至读取线，识别电路可以进一步读取传递至读取线的指纹电信号，并进一步进行解析以获取其中包括的指纹信息。这一对指纹电信号进行解析的过程可参考相关技术，此处不作进一步限定和描述。
可选的，所述指纹电信号为正弦信号，上述步骤502包括：
控制电路控制所述压感电路输出一个上升半周期中至少部分的指纹电信号。
实施时，可以根据需求采集不同时间段内的指纹电信号，以获取指纹信息，例如可以采集一个完整的信号周期或多个完整的信号周期等。
本实施例中，设定的特定时间段为一个上升的半周期中的至少部分，这样，采集的信号量相对较少，能够减少回波的干扰。
在一个可选的具体实施方式中，采集的为一个完整的上升半周期，指纹电信号的准确度相对较高。
实施时，首先确定上升半周期的指纹信号的起始时间，该起始时间可以 根据直接经过指纹反射的超声波反射至压电层所需的时间来确定，并控制开启的控制晶体管在这个时刻关闭，然后在指纹电信号的半个周期后，开启控制晶体管，实现对指纹电信号信号的采集。
如图6所示，图6为一实施例中指纹识别装置的驱动时序图，本实施例中的各晶体管均为N型管，显然，实施时也可以选择其他类型的晶体管，例如P型管，如果选择其他类型的晶体管，则需要对时序图做出相应的调整。
下面对指纹识别装置在一个指纹识别周期的具体工作过程做进一步描述。
图中Tx代表提供至驱动电极的信号，S1代表提供至控制晶体管的控制极的第一输出控制信号，S2为提供至第二晶体管的控制极的第二输出控制信号，S3为提供至第四晶体管的控制极的第三输出控制信号。
t1时间段为上述超声波产生时间段，在这一过程中，驱动电极被施加一交变的驱动电压，以使压感电路产生超声波，此时，控制晶体管处于开启状态。这一时间段内，第二晶体管和第四晶体管的状态对采样过程没有影响，所以其状态可以是开启，也可以是关闭。在产生超声波之后，驱动电极被施加一恒定电压。
图中所示t2时间段是超声波传递和反射的时间，这一时间段内，超声波抵达指纹处，并在反射后抵达压感电路。
图中所示t3时间段为上述采样时间段，在该t3时间段内，控制晶体管关闭，这一时间段可以理解为采样时间段，由上述分析可知，控制晶体管关闭的时间段内产生的指纹电信号才会被采集。
所采集的指纹电信号需要通过第二晶体管，所以这一过程中，第二晶体管保持开启状态。
以指纹电信号为正弦信号，且采集半个上升半周期的指纹电信号为例，则t3时间段的起点是一个上升半周期的起点，t3时间段的终点是一个上升半周期的终点，在该上升半周期的终点，打开控制晶体管以结束采样，同时，可以关闭第二晶体管。
应当理解的是，在t2时间段的末期，可能已经产生了指纹电信号，但是这些指纹电信号不是希望被采集的指纹电信号，例如，并非位于一个上升半周期的起点，所以控制晶体管尚未关闭。
由于第三晶体管主要起到放大所需采集的指纹电信号的作用，所以整个过程中均处于开启状态，图中未示出。
图中所示t4时间段为采样保持时间段，在该t4时间段内，第二晶体管关闭，图1中N点保持压感电路110的指纹电信号输出端的电位，等待该指纹电信号输出端的电位被读取。
在t5时间段，第四晶体管开启，所需采集的指纹电信号经第三晶体管放大后通过第四晶体管传递至读取线，与读取线电连接的识别电路读取放大后的指纹电信号并进一步解析获得指纹信息。
以上，仅为本公开的具体实施方式，但本公开的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本公开揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本公开的保护范围之内。因此，本公开的保护范围应以权利要求的保护范围为准。

Claims (13)

  1. 一种指纹识别装置，应用于显示面板，所述指纹识别装置包括：
    压感电路，用于产生超声波并感测指纹按压时带来的超声波变化，并根据该超声波变化产生相应的指纹电信号；以及，
    控制电路，分别与输出控制端和所述压感电路电连接，用于在输出控制信号的控制下，控制输出所述指纹电信号；所述输出控制端用于提供所述输出控制信号，其中，所述输出的指纹电信号为直接经过指纹反射产生的超声回波信号对应的指纹电信号。
  2. 如权利要求1所述的指纹识别装置，其中，所述控制电路包括控制晶体管；所述输出控制端包括第一输出控制端；
    所述控制晶体管的控制极与所述第一输出控制端电连接，所述控制晶体管的第一极与所述压感电路的指纹电信号输出端电连接，所述控制晶体管的第二极与偏置电压端电连接；
    所述压感电路用于通过所述指纹电信号输出端输出所述指纹电信号。
  3. 如权利要求2所述的指纹识别装置，其中，所述输出控制端还包括第二输出控制端；
    所述控制电路还包括第二晶体管和放大子电路；
    所述第二晶体管的控制极与所述第二输出控制端电连接，所述第二晶体管的第一极与所述压感电路的指纹电信号输出端电连接，所述第二晶体管的第二极与所述放大子电路的控制端电连接。
  4. 如权利要求3所述的指纹识别装置，其中，所述输出控制端还包括第三输出控制端；所述放大子电路包括第三晶体管和第四晶体管；所述指纹识别装置还包括识别电路；
    所述第三晶体管的控制极为所述放大子电路的控制端；所述第三晶体管的第一极与第一公共电极电连接，所述第三晶体管的第二极与所述第四晶体管的第一极电连接；
    所述第四晶体管的控制极与所述第三输出控制端电连接，所述第四晶体管的第二极与读取线电连接；
    所述识别电路与所述读取线电连接，且用于根据所述读取线上的指纹电信号检测指纹信息。
  5. 如权利要求1至4中任一权利要求所述的指纹识别装置，其中，所述压感电路包括层叠设置的驱动电极、压电层和接收电极，所述驱动电极与第二公共电极电连接，所述接收电极用于输出所述指纹电信号。
  6. 一种指纹识别装置，应用于显示面板，所述指纹识别装置包括压感电路、控制电路和识别电路，
    所述压感电路包括层叠设置的驱动电极、压电层和接收电极，所述驱动电极与第二公共电极电连接，所述接收电极用于输出所述指纹电信号；
    所述控制电路包括控制晶体管、第二晶体管、第三晶体管和第四晶体管；所述输出控制端包括第一输出控制端、第二输出控制端和第三输出控制端；
    所述控制晶体管的控制极与所述第一输出控制端电连接，所述控制晶体管的第一极与所述压感电路的接收电极电连接，所述控制晶体管的第二极与偏置电压端电连接；
    所述第二晶体管的控制极与所述第二输出控制端电连接，所述第二晶体管的第一极与所述压感电路的接收电极电连接，所述第二晶体管的第二极与所述第三晶体管的控制极电连接；
    所述第三晶体管的第一极与第一公共电极电连接，所述第三晶体管的第二极与所述第四晶体管的第一极电连接；
    所述第四晶体管的控制极与所述第三输出控制端电连接，所述第四晶体管的第二极与读取线电连接；
    所述识别电路与所述读取线电连接，且用于根据所述读取线上的指纹电信号检测指纹信息。
  7. 一种显示面板，包括权利要求1至6中任一项所述的指纹识别装置。
  8. 如权利要求7所述的显示面板，其中，所述显示面板包括多个像素，每一所述像素的驱动电路包括多个薄膜晶体管，在所述指纹识别装置的控制电路中的晶体管包括控制晶体管、第二晶体管、第三晶体管和第四晶体管中的一个或多个的情况下，所述多个薄膜晶体管中的至少部分复用为所述控制电路中的晶体管。
  9. 一种显示装置，包括权利要求7或8所述的显示面板。
  10. 一种指纹识别方法，应用于权利要求1至6中任一项所述的指纹识别装置，指纹识别周期包括依次设置的超声波产生时间段和采样时间段；所述方法包括以下步骤：
    在所述超声波产生时间段，控制压感电路产生超声波；
    在所述采样时间段，通过所述压感电路感测指纹按压时带来的超声波变化并产生相应的指纹电信号，在所述输出控制信号的控制下，控制电路控制输出所述指纹电信号。
  11. 如权利要求10所述的指纹识别方法，其中，在所述指纹识别装置为权利要求2所述的指纹识别装置的情况下，所述输出控制信号包括第一输出控制信号，所述第一输出控制端用于提供所述第一输出控制信号；
    在所述采样时间段，所述在所述输出控制信号的控制下，控制电路控制输出所述指纹电信号步骤包括：
    在所述采样时间段，在所述第一输出控制信号的控制下，所述控制晶体管关闭，以输出所述指纹电信号。
  12. 如权利要求11所述的指纹识别方法，其中，在所述指纹识别装置为权利要求4所述的指纹识别装置的情况下，所述输出控制信号还包括第二输出控制信号和第三输出控制信号，所述第二输出控制端用于提供所述第二输出控制信号，所述第三输出控制端用于提供所述第三输出控制信号；所述指纹识别周期还包括设置于所述采样时间段之后的检测时间段；所述指纹识别方法还包括：
    在所述采样时间段，在所述第二输出控制信号的控制下，第二晶体管打开，以将所述指纹电信号写入第三晶体管的控制极，并通过所述第三晶体管放大所述指纹电信号；
    在所述检测时间段，在所述第三输出控制信号的控制下，第四晶体管打开，以将经所述第三晶体管放大的指纹电信号写入读取线，识别电路根据所述读取线上的电信号检测指纹信息。
  13. 如权利要求10所述的指纹识别方法，其中，在所述采样时间段，所述在所述输出控制信号的控制下，控制电路控制输出所述指纹电信号，包括：
    控制电路控制所述压感电路输出一个上升半周期中至少部分的指纹电信号。
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