CN110245636B - Fingerprint identification module, display panel, display device and fingerprint identification method - Google Patents
Fingerprint identification module, display panel, display device and fingerprint identification method Download PDFInfo
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- CN110245636B CN110245636B CN201910538218.5A CN201910538218A CN110245636B CN 110245636 B CN110245636 B CN 110245636B CN 201910538218 A CN201910538218 A CN 201910538218A CN 110245636 B CN110245636 B CN 110245636B
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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
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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
- G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing
Abstract
The invention provides a fingerprint identification module, a display panel, a display device and a fingerprint identification method. Fingerprint identification module still includes: the pressure sensing circuit is used for generating ultrasonic waves, sensing ultrasonic wave changes caused by fingerprint pressing and generating corresponding fingerprint electric signals according to the ultrasonic wave changes; the control circuit is respectively electrically connected with the output control end and the pressure sensing circuit and is used for controlling the output of the fingerprint electric signal under the control of the output control signal; the output control terminal is used for providing an output control signal. The fingerprint identification module of the embodiment of the invention comprises the pressure sensing circuit and the 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 quality of the output fingerprint electrical signal is improved, and the interference to the fingerprint identification result possibly caused by the multiple reflection of ultrasonic waves is reduced.
Description
Technical Field
The invention relates to the technical field of display, in particular to a fingerprint identification module, a display panel, a display device and a fingerprint identification method.
Background
Fingerprint identification technique is the technique of realizing fingerprint identification with the range upon range of setting of fingerprint identification module and display panel's display module assembly under the screen. The existing technology for identifying fingerprints under a screen mainly comprises two modes of photoelectric identification and ultrasonic identification. The principle of ultrasonic fingerprint identification is mainly to emit ultrasonic waves, then receive reflected echoes of fingers, and acquire fingerprint information according to analysis of the reflected echoes.
However, the structure of the display substrate is complex, and usually includes a plurality of structures or film layers arranged in a stacked manner, so that the ultrasonic waves may pass through multiple reflections of the structures during the transmission process, resulting in a complex received echo, and thus the accuracy of fingerprint identification is reduced.
Disclosure of Invention
The embodiment of the invention provides a fingerprint identification module, a display panel, a display device and a fingerprint identification method, and aims to solve the problem that the accuracy of fingerprint identification is reduced due to multiple reflections of ultrasonic waves in the process of ultrasonic fingerprint identification.
In a first aspect, an embodiment of the present invention provides a fingerprint identification module applied to a display panel, where the fingerprint identification module includes:
the pressure sensing circuit is used for generating ultrasonic waves, sensing ultrasonic wave changes caused by fingerprint pressing and generating corresponding fingerprint electric signals according to the ultrasonic wave changes; and the number of the first and second groups,
the control circuit is respectively electrically connected with the output control end and the pressure sensing circuit and is used for controlling and outputting the fingerprint electric signal under the control of an output control signal; the output control terminal is used for providing the output control signal.
Optionally, the control circuit comprises a control transistor; the output control end comprises a first output control end;
the control electrode of the control transistor is electrically connected with the first output control end, the first electrode of the control transistor is electrically connected with the fingerprint electrical signal output end of the pressure sensing circuit, and the second electrode of the control transistor is electrically connected with the bias voltage end;
the pressure sensing circuit is used for outputting the fingerprint electric signal through the fingerprint electric signal output end.
Optionally, the output control end further includes a second output control end and a third output control end;
the control circuit further comprises a second transistor, a third transistor and a fourth transistor, and the fingerprint identification module further comprises an identification circuit;
the control electrode of the second transistor is electrically connected with the second output control end, the first electrode of the second transistor is electrically connected with the fingerprint electrical signal output end of the pressure sensing circuit, and the first electrode of the second transistor is electrically connected with the control end of the third transistor;
a first pole of the third transistor is electrically connected to the first common electrode, and a second pole of the third transistor is electrically connected to the first pole of the fourth transistor;
a control electrode of the fourth transistor is electrically connected with the third output control end, and a second electrode of the fourth transistor is electrically connected with the reading line;
the reading circuit is electrically connected with the reading line and is used for detecting fingerprint information according to the electric signal on the reading line.
Optionally, the pressure sensing circuit includes a driving electrode, a piezoelectric layer, and a receiving electrode, which are stacked, the driving electrode is electrically connected to the second common electrode, and the receiving electrode is configured to output the fingerprint electrical signal.
In a second aspect, an embodiment of the present invention provides a display panel, including the fingerprint identification module described in any one of the above.
Optionally, the display panel includes a plurality of pixels, the driving circuit of each pixel includes a plurality of thin film transistors, and in a case that the transistors in the control circuit of the fingerprint identification module include one or more of a control transistor, a second transistor, a third transistor, and a fourth transistor, at least a part of the thin film transistors are multiplexed as the transistors in the control circuit.
In a third aspect, an embodiment of the present invention provides a display device, including the display panel described in any one of the above.
In a fourth aspect, an embodiment of the present invention provides a fingerprint identification method, which is applied to any one of the fingerprint identification modules described above, where a fingerprint identification cycle includes an ultrasonic wave generation time period and a sampling time period that are sequentially set; the method comprises the following steps:
controlling a pressure sensing circuit to generate ultrasonic waves in the ultrasonic wave generation time period;
in the sampling time period, sensing ultrasonic wave change brought by fingerprint pressing through the pressure sensing circuit and generating a corresponding fingerprint electric signal; and under the control of the output control signal, the control circuit controls and outputs the fingerprint electric signal.
Optionally, when the fingerprint identification module is a fingerprint identification module in which the control circuit includes a control transistor, the output control signal includes a first output control signal, and the first output control terminal is configured to provide the first output control signal;
in the sampling time period, the step of controlling the fingerprint electric signal to be output by the control circuit under the control of the output control signal comprises the following steps:
in the sampling time period, the control transistor is turned off under the control of the first output control signal to output the fingerprint electric signal.
Optionally, when the fingerprint identification module is a fingerprint identification module in which the control circuit further includes a second transistor, a third transistor, and a fourth transistor, the output control signal further includes a second output control signal and a third output control signal, the second output control terminal is configured to provide the second output control signal, and the third output control terminal is configured to provide the third output control signal; the fingerprint identification period further comprises a detection time period arranged after the sampling time period; the fingerprint identification method further comprises the following steps:
in the sampling time period, under the control of the second output control signal, the second transistor is switched on to write the fingerprint electric signal into a control electrode of the third transistor and amplify the fingerprint electric signal through the third transistor;
in the detection time period, under the control of the third output control signal, the fourth transistor is turned on to write the fingerprint electric signal amplified by the third transistor into a reading line, and the identification circuit detects fingerprint information according to the electric signal on the reading line.
The fingerprint identification module of the embodiment of the invention comprises a pressure sensing circuit and a control circuit, the control circuit can be under the control of output control signal, the control output fingerprint electric signal, can be through the output time of control circuit control fingerprint electric signal, because the ultrasonic wave of reflection of fingerprint is different with the transmission path of the ultrasonic wave of other structure multiple reflections, lead to its time difference that arrives at pressure sensing circuit department, thus, through controlling the output time of fingerprint electric signal, can realize exporting high-quality fingerprint electric signal, reduce the output to the echo of multiple reflections, help improving the quality of the fingerprint electric signal of output, reduce because of the interference that the ultrasonic wave multiple reflections probably brought the fingerprint identification result.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a schematic diagram of a pressure sensing circuit according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of a fingerprint recognition module according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a display panel according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of another display panel according to an embodiment of the present invention;
FIG. 5 is a flow chart of a fingerprint identification method according to an embodiment of the present invention;
FIG. 6 is a timing diagram illustrating the driving of the fingerprint recognition module according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a fingerprint identification module.
The fingerprint identification module 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 for generating ultrasonic waves, sensing ultrasonic wave changes caused by fingerprint pressing, and generating corresponding fingerprint electric signals according to the ultrasonic wave changes.
In an alternative embodiment, the pressure sensing circuit 110 may include an ultrasonic wave emitting unit and an ultrasonic wave receiving unit, wherein the ultrasonic wave emitting unit is configured to emit an ultrasonic wave, and the ultrasonic wave receiving unit is configured to sense an ultrasonic wave (or echo) reflected by the fingerprint and generate a corresponding fingerprint electrical signal according to a change of the ultrasonic wave in the echo.
In another alternative embodiment, the pressure sensing circuit 110 may also include an integrated ultrasound transceiver unit.
As shown in fig. 2, the pressure sensing circuit 110 includes a driving electrode 111, a piezoelectric layer 112, and a receiving electrode (Rx)113, which 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 selected from piezoelectric polymers, such as PVDF (polyvinylidene fluoride), piezoelectric ceramics, such as PZT (lead zirconate titanate), etc., and refer to the related art, which is not further limited herein.
The driving electrode 111 is also called as a transmitting electrode (Tx), when the ultrasonic wave needs to be transmitted, the second common electrode 131 provides an alternating driving voltage, and the second common electrode 131 applies the alternating driving voltage to the piezoelectric layer 112 through the driving electrode 111, and the piezoelectric layer 112 can generate the ultrasonic wave under the driving of the alternating driving voltage due to the piezoelectric effect.
The receiving electrode 113 is used for receiving the echo signal and outputting a fingerprint electric signal. When receiving the echo, the second common electrode 131 applies a constant driving voltage to the piezoelectric layer 112 through the driving electrode 111, and at this time, when the echo reflected by the fingerprint is applied to the piezoelectric layer 112, the piezoelectric layer 112 generates an electric charge due to the piezoelectric effect, so that an echo signal corresponding to the echo can be generated, and the echo signal is an electrical fingerprint signal and can be output through the receiving electrode 113.
Referring to fig. 2, the right-hand curved arrow in fig. 2 represents the transmitted ultrasonic waves, and the left-hand curved arrow represents the ultrasonic waves (i.e., echoes) reflected by the fingerprint and then transmitted to the piezoelectric layer 112 again.
Since the fingerprint includes two features, namely, the valley 118 and the ridge 119, which are different from each other in reflection of the ultrasonic wave, the information of the valley 118 and the ridge 119 can be determined by analyzing the fingerprint electric signal corresponding to the echo, so that the fingerprint information can be obtained.
The control circuit 120 is electrically connected to the output control terminal and the pressure sensing circuit 110, and the control circuit 120 is used for controlling the output of the fingerprint electrical signal under the control of the output control signal.
The output control terminal is used for providing an output control signal, and the control circuit 120 operates under the control of the control signal to control the output time of the fingerprint electrical signal.
The display panel generally includes a multi-layer structure and a functional film layer, so that ultrasonic waves may be emitted to all directions and reflected at the interface of each structure and functional film layer, and such multiple reflected ultrasonic waves may not accurately reflect information related to fingerprints, and only echoes generated by direct reflection of fingerprints can most directly reflect information of fingerprints.
It should be understood that echoes generated by reflection at different interfaces are difficult to separate, but the transmission lengths of the echoes reflected along different paths are different, so the time required for reaching the pressure sensing circuit 110 is also different, and therefore, by controlling the time of the output fingerprint electric signal, the output fingerprint electric signal can be mainly a fingerprint electric signal corresponding to an ultrasonic echo signal generated by reflection of a fingerprint.
The fingerprint identification module of the embodiment of the invention comprises a pressure sensing circuit 110 and a control circuit 120, wherein the control circuit 120 can control the output of a fingerprint electrical signal under the control of an output control signal, the output time of the fingerprint electrical signal can be controlled by the control circuit 120, and the time for the ultrasonic wave to reach the pressure sensing circuit 110 is different due to the fact that the transmission paths of the ultrasonic wave reflected by the fingerprint and the ultrasonic wave reflected by other structures for multiple times are different.
Therefore, the output time of the fingerprint electrical signal is controlled, so that the high-quality fingerprint electrical signal can be output, the output of the fingerprint electrical signal generated by the echo of multiple reflections is reduced, the quality of the output fingerprint electrical signal is improved, and the interference possibly brought to the fingerprint identification result due to the multiple reflections of the ultrasonic wave is reduced.
Optionally, the control circuit 120 comprises a control transistor 121, the control transistor 121 being adapted to enable selective reception of the electrical fingerprint signal. The control output terminal includes a first output control terminal, and a first output control signal provided by the first output control terminal is used for controlling the on and off of the control transistor 121.
As shown in fig. 1, a control electrode of the control transistor 121 is electrically connected to the first output control terminal, a first electrode of the control transistor 121 is electrically connected to the fingerprint electrical signal output terminal of the pressure sensing circuit 110, and a second electrode of the control transistor 121 is electrically connected to the bias voltage terminal 132.
The fingerprint electrical signal output terminal of the pressure sensing circuit 110 is used for outputting a fingerprint electrical signal, when the control transistor 121 is in an on state, the potential at the 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, i.e. a fixed potential, so that the fingerprint electrical signal generated by the pressure sensing circuit 110 is not received, and when the control transistor 121 is in an off state, the potential of the point P is equal to the potential of the fingerprint electrical signal output terminal of the pressure sensing circuit 110, so that the output of the fingerprint electrical signal can be realized.
In this way, the output control terminal connected to the control electrode of the control transistor 121 controls the on and off of the control transistor 121, thereby controlling the output time of the fingerprint electric signal.
Optionally, the 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.
Referring to fig. 1, the control electrode of the second transistor 122 is electrically connected to the second output control terminal, the second output control terminal is used for providing a second output control signal for controlling the second transistor 122 to turn on and off, the first electrode of the second transistor 122 is electrically connected to the fingerprint electrical signal output terminal of the pressure sensing circuit 110, and the first electrode of the second transistor 122 is electrically connected to the control electrode of the third transistor 123.
The second transistor 122 is used on the one hand to enable peak detection of the received echo, so that the fingerprint electrical signal is determined from the detected echo peak. On the other hand, the circuit protection function is also realized.
A first pole of the third transistor 123 is electrically connected to a first common electrode 133, the first common electrode 133 may be a VDD electrode and is mainly used for providing a relatively high voltage, and a second pole of the third transistor 123 is electrically connected to a first pole of the fourth transistor 124.
The third transistor 123 corresponds to a source follower, and a control electrode of the third transistor 123 is electrically connected to the first stage of the second transistor 122, but it should be understood that the intensity of the fingerprint electric signal generated by the pressure sensing circuit 110 is relatively low, and the fingerprint electric signal from the second transistor 122 can be amplified by providing the third transistor 123.
A control electrode of the fourth transistor 124 is electrically connected to a third output control terminal for providing a third output control signal for controlling the fourth transistor 124 to turn on and off, and a second electrode of the fourth transistor 124 is electrically connected to the read line 134.
The fourth transistor 124 is a switch, and when the fourth transistor 124 is turned on, the fingerprint electrical signal amplified by the third transistor 123 can be transmitted to the readout line 134.
This fingerprint identification module still includes identification circuit, and identification circuit is connected with reading line 134 electricity, and this discernment is used for detecting fingerprint information according to the signal of telecommunication on reading line 134 from the circuit to accomplish fingerprint information's discernment. The identification circuit may refer specifically to the related art and is not further defined and described herein.
The embodiment of the invention provides a display panel, which comprises the fingerprint identification module.
Since the technical solution of this embodiment includes all technical solutions of the above embodiments, at least all technical effects can be achieved, and details are not described here.
In one embodiment, as shown in fig. 3, the display panel is an OLED (Organic Light-Emitting Diode) display panel.
Fig. 3 is a schematic structural diagram of a display panel in this embodiment, and the display panel includes a first substrate (substrate)301, a first electrode 302, a piezoelectric layer (PVDF)303, a Pixel circuit (Pixel array)304, an Electroluminescent Layer (EL)305, a Cathode layer (Cathode)306, a second substrate (substrate)307, a Touch layer (Touch layer)308, and a Cover (Cover)309, which are stacked.
The first electrode 302, the piezoelectric layer 303 and the electrodes in the pixel circuit 304 together form a piezoelectric sandwich structure, and it can also be understood that the pixel circuit is used not only as a pixel circuit of a display unit, but also as a second electrode of a pressure sensing circuit, which contributes to improving the overall integration level.
In another embodiment, as shown in fig. 4, the display panel is also an OLED display panel, but the pressure sensing circuit is implemented by plug-in.
Specifically, the display panel includes a 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 adhesive 407, an electroluminescent unit 708, and a package cover 709, which are stacked. The first electrode 402, the piezoelectric layer 403, and the second electrode 404 form a pressure sensing circuit. That is, the pressure sensing circuit and the display unit are independent and disposed in a superposed manner.
In the two embodiments, the first electrode is a metal electrode on the whole surface, one of the first electrode and the second electrode is a driving electrode of the pressure sensing circuit, and the other is a receiving electrode of the pressure sensing circuit.
In addition, the structure of the display panel may be adjusted according to the actual situation, and is not limited thereto.
It should be understood that the Display panel may also be various types of Display panels such as a QLED Display panel, a Micro LED (Micro diode) Display panel, a Mini LED (Mini diode) Display panel, an LCD (Liquid Crystal Display) Display panel, and the like, and is not further limited herein.
Optionally, the display panel includes a plurality of pixels, the driving circuit of each pixel includes a plurality of thin film transistors, and in a case where the transistors in the control circuit of the fingerprint identification module include one or more of a control transistor, a second transistor, a third transistor, and a fourth transistor, at least a portion of the thin film transistors are multiplexed as transistors in the control circuit.
By multiplexing the transistors in the driving circuit (or called pixel driving circuit) of the display panel pixels, the integration degree of the display panel is improved and the cost is reduced.
In practice, the transistors in the driving circuit of the pixel may be selected according to the requirement, for example, in one embodiment, the driving circuit of each pixel on the display panel includes 5 TFTs (thin film transistors) and one PIN (diode), and when in use, four of the TFTs are selected and respectively used as the control transistor, the second transistor, the third transistor and the fourth transistor. Ultrasonic detection unit and pixel's drive circuit one-to-one in the supersound fingerprint identification module.
Furthermore, it is also possible that one ultrasonic detection unit does not multiplex only TFTs in the driving circuit of one pixel, but that the ultrasonic detection units in the ultrasonic fingerprint identification module do not correspond to the driving circuits of the pixels one to one, and are multiplexed into the ultrasonic detection units only by the driving circuits of some pixels. Further adjustment can be made according to actual requirements during implementation.
An embodiment of the present invention provides a display device including any one 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 electronic book reader, a digital camera, a laptop portable computer, an in-vehicle computer, a desktop computer, a wearable device, and the like. Since the technical solution of this embodiment includes all technical solutions of the above embodiments, at least all technical effects can be achieved, and details are not described here.
The embodiment of the invention also provides a fingerprint identification method which is applied to the fingerprint identification module. The fingerprint identification cycle comprises an ultrasonic wave generation time period and a sampling time period which are sequentially arranged.
As shown in fig. 5, the fingerprint identification method includes the following steps:
step 501: and controlling the pressure sensing circuit to generate ultrasonic waves in the ultrasonic wave generation time period.
In the ultrasonic wave generation time period, the ultrasonic wave for fingerprint detection is generated, and in the embodiment, the pressure sensing circuit can be controlled to generate the ultrasonic wave when the finger is detected; the ultrasonic wave can be continuously generated; ultrasonic waves can also be generated when fingerprint information needs to be acquired. The specific manner of generating the ultrasonic waves can refer to the above-mentioned embodiments or related technologies, and is not further defined and described herein.
Step 502: the sampling time quantum, through the ultrasonic wave change that brings when pressure circuit sensing fingerprint is pressed and produce corresponding fingerprint signal of telecommunication, under output control signal's control, control circuit control output the fingerprint signal of telecommunication.
When the ultrasonic wave that sends can take place certain change after the fingerprint reflection, at this moment, receive echo signal through pressure sensing circuit to convert fingerprint signal of telecommunication into.
A fingerprint is understood to be composed of two features, ridge and valley, which are different for the reflection of ultrasound, so that the information of the valley or ridge of the fingerprint can be determined by evaluating the generated electrical fingerprint signal.
It will be appreciated that echoes resulting from reflections at different interfaces are difficult to separate, but the propagation lengths of echoes reflected along different paths are different, so the time required to reach the pressure sensing circuit is also different.
Further gather the time of output fingerprint signal of telecommunication through control circuit control in this embodiment, control the time of output fingerprint signal of telecommunication, through gathering the fingerprint signal of telecommunication in the specific time quantum, can make the fingerprint signal of telecommunication of output mainly be the fingerprint signal of telecommunication that the supersound echo signal that produces through the fingerprint reflection corresponds.
The fingerprint identification module of the embodiment of the invention comprises a pressure sensing circuit and a control circuit, wherein the control circuit can control the output of a fingerprint electrical signal under the control of an output control signal, and can control the output time of the fingerprint electrical signal through the control circuit, and the time for the ultrasonic wave to reach the pressure sensing circuit is different due to the fact that the ultrasonic wave reflected by the fingerprint is different from the transmission path of the ultrasonic wave reflected by other structures for multiple times.
Therefore, the output time of the fingerprint electrical signal is controlled, so that the high-quality fingerprint electrical signal can be output, the output of the fingerprint electrical signal generated by the echo of multiple reflections is reduced, the quality of the output fingerprint electrical signal is improved, and the interference possibly brought to the fingerprint identification result due to the multiple reflections of the ultrasonic wave is reduced.
Optionally, in a case that the fingerprint identification module is the above fingerprint identification module including a control transistor, the output control signal includes a first output control signal, the first output control terminal is configured to provide the first output control signal, and step 502 includes:
in the sampling time period, the control transistor is turned off under the control of the first output control signal to output the fingerprint electric signal.
In the case where the control transistor is turned on, the potential at the point P in the figure is equal to the potential of the bias voltage terminal to which the second pole of the control transistor is connected, that is, a fixed potential.
It should be understood that when the pressure sensing circuit is in the collecting state, as long as an echo is reflected to the piezoelectric layer, a fingerprint electric signal is generated, but when the control transistor is in the on state, the fingerprint electric signal generated by the pressure sensing circuit cannot be sent out, and only when the control transistor is in the off state, the potential of the P-potential is equal to the potential of the fingerprint electric signal output end of the pressure sensing circuit, so that the output of the fingerprint electric signal can be realized.
It can be understood that the off time period between two times of turning on of the control transistor is the sampling time period of the fingerprint electric signal. Thus, by controlling the on and off of the control transistor, the control of the output period of the fingerprint electric signal can be realized.
Optionally, in a case that the fingerprint identification module is the above fingerprint identification module including the second transistor, the third transistor, the fourth transistor and the identification circuit, the output control signal further includes a second output control signal and a third output control signal, the second output control terminal is configured to provide the second output control signal, the third output control terminal is configured to provide the third output control signal, and the method further includes:
and in the sampling time period, under the control of the second output control signal, the second transistor is turned on to write the fingerprint electric signal into a control electrode of the third transistor and amplify the fingerprint electric signal through the third transistor.
And controlling the second transistor to be opened in the sampling time period, so that the fingerprint electric signal required to be acquired can pass through the second transistor and be written into the third transistor.
The third transistor is used for amplifying the fingerprint electric signal, and it should be understood that the fingerprint electric signal directly generated by the pressure sensing circuit has relatively low intensity, and is amplified by the third transistor in order to ensure the accuracy of the fingerprint electric signal.
After the sampling time period is over, the control transistor is turned off, and the analysis shows that the fingerprint electric signal subsequently generated by the pressure sensing circuit cannot be output, at this time, the second transistor can be kept on or pulled down, and the purpose of pulling down the second transistor is to prevent the adverse effect possibly brought by the phenomena of electric leakage and the like on the circuit.
A detection period is also included after the sampling period.
In the detection time period, under the control of the third output control signal, the fourth transistor is turned on to write the fingerprint electric signal amplified by the third transistor into a reading line, and the identification circuit detects fingerprint information according to the electric signal on the reading line.
When the fourth transistor is turned on, the fingerprint electric signal amplified by the third transistor can be transmitted to the reading line, and the identification circuit can further read the fingerprint electric signal transmitted to the reading line and further analyze the fingerprint electric signal to acquire the fingerprint information included in the fingerprint electric signal. The process of parsing the electrical fingerprint signal is described in reference to the related art, and is not further limited and described herein.
Optionally, the fingerprint electrical signal is a sinusoidal signal, and the step 502 includes:
the control circuit controls the pressure sensing circuit to output at least part of the fingerprint electric signal in a rising half period.
During implementation, the fingerprint electrical signals in different time periods can be collected according to requirements to acquire fingerprint information, for example, a complete signal cycle or multiple complete signal cycles can be collected.
In this embodiment, the specific time period is set to be at least part of a rising half cycle, so that the amount of the acquired signal is relatively small, and the interference of the echo can be reduced.
In a preferred embodiment, the electrical fingerprint signal is acquired for a full rise half cycle with relatively high accuracy.
When the fingerprint signal acquisition device is implemented, the starting time of the fingerprint signal of the rising half period is firstly determined, the starting time can be determined according to the time required for the ultrasonic wave directly reflected by the fingerprint to be reflected to the piezoelectric layer, the started control transistor is controlled to be closed at the moment, and then the control transistor is started after the half period of the fingerprint electric signal, so that the fingerprint electric signal acquisition is realized.
As shown in fig. 6, fig. 6 is a driving timing diagram of the fingerprint identification module in an embodiment, each transistor in the embodiment is an N-type transistor, obviously, other types of transistors, such as P-type transistors, may be selected during implementation, and if other types of transistors are selected, the timing diagram needs to be adjusted accordingly.
The specific operation of the fingerprint recognition module in a fingerprint recognition cycle is further described below.
In the figure, Tx represents a signal supplied to the driving electrode, S1 represents a first output control signal supplied to the gate of the control transistor, S2 is a second output control signal supplied to the gate of the second transistor, and S3 is a third output control signal supplied to the gate of the fourth transistor.
the time period t1 is the ultrasonic wave generation time period, in the process, an alternating driving voltage is applied to the driving electrode to enable the pressure sensing circuit to generate the ultrasonic wave, and at the time, the control transistor is in an on state. In this time period, the states of the second transistor and the fourth transistor have no influence on the sampling process, so that the states may be on or off. After the ultrasonic wave is generated, a constant voltage is applied to the driving electrodes.
The time period t2 is shown as the time when the ultrasonic wave is transmitted and reflected, and during this time period, the ultrasonic wave reaches the fingerprint and reaches the pressure sensing circuit after being reflected.
The t3 time period is the above sampling time period, and the time period t3 in which the control transistor is turned off is understood as the sampling time period, and the fingerprint electric signal generated in the time period in which the control transistor is turned off is collected according to the above analysis.
The electrical signal of the acquired fingerprint needs to pass through the second transistor, so the second transistor is kept in an opening state in the process.
Taking the fingerprint electrical signal as a sinusoidal signal and collecting the fingerprint electrical signal for half a rising half period as an example, the start point of the t3 time period is the start point of a rising half period, and the end point of the t4 time period is the end point of a rising half period, at the end point of the rising half period, the control transistor is turned on to end the sampling, and at the same time, the second transistor can be pulled down.
It will be appreciated that at the end of the time period t2, electrical fingerprint signals may have been generated, but these are not the electrical fingerprint signals that are desired to be acquired, for example, not at the beginning of a rising half-cycle, so the control transistor has not been turned off.
Since the third transistor mainly plays a role of amplifying the fingerprint electrical signal to be acquired, the third transistor is in an on state in the whole process, which is not shown in the figure.
And in a time period t5, the fourth transistor is turned on, the fingerprint electric signal to be acquired is amplified by the third transistor and then is transmitted to the reading line through the fourth transistor, and the identification circuit electrically connected with the reading line reads the amplified fingerprint electric signal and further analyzes the fingerprint electric signal to acquire fingerprint information.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. The utility model provides a fingerprint identification module is applied to display panel, its characterized in that, the fingerprint identification module includes:
the pressure sensing circuit is used for generating ultrasonic waves in an ultrasonic wave generation time period, sensing ultrasonic wave change caused by fingerprint pressing in a sampling time period and generating corresponding fingerprint electric signals according to the ultrasonic wave change, wherein the ultrasonic wave generation time period and the sampling time period are sequentially arranged in each fingerprint identification period; and the number of the first and second groups,
the control circuit is respectively electrically connected with the output control end and the pressure sensing circuit and is used for controlling and outputting the fingerprint electric signal under the control of an output control signal; the output control end is used for providing the output control signal;
the output control end comprises a second output control end and a third output control end;
the control circuit further comprises a second transistor, a third transistor and a fourth transistor, and the fingerprint identification module further comprises an identification circuit;
the control electrode of the second transistor is electrically connected with the second output control end, the first electrode of the second transistor is electrically connected with the fingerprint electrical signal output end of the pressure sensing circuit, and the first electrode of the second transistor is electrically connected with the control end of the third transistor;
a first pole of the third transistor is electrically connected to the first common electrode, and a second pole of the third transistor is electrically connected to the first pole of the fourth transistor;
a control electrode of the fourth transistor is electrically connected with the third output control end, and a second electrode of the fourth transistor is electrically connected with the reading line;
the identification circuit is electrically connected with the reading line and is used for detecting fingerprint information according to the electric signal on the reading line; wherein the content of the first and second substances,
a control electrode of the second transistor is a gate electrode of the second transistor, a first electrode of the second transistor is one of a source and a drain of the second transistor, and a second electrode of the second transistor is the other of the source and the drain of the second transistor; a control electrode of the third transistor is a gate electrode of the third transistor, a first electrode of the third transistor is one of a source and a drain of the third transistor, and a second electrode of the third transistor is the other of the source and the drain of the third transistor; a gate of the fourth transistor is a gate of the fourth transistor, a first pole of the fourth transistor is one of a source and a drain of the fourth transistor, and a second pole of the fourth transistor is the other of the source and the drain of the fourth transistor.
2. The fingerprint identification module of claim 1 wherein the control circuit comprises a control transistor; the output control end comprises a first output control end;
the control electrode of the control transistor is electrically connected with the first output control end, the first electrode of the control transistor is electrically connected with the fingerprint electrical signal output end of the pressure sensing circuit, the second electrode of the control transistor is electrically connected with the bias voltage end, the control electrode of the control transistor is the grid electrode of the control transistor, the first electrode of the control transistor is one of the source electrode and the drain electrode of the control transistor, and the second electrode of the control transistor is the other one of the source electrode and the drain electrode of the control transistor;
the pressure sensing circuit is used for outputting the fingerprint electric signal through the fingerprint electric signal output end.
3. The fingerprint identification module of any one of claims 1 to 2, wherein the pressure sensing circuit comprises a driving electrode, a piezoelectric layer and a receiving electrode, which are stacked, the driving electrode is electrically connected to the second common electrode, and the receiving electrode is configured to output the fingerprint electrical signal.
4. A display panel comprising the fingerprint recognition module of any one of claims 1 to 3.
5. The display panel of claim 4, wherein the display panel comprises a plurality of pixels, the driving circuit of each pixel comprises a plurality of thin film transistors, and at least a portion of the thin film transistors are multiplexed as transistors in the control circuit in the case that the transistors in the control circuit of the fingerprint identification module comprise one or more of a control transistor, a second transistor, a third transistor, and a fourth transistor.
6. A display device characterized by comprising the display panel according to claim 4 or 5.
7. A fingerprint identification method, which is applied to the fingerprint identification module set in any one of claims 1 to 3, wherein the fingerprint identification period comprises an ultrasonic wave generation time period and a sampling time period which are sequentially set; the method comprises the following steps:
controlling a pressure sensing circuit to generate ultrasonic waves in the ultrasonic wave generation time period;
the sampling time quantum, through the ultrasonic wave change that brings when pressure circuit sensing fingerprint is pressed and produce corresponding fingerprint signal of telecommunication, under output control signal's control, control circuit control output the fingerprint signal of telecommunication.
8. The fingerprint identification method according to claim 7, wherein in case that the fingerprint identification module is the fingerprint identification module according to claim 2, the output control signal comprises a first output control signal, and the first output control terminal is configured to provide the first output control signal;
in the sampling time period, the step of controlling the fingerprint electric signal to be output by the control circuit under the control of the output control signal comprises the following steps:
in the sampling time period, the control transistor is turned off under the control of the first output control signal to output the fingerprint electric signal.
9. The fingerprint identification method according to claim 8, wherein in case that the fingerprint identification module is the fingerprint identification module according to claim 2, the output control signal further comprises a second output control signal and a third output control signal, the second output control terminal is used for providing the second output control signal, and the third output control terminal is used for providing the third output control signal; the fingerprint identification period further comprises a detection time period arranged after the sampling time period; the fingerprint identification method further comprises the following steps:
in the sampling time period, under the control of the second output control signal, the second transistor is switched on to write the fingerprint electric signal into a control electrode of the third transistor and amplify the fingerprint electric signal through the third transistor;
in the detection time period, under the control of the third output control signal, the fourth transistor is turned on to write the fingerprint electric signal amplified by the third transistor into a reading line, and the identification circuit detects fingerprint information according to the electric signal on the reading line.
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| CN201910538218.5A CN110245636B (en) | 2019-06-20 | 2019-06-20 | Fingerprint identification module, display panel, display device and fingerprint identification method |
| PCT/CN2020/095365 WO2020253588A1 (en) | 2019-06-20 | 2020-06-10 | Fingerprint recognition device, display panel, display device, and fingerprint recognition method |
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| CN201910538218.5A CN110245636B (en) | 2019-06-20 | 2019-06-20 | Fingerprint identification module, display panel, display device and fingerprint identification method |
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| CN110245636B (en) * | 2019-06-20 | 2021-08-10 | 京东方科技集团股份有限公司 | Fingerprint identification module, display panel, display device and fingerprint identification method |
| TWI698849B (en) * | 2019-10-03 | 2020-07-11 | 友達光電股份有限公司 | Pixel circuit |
| CN110865490A (en) * | 2019-11-29 | 2020-03-06 | 上海天马微电子有限公司 | Array substrate, display panel and display device |
| WO2021109121A1 (en) * | 2019-12-06 | 2021-06-10 | 京东方科技集团股份有限公司 | Ultrasonic fingerprint recognition unit, fingerprint recognition apparatus and fingerprint recognition driving method |
| CN111709402A (en) * | 2019-12-17 | 2020-09-25 | 神盾股份有限公司 | Fingerprint sensing device |
| CN111652169A (en) * | 2020-06-09 | 2020-09-11 | 武汉华星光电技术有限公司 | Fingerprint drive circuit and display panel |
| CN115483984B (en) * | 2022-09-13 | 2024-01-12 | 维沃移动通信有限公司 | Fingerprint module, control method and device, readable storage medium and electronic equipment |
| CN115661870B (en) * | 2022-09-16 | 2024-03-15 | 深圳市汇顶科技股份有限公司 | Ultrasonic fingerprint identification method, ultrasonic fingerprint device and electronic equipment |
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| WO2020253588A1 (en) | 2020-12-24 |
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