CN110956125B - Fingerprint identification circuit, driving method thereof and touch display panel - Google Patents
Fingerprint identification circuit, driving method thereof and touch display panel Download PDFInfo
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- CN110956125B CN110956125B CN201911184056.6A CN201911184056A CN110956125B CN 110956125 B CN110956125 B CN 110956125B CN 201911184056 A CN201911184056 A CN 201911184056A CN 110956125 B CN110956125 B CN 110956125B
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- 238000003672 processing method Methods 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 10
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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
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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
- G06F3/0412—Digitisers structurally integrated in a display
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Abstract
The invention discloses a fingerprint identification circuit, a driving method thereof and a touch display panel, wherein a reset module is utilized to reset a first node before fingerprint identification, an ultrasonic transducer is controlled to emit ultrasonic waves through a control module during fingerprint identification, when a fingerprint exists, the emitted ultrasonic waves are reflected at the valley of the fingerprint due to the problem of acoustic impedance matching, and the ultrasonic waves continue to propagate at the ridge of the fingerprint. The reflected ultrasonic wave is received by the ultrasonic receiving transducer, so that the point position of the first node is changed, the input module controls the signal value of the output end of the first node according to the potential of the first node, the output module provides the signal output by the input module to the reading signal end, and the image of the fingerprint can be obtained by detecting the signal of the reading signal end. The fingerprint identification circuit adopts different ultrasonic transducers for transmitting and receiving ultrasonic waves, has a simple structure and a simple subsequent signal processing method, thereby improving the accuracy of fingerprint imaging.
Description
Technical Field
The present invention relates to the field of fingerprint identification technologies, and in particular, to a fingerprint identification circuit, a driving method thereof, and a touch display panel.
Background
In recent years, with the rapid development of touch technologies, mobile products with a biometric identification function gradually enter life and work of people, and fingerprint technologies are valued by people by virtue of unique identity characteristics. Fingerprint identification can be divided into according to the theory of operation: resistive, capacitive, infrared, ultrasonic, electromagnetic, oscillatory wave inductive, frustrated total internal reflection optical inductive, and the like.
At present, ultrasonic fingerprint identification mostly uses ultrasonic waves of the MHz level for imaging, and when the propagation speed of the ultrasonic waves in a solid exceeds 1540m/s, a transmitted signal and a received signal are usually detected at the same time. In the existing ultrasonic fingerprint identification circuit, the transmission and the reception of signals are mainly realized by using one ultrasonic transducer. The method comprises the steps of simultaneously collecting transmitted and received signals, and judging the valleys and ridges of the fingerprint by complex signal comparison and other processing methods, so that fingerprint imaging is realized. However, this fingerprint identification method is complex and has low accuracy.
Disclosure of Invention
In view of the above, the embodiments of the present invention provide a fingerprint recognition circuit, a driving method thereof, and a touch display panel, so as to implement an ultrasonic fingerprint recognition circuit with a simple structure.
The fingerprint identification circuit provided by the embodiment of the invention comprises: the ultrasonic transducer comprises an ultrasonic transducer, an input module, a control module, a reset module and an output module;
the input end of the input module is connected with a first reference voltage, the control end of the input module is connected with a first node, and the output end of the input module is connected with the input end of the output module; the input module is used for controlling the signal value of the output end of the first node according to the potential of the first node;
the control end of the output module is connected with a reading control signal, and the output end of the output module is connected with a reading signal end; the output module is used for providing the signal received by the input end of the output module to the reading signal end under the control of the reading control signal;
the input end of the control module is connected with alternating current, the control end of the control module is connected with the reading control signal, and the output end of the control module is connected with the ultrasonic transducer; the control module is used for providing alternating current for the ultrasonic transducer under the control of the reading control signal so as to enable the ultrasonic transducer to emit ultrasonic waves;
the output end of the reset module is connected with a second reference voltage, the control end of the reset module is connected with a reset control signal, and the output end of the reset module is connected with the first node; the reset module is used for providing the second reference voltage to the first node under the control of the reset control signal so as to reset the potential of the first node;
the receiving ultrasonic transducer is connected to the first node, and the receiving ultrasonic transducer is used for receiving ultrasonic waves.
Optionally, in the fingerprint identification circuit provided by the embodiment of the present invention, the input module includes a first transistor;
the grid electrode of the first transistor is connected with the first node, the first pole of the first transistor is connected with the first reference voltage, and the second pole of the first transistor is connected with the input end of the output module.
Optionally, in the fingerprint identification circuit provided by the embodiment of the present invention, the input module further includes a first capacitor;
the first capacitor is connected between the gate and the first pole of the first transistor.
Optionally, in the fingerprint identification circuit provided by the embodiment of the present invention, the reset module includes a second transistor;
the grid electrode of the second transistor is connected with the reset control signal, the first electrode of the second transistor is connected with the second reference voltage, and the second electrode of the second transistor is connected with the first node.
Optionally, in the fingerprint identification circuit provided in the embodiment of the present invention, the control module includes a third transistor;
the gate of the third transistor is connected to the read control signal, the first pole of the third transistor is connected to the alternating current, and the second pole of the third transistor is connected to the ultrasonic transducer.
Optionally, in the fingerprint identification circuit provided in the embodiment of the present invention, the output module includes a fourth transistor;
the grid electrode of the fourth transistor is connected with the reading control signal, the first electrode of the fourth transistor is connected with the output end of the input module, and the second electrode of the fourth transistor is connected with the reading signal end.
Optionally, in the fingerprint identification circuit provided by the embodiment of the present invention, all the switch transistors are N-type transistors or P-type transistors.
Optionally, in the fingerprint identification circuit provided by the embodiment of the present invention, the transmitting ultrasonic transducer and the receiving ultrasonic transducer are disposed on the same layer; or alternatively, the first and second heat exchangers may be,
the transmit ultrasonic transducer and the receive ultrasonic transducer are stacked.
Correspondingly, the embodiment of the invention also provides a touch display panel which comprises a display panel and a plurality of fingerprint identification circuits provided by the embodiment of the invention.
Correspondingly, the embodiment of the invention also provides a driving method of the fingerprint identification circuit, which comprises the following steps:
a reset stage, wherein the reset module provides the second reference voltage to the first node under the control of the reset control signal so as to reset the potential of the first node; the input module outputs a signal under the control of the first node;
a reading stage, wherein the control module provides alternating current to the ultrasonic transducer under the control of the reading control signal; the ultrasonic transducer emits ultrasonic waves; when a finger touch is performed, the ultrasonic wave receiving transducer receives ultrasonic waves reflected by the finger and changes the potential of the first node; the input module controls the signal value of the output end of the first node according to the potential of the first node; the output module provides the signal output by the input module to the reading signal end under the control of the reading control signal.
The invention has the following beneficial effects:
according to the fingerprint identification circuit, the driving method thereof and the touch display panel provided by the embodiment of the invention, before fingerprint identification is performed, the reset module is utilized to reset the first node, when fingerprint identification is performed, the control module is used for controlling the ultrasonic transducer to emit ultrasonic waves, when the fingerprint exists, the emitted ultrasonic waves are reflected at the valley of the fingerprint due to the problem of acoustic impedance matching, and the ultrasonic waves continue to propagate at the ridge of the fingerprint. The reflected ultrasonic wave is received by the ultrasonic receiving transducer, so that the point position of the first node is changed, the input module controls the signal value of the output end of the first node according to the potential of the first node, the output module provides the signal output by the input module to the reading signal end, and the image of the fingerprint can be obtained by detecting the signal of the reading signal end. According to the fingerprint identification circuit provided by the embodiment of the invention, the ultrasonic wave is transmitted and received by adopting different ultrasonic transducers, the structure is simple, the subsequent signal processing method is simple, and thus the accuracy of fingerprint imaging can be improved.
Drawings
FIG. 1 is a schematic diagram of an ultrasonic fingerprint recognition principle;
fig. 2 is a schematic diagram of a fingerprint identification circuit according to an embodiment of the present invention;
FIG. 3 is a second schematic diagram of a fingerprint identification circuit according to an embodiment of the present invention;
FIG. 4 is a third schematic diagram of a fingerprint identification circuit according to an embodiment of the present invention;
FIG. 5 is one of the input/output timing diagrams corresponding to the fingerprint recognition circuit shown in FIG. 4;
FIG. 6 is a second timing diagram of the input/output of the fingerprint recognition circuit shown in FIG. 4;
FIG. 7 is a schematic diagram showing the change of the surface potential of the fingerprint recognition circuit shown in FIG. 4 when the ultrasonic transducer receives ultrasonic waves;
FIG. 8 is a schematic diagram of a partial structure of a fingerprint identification circuit according to an embodiment of the present invention;
FIG. 9 is a second schematic diagram of a partial structure of a fingerprint identification circuit according to an embodiment of the present invention;
fig. 10 is a flowchart of a driving method of a fingerprint identification circuit according to an embodiment of the present invention.
Detailed Description
The principle of ultrasonic fingerprint recognition is shown in fig. 1, and the emitted ultrasonic waves are reflected at the valleys of the fingerprint due to the problem of acoustic impedance matching. At the ridges of the fingerprint, the ultrasound waves continue to propagate. By detecting the reflected ultrasonic signals, an image of the fingerprint can be obtained.
Based on the above, the invention provides a fingerprint identification circuit, a driving method thereof and a touch display panel.
In order that the above objects, features and advantages of the invention will be readily understood, a further description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. The words expressing the positions and directions described in the present invention are described by taking the drawings as an example, but can be changed according to the needs, and all the changes are included in the protection scope of the present invention. The drawings of the present invention are merely schematic representations of relative positional relationships and are not intended to represent true proportions.
It is noted that in the following description, specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than those herein described, and those skilled in the art may readily devise numerous other arrangements that do not depart from the spirit of the invention. Therefore, the present invention is not limited by the specific embodiments disclosed below. The description hereinafter sets forth the preferred embodiment for carrying out the present application, but is not intended to limit the scope of the present application in general, for the purpose of illustrating the general principles of the present application. The scope of the present application is defined by the appended claims.
The fingerprint identification circuit, the driving method thereof and the touch display panel provided by the embodiment of the invention are specifically described below with reference to the accompanying drawings.
The fingerprint identification circuit provided by the embodiment of the invention, as shown in fig. 2, comprises: the ultrasonic transducer for transmitting 01, the ultrasonic transducer for receiving 02, the input module 03, the control module 04, the reset module 05 and the output module 06;
the input end of the input module 03 is connected with a first reference voltage V1, the control end is connected with a first node N1, and the output end is connected with the input end of the output module 06; the input module 03 is used for controlling the signal value of the output end of the first node N1 according to the potential of the first node N1;
the control end of the output module 06 is connected with a read control signal read, and the output end is connected with a read signal end Out; the output module 06 is configured to provide the signal received by the input terminal thereof to the read signal terminal Out under the control of the read control signal read;
the input end of the control module 04 is connected with alternating current, the control end is connected with a read control signal read, and the output end is connected with an ultrasonic transducer 01; the control module 04 is used for providing alternating current to the ultrasonic transducer 01 under the control of the read control signal read so as to enable the ultrasonic transducer 01 to emit ultrasonic waves;
the output end of the reset module 05 is connected with a second reference voltage V2, the control end is connected with a reset control signal reset, and the output end is connected with a first node N1; the reset module 05 is configured to provide the second reference voltage V2 to the first node N1 under control of the reset control signal reset, so as to reset the potential of the first node N1;
the receiving ultrasonic transducer 02 is connected to the first node N1, and the receiving ultrasonic transducer 02 is configured to receive ultrasonic waves.
Before fingerprint identification is performed, the reset module is utilized to reset the first node, when the fingerprint identification is performed, the control module is used for controlling the ultrasonic transducer to emit ultrasonic waves, when the fingerprint exists, the emitted ultrasonic waves are reflected at the valley of the fingerprint due to the problem of acoustic impedance matching, and the ultrasonic waves continue to propagate at the ridge of the fingerprint. The reflected ultrasonic wave is received by the ultrasonic receiving transducer, so that the point position of the first node is changed, the input module controls the signal value of the output end of the first node according to the potential of the first node, the output module provides the signal output by the input module to the reading signal end, and the image of the fingerprint can be obtained by detecting the signal of the reading signal end. According to the fingerprint identification circuit provided by the embodiment of the invention, the ultrasonic wave is transmitted and received by adopting different ultrasonic transducers, the structure is simple, the subsequent signal processing method is simple, and thus the accuracy of fingerprint imaging can be improved.
The present invention will be described in detail with reference to specific examples. The present embodiment is for better explaining the present invention, but not limiting the present invention.
Optionally, in the fingerprint identification circuit provided in the embodiment of the present invention, as shown in fig. 3, the input module 03 includes a first transistor T1;
the gate of the first transistor T1 is connected to the first node N1, the first pole of the first transistor T1 is connected to the first reference voltage V1, and the second pole of the first transistor T1 is connected to the input of the output module 06.
In a specific implementation, under the control of the first node, the first transistor is turned on, the first reference voltage provides a current signal to the output module through the turned-on first transistor, and the potential of the first node determines the magnitude of the current signal.
Specifically, the first transistor may be an N-type transistor or a P-type transistor, which is not limited herein. When the first transistor is an N-type transistor, the second reference voltage is larger than the first reference voltage, and when the first transistor is a P-type transistor, the second reference voltage is smaller than the first reference voltage.
Optionally, in the fingerprint identification circuit provided by the embodiment of the present invention, as shown in fig. 4, the input module 03 further includes a first capacitor C1; the first capacitor C1 is connected between the gate and the first pole of the first transistor T1. The potential of the first node N1 is stabilized by the first capacitor C1, so that the accuracy of the fingerprint identification circuit is improved.
The above is merely illustrative of a specific structure of the input module in the fingerprint identification circuit, and the specific structure of the input module is not limited to the above structure provided in the embodiment of the present invention, but may be other structures known to those skilled in the art, and is not limited herein.
Optionally, in the fingerprint identification circuit provided in the embodiment of the present invention, as shown in fig. 3, the reset module 05 includes a second transistor T2;
the gate of the second transistor T2 is connected to the reset control signal reset, the first pole of the second transistor T2 is connected to the second reference voltage V2, and the second pole of the second transistor T2 is connected to the first node N1.
In the implementation, under the control of a reset control signal, the second transistor is turned on, the second reference voltage is provided to the first node through the turned-on second transistor, and the potential of the first node is reset, so that noise interference is reduced, and fingerprint identification accuracy is ensured.
Specifically, the second transistor may be an N-type transistor or a P-type transistor, which is not limited herein.
The above is merely illustrative of a specific structure of the reset module in the fingerprint identification circuit, and the specific structure of the reset module is not limited to the above structure provided in the embodiment of the present invention, but may be other structures known to those skilled in the art, and is not limited herein.
Optionally, in the fingerprint identification circuit provided in the embodiment of the present invention, as shown in fig. 3, the control module 04 includes a third transistor T3;
the gate of the third transistor T3 is connected to the read control signal read, the first pole of the third transistor T3 is connected to the alternating current, and the second pole of the third transistor T3 is connected to the ultrasonic transducer 01.
In particular implementations, the third transistor is turned on under control of the read control signal, and the turned-on third transistor provides an alternating current to the ultrasonic transducer to cause the ultrasonic transducer to emit ultrasonic waves.
Specifically, the third transistor may be an N-type transistor or a P-type transistor, which is not limited herein.
The above is merely illustrative of a specific structure of the control module in the fingerprint identification circuit, and the specific structure of the control module is not limited to the above structure provided in the embodiment of the present invention, but may be other structures known to those skilled in the art, and is not limited herein.
Optionally, in the fingerprint identification circuit provided in the embodiment of the present invention, as shown in fig. 3, the output module 06 includes a fourth transistor T4;
the gate of the fourth transistor T4 is connected to the read control signal read, the first pole of the fourth transistor T4 is connected to the output of the input module 03, and the second pole of the fourth transistor T4 is connected to the read signal terminal Out.
In the implementation, under the control of a reading control signal, the fourth transistor is conducted, a current signal output by an input module of the conducted third transistor is provided for a reading signal end, when no fingerprint exists, the signal of the reading signal end is kept unchanged, when the fingerprint exists, if the fingerprint corresponds to a valley, the ultrasonic transducer receives reflected ultrasonic waves, the potential of a first node changes, the current signal output by the input module changes, and the signal of the reading signal end changes; if the ridge corresponds to the ultrasonic wave, the ultrasonic wave receiving transducer cannot receive the reflected ultrasonic wave, the potential of the first node does not change, the current signal output by the input module does not change, and the signal of the reading signal end does not change.
Specifically, the fourth transistor may be an N-type transistor or a P-type transistor, which is not limited herein.
The above is merely an example of a specific structure of the output module in the fingerprint identification circuit, and the specific structure of the output module is not limited to the above structure provided in the embodiment of the present invention, but may be other structures known to those skilled in the art, and is not limited herein.
In a specific implementation, in the fingerprint identification circuit provided by the embodiment of the present invention, all the switching transistors are N-type transistors or P-type transistors, so that the manufacturing process flow of the pixel circuit can be simplified, which is not limited herein.
In the embodiment, the switching transistor may be a thin film transistor (TFT, thin Film Transistor) or a metal oxide semiconductor field effect transistor (MOS, metal Oxide Semiconductor), which is not limited herein.
The following describes the operation of the fingerprint recognition circuit according to the embodiment of the present invention, taking the fingerprint recognition circuit shown in fig. 4 as an example. And in the following description, a high level signal is denoted by 1, and a low level signal is denoted by 0.
In the pixel circuit shown in fig. 4, all the switching transistors are N-type transistors, and each N-type transistor is turned off under the action of low level and turned on under the action of high level; the corresponding circuit timing diagrams are shown in fig. 5 and 6. Specifically, when the fingerprint identification circuit works, the fingerprint identification circuit comprises two stages: a reset phase and a read phase; wherein:
in the reset stage (T1), under the control of the reset control signal reset, the second transistor T2 is turned on, the second reference voltage V2 is provided to the first node N1 through the turned-on second transistor T2, and the potential of the first node N1 is reset, so that noise interference is reduced, and accuracy of fingerprint identification is ensured. The first transistor T1 is turned on under the control of the first node N1.
In the read phase (T2), the first transistor T1 continues to be turned on under the control of the first node N1. The potential of the first node N1 is stabilized by the first capacitor C1, so that the accuracy of the fingerprint identification circuit is improved. Under the control of the read control signal read, the third transistor T3 is turned on, and the turned-on third transistor T3 supplies alternating current to the ultrasonic transducer 01 to cause the ultrasonic transducer 01 to emit ultrasonic waves. Under the control of the read control signal read, the fourth transistor T4 is turned on, and the current signal output by the third transistor T3 is provided to the read signal terminal Out, when no fingerprint exists, the signal of the read signal terminal Out remains unchanged, when a fingerprint exists, if the fingerprint corresponds to a valley, the ultrasonic transducer 02 receives the reflected ultrasonic wave, the surface potential of the ultrasonic transducer 02 changes, and the simulation result is shown in fig. 7. The surface potential of the receiving ultrasonic transducer 02 changes to cause the potential of the first node N1 to change, the current signal output by the third transistor T3 changes, and the signal of the reading signal end Out changes; if the ridge corresponds, the ultrasonic transducer 02 cannot receive the reflected ultrasonic wave, the potential of the first node N1 does not change, the current signal output by the third transistor T3 does not change, and the signal of the reading signal terminal Out does not change.
According to the fingerprint identification circuit provided by the embodiment of the invention, the ultrasonic wave is transmitted and received by adopting different ultrasonic transducers, the structure is simple, the subsequent signal processing method is simple, and thus the accuracy of fingerprint imaging can be improved.
Optionally, in the fingerprint identification circuit provided by the embodiment of the invention, as shown in fig. 8, the transmitting ultrasonic transducer 01 and the receiving ultrasonic transducer 02 are arranged in the same layer, so that the film layers with the same functions of the transmitting ultrasonic transducer and the receiving ultrasonic transducer can be prepared in the same layer, thereby simplifying the process steps.
Optionally, in the fingerprint recognition circuit provided by the embodiment of the invention, as shown in fig. 9, the transmitting ultrasonic transducer 01 and the receiving ultrasonic transducer 02 are stacked, and the receiving ultrasonic transducer 02 is located at the side close to the finger, so that the area of the fingerprint recognition circuit can be saved.
In fig. 8 and 9, the ultrasonic transducer 01 and the ultrasonic transducer 02 in the fingerprint recognition circuits are shown as examples.
In a specific implementation, in the fingerprint identification circuit provided by the embodiment of the invention, the ultrasonic transducer is preferably a voltage type ultrasonic transducer.
Based on the same inventive concept, the embodiment of the present invention further provides a driving method of a fingerprint identification circuit, as shown in fig. 10, including:
s101, in a reset stage, a reset module supplies a second reference voltage to a first node under the control of a reset control signal so as to reset the potential of the first node; the input module outputs a signal under the control of the first node;
s102, in a reading stage, the control module supplies alternating current to the ultrasonic transducer under the control of a reading control signal; the ultrasonic transducer emits ultrasonic waves; when a finger touch is performed, the ultrasonic wave reflected by the finger is received by the ultrasonic wave receiving transducer, and the potential of the first node is changed; the input module controls the signal value of the output end of the input module according to the potential of the first node; the output module provides the signal output by the input module to the reading signal end under the control of the reading control signal.
In the implementation, since the principle of the driving method for solving the problem is similar to that of the fingerprint identification circuit, the implementation of the driving method can refer to the implementation of the fingerprint identification circuit, and the repetition is omitted.
Based on the same inventive concept, the embodiment of the invention also provides a touch display panel, which comprises a display panel and a plurality of any fingerprint identification circuits provided by the embodiment of the invention. Because the principle of the touch display panel for solving the problem is similar to that of the fingerprint identification circuit, the implementation of the touch display panel can be referred to the implementation of the fingerprint identification circuit, and the repeated parts are not repeated.
In a specific implementation, in the touch display panel provided by the embodiment of the invention, the fingerprint identification circuit may be integrated in the display panel, and of course may be formed in a frame area of the display panel, or hung on the display panel, which is not limited herein.
According to the fingerprint identification circuit, the driving method thereof and the touch display panel provided by the embodiment of the invention, before fingerprint identification is performed, the reset module is utilized to reset the first node, when fingerprint identification is performed, the control module is used for controlling the ultrasonic transducer to emit ultrasonic waves, when the fingerprint exists, the emitted ultrasonic waves are reflected at the valley of the fingerprint due to the problem of acoustic impedance matching, and the ultrasonic waves continue to propagate at the ridge of the fingerprint. The reflected ultrasonic wave is received by the ultrasonic receiving transducer, so that the point position of the first node is changed, the input module controls the signal value of the output end of the first node according to the potential of the first node, the output module provides the signal output by the input module to the reading signal end, and the image of the fingerprint can be obtained by detecting the signal of the reading signal end. According to the fingerprint identification circuit provided by the embodiment of the invention, the ultrasonic wave is transmitted and received by adopting different ultrasonic transducers, the structure is simple, the subsequent signal processing method is simple, and thus the accuracy of fingerprint imaging can be improved.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (10)
1. A fingerprint identification circuit, comprising: the ultrasonic transducer comprises an ultrasonic transducer, an input module, a control module, a reset module and an output module;
the input end of the input module is connected with a first reference voltage, the control end of the input module is connected with a first node, and the output end of the input module is connected with the input end of the output module; the input module is used for controlling the signal value of the output end of the first node according to the potential of the first node;
the control end of the output module is connected with a reading control signal, and the output end of the output module is connected with a reading signal end; the output module is used for providing the signal received by the input end of the output module to the reading signal end under the control of the reading control signal;
the input end of the control module is connected with alternating current, the control end of the control module is connected with the reading control signal, and the output end of the control module is connected with the ultrasonic transducer; the control module is used for providing alternating current for the ultrasonic transducer under the control of the reading control signal so as to enable the ultrasonic transducer to emit ultrasonic waves;
the input end of the reset module is connected with a second reference voltage, the control end of the reset module is connected with a reset control signal, and the output end of the reset module is connected with the first node; the reset module is used for providing the second reference voltage to the first node under the control of the reset control signal so as to reset the potential of the first node;
the receiving ultrasonic transducer is connected to the first node, and the receiving ultrasonic transducer is used for receiving ultrasonic waves.
2. The fingerprint recognition circuit of claim 1, wherein the input module comprises a first transistor;
the grid electrode of the first transistor is connected with the first node, the first pole of the first transistor is connected with the first reference voltage, and the second pole of the first transistor is connected with the input end of the output module.
3. The fingerprint identification circuit of claim 2, wherein the input module further comprises a first capacitor;
the first capacitor is connected between the gate and the first pole of the first transistor.
4. The fingerprint identification circuit of claim 1, wherein the reset module comprises a second transistor;
the grid electrode of the second transistor is connected with the reset control signal, the first electrode of the second transistor is connected with the second reference voltage, and the second electrode of the second transistor is connected with the first node.
5. The fingerprint identification circuit of claim 1, wherein the control module comprises a third transistor;
the gate of the third transistor is connected to the read control signal, the first pole of the third transistor is connected to the alternating current, and the second pole of the third transistor is connected to the ultrasonic transducer.
6. The fingerprint identification circuit of claim 1, wherein the output module comprises a fourth transistor;
the grid electrode of the fourth transistor is connected with the reading control signal, the first electrode of the fourth transistor is connected with the output end of the input module, and the second electrode of the fourth transistor is connected with the reading signal end.
7. A fingerprint recognition circuit according to any one of claims 2-6, wherein all switching transistors are N-type transistors or P-type transistors.
8. The fingerprint identification circuit of claim 1 wherein said transmit ultrasonic transducer and said receive ultrasonic transducer are co-located; or alternatively, the first and second heat exchangers may be,
the transmit ultrasonic transducer and the receive ultrasonic transducer are stacked.
9. A touch display panel comprising a display panel and a plurality of fingerprint recognition circuits according to any one of claims 1-8.
10. A driving method of a fingerprint recognition circuit according to any one of claims 1 to 8, comprising:
a reset stage, wherein the reset module provides the second reference voltage to the first node under the control of the reset control signal so as to reset the potential of the first node; the input module outputs a signal under the control of the first node;
a reading stage, wherein the control module provides alternating current to the ultrasonic transducer under the control of the reading control signal; the ultrasonic transducer emits ultrasonic waves; when a finger touch is performed, the ultrasonic wave receiving transducer receives ultrasonic waves reflected by the finger and changes the potential of the first node; the input module controls the signal value of the output end of the first node according to the potential of the first node; the output module provides the signal output by the input module to the reading signal end under the control of the reading control signal.
Priority Applications (1)
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| CN110010046A (en) * | 2019-04-22 | 2019-07-12 | 京东方科技集团股份有限公司 | Display panel, its detection method and display device |
| CN110097043A (en) * | 2019-05-05 | 2019-08-06 | 京东方科技集团股份有限公司 | Sensor pixel, ultrasonic sensor, OLED display panel and OLED display |
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| CN108776797A (en) * | 2018-07-03 | 2018-11-09 | 京东方科技集团股份有限公司 | A kind of fingerprint recognition circuit and its driving method, display device |
| CN110010046A (en) * | 2019-04-22 | 2019-07-12 | 京东方科技集团股份有限公司 | Display panel, its detection method and display device |
| CN110097043A (en) * | 2019-05-05 | 2019-08-06 | 京东方科技集团股份有限公司 | Sensor pixel, ultrasonic sensor, OLED display panel and OLED display |
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