CN114120878A - Display panel, driving method thereof and display device - Google Patents
Display panel, driving method thereof and display device Download PDFInfo
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- CN114120878A CN114120878A CN202111445900.3A CN202111445900A CN114120878A CN 114120878 A CN114120878 A CN 114120878A CN 202111445900 A CN202111445900 A CN 202111445900A CN 114120878 A CN114120878 A CN 114120878A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
Abstract
The invention provides a display panel, a driving method thereof and a display device, wherein a first electrode in the display panel is an electrode at one side of an ultrasonic fingerprint sensor under a screen, which is far away from an array layer (equivalent to a TFT substrate), the first electrode is not required to be subjected to blocking processing, a second electrode is an electrode at one side of an adjacent array layer of the ultrasonic fingerprint sensor under the screen, and a plurality of independent second electrodes can be formed simply and with higher precision based on the manufacturing process of the array layer in the array layer, so that the blocking processing of the plurality of second electrodes can meet the precision requirement of a fingerprint sensing pixel unit, and the purpose of applying a driving signal to the second electrode is realized through a transistor in the array layer.
Description
Technical Field
The present invention relates to the field of display panel design technologies, and in particular, to a display panel, a driving method thereof, and a display device.
Background
With the rapid development of science and technology, mobile products with biological recognition function gradually enter people's lives.
The fingerprint is a characteristic which is inherent and unique to the human body and which is distinguishable from others, and is composed of a series of valleys and ridges on the surface of the skin at the finger tip, the composition details of which typically include the branches of the ridges, the ends of the ridges, the arches, the tent-like arches, the left-handed, right-handed, spiral, or double-handed details, which determine the unique characteristics of the fingerprint and therefore are of great interest.
In order to make the display panel have the functions of touch control, fingerprint identification and the like, the component of the ultrasonic fingerprint sensor is one of essential components of the display panel, wherein the ultrasonic fingerprint sensor is arranged below the display panel at present and is also called as an under-screen ultrasonic fingerprint sensor.
Ultrasonic fingerprint sensor can only be used for producing ultrasonic drive signal from the electrode application that deviates from TFT (Thin Film Transistor) base plate one side under the present screen, and the electrode that ultrasonic fingerprint sensor deviates from TFT base plate one side under the screen passes through the printing technology preparation for silver thick liquid electrode usually, if the mode that adopts phased array applys drive signal, need improve the electrode that ultrasonic fingerprint sensor deviates from TFT base plate one side under the screen, form a plurality of independent electrode blocks just can.
However, after the silver paste electrode manufactured by the printing process is subjected to imaging processing, the imaging precision is poor, and a relatively large gap exists between the independent electrode blocks, so that the precision requirement of the fingerprint sensing pixel unit is exceeded.
Disclosure of Invention
In view of the above, to solve the above problems, the present invention provides a display panel, a driving method thereof and a display device, and the technical solution is as follows:
a display panel, the display panel comprising:
a substrate;
a first electrode on the substrate;
the piezoelectric induction layer is positioned on one side, away from the substrate, of the first electrode;
a plurality of independent second electrodes positioned on one side of the piezoelectric sensing layer, which faces away from the first electrode;
the array layer is positioned on one side, away from the piezoelectric induction layer, of the second electrode and comprises a plurality of transistors, and one transistor corresponds to one second electrode;
wherein, in the ultrasonic driving phase, a driving signal is applied to the second electrode through the transistor.
A driving method of a display panel, the driving method being applied to the display panel, the driving method comprising:
in the ultrasonic driving stage, a driving signal is applied to each second electrode area, and the phases of the driving signals applied to any two second electrode areas are different; a fixed voltage signal is applied to the first electrode.
A display device comprises the display panel.
Compared with the prior art, the invention has the following beneficial effects:
the present invention provides a display panel including: a substrate; a first electrode on the substrate; the piezoelectric induction layer is positioned on one side, away from the substrate, of the first electrode; a plurality of independent second electrodes positioned on one side of the piezoelectric sensing layer, which faces away from the first electrode; the array layer is positioned on one side, away from the piezoelectric induction layer, of the second electrode and comprises a plurality of transistors, and one transistor corresponds to one second electrode; wherein, in the ultrasonic driving phase, a driving signal is applied to the second electrode through the transistor.
According to the display panel, the first electrode is an electrode on one side of a screen lower ultrasonic fingerprint sensor deviating from an array layer (equivalent to a TFT substrate), the first electrode does not need to be processed in a blocking mode, the second electrode is an electrode on one side of an array layer adjacent to the screen lower ultrasonic fingerprint sensor, the second electrode is arranged in the array layer based on the manufacturing process of the array layer, a plurality of independent second electrodes can be simply formed with high precision, the blocking processing of the plurality of second electrodes can meet the precision requirement of a fingerprint sensing pixel unit, and the purpose of applying a driving signal to the second electrode is achieved through a transistor in the array layer.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic cross-sectional view of a display panel according to an embodiment of the invention;
FIG. 2 is a schematic cross-sectional view of another display panel according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a finger touching a display panel according to an embodiment of the present invention;
fig. 4 is a schematic layout view of a second electrode according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of applying a driving signal to a second electrode region according to an embodiment of the present invention;
FIG. 6 is a schematic layout view of another second electrode according to an embodiment of the present invention;
FIG. 7 is a schematic layout view of another second electrode according to an embodiment of the present invention;
FIG. 8 is a schematic layout view of another second electrode according to an embodiment of the present invention;
fig. 9 is a schematic layout view of another second electrode according to an embodiment of the present invention;
fig. 10 is a schematic diagram illustrating a relative position relationship between a first electrode and a second electrode according to an embodiment of the present invention;
fig. 11 is a schematic circuit diagram of a control circuit for applying a driving signal to the second electrode according to an embodiment of the present invention;
FIG. 12 is a schematic diagram of a signal waveform according to an embodiment of the present invention;
fig. 13 is a flowchart illustrating a driving method of a display panel according to an embodiment of the invention;
fig. 14 is a schematic structural diagram of a display device 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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Referring to fig. 1, fig. 1 is a schematic cross-sectional view of a display panel according to an embodiment of the present invention.
The display panel includes:
a substrate 11.
A first electrode 12 on the substrate 11.
And the piezoelectric induction layer 13 is positioned on the side, away from the substrate 11, of the first electrode 12.
A plurality of separate second electrodes 14 located on a side of the piezoelectric sensing layer 13 facing away from the first electrode 12.
Further, referring to fig. 2, fig. 2 is a schematic cross-sectional view of another display panel according to an embodiment of the present invention.
The display panel further includes:
an array layer 15 located on a side of the second electrode 14 facing away from the piezoelectric sensing layer 13, wherein the array layer 15 includes a plurality of transistors 16, and one of the transistors 16 corresponds to one of the second electrodes 14.
Wherein, in the ultrasonic driving phase, a driving signal is applied to the second electrode 14 through the transistor 16.
As shown in fig. 2, the transistor 16 includes an active layer 161, a gate 162, a drain 163, and a source 164, where the source 164 serves as one electrode terminal of the transistor 16, and the drain 163 serves as the other electrode terminal of the transistor 16, in the embodiment of the present application, the electrically connecting the drain 163 and the second electrode 14 is taken as an example, and as shown in fig. 2, the electrically connecting the drain 163 and the second electrode 14 is achieved through the through hole 17, but is not limited to this.
In fig. 2, the display panel may further include: a dielectric layer 18 located between the second electrode 14 and the array layer 15, wherein the dielectric layer 18 plays a role of insulation and planarization, and corresponding signal traces and the like can be disposed in the dielectric layer 18, and the first trace L1 for transmitting driving signals is disposed in the dielectric layer 18.
In fig. 2, the display panel may further include: the cover plate 19 is located on one side of the array layer 15, which is away from the substrate 11, and when functions such as fingerprint identification or touch control are performed, the finger fingerprint 20 is in contact with the cover plate 19.
It should be noted that other functional film layers are also included between the cover plate 19 and the array layer 15, which are not shown in fig. 2 and are not limited in the embodiments of the present application.
In this embodiment, the first electrode 12 is an electrode on a side of the under-screen ultrasonic fingerprint sensor facing away from the TFT substrate (corresponding to the array layer 15 in this application), and the whole first electrode 12 is formed by printing, but not limited to, without performing a blocking process on the first electrode 12.
That is to say, in the embodiment of the present application, the first electrode 12 has a full-surface electrode structure, that is, the film layer where the first electrode 12 is located may have a full-surface structure, so that the structure of the display panel is simpler and the manufacturing cost is lower.
The second electrode 14 is an electrode on one side of the under-screen ultrasonic fingerprint sensor adjacent to the TFT substrate and is disposed in the TFT substrate, and based on the manufacturing process of the TFT substrate, a plurality of independent second electrodes 14 can be formed very simply and with high precision, so that the requirement for precision of the fingerprint sensing pixel unit can be met by the blocking processing of the plurality of second electrodes 14.
It should be noted that in the present application, at least one second electrode 14 serves as a fingerprint sensing pixel unit.
In fig. 1, the second electrode layer 14 and the array layer 15 are illustrated as two film layers, and the second electrode layer 14 may be one of the film layers in the array layer 15.
As shown in fig. 2, the array layer 15 includes a plurality of transistors 16, one transistor 16 corresponds to one second electrode 14, the second electrode 14 is electrically connected to one electrode terminal of the transistor 16, and a driving signal for generating an ultrasonic signal is applied to the corresponding second electrode 14 through the other electrode terminal of the transistor 16 by the underscreen fingerprint sensor.
It should be noted that, in the ultrasonic driving stage, the second electrode 14 receives a driving signal for generating an ultrasonic signal by the underscreen fingerprint sensor, and the first electrode 12 is an entire electrode film layer for receiving a fixed voltage signal; at this time, the piezoelectric material in the piezoelectric sensing layer 13 may deform, or the piezoelectric material in the piezoelectric sensing layer 13 may drive the upper and lower film layers to vibrate together, so as to generate ultrasonic waves to be transmitted.
In the ultrasonic receiving stage, a fixed voltage signal is input to the first electrode 12, and after the piezoelectric sensing layer 13 receives the ultrasonic wave, fingerprint identification signals are respectively output through the second electrodes 14.
Referring to fig. 3, fig. 3 is a schematic diagram of a finger touch display panel according to an embodiment of the present invention.
As shown in fig. 3, the valleys 201 and ridges 202 in the finger print 20 reflect the ultrasonic waves generated during the ultrasonic driving phase, because the interface impedance of the valleys 201 and ridges 202 in the finger print 20 is different, the valleys 201 are located as a cavity, the inside is filled with air, the interface where the ridges 202 are located is the skin surface, and the impedance of the air is generally lower than that of other media; therefore, when a finger touches the display panel, the ultrasonic waves generated in the ultrasonic drive stage are reflected at different positions of the valleys 201 and the ridges 202 after being emitted to the finger, and the reflected energy at the positions of the valleys 201 is strong, so that the positions of the valleys 201 and the ridges 202 can be determined by the fingerprint recognition signals output from the respective second electrodes 14.
It should be noted that the concept of the valley 201 and the ridge 202 in the finger fingerprint 20 in the embodiment of the present application is explained with respect to the finger, and in fig. 3, the position of the protrusion in the curve represents the position of the valley 201, and the position of the depression in the curve represents the position of the ridge 202.
Optionally, the piezoelectric sensing layer 13 is made of a piezoelectric material, for example, a material such as polyvinylidene fluoride (PVDF), aluminum nitride, zinc oxide, or lead zirconate titanate (PZT) may be used to manufacture the piezoelectric sensing layer 13 in the embodiment of the present application.
Therefore, in the present application, the plurality of independent second electrodes 14 are formed on one side of the array layer 15 without performing a blocking process on the first electrode 12, and the gaps between the plurality of independent second electrodes 14 can meet the accuracy requirement of the fingerprint sensing pixel unit based on the manufacturing process of the array layer 15, so that when the driving signal is applied in the phased array manner, the driving signal only needs to be applied through the transistor 16 corresponding to the second electrode 14 in the array layer 15.
That is to say, this application can also apply drive signal through the mode that adopts the phased array outside can satisfying the high accuracy demand of fingerprint sensing pixel unit to the intensity of the ultrasonic wave of ultrasonic fingerprint sensor output under the reinforcing ultrasonic drive stage screen, and then improve display panel's fingerprint detection precision.
Optionally, in another embodiment of the present application, referring to fig. 4, fig. 4 is a schematic layout diagram of a second electrode according to an embodiment of the present invention.
The plurality of independent second electrodes 14 are divided into at least two second electrode areas 14A, and at least one second electrode 14 is included in any one of the second electrode areas 14A.
In the ultrasonic driving phase, the driving signal is applied to each of the second electrode regions 14A, and the phases of the driving signals applied to any two of the second electrode regions 14A are different.
In fig. 4, an example in which one second electrode region 14A includes four second electrodes 14 is described.
In this embodiment, two second electrode regions 14A are taken as an example for explanation, in the ultrasonic driving phase, a first driving signal is applied to a first second electrode region 14A, that is, a first driving signal is applied to each second electrode 14 in the first second electrode region 14A; the second electrode region 14A is applied with the second driving signal, that is, each second electrode 14 in the second electrode region 14A is applied with the second driving signal.
The first driving signal and the second driving signal are driving signals for driving the under-screen fingerprint sensor to generate ultrasonic signals.
In order to emit ultrasonic waves with stronger energy, the phases of the first driving signal and the second driving signal are different, so that the ultrasonic waves generated by the first driving signal and the ultrasonic waves generated by the second driving signal can be converged in a certain area in the transmission process to form the ultrasonic waves with stronger energy, the energy of the emitted ultrasonic waves is improved, the energy of the ultrasonic waves after being reflected by fingerprints is also enhanced, and the fingerprint identification capability of the display panel is further improved.
Therefore, the second electrode regions 14A can be reasonably divided according to the fingerprint identification capability required by the display panel, and the number of the second electrodes 14 included in each second electrode region 14A can be reasonably planned.
It should be noted that the number of the second electrodes included in the plurality of second electrode regions 14A may be the same or different, and is not limited in the embodiment of the present application.
It should be noted that, referring to fig. 5, fig. 5 is a schematic diagram of applying a driving signal to the second electrode region according to an embodiment of the present invention. In order to apply the same driving signal to the plurality of second electrodes 14 in each second electrode region 14A, the signal traces of the plurality of second electrodes 14 may be connected together, and the purpose of applying the same driving signal to the plurality of second electrodes 14 is achieved through one signal port, so as to simplify the wiring difficulty of the display panel.
Optionally, in another embodiment of the present application, referring to fig. 6, fig. 6 is a schematic layout diagram of another second electrode provided in the embodiment of the present invention.
A plurality of independent second electrodes 14 are arranged in an array.
In this embodiment, the plurality of second electrodes 14 are arranged in an array, so that the contact position of the finger with the display panel or the position of the valley or ridge in the fingerprint can be more easily determined in the fingerprint identification stage, the operation steps of the fingerprint identification module in the display panel are saved, and the sensitivity of fingerprint identification is improved.
It should be noted that the shape of the second electrode 14 is not limited in the embodiment of the present application, and it may be in other shapes such as a long strip shape or a square block shape, and the number of the second electrodes 14 may be set reasonably according to the requirement of the fingerprint identification accuracy of the display panel.
Optionally, in another embodiment of the present application, referring to fig. 7, fig. 7 is a schematic layout diagram of another second electrode provided in an embodiment of the present invention.
In the row direction of the array arrangement, the distance between two adjacent second electrodes 14 is equal, i.e., D1 ═ D2 ═ D … ═ Dn.
Specifically, as shown in fig. 7, the distance between two adjacent second electrodes 14 is equal in the row direction of the array arrangement, and the distance between two adjacent second electrodes 14 is not limited in the column direction of the array arrangement.
Or the like, or, alternatively,
referring to fig. 8, fig. 8 is a schematic layout view of another second electrode according to an embodiment of the present invention.
In the column direction of the array arrangement, the distance between two adjacent second electrodes 14 is equal, i.e., Q1-Q2- … -Qm.
Specifically, as shown in fig. 8, the distance between two adjacent second electrodes 14 is equal in the column direction of the array arrangement, and the distance between two adjacent second electrodes 14 is not limited in the row direction of the array arrangement.
Or the like, or, alternatively,
referring to fig. 9, fig. 9 is a schematic layout view of another second electrode according to an embodiment of the present invention.
In the row direction of the array arrangement, the distance between two adjacent second electrodes 14 is equal, and in the column direction of the array arrangement, the distance between two adjacent second electrodes 14 is equal, i.e., D1 ═ D2 ═ … ═ Dn, and Q1 ═ Q2 ═ … ═ Qm.
In this embodiment, the plurality of second electrodes 14 are arranged in an array, and further, the distance between two adjacent second electrodes 14 in the row direction and/or the column direction is defined, so that the display panel can more easily determine the contact position of a finger and the display panel or the position of a valley or a ridge in a fingerprint at the fingerprint identification stage, the operation steps of a fingerprint identification module inside the display panel are saved, and the sensitivity of fingerprint identification is improved.
It should be noted that the number of the second electrodes 14, the distance between two adjacent second electrodes 14, and the like can be reasonably set according to the requirement of the fingerprint identification accuracy of the display panel.
Optionally, in another embodiment of the present application, referring to fig. 10, fig. 10 is a schematic diagram of a relative position relationship between a first electrode and a second electrode according to an embodiment of the present invention.
The orthographic projection of the first electrode 12 on the substrate 11 completely covers the orthographic projection of any one of the second electrodes 14 on the substrate 11.
In this embodiment, in the direction perpendicular to the substrate 11, the orthographic projection of the first electrode 12 on the substrate 11 completely covers the orthographic projection of any one of the second electrodes 14 on the substrate 11, so that the signal applied to the piezoelectric sensing layer 13 can be stronger, and the fingerprint identification signal output by the second electrode 14 after the piezoelectric sensing layer 13 receives the reflected ultrasonic signal can be stronger, thereby improving the accuracy and sensitivity of fingerprint detection of the display panel.
Optionally, in another embodiment of the present application, referring to fig. 11, fig. 11 is a schematic circuit structure diagram of a control circuit for applying a driving signal to a second electrode according to an embodiment of the present invention.
The display panel further includes: and the control circuits 100 are in one-to-one correspondence with the second electrodes 14.
The control circuit 100 includes: a first diode D1, a second diode D2, a first transistor M1, a second transistor M2, a third transistor M3 and a capacitor Cp.
An anode of the first diode D1 is connected to a first electrode terminal of the second transistor M2 to form a first connection node a1, the first connection node a1 is electrically connected to a first trace L1, and the first trace L1 is used for transmitting the driving signal DiodeBias.
The second electrode terminal of the second transistor M2 is connected to the gate of the first transistor M1 to form a second connection node a2, and the second connection node a2 is electrically connected to the second electrode 14.
The cathode of the first diode D1 is connected to the first plate of the capacitor Cp to form a third connection node A3, and the third connection node A3 is electrically connected to the second connection node a2 and the second electrode 14, respectively.
The second plate of the capacitor Cp is grounded.
A first electrode terminal of the first transistor M1 is electrically connected to the second electrode terminal of the third transistor M3, and a second electrode terminal of the first transistor M1 is electrically connected to a voltage input terminal Vcc.
A first electrode terminal of the third transistor M3 is electrically connected to a second trace L2, and the second trace L2 is used for transmitting an output signal Dn of the control circuit.
The gate of the second transistor M2 is electrically connected to a third trace L3, and the third trace L3 is used for transmitting a first control signal OverDrive.
The gate of the third transistor M3 is electrically connected to a fourth trace L4, and the fourth trace L4 is used for transmitting a second control signal Rn.
An anode of the second diode D2 is electrically connected to the first trace L1, and a cathode of the second diode D2 is electrically connected to the third trace L3.
In this embodiment, as shown in fig. 11, the display panel further includes: a fifth trace L5, the fifth trace L5 is electrically connected to the first electrode 12, and the fifth trace L5 is used for transmitting the fixed voltage signal VDD applied to the first electrode 12.
Referring to fig. 12, fig. 12 is a schematic signal waveform diagram provided by an embodiment of the invention, in the ultrasonic driving stage, the fixed voltage signal VDD is continuously applied to the first electrode 12 through the fifth wire L5, and the driving signal DiodeBias is applied to the second electrode 14 through the first wire L1.
As shown in fig. 12, the driving signal DiodeBias includes a positive half-cycle driving signal and a negative half-cycle driving signal, and in order to realize the ultrasonic wave with stronger energy, the voltage value of the driving signal DiodeBias is larger, and when the driving signal DiodeBias is the positive half-cycle driving signal, the positive half-cycle driving signal is also applied to one electrode terminal of the second transistor M2; the second transistor M2 may now be broken down.
In order to prevent the second transistor M2 from being broken down, in this application, the second diode D2 is provided, so that the anode of the second diode D2 is electrically connected to the first trace L1, and the cathode of the second diode D2 is electrically connected to the third trace L3, so that the positive half-cycle driving signal is also applied to the gate of the second transistor M2 through the second diode D2, so that the voltage difference between the gate of the second transistor M2 and the electrode is close to zero, and it is ensured that the second transistor M2 is in the off state in the ultrasonic sampling stage and will not be broken down.
Therefore, when the driving signal DiodeBias is a positive half-cycle driving signal, the positive half-cycle driving signal applies the driving signal DiodeBias to the second electrode 14 through the first diode D1 and charges the capacitor Cp, and the voltage of the third node A3 belongs to a stable state in the case of the saturated state of the capacitor Cp.
Moreover, since the positive half-cycle driving signal is transmitted to the gate of the first transistor M1 after passing through the first diode D1, in order to prevent the breakdown of the first transistor M1, in the embodiment of the present application, the voltage input terminal Vcc is in a floating state, so as to ensure that a local circuit of the first transistor M1 is in an open circuit state, so as to protect the first transistor M1, and obviously, the third transistor M3 is also protected when the protection of the first transistor M1 is implemented.
When the driving signal DiodeBias is a negative half-cycle driving signal, the second transistor M2 can be turned on by the first control signal OverDrive, and the negative half-cycle driving signal applies the driving signal DiodeBias to the second electrode 14 through the second transistor M2 and charges the capacitor Cp, and the voltage of the third node A3 belongs to a stable state when the capacitor Cp is in a saturated state.
Based on this, in the ultrasonic driving stage, the driving signal diode bias is applied to the second electrode 14 through the first diode D1 or the second transistor M2, and the first electrode 12 continuously receives the fixed voltage signal VDD through the fifth wire L5, so that a voltage difference is formed between the piezoelectric sensing layers 13, the piezoelectric material in the piezoelectric sensing layers 13 is deformed, or the piezoelectric material in the piezoelectric sensing layers 13 drives the upper and lower film layers to vibrate together, thereby generating ultrasonic waves to transmit the ultrasonic waves.
In the ultrasonic sampling phase, that is, in the ultrasonic receiving phase, the fixed voltage signal VDD is continuously applied to the first electrode 12 through the fifth trace L5, and after the piezoelectric sensing layer 13 receives the ultrasonic wave, fingerprint identification signals are respectively output through the second electrodes 14, where the fingerprint identification signals are signals represented by the voltage.
The fingerprint identification signal is applied to the gate of the first transistor M1 in combination with a stable voltage signal from the third node a3, and another voltage signal is applied through the first trace L1 and is also applied to the gate of the first transistor M1 through the first diode D1 to ensure that the first transistor M1 is completely in a conducting state, at which the voltage input terminal Vcc is not in a floating state, and the first transistor M1 is in a conducting state by a voltage signal input at the control voltage input terminal Vcc, at which the first transistor M1 converts the received voltage signal into a current signal I to be output.
In the ultrasonic reading stage, the third transistor M3 is in a conducting state, and the output signal Dn of the control circuit 100 is transmitted through the second wire L2 to be processed by the back-end circuit of the control circuit 100.
Optionally, in another embodiment of the present application, since the voltage of the driving signal diode bias transmitted by the first trace L1 is higher, in order to prevent a higher capacitive load from existing between the first trace L1, the third trace L3, and the fourth trace L4, the first trace L1, the third trace L3, and the fourth trace L4 are disposed in different layers and separated by more film layers as much as possible, so as to reduce the capacitive load between the traces to the greatest extent and reduce the risk of the trace insulating layer being broken down.
Optionally, in another embodiment of the present application, in order to apply the same driving signal to the plurality of second electrodes 14 in each second electrode region 14A, the first traces L1 of the plurality of second electrodes 14 may be connected together, and the purpose of applying the same driving signal to the plurality of second electrodes 14 is achieved through one signal port, so as to simplify the wiring difficulty of the display panel.
Optionally, based on all the above embodiments of the present application, in another embodiment of the present application, a driving method of a display panel is further provided, where the driving method is applied to the display panel described in the above embodiments of the present application, and referring to fig. 13, fig. 13 is a schematic flow chart of the driving method of the display panel provided in the embodiment of the present invention.
The driving method includes:
s101: in the ultrasonic driving stage, a driving signal is applied to each second electrode area, and the phases of the driving signals applied to any two second electrode areas are different; a fixed voltage signal is applied to the first electrode.
In the embodiment, in the ultrasonic driving stage, the second electrode receives a driving signal used for generating an ultrasonic signal by the finger print sensor under the screen, and the first electrode is a whole-surface electrode film layer used for receiving a fixed voltage signal; at this moment, the piezoelectric material in the piezoelectric sensing layer can deform, or the piezoelectric material in the piezoelectric sensing layer can drive the upper film layer and the lower film layer to vibrate together, so that ultrasonic waves are generated and transmitted out.
In the ultrasonic receiving stage, a fixed voltage signal is input to the first electrode, and after the piezoelectric induction layer receives the ultrasonic wave, fingerprint identification signals are respectively output through the second electrodes.
Taking two second electrode regions as an example for explanation, in the ultrasonic driving stage, a first driving signal is applied to a first second electrode region, that is, a first driving signal is applied to each second electrode in the first second electrode region; the second electrode region is applied with the second driving signal, that is, each second electrode in the second electrode region is applied with the second driving signal.
The first driving signal and the second driving signal are driving signals for driving the under-screen fingerprint sensor to generate ultrasonic signals.
In order to emit ultrasonic waves with stronger energy, the phases of the first driving signal and the second driving signal are different, so that the ultrasonic waves generated by the first driving signal and the ultrasonic waves generated by the second driving signal can be converged in a certain area in the transmission process to form the ultrasonic waves with stronger energy, the energy of the emitted ultrasonic waves is improved, the energy of the ultrasonic waves after being reflected by fingerprints is also enhanced, and the fingerprint identification capability of the display panel is further improved.
Therefore, the second electrode regions can be reasonably divided according to the fingerprint identification capability required by the display panel, and the number of the second electrodes included in each second electrode region can be reasonably planned.
It should be noted that the number of the second electrodes included in the plurality of second electrode regions may be the same or different, and is not limited in the embodiment of the present application.
It should be noted that, in order to apply the same driving signal to the plurality of second electrodes in each second electrode region, signal traces of the plurality of second electrodes may be connected together, and the purpose of applying the same driving signal to the plurality of second electrodes is achieved through one signal port, so as to simplify the wiring difficulty of the display panel.
Optionally, based on the above embodiments of the present application, a display device is further provided in another embodiment of the present application, and referring to fig. 14, fig. 14 is a schematic structural diagram of the display device provided in the embodiments of the present invention.
The display device 200 includes the display panel according to the above embodiments of the present application.
The display device 200 includes, but is not limited to, a display device such as a mobile phone or a flat panel, and the display device has at least the same technical effects as the display panel.
The display panel, the driving method thereof and the display device provided by the present invention are described in detail above, and the principle and the embodiment of the present invention are explained in detail herein by applying specific examples, and the description of the above embodiments is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include or include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (14)
1. A display panel, comprising:
a substrate;
a first electrode on the substrate;
the piezoelectric induction layer is positioned on one side, away from the substrate, of the first electrode;
a plurality of independent second electrodes positioned on one side of the piezoelectric sensing layer, which faces away from the first electrode;
the array layer is positioned on one side, away from the piezoelectric induction layer, of the second electrode and comprises a plurality of transistors, and one transistor corresponds to one second electrode;
wherein, in the ultrasonic driving phase, a driving signal is applied to the second electrode through the transistor.
2. The display panel of claim 1, wherein the plurality of independent second electrodes are divided into at least two second electrode regions, any one of the second electrode regions including at least one of the second electrodes therein;
in the ultrasonic driving stage, the driving signal is applied to each second electrode region, and the phases of the driving signals applied to any two second electrode regions are different.
3. The display panel of claim 1, wherein a plurality of independent second electrodes are arranged in an array.
4. The display panel according to claim 3,
in the row direction of the array arrangement, the intervals between two adjacent second electrodes are equal;
and/or the presence of a gas in the gas,
in the column direction of the array arrangement, the intervals between two adjacent second electrodes are equal.
5. The display panel according to claim 1, wherein an orthogonal projection of the first electrode on the substrate completely covers an orthogonal projection of any one of the second electrodes on the substrate.
6. The display panel according to claim 1, characterized in that the display panel further comprises: the control circuits correspond to the second electrodes one by one;
the control circuit includes: the circuit comprises a first diode, a second diode, a first transistor, a second transistor, a third transistor and a capacitor;
the anode of the first diode is connected with the first electrode end of the second transistor to form a first connection node, the first connection node is electrically connected with a first wire, and the first wire is used for transmitting the driving signal;
a second electrode end of the second transistor is connected with a grid electrode of the first transistor to form a second connection node, and the second connection node is electrically connected with the second electrode;
the cathode of the first diode is connected with the first pole plate of the capacitor to form a third connection node, and the third connection node is electrically connected with the second connection node and the second electrode respectively;
the second plate of the capacitor is grounded;
a first electrode end of the first transistor is electrically connected with a second electrode end of the third transistor, and a second electrode end of the first transistor is electrically connected with a voltage input end;
a first electrode end of the third transistor is electrically connected with a second wire, and the second wire is used for transmitting an output signal of the control circuit;
the grid electrode of the second transistor is electrically connected with a third wire, and the third wire is used for transmitting a first control signal;
the grid electrode of the third transistor is electrically connected with a fourth wire, and the fourth wire is used for transmitting a second control signal;
the anode of the second diode is electrically connected with the first wire, and the cathode of the second diode is electrically connected with the third wire.
7. The display panel according to claim 6, wherein the first trace, the third trace and the fourth trace are disposed in different layers.
8. The display panel according to claim 6, characterized in that the display panel further comprises:
a fifth wire electrically connected to the first electrode.
9. The display panel of claim 6, wherein the first traces corresponding to the second electrodes in the same second electrode region are connected together for receiving the same driving signal.
10. The display panel according to claim 6, wherein when the driving signal is a forward driving signal, the forward driving signal is transmitted to the second electrode through the first trace and the first diode;
when the driving signal is a negative driving signal, the negative driving signal is transmitted to the second electrode through the second transistor.
11. The display panel according to claim 6, wherein the voltage input terminal is in a floating state during the ultrasonic driving phase.
12. The display panel of claim 1, wherein the first electrode is a full-area electrode structure.
13. A driving method of a display panel, the driving method being applied to the display panel according to any one of claims 1 to 12, the driving method comprising:
in the ultrasonic driving stage, a driving signal is applied to each second electrode area, and the phases of the driving signals applied to any two second electrode areas are different; a fixed voltage signal is applied to the first electrode.
14. A display device characterized in that it comprises a display panel according to any one of claims 1 to 12.
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