WO2021159392A1

WO2021159392A1 - Fingerprint recognition module and drive method therefor, and display apparatus

Info

Publication number: WO2021159392A1
Application number: PCT/CN2020/075091
Authority: WO
Inventors: 刘英明; 王海生; 丁小梁; 王鹏鹏; 李秀锋; 郭玉珍; 张晨阳; 李佩笑
Original assignee: 京东方科技集团股份有限公司
Priority date: 2020-02-13
Filing date: 2020-02-13
Publication date: 2021-08-19
Also published as: CN113544694A

Abstract

Provided are a fingerprint recognition module and a drive method therefor, and a display apparatus. The fingerprint recognition module comprises: a piezoelectric layer, a sensing electrode layer and a drive electrode layer, wherein the sensing electrode layer is located on one side of the piezoelectric layer. The drive electrode layer comprises: a first drive electrode layer and a second drive electrode layer, wherein the first drive electrode layer is located on the side of the piezoelectric layer that is close to the sensing electrode layer, and the second drive electrode layer is located on the side of the piezoelectric layer that is away from the sensing electrode layer. The first drive electrode layer comprises: a plurality of first drive electrodes arranged in a first direction, and the second drive electrode layer comprises: a plurality of second drive electrodes arranged in a second direction. The first drive electrodes extend in the second direction, and the second drive electrodes extend in the first direction, wherein the first direction is perpendicular to the second direction.

Description

Fingerprint identification module and its driving method and display device

Technical field

The present disclosure relates to, but is not limited to, the field of fingerprint identification, and relates to a fingerprint identification module, a driving method thereof, and a display device.

Background technique

Biometric recognition is a technology used to distinguish different biological characteristics, including recognition technologies such as fingerprints, palm prints, human faces, or irises. Fingerprints are inherently unique and invariant features of the human body that can be distinguished from others. It consists of ridges and valleys on the surface of the fingertips. Because of its uniqueness and immutability, fingerprints can be used for personal identification. Therefore, fingerprint recognition technology has attracted much attention.

Generally, fingerprint identification technology can be divided into optical fingerprint identification technology, silicon chip fingerprint identification technology and ultrasonic fingerprint identification technology. Ultrasonic fingerprint recognition technology has become a popular research direction for major manufacturers due to its safety and low cost.

Ultrasonic fingerprint recognition technology emits ultrasonic waves at the same time in the process of fingerprint recognition, so that the signal-to-noise ratio of the fingerprint signal obtained is low, thereby reducing the accuracy of fingerprint recognition.

Summary of the invention

The following is an overview of the subject matter described in detail in the present disclosure. This summary is not intended to limit the scope of protection of the claims.

In a first aspect, the present disclosure provides a fingerprint recognition module, including: a piezoelectric layer, a sensing electrode layer, and a driving electrode layer; wherein the sensing electrode layer is located on one side of the piezoelectric layer; the driving electrode The layers include: a first driving electrode layer and a second driving electrode layer, wherein the first driving electrode layer is located on the side of the piezoelectric layer close to the sensing electrode layer, and the second driving electrode layer is located on the A side of the piezoelectric layer away from the sensing electrode layer;

The first driving electrode layer includes: a plurality of first driving electrodes arranged in a first direction, and the second driving electrode layer includes: a plurality of second driving electrodes arranged in a second direction; the first driving electrodes Extending in the second direction, the second driving electrode extends in the first direction, and the first direction is perpendicular to the second direction.

In some possible implementations, the orthographic projection of each first driving electrode on the piezoelectric layer and the orthographic projection of each second driving electrode on the piezoelectric layer at least partially overlap.

In some possible implementations, the sensing electrode layer includes: a plurality of sensing electrodes arranged in a matrix, and the sensing electrodes are block electrodes; The orthographic projection of the sensing electrode layer on the piezoelectric layer.

In some possible implementations, the first driving electrode layer and the sensing electrode layer are provided in the same layer; the orthographic projection of the first driving electrode layer on the piezoelectric layer and the sensing electrode layer on the piezoelectric layer There is no overlap area in the orthographic projection between the layers.

In some possible implementations, the fingerprint recognition module further includes: a first insulating layer; the first insulating layer is located on a side of the sensing electrode layer away from the piezoelectric layer, and the first driving electrode The layer is located on a side of the first insulating layer away from the sensing electrode layer.

In some possible implementations, the orthographic projection of the first driving electrode layer on the piezoelectric layer and the orthographic projection of the sensing electrode layer on the piezoelectric layer at least partially overlap.

In some possible implementation manners, the first driving electrode and the second driving electrode are strip-shaped electrodes.

In some possible implementation manners, the first driving electrode and the second driving electrode are metal electrodes.

In some possible implementations, the sensing electrode is a transparent electrode.

In some possible implementation manners, the piezoelectric layer is made of materials including polyvinylidene fluoride, aluminum nitride, polyvinylidene fluoride, or lead zirconate titanate-based perovskite structure composite oxide.

In some possible implementations, the fingerprint recognition module further includes: a substrate; the substrate is located on a side of the first driving electrode layer away from the piezoelectric layer, and is set as a contact surface with the fingerprint to be measured ; Wherein, the thickness of the substrate is 5 micrometers to 30 micrometers.

In some possible implementations, the fingerprint recognition module further includes: a second insulating layer and a reflective layer; the second insulating layer is located on a side of the second driving electrode layer away from the piezoelectric layer; The layer is located on a side of the second insulating layer away from the piezoelectric layer, and is configured to reflect ultrasonic waves.

In some possible implementation manners, the reflective layer is made of: silver.

In some possible implementations, the fingerprint recognition module further includes: a protective layer; the protective layer is located on a side of the reflective layer away from the second insulating layer, and is arranged to isolate water and oxygen to protect the The reflective layer and the protective layer are made of: epoxy resin.

In a second aspect, the present disclosure also provides a display device, including: a display panel and the aforementioned fingerprint identification module.

In some possible implementations, the fingerprint identification module is located on one side of the display panel.

In a third aspect, the present disclosure also provides a method for driving the fingerprint identification module, which is used to drive the above fingerprint identification module, and the method includes:

Provide a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves;

The fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be tested is read from the sensing electrode layer, so as to perform fingerprint identification according to the fingerprint signal.

In some possible implementation manners, the providing a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves includes:

In the first time period, providing a driving signal to the first driving electrode layer, and providing a fixed signal to the second driving electrode layer and the sensing electrode layer to drive the piezoelectric layer to generate ultrasonic waves;

In the second time period, providing a driving signal to the second driving electrode layer, and providing a fixed signal to the first driving electrode layer and the sensing electrode layer to drive the piezoelectric layer to generate ultrasonic waves;

Wherein, the first time period is earlier than or the second time period is later.

In some possible implementation manners, the first driving electrode layer includes: a plurality of first driving electrodes, and the second driving electrode layer includes: a plurality of second driving electrodes;

The providing a driving signal to the first driving electrode layer includes:

Time-sharing providing drive signals to at least two of the first drive electrodes to generate ultrasonic waves with the drive piezoelectric layer;

The providing a driving signal to the second driving electrode layer includes:

A driving signal is provided to at least two of the second driving electrodes in a time sharing manner, and ultrasonic waves are generated by the driving piezoelectric layer.

In some possible implementation manners, the reading from the sensing electrode layer the fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be measured includes:

A fixed signal is provided to the first driving electrode layer and the second driving electrode layer, and the fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be measured is read from the sensing electrode layer.

After reading and understanding the drawings and detailed description, other aspects can be understood.

Description of the drawings

The accompanying drawings are used to provide an understanding of the technical solution of the present disclosure, and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present disclosure, and do not constitute a limitation to the technical solution of the present disclosure.

Figure 1A is a schematic diagram of a fingerprint recognition module emitting ultrasonic waves;

Figure 1B is a schematic diagram of a fingerprint recognition module receiving ultrasonic waves;

2 is a top view of a fingerprint identification module provided by an embodiment of the disclosure;

Figure 3A is a cross-sectional view of Figure 2 along the A-A direction;

Figure 3B is a cross-sectional view of Figure 2 along the B-B direction;

FIG. 4 is a schematic diagram of a fingerprint recognition module in an exemplary embodiment to achieve ultrasonic focusing;

FIG. 5 is a schematic diagram of a fingerprint recognition module in another exemplary embodiment to achieve ultrasonic focusing;

FIG. 6A is a schematic diagram of the ultrasonic wave emitted by the fingerprint identification module provided by an exemplary embodiment focusing on the valley of the fingerprint to be tested; FIG.

6B is a schematic diagram of the ultrasonic wave emitted by the fingerprint identification module provided by an exemplary embodiment focusing on the ridge of the fingerprint to be tested;

FIG. 7 is a top view of a fingerprint identification module provided by an exemplary embodiment;

Figure 8A is a cross-sectional view along the A-A direction of Figure 7;

Figure 8B is a cross-sectional view of Figure 7 along the B-B direction;

FIG. 9 is a schematic structural diagram of a fingerprint identification module provided by an exemplary embodiment;

FIG. 10 is a schematic structural diagram of a display device provided by an embodiment of the disclosure;

FIG. 11 is a flowchart of a method for driving a fingerprint identification module according to an embodiment of the disclosure.

Detailed ways

Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the case of no conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other arbitrarily.

The present disclosure describes a number of embodiments, but the description is exemplary rather than restrictive, and for those of ordinary skill in the art, there may be more within the scope of the embodiments described in the present disclosure. Examples and implementation schemes. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment can be used in combination with any other feature or element in any other embodiment, or can replace any other feature or element in any other embodiment.

The present disclosure includes and contemplates combinations with features and elements known to those of ordinary skill in the art. The embodiments, features, and elements already disclosed in the present disclosure can also be combined with any conventional features or elements to form the technical solution defined by the claims. Any feature or element of any embodiment can also be combined with features or elements from other technologies to form another technical solution defined by the claims. Therefore, it should be understood that any feature shown or discussed in this disclosure can be implemented individually or in any appropriate combination. Therefore, the embodiments are not subject to other restrictions except for the restrictions made according to the appended claims and their equivalents. In addition, various modifications and changes can be made within the protection scope of the appended claims.

Unless otherwise defined, the technical or scientific terms disclosed in the present disclosure shall have the usual meanings understood by those with ordinary skills in the field to which this disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity, or importance, but are only used to distinguish different components. "Include" or "include" and other similar words mean that the element or item appearing before the word encompasses the element or item listed after the word and its equivalents, but does not exclude other elements or items. Similar words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "Down", "Left", "Right", etc. are only used to indicate the relative position relationship. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

FIG. 1A is a schematic diagram of a fingerprint recognition module emitting ultrasonic waves. As shown in Fig. 1A, the fingerprint recognition module includes: an upper electrode 11, a lower electrode 12, and a piezoelectric layer 13 located between the upper electrode 11 and the lower electrode 12. The piezoelectric layer 13 is made of piezoelectric material, which can be excited by an alternating voltage to produce an inverse piezoelectric effect. As shown in Figure 1, when an alternating voltage is input to the upper electrode 11 and the lower electrode 12, the piezoelectric layer 13 is deformed due to the inverse piezoelectric effect, which drives the film layers above and below the piezoelectric layer 13 to vibrate together, thereby Generate ultrasonic waves and radiate outwards.

FIG. 1B is a schematic diagram of a fingerprint recognition module receiving ultrasonic waves. As shown in FIG. 1B, the ultrasonic waves emitted by the fingerprint recognition module are reflected by the fingerprint 500 to be tested, and the reflected ultrasonic waves are converted into alternating voltages in the piezoelectric layer 13. In this case, the upper electrode 11 is grounded, and the lower electrode 12 can be used as a receiving electrode to receive the alternating voltage generated by the piezoelectric layer 13. Since the fingerprint 500 to be tested includes the valley 510 and the ridge 520, their ability to reflect ultrasonic waves is different, resulting in different intensities of the ultrasonic waves reflected by the valley 510 and the ridge 520. Therefore, the position information of the valleys and ridges of the fingerprint to be tested can be obtained by the alternating voltage received by the receiving electrode, so that fingerprint identification can be realized.

2 is a top view of a fingerprint recognition module provided by an embodiment of the disclosure, FIG. 3A is a cross-sectional view of FIG. 2 along the A-A direction, and FIG. 3B is a cross-sectional view of FIG. 2 along the B-B direction. As shown in FIGS. 2 and 3, the fingerprint identification module provided by the embodiment of the present disclosure is used to identify the fingerprint to be tested. The fingerprint identification module includes a piezoelectric layer 10, a sensing electrode layer 20 and a driving electrode layer 30.

The sensing electrode layer 20 is located on one side of the piezoelectric layer 10. The driving electrode layer 30 includes: a first driving electrode layer 31 and a second driving electrode layer 32; the first driving electrode layer 31 is located on the side of the piezoelectric layer 10 close to the sensing electrode layer 20, and the second driving electrode layer 32 is located on the piezoelectric layer 10 is away from the side of the sensing electrode layer 20.

The first driving electrode layer 31 includes: a plurality of first driving electrodes TX_X1 to TX_XM arranged in a first direction D1, and the second driving electrode layer 32 includes: a plurality of second driving electrodes TX_Y1 to TX_YN arranged in a second direction D2; The first driving electrode extends in the second direction, the second driving electrode extends in the first direction, and the first direction D1 is perpendicular to the second direction D2.

The plurality of first driving electrodes TX_X1 to TX_XM are arranged in the same layer, and the plurality of second driving electrodes TX_Y1 to TX_YN are arranged in the same layer.

The extension direction of the first drive electrode is the same as the arrangement direction of the plurality of second drive electrodes, and the extension direction of the second drive electrode is the same as the arrangement direction of the plurality of first drive electrodes, that is, the extension direction of the first drive electrode is perpendicular to the second drive electrode. The direction in which the drive electrode extends.

Each first driving electrode in the first driving electrode layer can be individually controlled. For example, a driving signal can be provided to the first driving electrode by time sharing to achieve focusing of the ultrasound, that is, to enhance the intensity or energy of the ultrasound. Each second driving electrode in the second driving electrode layer can be individually controlled, for example, a driving signal can be provided to the second driving electrode by time sharing to achieve focusing of ultrasound. Since the arrangement direction of the plurality of first driving electrodes is different from the arrangement direction of the plurality of second driving electrodes, the fingerprint recognition module can realize the focusing of ultrasonic waves in two dimensions.

In an exemplary embodiment, the piezoelectric layer may be a planar structure, or may include: piezoelectric structures arranged in an array.

The first driving electrode layer, the second driving electrode layer, and the piezoelectric layer, or the second driving electrode layer, the sensing electrode layer, and the piezoelectric layer may constitute an ultrasonic emitting component. The sensing electrode layer, the second driving electrode layer and the piezoelectric material layer can constitute an ultrasonic receiving component.

When the fingerprint recognition module emits ultrasonic waves, the sensing electrode layer can be grounded to provide driving signals to the first driving electrode layer and the second driving electrode layer respectively. The piezoelectric layer 10 will deform due to the inverse piezoelectric effect, thereby generating ultrasonic waves. And launch outwards. When the fingerprint recognition module receives ultrasonic waves, the driving electrode layer can be grounded, and the fingerprint signal converted by the piezoelectric layer according to the received and reflected ultrasonic signal is read from the sensing electrode layer, thereby realizing fingerprint recognition.

In an exemplary embodiment, when the fingerprint recognition module emits ultrasonic waves, a driving signal is provided to the first driving electrode layer in the first time period, and a driving signal is provided to the second driving electrode layer in the second time period. The cut-off time of the first time period is earlier than the start time of the second time period, or the start time of the first time period is later than the cut-off time of the second time period.

When providing a driving signal to the first driving electrode layer, at least two first driving electrodes may be used as a group of driving electrode groups. For example, the first first driving electrode TX_X1, the second first driving electrode TX_X2, and the third first driving electrode TX_X3 are used as the first group of driving electrode groups, and the second first driving electrode TX_X2, the third first driving electrode TX_X2, and the third first driving electrode TX_X3 One driving electrode TX_X3 and the fourth first driving electrode TX_X4 serve as the second group of driving electrode groups, and so on.

FIG. 4 is a schematic diagram of a fingerprint identification module in an exemplary embodiment to achieve ultrasonic focusing, and FIG. 5 is a schematic diagram of a fingerprint identification module in another exemplary embodiment to achieve ultrasonic focusing. In an exemplary embodiment, when the driving signal is provided to the first driving electrode layer, the driving signal may be provided to each group of driving electrode groups in turn, or driving signals may be provided to multiple groups of driving electrode groups at the same time. For example, it is possible to provide driving signals to the first group of driving electrode groups and the last group of driving electrode groups. FIG. 4 is an example of providing driving signals to each group of driving electrode groups in sequence, and FIG. 5 is an example of providing driving signals to the first group of driving electrode groups and the last group of driving electrode groups. When driving signals are provided to multiple driving electrode groups at the same time, the fingerprint recognition time can be reduced.

When providing a driving signal to the driving electrode group, the driving signal may be provided to at least two first driving electrodes in the driving electrode group in a time-sharing manner. Taking the driving signal provided to the first driving electrode group as an example, the driving signal is provided to the first first driving electrode TX_X1 and the third first driving electrode TX_X3 at the first time point, and the driving signal is provided to the second driving electrode group at the second time point. The first driving electrode TX_X2 provides a driving signal, and the second time point is later than the first time point. In this way, the focus of the ultrasound can be achieved in the fingerprint area directly above the second first driving electrode TX_X2, that is, the intensity or energy of the ultrasound can be enhanced. 4 and 5 are described by taking the example of providing a driving signal to the first driving electrode layer.

When driving signals are provided to the second driving electrode layer, at least two second driving electrodes can be used as a group of driving electrode groups, for example, the first second driving electrode TX_Y1, the second second driving electrode TX_Y2, and the third Two second drive electrodes TX_Y3 are used as the first drive electrode group, and the second second drive electrode TX_Y2, the third second drive electrode TX_Y3, and the fourth second drive electrode TX_Y4 are used as the second drive electrode group, in turn analogy.

In an exemplary embodiment, similar to providing the driving signal to the first driving electrode layer, when the driving signal is provided to the second driving electrode layer, the driving signal may be provided to each group of driving electrode groups in turn, or to multiple groups at the same time. The driving electrode group provides driving signals. For example, driving signals may be provided to the first group of driving electrode groups and the last group of driving electrode groups.

In an exemplary embodiment, when the driving signal is provided to the second driving electrode layer, the driving signal may be sequentially provided to the driving electrode group. When the driving signal is provided to the driving electrode group, the driving signal may be provided to the second driving electrode in a time-sharing manner. Taking the driving signal provided to the first driving electrode group as an example, the driving signal is provided to the first second driving electrode TX_Y1 and the third second driving electrode TX_Y3 at the first time point, and the driving signal is provided to the second driving electrode group at the second time point. The second driving electrode TX_Y2 provides a driving signal, and the second time point is later than the first time point. In this way, the ultrasound can be focused in the fingerprint area corresponding to the second second driving electrode TX_Y2, that is, the intensity or energy of the ultrasound can be enhanced.

6A is a schematic diagram of the ultrasonic wave emitted by the fingerprint identification module provided by an exemplary embodiment being focused to the valley of the fingerprint to be tested, and FIG. 6B is a schematic diagram of the ultrasonic wave emitted by the fingerprint identification module provided by an exemplary embodiment being focused to the valley of the fingerprint to be measured Schematic diagram of the ridge of a fingerprint. As shown in FIG. 6A, the fingerprint to be tested is located on the contact surface 1 of the fingerprint recognition module. When the ultrasonic wave emitted by the fingerprint recognition module is focused on the valley 510 of the fingerprint 500 to be tested, the energy or intensity of the ultrasonic wave reflected by the valley 510 is greater. Big. As shown in FIG. 6B, when the ultrasonic wave emitted by the fingerprint recognition module is focused on the ridge 520 of the fingerprint 500 to be tested, the energy or intensity of the ultrasonic wave reflected by the ridge 520 is smaller. Therefore, the difference between the intensity and energy of the ultrasonic waves reflected by the valley 510 and the ridge 520 of the fingerprint 500 to be tested is also greater, which can help improve fingerprint recognition performance. In addition, as shown in FIGS. 6A and 6B, the ultrasonic waves emitted by the fingerprint recognition module have good directivity, which can reduce the crosstalk between the valleys and ridges of the fingerprint to be tested, and can improve the fingerprint recognition performance.

The fingerprint recognition module provided by the embodiments of the present disclosure includes: a piezoelectric layer, a sensing electrode layer, and a driving electrode layer; the sensing electrode layer is located on one side of the piezoelectric layer; the driving electrode layer includes: a first driving electrode layer and a second driving electrode The first drive electrode layer is located on the side of the piezoelectric layer close to the sensing electrode layer, and the second drive electrode layer is located on the side of the piezoelectric layer away from the sensing electrode layer; the first drive electrode layer includes: A first driving electrode, and the second driving electrode layer includes: a plurality of second driving electrodes arranged in a second direction; the first driving electrodes extend in the second direction, and the second driving electrodes extend in the first direction. The technical solution provided by the present disclosure includes a first driving electrode layer and a second driving electrode layer arranged in different layers, and each driving electrode layer includes: a plurality of driving electrodes, and ultrasonic waves can be achieved by driving the plurality of driving electrodes separately. Two-dimensional focusing, on the one hand, can increase the intensity or energy of the emitted ultrasound; on the other hand, it can make the emitted ultrasound have better directivity, reduce the crosstalk between the valleys and ridges of the fingerprint, and increase the amount of fingerprint signal obtained. The signal-to-noise ratio improves the accuracy of fingerprint recognition.

In an exemplary embodiment, when the fingerprint recognition module realizes the focus of the ultrasonic wave to increase the intensity or energy of the emitted ultrasonic wave, the fingerprint recognition module can not only realize the fingerprint recognition, but also can penetrate the finger to distinguish whether the fingerprint is Real skin.

In an exemplary embodiment, for each first driving electrode, the orthographic projection of the first driving electrode on the piezoelectric layer and the orthographic projection of each second driving electrode on the piezoelectric layer at least partially overlap, that is, the orthographic projection of each second driving electrode on the piezoelectric layer at least partially overlaps. The orthographic projection of a driving electrode on the piezoelectric layer 10 at least partially overlaps the orthographic projection of each second driving electrode on the piezoelectric layer 10, and the orthographic projection of each second driving electrode on the piezoelectric layer 10 overlaps with each first driving electrode. The orthographic projections of the electrodes on the piezoelectric layer 10 at least partially overlap.

In an exemplary embodiment, as shown in FIG. 2, in the fingerprint recognition module provided by an exemplary embodiment, the sensing electrode layer 20 includes a plurality of sensing electrodes arranged in a matrix, which are respectively RX11 to RXMN, The sensing electrodes are block electrodes, where M is the number of sensing electrodes arranged along the first direction, and N is the number of sensing electrodes arranged along the second direction.

In an exemplary embodiment, when the fingerprint recognition module is applied to a display device, the area of the sensing electrode may be equal to the area of the pixel unit in the display device, the number of sensing electrodes may be equal to the number of pixel units, or the sensing electrode The area of the electrode may be larger than the area of the pixel unit, and the number of sensing electrodes may be smaller than the number of pixel units. The number and area of the sensing electrodes can be determined according to the fingerprint recognition accuracy.

In an exemplary embodiment, the number of first driving electrodes may be equal to or not equal to M, and the number of second driving electrodes may be equal to or not equal to N. M, N, the number of first driving electrodes, and the number of second driving electrodes can be determined according to fingerprint recognition accuracy.

The orthographic projection of the second driving electrode layer on the piezoelectric layer covers the orthographic projection of the sensing electrode layer on the piezoelectric layer.

In an exemplary embodiment, when the fingerprint recognition module receives ultrasonic waves, it may be read sequentially along the first direction, or may be read at intervals along the first direction.

In an exemplary embodiment, as shown in FIGS. 2 and 3, the first driving electrode layer 31 and the sensing electrode layer 20 are arranged in the same layer, and the orthographic projection of the first driving electrode layer 31 on the piezoelectric layer and the sensing electrode layer 20 There is no overlap area in the orthographic projection between the piezoelectric layers.

FIG. 7 is a top view of a fingerprint identification module provided by an exemplary embodiment, FIG. 8A is a cross-sectional view of FIG. 7 along the A-A direction, and FIG. 8B is a cross-sectional view of FIG. 7 along the B-B direction. As shown in FIGS. 7 and 8, an exemplary provided fingerprint identification module further includes: a first insulating layer 40.

The first insulating layer 40 is located on the side of the sensing electrode layer 20 away from the piezoelectric layer 10, and the first driving electrode layer 31 is located on the side of the first insulating layer 40 away from the sensing electrode layer 20.

In an exemplary embodiment, the orthographic projection of each first driving electrode on the piezoelectric layer may at least partially overlap with the orthographic projection of the sensing electrode on the piezoelectric layer, or the first driving electrode TX_Xi is on the piezoelectric layer. There may be no overlap area between the orthographic projection on the piezoelectric layer and the orthographic projection of the plurality of sensing electrodes RXi1 to RXiN arranged along the second direction on the piezoelectric layer. 7 and 8 are illustrated by taking as an example the orthographic projection of each first driving electrode on the piezoelectric layer and the orthographic projection of the sensing electrode on the piezoelectric layer at least partially overlap.

In an exemplary embodiment, the disposition of the sensing electrode layer and the first driving electrode layer in different layers can increase the area of each sensing electrode or the size of the sensing electrode in the sensing electrode layer under the same area of the fingerprint recognition module. Quantity to improve the fingerprint recognition accuracy of the fingerprint recognition module.

In an exemplary embodiment, the material of the first insulating layer 40 may be silicon oxide, silicon nitride, or a composite of silicon oxide and silicon nitride.

In an exemplary embodiment, the first driving electrode and the second driving electrode may be strip-shaped electrodes.

In an exemplary embodiment, the first driving electrode and the second driving electrode may be metal electrodes, or may be transparent electrodes. Wherein, the material of the metal electrode can be one or more of silver, platinum, iridium, gold, aluminum, copper or titanium. The transparent electrode can be made of indium tin oxide, zinc tin oxide, carbon nanotube or graphene. When the fingerprint recognition module emits ultrasonic waves, it provides a high frequency alternating signal to the first driving electrode and the second driving electrode. Since the resistivity of the metal electrode is smaller than that of the transparent electrode, the use of metal electrodes for the first driving electrode and the second driving electrode can improve the identification accuracy of the fingerprint identification module.

In an exemplary embodiment, the metal electrode may have a single-layer structure or may have a multi-layer structure. When the metal electrode has a multilayer structure, the metal electrode includes: a first metal layer, a second metal layer, and a third metal layer that are stacked. The first metal layer may be made of titanium, the second metal layer may be made of aluminum, and the third metal layer may be made of titanium.

In an exemplary embodiment, the thickness of the first driving electrode and the second driving electrode is greater than 10 micrometers. Because the thickness of the first driving electrode and the second driving electrode is large, the resistance of the first driving electrode and the second driving electrode is small, and the surface uniformity is good, which can achieve better electrical performance and uniformity of ultrasonic waves. Reflect to improve the fingerprint recognition accuracy of the fingerprint recognition module.

In an exemplary embodiment, the sensing electrode may be a metal electrode, or may be a transparent electrode. The metal electrode can be made of one or more of silver, platinum, iridium, gold, aluminum, copper or titanium. The transparent electrode can be made of indium tin oxide, zinc tin oxide, carbon nanotube or graphene.

In an exemplary embodiment, the piezoelectric layer 10 is made of piezoelectric material, and the piezoelectric material includes: polyvinylidene fluoride, polyvinylidene fluoride, aluminum nitride AlN, or lead zirconate titanate series calcium Composite oxide of titanium ore structure. When the piezoelectric layer is made of polyvinylidene fluoride, the fingerprint identification module can be used in a flexible display device.

Fig. 9 is a schematic structural diagram of a fingerprint identification module provided by an exemplary embodiment. As shown in FIG. 9, the fingerprint identification module provided by an exemplary embodiment may further include a substrate 50. The substrate 50 is located on the side of the first driving electrode layer 31 away from the piezoelectric layer 10.

FIG. 9 is an example of the arrangement of the first driving electrode layer and the sensing electrode layer on the same layer as an example. The first driving electrode layer may also be arranged on the side of the sensing electrode layer away from the piezoelectric layer.

In an exemplary embodiment, the substrate 50 may be used as a contact surface with the fingerprint to be measured, or, when the fingerprint identification module is applied to a display device including a display panel, the substrate 50 may be used as a contact surface with the display panel. When the fingerprint to be measured is in contact with the contact surface, the fingerprint identification module can realize the identification of the fingerprint to be measured by transmitting ultrasonic waves to the fingerprint to be measured and receiving the ultrasonic waves reflected by the fingerprint to be measured.

In an exemplary embodiment, the substrate 50 may be a rigid substrate or a flexible substrate, where the rigid substrate may be but not limited to one or more of glass and metal sheet; the flexible substrate may be but not limited to Polyethylene terephthalate, ethylene terephthalate, polyether ether ketone, polystyrene, polycarbonate, polyarylate, polyarylate, polyimide, polyvinyl chloride , Polyethylene, one or more of textile fibers. When the substrate 50 is made of polyimide, a polyimide layer may be formed on the glass substrate, the sensing electrode layer, the piezoelectric layer, and the driving electrode layer may be formed on the polyimide layer, and the glass substrate may be peeled off.

In an exemplary embodiment, the thickness of the substrate 50 is 5 μm to 30 μm.

As shown in FIG. 9, the fingerprint identification module provided in an exemplary embodiment may further include: a second insulating layer 60 and a reflective layer 70. The second insulating layer 60 is located on the side of the second driving electrode layer 32 away from the piezoelectric layer 10; the reflective layer 70 is located on the side of the second insulating layer 60 away from the piezoelectric layer 10, and is configured to reflect ultrasonic waves.

In an exemplary embodiment, the reflective layer and the substrate can function as a supporting layer, so that the deformation degree of the piezoelectric layer will not be weakened, and the fingerprint recognition accuracy of the fingerprint recognition module can be improved.

In an exemplary embodiment, the reflective layer 70 may be made of silver or other materials that can reflect ultrasonic waves.

As shown in FIG. 9, the fingerprint identification module provided in an exemplary embodiment may further include a protective layer 80. The protective layer 80 is located on the side of the reflective layer 70 away from the second insulating layer 60, and is configured to block water and oxygen to protect the reflective layer 70.

In an exemplary embodiment, the protective layer 80 may be made of epoxy resin.

In an exemplary embodiment, the fingerprint identification module may further include: a plurality of scanning signal lines arranged in a first direction and a reading signal line arranged in a second direction.

The direction of the scan signal line is the same as the extension direction of the first drive electrode, and the extension direction of the read signal line is the same as the extension direction of the second drive electrode. The i-th scanning signal line is respectively connected to the plurality of sensing electrodes RXi1 to RXiN arranged in the first direction, and the j-th reading signal line is respectively connected to the plurality of sensing electrodes RX1j to RXMj arranged in the second direction.

When the fingerprint identification module emits ultrasonic waves, multiple scan signal lines provide invalid levels, so that fingerprint signals cannot be read from the sensing electrode layer. When the fingerprint recognition module receives ultrasonic waves, multiple scanning signal lines provide effective levels to read fingerprint signals from the sensing electrode layer.

In an exemplary embodiment, the fingerprint recognition module may further include: under the control of the scan signal line, a driving signal line that provides a driving signal to the driving electrode layer, when the first driving electrode layer and the sensing electrode layer are arranged in different layers When the driving signal line and the first driving electrode layer are arranged in different layers, the driving signal line is connected to the first driving electrode layer through the via hole arranged on the first insulating layer.

In an exemplary embodiment, the material of the second insulating layer 60 may be silicon oxide, silicon nitride, or a composite of silicon oxide and silicon nitride.

FIG. 10 is a schematic structural diagram of a display device provided by an embodiment of the disclosure. As shown in FIG. 10, an embodiment of the present disclosure also provides a display device, including a fingerprint identification module 100 and a display panel 200.

In an exemplary embodiment, the display panel 100 may be a liquid crystal display (Liquid Crystal Display, LCD for short) panel, an Organic Light-Emitting Diode (OLED) display panel, or a Quantum Dot Light (Quantum Dot Light) display panel. -Emitting Diode, QLED for short) display panel.

In an exemplary embodiment, the display device may be a liquid crystal display device, an organic light emitting diode OLED display device, or a quantum dot light emitting diode QLED display device.

In an exemplary embodiment, the display device may be a mobile phone, a tablet computer, a television, a monitor, a notebook computer, a digital photo frame, or a navigator, or may be other products or components with a display function. The other indispensable components of the display device are understood by those of ordinary skill in the art, and will not be repeated here, nor should it be used as a limitation to the present disclosure.

In an exemplary embodiment, the display panel 200 may include: an array substrate 210, a light emitting device 220, and a cover 230. The display device also includes: optical glue. The cover plate 230 is attached to the light emitting device 220 by optical glue, and the light emitting device can be sealed in a closed environment to protect the light emitting device 220.

In an exemplary embodiment, the light emitting device 220 may be an OLED light emitting device, or may be a QLED light emitting device. When the light emitting device is an OLED light emitting device, the light emitting device includes: a first electrode, a second electrode, and an organic light emitting layer disposed between the first electrode and the second electrode. When the light-emitting device is a QLED light-emitting device, the light-emitting device includes a first electrode, a second electrode, and a quantum dot light-emitting layer located between the first electrode and the second electrode.

In an exemplary embodiment, the cover 230 may be a flexible cover, which may realize the flexible foldability of the display panel.

In an exemplary embodiment, the thickness of the cover plate 230 is less than or equal to 100 microns.

The fingerprint identification module is the fingerprint identification module provided in the foregoing embodiment, and the implementation principle and effect are similar, and will not be repeated here.

In an exemplary embodiment, the area of the fingerprint identification module may be equal to the area of the display area of the display panel, so that full-screen fingerprint identification can be realized.

In an exemplary embodiment, the fingerprint identification module is located on one side of the display panel. The fingerprint recognition module can be located on the light emitting side of the display panel, or can be located on the backlight side of the display panel. The backlight side is opposite to the light emitting side.

When the fingerprint identification module is arranged on the backlight side of the display panel, the substrate in the fingerprint identification module serves as the contact surface with the display panel. Although the fingerprint recognition module is arranged under the display area of the display panel, ultrasonic waves can penetrate the display panel without affecting the display effect, and the display change of the display panel will not affect the transmission and reception of ultrasonic waves.

FIG. 11 is a flowchart of a method for driving a fingerprint identification module according to an embodiment of the disclosure. As shown in FIG. 11, the method for driving the fingerprint identification module provided by the embodiment of the present disclosure is used to drive the fingerprint identification module, and the method includes the following steps:

Step S1: Provide a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves.

Step S2. Read the fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be measured from the sensing electrode layer, so as to perform fingerprint identification according to the fingerprint signal.

In an exemplary embodiment, step S1 may include: in the first time period, providing a driving signal to the first driving electrode layer, and providing a fixed signal to the second driving electrode layer and the sensing electrode layer to drive the piezoelectric layer Ultrasound is generated; in the second time period, a driving signal is provided to the second driving electrode layer, and a fixed signal is provided to the first driving electrode layer and the sensing electrode layer to drive the piezoelectric layer to generate ultrasonic waves. The first time period is earlier or later than the second time period.

In an exemplary embodiment, the fixed signal may be a ground signal.

In an exemplary embodiment, the duration of the first time period may be greater than the duration of the second time period, or the duration of the first time period may be less than the duration of the second time period, or the duration of the first time period The duration may be equal to the duration of the second time period.

In an exemplary embodiment, providing a driving signal to the first driving electrode layer may include: providing a driving signal to the at least two first driving electrodes in a time-sharing manner to drive the piezoelectric layer to generate ultrasonic waves.

In an exemplary embodiment, when a driving signal is provided to the first driving electrode layer, at least two first driving electrodes may be used as a group of driving electrode groups. For example, the first first driving electrode, the second first driving electrode, and the third first driving electrode are used as the first group of driving electrode groups, and the second first driving electrode, the third first driving electrode and the The fourth first driving electrode serves as the second driving electrode group, and so on.

In an exemplary embodiment, when the driving signal is provided to the first driving electrode layer, the driving signal may be provided to each group of driving electrode groups in turn, or driving signals may be provided to multiple groups of driving electrode groups at the same time. For example, driving signals may be provided to the first group of driving electrode groups and the last group of driving electrode groups. When driving signals are provided to multiple driving electrode groups at the same time, the fingerprint recognition time can be reduced. Taking the driving signal provided to the first driving electrode group as an example, the driving signal is provided to the first first driving electrode and the third first driving electrode at the first time point, and the driving signal is provided to the second first driving electrode at the second time point. The driving electrode provides a driving signal, and the second time point is later than the first time point. In this way, the focus of the ultrasound can be achieved in the fingerprint area directly above the second first driving electrode, that is, the intensity or energy of the ultrasound can be enhanced.

In an exemplary embodiment, providing the driving signal to the second driving electrode layer may include: providing the driving signal to the at least two second driving electrodes in a time-sharing manner to drive the piezoelectric layer to generate ultrasonic waves.

When driving signals are provided to the second driving electrode layer, at least two second driving electrodes may be used as a group of driving electrode groups, for example, the first second driving electrode, the second second driving electrode, and the third The two driving electrodes are used as the first driving electrode group, the second second driving electrode, the third second driving electrode, and the fourth second driving electrode are used as the second driving electrode group, and so on.

In an exemplary embodiment, similar to providing the driving signal to the first driving electrode layer, when the driving signal is provided to the second driving electrode layer, the driving signal may be provided to each group of driving electrode groups in turn, or to multiple groups at the same time. The driving electrode group provides driving signals. For example, driving signals may be provided to the first group of driving electrode groups and the last group of driving electrode groups. When the driving signal is provided to the driving electrode group, the driving signal may be provided to the second driving electrode in a time-sharing manner. Taking the driving signal provided to the first driving electrode group as an example, the driving signal is provided to the first second driving electrode and the third second driving electrode at the first time point, and the driving signal is provided to the second second driving electrode at the second time point. The driving electrode provides a driving signal, and the second time point is later than the first time point. In this way, the ultrasound can be focused on the fingerprint area corresponding to the second second driving electrode, that is, the intensity or energy of the ultrasound can be enhanced.

In an exemplary embodiment, step S2 may include: providing a fixed signal to the first driving electrode layer and the second driving electrode layer, and reading from the sensing electrode layer the fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be measured .

The drawings of the embodiments of the present disclosure only refer to the structures involved in the embodiments of the present disclosure, and other structures can refer to the usual design.

Although the embodiments disclosed in the present disclosure are as described above, the content described is only the embodiments used to facilitate the understanding of the present disclosure, and is not intended to limit the present disclosure. Anyone skilled in the art to which this disclosure belongs, without departing from the spirit and scope disclosed in this disclosure, can make any modifications and changes in the implementation form and details, but the scope of patent protection of this disclosure still requires The scope defined by the appended claims shall prevail.

Claims

A fingerprint recognition module includes: a piezoelectric layer, a sensing electrode layer and a driving electrode layer; wherein,

The sensing electrode layer is located on one side of the piezoelectric layer;

The driving electrode layer includes: a first driving electrode layer and a second driving electrode layer, wherein the first driving electrode layer is located on a side of the piezoelectric layer close to the sensing electrode layer, and the second driving electrode The layer is located on the side of the piezoelectric layer away from the sensing electrode layer;

The first driving electrode layer includes: a plurality of first driving electrodes arranged in a first direction, the second driving electrode layer includes: a plurality of second driving electrodes arranged in a second direction; the first driving electrodes Extending in the second direction, the second driving electrode extends in the first direction, and the first direction is perpendicular to the second direction.
The fingerprint recognition module of claim 1, wherein the orthographic projection of each first driving electrode on the piezoelectric layer at least partially overlaps the orthographic projection of each second driving electrode on the piezoelectric layer.
The fingerprint recognition module of claim 1, wherein the sensing electrode layer comprises: a plurality of sensing electrodes arranged in a matrix, and the sensing electrodes are block electrodes;

The orthographic projection of the second driving electrode layer on the piezoelectric layer covers the orthographic projection of the sensing electrode layer on the piezoelectric layer.
4. The fingerprint identification module according to any one of claims 1 to 3, wherein the first driving electrode layer and the sensing electrode layer are provided in the same layer;

There is no overlap area between the orthographic projection of the first driving electrode layer on the piezoelectric layer and the orthographic projection of the sensing electrode layer between the piezoelectric layers.
The fingerprint identification module according to any one of claims 1 to 3, wherein the fingerprint identification module further comprises: a first insulating layer;

The first insulating layer is located on a side of the sensing electrode layer away from the piezoelectric layer, and the first driving electrode layer is located on a side of the first insulating layer away from the sensing electrode layer.
5. The fingerprint identification module of claim 5, wherein the orthographic projection of the first driving electrode layer on the piezoelectric layer at least partially overlaps the orthographic projection of the sensing electrode layer on the piezoelectric layer.
The fingerprint recognition module of claim 1, wherein the first driving electrode and the second driving electrode are strip electrodes.
8. The fingerprint recognition module of claim 7, wherein the first driving electrode and the second driving electrode are metal electrodes.
4. The fingerprint recognition module of claim 3, wherein the sensing electrode is a transparent electrode.
The fingerprint identification module according to claim 1, wherein the piezoelectric layer is made of materials comprising: polyvinylidene fluoride, aluminum nitride, polyvinylidene fluoride, or lead zirconate titanate series perovskite structure Composite oxide.
The fingerprint identification module according to claim 4 or 5, wherein the fingerprint identification module further comprises: a substrate;

The substrate is located on a side of the first driving electrode layer away from the piezoelectric layer, and is set as a contact surface with a fingerprint to be measured;

Wherein, the thickness of the substrate is 5 μm to 30 μm.
The fingerprint identification module according to claim 11, wherein the fingerprint identification module further comprises: a second insulating layer and a reflective layer;

The second insulating layer is located on a side of the second driving electrode layer away from the piezoelectric layer;

The reflective layer is located on a side of the second insulating layer away from the piezoelectric layer, and is configured to reflect ultrasonic waves.
The fingerprint identification module of claim 12, wherein the reflective layer is made of silver.
The fingerprint identification module according to claim 12, wherein the fingerprint identification module further comprises: a protective layer;

The protective layer is located on a side of the reflective layer away from the second insulating layer, and is configured to isolate water and oxygen to protect the reflective layer;

Wherein, the protective layer is made of: epoxy resin.
A display device comprising: a display panel and the fingerprint identification module according to any one of claims 1 to 14.
15. The device of claim 15, wherein the fingerprint identification module is located on one side of the display panel.
A method for driving a fingerprint identification module for driving the fingerprint identification module according to any one of claims 1 to 14, the method comprising:

Provide a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves;

The fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be tested is read from the sensing electrode layer, so as to perform fingerprint identification according to the fingerprint signal.
The method according to claim 17, wherein the providing a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves comprises:

In the first time period, providing a driving signal to the first driving electrode layer, and providing a fixed signal to the second driving electrode layer and the sensing electrode layer to drive the piezoelectric layer to generate ultrasonic waves;

In the second time period, providing a driving signal to the second driving electrode layer, and providing a fixed signal to the first driving electrode layer and the sensing electrode layer, so as to drive the piezoelectric layer to generate ultrasonic waves;

Wherein, the first time period is earlier or later than the second time period.
The method of claim 18, wherein the first driving electrode layer comprises: a plurality of first driving electrodes, and the second driving electrode layer comprises: a plurality of second driving electrodes;

The providing a driving signal to the first driving electrode layer includes:

Time-sharing providing driving signals to at least two of the first driving electrodes to drive the piezoelectric layer to generate ultrasonic waves;

The providing a driving signal to the second driving electrode layer includes:

A driving signal is provided to at least two of the second driving electrodes in a time sharing manner to drive the piezoelectric layer to generate ultrasonic waves.
The method according to any one of claims 17 to 19, wherein the reading from the sensing electrode layer the fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be measured comprises:

A fixed signal is provided to the first driving electrode layer and the second driving electrode layer, and the fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be measured is read from the sensing electrode layer.