Fingerprint recognition module and driving method thereof, and display device

Abstract

A fingerprint recognition module and a driving method and display device thereof. The fingerprint recognition module 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 layer; 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 side of the piezoelectric layer away from the sensing electrode layer; the first driving electrode layer includes: a plurality of first driving electrodes arranged along a first direction, and the second driving electrode layer includes: a plurality of second driving electrodes arranged along a second direction; the first driving electrode extends along the second direction, and the second driving electrode extends along the first direction, and the first direction is perpendicular to the second direction.

Description

Technical Field

[0001] The present disclosure relates to, but is not limited to, the field of fingerprint recognition, and relates to a fingerprint recognition module and a driving method thereof, and a display device. Background Art

[0002] Biometric identification is a technology used to distinguish different biological features, including fingerprints, palm prints, faces or irises. Fingerprints are unique and invariable features of the human body that can be distinguished from others. They are composed of ridges and valleys on the surface of the skin at the fingertips. Fingerprints can be used for personal identification because of their uniqueness and invariance. Therefore, fingerprint identification technology has attracted much attention.

[0003] Generally, fingerprint recognition technology can be divided into optical fingerprint recognition technology, silicon chip fingerprint recognition technology and ultrasonic fingerprint recognition technology. Ultrasonic fingerprint recognition technology has become a popular research direction for major manufacturers due to its security and low cost.

[0004] Ultrasonic fingerprint recognition technology emits ultrasonic waves during the fingerprint recognition process, which makes the signal-to-noise ratio of the obtained fingerprint signal lower, thereby reducing the fingerprint recognition accuracy. Summary of the invention

[0005] The following is a summary of the subject matter of the detailed description of the present disclosure. This summary is not intended to limit the scope of the claims.

[0006] In a first aspect, the present disclosure provides a fingerprint recognition module, comprising: 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 comprises: 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 layer is located on a side of the piezoelectric layer away from the sensing electrode layer;

[0007] The first driving electrode layer includes: a plurality of first driving electrodes arranged along a first direction, and the second driving electrode layer includes: a plurality of second driving electrodes arranged along a second direction; the first driving electrodes extend along the second direction, and the second driving electrodes extend along the first direction, and the first direction is perpendicular to the second direction.

[0008] In some possible implementations, an orthographic projection of each first driving electrode on the piezoelectric layer at least partially overlaps with an orthographic projection of each second driving electrode on the piezoelectric layer.

[0009] In some possible implementations, the sensing electrode layer includes: a plurality of sensing electrodes arranged in a matrix, the sensing electrodes are block electrodes; and 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.

[0010] In some possible implementations, the first driving electrode layer and the sensing electrode layer are disposed in the same layer; and an orthographic projection of the first driving electrode layer on the piezoelectric layer and an orthographic projection of the sensing electrode layer between the piezoelectric layers do not have an overlapping area.

[0011] 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 layer is located on a side of the first insulating layer away from the sensing electrode layer.

[0012] In some possible implementations, an orthographic projection of the first driving electrode layer on the piezoelectric layer at least partially overlaps with an orthographic projection of the sensing electrode layer on the piezoelectric layer.

[0013] In some possible implementations, the first driving electrode and the second driving electrode are strip electrodes.

[0014] In some possible implementations, the first driving electrode and the second driving electrode are metal electrodes.

[0015] In some possible implementations, the sensing electrode is a transparent electrode.

[0016] In some possible implementations, the piezoelectric layer is made of a material including polyvinylidene fluoride, aluminum nitride, polyvinylidene fluoride, or a lead zirconate titanate-based composite oxide with a perovskite structure.

[0017] 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 configured as a contact surface with the fingerprint to be detected; wherein the thickness of the substrate is 5 microns to 30 microns.

[0018] 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 reflective layer is located on a side of the second insulating layer away from the piezoelectric layer and is configured to reflect ultrasonic waves.

[0019] In some possible implementations, the reflective layer is made of a material including silver.

[0020] 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 configured to isolate water and oxygen to protect the reflective layer, and a material for making the protective layer includes: epoxy resin.

[0021] In a second aspect, the present disclosure further provides a display device, comprising: a display panel and the above-mentioned fingerprint recognition module.

[0022] In some possible implementations, the fingerprint recognition module is located on one side of the display panel.

[0023] In a third aspect, the present disclosure further provides a method for driving a fingerprint recognition module, for driving the above-mentioned fingerprint recognition module, the method comprising:

[0024] Providing a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves;

[0025] The fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be detected is read from the sensing electrode layer, so as to perform fingerprint recognition according to the fingerprint signal.

[0026] In some possible implementations, providing a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves includes:

[0027] In a 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, so as to drive the piezoelectric layer to generate ultrasonic waves;

[0028] In a 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;

[0029] The first time period is earlier than or later than the second time period.

[0030] In some possible implementations, 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;

[0031] Providing a driving signal to the first driving electrode layer comprises:

[0032] Providing driving signals to at least two of the first driving electrodes in a time-sharing manner, so as to drive the piezoelectric layer to generate ultrasonic waves;

[0033] Providing a driving signal to the second driving electrode layer comprises:

[0034] The driving signals are provided to at least two of the second driving electrodes in a time-sharing manner so as to drive the piezoelectric layer to generate ultrasonic waves.

[0035] In some possible implementations, reading from the sensing electrode layer a fingerprint signal converted from ultrasonic waves reflected by the piezoelectric layer according to the fingerprint to be detected includes:

[0036] A fixed signal is provided to the first driving electrode layer and the second driving electrode layer, and a fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be detected is read from the sensing electrode layer.

[0037] Other aspects will be apparent upon reading and understanding the drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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 on the technical solution of the present disclosure.

[0039] Figure 1A A schematic diagram of a fingerprint recognition module emitting ultrasonic waves;

[0040] Figure 1B A schematic diagram of a fingerprint recognition module receiving ultrasonic waves;

[0041] Figure 2 A top view of a fingerprint recognition module provided in an embodiment of the present disclosure;

[0042] Figure 3A for Figure 2 Cross-sectional view along AA direction;

[0043] Figure 3B for Figure 2 Cross-sectional view along direction BB;

[0044] Figure 4 A schematic diagram of a fingerprint recognition module implementing ultrasonic focusing in an exemplary embodiment;

[0045] Figure 5 A schematic diagram of a fingerprint recognition module implementing ultrasonic focusing in another exemplary embodiment;

[0046] Fig. 6A A schematic diagram of focusing ultrasonic waves emitted by a fingerprint recognition module to the valley of a fingerprint to be detected provided by an exemplary embodiment;

[0047] Figure 6B A schematic diagram of focusing ultrasonic waves emitted by a fingerprint recognition module on the ridge of a fingerprint to be detected provided by an exemplary embodiment;

[0048] Figure 7 A top view of a fingerprint recognition module provided for an exemplary embodiment;

[0049] Fig. 8A for Figure 7 Cross-sectional view along AA direction;

[0050] Figure 8B for Figure 7 Cross-sectional view along direction BB;

[0051] Fig. 9 A schematic diagram of the structure of a fingerprint recognition module provided by an exemplary embodiment;

[0052] Fig.10 A schematic diagram of the structure of a display device provided in an embodiment of the present disclosure;

[0053] Fig.11 A flowchart of a method for driving a fingerprint recognition module provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0054] The embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other at will.

[0055] The present disclosure describes multiple embodiments, but the description is exemplary rather than restrictive, and it will be apparent to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present disclosure. 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 may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0056] The present disclosure includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features, and elements disclosed in the present disclosure may also be combined with any conventional features or elements to form a technical solution defined by the claims. Any features or elements of any embodiment may 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 the present disclosure may 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 attached claims and their equivalents. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0057] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The words "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 "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0058] Figure 1A The following is a schematic diagram of a fingerprint recognition module emitting ultrasonic waves. Figure 1A As shown, 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 and can be excited by an alternating voltage to produce an inverse piezoelectric effect. As shown in FIG1 , when an alternating voltage is input to the upper electrode 11 and the lower electrode 12, the piezoelectric layer 13 will deform due to the inverse piezoelectric effect, driving the film layers above and below the piezoelectric layer 13 to vibrate together, thereby generating ultrasonic waves and emitting them outward.

[0059] Figure 1B The figure is a schematic diagram of a fingerprint recognition module receiving ultrasonic waves. Figure 1B As shown, the ultrasonic wave emitted by the fingerprint recognition module is reflected by the fingerprint to be tested 500, and the reflected ultrasonic wave is converted into an alternating voltage 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 to be tested 500 includes valleys 510 and ridges 520, they have different reflection capabilities for ultrasonic waves, resulting in different intensities of ultrasonic waves reflected by the valleys 510 and ridges 520. Therefore, the position information of the valleys and ridges in the fingerprint to be tested can be obtained by the alternating voltage received by the receiving electrode, so that fingerprint recognition can be realized.

[0060] Figure 2 A top view of a fingerprint recognition module provided in an embodiment of the present disclosure, Figure 3A for Figure 2 Cross-sectional view along AA direction, Figure 3B for Figure 2 Cross-sectional view along the BB direction. Figure 2As shown in FIG. 3 , the fingerprint recognition module provided by the embodiment of the present disclosure is used to recognize a fingerprint to be detected. The fingerprint recognition module includes: a piezoelectric layer 10 , a sensing electrode layer 20 and a driving electrode layer 30 .

[0061] 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 one side of the piezoelectric layer 10 close to the sensing electrode layer 20 , and the second driving electrode layer 32 is located on one side of the piezoelectric layer 10 away from the sensing electrode layer 20 .

[0062] The first driving electrode layer 31 includes: a plurality of first driving electrodes TX_X1 to TX_XM arranged along the first direction D1, and the second driving electrode layer 32 includes: a plurality of second driving electrodes TX_Y1 to TX_YN arranged along the second direction D2; the first driving electrodes extend along the second direction, and the second driving electrodes extend along the first direction, and the first direction D1 is perpendicular to the second direction D2.

[0063] A plurality of first driving electrodes TX_X1 to TX_XM are disposed on the same layer, and a plurality of second driving electrodes TX_Y1 to TX_YN are disposed on the same layer.

[0064] The extending direction of the first driving electrode is the same as the arrangement direction of the second driving electrodes, and the extending direction of the second driving electrode is the same as the arrangement direction of the first driving electrodes, that is, the extending direction of the first driving electrode is perpendicular to the extending direction of the second driving electrode.

[0065] Each first driving electrode in the first driving electrode layer can be controlled individually, for example, by providing a driving signal to the first driving electrode in time-sharing, so as to achieve focusing of ultrasound waves, that is, to enhance the intensity or energy of ultrasound waves. Each second driving electrode in the second driving electrode layer can be controlled individually, for example, by providing a driving signal to the second driving electrode in time-sharing, so as to achieve focusing of ultrasound waves. Since the arrangement directions of the multiple first driving electrodes are different from the arrangement directions of the multiple second driving electrodes, the fingerprint recognition module can achieve focusing of ultrasound waves in two dimensions.

[0066] In an exemplary embodiment, the piezoelectric layer may be a planar structure, or may include: a piezoelectric structure arranged in an array.

[0067] 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 can constitute an ultrasonic transmitting component. The sensing electrode layer, the second driving electrode layer and the piezoelectric material layer can constitute an ultrasonic receiving component.

[0068] When the fingerprint recognition module transmits ultrasonic waves, the sensing electrode layer can be grounded, and driving signals can be provided to the first driving electrode layer and the second driving electrode layer respectively, and the piezoelectric layer 10 will deform due to the inverse piezoelectric effect, thereby generating ultrasonic waves and emitting them outward. 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 ultrasonic signal reflected back from the sensing electrode layer can be read, thereby realizing fingerprint recognition.

[0069] In an exemplary embodiment, when the fingerprint recognition module transmits ultrasonic waves, a driving signal is provided to the first driving electrode layer in a first time period, and a driving signal is provided to the second driving electrode layer in a second time period. The end 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 end time of the second time period.

[0070] When providing a driving signal to the first driving electrode layer, at least two first driving electrodes may be used as a driving electrode group. 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 driving electrode group, the second first driving electrode TX_X2, the third first driving electrode TX_X3 and the fourth first driving electrode TX_X4 are used as the second driving electrode group, and so on.

[0071] Figure 4 is a schematic diagram of a fingerprint recognition module implementing ultrasonic focusing in an exemplary embodiment, Figure 5 A schematic diagram of a fingerprint recognition module implementing ultrasonic focusing in another exemplary embodiment. In an exemplary embodiment, when providing a driving signal to the first driving electrode layer, the driving signal may be provided to each driving electrode group in turn, or the driving signal may be provided to multiple driving electrode groups at the same time. For example, the driving signal may be provided to the first driving electrode group and the last driving electrode group. Figure 4 The following is an example of providing a driving signal to each driving electrode group in sequence. Figure 5 The description is given by taking the example of providing driving signals to the first driving electrode group and the last driving electrode group. When driving signals are provided to multiple driving electrode groups at the same time, the fingerprint recognition time can be reduced.

[0072] When providing a driving signal to the driving electrode group, the driving signal can be provided to at least two first driving electrodes in the driving electrode group in a time-sharing manner. Taking the provision of a driving signal to the first driving electrode group as an example, a driving signal is provided to the first first driving electrode TX_X1 and the third first driving electrode TX_X3 at a first time point, and a driving signal is provided to the second first driving electrode TX_X2 at a second time point, and the second time point is later than the first time point. In this way, the focusing of the ultrasonic wave can be achieved in the fingerprint area corresponding to the second first driving electrode TX_X2, that is, the intensity or energy of the ultrasonic wave can be enhanced. Figure 4 and Figure 5 The description is made by taking the example of providing a driving signal to the first driving electrode layer.

[0073] When providing a driving signal to the second driving electrode layer, at least two second driving electrodes can be used as a driving electrode group, for example, the first second driving electrode TX_Y1, the second second driving electrode TX_Y2 and the third second driving electrode TX_Y3 can be used as the first driving electrode group, the second second driving electrode TX_Y2, the third second driving electrode TX_Y3 and the fourth second driving electrode TX_Y4 can be used as the second driving electrode group, and so on.

[0074] In an exemplary embodiment, similar to providing a driving signal to the first driving electrode layer, when providing a driving signal to the second driving electrode layer, a driving signal may be provided to each driving electrode group in sequence, or a driving signal may be provided to multiple driving electrode groups at the same time. For example, a driving signal may be provided to the first driving electrode group and the last driving electrode group.

[0075] In an exemplary embodiment, when providing a driving signal to the second driving electrode layer, the driving signal can be provided to the driving electrode group in sequence. When providing a driving signal to the driving electrode group, the driving signal can be provided to the second driving electrode in a time-sharing manner. Taking the provision of a driving signal to the first driving electrode group as an example, a driving signal is provided to the first second driving electrode TX_Y1 and the third second driving electrode TX_Y3 at a first time point, and a driving signal is provided to the second second driving electrode TX_Y2 at a second time point, and the second time point is later than the first time point. In this way, the focusing of the ultrasonic wave can be achieved in the fingerprint area corresponding to the second second driving electrode TX_Y2, that is, the intensity or energy of the ultrasonic wave is enhanced.

[0076] Fig. 6A A schematic diagram of an exemplary embodiment of focusing ultrasonic waves emitted by a fingerprint recognition module on the valley of a fingerprint to be detected. Figure 6B A schematic diagram of an exemplary embodiment of a fingerprint recognition module providing ultrasound waves emitted and focused on the ridge of a fingerprint to be detected. Fig. 6AAs shown, 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 to be tested 500, the energy or intensity of the ultrasonic wave reflected by the valley 510 is greater. Figure 6B As shown in FIG. 1 , when the ultrasonic wave emitted by the fingerprint recognition module is focused on the ridge 520 of the fingerprint 500 to be detected, the energy or intensity of the ultrasonic wave reflected by the ridge 520 is smaller. Therefore, the difference in the intensity and energy of the ultrasonic wave reflected by the valley 510 and the ridge 520 of the fingerprint 500 to be detected is also larger, which can help improve the fingerprint recognition performance. In addition, as Fig. 6A and Figure 6B As shown, 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 improve the fingerprint recognition performance.

[0077] The fingerprint recognition module provided by the embodiment 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 layer; 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 side of the piezoelectric layer away from the sensing electrode layer; the first driving electrode layer includes: a plurality of first driving electrodes arranged along the first direction, and the second driving electrode layer includes: a plurality of second driving electrodes arranged along the second direction; the first driving electrode extends along the second direction, and the second driving electrode extends along the first direction. The technical solution provided by the present disclosure is provided by setting a first driving electrode layer and a second driving electrode layer including different layers, and each driving electrode layer includes: a plurality of driving electrodes, and two-dimensional focusing of ultrasonic waves can be achieved by driving the plurality of driving electrodes separately, which can improve the intensity or energy of the emitted ultrasonic waves on the one hand, and on the other hand, can make the emitted ultrasonic waves have better directionality, reduce the crosstalk between the valleys and ridges of the fingerprint, increase the signal-to-noise ratio of the fingerprint signal, and improve the fingerprint recognition accuracy.

[0078] In an exemplary embodiment, when the fingerprint recognition module increases the intensity or energy of the emitted ultrasonic wave by focusing the ultrasonic wave, the fingerprint recognition module can not only realize fingerprint recognition, but also penetrate the finger to distinguish whether the fingerprint is real skin.

[0079] In an exemplary embodiment, for each first driving electrode, the orthographic projection of the first driving electrode on the piezoelectric layer at least partially overlaps with the orthographic projection of each second driving electrode on the piezoelectric layer, that is, the orthographic projection of each first driving electrode on the piezoelectric layer 10 at least partially overlaps with 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 at least partially overlaps with the orthographic projection of each first driving electrode on the piezoelectric layer 10.

[0080] In an exemplary embodiment, Figure 2As shown, in a fingerprint recognition module provided by an exemplary embodiment, the sensing electrode layer 20 includes: a plurality of sensing electrodes arranged in a matrix, namely RX11 to RXMN, the sensing electrodes are block electrodes, wherein 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.

[0081] 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, and the number of the sensing electrodes may be equal to the number of the pixel units, or the area of ​​the sensing electrode may be greater than the area of ​​the pixel unit, and the number of the sensing electrodes may be less than the number of the pixel units. The number and area of ​​the sensing electrodes may be determined according to the fingerprint recognition accuracy.

[0082] In an exemplary embodiment, the number of first driving electrodes may be equal to M or may not be equal to M, and the number of second driving electrodes may be equal to N or may not be equal to N. M, N, the number of first driving electrodes, and the number of second driving electrodes may be determined according to fingerprint recognition accuracy.

[0083] 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.

[0084] In an exemplary embodiment, when the fingerprint recognition module receives ultrasonic waves, it can adopt sequential reading along the first direction, or it can adopt interval reading along the first direction.

[0085] In an exemplary embodiment, Figure 2 As shown in FIG. 3 , the first driving electrode layer 31 and the sensing electrode layer 20 are disposed in the same layer, and there is no overlapping area between the orthographic projection of the first driving electrode layer 31 on the piezoelectric layer and the orthographic projection of the sensing electrode layer 20 between the piezoelectric layers.

[0086] Figure 7 A top view of a fingerprint recognition module provided by an exemplary embodiment. Fig. 8A for Figure 7 Cross-sectional view along AA direction, Figure 8B for Figure 7 Cross-sectional view along the BB direction. Figure 7 As shown in FIG8 , an exemplary fingerprint recognition module further includes: a first insulating layer 40 .

[0087] The first insulating layer 40 is located on a side of the sensing electrode layer 20 away from the piezoelectric layer 10 , and the first driving electrode layer 31 is located on a side of the first insulating layer 40 away from the sensing electrode layer 20 .

[0088] 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 orthographic projection of the first driving electrode TX_Xi on the piezoelectric layer may not have an overlapping area with the orthographic projections of the plurality of sensing electrodes RXi1 to RXiN arranged along the second direction on the piezoelectric layer. Figure 7 FIG. 8 is described by taking the example that the orthographic projection of each first driving electrode on the piezoelectric layer at least partially overlaps with the orthographic projection of the sensing electrode on the piezoelectric layer.

[0089] In an exemplary embodiment, the sensing electrode layer and the first driving electrode layer are arranged in different layers. Under the condition of the same area of ​​the fingerprint recognition module, the area of ​​each sensing electrode in the sensing electrode layer or the number of sensing electrodes can be increased to improve the fingerprint recognition accuracy of the fingerprint recognition module.

[0090] In an exemplary embodiment, the first insulating layer 40 may be made of silicon oxide, silicon nitride, or a composite of silicon oxide and silicon nitride.

[0091] In an exemplary embodiment, the first driving electrode and the second driving electrode may be strip electrodes.

[0092] In an exemplary embodiment, the first drive electrode and the second drive electrode may be metal electrodes, or may be transparent electrodes. The metal electrode may be made of one or more of silver, platinum, iridium, gold, aluminum, copper or titanium. The transparent electrode may be made of indium tin oxide, zinc tin oxide, carbon nanotubes or graphene. When the fingerprint recognition module emits ultrasonic waves, a high-frequency alternating signal is provided to the first drive electrode and the second drive electrode. Since the resistivity of the metal electrode is smaller than that of the transparent electrode, the use of metal electrodes for the first drive electrode and the second drive electrode can improve the recognition accuracy of the fingerprint recognition module.

[0093] In an exemplary embodiment, the metal electrode may be a single-layer structure or a multi-layer structure. When the metal electrode is a multi-layer structure, the metal electrode includes: a first metal layer, a second metal layer, and a third metal layer 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.

[0094] In an exemplary embodiment, the thickness of the first driving electrode and the second driving electrode is greater than 10 microns. Since the thickness of the first driving electrode and the second driving electrode is relatively large, the resistance of the first driving electrode and the second driving electrode is relatively small, and the surface uniformity is relatively good, so that better electrical performance and uniform reflection of ultrasonic waves can be achieved, so as to improve the fingerprint recognition accuracy of the fingerprint recognition module.

[0095] In an exemplary embodiment, the sensing electrode may be a metal electrode or a transparent electrode. The metal electrode may be made of one or more of silver, platinum, iridium, gold, aluminum, copper or titanium. The transparent electrode may be made of indium tin oxide, zinc tin oxide, carbon nanotube or graphene.

[0096] In an exemplary embodiment, the material of the piezoelectric layer 10 includes: a piezoelectric material, and the piezoelectric material includes: polyvinylidene fluoride, polyvinylidene fluoride, aluminum nitride AlN or a composite oxide of a perovskite structure of a lead zirconate titanate system. When the material of the piezoelectric layer is polyvinylidene fluoride, the fingerprint recognition module can be applied to a flexible display device.

[0097] Fig. 9 FIG. 1 is a schematic diagram of the structure of a fingerprint recognition module provided by an exemplary embodiment. Fig. 9 As shown, a fingerprint recognition module provided by an exemplary embodiment may further include: a substrate 50. The substrate 50 is located on a side of the first driving electrode layer 31 away from the piezoelectric layer 10.

[0098] Fig. 9 The description is given by taking the case where the first driving electrode layer and the sensing electrode layer are arranged on the same layer as an example. The first driving electrode layer may also be arranged on a side of the sensing electrode layer away from the piezoelectric layer.

[0099] In an exemplary embodiment, the substrate 50 can be used as a contact surface with the fingerprint to be detected, or, when the fingerprint recognition module is applied to a display device including a display panel, the substrate 50 can be used as a contact surface with the display panel. When the fingerprint to be detected contacts the contact surface, the fingerprint recognition module can recognize the fingerprint to be detected by transmitting ultrasonic waves to the fingerprint to be detected and receiving ultrasonic waves reflected by the fingerprint to be detected.

[0100] In an exemplary embodiment, the substrate 50 may be a rigid substrate or a flexible substrate, wherein the rigid substrate may be, but is not limited to, one or more of glass and metal foil; the flexible substrate may be, but is not limited to, one or more of polyethylene terephthalate, polyethylene terephthalate, polyetheretherketone, polystyrene, polycarbonate, polyarylate, polyarylate, polyimide, polyvinyl chloride, polyethylene, and textile fiber. When the substrate 50 is made of polyimide, a polyimide layer may be formed on a glass substrate, a sensing electrode layer, a piezoelectric layer, and a driving electrode layer may be formed on the polyimide layer, and the glass substrate may be peeled off.

[0101] In an exemplary embodiment, the thickness of the substrate 50 is 5 micrometers to 30 micrometers.

[0102] like Fig. 9As shown, the fingerprint recognition 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.

[0103] In an exemplary embodiment, the reflective layer and the substrate can play the role of 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.

[0104] In an exemplary embodiment, the material of the reflective layer 70 may include silver, or other materials that can reflect ultrasound.

[0105] like Fig. 9 As shown, the fingerprint recognition module provided in an exemplary embodiment may further include a protective layer 80. The protective layer 80 is located on a side of the reflective layer 70 away from the second insulating layer 60 and is configured to isolate water and oxygen to protect the reflective layer 70.

[0106] In an exemplary embodiment, the material of the protective layer 80 may include epoxy resin.

[0107] In an exemplary embodiment, the fingerprint recognition module may further include: a plurality of scanning signal lines arranged along a first direction and a plurality of reading signal lines arranged along a second direction.

[0108] The direction of the scanning signal line is the same as the extension direction of the first driving electrode, and the extension direction of the reading signal line is the same as the extension direction of the second driving electrode. The i-th scanning signal line is respectively connected to a plurality of sensing electrodes RXi1 to RXiN arranged along the first direction, and the j-th reading signal line is respectively connected to a plurality of sensing electrodes RX1j to RXMj arranged along the second direction.

[0109] When the fingerprint recognition module transmits ultrasonic waves, the multiple scanning signal lines provide invalid levels so that the fingerprint signal cannot be read from the sensing electrode layer. When the fingerprint recognition module receives ultrasonic waves, the multiple scanning signal lines provide valid levels to enable the fingerprint signal to be read from the sensing electrode layer.

[0110] In an exemplary embodiment, the fingerprint recognition module may also include: under the control of the scanning 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, and 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 a via hole arranged on the first insulating layer.

[0111] In an exemplary embodiment, the second insulating layer 60 may be made of silicon oxide, silicon nitride, or a composite of silicon oxide and silicon nitride.

[0112] Fig.10 Schematic diagram of the structure of the display device provided by the embodiment of the present disclosure. Fig.10 As shown, an embodiment of the present disclosure further provides a display device, including: a display panel 100 and a fingerprint recognition module 200 .

[0113] In an exemplary embodiment, the display panel 100 may be a liquid crystal display (LCD) panel, an organic light-emitting diode (OLED) display panel, or a quantum dot light-emitting diode (QLED) display panel.

[0114] 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.

[0115] In an exemplary embodiment, the display device may be a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame or a navigator, or may be other products or components with a display function. Other essential components of the display device are well understood by those skilled in the art, and are not described in detail herein, nor should they be used as limitations to the present disclosure.

[0116] In an exemplary embodiment, the display panel 200 may include: an array substrate 210, a light emitting device 220 and a cover plate 230. The display device further includes: an optical adhesive. The cover plate 230 is attached to the light emitting device 220 by the optical adhesive, and the light emitting device can be sealed in a closed environment to protect the light emitting device 220.

[0117] 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 disposed between the first electrode and the second electrode.

[0118] In an exemplary embodiment, the cover plate 230 may be a flexible cover plate, which may enable the display panel to be flexible and foldable.

[0119] In an exemplary embodiment, the thickness of the cover plate 230 is less than or equal to 100 micrometers.

[0120] The fingerprint recognition module is the fingerprint recognition module provided in the aforementioned embodiment, and its implementation principle and implementation effect are similar, which will not be repeated here.

[0121] In an exemplary embodiment, the area of ​​the fingerprint recognition module may be equal to the area of ​​the display region of the display panel, so that full-screen fingerprint recognition may be achieved.

[0122] In an exemplary embodiment, the fingerprint recognition 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 arranged opposite to the light-emitting side.

[0123] When the fingerprint recognition module is set on the backlight side of the display panel, the substrate in the fingerprint recognition module serves as the contact surface with the display panel. Although the fingerprint recognition module is set below the display area of ​​the display panel, ultrasound can penetrate the display panel and will not affect the display effect, and changes in the display of the display panel will not affect the transmission and reception of ultrasound.

[0124] Fig.11 Flow chart of the driving method of the fingerprint recognition module provided by the embodiment of the present disclosure. Fig.11 As shown, the driving method of the fingerprint recognition module provided by the embodiment of the present disclosure is used to drive the fingerprint recognition module, and the method includes the following steps:

[0125] Step S1: providing a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves.

[0126] Step S2: reading the fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be detected from the sensing electrode layer, so as to perform fingerprint recognition according to the fingerprint signal.

[0127] The fingerprint recognition module is the fingerprint recognition module provided in the aforementioned embodiment, and its implementation principle and implementation effect are similar, which will not be repeated here.

[0128] In an exemplary embodiment, step S1 may include: in a 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 a 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. The first time period is earlier or later than the second time period.

[0129] In an exemplary embodiment, the fixed signal may be a ground signal.

[0130] 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 may be equal to the duration of the second time period.

[0131] In an exemplary embodiment, providing the driving signal to the first driving electrode layer may include: providing the driving signal to at least two first driving electrodes in a time-sharing manner to drive the piezoelectric layer to generate ultrasonic waves.

[0132] In an exemplary embodiment, when providing a driving signal to the first driving electrode layer, at least two first driving electrodes may be used as a driving electrode group. For example, the first first driving electrode, the second first driving electrode and the third first driving electrode are used as the first driving electrode group, the second first driving electrode, the third first driving electrode and the fourth first driving electrode are used as the second driving electrode group, and so on.

[0133] In an exemplary embodiment, when providing a driving signal to the first driving electrode layer, the driving signal can be provided to each driving electrode group in turn, or the driving signal can be provided to multiple driving electrode groups at the same time. For example, the driving signal can be provided to the first driving electrode group and the last driving electrode group. When the driving signal is provided to multiple driving electrode groups at the same time, the fingerprint recognition time can be reduced. Taking the provision of a driving signal to the first driving electrode group as an example, a driving signal is provided to the first first driving electrode and the third first driving electrode at a first time point, and a driving signal is provided to the second first driving electrode at a second time point, and the second time point is later than the first time point. In this way, the focusing of the ultrasonic wave can be achieved in the fingerprint area corresponding to the second first driving electrode directly above the second first driving electrode, that is, the intensity or energy of the ultrasonic wave is enhanced.

[0134] In an exemplary embodiment, providing the driving signal to the second driving electrode layer may include: providing the driving signal to at least two second driving electrodes in a time-sharing manner to drive the piezoelectric layer to generate ultrasonic waves.

[0135] When providing a driving signal to the second driving electrode layer, at least two second driving electrodes can be used as a driving electrode group, for example, the first second driving electrode, the second second driving electrode and the third second driving electrode can be used as the first driving electrode group, the second second driving electrode, the third second driving electrode and the fourth second driving electrode can be used as the second driving electrode group, and so on.

[0136] In an exemplary embodiment, similar to providing a driving signal to the first driving electrode layer, when providing a driving signal to the second driving electrode layer, a driving signal can be provided to each driving electrode group in turn, or a driving signal can be provided to multiple driving electrode groups at the same time. For example, a driving signal can be provided to the first driving electrode group and the last driving electrode group. When providing a driving signal to the driving electrode group, the driving signal can be provided to the second driving electrode in a time-sharing manner. Taking providing a driving signal to the first driving electrode group as an example, a driving signal is provided to the first second driving electrode and the third second driving electrode at a first time point, and a driving signal is provided to the second second driving electrode at a second time point, and the second time point is later than the first time point. In this way, the focusing of the ultrasonic wave can be achieved in the fingerprint area corresponding to the second second driving electrode directly above the second second driving electrode, that is, the intensity or energy of the ultrasonic wave is enhanced.

[0137] 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 a fingerprint signal converted by the piezoelectric layer according to ultrasonic waves reflected by the fingerprint to be detected from the sensing electrode layer.

[0138] The drawings of the embodiments of the present disclosure only involve the structures involved in the embodiments of the present disclosure, and other structures may refer to the general design.

[0139] Although the embodiments disclosed in the present disclosure are as above, the contents described are only embodiments adopted to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. Any technician in the field to which the present disclosure belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present disclosure, but the scope of patent protection of the present disclosure shall still be subject to the scope defined in the attached claims.

Claims

1. A fingerprint recognition module, comprising: piezoelectric layer, sensing electrode layer and 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 layer is located on a side of the piezoelectric layer far from the sensing electrode layer; 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; The first driving electrode layer includes: a plurality of first driving electrodes arranged along a first direction, and the second driving electrode layer includes: a plurality of second driving electrodes arranged along a second direction; the first driving electrodes extend along the second direction, and the second driving electrodes extend along the first direction, and the first direction is perpendicular to the second direction; The sensing electrode layer comprises: a plurality of sensing electrodes arranged in a matrix, wherein the sensing electrodes are block electrodes; The first driving electrode layer and the sensing electrode layer are arranged in the same layer, wherein an orthographic projection of the first driving electrode layer on the piezoelectric layer and an orthographic projection of the sensing electrode layer between the piezoelectric layers do not have an overlapping area; Alternatively, 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 layer is located on a side of the first insulating layer away from the sensing electrode layer.

2. The fingerprint recognition module according to claim 1, wherein: The orthographic projection of each first driving electrode on the piezoelectric layer at least partially overlaps with the orthographic projection of each second driving electrode on the piezoelectric layer.

3. The fingerprint recognition module according to claim 1, wherein: The fingerprint recognition module further includes: when the first insulating layer is formed, the orthographic projection of the first driving electrode layer on the piezoelectric layer at least partially overlaps with the orthographic projection of the sensing electrode layer on the piezoelectric layer.

4. The fingerprint recognition module according to claim 1, wherein: The first driving electrode and the second driving electrode are strip electrodes.

5. The fingerprint recognition module according to claim 4, wherein: The first driving electrode and the second driving electrode are metal electrodes.

6. The fingerprint recognition module according to claim 1, wherein: The sensing electrode is a transparent electrode.

7. The fingerprint recognition module according to claim 1, wherein: The piezoelectric layer is made of materials including polyvinylidene fluoride, aluminum nitride, polyvinylidene fluoride or a composite oxide of a perovskite structure of lead zirconate titanate series.

8. The fingerprint recognition module according to claim 1, wherein: 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 configured to be in contact with the fingerprint to be detected; Wherein, the thickness of the substrate is 5 micrometers to 30 micrometers.

9. The fingerprint recognition module according to claim 8, wherein: 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 reflective layer is located on a side of the second insulating layer away from the piezoelectric layer and is configured to reflect ultrasonic waves.

10. The fingerprint recognition module according to claim 9, wherein: The reflective layer is made of silver.

11. The fingerprint recognition module according to claim 9, wherein: The fingerprint recognition module further includes: a protection 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 so as to protect the reflective layer; Wherein, the material for making the protective layer includes: epoxy resin.

12. A display device, comprising: A display panel and a fingerprint recognition module as claimed in any one of claims 1 to 11.

13. The device according to claim 12, wherein: The fingerprint recognition module is located on one side of the display panel.

14. A method for driving a fingerprint recognition module, for driving the fingerprint recognition module according to any one of claims 1 to 11, the method comprising: Providing 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 detected is read from the sensing electrode layer, so as to perform fingerprint recognition according to the fingerprint signal.

15. The method according to claim 14, wherein: Providing a driving signal to the driving electrode layer to drive the piezoelectric layer to generate ultrasonic waves comprises: In a 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, so as to drive the piezoelectric layer to generate ultrasonic waves; In a 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; The first time period is earlier or later than the second time period.

16. The method according to claim 15, wherein: 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; Providing a driving signal to the first driving electrode layer comprises: Providing driving signals to at least two of the first driving electrodes in a time-sharing manner to drive the piezoelectric layer to generate ultrasonic waves; Providing a driving signal to the second driving electrode layer comprises: The 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.

17. The method according to any one of claims 14 to 16, wherein: The step of reading the fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be detected from the sensing electrode layer comprises: A fixed signal is provided to the first driving electrode layer and the second driving electrode layer, and a fingerprint signal converted by the piezoelectric layer according to the ultrasonic wave reflected by the fingerprint to be detected is read from the sensing electrode layer.

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