WO2021175138A1

WO2021175138A1 - Display module and electronic device

Info

Publication number: WO2021175138A1
Application number: PCT/CN2021/077765
Authority: WO
Inventors: 刘宣宣
Original assignee: 欧菲光集团股份有限公司; 江西欧迈斯微电子有限公司
Priority date: 2020-03-06
Filing date: 2021-02-25
Publication date: 2021-09-10
Also published as: CN111428584B; CN111428584A

Abstract

A display module (1000) and an electronic device (10). The display module (1000) comprises a display panel (100), an ultrasonic sensor (200), and a composite layer (300). The display panel (100) comprises a first surface (110) and a second surface (120) disposed oppositely. The ultrasonic sensor (200) is provided on the side of the second surface (120) away from the first surface (110); and the ultrasonic sensor (200) can transmit ultrasonic waves passing through the display panel (100) and receive reflected ultrasonic waves. The composite layer (300) is provided between the display panel (100) and the ultrasonic sensor (200). The composite layer (300) comprises an adhesive layer (310), an electromagnetic shielding layer (320), and a conductive adhesive layer (330) that are laminated and attached in sequence; the adhesive layer (310) is attached to the second surface (120); the conductive adhesive layer (330) is attached to the ultrasonic sensor (200); and the conductive adhesive layer (330) is grounded to shield electromagnetic signals. The thickness of the adhesive layer (310) is about 0.003 mm to about 0.006 mm, the thickness of the electromagnetic shielding layer (320) is about 0.006 mm to about 0.009 mm, and the thickness of the conductive adhesive layer (330) is about 0.003 mm to about 0.006 mm.

Description

Display module and electronic equipment

Cross-references to related applications

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office, the application number is 202010151809X, and the invention title is "Display Module and Electronic Equipment" on March 6, 2020, the entire content of which is incorporated into this application by reference.

Technical field

This application relates to the technical field of fingerprint identification, and in particular to a display module and electronic equipment.

technical background

In the related art, the ultrasonic fingerprint module is attached to an organic electro-laser display (OLED) display panel using glue, so that the OLED display panel can have a fingerprint recognition function. However, the ultrasonic fingerprint module will radiate a lot of electromagnetic waves when it is working, which will cause electromagnetic interference (EMI, Electromagnetic Interference) to the normal operation of the OLED display panel. For example, the color difference of the OLED display panel due to electromagnetic interference during the lighting process or due to electromagnetic The interference causes false touches on the display panel with touch function. In addition, the OLED display panel also generates electromagnetic waves during operation, which affects the ultrasonic fingerprint module, resulting in uneven fingerprint imaging.

Summary of the invention

According to various embodiments of the present application, a display module and an electronic device are provided.

A display module includes:

The display panel includes a first surface and a second surface that are oppositely arranged;

An ultrasonic sensor arranged on a side of the second surface away from the first surface, the ultrasonic sensor can emit ultrasonic waves that penetrate the display panel and receive reflected ultrasonic waves; and

The composite layer is arranged between the display panel and the ultrasonic sensor. The composite layer includes an adhesive layer, an electromagnetic shielding layer and a conductive adhesive layer that are laminated and laminated in sequence, and the adhesive layer is attached to the On the second surface, the conductive adhesive layer is attached to the ultrasonic sensor, and the conductive adhesive layer is grounded; wherein the thickness of the adhesive layer is about 0.003 mm to about 0.006 mm, and the electromagnetic shield The thickness of the layer is about 0.006 mm to about 0.009 mm, and the thickness of the conductive adhesive layer is about 0.003 mm to about 0.006 mm.

For the above display module, the composite layer has a good electromagnetic shielding effect and can realize EMI protection, and the thickness range of each layered structure in the composite layer can be set to enable the ultrasonic sensor to collect the reflected and clear ultrasonic signal and generate a clear fingerprint The image satisfies fingerprint imaging and realizes the fingerprint unlocking function.

In one of the embodiments, the thickness of the adhesive layer is about 0.003 mm to about 0.004 mm, and the thickness of the conductive adhesive layer is about 0.003 mm to about 0.004 mm. This can ensure that the fingerprint image is clear when the electronic device is working at a high temperature.

In one of the embodiments, the display module further includes a light-shielding buffer layer, and the light-shielding buffer layer is attached to the second surface around the composite layer. In this way, the light-shielding buffer layer can not only block the penetration of light in the edge area of the display panel, but also protect the ultrasonic sensor when the display module is impacted or external force is applied, so that the ultrasonic sensor is not easily damaged, and the service life of the display module is ensured.

In one of the embodiments, the display module further includes a heat dissipation layer, and the heat dissipation layer is disposed on a side of the light-shielding buffer layer away from the second surface around the composite layer. In this way, rapid heat dissipation is achieved.

In one of the embodiments, the display module includes a middle shell and a conductive member, the middle shell is connected to a side of the heat dissipation layer away from the display panel, and the conductive adhesive layer is connected to the conductive member through the conductive member. The middle shell is connected to realize the grounding of the conductive adhesive layer through the middle shell. In this way, the use of the conductive adhesive layer to connect to the circuit board through the conductive member can realize the convenient and rapid grounding of the conductive adhesive layer, thereby realizing EMI protection.

In one of the embodiments, the display module includes a circuit board and a conductive member, the circuit board is electrically connected to the ultrasonic sensor, and the conductive adhesive layer is connected to the circuit board through the conductive member to The grounding of the conductive adhesive layer is realized by the circuit board. In this way, the middle casing may include the middle frame of the electronic device, and the conductive adhesive layer is connected to the middle casing through the conductive member to realize the convenient and fast grounding of the conductive adhesive layer, thereby realizing EMI protection.

In one of the embodiments, at least one of the adhesive layer and the conductive adhesive layer includes copper powder with a particle size of about 0 mm to about 0.001 mm, and nickel powder with a particle size of about 0 mm to about 0.001 mm. , Carbon powder with a particle size of about 0mm to about 0.001mm. In this way, the size settings of copper powder, nickel powder and carbon powder can avoid black spots in fingerprint imaging.

In one of the embodiments, in the adhesive layer or the conductive adhesive layer, the copper powder has a particle size of about 0.0005 mm to about 0.001 mm, and the nickel powder has a particle size of about 0.0005 mm to about 0.001 mm. It is about 0.001 mm, and the particle size of the carbon powder is about 0.0005 mm to about 0.0001 mm. In this way, the processing cost of copper powder, nickel powder and carbon powder is saved.

In one of the embodiments, the ultrasonic sensor includes a thin film transistor (TFT) substrate, a piezoelectric layer and an electrode layer, the TFT substrate is attached to the conductive adhesive layer, and the piezoelectric layer is provided on the TFT substrate Between the electrode layer and the electrode layer and used for transmitting and receiving ultrasonic waves. In this way, based on the characteristics of the respective materials of the TFT substrate, the electrode layer, and the piezoelectric layer, by bonding the TFT substrate to the display panel so that the entire ultrasonic sensor is bonded to the bottom of the display panel, the stability of bonding can be improved, and the bonding Easy to fit.

In one of the embodiments, the ultrasonic sensor further includes a protective layer connected to a side of the electrode layer away from the piezoelectric layer.

In one of the embodiments, the TFT substrate includes a substrate, a plurality of thin film transistors arranged in an array on the substrate, and a circuit for connecting the thin film transistors on the substrate.

In one of the embodiments, the display module further includes a protective cover plate, and the protective cover plate is connected to the first surface. In this way, the protective cover can protect the display panel from external interference and enhance the structural strength.

In one of the embodiments, the electromagnetic shielding layer is a metal foil layer. In this way, the shielding layer has a better shielding effect.

In one of the embodiments, at least one of the adhesive layer and the conductive adhesive layer is a black adhesive layer. In this way, the black adhesive layer can prevent light leakage of the display panel from causing different colors, and easily form an integrated black effect with the display panel.

An electronic device includes the display module in any of the above embodiments.

For the above electronic equipment, the composite layer has a good electromagnetic shielding effect and can realize EMI protection, and the thickness range of each layer structure in the composite layer can be set so that the ultrasonic sensor can collect the clear ultrasonic signal reflected back and generate a clear fingerprint image , Meet fingerprint imaging, realize fingerprint unlock function.

Description of the drawings

Through a more detailed description of the preferred embodiments of the present application shown in the drawings, the above and other objectives, features and advantages of the present application will become clearer. In all the drawings, the same reference numerals indicate the same parts, and the drawings are not drawn on the scale of the actual size deliberately, and the focus is to show the gist of the present application.

FIG. 1 is a schematic structural diagram of an electronic device provided by an embodiment of the application.

FIG. 2 is a schematic structural diagram of a display module of the electronic device in FIG. 1 according to an embodiment.

FIG. 3 is a schematic structural diagram of a display module of the electronic device in FIG. 1 according to another embodiment.

Detailed ways

In order to make the above objectives, features, and advantages of the present application more obvious and understandable, the specific implementation manners of the present application will be described in detail below with reference to the accompanying drawings. In the following description, many specific details are set forth in order to fully understand this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of this application. Therefore, this application is not limited by the specific implementation disclosed below.

It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or a central element may also be present. When an element is considered to be "connected" to another element, it can be directly connected to the other element or an intermediate element may be present at the same time.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of this application. The terms used in the specification of the application herein are only for the purpose of describing specific embodiments, and are not intended to limit the application. The term "and/or" as used herein includes any and all combinations of one or more related listed items.

Referring to FIG. 1, this application will take a smart phone as an example to describe the electronic device 10. Those skilled in the art can easily understand that the electronic device 10 of the present application can be any device with communication and storage functions, such as a smart phone, a tablet computer, a notebook computer, a portable phone, a video phone, a digital still camera, an e-book reader, The presentation form of the electronic device 10 such as a portable multimedia player (PMP), a mobile medical device, and other smart terminals is not limited in any way. Of course, for wearable devices such as smart watches, it is also applicable to the electronic device 10 of each embodiment of the present application.

In one embodiment, the electronic device 10 includes a middle casing 11, a back cover 12, and a display screen assembly 13. The back cover 12 and the display screen assembly 13 are connected to opposite sides of the middle casing 11 and enclosed to form a receiving space. It can be used to install the motherboard, power supply and other components of the electronic device 10. The side of the display screen assembly 13 away from the back cover 12 includes a displayable area 131. The displayable area 131 can constitute all or part of the side of the display screen assembly 13 away from the back cover 12, and the displayable area 131 is used for image information display. It should be noted that the display assembly 13 and the middle casing 11 can form a display module 1000. In other embodiments, the middle shell 11 may be omitted.

Referring to FIG. 2, in an embodiment, the display module 1000 includes a display panel 100, an ultrasonic sensor 200 and a composite layer 300. The display panel 100 includes a first surface 110 and a second surface 120 arranged oppositely. The display panel 100 may adopt an LCD (Liquid Crystal Display) screen for displaying information, and the LCD screen may be a TFT (Thin Film Transistor). Screen or IPS (In-Plane Switching) screen or SLCD (Splice Liquid Crystal Display) screen. In another embodiment, the display panel 100 may use an OLED (Organic Light-Emitting Diode, organic electro-laser display) screen for displaying information, and the OLED screen may be an AMOLED (Active Matrix Organic Light-Emitting Diode, active matrix organic light emitting diode). Polar body) screen or Super AMOLED (Super Active Matrix Organic Light Emitting Diode) screen or Super AMOLED Plus (Super Active Matrix Organic Light Emitting Diode Plus, magic screen) screen, not here Repeat it again.

The ultrasonic sensor 200 is disposed on the side of the second surface 120 away from the first surface 110, that is, the ultrasonic sensor 200 is installed in the electronic device 10 and located below the display panel 100 in the drawing shown in FIG. 2. Specifically, in the process of manufacturing the electronic device 10 of the present application, the ultrasonic sensor 200 may be manufactured first, and after the manufacturing of the ultrasonic sensor 200 is completed, the ultrasonic sensor 200 can be directly attached to the bottom of the display panel 100.

The ultrasonic sensor 200 can scan a user's fingerprint using ultrasonic waves and recognize the fingerprint. Taking the embodiment shown in FIG. 2 as an example, the top surface of the ultrasonic sensor 200 faces the display panel 100, and the ultrasonic sensor 200 can transmit ultrasonic waves penetrating the display panel 100 and receive ultrasonic waves reflected by a user’s finger touching the first surface 110. At the same time, the reflected ultrasonic waves are converted into electrical signals. Wherein, the top surface of the ultrasonic sensor is shown in FIG. 2 as the surface where the ultrasonic sensor 200 and the second surface 120 are attached. Since the display panel 100 can conduct ultrasonic waves, when a user touches a position on the outer surface of the display panel 100 (ie, the first surface 110) opposite to the ultrasonic sensor 200, the ultrasonic waves emitted by the ultrasonic sensor 200 are transmitted to the user through the display panel 100 The reflected ultrasonic waves can be generated by the fingers of, and then the ultrasonic sensor 200 receives the reflected ultrasonic waves and converts the reflected ultrasonic waves into electrical signals. The ultrasonic sensor 200 can generate the collected fingerprint images based on these electrical signals and perform fingerprint recognition.

In the above-mentioned electronic device 10, when the user's finger touches the display panel 100, the ultrasonic wave emitted by the ultrasonic sensor 200 passes through the display panel 100 to produce reflection, and the ultrasonic sensor 200 can perform fingerprint recognition based on the reflected ultrasonic wave, and realize Fingerprint recognition under the screen. Since the ultrasonic sensor 200 does not need to be arranged in the frame of the electronic device 10, the area of the visible area of the electronic device 10 is increased.

Although the ultrasonic sensor 200 can realize fingerprint recognition under the screen, since the ultrasonic sensor 200 emits ultrasonic waves under high-frequency and high-pressure conditions, it is extremely easy to generate a large number of electromagnetic waves and become a radiation interference source. If EMI protection is not performed on the ultrasonic sensor 200, the performance of the ultrasonic sensor 200 may be easily affected. For example, the signal strength of the ultrasonic sensor 200 (such as the signal-to-noise ratio (SNR) value) may be reduced, and noise may be generated. In addition, the electromagnetic waves radiated by the ultrasonic sensor 200 will affect the operation of other electronic components. For example, it may affect the lighting process of the display panel 100 and cause signal interference and color difference.

Based on this, the present application provides a composite layer 300 between the display panel 100 and the ultrasonic sensor 200 to realize EMI shielding and protection and improve the quality of fingerprint images collected by the ultrasonic sensor 200.

The composite layer 300 includes an adhesive layer 310, an electromagnetic shielding layer 320, and a conductive adhesive layer 330 that are laminated and adhered in sequence. The adhesive layer 310 is attached to the second surface 120, and the adhesive layer 310 may be a double-sided adhesive such as acrylic adhesive. The electromagnetic shielding layer 320 is used for shielding signals, and the electromagnetic shielding layer 320 does not reduce the transmission of ultrasonic signals. The electromagnetic shielding layer 320 may be a metal foil layer, such as a copper foil layer. The conductive adhesive layer 330 is attached to the ultrasonic sensor 200, and the conductive adhesive layer 330 is grounded so that the electromagnetic shielding layer 320 can shield electromagnetic signals. In an embodiment, at least one of the adhesive layer 310 and the conductive adhesive layer 330 is a black adhesive layer. In this way, the black glue layer can prevent the display panel 100 from leaking light and cause different colors, and it is easy to form an integrated black effect with the display panel 100.

The inventor uses the adhesive layer 310 and the conductive adhesive layer 330 of double-sided tape, and uses the electromagnetic shielding layer 320 as the copper foil layer. After experimental verification, the inventor finds that the thickness of each film layer in the composite layer 300 is The fingerprint image has a significant impact. In order to obtain the thickness range value of each film layer in the composite layer 300, the controlled variable method was used to test the influence of the thickness value of each film layer on the test image at room temperature. Please refer to Table 1:

Table 1 The influence of the thickness of each layer in the composite layer on the test image at a normal temperature of 25℃

It can be seen from Table 1 that, comparing experiment 2 and experiment 5, or comparing experiment 3 and experiment 6, the thickness d2 of the electromagnetic shielding layer 320 is constant, the thickness d1 of the adhesive layer 310 and the thickness d3 of the conductive adhesive layer 330 are thinner, the SNR The larger the value, the clearer the test image. In addition, in comparison experiment 2, experiment 3 and experiment 4, or comparison experiment 5, experiment 6 and experiment 7, the thickness d1 of the adhesive layer 310 and the thickness d3 of the conductive adhesive layer 330 are constant, and the thickness d2 of the electromagnetic shielding layer 320 is thinner , The larger the SNR value, the clearer the test image. Among them, the test images of Experiment 3, Experiment 4, Experiment 6 and Experiment 7 are all clear, indicating that the thickness value of each film layer of the composite layer 300 is qualified. Based on the above experimental data and considering the lower limit of the thickness of each film layer (the smaller the film thickness, the more difficult it is to process), it can be seen that the thickness d1 of the adhesive layer 310 is about 0.003 mm to about 0.006 mm, and the thickness of the electromagnetic shielding layer 320 The value d2 is about 0.006 mm to about 0.009 mm, and the thickness value d3 of the conductive adhesive layer 330 is about 0.003 mm to about 0.006 mm. In this way, the ultrasonic sensor 200 can collect the reflected clear ultrasonic signal and generate a clear fingerprint image.

Taking the electronic device 10 as a mobile phone as an example, the working temperature of the ultrasonic sensor 200 will reach about 40°C-50°C due to the heat generated by the mobile phone during continuous operation. The acoustic impedance and Young's modulus of the mobile phone material will change with temperature. The change will affect the ultrasonic signal transmission, so the inventor continued to test the influence of each film thickness on the test image in Experiment 3, Experiment 4, Experiment 6, Experiment 7 and the newly added Experiment 8 at 55°C.

Table 2 The influence of the thickness of each layer in the composite layer on the test image at 55℃

It can be seen from Table 2 that when the temperature rises to 55°C, the SNR value and image clarity both decrease. Among them, in Experiments 3 and 4, when the thickness d1 of the adhesive layer 310 and the thickness of the conductive adhesive layer 330 are When the thickness d3 is 0.006mm, the test image appears blurred. In Experiment 6 and Experiment 7, when the thickness d1 of the adhesive layer 310 and the thickness d3 of the conductive adhesive layer 330 are 0.003 mm, the test image still appears clear. In Experiment 8, when the thickness d1 of the glue layer 310 and the thickness d3 of the conductive glue layer 330 are 0.004 mm, the test image still appears clear. Therefore, the thickness d1 of the adhesive layer 310 and the thickness d3 of the conductive adhesive layer 330 are further limited to about 0.003 mm to about 0.004 mm, and the thickness d2 of the electromagnetic shielding layer 320 is limited to about 0.006 mm to about 0.009 mm, which still meets the requirements of use. . The thickness of each film layer within this range can meet the high temperature operation requirements of the electronic device 10. In a specific embodiment, the thickness d1 of the adhesive layer 310 and the thickness d3 of the conductive adhesive layer 330 may be selected to be 0.003 mm, and the thickness d2 of the electromagnetic shielding layer 320 may be 0.006 mm.

In an embodiment, the bonding adhesive layer 310 and the conductive adhesive layer 330 may use conventional double-sided adhesives and add copper powder, nickel powder, and carbon powder. The inventor found that the particle size of copper powder, nickel powder and carbon powder has a greater impact on the fingerprint test image. The inventor has done the following experimental verification, please refer to Table III:

Table 3 The influence of the particle size of each element on the fingerprint test image

实验序号Experiment number	铜粉粒径/mmCopper powder particle size/mm	镍粉粒径/mmNickel powder particle size/mm	碳粉粒径/mmToner particle size/mm	测试影像Test image
99	<0.008mm<0.008mm	<0.008mm<0.008mm	<0.005mm<0.005mm	有黑点 Black spots
1010	<0.003mm<0.003mm	<0.003mm<0.003mm	<0.001mm<0.001mm	有黑点 Black spots
1111	<0.001mm<0.001mm	<0.001mm<0.001mm	<0.001mm<0.001mm	无黑点No black spots

It can be seen from Table 3 that the particle size of copper powder, nickel powder and carbon powder within 0.001mm can meet the requirements of use. On the one hand, copper powder, nickel powder and carbon powder can further improve the conductivity of each film layer. However, if the particle size of copper powder, nickel powder and carbon powder is too large, the surface roughness of each film layer will be larger. Conducive to imaging and easy to produce black spots. It can be seen from this that at least one of the adhesive layer 310 and the conductive adhesive layer 330 includes components with the following particle sizes: copper powder from about 0 mm to about 0.001 mm, nickel powder from about 0 mm to about 0.001 mm, and from about 0 mm to about 0.001 mm. About 0.001mm of toner. If the particle size of copper powder, nickel powder and carbon powder is too small, it will be more difficult to process and not easy to save costs. Therefore, in one embodiment, the particle size of copper powder, nickel powder and carbon powder are all controlled to about 0.0005 mm to about 0.001mm.

In one embodiment, please continue to refer to FIG. 2, the display module 1000 further includes a circuit board 400 electrically connected to the ultrasonic sensor 200. It should be noted that the technical feature of the circuit board 400 can be applied to other embodiments. The circuit board 400 is placed outside the path through which the ultrasonic wave is transmitted to the outer surface (first surface 110) of the display panel 100, that is, the ultrasonic wave will not pass through the circuit board 400 when it is transmitted to the contact object, so that the circuit board 400 can be prevented from contacting the circuit board 400. The influence caused by the conduction of ultrasonic waves.

In addition, a driver chip is provided on the circuit board 400, and the driver chip is, for example, an ASIC (Application Specific Integrated Circuit) chip. The driving chip provides a control signal to the ultrasonic sensor 200, for example, sends a high-frequency electrical signal to the ultrasonic sensor 200, so that the ultrasonic sensor 200 emits ultrasonic waves. In addition, the driving chip also receives the electrical signal obtained by the ultrasonic sensor 200 converting the reflected ultrasonic wave, so as to identify the fingerprint. It can be understood that the arrangement of the driving chip is not limited to the above situation, for example, the driving chip may also be directly installed in the ultrasonic sensor 200.

In an embodiment, the ultrasonic sensor 200 includes a TFT substrate 210, a piezoelectric layer 220, and an electrode layer 230. The TFT substrate 210 is attached to the conductive adhesive layer 330, and the piezoelectric layer 220 is provided between the TFT substrate 210 and the electrode layer 230 and is used for transmitting and receiving ultrasonic waves. Based on the characteristics of the respective materials of the TFT substrate 210, the electrode layer 230, and the piezoelectric layer 220, by bonding the TFT substrate 210 to the display panel 100 so that the entire ultrasonic sensor 200 is located at the bottom of the display panel 100, the stability of bonding can be improved. And easy to fit.

It should be noted that the TFT substrate 210 includes a substrate, a plurality of thin film transistors arranged on the substrate in an array manner, and a circuit provided on the substrate for connecting the thin film transistors. In addition, the TFT substrate 210 can perform processing such as amplifying the electrical signal. Specifically, the TFT substrate 210 may use a thin film as the substrate to meet the flexibility requirements of the entire electronic device 10 (for example, the display panel 100 is a flexible panel). The piezoelectric layer 220 is composed of a piezoelectric material, and the piezoelectric material 220 is, for example, a ferroelectric polymer P (VDF-TrFE). The electrode layer 230 is made of a conductive material, and the conductive material may be, for example, silver paste.

Both the TFT substrate 210 and the electrode layer 230 are electrically connected to the above-mentioned driving chip. Taking the driving chip on the circuit board as an example 400, the mounting position of the circuit board 400 cannot be at least above the piezoelectric layer 220. For example, taking the example shown in FIG. 2 as an example, the circuit board 400 may be placed on one side of the electrode layer 230 and the piezoelectric layer 220, and electrically connected to the TFT substrate 210 and the electrode layer 230, respectively. Avoid the interference to the ultrasonic conduction.

The working principle of the above-mentioned ultrasonic sensor 200 is: the drive chip applies a corresponding high-frequency electric signal to the electrode layer 230, and after the high-frequency electric signal is applied to the electrode layer 230, the electrode layer 230 conducts the high-frequency electric signal to the piezoelectric layer 220 , So that the piezoelectric layer 220 emits ultrasonic waves. The ultrasonic wave propagates upwards until it reaches the outer surface of the display panel 100 and is reflected after touching the user's finger. After that, the piezoelectric layer 220 receives the reflected ultrasonic wave and converts it into an electrical signal, which is then processed (for example, amplified) by the TFT substrate 210. Then it is transferred to the driver chip and converted into an image to identify the fingerprint.

In one embodiment, the ultrasonic sensor further includes a protective layer 240, which is connected to the side of the electrode layer 230 away from the piezoelectric layer 220, and the protective layer 240 is used to direct the ultrasonic waves emitted by the piezoelectric layer 220 toward the display panel 100. Side reflection. The protective layer 240 may also be used for EMI (Electromagnetic Interference, electromagnetic interference) protection. For example, the protective layer 240 may be a protective ink. Therefore, by providing the protective layer 240, the fingerprint recognition accuracy of the external signal image ultrasonic sensor 200 can be avoided.

In an embodiment, the display module 1000 further includes a protective cover 500, and the protective cover 500 is connected to the first surface 110 of the display panel 100. The protective cover 500 may be, for example, a glass cover or a plastic cover. The protective cover 500 can protect the display panel 100 from external interference and enhance the structural strength of the display panel 100.

In one embodiment, the display module 1000 further includes a light-shielding buffer layer 600, and the light-shielding buffer layer 600 is attached to the second surface 120 around the composite layer 300. The light-shielding buffer layer 600 may be black foam, and the black foam can well absorb the light emitted to the display panel 100 under the screen, so as to form a good protection for the display panel 100. The black foam is bonded to the display panel 100, so that the black foam can be well fixed. In addition, black foam is used as the light-shielding buffer layer 600. Since the cost of black foam is not high, the cost of the electronic device 10 can be saved as a whole. In addition, the black foam can also play a good buffering effect. When the display module 1000 is impacted or a sudden external force is applied, the foam can protect the ultrasonic sensor 300, so that the ultrasonic sensor 300 is not easily damaged, that is, it ensures that the display module 1000 is not easily damaged. The service life of group 1000.

In an embodiment, the display module 1000 further includes a heat dissipation layer 700, and the heat dissipation layer 700 surrounds the composite layer 300 and is disposed on a side of the light shielding buffer layer 600 away from the second surface 120. The heat dissipation layer 700 may include, for example, a single-layer or multi-layer heat dissipation structure formed of at least one of graphite, metallic copper, PET, and the like.

In order to facilitate the grounding of the conductive adhesive layer 330, in one embodiment, referring to FIG. 2, the display module 1000 further includes a conductive member 800. The conductive member 800 may be, for example, a conductive cloth or a metal tape (such as a copper foil tape). The conductive adhesive layer 330 is connected to the circuit board 400 through the conductive member 800, and specifically may be connected to the ground wire of the bare copper area of the circuit board 400, so as to realize the grounding of the conductive adhesive layer 330 through the circuit board 400. Of course, in other embodiments (not shown), the conductive adhesive layer 330 may also be connected to the bare copper area ground of the display panel 100 through the conductive member 800, so as to realize the grounding of the conductive adhesive layer 330. In order to facilitate the grounding of the conductive adhesive layer 330. In one embodiment, referring to FIG. 3, the display assembly 13 and the middle casing 11 form a display module 1000, and the middle casing 13 and the heat dissipation layer 700 are connected to the side away from the display panel 100. At this time, the conductive adhesive layer 330 can pass through The conductive member 800 is connected to the middle shell 11 to realize the grounding of the conductive adhesive layer 330 through the middle shell 11.

The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the various technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, All should be considered as the scope of this specification.

The above-mentioned embodiments only express several implementation manners of the present application, and their description is relatively specific and detailed, but they should not be interpreted as a limitation on the scope of the patent application. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can be made, and these all fall within the protection scope of this application. Therefore, the scope of protection of the patent of this application shall be subject to the appended claims.

Claims

A display module includes:

The display panel includes a first surface and a second surface that are oppositely arranged;

An ultrasonic sensor arranged on a side of the second surface away from the first surface, the ultrasonic sensor can emit ultrasonic waves that penetrate the display panel and receive reflected ultrasonic waves; and

The composite layer is arranged between the display panel and the ultrasonic sensor. The composite layer includes an adhesive layer, an electromagnetic shielding layer and a conductive adhesive layer that are laminated and laminated in sequence, and the adhesive layer is attached to the On the second surface, the conductive adhesive layer is attached to the ultrasonic sensor, and the conductive adhesive layer is grounded; wherein the thickness of the adhesive layer is about 0.003 mm to about 0.006 mm, and the electromagnetic shield The thickness of the layer is about 0.006 mm to about 0.009 mm, and the thickness of the conductive adhesive layer is about 0.003 mm to about 0.006 mm.
4. The display module of claim 1, wherein the adhesive layer has a thickness of about 0.003 mm to about 0.004 mm, and the conductive adhesive layer has a thickness of about 0.003 mm to about 0.004 mm.
The display module of claim 1, further comprising a light-shielding buffer layer, the light-shielding buffer layer being attached to the second surface around the composite layer.
3. The display module according to claim 3, further comprising a heat dissipation layer, the heat dissipation layer is disposed on a side of the light-shielding buffer layer away from the second surface surrounding the composite layer.
The display module according to claim 4, wherein the display module comprises a middle shell and a conductive member, the middle shell is connected to a side of the heat dissipation layer away from the display panel, and the conductive adhesive layer passes through the The conductive member is connected with the middle shell, so as to realize the grounding of the conductive adhesive layer through the middle shell.
The display module according to claim 1, wherein the display module comprises a circuit board and a conductive member, the circuit board is electrically connected to the ultrasonic sensor, and the conductive adhesive layer is connected to the conductive member through the conductive member. The circuit board is connected to realize the grounding of the conductive adhesive layer through the circuit board.
The display module according to claim 1, wherein at least one of the adhesive layer and the conductive adhesive layer comprises copper powder with a particle diameter of about 0 mm to about 0.001 mm, and a particle diameter of about 0 mm to about 0.001 mm. 0.001mm nickel powder, carbon powder with a particle size of about 0mm to about 0.001mm.
8. The display module of claim 7, wherein in the adhesive layer or the conductive adhesive layer, the copper powder has a particle size of about 0.0005 mm to about 0.001 mm, and the nickel powder has a particle size of about 0.0005 mm to about 0.001 mm. It is about 0.0005 mm to about 0.001 mm, and the particle size of the carbon powder is about 0.0005 mm to about 0.0001 mm.
The display module according to claim 1, wherein the ultrasonic sensor comprises a thin film transistor (TFT) substrate, a piezoelectric layer and an electrode layer, the TFT substrate is attached to the conductive adhesive layer, and the piezoelectric layer is provided with Between the TFT substrate and the electrode layer and used for transmitting and receiving ultrasonic waves.
9. The display module according to claim 9, wherein the ultrasonic sensor further comprises a protective layer, and the protective layer is connected to a side of the electrode layer away from the piezoelectric layer.
The display module according to claim 9, wherein the TFT substrate comprises a substrate, a plurality of thin film transistors arranged in an array on the substrate, and a circuit for connecting the thin film transistors on the substrate .
The display module according to claim 1, wherein the display module further comprises a protective cover plate, and the protective cover plate is connected to the first surface.
The display module according to claim 1, wherein the electromagnetic shielding layer is a metal foil layer.
4. The display module of claim 1, wherein at least one of the adhesive layer and the conductive adhesive layer is a black adhesive layer.
An electronic device comprising the display module according to any one of claims 1-14.