Bonding structure of ultrasonic fingerprint module, display apparatus, and electronic device

Abstract

Disclosed in embodiments of the present application are a bonding structure of an ultrasonic fingerprint module, a display apparatus, and an electronic device. The thickness of the bonding structure is less than or equal to 15 μm, the bonding structure comprises an adhesive layer, and the acoustic impedance of the adhesive layer is less than 5 Mrayl. The effects of bonding and light blocking can be achieved, the composition of the bonding structure is simplified, and the cost is reduced.

Description

Ultrasonic fingerprint module bonding structure, display device and electronic device Technical Field

[0001] The present application relates to the field of fingerprint recognition technology, and more specifically, to an ultrasonic fingerprint module bonding structure, a display device, and an electronic device. Background Art

[0002] When attaching the ultrasonic fingerprint module to the under-display, the adhesive material has high requirements. First, the adhesive cannot be porous, as the ultrasonic waves in the operating frequency band of ultrasonic fingerprint sensors cannot penetrate air. Second, the adhesive material must be highly uniform at the microscopic level and free of defects (generally below the micrometer level).

[0003] Furthermore, since the foam layer on the screen corresponding to the ultrasonic fingerprint module has been removed through a window, an optical layer is required to ensure a good appearance. Typically, an optical layer is implemented using a layer of high-acoustic-impedance metal, such as copper, aluminum, or molybdenum. However, to ensure good ultrasonic penetration, this metal layer needs to be extremely thin (micrometer level), which places high demands on the adhesive layer used to bond the module, and this also increases the cost. Technical issues

[0004] The embodiments of the present application provide an ultrasonic fingerprint module bonding structure, a display device, and an electronic device. The ultrasonic fingerprint recognition structure adopts a low acoustic impedance material and controls the total thickness to not exceed 15 μm, thereby solving the problem of high processing technology requirements and high cost of the existing bonding structure with a metal layer. Technical Solutions

[0005] To this end, the embodiments of the present application provide the following technical solutions:

[0006] The first aspect of the present application discloses an ultrasonic fingerprint module bonding structure, wherein the bonding structure has a thickness less than or equal to 15 μm and comprises a bonding layer,

[0007] The acoustic impedance of the adhesive layer is less than 5 Mrayl.

[0008] Furthermore, the adhesive layer includes a first layer and a second layer, and the adhesive structure further includes a substrate layer, and the substrate layer is disposed between the first layer and the second layer.

[0009] The acoustic impedance of the substrate layer is less than 5 Mrayl.

[0010] Furthermore, light absorbing material is mixed in the adhesive layer.

[0011] The second aspect of the present application discloses a display device, comprising a display module and a fingerprint recognition module, wherein the fingerprint recognition module is attached to the display module via an adhesive structure, wherein the thickness of the adhesive structure is less than or equal to 15 μm.

[0012] The bonding structure includes a bonding layer, the area of ​​the bonding layer is greater than or equal to the fingerprint recognition module, and the acoustic impedance of the bonding layer is less than 5 Mrayl.

[0013] Furthermore, the adhesive layer includes a first layer and a second layer, and the adhesive structure further includes a substrate layer, the substrate layer is arranged between the first layer and the second layer, the first layer is bonded to the display module, and the second layer is bonded to the fingerprint recognition module.

[0014] The acoustic impedance of the substrate layer is less than 5 Mrayl.

[0015] Furthermore, light absorbing material is mixed in the adhesive layer.

[0016] Furthermore, the display module includes a screen, a copper foil layer is provided on the screen, and the copper foil layer is adhered to the screen by adhesive.

[0017] A window is opened on the copper foil layer and the adhesive, and the fingerprint recognition module is arranged in the window and adhered to the screen through the adhesive structure.

[0018] Furthermore, the display module includes a screen, and the screen is provided with a first layer, a base material layer and a copper foil layer.

[0019] A window is opened on the copper foil layer, and the fingerprint recognition module is arranged in the window and adhered to the base material layer of the screen through the second layer.

[0020] Furthermore, the display module includes a screen, the screen is a folding screen, a reinforcement layer is provided on the screen, and the adhesive structure is adhered to the reinforcement layer.

[0021] Furthermore, a flat layer is provided on the reinforcing layer, and the bonding structure is bonded to the flat layer.

[0022] A third aspect of the present application discloses an electronic device, comprising the above-mentioned display device.

[0023] A fourth aspect of the present application discloses an electronic device, comprising a cover plate and a fingerprint recognition module, wherein the fingerprint recognition module is adhered to the cover plate via the ultrasonic fingerprint module bonding structure.

[0024] Furthermore, a flat layer is provided on the cover plate, and the ultrasonic fingerprint module bonding structure is bonded to the flat layer. Beneficial effects

[0025] The beneficial effects of this application are:

[0026] The present application adopts a low acoustic impedance bonding structure with a thickness of less than 15 μm and an acoustic impedance of less than 5 Mrayl, so that it does not require a metal layer to ensure good ultrasonic fingerprint performance, simplifies the composition of the bonding structure, and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of each embodiment. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings in the specific description below of the present application without any creative work.

[0028] FIG1 is a schematic structural diagram of an ultrasonic fingerprint module bonding structure according to an embodiment of the present application;

[0029] FIG2 is a schematic structural diagram of an ultrasonic fingerprint module bonding structure according to an embodiment of the present application;

[0030] FIG3 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0031] FIG4 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0032] FIG5 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0033] FIG6 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0034] FIG7 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0035] FIG8 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0036] FIG9 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0037] FIG10 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0038] FIG11 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0039] FIG12 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0040] FIG13 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present application;

[0041] FIG14 shows a comparison of the performance simulation of an OLED screen using the bonding structure of the present application and using copper foil adhesive;

[0042] FIG15 shows the measured performance results of OLED screens using the bonding structure of the present application and copper foil adhesive.

[0043] In the figure,

[0044] 1. Adhesive layer; 11. First layer; 12. Second layer; 13. Base material layer; 2. Screen; 21. Adhesive; 22. Copper foil layer; 2', Folding screen body; 23. Reinforcement layer; 24. Flat layer; 3. Fingerprint recognition module; 4. Cover plate.

[0045] Implementation Methods of the Application

[0046] The following, in conjunction with the accompanying drawings, clearly and completely describes the technical solutions of the ultrasonic fingerprint module bonding structure, display device, and electronic device provided by this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts are within the scope of protection of this application.

[0047] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", and "third" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0048] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0049] In this application, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described in this application as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is given to enable any person skilled in the art to implement and use the present application. In the following description, the present application lists details for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can be implemented even without using these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present application with unnecessary details. Therefore, the present application is not intended to be limited to the embodiments shown, but should be consistent with the widest scope consistent with the principles and features disclosed in this application.

[0050] According to the first aspect of the present application, an ultrasonic fingerprint module bonding structure is provided. In some embodiments, the total thickness of the ultrasonic fingerprint module bonding structure is less than or equal to 15 μm, and the material of each part of the bonding structure is a material with low acoustic impedance, and the acoustic impedance is less than 5 Mrayl. As shown in Figure 1, the bonding structure includes at least an adhesive layer 1, and the adhesive layer 1 includes but is not limited to a pressure-sensitive adhesive or a thermosetting epoxy resin, and its acoustic impedance is less than 5 Mrayl. In this embodiment, a bonding structure with a small thickness and low acoustic impedance is used, so that the ultrasonic fingerprint performance of the bonding structure can be close to the performance of the bonding structure with a metal layer, which simplifies the composition of the bonding structure and reduces the cost.

[0051] In some embodiments, as shown in FIG2 , the adhesive structure further includes a substrate layer 13. The adhesive layer 1 includes a first layer 11 and a second layer 12. The substrate layer 13 is disposed between the first layer 11 and the second layer 12. The substrate layer 13 can provide support for the adhesive layer 1, making it easier to control the overall thickness of the adhesive structure and preventing adhesive overflow. Optionally, the substrate layer 13 is a low-impedance polymer material with an acoustic impedance of less than 5 Mrayl, including PET (Polyethylene terephthalate), PE (Polyethylene), PI (Polyimide), etc.

[0052] Optionally, a light-absorbing material may be mixed into the adhesive layer 1 to improve the light-blocking effect. The light-absorbing material includes, but is not limited to, carbon powder, black ink, etc. Furthermore, a light-absorbing material may be mixed into the first layer 11 or the second layer 12, or both the first layer 11 and the second layer 12.

[0053] According to the second aspect of the present application, a display device is provided, as shown in Figures 3 and 4, comprising a display module and a fingerprint recognition module 3. Optionally, the fingerprint recognition module 3 comprises an ultrasonic fingerprint recognition chip, and the fingerprint recognition module 3 is adhered to the display module via an adhesive structure. The adhesive structure comprises an adhesive layer 1, the area of ​​the adhesive layer 1 is greater than or equal to the fingerprint recognition module 3, the adhesive layer 1 comprises a pressure-sensitive adhesive or epoxy resin, etc., the thickness of the adhesive layer 1 is less than or equal to 15μm, and the acoustic impedance of the adhesive layer 1 is less than 5Mrayl. The adhesive structure is the same structure as the above-mentioned ultrasonic fingerprint module adhesive structure, and the specific composition and parameters are the same, and will not be described in detail here.

[0054] In some embodiments, the display module includes a screen 2, optionally an OLED (Organic Light-Emitting Diode) screen. A copper foil layer 22 is provided on the underside of screen 2 and adhered to screen 2 via adhesive 21. Adhesive 21 is optionally double-sided foam adhesive. Within the area corresponding to the fingerprint recognition zone, a window is opened in copper foil layer 22 and adhesive 21 to expose screen 2. The fingerprint recognition module 3 is adhered to screen 2 via an adhesive structure. Optionally, the adhesive structure may include only adhesive layer 1, or both adhesive layer 1 and substrate layer 13.

[0055] In some embodiments, the bonding structure includes an adhesive layer 1 and a substrate layer 13. The adhesive layer 1 includes a first layer 11 and a second layer 12. The substrate layer 13 is disposed between the first layer 11 and the second layer 12. The first layer 11 is bonded to the screen 2, and the second layer 12 is bonded to the fingerprint recognition module 3. The substrate layer 13 can provide support for the adhesive layer 1, making it easier to control the overall thickness of the bonding structure and preventing glue overflow. In this embodiment, as shown in FIG5 , the area of ​​the first layer 11 and the substrate layer 13 is the same as the area of ​​the screen 2. The first layer 11 and the substrate layer 13 are integrated with the screen 2. The copper foil layer 22 is bonded to the substrate layer 13 by adhesive 21. A window is opened on the copper foil layer 22 corresponding to the position of the fingerprint recognition module 3. The fingerprint recognition module 3 is bonded to the substrate layer 13 by the second layer 12. In another embodiment, the first layer 11, substrate layer 13, and copper foil layer 22 form a laminated structure of the screen 2 itself. The fingerprint recognition module 3 is directly bonded to the substrate layer 13 of the screen 2 via the second layer 12 by opening a window in the copper foil layer 22. This solution further reduces the thickness of the ultrasonic fingerprint 3 attached to the screen and simplifies the structure of the screen.

[0056] In some embodiments, the display module includes a foldable screen, as shown in Figures 6 and 8 . The foldable screen includes a foldable screen body 2' and a reinforcement layer 23 disposed on the underside of the foldable screen body 2'. The fingerprint recognition module 3 is bonded to the reinforcement layer 23 via an adhesive structure. Optionally, the reinforcement layer 23 is generally relatively rough, as shown in Figures 7 and 9 . Therefore, before attaching the fingerprint recognition module 3, a flattening layer 24 is first applied to the reinforcement layer 23. The adhesive structure is then bonded to the area coated with the flattening layer 24. A typical material for the flattening layer 24 is, for example, primer glue.

[0057] According to a third aspect of the present application, an electronic device is provided, including the above-mentioned display device. In some embodiments, the electronic device includes a smart phone, a tablet computer, etc.

[0058] In some embodiments, the electronic device includes a smart door lock, an attendance machine, etc., including a cover plate, and the fingerprint recognition module 3 is arranged on the cover plate 4. The cover plate 4 is made of glass, plastic, or metal. As shown in Figures 10 and 12, the fingerprint recognition module 3 is bonded to the cover plate 4 through an adhesive structure. The adhesive structure can include only an adhesive layer 1 or an adhesive layer 1 and a base material layer 13. The first layer 11 of the adhesive layer 1 is bonded to the cover plate 4, and the second layer 12 is bonded to the fingerprint recognition module 3. The roughness of the cover plate 4 is generally relatively large. As shown in Figures 11 and 13, before bonding the fingerprint recognition module 3, a flat layer 24 can be coated on the corresponding area of ​​the cover plate 4. The adhesive structure is bonded to the flat layer 24. Primer glue can be used for the flat layer 24.

[0059] The adhesive structure of the present application with three different thicknesses of 5μm, 10μm and 15μm was respectively selected and set on the OLED screen to compare the performance of the OLED screen using copper foil glue in the prior art. As shown in Figures 14 and 15, the performance of the adhesive structure of the present application is related to the thickness. When the thickness is greater, the performance is worse than that of the copper foil glue, and the smaller the thickness, the smaller the performance gap with the copper foil glue, that is, the smaller the thickness, the better the performance. As shown in Figure 15, when the thickness of the adhesive structure of the present application reaches 15μm, the high-frequency lines have already shown obvious blurring, so it is recommended that the thickness does not exceed 15μm.

[0060] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, and simple improvements made to the essential content of the present application shall be included in the scope of protection of the present application. Industrial Applicability

[0061] The ultrasonic fingerprint module bonding structure provided in this application is used to affix an ultrasonic fingerprint module to a screen or cover of an electronic device. The bonding structure uses a low-acoustic-impedance material and, by limiting the thickness of the bonding structure to no more than 15 μm, ensures that the overall performance of the bonding structure is similar to that of a bonding structure with a metal layer, meeting the functional requirements of fingerprint recognition modules and electronic devices. This solves the problem of high processing requirements and high costs associated with existing bonding structures with metal layers.

Claims

1. An ultrasonic fingerprint module bonding structure, wherein: The thickness of the bonding structure is less than or equal to 15 μm, and the bonding structure comprises a bonding layer (1), The acoustic impedance of the adhesive layer (1) is less than 5 Mrayl.

2. The ultrasonic fingerprint module bonding structure according to claim 1, wherein: The adhesive layer (1) includes a first layer (11) and a second layer (12), and the adhesive structure further includes a substrate layer (13), wherein the substrate layer (13) is arranged between the first layer (11) and the second layer (12). The acoustic impedance of the substrate layer (13) is less than 5 Mrayl.

3. An ultrasonic fingerprint module bonding structure according to claim 1 or 2, wherein: The adhesive layer (1) is mixed with light absorbing material.

4. A display device, wherein: It comprises a display module and a fingerprint recognition module (3), wherein the fingerprint recognition module (3) is adhered to the display module via an adhesive structure, wherein the thickness of the adhesive structure is less than or equal to 15 μm. The bonding structure comprises a bonding layer (1), the area of the bonding layer (1) is greater than or equal to the area of the fingerprint recognition module (3), and the acoustic impedance of the bonding layer (1) is less than 5 Mrayl.

5. A display device according to claim 4, wherein: The adhesive layer (1) comprises a first layer (11) and a second layer (12), and the adhesive structure further comprises a base material layer (13), wherein the base material layer (13) is arranged between the first layer (11) and the second layer (12), the first layer (11) is bonded to the display module, and the second layer (12) is bonded to the fingerprint recognition module (3). The acoustic impedance of the substrate layer (13) is less than 5 Mrayl.

6. A display device according to claim 4 or 5, wherein: The adhesive layer (1) is mixed with light absorbing material.

7. A display device according to claim 4 or 5, wherein: The display module comprises a screen (2), a copper foil layer (22) is provided on the screen (2), and the copper foil layer (22) is adhered to the screen (2) by adhesive (21). A window is formed on the copper foil layer (22) and the adhesive (21); the fingerprint recognition module (3) is arranged in the window and adhered to the screen (2) via the adhesive structure.

8. A display device according to claim 5, wherein: The display module comprises a screen (2), on which a first layer (11), a base material layer (13) and a copper foil layer (22) are provided. A window is opened on the copper foil layer (22), and the fingerprint recognition module (3) is arranged in the window and is bonded to the base material layer (13) of the screen (2) through the second layer (12).

9. A display device according to claim 4 or 5, wherein: The display module comprises a folding screen body (2'), a reinforcing layer (23) is provided on the folding screen body (2'), and the bonding structure is bonded to the reinforcing layer (23).

10. A display device according to claim 9, wherein: A flat layer (24) is provided on the reinforcing layer (23), and the bonding structure is bonded to the flat layer (24).

11. An electronic device, wherein: A display device comprising any one of claims 4 to 10.

12. An electronic device, wherein: It comprises a cover plate (4) and a fingerprint recognition module (3), wherein the fingerprint recognition module (3) is adhered to the cover plate (4) by the ultrasonic fingerprint module bonding structure according to any one of claims 1 to 3.

13. An electronic device according to claim 12, wherein: A flat layer (24) is provided on the cover plate (4), and the ultrasonic fingerprint module bonding structure is bonded to the flat layer (24).

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