Display module, preparation method thereof and display device

Abstract

The invention provides a display module, a preparation method thereof and a display device, and belongs to the technical field of display. The display module comprises a display panel, an ultrasonic fingerprint identification sensor located on the non-display side of the display panel, and a cover plate located on the display side of the display panel. A plurality of grooves are formed in one side, close to the display panel, of the cover plate; the cross sectional area, parallel to the reference plane, of the groove is gradually reduced in the direction away from the display panel; the orthographic projection of the groove on the reference plane is at least partially overlapped with the orthographic projection of the ultrasonic fingerprint identification sensor on the reference plane; the reference plane is a plane parallel to the display panel.

Description

Technical Field

[0001] This disclosure belongs to the field of display technology, specifically relating to a display module and its manufacturing method, and a display device. Background Technology

[0002] Fingerprints are unique, innate, and unchanging features that distinguish one person from another. They consist of a series of ridges and valleys on the surface of the skin at the fingertips, and the details of these ridges and valleys determine the uniqueness of the fingerprint pattern. Display products with fingerprint recognition capabilities have been developed for personal authentication, enhancing the information security of display products. Summary of the Invention

[0003] This disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a display module and its manufacturing method, as well as a display device.

[0004] In a first aspect, embodiments of this disclosure provide a display module, the display module comprising: a display panel, an ultrasonic fingerprint recognition sensor located on the non-display side of the display panel, and a cover plate located on the display side of the display panel;

[0005] The cover plate has multiple grooves on the side near the display panel; the cross-sectional area of ​​the grooves parallel to the reference plane gradually decreases in the direction away from the display panel;

[0006] The orthographic projection of the groove on the reference plane at least partially overlaps with the orthographic projection of the ultrasonic fingerprint sensor on the reference plane; the reference plane is a plane parallel to the display panel.

[0007] In some embodiments, the display module further includes: a filler material layer filled within the groove;

[0008] The ultrasonic refractive index of the filling material layer is greater than that of the cover plate.

[0009] In some embodiments, the display module further includes: an optical adhesive layer located on the side of the cover plate near the display panel;

[0010] The difference between the ultrasonic refractive index of the filling material layer and the ultrasonic refractive index of the optical adhesive layer is less than a threshold value.

[0011] In some embodiments, the material of the filler layer includes liquid optical adhesive.

[0012] In some embodiments, the display module further includes a support layer located between the display panel and the ultrasonic fingerprint sensor;

[0013] The support layer has an opening; the opening exposes the ultrasonic fingerprint sensor.

[0014] In some embodiments, the display module further includes a support layer located on the side of the display panel opposite to the cover plate;

[0015] The support layer has an opening; the ultrasonic fingerprint sensor is embedded in the opening.

[0016] In some embodiments, the groove has a width of 40 to 60 micrometers, a depth of 60 to 90 micrometers, and a distance of 10 to 30 micrometers between adjacent grooves.

[0017] In some embodiments, the shape of the groove includes at least one of the following: hemispherical, semi-cylindrical, frustum, frustum-cylindrical, pyramidal, and prism.

[0018] Secondly, embodiments of this disclosure provide a display device, the display device including the display module as provided in the first aspect.

[0019] Thirdly, embodiments of this disclosure provide a method for manufacturing a display module, the method comprising:

[0020] The ultrasonic fingerprint sensor is assembled on the non-display side of the display panel;

[0021] Multiple grooves are formed on one side of the cover plate using etching or micron-level imprinting processes;

[0022] The cover plate is attached to the display side of the display panel; the cross-sectional area of ​​the groove parallel to the reference plane gradually decreases in the direction away from the display panel; the orthographic projection of the groove on the reference plane at least partially overlaps with the orthographic projection of the ultrasonic fingerprint sensor on the reference plane; the reference plane is a plane parallel to the display panel. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of an exemplary display module.

[0024] Figure 2 This is a schematic diagram of the structure of a display module provided in an embodiment of this disclosure.

[0025] Figure 3 This is a schematic diagram of an ultrasonic wave propagation path.

[0026] Figure 4 This is a schematic diagram of another ultrasonic wave propagation path.

[0027] Figure 5 This is a schematic diagram of another display module provided in an embodiment of the present disclosure.

[0028] Figure 6 This is a schematic flowchart illustrating a method for manufacturing a display module according to an embodiment of the present disclosure. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. The components of the embodiments of this disclosure described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this disclosure provided in the accompanying drawings is not intended to limit the scope of the claimed disclosure, but merely represents selected embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure. Without conflict, the various embodiments of this disclosure and the features in the embodiments can be combined with each other.

[0030] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising,” “including,” or “including,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0031] In this disclosure, "multiple or several" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0032] Currently, mature fingerprint recognition technologies mainly include ultrasonic fingerprint recognition and optical fingerprint recognition. Ultrasonic fingerprint recognition constructs a three-dimensional fingerprint image by emitting ultrasonic waves and receiving their reflected signals, capturing three-dimensional features such as fingerprint ridges and pores. Since forging fingerprints with three-dimensional features is extremely difficult, this acquisition of depth information significantly improves security. Furthermore, ultrasonic fingerprint recognition has low dependence on finger condition, working stably even with wet, dirty, or oily hands, greatly enhancing ease of use. It is also unaffected by screen aging or screen protectors, maintaining a high recognition rate in various environments. Simultaneously, ultrasonic waves can penetrate the epidermis for deep scanning, not failing due to peeling or minor finger damage, ensuring reliable recognition in all situations. In addition, ultrasonic fingerprint recognition offers rapid response, a smooth and seamless unlocking process, and no strong light stimulation, resulting in a more comfortable user experience. It also offers greater flexibility in hardware design, eliminating the need to reserve a specific location for the ultrasonic fingerprint sensor, which is beneficial for optimizing the internal space layout of the display module.

[0033] Figure 1 This is a schematic diagram of an exemplary display module, such as... Figure 1 As shown, the display module includes: a display panel 101, an ultrasonic fingerprint sensor 102 located on the non-display side of the display panel 101, and a cover plate 103 located on the display side of the display panel 101; the display module also includes: an optical adhesive layer 104 located on the side of the cover plate 103 near the display panel 101, and a polarizer 105 bonded to the cover plate 103 by the optical adhesive layer 104.

[0034] Depend on Figure 1 As can be seen, in existing display modules, such as OLED display modules widely used in mobile phones, the structure is usually composed of multiple layers of different materials stacked together, and the acoustic impedance characteristics of each layer are different. This causes ultrasonic waves to be reflected and refracted at the interfaces between different materials during propagation. This multiple interface effect caused by acoustic impedance mismatch significantly weakens the propagation energy of ultrasonic waves and causes the ultrasonic wave path to deviate, thereby reducing the quality of the final received signal and directly affecting the imaging accuracy and recognition reliability of ultrasonic fingerprint recognition sensors.

[0035] To at least solve one of the aforementioned technical problems, this disclosure provides a display module, its manufacturing method, and a display device. The display module, its manufacturing method, and the display device provided in this disclosure will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0036] In a first aspect, embodiments of this disclosure provide a display module. Figure 2 This is a schematic diagram of the structure of a display module provided in an embodiment of the present disclosure, such as... Figure 2As shown, the display module includes: a display panel 101, an ultrasonic fingerprint sensor 102 located on the non-display side of the display panel 101, and a cover plate 103 located on the display side of the display panel 101; the cover plate 103 has a plurality of grooves 1031 on the side near the display panel 101; the cross-sectional area of ​​the grooves 1031 parallel to the reference plane gradually decreases along the direction away from the display panel 101; the orthographic projection of the grooves 1031 on the reference plane at least partially overlaps with the orthographic projection of the ultrasonic fingerprint sensor 102 on the reference plane; the reference plane is a plane parallel to the display panel 101.

[0037] The display panel 101 integrates multiple pixel units arranged in an array. Each pixel unit can be independently driven to emit light, eliminating the need for additional structures such as backlight modules found in traditional LCD displays. This allows the display panel 101 to achieve a significantly thinner and lighter physical structure, while also possessing excellent flexibility. Structurally, each pixel unit typically includes a pixel driving circuit and a light-emitting device electrically connected to it. The pixel driving circuit generates a corresponding driving current or voltage based on the input signal, thereby controlling the light-emitting device to emit light under predetermined driving conditions, thus achieving precise image display.

[0038] For example, the pixel driving circuit can be a 2T1C (i.e., 2 transistors and 1 capacitor) structure, a 3T1C (i.e., 3 transistors and 1 capacitor) structure, a 4T2C (i.e., 4 transistors and 2 capacitors) structure, a 5T1C (i.e., 5 transistors and 1 capacitor) structure, a 7T1C (7 transistors and 1 storage capacitor) structure, an 8T1C (i.e., 8 transistors and 1 capacitor) structure, an 8T2C (i.e., 8 transistors and 2 capacitors) structure, or a 10T1C (i.e., 10 transistors and 1 capacitor) structure, etc.

[0039] Light-emitting devices may include, but are not limited to, organic light-emitting diodes (OLEDs), quantum dot light-emitting diodes (QLEDs), or micro light-emitting diodes (Micro LEDs).

[0040] The ultrasonic fingerprint sensor 102 can be integrated into the backlight side of the display panel 101, achieving a seamless physical presence while completing the entire process from ultrasonic signal emission and echo acquisition to preliminary data processing. Specifically, the ultrasonic fingerprint sensor 102 is a micro-electro-mechanical system (MEMS) ultrasonic transducer array composed of numerous micro-units. Its structure, from top to bottom, typically includes a matching layer for acoustic impedance matching, a piezoelectric sensor array capable of emitting and receiving ultrasonic waves, an integrated circuit layer responsible for signal control and processing, and a substrate providing support and connectivity. The piezoelectric sensor array emits ultrasonic pulses towards the finger. The ultrasonic waves penetrate the display module stack to reach the finger, generating reflected echoes with characteristic information due to the ridges and valleys of the fingerprint and differences in subcutaneous structure. After capturing these signals containing depth information, the piezoelectric sensor array performs preliminary processing by an internal chip, and then reconstructs a high-precision three-dimensional fingerprint image using algorithms.

[0041] The ultrasonic fingerprint sensor 102 not only acquires the surface texture of fingerprints but also gathers three-dimensional biometric information, including ridge depth and subcutaneous features. This enables high-precision recognition while providing inherent liveness detection capabilities. This characteristic also makes it highly adaptable to the environment, unaffected by minor water stains, oil, or everyday wear and tear on the finger surface, maintaining a stable and reliable recognition rate even with wet hands or a screen protector. Furthermore, the entire recognition process is fast and smooth, requiring no strong light stimulation, resulting in a quiet and seamless user experience. In terms of the overall display module design, its compact size and strong penetration capabilities enable more flexible full-screen layouts and a simpler integrated structure.

[0042] The cover plate 103 is attached to the display side of the display panel 101, forming the outermost protective interface of the display module. Specifically, the cover plate 103 is usually made of high-hardness, high-transmittance glass material, such as chemically strengthened glass or special microcrystalline glass, which provides reliable physical protection while ensuring clear display of content and natural and smooth touch operation.

[0043] Multiple grooves 1031 with specific geometric shapes are formed on the inner surface of the cover plate 103. The cross-section of the grooves 1031 gradually narrows along the direction away from the display panel 101, forming a tapered ultrasonic waveguide structure in space. The orthographic projection of the grooves 1031 on the reference plane corresponds to the orthographic projection of the ultrasonic fingerprint sensor 102 on the reference plane, so that the area where the multiple grooves 1031 are located exactly covers the effective working range of the ultrasonic fingerprint sensor 102.

[0044] From an acoustic perspective, multiple grooves 1031 with gradually decreasing cross-sectional areas can form a set of embedded acoustic concave lens systems. For example... Figure 3 As shown, when the ultrasonic waves emitted by the ultrasonic fingerprint sensor 102 pass through the cover plate 103 and are transmitted to the finger, the acoustic concave lens system formed by the groove 1031 can guide and converge the ultrasonic waves, causing the wavefront that might otherwise diffuse to concentrate towards the fingerprint contact area. Similarly, as Figure 4 As shown, the ultrasonic waves reflected from the fingerprint ridge will be refocused and guided to the receiving unit of the ultrasonic fingerprint sensor 102 when they pass through the acoustic concave lens system formed by the groove 1031 on their return journey.

[0045] In the display module provided in this embodiment, multiple grooves 1031 with gradually decreasing cross-sectional areas on the cover plate 103 collectively constitute an embedded acoustic concave lens system. This acoustic concave lens system can effectively guide and converge ultrasonic waves, significantly improving the overall efficiency of ultrasonic signals during transmission. Specifically, it can improve the utilization rate of transmitted signal energy and enhance the signal-to-noise ratio and clarity of the returned echo, enabling the ultrasonic fingerprint sensor 102 to collect richer and more accurate three-dimensional fingerprint features. Therefore, it can effectively suppress information loss caused by material interface reflection and signal scattering, thereby comprehensively improving the accuracy of ultrasonic fingerprint recognition and the reliability of system operation.

[0046] In some embodiments, such as Figure 2 As shown, the display module also includes a filling material layer 1032 filled in the groove 1031; the ultrasonic refractive index of the filling material layer 1032 is greater than the ultrasonic refractive index of the cover plate 103.

[0047] In the specific structure of this display module, the interior of the groove 1031 is filled with a filling material layer 1032, which is made of a specialized acoustic material. The ultrasonic refractive index of the filling material layer 1032 is greater than that of the cover plate 103 body material, allowing ultrasonic waves to undergo more expected refraction at the interface between the filling material layer 1032 and the cover plate 103 when passing through the groove 1031. By actively controlling the propagation path and wavefront shape of ultrasonic waves in different media, the transmission efficiency and focusing performance of the ultrasonic signal within the cover plate 103 are further optimized. This, combined with the geometric structure of the groove 1031, enhances the accuracy of ultrasonic fingerprint recognition and the reliability of the system.

[0048] In some embodiments, such as Figure 2 As shown, the display module also includes: an optical adhesive layer 104 located on the side of the cover plate 103 near the display panel 101; the difference between the ultrasonic refractive index of the filling material layer 1032 and the ultrasonic refractive index of the optical adhesive layer 104 is less than a threshold.

[0049] A polarizer 105 is typically provided between the display panel 101 and the cover plate 103. The main function of the polarizer 105 is to polarize the incident ambient light, converting it into polarized light in a specific direction. This effectively suppresses the reflection and scattering of light at the material interfaces inside the display panel (especially the anode surface of the light-emitting device), preventing stray light from escaping again and entering the human eye. This significantly improves the visibility, contrast, and display clarity of the display panel 101 in strong light environments, ensuring that users can still obtain a stable and comfortable viewing experience under various lighting conditions.

[0050] The polarizer 105 is typically bonded tightly to the cover plate 103 above it via an optical adhesive layer 104. This optical adhesive layer 104 not only has high light transmittance and excellent adhesive strength, but also effectively matches the refractive indices of different materials. This ensures structural stability while minimizing light reflection and scattering at the interface, thus ensuring the purity of the displayed image and the effective transmission of brightness.

[0051] The difference between the ultrasonic refractive index of the filling material layer 1032 and the ultrasonic refractive index of the optical adhesive layer 104 is controlled within a very small range, and can be considered to be similar or identical. This effectively suppresses unnecessary reflection and scattering of ultrasonic waves at the interface between the two, reducing signal attenuation and distortion. At the same time, this refractive index configuration is also coordinated with the material properties of the cover plate 103, further optimizing the propagation continuity of ultrasonic waves in the multilayer composite structure, thereby providing a more stable and efficient signal transmission path for ultrasonic fingerprint recognition.

[0052] Specifically, the filler layer 1032 can use liquid optical adhesive (LOCA / OCR) as its base material. Before curing, this material exhibits good flowability and filling properties, enabling it to fully wet and adhere to the complex microstructure surface of the groove 1031, forming a uniform and bubble-free filler layer 1032. After curing, the liquid optical adhesive not only possesses excellent optical transparency and physical stability, but its acoustic properties (especially the ultrasonic refractive index) can also be adjusted through formulation to achieve good matching with adjacent film layers, thereby synergistically optimizing the overall performance of display and fingerprint recognition at both optical and acoustic levels.

[0053] In some embodiments, such as Figure 2 As shown, the display module also includes a support layer 106 located between the display panel 101 and the ultrasonic fingerprint sensor 102; the support layer 106 has an opening; the opening exposes the ultrasonic fingerprint sensor 102.

[0054] The support layer 106 can be made of materials such as stainless steel, titanium alloy, carbon fiber, or graphene. While providing excellent mechanical support, it also achieves lightweight and high strength of the display module through its own structure or composite properties. In terms of acoustic design, since the support layer 106 is generally not suitable for direct transmission of ultrasonic waves, an opening is provided at the location of the corresponding ultrasonic fingerprint sensor 102. This allows the ultrasonic signal to penetrate the area with minimal loss, effectively ensuring the integrity of ultrasonic transmission and the response performance of the fingerprint recognition system.

[0055] Figure 5 This is a schematic diagram of another display module provided in an embodiment of the present disclosure. Figure 5 The display module shown is Figure 2 The difference in the display module shown is that, Figure 2 In the display module shown, the ultrasonic fingerprint sensor 102 is disposed on the side of the support layer 106 away from the display panel 101, and the ultrasonic fingerprint sensor 102 is exposed by providing an opening in the support layer 106. Figure 5 In the display module shown, the ultrasonic fingerprint sensor 102 is directly embedded inside the opening of the support layer 106. This integrated design brings the ultrasonic fingerprint sensor 102 closer to the surface of the cover plate 103, effectively shortening the physical path of the ultrasonic waves during propagation. This reduces the attenuation and distortion of the ultrasonic signal in the multi-layer medium, helping to improve the clarity and recognition accuracy of fingerprint imaging. Simultaneously, this embedded solution avoids the need for additional structural layers stacked above the ultrasonic fingerprint sensor 102, which helps to reduce the overall thickness of the display module, pushing display modules towards thinner and more compact designs, thereby effectively improving the user experience.

[0056] In some embodiments, such as Figure 2 As shown, the width a of the groove 1031 is 40 micrometers to 60 micrometers, the depth b is 60 micrometers to 90 micrometers, and the distance c between adjacent grooves 1031 is 10 micrometers to 30 micrometers.

[0057] The width a of the groove 1031 is designed to be between 40 micrometers and 60 micrometers (e.g., 50 micrometers) to match the typical width range of adult fingerprint ridges (approximately 30 to 70 micrometers), thereby better capturing the morphological features of the fingerprint.

[0058] The height b of the groove needs to satisfy the acoustic phase delay condition N×π / 2, that is, to form a half-wave resonance to enhance the signal. The calculation formula is: b=λ / (4×(1-V1 / V2). Where N is an integer, and to reduce the impact on the display effect, it is usually recommended to take N=1; λ is the ultrasonic wavelength, generally 200 micrometers to 300 micrometers (corresponding to a frequency of about 20MHz); V1 and V2 are the propagation speeds of ultrasonic waves in the cover plate 103 and the filling material layer 1032, respectively, with typical values ​​of about 5500m / s and 1000m / s, respectively. Substituting into the calculation, the depth b is about 60 micrometers to 90 micrometers, for example 80 micrometers.

[0059] Based on the consideration of machining tolerances, two requirements need to be met: one is to have a complete concave lens structure to avoid the inability to form a half-length wavelength difference, and the other is to make the concave lenses as dense as possible while taking into account the machining tolerances of the concave lenses to improve the resolution. Currently, the tolerance of laser etching is about 10 micrometers, and the distance between adjacent grooves 1031 is 10 micrometers to 30 micrometers, for example, 20 micrometers.

[0060] In some embodiments, the shape of the groove 1031 includes at least one of the following: hemispherical, semi-cylindrical, frustum, frustum-cylindrical, pyramidal, and prism.

[0061] The groove 1031 can be designed in different geometric shapes according to specific acoustic and structural requirements, including but not limited to one or more combinations of hemispherical, semi-cylindrical, frustum, frustum prism, pyramidal, or prism shapes. These grooves 1031 of different shapes have their own characteristics in terms of sound wave transmission, signal focusing, and matching degree with fingerprint ridge structure, providing a flexible and reliable physical carrier for optimizing ultrasonic wave propagation path and improving fingerprint imaging quality.

[0062] Secondly, this disclosure provides a display device, which includes a display module as provided in any of the above embodiments. The display device can be any product or component with display functionality, such as a smartphone, monitor, laptop computer, digital photo frame, or navigator. Its implementation principle is similar to that of the display module described above, and will not be repeated here.

[0063] Thirdly, embodiments of this disclosure provide a method for manufacturing a display module. Figure 6 This is a schematic flowchart of a method for manufacturing a display module according to an embodiment of the present disclosure, as shown below. Figure 6 As shown, the method for preparing the display module includes the following steps S601 to S603.

[0064] S601 assembles an ultrasonic fingerprint recognition sensor on the non-display side of the display panel.

[0065] In step S601 above, the ultrasonic fingerprint sensor 102 is precisely assembled onto the back of the display panel 101 (i.e., the non-display side). This step requires ensuring that the ultrasonic fingerprint sensor 102 is accurately positioned on the display panel 101 and corresponds in projection to the fingerprint recognition area of ​​the subsequently covered cover 103, so as to lay the foundation for the alignment of the subsequent acoustic structure.

[0066] S602 uses etching or micron-level imprinting processes to form multiple grooves on one side of the cover plate.

[0067] In step S602 above, a series of regularly arranged grooves 1031 are fabricated on the side of the cover plate 103 facing the display panel 101 using precision processing techniques such as photolithography etching or micron-level imprinting. The cross-section of these grooves 1031 on a reference plane parallel to the display panel 101 is designed to taper, meaning their cross-sectional area gradually decreases along the direction away from the panel. Simultaneously, the orthographic projection of the grooves 1031 onto the reference plane must at least partially overlap with the sensing area of ​​the assembled ultrasonic fingerprint sensor 102 to construct an effective acoustic wave guidance path.

[0068] S603, attach the cover plate to the display side of the display panel.

[0069] In step S603 above, the cover plate 103 with the pre-processed groove 1031 is precisely bonded to the display side surface of the display panel 101 using a high-transmittance adhesive material such as an optical adhesive layer 104. During the bonding process, the relative positional relationship between the groove 1031 and the ultrasonic fingerprint recognition sensor 102 below must be maintained to ensure that the ultrasonic signal can be efficiently converged and transmitted through the groove 1031, thereby ultimately achieving a high-precision and high-reliability under-display fingerprint recognition function.

[0070] It should be noted that the dimensions of layers and regions may be exaggerated in the accompanying drawings for clarity. Furthermore, it is understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element, or there may be intermediate layers. Additionally, it is understood that when an element or layer is referred to as being "below" another element or layer, it can be directly below the other element, or there may be more than one intermediate layer or element. Furthermore, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it can be the only layer between the two layers or two elements, or there may be more than one intermediate layer or element. Similar reference numerals throughout indicate similar elements.

[0071] In the several embodiments provided in this disclosure, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the positions of the components shown are only logical functional positions, and in actual implementation, they may be arranged in other positions.

Claims

1. A display module, characterized in that, The display module includes: a display panel, an ultrasonic fingerprint recognition sensor located on the non-display side of the display panel, and a cover plate located on the display side of the display panel; The cover plate has multiple grooves on the side near the display panel; the cross-sectional area of ​​the grooves parallel to the reference plane gradually decreases in the direction away from the display panel; The orthographic projection of the groove on the reference plane at least partially overlaps with the orthographic projection of the ultrasonic fingerprint sensor on the reference plane; the reference plane is a plane parallel to the display panel.

2. The display module according to claim 1, characterized in that, The display module further includes: a filler material layer filling the groove; The ultrasonic refractive index of the filling material layer is greater than that of the cover plate.

3. The display module according to claim 2, characterized in that, The display module further includes: an optical adhesive layer located on the side of the cover plate near the display panel; The difference between the ultrasonic refractive index of the filling material layer and the ultrasonic refractive index of the optical adhesive layer is less than a threshold value.

4. The display module according to claim 3, characterized in that, The material of the filling material layer includes: liquid optical adhesive.

5. The display module according to claim 3, characterized in that, The display module further includes a support layer located between the display panel and the ultrasonic fingerprint sensor; The support layer has an opening; the opening exposes the ultrasonic fingerprint sensor.

6. The display module according to claim 3, characterized in that, The display module further includes a support layer located on the side of the display panel opposite to the cover plate; The support layer has an opening; the ultrasonic fingerprint sensor is embedded in the opening.

7. The display module according to claim 1, characterized in that, The groove has a width of 40 to 60 micrometers, a depth of 60 to 90 micrometers, and a distance of 10 to 30 micrometers between adjacent grooves.

8. The display module according to claim 1, characterized in that, The shape of the groove includes at least one of the following: hemispherical, semi-cylindrical, frustum, frustum-cylindrical, pyramidal, and prism.

9. A display device, characterized in that, The display device includes the display module as described in any one of claims 1 to 8.

10. A method for manufacturing a display module, characterized in that, The preparation method includes: The ultrasonic fingerprint sensor is assembled on the non-display side of the display panel; Multiple grooves are formed on one side of the cover plate using etching or micron-level imprinting processes; The cover plate is attached to the display side of the display panel; the cross-sectional area of ​​the groove parallel to the reference plane gradually decreases in the direction away from the display panel; the orthographic projection of the groove on the reference plane at least partially overlaps with the orthographic projection of the ultrasonic fingerprint sensor on the reference plane; the reference plane is a plane parallel to the display panel.

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