Display module and display device

Abstract

A display module and a display device are provided. The display module has a display side and a backlight side disposed opposite to each other. The display module includes: a display panel; and a first back film layer located on the side of the display panel away from the display. The first back film layer includes: a first adhesive layer located on the side of the display panel away from the display; a first buffer layer located on the side of the first adhesive layer away from the display panel; a second adhesive layer located on the side of the first buffer layer away from the first adhesive layer; a second buffer layer located on the side of the second adhesive layer away from the first buffer layer; and a thermally conductive layer located on the side of the second buffer layer away from the second adhesive layer. Under the same compression ratio, the compressive rebound stress value of the first buffer layer is different from the compressive rebound stress value of the second buffer layer.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a display module and a display device. Background Art

[0002] With the advancement of display technology, display devices (such as mobile phones, laptops, or tablets) are increasingly used in people's lives. Display devices include display modules. As display devices become thinner and lighter, the thickness of display modules is also gradually decreasing. However, the thinning of display modules can easily lead to problems such as mold marks during the lamination process and reduced impact resistance.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] In one aspect, a display module is provided. The display module has a display side and a backlight side disposed opposite to each other, wherein the display module comprises: a display panel; and a first back film layer located on the side of the display panel away from the display side.

[0005] Wherein, the first back film layer comprises:

[0006] a first adhesive layer located on a side of the display panel away from the display;

[0007] a first buffer layer located on a side of the first adhesive layer away from the display panel;

[0008] a second bonding layer located on a side of the first buffer layer away from the first bonding layer;

[0009] a second buffer layer located on a side of the second adhesive layer away from the first buffer layer; and

[0010] a heat conducting layer located on a side of the second buffer layer away from the second bonding layer,

[0011] Wherein, under the same compression ratio, the compressive rebound stress value of the first buffer layer is different from the compressive rebound stress value of the second buffer layer.

[0012] According to some exemplary embodiments, at the same compression ratio, a compressive rebound stress value of the first buffer layer is smaller than a compressive rebound stress value of the second buffer layer.

[0013] According to some exemplary embodiments, at the same compression ratio, the compressive rebound stress value of the first buffer layer is greater than the compressive rebound stress value of the second buffer layer.

[0014] According to some exemplary embodiments, in a direction from the display side to the backlight side, a thickness of the first buffer layer is substantially equal to a thickness of the second buffer layer.

[0015] According to some exemplary embodiments, in a direction from the display side to the backlight side, a ratio of a thickness of the first buffer layer to a thickness of the first adhesive layer is in a range of 2-3; and / or,

[0016] In a direction from the display side to the backlight side, a ratio of a thickness of the second buffer layer to a thickness of the second adhesive layer is in a range of 2-3.

[0017] According to some exemplary embodiments, in a direction from the display side to the backlight side, a thickness of the first buffer layer is greater than a thickness of the heat conducting layer.

[0018] According to some exemplary embodiments, a plurality of openings are provided on at least one of the first buffer layer and the second buffer layer.

[0019] According to some exemplary embodiments, the material of the first bonding layer includes textured glue; and / or,

[0020] The material of the first buffer layer includes ultra-clean foam; and / or,

[0021] The material of the second adhesive layer includes textured glue; and / or,

[0022] The material of the second buffer layer includes ultra-clean foam; and / or,

[0023] The material of the heat conducting layer includes aluminum.

[0024] According to some exemplary embodiments, the display module further includes: a second back film layer located between the display panel and the first back film layer; and

[0025] The driving circuit layer is located on a side of the first back film layer away from the display panel.

[0026] In another aspect, a display device is provided, wherein the display device includes the display module as described in any one of the above items. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0028] Figure 1 is a structural diagram of a display device according to an embodiment of the present disclosure;

[0029] Figure 2 It is along Figure 1A schematic cross-sectional view taken along line AA';

[0030] Figure 3 It is a structural schematic diagram of the first back film layer according to the related art;

[0031] Figure 4 is a schematic structural diagram of a first back film layer according to some embodiments of the present disclosure;

[0032] Figure 5 is a schematic diagram of the first buffer layer or the second buffer layer when it is compressed and deformed;

[0033] Figure 6 is a simulation comparison diagram of the maximum principal strain generated by the display panels of display modules with three different structures during a ball drop test according to an embodiment of the present disclosure;

[0034] Figure 7 is a schematic structural diagram of a display module according to the related art; and

[0035] Figure 8 4 is a schematic structural diagram of a display module according to an embodiment of the present disclosure.

[0036] It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present invention, the sizes of layers, structures or regions may be enlarged or reduced, that is, these drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0038] It should be noted that in the drawings, the sizes and relative sizes of elements may be exaggerated for clarity and / or descriptive purposes. Thus, the sizes and relative sizes of the individual elements are not necessarily limited to those shown in the drawings. In the specification and drawings, the same or similar reference numerals indicate the same or similar parts.

[0039] Unless otherwise defined, technical or scientific terms used in this disclosure should have the ordinary meanings understood by those of ordinary skill in the art. The terms "first," "second," and similar terms used in this disclosure do not denote any order, quantity, or importance, but are simply used to distinguish different components. The terms "include," "comprising," and similar words mean that the element or object preceding the word encompasses the elements or objects listed after the word, and their equivalents, without excluding other elements or objects.

[0040] Unless otherwise specified, directional terms such as "upper," "lower," "left," "right," "inner," and "outer" are used herein to indicate positions or relationships based on the figures shown. These terms are intended solely to facilitate the description of the present disclosure and are not intended to indicate or imply that the devices, components, or parts referred to must have, be constructed, or operate in a specific orientation. It should be understood that when the absolute positions of the objects being described change, the relative positions they represent may also change accordingly. Therefore, these directional terms should not be construed as limiting the present disclosure.

[0041] As used herein, the terms "substantially," "about," "approximately," and other similar terms are used as terms of approximation rather than as terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art. To account for factors such as process fluctuations, measurement problems, and errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system), "about" or "approximately," as used herein, are inclusive of the stated value and mean within an acceptable range of deviation for that particular value as determined by one of ordinary skill in the art. For example, "approximately" can mean within one or more standard deviations, or within ±10% or ±5% of the stated value.

[0042] In this document, the directional expressions "first direction," "second direction," and "third direction" are used to describe different directions of a display module, such as the horizontal and vertical directions of the display module. It should be understood that such expressions are merely exemplary descriptions and are not intended to limit the present disclosure.

[0043] In this document, unless otherwise specified, the expression "electrically connected" may mean that two components or elements are directly electrically connected, for example, component or element A is in direct contact with component or element B, and electrical signals can be transmitted between the two components; it may also mean that two components or elements are electrically connected through a conductive medium such as a conductive wire, for example, component or element A is electrically connected to component or element B through a conductive wire to transmit electrical signals between the two components or elements; it may also mean that two components or elements are electrically connected through at least one electronic component, for example, component or element A is electrically connected to component or element B through at least one thin-film transistor to transmit electrical signals between the two components or elements.

[0044] In order to facilitate understanding by relevant personnel, some technical terms of the present disclosure are briefly explained.

[0045] Compression force deformation (CFD): This refers to the force generated by the rearrangement of molecules within an object during deformation. This force is called compression rebound stress. It imparts a degree of elasticity to an object, allowing it to return to its original shape when the force is removed. Higher compression rebound stress indicates a greater rebound stress after compression.

[0046] Point impact and surface impact: During the preparation, testing or use of the display module, the impact on the display module can be divided into point impact and surface impact according to the different collision methods. The main difference between point impact and surface impact is the size of the force-bearing area. In case of point impact, the force-bearing area is smaller and the stress is more concentrated; in case of surface impact, the force-bearing area is larger and the stress is more dispersed. For example, in the process of module preparation, when binding the PCB board on the back, a certain pressure needs to be applied with a jig for attachment. The force-bearing area of ​​the display module is larger, and the stamping process will cause surface impact on the display module. For another example, when the display module is subjected to a drop ball test, the force-bearing area of ​​the display module is smaller, and the drop ball test causes a point impact on the display module.

[0047] With the development of display technology, display terminal manufacturers are pursuing the concept of extremely thin and light products and need to reduce the weight of their products. In recent years, foldable display modules have gradually been promoted in the fields of foldable mobile phones, rollable tablets, and foldable tablets. Currently, the most common method used for foldable display modules is to reduce the thickness of the cover glass (CG), which has the most obvious effect. The thinnest CG on the market is about 0.4mm thick. CGs less than 0.4mm cannot meet the requirements of both strength and performance.

[0048] To further reduce the weight of the display module, relevant technicians chose to thin the rear support of the screen. Currently, the mainstream large-size screen rear support structure typically uses stainless steel, a relatively hard material, as the backplane, combined with a single layer of cushioning foam for support, while also meeting the specifications for falling balls and addressing the film printing problem caused by the lamination process. However, stainless steel is heavy and cannot meet the demand for thin and light products.

[0049] An embodiment of the present disclosure provides a display module. Specifically, the display module has a display side and a backlight side that are arranged in opposite directions. The display module includes: a display panel; and a first back film layer located on the display panel's side away from the display. The first back film layer includes: a first adhesive layer located on the display panel's side away from the display; a first buffer layer located on the first adhesive layer's side away from the display panel; a second adhesive layer located on the first buffer layer's side away from the first adhesive layer; a second buffer layer located on the second adhesive layer's side away from the first buffer layer; and a heat conductive layer located on the second buffer layer's side away from the second adhesive layer. Under the same compression ratio, the compression rebound stress value of the first buffer layer is different from the compression rebound stress value of the second buffer layer.

[0050] Through such a design, a double-layer buffer layer structure can be utilized to improve the impact resistance of the display module, while reducing the weight of the display module, which is conducive to achieving a lighter and thinner display module.

[0051] Figure 1 is a structural diagram of a display device according to an embodiment of the present disclosure, Figure 2 It is along Figure 1 Schematic cross-sectional view taken along line AA'.

[0052] For example, in the embodiments of the present disclosure, in combination with reference to Figure 1 and Figure 2 A display device 1000 is provided. Display device 1000 includes a display module 100 having a display side M1 and a backlight side M2 ​​disposed opposite to each other. Display module 100 includes a display panel 10 for displaying images. Display side M1 of display module 100 is the side of display panel 10 viewed by a user; that is, the display side of the display module and the display side of the display panel are the same side.

[0053] The display side of the display panel 10 includes a display area AA and a peripheral area NA. The display area AA is the area of ​​the display panel 10 for displaying images, and the peripheral area NA is the area of ​​the display side of the display panel 10 excluding the display area AA.

[0054] The display area AA can have various shapes. For example, the display area AA can be provided in various shapes such as a polygon (e.g., a rectangle) with a closed shape including straight edges, a circle, an ellipse, etc. with curved edges, and a semicircle, a semi-ellipse, etc. with straight edges and curved edges. In an embodiment of the present disclosure, the display area AA is provided as an area with a rounded rectangular shape including straight edges. It should be understood that this is only an exemplary embodiment of the present disclosure and not a limitation of the present disclosure. The peripheral area NA can be provided on at least one side of the display area AA. In an embodiment of the present disclosure, the peripheral area NA can surround the periphery of the display area AA.

[0055] Depending on the display principle, the display panel 10 can be any one of an organic light emitting diode (OLED) display panel, a quantum dot light emitting diode (QLED) display panel, a micro light emitting diode (Mini LED or Micro LED) display panel and a liquid crystal display (LCD) panel.

[0056] Depending on whether the display panel 10 is bendable, the display panel 10 may be a rigid display panel or a flexible display panel.

[0057] For example, referring to Figure 2 The display panel 10 is a flexible display panel and includes a display portion 11, a bent portion 12, and a binding portion 13, which are connected in sequence. The bent portion 12 is bent so that the binding portion 13 is located on the back side of the display panel 10. The back side of the display panel 10 is the side opposite to the display side of the display panel 10. In other words, the back side of the display panel faces the backlight side M2. In an orthographic projection onto the XY plane, the display area AA is located within the display portion 11.

[0058] For example, the display module 100 may further include a connection layer 30 and a cover plate 40. The display panel 10, the connection layer 30 and the cover plate 40 are sequentially arranged along the third direction Z. The third direction Z may be parallel to the direction from the backlight side M2 ​​to the display side M1.

[0059] Exemplarily, the cover plate 40 is disposed on the display side of the display panel 10 to protect the display panel 10. The cover plate 40 covers the display panel 10, that is, the cover plate 40 may cover the display area AA and the peripheral area NA of the display side of the display panel 10.

[0060] For example, see Figure 2 The boundary of the cover plate 40 is further away from the display portion 11 than the boundary of the bent portion 12 that is farthest from the display portion 11. The cover plate 40 extends in the XY plane, such that the upper and lower surfaces of the cover plate 40 are parallel to the XY plane. The cover plate 40 can be made of a transparent material such as acrylic or glass, which is not limited in the present embodiment.

[0061] The connection layer 30 is disposed between the display panel 10 and the cover plate 40 and is used to connect the display panel 10 and the cover plate 40. The material of the connection layer 30 can include at least one of optically clear adhesive (OCA), liquid optically clear adhesive (LOCA), or UV-curable adhesive, but is not limited thereto. Other adhesive materials capable of achieving a connection can also be used. For example, the connection layer 30 is an optically clear hot-melt adhesive film (TOCA).

[0062] Exemplarily, the display module 100 may further include a polarizer (POL) 20. The polarizer 20 is disposed between the connecting layer 30 and the display panel 10 and has polarization properties. The polarizer 20 is configured to convert unpolarized light emitted by the display panel 10 and passing through the polarizer 20 into polarized light, thereby improving the uniformity of the light emitted from the display panel 10, thereby reducing rainbow patterns appearing in the image displayed by the display panel 10, and improving the display effect of the display module 100. The polarizer 20 may be a transmissive polarizer, a reflective polarizer, a semi-transmissive reflective polarizer, a compensating polarizer, or other types of polarizers, and the embodiments of the present disclosure are not limited thereto.

[0063] For example, the display module 100 may further include a first backing film layer 60. The first backing film layer 60 is located on a side of the display panel 10 away from the display side M1. The first backing film layer 60 can buffer stress acting on the display panel 10 and dissipate heat generated by the display panel 10 during operation, thereby providing a certain degree of protection for the display panel 10.

[0064] Exemplarily, the first back film layer 60 is disposed between the display portion 11 and the binding portion 13 .

[0065] Exemplarily, the display module may further include a drive circuit layer 200 located on a side of the first backing film layer 60 away from the display panel 10. For example, the drive circuit layer 200 may include a rigid printed circuit board 201 (Printed Circuit Board, PCB), a flexible printed circuit board 202 (Flexible Printed Circuitboard, FPC), or a rigid-flex board. The drive circuit layer 200 is configured to transmit electrical signals to the display panel 10. The drive circuit layer 200 may also include a driver chip 203 (Integrated Circuit, IC) for providing control signals to the display panel 10.

[0066] At least a portion of the drive circuit layer 200 (e.g., a PCB) needs to be fixedly soldered to the backlight side of the display module using a stamping process to achieve electrical connection between some components or structures in the drive circuit layer 200 and the display panel 10. During the stamping process, a jig is required to apply a certain amount of pressure to the display module. If the impact resistance of the first back film layer is insufficient, film marks can easily form on the display module, affecting the display effect.

[0067] Figure 3 It is a structural schematic diagram of the first back film layer according to the related art.

[0068] In the related art, the first back film layer 60 generally adopts a stacked structure including a stainless steel layer + a single buffer layer. Figure 3 The first back film layer 60 includes a first adhesive layer 61, a buffer layer 62, a second adhesive layer 63 and a heat conducting layer 64 arranged in sequence along the Z1 direction. The Z1 direction is the direction from the display side M1 to the backlight side M2.

[0069] Exemplarily, the material of the heat-conducting layer 64 includes stainless steel. Stainless steel has a high hardness and can provide good support and impact resistance. Stainless steel can also dissipate heat.

[0070] For example, the buffer layer 62 may include an ultra-clean foam material, which may play a buffering role, further reduce the stress on the display panel when it is impacted, and protect the display panel.

[0071] For example, the materials of the first adhesive layer 61 and the second adhesive layer 62 may include grid glue. The first adhesive layer 61 and the second adhesive layer 62 have bonding and air venting functions, which can improve the flatness of the bonding and avoid wrinkles that affect the display effect.

[0072] In order to ensure the protective effect of the first back film layer, each film layer in the first back film layer is required to have a certain thickness.

[0073] For example, in the Z1 direction, the thickness h1 of the first adhesive layer 61 is approximately 0.03 mm, the thickness h2 of the buffer layer 62 is approximately 0.15 mm, the thickness h3 of the second adhesive layer 63 is approximately 0.03 mm, and the thickness of the thermal conductive layer 64 is approximately 0.08 mm. The total thickness h0 of the first backing film layer 60 in the Z1 direction is approximately 0.29 mm.

[0074] Since the density of stainless steel is relatively high, for example, the density of stainless steel is about 7.8g / mm 3 , resulting in a heavy weight of the first back film layer 60, which is not conducive to making the display module thinner and lighter.

[0075] To further reduce the weight of the display module, the disclosed embodiments employ a laminated structure comprising an aluminum layer and a double-layer buffer layer to provide cushioning protection and heat dissipation. The double-layer buffer layer can have different compression rebound stress values, effectively cushioning both point and surface impacts, compensating for the limited impact resistance caused by aluminum's low hardness.

[0076] Figure 4 Schematic diagram of the structure of the first back film layer according to some embodiments of the present disclosure.

[0077] For example, in the embodiments of the present disclosure, in combination with reference to Figure 2 and Figure 4 The display module may include a first back film layer 60 located on the display panel 10 away from the display side M1.

[0078] The first back film layer 60 may include: a first adhesive layer 601 located on the side of the display panel 10 away from the display side MM1; a first buffer layer 602 located on the side of the first adhesive layer 601 away from the display panel 10; a second adhesive layer 603 located on the side of the first buffer layer 602 away from the first adhesive layer 601; a second buffer layer 604 located on the side of the second adhesive layer 603 away from the first buffer layer 602; and a thermal conductive layer 605 located on the side of the second buffer layer 604 away from the second adhesive layer 603.

[0079] Exemplarily, the material of the first bonding layer 601 includes textured glue; and / or, the material of the first buffer layer 602 includes ultra-clean foam; and / or, the material of the second bonding layer 603 includes textured glue; and / or, the material of the second buffer layer 604 includes ultra-clean foam; and / or, the material of the thermal conductive layer 605 includes aluminum.

[0080] The first adhesive layer 601 and the second adhesive layer 603 have adhesive and venting functions, which can improve the flatness of the bonding and avoid wrinkles that affect the display effect.

[0081] By using aluminum as the heat conducting plate and support plate, it can play a good role in heat conduction and support. Since the density of aluminum is about 2.7g / mm 3 , the density of stainless steel is about 7.8g / mm 3 Using aluminum instead of stainless steel for the heat sink and support plate significantly reduces the weight of the first backing film layer 60 under the same dimensions. For example, using aluminum as the heat conduction layer can reduce the weight of the heat conduction layer by approximately 65% ​​compared to using stainless steel as the heat conduction layer under the same dimensions, thus facilitating a thinner and lighter display module.

[0082] Although aluminum has a lower density than stainless steel, it also has disadvantages. For example, aluminum's hardness is inferior to stainless steel, and its impact resistance is not as good as stainless steel's. Table 1 shows the hardness values ​​of various material types (e.g., P1-P7), each of which includes three Vickers hardness measurements. As shown in Table 1, the average Vickers hardness of the latest super-hard aluminum material, P1, is approximately 84, which is approximately 35 points lower than the Vickers hardness of P6, a rolled copper material commonly used in mobile phone displays, and approximately 201 points lower than the Vickers hardness of P7, a stainless steel material.

[0083] Table 1 Hardness values ​​of different types of materials

[0084]

[0085] Using aluminum instead of stainless steel in the first back film layer can easily lead to a decrease in the impact resistance of the first back film layer. In the embodiment of the present disclosure, a double-layer buffer layer (e.g., a first buffer layer 602 and a second buffer layer 604) is designed between the thermal conductive layer 605 and the display panel 10. The double-layer buffer layer has different compression rebound stress values, which can improve the problem of insufficient impact resistance caused by using aluminum as the thermal conductive layer. While achieving a lightweight display module, it ensures that the first back film layer has good impact resistance, support, and heat dissipation functions, can meet customers' drop ball test requirements and avoid mold printing problems caused by binding circuit boards.

[0086] For example, at the same compression ratio, the compressive rebound stress value of the first buffer layer 602 is different from the compressive rebound stress value of the second buffer layer 604 .

[0087] Figure 5 It is a schematic diagram of the first buffer layer or the second buffer layer when it is compressed and deformed.

[0088] For example, when the first buffer layer 602 and / or the second buffer layer 604 is impacted by the external force F0, they are compressed to a certain degree. For example, the compressed thickness h200 of the first buffer layer 602 and / or the second buffer layer 604 is 25% or 50% of the initial thickness h100. Herein, the ratio of the compressed thickness h200 to the initial thickness h100 is referred to as the compression ratio.

[0089] Exemplarily, the first buffer layer 602 has a first compressive rebound stress value CFD1 , and the second buffer layer 604 has a second compressive rebound stress value CFD2 .

[0090] Under the same compression ratio, for example, a compression ratio within the range of 20%-30%, a first compressive rebound stress value CFD1 of the first buffer layer 602 is different from a second compressive rebound stress value CFD2 of the second buffer layer 604 .

[0091] Table 2 shows the comparison of the point impact resistance and surface impact resistance of the first backing film layers of different structures and types.

[0092] Table 2 Comparison of point impact and surface impact resistance of different materials

[0093]

[0094] It should be noted that the “split type” in Table 2 refers to Figure 4 The first back film layer structure shown includes a double-layer buffer layer, and "integrated" refers to Figure 3 The structure of the first back film layer shown includes a single buffer layer; "A1 / A2 / A3" refers to the material models of different types of buffer layers, such as the models of different types of ultra-clean foam materials, for example, A1 can be "ISR-ACF-WPC" model foam, A2 can be "ISR-ACF-JPC" model foam, and A3 can be "ISR-ACF-JPC-B" model foam; "semi-closed cell" means that part of the buffer layer includes a certain number of open cells or through holes, and "closed cell" means that the buffer layer does not contain open cells or through holes; "L1 / L2 / L3 / L4" refers to the performance level of different first back film layers in resisting surface impact in the embossing process, wherein the larger the number after L, the stronger the surface impact resistance and the smaller the probability of mold imprinting; "K1 / K2 / K3" refers to the impact absorption rate of different first back film layers in resisting point impact in the drop ball test, wherein the larger the number after K, the stronger the point impact resistance and the smaller the probability of damage to the display module in the drop ball test.

[0095] For example, the drop ball test can use an 8.34g ball to freely fall from a height of 15cm to impact the display module. The point impact absorption rate represented by K3 can be approximately 47.4%, the point impact absorption rate represented by K2 can be approximately 38.2%, and the point impact absorption rate represented by K1 can be approximately 24.2%.

[0096] By comparing the test results of various different first back film layers in Table 2, it can be seen that: the lower the CFD value of the buffer layer, the better the effect of resisting surface impact. For example, for the display module, when the large-area pressure applied on the backlight side in the imprinting process is transmitted to the display panel through the first back film layer, the buffer layer with a low CFD value (for example, the CFD value is in the range of 0.01-0.3MPa at a compression ratio of 25%) can block and absorb most of the force, so that the force transmitted to the display panel is basically 0, avoiding the generation of mold imprints and affecting the display effect; the higher the CFD value of the buffer layer, the better the effect of resisting point impact. For example, in the drop ball test, the buffer layer with a high CFD value (for example, the CFD value is in the range of 0.3-0.7MPa at a compression ratio of 25%) can absorb most of the point impact force, so that the force transmitted to the display panel is basically 0, avoiding damage to the display panel by the drop ball impact.

[0097] In order to take into account both point impact resistance and surface impact resistance, in the embodiment of the present disclosure, a first back film layer stacking structure including a double-layer buffer layer structure + an aluminum heat conductive layer is adopted. Under the same compression ratio, the CFD value of the double-layer buffer layer is different. Figure 4 , the CFD values ​​of the first buffer layer 602 and the second buffer layer 604 are different.

[0098] By designing two cushioning materials with different CFD values ​​within the stacked structure of the first backing film layer, the stress generated by different types of impact (such as point impact or surface impact) can be absorbed, thereby improving the first backing film's impact resistance, meeting customer drop ball testing requirements, and avoiding mold printing issues during the embossing process. The dual-layer cushioning layer compensates for the lack of aluminum hardness, ensuring that the first backing film layer meets the required impact resistance while reducing its weight, contributing to the thinness and lightness of the display module.

[0099] For example, referring to Figure 4 The first back film layer 60 may include a double buffer layer, for example, a first buffer layer 602 and a second buffer layer 604 , and the materials of the first buffer layer 602 and the second buffer layer 604 may include ultra-clean foam.

[0100] For example, at the same compression ratio, the compressive rebound stress (CFD) value of the first buffer layer 602 is smaller than the compressive rebound stress (CFD) value of the second buffer layer 604 .

[0101] For example, when the compression ratio is approximately 25%, the first compressive rebound stress value CFD1 of the first buffer layer 602 is in the range of 0.01-0.1 MPa, for example, the first compressive rebound stress value CFD1 of the first buffer layer 602 is approximately 0.01 MPa, 0.05 MPa, or 0.1 MPa. When the compression ratio is approximately 25%, the second compressive rebound stress value CFD2 of the second buffer layer 604 is in the range of 0.1-0.7 MPa, for example, the second compressive rebound stress value CFD2 of the second buffer layer 604 is approximately 0.1 MPa, 0.4 MPa, or 0.7 MPa.

[0102] For example, when the compression ratio is approximately 30%, the first compressive rebound stress value CFD1 of the first buffer layer 602 is in the range of 0.01-0.3 MPa, for example, the first compressive rebound stress value CFD1 of the first buffer layer 602 is approximately 0.01 MPa, 0.15 MPa, or 0.3 MPa. The second compressive rebound stress value CFD2 of the second buffer layer 604 is in the range of 0.3-0.7 MPa, for example, the second compressive rebound stress value CFD2 of the second buffer layer 604 is approximately 0.3 MPa, 0.5 MPa, or 0.7 MPa.

[0103] The first buffer layer 602 has a lower CFD value, which effectively buffers and absorbs surface impact pressure, thereby reducing the probability of stenciling during the imprinting process. The second buffer layer 604 has a higher CFD value, which effectively buffers and absorbs point impact pressure, thereby meeting the requirements of the drop ball test.

[0104] Through such a design, the impact resistance of the first back film layer can be improved, which is beneficial to improving the defect of insufficient impact resistance caused by insufficient hardness of the aluminum thermal conductive layer and is beneficial to achieving a lighter and thinner display module.

[0105] Illustratively, at the same compression ratio, the compressive rebound stress value of the first buffer layer 602 is greater than the compressive rebound stress value of the second buffer layer 604 .

[0106] For example, when the compression ratio is approximately 25%, the first compressive rebound stress value CFD1 of the first buffer layer 602 is in the range of 0.1-0.7 MPa, for example, the first compressive rebound stress value CFD1 of the first buffer layer 602 is approximately 0.1 MPa, 0.4 MPa, or 0.7 MPa. The second compressive rebound stress value CFD2 of the second buffer layer 604 is in the range of 0.01-0.1 MPa, for example, the second compressive rebound stress value CFD2 of the second buffer layer 604 is approximately 0.01 MPa, 0.05 MPa, or 0.1 MPa.

[0107] For example, when the compression ratio is approximately 30%, the first compressive rebound stress value CFD1 of the first buffer layer 602 is in the range of 0.3-0.7 MPa, for example, the first compressive rebound stress value CFD1 of the first buffer layer 602 is approximately 0.3 MPa, 0.5 MPa, or 0.7 MPa. The second compressive rebound stress value CFD2 of the second buffer layer 604 is in the range of 0.01-0.3 MPa, for example, the second compressive rebound stress value CFD2 of the second buffer layer 604 is approximately 0.01 MPa, 0.15 MPa, or 0.3 MPa.

[0108] The first buffer layer 602 has a high CFD value, which provides better cushioning and absorption of point impact pressure, meeting the requirements of the drop ball test. The second buffer layer 604 has a low CFD value, which provides better cushioning and absorption of surface impact pressure, reducing the probability of mold marks during the imprinting process.

[0109] Through such a design, the impact resistance of the first back film layer can be improved, which is beneficial to improving the defect of insufficient impact resistance caused by insufficient hardness of the aluminum thermal conductive layer and is beneficial to achieving a lighter and thinner display module.

[0110] In the disclosed embodiments, the double-layer buffer layer provides excellent buffering and absorption capabilities for both point impact and surface impact pressure, ensuring that the first backing film layer has excellent impact resistance against both point and surface impacts. Compared to a first backing film layer comprising a single-layer buffer layer and a stainless steel thermal conductive layer, the first backing film layer comprising a double-layer buffer layer and an aluminum thermal conductive layer in the disclosed embodiments is lighter and offers improved impact resistance, meeting customer drop ball test requirements while avoiding mold imprints and facilitating a thinner and lighter display module.

[0111] For example, in the direction Z1 from the display side to the backlight side, the thickness h12 of the first buffer layer 602 is substantially equal to the thickness h14 of the second buffer layer 604 .

[0112] It should be noted that “substantially equal” here means that the thickness ratio h12 / h14 of the two is in the range of 0.8-1.2.

[0113] For example, the thickness h12 of the first buffer layer 602 is approximately 0.08 mm, and the thickness h14 of the second buffer layer 604 is approximately 0.08 mm.

[0114] For example, in the direction Z1 from the display side to the backlight side, the ratio of the thickness h12 of the first buffer layer 602 to the thickness h11 of the first adhesive layer 601 is in the range of 2-3. For example, the thickness h12 of the first buffer layer 602 is approximately 0.08 mm, and the thickness h11 of the first adhesive layer 601 is approximately 0.03 mm.

[0115] For example, in the direction Z1 from the display side to the backlight side, the ratio of the thickness h14 of the second buffer layer 604 to the thickness h13 of the second adhesive layer 603 is in the range of 2 to 3. For example, the thickness h14 of the second buffer layer 604 is approximately 0.08 mm, and the thickness h13 of the second adhesive layer 603 is approximately 0.03 mm.

[0116] For example, in the direction Z1 from the display side to the backlight side, the thickness h12 of the first buffer layer 602 is greater than the thickness h15 of the heat conducting layer 605. For example, the thickness h12 of the first buffer layer 602 is about 0.08 mm, and the thickness h15 of the heat conducting layer 605 is about 0.05 mm.

[0117] Continue to refer to Figure 4 In the direction Z1 from the display side to the backlight side, the total thickness h10 of the first back film layer 60 is h11+h12+h13+h14+h15. For example, the total thickness h10 of the first back film layer 60 is about 0.27 mm.

[0118] and Figure 3Compared with the total thickness h0 (approximately 0.29 mm) of the first back film layer 60 shown as comprising a single-layer buffer layer + a stainless steel thermal conductive layer, the total thickness h10 of the first back film layer 60 comprising a double-layer buffer layer + an aluminum thermal conductive layer according to the embodiment of the present disclosure is approximately 0.27 mm. The thickness of the first back film layer is reduced by approximately 6.8%, which is conducive to further realizing the lightweight and thinness of the display module.

[0119] Figure 6 This is a simulation comparison diagram of the maximum principal strain generated by the display panels of display modules with three different structures during a ball drop test according to an embodiment of the present disclosure.

[0120] For example, Table 3 shows the structures of display modules in three different schemes, all of which include a cover plate 40, a connecting layer 30, a polarizing layer 20, a display panel 10, a second backing film layer 50, and a first backing film layer 60 stacked in sequence. The cover plate 40, connecting layer 30, polarizing layer 20, display panel 10, and second backing film layer 50 in the three schemes are made of essentially the same materials and have essentially the same properties, as well as essentially the same thickness. For example, the cover plate 40 is approximately 0.4 mm thick, the connecting layer 30 is approximately 0.15 mm thick, the polarizer 20 is approximately 0.105 mm thick, the display panel 10 is approximately 0.049 mm thick, and the second backing film layer 50 is approximately 0.088 mm thick. In the embodiments of the present disclosure, three different structures of the first backing film layer 60 are designed. The first backing film layer 60 of Option 1 includes: a 0.03 mm first adhesive layer (e.g., EMBO) + a 0.08 mm first buffer layer (e.g., WPC Foam) + a 0.03 mm second adhesive layer (e.g., EMBO) + a 0.08 mm second buffer layer (e.g., JPC-B Foam) + a 0.05 mm thermal conductive layer (e.g., aluminum foil). The first backing film layer 60 of Option 2 includes: a 0.03 mm first adhesive layer (e.g., EMBO) + a 0.08 mm first buffer layer (e.g., JPC-B Foam) + a 0.03 mm second adhesive layer (e.g., EMBO) + a 0.08 mm second buffer layer (e.g., WPC Foam) + a 0.05 mm thermal conductive layer (e.g., aluminum foil). The first backing film layer 60 of Option 3 includes: a 0.03 mm adhesive layer (e.g., EMBO) + a 0.16 mm buffer layer (e.g., JPC Foam) + a 0.05 mm thermal conductive layer (e.g., aluminum foil).

[0121] Table 3 Structures of display modules of three different schemes

[0122]

[0123] For example, the CFD value of WPC Foam is relatively high. For example, at a compression ratio of approximately 25%, the CFD value of WPC Foam is approximately 0.57. The CFD value of JPC-B Foam is relatively low. For example, at a compression ratio of approximately 25%, the CFD value of JPC-B Foam is approximately 0.019. The CFD value of JPC Foam is lower than that of WPC Foam. For example, at a compression ratio of approximately 25%, the CFD value of JPC Foam is approximately 0.16.

[0124] like Figure 6 As shown, the maximum principal strain of the display panel in Scheme 1 is approximately 0.0173‰, the maximum principal strain of the display panel in Scheme 2 is approximately 0.0181‰, and the maximum principal strain of the display panel in Scheme 3 is approximately 0.0453‰. The "maximum principal strain" refers to the degree of deformation of a certain area on the display panel. The larger the value of the "maximum principal strain", the more severe the deformation of the display panel and the worse the impact resistance of the first back film layer.

[0125] Combined with reference Figure 6 As shown in Table 3, the display module using a first backing film layer with a double-layer foam structure experienced significantly lower strain on the display panel during the drop ball test than the display module using a first backing film layer with a single-layer foam structure. This demonstrates that using a double-layer buffer layer with different CFD values ​​within the first backing film layer can better absorb the impact during the drop ball test, reducing the force on the display panel and, consequently, the strain on the display panel, thereby providing better protection for the display panel.

[0126] For example, in some embodiments of the present disclosure, reference is made to Figure 4 At least one of the first buffer layer 602 and the second buffer layer 604 is provided with a plurality of openings. The openings can release stress.

[0127] Through such a design, the stress accumulated in the first back film layer during the attachment process can be better released, thereby improving the attachment effect between the first back film layer and the display panel, which is beneficial to improving the protection effect of the first back film layer on the display panel.

[0128] For example, return reference Figure 2 The display module may further include a second backing film layer 50 located between the display panel 10 and the first backing film layer 60. The second backing film layer 50 is disposed on the non-display side (i.e., the backlight side) of the display panel 10. For example, the second backing film layer 50 is disposed on the side of the display portion 11 near the binding portion 13.

[0129] For example, the display module 100 may further include a third backing film layer 90. The third backing film layer 90 is disposed on the side of the binding portion 13 that is closer to the display portion 11. When the display panel 10 is bent via the bending portion 12 so that the binding portion 13 is disposed on the non-display side of the display portion 11, the second backing film layer 50 and the third backing film layer 90 can provide support to the display portion 11 and the binding portion 13 of the display panel 10, thereby achieving a better bending effect.

[0130] Exemplarily, the materials of the second backing film layer 50 and the third backing film layer 90 can be the same or different. For example, the materials of the second backing film layer 50 and the third backing film layer 90 can be one of polyethylene terephthalate (PET), polyimide (PI), or cycloolefin polymer (COP).

[0131] In some embodiments, see Figure 2 The display module 100 may further include a bending spacer 80. The bending spacer 80 is disposed between the display portion 11 and the binding portion 13 to prevent the bent display panel 10 from rebounding.

[0132] Exemplarily, one side of the bent gasket 80 is connected to the first back film layer 60 , and the other side is connected to the third back film layer 90 on the side of the binding portion 13 close to the display portion 11 .

[0133] Exemplarily, the display module may further include an adhesive layer 70 disposed between the driving circuit layer 200 and the first back film layer.

[0134] For example, the display module may further include a spacer 300 and a cover layer 400 disposed on the side of the driving circuit layer 200 away from the display. The cover layer 400 may be used to protect the driving circuit layer 200.

[0135] In some embodiments, the bend portion 12 of the display panel 10 is provided with a first protective layer 500 for protecting the bend portion 12. The first protective layer 500 is located on a side of the bend portion 12 away from the display portion 11 and covers the bend portion 12. The first protective layer 500 may be made of an adhesive material or a metal material.

[0136] In the embodiments of the present disclosure, the first back film layer including the double-layer buffer layer + the aluminum heat-conducting layer can also be applied to a large-sized rigid display module or display device.

[0137] Figure 7 This is a structural diagram of a display module according to related art. Figure 8 4 is a schematic structural diagram of a display module according to an embodiment of the present disclosure.

[0138] Generally, the larger the size of a display screen (such as a TV display screen, a notebook display screen, etc.), the higher the impact resistance requirement.

[0139] In the related art, refer to Figure 7 The display module includes a base film 600 between the first back film layer 60 and the display panel 10, and a second protective layer 700 located on the side of the first back film layer 60 away from the display panel 10. For example, the base film may include a 0.135 mm thick PET layer, and the second protective layer 700 may include a 0.05 mm thick stainless steel layer. The first back film layer 60 includes a single buffer layer and a stainless steel layer. The thermal conductive layer 64 and the second protective layer 700 may both be stainless steel layers. Increasing the thickness of the stainless steel layer further enhances the impact resistance of the display module.

[0140] In the embodiments of the present disclosure, referring to Figure 8 , can be replaced by the first back film layer 60 comprising a double buffer layer + aluminum heat conducting layer Figure 7 The first back film layer 60, the bottom film 600 and the second protective layer 700 can be Figure 7 The base film 600 and the second protective layer 700 are the same. The combination of the aluminum heat conductive layer and the stainless steel protective layer can reduce the weight of the display module while ensuring the impact resistance of the display module, which is conducive to achieving a lighter and thinner display module.

[0141] Figure 8 The display module in the embodiment shown uses an aluminum heat conducting layer instead of Figure 7 The partial stainless steel layer in the embodiment shown is conducive to achieving a lighter and thinner display module, while also taking into account the protective effect of the first back film layer on the large-size display panel.

[0142] Optionally, an embodiment of the present disclosure further provides a display device, referring back to Figure 1 The display device 1000 may include the display module 100 described above. Display devices may include, but are not limited to, electronic paper, mobile phones, tablet computers, monitors, laptop computers, digital photo frames, navigation systems, and any other product or component with a display function. It should be understood that this display device has the same beneficial effects as the display modules provided in the aforementioned embodiments.

[0143] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined in the claims and their equivalents.

Claims

1. A display module having a display side and a backlight side disposed opposite to each other, characterized in that: The display module includes: a display panel; and a first back film layer located on the side of the display panel away from the display. Wherein, the first back film layer comprises: a first adhesive layer located on a side of the display panel away from the display; a first buffer layer located on a side of the first adhesive layer away from the display panel; a second bonding layer located on a side of the first buffer layer away from the first bonding layer; a second buffer layer located on a side of the second adhesive layer away from the first buffer layer; and a heat conducting layer located on a side of the second buffer layer away from the second bonding layer, Wherein, under the same compression ratio, the compressive rebound stress value of the first buffer layer is different from the compressive rebound stress value of the second buffer layer.

2. The display module according to claim 1, wherein: At the same compression ratio, the compressive rebound stress value of the first buffer layer is smaller than the compressive rebound stress value of the second buffer layer.

3. The display module according to claim 1, wherein: At the same compression ratio, the compressive rebound stress value of the first buffer layer is greater than the compressive rebound stress value of the second buffer layer.

4. The display module according to any one of claims 1 to 3, wherein: In a direction from the display side to the backlight side, a thickness of the first buffer layer is substantially equal to a thickness of the second buffer layer.

5. The display module according to claim 4, wherein: In the direction from the display side to the backlight side, a ratio of the thickness of the first buffer layer to the thickness of the first adhesive layer is in the range of 2-3; and / or, In a direction from the display side to the backlight side, a ratio of a thickness of the second buffer layer to a thickness of the second adhesive layer is in a range of 2-3.

6. The display module according to claim 5, wherein: In a direction from the display side to the backlight side, the thickness of the first buffer layer is greater than the thickness of the heat conducting layer.

7. The display module according to any one of claims 1 to 3 and 5 to 6, wherein: A plurality of openings are provided on at least one of the first buffer layer and the second buffer layer.

8. The display module according to claim 1, wherein: The material of the first bonding layer includes textured glue; and / or, The material of the first buffer layer includes ultra-clean foam; and / or, The material of the second adhesive layer includes textured glue; and / or, The material of the second buffer layer includes ultra-clean foam; and / or, The material of the heat conducting layer includes aluminum.

9. The display module according to claim 1, wherein: The display module further includes: a second back film layer located between the display panel and the first back film layer; and The driving circuit layer is located on a side of the first back film layer away from the display panel.

10. A display device, characterized in that: The invention comprises a display module as described in any one of claims 1 to 9.

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