Display module and display device

Abstract

The invention provides a display module and a display device. The display module is provided with a display side and a backlight side which are arranged oppositely. The display module comprises a display panel; and the first back film layer is positioned on the display panel far away from the display side. The first back film layer comprises a first bonding layer located on the side, away from the display side, of the display panel. The first buffer layer is located on the side, away from the display panel, of the first bonding layer; the second bonding layer is positioned on one side, far away from the first bonding layer, of the first buffer layer; the second buffer layer is positioned on one side, far away from the first buffer layer, of the second bonding layer; the heat conduction layer is located on the side, away from the second bonding layer, of the second buffer layer, and under the same compression ratio, the compression rebound stress value of the first buffer layer is different from that 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 development of display technology, display devices (such as mobile phones, laptops or tablet computers, etc.) are increasingly used in people's lives. Display devices include display modules. As display devices develop towards the direction of being lighter and thinner, the thickness of display modules is gradually reduced. However, the thinning of display modules can easily lead to problems such as mold marks and reduced impact resistance during the bonding process.

[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 the 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 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 bonding 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, a compressive rebound stress value of the first buffer layer is greater than a 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 bonding 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 disposed 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 bonding 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 comprises a 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 is along Figure 1A schematic cross-sectional view taken along line AA' in FIG.

[0030] Figure 3 It is a schematic structural diagram of the first back film layer in 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 panel of three display modules with different structures during a ball drop test according to an embodiment of the present disclosure;

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

[0035] Figure 8 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] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the 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 size and relative size of the elements may be exaggerated for the purpose of clarity and / or description. Thus, the size and relative size of each element are not necessarily limited to the size and relative size 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, the technical terms or scientific terms used in this disclosure should be understood by ordinary technicians in the field. "First", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0040] In this document, unless otherwise specified, directional terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship based on the drawings, and are only for the convenience of describing the present disclosure, and do not indicate or imply that the device, element or component referred to must have a specific orientation, be constructed or operate in a specific orientation. It should be understood that when the absolute position of the described object changes, the relative positional relationship they represent may also change accordingly. Therefore, these directional terms should not be understood as limiting the present disclosure.

[0041] As used herein, the terms "substantially," "approximately," "approximately," and other similar terms are used as terms of approximation rather than as terms of degree, and they 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. Taking into account factors such as process fluctuations, measurement problems, and errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system), "approximately" or "approximately" as used herein include the stated value and mean that the particular value is within an acceptable range of deviation 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, directional expressions "first direction", "second direction" and "third direction" are used to describe different directions of the display module, for example, the horizontal direction and the vertical direction of the display module. It should be understood that such expressions are only exemplary descriptions and are not limitations of the present disclosure.

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

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

[0045] Compression Force Deformation (CFD): refers to the process in which the molecules inside an object rearrange themselves during deformation, forming an interaction force, which is called compression rebound stress. It gives the object a certain elasticity, and when the external force is removed, the object will return to its original shape. The greater the compression rebound stress, the greater the rebound stress will be after being subjected to compression force.

[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. During point impact, the force-bearing area is smaller and the stress is more concentrated; during surface impact, the force-bearing area is larger and the stress is more dispersed. For example, during the preparation of the module, 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 embossing process will cause a 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, various display terminal manufacturers need to reduce the weight of their products in pursuit of the concept of extremely light and thin products. In recent years, folding display modules have been gradually promoted in the fields of folding mobile phones, curling tablets, folding tablets, etc. At present, the method commonly used for folding display modules is to reduce the thickness of the cover glass (CG for short), which has the most obvious effect. Currently, the thinnest CG on the market is about 0.4mm thick. CG less than 0.4mm cannot meet the requirements of both strength and performance.

[0048] In order to further reduce the weight of the display module, relevant technicians chose to make a thinning solution from the rear support of the screen. At present, the mainstream large-size rear support structure usually uses stainless steel, a material with higher hardness, as the back plate, combined with a single layer of buffer foam to play a supporting role, while meeting the specifications of the falling ball and solving the film printing problem generated during the bonding process. However, the weight of stainless steel is relatively large 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 disposed opposite to each other. The display module includes: a display panel; and a first back film layer located on the display panel away from the display side. Wherein, the first back film layer includes: a first adhesive layer located on the display panel away from the display side; a first buffer layer located on the first adhesive layer away from the display panel side; a second adhesive layer located on the first buffer layer away from the first adhesive layer side; a second buffer layer located on the second adhesive layer away from the first buffer layer side; and a heat conductive layer located on the second buffer layer away from the second adhesive layer side. Wherein, 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 used to improve the impact resistance of the display module, while reducing the weight of the display module, which is conducive to making the display module lighter and thinner.

[0051] Figure 1 is a structural diagram of a display device according to an embodiment of the present disclosure, Figure 2 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 Figure 1 and Figure 2 , a display device 1000 is provided. The display device 1000 includes a display module 100, and the display module has a display side M1 and a backlight side M2 ​​that are arranged opposite to each other. The display module 100 includes a display panel 10, and the display panel 10 is used to display an image. The display side M1 of the display module 100 is the side of the display panel 10 for users to watch, 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 an area on the display panel 10 for displaying images, and the peripheral area NA is an area of ​​the display side of the display panel 10 excluding the display area AA.

[0054] The display area AA may have various shapes. For example, the display area AA may be provided in various shapes such as a polygon (e.g., a rectangle) of a closed shape including straight edges, a circle, an ellipse, etc. including curved edges, and a semicircle, a semi-ellipse, etc. including straight edges and curved edges. In an embodiment of the present disclosure, the display area AA is provided as an area having a rounded rectangular shape including straight edges. It should be understood that this is only an exemplary embodiment of the present disclosure, not a limitation of the present disclosure. The peripheral area NA may be provided on at least one side of the display area AA. In an embodiment of the present disclosure, the peripheral area NA may 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] According to 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, refer to Figure 2 The display panel 10 is a flexible display panel, and includes a display portion 11, a bending portion 12, and a binding portion 13 connected in sequence, and the bending portion 12 is bent so that the binding portion 13 is located on the back of the display panel 10. The back of the display panel 10 is the side opposite to the display side of the display panel 10. That is, the back of the display panel faces the backlight side M2. In the orthographic projection onto the XY plane, the display area AA is located in the display portion 11.

[0058] Exemplarily, 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 farther away from the display unit 11 than the boundary of the bent portion 12 that is farthest from the display unit 11. The cover plate 40 extends on the XY plane, so that the upper surface and the lower surface of the cover plate 40 are parallel to the XY plane. The material of the cover plate 40 can be a transparent material such as acrylic or glass, which is not limited in the embodiment of the present disclosure.

[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 may include at least one of optically clear adhesive (OCA), liquid optically clear adhesive (LOCA), or ultraviolet curing adhesive, but is not limited thereto, and may also be other adhesive materials capable of achieving connection. For example, the connection layer 30 is an optically transparent 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 connection layer 30 and the display panel 10 and has polarization performance. The polarizer 20 is configured to convert the non-polarized 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 weakening the rainbow pattern appearing in the display image of the display panel 10, so as to improve 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 compensatory polarizer, and other types of polarizers, which are not limited in the embodiments of the present disclosure.

[0063] Exemplarily, the display module 100 may further include a first back film layer 60. The first back film layer 60 is located on a side of the display panel 10 away from the display side M1, and can buffer the stress acting on the display panel 10, and can dissipate the heat generated by the display panel 10 when working, thereby providing a certain protection effect on 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 driving circuit layer 200 located on the side of the first back film layer 60 away from the display panel 10. For example, the driving circuit layer 200 may include a rigid printed circuit board 201 (full name in English: Printed Circuit Board, PCB for short), a flexible circuit board 202 (full name in English: Flexible Printed Circuitboard, FPC for short) or a rigid-flexible board. The driving circuit layer 200 is configured to transmit electrical signals to the display panel 10. The driving circuit layer 200 may also include a driving chip 203 (full name in English: Integrated Circuit, IC for short) for providing a control signal to the display panel 10.

[0066] At least a portion of the driving circuit layer 200 (such as a PCB board) needs to be fixedly welded on the backlight side of the display module using a stamping process to achieve electrical connection between some devices or structures in the driving circuit layer 200 and the display panel 10. In the stamping process, a jig needs to be used to apply a certain pressure to the display module. If the impact resistance of the first back film layer is insufficient, it is easy to form a film print on the display module, affecting the display effect.

[0067] Figure 3 It is a schematic structural 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. The stainless steel has a high hardness and can provide good support and impact resistance. The stainless steel can also dissipate heat.

[0070] Exemplarily, 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 play a protective role on the display panel.

[0071] Exemplarily, 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 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 about 0.03 mm, the thickness h2 of the buffer layer 62 is about 0.15 mm, the thickness h3 of the second adhesive layer 63 is about 0.03 mm, and the thickness of the heat conducting layer 64 is about 0.08 mm. The total thickness h0 of the first back film layer 60 in the Z1 direction is about 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] In order to further reduce the weight of the display module, in the embodiment of the present disclosure, a laminated structure including an aluminum layer + a double-layer buffer layer is used to achieve functions such as buffer protection and heat dissipation. The double-layer buffer layer can have different compression rebound stress values, which can have a good buffering effect on both point impact and surface impact, and can make up for the problem of insufficient impact resistance caused by the low hardness of aluminum.

[0076] Figure 4 is a schematic structural diagram 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 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 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 the functions of bonding and venting, 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 the supporting 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 as the heat sink and support plate can significantly reduce the weight of the first back film layer 60 under the same size conditions. For example, using aluminum as the heat conduction layer can reduce the weight of the heat conduction layer by about 65% compared to using stainless steel as the heat conduction layer under the same size, which is conducive to achieving a thinner display module.

[0082] Although the density of aluminum is lower than that of stainless steel, it also has disadvantages. For example, the hardness of aluminum is inferior to that of stainless steel, and the impact resistance of aluminum is not as good as that of stainless steel. Table 1 shows the hardness values ​​of various types of materials (e.g., P1-P7), and the hardness value of each type of material includes 3 measured Vickers hardness values. Referring to Table 1, it can be seen that the average Vickers hardness of the latest super-hard aluminum material P1 is about 84, which is about 35 different from the Vickers hardness of the rolled copper material P6 commonly used in mobile phone displays, and about 201 different from the Vickers hardness of the stainless steel material P7.

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

[0084]

[0085] Using aluminum to replace stainless steel in the first back film layer can easily lead to reduced impact resistance of the first back film layer. In the embodiment of the present disclosure, a double-layer buffer layer (such as 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, thereby ensuring that the first back film layer has good impact resistance, support and heat dissipation functions while achieving a thin and light display module, meeting the customer's drop ball test requirements and avoiding 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 being compressed and deformed.

[0088] Exemplarily, when the first buffer layer 602 and / or the second buffer layer 604 is impacted by the external force F0, a certain degree of compression will occur. For example, the first buffer layer 602 and / or the second buffer layer 604 is compressed to a thickness h200 of 25% or 50% of the initial thickness h100. In this article, 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, the compression ratio is in the range of 20%-30%, the first compressive rebound stress value CFD1 of the first buffer layer 602 is different from the 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 terms of surface impact resistance in the embossing process, wherein the larger the number after L, the stronger the surface impact resistance and the smaller the probability of mold printing; "K1 / K2 / K3" refers to the impact absorption rate of different first back film layers in terms of point impact resistance in a 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, in the drop ball test, a 8.34 g ball is freely dropped from a height of 15 cm 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 printing 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 a 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 the point impact resistance and the 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, refer to Figure 4 , the CFD values ​​of the first buffer layer 602 and the second buffer layer 604 are different.

[0098] By designing two buffer materials with different CFD values ​​in the stacked structure of the first back film layer, the stress generated by different types of impacts (such as point impact or surface impact) can be absorbed, thereby improving the impact resistance of the first back film layer, meeting the customer's drop ball test requirements and avoiding mold printing problems in the stamping process. The double-layer buffer layer can make up for the defects caused by the insufficient hardness of aluminum, ensuring that the impact resistance of the first back film layer meets the requirements while reducing the weight of the first back film layer, which is conducive to the thinness of the display module.

[0099] For example, refer 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] Exemplarily, 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 about 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 about 0.01 MPa, 0.05 MPa or 0.1 MPa. When the compression ratio is about 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 about 0.1 MPa, 0.4 MPa or 0.7 MPa.

[0102] For example, when the compression ratio is about 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 about 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 about 0.3 MPa, 0.5 MPa or 0.7 MPa.

[0103] The first buffer layer 602 has a lower CFD value, and has a better effect of buffering and absorbing surface impact pressure, which can reduce the probability of mold printing in the imprinting process. The second buffer layer 604 has a higher CFD value, and has a better effect of buffering and absorbing point impact pressure, which can meet 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 thinner and lighter display module.

[0105] Exemplarily, 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 about 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 about 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 about 0.01 MPa, 0.05 MPa or 0.1 MPa.

[0107] For example, when the compression ratio is about 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 about 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 about 0.01 MPa, 0.15 MPa or 0.3 MPa.

[0108] The first buffer layer 602 has a higher CFD value, and has a better buffering and absorbing effect on point impact pressure, which can meet the requirements of the drop ball test. The second buffer layer 604 has a lower CFD value, and has a better buffering and absorbing effect on surface impact pressure, which can reduce the probability of mold printing in the embossing 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 thinner and lighter display module.

[0110] In the embodiment of the present disclosure, the double-layer buffer layer can have good buffering and absorption capabilities for point impact pressure and surface impact pressure respectively, ensuring that the first back film layer has good impact resistance for both point impact and surface impact. Compared with the first back film layer comprising a single-layer buffer layer + a stainless steel thermal conductive layer, the first back film layer comprising a double-layer buffer layer + an aluminum thermal conductive layer of the embodiment of the present disclosure has a lower weight and better impact resistance, which can meet the customer's drop ball test requirements and avoid mold printing, which is conducive to realizing the thinness of the display module.

[0111] Exemplarily, 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 about 0.08 mm, and the thickness h14 of the second buffer layer 604 is about 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 bonding layer 601 is in the range of 2 to 3. For example, the thickness h12 of the first buffer layer 602 is about 0.08 mm, and the thickness h11 of the first bonding layer 601 is about 0.03 mm.

[0115] Exemplarily, 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 bonding layer 603 is in the range of 2 to 3. For example, the thickness h14 of the second buffer layer 604 is about 0.08 mm, and the thickness h13 of the second bonding layer 603 is about 0.03 mm.

[0116] Exemplarily, 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 conductive 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 conductive 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. Exemplarily, 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 including a single-layer buffer layer + a stainless steel thermal conductive layer, the total thickness h10 of the first back film layer 60 including 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 It is a simulation comparison diagram of the maximum principal strain generated by the display panel of three display modules with different structures during a ball drop test according to an embodiment of the present disclosure.

[0120] For example, Table 3 shows the structure of display modules of three different schemes, wherein all three schemes include a cover plate 40, a connecting layer 30, a polarizing layer 20, a display panel 10, a second back film layer 50 and a first back film layer 60 stacked in sequence. Among them, the cover plate 40, the connecting layer 30, the polarizing layer 20, the display panel 10 and the second back film layer 50 of the three schemes have basically the same material types and properties, and the thickness is also basically the same. For example, the thickness of the cover plate 40 is about 0.4 mm, the thickness of the connecting layer 30 is about 0.15 mm, the thickness of the polarizer 20 is about 0.105 mm, the thickness of the display panel 10 is about 0.049 mm, and the thickness of the second back film layer 50 is about 0.088 mm. In the embodiment of the present disclosure, three different structures of the first back film layer 60 are designed. Among them, the first back film layer 60 of scheme one includes: 0.03 mm first adhesive layer (such as EMBO) + 0.08 mm first buffer layer (such as WPC Foam) + 0.03 mm second adhesive layer (such as EMBO) + 0.08 mm second buffer layer (such as JPC-B Foam) + 0.05 mm thermal conductive layer (such as aluminum foil). The first back film layer 60 of scheme two includes: 0.03 mm first adhesive layer (such as EMBO) + 0.08 mm first buffer layer (such as JPC-BFoam) + 0.03 mm second adhesive layer (such as EMBO) + 0.08 mm second buffer layer (such as WPC Foam) + 0.05 mm thermal conductive layer (such as aluminum foil). The first back film layer 60 of scheme three includes: 0.03 mm adhesive layer (such as EMBO) + 0.16 mm buffer layer (such as JPC Foam) + 0.05 mm thermal conductive layer (such as aluminum foil).

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

[0122]

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

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

[0125] Combined with reference Figure 6 It can be found from Table 3 that the strain degree of the display panel of the display module using the first back film layer including the double-layer foam structure in the drop ball test is significantly lower than the strain degree of the display panel of the display module using the first back film layer including the single-layer foam structure in the drop ball test. This shows that the use of a double-layer buffer layer with different CFD values ​​in the first back film layer can better absorb the impact force during the drop ball test, reduce the force on the display panel, and thus reduce the strain on the display panel, which can better protect the display panel.

[0126] For example, in some embodiments of the present disclosure, the reference 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 protective effect of the first back film layer on the display panel.

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

[0129] Exemplarily, the display module 100 may further include a third back film layer 90. The third back film layer 90 is disposed on a side of the binding portion 13 close 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 back film layer 50 and the third back film layer 90 may provide support force to the display portion 11 and the binding portion 13 of the display panel 10 to achieve a better bending effect.

[0130] Exemplarily, the materials of the second back film layer 50 and the third back film layer 90 may be the same or different. For example, the materials of the second back film layer 50 and the third back film layer 90 may 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 bending 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 gasket 300 and a cover layer 400 disposed on the driving circuit layer 200 away from the display side. The cover layer 400 may be used to protect the driving circuit layer 200.

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

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

[0137] Figure 7 It is a structural schematic diagram of a display module in the related art. Figure 8 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 bottom 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 bottom film may include a 0.135 mm thick PET layer, and the second protective layer 700 may include a 0.05 mm stainless steel layer. The first back film layer 60 includes a single buffer layer + a stainless steel layer. The heat conductive layer 64 and the second protective layer 700 may both be made of a stainless steel layer, and the thickness of the stainless steel layer may be increased, thereby further improving 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 + an aluminum heat conductive layer Figure 7 The first back film layer 60, the bottom film 600 and the second protective layer 700 can be Figure 7 The bottom film 600 and the second protective layer 700 are the same. The combination design 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 realizing the lightness and thinness of the 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 illustrated embodiment is conducive to realizing a thinner and lighter display module, while taking into account the protective effect of the first back film layer on the large-size display panel.

[0142] Optionally, the embodiment of the present disclosure further provides a display device, referring back to Figure 1 The display device 1000 may include the above-mentioned display module 100. The display device may include but is not limited to: electronic paper, mobile phones, tablet computers, monitors, laptop computers, digital photo frames, navigators, and any other products or components with display functions. It should be understood that the display device has the same beneficial effects as the display module provided in the above-mentioned embodiment.

[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 by the claims and their equivalents.

Claims

1. A display module, the display module having a display side and a backlight side disposed opposite to each other, characterized in that: The display module comprises: a display panel; and a first back film layer located on a 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 bonding 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: Under 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: Under 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, the ratio of the thickness of the first buffer layer to the thickness of the first bonding 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: At least one of the first buffer layer and the second buffer layer is provided with a plurality of openings.

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 bonding 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: Comprising a display module as described in any one of claims 1-9.

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