Back film, display module and display device

Abstract

The invention provides a back film, a display module and a display device, relates to the technical field of display, and can effectively prevent cracks from being pressed near a binding area on a display panel so as to effectively avoid the problem of abnormal display functions such as bright lines after the display panel is pulled. And the display module is more reliable and durable in reliability verification. The back film is applied to the display module and comprises a first adhesive material layer, a base material layer, a second adhesive material layer and a protective layer which are arranged in a stacked mode. Wherein the elastic modulus of the material of the second adhesive material layer is smaller than that of the material of the base material layer, and the elastic modulus of the material of the first adhesive material layer is smaller than or equal to that of the material of the second adhesive material layer.

Description

Technical Field

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

[0002] At present, in the circuit design of display modules, COF (Chip On Flex, or Chip On Film) design is mostly used, that is, the driving chip, also known as the integrated circuit (IC), is bound to the display panel by COF technology during the preparation process of the display module.

[0003] COF technology is an integrated circuit packaging technology, which is a grain soft film assembly technology that fixes the integrated circuit on a flexible circuit board; this technology uses a soft additional circuit board as a packaging chip carrier to combine the chip with a soft substrate circuit, or refers to a soft additional circuit board without a packaged chip. Summary of the invention

[0004] The technical problem solved by the present disclosure is: how to avoid cracks being pressed out near the binding area on the display panel, and the appearance of bright lines and other display function abnormalities.

[0005] On the one hand, a back film is provided, which is applied to a display module, and the back film includes a first adhesive layer, a base material layer, a second adhesive layer and a protective layer which are stacked; wherein the elastic modulus of the material of the second adhesive layer is smaller than the elastic modulus of the material of the base material layer, and the elastic modulus of the material of the first adhesive layer is smaller than or equal to the elastic modulus of the material of the second adhesive layer.

[0006] The beneficial effects of the present disclosure are: the elastic modulus of the material of the first adhesive layer and the elastic modulus of the material of the second adhesive layer are both smaller than the elastic modulus of the material of the substrate layer, and the first adhesive layer and the second adhesive layer are softer, more elastic, and have better stress buffering capabilities than the substrate layer; the first adhesive layer is closer to the display panel than the substrate layer, and when the driving chip and the display panel are bound using the COF technology, a larger pressure applied to the display panel can be transmitted to the first adhesive layer, and the first adhesive layer has a better stress buffering capability, and this part of the pressure can be released through the first adhesive layer, and a small part of the pressure that is not released by the first adhesive layer can be transmitted to the second adhesive layer through the substrate layer, and the second adhesive layer has a better stress buffering capability, and this small part of the pressure can be released through the second adhesive layer, which can effectively prevent cracks from being pressed out near the binding area on the display panel, thereby effectively avoiding the display function abnormality such as bright lines after the display panel is pulled, making the display module more reliable and durable in reliability verification.

[0007] In some embodiments, under the condition of a temperature range of 10° C. to 40° C., the elastic modulus of the material of the first adhesive layer is in a range of 0.05 MPa to 0.5 MPa.

[0008] In some embodiments, under the condition of a temperature range of 10° C. to 40° C., the elastic modulus of the material of the second adhesive layer is in a range of 0.2 MPa to 1 MPa.

[0009] In some embodiments, the thickness of the first adhesive layer ranges from 10 μm to 30 μm.

[0010] In some embodiments, the thickness of the second adhesive layer ranges from 10 μm to 30 μm.

[0011] In some embodiments, the thickness of the first adhesive layer is equal to the thickness of the second adhesive layer.

[0012] In some embodiments, under the condition of a temperature range of 10° C. to 40° C., the elastic modulus of the material of the substrate layer is in the range of 2 GPa to 3 GPa.

[0013] In some embodiments, the thickness of the substrate layer ranges from 25 μm to 75 μm.

[0014] In some embodiments, the elastic modulus of the material of the protective layer is greater than or equal to the elastic modulus of the material of the substrate layer.

[0015] In some embodiments, under the condition of a temperature range of 10° C. to 40° C., the elastic modulus of the material of the protective layer is in a range of 3 GPa to 4 GPa.

[0016] In some embodiments, the thickness of the protective layer ranges from 25 μm to 150 μm.

[0017] On the other hand, a display module is provided, comprising a display panel and the back film as described above, wherein the back film is disposed on the non-display surface side of the display panel, and the first adhesive layer of the back film is attached to the display panel.

[0018] On the other hand, a display module is provided, comprising a display panel and a first adhesive layer and a substrate layer of the back film as described above; the first adhesive layer and the substrate layer are located on the non-display surface side of the display panel, and the first adhesive layer is attached to the display panel.

[0019] In some embodiments, the display module further includes a support plate, and the support plate is located on a side of the substrate layer away from the display panel.

[0020] On the other hand, a display device is provided, comprising the display module as described above and a driving chip, wherein the driving chip is used to drive the display module to display. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required to be used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

[0022] Figure 1 is a cross-sectional view of a display device according to some embodiments;

[0023] Figure 2 is a structural diagram of a corresponding driver chip binding step according to some embodiments;

[0024] Figure 3 is a cross-sectional view of a backing film according to some embodiments;

[0025] Figure 4 is another cross-sectional view of a display device according to some embodiments. DETAILED DESCRIPTION

[0026] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0027] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and other forms thereof, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open, inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0028] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0029] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of the layers and the area of ​​the regions are exaggerated for clarity. Therefore, variations in the shapes relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shapes of the regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0030] For example, Figure 1 As shown, the display device 1000 may include a display module 100 and a driving chip 200 .

[0031] In some embodiments, Figure 1 As shown, the display module 100 may be stacked, and the display module 100 may include a support plate 10, a back film 20, a display panel 30, a polarizer 40, a transparent optical adhesive layer 50 and a cover plate 60 which are stacked in sequence from bottom to top.

[0032] Exemplarily, the display panel 30 can be used to display images; the display panel 30 can be, for example, an organic light-emitting diode (OLED) display panel, a micro organic light-emitting diode (Micro OLED) display panel, a quantum dot light-emitting diode (QLED) display panel, a mini light-emitting diode (Mini LED) display panel or a micro light-emitting diode (Micro LED) display panel, etc., which is not limited in the present disclosure.

[0033] Exemplarily, the display panel 30 may be a flexible display panel or a rigid display panel, which is not limited in the present disclosure.

[0034] For example, Figure 1As shown, the driver chip 200 is connected to the display panel 30 in the display module 100, and the driver chip 200 is configured to provide an electrical signal, such as a control signal, to the display panel 30 in the display module 100. The driver chip 200 can be, for example, a central processing unit, a digital signal processor, a single-chip microcomputer or a programmable logic controller.

[0035] For example, Figure 1 As shown, the polarizer 40, transparent optical adhesive layer 50 and cover plate 60 of the display module 100 are arranged on the display surface A side of the display panel 30, that is, arranged on the light-emitting side of the display panel 30. The polarizer 40 can be used to enhance the contrast and clarity of the image displayed by the display panel 30, and can block unnecessary polarized light, reduce the interference of scattered light and stray light, so that the observer can see a clearer and more vivid image. The cover plate 60 can be, for example, a glass cover plate. The transparent optical adhesive layer 50 is used to attach the cover plate 60 to the polarizer 40.

[0036] For example, Figure 1 As shown, the support plate 10 and the back film 20 of the display module 100 are arranged on the non-display surface B side of the display panel 30 , that is, arranged on the back side of the display panel 30 .

[0037] In some embodiments, Figure 1 As shown, the side of the display panel 30 where the driver chip 200 is located can be bent to the non-display surface B side of the display panel 30 to reduce the width of the frame of the display device 1000, thereby achieving a narrow frame setting. It can be understood that the support plate 10 and the back film 20 located on the non-display surface B side of the display panel 30 are also bent together with the display panel 30.

[0038] Exemplarily, the support plate 10 mainly plays a supporting role, providing certain support for the display panel 30, preventing the display panel 30 from deforming, and enhancing the supporting capacity of the display module 100; the material of the support plate 10 can be, for example, a metal material.

[0039] In some embodiments, the material of the back film 20 may be, for example, PET (Polyethylene terephthalate) material. In other embodiments, the material of the back film 20 may be, for example, PI (Polyimide) material. Both PET material and PI material are flexible materials.

[0040] For example, PET material has low cost and is relatively easy to process, therefore, PET material is used for the back film 20 in most display devices 1000; however, PET material has a relatively large elastic modulus, for example, the elastic modulus of PET material may range from 3 GPa to 4 GPa, and PET material has relatively poor mechanical properties and poor deformation resilience. When the display panel 30 is a folding display panel or a curved display panel, a back film 20 made of PET material is disposed on the non-display surface B of the display panel 30. The poor mechanical properties and poor deformation resilience of the back film 20 may affect the durability of the folding display panel or the curved display panel, and may easily cause problems such as the folding display panel or the curved display panel falling off.

[0041] Exemplarily, the elastic modulus of the PI material is smaller than that of the PET material. For example, the elastic modulus of the PI material may range from 2 GPa to 3 GPa. The PI material has excellent mechanical properties and high tensile strength. Therefore, a back film 20 of the PI material may be provided on the non-display surface B side of the folding display panel or the curved display panel. The back film 20 of the PI material may improve the durability of the folding display panel or the curved display panel, and may prevent the folding display panel or the curved display panel from falling off.

[0042] Among them, the elastic modulus is a physical quantity that describes the elasticity of a material. It represents the stress divided by the strain in the unidirectional stress state. In the elastic deformation stage, the stress and strain of the material are in direct proportion (i.e., they conform to Hooke's law), and the proportional coefficient is called the elastic modulus. The larger the elastic modulus, the stiffer the material, and the smaller the elastic modulus, the softer the material.

[0043] For example, Figure 2 As shown, and refer to Figure 1When the back film 20 of the above-mentioned PI material or the back film 20 of the PET material is set on the non-display surface B of the display panel 30, and the driving chip 200 is bound to the display panel 30 using the COF technology, the driving chip 200 can be set on the chip-on-chip film 1, and the chip-on-chip film 1 can be bound to the display panel 30. During the binding process of the cover chip film 1 and the display panel 30, since the pressure applied by the pressure head on the display panel 30 is relatively large, and the elastic modulus of the PI material and the PET material is relatively large and relatively rigid, this part of the pressure cannot be released through the back film 20 of the PI material or the back film 20 of the PET material. Therefore, during the binding process, cracks will be pressed near the binding area on the display panel 30; and a circuit board, such as a PCB (Printed Circuit Board), is also required to be provided in the display device 1000. During the manufacturing process or transportation and handling process of the display device 1000, the circuit board will inevitably sag due to its thick thickness and heavy weight, causing it to pull the display panel 30. After being pulled, the display panel 30 is very likely to have crack extension, and the crack will continue to extend to the signal line of the display area of ​​the display panel 30, resulting in abnormal display function problems such as bright lines.

[0044] In some embodiments, Figure 3 As shown, and refer to Figure 1 , a back film 20 is provided, which is applied to the display module 100, and the back film 20 includes a first adhesive layer 21, a base material layer 22, a second adhesive layer 23 and a protective layer 24 which are stacked; wherein the elastic modulus of the material of the second adhesive layer 23 is smaller than the elastic modulus of the material of the base material layer 22, and the elastic modulus of the material of the first adhesive layer 21 is smaller than or equal to the elastic modulus of the material of the second adhesive layer 23.

[0045] In some embodiments, Figure 3 As shown, and refer to Figure 1 The back film 20 includes a protective layer 24, a second adhesive layer 23, a base layer 22, and a first adhesive layer 21 stacked in sequence from bottom to top; the second adhesive layer 23 can be used to bond the protective layer 24 to the base layer 22, and the first adhesive layer 21 can be used to bond the base layer 22 to the display panel 30, thereby achieving bonding between the back film 20 and the display panel 30.

[0046] Exemplarily, the protection layer 24 can be used to protect the substrate layer 22 , and can provide support for the substrate layer 22 to prevent the substrate layer 22 from being damaged, thereby improving the manufacturing yield of the display module 100 .

[0047] In some embodiments, the material of the first adhesive layer 21 and the material of the second adhesive layer 23 can be, for example, both organic materials with viscosity, and the elastic modulus of the material of the first adhesive layer 21 and the elastic modulus of the material of the second adhesive layer 23 can be both smaller than the elastic modulus of the material of the substrate layer 22 (for example, PET material or PI material).

[0048] Exemplarily, the elastic modulus of the material of the first adhesive layer 21 is smaller than the elastic modulus of the material of the substrate layer 22. The first adhesive layer 21 is softer, more elastic, and has a better ability to buffer stress than the substrate layer 22. In addition, the first adhesive layer 21 is closer to the display panel 30 than the substrate layer 22. When the driving chip 200 is bound to the display panel 30 using the COF technology, the greater pressure applied to the display panel 30 can be transmitted to the first adhesive layer 21. The first adhesive layer 21 has a better ability to buffer stress. This part of the pressure can be released through the first adhesive layer 21, which can effectively prevent cracks from being pressed out near the binding area on the display panel 30, thereby effectively avoiding the display function abnormalities such as bright lines after the display panel 30 is pulled, making the display module 100 more reliable and durable in trust verification.

[0049] Exemplarily, the elastic modulus of the material of the second adhesive layer 23 is smaller than that of the material of the substrate layer 22, and the second adhesive layer 23 is softer, more elastic, and has a better ability to buffer stress than the substrate layer 22. The small amount of pressure that is not released by the first adhesive layer 21 can be transmitted to the second adhesive layer 23 through the substrate layer 22. The second adhesive layer 23 has a better ability to buffer stress, and the small amount of pressure can be released through the second adhesive layer 23, further effectively preventing cracks from being pressed near the binding area on the display panel 30, thereby effectively avoiding the display function abnormality such as bright lines after the display panel 30 is pulled, making the display module 100 more reliable and durable in reliability verification.

[0050] In some embodiments, the elastic modulus of the material of the first adhesive layer 21 may be less than or equal to the elastic modulus of the material of the second adhesive layer 23 .

[0051] Exemplarily, when the elastic modulus of the material of the first adhesive layer 21 is equal to the elastic modulus of the material of the second adhesive layer 23, the ability of the first adhesive layer 21 to release stress is the same as the ability of the second adhesive layer 23 to release stress. The first adhesive layer 21 cooperates with the second adhesive layer 23 to effectively prevent cracks from being pressed near the binding area on the display panel 30. In addition, the second adhesive layer 23 can also be used to protect the substrate layer 22 to prevent damage to the substrate layer 22.

[0052] Exemplarily, when the elastic modulus of the material of the first adhesive layer 21 is smaller than the elastic modulus of the material of the second adhesive layer 23, the first adhesive layer 21 is softer than the second adhesive layer 23, and the ability of the first adhesive layer 21 to release stress is better than that of the second adhesive layer 23. Most of the pressure applied to the display panel 30 can be released by the first adhesive layer 21 within the first time, and a small part of the pressure that has not been released can be transmitted to the second adhesive layer 23, and the second adhesive layer 23 releases it. The first adhesive layer 21 cooperates with the second adhesive layer 23 to further effectively prevent cracks from being pressed out near the binding area on the display panel 30. In addition, since the second adhesive layer 23 is harder than the first adhesive layer 21, the second adhesive layer 23 can be used to protect the substrate layer 22 and provide certain support for the substrate layer 22 to prevent damage to the substrate layer 22.

[0053] In some embodiments, the elastic modulus of the material of the first adhesive layer 21 is relatively small. For example, the maximum elastic modulus of the material of the first adhesive layer 21 may be 0.03 Mpa. The material of the first adhesive layer 21 is relatively soft, easily deformed, and has relatively weak resilience. When the driving chip 200 is bound to the display panel 30 using the COF technology, the first adhesive layer 21 is easily deformed under a large pressure, so that the area on the first adhesive layer 21 that is subjected to pressure is thinner, and the first adhesive layer 21 has a weak resilience, which makes the first adhesive layer 21 unable to withstand a large pressure, and the ability to release stress is reduced. The pressure applied to the display panel 30 cannot be released in time, thereby pressing cracks near the binding area on the display panel 30; and, since the temperature is high when the driving chip 200 is bound to the display panel 30 using the COF technology, the material of the softer first adhesive layer 21 will be more soft under the influence of the high temperature, and a large amount of glue overflow will occur, so that the material of the first adhesive layer 21 is adhered to some film layers of the display panel 30. When the temperature returns to room temperature, for example, when the temperature returns to 10°C to 40°C, the material of the first adhesive layer 21 will cause cracks in some film layers (such as inorganic insulating film layers) of the display panel 30 adhered to it, thereby reducing the manufacturing yield of the display module 100.

[0054] Therefore, in some embodiments, under the condition that the temperature ranges from 10° C. to 40° C., the elastic modulus of the material of the first adhesive layer 21 ranges from 0.05 MPa to 0.5 MPa.

[0055] Exemplarily, at room temperature, the elastic modulus of the material of the first adhesive layer 21 ranges from 0.05 MPa to 0.5 MPa, and the approximate range of room temperature can be, for example, 10°C to 40°C. For example, the room temperature can be 10°C, 15°C, 20°C, 25°C, 30°C, 35°C or 40°C, etc., which is not limited in the present disclosure.

[0056] Illustratively, at room temperature, the elastic modulus of the material of the first adhesive layer 21 may be, for example, 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa or 0.5 MPa, etc., which is not limited in the present disclosure.

[0057] Exemplarily, at room temperature, the elastic modulus of the material of the first adhesive layer 21 is in the range of 0.05MPa to 0.5MPa, and the elastic modulus of the material of the first adhesive layer 21 is greater than the maximum elastic modulus of 0.03Mpa of the material of the first adhesive layer 21 in the above embodiment. In this way, the flexibility and rigidity of the first adhesive layer 21 are more suitable for the back film 20, and the phenomenon of glue overflow due to high temperature when the driving chip 200 is bound to the display panel 30 using the COF technology can be effectively avoided. Moreover, it is not easy to deform under the application of pressure, has good resilience and high stress release ability. When the driving chip 200 is bound to the display panel 30 using the COF technology, the large pressure applied to the display panel 30 can be transmitted to the first adhesive layer 21, and this part of the pressure can be released through the first adhesive layer 21, which can effectively prevent cracks from being pressed out near the binding area on the display panel 30, thereby avoiding the display function abnormality such as bright lines after the display panel 30 is pulled, making the display module 100 more reliable and durable in trust verification.

[0058] In some embodiments, under the condition that the temperature ranges from 10° C. to 40° C., the elastic modulus of the material of the second adhesive layer 23 ranges from 0.2 MPa to 1 MPa.

[0059] Exemplarily, when the temperature is 10°C, 15°C, 20°C, 25°C, 30°C, 35°C or 40°C, the elastic modulus of the material of the second adhesive layer 23 can be, for example, 0.2MPa, 0.25MPa, 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa, 0.5MPa, 0.55MPa, 0.6MPa, 0.65MPa, 0.7MPa, 0.75MPa, 0.8MPa, 0.85MPa, 0.9MPa, 0.95MPa or 1MPa, etc., and the present disclosure is not limited thereto.

[0060] At room temperature, the elastic modulus of the material of the second adhesive layer 23 is in the range of 0.2MPa to 1MPa, and the elastic modulus of the material of the first adhesive layer 21 is greater than the maximum elastic modulus of 0.03Mpa of the material of the first adhesive layer 21 in the above embodiment. In this way, the flexibility and rigidity of the second adhesive layer 23 are more suitable for the back film 20, and the phenomenon of adhesive overflow due to high temperature when the driving chip 200 and the display panel 30 are bound by the COF technology can be effectively avoided; and it is not easy to deform under the application of pressure, and the resilience performance is good. When the driving chip 200 and the display panel 30 are bound by the COF technology, the stress that is not released by the first adhesive layer 21 can be released by the second adhesive layer 23, which can effectively prevent cracks from being pressed near the binding area on the display panel 30, thereby avoiding the display function abnormality such as bright lines after the display panel 30 is pulled, making the display module 100 more reliable and durable in trust verification.

[0061] Exemplarily, the elastic modulus of the material of the second adhesive layer 23 can be larger than the elastic modulus of the material of the first adhesive layer 21, that is, the second adhesive layer 23 can be relatively rigid compared to the first adhesive layer 21. While releasing the stress that has not been released by the first adhesive layer 21, the second adhesive layer 23 can also provide protection for the substrate layer 22 and provide certain support for the substrate layer 22 to avoid damage to the back film 20 due to insufficient support of the substrate layer 22.

[0062] Exemplarily, the elastic modulus of the material of the second adhesive layer 23 can also be approximately equal to the elastic modulus of the material of the first adhesive layer 21, so that the softness of the second adhesive layer 23 is approximately consistent with that of the first adhesive layer 21. The second adhesive layer 23 can release the stress that has not been released by the first adhesive layer 21 to a larger extent, and can effectively prevent cracks from being pressed near the binding area on the display panel 30, thereby avoiding display function abnormalities such as bright lines after the display panel 30 is pulled, making the display module 100 more reliable and durable in trust verification.

[0063] In some embodiments, the thickness of the first adhesive layer 21 is in the range of 10 μm to 30 μm.

[0064] Exemplarily, the thickness of the first adhesive layer 21 may be, for example, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm, etc., which is not limited in the present disclosure.

[0065] Exemplarily, the thickness of the first adhesive layer 21 is in the range of 10 μm to 30 μm, which can ensure that the first adhesive layer 21 has appropriate viscosity, so that the display panel 30 and the substrate layer 22 are firmly attached, and it is not easy for the display panel 30 or the substrate layer 22 to fall off or be misaligned. In addition, the first adhesive layer 21 is not easy to deform when subjected to a certain pressure. The first adhesive layer 21 has sufficient stress release ability. When the driving chip 200 is bound to the display panel 30 using the COF technology, the pressure applied to the display panel 30 can be released in time. , so as to effectively avoid pressing cracks near the binding area on the display panel 30; at the same time, the thickness of the first glue layer 21 in the range of 10μm to 30μm can effectively prevent the phenomenon of glue overflow. For example, when the first glue layer 21 is too thick, more material is required for the first glue layer 21. When the temperature is high when the COF technology is used to bind the driver chip 200 to the display panel 30, the material of the first glue layer 21 becomes soft under the influence of the high temperature, and part of the more material will overflow, thereby causing glue overflow.

[0066] In some embodiments, the thickness of the second adhesive layer 23 is in the range of 10 μm to 30 μm.

[0067] Exemplarily, the thickness of the second adhesive layer 23 may be, for example, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm, etc., which is not limited in the present disclosure.

[0068] Exemplarily, the thickness of the second adhesive layer 23 is in the range of 10 μm to 30 μm, which can ensure that the second adhesive layer 23 has appropriate viscosity, so that the protective layer 24 and the substrate layer 22 are firmly attached, and it is not easy for the protective layer 24 or the substrate layer 22 to fall off or be misaligned. In addition, the second adhesive layer 23 is not easy to deform when subjected to a certain pressure. The second adhesive layer 23 has a certain ability to release stress. When the driving chip 200 is bound to the display panel 30 using the COF technology, the stress not released by the first adhesive layer 21 can be released by the second adhesive layer. 23 is released, which effectively avoids pressing cracks near the binding area on the display panel 30; at the same time, the thickness of the second glue layer 23 in the range of 10μm to 30μm can effectively prevent the phenomenon of glue overflow. For example, when the second glue layer 23 is too thick, more material of the second glue layer 23 is required. When the COF technology is used to bind the driver chip 200 to the display panel 30 at a high temperature, the material of the second glue layer 23 becomes soft under the influence of the higher temperature, and part of the more material will overflow, thereby causing glue overflow.

[0069] In some embodiments, the thickness of the first adhesive layer 21 may be equal to the thickness of the second adhesive layer 23. This configuration makes the thickness of some film layers of the back film 20 consistent, increases the thickness uniformity of the back film 20, simplifies the preparation process, and saves costs.

[0070] In some embodiments, under the condition of a temperature range of 10° C. to 40° C., the elastic modulus of the material of the substrate layer 22 is in a range of 2 GPa to 3 GPa.

[0071] Exemplarily, when the temperature is 10°C, 15°C, 20°C, 25°C, 30°C, 35°C or 40°C, the elastic modulus of the material of the substrate layer 22 can be, for example, 2 GPa, 2.1 GPa, 2.2 GPa, 2.3 GPa, 2.4 GPa, 2.5 GPa, 2.6 GPa, 2.7 GPa, 2.8 GPa, 2.9 GPa or 3 GPa, etc., and the present disclosure is not limited here.

[0072] For example, the material of the substrate layer 22 may be a PI material, or other materials or a combination of materials with an elastic modulus of 2 GPa to 3 GPa, which is not limited in the present disclosure. The substrate layer 22 is used to protect the display panel 30, provide support for the display panel 30, and block water vapor in the air to prevent water vapor in the air from entering the display panel 30.

[0073] Exemplarily, when the material of the substrate layer 22 is PI material, the substrate layer 22 has excellent mechanical properties and high tensile strength. Therefore, the back film 20 composed of the substrate layer 22 can be arranged on the non-display surface B side of the folding display panel or the curved display panel, so as to be applied to the folding display product or the curved display product. The substrate layer 22 of PI material can improve the durability of the folding display panel or the curved display panel, and can avoid problems such as the folding display panel or the curved display panel falling off.

[0074] In some embodiments, the thickness of the substrate layer 22 may range from 25 μm to 75 μm.

[0075] Illustratively, the thickness of the substrate layer 22 may be 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm or 75 μm, etc., which is not limited in the present disclosure.

[0076] Exemplarily, the thickness of the substrate layer 22 in the range of 25 μm to 75 μm can ensure that the substrate layer 22 has suitable supporting properties, thereby providing effective support for the display panel 30; at the same time, the thickness of the substrate layer 22 in the range of 25 μm to 75 μm can also make the substrate layer 22 have a suitable thickness, realize the flexible design and thin design of the display module 100, and when the substrate layer 22 is laser cut, the laser can completely cut the substrate layer 22 to avoid affecting the substrate layer 22.

[0077] In some embodiments, the elastic modulus of the material of the protection layer 24 is greater than or equal to the elastic modulus of the material of the substrate layer 22 .

[0078] For example, the material of the protection layer 24 may be more rigid than that of the substrate layer 22 , and the protection layer 24 may provide better support for the substrate layer 22 , and better protect the substrate layer 22 .

[0079] In some embodiments, under the condition of a temperature range of 10° C. to 40° C., the elastic modulus of the material of the protection layer 24 is in a range of 3 GPa to 4 GPa.

[0080] Exemplarily, when the temperature is 10°C, 15°C, 20°C, 25°C, 30°C, 35°C or 40°C, the elastic modulus of the material of the protective layer 24 can be, for example, 3 GPa, 3.1 GPa, 3.2 GPa, 3.3 GPa, 3.4 GPa, 3.5 GPa, 3.6 GPa, 3.7 GPa, 3.8 GPa, 3.9 GPa or 4 GPa, etc., which is not limited in the present disclosure.

[0081] For example, the material of the protective layer 24 can be PET material, or other materials or a combination of materials with an elastic modulus in the range of 3 GPa to 4 GPa, which is not limited in the present disclosure. The protective layer 24 is used to protect the substrate layer 22 and provide support for the substrate layer 22.

[0082] In some embodiments, the thickness of the protection layer 24 is in the range of 25 μm to 150 μm.

[0083] Exemplarily, the thickness of the protective layer 24 can be 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm or 150μm, etc., which is not limited to the present disclosure.

[0084] In some embodiments, Figure 3As shown, the back film 20 includes a first adhesive layer 21, a substrate layer 22, a second adhesive layer 23 and a protective layer 24 which are stacked; the elastic modulus of the material of the first adhesive layer 21 ranges from 0.05MPa to 0.5MPa, and the thickness of the first adhesive layer 21 ranges from 10μm to 30μm; the elastic modulus of the material of the substrate layer 22 ranges from 2GPa to 3GPa, and the thickness of the substrate layer 22 ranges from 25μm to 75μm; the elastic modulus of the material of the second adhesive layer 23 ranges from 0.2MPa to 1MPa, and the thickness of the second adhesive layer 23 ranges from 10μm to 30μm; the elastic modulus of the material of the protective layer 24 ranges from 3GPa to 4GPa, and the thickness of the protective layer 24 ranges from 25μm to 150μm. The display module 100 including the back film 20 can be subjected to a drop ball and pen test. The drop ball and pen test comparison table is shown in the following table.

[0085]

[0086] For example, the weight of the ball is 65 g. The structure of the back film 20 is as follows: Figure 1 As shown, the back film 20 is called the back film of PI material. When a ball falls on the flat area of ​​the display module 100 including the PI material back film, the height of the falling ball is 30cm to 45cm. When the height of the falling ball is greater than 45cm, the display module 100 will be damaged; when a ball falls on the bending area of ​​the display module 100 including the PI material back film, the height of the falling ball is 15cm to 25cm. When the height of the falling ball is greater than 25cm, the display module 100 will be damaged. The structure of the back film 20 is as shown in FIG. Figure 3 As shown, the back film 20 is called the back film of the present disclosure. When a ball falls on the flat area of ​​the display module 100 including the back film of the present disclosure, the height of the falling ball is greater than 60 cm; when the ball falls on the bending area of ​​the display module 100 including the back film of the present disclosure, the height of the falling ball is greater than 30 cm.

[0087] For example, the structure of the back film 20 is as follows: Figure 1 As shown, when the pen falls on the flat area of ​​the display module 100 including the PI material back film, the height of the pen is 30cm to 60cm. When the height of the ball is greater than 60cm, the display module 100 will be damaged; when the pen falls on the bending area of ​​the display module 100 including the PI material back film, the height of the pen is 15cm to 35cm. When the height of the ball is greater than 35cm, the display module 100 will be damaged. The structure of the back film 20 is as shown in FIG. Figure 3 As shown, when the pen falls on the flat area of ​​the display module 100 including the back film of the present disclosure, the height of the pen is greater than 60 cm; when the pen falls on the bending area of ​​the display module 100 including the back film of the present disclosure, the height of the pen is greater than 30 cm.

[0088] As can be seen from the above, the back film 20 provided in the embodiment of the present disclosure improves the pressure-bearing capacity of the display module 100, that is, the back film 20 provided in the embodiment of the present disclosure can withstand greater pressure. Therefore, the back film 20 provided in the embodiment of the present disclosure can release the pressure applied to the display panel 30 by the first adhesive layer 21 in the first time, and a small part of the pressure that is not released can be transmitted to the second adhesive layer 23, and the second adhesive layer 23 releases it. The first adhesive layer 21 cooperates with the second adhesive layer 23 to effectively prevent cracks from being pressed near the binding area on the display panel 30, thereby effectively avoiding the display function abnormality such as bright lines after the display panel 30 is pulled, making the display module 100 more reliable and durable in trust verification.

[0089] On the other hand, a display module 100 is provided. Figure 1 As shown, and refer to Figure 3 , including a display panel 30 and the back film 20 as described above, the back film 20 is arranged on the non-display surface B side of the display panel 30, and the first adhesive layer 21 of the back film 20 is attached to the display panel 30.

[0090] For example, when the driving chip 200 is bound to the display panel 30 using the COF technology, the greater pressure applied to the display panel 30 can be transmitted to the back film 20, and this part of the pressure can be released through the back film 20, which can effectively prevent cracks from being pressed out near the binding area on the display panel 30, thereby avoiding display function abnormalities such as bright lines after the display panel 30 is pulled, making the display module 100 more reliable and durable in trust verification.

[0091] In another aspect, the embodiment of the present disclosure also provides another display module 100, such as Figure 4 As shown, it includes a display panel 30 and a first adhesive layer 21 and a substrate layer 22 of the back film 20 as described above; the first adhesive layer 21 and the substrate layer 22 are located on the non-display surface B side of the display panel 30, and the first adhesive layer 21 is attached to the display panel 30.

[0092] Exemplarily, the back film 20 includes a first adhesive layer 21, a base material layer 22, a second adhesive layer 23 and a protective layer 24. When binding the driver chip 200, it can effectively prevent cracks from being pressed out near the binding area on the display panel 30, thereby avoiding display function abnormalities such as bright lines after the display panel 30 is pulled, making the display module 100 more reliable and durable in trust verification.

[0093] After the driver chip 200 is bound, the second adhesive layer 23 and the protective layer 24 in the back film 20 are removed, so that the thickness of the display module 100 can be reduced to achieve a thin design; at the same time, the elastic modulus of the materials of the first adhesive layer 21 and the substrate layer 22 is small, and they have excellent mechanical properties and high tensile strength. Therefore, the first adhesive layer 21 and the substrate layer 22 can be arranged on the non-display surface B side of the folding display panel or the curved display panel, so as to be applied to the folding display product or the curved display product. The first adhesive layer 21 and the substrate layer 22 can improve the durability of the folding display panel or the curved display panel, and can avoid problems such as the folding display panel or the curved display panel falling off.

[0094] In some embodiments, Figure 4 As shown, the display module 100 further includes a support plate 10 , and the support plate 10 is located on a side of the substrate layer 22 away from the display panel 30 .

[0095] Exemplarily, the support plate 10 is disposed on a side of the back film 20 away from the display panel 30 , and the support plate 10 provides support for the display module 100 to ensure the stability and safety of the structure of the display module 100 .

[0096] On the other hand, Figure 1 and Figure 4 As shown, a display device 1000 is provided, comprising the display module 100 and a driving chip 200 as described above, wherein the driving chip 200 is used to drive the display module 100 to display.

[0097] Exemplarily, the display device 1000 may be any device that displays either moving (e.g., video) or fixed (e.g., still images), and whether text or images. The display device 1000 includes, but is not limited to, a television, a mobile phone, a wearable device, a personal digital assistant (PDA), an augmented reality (AR) device, a virtual reality (VR) device, a handheld or portable computer, a GPS receiver / navigator, a camera, an MP4 video player, a camcorder, a game console, a clock, a calculator, a television monitor, a flat panel display, a computer monitor, an in-vehicle display (e.g., an odometer display, etc.), a navigator, a cockpit controller and / or display, a display of a camera view (e.g., a display of a rear-view camera in a vehicle), an electronic photograph, an electronic billboard or sign, a projector, a building structure, a packaging, and an aesthetic structure (e.g., a display of an image of a piece of jewelry), etc.

[0098] In some embodiments, the driver chip 200 may include a memory and a power module, etc., and realize power supply and signal input and output functions through additionally provided wires, signal lines, etc.

[0099] In other embodiments, the driver chip 200 may also include hardware circuits and computer executable codes, etc. The hardware circuits may include conventional very large scale integration (VLSI) circuits or gate arrays and existing semiconductors or other discrete components such as logic chips and transistors; the hardware circuits may also include field programmable gate arrays, programmable array logic, programmable logic devices, etc.

[0100] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0101] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A back film, applied to a display module, characterized in that: include: A first adhesive layer, a base material layer, a second adhesive layer and a protective layer are stacked; The elastic modulus of the material of the second adhesive layer is smaller than the elastic modulus of the material of the base material layer, and the elastic modulus of the material of the first adhesive layer is smaller than or equal to the elastic modulus of the material of the second adhesive layer.

2. The backing film according to claim 1, characterized in that: Under the condition that the temperature ranges from 10° C. to 40° C., the elastic modulus of the material of the first adhesive layer ranges from 0.05 MPa to 0.5 MPa.

3. The backing film according to claim 1 or 2, characterized in that: Under the condition that the temperature ranges from 10° C. to 40° C., the elastic modulus of the material of the second adhesive layer ranges from 0.2 MPa to 1 MPa.

4. The backing film according to claim 1 or 2, characterized in that: The thickness of the first adhesive layer is in the range of 10 μm to 30 μm.

5. The backing film according to claim 1 or 2, characterized in that: The thickness of the second adhesive layer is in the range of 10 μm to 30 μm.

6. The backing film according to claim 1 or 2, characterized in that: The thickness of the first adhesive layer is equal to the thickness of the second adhesive layer.

7. The backing film according to claim 1 or 2, characterized in that: Under the condition of a temperature range of 10° C. to 40° C., the elastic modulus of the material of the substrate layer is in the range of 2 GPa to 3 GPa.

8. The backing film according to claim 1 or 2, characterized in that: The thickness of the substrate layer is in the range of 25 μm to 75 μm.

9. The backing film according to claim 1 or 2, characterized in that: The elastic modulus of the material of the protective layer is greater than or equal to the elastic modulus of the material of the substrate layer.

10. The backing film according to claim 1 or 2, characterized in that: Under the condition of a temperature range of 10° C. to 40° C., the elastic modulus of the material of the protective layer is in the range of 3 GPa to 4 GPa.

11. The backing film according to claim 1 or 2, characterized in that: The thickness of the protective layer ranges from 25 μm to 150 μm.

12. A display module, characterized in that: include: Display panel; The back film according to any one of claims 1 to 11, wherein the back film is disposed on a non-display surface side of the display panel, and the first adhesive layer of the back film is attached to the display panel.

13. A display module, characterized in that: include: Display panel; The first adhesive layer and the substrate layer of the backing film according to any one of claims 1 to 11; The first adhesive layer and the base material layer are located on the non-display surface side of the display panel, and the first adhesive layer is attached to the display panel.

14. The display module according to claim 13, characterized in that: It also includes a support plate, which is located at a side of the substrate layer away from the display panel.

15. A display device, characterized in that: include: The display module according to claim 13 or 14; A driving chip is used to drive the display module to display.

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