Display module

Abstract

The invention relates to a display module. The display module comprises a display panel and a protective film arranged on the light emitting side of the display panel. The protective film comprises a first coating, the thickness D1 of the first coating is monotonically decreased relative to the refractive index n1 of the first coating, D1 and n1 meet the following relational expression I: # imgabs0 #, k is a constant larger than 0, and theta1 is the incident angle of incident light emitted to the surface of the first coating; the display module has various protective films with different refractive indexes and different thicknesses for replacement, when the refractive index n1 and the thickness D1 of the first coating meet the relational expression I, the protective film can be matched with the original optical design of the display module, and the optical related problems occurring after the protective film of an existing display module is replaced are avoided.

Description

Technical Field

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

[0002] With the progress of society and the development of science and technology, people's lives and work are inseparable from smart terminals, and foldable products that are easy to carry and have large screen functions have emerged. When using foldable products, consumers hope to replace the protective film in order to better protect the screen from scratches or damage, or when the original protective film is damaged. However, the replacement of the protective film of the foldable screen is currently carried out by the terminal's after-sales service, and there is often only one type of protective film (the same as the original protective film) to choose from. It is impossible to choose protective films of various thicknesses and functions like straight screens, and consumers are not even recommended to replace them themselves. This is because the terminal has already used the protective film as a fixed part of the screen during the design process, and has made design matching in terms of optics, mechanics, etc. Consumers may encounter optical problems when replacing it by themselves, thus affecting the user experience. Summary of the invention

[0003] An embodiment of the present application provides a display module. The protective film of the display module of the present application can match the original optical design of the display module, thereby avoiding optical-related problems that occur after the protective film of the display module is replaced.

[0004] In order to achieve the above object, the present application provides a display module, the display module comprising:

[0005] display panel; and

[0006] A protective film is disposed on the light-emitting side of the display panel, the protective film comprises a first coating layer, and a thickness D1 of the first coating layer decreases monotonically with respect to a refractive index n1 of the first coating layer;

[0007] D1 and n1 satisfy the following relationship I:

[0008]

[0009] Wherein, k is a constant greater than 0, and θ1 is the incident angle of the incident light incident on the surface of the first coating.

[0010] In some embodiments, k satisfies the following relation II:

[0011]

[0012] Wherein, n0 is the preset refractive index, and D0 is the preset thickness.

[0013] In some embodiments, the incident angle θ1 has a preset range, and the preset range is between 0° and 60°.

[0014] In some embodiments, the preset range has a maximum value, and the incident angle θ1 is equal to the maximum value.

[0015] In some embodiments, the refractive index n1 of the first coating layer is in the range of 1.3≤n1≤1.8, and the thickness D1 of the first coating layer is in the range of 0 μm<D1≤100 μm.

[0016] In some embodiments, the preset refractive index n0 is in a range of 1.3≤n0≤1.8, and the preset thickness D0 is in a range of 0 μm<D0≤100 μm.

[0017] In some embodiments, a distance d1 between a position where the incident light passes through the protective film and reaches the surface of the display panel and a normal line corresponding to the incident light is equal to a preset distance d0.

[0018] In some embodiments, the display module further includes a camera, the display panel includes a camera area, and the camera is located on a side of the display panel away from the protective film and corresponds to the camera area;

[0019] The distance d1' between the position where the incident light passes through the protective film and reaches the surface of the imaging area and the normal line corresponding to the incident light is equal to the preset distance d0'.

[0020] In some embodiments, the protective film further includes a first substrate layer, and the first substrate layer is located on a side of the first coating layer close to the display panel;

[0021] The refractive index of the first substrate layer is equal to a first preset value, and the thickness of the first substrate layer is equal to a second preset value.

[0022] In some embodiments, the material of the first coating layer includes at least one of an acrylate compound or an epoxy resin compound;

[0023] The material of the first substrate layer includes at least one of polyethylene terephthalate, polypropylene, polymethyl methacrylate, polycarbonate, triacetyl cellulose, transparent polyimide, and ultra-thin flexible glass.

[0024] The present application provides a display module, the display module includes a protective film, the protective film is a replaceable protective film suitable for foldable products, including a first coating, the thickness D1 of the first coating decreases monotonically with respect to the refractive index n1 of the first coating, that is, D1 decreases as n1 increases, and D1 and n1 satisfy the relationship I. When D1 and n1 of the selected protective film satisfy the relationship I, the optical path of the incident light after passing through the protective film can be made the same as the original optical path of the display module, so that the original optical design of the protective film and the display module are matched. Therefore, the display module of the present application has a variety of protective films with different refractive indices and different thicknesses for replacement, and can ensure that the replaced protective film matches the original optical design of the display module, avoiding the optical-related problems that occur after the protective film of the existing foldable products is replaced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a structural schematic diagram of a display module provided in an embodiment of the present application;

[0026] Figure 2 It is a structural schematic diagram of a display module provided by the prior art;

[0027] Figure 3 It is a schematic diagram comparing the optical path of the incident light through the second coating layer of the original protective film and the optical path of the first coating layer of the protective film of the present application.

[0028] Description of reference numerals:

[0029] 10. Display module; 110. Protective film; 111. First coating layer; 112. First substrate layer; 113. First bonding layer; 120. Original protective film; 121. Second coating layer; 122. Second substrate layer; 123. Second bonding layer; 200. Display panel; 201. Opening; 210. Flexible display layer; 220. Cover layer; 230. Back layer; 240. Support layer; 250. Optical adhesive layer; 260. Adhesive layer; 270. Dust-proof film; 300. Camera. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0031] In the prior art, the protective film of the foldable display module usually includes a hard coating of organic material, which has the functions of improving hardness, friction resistance, and anti-fingerprint. However, changes in the refractive index and thickness of the hard coating usually have a significant impact on the optical properties of the display module. When the refractive index and thickness of the hard coating change, the optical path of the incident light in the hard coating changes, which will correspondingly cause the position of the incident light reaching the display panel through the hard coating to change, and it cannot match the original optical design of the display module, thereby causing optical-related problems, such as out-of-focus shooting and affecting the screen reflectivity.

[0032] To solve the above problems, the present application provides a display module 10. Figure 1 The display module 10 includes a display panel 200 and a protective film 110. The protective film 110 can be used to replace the original protective film of the existing display module to solve the optical problems that occur after the protective film of the display module is replaced.

[0033] The display panel 200 includes a flexible display layer 210, a cover layer 220, a back layer 230 and a support layer 240. Specifically, the cover layer 220 is located between the flexible display layer 210 and the protective film 110, and is used to protect the flexible display layer 210; the back layer 230 is located on the side of the flexible display layer 210 away from the cover layer 220, and is used to support the flexible display layer 210; the support layer 240 is located on the side of the back layer 230 away from the flexible display layer 210, and is used to support the film layer above it. Further, an optical adhesive layer (OCA) 250 is also included between the cover layer 220 and the flexible display layer 210; an adhesive layer 260, such as a pressure-sensitive adhesive (PSA), is also included between the support layer 240 and the back layer 230; and a dustproof film 270 is also included on the side of the support layer 240 away from the back layer 230. Wherein, the flexible display layer 210 can be an OLED, but is not limited thereto.

[0034] The protective film 110 is disposed on the light-emitting side of the display panel 200 . The protective film 110 includes a first coating layer 111 . The thickness D1 of the first coating layer 111 decreases monotonically with respect to the refractive index n1 of the first coating layer 111 . D1 and n1 satisfy the following relational expression I:

[0035]

[0036] Wherein, k is a constant greater than 0, and θ1 is the incident angle of the incident light incident on the surface of the first coating layer 111 .

[0037] The display module 10 of the present application has a variety of protective films 110 with different refractive indices and different thicknesses for replacement, and the thickness D1 of the first coating layer of the protective film 110 decreases as the refractive index n1 of the first coating layer increases. When D1 and n1 of the selected protective film 110 satisfy the relationship I, it can be ensured that the replaced protective film 110 matches the original optical design of the display module, thereby avoiding optical-related problems that occur after the protective film of the existing foldable products is replaced.

[0038] Furthermore, k satisfies the following relation II:

[0039]

[0040] Wherein, n0 is the preset refractive index, and D0 is the preset thickness.

[0041] By combining the above formula I and formula II, and sorting out the combined relationship, the following relationship III is obtained:

[0042]

[0043] Wherein, n0 is a preset refractive index, D0 is a preset thickness, and θ1 is an incident angle of the incident light incident on the surface of the first coating 111 .

[0044] In the present application, the preset refractive index n0 and the preset thickness D0 may be the optimal refractive index value and optimal thickness value of the protective film that matches the original optical design of the existing display module, or the industry's standard reference value, etc., but are not limited thereto.

[0045] In some embodiments, the preset refractive index n0 and the preset thickness D0 may be the refractive index and thickness of the original protective film of the existing display module, that is, the refractive index of the original protective film of the existing display module is n0, and the thickness is D0. The original protective film may be the original protective film of the existing display module when it leaves the factory, or the old protective film attached to the existing display module before replacing the new protective film.

[0046] For details, please refer to Figure 2 , Figure 2 The structure diagram of a display module provided by the prior art is shown in FIG. The prior art display module includes a display panel 200 and an original protective film 120 located on the light-emitting side of the display panel 200, the original protective film 120 includes a second coating 121, the refractive index of the second coating 121 is n0, and the thickness of the second coating 121 is D0.

[0047] See also Figure 1The protective film 110 of the present application can be used to replace the original protective film 120. The protective film 110 of the present application includes a first coating layer 111. The refractive index n1 and thickness D1 of the first coating layer 111 satisfy the following relationship:

[0048]

[0049] Wherein, n0 is a preset refractive index, D0 is a preset thickness, and θ1 is an incident angle of the incident light incident on the surface of the first coating 111 .

[0050] It should be noted that the display panel 200 of the display module 10 of the present application has the same structure as the display panel 200 of the existing display module. Figure 1 and Figure 2 The display module structures shown are different only in the protective film.

[0051] When the refractive index n1 and thickness D1 of the first coating layer 111 of the protective film 110, the refractive index n0 and thickness D0 of the second coating layer 121 of the original protective film 120, and the incident angle θ1 of the incident light satisfy equation III, the replaced protective film 110 can be matched with the original optical design of the display module, thereby avoiding optical-related problems that may occur after the protective film of the existing display module is replaced.

[0052] It can be understood that in the present application, θ1, D0, and n0 are all known values, and Formula III is the relationship between D1 and n1. Multiple sets of D1 and n1 values ​​can be obtained through Formula III, that is, the display module 10 of the present application has a variety of protective films 110 with different refractive indices and different thicknesses available for replacement. When D1 and n1 of the selected protective film 110 satisfy Formula I, the optical path of the incident light after passing through the protective film 110 can be made the same as the original optical path of the display module, thereby achieving the original optical design matching of the protective film 110 with the display module.

[0053] See also Figure 3 , Figure 3 It is a schematic diagram comparing the optical path of the second coating layer 121 of the original protective film 120 and the optical path of the first coating layer 111 of the protective film 110 of the present application.

[0054] in, Figure 3In a, a is a schematic diagram of the optical path of the second coating 121, the incident light L1 is incident from the first surface K1 of the second coating 121 (K1 is the surface of the second coating 121 away from the display panel 200) to the inside of the second coating 121, the incident angle of the incident light L1 is θ1, that is, the angle between the incident light L1 and its corresponding normal N1 is θ1, the incident light L1 enters the inside of the second coating 121 and is refracted to form a first refracted light L2, the refraction angle of the first refracted light L2 is θ2, the first refracted light L2 is emitted from the second surface K2 of the second coating 121 (K2 is the surface of the second coating 121 close to the display panel 200) to form a second refracted light L3, the refraction angle of the second refracted light L3 is θ3, the second refracted light L3 is finally incident on the surface of the display panel 200, and the distance from the position where the second refracted light L3 reaches the surface of the display panel 200 to the normal N1 is d0.

[0055] Figure 3 Reference (b) is a schematic diagram of the optical path of the first coating 111, wherein the incident light L1 is incident from the first surface K3 of the first coating 111 (K3 is the surface of the first coating 111 away from the display panel 200) to the interior of the first coating 111, and the incident angle of the incident light L1 is θ1, that is, the angle between the incident light L1 and its corresponding normal N1 is θ1. The incident light L1 enters the interior of the first coating 111 and is refracted to form a first refracted light L2', and the refraction angle of the first refracted light L2' is θ2'. The first refracted light L2' is emitted from the second surface K4 of the first coating 111 (K4 is the surface of the first coating 111 close to the display panel 200) to form a second refracted light L3', and the refraction angle of the second refracted light L3' is θ3'. The second refracted light L3' is finally incident on the surface of the display panel 200, wherein the distance from the position where the second refracted light L3' reaches the surface of the display panel 200 to the normal N1 is d1.

[0056] In the present application, when the refractive index n1 and thickness D1 of the first coating 111 satisfy the relational expression III, it can be ensured that the distance d1 from the position where the incident light L1 passes through the first coating 111 and is incident on the surface of the display panel 200 to the normal line N1 is equal to the distance d0 from the position where the incident light L1 passes through the second coating 121 and is incident on the surface of the display panel 200 to the normal line N1, that is, d1=d0. Since the position where the incident light passes through the first coating 111 and is incident on the surface of the display panel 200 is the same as the position where the incident light passes through the second coating 121 and is incident on the surface of the display panel 200, it can be ensured that the optical path incident on the inside of the display panel 200 is the same as the original designed optical path, thereby ensuring that the protective film 110 can match the original optical design of the existing display module.

[0057] In the above relationship III, the refractive index n0 and thickness D0 of the second coating 121 and the incident angle θ1 of the incident light L1 are known values. When the refractive index n1 of the selected first coating 111 is determined, the thickness D1 of the first coating 111 can be calculated according to the above relationship III, or when the thickness D1 of the selected first coating 111 is determined, the refractive index n1 of the first coating 111 can be calculated according to the above relationship III. Therefore, the protective film 110 of the present application can be replaced with a variety of protective films 110 of different thicknesses and different refractive indices, and the selectivity is large. It is only necessary that the refractive index n1 and thickness D1 of the first coating 111 of the protective film 110 satisfy the relationship III to ensure that the protective film 110 can match the original optical design of the existing display module. And the protective film 110 can be directly torn off and replaced again after being scratched or damaged after a period of use, so as to better protect the screen of the display module and ensure the optical performance of the display module, thereby ensuring a relatively stable user experience.

[0058] In the present application, the refractive index n1 of the first coating 111 is in the range of 1.3≤n1≤1.8; the thickness D1 of the first coating 111 is in the range of 0μm<D1≤100μm; the refractive index n0 of the second coating 121 is in the range of 1.3≤n0≤1.8; the thickness D0 of the second coating 121 is in the range of 0μm<D0≤100μm; so as to meet the optical performance of the display module.

[0059] See also Figure 2, the existing display module usually also includes a camera 300, the display panel 200 includes a camera area CA, and the camera 300 is located on the side of the display panel 200 away from the original protective film 120, and corresponds to the camera area CA. The camera 300 realizes imaging by incident ambient light into the lens. Therefore, the replacement of the protective film of the existing display module has a greater impact on the optical performance of the camera 300. For example, when the thickness and refractive index of the second coating 121 change, the optical path of the incident light to the lens will change accordingly, resulting in optical problems such as defocus and virtual focus when the camera 300 is shooting.

[0060] In this application, please refer to Figure 1-Figure 3 , the display panel 200 includes a camera area CA, and the camera area CA is provided with an opening 201. Specifically, the opening 201 penetrates the support layer 240, the adhesive layer 260, the back layer 230 and the flexible display layer 210. The display module 10 also includes a camera 300, which is located on a side of the display panel 200 away from the protective film 110 and corresponds to the camera area CA. Specifically, the camera 300 is located on a side of the support layer 240 away from the back layer 230 and corresponds to the position of the opening 201.

[0061] The distance from the position where the incident light ray L1 passes through the protective film 110 to reach the surface of the imaging area CA to the normal line N1 corresponding to the incident light ray L1 is d1', and the distance from the position where the incident light ray L1 passes through the original protective film 120 to reach the surface of the imaging area CA to the normal line N1 corresponding to the incident light ray L1 is d0', wherein d1'=d0', which can ensure that the light path incident on the camera 300 remains unchanged, thereby ensuring that the optical performance of the camera 300 is not affected, and avoiding problems such as defocus and out-of-focus in the existing display module after replacing the protective film 110. The schematic diagram of the light path of the incident light ray L1 passing through the protective film 110 to reach the surface of the imaging area CA and the incident light ray L1 passing through the original protective film 120 to reach the surface of the imaging area CA can be referred to. Figure 3 The principle of d1'=d0' is similar to the principle of d1=d0 mentioned above, and will not be repeated here.

[0062] In some embodiments, the incident angle θ1 may be equal to the shooting angle of the camera 300, which refers to the angle of incident light when the camera 300 shoots an object. Therefore, in equations I to III, the value of the incident angle θ1 may be determined by the shooting angle parameter of the camera 300.

[0063] In some embodiments, the incident angle θ1 has a preset range, and the preset range is between 0° and 60°. The preset range has a maximum value, and the incident angle θ1 is equal to the maximum value. Specifically, the preset range can be the shooting angle range of the camera 300, that is, the angle range of the incident light that can enter the camera. The maximum value is the maximum angle that the camera 300 can shoot. When calculating the refractive index n1 and thickness D1 of the first coating 111 using relationship formulas I to III, the value of the incident angle θ1 can select the maximum shooting angle of the camera 300 to ensure that the optical performance of the camera 300 under close-range and long-range shooting conditions can meet the requirements.

[0064] In some embodiments, the range of the incident angle θ1 is 0°<θ1≤60°, and the range of θ1 is related to the optical setting of the camera 300. The incident angle θ1 can be any angle value within the range of 0°<θ1≤60°.

[0065] In some embodiments, see Figure 1 The protective film 110 further includes a first substrate layer 112, which is located on a side of the first coating layer 111 close to the display panel 200; a refractive index n2 of the first substrate layer 112 is equal to a first preset value, and a thickness D2 of the first substrate layer 112 is equal to a second preset value.

[0066] See also Figure 2 The original protective film 120 includes a second substrate layer 122, and the second substrate layer 122 is located on a side of the second coating layer 121 close to the display panel 200; the refractive index of the second substrate layer 122 is n2', and the thickness of the second substrate layer 122 is D2'.

[0067] Among them, the first preset value is equal to the refractive index of the second substrate layer 122, that is, the refractive index of the first substrate layer 112 is the same as that of the second substrate layer 122, n2=n2'; the second preset value is equal to the thickness of the second substrate layer 122, that is, the thickness of the first substrate layer 112 is the same as that of the second substrate layer 122, D2=D2', so as to ensure that the light path passing through the first substrate layer 112 is the same as the light path passing through the second substrate layer 122, thereby ensuring that the position where the incident light L1 reaches the display panel 200 through the protective film 110 is the same as the position where the incident light L1 reaches the display panel 200 through the original protective film 120, so as to ensure that the protective film 110 as a whole can match the original optical design of the display module.

[0068] In some embodiments, the material of the first substrate layer 112 and the material of the second substrate layer 122 may be the same, so that the refractive index of the first substrate layer 112 and the refractive index of the second substrate layer 122 are the same.

[0069] In some embodiments, the material of the first coating layer 111 includes at least one of an acrylate compound or an epoxy resin compound. These compounds have high hardness and good friction resistance, which are beneficial for protecting the display module from scratches or damages.

[0070] In some embodiments, other functional additives may be added to the first coating layer 111, such as additives with anti-fingerprint function, but the present invention is not limited thereto.

[0071] In some embodiments, the material of the first substrate layer 112 includes at least one of polyethylene terephthalate (PET), polypropylene (PP), polymethyl methacrylate (PMMA), polycarbonate (PC), triacetyl cellulose (TAC), transparent polyimide (CPI), and ultra-thin flexible glass (UTG) to provide basic protection for the display module.

[0072] In some embodiments, see Figure 1 The protective film 110 further includes a first adhesive layer 113, which is located on a side of the first substrate layer 112 away from the first coating layer 111 and is used to bond the first substrate layer 112 and the display panel 200. The first adhesive layer 113 of the protective film 110 has the same refractive index and thickness as the second adhesive layer 123 of the original protective film 120, wherein the second adhesive layer 123 is located between the second substrate layer 122 and the display panel 200. The material of the first adhesive layer 113 may be, but is not limited to, a pressure sensitive adhesive (PSA).

[0073] The display module of the present application is further described below through specific embodiments.

[0074] Example 1

[0075] It is known that the material of the second substrate layer 122 of the original protective film 120 is polyethylene terephthalate (PET), the refractive index n0 of the second coating layer 121 is 1.6, and the thickness D0 of the second coating layer 121 is 35 μm; the maximum shooting angle θ1 of the camera 300 of the display module is 60°;

[0076] The material of the first substrate layer 112 of the protective film 110 is polyethylene terephthalate (PET), which is the same as the second substrate layer 122 of the original protective film 120. According to the relationship III:

[0077]

[0078] It can be calculated that the refractive index n1 of the first coating layer 111 is 1.5, and the thickness D1 of the first coating layer 111 is 37 μm.

[0079] Therefore, in this embodiment, the refractive index n1 of the first coating layer 111 can be selected to be 1.5, the thickness D1 of the first coating layer 111 can be selected to be 37 μm, and the material of the first substrate layer 112 is the protective film 110 of polyethylene terephthalate (PET) to replace the original protective film 120 .

[0080] Example 2

[0081] It is known that the material of the second substrate layer 122 of the original protective film 120 is ultra-thin flexible glass (UTG), the refractive index n0 of the second coating layer 121 is 1.52, and the thickness D0 of the second coating layer 121 is 50 μm; the maximum shooting angle θ1 of the camera 300 of the display module is 45°;

[0082] The material of the first substrate layer 112 of the protective film 110 is ultra-thin flexible glass (UTG), which is the same as the second substrate layer 122 of the original protective film 120. According to the relationship III:

[0083]

[0084] It can be calculated that the refractive index n1 of the first coating layer 111 is 1.65, and the thickness D1 of the first coating layer 111 is 47 μm.

[0085] Therefore, in this embodiment, the refractive index n1 of the first coating 111 can be selected to be 1.65, the thickness D1 of the first coating 111 can be selected to be 47 μm, and the material of the first substrate layer 112 is the ultra-thin flexible glass (UTG) protective film 110 to replace the original protective film 120 .

[0086] It should be noted that, in the above embodiment, the refractive index of the first coating 111 can be changed. When the refractive index of the selected first coating 111 is different, the thickness of the corresponding first coating 111 changes accordingly. Therefore, a display module can have a plurality of protective films 110 with different refractive indices and thicknesses to choose from.

[0087] In summary, the present application provides a display module, the display module includes a protective film, the protective film is a replaceable protective film suitable for foldable products, including a first coating, the thickness D1 of the first coating decreases monotonically with respect to the refractive index n1 of the first coating, that is, D1 decreases with the increase of n1, and D1 and n1 satisfy the relationship I. When D1 and n1 of the selected protective film satisfy the relationship I, the optical path of the incident light after passing through the protective film can be made the same as the original optical path of the display module, so that the original optical design of the protective film and the display module are matched. Therefore, the display module of the present application has a variety of protective films with different refractive indices and different thicknesses for replacement, and can ensure that the replaced protective film matches the original optical design of the display module, avoiding the optical-related problems that occur after the protective film of the existing foldable products is replaced.

[0088] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0089] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0090] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0091] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A display module, characterized in that: include: Display panel; as well as A protective film is disposed on the light-emitting side of the display panel, the protective film comprises a first coating layer, and a thickness D1 of the first coating layer decreases monotonically with respect to a refractive index n1 of the first coating layer; D1 and n1 satisfy the following relationship I: Wherein, k is a constant greater than 0, and θ1 is the incident angle of the incident light incident on the surface of the first coating.

2. The display module according to claim 1, characterized in that: The k satisfies the following relation II: Wherein, n0 is the preset refractive index, and D0 is the preset thickness.

3. The display module according to claim 2, characterized in that: The incident angle θ1 has a preset range, and the preset range is between 0° and 60°.

4. The display module according to claim 3, characterized in that: The preset range has a maximum value, and the incident angle θ1 is equal to the maximum value.

5. The display module according to claim 1, characterized in that: The refractive index n1 of the first coating layer is in the range of 1.3≤n1≤1.8, and the thickness D1 of the first coating layer is in the range of 0 μm<D1≤100 μm.

6. The display module according to claim 2, characterized in that: The range of the preset refractive index n0 is 1.3≤n0≤1.8, and the range of the preset thickness D0 is 0 μm<D0≤100 μm.

7. The display module according to any one of claims 1 to 6, characterized in that: The distance d1 between the position where the incident light passes through the protective film and reaches the surface of the display panel and the normal line corresponding to the incident light is equal to the preset distance d0.

8. The display module according to any one of claims 1 to 6, characterized in that: The display module further includes a camera, the display panel includes a camera area, and the camera is located at a side of the display panel away from the protective film and corresponds to the camera area; The distance d1' between the position where the incident light passes through the protective film and reaches the surface of the imaging area and the normal line corresponding to the incident light is equal to the preset distance d0'.

9. The display module according to any one of claims 1 to 6, characterized in that: The protective film further comprises a first substrate layer, and the first substrate layer is located on a side of the first coating layer close to the display panel; The refractive index of the first substrate layer is equal to a first preset value, and the thickness of the first substrate layer is equal to a second preset value.

10. The display module according to claim 9, characterized in that: The material of the first coating layer includes at least one of an acrylate compound or an epoxy resin compound; The material of the first substrate layer includes at least one of polyethylene terephthalate, polypropylene, polymethyl methacrylate, polycarbonate, triacetyl cellulose, transparent polyimide, and ultra-thin flexible glass.

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