Cover plate and preparation method thereof, display module and display device

Abstract

The invention provides a cover plate and a preparation method thereof, a display module and a display device. The cover plate comprises a substrate; the composite film layer is positioned on one side of the substrate; wherein the composite film layer comprises a positive expansion material and a negative expansion material. According to the cover plate provided by the invention, the composite film layer containing the positive expansion material and the negative expansion material is formed on the substrate, the positive expansion material is used for improving the hardness and friction resistance of the film layer, and the negative expansion characteristic of the negative expansion material is used for counteracting the strong extrusion stress generated by the positive expansion material; therefore, the extrusion stress in the superhard coating layer is eliminated, cover plate warping caused by the extrusion stress of the positive expansion material is avoided, and the warping problem of the cover plate is effectively solved. Meanwhile, the warping problem of the cover plate does not need to be improved by reducing ICP deposition power, and high ICP deposition power can be kept, so that it is guaranteed that the hardness and friction resistance of the film layer are not affected.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a cover plate and a preparation method thereof, a display module, and a display device. Background Art

[0002] Organic Light Emitting Display (OLED) and flat-panel display devices based on technologies such as Light Emitting Diode (LED) have been widely used in various consumer electronic products such as mobile phones, televisions, laptops, desktop computers, etc. due to their advantages such as high image quality, power saving, thin body and wide application range, becoming the mainstream in display devices.

[0003] However, the performance of current OLED display products needs to be improved. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a cover plate that is conducive to eliminating the extrusion stress of the film layer and avoiding warping.

[0005] Based on the above purpose, the present application provides a cover plate, which includes:

[0006] substrate;

[0007] A composite film layer is located on one side of the substrate;

[0008] Wherein, the composite film layer includes positive expansion material and negative expansion material.

[0009] In one embodiment, the positive expansion material includes silicon nitride, and the negative expansion material includes zirconium tungstate.

[0010] In one embodiment, the positive expansion material forms a positive expansion material layer, the negative expansion material forms a negative expansion material layer, and the negative expansion material layer and the positive expansion material layer are stacked;

[0011] Preferably, the thickness ratio of the negative expansion material layer to the positive expansion material layer is 1 / 15.5 to 1 / 12.5;

[0012] Preferably, in a direction perpendicular to the thickness of the composite film layer, a gap is formed between the positive expansion materials, and the negative expansion material is at least partially located in the gap;

[0013] Preferably, the positive expansion material forms a plurality of positive expansion material layers, and the negative expansion material layer is located between two adjacent positive expansion material layers;

[0014] Preferably, the negative expansion material layer is provided in plurality, and the plurality of negative expansion material layers are respectively located between two different adjacent positive expansion material layers;

[0015] Preferably, a negative expansion material layer is arranged between every two adjacent positive expansion material layers.

[0016] In one embodiment, the hardness of the composite film layer is greater than the hardness of the substrate;

[0017] Preferably, the substrate comprises glass.

[0018] Based on the same inventive concept, the present application also discloses a method for preparing a cover plate, which comprises:

[0019] providing a substrate;

[0020] A composite film layer is formed on one side of the substrate; wherein the composite film layer includes a positive expansion material and a negative expansion material.

[0021] In one embodiment, forming a composite film layer on one side of the substrate comprises:

[0022] Free nitrogen, free silicon and free zirconium tungstate are obtained by magnetron sputtering nitrogen, silicon oxide target and zirconium tungstate target, and a composite film layer including silicon nitride and zirconium tungstate is formed by inducing deposition on one side of the substrate;

[0023] Preferably, in the magnetron sputtering, the target excitation power ratio of the zirconium tungstate target and the silicon oxide target is 1 / 15.5 to 1 / 12.5;

[0024] Preferably, in the magnetron sputtering, the target excitation power of the silicon oxide target material is 0.75-0.85 KW, and the target excitation power of the zirconium tungstate target material is 0.01-0.11 KW.

[0025] In one embodiment, forming a composite film layer on one side of the substrate comprises:

[0026] forming a stacked positive expansion material layer and a negative expansion material layer on one side of the substrate, wherein the stacked positive expansion material layer and the negative expansion material layer form the composite film layer;

[0027] Preferably, during the preparation process, the negative expansion material is at least partially formed in the gap between the positive expansion materials.

[0028] Preferably, the preparation method further comprises:

[0029] A plurality of stacked positive expansion material layers and a plurality of stacked negative expansion material layers are formed on one side of the substrate, and one negative expansion material layer is formed between every two adjacent positive expansion material layers.

[0030] Based on the same inventive concept, the present application also discloses a display module, which includes a screen body and a cover plate as described in any one of the above items, wherein the cover plate is arranged on the display side of the screen body.

[0031] Based on the same inventive concept, the present application also discloses a display device, which includes the display module described above.

[0032] Compared with the prior art, the cover plate provided by the present application forms a composite film layer comprising a positive expansion material and a negative expansion material on a substrate, wherein the positive expansion material is used to improve the hardness and anti-friction performance of the film layer, and the negative expansion characteristics of the negative expansion material are used to offset the strong extrusion stress generated by the positive expansion material, thereby eliminating the extrusion stress in the composite film layer, avoiding the warping of the cover plate caused by the extrusion stress of the positive expansion material, and effectively improving the warping problem of the cover plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 is a schematic diagram of a related cover plate;

[0035] Figure 2 A schematic diagram of a related cover plate causing warping;

[0036] Figure 3 This is a schematic diagram of a cover plate in one embodiment of the present application;

[0037] Figure 4 This is a schematic diagram of the membrane structure of the composite membrane layer in the cover plate in one embodiment of the present application;

[0038] Figure 5 This is a schematic diagram of preparing a cover plate in one embodiment of the present application;

[0039] Figure 6 This is a flow chart of a method for preparing a cover plate in another embodiment of the present application;

[0040] Figure 7 It is a schematic diagram of a display module in another embodiment of the present application.

[0041] Marking Description:

[0042] 100, cover plate; 1, substrate; 2, first film layer; 3, composite film layer; 31, positive expansion material; 32, negative expansion material; 33, positive expansion material layer; 34, negative expansion material layer; 35, gap; 4, silicon oxide target; 5, zirconium tungstate target; 6, container; 7, pipeline; 200, display module; 210, screen body. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0044] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0045] The cover plate is an important part of the display module. It is set on the display side of the display screen to protect the display screen from external physical damage, such as scratches and collisions, to ensure the safety and stable operation of the display module. Secondly, it has good optical properties, which can ensure that the display image is presented to the user clearly and transparently, and reduce adverse effects such as light reflection and scattering. Furthermore, the cover plate can also play a certain role in dust and water resistance, maintaining the cleanliness and normal operating environment inside the display module. In addition, it plays a decorative role in appearance, making the entire display device more beautiful and textured. In short, the cover plate is of indispensable importance to the normal use, performance and appearance quality of the display module.

[0046] Please refer to Figure 1 As shown, a related cover plate 100 includes a substrate 1 and a first film layer 2, wherein the first film layer 2 is a film layer with high hardness and high anti-friction performance produced on the surface of the substrate 1 by magnetron sputtering.

[0047] In actual production, in order to improve the hardness and anti-friction performance of the first film layer 2, it is usually chosen to increase the ICP (Inductively Coupled Plasma) deposition power to improve the density of the first film layer 2. However, the high density of the first film layer 2 will produce a strong extrusion stress, causing the cover plate 100 to be squeezed toward the non-coated surface, thereby causing the cover plate 100 to warp abnormally, refer to Figure 2 shown.

[0048] After long-term research, the inventors found that the current method for improving the warpage of the cover plate 100 is usually to reduce the ICP deposition power to reduce the film layer excitation precipitation speed, thereby reducing the density of the film layer and achieving the effect of reducing the extrusion stress. However, after reducing the ICP deposition power, the hardness and wear resistance of the first film layer 2 are reduced.

[0049] Based on this, the present application provides a cover plate solution to solve the above problems.

[0050] Please refer to Figure 3 and 4 As shown, a cover plate 100 provided in an embodiment of the present application includes a substrate 1 and a composite film layer 3 , wherein the composite film layer 3 is located on one side of the substrate 1 ; wherein the composite film layer 3 includes a positive expansion material 31 and a negative expansion material 32 .

[0051] The cover plate 100 provided in the present application forms a composite film layer 3 including a positive expansion material 31 and a negative expansion material 32 on a substrate 1, wherein the positive expansion material 31 is used to improve the hardness and anti-friction performance of the film layer, and the negative expansion characteristics of the negative expansion material 32 are used to offset the strong extrusion stress generated by the positive expansion material 31, thereby eliminating the extrusion stress in the composite film layer 3, avoiding the warping of the cover plate 100 caused by the extrusion stress of the positive expansion material 31, and effectively improving the warping problem of the cover plate 100.

[0052] For details, please continue to refer to Figure 4 As shown, the negative expansion material 32 is located in the gap between the positive expansion materials 31 . When the positive expansion material 31 expands positively, the negative expansion material 32 can expand negatively (ie, shrink) to offset the strong extrusion stress generated by the positive expansion material 31 .

[0053] At the same time, the cover plate 100 provided in the present application does not need to improve the warping problem of the cover plate 100 by reducing the ICP deposition power, and can maintain a relatively high ICP deposition power to ensure that the hardness and anti-friction performance of the film layer are not affected. The addition of the negative expansion material 32 can offset the strong extrusion stress generated by the positive expansion material 31, thereby avoiding the warping of the cover plate 100 caused by the extrusion stress.

[0054] In one embodiment, the positive expansion material 31 includes silicon nitride (SiN), and the negative expansion material 32 includes zirconium tungstate (ZrW2O8). Silicon nitride has high hardness and excellent chemical stability, which can improve the film hardness and anti-friction performance of the composite film layer 3. Zirconium tungstate has the characteristic of high negative expansion. Adding zirconium tungstate to silicon nitride can offset the strong extrusion stress generated by the positive expansion material and avoid the warping of the cover plate 100 caused by the extrusion stress. In other embodiments, the positive expansion material 31 can select other materials with positive expansion characteristics and high hardness, and the negative expansion material 32 can select other materials with negative expansion characteristics, without specific limitation.

[0055] Please continue to refer to Figure 4 As shown, in one embodiment, the positive expansion material 31 forms a positive expansion material layer 33, and the negative expansion material 32 forms a negative expansion material layer 34. The negative expansion material layer 34 and the positive expansion material layer 33 are stacked, which is beneficial to offset the extrusion stress in the thickness direction of the composite film layer 3 (such as the X direction in the figure).

[0056] Preferably, the thickness ratio of the negative expansion material layer 34 to the positive expansion material layer 33 is 1 / 15.5 to 1 / 12.5; within this ratio range, the stress in the film layer can be eliminated without reducing the compactness of the film layer. Specifically, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 15.5, 1 / 14.5, 1 / 13 or 1 / 12.5, etc., which is not specifically limited.

[0057] Please continue to refer to Figure 4 As shown, in one of the embodiments, in the thickness direction perpendicular to the composite film layer 3 (such as the Y direction in the figure), a gap 35 is formed between the positive expansion materials 31, and the negative expansion material 32 is at least partially located in the gap 35, which is beneficial to offset the extrusion stress of the composite film layer 3 perpendicular to the thickness direction, thereby achieving the offset of the extrusion stress in the thickness direction and perpendicular to the thickness direction.

[0058] Please continue to refer to Figure 4 As shown, in one embodiment, the positive expansion material 31 forms a plurality of positive expansion material layers 33 , and the negative expansion material layer 34 is located between two adjacent positive expansion material layers 33 , thereby ensuring the hardness of the composite film layer 3 and offsetting the extrusion stress.

[0059] Preferably, a plurality of negative expansion material layers 34 are provided, and the plurality of negative expansion material layers 34 are respectively located between two different adjacent positive expansion material layers 33 to enhance the stress offset effect.

[0060] Preferably, a negative expansion material layer 34 is disposed between every two adjacent positive expansion material layers 33 to further enhance the stress offset effect.

[0061] In one embodiment, the hardness of the composite film layer 3 is greater than that of the substrate 1, which can effectively protect the substrate 1 and improve the anti-scratch and anti-collision performance of the cover plate 100. Preferably, the substrate 1 includes glass. As a substrate, glass has good transparency and optical properties, which can ensure a clear visual display effect; at the same time, it has high hardness and strength, which can better resist scratches and collisions in daily use; secondly, the flatness of the glass is high, which can ensure the quality of the display screen; in addition, the glass also has good chemical stability and high temperature resistance.

[0062] In one embodiment, the composite film layer 3 is obtained by magnetron sputtering nitrogen (N2), a silicon oxide target 4 and a zirconium tungstate target 5 to obtain free nitrogen, free silicon and free zirconium tungstate, and inducing deposition.

[0063] Specifically, refer to Figure 5 As shown, a substrate 1, a silicon oxide target 4 and a zirconium tungstate target 5 are placed in a container 6, nitrogen is introduced into the container 6 through a pipe 7, and magnetron sputtering is performed on the nitrogen, silicon oxide target 4 and zirconium tungstate target 5 in the container 6 to obtain free nitrogen, free silicon and free zirconium tungstate, and then, deposition of the free nitrogen, free silicon and free zirconium tungstate is induced, and under the action of the target ICP deposition power, silicon nitride and zirconium tungstate form a composite film layer 3 on the surface of the substrate 1.

[0064] Preferably, in magnetron sputtering, the target excitation power ratio of the zirconium tungstate target material and the silicon oxide target material is 1 / 15.5 to 1 / 12.5. The target excitation power ratio determines the composition ratio of the materials in the composite film layer 3. When the target excitation power ratio of the zirconium tungstate target material 5 and the silicon oxide target material 4 is 1 / 15.5 to 1 / 12.5, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 15.5 to 1 / 12.5. For example, when the target excitation power ratio of the zirconium tungstate target 5 and the silicon oxide target 4 is 1 / 15.5, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 15.5; when the target excitation power ratio of the zirconium tungstate target 5 and the silicon oxide target 4 is 1 / 13, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 13; when the target excitation power ratio of the zirconium tungstate target 5 and the silicon oxide target 4 is 1 / 12.5, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 12.5.

[0065] Preferably, in magnetron sputtering, the target excitation power of the silicon oxide target 4 is 0.75-0.85KW, such as 0.75KW, 0.78KW, 0.8KW, 0.82KW, 0.85KW, etc. The target excitation power of the zirconium tungstate target 5 is 0.01-0.11KW, such as 0.01KW, 0.03KW, 0.06KW, 0.1KW, 0.11KW, etc.

[0066] Reference Figure 6 As shown, based on the same inventive concept, another embodiment of the present application further discloses a method for preparing a cover plate, and the cover plate 100 prepared by the preparation method is as follows Figure 3 As shown, the preparation method comprises the following steps:

[0067] Step S10, providing a substrate 1; preferably, the substrate 1 includes glass. Glass as a substrate has good transparency and optical properties, and can ensure a clear visual display effect; at the same time, it has high hardness and strength, and can better resist scratches and collisions in daily use; secondly, the flatness of the glass is high, which can ensure the quality of the display image; in addition, the glass also has good chemical stability and high temperature resistance.

[0068] Step S20, forming a composite film layer 3 on one side of the substrate 1; wherein the composite film layer 3 includes a positive expansion material 31 and a negative expansion material 32, referring to Figure 4 shown.

[0069] The preparation method of the cover plate provided in the present application is achieved by arranging a composite film layer 3 comprising a positive expansion material 31 and a negative expansion material 32 on a substrate 1, wherein the positive expansion material 31 is used to improve the hardness and anti-friction performance of the film layer, and the negative expansion characteristics of the negative expansion material 32 are used to offset the strong extrusion stress generated by the positive expansion material, thereby eliminating the extrusion stress in the composite film layer 3, avoiding the warping of the cover plate 100 caused by the extrusion stress of the positive expansion material 31, and effectively improving the warping problem of the cover plate 100.

[0070] For details, please continue to refer to Figure 4 As shown, the negative expansion material 32 is located in the gap between the positive expansion materials 31 . When the positive expansion material 31 expands positively, the negative expansion material 32 can expand negatively (ie, shrink) to offset the strong extrusion stress generated by the positive expansion material 31 .

[0071] At the same time, the cover plate 100 provided in the present application does not need to improve the warping problem of the cover plate 100 by reducing the ICP deposition power, and can maintain a relatively high ICP deposition power to ensure that the hardness and anti-friction performance of the film layer are not affected. The addition of the negative expansion material 32 can offset the strong extrusion stress generated by the positive expansion material 31, thereby avoiding the warping of the cover plate 100 caused by the extrusion stress.

[0072] In one embodiment, the positive expansion material 31 includes silicon nitride (SiN), and the negative expansion material 32 includes zirconium tungstate (ZrW2O8). Silicon nitride has high hardness and excellent chemical stability, which can improve the film hardness and anti-friction performance of the composite film layer 3. Zirconium tungstate has the characteristic of high negative expansion. Adding zirconium tungstate to silicon nitride can offset the strong extrusion stress generated by the positive expansion material and avoid the warping of the cover plate 100 caused by the extrusion stress. In other embodiments, the positive expansion material 31 can select other materials with positive expansion characteristics and high hardness, and the negative expansion material 32 can select other materials with negative expansion characteristics, without specific limitation.

[0073] In one embodiment, step S20, forming a composite film layer 3 on one side of the substrate 1, comprises the following steps:

[0074] A stacked positive expansion material layer 33 and a negative expansion material layer 34 are formed on one side of the substrate 1, and the stacked positive expansion material layer 33 and the negative expansion material layer 34 form a composite film layer 3. Figure 4 As shown, the negative expansion material layer 34 and the positive expansion material layer 33 are stacked, which is beneficial to offset the extrusion stress in the thickness direction (such as the X direction in the figure) of the composite film layer 3 .

[0075] Preferably, during the preparation process, the negative expansion material 32 is at least partially formed in the gap between the positive expansion materials 31. Figure 4 As shown, in the thickness direction perpendicular to the composite film layer 3 (such as the Y direction in the figure), a gap 35 is formed between the positive expansion materials 31, and the negative expansion material 32 is at least partially located in the gap 35, which is beneficial to offset the extrusion stress of the composite film layer 3 perpendicular to the thickness direction, thereby achieving the offset of the extrusion stress in the thickness direction and perpendicular to the thickness direction.

[0076] Furthermore, the preparation method further comprises the following steps:

[0077] Multiple positive expansion material layers 33 and multiple negative expansion material layers 34 are stacked on one side of the substrate 1 , and a negative expansion material layer 34 is formed between every two adjacent positive expansion material layers 33 , thereby ensuring the hardness of the composite film layer 3 and offsetting the extrusion stress.

[0078] Preferably, the thickness ratio of the negative expansion material layer 34 to the positive expansion material layer 33 is 1 / 15.5 to 1 / 12.5; within this ratio range, it is possible to ensure that the stress in the film layer is eliminated while not reducing the density of the film layer. Specifically, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 15.5, 1 / 14.5, 1 / 13 or 1 / 12.5, etc., which is not specifically limited. In one embodiment, in step S20, a composite film layer 3 is formed on one side of the substrate 1, including:

[0079] Free nitrogen, free silicon and free zirconium tungstate are obtained by magnetron sputtering nitrogen, silicon oxide target and zirconium tungstate target, and deposition is induced on one side of the substrate 1 to form a composite film layer 3 including silicon nitride and zirconium tungstate.

[0080] Specifically, refer to Figure 5 As shown, step S20 includes: placing a substrate 1, a silicon oxide target 4 and a zirconium tungstate target 5 in a container 6, introducing nitrogen into the container 6 through a pipe 7, and magnetron sputtering the nitrogen, the silicon oxide target 4 and the zirconium tungstate target 5 in the container 6 to obtain free nitrogen, free silicon and free zirconium tungstate, and then inducing deposition of the free nitrogen, free silicon and free zirconium tungstate, and under the action of the target ICP deposition power, silicon nitride and zirconium tungstate form a composite film layer 3 on the surface of the substrate 1.

[0081] Preferably, in magnetron sputtering, the target excitation power ratio of the zirconium tungstate target material and the silicon oxide target material is 1 / 15.5 to 1 / 12.5. The target excitation power ratio determines the composition ratio of the materials in the composite film layer 3. When the target excitation power ratio of the zirconium tungstate target material 5 and the silicon oxide target material 4 is 1 / 15.5 to 1 / 12.5, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 15.5 to 1 / 12.5. For example, when the target excitation power ratio of the zirconium tungstate target 5 and the silicon oxide target 4 is 1 / 15.5, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 15.5; when the target excitation power ratio of the zirconium tungstate target 5 and the silicon oxide target 4 is 1 / 13, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 13; when the target excitation power ratio of the zirconium tungstate target 5 and the silicon oxide target 4 is 1 / 12.5, the composition ratio of zirconium tungstate and silicon nitride in the composite film layer 3 is 1 / 12.5.

[0082] Preferably, in magnetron sputtering, the target excitation power of the silicon oxide target 4 is 0.75-0.85KW, such as 0.75KW, 0.78KW, 0.8KW, 0.82KW, 0.85KW, etc. The target excitation power of the zirconium tungstate target 5 is 0.01-0.11KW, such as 0.01KW, 0.03KW, 0.06KW, 0.1KW, 0.11KW, etc. .

[0083] Based on the same inventive concept, another embodiment of the present application further discloses a display module 200. Figure 7 As shown, it includes a screen body 210 and the cover plate 100 in the above embodiment. The cover plate 100 is located on the display side of the screen body 210 and is used to protect the screen body 210.

[0084] The present embodiment provides a display module 200, wherein the cover plate 100 forms a composite film layer 3 including a positive expansion material 31 and a negative expansion material 32 on a substrate 1, wherein the positive expansion material 31 is used to improve the hardness and anti-friction performance of the film layer, and the negative expansion characteristics of the negative expansion material 32 are used to offset the strong extrusion stress generated by the positive expansion material 31, thereby eliminating the extrusion stress in the composite film layer 3, avoiding the warping of the cover plate 100 caused by the extrusion stress of the positive expansion material 31, and effectively improving the warping problem of the cover plate 100. At the same time, there is no need to improve the warping problem of the cover plate 100 by reducing the ICP deposition power, and a high ICP deposition power can be maintained to ensure that the hardness and anti-friction performance of the film layer are not affected, thereby improving the performance of the display module 200.

[0085] Based on the same inventive concept, another embodiment of the present application further discloses a display device, which includes the display module 200 in the above embodiment. Further, the display device includes a mobile phone, a VR device, a computer, a television, a car display device, etc.

[0086] The present embodiment provides a display device, wherein the display module 200 includes a cover plate 100, wherein the cover plate 100 forms a composite film layer 3 including a positive expansion material 31 and a negative expansion material 32 on a substrate 1, wherein the positive expansion material 31 is used to improve the hardness and anti-friction performance of the film layer, and the negative expansion characteristics of the negative expansion material 32 are used to offset the strong extrusion stress generated by the positive expansion material 31, thereby eliminating the extrusion stress in the composite film layer 3, avoiding the warping of the cover plate 100 caused by the extrusion stress of the positive expansion material 31, and effectively improving the warping problem of the cover plate 100. At the same time, there is no need to improve the warping problem of the cover plate by reducing the ICP deposition power, and a high ICP deposition power can be maintained to ensure that the hardness and anti-friction performance of the film layer are not affected, thereby improving the performance of the display device.

[0087] Although the present application has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0088] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0089] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A cover plate, characterized in that: include: substrate; A composite film layer is located on one side of the substrate; Wherein, the composite film layer includes positive expansion material and negative expansion material.

2. The cover plate according to claim 1, characterized in that: The positive expansion material includes silicon nitride, and the negative expansion material includes zirconium tungstate.

3. The cover plate according to claim 1, characterized in that: The positive expansion material forms a positive expansion material layer, the negative expansion material forms a negative expansion material layer, and the negative expansion material layer and the positive expansion material layer are stacked; Preferably, the thickness ratio of the negative expansion material layer to the positive expansion material layer is 1 / 15.5 to 1 / 12.5; Preferably, in a direction perpendicular to the thickness of the composite film layer, a gap is formed between the positive expansion materials, and the negative expansion material is at least partially located in the gap; Preferably, the positive expansion material forms a plurality of positive expansion material layers, and the negative expansion material layer is located between two adjacent positive expansion material layers; Preferably, the negative expansion material layer is provided in plurality, and the plurality of negative expansion material layers are respectively located between two different adjacent positive expansion material layers; Preferably, a negative expansion material layer is arranged between every two adjacent positive expansion material layers.

4. The cover plate according to claim 1, characterized in that: The hardness of the composite film layer is greater than the hardness of the substrate; Preferably, the substrate comprises glass.

5. A method for preparing a cover plate, characterized in that: include: providing a substrate; A composite film layer is formed on one side of the substrate; wherein the composite film layer includes a positive expansion material and a negative expansion material.

6. The method for preparing the cover plate according to claim 5, characterized in that: The forming of a composite film layer on one side of the substrate comprises: Free nitrogen, free silicon and free zirconium tungstate are obtained by magnetron sputtering nitrogen, silicon oxide target and zirconium tungstate target, and a composite film layer including silicon nitride and zirconium tungstate is formed by inducing deposition on one side of the substrate; preferably, in the magnetron sputtering, the target excitation power ratio of the zirconium tungstate target and the silicon oxide target is 1 / 15.5 to 1 / 12.5; Preferably, in the magnetron sputtering, the target excitation power of the silicon oxide target material is 0.75-0.85 KW, and the target excitation power of the zirconium tungstate target material is 0.01-0.11 KW.

7. The method for preparing the cover plate according to claim 5, characterized in that: The method of forming a composite film layer on one side of the substrate comprises: forming a stacked positive expansion material layer and a negative expansion material layer on one side of the substrate, wherein the stacked positive expansion material layer and the negative expansion material layer form the composite film layer; Preferably, during the preparation process, the negative expansion material is at least partially formed in the gap between the positive expansion materials.

8. The method for preparing the cover plate according to claim 7, characterized in that: The preparation method further comprises: A plurality of stacked positive expansion material layers and a plurality of stacked negative expansion material layers are formed on one side of the substrate, and one negative expansion material layer is formed between every two adjacent positive expansion material layers.

9. A display module, characterized in that: include: A screen body, and a cover plate as described in any one of claims 1 to 4, wherein the cover plate is arranged on the display side of the screen body.

10. A display device, characterized in that: Comprising the display module as claimed in claim 9.

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