CN113419372A

CN113419372A - Black matrix for liquid crystal panel, preparation method of black matrix, substrate and liquid crystal panel

Info

Publication number: CN113419372A
Application number: CN202110634518.0A
Authority: CN
Inventors: 周世新
Original assignee: TCL China Star Optoelectronics Technology Co Ltd
Current assignee: TCL China Star Optoelectronics Technology Co Ltd
Priority date: 2021-06-08
Filing date: 2021-06-08
Publication date: 2021-09-21
Anticipated expiration: 2041-06-08
Also published as: CN113419372B

Abstract

The application discloses a black matrix for a liquid crystal panel, a preparation method of the black matrix, a substrate and the liquid crystal panel, which can be applied to a curved screen. The black matrix for the liquid crystal panel comprises a silica nanoparticle pattern layer and a Polydimethylsiloxane (PDMS) film layer, wherein the PDMS film layer covers the silica nanoparticle pattern layer. According to the curved-surface screen COA type liquid crystal display panel, the rigid silicon dioxide nanoparticles and the flexible black matrix of polydimethylsiloxane are adopted to replace the existing black matrix material to be applied to the curved-surface screen, the black matrix can effectively solve the problem that the common black matrix is shaded due to limitation of the UV irradiation direction of HVA (high voltage alternating current) processing procedure in the existing curved-surface screen COA type liquid crystal panel, the liquid crystal alignment effect is enhanced, and the electrical performance and the panel reliability of the panel are improved.

Description

Black matrix for liquid crystal panel, preparation method of black matrix, substrate and liquid crystal panel

Technical Field

The application relates to the technical field of display, in particular to a black matrix for a liquid crystal panel, a preparation method of the black matrix, a substrate and the liquid crystal panel.

Background

Polymer stabilized vertical alignment (PS-VA) is a technique for TFT-LCD. In the cell-forming process of PS-VA, as shown in fig. 1, a Polyimide (PI) alignment film 22 is required to be coated on the CF substrate (and/or TFT substrate) 20 to control the alignment direction of the liquid crystal molecules 24. However, the PI material has poor heat resistance and aging resistance, and the ability of anchoring LC molecules is not strong enough to affect the quality of the liquid crystal panel to a certain extent; the PI material has high polarity and high water absorption, and is easy to deteriorate in storage and transportation to cause poor alignment; the process cost of forming the film on the TFT-LCD by the PI material is higher, so that the cost of the panel is higher; the commercial PI material contains over 95 percent of organic solvents such as NMP, NEP, BC and the like, and a large amount of organic solvents are used and volatilized, so that the environmental pollution is easily caused. As the generation line of the panel becomes higher, on the one hand, the cost of each processing equipment is gradually increased; on the other hand, the panel price is gradually lowered, so the cost control of each production link is severe.

At present, a technique for controlling the alignment of liquid crystal molecules 24 using an Additive material 22"(Additive material) that can be added to a liquid crystal material to produce a self-alignment effect has been developed (PI-less technique), as shown in fig. 2; the additive material 22 "may be, for example, as shown in FIG. 3, having a polar portion and a non-polar portion including polymerizable groups. The PI-less technology can save the related process, equipment and maintenance of a PI section in a production link, can reduce the production cost, and the application of the technology can greatly reduce the use and volatilization of organic solvents such as N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), Butyl Carbonate (BC) and the like, and reduce the harm to the environment and personnel.

In the PI-less technology, the diffusivity of the Additive Material (Additive Material) tends to determine the quality of the alignment in the AA (active area) area of the panel. If the Additive Material (Additive Material) has poor film-forming uniformity, it causes problems such as poor alignment, poor panel electrical properties, poor reliability (IS-Image tack performance), and the like. However, in a COA type (COA) liquid crystal display panel, as shown in fig. 4, the panel includes a CF substrate 110 and a TFT substrate 120, wherein a Black Matrix (BM) 100 "is disposed on the CF substrate 110, and the irradiation direction of UV light is limited by an HVA process (High Vertical Alignment), so that the black matrix 100" blocks part of UV light, which causes non-uniformity of polymer (polymer) formed by an additive material and a liquid crystal active material RM in a liquid crystal material, thereby causing incomplete film formation or poor film formation uniformity of the additive film 130 (as shown by a dotted line in fig. 4).

Therefore, it is desired to provide a black matrix for a liquid crystal panel, which can enhance the uniformity of the film formation of the additive in the PI-less liquid crystal, and further improve the performance of the liquid crystal panel.

Disclosure of Invention

The application provides a black matrix for liquid crystal display panel, adopts the black matrix of rigid silica nanoparticle and flexible polydimethylsiloxane to replace existing black matrix material and use on the curved screen, can strengthen the liquid crystal and join in marriage the direction the effect, and then improves the electrical property and the panel reliability of panel.

The application provides a black matrix for a liquid crystal panel, the black matrix comprises a silicon dioxide nanoparticle pattern layer and a Polydimethylsiloxane (PDMS) film layer, and the PDMS film layer covers the silicon dioxide nanoparticle pattern layer.

Optionally, in some embodiments of the present application, the refractive index of the silica nanoparticle pattern layer is 1.46 ± 0.02.

Optionally, in some embodiments of the present application, the polydimethylsiloxane has a refractive index of 1.43 ± 0.02.

Optionally, in some embodiments of the present application, the diameter of the silica nanoparticle pattern layer is 500 ± 50 nm.

The black matrix is transparent in a planar state; and the black matrix becomes opaque under a compressive load.

Correspondingly, this application still provides a curved surface screen base plate for liquid crystal display panel, including substrate base plate and the black matrix that sets up in substrate base plate surface, the black matrix is foretell black matrix. The black matrix comprises a silicon dioxide nanoparticle pattern layer and a polydimethylsiloxane membrane layer.

In addition, this application still provides a liquid crystal display panel, liquid crystal display panel includes relative and parallel arrangement's first base plate and second base plate, first base plate orientation one side of second base plate is provided with the black matrix, the black matrix includes silica nanoparticle pattern layer and polydimethylsiloxane rete, just polydimethylsiloxane rete covers silica nanoparticle pattern layer.

Optionally, in some embodiments of the present application, the liquid crystal panel is a COA type liquid crystal panel, and a color photoresist layer, a planarization layer, and a pixel electrode layer are sequentially disposed on one side of the second substrate facing the first substrate.

Optionally, in some embodiments of the present application, the black matrix is transparent when the liquid crystal panel is in a planar state. And the black matrix becomes opaque when the liquid crystal panel is under a compressive load.

In addition, the application also provides a preparation method of the black matrix for the liquid crystal panel, which comprises the following steps:

providing a substrate base plate;

carrying out patterned inkjet printing on a black matrix area on the surface of the substrate by using a silicon dioxide nanoparticle solution to form a rigid silicon dioxide nanoparticle pattern layer;

forming a film in the black matrix area by adopting polydimethylsiloxane slurry, namely forming a flexible polydimethylsiloxane film layer on the rigid silicon dioxide nanoparticle pattern layer;

and the silicon dioxide nano particle pattern layer and the polydimethylsiloxane film layer form a black matrix.

Optionally, in some embodiments of the present application, the preparation of the silica nanoparticle solution comprises the following steps:

centrifuging the monodisperse silicon dioxide nanometer solution (with the mass concentration of 20%) with the diameter of 500 +/-50 nanometers, removing transparent liquid, and collecting precipitates;

and mixing the precipitate with formamide to obtain a silica nanoparticle suspension with the mass concentration of 20 +/-2%, and performing ultrasonic treatment to ensure complete dispersion to obtain a rigid silica nanoparticle solution for spraying.

Alternatively, in some embodiments of the present application, the preparation of the polydimethylsiloxane slurry comprises the steps of:

according to the weight ratio of 8-12: 1 weight ratio of the base agent to the polydimethylsiloxane curing agent to obtain slurry, and removing bubbles by vacuum defoaming to obtain the polydimethylsiloxane slurry.

Optionally, in some embodiments of the present application, a method for preparing a black matrix for a liquid crystal panel includes the following steps:

providing a substrate base plate;

carrying out patterned inkjet printing on a black matrix region on the surface of the substrate by using a silica nanoparticle solution as a spraying liquid, and drying at 90 +/-3 ℃ for 30 +/-2 minutes to completely volatilize formamide to form a silica nanoparticle pattern layer;

forming a film on the silicon dioxide nano particle pattern layer by adopting polydimethylsiloxane slurry, baking for 12 +/-0.5 hours at the temperature of 75 +/-2 ℃ for curing, cooling for 30 +/-5 minutes, and forming a polydimethylsiloxane film layer after curing;

the silicon dioxide nano particle pattern layer and the polydimethylsiloxane film layer form a black matrix.

The beneficial effect of this application lies in:

the black matrix comprises a silicon dioxide nano-particle pattern layer and a polydimethylsiloxane film layer

The composite material of rigid silicon dioxide nano particles and flexible Polydimethylsiloxane (PDMS) is adopted to replace the existing common black matrix material and is applied to a curved screen machine, so that the alignment effect of liquid crystal can be enhanced, and the electrical property and the panel reliability of the panel are improved. The black matrix effectively solves the problem of shading of a common Black Matrix (BM) caused by limitation of UV irradiation directions of HVA processing in a curved-surface screen COA model.

In the black matrix of the present application, since the optical characteristics of polydimethylsiloxane and silica nanomaterial are similar, the black matrix composite is completely transparent in a normal state (planar state). However, since the mechanical strength between the polydimethylsiloxane and the silica is very different, under a compressive load, a buckling type instability occurs on the surface of the silica nanoparticle pattern layer, which results in the generation of 1D or 2D wrinkles in the form of a grating, i.e., the black matrix of the present application becomes opaque.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of a partial structure of a prior art LCD panel;

FIG. 2 is a schematic diagram of a part of a prior art LCD panel using PI-less technology;

FIG. 3 is a schematic illustration of the additive material of FIG. 2;

FIG. 4 is a schematic diagram of a second partial structure of a prior art liquid crystal display panel using PI-less technology;

FIG. 5 is a schematic structural diagram of a patterned layer of silica nanoparticles provided in an embodiment of the present application;

FIG. 6 is a schematic structural diagram of a silica nanoparticle pattern layer and a polydimethylsiloxane membrane layer provided in an example of the present application;

fig. 7 is a schematic structural diagram of a liquid crystal display panel provided in an embodiment of the present application.

The reference numbers in the drawings are respectively:

100. a black matrix; 101. a silica nanoparticle pattern layer; 102. a polydimethylsiloxane film layer; 10. a substrate base plate; 200. a liquid crystal panel; 210. a first substrate; 220. a second substrate; 230. a color photoresist layer; 240. a planarization layer; 250. a pixel electrode layer; 260. a membrane structure.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The embodiment of the application provides a black matrix for a liquid crystal panel, a preparation method of the black matrix, a substrate and the liquid crystal panel. The following are detailed below. It should be noted that the following description of the embodiments is not intended to limit the preferred order of the embodiments.

In addition, in the description of the present application, the term "including" means "including but not limited to". The terms first, second, third and the like are used merely as labels, and do not impose numerical requirements or an established order. Various embodiments of the invention may exist in a range of versions; it is to be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention; accordingly, the described range descriptions should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, it is contemplated that the description of a range from 1 to 6 has specifically disclosed sub-ranges such as, for example, from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within a range such as, for example, 1, 2, 3, 4, 5, and 6, as applicable regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any number (fractional or integer) recited within the indicated range.

Referring to fig. 5 and 6, a black matrix 100 for a liquid crystal panel includes a silica nanoparticle pattern layer 101 and a Polydimethylsiloxane (PDMS) film layer 102. The polydimethylsiloxane film layer 102 covers the silica nanoparticle pattern layer 101.

In this embodiment, the material of the black matrix 100 includes a rigid silica nanoparticle structure and flexible polydimethylsiloxane.

In some embodiments, the silica nanoparticle pattern layer 101 is formed using silica having a refractive index of 1.46 ± 0.02; for example, the refractive index of the silicon dioxide may be 1.475. The diameter of the silica may be 500 ± 50 nm; for example, the silica has a diameter of 500 nm.

In some embodiments, the polydimethylsiloxane has a refractive index of 1.43 ± 0.02; for example, the refractive index of the polydimethylsiloxane used for the polydimethylsiloxane film layer 102 may be 1.43.

The present application further provides a curved-panel liquid crystal panel substrate, please refer to fig. 5 and fig. 6, which includes a substrate 10 and a black matrix 100 disposed on the surface of the substrate 10. The black matrix is the black matrix, specifically, the black matrix 100 includes a silica nanoparticle pattern layer 101 and a polydimethylsiloxane film layer 102, and the polydimethylsiloxane film layer 102 covers the silica nanoparticle pattern layer 101. For example, the substrate may be a COA type substrate.

In this embodiment, the black matrix in the substrate uses the rigid silica nanoparticle pattern layer and the flexible polydimethylsiloxane film layer to replace the existing black matrix material, and is applied to the curved screen, so that the phenomenon of shading of the common black matrix caused by limitation of the UV irradiation direction in the HVA process in the COA model of the curved screen can be solved.

Correspondingly, the embodiment of the application also provides a liquid crystal panel, wherein the liquid crystal panel is a COA type liquid crystal panel and is applied to a curved screen. Referring to fig. 7, the liquid crystal panel 200 includes a first substrate 210, a second substrate 220, a color photoresist layer 230, a planarization layer 240, a pixel electrode layer 250, and a black matrix 100. Specifically, the liquid crystal panel 200 includes a first substrate 210 and a second substrate 220 disposed in parallel and opposite to each other, and the black matrix 100 is disposed on a side of the first substrate 210 facing the second substrate 220. The black matrix 100 includes a rigid silica nanoparticle pattern layer 101 and a flexible polydimethylsiloxane membrane layer 102, and the polydimethylsiloxane membrane layer covers the silica nanoparticle pattern layer. The second substrate is provided with a color photoresist layer 230, a flat layer 240 and a pixel electrode layer 250 in sequence on one side facing the first substrate.

In the present embodiment, the black matrix 100 of the liquid crystal panel 200 is transparent in a planar state, and does not block the UV light in the HVA process, so that the liquid crystal material and the additive material are polymerized to form the uniform film structure 260. Compared with the prior art (see fig. 4), in the curved panel type, the application replaces the existing common BM material with the rigid silica nanoparticle structure and the flexible Polydimethylsiloxane (PDMS), and solves the problem of uneven film formation caused by shading of a common black matrix due to limitation of the UV irradiation direction in the HVA process in the curved panel COA type.

Specifically, the black matrix of the present application includes a composite of silica nanomaterial and polydimethylsiloxane, which makes the black matrix transparent in a normal state (in a planar state) because the optical characteristics of polydimethylsiloxane and silica nanomaterial are similar (for example, the refractive index of silica is 1.475, and the refractive index of polydimethylsiloxane is 1.43, which are very similar); and because the mechanical strength of the polydimethylsiloxane and the silica nano material are greatly different, under the condition of compressive load, the surface of the silica nano particle pattern layer has bending type instability, so that 1D or 2D wrinkles in a grating form are generated and become opaque.

Therefore, when UV light is irradiated in an HVA process in a COA machine, the substrate is in a planar state, the black matrix is in a transparent state, the UV light in the HVA process is not shielded, the polymerization of the liquid crystal material and the additive material is further facilitated, the additive material is ensured to have excellent film forming uniformity, and the phenomenon of poor panel performance caused by poor alignment is avoided.

Because the curved screen is manufactured in a plane mode in the process of manufacturing the curved screen, the module is finally assembled and fixed in a curved mode, after the curved screen is manufactured on the panel, the panel can be subjected to compressive load, so that the black matrix (comprising the silicon dioxide nanoparticle pattern layer and the flexible polydimethylsiloxane film layer) becomes opaque, and finally after the curved screen is applied, the black matrix can be used as a shading structure to play a shading role.

The embodiment of the present application further provides a method for preparing a black matrix for a liquid crystal panel, including the following steps:

providing a substrate base plate;

In one embodiment, the patterned inkjet printing is performed on the black matrix area on the surface of the substrate using a silica nanoparticle solution as a spray liquid, and the substrate is dried at 90 ± 3 ℃ for 30 ± 2 minutes to completely volatilize formamide, thereby forming a silica nanoparticle pattern layer. For example, the drying conditions may be drying at 87 ℃ for 32 minutes; alternatively, the drying conditions may be drying at 93 ℃ for 28 minutes; alternatively, the drying conditions may be drying at 90 ℃ for 30 minutes.

In another embodiment, a polydimethylsiloxane slurry is adopted to form a film on the silicon dioxide nanoparticle pattern layer, the film is baked at 75 +/-2 ℃ for 12 +/-0.5 hours to be solidified, and the film is cooled for 30 +/-5 minutes to form a polydimethylsiloxane film layer after the solidification is completed. For example, the curing conditions may be baking at 73 ℃ for 12.5 hours; alternatively, the curing conditions may be baking at 77 ℃ for 11.5 hours; alternatively, the curing conditions may be baking at 75 ℃ for 12 hours.

In this embodiment, the preparation of the silica nanoparticle solution includes the following steps:

centrifuging the monodisperse silicon dioxide nanometer solution with the diameter of 500 +/-50 nanometers, removing transparent liquid, and collecting precipitates; the mass concentration of the silica in the monodisperse silica nano solution can be 20%; for example, the particle size of the silica may be 450nm, 500nm or 550 nm;

and mixing the precipitate with formamide to obtain a silica nanoparticle suspension with the mass concentration of 20 +/-2%, and performing ultrasonic treatment to ensure complete dispersion to obtain a rigid silica nanoparticle solution for spraying. For example, the mass concentration of silica in the silica nanoparticle suspension may be 18%, 20%, or 22%.

In this example, the preparation of the polydimethylsiloxane slurry includes the following steps:

according to the weight ratio of 8-12: 1 weight ratio of the base agent to the polydimethylsiloxane curing agent to obtain slurry, and carrying out vacuum defoaming to obtain the polydimethylsiloxane slurry. For example, in the preparation of the polydimethylsiloxane slurry, the base and curing agent (polydimethylsiloxane) are mixed in a ratio of 8: 1, mixing; alternatively, the base and polydimethylsiloxane are mixed in a 12: 1, mixing; alternatively, the base and polydimethylsiloxane are mixed in a ratio of 10: 1 by weight ratio.

In one embodiment, the method for preparing the black matrix for the liquid crystal panel comprises the following steps:

providing a substrate base plate;

1mL of monodisperse silica nanoparticle solution (20% w/v) having a diameter of 500nm was centrifuged at 4000rpm for 12 minutes to remove a transparent liquid, and the precipitate was collected; mixing the precipitate with formamide to obtain a 20% silica nanoparticle suspension, and performing ultrasonic treatment for 20 minutes to ensure complete dispersion to obtain a silica nanoparticle solution for spraying;

carrying out patterned inkjet printing on a black matrix area on the surface of the substrate by using a silica nanoparticle solution as a spraying liquid, and drying at 90 ℃ for 30 minutes to completely volatilize formamide to form a rigid silica nanoparticle pattern layer; referring to fig. 5, the silica nanoparticle pattern layer is formed by arranging a plurality of spaced apart, e.g., conventional black matrices;

the preparation of the polydimethylsiloxane slurry comprises the following steps: according to the following steps of 10: 1 weight ratio of the base agent to the polydimethylsiloxane curing agent to obtain slurry, and defoaming the slurry in vacuum for 30 minutes to remove bubbles to obtain polydimethylsiloxane slurry;

forming a film on the rigid silicon dioxide nanoparticle pattern layer by using polydimethylsiloxane slurry, baking the film in a 75 ℃ oven for 12 hours to solidify the film, cooling the film for 30 minutes, and forming a flexible polydimethylsiloxane film after the solidification, wherein please refer to fig. 6;

In summary, the black matrix with the rigid silicon dioxide nanoparticles and the flexible Polydimethylsiloxane (PDMS) is applied to the curved screen instead of the existing black matrix material, so that the problem of shading of the common black matrix caused by limitation of the UV irradiation direction of the HVA process in the COA type liquid crystal panel of the existing curved screen can be effectively solved.

The black matrix for the liquid crystal panel, the preparation method thereof, the substrate and the liquid crystal panel provided in the embodiments of the present application are described in detail above, and a specific example is applied herein to explain the principle and the implementation of the present application, and the description of the embodiments above is only used to help understanding the method and the core concept of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. The black matrix for the liquid crystal panel is characterized by comprising a silicon dioxide nanoparticle pattern layer and a polydimethylsiloxane film layer, wherein the polydimethylsiloxane film layer covers the silicon dioxide nanoparticle pattern layer.

2. The black matrix for a liquid crystal panel according to claim 1, wherein the silica for the silica nanoparticle pattern layer has a refractive index of 1.46 ± 0.02; and/or the presence of a gas in the gas,

the refractive index of the polydimethylsiloxane is 1.43 +/-0.02.

3. The black matrix for a liquid crystal panel according to claim 1 or 2, wherein the diameter of the silica for the silica nanoparticle pattern layer is 500 ± 50 nm.

4. The substrate for the curved-panel liquid crystal panel is characterized by comprising a substrate base plate and a black matrix arranged on the surface of the substrate base plate, wherein the black matrix is the black matrix according to any one of claims 1 to 3.

5. The liquid crystal panel is characterized by comprising a first substrate and a second substrate which are oppositely and parallelly arranged, wherein a black matrix is arranged on one side, facing the second substrate, of the first substrate, the black matrix comprises a silicon dioxide nanoparticle pattern layer and a polydimethylsiloxane film layer, and the polydimethylsiloxane film layer covers the silicon dioxide nanoparticle pattern layer.

6. The liquid crystal panel according to claim 5, wherein the liquid crystal panel is a COA type liquid crystal panel, and a color photoresist layer, a planarization layer and a pixel electrode layer are sequentially disposed on a side of the second substrate facing the first substrate.

7. The liquid crystal panel according to claim 5 or 6, wherein the black matrix is light-transmissive when the liquid crystal panel is in a planar state; and/or the presence of a gas in the gas,

the black matrix is opaque when the liquid crystal panel is in a compressive loaded state.

8. A method for preparing a black matrix for a liquid crystal panel according to any one of claims 1 to 3, comprising the steps of:

providing a substrate base plate;

carrying out patterned inkjet printing on a black matrix area on the surface of the substrate by using a silicon dioxide nanoparticle solution to form a silicon dioxide nanoparticle pattern layer;

forming a film in the black matrix area by adopting polydimethylsiloxane slurry, namely forming a polydimethylsiloxane film layer on the silicon dioxide nanoparticle pattern layer;

9. The method of claim 8, wherein the preparing the silica nanoparticle solution comprises:

centrifuging the monodisperse silicon dioxide nanometer solution with the diameter of 500 +/-50 nanometers, and collecting the precipitate;

mixing the precipitate with formamide to obtain a silica nanoparticle suspension with the mass concentration of 20 +/-2%, and performing ultrasonic treatment to obtain a silica nanoparticle solution for spraying;

and/or, the preparation of the polydimethylsiloxane slurry comprises the following steps:

according to the weight ratio of 8-12: 1 weight ratio of the base agent to the polydimethylsiloxane curing agent to obtain slurry, and carrying out vacuum defoaming to obtain the polydimethylsiloxane slurry.

10. The method of manufacturing a black matrix for a liquid crystal panel according to claim 8 or 9, comprising the steps of:

providing a substrate base plate;

carrying out patterned inkjet printing on a black matrix area on the surface of the substrate by using a rigid silica nanoparticle solution as a spraying liquid, and drying at 90 +/-3 ℃ to volatilize formamide to form a silica nanoparticle pattern layer;

forming a film on the silicon dioxide nano particle pattern layer by adopting polydimethylsiloxane slurry, solidifying at the temperature of 75 +/-2 ℃, and cooling to form a polydimethylsiloxane film layer;