A method for manufacturing a multifunctional projection screen having a microstructure array

Abstract

The application discloses a preparation method of a multifunctional projection screen based on a microstructure array, and comprises the following steps: step a, obtaining a gray scale image of a substructure of the multifunctional projection screen by using a matlab algorithm software; the substructure comprises a concave aspheric mirror and a plurality of sharp cone-shaped protrusions arranged periodically around the concave aspheric mirror; step b, collecting gray scale information of the gray scale image by using a 3D laser direct writing lithography technology to perform one-time exposure, and obtaining a photoresist model of the substructure of the multifunctional projection screen based on the microstructure array; step c, periodically and closely arranging a plurality of the photoresist models of the substructure, and preparing a PDMS mold by using the periodically and closely arranged photoresist models of the substructure; step d, obtaining a flexible base of the multifunctional projection screen from the PDMS mold; and step e, plating the flexible base with a nanoscale reflection-increasing film, so as to prepare the multifunctional projection screen based on the microstructure array.

Description

Technical Field

[0001] This invention relates to the field of multifunctional projection screen technology, and in particular to a method for preparing a multifunctional projection screen with a microstructure array. Background Technology

[0002] Currently, projection screens are widely used in our daily lives and various business scenarios. However, traditional projection screens have drawbacks such as low brightness, susceptibility to ambient light interference, and susceptibility to dust and water mist contamination. Therefore, their performance is poor in some outdoor environments, and long-term use may even affect their lifespan.

[0003] In recent years, researchers have shifted their focus to improving the performance of projection screens, hoping to create screens capable of high-definition imaging and good bending performance. This invention aims to effectively and cost-efficiently improve projection screen performance by cleverly incorporating a microstructure array onto the screen. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a method for fabricating a multifunctional projection screen with a microstructure array.

[0005] The present invention discloses a method for fabricating a multifunctional projection screen with a microstructure array, comprising the following steps:

[0006] Step a: Use MATLAB algorithm software to convert and obtain the grayscale image of the substructure of the multifunctional projection screen; the substructure includes a concave aspherical mirror and a plurality of periodically arranged pointed cone-shaped protrusions around the concave aspherical mirror;

[0007] Step b: The grayscale information of the grayscale image is acquired by 3D laser direct writing lithography and exposed once to obtain the photoresist model of the substructure of the multifunctional projection screen based on the microstructure array;

[0008] Step c: Periodically and closely arrange the photoresist models of the multiple substructures, and prepare a PDMS mold using the periodically and closely arranged photoresist models of the multiple substructures;

[0009] Step d: Obtain the flexible substrate for the multifunctional projection screen from the PDMS mold; and

[0010] Step e: A nanoscale anti-reflective coating is deposited on the flexible substrate of the multifunctional projection screen obtained from the PDMS mold, thereby preparing a multifunctional projection screen based on a microstructure array.

[0011] Preferably, step a further includes:

[0012] Step a1: Calculate the parameters of the substructure of the multi-functional projection screen;

[0013] Step a2: Establish the geometric model of the multifunctional projection screen substructure using the parameters; and

[0014] Step a3: Use MATLAB algorithm software to calculate and solve the geometric model parameters to obtain the grayscale image of the substructure.

[0015] Preferably, in step a1, the parameters include: the asphericity and dimensional parameters of a single concave aspherical mirror, the dimensional parameters including aperture and sag; the period length of the periodically arranged plurality of conical protrusions, and the radius and height of the base circle of each conical protrusion; the total width W and total height H of the substructure.

[0016] Preferably, step b further includes:

[0017] Step b1: Centrifuge the photoresist thoroughly in a centrifuge;

[0018] Step b2: Spin-coat photoresist evenly onto a two-inch glass plate;

[0019] Step b3: Place the glass plate coated with photoresist on a heating plate to dry;

[0020] Step b4: Import the grayscale information of the grayscale image into a 3D laser direct-write lithography machine for reading and expose the photoresist; and

[0021] Step b5: Place the exposed photoresist into the developing solution to develop and obtain the photoresist model of the substructure of the multifunctional projection screen.

[0022] Preferably, in step c, the periodic close arrangement refers to the photoresist models of multiple substructures being arranged closely without gaps in the horizontal and vertical directions.

[0023] Preferably, step c further includes:

[0024] Step c1: Prepare the desired PDMS liquid by using PDMS main agent and curing agent, wherein the ratio of the main agent to the curing agent is 10:1;

[0025] Step c2: Place the PDMS liquid in a vacuum chamber to remove excess air bubbles and let it stand.

[0026] Step c3: The PDMS liquid is applied to multiple periodically arranged substructure photoresist models and baked to obtain a PDMS model, which is a mold of the substructure.

[0027] Preferably, step d further includes:

[0028] Step d1: Inject the PDMS liquid and fluorosilane again into the PDMS model, with the fluorosilane content being 60-100uL;

[0029] Step d2: Place the PDMS mold, which has been injected with the PDMS liquid and fluorosilane, into an oven for baking; and

[0030] Step d3: Remove the cured PDMS structure from the PDMS mold to obtain a flexible substrate for a multifunctional projection screen based on a microstructure array.

[0031] Preferably, step e further includes:

[0032] Step e1: Place the flexible substrate of the multifunctional projection screen into a magnetron sputtering instrument to electroplate an anti-reflective film for 40 seconds;

[0033] Step e2: After cooling, remove the flexible substrate of the multifunctional projection screen and let it stand for 4 hours to obtain a multifunctional projection screen based on a microstructure array.

[0034] Preferably, in step e1, the anti-reflective film is an aluminum film.

[0035] The beneficial effects of this invention are: the multifunctional projection screen prepared by the method of this invention has the advantages of high brightness and resistance to ambient light interference, and high cleanliness and resistance to environmental dust pollution. Furthermore, the preparation process of this invention is simple and efficient, and can be used for large-scale production. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, wherein:

[0037] Figure 1 This is a flowchart of a preferred embodiment of the preparation method of a multifunctional projection screen according to the present invention;

[0038] Figure 2 This is a plan view of the substructure of the multifunctional projection screen according to a preferred embodiment of the present invention;

[0039] Figure 3 This is a side view of the substructure of the multifunctional projection screen according to a preferred embodiment of the present invention;

[0040] Figure 4This is a planar schematic diagram of the periodic arrangement of multiple substructures of a multifunctional projection screen according to a preferred embodiment of the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] like Figure 1 As shown, a preferred embodiment of the present invention provides a method for fabricating a multifunctional projection screen based on a microstructure array, comprising the following steps a to e, each of which will be described in detail below.

[0043] Step a: Use MATLAB algorithm software to convert and obtain the grayscale image of the substructure of the multifunctional projection screen; the substructure includes a concave aspherical mirror and a plurality of periodically arranged pointed cone-shaped protrusions around the concave aspherical mirror, and the multifunctional projection screen is composed of a plurality of such substructures arranged periodically and closely. The specific details of the substructure will be described in detail below.

[0044] Step a above further includes steps a1 to a3. Step a1: Parameters of the substructure of the multifunctional projection screen are calculated. These parameters include: the asphericity and dimensional parameters of a single concave aspherical mirror, including its aperture and sag; the periodic length of multiple periodically arranged conical protrusions; and the parameters of each conical protrusion: its base radius and height. The parameters also include the total width W and total height H of the substructure. The total width W refers to the length of the substructure in both the longitudinal and transverse directions, and the total height H refers to the distance from the bottom surface of the concave aspherical mirror to the apex of the conical protrusion. Step a2: A geometric model (i.e., a three-dimensional model) of the multifunctional projection screen substructure is established using these parameters. Step a3: The geometric model parameters are calculated using MATLAB algorithm software to obtain a grayscale image of the substructure.

[0045] Step b: The grayscale information of the grayscale image is acquired using 3D laser direct-write lithography technology, and a single exposure is performed to obtain a photoresist model of the substructure of the multifunctional projection screen based on a microstructure array. Step b further includes the following steps b1 to b5:

[0046] Step b1: Centrifuge the photoresist thoroughly in a centrifuge. Preferably, the centrifugation speed is 10240 rpm, the centrifugation time is 8 minutes, and the centrifugal force is 8000 N.

[0047] Step b2: Spin-coat photoresist evenly onto a two-inch glass plate. Preferably, the spin-coating speed is 650 rpm and the spin-coating time is 30 s.

[0048] Step b3: Place the glass plate coated with photoresist on a heating plate to dry. Preferably, the drying temperature is 95°C and the drying time is 40 minutes.

[0049] Step b4: Import the grayscale information of the grayscale image into a 3D laser direct-write lithography machine for reading and expose the photoresist.

[0050] Step b5: Place the exposed photoresist into the developing solution for development to obtain the photoresist model of the substructure of the multifunctional projection screen. Preferably, the ratio of water to developing solution is 1:3, and the development time is 6 minutes.

[0051] Step c: Periodically and closely arrange the photoresist models of multiple substructures, and fabricate a PDMS (polydimethylsiloxane) mold using the periodically and closely arranged photoresist models of multiple substructures. Here, the periodic and closely arranged means that the photoresist models of multiple substructures are arranged closely together without gaps in the horizontal and vertical directions. The number of substructures can be determined according to the actual size of the projection screen.

[0052] Step c further includes the following steps c1 to c3:

[0053] Step c1: Prepare the desired PDMS liquid using PDMS base agent and curing agent. Preferably, the ratio of PDMS base agent to curing agent is 10:1.

[0054] Step c2: Place the PDMS liquid in a vacuum chamber to remove excess air bubbles and let it stand. Preferably, the degassing time is 20 minutes, and the standing time is 20 minutes. Since the main agent and curing agent need to be stirred after mixing, stirring will generate air bubbles. Placing the mixed PDMS in a vacuum chamber for 20 minutes to remove air bubbles and letting it stand for 20 minutes ensures that no new air bubbles are generated.

[0055] Step c3: The PDMS liquid is applied to a plurality of periodically arranged substructure photoresist models and baked. Preferably, the baking temperature is 60-75℃ and the baking time is 2.5-3.5h to obtain the PDMS model. The PDMS model obtained at this time is a mold of the substructure.

[0056] The next step is step d: obtaining the flexible substrate of the multifunctional projection screen from the PDMS mold. Step d further includes:

[0057] Step d1: Re-inject the PDMS liquid and fluorosilane into the PDMS model, with the fluorosilane content being 80 μL. Preferably, a thin layer of fluorosilane is first covered on the PDMS model. Specifically, a thin layer of fluorosilane is first thermally evaporated to cover the model, and then a layer of PDMS liquid is poured in.

[0058] Step d2: Place the PDMS mold, which has been injected with the PDMS liquid and fluorosilane, into an oven for baking. Preferably, the baking temperature is 60-75℃ and the baking time is 2.5-3.5h.

[0059] Step d3: The cured PDMS structure is peeled off from the PDMS mold to obtain a flexible substrate for a multifunctional projection screen based on a microstructure array. This flexible substrate consists of multiple periodically and closely arranged substructures.

[0060] Finally, step e: A nanoscale anti-reflective coating is deposited onto the flexible substrate of the multifunctional projection screen obtained from the PDMS mold, thereby fabricating a multifunctional projection screen based on a microstructure array. Step e further includes:

[0061] Step e1: Place the flexible substrate of the multifunctional projection screen into a magnetron sputtering apparatus to electroplate an antireflective film. The preferred electroplating time is 40-60 seconds. In step e1, preferably, the antireflective film is a metal film, more preferably, the metal film is an aluminum film. The thickness of the antireflective film is preferably 100 nm to 1 μm.

[0062] Step e2: After cooling, remove the flexible substrate of the multifunctional projection screen and let it stand for a period of 4-12 hours to obtain a multifunctional projection screen based on a microstructure array.

[0063] like Figure 2-4 The structure of a multifunctional projection screen based on a microstructure array, prepared according to the method of the present invention, is shown. The multifunctional projection screen includes: an optical gain layer 10, composed of a plurality of periodically arranged aspherical concave mirrors 11; and a superhydrophobic cleaning layer 20, composed of a plurality of periodically arranged pointed conical protrusions 21, each of which is arranged around one of the aspherical concave mirrors 11. The outer surfaces of the optical gain layer 10 and the superhydrophobic cleaning layer 20 are further coated with a nanoscale antireflective film 30; that is, the outer surfaces of the PDMS material optical gain layer 10 and the superhydrophobic cleaning layer 20 are also coated with a nanoscale antireflective film 30. The optical gain layer 10 of this multifunctional projection screen can achieve the gain function of improving the brightness of the flexible projection screen. The superhydrophobic cleaning layer 20 of the multifunctional projection screen can achieve the self-cleaning function of isolating dust and preventing water mist condensation.

[0064] In each preferred embodiment, the periodic arrangement of the aspherical concave mirrors 11 has a period of 80-90 μm. Preferably, the periodic arrangement of the aspherical concave mirrors 11 is in a four-sided arrangement, that is, there is one aspherical concave mirror 11 on each side, and the center distance is 80-90 μm, that is, the distance between the centers of adjacent aspherical concave mirrors 11 is 80-90 μm. Preferably, the size parameters of a single aspherical concave mirror 11 can be set to the following range values ​​according to light-gathering ability, hydrophobicity, etc., that is, the asphericity of the aspherical concave mirror is -1-0, and the size parameters satisfy: aperture of 60-75 μm and sag of 8-12 μm. In the same projection screen, all the concave mirrors 10 have the same structure and size.

[0065] In each preferred embodiment, the periodic arrangement of the plurality of conical protrusions 21 has a period of 4-6 μm, and the parameters of each conical protrusion 21 satisfy: a base radius of 2-3 μm and a height of 4-7 μm. The spacing and size of the conical protrusions 21 can also be adjusted according to actual needs.

[0066] In each preferred embodiment, such as Figure 2 As shown, the dimensional parameters of each multifunctional substructure, consisting of one aspherical concave mirror 11 and the surrounding plurality of periodically arranged conical protrusions 21, satisfy the following: total width not greater than 90 μm, and total height not greater than 14 μm. In other words, a multifunctional projection screen is composed of multiple such multifunctional substructures arranged periodically and closely in both the longitudinal and transverse directions. The number and arrangement of the multifunctional substructures depend on the size of the multifunctional projection screen.

[0067] Based on the above structure, the multifunctional projection screen based on a microstructure array prepared by the method of the present invention is made of PDMS flexible material and specifically includes a two-layer structure: a gain layer 10 for realizing the optical gain of the projection screen, and a superhydrophobic cleaning layer 20 for realizing superhydrophobic properties; wherein the gain layer 10 is composed of a periodically arranged array of micron-sized aspherical concave mirrors, and the superhydrophobic cleaning layer 20 is composed of periodically spaced pointed conical protrusions 21, wherein the plurality of pointed conical protrusions 21 are respectively arranged around each of the aspherical concave mirrors 11. Figure 3 From the side view, the two-layer structure 10 and 20 are arranged closely together.

[0068] In a preferred embodiment, the dimensional parameters of the gain layer 10 and the superhydrophobic cleaning layer 20 can be set such that the period of each aspherical concave mirror 11 is 85 μm, the asphericity conicity coefficient of each aspherical concave mirror 11 is -0.35, the aperture is 70 μm, and the sag is 10 μm. Additionally, the optimal radius of the base of each conical protrusion 21 is 2.5 μm, the height is 5 μm, and the arrangement period is 5 μm. Twelve conical protrusions 21 can be arranged on one side of each aspherical concave mirror 11. The multifunctional film with the above-mentioned preferred dimensions, i.e., the multifunctional projection screen, can achieve an optical gain more than twice that of a conventional reflective projection screen, a flexible bending range of ±65°, and a water droplet-repellent contact angle of up to 148°.

[0069] As described above, the multifunctional projection screen prepared by the method of the present invention has the advantages of high brightness and resistance to ambient light interference, and high cleanliness and resistance to environmental dust pollution. Furthermore, the preparation process of the method of the present invention is simple and efficient, and can be used for large-scale production.

[0070] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention, which is defined by the claims and their equivalents.

Claims

1. A method for preparing a multifunctional projection screen based on a microstructure array, characterized in that, The preparation method includes the following steps: Step a: Use MATLAB algorithm software to convert and obtain the grayscale image of the substructure of the multifunctional projection screen; the substructure includes a concave aspherical mirror and a plurality of periodically arranged pointed cone-shaped protrusions around the concave aspherical mirror; Step b: The grayscale information of the grayscale image is acquired by 3D laser direct writing lithography and exposed once to obtain the photoresist model of the substructure of the multifunctional projection screen based on the microstructure array; Step c: Periodically and closely arrange the photoresist models of the multiple substructures, and prepare a PDMS mold using the periodically and closely arranged photoresist models of the multiple substructures; Step d: Obtain the flexible substrate for the multifunctional projection screen from the PDMS mold; and Step e: A nanoscale anti-reflective coating is deposited on the flexible substrate of the multifunctional projection screen obtained from the PDMS mold, thereby preparing a multifunctional projection screen based on a microstructure array. Step a further includes: Step a1: Calculate the parameters of the substructure of the multifunctional projection screen; the parameters include: the asphericity and size parameters of a single concave aspherical mirror, the size parameters including aperture and sag; the period length of the periodically arranged plurality of conical protrusions, and the radius and height of the base circle of each conical protrusion; the total width W and total height H of the substructure; Step a2: Establish the geometric model of the multifunctional projection screen substructure using the parameters; and Step a3: Use MATLAB algorithm software to calculate and solve the geometric model parameters to obtain the grayscale image of the substructure.

2. The method of claim 1, wherein the microstructure array-based multi-functional projection screen is prepared by the steps of: Step b further includes: Step b1: Centrifuge the photoresist thoroughly in a centrifuge; Step b2: Spin-coat photoresist evenly onto a two-inch glass plate; Step b3: Place the glass plate coated with photoresist on a heating plate to dry; Step b4: Import the grayscale information of the grayscale image into a 3D laser direct-write lithography machine for reading and expose the photoresist; and Step b5: Place the exposed photoresist into the developing solution to develop and obtain the photoresist model of the substructure of the multifunctional projection screen.

3. The method for fabricating a multifunctional projection screen based on a microstructure array according to claim 1, characterized in that, In step c, the periodic close arrangement refers to the photoresist models of multiple substructures being arranged closely without gaps in the horizontal and vertical directions.

4. The method of claim 1, wherein the microstructure array-based multi-functional projection screen is prepared by the steps of: Step c further includes: Step c1: Prepare the desired PDMS liquid by using PDMS main agent and curing agent, wherein the ratio of the main agent to the curing agent is 10:1; Step c2: Place the PDMS liquid in a vacuum chamber to remove excess air bubbles and let it stand; Step c3: The PDMS liquid is applied to multiple periodically arranged substructure photoresist models and baked to obtain a PDMS model, which is a mold of the substructure.

5. The method of claim 4, wherein the microstructure array-based multi-functional projection screen is prepared by the steps of: Step d further includes: Step d1: Inject the PDMS liquid and fluorosilane again into the PDMS model, with the fluorosilane content being 60-100uL; Step d2: Place the PDMS mold, which has been injected with the PDMS liquid and fluorosilane, into an oven for baking; and Step d3: Remove the cured PDMS structure from the PDMS mold to obtain a flexible substrate for a multifunctional projection screen based on a microstructure array.

6. The method of claim 5, wherein the microstructure array-based multi-functional projection screen is prepared by the steps of: Step e further includes: Step e1: Place the flexible substrate of the multifunctional projection screen into a magnetron sputtering instrument to electroplate an anti-reflective film for 40 seconds; Step e2: After cooling, remove the flexible substrate of the multifunctional projection screen and let it stand for 4 hours to obtain a multifunctional projection screen based on a microstructure array.

7. The method of claim 6, wherein the microstructure array-based multi-functional projection screen is prepared by the steps of: In step e1, the anti-reflective film is an aluminum film.

Images