A broadband and wide-angle bionic anti-reflection composite structure and preparation method thereof

Abstract

The invention discloses a broadband wide-angle bionic anti-reflection composite structure and a preparation method thereof, comprising a base layer, a plurality of spherical top cone units and a plurality of mesh grid units, wherein the base layer is provided with a plurality of spherical top cone units and a plurality of mesh grid units, wherein a mesh grid unit is connected between each two adjacent spherical top cone units, and the plurality of spherical top cone units cooperate with the plurality of mesh grid units to form a plurality of open groove structures on the surface of the base layer; by arranging a mesh grid unit between two adjacent spherical top cone units, the arrangement of the spherical top cone units can be broken, so that the spherical top cone units cooperate with the mesh grid units in a disordered state, thereby expanding the angle range of light reflection; and at the same time, the mesh grid structure can further enhance the overall structure's ability to control light, so that more light is gathered between the spherical top cone units and the mesh grid units, thereby further improving the anti-reflection performance of the structure.

Description

Technical Field

[0001] The invention relates to the technical field of optical anti-reflection, and in particular to a broadband and wide-angle bionic anti-reflection composite structure and a preparation method thereof. Background Art

[0002] From spacecraft, infrared detectors to photovoltaic systems, as well as display screens in daily life, medical endoscopes and other mechanical equipment, all face the problem of performance loss caused by reflected light. Although the method of coating single-layer films, double-layer films and multi-layer films on the surface of devices has been proven to effectively reduce reflected light, the anti-reflection surface constructed by the above functional coating is limited by Fresnel's law and cannot achieve excellent anti-reflection performance under the wavelength of natural light (400-800nm) and changing incident angles. Due to this limitation, the stealth performance of military spacecraft and the imaging effect of infrared detectors are only effective within a narrow wavelength and incident angle; photovoltaic systems need to consume additional electricity to compensate for the light energy loss caused by the change in the angle of sunlight. It can be seen that due to the narrow band and inclination of the incident light on the surface of functional devices, the comprehensive performance of precision optical instruments is seriously affected.

[0003] At present, the more typical bionic prototype is the periodic nanopipple structure of the moth eye. This structure has effectively solved the problem of the narrow anti-reflection frequency band of optical films. However, due to its regular arrangement, the moth-eye structure is relatively weak in solving wide-angle anti-reflection problems.

[0004] In view of this, the existing technology still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a broadband wide-angle bionic anti-reflection composite structure and a preparation method thereof, aiming to solve the problem that the existing moth-eye-like structure is relatively weak in solving wide-angle anti-reflection.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] A broadband and wide-angle bionic anti-reflection composite structure, comprising:

[0008] Base layer;

[0009] A plurality of ball-top cone units are arranged at intervals on the surface of the base layer;

[0010] A plurality of mesh units are arranged on the surface of the base layer; a mesh unit is connected between each two adjacent spherical cone units, so that a plurality of open groove structures are formed on the surface of the base layer by the plurality of mesh units.

[0011] Furthermore, the plurality of spherical-top cone units are arranged irregularly.

[0012] Furthermore, the ball-top cone unit comprises:

[0013] A truncated cone body is arranged on the base layer; the top of the truncated cone body is a plane;

[0014] A hemisphere is arranged on the top of the truncated cone; the diameter of the hemisphere is the same as the diameter of the plane.

[0015] Furthermore, the optimization range of the ratio of the height of the hemisphere to the height of the truncated cone is 0.14 to 0.18, and the optimization range of the ratio of the height of the spherical top cone unit to the bottom diameter of the truncated cone is 1.7 to 2.3.

[0016] Furthermore, the height values ​​of the plurality of spherical-top cone units are Gaussian normally distributed.

[0017] Furthermore, the base layer, the spherical cone unit and the mesh unit are all made of high-transmittance optical materials.

[0018] Furthermore, the height of the base layer and the height of the mesh unit are both lower than the height of the spherical top cone unit.

[0019] A method for preparing a broadband and wide-angle bionic anti-reflection composite structure, the method comprising:

[0020] An inverse structure of a composite structure of a spherical cone unit and a mesh grid unit is made on optical glass;

[0021] A single-layer anti-reflection film was prepared by lamination technology;

[0022] The single-layer anti-reflection film is separated by a release agent and external force to obtain a composite structure film of a ball-top cone unit and a grid unit.

[0023] Furthermore, the inverse structure of manufacturing the composite structure of the ball-top cone unit and the grid unit on the optical glass comprises:

[0024] Remove dust from the surface of optical glass using anhydrous ethanol, acetone, and deionized water;

[0025] Remove residual moisture from optical glass through nitrogen treatment;

[0026] Through laser processing technology, an inverse structure of a composite structure of a ball-top cone unit and a grid unit is processed on optical glass;

[0027] The optical glass is cleaned to obtain the inverse structure of the composite structure of the ball-top cone unit and the grid unit.

[0028] Furthermore, the preparation of a single-layer anti-reflection film by laminating technology includes:

[0029] The optical glass is sealed around by using glass glue and transparent glass to form a mold;

[0030] The high permeability polymer and its corresponding curing agent are mixed in a mass ratio of 1:8 to 12 to form a precursor liquid;

[0031] The catalyst is poured into the precursor liquid to improve the fluidity of the highly permeable polymer;

[0032] Slowly pour the precursor liquid into the mold;

[0033] Place the mold in a vacuum drying oven and preset the drying time;

[0034] After the preset drying time, take out the mold and place it in a drying box for drying;

[0035] After drying is completed, the mold is taken out to obtain a single-layer anti-reflection film.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] In the present invention, a plurality of spherical top cone units and a plurality of mesh units are arranged on the base layer, a mesh unit is connected between every two adjacent spherical top cone units, and the plurality of spherical top cone units cooperate with the plurality of mesh units to form a plurality of open groove structures on the surface of the base layer; by arranging a mesh unit between two adjacent spherical top cone units, the arrangement of the spherical top cone units can be broken, so that the spherical top cone units and the mesh units are in a disordered state, thereby increasing the frequency of light reflection; at the same time, the mesh structure can further enhance the overall structure's ability to control light, so that more light is gathered between the spherical top cone units and the mesh units, thereby improving the anti-reflection performance of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0039] Figure 2 It is a schematic diagram of the disordered structure of the ball-top cone unit of the present invention.

[0040] Figure 3 It is a schematic diagram of the structure of the ball-top cone unit and the grid unit of the present invention.

[0041] Figure 4 It is a schematic diagram of the cross structure of the grid unit of the present invention.

[0042] Figure 5 It is a schematic diagram of the parameter structure of the spherical cone unit and the grid unit of the present invention.

[0043] Figure 6 The present invention is a flow chart of the preparation method.

[0044] Figure 7The present invention is a flow chart of the template preparation method.

[0045] Figure 8 The present invention is a flow chart for preparing a single-layer anti-reflection film.

[0046] Fig. 9 It is a schematic diagram of the template structure of the present invention.

[0047] Fig.10 This is a reflectivity curve diagram of the polydimethylsiloxane film before and after structuring of the present invention.

[0048] Fig.11 The reflectivity curve of the structured polydimethylsiloxane film of the present invention at 0° to 75°.

[0049] The numbers in the figure indicate: 1, base layer; 2, spherical cone unit; 21, truncated cone; 22, hemisphere; 3, grid unit. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] In view of the shortcomings of the prior art, this embodiment provides a broadband and wide-angle bionic anti-reflection composite structure and a preparation method thereof, which can be specifically referred to as follows:

[0054] As attached Figure 1 As shown, a broadband wide-angle bionic anti-reflection composite structure includes a base layer 1, a plurality of spherical top cone units 2 and a plurality of grid units 3. The plurality of spherical top cone units 2 and the plurality of grid units 3 are all arranged on the top wall of the base layer 1. The cross-section of the spherical top cone unit 2 increases from top to bottom, similar to the surface of a cone. The grid unit 3 is a rectangular parallelepiped structure, arranged on the surface of the base layer 1 and located between two adjacent spherical top cone units 2. The two ends of the grid unit 3 extend to the inside of the two adjacent spherical top cone units 2 respectively, so that the two adjacent spherical top cone units 2 are in a connected state, that is, a grid unit 3 is connected between every two adjacent spherical top cone units 2. Through the cooperation of the plurality of spherical top cone units 2 and the plurality of grid units 3, a plurality of open slot structures are enclosed on the surface of the base layer 1. The open slots are opened upward and are enclosed by the plurality of spherical top cone units 2 and the plurality of grid units 3.

[0055] By setting a mesh unit 3 between two adjacent spherical-top cone units 2, the arrangement of the spherical-top cone units 2 can be broken, so that the spherical-top cone units 2 and the mesh unit 3 are in a disordered state, that is, the two adjacent spherical-top cones can be two on the left and right, or two obliquely arranged, so that the cooperation between the spherical-top cone units 2 and the mesh unit 3 presents a variety of states, increasing its disordered state and increasing the angle range of light reflection; at the same time, the mesh unit 3 can further enhance the overall structure's ability to control light, so that more light is gathered between the spherical-top cone units 2 and the mesh unit 3. Since the distance between the spherical-top cone units 2 and the mesh unit 3 is relatively close, multiple reflections of the incident light can be achieved, thereby improving the anti-reflection performance of the structure.

[0056] In one embodiment of the present application, both ends of the mesh unit 3 are planes, and the vertical center line of the plane coincides with the center axis of the spherical cone unit 2, so as to facilitate the position confirmation and processing of the mesh unit 3.

[0057] In one embodiment of the present application, as shown in the attached Figure 1 As shown, multiple spherical top cone units 2 can be formed by an array, and a grid unit 3 is arranged between the spherical top cone unit 2 and another spherical top cone unit 2 adjacent to it in the transverse and longitudinal directions. The lengths, heights and widths of the multiple grid units 3 are the same; the side of the base layer 1 away from the spherical top cone unit 2 is an attachment side, which is used to be attached to the surface of the device to be used. The composite structure is used to reduce the light reflection on the surface of the device. The spherical top cone unit 2 can construct a gradient refractive index between the device surface and the air, which can effectively reduce the glare effect on the device surface, and the grid unit 3 can further enhance the overall structure's ability to control light, so that more light is gathered between the spherical top cone structures.

[0058] In this embodiment, as shown in the attached Figure 3 and attached Figure 4 As shown, a grid unit 3 may also be connected between two diagonal spherical top cone units 2. The anti-reflection performance of the composite structure may be further improved by using a plurality of grid units 3.

[0059] In one embodiment of the present application, as shown in the attached Figure 2 As shown, multiple spherical-top cone units 2 can be irregularly arranged on the surface of the base layer 1, that is, each spherical-top cone unit 2 can be arranged arbitrarily with respect to the adjacent spherical-top cone units 2, the heights of the multiple spherical-top cone units 2 may be different from the diameters of their top walls and bottom walls, and the lengths, heights and widths of the grid units 3 between two adjacent spherical-top cone units 2 may be different. Through the irregular arrangement of the multiple spherical-top cone units 2 and the different size parameters of the spherical-top cone units 2 and the grid units 3, the disorder of the composite structure can be further improved, so that the reflection angles of light present different angles, thereby increasing its reflection frequency in the composite structure and improving the anti-reflection performance of the composite structure.

[0060] In this embodiment, as shown in the attached Figure 5 As shown, the height of the spherical top cone unit 2 is H, and the height of the spherical top cone unit 2 is optimized according to the bandwidth of the incident spectrum. The optimization range of H is (0.25-0.5)λ, where λ is the wavelength of the incident light.

[0061] As attached Figure 3 As shown, the spherical top cone unit 2 includes a truncated cone body 21 and a hemispherical body 22. The truncated cone body 21 is arranged on the base layer 1, the top of the truncated cone body 21 is a plane, the vertical section of the truncated cone body 21 is a trapezoid, the hemispherical body 22 is arranged on the top of the truncated cone body 21, and the diameter of the hemispherical body 22 is the same as the diameter of the plane, that is, the hemispherical body 22 cooperates with the truncated cone body 21, and the surface of the truncated cone body 21 is connected to the surface of the hemispherical body 22, which can form a "bullet-shaped" curve; the spherical top cone unit 2 has the most ideal and highly coordinated curve, which can construct a gradient refractive index between the device surface and the air, and effectively reduce the glare effect on the device surface.

[0062] In one embodiment of the present application, as shown in the attached Figure 5As shown, the optimization range of the ratio of the height of the hemisphere 22 to the height of the truncated cone 21 is 0.14 to 0.18, and the optimization range of the ratio of the height of the spherical cone unit 2 to the bottom diameter of the truncated cone 21 is 1.7 to 2.3; the parameters of the spherical cone unit 2 can be optimized according to the bandwidth of the incident spectrum, the height of the hemisphere 22 is h1, the height of the truncated cone 21 is h2, and the ratio of the height of the hemisphere 22 to the height of the truncated cone 21 is K, wherein the optimization range of K is 0.14 to 0.18, specifically, it can be optimized according to the bandwidth of the incident spectrum; the height of the spherical cone unit 2 is H, the bottom diameter of the truncated cone 21 is D, and the ratio of the height of the spherical cone unit 2 to the bottom diameter of the truncated cone 21 is Right now The optimization range is 1.7 to 2.3, and it can be optimized according to the bandwidth of the incident spectrum;

[0063] Specifically, in the natural spectrum band (350-850nm), the incident angle is 0-75°, and SiO2 is selected as the substrate. The design parameters are as follows: the height of the base layer 1 is 50-100nm, the height of the spherical cone unit 2 is 180-240nm, the diameter of the hemisphere 22 (the top plane diameter of the lower truncated cone body 21) is 44-60nm, and the bottom circle diameter of the lower truncated cone body 21 is 90-130nm; the distance between the two spherical cone units 2 (the length of the grid unit 3) is 150-180nm; the grid units 3 are arranged in a regular quadrilateral with a width of 18-25nm and a height of 40-78nm. The base layer 1, the spherical cone unit 2 and the grid unit 3 can be regarded as a whole, and the material is the same as polydimethylsiloxane.

[0064] When light enters the SiO2 surface containing the composite micro-nano structure, the composite structure will construct a gradient refractive index between the optical device and the air, thereby improving the anti-reflection effect in a wide frequency band; on the other hand, the change of the grid unit 3 and the light control effect formed between the grid units 3 will further enhance the wide-angle anti-reflection performance of the SiO2 surface.

[0065] In this embodiment, the height values ​​of the plurality of spherical top cone units 2 are Gaussian normally distributed, that is, the number of heights of the same spherical top cone units 2 conforms to the Gaussian normal distribution, and the number proportion of each height conforms to the Gaussian normal distribution. In the three-dimensional Cartesian coordinate system, at any z point, the total plane area of ​​the spherical top cone unit 2 and the mesh unit 3 is the same. Assuming that the ground of the spherical top cone unit 2 and the mesh unit 3 is confined within a square with a side length of F, the volume fraction of the structure of the spherical top cone unit 2 and the mesh unit 3 satisfies:

[0066]

[0067] in is the average height of the cone grating structure layer.

[0068] Taking the center of the bottom circle of the spherical cone unit as the coordinate origin, the equation of the spherical cone unit in the three-dimensional Cartesian coordinate system is:

[0069]

[0070] Where x, y, z represent the three-dimensional coordinates of a point on the surface of the spherical cone structure unit, r z It represents the distance from a certain point (x, y, z) on the surface of the structural unit to the central axis of the spherical cone structural unit.

[0071] In one embodiment of the present application, the spherical-top cone unit 2 is connected to at least two grid units 3, that is, the spherical-top cone unit 2 located at the boundary position can be connected to the grid units 3 on the left and right sides, and a spherical-top cone unit 2 located at the center of the composite structure can be connected to multiple grid units 3 to form various types of spherical-top cone and grid structures; the grid units 3 are generally arranged in a rectangular or triangular shape, and the random arrangement of the grid units 3 can increase the overall disorder of the composite structure and improve the anti-reflection performance of the composite structure.

[0072] In one embodiment of the present application, as shown in the attached Figure 5 As shown, the height of the base layer 1 and the height of the grid unit 3 are both lower than the height of the ball-top cone unit 2. In the field of micro-nano anti-reflection, the structural layer (i.e., the ball-top cone and the grid structure layer) will bring a gradient refractive index, which can effectively improve the anti-reflection performance of the device surface, while the non-structural layer (i.e., the base layer 1) does not have a similar effect. Therefore, if the height of the base layer 1 is greater than the cone grating structure layer, it is not conducive to improving the anti-reflection performance of the anti-reflection surface; and if the height of the grid unit 3 is higher than the height of the ball-top cone unit 2, the reflection angle range of the incident light will be reduced, and it cannot effectively cooperate with the surface of the ball-top cone unit 2 to achieve wide-angle anti-reflection.

[0073] In this embodiment, the width of the grid unit 3 is a, the height is h3, and the length is b. The structural parameters of the grid unit 3 can be optimized according to the bandwidth of the incident spectrum and the incident angle; specifically, the optimization range of the width a of the grid unit 3 is (0.1-0.2)H, the height h3 is (0.2-0.25)H, and the length is Wherein H represents the height of the spherical cone unit 2, n0 represents the refractive index of the optical device surface, n1 represents the refractive index of air, θ1 represents the incident angle of light, the refractive index of the cone grating structure layer formed by the spherical cone unit 2 and the grid unit 3 is n2, and satisfies n1<n2<n0.

[0074] In this embodiment, the base layer 1, the spherical cone unit 2 and the grid unit 3 are all high-transmittance optical materials; the high-transmittance optical material can be prepared from any one of polydimethylsiloxane, polymethyl methacrylate, ultraviolet light-curable polymer, polystyrene and polyethylene terephthalate, and is mixed with a certain amount of n-hexane solution and solidified.

[0075] As attached Figure 6 As shown, the present invention also provides a method for preparing a broadband wide-angle bionic anti-reflection composite structure, the method comprising:

[0076] S100, manufacturing an inverse structure of a composite structure of a ball-top cone unit and a grid unit on optical glass;

[0077] The inverse structure of the spherical cone unit 2 and the mesh grid unit 3 is processed on the optical glass by processing equipment, and the spherical cone unit 2 and the mesh grid unit 3 are connected to each other.

[0078] As attached Figure 7 and attached Fig. 9 As shown, in step S100, it also includes:

[0079] S110, dust removal from the optical glass surface using anhydrous ethanol, acetone, and deionized water;

[0080] When processing the inverse structure of the ball-top cone unit 2 and the grid unit 3, the optical glass needs to be cleaned first to ensure the cleanliness of the surface; specifically, the optical glass is ultrasonically vibrated cleaned with a variety of solvents such as anhydrous ethanol, acetone, and deionized water to remove dust on the surface.

[0081] S120, removes residual moisture from optical glass through nitrogen treatment;

[0082] After the optical glass is cleaned by ultrasonic vibration, take out the optical glass and treat it with nitrogen to remove the residual moisture on the optical glass to ensure the cleanliness of the optical glass surface.

[0083] S130, through laser processing technology, the inverse structure of the composite structure of the ball top cone unit and the grid unit is processed on the optical glass;

[0084] Using laser processing technology, the design drawings obtained through graphics processing software are imported into the laser direct writing software. The laser beam scanning path and laser processing parameters are generated according to the composite structure size and the preset filling spacing: center wavelength 1000~1100nm, repetition frequency 1~3kHz, pulse width 100~300pS, scanning speed 1~4mm / s, energy density 6~9J / cm 2, the scanning cycle is 1 to 3 μm, during which the visual imaging system is used for detection to ensure that the path of the laser beam is always on the optical glass surface, and finally the expected composite structure template is obtained.

[0085] S140, cleaning the optical glass to obtain an inverse structure of the composite structure of the ball-top cone unit and the grid unit.

[0086] A spray containing anhydrous ethanol and deionized water is used to remove tiny particles and dust generated during the template manufacturing process. At the same time, 0.5% dilute hydrochloric acid and deionized water are used to ultrasonically clean the motherboard to ensure that the sample surface is clean and free of foreign matter. Then, nitrogen is used to remove excess moisture, thereby obtaining an inverse structure of the composite structure of the ball-top cone unit and the grid unit.

[0087] S200, a single-layer anti-reflection film is prepared by lamination technology;

[0088] A single-layer anti-reflection film is prepared on the surface of the template by lamination technology, that is, a film including a base layer 1 and a ball-top cone and a grid structure is obtained.

[0089] As attached Figure 8 As shown, in step S200, it also includes:

[0090] S210, encapsulating the periphery of the optical glass by using glass glue and transparent glass to form a mold;

[0091] A piece of glass is arranged around the optical glass, and the four pieces of glass are in close contact with each other, and the contact gaps are sealed to form a mold.

[0092] S220, mixing a high permeability polymer and a corresponding curing agent in a mass ratio of 1:8 to 12 to form a precursor liquid;

[0093] The high polymer is any one of polydimethylsiloxane, polymethyl methacrylate, ultraviolet light curing polymer, polystyrene and polyethylene terephthalate. Any of the above materials and a curing agent are mixed in a mass ratio of 1:8 to 12 and poured into a beaker. A glass rod is used to stir for 10 to 20 minutes to fully mix them to form a precursor liquid.

[0094] S230, pouring a catalyst into the precursor liquid to improve the fluidity of the highly permeable polymer;

[0095] The catalyst is a n-hexane solution, and n-hexane solutions of different mass fractions (0-15wt%) are added to the precursor liquid to improve the fluidity of the polydimethylsiloxane itself. Subsequently, the polydimethylsiloxane mixed liquid with n-hexane is stirred again for 10-20 minutes.

[0096] S240, slowly pouring the precursor liquid into the mold;

[0097] The prepared precursor liquid is slowly poured into the mold prepared in step S210, so that the high permeability polymer is fully immersed in the anti-reflective composite structure of the template.

[0098] S250, placing the mold in a vacuum drying oven and presetting the drying time;

[0099] The optical glass containing the high-permeability polymer film prepared in step S240 is placed in a vacuum drying oven and evacuated for 1 to 2 hours to ensure that no bubbles remain on the surface of the film.

[0100] S260, after a preset drying time, taking out the mold and placing it in a drying box for drying;

[0101] After 12 hours, take out the mold and place it in a drying oven with a temperature set at 60-80°C for 2-5 hours.

[0102] S270, after the drying is completed, the mold is taken out to obtain a single-layer anti-reflection film.

[0103] After drying, the optical glass is taken out and placed in a dust-free environment to cool for 0.5 to 1.5 hours. The precursor liquid forms a single-layer anti-reflection film in the mold, and the single-layer anti-reflection film can be removed from the motherboard by using a demolding agent and external force. The surface of the film is ultrasonically cleaned (10 to 15 minutes) with anhydrous ethanol and deionized water respectively to remove residues.

[0104] S300, the single-layer anti-reflection film is separated by a release agent and external force to obtain a composite structure film of a ball-top cone unit and a grid unit.

[0105] The single-layer anti-reflection film is separated from the template by using a release agent and external force, thereby obtaining a composite structure film of the ball-top cone unit 2 and the grid unit 3.

[0106] Further, as attached Fig.10 As shown in the figure, the reflectivity of the unstructured polydimethylsiloxane film and the structured polydimethylsiloxane film is compared under the incident light of 350-850nm. It can be seen that the overall reflectivity of the unstructured polydimethylsiloxane film is about 4.5%. After the composite structure is constructed, the overall reflectivity decreases by about 2.7%. At the same time, in the 500-850nm band, the reflectivity decreases more significantly. This data proves that the composite structure has excellent broadband anti-reflection performance.

[0107] Further, as attached Fig.11As shown in the figure, under 433nm incident light, the reflectivity change curve of the structured polydimethylsiloxane film changes from 0 to 75°. It can be seen that with the increase of the angle, the reflectivity shows an upward trend, reaching the highest near 60°, the reflectivity is about 2.63%, and the maximum difference in reflectivity within the wide angle range of 75° is about 1.31%, showing an ideal wide-angle anti-reflection effect.

[0108] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the schemes disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed in this scheme. The description and examples are to be regarded as exemplary only, and the true scope and spirit of the present invention are indicated by the claims.

Claims

1. A broadband and wide-angle bionic anti-reflection composite structure, characterized in that: include: Base layer; A plurality of ball-top cone units are arranged at intervals on the surface of the base layer; A plurality of mesh grid units are arranged on the surface of the base layer; A mesh unit is connected between each two adjacent spherical cone units, so that a plurality of open groove structures are formed on the surface of the base layer by a plurality of the mesh units; The plurality of spherical cone units are arranged irregularly; the lengths, heights and widths of the plurality of mesh grid units connected between the plurality of spherical cone units are at least partially different; The height of the base layer is lower than the height of the spherical top cone unit.

2. The broadband and wide-angle bionic anti-reflection composite structure according to claim 1, characterized in that: The ball-top cone unit comprises: A truncated cone body is arranged on the base layer; the top of the truncated cone body is a plane; A hemisphere is arranged on the top of the truncated cone; the diameter of the hemisphere is the same as the diameter of the plane.

3. The broadband and wide-angle bionic anti-reflection composite structure according to claim 2, characterized in that: The optimized range of the ratio of the height of the hemisphere to the height of the truncated cone is 0.14 to 0.18, and the optimized range of the ratio of the height of the spherical top cone unit to the bottom diameter of the truncated cone is 1.7 to 2.

3.

4. The broadband and wide-angle bionic anti-reflection composite structure according to claim 1, characterized in that: The height values ​​of the plurality of spherical-top cone units are in Gaussian normal distribution.

5. The broadband and wide-angle bionic anti-reflection composite structure according to claim 1, characterized in that: The base layer, the spherical cone unit and the mesh unit are all made of high-transmittance optical materials.

6. The broadband and wide-angle bionic anti-reflection composite structure according to claim 1, characterized in that: The height of the mesh unit is lower than that of the spherical cone unit.

7. A method for preparing a broadband wide-angle bionic anti-reflection composite structure, based on the broadband wide-angle bionic anti-reflection composite structure according to any one of claims 1 to 6, characterized in that: The method comprises: An inverse structure of a composite structure of a spherical cone unit and a mesh grid unit is made on optical glass; A single-layer anti-reflection film was prepared by lamination technology; The single-layer anti-reflection film is separated by a release agent and external force to obtain a composite structure film of a ball-top cone unit and a grid unit; The method of preparing a single-layer anti-reflection film by laminating technology comprises: The optical glass is sealed around by using glass glue and transparent glass to form a mold; The high permeability polymer and its corresponding curing agent are mixed in a mass ratio of 1:8 to 12 to form a precursor liquid; The catalyst is poured into the precursor liquid to improve the fluidity of the highly permeable polymer; Slowly pour the precursor liquid into the mold; Place the mold in a vacuum drying oven and preset the drying time; After the preset drying time, take out the mold and place it in a drying box for drying; After drying is completed, the mold is taken out to obtain a single-layer anti-reflection film.

8. The method for preparing the broadband wide-angle bionic anti-reflection composite structure according to claim 7, characterized in that: The inverse structure of the composite structure of the ball-top cone unit and the grid unit is made on the optical glass, comprising: Remove dust from the surface of optical glass using anhydrous ethanol, acetone, and deionized water; Remove residual moisture from optical glass through nitrogen treatment; Through laser processing technology, an inverse structure of a composite structure of a ball-top cone unit and a grid unit is processed on optical glass; The optical glass is cleaned to obtain the inverse structure of the composite structure of the ball-top cone unit and the grid unit.

Images