Reflective Material Mold with Flat-Top Micro Prism Array and Its Preparation Method

Abstract

The present invention discloses a mold for a reflective material with a flat-top microprism array and a preparation method thereof. The mold for the reflective material is formed by a unit flat-top microprism array, and the side surface of the unit flat-top microprism is a quadrilateral. In the present invention, a fine V-shaped groove is milled in the first direction by using a V-shaped cutter. After all the milling in the first direction is completed, the milling enters the next milling direction to mill a fine V-shaped groove, so as to construct a mold for a reflective material with the same unit flat-top microprism array. This preparation method not only reduces the number of milling times, improves the production efficiency of the mold, and reduces the milling difficulty, but also the flat-top microprism array reflective material produced has the excellent property of maintaining a high retroreflective coefficient under large-angle incidence and observation conditions, which helps to improve the visual recognition of reflective signs in sections with a large visual blind area, such as high-speed entrance and exit ramps and interchange curved guiding roads, and improves the safety driving coefficient.

Description

Technical Field

[0001] The present invention relates to the technical field of reflective materials, and particularly to a mold for reflective materials with a flat-top microprism array and a preparation method thereof. Background Art

[0002] The prism technologies in the reflective material industry include full prisms and large-angle microprism reflective films. Among them, full prisms are formed by removing non-reflective parts from the three corners of a triangular pyramid and then re-assembling or re-creating the full prism pyramid structure, both of which are transformations of the corners of the triangular pyramid, forming a pyramid with two quadrilateral sides and one pentagonal side; the existing method for preparing the original mold of a full prism is to complete the assembly or structure re-creation of the full prism unit pyramid under micron-level conditions, and it is extremely difficult to prepare from the aspect of maintaining the integrity and consistency of the pyramid.

[0003] The existing cubic pyramid is a microcrystalline regular angular pyramid formed by injection molding or assembling a mold, forming a pyramid with three quadrilateral sides. Different from full prisms and cubic pyramids, large-angle pyramids still maintain the state of a complete triangular pyramid.

[0004] The large-angle microprism reflective film, i.e., the inclined prism reflective film, achieves a high retroreflective coefficient in the large-angle direction by changing the shape of the side surface of the pyramid and offsetting the apex point of the apex angle while maintaining the apex angle and the corner state of the triangular pyramid. No matter how the shape of the side surface of the pyramid changes, the number of its sides remains unchanged, still being triangular sides of different shapes.

[0005] The existing large-angle microprism reflective films include an inclined triangular pyramid array microprism reflective film with the apex angle inclined in one direction, a different-inclination triangular pyramid array microprism reflective film with inconsistent inclination angles on the side surfaces of the pyramids on both sides of a V-shaped microgroove in the same direction, etc. The original mold preparation method is as follows:

[0006] Using different multiple V-shaped cutters with the same inclination angles on both sides (the inclination angles on both sides of the same V-shaped cutter are the same, and the inclination angles of different V-shaped cutters are different) or using the same multiple V-shaped cutters with different inclination angles on both sides (the inclination angles on both sides of the same V-shaped cutter are different, and the inclination angles of different V-shaped cutters are the same).

[0007] The former requires replacing different V-shaped cutters in different planing directions, and after planing in one direction is completed, entering another planing direction;

[0008] The latter requires the same V-shaped cutter, but needs to alternate planing in different directions. The preparation processes of both are rather cumbersome. Summary of the Invention

[0009] This application provides a reflective material mold with a flat-top microprism array and a preparation method thereof, which solves the technical problem in the prior art that when preparing a mold, different V-shaped cutters need to be replaced or alternate planing needs to be performed in different directions during the preparation process, resulting in a cumbersome preparation process. In this application, a V-shaped cutter is used to plane fine V-shaped grooves in the first direction. After all the planing in the first direction is completed, the next planing direction is entered to plane fine V-shaped grooves, so as to construct a reflective material mold with an array of unit flat-top microprisms.

[0010] This application provides a reflective material mold with a flat-top microprism array. The reflective material mold is formed by an array of flat-top microprisms. The side surface of the flat-top microprism is trapezoidal, and the top surface and the bottom surface of the flat-top microprism are parallel.

[0011] Further, the reflective material mold is formed by an array of unit flat-top microprisms.

[0012] Further, the flat-top microprism has 3 side surfaces.

[0013] Further, the trapezoid is an isosceles trapezoid.

[0014] A preparation method of a reflective material mold with a flat-top microprism array includes the following steps:

[0015] Step (1): Take an original mold substrate, perform pre-treatment on the substrate to reduce roughness, and obtain a treated mold substrate;

[0016] Step (2): Take the treated mold substrate, perform planing on its surface in the first direction, and obtain a planed mold substrate. The planed mold substrate has a number of Va-shaped grooves;

[0017] Step (3): Perform planing on the surface of the mold substrate in the second direction. The angle between the second direction and the first direction is 30° - 75°. The planed mold substrate has a number of Vb-shaped grooves;

[0018] Step (4): Perform planing on the surface of the mold substrate in the third direction. The angle between the third direction and the second direction is 30° - 75°. The planed mold substrate has a number of Vc-shaped grooves, that is, a reflective material mold with an array of flat-top microprisms is obtained.

[0019] Further, it also includes a pre-step, which is carried out before step (1). The pre-step is

[0020] Step (a): Calculate the planing distance: First, design a unit flat-top microprism, and then calculate the numerical values of the side lengths of the unit flat-top microprism;

[0021] Step (b) Simulation: Substitute the values obtained in step (a) into the simulation system to obtain corresponding simulation results. When the results meet the requirement of "the light spot is concentrated within the wide-angle range of 1° observation angle, and there is a visible light spot outside the range of more than 1° observation angle", proceed to step (1). When the results do not meet the requirement, return to step (a).

[0022] Further, it further includes step (A), and step (A) can be implemented in any one of step (2), step (3), and step (4); specifically, step (A) is as follows:

[0023] During the planing process, continuously clean the substrate with a planing fluid.

[0024] Further, it further includes step (5), and step (5) is implemented after step (4). The specific steps are as follows: After planing is completed, deburr the micro-prism reflective material mold of the flat-top micro-prism array and perform ultrasonic cleaning.

[0025] Further, the specific steps of the roughness reduction pretreatment are as follows: Use turning and polishing to reduce the roughness so that the roughness of the substrate surface is below 20 nm;

[0026] The depth H of the Va-shaped groove, the depth H of the Vb-shaped groove, and the depth H of the Vc-shaped groove are all 50 μm - 150 μm;

[0027] The included angles of the Va-shaped groove, the Vb-shaped groove, and the Vc-shaped groove are all 30° - 75°.

[0028] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0029] 1. The preparation method of the complete pyramid is that as the planing depth increases, the pyramid top changes from a large flat top to a small flat top until the flat top finally disappears into a point and becomes a sharp top, and the required cutting depth is deeper. The preparation method of the reflective material mold with a flat-top pyramid array recorded in this application reduces the planing times of the tool to 1 / 2 - 9 / 10 of the original. It not only shortens the time for preparing the original mold, effectively improves the production efficiency of preparing the original mold, but also reduces the tool wear rate and extends the service life of the tool.

[0030] 2. The original mold is replicated multiple times to form a working mold. When using the fabricated reflective material working mold with a flat-top microprism array for cone implantation, the reflective material mold is closely attached to the optical film to construct the reflective layer structure. The cavity depth of the bright (or intaglio) mold of the flat-top microprism array is shallower than that of the bright (or intaglio) mold of the pointed-top microprism array. This not only enables more sufficient filling of the polymer resin in the optical film but also makes it easier to separate the film from the mold, improving production efficiency and further maintaining the integrity of the microprism unit.

[0031] 3. Divergent retroreflection means that the light rays that can be received within a large viewing angle range after the same incident light is reflected by the reflector, indicating that the light produces divergent retroreflection. Refer to Figure 11 , the light irradiates from the vehicle lamp, but after reflection, the visible viewing angle range obtained is larger than the range of the vehicle. In principle, there should be as many reflected light rays as there are incident light rays. However, actually, due to the wave-particle duality of light, the roughness and physical and chemical properties of the reflector, light rays will undergo diffuse reflection, etc., and light rays will be lost. During the actual application process, the position of the driver's eyes receiving the light rays is different from the position of the vehicle lamp emitting the light rays, that is, the observation angle and the incident angle are not the same. This requires a certain diffusion range after the light rays are reflected. In this application, the sharp angle of the pyramid with triangular sides is improved to a flat-top pyramid with trapezoidal sides. In this way, the flat-top pyramid with trapezoidal sides forms divergent retroreflection of the incident light obliquely incident at a large angle inside the pyramid, significantly increasing the large-angle retroreflection coefficient of the prism reflective film and solving the problem of the sharp decline in the retroreflection coefficient of the prism reflective film in the visible large-angle range.

[0032] 4. Solve the problem of the direction sensitivity of the microprism reflective film with consistent alternating yin-yang stripes, and maintain the original appearance of the microprism reflective film in a plane without light and dark alternation.

[0033] 5. The diffusion effect of the flat-top microprism reflective film meets the requirement of maintaining a high retroreflection coefficient and reflective brightness at a large viewing angle, which helps to improve the visibility and recognition of reflective signs on sections with large visual blind spots such as highway ramp entrances and exits, interchange bends, etc., and enhances the safety driving coefficient.

[0034] 6. In order to obtain more reflected light rays, it is necessary to increase the size of the pyramid. However, after the size of the pyramid becomes larger, a greater cone implantation force is required during cone implantation. When the cone implantation force becomes larger, the pyramid will deform, and after deformation, the light rays will go out of the field of view, resulting in a loss of brightness. The flat-top structure of this application can reduce the deformation of the pyramid, making the pyramids of the mold and the reflective film closer to a high degree of consistency, that is, making the light retroreflection of the reflective film as close as possible to the original mold of the design intention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1Schematic diagram of the structural planing dimensions of the flat-top microprism reflective material mold unit according to the embodiment of the present application;

[0036] Figure 2 Schematic diagram of the dihedral angle deviation pyramid array structure with a flat top obtained by cutting off part of the pointed top pyramid;

[0037] Figure 3 Schematic diagram of the light ray structure when the light ray emission direction is not exactly the same as the incident direction;

[0038] Figure 4 Schematic diagram of the light spot distribution with diffusion effect and at an observation angle of 1°;

[0039] Figure 5 Schematic diagram of the calculation result of the stress distribution through simulation;

[0040] Figure 6 Schematic diagram of the planing structure in step 5 of the embodiment of the present application;

[0041] Figure 7 Schematic diagram of the planing structure in step 6 of the embodiment of the present application;

[0042] Figure 8 Schematic diagram of the planing structure in step 7 of the embodiment of the present application;

[0043] Figure 9 Electron microscope image of the reflective material of Comparative Example 1 of the present application;

[0044] Figure 10 Electron microscope image of the reflective material prepared by the method of the embodiment of the present application;

[0045] Figure 11 Schematic diagram of the headlight reflection; Detailed implementation manners

[0046] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the specification and specific implementation manners.

[0047] A method for preparing a flat-top positive-angle microprism reflective material mold includes the following steps:

[0048] Step (1): Calculate the planing distance. First, design the flat-top microprism unit, and then, based on the pointed-top microprism unit, calculate the data of the unit flat-top microprism as follows

[0049] Please refer to Figure 1 , design that the included angles of the bottom triangle of the positive-angle pyramid are all 60°, that is, ∠A = ∠B = ∠

[0050] C = 60°, the triangle at the bottom of the regular pyramid is an equilateral triangle with side length L and height D; the triangle on the side of the regular pyramid is an isosceles right triangle with side length L·sin45°; the height of the pointed regular pyramid is h. The side length of the triangle at the top of the flat-top regular pyramid is l; the height of the flat-top regular pyramid is H. The tool is a V-shaped tool with an inclination angle of θ on both sides.

[0051] According to the conditions provided above, we can obtain the following equations:

[0052] L = D / sin60° ①

[0053] h = L / 2·tan45·sin(90 - θ)° = L / 2·tan45·cosθ ②

[0054] Similarly, we can get:

[0055] h - H = l / 2·tan45·cosθ,

[0056] Furthermore, we can obtain:

[0057] l = 2(h - H) / (tan45°·cosθ)

[0058] = (L·tan45°·cosθ - 2H) / (tan45°·cosθ)

[0059] = L - 2H / (tan45°·cosθ) ③

[0060] Substitute formula ① into formula ③, we get:

[0061] l = D / sin60 - 2H / (tan45°·cosθ) ④

[0062] In summary, the area S of the triangle on the flat top surface of the regular pyramid can be obtained d as

[0063] S d = 1 / 2L·D - 1 / 2(l + L)·H·tanθ·3

[0064] = D 2 / 2sin60° - (D / sin60° - H / tan45°·cosθ)·H·tanθ·3 ⑤

[0065] Based on the above conclusions, select a V-shaped tool with an inclination angle of θ on both sides, where θ is 35.25° and D is 250um, then we can obtain:

[0066] L = 2·D·cot60° = 288.67um

[0067] h = L / 2·tan45°·cosθ = 118.35um

[0068] In actual production, during the process of implanting cones in the optical film, due to the effects of thermal and mechanical factors, the pyramid structure of the metal mold will produce extremely small deformations when transferred to the pyramid of the organic optical material reflective original film. The pyramid of the original film will be smaller and flatter than that of the mold. Therefore, when performing simulation, the numerical values obtained from the calculation results are corrected and applied to the modeling, that is, L = 290um is taken. When H < h, a flat-top regular pyramid will be produced. Therefore, H = 110um is taken, then, l = L - 2H / (tan45°·cosθ) = 21.7um, and l = 22um is taken.

[0069] Step (2): Construct a simulation of the pyramid structure through geometric optical calculation software, set the incident angle of the light β = 4° for analysis, and cut off the array of dihedral angle deviation pyramids with flat tops of the pyramid part with a bottom side length l of 22um (according to the numerical correction result in step (1), the included angles of the three sides of the pyramid are not exactly equal to 90°), as Figure 2 shown; the light emission direction is not exactly the same as the incident direction, as Figure 3 shown; in addition to the increase in the observation angle range, there is also a diffusion effect of some light in a relatively large range of 180°, as Figure 4 shown.

[0070] The above simulation shows that under the ideal conditions of the optical thin film and the polyester resin material of the reflective layer (that is, the physical and chemical parameters of the thin film layer set during modeling, such as the light transmittance, refractive index are optimal, and the surface is absolutely smooth without diffuse reflection and other factors causing light loss), for the microprism reflective film with an array of dihedral angle deviation pyramids with flat tops, "in the wide-angle range of 1° observation angle, the light spots are concentrated, and at the same time, outside the observation angle range greater than 1°, there are visible light spots", as Figure 4 shown.

[0071] Step (3): Conduct a comparative analysis of the simulation of the cone implanting process through finite element analysis software: During the cone implanting process, whether it is hot embossing cone implanting or UV resin photocuring cone implanting, it is all completed under relatively high process temperature conditions. Since the pyramid structure of the pyramid surface of the gravure pyramid mold is flared, wider at the top and narrower at the bottom, for the same-sized pyramids during the filling process of the polymer resin, the apex angle receives greater force than the flat top angle, and the pyramid is more likely to deform. Through simulation, the calculation results of the force distribution are as Figure 5 shown. It can be seen from the figure that the flat top can reduce the force on the pyramid (the darker the color, the larger the value). The force on the top of the apex angle pyramid is much greater than that on the flat top angle pyramid. The large force will cause large deformation of the pyramid, resulting in a dihedral angle deviation (the included angle between the pyramid sides deviates from 90°), changing the light propagation direction and reducing the film brightness. This further shows that the flat top microprism helps to reduce the deformation of the pyramid to a smaller and flatter shape and stabilize the original brightness of the reflective film.

[0072] Furthermore, the cavity depth of the flat-top pyramid is shallower than that of the sharp-top pyramid. From the analysis of hot pressing and filling and the separation of the film (the optical film with implanted pyramids) and the mold (the metal mold with a pyramid array), it is easy to form a complete structure for the flat-top pyramid. However, for the sharp-top pyramid, it is difficult to form a complete structure during filling, and the tip part is easily damaged during the separation of the film and the mold. Therefore, the complete triangular pyramid apex is generally not reflective when deformed or damaged.

[0073] It can be seen that the above results conform to "the light spots are concentrated within the wide-angle range of the 1° observation angle, and at the same time, there are visible light spots outside the observation angle range greater than 1°", and the planing starts.

[0074] Step (4): Take an original mold substrate, reduce the roughness of the original mold substrate by turning and polishing to make the roughness of the substrate surface below 20 nm.

[0075] Step (5): Refer to Figure 6 , take the processed mold substrate, perform planing on its surface along the first direction to obtain the planed mold substrate. There are several Va-shaped grooves on the planed mold substrate, the depth of each Va-shaped groove is 110 um, and the distance between every two adjacent Va-shaped grooves is 250 um.

[0076] Step (6): Refer to Figure 7 , perform planing on the surface of the mold substrate along the second direction. The included angle between the second direction and the first direction is 60°. There are several Vb-shaped grooves on the planed mold substrate, the depth of each Vb-shaped groove is 110 um, and the distance between every two adjacent Vb-shaped grooves is 250 um.

[0077] Step (7): Refer to Figure 8 , perform planing on the surface of the mold substrate along the third direction. The included angle between the third direction and the second direction is 60°, and the included angle between the third direction and the first direction is 120°. There are several Vc-shaped grooves on the planed mold substrate, the depth of each Vc-shaped groove is 110 um, and the distance between every two adjacent Vc-shaped grooves is 250 um.

[0078] During the planing processes of step (4), step (5), step (6), and step (7), continuously clean the substrate with a planing fluid. After planing is completed, remove burrs and perform ultrasonic cleaning to obtain a mold for the flat-top regular pyramid reflective material.

[0079] Experimental test

[0080] The flat-top regular pyramid reflective material mold prepared according to the embodiments of the present application is transferred to an optical film by hot pressing and implanting cones to produce a microprism reflective original film. At the same time, an existing pointed-top pyramid array microprism reflective original film with the same size as the unit microprism is used as a control group, and the experimental data are as follows:

[0081] Using an equilateral triangle pyramid bottom surface with a side length L = 290 um and equal cutting direction angles (∠A, ∠B, ∠C) of 60°, the original molds of pointed-top and flat-top regular pyramid arrays are prepared by cutting with a V-shaped tool with an inclination angle θ = 30.25°. Then, the structures of the two original molds are transferred to an optical film by hot pressing and implanting cones to produce a microprism reflective original film. Taking the Saudi PC film ShatePC-801 and the Longhua PC film longhuaPC-8013R as Comparative Example 1 and Comparative Example 2 respectively. Among them, the experimental results of Comparative Example 1 are shown in Table 1, the results of Comparative Example 2 are shown in Table 2, and the results of the embodiments of the present application are shown in Table 3:

[0082]

[0083] From the data in Table 1, it can be seen that the passing rates of the measured values of the retroreflective coefficient R at the observation angles α = 0.2°, 0.5°, and 1° are 100%, 85.41%, and 0% respectively;

[0084] The passing rates of the averages are 100%, 100%, and 0% respectively.

[0085] When the incident angle β = -4°, as the observation angle α = 0.2° gradually increases, the retroreflective coefficients at α = 0.5° and 1° decrease by 71.87% and 96.29% respectively.

[0086] When the incident angle β = 15°, as the observation angle α = 0.2° gradually increases, the retroreflective coefficients at α = 0.5° and 1° decrease by 74.94% and 96.87% respectively.

[0087] When the incident angle β = 30°, as the observation angle α = 0.2° gradually increases, the retroreflective coefficients at α = 0.5° and 1° decrease by 65.50% and 99.03% respectively.

[0088]

[0089] From the data in Table 2, it can be seen that the passing rates of the measured values of the retroreflective coefficient R at the observation angles α = 0.2°, 0.5°, and 1° are 100%, 89.58%, and 39.58% respectively;

[0090] The passing rates of the averages are 100%, 100%, and 33.33% respectively.

[0091] When the incident angle β = -4°, as the observation angle α = 0.2° gradually increases, at α = 0.5° and 1°, the retroreflection coefficients decrease by 50.68% and 94.41% respectively.

[0092] When the incident angle β = 15°, as the observation angle α = 0.2° gradually increases, at α = 0.5° and 1°, the retroreflection coefficients decrease by 58.02% and 92.46% respectively.

[0093] When the incident angle β = 30°, as the observation angle α = 0.2° gradually increases, at α = 0.5° and 1°, the retroreflection coefficients decrease by 55.69% and 98.03% respectively.

[0094]

[0095] From the data in Table 3, it can be seen that the passing rates of the measured values of the retroreflection coefficient R for the observation angles α = 0.2°, 0.5°, and 1° are 100%, 86.11%, and 88.89% respectively;

[0096] The passing rates of the average values are 100%, 100%, and 100% respectively.

[0097] When the incident angle β = -4°, as the observation angle α = 0.2° gradually increases, at α = 0.5° and 1°, the retroreflection coefficients decrease by 40.50% and 77.32% respectively.

[0098] When the incident angle β = 15°, as the observation angle α = 0.2° gradually increases, at α = 0.5° and 1°, the retroreflection coefficients decrease by 36.21% and 82.21% respectively.

[0099] When the incident angle β = 30°, as the observation angle α = 0.2° gradually increases, at α = 0.5° and 1°, the retroreflection coefficients decrease by 40.52% and 76.78% respectively.

[0100] In summary, for the regular pyramid, within the range of small observation angles or small incident angles, by comparing the three groups of data of Comparative Example 1, Comparative Example 2, and the embodiments of the present application, it shows that the pyramid with the apex part of the complete pyramid has a higher retroreflection coefficient than the flat-top pyramid. However, within the large angle range, the light of the complete pyramid is severely lost, and the retroreflection coefficient drops sharply. Within the standard large angle range, the retroreflection coefficient drops to a level that does not meet the standard.

[0101] The microprisms obtained from Comparative Example 1, Comparative Example 2, and the embodiments of the present application were placed under an electron microscope for observation. Among them, the electron microscope images of Comparative Example 1 and Comparative Example 2 are as Figure 9 shown (there is no difference in the electron microscope images of Comparative Example 1 and Comparative Example 2 observed by the naked eye, so only the image of Comparative Example 1 is placed), and the electron microscope image of the embodiment of the present application is as Figure 10As shown. It is found through observation of the electron microscope image that for the flat-top positive-angle microprism retroreflective material in the embodiment of the present application, due to the existence of the flat top, when the incident light enters the inside of the pyramid within a small angle range, especially when it is irradiated from the front, the position on the surface where the flat top is located has less total internal reflection, and most of the light penetrates through and is not retroreflected back to the detector. Therefore, there will also be obvious non-reflective points in the middle. However, the proportion of the non-reflective position of the flat top in the entire pyramid (the size of the pyramid L = 290 um) is small.

[0102] As described above, only the embodiments using the technical content of this creation are provided. Any modifications and changes made by those skilled in the art using this creation fall within the scope of the patent claimed by this creation, and are not limited to those disclosed in the embodiments.

Claims

1. A mold for a reflective material with a flat-top microprism array, characterized in that, The reflective material mold is formed by a unit flat-top microprism array. The side surface of the unit flat-top microprism is trapezoidal, the top surface and the bottom surface of the unit flat-top microprism are parallel, and the unit flat-top microprism is a flat-top regular triangular microprism.

2. The reflective material mold with a flat-top micro-prism array according to claim 1, characterized in that, The trapezoid is an isosceles trapezoid.

3. The reflective material mold with a flat-top micro-prism array according to claim 2, characterized in that, The two side edges of the isosceles trapezoid are perpendicular to each other.

4. The reflective material mold with a flat-top microprism array according to claim 2, characterized in that, The bottom side length L of the unit flat-top microprism is 288.67 microns, and the height H is 110 microns.

5. A method for preparing a mold of a reflective material with a flat-top microprism array, characterized in that, It includes the following steps: Step (1) Calculate the planing distance: First, design the unit flat-top microprism, and then calculate the numerical values of the side lengths of the unit flat-top microprism. Step (2) Simulation: Substitute the values obtained in step (1) into the simulation system to obtain the corresponding simulation results. When the results meet the requirements of "spot aggregation within the wide-angle range of 1° observation angle, and at the same time, there are visible light spots outside the observation angle range greater than 1°", then proceed to step (3). When the results do not meet the requirements, then go back to step (1). Step (3) Take an original mold substrate, perform pre-treatment to reduce roughness on the substrate to obtain a treated mold substrate. Step (4) Take the treated mold substrate and perform planing on its surface along the first direction to obtain a planed mold substrate. There are several Va-shaped grooves on the planed mold substrate. Step (5) Perform planing on the surface of the mold substrate along the second direction. The angle between the second direction and the first direction is 30° - 75°. There are several Vb-shaped grooves on the planed mold substrate. Step (6) Perform planing on the surface of the mold substrate along the third direction. The angle between the third direction and the second direction is 30° - 75°. There are several Vc-shaped grooves on the planed mold substrate, that is, the reflective material mold with a flat-top microprism array described in any one of claims 1 to 4 is obtained.

6. The preparation method of the reflective material mold with a flat-top micro prism array according to claim 5, characterized in that, It further includes step (A), and step (A) can be implemented in any one of step (4), step (5), and step (6). The specific content of step (A) is: During the planing process, continuously clean the substrate with a planing fluid.

7. The preparation method of the reflective material mold with a flat-top micro-prism array according to claim 5, characterized in that It further includes step (7), and step (7) is implemented after step (6). The specific steps are: After planing, deburr the microprism-shaped reflective material mold of the flat-top microprism array and perform ultrasonic cleaning.

8. The preparation method of the reflective material mold with a flat-top microprism array according to claim 5, characterized in that The specific steps of the pre-treatment to reduce roughness are: Use turning and polishing to reduce roughness so that the roughness of the substrate surface is below 20 nm. The depth H of the Va-shaped groove, the depth H of the Vb-shaped groove, and the depth of the Vc-shaped groove are all 50 um - 150 um. The angles of the Va-shaped groove, the Vb-shaped groove, and the Vc-shaped groove are all 30° - 75°.

9. A reflective material with a flat-top regular triangular microprism array prepared by the mold described in any one of claims 1 to 4.

10. The reflective material with a flat-top regular triangular microprism array according to claim 9, which is a reflective film.

Images