Microprism reflective film with combination of three triangular pyramids and manufacturing method of mold of microprism reflective film

Abstract

The invention relates to a microprism reflective film with three kinds of triangular pyramid combinations and a manufacturing method of a mold of the microprism reflective film, the surface of the microprism reflective film is formed by an array of identical parallelogram unit bodies (1), each parallelogram unit body (1) is composed of four identical triangular pyramids A, one triangular pyramid B and three identical triangular pyramids C, the directions of the four triangular pyramids A and the directions of the three triangular pyramids C and the triangular pyramids B form 180 degrees, and the three triangular pyramids C and the triangular pyramids B are arranged among the four triangular pyramids A in a staggered manner; the bottom surfaces of the triangular pyramids A, B and C are the same equilateral triangles, the inclination angles of the three pyramids of each triangular pyramid A are alpha / 2, the inclination angles of the three pyramids of each triangular pyramid B are beta-alpha / 2, and the inclination angles of the three pyramids of each triangular pyramid C are alpha / 2, alpha / 2 and beta-alpha / 2 respectively. According to the method, the performance under different application conditions can be reasonably optimized, so that wide-angle performance improvement and optimization and balance of overall comprehensive performance can be realized.

Description

Technical field: The invention relates to a micro-prismatic reflective film with three triangular pyramid combinations and a method for manufacturing a mold thereof. Background technology: A triangular pyramid widely used on the market has an equilateral triangle base and three reflecting surfaces at 90-degree angles to each other. Figure 1 As shown; Another triangular pyramid has an isosceles triangle base and a corner reflector structure with three reflecting surfaces at 90 degrees to each other.

[0001] Currently, the above-mentioned microprismatic reflective film has only one optical design variable, and it is difficult to obtain different incident angles and observation angles (especially wide angles) to achieve simultaneous improvement of retroreflective performance at different azimuth angles, as well as a balance between retroreflective performance at different incident angles and observation angles (especially wide angles and small incident angles), and a balance between retroreflective performance at different azimuth angles (such as 0 degrees, 90 degrees, and 180 degrees).

[0002] In the prior art, to achieve isotropic uniformity in the retroreflective performance of reflective sheeting at different azimuth angles, four types of reflective sheeting nickel molds are typically manufactured by mechanically interlocking and splicing two reflective sheeting nickel molds with different orientations, one at 0 degrees and the other at 90 degrees, to create a roller master mold. This method achieves control of the retroreflective performance of the reflective sheeting (e.g., improving wide-angle performance) by slightly adjusting an angle to deviate from the standard corner cone reflector structure. However, this method is very cumbersome to manufacture, has large mechanical errors, and is difficult to achieve the desired effect.

[0003] In addition, although the retroreflective performance of the microprismatic reflective film using full prisms (US 3M) is 50% higher than that of the microprismatic reflective film using triangular pyramids (or the effective reflection area of the triangular pyramid reflective film is 66.67% of the effective reflection area of the full pyramid reflective film), the mold structure of the full pyramid reflective film (such as Chinese patent numbers 2015107772604 and 201811202555.9) is very complex and difficult to manufacture. In addition, due to mold manufacturing errors, the reflective performance is much lower than expected, which limits its promotion and application.

[0004] In response to the above-mentioned shortcomings, the applicant applied for "Retro-reflective microprism array structure and its manufacturing method" (Announcement No. CN 117930406 A) in March 2024 and "Manufacturing method of microprismatic reflective film with double triangular pyramid combination structure and its mold" (Announcement No. CN118759624B) in September 2024.

[0005] Among them, the “retro-reflective microprism array structure and its manufacturing method” is more convenient to manufacture than patents 2015107772604 and 201811202555.9, avoids the difficulty of secondary clamping and special-shaped surface processing, and ensures the quality of the finished product. However, when making through holes on the second substrate in the processing process, it is necessary to drill holes one by one (such as Figure 1 As shown in the figure, the microprismatic reflective sheeting is processed by wire cutting, but the processing steps are still relatively cumbersome, and the corner cones formed by the processing are all regular triangular pyramids with the same inclination angle. The optical design variable of the microprismatic reflective sheeting is only one, and it is difficult to obtain different incident angles and observation angles. That is, such microprismatic reflective sheeting is mainly used for Class IV reflective sheeting with low performance requirements. When used for Class V reflective sheeting, the retroreflection coefficient cannot meet the standard requirements under the conditions of large observation angles and large incident angles. Among them, the "Manufacturing method of micro-prismatic reflective film with a double triangular pyramid combination structure and its mold" proposes using two tools with tool design angles of α and β to process two micro-prismatic reflective films with a triangular pyramid combination structure on the same mold substrate. After using the first tool with a tool angle of α to process the large triangular pyramid, the second tool with a tool angle of β is used for processing. According to the design requirements, the tool orientation is adjusted so that the inclination angles of the three corner cone surfaces of the central triangular pyramid are all β / 2. At this time, the inclination angles of the two corner cone surfaces of the corner triangular pyramid are α / 2, and the inclination angle of the third corner cone surface in the middle is β / 2. Although by adjusting the angle variables of the triangular pyramid located in the center, the wide-angle performance of the reflective film can be optimized to a certain extent, or the performance of the reflective film at 0 degrees and 90 degrees can be optimized to a certain extent, the micro-prismatic reflective film obtained therefrom still has the disadvantage of insufficient freedom in optical design optimization. Summary of the invention: In view of the above-mentioned problems, the purpose of the present invention is to provide a method for manufacturing a microprismatic reflective film having a combination of three triangular pyramids and a mold thereof. The method for manufacturing a microprismatic reflective film having a combination of three triangular pyramids and a mold thereof is rationally designed, can further increase the degree of freedom of optical design, and is conducive to meeting the performance indicators of more different application conditions.

[0006] The technical solutions of the present invention are as follows: The present invention provides a microprismatic reflective sheeting comprising three triangular pyramid combinations, characterized in that: the surface of the microprismatic reflective sheeting is formed by an array of identical parallelogram units, each of which is composed of four identical triangular pyramids A, one triangular pyramid B, and three identical triangular pyramids C. The orientations of the four triangular pyramids A are 180 degrees relative to the orientations of the three triangular pyramids C and the triangular pyramid B, and the three triangular pyramids C and the triangular pyramid B are staggered between the four triangular pyramids A. The bases of the triangular pyramids B and C are identical equilateral triangles, the inclination angles of the three pyramidal faces of each triangular pyramid A are all α / 2, the inclination angles of the pyramidal faces of the triangular pyramid B are all β-α / 2, and the inclination angles of the three pyramidal faces of the triangular pyramid C are α / 2, α / 2, and β-α / 2, respectively.

[0007] Preferably, the above-mentioned triangular pyramids A are triangular pyramid A1, triangular pyramid A2, triangular pyramid A3 and triangular pyramid A4, respectively; the triangular pyramids C are triangular pyramid C1, triangular pyramid C2 and triangular pyramid C3, respectively; the first row of parallelogram unit bodies are triangular pyramid A3, triangular pyramid C1, triangular pyramid A4 and triangular pyramid C2, respectively; the second row of parallelogram unit bodies are triangular pyramid A1, triangular pyramid B, triangular pyramid A2 and triangular pyramid C3, respectively; and the orientations of adjacent triangular pyramids are 180 degrees to each other.

[0008] Preferably, the pyramidal surface A101 of the triangular pyramid A1 is coplanar with the pyramidal surface A201 of the triangular pyramid A2, the pyramidal surface C101 of the triangular pyramid C1 is coplanar with the pyramidal surface C201 of the triangular pyramid C2, the pyramidal surface A102 of the triangular pyramid A1 is coplanar with the pyramidal surface A301 of the triangular pyramid A3, the pyramidal surface C301 of the triangular pyramid C3 is coplanar with the pyramidal surface C202 of the triangular pyramid C2, the pyramidal surface A202 of the triangular pyramid A2 is coplanar with the pyramidal surface A301 of the triangular pyramid A3 02, the pyramidal surface C302 of triangular pyramid C3 is coplanar with the pyramidal surface C102 of triangular pyramid C1, the pyramidal surface A303 of triangular pyramid A3 is coplanar with the pyramidal surface A401 of triangular pyramid A4, the pyramidal surface B001 of triangular pyramid B is coplanar with the pyramidal surface C303 of triangular pyramid C3, the pyramidal surface B002 of triangular pyramid B is coplanar with the pyramidal surface C103 of triangular pyramid C1, and the pyramidal surface A203 of triangular pyramid A2 is coplanar with the pyramidal surface A402 of triangular pyramid A4.

[0009] The present invention provides a method for manufacturing a mold for a microprismatic reflective film having a combination of three triangular pyramids, which is used to manufacture the mold for the microprismatic reflective film having a combination of three triangular pyramids, and is characterized in that: A method for manufacturing a mold for a microprismatic reflective film having a combination of three triangular pyramids, which is used to manufacture a mold for a microprismatic reflective film having a combination of three triangular pyramids. The mold base K1 is horizontally mounted on a workbench K2. The workbench can move the mold base along the horizontal X-axis and Y-axis. The B-axis turntable on the workbench can rotate the mold base around the normal B-axis of the mold base. A spindle K3 and a flying cutter disk K4 fixedly connected to the spindle are located above the mold base. A tool K5 is mounted on the flying cutter disk. The tool can rotate around the Y-axis driven by the spindle. The specific steps during manufacturing are as follows: Step 1: Rotate the mold substrate on the B-axis turntable to 0 degrees (or 180 degrees), and use the first tool with a tool angle of α installed on the fly cutter head to machine the two side cone surfaces of the parallelogram unit, namely, the cone surface A101 of the triangular pyramid A1, the cone surface A201 of the triangular pyramid A2, the cone surface C101 of the triangular pyramid C1, and the cone surface C201 of the triangular pyramid C2, with an inclination angle of α / 2; Step 2: Rotate the mold substrate on the B-axis turntable to 120 degrees (or 300 degrees), and use the first tool with a tool angle of α installed on the fly cutter head to machine the other two cone surfaces of the parallelogram unit, namely, the cone surface A102 of the triangular pyramid A1, the cone surface A301 of the triangular pyramid A3, the cone surface C301 of the triangular pyramid C3, and the cone surface C202 of the triangular pyramid C2, whose inclination angle is also α / 2; Step 3: Rotate the mold substrate on the B-axis turntable to 240 degrees (or 60 degrees), and use the first tool with a tool angle of α installed on the fly cutter disc to machine the two diagonal conical surfaces of the parallelogram unit 1, namely, the conical surface A202 of the triangular pyramid A2, the conical surface A302 of the triangular pyramid A3, the conical surface C302 of the triangular pyramid C3, and the conical surface C102 of the triangular pyramid C1, whose inclination angle is also α / 2; Step 4: Replace the second tool with a cutting angle of β on the cutter disc, and adjust the tool to produce a deflection angle △, that is, the symmetry center plane of the second tool forms a deflection angle △ with the normal plane of the mold substrate, and △ is not zero, so that the inclination angle of the blade on one side of the tool angle is β / 2+△=α / 2, and the inclination angle of the blade on the other side is β / 2-△=β-β / 2-△=β-(β / 2+△)=β-α / 2; based on the structure processed in step 3, rotate the mold substrate to 0 degrees (or 180 degrees), and then use the adjusted second tool to process the pyramid surface B001 of triangular pyramid B and the pyramid surface C303 of triangular pyramid C3, whose inclination angle is β-α / 2; at the same time, form the pyramid surface A303 of triangular pyramid A3 and the pyramid surface A401 of triangular pyramid A4, whose inclination angle is α / 2; Step 5: Rotate the mold substrate to 120 degrees (or 300 degrees) and use the adjusted second tool to form the pyramid surface B002 of triangular pyramid B and the pyramid surface C103 of triangular pyramid C1, with an inclination angle of β-α / 2. Simultaneously, form the pyramid surface A203 of triangular pyramid A2 and the pyramid surface A402 of triangular pyramid A4, with an inclination angle of α / 2. Step 6: Rotate the mold substrate to 240 degrees (or 60 degrees) in sequence, and use the adjusted second tool to machine the pyramid surface B003 of triangular pyramid B and the pyramid surface C203 of triangular pyramid C2, with an inclination angle of β-α / 2. Simultaneously, machine the pyramid surface A103 of triangular pyramid A1 and the pyramid surface A403 of triangular pyramid A4, with an inclination angle of α / 2. At this point, the mold for the microprismatic reflective film composed of three different triangular pyramid structures, namely, triangular pyramid A with an inclination angle of α / 2, triangular pyramid B with an inclination angle of β-α / 2, and triangular pyramid C with inclination angles of α / 2, α / 2, and β-α / 2, has been processed and formed.

[0010] The present invention has the following technical advantages.

[0011] From an optical design perspective, increased optical design freedom means that optical systems can simultaneously meet performance indicators for a wider range of different application conditions. For high-performance Class V reflective sheeting, improving its wide-angle performance at large observation angles and large incident angles, as well as its performance at 90-degree and 0-degree azimuth orientations, and optimizing and balancing these performances have always been the focus of research and development in Class V reflective sheeting technology. The reflective sheeting of the present invention comprises three triangular pyramids: a triangular pyramid A with a pyramidal surface inclination angle of α / 2, a triangular pyramid B with a pyramidal surface inclination angle of β-α / 2, and a "hybrid" triangular pyramid C with three pyramidal surface inclination angles of α / 2, α / 2, and β-α / 2, respectively. This achieves design freedom for the three triangular pyramids, with the area proportions of the three triangular pyramids A, B, and C being 50%, 12.5%, and 37.5%, respectively. This allows for optimal performance optimization for different application conditions, thereby achieving wide-angle performance improvements unattainable with conventional microprismatic reflective sheeting with triangular pyramid unit structures or dual triangular pyramid combination structures, as well as optimizing and balancing overall comprehensive performance.

[0012] In addition, the second tool used in the present invention is a β tool, and its deflection angle is selected as △ = α / 2-β / 2 (i.e., the symmetry center plane of the second tool and the normal plane of the mold substrate form a deflection angle △), so as to obtain a typical reflective film with a combination structure of three triangular pyramids; The mold manufacturing of the reflective film of the present invention is equivalent to using a second tool with an asymmetric structure design to process and form the film. One side of the mechanical center axis of the tool is α / 2, and the other side is β-α / 2. In fact, it is equivalent to using a tool with a blade angle of β plus a deflection angle △=α / 2-β / 2 to process and form the film. By selecting different deflection angle values △ but not zero, it is expected to obtain a micro-prismatic reflective film design composed of three different triangular pyramids (with varying inclination angles of the pyramidal surfaces), thereby improving the overall performance of the reflective film and optimizing the wide-angle performance, small-angle performance, and 90-degree and 0-degree orientation performance. Description of the drawings: The present invention will be further described below with reference to the accompanying drawings; Figure 1 It is a schematic diagram of the structure of an existing reflective microprism monomer; Figure 2 It is a schematic diagram of the three-dimensional structure of the parallelogram unit body of the present invention; Figure 3 yes Figure 2 The main view; Figure 4 It is a three-dimensional schematic diagram of the mold substrate placed on the workbench for processing; Figure 5 It is a schematic diagram of the cross-sectional structure of the die substrate during fly cutting; Figure 6 3D schematic diagram of the finished mold of the microprismatic reflective film of the present invention; Figure 7 yes Figure 6 The main view (for intuitive viewing, the numbers in the figure correspond to each other) Figure 3 the number of the reflective film); Figure 8 This is a schematic diagram of the three-dimensional structure of the mold base material when it is not processed; Figure 9 yes Figure 8 The main view; Figure 10 yes Figure 8 The front view of the mold substrate after being processed in step 1; Figure 11 yes Figure 10 The front view of the mold substrate after processing in step 2; Figure 12 yes Figure 11 The front view of the mold substrate after processing in step 3; Figure 13 yes Figure 12 Stereoscopic image of Figure 14 yes Figure 12 The front view of the mold substrate after processing in step 5; Figure 15 yes Figure 14 Schematic diagram of the three-dimensional structure; Figure 16 yes Figure 14 The front view of the mold substrate after processing in step 7; Figure 17 yes Figure 16 Schematic diagram of the three-dimensional structure; Figure 18 yes Figure 16 The front view of the mold substrate after processing in step 7; Figure 19 yes Figure 18 A schematic diagram of the three-dimensional structure of the mold product of the present application (i.e., a schematic diagram of the three-dimensional structure of the mold product of the present application). Specific implementation method: The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0013] like Figure 2 、 3 As shown, the present invention has a microprismatic reflective sheeting with three combinations of triangular pyramids. The surface of the microprismatic reflective sheeting is formed by an array of identical parallelogram units 1. Each parallelogram unit 1 is specifically composed of four identical triangular pyramids A, one triangular pyramid B, and three identical triangular pyramids C. The triangular pyramids A are triangular pyramids A1, A2, A3, and A4, and the triangular pyramids C are triangular pyramids C1, C2, and C3. The first row of parallelogram units is arranged in sequence as triangular pyramid A3, C1, A4, and C2, and the second row of parallelogram units is arranged in sequence as triangular pyramid A1, B, A2, and C3. The orientations of adjacent triangular pyramids are 180 degrees to each other.

[0014] The directions of the four triangular pyramids A are 180 degrees to those of the three triangular pyramids C and the triangular pyramid B, and the three triangular pyramids C and the triangular pyramid B are staggered between the four triangular pyramids A.

[0015] The bases of triangular pyramids B and C are both identical equilateral triangles. The inclination angles of the three corner pyramid surfaces of each triangular pyramid A are all α / 2, the inclination angles of the corner pyramid surfaces of triangular pyramid B are all β-α / 2, and the inclination angles of the three corner pyramid surfaces of triangular pyramid C are α / 2, α / 2, and β-α / 2, respectively. In one embodiment, α=70.50 degrees and β=70.43 degrees.

[0016] The pyramidal surface A101 of the triangular pyramid A1 is coplanar with the pyramidal surface A201 of the triangular pyramid A2, the pyramidal surface C101 of the triangular pyramid C1 is coplanar with the pyramidal surface C201 of the triangular pyramid C2, the pyramidal surface A102 of the triangular pyramid A1 is coplanar with the pyramidal surface A301 of the triangular pyramid A3, the pyramidal surface C301 of the triangular pyramid C3 is coplanar with the pyramidal surface C202 of the triangular pyramid C2, the pyramidal surface A202 of the triangular pyramid A2 is coplanar with the pyramidal surface A302 of the triangular pyramid A3 Coplanar, the pyramidal surface C302 of the triangular pyramid C3 is coplanar with the pyramidal surface C102 of the triangular pyramid C1, the pyramidal surface A303 of the triangular pyramid A3 is coplanar with the pyramidal surface A401 of the triangular pyramid A4, the pyramidal surface B001 of the triangular pyramid B is coplanar with the pyramidal surface C303 of the triangular pyramid C3, the pyramidal surface B002 of the triangular pyramid B is coplanar with the pyramidal surface C103 of the triangular pyramid C1, and the pyramidal surface A203 of the triangular pyramid A2 is coplanar with the pyramidal surface A402 of the triangular pyramid A4.

[0017] The specific processing method for the mold used to manufacture the aforementioned microprismatic reflective film having the three triangular pyramid combinations is as follows.

[0018] like Figure 4 As shown, the mold base K1 is fixedly mounted horizontally on a workbench K2. The workbench can drive the mold base to move along the horizontal X-axis and Y-axis, and the B-axis turntable on the workbench can drive the mold base to rotate around the normal B-axis of the mold base. A spindle K3 and a flying cutter disk K4 fixedly connected to the spindle are provided above the mold base. The spindle K3 can be driven by an existing machine tool. A tool K5 is installed on the flying cutter disk. The tool can rotate around the Y-axis driven by the spindle. The specific steps of manufacturing are as follows: Step 1: Rotate the mold base on the B-axis turntable to 0 degrees (or 180 degrees) (i.e. Figure 9 As shown in the figure), the first type of tool with a tool angle α installed on the fly cutter disc is used to machine the two side cone surfaces of the parallelogram unit body (i.e. Figure 10 The upper and lower cone surfaces of the triangular pyramid A1, the workbench drives the mold substrate to move along the X-axis during the processing), that is, the cone surface A101 of the triangular pyramid A1, the cone surface A201 of the triangular pyramid A2, the cone surface C101 of the triangular pyramid C1, and the cone surface C201 of the triangular pyramid C2, whose inclination angle is α / 2, as shown in FIG. Figure 10 shown.

[0019] Step 2: Rotate the mold base material on the B-axis turntable to 120 degrees (or 300 degrees) (i.e. Figure 9 In the state shown, rotate 120 degrees (or 300 degrees) counterclockwise around the center), and use the first type of tool with a tool angle of α installed on the fly cutter disc to machine the other two sides of the parallelogram unit (i.e. Figure 11 The left and right cone surfaces of the triangular pyramid A1, the cone surface A102 of the triangular pyramid A3, the cone surface C301 of the triangular pyramid C3 and the cone surface C202 of the triangular pyramid C2 also have an inclination angle of α / 2. Figure 11 shown.

[0020] Step 3: Rotate the mold base material on the B-axis turntable to 60 degrees (or 240 degrees) (i.e. Figure 9 In the state shown, rotate 60 degrees (or 240 degrees) counterclockwise around the center, and use the first type of tool with a tool angle of α installed on the fly cutter disc to machine the two diagonal cone surfaces of the parallelogram unit 1, namely the cone surface A202 of the triangular pyramid A2, the cone surface A302 of the triangular pyramid A3, the cone surface C302 of the triangular pyramid C3 and the cone surface C102 of the triangular pyramid C1, whose inclination angle is also α / 2, as shown in FIG. Figure 12 、 13 shown.

[0021] Step 4: Replace the second tool with a cutting angle of β on the fly cutter disc of the working spindle, and adjust the tool to produce a deflection angle △, that is, the symmetrical center plane of the second tool forms a deflection angle △ with the normal surface of the mold substrate, such as Figure 5 As shown; the inclination angle of the blade on one side of the blade corner is β / 2+△=α / 2, and the inclination angle of the blade on the other side is β / 2-△=β-β / 2-△=β-(β / 2+△)=β-α / 2; based on the structure after step 3, the mold substrate is rotated to the 0 degree (or 180 degree) position (i.e. Figure 9 As shown in the figure), the adjusted second tool is used to form the pyramidal surface B001 of the triangular pyramid B and the pyramidal surface C303 of the triangular pyramid C3, whose inclination angle is β-α / 2; at the same time, the pyramidal surface A303 of the triangular pyramid A3 and the pyramidal surface A401 of the triangular pyramid A4 are formed, whose inclination angle is α / 2; Figure 14 、 15 shown.

[0022] Step 5: Rotate the mold substrate to 120 degrees (or 300 degrees) in sequence, and use the second tool adjusted above to process and shape the pyramid surface B002 of triangular pyramid B and the pyramid surface C103 of triangular pyramid C1, whose inclination angle is β-α / 2. At the same time, shape the pyramid surface A203 of triangular pyramid A2 and the pyramid surface A402 of triangular pyramid A4, whose inclination angle is α / 2, as shown in FIG. Figure 16 、 17 shown.

[0023] Step 6: Finally, rotate the mold substrate to 240 degrees (or 60 degrees) in sequence, and use the second type of tool adjusted above to form the pyramid surface B003 of triangular pyramid B and the pyramid surface C203 of triangular pyramid C2, whose inclination angle is β-α / 2; at the same time, form the pyramid surface A103 of triangular pyramid A1 and the pyramid surface A403 of triangular pyramid A4, whose inclination angle is α / 2, as shown in FIG. Figure 18 、 19 As shown, Figure 18 、 19 That is, the structural diagram of the finished mold of this application, Figure 18 、 19 and Figure 6 、 7 They are all schematic diagrams of the structure of the mold used to make the reflective film of the present application. The shape and size of the mold obtained by the above method are the same as the reflective film formed by the subsequent production of the mold. In order to facilitate intuitive viewing, Figure 7 The labels and Figure 2 The same reference numerals are used to reflect the one-to-one correspondence between the mold and the reflective film.

[0024] At this point, the mold of the micro-prismatic reflective film composed of three different triangular pyramid structures, namely triangular pyramid A (with an inclination angle of α / 2), triangular pyramid B (with an inclination angle of β-α / 2), and triangular pyramid C (with inclination angles of α / 2, α / 2, and β-α / 2, respectively), has been processed and formed. Figure 18 、 19 shown.

[0025] Specific processing example: The first tool has a tool angle of α = 70.50 degrees; the second tool is a symmetrical tool with β = 70.43 degrees. By adjusting the tool deflection angle △ = 0.035 degrees, the tool angle on one side is 35.25 degrees, and the other side is 35.18 degrees. When processing, the α tool is used first, and the B-axis rotation angle is 0 degrees (or 180 degrees), 60 degrees (or 240 degrees), 120 degrees (or 300 degrees), and the intercept is 0.433mm. The 1st to 3rd tool processing forms a large triangular prism. The frustum is formed into a parallelogram unit 1 (i.e., two large triangular frustums form a parallelogram unit 1 with a side length of 500 microns), that is, the side length of the parallelogram unit 1 can also be 500 microns. Then, the second tool is used to process the array along the center line of the large triangular frustum. The 4th to 6th tools are used to form a composite microprismatic reflective film composed of a parallelogram unit array. Each parallelogram unit contains 8 three reflecting surfaces with a side length of 250 μm, each of which is composed of three different triangular pyramid microprismatic reflective films composed of two inclination angles.

[0026] In order to verify the significant advantages of the above embodiments of the present application, a comparative example is provided below: The comparative tool has a blade angle α of 70.50 degrees, a triangular pyramid side length of 250 μm, and a B-axis rotation angle of 0 degrees (or 180 degrees), 60 degrees (or 240 degrees), and 120 degrees (or 300 degrees). The intercept is 216.5 μm. The array is processed to form a conventional triangular pyramid microprismatic reflective film composed of an array of identical parallelogram units, and each parallelogram unit is composed of two identical triangular pyramids.

[0027] Comparison of retroreflective performance test data of 2 samples:

[0028] Technical Advantages: The comparative example is a conventional triangular pyramid microprismatic reflective sheeting, whose retroreflective performance is mainly distributed at a small observation angle of 0.2 degrees. It cannot meet the requirements of the Class V standard under the test conditions of an incident angle of 30 degrees, an observation angle of 0.5 degrees and 1 degree, and an observation angle of 1 degree, an incident angle of -4 degrees and 15 degrees. The microprismatic reflective sheeting prepared by the present invention is composed of three different triangular pyramids, which optimizes and improves the retroreflective performance under large observation angle and large incident angle test conditions, so that the retroreflective performance under all test conditions meets the Class V standard requirements.

[0029] The mold obtained by the above processing is then processed by conventional technical means to obtain a reflective film (which is existing technology and will not be described here).

[0030] In addition, performance testing can be performed on samples (or reflective film samples) produced by using different cutting tools and processing methods to verify and compare the performance of the mold or reflective film obtained by the technical solution of this application.

[0031] The specific different tools and processing methods are as follows: ① Using first tools with tool angles α, respectively, to independently process microprismatic reflective film samples with triangular pyramid unit structures having pyramid surface inclination angles of α / 2 and to test them.

[0032] ② Use the third type of tool with a tool angle of γ=2*β-α to independently process microprismatic reflective film samples with a triangular pyramid unit structure with a pyramid surface inclination angle of β-α / 2 and test them.

[0033] ③ Use the first tool with a tool angle of α to process the two pyramidal surfaces of the triangular pyramid, and then use the third tool with a tool angle of γ to process the third pyramidal surface of the triangular pyramid. In this way, a "mixed" triangular pyramid reflective film sample is formed and tested.

[0034] In the three triangular pyramid reflective sheeting samples obtained by the above three processing methods, the bottom surface shape and size of each triangular pyramid unit are consistent with those of the single triangular pyramid in the present application. The difference lies in the difference in the angle pyramid surfaces. The three triangular pyramid reflective sheeting samples obtained by the three processing methods have a single optical design variable, and it is difficult to obtain different incident angles and observation angles (especially wide angles). The performance is lower than or close to that of Class IV reflective sheeting.

[0035] Furthermore, the "Method for Manufacturing Microprismatic Reflective Sheeting with a Double Triangular Pyramid Combination Structure and Its Mold" (Publication No. CN118759624B) uses a first tool with a knife angle α to machine the large triangular pyramid, and then uses a second tool with a knife angle β to machine the large triangular pyramid (a total of six cuts). Although adjusting the angle variables of the triangular pyramid at the center can optimize the wide-angle performance of the reflective sheeting to a certain extent, or achieve a certain degree of optimization of the 0-degree and 90-degree performance of the reflective sheeting, under the same processing steps (this application also processes six cuts), the microprismatic reflective sheeting produced by this patent only has the design freedom of two triangular pyramids, and also has the disadvantage of insufficient freedom of optical design optimization.

[0036] The present application has three triangular pyramids, namely, a triangular pyramid A with a pyramidal surface inclination angle of α / 2, a triangular pyramid B with a pyramidal surface inclination angle of β-α / 2, and a "mixed" triangular pyramid C with three pyramidal surface inclination angles of α / 2, α / 2 and β-α / 2 respectively; it achieves the design freedom of the three triangular pyramids, and the area proportions of the three triangular pyramids A, triangular pyramid B and triangular pyramid C are 50%, 12.5% and 37.5% respectively, which can further reasonably optimize the performance under different application conditions, thereby obtaining wide-angle performance improvement that cannot be achieved by the micro-prismatic reflective film of the traditional triangular pyramid unit structure and the double triangular pyramid combination structure, as well as optimization and balance of the overall comprehensive performance.

[0037] In summary, the present invention has the following technical advantages.

[0038] From an optical design perspective, increased optical design freedom means that optical systems can simultaneously meet performance indicators for a wider range of different application conditions. For high-performance Class V reflective sheeting, improving its wide-angle performance at large observation angles and large incident angles, as well as its performance at 90-degree and 0-degree azimuth orientations, and optimizing and balancing these performances have always been the focus of research and development in Class V reflective sheeting technology. The reflective sheeting of the present invention comprises three triangular pyramids: a triangular pyramid A with a pyramidal surface inclination angle of α / 2, a triangular pyramid B with a pyramidal surface inclination angle of β-α / 2, and a "hybrid" triangular pyramid C with three pyramidal surface inclination angles of α / 2, α / 2, and β-α / 2, respectively. This achieves design freedom for the three triangular pyramids, with the area proportions of the three triangular pyramids A, B, and C being 50%, 12.5%, and 37.5%, respectively. This allows for optimal performance optimization for different application conditions, thereby achieving wide-angle performance improvements unattainable with conventional microprismatic reflective sheeting with triangular pyramid unit structures or dual triangular pyramid combination structures, as well as optimizing and balancing overall comprehensive performance.

[0039] In addition, the second tool used in the present invention is a β tool, and its deflection angle is selected as △ = α / 2-β / 2 (i.e., the symmetry center plane of the second tool and the normal plane of the mold substrate form a deflection angle △), so as to obtain a typical reflective film with a combination structure of three triangular pyramids; The mold manufacturing of the reflective film of the present invention is equivalent to using a second tool with an asymmetric structure design to process and form the film. The tool angle is γ=α / 2+(β-α / 2). One side of the mechanical center axis is α / 2, and the other side is β-α / 2. In fact, it is equivalent to using a tool with a tool angle of β plus a deflection angle △=α / 2-β / 2 to process and form the film. By selecting different deflection angle values △ but not zero, it is expected to obtain a micro-prismatic reflective film design composed of three different triangular pyramids (with varying inclination angles of the pyramidal surfaces), thereby improving the overall performance of the reflective film and optimizing the wide-angle performance, small-angle performance, and 90-degree and 0-degree orientation performance.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention. They should all be included in the scope of the technical solution for protection of the present invention.

Claims

1. A microprismatic reflective sheeting having a combination of three triangular pyramids, characterized by: The surface of the microprismatic reflective film is formed by an array of identical parallelogram units (1), each parallelogram unit (1) is composed of four identical triangular pyramids A, one triangular pyramid B and three identical triangular pyramids C, the orientations of the four triangular pyramids A are 180 degrees to the orientations of the three triangular pyramids C and the triangular pyramid B, and the three triangular pyramids C and the triangular pyramid B are staggered between the four triangular pyramids A; the bottom surfaces of the triangular pyramids B and the triangular pyramid C are identical equilateral triangles, the inclination angles of the three angular pyramid surfaces of each triangular pyramid A are all α / 2, the inclination angles of the angular pyramid surfaces of the triangular pyramid B are all β-α / 2, and the inclination angles of the three angular pyramid surfaces of the triangular pyramid C are α / 2, α / 2 and β-α / 2 respectively.

2. The microprismatic reflective sheeting having a combination of three triangular pyramids according to claim 1, wherein: The triangular pyramids A are triangular pyramid A1, triangular pyramid A2, triangular pyramid A3 and triangular pyramid A4, the triangular pyramids C are triangular pyramid C1, triangular pyramid C2 and triangular pyramid C3, the first row of the parallelogram unit body (1) is triangular pyramid A3, triangular pyramid C1, triangular pyramid A4 and triangular pyramid C2, the second row of the parallelogram unit body (1) is triangular pyramid A1, triangular pyramid B, triangular pyramid A2 and triangular pyramid C3, and the directions of adjacent triangular pyramids are 180 degrees to each other.

3. The microprismatic reflective sheeting having three combinations of triangular pyramids according to claim 2, wherein: The pyramidal surface A101 of the triangular pyramid A1 is coplanar with the pyramidal surface A201 of the triangular pyramid A2, the pyramidal surface C101 of the triangular pyramid C1 is coplanar with the pyramidal surface C201 of the triangular pyramid C2, the pyramidal surface A102 of the triangular pyramid A1 is coplanar with the pyramidal surface A301 of the triangular pyramid A3, the pyramidal surface C301 of the triangular pyramid C3 is coplanar with the pyramidal surface C202 of the triangular pyramid C2, the pyramidal surface A202 of the triangular pyramid A2 is coplanar with the pyramidal surface A302 of the triangular pyramid A3 Coplanar, the pyramidal surface C302 of the triangular pyramid C3 is coplanar with the pyramidal surface C102 of the triangular pyramid C1, the pyramidal surface A303 of the triangular pyramid A3 is coplanar with the pyramidal surface A401 of the triangular pyramid A4, the pyramidal surface B001 of the triangular pyramid B is coplanar with the pyramidal surface C303 of the triangular pyramid C3, the pyramidal surface B002 of the triangular pyramid B is coplanar with the pyramidal surface C103 of the triangular pyramid C1, and the pyramidal surface A203 of the triangular pyramid A2 is coplanar with the pyramidal surface A402 of the triangular pyramid A4.

4. The mold for the microprismatic reflective film having a combination of three triangular pyramids according to claim 3, wherein: The α=70.50 degrees and the β=70.43 degrees.

5. A method for manufacturing a mold for a microprismatic reflective sheeting having a combination of three triangular pyramids, the method being used to manufacture the mold for the microprismatic reflective sheeting having a combination of three triangular pyramids as claimed in any one of claims 1, 2, 3 or 4, characterized in that: The mold base (K1) is horizontally mounted on a workbench (K2). The workbench can drive the mold base to move along the horizontal X-axis and Y-axis, and the B-axis turntable on the workbench can drive the mold base to rotate around the normal B-axis of the mold base. A spindle (K3) and a flying cutter disc (K4) fixedly connected to the spindle are provided above the mold base. A tool (K5) is mounted on the flying cutter disc. The tool can rotate around the Y-axis driven by the spindle. The specific steps during manufacturing are as follows: Step 1: Rotate the mold substrate on the B-axis turntable to 0 degrees, and use the first tool with a tool angle of α installed on the fly cutter head to machine the two side cone surfaces of the parallelogram unit, namely, the cone surface A101 of the triangular pyramid A1, the cone surface A201 of the triangular pyramid A2, the cone surface C101 of the triangular pyramid C1, and the cone surface C201 of the triangular pyramid C2, with an inclination angle of α / 2; Step 2: Rotate the mold substrate on the B-axis turntable to 120 degrees, and use the first tool with a tool angle of α installed on the fly cutter head to machine the other two cone surfaces of the parallelogram unit, namely, the cone surface A102 of the triangular pyramid A1, the cone surface A301 of the triangular pyramid A3, the cone surface C301 of the triangular pyramid C3, and the cone surface C202 of the triangular pyramid C2, whose inclination angles are also α / 2; Step 3: Rotate the mold base material on the B-axis turntable to 240 degrees, and use the first tool with a tool angle of α installed on the fly cutter disc to machine the two diagonal cone surfaces of the parallelogram unit (1), namely, the cone surface A202 of the triangular pyramid A2, the cone surface A302 of the triangular pyramid A3, the cone surface C302 of the triangular pyramid C3, and the cone surface C102 of the triangular pyramid C1, whose inclination angle is also α / 2; Step 4: Replace the second tool with a cutting angle of β on the cutter disc, and adjust the tool to produce a deflection angle △, that is, the symmetry center plane of the second tool forms a deflection angle △ with the normal plane of the mold substrate, and △ is not zero, so that the inclination angle of the blade on one side of the tool angle is β / 2+△=α / 2, and the inclination angle of the blade on the other side is β / 2-△=β-β / 2-△=β-(β / 2+△)=β-α / 2; based on the structure processed in step 3, rotate the mold substrate to the 0 degree position, and then use the adjusted second tool to process and form the pyramid surface B001 of triangular pyramid B and the pyramid surface C303 of triangular pyramid C3, whose inclination angle is β-α / 2; at the same time, form the pyramid surface A303 of triangular pyramid A3 and the pyramid surface A401 of triangular pyramid A4, whose inclination angle is α / 2; Step 5: Rotate the mold substrate 120 degrees and use the adjusted second tool to machine the pyramidal surface B002 of triangular pyramid B and the pyramidal surface C103 of triangular pyramid C1, with an inclination angle of β-α / 2. Simultaneously, machine the pyramidal surface A203 of triangular pyramid A2 and the pyramidal surface A402 of triangular pyramid A4, with an inclination angle of α / 2. Step 6: Rotate the mold substrate to 240 degrees again, and use the adjusted second tool to machine the pyramidal surface B003 of triangular pyramid B and the pyramidal surface C203 of triangular pyramid C2, with an inclination angle of β-α / 2. Simultaneously, machine the pyramidal surface A103 of triangular pyramid A1 and the pyramidal surface A403 of triangular pyramid A4, with an inclination angle of α / 2. At this point, the mold for the microprismatic reflective film composed of three different triangular pyramid structures, namely, triangular pyramid A with an inclination angle of α / 2, triangular pyramid B with an inclination angle of β-α / 2, and triangular pyramid C with inclination angles of α / 2, α / 2, and β-α / 2, has been processed and formed.

6. The method for manufacturing a mold for a microprismatic reflective film using a combination of three triangular pyramid structures according to claim 5, characterized in that: The first type of tool has a tool angle of α=70.50 degrees; the second type of tool is a symmetrical tool with β=70.43 degrees. By adjusting the tool deflection angle △=0.035 degrees, the tool has an inclination angle of 35.25 degrees on one side and 35.18 degrees on the other side. During processing, the α tool is first used, and the B-axis rotation angles are 0 degrees, 60 degrees, and 120 degrees respectively, and array processing is performed with an intercept of 0.433mm. The 1st to 3rd cuts form a large triangular pyramid with a side length of 500 microns. Then, the second type of tool is used to form an array along the center line of the large triangular pyramid. The 4th to 6th cuts form a composite micro-prismatic reflective film composed of a parallelogram unit array. Each parallelogram unit contains 8 reflective surfaces with a side length of 250μm, each of which is composed of three different triangular pyramid micro-prismatic reflective films composed of two inclination angles.

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