Microprism reflective film integrated with four triangular pyramid structures and manufacturing method of mold of microprism reflective film

Abstract

The invention relates to a microprism reflective film integrating four triangular pyramid structures and a manufacturing method of a mold of the microprism reflective film, the surface of the microprism reflective film is formed by the same parallelogram unit array, and each parallelogram unit is composed of three same triangular pyramids A, one triangular pyramid B1, three same triangular pyramids C and one triangular pyramid D1, the inclination angles of the three pyramid surfaces of each triangular pyramid A are alpha / 2, alpha / 2 and beta / 2 +, the inclination angle of the pyramid surface of each triangular pyramid B1 is beta / 2-, the inclination angles of the three pyramid surfaces of each triangular pyramid C are alpha / 2, alpha / 2 and beta / 2-, and the inclination angle of the pyramid surface of each triangular pyramid D1 is beta / 2 +; according to the microprism reflective film integrating the four triangular pyramid structures and the manufacturing method of the mold thereof, the design is reasonable, the degree of freedom of optical design can be further increased, and the retroreflection performance can be optimized.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a microprism reflective film integrating four triangular pyramidal structures and its mold. Background Technology

[0002] Using a single tool to machine the three pyramidal faces of a triangular pyramid without any deviation is an internationally accepted standard design for microprism reflective films based on a triangular pyramid structure. The inclination angle of each of the three pyramidal faces is α / 2. Figure 1 As shown, this design has a simple structure and is not complicated to manufacture. The retroreflected light spot intensity is distributed in a narrow observation angle range, which can meet the performance requirements of Class IV reflective film in the national standard.

[0003] The patent "A Novel Method for Manufacturing a Microprism-Type Reflective Material Mold" (Patent No. 201410387342.3, hereinafter referred to as Prior Art 1) proposes a method for manufacturing a multi-triangular pyramid structure microprism reflective film mold using one tool with six cuts. The tool used is an asymmetrical tool with cutting angles A and B on the left and right sides respectively. During processing, the B-axis rotation angles of the 1st and 4th cuts, the 2nd and 5th cuts, and the 3rd and 6th cuts are 180° to each other. The reflective film mold consists of a triangular pyramid A with a facet angle of 'a' and an area percentage of 12.5%; a triangular pyramid B with three facet angles of 'b' and an area percentage of 12.5%; a "composite cone" triangular pyramid C with three facet angles of 'a', 'a', and 'b' and an area percentage of 37.5%; and a "composite cone" triangular pyramid D with three facet angles of 'a', 'b', and 'b' and an area percentage of 37.5%. Figure 2 As shown.

[0004] The shortcomings of the above technology are as follows: the retroreflected rays after the incident light is reflected by the triangular pyramid unit are distributed in 6 directions to form 6 light spots. The distribution positions of the 6 light spots are different for each different design of the triangular pyramid, which makes the retroreflection performance distribution of the triangular pyramid have obvious directionality. At the same time, the light intensity distribution characteristics of each light spot are caused by the divergence angle of the light source and the processing deviation of the tool and mold, which can only form a similar normal distribution within a narrow observation angle range. This makes it impossible for a single triangular pyramid to simultaneously meet the performance requirements of Class V reflective film under different observation conditions.

[0005] As is well known, from an optical design perspective, increased freedom in optical design means that optical systems can potentially meet more performance indicators for different application conditions simultaneously. The trend in the microprism reflective film industry is to design and fabricate microprism reflective films with more optical freedom on a single mold substrate, improving their wide-angle performance (large observation angle, large incident angle) and optimizing and balancing performance in different orientations to meet the requirements of Class V reflective film technical standards. The patent "A Novel Method for Manufacturing a Microprism-Type Reflective Material Mold" (…) Although the method of patent number 201410387342.3 forms similar four triangular pyramid structures, it only has two optical degrees of freedom (cutting angles). The distribution of the observation angles corresponding to the centers of the four triangular pyramid light spots is as follows: triangular pyramid A (accounting for 1 / 8), triangular pyramid C (accounting for 3 / 8), triangular pyramid D (accounting for 3 / 8), and triangular pyramid B (accounting for 1 / 8). Moreover, the observation angles corresponding to the centers of the retroreflection light spots of triangular pyramids C and D are restricted by triangular pyramids A and B. This has the disadvantage of insufficient degrees of freedom for optical design optimization, which limits further optimization of the retroreflection performance distribution. Summary of the Invention

[0006] In view of the above-mentioned problems, the purpose of this invention is to propose a manufacturing method for a microprism reflective film integrating four triangular pyramid structures and its mold. This manufacturing method for a microprism reflective film integrating four triangular pyramid structures and its mold is reasonably designed, which can further increase the degree of freedom of optical design and is beneficial to optimizing retroreflection performance.

[0007] The technical solution of the present invention is as follows:

[0008] This invention integrates a microprism reflective film with four combinations of triangular pyramids. The surface of the microprism reflective film is formed by an array of identical parallelogram units. Each parallelogram unit consists of three identical triangular pyramids A, one triangular pyramid B1, three identical triangular pyramids C, and one triangular pyramid D1. The three identical triangular pyramids A are pyramids A1, A2, and A3, and the three identical triangular pyramids C are pyramids C1, C2, and C3. The bases of the three identical triangular pyramids A, B1, C, and D1 are all... In the same equilateral triangle, the inclination angles of the three corner faces of each triangular pyramid A are α / 2, α / 2, β / 2+△, the inclination angle of the corner face of triangular pyramid B1 is β / 2-△, the inclination angles of the three corner faces of each triangular pyramid C are α / 2, α / 2, and β / 2-△, and the inclination angle of the corner face of triangular pyramid D1 is β / 2+△. The first row of the parallelogram unit is arranged in order as triangular pyramid A3, triangular pyramid C1, triangular pyramid D1, and triangular pyramid C2, and the second row of the parallelogram unit is arranged in order as triangular pyramid A1, triangular pyramid B1, triangular pyramid A2, and triangular pyramid C3. The orientations of adjacent triangular pyramids are 180 degrees to each other.

[0009] Preferably, the pyramidal face A101 of the triangular pyramid A1 is coplanar with the pyramidal face A201 of the triangular pyramid A2; the pyramidal face C101 of the triangular pyramid C1 is coplanar with the pyramidal face C201 of the triangular pyramid C2; the pyramidal face A102 of the triangular pyramid A1 is coplanar with the pyramidal face A301 of the triangular pyramid A3; the pyramidal face C301 of the triangular pyramid C3 is coplanar with the pyramidal face C202 of the triangular pyramid C2; and the pyramidal face A202 of the triangular pyramid A2 is coplanar with the pyramidal face A301 of the triangular pyramid A3. 2. The pyramidal faces C302 of triangular pyramid C3 and C102 of triangular pyramid C1 are coplanar. The pyramidal faces A303 of triangular pyramid A3 and D101 of triangular pyramid D1 are coplanar. The pyramidal faces B101 of triangular pyramid B1 and C303 of triangular pyramid C3 are coplanar. The pyramidal faces B102 of triangular pyramid B1 and C103 of triangular pyramid C1 are coplanar. The pyramidal faces A203 of triangular pyramid A2 and D102 of triangular pyramid D1 are coplanar.

[0010] Preferably, the base areas of the aforementioned triangular pyramids A, B1, C, and D1 account for 37.5%, 12.5%, 37.5%, and 12.5%, respectively.

[0011] Preferably, the above α = 70.30-70.80 degrees, β = 70.35-70.75 degrees, and Δ = < 0.2 degrees.

[0012] Preferably, the above α=70.50 degrees, β=70.72 degrees, Δ=0.05 degrees; the tilt angles of the three reflecting surfaces of the triangular pyramid A with an area of ​​3 / 8 are 35.25 degrees, 35.25 degrees and 35.41 degrees respectively; the tilt angles of the three reflecting surfaces of the triangular pyramid B1 with an area of ​​1 / 8 are all 35.31 degrees; the tilt angles of the three reflecting surfaces of the triangular pyramid C with an area of ​​3 / 8 are 35.25 degrees, 35.25 degrees and 35.31 degrees respectively; and the tilt angles of the three reflecting surfaces of the triangular pyramid D1 with an area of ​​1 / 8 are all 35.41 degrees.

[0013] Preferably, the side length of the base of each triangular pyramid is 235 micrometers, and the height of the triangular pyramid is approximately 96 micrometers.

[0014] This invention discloses a method for manufacturing a mold for a microprism reflective film integrating four types of triangular pyramid combinations, used to manufacture the aforementioned mold for a microprism reflective film integrating four types of triangular pyramid combinations, characterized in that:

[0015] The mold substrate is horizontally mounted on a worktable. The worktable can move the mold substrate along the horizontal X and Y axes, and the B-axis rotary table on the worktable can rotate the mold substrate around the normal B-axis. Above the mold substrate is a spindle parallel to the upper surface of the mold substrate and a fly cutter head fixedly connected to the spindle. The fly cutter head is equipped with a cutting tool, which can rotate around the Y-axis under the drive of the spindle. The specific manufacturing steps are as follows:

[0016] Step 1: Rotate the mold base material on the B-axis turntable to 0 degrees. Use the first type of tool with a tool angle of α mounted on the fly cutter head to machine the two conical surfaces of the parallelogram unit, namely the corner surface A101 of triangular pyramid A1, the corner surface A201 of triangular pyramid A2, the corner surface C101 of triangular pyramid C1, and the corner surface C201 of triangular pyramid C2. The inclination angle is α / 2. The first type of tool is a symmetrical tool with the same inclination angle on both sides.

[0017] Step 2: Rotate the mold base material on the B-axis turntable to 120 degrees, and use the first type of tool with a tool angle of α mounted on the fly cutter head to machine the other two conical surfaces of the parallelogram unit, namely the corner surface A102 of the triangular pyramid A1, the corner surface A301 of the triangular pyramid A3, the corner surface C301 of the triangular pyramid C3, and the corner surface C202 of the triangular pyramid C2, with an inclination angle of α / 2.

[0018] Step 3: Rotate the mold substrate on the B-axis turntable to 60 degrees, and use the first type of tool with a tool angle of α mounted on the fly cutter head to machine the two opposite corner cones of the parallelogram unit, that is, 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, with an inclination angle of α / 2.

[0019] Step 4: Replace and install the second type of symmetrical cutting tool with a cutting angle of β on the flying cutter head. Adjust the tool to create an angle △, so that the inclination angle of the cutting edge on one side is β / 2-△ and the inclination angle of the cutting edge on the other side is β / 2+△. Based on the structure processed in Step 3, rotate the mold base material to the 0-degree position and use the second type of cutting tool to process and form the pyramidal surface B101 of triangular pyramid B1 and the pyramidal surface C303 of triangular pyramid C3, with an inclination angle of β / 2-△; at the same time, form the pyramidal surface A303 of triangular pyramid A3 and the pyramidal surface D101 of triangular pyramid D1, with an inclination angle of β / 2+△.

[0020] Step 5: Rotate the mold base material in sequence to 120 degrees, and use the second type of tool to process and form the pyramidal surface B102 of the triangular pyramid B1 and the pyramidal surface C103 of the triangular pyramid C1, with an inclination angle of β / 2-△. At the same time, form the pyramidal surface A203 of the triangular pyramid A2 and the pyramidal surface D102 of the triangular pyramid D1, with an inclination angle of β / 2+△.

[0021] Step 6: Rotate the mold base material to 60 degrees in sequence, and use the second type of tool to process and form the pyramidal surface B103 of triangular pyramid B1 and the pyramidal surface C203 of triangular pyramid C2, with an inclination angle of β / 2-△; at the same time, form the pyramidal surface A103 of triangular pyramid A1 and the pyramidal surface D103 of triangular pyramid D1, with an inclination angle of β / 2+△.

[0022] At this point, the mold for the microprism reflective film, composed of four different triangular pyramid structures—A with tilt angles of α / 2, α / 2, and β / 2+△; B1 with tilt angle of β / 2-△; C with tilt angles of α / 2, α / 2, and β / 2-△; and D1 with tilt angle of β / 2+△—has been processed and formed.

[0023] Preferably, the first type of tool has a cutting angle α = 70.50 degrees; the second type of tool is a symmetrical tool with a cutting angle β = 70.72 degrees. During machining, the first type of tool is used first, and machining is performed in an array with B-axis rotation angles of 0 degrees, 60 degrees, and 120 degrees, and an intercept pitch of 0.407 mm. The first three cuts form a large triangular pyramid. Then, the second type of tool is switched, and machining is performed in an array along the center line connecting the edges of the large triangular pyramid with B-axis rotation angles of 0 degrees, 120 degrees, and 60 degrees, and an intercept pitch of 0.407 mm. The resulting shape consists of parallelogram units. The composite microprism reflective film, composed of an array, has eight triangular pyramids with a side length of 235 micrometers in each parallelogram unit. Specifically, the three reflective surfaces of pyramid A (3 / 8 area) have tilt angles of 35.25°, 35.25°, and 35.41°; the three reflective surfaces of pyramid B (1 / 8 area) all have a tilt angle of 35.31°; the three reflective surfaces of pyramid C (3 / 8 area) have tilt angles of 35.25°, 35.25°, and 35.31°; and the three reflective surfaces of pyramid D (1 / 8 area) all have a tilt angle of 35.41°.

[0024] The present invention has the following technical advantages:

[0025] The new reflective film design of this invention consists of four different triangular pyramid structures with area proportions of 3 / 8, 1 / 8, 3 / 8, and 1 / 8, respectively. Each of the four pyramids possesses a different optical structure, and the tilt angles of its three reflective cone surfaces can be formed by combining three different cutting angles. This increases the degree of freedom in the optical design of the pyramids. By adjusting the cutting angle design value of the first cutter, the observation angle of the light spot center of pyramids A and C (each with an area proportion of 3 / 8) can be changed, increasing the optical design freedom of the reflective film and preventing it from being limited to the observation angles corresponding to the retroreflected light spot centers formed by pyramids B1 and D1. This further optimizes the performance distribution of the reflective film while maintaining a simple structure and effectively controlling the manufacturing complexity of the reflective film mold. It also facilitates the balance between small-angle and wide-angle performance of the reflective film, as well as the balance of performance across different orientations. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings;

[0027] Figure 1 This is the front view of a traditional triangular pyramid;

[0028] Figure 2 This is the front view of an existing triangular pyramid;

[0029] Figure 3 This is a front view of the microprism reflective film of this application;

[0030] Figure 4 This is a three-dimensional schematic diagram of the mold substrate being processed on a workbench;

[0031] Figure 5 This is a schematic diagram of the cross-sectional structure of the die substrate for the flying knife machining process;

[0032] Figure 6 This is a three-dimensional structural schematic diagram of the finished mold of the microprism reflective film of the present invention;

[0033] Figure 7 yes Figure 6 Main view (for clarity, some labels in the diagram correspond one-to-one) Figure 3 (The label of the reflective film).

[0034] Figure 8 This is a schematic diagram of the three-dimensional structure of the mold base material before processing;

[0035] Figure 9 yes Figure 8 The main view;

[0036] Figure 10 yes Figure 8 The main view of the mold substrate after processing in step 1;

[0037] Figure 11 yes Figure 10 The main view of the mold substrate after processing in step 2;

[0038] Figure 12 yes Figure 11 The main view of the mold substrate after processing in step 3;

[0039] Figure 13 yes Figure 12 A three-dimensional image;

[0040] Figure 14 yes Figure 12 The main view of the mold substrate after processing in step 4;

[0041] Figure 15 yes Figure 14 A schematic diagram of the three-dimensional structure;

[0042] Figure 16 yes Figure 14 The main view of the mold substrate after processing in step 5;

[0043] Figure 17 yes Figure 16A schematic diagram of the three-dimensional structure;

[0044] Figure 18 yes Figure 16 The main view of the mold substrate after processing in step 6;

[0045] Figure 19 yes Figure 18 A three-dimensional structural diagram (i.e., a three-dimensional structural diagram of the finished mold of this application). Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0047] The microprism reflective film of this invention, which integrates four combinations of triangular pyramids, has a surface formed by an array of identical parallelogram unit cells 1. Each parallelogram unit cell 1 consists of three identical triangular pyramids A, one triangular pyramid B1, three identical triangular pyramids C, and one triangular pyramid D1. The three identical triangular pyramids A are triangular pyramid A1, triangular pyramid A2, and triangular pyramid A3, and the three identical triangular pyramids C are triangular pyramid C1, triangular pyramid C2, and triangular pyramid C3. The bases of the three identical triangular pyramids A, B1, C, and D1 are all identical equilateral triangles. The inclination angles of the three corner faces of each triangular pyramid A are α / 2, α / 2, and β / 2+△, the inclination angle of the corner face of triangular pyramid B1 is β / 2-△, the inclination angles of the three corner faces of each triangular pyramid C are α / 2, α / 2, and β / 2-△, and the inclination angle of the corner face of triangular pyramid D1 is β / 2+△. The first row of parallelogram unit 1 is arranged in order as triangular pyramid A3, triangular pyramid C1, triangular pyramid D1, and triangular pyramid C2, and the second row of parallelogram unit 1 is arranged in order as triangular pyramid A1, triangular pyramid B1, triangular pyramid A2, and triangular pyramid C3. The orientations of adjacent triangular pyramids are 180 degrees to each other.

[0048] The pyramidal face A101 of the aforementioned triangular pyramid A1 is coplanar with the pyramidal face A201 of the triangular pyramid A2; the pyramidal face C101 of the triangular pyramid C1 is coplanar with the pyramidal face C201 of the triangular pyramid C2; the pyramidal face A102 of the triangular pyramid A1 is coplanar with the pyramidal face A301 of the triangular pyramid A3; the pyramidal face C301 of the triangular pyramid C3 is coplanar with the pyramidal face C202 of the triangular pyramid C2; and the pyramidal face A202 of the triangular pyramid A2 is coplanar with the pyramidal face A302 of the triangular pyramid A3. The pyramidal faces C302 of triangular pyramid C3 and C102 of triangular pyramid C1 are coplanar; the pyramidal face A303 of triangular pyramid A3 and D101 of triangular pyramid D1 are coplanar; the pyramidal face B101 of triangular pyramid B1 and C303 of triangular pyramid C3 are coplanar; the pyramidal face B102 of triangular pyramid B1 and C103 of triangular pyramid C1 are coplanar; and the pyramidal face A203 of triangular pyramid A2 and D102 of triangular pyramid D1 are coplanar.

[0049] The base areas of triangular pyramids A, B1, C, and D1 account for 37.5%, 12.5%, 37.5%, and 12.5%, respectively.

[0050] Where α = 70.30-70.80 degrees, β = 70.35-70.75 degrees, and Δ = < 0.2 degrees.

[0051] One embodiment is as follows: α = 70.50 degrees, β = 70.72 degrees, Δ = 0.05 degrees; the three reflecting surfaces of triangular pyramid A, which accounts for 3 / 8 of the area, have tilt angles of 35.25 degrees, 35.25 degrees, and 35.41 degrees, respectively; the three reflecting surfaces of triangular pyramid B1, which accounts for 1 / 8 of the area, all have tilt angles of 35.31 degrees; the three reflecting surfaces of triangular pyramid C, which accounts for 3 / 8 of the area, all have tilt angles of 35.25 degrees, 35.25 degrees, and 35.31 degrees, respectively; and the three reflecting surfaces of triangular pyramid D1, which accounts for 1 / 8 of the area, all have tilt angles of 35.41 degrees; the side length of the base of each triangular pyramid is 235 micrometers, and the height of the triangular pyramid is approximately 96 micrometers.

[0052] The specific processing method for the mold used to manufacture the aforementioned microprism reflective film integrating four triangular pyramid combinations is as follows.

[0053] Example 1, as Figure 4 , 5 As shown, the mold substrate K1 is horizontally mounted on the worktable. The worktable can move the mold substrate along the horizontal X and Y axes, and the B-axis rotary table K2 on the worktable can rotate the mold substrate around the normal B-axis of the mold substrate. Above the mold substrate is a spindle K3 parallel to the upper surface of the mold substrate and a fly cutter head K4 fixedly connected to the spindle. The spindle K3 can be driven by existing machine tool equipment. A cutting tool K5 is mounted on the fly cutter head, and the cutting tool can rotate around the Y-axis under the drive of the spindle. The specific manufacturing steps are as follows:

[0054] Step 1: Rotate the mold substrate on the B-axis turntable to 0 degrees (or 180 degrees) (i.e.) Figure 9 (as shown in the diagram), using the first type of tool with a tool angle of α mounted on the fly cutter head to machine the two conical surfaces of the parallelogram unit (i.e., ... Figure 10 The upper and lower conical surfaces (during processing, the worktable drives the mold substrate to move along the X-axis), namely, the pyramidal surface A101 of triangular pyramid A1, the pyramidal surface A201 of triangular pyramid A2, the pyramidal surface C101 of triangular pyramid C1, and the pyramidal surface C201 of triangular pyramid C2, with an inclination angle of α / 2. The first type of tool is a symmetrical tool with the same inclination angle on both sides. In one embodiment, α = 70.50 degrees, and the inclination angle on both sides is 35.25 degrees. Figure 10 As shown.

[0055] Step 2: Rotate the mold substrate on the B-axis turntable to 120 degrees (or 300 degrees) (i.e., to... Figure 9 Rotate 120 degrees (or 300 degrees) counterclockwise around the center in the state shown, and use the first type of tool with a tool angle of α mounted on the fly cutter head to machine the other two conical surfaces of the parallelogram unit (i.e., Figure 11 The left and right conical surfaces (during processing, the worktable drives the mold substrate to move along the X-axis), namely the pyramidal surface A102 of triangular pyramid A1, the pyramidal surface A301 of triangular pyramid A3, the pyramidal surface C301 of triangular pyramid C3, and the pyramidal surface C202 of triangular pyramid C2, whose inclination angle is also α / 2, such as Figure 11 As shown.

[0056] Step 3: Rotate the mold substrate on the B-axis turntable to 60 degrees (or 240 degrees). Figure 9 In the indicated state, rotate counterclockwise by 60 degrees (or 240 degrees) around the center, and use the first type of tool with a tool angle of α mounted on the fly cutter head to machine the two opposite corner cone surfaces of parallelogram unit 1, that is, the cone surface A202 of triangular pyramid A2, the cone surface A302 of triangular pyramid A3, the cone surface C302 of triangular pyramid C3, and the cone surface C102 of triangular pyramid C1, whose inclination angle is also α / 2, as shown. Figure 12 , 13 As shown.

[0057] Step 4: Replace the second type of symmetrical cutting tool with a cutting angle of β on the fly cutter head. Adjust the tool to create an angle △, so that the inclination angle of the cutting edge on one side is β / 2 - △, and the inclination angle of the cutting edge on the other side is β / 2 + △. Based on the structure processed in Step 3, rotate the mold base material to the 0-degree position (i.e., Figure 9 (As shown in the image), use the second type of tool to machine the pyramidal surfaces B101 and C303 of triangular pyramid B1, with an inclination angle of β / 2 - △; simultaneously machine the pyramidal surfaces A303 of triangular pyramid A3 and D101 of triangular pyramid D1, with an inclination angle of β / 2 + △; as shown in the image. Figure 14 , 15 As shown, in one embodiment, β=70.72 degrees, Δ=0.05 degrees, and the tilt angles on both sides are 35.41 degrees and 35.31 degrees.

[0058] Step 5: Rotate the mold base material sequentially to 120 degrees (i.e., at...) Figure 9 Rotate 120 degrees counterclockwise around the center from the position shown. Use the second type of tool to machine the pyramidal surfaces B102 and C103 of triangular pyramid B1, with an inclination angle of β / 2 - Δ. Simultaneously machine the pyramidal surfaces A203 and D102 of triangular pyramid A2 and D1, with an inclination angle of β / 2 + Δ / 2, as shown. Figure 16 , 17 As shown;

[0059] Step 6: Rotate the mold base material in sequence to a position of 60 degrees (i.e., at...) Figure 9 Rotate 60 degrees counterclockwise around the center from the position shown), and use the previously adjusted second type of tool to machine the pyramidal surfaces B103 of triangular pyramid B1 and C203 of triangular pyramid C2, with an inclination angle of β / 2 - △; simultaneously machine the pyramidal surfaces A103 of triangular pyramid A1 and D103 of triangular pyramid D1, with an inclination angle of β / 2 + △; as shown Figure 18 , 19 As shown.

[0060] At this point, the mold for the microprism reflective film, composed of four different triangular pyramid structures—A with tilt angles of α / 2, α / 2, and β / 2+△; B1 with tilt angle of β / 2-△; C with tilt angles of α / 2, α / 2, and β / 2-△; and D1 with tilt angle of β / 2+△—has been processed and formed.

[0061] Figure 18 , 19 That is, a schematic diagram of the structure of the finished mold of this application. Figure 18 , 19 and Figure 7 , 8 They are identical. They are all schematic diagrams of the mold used to manufacture the reflective film of this application. The shape and size of the mold obtained by the above method are the same as the reflective film subsequently manufactured from that mold. For ease of visual comparison, therefore... Figure 7 The various labels and Figure 2 The same numbering is used to reflect the one-to-one correspondence between the mold and the reflective film.

[0062] Specific machining example of Example 1: The first type of tool has a cutting angle α = 70.50 degrees; the second type of tool is a symmetrical tool with a cutting angle β = 70.72 degrees. During machining, the first type of tool is used first, and machining is performed in an array with rotation angles of 0 degrees, 60 degrees, and 120 degrees along the B-axis, with a cutoff distance of 0.407 mm. The first three cuts form a large triangular pyramid. The second type of tool is then used, and the offset angle Δ is adjusted. Next, machining is performed in an array along the center line connecting the edges of the large triangular pyramid with rotation angles of 0 degrees, 120 degrees, and 60 degrees along the B-axis, with a cutoff distance of 0.407 mm. The resulting shape is a parallelogram. The composite microprism reflective film is composed of a unit array. Each parallelogram unit contains eight triangular pyramids with a side length of 235 micrometers. The three reflective surfaces of pyramid A (3 / 8 area) have tilt angles of 35.25°, 35.25°, and 35.41°; the three reflective surfaces of pyramid B (1 / 8 area) all have a tilt angle of 35.31°; the three reflective surfaces of pyramid C (3 / 8 area) all have a tilt angle of 35.25°, 35.25°, and 35.31°; and the three reflective surfaces of pyramid D (1 / 8 area) all have a tilt angle of 35.41°.

[0063] Although the method proposed in prior art 1 also forms four types of triangular pyramid structures, it only has two optical degrees of freedom (cutting angles). The observation angles corresponding to the retroreflection spot centers of triangular pyramids C and D with an area ratio of 3 / 8 are limited to the observation angles corresponding to the retroreflection spot centers of triangular pyramids A and B with an area ratio of 1 / 8. Furthermore, once the observation angles corresponding to the retroreflection spots of triangular pyramids A and B are determined, the observation angles of the retroreflection spot centers of the other two triangular pyramids are also determined. This results in insufficient degrees of freedom for optical design optimization. This limitation restricts further optimization of retroreflective performance distribution. The present invention proposes a method that uses two blades with different blade angles and the second blade's deflection angle Δ can be adjusted to form four types of triangular pyramid combination structures. However, it adds one degree of freedom in the optical design of the triangular pyramids. The observation angle of the retroreflective spot center of the two triangular pyramids with area ratios of 3 / 8 can be adjusted by the newly added degree of freedom in the optical design (the blade angle α of the first blade). This can further optimize the retroreflective performance distribution of the reflective film and achieve a balance between the small-angle and wide-angle performance of the reflective film as well as a balance between different orientation performances.

[0064] .

[0065] The significant features of this application are:

[0066] 1. The reflective film design of this application adopts the second cutting tool for angular forming processing; 3α+3β, β has an angular or asymmetrical cutting tool, and the area ratio of the four triangular pyramids is 37.5%:37.5%:12.5%:12.5%.

[0067] 2. Compared to the previously applied double triangular pyramid and three triangular pyramid microprism structures, the evolution to four triangular pyramid microprism structures adds a new degree of freedom for the optical design of the reflective film. In addition to the cutting angles of the two tools, the β tool deflection angle is also used as a degree of freedom for optical design.

[0068] 3. Although the innovative reflective film of this application has one less degree of optical design freedom than the microprism reflective film integrating five triangular pyramids described in invention patent 2025107027357, it can still meet the performance requirements of Class V reflective film.

[0069] 4. The innovative design of the reflective film in this application is conducive to improving the overall performance of the reflective film and optimizing the retroreflective performance with wide angle (large viewing angle, large incident angle).

[0070] 5. Under the premise of meeting the performance requirements of Class V reflective film, it is beneficial to reduce the side length and height of the microprism, thereby improving the hot pressing production efficiency of microprism reflective film. The side length of the base of each triangular pyramid can be changed from 250 micrometers to 235 micrometers, and the height of the triangular pyramid can be changed from 102 micrometers to 96 micrometers. Under the premise of ensuring performance, the hot pressing speed of the original reflective film is increased by ≥20%.

[0071] Compared with the 250µm side length of the triangular pyramidal reflective film, the retroreflective performance of the PC hot-pressed reflective film with a side length of 235µm is comparable at both 0-degree and 180-degree orientations, both meeting the requirement of being 1.8 times higher than the national standard value. However, the 235µm side length reflective film has a thickness of only 96µm, which is 6µm thinner than the 102µm thickness of the 250µm side length reflective film. This increases the hot-pressing speed of the original reflective film by ≥20%, thereby improving production efficiency. With the same investment in production equipment, the production cost of the reflective film is reduced.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A microprism reflective film integrating four types of triangular pyramids, characterized in that: The surface of the microprism reflective film is formed by an array of identical parallelogram unit cells (1). Each parallelogram unit cell (1) consists of three identical triangular pyramids A, one triangular pyramid B1, three identical triangular pyramids C, and one triangular pyramid D1. The three identical triangular pyramids A are triangular pyramids A1, A2, and A3, and the three identical triangular pyramids C are triangular pyramids C1, C2, and C3. The bases of the three identical triangular pyramids A, B1, C, and D1 are all identical equilateral triangles. The inclination angles of the three pyramidal faces are all α / 2, α / 2, β / 2+△, the inclination angle of the pyramidal face of triangular pyramid B1 is β / 2-△, the inclination angles of the three pyramidal faces of each triangular pyramid C are α / 2, α / 2 and β / 2-△ respectively, and the inclination angle of the pyramidal face of triangular pyramid D1 is β / 2+△; the first row of the parallelogram unit (1) is arranged in order as triangular pyramid A3, triangular pyramid C1, triangular pyramid D1 and triangular pyramid C2, and the second row of the parallelogram unit (1) is arranged in order as triangular pyramid A1, triangular pyramid B1, triangular pyramid A2 and triangular pyramid C3, and the orientations of adjacent triangular pyramids are 180 degrees to each other.

2. The microprism reflective film integrating four triangular pyramid combinations according to claim 1, characterized in that: The pyramidal face A101 of the triangular pyramid A1 is coplanar with the pyramidal face A201 of the triangular pyramid A2; the pyramidal face C101 of the triangular pyramid C1 is coplanar with the pyramidal face C201 of the triangular pyramid C2; the pyramidal face A102 of the triangular pyramid A1 is coplanar with the pyramidal face A301 of the triangular pyramid A3; the pyramidal face C301 of the triangular pyramid C3 is coplanar with the pyramidal face C202 of the triangular pyramid C2; and the pyramidal face A202 of the triangular pyramid A2 is coplanar with the pyramidal face A302 of the triangular pyramid A3. The pyramidal faces C302 of triangular pyramid C3 and C102 of triangular pyramid C1 are coplanar; the pyramidal face A303 of triangular pyramid A3 and D101 of triangular pyramid D1 are coplanar; the pyramidal face B101 of triangular pyramid B1 and C303 of triangular pyramid C3 are coplanar; the pyramidal face B102 of triangular pyramid B1 and C103 of triangular pyramid C1 are coplanar; and the pyramidal face A203 of triangular pyramid A2 and D102 of triangular pyramid D1 are coplanar.

3. The microprism reflective film integrating four triangular pyramid combinations according to claim 2, characterized in that: The base areas of the three pyramids A, B1, C, and D1 account for 37.5%, 12.5%, 37.5%, and 12.5%, respectively.

4. The microprism reflective film integrating four triangular pyramid combinations according to claim 3, characterized in that: The values ​​are α = 70.30-70.80 degrees, β = 70.35-70.75 degrees, and Δ = < 0.2 degrees.

5. The microprism reflective film integrating four triangular pyramid combinations according to claim 3, characterized in that: The values ​​are α = 70.50 degrees, β = 70.72 degrees, and Δ = 0.05 degrees. The inclination angles of the three reflecting surfaces of the triangular pyramid A (3 / 8 area) are 35.25 degrees, 35.25 degrees, and 35.41 degrees, respectively; the inclination angles of the three reflecting surfaces of the triangular pyramid B1 (1 / 8 area) are all 35.31 degrees; the inclination angles of the three reflecting surfaces of the triangular pyramid C (3 / 8 area) are all 35.25 degrees, 35.25 degrees, and 35.31 degrees, respectively; and the inclination angles of the three reflecting surfaces of the triangular pyramid D1 (1 / 8 area) are all 35.41 degrees.

6. The microprism reflective film integrating four triangular pyramid combinations according to claim 4 or 5, characterized in that: Each triangular pyramid has a base side length of 235 micrometers and a height of approximately 96 micrometers.

7. A method for manufacturing a mold for a microprism reflective film integrating four triangular pyramid combinations, used to manufacture a mold for a microprism reflective film integrating four triangular pyramid combinations as described in any one of claims 1-6, characterized in that: The mold substrate (K1) is horizontally mounted on the worktable. The worktable can move the mold substrate along the horizontal X and Y axes, and the B-axis rotary table (K2) on the worktable can rotate the mold substrate around the normal B-axis of the mold substrate. Above the mold substrate is a spindle (K3) parallel to the upper surface of the mold substrate and a fly cutter head (K4) fixedly connected to the spindle. A cutting tool (K5) is mounted on the fly cutter head. The cutting tool can rotate around the Y-axis under the drive of the spindle. The specific manufacturing steps are as follows: Step 1: Rotate the mold base material on the B-axis turntable to 0 degrees. Use the first type of tool with a tool angle of α mounted on the fly cutter head to machine the two conical surfaces of the parallelogram unit, namely the corner surface A101 of triangular pyramid A1, the corner surface A201 of triangular pyramid A2, the corner surface C101 of triangular pyramid C1, and the corner surface C201 of triangular pyramid C2. The inclination angle is α / 2. The first type of tool is a symmetrical tool with the same inclination angle on both sides. Step 2: Rotate the mold base material on the B-axis turntable to 120 degrees, and use the first type of tool with a tool angle of α mounted on the fly cutter head to machine the other two conical surfaces of the parallelogram unit, namely the corner surface A102 of the triangular pyramid A1, the corner surface A301 of the triangular pyramid A3, the corner surface C301 of the triangular pyramid C3, and the corner surface C202 of the triangular pyramid C2, with an inclination angle of α / 2. Step 3: Rotate the mold substrate on the B-axis turntable to 60 degrees, and use the first type of tool with a tool angle of α mounted on the fly cutter head to process the two opposite corner cones 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, with an inclination angle of α / 2; Step 4: Replace and install the second type of symmetrical cutting tool with a cutting angle of β on the flying cutter head. Adjust the tool to create an angle △, so that the inclination angle of the cutting edge on one side is β / 2-△ and the inclination angle of the cutting edge on the other side is β / 2+△. Based on the structure processed in Step 3, rotate the mold base material to the 0-degree position and use the second type of cutting tool to process and form the pyramidal surface B101 of triangular pyramid B1 and the pyramidal surface C303 of triangular pyramid C3, with an inclination angle of β / 2-△; at the same time, form the pyramidal surface A303 of triangular pyramid A3 and the pyramidal surface D101 of triangular pyramid D1, with an inclination angle of β / 2+△. Step 5: Rotate the mold base material in sequence to 120 degrees, and use the second type of tool to process and form the pyramidal surface B102 of the triangular pyramid B1 and the pyramidal surface C103 of the triangular pyramid C1, with an inclination angle of β / 2-△. At the same time, form the pyramidal surface A203 of the triangular pyramid A2 and the pyramidal surface D102 of the triangular pyramid D1, with an inclination angle of β / 2+△. Step 6: Rotate the mold base material to 60 degrees in sequence, and use the second type of tool to process and form the pyramidal surface B103 of triangular pyramid B1 and the pyramidal surface C203 of triangular pyramid C2, with an inclination angle of β / 2-△; at the same time, form the pyramidal surface A103 of triangular pyramid A1 and the pyramidal surface D103 of triangular pyramid D1, with an inclination angle of β / 2+△. At this point, the mold for the microprism reflective film, composed of four different triangular pyramid structures—A with tilt angles of α / 2, α / 2, and β / 2+△; B1 with tilt angle of β / 2-△; C with tilt angles of α / 2, α / 2, and β / 2-△; and D1 with tilt angle of β / 2+△—has been processed and formed.

8. The method for manufacturing a mold for a microprism reflective film integrating four triangular pyramid combinations according to claim 7, characterized in that: The first type of tool has a cutting angle α = 70.50 degrees; the second type of tool is a symmetrical tool with a cutting angle β = 70.72 degrees. During machining, the first type of tool is used first, and machining is performed in an array with B-axis rotation angles of 0 degrees, 60 degrees, and 120 degrees, and an intercept pitch of 0.407 mm. The first three cuts form a large triangular pyramid. Then, the second type of tool is used, and machining is performed in an array along the center line connecting the edges of the large triangular pyramid with B-axis rotation angles of 0 degrees, 120 degrees, and 60 degrees, and an intercept pitch of 0.407 mm. The resulting shape consists of a parallelogram unit array. The composite microprism reflective film consists of a parallelogram unit containing eight triangular pyramids with a side length of 235 micrometers. The three reflective surfaces of the triangular pyramid A, which accounts for 3 / 8 of the area, have tilt angles of 35.25°, 35.25°, and 35.41°, respectively. The three reflective surfaces of the triangular pyramid B, which accounts for 1 / 8 of the area, all have tilt angles of 35.31°. The three reflective surfaces of the triangular pyramid C, which accounts for 3 / 8 of the area, all have tilt angles of 35.25°, 35.25°, and 35.31°, respectively. The three reflective surfaces of the triangular pyramid D, which accounts for 1 / 8 of the area, all have tilt angles of 35.41°.

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