Roller mold of triangular pyramid microstructure and surface machining method of roller mold

Abstract

The invention relates to the technical field of optical film production, and discloses a roller mold of a triangular pyramid microstructure and a surface machining method of the roller mold. The engraving machining process of the surface of the mold is divided into multiple layers, and machining of each layer is divided into multiple sets such as 60-degree oblique engraving machining, 120-degree oblique engraving machining and 180-degree transverse engraving machining for machining; a triangular pyramid prism microstructure is formed on the surface of a roller mold through combination of multiple groups of carving machining at different angles, the machining process of each angle is divided into multiple times of machining again, and a jumping machining mode is adopted for each time of machining. On one hand, the situation that the surface quality of the die is insufficient due to extrusion in the machining process of continuously machining adjacent lines is avoided, on the other hand, Pitch errors are equally divided in a multi-time and jumping type machining mode, possible badness is divided to multiple positions, and therefore the occurrence amplitude of the badness is reduced, and the machining efficiency is improved. And finally, the purpose of improving the overall surface machining precision and the roller mold machining yield is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of optical film production, and in particular to a roller mold with a triangular pyramid microstructure and a surface processing method thereof. Background Art

[0002] Optical films are thin film materials applied to optical components or optical devices, which usually have specific optical properties, such as reflection, transmission, spectroscopy, polarization, etc. Optical films are widely used in various fields, including but not limited to glasses, camera lenses, displays, solar cells, and military and aerospace equipment.

[0003] In the film production process, molds play a vital role. They are mainly responsible for molding and shaping the film to ensure the uniform thickness and surface quality of the film. Therefore, the quality of the mold is closely related to the quality of film production. Common molds include flat-plate engraving molds and roller molds. Flat-plate engraving molds are prone to solidification of residual glue at the bottom of the flat-plate mold during the optical film molding process, and the film product is prone to poor appearance when demolding. At the same time, its molding area and length also have certain limitations. Compared with flat-plate engraving molds, roller molds are not prone to white spots of residual glue solidified at the bottom of the mold, and the production efficiency is also higher. Therefore, roller molds have obvious advantages and have been widely used.

[0004] In the roller mold, "MD prism" refers to the micro-prism (Microlens Array, MLA) structure, which is a tiny prism array made using micro-optical technology. The optical film of this structure has special optical properties, which can realize directional reflection or refraction of light, thereby changing the propagation path of light. Micro-prismatic optical films are widely used in liquid crystal display backlight modules to achieve better optical effects by increasing the utilization efficiency of light, improving the brightness and contrast of the display. Micro-prismatic optical films include high-performance optical films and reflective films produced using micro-prismatic technology. As important components of backlight modules, they are increasingly widely used in liquid crystal display applications. This optical film can effectively improve the utilization rate of light and reduce energy consumption through a specific micro-prismatic structure. It also has the advantages of simple production process and obvious brightening effect.

[0005] The prism structure on the surface of the roller mold is formed by surface engraving, and after the mold is used, its surface structure will be worn or degraded. Therefore, before it is used again, it is generally necessary to reprocess it to ensure the accuracy of the microstructure of the roller mold surface, thereby ensuring its accuracy in the processing of optical film products. The mold is generally processed by engraving on a high-precision lathe to process the mold surface to achieve the target surface quality.

[0006] The common methods of engraving the surface of roller molds include horizontal engraving and oblique engraving. Since the mold surface is engraved line by line, the process is time-consuming and there are inevitably certain errors in the process. This leads to the problem of splicing lines on the mold surface during the processing, that is, the distance between adjacent lines is uneven, which will cause the quality of the film product to degrade during the use of the mold.

[0007] In addition, the applicant has developed a new type of triangular pyramid prism microstructure roller mold product based on the special needs of the product to meet the production needs of special optical film products. The surface prism structure of the roller mold needs to be processed by a combination of horizontal engraving and oblique engraving (such as Figure 1 ), therefore, the processing process also has the problem of splicing lines. At the same time, if there are deviations in horizontal engraving and / or oblique engraving and inconsistent processing depth during the processing, it is also easy to have small triangular pyramids (such as Figure 2 ), which ultimately affects the forming effect of the optical film surface microstructure. Therefore, how to ensure the surface processing quality of the triangular pyramid prism microstructure roller mold and ensure the mold processing yield has become an urgent problem to be solved.

[0008] SUMMARY OF THE INVENTION

[0009] The technical problem solved by the present invention is: how to avoid the occurrence of splicing lines and small triangular pyramids during mold processing, ensure the surface processing quality of the triangular pyramid prism microstructure roller mold, and ensure the mold processing yield.

[0010] The purpose of the present invention can be achieved by the following technical solutions:

[0011] A surface processing method for a roller mold with a triangular pyramid microstructure comprises the following steps:

[0012] Choose the mold: choose the roller mold of corresponding size according to the target product;

[0013] Mould installation: Fixedly install the selected roller mould on the processing equipment;

[0014] Parameter calculation: Calculate the number of processing lines of the mold; first, the circumference of the cross section of the roller mold is πR, where R is the roller diameter before processing minus twice the processing depth. Then, the number of lines divided in the mold surface processing process is calculated according to the number of processing lines 4n = circumference ÷ processing Pitch, where 4n is the total number of lines, n is the number of single lines, and n is an even number;

[0015] Mould processing: The processing process is divided into m layers, where m is a positive integer. After completing m layers of processing, the mould is removed from the processing equipment and transferred to the transfer area to complete the roller mould surface processing. The processing process of each layer is as follows:

[0016] Step 1, dividing the roller mold into four areas from the side view of the roller mold, and the critical points of each area are marked as 1, 2, 3, and 4 respectively;

[0017] Step 2. Perform 60° oblique engraving;

[0018] Step 21. Select critical point 1 as the starting point, and process the lines alternately in the directions of 1→2→3 and 1→4→3 each time, and there is a gap of three lines between two adjacent processed lines, until the critical point 3 is reached;

[0019] Step 22. Select critical point 3 as the starting point, and process the lines alternately in the directions of 3→2→1 and 3→4→1 each time, and there is a gap of three lines between two adjacent processed lines, until the critical point 1 is reached;

[0020] Step 23. Select critical point 2 as the starting point, and process the lines alternately in the directions of 2→3→4 and 2→1→4 each time, and there is a gap of three lines between two adjacent processed lines, until the critical point 4 is reached;

[0021] Step 24. Select critical point 4 as the starting point, and process the lines alternately in the directions of 4→3→2 and 4→1→2 each time, and there is a gap of three lines between two adjacent processed lines, until the critical point 2 is reached;

[0022] Step 3. Repeat steps 21 to 24 to perform 120° oblique engraving;

[0023] Step 4. Repeat steps 21 to 24 to perform 180° horizontal engraving.

[0024] In one embodiment of the present invention, in the process of selecting the mold, the dynamic balance index of the roller mold at a rotation speed of 1000 rpm is not more than 50g.

[0025] In one embodiment of the present invention, the concentricity is controlled within 2 μm during the process of installing the mold.

[0026] In one solution of the present invention, in the process of parameter calculation, four decimal places are taken for calculation, and the prism pitch error is controlled below 0.01 μm.

[0027] In one solution of the present invention: when the calculation structure is 10009 according to the number of processing lines 4n=perimeter÷processing Pitch, the total number of lines actually selected for processing is 10008.

[0028] In one solution of the present invention: when the calculation structure is 10007 according to the number of processing lines 4n=perimeter÷processing Pitch, the total number of lines actually selected for processing is 10000.

[0029] In one embodiment of the present invention, the mold processing process is carried out on a high-precision lathe with a concentricity error of less than 2 μm over an axial length of 2 m.

[0030] In one embodiment of the present invention, the mold processing is carried out in a processing area with a constant temperature environment, and the temperature fluctuation of the processing area is controlled within ±0.5°C.

[0031] In one embodiment of the present invention, the mold processing process also includes an adjustment process: the adjustment process is as follows:

[0032] First, the mold surface is partially processed in a single-layer processing manner, and then an adjustment pattern is formed by hand-turning the film and holding a UV lamp. The surface of the adjustment pattern is then observed under a high-power microscope to determine whether the processing depth of the roller mold surface is consistent. If not, the processing equipment is adjusted until the processing depth is consistent before the subsequent formal processing process.

[0033] A roller mold with a triangular pyramid microstructure, wherein the surface of the roller mold is carved to form the triangular pyramid microstructure by adopting the above processing method.

[0034] A roller mold with a triangular pyramid microstructure and a surface processing method thereof according to the present invention have at least one of the following technical effects:

[0035] This application divides the engraving process of the mold surface into multiple layers, and each layer is processed into multiple groups such as 60° oblique engraving, 120° oblique engraving and 180° horizontal engraving. Through multiple groups of engraving at different angles, a triangular pyramid prism microstructure is formed on the surface of the roller mold to meet the production needs of special optical film products. Before the mold processing process begins, an adjustment process is first performed to ensure that the depth of engraving at different angles is consistent to avoid the appearance of small triangular pyramids, which is a surface defect.

[0036] At the same time, the present application divides the processing of each angle into multiple times for processing, and each processing adopts a jump processing method, which can avoid the situation that the continuous processing of adjacent lines will cause the surface quality of the mold to be insufficient due to extrusion during the processing, and the error that may exist at the critical point 1 is dispersed to the four positions of critical points 1, 2, 3, and 4 through multiple and jump processing, thereby evenly dividing the pitch error and dividing the possible defects into four positions, thereby reducing the magnitude of the occurrence of the defect, and finally achieving the purpose of improving the overall surface processing accuracy and the processing yield of the roller mold. By using this method to process the roller mold, the quality accuracy within 0.01μm can be achieved.

[0037] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0039] Figure 1 It is a line diagram of the engraving process of the triangular pyramid microstructure of the present invention;

[0040] Figure 2 This is a schematic diagram of the principle of the small triangular pyramid defect of the present invention;

[0041] Figure 3 It is a schematic diagram of the roller mold of the present invention divided into four areas when viewed from the side. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0044] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0045] See also Figure 1-3The present invention is a roller mold with a triangular pyramid microstructure, whose surface is engraved to form a triangular pyramid-shaped microstructure to meet the production needs of special optical film products. The engraving process includes engraving at two angles: oblique engraving and horizontal engraving. In addition to the poor appearance of the splicing line existing in the horizontal engraving and oblique engraving, it is also easy to cause the appearance of the small triangular pyramid to be poor due to inconsistent processing depth or deviation of the horizontal engraving and oblique engraving. Therefore, the present application guarantees the surface processing quality and yield of the engraving of the roller mold with a triangular pyramid microstructure by controlling the processing method.

[0046] See also Figure 1-3 This embodiment provides a surface processing method for a roller mold with a triangular pyramid microstructure as described above. The processing method is performed using a high-precision lathe, and requires that the concentricity error of the axial length of 2m is within 2μm. The processing method includes the following steps:

[0047] Select the mold: Select the roller mold of the corresponding specifications and dimensions according to the target product, such as length, diameter, etc. During the selection process, since the horizontal and oblique engraving processes have relatively high requirements on the mold itself, the dynamic balance index of the mold is relatively high. During the selection process, the dynamic balance index of the roller mold at a speed of 1000 rpm is not more than 50g. In the actual processing process, it is preferred that the dynamic balance index of the mold can be controlled at about 20g (RPM 1000 rpm).

[0048] Mold installation: The selected roller mold is fixedly installed on the processing equipment, such as a high-precision lathe. During the installation process, the concentricity needs to be controlled within 2μm, and the roller body rotates stably to reduce the impact on the dynamic balance concentricity during processing.

[0049] Parameter calculation: Calculate the number of processing lines of the mold. First, the circumference of the cross section of the roller mold is πR, where R is the roller diameter before processing minus twice the processing depth. In this calculation process, take 4 decimal places (for example 0.0001), and control the prism Pitch error below 0.01μm. Then, according to the number of processing lines 4n = circumference ÷ processing Pitch, the number of lines divided by the mold surface processing process is calculated. In the calculation process, the four-fold method is selected for calculation, and at the same time, the number of single lines is ensured to be an even number. That is, 4n is the total number of lines, n is the number of single lines, and n is an even number. For example, the total number of lines is 10009, and the actual selection is to select a total number of lines of 10008. The actual total number of processing lines is 10008÷4=2502, thereby ensuring that the number of single lines is an even number. For example, when the total number of lines calculated based on the perimeter ÷ processing pitch is 10007, the actual total number of selected lines is 10000, not 10004, because 10004 ÷ 4 = 2501, and the number of single lines is not an even number.

[0050] Mold processing: During the processing, the concentricity of the roller surface needs to be controlled not to exceed 2μm, where the processing pitch unit is μm. In addition, it should be noted that most molds are made of copper, and the expansion coefficient of copper itself will change with temperature and produce adverse factors for processing. Therefore, the temperature control of the processing room must be strict, which is also a prerequisite for processing quality assurance. The ambient temperature fluctuates within ±1°C. At the same time, the processing area can be enclosed outside the processing equipment to form a processing area, and the temperature control of the processing area fluctuates within ±0.5°C. Specifically, during the processing, the processing process is divided into m layers, where m is a positive integer. For example, it can be divided into two layers for processing. The first layer is rough processing, which can take a larger processing amount, and the second layer is fine processing, which uses a smaller processing amount. In order to ensure accuracy, it can also be divided into more levels for sequential processing. The disadvantage is that the processing time will be extended. The processing of each layer is divided into three groups of processing, including 60° oblique engraving (the starting direction of the processing is at an angle of 60° with the horizontal axis of the roller mold), 120° oblique engraving and 180° horizontal engraving. A triangular pyramid microstructure is formed on the surface of the roller mold through three groups of processing processes at different angles. The processing of each group is divided into four processing processes for processing. After completing m layers of processing, the mold is removed from the processing equipment and transferred to the transfer area to complete the roller mold surface processing process. After the mold processing is completed, the concentricity of the roller surface is controlled within 2μm.

[0051] See also Figure 1-3 , the specific processing process of each layer is as follows:

[0052] Step 1: Divide the roller mold into four areas from the side view of the roller mold (see Figure 3 ), the critical points of each region are marked as 1, 2, 3, and 4;

[0053] Step 2. Perform 60° oblique engraving;

[0054] First, the roller mold is divided into four areas from the side view of the roller mold, and the critical points of each area are 1, 2, 3, and 4 respectively.

[0055] Step 21. The first processing process is cross-made in the directions of (1→2→3) and (1→4→3). That is, the first cut processes the first line on one side (left) of the critical point 1, the second cut processes a line on the other side (right) of the starting point, the third cut processes a line on the left side of the starting point 1, and the fourth cut processes a line on the right side of the starting point, and so on and so forth until both sides are processed to the position of the opposite critical point 3. In this processing process, a jump processing method is adopted, that is, the position of the lines processed by two adjacent cuts is separated by three lines. For example, the number of lines to be processed on the surface of the roller mold is 10000, and they are marked as line 1, line 2, line 3, line 4, line 5, line 6, line 7, line 8... line 10000 according to the directions of critical points 1, 2, 3, and 4, respectively. Then, the processing order of the lines in the processing process is line 1, line 9997, line 5, line 9993, line 9, line 8999..., and the cross processing is carried out in this way until the position of the opposite point 3 is processed.

[0056] Step 22. The second processing selects critical point 3 as the starting point, and processes in the two directions (3→2→1) and (3→4→1) until the critical point 1 is reached. The cross-processing method is the same as the first cross-processing method, and a jump processing method is used. There are three lines between each two processing cuts. The jump processing method of this processing is the same as the first processing.

[0057] Step 23. The third processing selects critical point 2 as the starting point, and processes in two directions (2→3→4) and (2→1→4) in a cross-processing manner, with three lines between two adjacent processed lines, until the processing reaches the opposite critical point 4. The jumping processing method of this processing is the same as the first processing.

[0058] Step 24. The fourth processing selects critical point 4 as the starting point, and processes in two directions (4→3→2) and (4→1→2) in a cross-processing manner, with three lines between two adjacent processed lines, until the processing reaches the position of the opposite critical point 2. The jumping processing method of this processing is the same as the first processing.

[0059] Step 3. Repeat steps 21 to 24 to perform 120° oblique engraving;

[0060] Step 4. Repeat steps 21 to 24 to perform 180° horizontal engraving.

[0061] After the first processing to the fourth processing, the jump processing method is used to complete the 60° oblique engraving processing, 120° oblique engraving processing and 180° horizontal engraving processing in the first layer of the roller mold in four times, and then the second layer (finishing processing), the third layer... can be processed in the same way. By adopting the jump processing method, on the one hand, it is avoided that the continuous processing of adjacent lines will cause the surface quality of the mold to be insufficient due to extrusion during the processing process. On the other hand, through four processings, each of which is a jump processing method, the error that may have existed at the critical point 1 (the existing sequential processing method, the error will accumulate between the starting point and the final point) is dispersed to the four positions of critical points 1, 2, 3, and 4, so that the pitch error is evenly divided, and the possible defects are divided into four positions, thereby reducing the defects and improving the overall surface processing accuracy. Finally, the quality accuracy within the error of 0.01μm can be achieved, thereby achieving the effect of reducing the obvious difference in the surface texture of the roller mold, and finally achieving the purpose of improving the processing quality of the roller mold. At the same time, because it is divided into multiple layers, and each layer adopts multiple, jump-type processing methods, even if the tool suddenly wears out, there will be no obvious large-area color difference. Instead, because of the sharing, the existence of color difference is greatly reduced, thereby improving the yield of roller mold engraving processing. In summary, by adopting this method, the mold processing splicing line can be eliminated or minimized, and when making products, it can be ensured that there is no obvious appearance color difference or obvious dividing line and other poor appearance in routine inspections, ensuring the product width and overall yield, ensuring product performance while improving the process speed and yield. In addition, in this embodiment, the processing process is divided into four times as an exemplary statement, which does not only mean that it can be divided into four areas and processed four times, but can also be adjusted accordingly according to the situation.

[0062] The mold processing process also includes an adjustment process: the adjustment process is as follows: first, the mold surface is locally processed in a single-layer processing manner. The local processing can be processing of a partial area or processing of a section at one end of the mold, which is mainly used to adjust the processing depth between processing at different angles to ensure consistent processing depth. After completing the local processing in a single-layer processing manner, the film is hand-turned and formed with a handheld UV lamp to transfer an adjustment pattern, and then the surface of the adjustment pattern is observed under a high-power microscope. The surface texture of the adjustment pattern after transfer is used to determine whether the processing depth of the roller mold surface is consistent. If not, the processing equipment is adjusted until the processing depth is consistent, thereby ensuring the consistency of the depth during engraving processing at different angles, and ultimately ensuring the molding quality of the triangular pyramid microstructure on the roller mold surface.

[0063] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A surface processing method for a roller mold with a triangular pyramid microstructure, characterized in that: The steps include: Mould installation: Select the roller mould of corresponding size according to the target product and install the selected roller mould on the processing equipment; Parameter calculation: Calculate the number of processing lines of the mold; first, the circumference of the cross section of the roller mold is πR, where R is the roller diameter before processing minus twice the processing depth. Then, the number of lines divided in the mold surface processing process is calculated according to the number of processing lines 4n = circumference ÷ processing Pitch, where 4n is the total number of lines, n is the number of single lines, and n is an even number; Mould processing: The processing process is divided into m layers, where m is a positive integer. After completing m layers of processing, the mould is removed from the processing equipment and transferred to the transfer area to complete the roller mould surface processing. The processing process of each layer is as follows: Step 1, dividing the roller mold into four areas from the side view of the roller mold, and the critical points of each area are marked as 1, 2, 3, and 4 respectively; Step 2. Perform 60° oblique engraving; Step 21. Select critical point 1 as the starting point, and process the lines alternately in the directions of 1→2→3 and 1→4→3 each time, and there is a gap of three lines between two adjacent processed lines, until the critical point 3 is reached; Step 22. Select critical point 3 as the starting point, and process the lines alternately in the directions of 3→2→1 and 3→4→1 each time, and there is a gap of three lines between two adjacent processed lines, until the critical point 1 is reached; Step 23. Select critical point 2 as the starting point, and process the lines alternately in the directions of 2→3→4 and 2→1→4 each time, and there is a gap of three lines between two adjacent processed lines, until the critical point 4 is reached; Step 24. Select critical point 4 as the starting point, and process the lines alternately in the directions of 4→3→2 and 4→1→2 each time, and there is a gap of three lines between two adjacent processed lines, until the critical point 2 is reached; Step 3. Repeat steps 21 to 24 to perform 120° oblique engraving; Step 4. Repeat steps 21 to 24 to perform 180° horizontal engraving.

2. The surface processing method of a roller mold with a triangular pyramid microstructure according to claim 1 is characterized in that: In the process of selecting the mold, the dynamic balance index of the roller mold at a rotation speed of 1000 rpm should not exceed 50g.

3. The surface processing method of a roller mold with a triangular pyramid microstructure according to claim 1 is characterized in that: During the mold installation process, the concentricity is controlled within 2μm.

4. The surface processing method of a roller mold with a triangular pyramid microstructure according to claim 1 is characterized in that: In the process of parameter calculation, four decimal places are taken for calculation, and the prism pitch error is controlled below 0.01μm.

5. The surface processing method of a roller mold with a triangular pyramid microstructure according to claim 1 is characterized in that: When the structure is calculated as 10009 according to the number of processing lines 4n = perimeter ÷ processing Pitch, the total number of lines actually selected for processing is 10008.

6. The surface processing method of a roller mold with a triangular pyramid microstructure according to claim 1 is characterized in that: When the calculation structure is 10007 according to the number of processing lines 4n = perimeter ÷ processing Pitch, the total number of lines actually selected for processing is 10000.

7. The surface processing method of a roller mold with a triangular pyramid microstructure according to claim 1 is characterized in that: The mold processing process is carried out on a high-precision lathe with an axial length of 2m and a concentricity error of less than 2μm.

8. The surface processing method of a roller mold with a triangular pyramid microstructure according to claim 1 is characterized in that: The mold processing process is carried out in a processing area with a constant temperature environment, and the temperature fluctuation in the processing area is controlled within ±0.5℃.

9. The surface processing method of a roller mold with a triangular pyramid microstructure according to claim 1, characterized in that: The mold processing process also includes the adjustment process: The adjustment process is as follows: First, the mold surface is locally processed in a single-layer processing manner, and then an adjustment pattern is formed by hand-turning the film with a handheld UV lamp. The surface of the adjustment pattern is then observed under a high-power microscope to determine whether the processing depth of the roller mold surface is consistent. If not, the processing equipment is adjusted until the processing depth is consistent.

10. A roller mold with a triangular pyramid microstructure, characterized in that: The roller mold is engraved to form a triangular pyramid surface microstructure according to the surface processing method described in any one of claims 1 to 9.

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