Method for manufacturing optical film

Abstract

Provided is a manufacturing method for manufacturing an optical film that is cut by end mill processing several times, and that allows easy determination of whether or not finishing has been performed. The manufacturing method for an optical film according to the present application includes a workpiece formation step of laminating a plurality of optical films to form a workpiece, and an end mill processing step of cutting an outer peripheral surface of the workpiece with an end mill, the end mill processing step including a rough cutting step of rough cutting the outer peripheral surface of the workpiece with an end mill, and a finishing step of finishing the outer peripheral surface of the workpiece that has been rough cut, the rough cutting step including providing an uncut portion on the outer peripheral surface of the workpiece, and the finishing step including cutting the uncut portion.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an optical film. Background Art

[0002] Various optical films (e.g., polarizing plates) are used in image display devices such as mobile phones and notebook personal computers to achieve image display and / or improve the performance of the image display. In recent years, optical laminates are also expected to be used in automobile dashboards and smart watches, and it is expected that the shape of the optical laminates can be processed into a desired shape. During such processing, there is a case where the end face is cut by an end mill. In this case, the end milling is performed several times on the cut surface in a manner of performing fine processing after roughing.

[0003] In end milling, a process error could occur where a rough cut is followed by a product that has not been finished and is then passed on to the next process. Visual quality inspections are difficult to determine whether the product has been finished, and introducing a specialized inspection device would complicate the process and be cost-effective.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-187781

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-022140 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] The present invention has been made to solve the above-mentioned conventional problems, and its main object is to provide a manufacturing method for manufacturing an optical film cut by multiple end milling processes, which can easily determine whether or not the film has been finished.

[0010] Means for solving problems

[0011] The manufacturing method of the optical film of the present invention includes stacking multiple optical films to form a workpiece, and an end milling process of cutting the outer peripheral surface of the workpiece with an end mill. The end milling process includes a roughing process of roughing the outer peripheral surface of the workpiece with an end mill, and fine-machining the roughed outer peripheral surface of the workpiece with an end mill. The roughing process includes setting an uncut portion on the outer peripheral surface of the workpiece, and the fine-machining includes cutting the uncut portion.

[0012] In one embodiment, the method for manufacturing the above-mentioned optical film includes: in the above-mentioned rough cutting process, when cutting starts, the above-mentioned end mill is moved in a direction inclined relative to the workpiece when viewed from above, and the end mill is contacted with the workpiece, and the part where cutting starts and the part where cutting ends are set at different positions on the workpiece, thereby forming the uncut part.

[0013] In one embodiment, the method for manufacturing the optical film includes: in the rough cutting step, at the end of cutting, moving the end mill away from the workpiece while moving the end mill in a direction inclined relative to the workpiece in a plan view.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to provide a method for manufacturing an optical film cut by multiple end milling operations, in which the presence or absence of finish machining can be easily determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic perspective view for explaining an example of cutting processing of the optical film of the present invention.

[0017] Figure 2 This is a schematic perspective view of an example of an end mill used for cutting in the method for producing an optical film of the present invention.

[0018] Figure 3 (a) is a schematic cross-sectional view when viewed from the axial direction for explaining another example of a cutting unit used for cutting in the method for producing an optical film of the present invention, Figure 3 (b) Yes Figure 3 (a) is a schematic perspective view of the cutting unit.

[0019] Figure 4 (a) to (c) are schematic partial plan views of a workpiece showing an uncut portion in the method for producing an optical film of the present invention.

[0020] Figure 5 (a) and Figure 5 (b) is a schematic plan view illustrating a rough cutting step in the method for producing an optical film according to one embodiment of the present invention.

[0021] Figure 6 (a) and Figure 6 (b) is a schematic plan view illustrating a cutting process according to an embodiment of the present invention.

[0022] Figure 7 (a) and Figure 7 (b) is a schematic plan view illustrating a cutting process according to an embodiment of the present invention.

[0023] Figure 8 This is a schematic plan view of a workpiece for explaining one embodiment of the present invention.

[0024] Figure 9 (a) and Figure 9 (b) is a schematic plan view illustrating a cutting process according to an embodiment of the present invention.

[0025] Figure 10 (a) and Figure 10 (b) is a schematic plan view illustrating a cutting process according to an embodiment of the present invention.

[0026] Label Description

[0027] 1…workpiece; 20…end milling cutter. DETAILED DESCRIPTION

[0028] Below, specific embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to these embodiments. In addition, the accompanying drawings are schematically shown for easy observation, and the ratios and angles of length, width, thickness, etc. in the accompanying drawings are different from those in reality.

[0029] The method for producing an optical film by cutting of the present invention comprises the steps of laminating a plurality of optical films to form a workpiece and cutting the outer peripheral surface of the workpiece with an end mill.

[0030] <<Workpiece Formation>>

[0031] Figure 1 FIG1 is a schematic perspective view for explaining cutting processing, in which a workpiece 1 is shown. Figure 1As shown, a plurality of optical films are stacked to form a workpiece 1. When the workpiece is formed, the optical film is typically cut into any appropriate shape. Specifically, the optical film can be cut into a rectangle, a shape similar to a rectangle, or a shape suitable for the purpose (for example, a circle). In the example shown in the figure, the optical film is cut into a rectangle, and the workpiece 1 has outer peripheral surfaces (cutting surfaces) 1a and 1b facing each other and outer peripheral surfaces (cutting surfaces) 1c and 1d orthogonal to them. Preferably, the workpiece 1 is clamped from the top and bottom by a clamping unit (not shown). The total thickness of the workpiece is, for example, 8 mm to 100 mm, preferably 8 mm to 50 mm, more preferably 8 mm to 20 mm, even more preferably 9 mm to 15 mm, and most preferably about 10 mm. If it is such a thickness, it can prevent damage caused by the pressure of the clamping unit or the impact during cutting. The optical films are stacked so that the workpiece reaches such a total thickness. The number of optical films constituting the workpiece can be, for example, 10 to 500 sheets (10 to 300 sheets in one embodiment, and 10 to 50 sheets in another embodiment). The clamping unit (such as a clamp) can be composed of a soft material or a hard material. In the case of being composed of a soft material, its hardness (JIS A) is preferably 20° to 80°, more preferably 60° to 80°, and its thickness is, for example, 0.3 mm to 5 mm. When the hardness is too high, there may be residual indentations caused by the clamping unit. When the hardness is too low or too thick, misalignment occurs due to deformation of the clamp, and there may be insufficient cutting accuracy.

[0032] <<End Milling Process>>

[0033] Then, in the end mill processing step, the outer peripheral surface of the workpiece 1 is cut by the end mill 20. Cutting is performed by bringing the cutting edge of the end mill into contact with the outer peripheral surface of the workpiece 1. Cutting can be performed over the entire outer peripheral surface of the workpiece or only at a specified position. In addition, for a workpiece having a hole, the inner peripheral surface can also be cut by bringing the cutting edge of the end mill into contact with the inner peripheral surface of the hole. As the end mill 20, a straight shank end mill (ストレートエンドミル) can be representatively used. During the cutting process, only the end mill can be moved, only the workpiece can be moved, or both the end mill and the workpiece can be moved.

[0034] like Figure 2 and Figure 3 As shown, the end mill 20 has a rotation axis 21 extending along the stacking direction (vertical direction) of the workpiece 1 and a cutting edge 22 at the outermost diameter of the body configured to rotate around the rotation axis 21. Figure 2 As shown, the cutting edge 22 is formed as the outermost diameter twisted along the rotation axis 21 (which may have a predetermined twist angle), or as shown in FIG. Figure 3The structure shown is extended in a direction substantially parallel to the rotation axis 21 (the twist angle can be 0°). In addition, "0°" means substantially 0°, and also includes the case where the twist angle is small due to processing errors, etc. In the case where the cutting edge has a specified twist angle, the twist angle is preferably less than 70°, more preferably less than 65°, and even more preferably less than 45°. The cutting edge 22 includes a cutting edge 22a, a cutting surface 22b and a retreat surface 22c. The number of blades of the cutting edge 22 can be appropriately set as long as the desired number of contacts described later can be obtained. Figure 2 The number of blades is 3. Figure 3 The number of blades in the embodiment is two, but the number of blades can be one, four, or five or more. Preferably, the number of blades is two. This structure ensures blade rigidity and creates pockets, effectively discharging chip waste. In one embodiment, an end mill with a twist angle of 0° is used.

[0035] In the end milling process, the outer surface of the workpiece is roughed with an end mill, and the roughed outer surface of the workpiece is then finished with the end mill. Roughing and finishing are performed to improve cutting accuracy. In the roughing process, the outer surface of the workpiece is cut to a thickness of 0.1mm to 0.5mm, for example. In the finishing process, the outer surface of the rough-cut workpiece is cut to a thickness of 0.01mm to 0.2mm, for example. Furthermore, the ground surface may be cut several times with the end mill during both the roughing and finishing processes.

[0036] <Rough cutting process>

[0037] In the present invention, in the rough cutting step, an uncut portion is provided on the outer peripheral surface of the workpiece. Figure 4 (a) to (c) are schematic partial top views of the workpiece showing the uncut portion. The so-called uncut portion 11 is a portion that has not been subjected to cutting processing by the end mill. Typically, the uncut portion 11 is as follows: Figure 4 (a) to (c) are convex portions formed on the outer peripheral surface of the workpiece 1 .

[0038] The uncut portion is cut during the subsequent finishing process. According to the present invention, by providing an uncut portion during the roughing process, the presence or absence of the uncut portion can easily determine whether a product (or semi-finished product) has undergone finishing. In other words, a workpiece or optical film without an uncut portion can be identified as a normal product that has undergone finishing, while a workpiece or optical film with an uncut portion can be identified as a defective product that has not undergone finishing, or as a semi-finished product that should undergo finishing.

[0039] The shape of the uncut portion 11 can be determined by the trajectory of the end mill. In one embodiment, the uncut portion is formed by setting the starting point of cutting and the ending point of cutting at different positions on the workpiece. More specifically, as Figure 5 (a) The cutting by the end mill is started as shown in the moving path t of the end mill, and the end mill is moved so as to end the cutting before reaching the cutting starting point a and retreat from the workpiece, thereby forming Figure 5 (b) shows the uncut portion 11.

[0040] The shape of the uncut portion 11 is not particularly limited, and examples thereof include Figure 4 The shapes shown in (a) to (c). The width of the uncut part ( Figure 4 The width w) of the uncut portion is preferably 0.1 mm to 30 mm, more preferably 0.5 mm to 10 mm, and even more preferably 1 mm to 2 mm. Figure 4 The height h) in the embodiment is preferably 0.05 mm to 1 mm, more preferably 0.1 mm to 0.5 mm.

[0041] In one embodiment, the outer diameter of the end mill used in the roughing step is 10 mm or less, preferably 3 mm to 9 mm, and more preferably 4 mm to 6 mm. In addition, the "outer diameter of the end mill" in this specification refers to twice the distance from the rotation axis to a cutting edge.

[0042] The cutting conditions during the roughing process can be appropriately set depending on the desired shape. For example, the end mill rotation speed is preferably 1000 rpm to 60,000 rpm, more preferably 10,000 rpm to 40,000 rpm. The feed rate of the end mill is preferably 500 mm / min to 10,000 mm / min, more preferably 500 mm / min to 2,500 mm / min. In this specification, the speed of the end mill refers to the relative speed to the workpiece.

[0043] In one embodiment, at the start of cutting, the end mill is moved in a direction inclined relative to the workpiece when viewed from above while the end mill is brought into contact with the workpiece. In this specification, the "direction inclined relative to the workpiece" at the start of cutting refers to a direction, with respect to the cutting start point a, that forms an angle x( Figure 6The angle x in the direction is less than 60°. Furthermore, the so-called "direction inclined relative to the workpiece" refers to a direction that does not include a direction perpendicular to the workpiece or a direction close to perpendicular to the workpiece, that is, it also includes a direction in which the angle x is 0°. In addition, in this specification, the angle x is referred to as the travel angle x of the end mill at the start of cutting. When the cutting starting point a is located on a straight line, the travel angle x ( Figure 6 ), when the cutting starting point a is on the curve, the travel angle x( Figure 7 ). In addition, in this specification, the so-called "cutting starting point a" refers to the position where the end mill starts to move in order to cut the outer periphery of the workpiece of a predetermined thickness.

[0044] In one embodiment, in the rough cutting process, at the start of cutting, the end mill is moved in a direction inclined relative to the workpiece when viewed from above, while the end mill is brought into contact with the workpiece, and the starting point and ending points of the cutting are set at different positions on the workpiece, thereby forming an uncut portion.

[0045] Figure 6 (a) and Figure 6 (b) is a schematic plan view illustrating a cutting process according to an embodiment of the present invention. Figure 7 (a) and Figure 7 (b) is a schematic top view illustrating another embodiment of the cutting process of the present invention. Figure 6 (a) and Figure 6 (b) and Figure 7 (a) and Figure 7 In (b), the movement of the end mill at the start of cutting (relative movement with respect to the workpiece 1) is represented as a trajectory ts when viewed from above. Figure 6 In (a) and (b), the workpiece 1 is roughly rectangular. Figure 7 In (a) and (b), the outer contour of the workpiece 1 includes a curve. The trajectory ts of the end mill at the start of cutting can be as follows: Figure 6 (a) and Figure 7 (a) can also be a curve Figure 6 (b) and Figure 7(b) The straight line shown. As described above, the travel angle x of the end mill at the start of cutting is less than 60°, preferably between 0° and 60°, more preferably between 0° and 45°, even more preferably between 0° and 40°, and particularly preferably between 0° and 35°. As described above, the travel angle x can be 0°. For example, when the outer contour of the workpiece 1 includes a curve, the travel angle x can be set to 0°. In one embodiment, when the workpiece 1 is roughly rectangular, the travel angle x can be set to an angle greater than 0°. By moving the end mill in a direction inclined relative to the workpiece while contacting the workpiece, the occurrence of unnecessary recesses at the starting point of cutting can be prevented. The closer the travel angle x of the end mill at the start of cutting is to 0°, the better. In one embodiment, the travel angle x is less than 5° (preferably less than 3°, more preferably less than 1°, and even more preferably less than 0.5°).

[0046] In one embodiment, the travel trajectory ts of the end mill at the start of cutting is curved. By setting the travel trajectory ts of the end mill at the start of cutting to be curved, the effect of the invention of the present application is more significant. In the case where the travel trajectory ts is curved, the travel angle x of the end mill at the start of cutting is determined by the tangent us of the travel trajectory ts at the cutting start point a and the side A of the workpiece or the tangent B at the cutting start point a. In one embodiment, the end mill and the workpiece are brought close to and abutted while the workpiece is rotated in a plane, so that the end mill moves relative to the workpiece along the curved travel trajectory ts. When the end mill and the workpiece are brought close, the workpiece can be brought close to the fixed end mill, the end mill can be moved linearly to bring the end mill and the workpiece close, or the end mill and the workpiece can be moved linearly to bring the end mill and the workpiece close.

[0047] If the end mill's trajectory ts at the start of cutting is curved, the radius of curvature of the trajectory ts is preferably at least half the end mill's outer diameter, more preferably greater than the end mill's outer diameter, even more preferably at least 110% of the end mill's outer diameter, particularly preferably at least 130%, and most preferably at least 150%. Setting this range prevents the formation of unwanted recesses at the cutting start point a. Furthermore, if the end mill's trajectory ts at the start of cutting is curved, the radius of curvature of the trajectory ts is preferably at least 4 mm, more preferably at least 6 mm, and even more preferably at least 7.5 mm.

[0048] The speed of the end mill when the end mill is brought into contact with the workpiece is preferably slower than the feed speed of the end mill during cutting (when the cut surface of the workpiece is cut with the end mill). By slowing down the speed of the end mill at the start of cutting, the shaking of the workpiece can be suppressed. In one embodiment, the speed of the end mill when the end mill is brought into contact with the workpiece is preferably 400 mm / min to 1200 mm / min, more preferably 500 mm / min to 900 mm / min. In one embodiment, for example, in the case of cutting the inner circumference of a workpiece having a hole, the speed of the end mill when the end mill is brought into contact with the workpiece is preferably 30 mm / min to 1200 mm / min, more preferably 50 mm / min to 1000 mm / min.

[0049] The shape of the workpiece (ie, optical film) can be set to any appropriate shape. Figure 6 In addition to the roughly rectangular shape shown in the figure, roughly polygonal, roughly circular, roughly elliptical, etc. can also be mentioned. Moreover, the shape of the workpiece can also be a shape formed by appropriately combining straight lines and curves, or a shape composed of multiple curves with different curvatures. In addition, the above-mentioned workpiece may not be a pure rectangle, polygon, circle, ellipse, etc., but may also be a shape in which a special-shaped part is added to these shapes. In this specification, for example, a rectangle with a special-shaped part added is included in the "rough rectangle". As a special-shaped part, for example, in addition to Figure 6 In addition to the recessed portion shown, there may be convex portions, holes, etc. Furthermore, the workpiece may be in a shape obtained by curving the corners of a rectangle.

[0050] In addition, the above-mentioned cutting method (specifically, the trajectory of the end mill at the beginning of the cutting and the trajectory of the end mill at the end of the cutting described later) can also be applied to the following Figure 8 The workpiece 1 ′ shown has a hole 11 , and the inner peripheral surface of the hole 11 is cut.

[0051] In one embodiment, at the end of cutting, the end mill is moved away from the workpiece while moving in a direction inclined relative to the workpiece when viewed from above. In this specification, the "direction inclined relative to the workpiece" at the end of cutting refers to a direction in which, with respect to the cutting end point b, the end mill, in front of the direction of travel of the end mill before the end of cutting, forms an angle y ( Figure 9The angle y in the direction is less than 60°. As mentioned above, the so-called "direction inclined relative to the workpiece" refers to a direction that does not include a direction perpendicular to the workpiece or a direction close to perpendicular to the workpiece, that is, it also includes a direction in which the angle y is 0°. In addition, in this specification, the angle y is referred to as the travel angle y of the end mill at the end of cutting. When the cutting end point b is located on a straight line, the travel angle y ( Figure 9 ), when the cutting end point b is on the curve, the travel angle y of the end mill at the end of the cutting is determined by the tangent line B' of the workpiece at the cutting end point b and the travel trajectory of the end mill ( Figure 10 ).

[0052] Figure 9 (a) and Figure 9 (b) is a schematic plan view illustrating a cutting process according to an embodiment of the present invention. Figure 10 (a) and Figure 10 (b) is a schematic top view illustrating another embodiment of the cutting process of the present invention. Figure 9 (a) and Figure 9 (b) and Figure 10 (a) and Figure 10 In (b), the movement of the end mill at the end of cutting (relative movement with respect to the workpiece 1) is represented as a trajectory te when viewed from above. Figure 9 In (a) and (b), the workpiece 1 is roughly rectangular. Figure 10 In (a) and (b), the outer contour of the workpiece 1 includes a curve. The trajectory te of the end mill at the end of cutting can be as follows Figure 9 (a) and Figure 10 (a) can also be a curve Figure 9 (b) and Figure 10 (b) The straight line shown. As described above, the travel angle y of the end mill at the end of cutting is less than 60°, preferably more than 0° and less than 60°, more preferably more than 0° and less than 45°, even more preferably more than 0° and less than 40°, and particularly preferably more than 0° and less than 35°. As described above, the travel angle y can be 0°. For example, when the outer contour of the workpiece 1 includes a curve, the travel angle y can be set to 0°. In one embodiment, when the workpiece 1 is roughly rectangular, the travel angle y can be set to an angle greater than 0°. In this specification, the so-called "cutting end point b" refers to the part where the end mill that moves in a manner of cutting the periphery of a workpiece of a specified thickness changes its travel direction to a direction away from the workpiece and ends cutting. In one embodiment, the distance between the "cutting start point a" and the "cutting end point b" is equivalent to the width w of the uncut portion.

[0053] Preferably, the travel trajectory te of the end mill at the end of cutting is curved. By setting the travel trajectory te of the end mill at the end of cutting to be curved, the above-mentioned effect is more significant. In the case where the travel trajectory te is curved, the travel angle y of the end mill at the end of cutting is determined by the tangent ue of the travel trajectory te at the cutting end point b and the side A of the workpiece or the tangent B' at the cutting end point b. In one embodiment, the end mill is moved away from the workpiece while rotating the workpiece in a plane, so that the end mill moves relative to the workpiece along a curved travel trajectory te. When moving the end mill away from the workpiece, the workpiece can be moved away from the fixed end mill, the end mill can be moved linearly to move the end mill away from the workpiece, or the end mill and the workpiece can be moved linearly to move the end mill and the workpiece away from the end mill.

[0054] If the end mill's trajectory te is curved at the end of cutting, the radius of curvature of the trajectory te is preferably at least half the end mill's outer diameter, more preferably greater than the end mill's outer diameter, even more preferably at least 110% of the end mill's outer diameter, particularly preferably at least 130%, and most preferably at least 150%. Setting this range prevents the generation of unwanted steps and burrs at the cutting end point b. Furthermore, if the end mill's trajectory te is curved at the end of cutting, the radius of curvature of the trajectory te is preferably at least 4 mm, more preferably at least 6 mm, and even more preferably at least 7.5 mm.

[0055] The speed of the end mill when the end mill is moved away from the workpiece is preferably slower than the feed speed of the end mill during cutting (when the cut surface of the workpiece is cut with the end mill). By slowing down the speed of the end mill at the end of cutting, the shaking of the workpiece can be suppressed. In one embodiment, the speed of the end mill when the end mill is moved away from the workpiece is preferably 400 mm / min to 1200 mm / min, more preferably 500 mm / min to 900 mm / min. In one embodiment, for example, in the case of cutting the inner circumference of a workpiece having a hole, the speed of the end mill when the end mill is moved away from the workpiece is preferably 30 mm / min to 1200 mm / min, more preferably 50 mm / min to 1000 mm / min.

[0056] <Finishing>

[0057] After the roughing step, the outer peripheral surface of the rough-cut workpiece is finished by cutting with an end mill. In the finishing process, the outer peripheral surface of the workpiece including the uncut portion is cut.

[0058] In one embodiment, the outer diameter of the end mill used in the finishing process is 10 mm or less, preferably 3 mm to 9 mm, and more preferably 4 mm to 6 mm.

[0059] The cutting conditions during finishing can be appropriately set according to the desired shape. For example, the end mill rotation speed is preferably 1000 rpm to 60,000 rpm, more preferably 10,000 rpm to 40,000 rpm. The feed rate of the end mill is preferably 500 mm / min to 10,000 mm / min, more preferably 500 mm / min to 2500 mm / min.

[0060] In finishing, as described above, at the start of cutting, the end mill can be moved in a direction inclined relative to the workpiece when viewed from above while the end mill is brought into contact with the workpiece. Furthermore, at the end of cutting, the end mill can be moved in a direction inclined relative to the workpiece when viewed from above while the end mill is moved away from the workpiece. In finishing, the cutting start point and the cutting end point can be the same position, or the cutting start point and the cutting end point can be set to different positions, with the cutting end point being set in front of the direction of travel of the end mill relative to the cutting start point. Preferably, the cutting start point and the cutting end point are set to different positions, with the cutting end point b being set in front of the direction of travel of the end mill relative to the cutting start point. In this way, if the travel trajectories of the end mills during cutting are partially overlapped to complete the cutting, it is possible to effectively prevent the generation of unnecessary steps and fuzz at the end of cutting.

[0061] <<Optical Film>>

[0062] In one embodiment, the optical film includes a polarizer.

[0063] The optical film including the polarizer may be a polarizer alone or a film including the polarizer and other layers. As other layers, a protective layer for protecting the polarizer, a layer consisting of any appropriate optical functional layer, etc. may be cited. In one embodiment, a polarizing plate is used as the optical film including the polarizer. The polarizing plate may have a polarizer and a protective layer disposed on at least one side of the polarizer. Furthermore, as a film including the polarizer, a laminate of a polarizing plate and a surface protective film and / or a separator may be used. The surface protective film or the separator is releasably laminated on the polarizing plate by any appropriate adhesive. In this specification, the so-called "surface protective film" refers to a film that temporarily protects the polarizing plate, which is different from the protective layer (layer that protects the polarizer) possessed by the polarizing plate.

[0064] Polarizers are typically obtained by subjecting a resin film (e.g., a polyvinyl alcohol-based resin film) to various treatments, including swelling, stretching, dyeing with a dichroic substance (e.g., iodine, an organic dye, etc.), crosslinking, cleaning, and drying. Polarizers obtained through stretching are generally prone to cracking. However, the present invention enables cutting of optical films including polarizers while preventing cracking.

[0065] The thickness of the optical film including the polarizer is not particularly limited and can be appropriately adjusted depending on the intended use, for example, 20 μm to 200 μm. The thickness of the polarizer is also not particularly limited and can be appropriately adjusted depending on the intended use. The thickness of the polarizer is typically approximately 1 μm to 80 μm, preferably 3 μm to 40 μm.

[0066] The size of the optical film including the polarizer is not particularly limited and can be set to an appropriate size according to the purpose. In one embodiment, the optical film including the polarizer is rectangular including sides parallel to the absorption axis of the polarizer, the length of the side parallel to the absorption axis of the polarizer is 10 mm to 400 mm, and the length of the other sides is 10 mm to 500 mm. In this specification, the so-called "parallel" includes substantially parallel situations, specifically, including situations where the angle formed by two directions is 0° to 5°.

[0067] Industrial applicability

[0068] The optical film obtained by cutting according to the manufacturing method of the present invention can be used in liquid crystal display devices, organic EL display devices, etc. In addition, the optical film obtained by cutting can be used in rectangular image display units such as those typified by personal computers (PCs) and tablet terminals, and / or irregularly shaped image display units such as those typified by automobile dashboards and smart watches.

Claims

1. A method for manufacturing an optical film by cutting, characterized in that: include: Laminating a plurality of optical films to form a workpiece; as well as The end milling process of cutting the outer peripheral surface of the workpiece with an end mill, The end milling process includes a roughing process of roughing the outer peripheral surface of the workpiece with an end mill, and a finish process of finishing the roughed outer peripheral surface of the workpiece with an end mill. In the rough cutting process, a portion of the outer peripheral surface of the workpiece in the circumferential direction is not subjected to cutting, and a convex portion, that is, an uncut portion, is formed in the portion in the circumferential direction of the outer peripheral surface of the workpiece. The finishing includes cutting the uncut portion, The roughing process includes: at the beginning of cutting, causing the end mill to move in a direction inclined relative to the workpiece when viewed from above, while causing the end mill to contact the workpiece; at the end of cutting, causing the end mill to move in a direction inclined relative to the workpiece when viewed from above, while causing the end mill to move away from the workpiece. In the roughing process, with the cutting starting point as a reference, the angle formed by the moving direction of the end mill after the start of cutting and the edge of the workpiece including the cutting starting point or the tangent of the workpiece at the cutting starting point is less than 5°.

2. The method for producing a cut optical film according to claim 1, wherein: include: In the rough cutting step, the uncut portion is formed by setting the cutting start point and the cutting end point at different positions on the workpiece.

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