Roll master and method for manufacturing optical film

Abstract

To enhance visibility when handling an optical film, and easily form an antireflection area and a visible area on a surface of the optical film in the same processing step.SOLUTION: An optical film 1 comprises: a flexible base material 11; and a resin layer 12 laminated at least on one surface of the base material 11. The resin layer 12 includes: an uneven pattern area 2 formed with a fine uneven structure 20 comprising a plurality of protrusions 21 or recesses 22 arranged in a pitch P equal to or less than a wavelength of visible light; and a belt-shaped line marker area 3 formed with a plurality of ridge portions 31 arranged spaced apart from each other at a track pitch Pt equal to or more than the wavelength of the visible light.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention provides Roll master and a method for producing an optical film. [Background technology]

[0002] In recent years, one of the microfabrication technologies under development is imprinting technology, in which a roll master having a microrelief structure formed on its outer peripheral surface is pressed against a film to transfer the microrelief structure of the roll master to the film. Using this imprinting technology, for example, a microrelief structure (a so-called moth-eye structure) arranged at a period (pitch) equal to or shorter than the wavelength of visible light can be transferred onto the surface of a flexible, transparent plastic film (hereinafter referred to as a "transparent film"). This imparts an anti-reflection function to the transparent film, allowing the production of an optical film having anti-reflection function (hereinafter sometimes referred to as an "anti-reflection film").

[0003] In this case, roll-to-roll imprinting technology using a roll master enables efficient mass production of anti-reflection film rolls with a transferred microrelief structure. Specifically, in the imprinting process, a curable resin layer is applied to the surface of a long film substrate unwound from a roll, and the microrelief structure on the outer peripheral surface of the roll master is transferred to the curable resin layer. The curable resin layer is then cured to produce an anti-reflection film with a transferred microrelief structure on its surface, which is then wound into a film roll. The long anti-reflection film is then fed from the film roll and cut into individual pieces, resulting in a sheet of anti-reflection film with a predetermined shape. Furthermore, the sheet of anti-reflection film is cut or die-cut into the desired shape to produce shielding components such as eye shields and face shields.

[0004] For example, Patent Document 1 discloses an eye shield that has low reflected light and anti-fogging properties even under extremely high-intensity lighting systems, such as those used during surgical procedures. The eye shield in Patent Document 1 is made of a flexible transparent film, and both sides of the transparent film are formed with a moth-eye structure that has anti-reflection properties. This allows the transparent film to have a light transmittance (wavelength 550 nm) of 98.5% or more, providing a transparent eye shield that has low reflected light even under high-intensity lighting. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-155689 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as described in Patent Document 1, an anti-reflection film having high transmittance has a problem of low visibility during handling. That is, if the anti-reflection film has high transparency and reflects little light, as described above, users cannot or have difficulty visually recognizing the transparent anti-reflection film. This causes inconvenience when handling a sheet of the anti-reflection film (for example, when carrying or putting on or taking off an eye shield), such as difficulty in handling it properly or difficulty in finding a dropped anti-reflection film. For this reason, there has been a demand for a transparent region that occupies the majority of the anti-reflection film, while forming a visible region in part of it, to improve the ease of handling of the anti-reflection film by users.

[0007] On the other hand, in the manufacturing process of an anti-reflection film, if a separate step for forming a visible region in a part of the anti-reflection film is added in addition to the step of transferring the fine uneven structure for imparting the anti-reflection function, there is a problem that the productivity of the anti-reflection film decreases due to the increase in the number of steps. Therefore, it has been desired to make it possible to easily form a visible region in a part of the anti-reflection film without adding a step separate from the transfer step.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to improve visibility when handling an optical film, and to easily form an anti-reflection area and a visible area on the surface of the optical film in the same processing step. and a method for manufacturing an optical film. The reason is that. [Means for solving the problem]

[0009] In order to solve the above problem, according to one aspect of the present invention, A roll master used in the production of an optical film, a concave-convex pattern region having a fine concave-convex structure consisting of a plurality of convex or concave portions arranged at a pitch equal to or less than the wavelength of visible light; a strip-shaped line marker area having a plurality of grooves arranged at intervals at a track pitch equal to or greater than the wavelength of visible light; A roll master comprising: is provided.

[0010] The plurality of grooves are formed as spiral grooves on the outer peripheral surface of the roll master. This may be done.

[0011] The spiral groove has an inverted shape of a plurality of ridges formed in the line marker region of the optical film. This may be done.

[0012] The line marker areas are arranged at both ends of the roll master in the width direction. This may be done.

[0013] The width of the concave-convex pattern region is larger than the width of the line marker region. This may be done.

[0014] The track pitch of the grooves may be 500 nm or more and 1 mm or less. The groove portion The track pitch may be 1 μm or more and 10 μm or less.

[0015] The depth of the groovemay be substantially the same as the depth of the recesses of the fine concave-convex structure.

[0016] In the line marker area The groove portion is formed intermittently, The groove portion The part where no mark is formed is used to identify the part containing at least one of letters, symbols, or markers. is formed This may be done.

[0017] The identification information is The roll master The circumferential direction of the wheel may include a marker indicating a reference position of the wheel.

[0018] The identification information may include a character or symbol representing a lot number at the time of manufacturing the optical film.

[0019] The optical film may be a film roll in which a long film is wound.

[0020] The optical film may be a sheet of film having a predetermined shape.

[0021] In order to solve the above problems, according to another aspect of the present invention, A method for producing an optical film using the roll master, comprising: preparing a roll master including the concave-convex pattern region and the line marker region on an outer peripheral surface of the roll master; a step of applying a resin layer made of a curable resin to a surface of a substrate of the optical film; a step of transferring a transfer pattern including the fine concave-convex structure formed in the concave-convex pattern region of the roll master and the plurality of concave streak portions formed in the line marker region onto the resin layer of the optical film, thereby integrally forming the fine concave-convex structure in the concave-convex pattern region of the optical film and the plurality of convex streak portions in the line marker region of the optical film with the resin layer; A method for producing an optical film is provided, comprising: [Effects of the Invention]

[0022] As described above, according to the present invention, it is possible to improve visibility when handling an optical film, and to easily form an anti-reflection area and a visible area on the surface of the optical film in the same processing step. and a method for manufacturing an optical film. It is possible. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing a film roll of an optical film according to one embodiment of the present invention. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view showing the optical film according to the embodiment. [Figure 3] FIG. 2 is a partially enlarged perspective view showing the optical film according to the embodiment. [Figure 4] FIG. 2 is a plan view showing an example of a fine concave-convex structure in the optical film according to the embodiment. [Figure 5] FIG. 2 is a perspective view schematically showing a roll master according to the embodiment. [Figure 6] FIG. 2 is a block diagram showing a configuration of an exposure device used in manufacturing a roll master according to the embodiment. [Figure 7] 5A to 5C are schematic views illustrating an exposure method for a roll master according to the embodiment. [Figure 8] 5A and 5B are explanatory diagrams showing the correspondence between an exposure signal and an exposure pattern according to the embodiment; [Figure 9] 5A to 5C are process diagrams illustrating a method for manufacturing a roll master according to the embodiment. [Figure 10] 5A to 5C are process diagrams illustrating a method for manufacturing a roll master according to the embodiment. [Figure 11] 3A to 3C are process diagrams illustrating a method for producing an optical film according to the embodiment. [Figure 12] 3A to 3C are process diagrams illustrating a method for producing an optical film according to the embodiment. [Figure 13] FIG. 2 is a schematic diagram showing the configuration of a transfer device according to the embodiment. [Figure 14] 10 is a plan view showing an example of punching out a plurality of eye shields from the optical film according to the embodiment. FIG. [Figure 15] 4A to 4C are explanatory diagrams showing defects in the optical film and roll master according to the embodiment, and markers. [Figure 16] FIG. 2 is a plan view showing markers and cut-out characters formed in a line marker region of the optical film according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0025] [1. Optical film configuration] [1.1. Outline of optical film structure] First, the schematic configuration of an optical film 1 according to one embodiment of the present invention will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a perspective view showing a film roll of the optical film 1 according to one embodiment of the present invention. Fig. 2 is a partially enlarged cross-sectional view showing the optical film 1 according to this embodiment, taken along line AA in Fig. 1. Fig. 3 is a partially enlarged perspective view showing the optical film 1 according to this embodiment.

[0026] 1 to 3, the optical film 1 according to this embodiment is a transparent optical film (anti-reflection film) having an anti-reflection function and is transparent to visible light. For example, the optical film 1 is a moth-eye film having a microrelief structure 20 having anti-reflection properties formed on its surface. Note that, although this embodiment mainly describes an example in which a structure such as the microrelief structure 20 is formed on one surface of the optical film 1, the structure of the microrelief structure 20 may be formed on both surfaces (front and back) of the optical film 1.

[0027] Generally, when a periodic uneven structure is provided on the surface of a transparent film, diffraction occurs when light passes through the uneven structure, significantly reducing the linear component of the transmitted light. However, if the pitch of the uneven structure is shorter than the wavelength of the transmitted visible light, diffraction does not occur, and an effective anti-reflection effect can be obtained for light with a wavelength corresponding to the pitch and depth of the uneven structure. Such a fine uneven structure 20 having a pitch equal to or shorter than the wavelength of visible light is also called a moth-eye structure.

[0028] Forming the microrelief structure 20 on the surface of the optical film 1 can effectively suppress reflection at the interface between the optical film 1 and air. For example, when the optical film 1 is used as an eye shield or face shield, it is required to suppress reflection of external light and maintain good visibility for the user. From this perspective, the refractive index n of the optical film 1 is preferably 1.40 or more and 2.00 or less, and more preferably 1.43 or more and 2.00 or less. Furthermore, the transmittance of the optical film 1 at a wavelength of 550 nm is preferably 94.0% or more, more preferably 98.0% or more, and particularly preferably 98.5% or more.

[0029] The optical film 1 in the example of Fig. 1 is a film roll in which a long, flexible film is wound into a roll. However, the optical film of the present invention is not limited to this example and may be a flat film sheet having a predetermined shape (for example, a rectangular shape of predetermined dimensions). The optical film 1 unwound from the film roll is subjected to a forming process such as cutting or punching to obtain a finished optical film 1 (sheet).

[0030] As shown in FIGS. 1 to 3, the surface region of the optical film 1 includes a concave-convex pattern region 2 and a line marker region 3.

[0031] The concave-convex pattern region 2 is a transparent region (anti-reflection region) provided with an anti-reflection function by the fine concave-convex structure 20. The concave-convex pattern region 2 has a fine concave-convex structure 20 formed therein, which is composed of a plurality of convex portions 21 and concave portions 22 arranged at a pitch P equal to or less than the wavelength of visible light (for example, equal to or less than 350 nm). Therefore, the concave-convex pattern region 2 of the optical film 1 has an extremely low reflectance and a high light transmittance. For this reason, it is difficult for a user to visually recognize the transparent concave-convex pattern region 2 of the optical film 1 with the naked eye.

[0032] On the other hand, the line marker area 3 is an opaque area (visible area) that is visible to the user. The line marker area 3 does not have a fine uneven structure 20 like the uneven pattern area 2, and is not endowed with anti-reflection functionality. The line marker area 3 has a plurality of ridges 31 arranged in parallel with a gap between them. Each ridge 31 is a linear ridge extending along the longitudinal direction of the line marker area 3. The plurality of ridges 31 are arranged at a track pitch P of micrometer size (for example, 500 nm or more and 1 mm or less) that is equal to or greater than the wavelength of visible light. t The line marker region 3 in which the convex ridges 31 having such a periodic structure are formed functions as a diffraction grating that diffracts visible light.

[0033] The periodic structure of the multiple ridge portions 31 in this line marker region 3 causes diffraction and interference of light incident on the line marker region 3. As a result, the light (transmitted light, reflected light) exiting the line marker region 3 becomes diffused light that is separated into wavelengths (colors), resulting in rainbow-colored light that is visible to the user. In this way, the line marker region 3 is a visible region that has a diffraction grating function and emits rainbow-colored diffused light. As a result, the periodic structure of the multiple ridge portions 31 makes the line marker region 3 a visible region that functions as a diffraction grating.

[0034] The concave-convex pattern region 2 occupies most of the surface of the optical film 1. On the other hand, the line marker region 3 is a strip-shaped region extending in a predetermined direction (for example, the longitudinal direction of the strip-shaped optical film 1) on the optical film 1. The line marker region 3 is partially arranged in a narrow region on the surface of the optical film 1.

[0035] In the example of FIG. 1, the line marker region 3 is a strip-like region that extends linearly along the longitudinal direction (X direction) of the long optical film 1. Two line marker regions 3, 3 are arranged near both ends of the optical film 1 in the width direction (Y direction), and each line marker region 3, 3 extends linearly along the longitudinal direction (X direction) of the optical film 1. The concave-convex pattern region 2 is arranged so as to be sandwiched between these two elongated line marker regions 3, 3. In this way, in the example of FIG. 1, the wide concave-convex pattern region 2 is arranged in the center of the optical film 1 in the width direction (Y direction), and two strip-like line marker regions 3, 3 are arranged on both sides of the concave-convex pattern region 2 in the width direction (Y direction).

[0036] However, the arrangement pattern of the concave-convex pattern region 2 and the line marker region 3 is not limited to the example in FIG. 1 and can be modified in various ways. For example, only one line marker region 3 may be arranged, or three or more line marker regions 3 may be arranged. The line marker region 3 does not have to be a straight band, and may be any linear band shape, such as a curved band or a zigzag band. Furthermore, the line marker region 3 does not have to be a band shape, and may be any shape, such as a dotted line, a dashed line, a dotted line, a ring, a circle, an ellipse, or a polygon.

[0037] However, in order to ensure a wide transparent region of the optical film 1, it is preferable that the area of ​​the concave-convex pattern region 2 is larger than the area of ​​the line marker region 3. It is also preferable that the concave-convex pattern region 2 is disposed on the center side in the width direction of the optical film 1, and the line marker region 3 is disposed on the edge side in the width direction of the optical film 1.

[0038] As described above, the optical film 1 according to this embodiment is a transparent film with line markers. The optical film 1 has line marker regions 3 extending in a band-like shape in the circumferential direction of the roll adjacent to concave-convex pattern regions 2 in which a fine concave-convex structure 20 arranged at a pitch P equal to or less than the wavelength of visible light is formed. That is, the optical film 1 has line marker regions 3 that are opaque and easily visible, in addition to concave-convex pattern regions 2 that are transparent and difficult to see.

[0039] Therefore, although it is difficult for a user to see the light that passes through the transparent uneven pattern region 2, the user can easily see the rainbow-colored diffused light emitted from the line marker region 3, which functions as a diffraction grating. Therefore, by seeing the rainbow-colored diffused light from the line marker region 3 of the optical film 1, the user can recognize the presence, position, size, orientation, etc. of the optical film 1. As a result, transparent products using the optical film 1, such as shielding products such as eye shields and face shields, can be easily seen by the user. Therefore, visibility with the naked eye when handling the product can be improved, thereby improving user convenience.

[0040] [1.2. Layer structure of optical film] Next, the layer structure of the optical film 1 according to this embodiment will be described in more detail with reference to FIGS.

[0041] As shown in FIGS. 2 and 3, the optical film 1 includes a flexible, transparent substrate 11 and a transparent resin layer 12 laminated on at least one surface of the substrate 11. As such, the optical film 1 according to this embodiment has a two-layer structure including at least the substrate 11 and the resin layer 12. However, the present invention is not limited to this example. A multilayer structure of three or more layers may be formed by providing another intermediate layer, such as an adhesive layer (not shown) for improving adhesion, between the substrate 11 and the resin layer 12. Alternatively, a multilayer structure of three or more layers may be formed by providing resin layers 12, 12 on both the front and back surfaces of the substrate 11. Alternatively, a coating layer or the like may be added on the surface of the resin layer 12.

[0042] The substrate 11 is a flexible, transparent film substrate. The substrate 11 may be composed of a single sheet-like transparent member, or may be composed of a plurality of sheet-like transparent members laminated together. The thickness of the substrate 11 is appropriately selected depending on the application of the optical film 1, and it is preferable to impart flexibility, rigidity, thickness, etc. according to the application.

[0043] Examples of materials for the substrate 11 include transparent plastic materials and glass materials. Specifically, examples of plastic materials for the substrate 11 include methyl methacrylate (co)polymer, polycarbonate, styrene (co)polymer, methyl methacrylate-styrene copolymer, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, polyester, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polyurethane, and glass. Examples of glass materials for the substrate 11 include soda-lime glass, lead glass, hard glass, quartz glass, and liquid crystal glass. However, the material for the substrate 11 is not particularly limited to the materials exemplified above.

[0044] When a plastic material is used for the substrate 11, a primer layer (not shown) may be provided by surface treatment to further improve the surface energy, coatability, slipperiness, flatness, etc. of the surface of the plastic material. Examples of this primer layer include organoalkoxymetal compounds, polyester, acrylic-modified polyester, polyurethane, etc. Furthermore, to obtain the same effect as providing a primer layer, the surface of the substrate 11 may be subjected to corona discharge treatment, UV irradiation treatment, etc.

[0045] The substrate 11 can be formed, for example, by stretching the above-mentioned resin or diluting it in a solvent, forming it into a film, and drying it. The thickness of the substrate 11 is preferably selected appropriately depending on the application of the optical film 1, and is, for example, about 10 μm to 500 μm, preferably 50 μm to 500 μm, and more preferably 50 μm to 300 μm. When the thickness of the substrate 11 is 10 μm or more, the protective performance of the optical film 1 against flying objects is improved. On the other hand, when the thickness of the substrate 11 is 500 μm or less, the optical film 1 can be made lighter and, due to its flexibility, can be curved and deformed. Therefore, when the optical film 1 is used as a shielding material such as an eye shield, the wearing comfort is improved.

[0046] The resin layer 12 is a transparent resin layer, and is laminated on the surface of the substrate 11. In order to suppress internal reflection and improve contrast in the optical film 1, the refractive index of the resin layer 12 is preferably the same as that of the substrate 11. Furthermore, the resin layer 12 preferably has the same transparency as the substrate 11. In the resin layer 12, a concave-convex pattern of structures such as the fine concave-convex structure 20 in the concave-convex pattern region 2 and the plurality of convex streak portions 31 in the line marker region 3 is formed. In this embodiment, the fine concave-convex structure 20 and the plurality of convex streak portions 31 are formed on the same resin layer 12 in the same step by the same processing method (transfer processing using a roll master, which will be described later).

[0047] The resin layer 12 is a layer formed of a curable resin. The resin layer 12 is formed, for example, of a cured product of a curable resin composition (transfer material) such as an energy ray-curable resin composition. In the process of forming the resin layer 12, first, an energy ray-curable resin composition is applied as a transfer material onto the surface of the substrate 11, and a concave-convex pattern such as the micro concave-convex structure 20 is transferred to the energy ray-curable resin composition. Thereafter, the curable resin composition is cured by irradiation with energy rays. As a result, the resin layer 12 to which the concave-convex pattern has been transferred is formed on the surface of the substrate 11.

[0048] The energy ray-curable resin composition is a resin that has the property of being cured by irradiation with energy rays. Here, the energy rays may be, for example, ultraviolet rays, electron beams, infrared rays, laser beams, visible light, ionizing radiation (X-rays, α-rays, β-rays, γ-rays, etc.), microwaves, or high-frequency waves. From the viewpoint of ease of handling, for example, it is preferable to use an ultraviolet-curable resin composition as the energy ray-curable resin composition.

[0049] Furthermore, the energy ray-curable resin composition may contain, as necessary, a filler or a functional additive, etc. For example, the ultraviolet ray-curable resin composition may contain an acrylate or an initiator, and may also contain a monofunctional monomer, a bifunctional monomer, a polyfunctional monomer, etc.

[0050] Furthermore, the cured product of the energy ray-curable resin composition may have hydrophilic properties. For this reason, the energy ray-curable resin composition preferably contains one or more functional groups having hydrophilic properties. Examples of such functional groups having hydrophilic properties include a hydroxyl group, a carboxyl group, and a carbonyl group.

[0051] [1.3. Configuration of the fine concave-convex structure in the concave-convex pattern area] Next, the concave-convex pattern arrangement of the fine concave-convex structure 20 formed in the concave-convex pattern region 2 (antireflection region) of the optical film 1 according to this embodiment will be described in more detail with reference to Figures 2 to 4. Figure 4 is a plan view showing an example of the fine concave-convex structure 20 in the optical film 1 according to this embodiment.

[0052] 2 to 4, the fine concave-convex structure 20 (moth-eye structure) is made up of a plurality of convex portions 21 and concave portions 22 arranged at a pitch P that is equal to or less than the wavelength of visible light. By providing the fine concave-convex structure 20 in the resin layer 12 in the concave-convex pattern region 2 of the entire surface of the optical film 1, the surface (XY plane) of the concave-convex pattern region 2 becomes a concave-convex surface of the moth-eye structure.

[0053] The plurality of convex portions 21 constituting the microrelief structure 20 protrude in a direction (Z direction) perpendicular to the surface of the optical film 1. The concave portions 22 are recessed portions provided between the plurality of convex portions 21, 21 adjacent to each other.

[0054] The three-dimensional shape of the convex portion 21 may be various convex shapes, such as a cone shape (a bell shape, an elliptical truncated cone shape, etc.), a hemisphere, a semi-elliptical sphere, or a column. Examples of cone shapes include a cone shape with a pointed apex, a cone shape with a flat apex, and a cone shape with a convex or concave curved surface at the apex. Examples of cone shapes with a convex curved surface at the apex include quadratic curved surfaces such as a paraboloid. Furthermore, the cone surface of the cone shape may be curved in a concave or convex shape.

[0055] Furthermore, as shown in FIG. 4, the planar shape (dot shape) of the convex portions 21 when projected onto the surface (XY plane) of the optical film 1 is, for example, circular, but is not limited to this example and may be any shape having a curve, such as an ellipse or an oval.

[0056] The three-dimensional and planar shapes of the protrusions 21 are not limited to the shapes exemplified above. The circular, elliptical, spherical, hemispherical, semi-elliptical, and other shapes include not only mathematically defined perfect circles, ellipses, spheres, hemispheres, and semi-ellipses, but also slightly distorted shapes such as circles, ellipses, spheres, hemispheres, and semi-ellipses. In the examples shown in FIGS. 2 to 4, the multiple protrusions 21 of the microrelief structure 20 have the same size, shape, and height H. However, the configuration of the protrusions 21 is not limited thereto, and protrusions 21 having two or more different sizes, shapes, and heights may be formed on the surface of the resin layer 12.

[0057] The convex portions 21 and concave portions 22 of the micro concave-convex structure 20 (hereinafter sometimes referred to as "concave and convex portions of the micro concave-convex structure 20") are periodically arranged on the surface (XY plane) of the resin layer 12 at a predetermined pitch P. In this way, the micro concave-convex structure 20 has a periodic structure in which a plurality of convex portions 21 and concave portions 22 are periodically arranged on the XY plane. Here, the pitch P is the center-to-center distance (peak-to-peak distance) between adjacent convex portions 21, 21, or the center-to-bottom distance (bottom-to-bottom distance) between adjacent concave portions 22, 22, as shown in Figures 2 and 3. In this way, the pitch P of the concave and convex portions of the micro concave-convex structure 20 means the period of the periodic structure of the micro concave-convex structure 20.

[0058] The pitch P of the projections and recesses of the fine concave-convex structure 20 may be the arithmetic mean value (average pitch, average period) of the center-to-center distance between adjacent projections 21, 21 or recesses 22, 22 of the fine concave-convex structure 20. For example, a plurality of combinations of adjacent projections 21, 21 in the fine concave-convex structure 20 can be selected, the center-to-center distance between the projections 21, 21 of each combination can be measured, and the arithmetic mean value (average pitch, average period) of these measured values ​​can be calculated as the pitch P. The concave-convex pattern of the fine concave-convex structure 20 can be observed using, for example, a scanning electron microscope (SEM) or a cross-sectional transmission electron microscope (cross-sectional TEM).

[0059] In this embodiment, in order to impart anti-reflection properties to visible light, the pitch P of the concave-convex structure 20 is equal to or less than the wavelength of visible light. Here, the wavelength band of visible light is 360 nm to 830 nm, and the concave-convex structure 20 according to this embodiment has a regular arrangement of concave-convex portions at a pitch P less than the wavelength band of visible light. From this perspective, the pitch P of the concave-convex structure 20 is, for example, 350 nm or less, preferably 250 nm or less, and may be, for example, approximately 200 nm. Furthermore, the pitch P of the concave-convex structure 20 is, for example, 100 nm or more, preferably 120 nm or more, and more preferably 130 nm or more. A pitch P of less than 100 nm is undesirable because it may be difficult to form the concave-convex structure 20. On the other hand, a pitch P of more than 350 nm is undesirable because the intensity of diffracted light may increase, which may cause external light to be diffracted on the surface on which the concave-convex structure 20 is formed, thereby reducing the anti-reflection effect. If the pitch P is 350 nm or less, the anti-reflection properties of the fine concave-convex structure 20 can be improved, and a desired anti-reflection effect can be obtained.

[0060] 2 and 3, the height H of the convex portions 21 (or the depth of the concave portions 22) of the fine concave-convex structure 20 is not particularly limited, but is, for example, 100 nm or more and 400 nm or less, preferably 150 nm or more and 300 nm or less, and more preferably 200 nm or more and 300 nm or less. The height H of the convex portions 21 of the fine concave-convex structure 20 may be the arithmetic mean value (average height) of the heights of the multiple convex portions 21 that make up the fine concave-convex structure 20. For example, the heights of the multiple convex portions 21 that make up the fine concave-convex structure 20 can be measured, and the arithmetic mean value (average height) of these measured values ​​can be calculated as the height H.

[0061] The aspect ratio (height H / arrangement pitch P) of the convex portions 21 of the microrelief structure 20 is preferably 0.66 or more and 1.96 or less, more preferably 0.76 or more and 1.96 or less. When the aspect ratio is 0.66 or more, low reflectivity characteristics can be improved. On the other hand, when the aspect ratio is 1.96 or less, releasability when peeling the microrelief structure 20 from the roll master can be improved.

[0062] 4, the size D of the convex portions 21 of the microrelief structure 20 is the size (dot size) of the planar shape of the convex portions 21 (or concave portions 22) when the convex portions 21 (or concave portions 22) of the microrelief structure 20 are projected onto the surface (XY plane) of the optical film 1. For example, if the planar shape of the convex portions 21 is a circle, the size D of the convex portions is the diameter of the circle, and if the planar shape of the convex portions 21 is an ellipse, the size D of the convex portions is the major axis of the ellipse.

[0063] The size D of the projections and recesses of the fine concave-convex structure 20 is determined depending on the exposure resolution when the projection and recess pattern of the fine concave-convex structure is exposed to light on the outer peripheral surface of the roll master in the roll master manufacturing method described below. The size D of the projections and recesses of the fine concave-convex structure 20 is equal to or smaller than the pitch P of the projections and recesses (e.g., 350 nm or less), and is preferably equal to the pitch P of the projections and recesses, e.g., about 200 nm. For example, as shown in FIG. 4, by making the size D of the projections and recesses equal to the pitch P, multiple convex portions 21 can be densely arranged on the XY plane of the fine concave-convex structure 20, thereby reducing the area of ​​the gaps between adjacent convex portions 21, 21. Note that the size D of the projections and recesses of the fine concave-convex structure 20 may be the arithmetic mean value (average size) of the planar shapes of the multiple convex portions 21 (or recesses 22) constituting the fine concave-convex structure 20. For example, the planar shapes of the multiple convex portions 21 constituting the fine concave-convex structure 20 can be measured, and the arithmetic mean value (average size) of these measurements can be calculated as the size D.

[0064] The arrangement of the concave-convex pattern of the micro concave-convex structure 20 on the surface (XY plane) of the optical film 1 according to this embodiment will now be described in more detail with reference to Fig. 4. In Fig. 4, the X direction corresponds to the longitudinal direction of the optical film 1, the Y direction corresponds to the width direction of the optical film 1, and the Z direction corresponds to the thickness direction of the optical film 1.

[0065] As shown in Fig. 4, a plurality of convex portions 21 of the microrelief structure 20 are arranged in a hexagonal lattice pattern on the surface of the optical film 1 according to this embodiment. In the hexagonal lattice pattern, the plurality of convex portions 21 are arranged at the vertices of a hexagonal lattice on the XY plane. In the example of Fig. 4, the planar shape of the convex portions 21 is circular, but it may be other shapes such as elliptical.

[0066] Here, the plurality of protrusions 21 are arranged along a plurality of tracks T that are parallel to one another. In other words, the plurality of protrusions 21 are arranged along a plurality of rows of tracks T on the surface of the optical film 1.

[0067] The tracks T are imaginary straight lines extending in a predetermined first direction on the XY plane of the optical film 1, and indicate the arrangement direction of the concavo-convex pattern of the fine concavo-convex structure 20. A plurality of tracks T are arranged at predetermined intervals (track pitch P) in a second direction perpendicular to the first direction. T ) are spaced apart. Here, the first direction is the direction in which the tracks T extend (hereinafter referred to as the "track extension direction"). The second direction is the direction in which the tracks T are arranged (hereinafter referred to as the "track pitch direction"), and is a direction perpendicular to the first direction. For example, as shown in FIG. 4, the first direction (track extension direction) may be the longitudinal direction (X direction) of the optical film 1, and the second direction (track pitch direction) may be, for example, the width direction (Y direction) of the optical film 1. However, the present invention is not limited to this example, and the track extension direction may be any direction other than the longitudinal direction (X direction) of the optical film 1.

[0068] Here, as shown in FIG. 4, the dot pitch P D is the pitch (period) of the plurality of convex portions 21 arranged along the track T in the track extension direction (X direction). T is the mutual interval between a plurality of tracks T, T adjacent to each other in the track pitch direction (Y direction).

[0069] Dot Pitch P D and track pitch P TSimilarly to the pitch P described above, is equal to or less than the wavelength of the visible light band, for example, 350 nm or less, preferably 250 nm or less, and may be, for example, about 200 nm. D , P T is, for example, 100 nm or more, preferably 120 nm or more, and more preferably 130 nm or more, whereby the fine uneven structure 20 can function as a so-called moth-eye structure that suppresses reflection of incident light in a wide wavelength band.

[0070] Dot Pitch P D and track pitch P T The dot pitch P D Track pitch P T (P D >P T ). For example, P D = 230 nm, P T = 150 nm.

[0071] In addition, in the hexagonal lattice arrangement of the fine uneven structure 20 shown in FIG. 4, the convex portions 21 are arranged at half pitch (½P) in the X direction between the tracks T, T adjacent to each other in the Y direction. D ) are arranged at positions shifted by half a period (180°). That is, between tracks T, T adjacent to each other in the Y direction, the phases of the convex portions 21 arranged in the X direction are shifted by half a period (180°). Specifically, between two adjacent tracks T, T, the convex portions 21 arranged on one track T are arranged at the midpoint in the X direction (positions shifted by half a pitch) of the convex portions 21 arranged on the other track T. As a result, as shown in FIG. 4, the multiple convex portions 21 are arranged in a hexagonal lattice pattern on three adjacent tracks T.

[0072] In this way, the arrangement of the convex portions 21 is set to a half pitch (1 / 2P) for each track T. D) the plurality of protrusions 21 can be arranged in a close-packed hexagonal lattice pattern on the XY plane. This maximizes the proportion of the area occupied by the plurality of protrusions 21 on the XY plane (the packing rate of the protrusions 21), thereby improving the anti-reflection function per unit area.

[0073] The arrangement of the projections and recesses of the micro uneven structure 20 is not limited to the above-mentioned hexagonal lattice example, and may be other arrangements. For example, the arrangement of the projections and recesses of the micro uneven structure 20 may be a square lattice arrangement in which the projections 21 are arranged at the vertices of a square lattice, a rectangular lattice arrangement, or another lattice arrangement. However, in order to pack the projections 21 closest in density on the XY plane, a hexagonal lattice arrangement is preferable.

[0074] Furthermore, the shape of the track T is not limited to the linear track T example described above, and for example, curved tracks such as arc-shaped tracks may be arranged concentrically. Furthermore, the track T having these shapes may be made to wobble (meander). By making the track T wobble in this way, it is possible to suppress the occurrence of unevenness in appearance.

[0075] [1.4. Configuration of the convex portion of the line marker area] Next, the convex streak portion 31 formed in the line marker region 3 (visible region) of the optical film 1 according to this embodiment will be described in more detail with reference to FIGS.

[0076] 2 and 3, a plurality of ridges 31 are formed in the band-shaped line marker region 3 on the surface of the resin layer 12 of the optical film 1. The ridges 31 are arranged at a track pitch P that is equal to or greater than the wavelength of visible light (for example, 500 nm or greater). t The protruding ridges 31 according to this embodiment are linear protruding ridges extending along the longitudinal direction (X direction) of the band-shaped line marker region 3. The linear protruding ridges 31 are arranged in parallel and spaced apart in the width direction (Y direction) of the line marker region 3.

[0077] In the line marker region 3, flat portions 32 parallel to the surface of the substrate 11 are formed between adjacent convex streak portions 31. The planar shape of the flat portions 32 is a strip extending along the longitudinal direction (X direction) of the line marker region 3. The convex streak portions 31 and the flat portions 32 are alternately arranged in the width direction (Y direction) of the line marker region 3. Note that the region between adjacent convex streak portions 31 does not necessarily have to be a flat portion 32, and may have, for example, unevenness such as the uneven pattern (nanometer size) of the fine uneven structure 20 described above.

[0078] The cross-sectional shape of the convex rib portion 31 (cross-section in the YZ plane) may be any shape as long as it is a shape that protrudes in a direction intersecting the surface of the base material 11. In the examples of Figures 2 and 3, the cross-sectional shape of the convex rib portion 31 is, for example, a bell shape having a convex curved surface at the top, which is the same shape as the convex portion 21 of the above-mentioned fine concave-convex structure 20, but is not limited to such an example.

[0079] The cross-sectional shape of the convex rib portion 31 may be various convex shapes, such as a cut cone shape (e.g., a bell shape, an elliptical truncated cone shape), a semicircular shape, a semi-elliptical shape, or a substantially triangular shape. Examples of cone shapes include a cone shape with a pointed apex, a cone shape with a flat apex, and a cone shape with a convex or concave curved surface at the apex. Examples of cone shapes with a convex curved surface at the apex include quadratic curved surfaces such as a paraboloid. In addition, the cone surface of the cone shape may be curved in a concave or convex shape.

[0080] The cross-sectional shape of the ridges 31 is not limited to the shapes exemplified above. The semicircular, semielliptical, conical, and other shapes mentioned above include not only mathematically defined perfect semicircles, semiellipses, cones, and other shapes, but also semicircular, semielliptical, conical, and other shapes that are slightly distorted. The multiple ridges 31 have the same size, shape, and height h. However, the configuration of the ridges 31 is not limited to this, and ridges 31 having two or more different sizes, shapes, and heights h may be formed on the surface of the resin layer 12.

[0081] The convex stripes 31 have a track pitch P that is equal to or greater than the wavelength of visible light. t Here, the track of the ridge portion 31 is a virtual center line along the extension direction of each ridge portion 31. The track pitch P of the ridge portion 31 is t is the distance (center-to-center distance) between the adjacent convex stripes 31. t means the period of the periodic structure of the ridge portion 31.

[0082] The track pitch P of the ridge portion 31 t may be the arithmetic mean value (average pitch, average period) of the pitch of the plurality of convex rib portions 31. For example, a plurality of combinations of adjacent convex rib portions 31, 31 are picked up, the center-to-center distance between the convex rib portions 31, 31 of each combination is measured, and the arithmetic mean value (average pitch, average period) of these measurements is calculated as the track pitch P. t It can be calculated as:

[0083] The convex stripe portion 31 according to this embodiment has a track pitch P t The track pitch P of the ridges 31 is t is preferably 500 nm or more and 1 mm or less, more preferably 1 μm or more and 10 μm or less, and may be, for example, about 1 μm. t If the track pitch P is 500 nm or more and 1 mm or less, the arrangement pitch of the plurality of convex ridge portions 31 is within an appropriate range of the order of microns, and therefore the plurality of convex ridge portions 31 function suitably as a diffraction grating. t If the pitch is 1 μm or more and 10 μm or less, the arrangement pitch of the plurality of ridge portions 31 will be in a more appropriate range of the order of microns, and the plurality of ridge portions 31 will function more suitably as a diffraction grating.

[0084] The width w of the ridge portion 31 is the width of the ridge portion 31 in the direction (Y direction) perpendicular to the direction in which the ridge portion 31 extends (X direction). There are no particular restrictions on the width w of the ridge portion 31, but it may be equivalent to the size D (dot size) of the irregularities of the fine uneven structure 20, for example, about 200 nm. The width w of the ridge portion 31 may be the arithmetic mean value (average height) of the widths of multiple ridge portions 31. For example, the widths of multiple ridge portions 31 can be measured individually, and the arithmetic mean value (average width) of these measured values ​​can be calculated as the width h.

[0085] The height h of the ridge portions 31 is the protruding height of the ridge portions 31 from the surface of the resin layer 12 (the reference plane of the flat portion 32). There are no particular restrictions on the height h of the ridge portions 31, but it is, for example, 100 nm or more and 400 nm or less, preferably 150 nm or more and 300 nm or less, and more preferably 200 nm or more and 300 nm or less. The height h of the ridge portions 31 may be the arithmetic mean value (average height) of the heights of the multiple ridge portions 31. For example, the heights of the multiple ridge portions 31 can be measured individually, and the arithmetic mean value (average height) of these measured values ​​can be calculated as the height h.

[0086] It is preferable that the height h of the convex streak portion 31 is substantially the same as the height H of the convex portions 21 of the fine concave-convex structure 20. Here, "the height h and the height H being substantially the same" means that the difference between one height and the other is within a range of ±30%, preferably within a range of ±10%, and more preferably within a range of ±5%. If the height h and the height H are substantially the same, no difference in height occurs between the convex streak portion 31 in the line marker region 3 and the convex portions 21 of the fine concave-convex structure 20 in the concave-convex pattern region 2. This has the effect of making it less likely for winding distortion to occur when the optical film 1 is wound into a film roll.

[0087] The aspect ratio of the ridge portion 31 (height h / arrangement pitch P t ) is preferably 1.96 or less. When the aspect ratio of the ridge portions 31 is 1.96 or less, the releasability when the ridge portions 31 are peeled off from the roll master can be improved.

[0088] The above has described the configuration of the multiple convex ridge portions 31 provided in the line marker region 3 according to this embodiment. Due to the periodic structure of the multiple convex ridge portions 31 in the line marker region 3, incident light on the line marker region 3 is diffracted and interfered with, so that visible light (rainbow light) separated into wavelengths is emitted from the line marker region 3.

[0089] In detail, the periodic structure of the plurality of ridges 31 in the line marker region 3 functions as a diffraction grating. Generally, a diffraction grating refers to a structure in which linear projections and recesses are arranged side by side at a period (pitch) on the order of micrometers. In the line marker region 3 according to this embodiment, the plurality of linear projections 31 are arranged at a track pitch P on the order of micrometers. t A pattern (one-dimensional periodic pattern) is formed in which the electrodes are arranged in parallel.

[0090] The one-dimensional pattern of the ridge portions 31 in the line marker region 3 functions as a diffraction grating. That is, when light containing a mixture of multiple colors (wavelengths), such as sunlight, fluorescent light, or LED lamp light, enters the line marker region 3, the incident light is diffracted and interferes with the diffraction grating made up of the ridge portions 31. Here, diffraction and interference occur due to the diffraction grating made up of the ridge portions 31, regardless of whether the light is transmitted through the line marker region 3 or reflected light from the line marker region 3. Due to this diffraction and interference, the light incident on the line marker region 3 is split into separate colors (wavelengths) and emitted diffused in different directions. As a result, the light emitted from the line marker region 3 becomes rainbow-colored diffused light that is visible to the user of the optical film 1.

[0091] In this embodiment, a diffraction grating having a one-dimensional periodic pattern in which linear ridges 31 are arranged in parallel is used, but the ridges of the present invention are not limited to this example. For example, a pattern in which multiple ridges are arranged two-dimensionally (two-dimensional periodic pattern), such as a pattern in which curved ridges are arranged concentrically, may be used as the diffraction grating.

[0092] More specifically, the convex ridge portion 31 according to this embodiment is linear and extends in a direction parallel to the longitudinal direction (X direction) of the line marker area 3. However, the shape of the convex ridge portion of the present invention is not limited to this example. A plurality of convex ridge portions are arranged at a track pitch P of micrometer size. t If the plurality of protrusions are arranged at a distance from one another, the assembly of the plurality of protrusions can function as a diffraction grating for visible light. Therefore, the extension direction and shape of the protrusions are not limited to the examples shown in FIGS. 2 and 3. For example, the protrusions may be in various forms of lines, such as straight lines, dashed lines, dotted lines, wavy lines, zigzags, etc., extending not only in the longitudinal direction (X direction) of the line marker region 3 but also in a direction intersecting the longitudinal direction or in any other direction. For example, the protrusions do not have to be continuous straight lines, but may be discontinuous dashed lines, dotted lines, etc. Furthermore, the protrusions may be curved, such as in an arc shape, or may be arranged concentrically.

[0093] Furthermore, in this embodiment, the concave-convex pattern region 2 where the fine concave-convex structure 20 is formed and the line marker region 3 where the convex streak portion 31 is formed are separated on the surface of the optical film 1 without overlapping each other. However, this is not limited to such an example, and for example, the concave-convex pattern region 2 and the line marker region 3 may overlap each other, or the convex streak portion 31 may be formed by overlapping on the fine concave-convex structure 20. Even in such an overlapping structure, the track pitch P on the order of micrometers may be set. t The ridges 31 arranged in this manner function as a diffraction grating, so that visible rainbow light can be generated.

[0094] As described above, in this embodiment, the line marker region 3 provided with the ridges 31 functioning as a diffraction grating serves as a visible region that emits rainbow-colored diffused light. Therefore, by visually recognizing the rainbow-colored diffused light from the line marker region 3, a user can easily recognize the presence, position, size, orientation, and the like of the optical film 1. This improves visibility with the naked eye when handling a product using the optical film 1, thereby improving user convenience.

[0095] [2. Structure of the roll master] [2.1. Overall structure of roll master] Next, the configuration of the roll master 100 used to produce the optical film 1 according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a perspective view schematically showing the roll master 100 according to this embodiment.

[0096] As shown in FIG. 5, the roll master 100 according to this embodiment includes a master substrate 110 and a concave-convex pattern (fine concave-convex structure 120, spiral groove 131) formed on the outer peripheral surface of the master substrate 110.

[0097] The roll master 100 according to this embodiment is a master used in, for example, a roll-to-roll imprinting technique. In the roll-to-roll imprinting technique, the outer peripheral surface of the roll master 100 is pressed against a strip-shaped optical film while the roll master 100 is rotating, thereby transferring the concave-convex pattern formed on the outer peripheral surface of the roll master 100 to the surface of the optical film. By using such an imprinting technique, it is possible to efficiently manufacture a large-area optical film to which the concave-convex pattern formed on the outer peripheral surface of the roll master 100 has been transferred.

[0098] The optical film onto which the concave-convex pattern is transferred by the roll master 100 is used as the optical film 1 applicable to shielding members such as the face shield and eye shield. However, the optical film is not limited to such examples, and may be used as various optical members such as antireflection films for other purposes, surface plasmon filters, or light-emitting devices.

[0099] The roll master 100 according to this embodiment is a roll-shaped master having a cylindrical or columnar shape. The outer peripheral surface of the roll master 100 serves as a molding surface for molding a concave-convex structure on the surface of the optical film. A concave-convex pattern to be a transfer pattern is arranged two-dimensionally on the outer peripheral surface of this roll master 100. The concave-convex pattern arranged on the outer peripheral surface of the roll master 100 and the concave-convex pattern arranged on the surface of the optical film 1 described above have an inverted concave-convex relationship. In other words, the shape, arrangement, arrangement pitch, etc. of the concave-convex pattern of the roll master 100 are the same as those of the concave-convex pattern of the optical film 1.

[0100] The master substrate 110 is, for example, a cylindrical or columnar member as shown in Fig. 5. The concave-convex pattern to be transferred is formed on the outer peripheral surface of the master substrate 110. The master substrate 110 may be made of a glass material such as fused silica glass or synthetic silica glass, or may be made of a metal such as stainless steel, or a metal whose outer peripheral surface is coated with SiO2 or the like.

[0101] However, it is preferable that at least the outer peripheral surface of the master substrate 110 is formed of a glass material such as quartz glass. Furthermore, it is more preferable that the entire master substrate 110 is formed of a glass material such as quartz glass. The reason for this is that by forming the master substrate 110 from a glass material mainly composed of SiO2, a fine concave-convex pattern can be easily formed on the outer peripheral surface of the master substrate 110 by etching with a fluorine compound. Specifically, a concave-convex pattern is formed on a resist layer provided on the outer peripheral surface of the master substrate 110 using laser lithography. Thereafter, the concave-convex pattern of the resist layer is used as a mask to dry-etch the outer peripheral surface of the master substrate 110, thereby easily forming a concave-convex pattern on the outer peripheral surface of the master substrate 110. The master substrate 110 formed of a glass material is, for example, a transparent roll type.

[0102] The size of the master substrate 110 is not particularly limited, but the axial length (roll width) of the master substrate 110 may be, for example, 100 mm or more, and the outer diameter of the master substrate 110 may be, for example, 50 mm or more and 300 mm or less. Furthermore, when the master substrate 110 has a cylindrical shape, the thickness of the cylinder may be, for example, 2 mm or more and 50 mm or less.

[0103] As shown in FIG. 5, a concave-convex pattern area 102 (corresponding to the "master concave-convex pattern area") and a line marker area 103 (corresponding to the "master line marker area") are provided on the outer peripheral surface of the master substrate 110 according to this embodiment.

[0104] The concave-convex pattern region 102 is a cylindrical curved region provided around the entire circumference of the roll master 100 in the circumferential direction (hereinafter also referred to as the "roll circumferential direction"), and occupies most of the outer circumferential surface of the master substrate 110. The line marker region 103 is an annular curved region provided in a band shape around the entire circumference in the roll circumferential direction. In the example of FIG. 5, line marker regions 103, 103 are arranged at both ends of the width direction (hereinafter also referred to as the "roll width direction") of the roll master 100. These line marker regions 103, 103 are arranged adjacent to the concave-convex pattern region 102 on both sides in the roll width direction. The line marker regions 103, 103 are arranged inward a predetermined distance from both ends of the roll master 100 in the roll width direction.

[0105] The width and area of ​​the concave-convex pattern region 102 are significantly larger than the width and area of ​​the line marker region 103. For example, the width of the concave-convex pattern region 102 in the roll width direction may be about several hundred mm (e.g., 500 mm), and the width of the line marker region 103 in the roll width direction may be about several mm (e.g., 2 mm).

[0106] The concave-convex pattern region 102 and the line marker region 103 of the roll master 100 correspond to the concave-convex pattern region 2 (anti-reflection region) and the line marker region 3 (visible region) of the optical film 1 described above, respectively.

[0107] [2.2. Configuration of the fine concave-convex structure in the concave-convex pattern area] Next, with reference to FIG. 5, the fine concave-convex structure 120 formed in the concave-convex pattern region 102 on the outer circumferential surface of the roll master 100 according to this embodiment will be described in detail.

[0108] A fine concave-convex structure 120 (corresponding to the "master fine concave-convex structure") is formed as a transfer pattern in the concave-convex pattern region 102 of the roll master 100. The fine concave-convex structure 120 in the concave-convex pattern region 102 of the roll master 100 has an inverted shape of the fine concave-convex structure 20 in the concave-convex pattern region 2 of the optical film 1. In other words, the recesses 121 and the protrusions 122 of the fine concave-convex structure 120 of the roll master 100 have inverted shapes corresponding to the protrusions 21 and the recesses 22 of the fine concave-convex structure 20 of the optical film 1, respectively.

[0109] 5, a plurality of recesses 121 each having a circular planar shape are formed in the recessed / protruding pattern region 102 of the roll master 100. These recesses 121 are arranged in a hexagonal lattice pattern on the outer peripheral surface of the master substrate 110. The protrusions 122 are protruding portions provided between adjacent recesses 121, 121.

[0110] The microrelief structure 120 will be described in more detail. On the outer peripheral surface of the roll master 100 according to this embodiment, the multiple recesses 121 of the microrelief structure 120 are arranged in a hexagonal lattice pattern at a pitch P' that is equal to or less than the wavelength of visible light. The pitch P' of the recesses 121 of the microrelief structure 120 is the same as the pitch P of the protrusions 21 of the microrelief structure 20 of the optical film 1 described above. The pitch P' is equal to or less than the wavelength of visible light, and may be, for example, 350 nm or less, preferably 250 nm or less, and may be, for example, about 200 nm.

[0111] Here, similar to the hexagonal lattice arrangement of the convex portions 21 of the fine concave-convex structure 20 described above (see FIG. 4), the concave portions 121 of the fine concave-convex structure 120 of the roll master 100 are also arranged along a plurality of tracks T' that are parallel to one another, as shown in the enlarged view of FIG. 5. The plurality of tracks T' are arranged at predetermined intervals (track pitch P) in a second direction (track pitch direction) perpendicular to the first direction (track extension direction). T For example, as shown in FIG. 5, the first direction (track extension direction) may be the roll circumferential direction, and the second direction may be the roll width direction.

[0112] Here, the dot pitch P D The track pitch P' is the pitch (period) of the plurality of recesses 121 arranged in the first direction (for example, the roll circumferential direction) along the track T'. T The dot pitch P of the recesses 121 of the fine concave-convex structure 120 is the distance between the tracks T' arranged adjacent to each other in the second direction (for example, the roll width direction). D ', Track Pitch P T ' are the dot pitch P of the convex portions 21 of the fine concave-convex structure 20 of the optical film 1 described above. D , track pitch P T For example, the dot pitch P D ' may be 230 nm, and the track pitch P T ' may be 150 nm.

[0113] In the hexagonal lattice arrangement of the fine uneven structure 120 shown in FIG. 5, the recesses 121 are arranged at half pitch (½P) in the circumferential direction of the roll between the tracks T′, T′ adjacent in the width direction of the roll. D That is, between the tracks T, T adjacent in the roll width direction, the phases of the recesses 121 arranged in the roll circumferential direction are shifted by half a period (180°).

[0114] In this way, the arrangement of the recesses 121 is changed to a half pitch (1 / 2P) for each track T' (i.e., for each rotation of the roll). DBy shifting the recesses 121 from each other, the recesses 121 can be arranged in a close-packed hexagonal lattice pattern on the outer peripheral surface of the roll master 100. This maximizes the ratio of the area occupied by the recesses 121 of the fine concave-convex structure 120 on the outer peripheral surface (the filling rate of the recesses 121). This improves the anti-reflection function per unit area of ​​the optical film 1 to which the fine concave-convex structure 120 has been transferred.

[0115] Note that various dimensions such as the depth H', size D' (dot size), aspect ratio (depth H' / arrangement pitch P') of the recesses 121 of the fine concave-convex structure 120 are the same as the height H, size D (dot size), aspect ratio (height H / arrangement pitch P) of the protrusions 21 of the fine concave-convex structure 20 of the optical film 1 described above. Therefore, detailed description of these dimensions will be omitted.

[0116] The above has described the fine concave-convex structure 120 formed in the concave-convex pattern region 102 of the roll master 100. By transferring the fine concave-convex structure 120 of the roll master 100 to the optical film 1, the above-mentioned fine concave-convex structure 20 (see FIGS. 2 to 4) can be suitably formed in the concave-convex pattern region 2 of the optical film 1.

[0117] [2.3. Groove configuration in the line marker area] Next, with reference to FIG. 5, the spiral groove 131 formed in the line marker region 103 on the outer circumferential surface of the roll master 100 according to this embodiment will be described in detail.

[0118] A spiral groove 131 (spiral groove) is formed around the entire circumference of the roll in the line marker region 103 of the roll master 100. This spiral groove 131 is formed continuously or discontinuously so as to wrap around the outer circumferential surface of the roll master 100 over multiple revolutions (for example, several hundred to several thousand revolutions).

[0119] Here, the grooves 131 are formed on the outer peripheral surface of the roll master 100 at a track pitch P tThe track T' of the groove 131 is a virtual center line of one revolution of the spiral groove 131 that wraps around the outer circumferential surface of the roll master 100 over multiple revolutions, as shown in FIG. 5. The track pitch P of the groove 131 is t The track pitch P' is the distance (center-to-center distance) between two tracks T', T' adjacent to each other in the roll width direction among the spiral grooves 131 formed on the outer peripheral surface of the roll master 100. t The period of the periodic structure of the spiral grooves 131 formed on the outer peripheral surface of the roll master 100 is represented by the track pitch P t The track pitch P' is calculated by picking up a plurality of combinations of two adjacent tracks T', T' in the groove 131 in the roll width direction, measuring the distance (center-to-center distance) between each combination, and calculating the arithmetic mean value (average pitch, average period) of these measurements. t It may be calculated as '.

[0120] The track pitch P of the spiral groove 131 t ' is the track pitch P of the convex stripe portion 31 of the optical film 1 described above. t and is set to an appropriate value in micrometers. For example, the track pitch P t The track pitch P' is preferably 500 nm or more and 1 mm or less, more preferably 1 μm or more and 10 μm or less, and may be, for example, about 1 μm. t Since the distance ' falls within an appropriate range on the order of microns, the convex ridges 31 of the optical film 1 formed by transferring the grooves 131 of the roll master 100 function suitably as a diffraction grating.

[0121] The grooves 131 in this line marker region 103 have an inverted shape of the convex streak portions 31 in the line marker region 3 of the optical film 1 described above. In other words, the cross-sectional shape of the grooves 131 is an inverted shape of the cross-sectional shape of the convex streak portions 31. The cross-sectional shape of the grooves 131 may be various convex shapes, such as a cut cone shape (a bell shape, an elliptical truncated cone shape, etc.), a semicircular shape, a semi-elliptical shape, or a substantially triangular shape. Examples of cone shapes include a cone shape with a pointed apex, a cone shape with a flat apex, and a cone shape with a convex or concave curved surface at the apex. Examples of cone shapes with a convex curved surface at the apex include a quadratic curved surface such as a paraboloid. Furthermore, the cone surface of the cone shape may be curved concavely or convexly.

[0122] The width w' of the groove 131 is the same as the width w of the protruding streak portion 31. For example, the width w' of the groove 131 may be equivalent to the size D' (dot size) of the recessed portion 121 of the fine uneven structure 120 described above, and may be about 200 nm.

[0123] The depth h' of the groove 131 is the same as the height h of the protruding streak portion 31. For example, the depth h' of the groove 131 may be equal to the depth H' of the recess 121 of the microrelief structure 120 described above, and is, for example, 100 nm or more and 400 nm or less, preferably 150 nm or more and 300 nm or less, and more preferably 200 nm or more and 300 nm or less.

[0124] The above has described the spiral grooves 131 formed in the line marker region 103 of the roll master 100. By transferring the spiral grooves 131 of the roll master 100 to the optical film 1, the above-mentioned multiple convex streak portions 31 (see FIGS. 2 and 3) can be suitably formed in the line marker region 3 of the optical film 1. As a result, the convex streak portions 31 function as a diffraction grating and diffuse rainbow-colored light from the line marker region 3, making the line marker region 3 a visible region and improving the handleability of the optical film 1.

[0125] [3. Configuration of exposure equipment] Next, the configuration of an exposure device 200 used in manufacturing the roll master 100 according to this embodiment will be described with reference to Fig. 6. Fig. 6 is a block diagram showing the configuration of the exposure device 200 used in manufacturing the roll master 100 according to this embodiment.

[0126] As shown in FIG. 6, the exposure apparatus 200 includes a laser light source 201, a first mirror 203, a photodiode (PD) 205, a condenser lens 207, an electro-optic deflector (EOD) 209, a collimator lens 211, a second mirror 213, a movable optical table 220, a spindle motor 225, a turntable 227, and a control device 230.

[0127] The laser light source 201 is a light source that emits laser light 202 for exposing the roll master 100. The laser light source 201 may be, for example, a semiconductor laser light source that emits laser light with a wavelength of 400 nm to 500 nm in the blue light band. The laser light source 201 is controlled by a control device 230.

[0128] Laser light 202 emitted from laser light source 201 travels straight as a parallel beam and is reflected by first mirror 203. First mirror 203 is made up of a polarizing beam splitter, and has the function of reflecting one polarized component and transmitting the other polarized component. The polarized component that has transmitted through first mirror 203 is photoelectrically converted by photodiode 205. The photoelectrically converted received light signal is input to laser light source 201. This allows laser light source 201 to adjust the output of laser light 202 based on feedback from the input received light signal.

[0129] The laser beam 202 reflected by the first mirror 203 is guided to the deflection optical system, which includes a condenser lens 207, an electro-optical deflector element 209, and a collimator lens 211.

[0130] In the deflection optical system, the laser beam 202 is focused onto an electro-optical deflector 209 by a condenser lens 207. The electro-optical deflector 209 is an element that can control the irradiation position of the laser beam 202 at a distance of about nanometers. The electro-optical deflector 209 makes it possible to finely adjust the irradiation position of the laser beam 202 on the master substrate 110. After the irradiation position of the laser beam 202 is adjusted by the electro-optical deflector 209, the laser beam 202 is collimated again by a collimator lens 211. The collimated laser beam 202 is reflected by a second mirror 213 and directed horizontally onto a movable optical table 220.

[0131] The moving optical table 220 includes a beam expander (BEX) 221 and an objective lens 223. The roll master 100 is placed on a turntable 227. The turntable 227 is a table that supports the roll master 100 and can be rotated by a spindle motor 225.

[0132] The beam expander 221 shapes the laser beam 202 guided by the second mirror 213 into a desired beam shape. The shaped laser beam 202 passes through an objective lens 223 and is irradiated onto a resist layer formed on the outer peripheral surface of the master substrate 110 of the roll master 100.

[0133] When the master substrate 110 of the roll master 100 is irradiated with the laser beam 202, the spindle motor 225 rotates the turntable 227 and the master substrate 110, while the movable optical table 220 moves the irradiation position of the laser beam 202 in the axial direction (roll width direction) of the roll master 100. For example, every time the master substrate 110 rotates once, the movable optical table 220 moves the irradiation position of the laser beam 202 by one feed pitch (track pitch) in the direction of arrow R (feed pitch direction). This allows the laser beam 202 to be spirally irradiated onto the outer peripheral surface of the master substrate 110, thereby exposing the resist layer on the outer peripheral surface of the master substrate 110 along a spiral scanning trajectory. The irradiation position of the laser beam 202 may be moved by moving either the laser head including the laser light source 201 or the turntable 227 supporting the roll master 100 along a slider.

[0134] The control device 230 also controls the emission of the laser beam 202 from the laser light source 201, thereby controlling the irradiation time and irradiation position of the laser beam 202. The control device 230 generates an exposure signal that controls the emission of the laser beam 202. The control device 230 may have, for example, a function generator including a signal generation circuit that can generate a signal of an arbitrary waveform. The control device 230 includes a formatter 231 and a driver 233.

[0135] The formatter 231 generates an exposure signal for controlling the emission of the laser beam 202 from the reference clock signal. The exposure signal is a signal representing the concave-convex pattern to be formed on the outer peripheral surface of the roll master 100. The driver 233 controls the emission of the laser beam 202 from the laser beam source 201 based on the exposure signal generated by the formatter 231. For example, the driver 233 may control the laser beam source 201 so that the laser beam 202 is emitted when the exposure signal consisting of a rectangular pulse wave is at a high level. The spindle motor 225 rotates the turntable 227 based on a rotation control signal generated from the reference clock signal. For example, the spindle motor 225 may control the rotation of the turntable 227 so that the turntable 227 rotates once during a period in which a predetermined number of pulses of the rotation control signal are input.

[0136] As described above, the laser light source 201 is controlled by an exposure signal generated by the control device 230, and the laser light 202 emitted from the laser light source 201 is irradiated onto the roll master 100 placed on the turntable 227. Furthermore, the spindle motor 225 rotates the turntable 227 on which the roll master 100 is placed, based on the rotation control signal. Here, the exposure signal and the rotation control signal may be generated from a common reference clock signal and may be synchronized with each other.

[0137] The above has described an example of the configuration of the exposure apparatus 200 according to this embodiment. The exposure apparatus 200 according to this embodiment can expose the outer peripheral surface of the master substrate 110 of the roll master 100 to light, thereby precisely forming an exposure pattern (concave-convex pattern) of a desired shape.

[0138] [4. Exposure method] Next, an exposure method for exposing the outer peripheral surface of the master substrate 110 of the roll master 100 using the exposure device 200 will be described with reference to Fig. 7. Fig. 7 is a schematic diagram illustrating an exposure method for the roll master 100 according to this embodiment.

[0139] 7, in the exposure method for the roll master 100 according to this embodiment, an exposure pattern is formed by irradiating the outer peripheral surface of the master substrate 110 with laser light 202 using the exposure device 200 described above. As described above, the exposure device 200 includes a laser light source 201 that emits the laser light 202 and a control device 230 that controls the emission of the laser light 202.

[0140] In the exposure step, while rotating the master substrate 110 of the roll master 100 around the roll axis and moving the laser light source 201 of the exposure device 200 in the roll width direction (the direction of arrow R in FIG. 7), the outer peripheral surface of the master substrate 110 is irradiated with laser light 202. As a result, the outer peripheral surface of the master substrate 110 is irradiated with the laser light 202 in a spiral pattern, and an exposure pattern of a desired shape can be formed in a desired region of the outer peripheral surface of the master substrate 110.

[0141] An exposure pattern corresponding to the fine uneven structure 120 is formed in the uneven pattern region 102 on the outer peripheral surface of the master substrate 110. On the other hand, an exposure pattern corresponding to the spiral groove 131 is formed in the line marker region 103. The example of Fig. 7 shows a state in which an exposure pattern corresponding to the fine uneven structure 120 is formed by irradiating the uneven pattern region 102 with laser light 202 along a spiral irradiation locus. It should be noted that the order in which the exposure patterns of the fine uneven structure 120 and the spiral groove 131 are formed is not particularly important.

[0142] Here, referring to Fig. 8, a specific description will be given of the correspondence between the exposure signal used by the exposure apparatus 200 according to this embodiment and the exposure pattern formed on the outer peripheral surface of the master substrate 110. Fig. 8 is an explanatory diagram showing the correspondence between the exposure signal and the exposure pattern according to this embodiment.

[0143] As shown in Fig. 8, in this embodiment, an exposure pattern in which circular dot patterns are arranged in a hexagonal lattice pattern is formed on the outer peripheral surface of the master substrate 110 by irradiating the laser beam 202 along a spiral irradiation locus. In this exposure pattern, circular dot patterns corresponding to the recesses 121 of the fine concave-convex structure 120 are arranged in a hexagonal lattice pattern. These circular dot patterns are arranged at a predetermined track pitch P T The dots are arranged along a plurality of rows of tracks T' arranged in a line. The planar shape of the dot pattern is not limited to the circular example shown in FIG. 8, but may be, for example, an elliptical or oblong shape having a major axis in the extension direction of the tracks T'.

[0144] The exposure apparatus 200 according to this embodiment uses, as the exposure signal, for example, a pulse wave signal that alternates between high and low levels at a predetermined cycle in order to form an exposure pattern consisting of a plurality of dot patterns arranged along the track T'. The exposure apparatus 200 controls the irradiation of the laser light 202 so that a circular dot pattern is formed on the outer peripheral surface of the master substrate 110 when the exposure signal is at a high level.

[0145] Furthermore, to form an exposure pattern in which the dot pattern is arranged in a hexagonal lattice pattern as shown in FIG. 8, the frequency of the exposure signal is set so that the exposure signal is shifted by 1 / 2 pulse between tracks T', T' adjacent to each other in the roll width direction of the master substrate 110. In other words, while maintaining the continuity of the exposure signal, the phase of the exposure signal is inverted by 180° for each revolution of the spiral laser irradiation locus (i.e., for each track T'). As a result, the position of the dot pattern is shifted by 0.5 pitches in the roll circumferential direction for each revolution of the spirally arranged dot pattern in the roll circumferential direction (i.e., for each track T'). In this way, an exposure pattern in which the dot pattern is precisely arranged in a hexagonal lattice pattern can be formed on the outer peripheral surface of the master substrate 110 using the spiral laser irradiation locus.

[0146] Incidentally, when the laser beam 202 is irradiated along a spiral irradiation locus as described above, the length of one circumference of the master substrate 110 may vary from circumference to circumference due to processing errors in the master substrate 110. Therefore, if the exposure signal and the rotation control signal are not synchronized, the arrangement of the exposure pattern will be disrupted as the exposure progresses. Furthermore, the spindle motor 225 of the turntable 227 that rotates the master substrate 110 has fluctuations in rotation speed, and the fluctuations in rotation speed will disrupt the arrangement of the exposure pattern.

[0147] Therefore, in this embodiment, the exposure signal and the rotation control signal are synchronized by sharing a reference clock on which they are based. This allows the frequency of the exposure signal to be set to any value, without being limited by dividing or multiplying the rotation control signal. Therefore, it is possible to continuously form a desired exposure pattern on the outer peripheral surface of the master substrate 110 while maintaining the continuity of the exposure signal. Therefore, in the exposure pattern of the fine uneven structure 120, in which multiple dot patterns are arranged in a hexagonal lattice pattern, interruptions in the exposure pattern and disruptions in the arrangement can be prevented, and the exposure pattern can be continuously formed with high precision.

[0148] 8, an example has been described in which a hexagonal lattice-shaped exposure pattern corresponding to the fine uneven structure 120 is formed in the uneven pattern region 102 on the outer peripheral surface of the master substrate 110. On the other hand, when an exposure pattern corresponding to the spiral groove 131 is formed in the line marker region 103, the exposure device 200 irradiates the line marker region 103 with laser light in a spiral irradiation locus. At this time, the track pitch P of the spiral groove 131 is t The scanning speed of the laser light 202 in the roll width direction (movement speed of the laser light source 201) and the rotation speed of the master substrate 110 are controlled so that the width w' and depth h' of the spiral groove 131 become the desired dimensions. In addition, the irradiation spot diameter, irradiation intensity, etc. of the laser light 202 are controlled so that the width w' and depth h' of the spiral groove 131 become the desired dimensions.

[0149] As described above, according to this embodiment, by using the same exposure device 200 and a similar laser irradiation method, it is possible to form exposure patterns corresponding to both the fine concave-convex structure 120 in the concave-convex pattern area 102 and the spiral groove 131 in the line marker area 103 on the outer peripheral surface of the roll master 100. Therefore, both exposure patterns can be easily and quickly formed in the same exposure process, thereby reducing the manufacturing cost and manufacturing time of the roll master 100.

[0150] [5. Roll master manufacturing method] Next, a method for manufacturing the roll master 100 according to this embodiment will be described with reference to Fig. 9 and Fig. 10. Fig. 9 and Fig. 10 are process diagrams showing the method for manufacturing the roll master 100 according to this embodiment.

[0151] In this embodiment, lithography using laser light, which can control the irradiation position with high precision, is used to form a concave-convex pattern such as the fine concave-convex structure 120 on the outer peripheral surface of the master substrate 110, thereby manufacturing the roll master 100 according to this embodiment. By using such laser light lithography, it is possible to precisely control the arrangement of the concave-convex pattern such as the fine concave-convex structure 120.

[0152] The method for manufacturing the roll master 100 according to this embodiment includes a film-forming step (S10), an exposure step (S12), a development step (S14), and an etching step (S16). First, in the film-forming step (S10), a resist layer 111 is formed on the outer peripheral surface of the master substrate 110. Next, in the exposure step (S12), a latent image 112 is formed by irradiating the resist layer 111 with laser light. Furthermore, in the development step (S14), the resist layer 111 on which the latent image 112 has been formed is developed to form a pattern in the resist layer 111. Thereafter, in the etching step (S16), etching is performed using the resist layer 111 on which the pattern has been formed as a mask, to form a concavo-convex pattern (such as the fine concavo-convex structure 120 and the spiral groove 131) on the outer peripheral surface of the master substrate 110. Each step in the method for manufacturing the roll master 100 according to this embodiment will be described below.

[0153] (S10) Film formation process In the film formation process, first, as shown in A of FIG. 9, a master substrate 110 of the roll master 100 is prepared. The master substrate 110 is, for example, a cylindrical or columnar glass master. Next, as shown in B of FIG. 9, a resist layer 111 is formed on the outer peripheral surface of the master substrate 110. The resist layer 111 contains an inorganic or organic material capable of forming a latent image 112 by laser light. Examples of inorganic materials that can be used include metal oxides containing one or more transition metals such as tungsten or molybdenum. The resist layer containing an inorganic material can be formed by, for example, sputtering. Examples of organic materials that can be used include novolac resists and chemically amplified resists. The resist layer containing an organic material can be formed by, for example, spin coating.

[0154] (S12) Exposure process Next, in the exposure step, as shown in C of Fig. 9, a laser beam 202 is irradiated onto the resist layer 111 formed on the outer peripheral surface of the master substrate 110. Specifically, the roll master 100 is placed on the turntable 227 of the exposure device 200 shown in Fig. 6, and while the roll master 100 is rotated, a laser beam 202 (exposure beam) is irradiated onto the resist layer 111. At this time, the laser beam 202 is irradiated onto the resist layer 111 while moving in the axial direction (roll width direction) of the roll master 100, thereby exposing the resist layer 111 along a spiral irradiation locus. As a result, latent images 112A and 112B (hereinafter, sometimes collectively referred to as "latent images 112") corresponding to the irradiation locus of the laser beam 202 are formed in the resist layer 111.

[0155] In this embodiment, a laser beam 202 is intermittently irradiated along a spiral irradiation locus onto a concave-convex pattern region 102 in the center in the roll width direction of the outer circumferential surface of the roll master 100. As a result, the resist layer 111 in the concave-convex pattern region 102 is exposed over the entire surface with an exposure pattern corresponding to the fine concave-convex structure 120 (for example, a pattern in which the circular dot pattern shown in FIG. 8 is arranged in a hexagonal lattice shape). As a result, a latent image 112A of the exposure pattern corresponding to the fine concave-convex structure 120 is formed in the resist layer 111 in the concave-convex pattern region 102.

[0156] Meanwhile, laser light 202 is continuously irradiated along a spiral irradiation locus onto line marker regions 103 on both ends in the roll width direction of the outer circumferential surface of roll master 100. As a result, resist layer 111 in line marker region 103 is spirally exposed to an exposure pattern corresponding to spiral groove 131. As a result, latent image 112B of the exposure pattern corresponding to spiral groove 131 is formed in resist layer 111 in line marker region 103. Note that the exposure pattern corresponding to spiral groove 131 does not necessarily have to be a continuous spiral. For example, a discontinuous spiral exposure pattern may be formed by discontinuously irradiating laser light 202 along a spiral irradiation locus.

[0157] (S14) Development process Next, in the development process, as shown in A of FIG. 10, the resist layer 111 on which the latent image 112 is formed is developed using a developer. As a result, a pattern of openings 113A and 113B (hereinafter sometimes collectively referred to as "openings 113") corresponding to the latent images 112A and 112B, respectively, is formed in the resist layer 111. For example, if the resist layer 111 contains the inorganic material described above, an alkaline solution such as an aqueous solution of TMAH (TetraMethylAmmonium Hydroxide) can be used to develop the resist layer 111. If the resist layer 111 contains the organic material described above, various organic solvents such as esters or alcohols can be used to develop the resist layer 111.

[0158] In the developing step, for example, while rotating the roll master 100, a developer is dropped onto the resist layer 111 to develop the resist layer 111. As a result, a plurality of openings 113 are formed in the resist layer 111, as shown in A of Fig. 10. When the resist layer 111 is formed using a positive resist, the exposed portions exposed to the laser light 202 dissolve faster in the developer than the non-exposed portions, and therefore a pattern of openings 113 corresponding to the latent image 112 (exposed portions) is formed in the resist layer 111.

[0159] In this embodiment, openings 113A are formed in the concave-convex pattern region 102 in an opening pattern (for example, a pattern in which the circular dot pattern shown in FIG. 8 is arranged in a hexagonal lattice) corresponding to the fine concave-convex structure 120. On the other hand, spiral openings 113B are formed in the line marker region 103 in an opening pattern corresponding to the spiral groove 131.

[0160] (S16) Etching process Next, in the etching process, the pattern of the resist layer 111 in which the openings 113 are formed is used as a mask to etch the outer peripheral surface of the master substrate 110. As a result, as shown in FIG. 10B, a concavo-convex pattern (fine concavo-convex structure 120, spiral groove 131) corresponding to the exposure pattern and the pattern of the openings 113 is formed on the outer peripheral surface of the master substrate 110. Etching of the master substrate 110 may be performed by either dry etching or wet etching. When the master substrate 110 is made of a glass material mainly containing SiO (for example, quartz glass), etching of the master substrate 110 can be performed by dry etching using a carbon fluoride gas or wet etching using hydrofluoric acid or the like.

[0161] According to the etching process of this embodiment, a fine concave-convex structure 120 corresponding to the opening 113A is formed as a concave-convex pattern in the concave-convex pattern region 102 of the outer peripheral surface of the master substrate 110. The fine concave-convex structure 120 is, for example, a moth-eye structure in which a plurality of recesses 121 and protrusions 122 are arranged in a hexagonal lattice pattern at a pitch P' of nano-order (for example, 350 nm or less) equal to or less than the wavelength of visible light. Meanwhile, a spiral groove 131 corresponding to the opening 113B is formed as a concave-convex pattern in the line marker region 103 of the outer peripheral surface of the master substrate 110. The track pitch P of this spiral groove 131 in the roll width direction is t ' is on the order of microns (e.g., 500 nm or more, 1 mm or less), which is greater than the wavelength of visible light.

[0162] As described above, in the etching process according to this embodiment, the resist layer 111 having the opening pattern (openings 113A, 113B) formed therein is used as a mask to simultaneously etch the entire outer peripheral surface of the master substrate 110. This makes it possible to simultaneously process the fine concave-convex structure 120 (a concave-convex pattern for anti-reflection) of the concave-convex pattern region 102 and the spiral groove 131 (a concave-convex pattern for visual recognition as a marker) of the line marker region 103 on the outer peripheral surface of the master substrate 110 in a single etching process. Moreover, since the fine concave-convex structure 120 and the spiral groove 131 are formed simultaneously under the same etching conditions, the depth h' of the groove 131 is substantially the same as the depth H' of the recess 121 of the fine concave-convex structure 120.

[0163] In contrast to this, in the past, when forming a marker for defect management of the roll master (a mark that indicates the position of the roll master in the roll circumferential direction and is formed with concaves and convexes that can be transferred to a film) on the surface of the roll master in addition to the fine concave-convex structure, an additional process of processing the marker for defect management was required after the etching process of forming the fine concave-convex structure. Therefore, in the past, there was a problem in that when the marker was processed separately after the formation of the fine concave-convex structure, there was a risk of generating another defect on the outer peripheral surface of the roll master.

[0164] Furthermore, conventionally, the unevenness of the marker is formed by cutting or other processes other than etching, making it difficult to control the processing accuracy of the unevenness of the marker on the nanometer order. Therefore, the depth of the recesses of the fine uneven structure on the outer peripheral surface of the roll master differs from the depth of the recesses of the marker. Therefore, even in a film formed by transferring the unevenness pattern of the roll master, the height of the convex portions of the fine uneven structure differs from the height of the convex portions of the marker, resulting in a difference in height on the film surface. As a result, when the film is wound into a film roll, problems such as winding distortion occur.

[0165] In this regard, according to the manufacturing method of the roll master 100 according to the present embodiment, when forming the spiral groove 131 (a concave-convex pattern for visual recognition as a marker) in the line marker region 103 in addition to the fine concave-convex structure 120 (a concave-convex pattern for anti-reflection) in the concave-convex pattern region 102 on the surface of the roll master 100, an additional step for processing the groove 131 as a marker is not required. In other words, the fine concave-convex structure 120 in the concave-convex pattern region 102 and the spiral groove 131 in the line marker region 103 can be processed simultaneously in a single etching step. Therefore, according to the present embodiment, the concave-convex pattern of the fine concave-convex structure 120 and the concave-convex pattern of the groove 131 as a marker are processed simultaneously, so no additional step is required, and there is an advantage in that there is no risk of generating new defects on the outer peripheral surface of the roll master 100 due to the additional step.

[0166] Moreover, according to the method for manufacturing the roll master 100 of this embodiment, the fine concave-convex structure 120 and the spiral groove 131 are simultaneously formed under the same etching conditions in a single etching step. As a result, the depth h' of the groove 131 becomes substantially the same as the depth H' of the recess 121 of the fine concave-convex structure 120. Therefore, even in the optical film 1 formed by transferring the concave-convex pattern of the roll master 100, the height H of the convex portions 21 of the fine concave-convex structure 20 and the height h of the convex streak portion 31 (marker) become substantially the same, and no difference in height occurs between the convex portions on the surface of the optical film 1. This has the advantage that defects such as winding distortion do not occur when the optical film 1 is wound into a film roll.

[0167] [6. Optical film manufacturing method] Next, a method for producing the optical film 1 according to this embodiment will be described with reference to Fig. 11 and Fig. 12. Fig. 11 and Fig. 12 are process diagrams showing the method for producing the optical film 1 according to this embodiment.

[0168] The method for producing the optical film 1 according to this embodiment includes a step (S20) of preparing a roll master 100, a coating step (S22) of coating a resin layer 12A made of a curable resin on the surface of the substrate 11 of the optical film 1, a first transfer step (S24) of transferring a transfer pattern formed on the outer peripheral surface of the roll master 100 to the resin layer 12A of the optical film 1, and a molding step (S28) of molding the optical film 1 into a predetermined shape. Furthermore, when a concave-convex pattern is provided on both sides of the optical film 1, the method for producing the optical film 1 according to this embodiment may include a second coating and transfer step (S26) in addition to the above steps.

[0169] (S20) Roll master preparation process The preparation process for the roll master 100 may be, for example, each of the steps (film formation step (S10), exposure step (S12), development step (S14), and etching step (S16)) in the method for manufacturing the roll master 100 according to this embodiment described above with reference to Figures 9 and 10. By the method for manufacturing the roll master 100, the roll master 100 having the concave-convex pattern region 102 and the line marker region 103 formed on the outer peripheral surface is suitably prepared.

[0170] Coating process (S22) In the coating step, an uncured resin layer 12A made of a curable resin (transfer material) is coated on the surface of the substrate 11 of the optical film 1. The curable resin (transfer material) is a resin material that has fluidity before curing, and is, for example, an energy ray-curable resin such as an ultraviolet-curable resin or a photocurable resin. In this embodiment, the transfer pattern of the roll master 100 is continuously transferred to the resin layer 12A of the optical film 1 using a roll-to-roll system, so the coating step (S22) and the subsequent transfer step (S24) are performed simultaneously in parallel.

[0171] (S24) Transfer process In the transfer step (S24), the transfer pattern on the outer peripheral surface of the roll master 100 is transferred to one surface of the optical film 1. In detail, as shown in A of FIG. 11 , an uncured resin layer 12A (transfer material) applied to the substrate 11 of the optical film 1 is brought into close contact with the outer peripheral surface of the roll master 100. Thereafter, energy rays such as ultraviolet rays are irradiated onto the resin layer 12A from the light source 58 to cure the resin layer 12A. Thereafter, the substrate 11 integrated with the cured resin layer 12A (corresponding to the resin layer 12) is peeled off from the roll master 100.

[0172] This results in the optical film 1 shown in B of Fig. 11. In the optical film 1, a resin layer 12 is laminated on the surface of a substrate 11, and a fine uneven structure 20 and a ridge portion 31 are formed on the surface of the resin layer 12. If necessary, an intermediate layer (not shown), such as an adhesion layer, an adhesive layer, or a base layer, may be further provided between the resin layer 12 and the substrate 11 of the optical film 1.

[0173] According to the transfer process of this embodiment, the transfer pattern (fine uneven structure 120, spiral groove 131) on the outer peripheral surface of the roll master 100 is simultaneously transferred to the resin layer 12 of the optical film 1, and the fine uneven structure 20 and multiple convex streak portions 31 are simultaneously and integrally formed on the surface of the resin layer 12.

[0174] In detail, the fine concave-convex structure 120 of the concave-convex pattern region 102 of the roll master 100 is transferred to the concave-convex pattern region 2 of the resin layer 12 of the optical film 1, thereby forming the fine concave-convex structure 120 having an anti-reflection function in the concave-convex pattern region 2. The fine concave-convex structure 120 and the fine concave-convex structure 20 have mutually inverted shapes. Furthermore, the spiral groove 131 of the line marker region 103 of the roll master 100 is transferred to the line marker region 3 of the resin layer 12 of the optical film 1, thereby forming a plurality of ridge portions 31 that function as a diffraction grating in the line marker region 3. The spiral groove 131 and the stripe-shaped ridge portions 31 have mutually inverted shapes.

[0175] As described above, according to the transfer step of this embodiment, a transfer pattern including the fine concave-convex structure 120 formed in the concave-convex pattern region 102 of the roll master 100 and the spiral groove 131 formed in the line marker region 103 is simultaneously transferred to the resin layer 12 of the optical film 1. That is, in the optical film 1, the fine concave-convex structure 20 in the concave-convex pattern region 2 and the multiple convex streak portions 31 in the line marker region 3 are integrally formed in the same resin layer 12. Therefore, two different concave-convex patterns (the fine concave-convex structure 120 and the spiral groove 131) can be efficiently transferred in a single transfer step, thereby improving the productivity of the optical film 1.

[0176] By the above-described coating step (S22) and transfer step (S24), a concave-convex pattern (fine concave-convex structure 20 and ridge portion 31) is formed in the resin layer 12 on one surface of the optical film 1, as shown in B of FIG. 11. The resin layer 12 having the concave-convex pattern may be provided on only one surface (one side) of the optical film 1, as shown in B of FIG. 11, or may be provided on both surfaces (front and back sides) of the optical film 1, as shown in B of the following FIG. 12. In the latter case, a second coating and transfer step (S26), which will be described next, may be carried out.

[0177] (S26) Second coating and transfer process 12A, after the first transfer step (S24), a resin layer 12A made of a curable resin is also applied to the other surface (rear surface) of the substrate 11 of the optical film 1. Next, the transfer pattern formed on the outer peripheral surface of the roll master 100 is transferred to the resin layer 12A on the other surface (rear surface) of the optical film 1.

[0178] Specifically, as shown in A of Fig. 12, an uncured resin layer 12A coated on the other surface of the film substrate 11 is brought into close contact with the outer peripheral surface of the roll master 100. Next, the resin layer 12A is irradiated with energy rays such as ultraviolet rays from a light source 58 to cure the resin layer 12A. Thereafter, the substrate 11 integrated with the cured resin layer 12A (corresponding to the resin layer 12) is peeled off from the roll master 100. This results in an optical film 1 in which the resin layers 12 are laminated on both the front and back surfaces of the substrate 11 and the microrelief structure 20 and the ridge portions 31 are formed on the surface of the resin layer 12, as shown in B of Fig. 12.

[0179] (S28) Molding process Next, in the molding step, the optical film 1 obtained in the transfer step (S24 or S26) is molded into a predetermined size and shape. For example, the optical film 1 is cut to a predetermined size, cut out into a desired shape, or punched into a desired shape using a mold to form shielding members such as face shields and eye shields, and other optical member products (sheet products). A cutting machine, a laser processing device, a punching press, or the like can be used for such molding. The use of a punching press is preferable because it allows the formation of the score lines required for the shielding member and the cutting process to be performed in a single process.

[0180] Next, a method for continuously transferring a transfer pattern from a roll master 100 to the optical film 1 by a roll-to-roll system in a method for producing the optical film 1 according to this embodiment will be described with reference to Fig. 13. Fig. 13 is a schematic diagram showing the configuration of a transfer device 5 according to this embodiment.

[0181] 13, the transfer device 5 includes a roll master 100, a substrate supply roll 51, a take-up roll 52, guide rolls 53 and 54, a nip roll 55, a peeling roll 56, an application device 57, and a light source 58. In other words, the transfer device 5 shown in FIG. 13 is a roll-to-roll type imprint transfer device.

[0182] The substrate supply roll 51 is, for example, a roll on which the substrate 11 of the optical film 1 is wound into a roll. The take-up roll 52 is a roll for winding up the optical film 1 with the concave-convex pattern 105 transferred to the resin layer 12. The guide rolls 53 and 54 are rolls for transporting the substrate 11 before and after transfer. The nip roll 55 is a roll for pressing the substrate 11 with the uncured resin layer 12A applied thereto against the outer peripheral surface of the roll master 100. The peeling roll 56 is a roll for peeling off the substrate 11 with the resin layer 12 with the concave-convex pattern 105 transferred thereto from the roll master 100.

[0183] The coating device 57 coats the substrate 11 with a transfer material made of, for example, an uncured curable resin composition, to form an uncured resin layer 12A on the substrate 11. The coating device 57 may be, for example, a gravure coater, a wire bar coater, or a die coater. The light source 58 is a light source that emits light of a wavelength capable of curing the photocurable resin composition, and is, for example, an ultraviolet lamp.

[0184] The curable resin composition may be, for example, a photocurable resin that is cured by irradiation with light of a predetermined wavelength. Specifically, the photocurable resin composition may be an ultraviolet-curable resin such as an acrylic resin acrylate or an epoxy acrylate. The photocurable resin composition may also contain an initiator, a filler, a functional additive, a solvent, an inorganic material, a pigment, a charge inhibitor, or a sensitizing dye, as necessary.

[0185] The uncured resin layer 12A may be formed of a thermosetting resin composition. In this case, the transfer device 5 may be provided with a heat source (e.g., a heater) instead of the light source 58, and the resin layer 12A may be cured by heating it with the heat source. The thermosetting resin composition may be, for example, a phenol resin, an epoxy resin, a melamine resin, or a urea resin.

[0186] Next, a roll-to-roll transfer method using the transfer device 5 having the above configuration will be described.

[0187] First, the strip-shaped substrate 11 wound around the substrate supply roll 51 is unwound from the substrate supply roll 51 and continuously fed out via the guide roll 53. Next, a photocurable resin composition (transfer material) is continuously applied onto the surface of the substrate 11 by the application device 57, and an uncured resin layer 12A is laminated on the substrate 11. Furthermore, the resin layer 12A laminated on the substrate 11 is pressed against the outer peripheral surface of the roll master 100 by the nip roll 55. As a result, the concavo-convex pattern 105 (for example, the above-mentioned fine concavo-convex structure 120 and grooves 131) formed on the outer peripheral surface of the roll master 100 is continuously transferred to the resin layer 12A.

[0188] Next, the resin layer 12A onto which the concave-convex pattern 105 has been transferred is cured by irradiation with light from the light source 58. As a result, an inverted structure of the concave-convex pattern 105 (for example, the above-described fine concave-convex structure 20 and the convex streak portion 31) is formed in the resin layer 12. Thereafter, the optical film 1 composed of the resin layer 12 onto which the concave-convex pattern 105 has been transferred and the substrate 11 is peeled off from the roll master 100 by a peeling roll 56. Thereafter, the optical film 1 is sent out to a winding roll 52 via a guide roll 54, and is wound up into a roll by the winding roll 52.

[0189] As described above, the transfer device 5 according to this embodiment can continuously transfer the concave-convex pattern 105 formed on the outer peripheral surface of the roll master 100 by a roll-to-roll method to manufacture the optical film 1. Therefore, the optical film 1 can be mass-produced efficiently.

[0190] Furthermore, when a transparent microrelief structure 20 such as a moth-eye structure is transferred using a roll-to-roll process, a curable resin (uncured resin layer 12A) such as a transparent UV-curable resin is applied to the surface of the transparent substrate 11, and then the substrate 11 is pressed against the outer circumferential surface of the rotating roll master 100. As a result, the curable resin spreads between the outer circumferential surface of the roll master 100 and the substrate 11, thereby increasing the application area of ​​the curable resin. In this case, it is difficult for an operator to visually confirm the area where the transparent curable resin is applied to the transparent substrate 11 (particularly, the application area in the roll width direction). Therefore, the application area of ​​the curable resin in the roll width direction cannot be properly controlled, which can easily cause problems such as the curable resin spilling out from between the roll master 100 and the substrate 11 or the curable resin being missing from a portion of the surface of the substrate 11. Therefore, it is desirable to provide easily visible line markers at the ends of the roll master 100 in the roll width direction, all around the circumference of the roll master 100.

[0191] In this regard, according to the present embodiment, as shown in FIG. 5 , strip-shaped line marker regions 103 are provided around the entire circumference of the roll master 100 near both ends in the roll width direction. Spiral grooves 131 functioning as a diffraction grating are formed in the line marker regions 103, causing rainbow-colored diffused light to be emitted from the line marker regions 103 due to light diffraction and interference. Therefore, workers can easily see the line marker regions 103 provided at both ends in the roll width direction of the roll master 100. Therefore, using the position of the visible line marker regions 103 as a guide, the area coated with the transparent curable resin can be visually confirmed and controlled. This allows the supply rate of the applied curable resin to be controlled, thereby appropriately controlling the area coated with the curable resin. As a result, defects such as overflowing of the curable resin and missing areas can be suppressed, improving the productivity and quality of the optical film 1.

[0192] [7. Application Examples] Next, various application examples of the optical film 1 according to this embodiment will be described.

[0193] [7.1. Improving visibility of film products] First, an example of forming an antireflection film product (for example, a shielding member such as an eye shield or face shield, or other optical member product) by punching the optical film 1 according to this embodiment will be described with reference to Fig. 14. Fig. 14 is a plan view showing an example of punching a plurality of eye shields 4 from the optical film 1 according to this embodiment.

[0194] The optical film 1 according to this embodiment may be stored, for example, as a film roll (see FIG. 1) in which a strip-shaped film is wound into a roll. When shielding members or other optical member products (sheet products) are manufactured from such a film roll, the strip-shaped optical film 1 unwound from the film roll is punched to form a film product of a predetermined shape. Note that the strip-shaped optical film 1 unwound from the film roll may be cut to a predetermined length before punching.

[0195] As shown in Fig. 14, when a plurality of eye shields 4 are punched out from the optical film 1, it is preferable to punch out the eye shields 4 so that at least a portion of each eye shield 4 includes the line marker regions 3 at both widthwise ends of the optical film 1. In the example of Fig. 14, the eye shields 4 are punched out in two rows in the widthwise direction (Y direction) of the strip-shaped optical film 1 so that the line marker region 3 is included at one end of each eye shield 4.

[0196] As described above, the line marker area 3 includes a periodic structure of multiple ridges 31 that function as a diffraction grating. Because the line marker area 3 shines in rainbow colors, the user can easily see the line marker area 3. Therefore, even if the majority of the area of ​​the punched sheet of eye shield 4 is a transparent area (concave-convex pattern area 2) that has an anti-reflection function, if the line marker area 3 is included in a portion of the eye shield 4, the presence of the line marker area 3 can significantly improve the visibility of the sheet of eye shield 4.

[0197] This allows the user to easily visually identify the mostly transparent sheet of eye shields 4 using the line marker area 3 as a clue, improving the ease of handling the sheet of eye shields 4. For example, when the user carries or puts on or takes off the sheet of eye shields 4, the user can easily visually identify and handle the eye shields 4. Furthermore, even if the sheet of eye shields 4 is dropped on the floor, it can be easily found.

[0198] Thus, according to this embodiment, even if the majority of a sheet product such as an eye shield 4 obtained by molding the optical film 1 is transparent, a visible line marker area 3 is formed in a portion of it, thereby significantly improving the ease of handling of products such as the eye shield 4 by users.

[0199] 14 illustrates an example in which the line marker area 3 is included on one side edge of the eye shield 4, but the present invention is not limited to this example. As long as the line marker area 3 is present in a part of a film product such as the eye shield 4, the position, orientation, range, number, etc. of the line marker area 3 in the film product are not particularly limited.

[0200] [7.2. Defect management of roll master] Next, a method for managing defects 107 in the roll master 100 using markers 106 that indicate the circumferential position of the roll master 100 will be described with reference to Fig. 15. Fig. 15 is an explanatory diagram showing a defect 7 in the optical film 1 according to this embodiment, a defect 107 in the roll master 100, and markers 6 and 106.

[0201] As described above, in the method for producing the optical film 1 according to this embodiment, the concave-convex pattern (the fine concave-convex structure 120 of the concave-convex pattern region 2) formed on the outer peripheral surface of the roll master 100 is continuously transferred to the resin layer 12 of the optical film 1 by a roll-to-roll process. During this transfer process, as shown in FIG. 15 , defects 107 may occur in the concave-convex pattern on the outer peripheral surface of the roll master 100 for some reason. When the defects 107 are transferred from the roll master 100 to the optical film 1, defects 7 corresponding to the defects 107 also periodically occur on the surface of the optical film 1. This leads to deterioration in the performance and quality of the optical film 1 and a decrease in yield.

[0202] Therefore, in the roll-to-roll transfer method, defect management of the roll master 100 is important to improve the productivity and quality of the optical film 1. Here, in order to manage defects 107 in the concave-convex pattern (the fine concave-convex structure 120 in the concave-convex pattern region 2) of the roll master 100, it is desirable to provide markers 106 in an area of ​​the outer circumferential surface of the roll master 100 other than the concave-convex pattern region 2. Furthermore, in order to identify the positions of the defects 107 in the roll master 100 from the positions of defects 7 that occur periodically in the optical film 1 (hereinafter referred to as "periodic defects 7"), it is preferable that markers 106 are engraved on the outer circumferential surface of the roll master 100 and that these markers 106 are transferred to the optical film 1.

[0203] Therefore, in this embodiment, as shown in Fig. 15, a marker 106 is provided in the line marker region 103 of the roll master 100. The marker 106 is identification information (a mark) that indicates a reference position in the roll circumferential direction of the roll master 100. The marker 106 in the example of Fig. 15 is configured as a circular mark engraved in the line marker region 103, but the shape of the marker 106 is not important as long as it serves as a mark that indicates a reference position in the roll circumferential direction.

[0204] By providing markers 106 in the line marker region 103 of the roll master 100, markers 6 having an inverted shape of the markers 106 are periodically transferred to the line marker region 3 of the optical film 1. The period (pitch) of the markers 6 in the longitudinal direction of the optical film 1 is the circumferential length of the roll master 100.

[0205] In this way, if the markers 6 are present in the line marker region 3 of the optical film 1, the positions of the defects 107 on the outer peripheral surface of the roll master 100 (positions in the roll circumferential direction) can be easily identified based on the coordinate positions of the periodic defects 7 on the concave-convex pattern region 2 of the optical film 1 (the distance from the markers 6 to the defects 7). In this case, even if the defects 107 on the outer peripheral surface of the roll master 100 are minute and difficult to find with the naked eye, the information on the coordinate positions of the periodic defects 7 on the optical film 1 makes it possible to identify the positions of the minute defects 107 on the outer peripheral surface of the roll master 100. If the positions of the defects 107 on the roll master 100 can be identified, the defects 107 can be repaired to restore the quality of the optical film 1, thereby reducing the occurrence of defective products and improving productivity.

[0206] As described above, according to this embodiment, when periodic defects 7 occur in the optical film 1, the position of the defect 107 in the roll master 100 itself can be identified from the coordinate position of the defect 7 relative to the marker 6, and measures to address the defect can be implemented quickly. Therefore, defect management and measures to address the defect can be implemented effectively.

[0207] Conversely, the position of the periodic defect 7 on the optical film 1 (the distance from the marker 6 to the defect 7) can also be identified from the coordinate position (position in the roll circumferential direction) of the defect 107 on the outer peripheral surface of the roll master 100. If the position of the periodic defect 7 on the optical film 1 is known, a punching position for the optical film 1 can be specified so as to avoid the position of the periodic defect 7, thereby making it possible to form a high-quality film product that does not contain periodic defects 7.

[0208] [7.3. Traceability management using cut-out characters] Next, with reference to Fig. 16, an application example will be described in which identification information such as markers, letters, symbols, etc. is displayed in the line marker region 3 as cut-out characters and used for traceability management of the optical film 1. Fig. 16 is a plan view showing markers 8 and cut-out characters 9 formed in the line marker region 3 of the optical film 1 according to this embodiment.

[0209] 16, for example, circular markers 8 and cut-out letters 9 consisting of alphabetical characters are formed in the line marker region 3 of the optical film 1. These markers 8 and cut-out letters 9 are visibly displayed by the portions (white portions) in the line marker region 3 where the convex stripes 31 are not formed.

[0210] In the line marker region 3 of the example in FIG. 16, multiple ridges 31 are formed intermittently along the longitudinal direction of the line marker region 3. The portions where ridges 31 are formed function as the diffraction grating described above, becoming visible regions that glow in rainbow colors. On the other hand, the portions where ridges 31 are not formed do not function as diffraction gratings and do not glow in rainbow colors, but are displayed as hollow characters in contrast to the surrounding rainbow-colored regions (portions where ridges 31 are formed). In this way, depending on whether or not ridges 31 are formed within the line marker region 3, it is possible to visibly display identification information such as markers 8, hollow characters 9, and other arbitrary symbols.

[0211] In this way, in order to display the markers 8, cut-out characters 9, etc. in the line marker region 3 of the optical film 1 depending on the pattern of whether or not the convex streak portions 31 are formed, it is necessary to form a transfer pattern corresponding to the pattern in the line marker region 103 of the roll master 100. For this reason, by forming the spiral grooves 131 intermittently in the line marker region 103 of the roll master 100 as well, the identification information such as the markers 8, cut-out characters 9, etc. is displayed in the parts (white parts) where the grooves 131 are not formed.

[0212] Therefore, in the exposure step (S12) of the above-described method for manufacturing the roll master 100, the on / off of laser light irradiation is controlled in accordance with the pattern of identification information such as markers 8 and cut-out characters 9, to form an exposure pattern corresponding to the identification information in the resist layer 111 of the master substrate 110. As a result, a transfer pattern representing the identification information such as markers 8 and cut-out characters 9 can be formed in the line marker region 103 of the roll master 100 depending on whether or not grooves 131 are formed. Then, the transfer pattern representing the identification information is transferred from the line marker region 103 of the roll master 100 to the line marker region 3 of the optical film 1. As a result, the identification information such as the markers 8 and cut-out characters 9 shown in FIG. 16 can be displayed in the line marker region 3 of the optical film 1.

[0213] As described above, according to this embodiment, identification information including the markers 8, the cut-out characters 9, and other symbols is displayed in the line marker area 3 of the optical film 1. This makes it possible to provide various pieces of identification information related to the optical film 1, the roll master 100, etc.

[0214] 16 can be used as a mark indicating the reference position in the circumferential direction of the roll master 100 used in manufacturing the optical film 1. By displaying the marker 8 indicating the reference position in the circumferential direction of the roll master 100, it is possible to appropriately manage and take measures against defects in the roll master 100 and the optical film 1, as described above with reference to FIG.

[0215] 16 may be, for example, letters or symbols that represent the lot number used in the production of the optical film 1. By displaying the lot number using the letter 9, it is possible to provide a worker with identification information for specifying the production lot of the optical film 1 and the roll master 100 used in the production of the optical film 1.

[0216] Therefore, if a defect 7 occurs in the optical film 1, it is possible to identify the production lot of the optical film 1 and the roll master 100. Therefore, this identification information makes it possible to easily and suitably realize highly reliable traceability management and defect management.

[0217] Furthermore, because the line marker area 103 of the roll master 100 and the line marker area 3 of the optical film 1 are long and strip-like, it is possible to imprint and display long identification information, such as a lot number, in cut-out characters in the line marker areas 103, 3. This makes it possible to display detailed identification information, thereby achieving more detailed traceability management.

[0218] [8. Summary] The optical film 1 according to this embodiment, the method for producing the same, and the roll master 100 used in the production method have been described in detail above.

[0219] In the optical film 1 according to this embodiment, strip-shaped line marker regions 3 extending in the longitudinal direction of the film are provided at both ends in the film width direction. A plurality of ridges 31 are formed in the line marker regions 3. The plurality of ridges 31 are arranged at a track pitch P of micrometers, which is equal to or greater than the wavelength of visible light. t are arranged at intervals from each other. As a result, the multiple ridges 31 in the line marker area 3 function as a diffraction grating, and light incident on the line marker area 3 is diffracted and interfered by the ridges 31, resulting in light being separated into individual wavelengths. As a result, rainbow-colored diffused light is emitted from the line marker area 3, making the line marker area 3 a visible area. The rainbow-colored line marker area 3 has higher visibility to the naked eye than the transparent uneven pattern area 2.

[0220] Therefore, a user of an optical film product (e.g., an eye shield, a face shield, etc.) using the optical film 1 can easily see the line marker region 3 that shines in rainbow colors even if the user has difficulty seeing the transparent concave-convex pattern region 2 of the optical film 1. This improves visibility when the user handles the transparent optical film product.

[0221] Furthermore, workability is improved when handling the optical film 1, which is a transferred product, in the production process, because the worker can see the line marker area 3 that shines in rainbow colors in the transparent optical film 1. Furthermore, because the line marker area 103 is also formed on the transparent roll master 100, by the same principle, the visibility of the transparent roll master 100 is also improved, and workability in handling the roll master 100 can also be improved.

[0222] Furthermore, according to the method for producing the optical film 1 of this embodiment, in the transfer step (S24) shown in FIG. 11 , the transfer patterns of the concave-convex pattern region 102 and the line marker region 103 formed on the outer peripheral surface of the roll master 100 are simultaneously transferred to the surface of the resin layer 12A on the film substrate 11, thereby producing the optical film 1. This makes it possible to easily form the concave-convex pattern region 2 (anti-reflection region) and the line marker region 3 (visible region) on the surface of the optical film 1 in the same processing step. Furthermore, both the fine concave-convex structure 20 of the concave-convex pattern region 2 and the convex streak portion 31 of the line marker region 3 can be integrally formed on the same resin layer 12 laminated on the surface of the substrate 11 of the optical film 1. This allows for efficient mass production of the optical film 1.

[0223] Furthermore, when the line marker region 3 of the optical film 1 is manufactured in an additional process (for example, a separate printing process) separate from the transfer process for forming the concave-convex pattern region 2, the additional process may cause new defects in the concave-convex pattern region 2. However, according to the manufacturing method for the optical film 1 according to this embodiment, the concave-convex pattern region 2 and the line marker region 3 are integrally formed simultaneously in the same process, so no additional process is required and no new defects are caused to occur.

[0224] Furthermore, according to this embodiment, highly visible line marker areas 103, 103 are present at both ends of the roll width direction of the roll master 100 over the entire circumference of the roll master 100. Therefore, when a transfer material such as a transparent curable resin is applied to the transparent substrate 11 pressed against the outer peripheral surface of the roll master 100 in the transfer step (S24) of the roll-to-roll method, the application width can be suitably controlled using the line marker areas 103, 103 at both ends in the roll width direction as references.

[0225] Furthermore, according to this embodiment, a strip-shaped optical film 1 is manufactured using a roll master 100 having a line marker region 103 present around its entire periphery. As a result, a highly visible line marker region 3 is formed in a strip shape over the entire longitudinal direction of the strip-shaped optical film 1. Therefore, as shown in FIG. 14 , when an optical film product such as an eye shield 4 is punched out from the strip-shaped optical film 1, the optical film product can include the highly visible line marker region 3 in addition to the transparent concave-convex pattern region 2. This can improve the visibility of optical film products such as the eye shield 4, and therefore the handleability of the optical film product can also be improved.

[0226] 15 , when periodic defects 7 occur in the optical film 1, the coordinate positions of the defects 7 can be identified using the markers 6 transferred to the line marker areas 3 as a reference. This makes it possible to identify the positions of the defects 107 in the roll master 100 itself that produced the optical film 1, and therefore to promptly take measures to address the defects 107. This makes it possible to perform highly accurate defect management of the roll master 100, and also improve the productivity and quality of the optical film 1 produced using the roll master 100.

[0227] 16 , identification information relating to the manufacture of the optical film 1 or the roll master 100 (for example, a character string such as a lot number) can be displayed in the line marker area 3 of the optical film 1 using markers 8 or cut-out characters 9. This allows traceability management and defect management of the optical film 1 to be performed easily and with high precision.

[0228] Furthermore, according to the method for manufacturing the roll master 100 according to this embodiment, the concave-convex pattern region 102 and the line marker region 103 are etched simultaneously. As a result, on the outer peripheral surface of the roll master 100, the depth H' of the recesses 121 in the concave-convex pattern region 102 and the depth h' of the spiral grooves 131 in the line marker region 103 become substantially the same. As a result, even on the surface of the optical film 1 to which the concave-convex pattern of the roll master 100 has been transferred, the height H of the convex portions 21 in the concave-convex pattern region 2 and the height h of the convex streak portions 31 in the line marker region 3 become substantially the same. Therefore, when the optical film 1 is wound into a film roll, defects such as winding distortion are unlikely to occur.

[0229] While the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0230] 1 Optical film 2. Concave and convex pattern area 3 Line marker area 4 Eyeshield 5. Transfer device 6 Markers 7. Defects 8 Markers 9. Cutout characters 11 Base material 12 Resin layer 12A Uncured resin layer 20 Fine uneven structure 21 Convex part 22 recess 31 Convex portion 32 Flat area 100 rolls of master 102 Concave and convex pattern area 103 Line Marker Area 110 Master substrate 111 Resist layer 112 Latent image 113A, 113B opening 120 Fine uneven structure 121 recess 122 convex part 131 Spiral groove 200 Exposure equipment 201 Laser light source 202 Laser light

Claims

1. A roll master used in the production of an optical film, a concave-convex pattern region having a fine concave-convex structure consisting of a plurality of convex or concave portions arranged at a pitch equal to or less than the wavelength of visible light; a strip-shaped line marker area having a plurality of grooves arranged at intervals at a track pitch equal to or greater than the wavelength of visible light; The roll master comprises:

2. The roll master according to claim 1 , wherein the plurality of grooves are formed as spiral grooves formed on the outer peripheral surface of the roll master.

3. The roll master according to claim 2 , wherein the spiral groove has an inverted shape of a plurality of ridges formed in the line marker region of the optical film.

4. The roll master according to any one of claims 1 to 3, wherein the line marker regions are arranged at both ends of the roll master in the width direction.

5. 5. The roll master according to claim 1, wherein a width of the concave-convex pattern region is larger than a width of the line marker region.

6. 6. The roll master according to claim 1, wherein the track pitch of the grooves is 500 nm or more and 1 mm or less.

7. The roll master according to any one of claims 1 to 6, wherein the track pitch of the grooves is 1 µm or more and 10 µm or less.

8. The roll master according to any one of claims 1 to 7, wherein the depth of the grooves is substantially the same as the depth of the recesses of the fine uneven structure.

9. The roll master according to any one of claims 1 to 8, wherein the recessed streak portions are formed intermittently in the line marker region, and identification information including at least one of letters, symbols, and markers is formed in a portion where the recessed streak portions are not formed.

10. The roll master according to claim 9 , wherein the identification information includes a marker that indicates a reference position in a circumferential direction of the roll master.

11. The roll master according to claim 9 , wherein the identification information includes a character or a symbol representing a lot number at the time of manufacturing the optical film.

12. An optical film manufacturing method for manufacturing an optical film using the roll master according to any one of claims 1 to 11, preparing a roll master including the concave-convex pattern region and the line marker region on an outer peripheral surface of the roll master; a step of applying a resin layer made of a curable resin to a surface of a substrate of the optical film; a step of transferring a transfer pattern including the fine concave-convex structure formed in the concave-convex pattern region of the roll master and the plurality of concave streak portions formed in the line marker region onto the resin layer of the optical film, thereby integrally forming the fine concave-convex structure in the concave-convex pattern region of the optical film and the plurality of convex streak portions in the line marker region of the optical film with the resin layer; A method for producing an optical film, comprising:

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