TW201318805A - Manufacturing method of optical sheet, manufacturing method of mold for manufacturing optical sheet, electronic display device and method of mirror finishing - Google Patents

Abstract

A roll mold for producing an optical sheet is provided. The optical sheet may inhibit moire pattern even after transferring uneven streaks caused by cutting to anti-reflection film. According to the present invention, a roll mold for producing an optical sheet, is provided. The roll mold with fine irregularities being formed on its outer circumferential surface produces elongated optical sheet material by making an elongated sheet abut on the outer circumferential surface and transferring the fine irregularities to the elongated sheet. Moreover, in addition to the fine irregularities, a plurality of stripe-like irregular shapes, which extend in parallel with a period P of 5 μ m to 50 μ m, are formed on the outer circumferential surface, of the roll mold for producing an optical sheet.

Description

Method for producing roller-shaped mold for optical plate production, method for producing optical plate, electronic display device, and mirror surface processing method for aluminum base material

The present invention relates to a method for producing a roller-shaped mold for producing an optical sheet, a method for producing an optical sheet, an electronic display device, and a mirror-finishing method for an aluminum base material. More specifically, the present invention relates to a method for producing a roll-shaped mold for producing an optical sheet in which a fine uneven structure formed on an outer peripheral surface is transferred onto an elongated sheet, and a method of manufacturing the same by using the method An optical sheet manufacturing method for a roll-shaped mold for producing an optical sheet, an electronic display device having an optical sheet produced by the production method, and a mirror surface processing method for an aluminum base material.

In recent years, articles having a periodic fine uneven structure having a wavelength of visible light or less on the surface have been known to exhibit an antireflection effect, a lotus effect, and the like. In particular, it is known that an article having a fine uneven structure called moth-eye structure in which fine convex portions having a substantially conical shape are arranged on the surface continuously increases in refractive index from the refractive index of air. The refractive index of the article is an effective anti-reflection method.

As a method of forming such a fine uneven structure on the surface of an article, a method is known in which a liquid mold is sandwiched between a roller-shaped mold having a fine uneven structure on the surface and a long substrate (sheet). In the active energy ray-curable resin composition, the active energy ray-curable resin composition is cured by irradiation with an active energy ray, whereby a cured resin layer is formed on the surface of the substrate to form an optical sheet, and the cured resin layer is formed. A fine uneven structure having a shape complementary to the fine uneven structure of the mold.

In this method, the use of a roll-shaped mold for producing an optical sheet having anodized alumina having a plurality of pores is provided on the surface of a cylindrical aluminum base material due to the simplification of the processing (Patent Document 1) ).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-156695

When a roll-shaped mold for producing an optical sheet is produced by using an aluminum base material as described above, first, the surface of the roll-shaped aluminum base material is mirror-finished to a predetermined smoothness by cutting, and the surface of the mirror-finished base material is anodized. A fine uneven shape is imparted.

This mirror surface processing is performed by rotating the roller-shaped aluminum base material around the longitudinal axis while the tool (turning tool) is along the outer peripheral surface of the base material and along the axis of the roller-shaped aluminum base material. mobile. Therefore, on the surface of the roller-shaped base material, a periodic strip-shaped uneven shape (rabbit) remains as a cutting mark by a tool (turning tool).

When a roller-shaped base material having a strip-shaped uneven shape (raise) remaining in the strip shape is anodized, a fine uneven shape is imparted, and a fine-shaped uneven shape is transferred onto a substrate by a roll-shaped mold manufactured thereby. In addition to the transfer of the fine uneven structure, the optical sheet also transfers a periodic strip-shaped uneven shape (rabbit).

In the optical sheet having the moth-eye structure, since the antireflection property is excellent and the transparency is high, such a strip-shaped uneven shape may be seen.

That is, when such an optical sheet is used in a general anti-reflection application, a strip-like uneven shape is rarely seen, but the inventors of the present invention and the like When the optical sheet to which the strip-shaped uneven shape is transferred is used as an anti-reflection film of an electronic display device such as a liquid crystal display device, it is found that periodic strip-shaped periodic unevenness and drawing of the electronic display device The interference of the elements, while observing the interference figure (interference figure).

Further, it has been found that an antireflection film having a fine uneven structure having a moth-eye structure on the surface is excellent in anti-reflection characteristics, so that if interference fringes are generated, an interference image is more clearly visible than in the case of other optical films. tendency.

In order to prevent the occurrence of such an interference image, the roller-shaped aluminum base material may be processed so as not to form strip-shaped irregularities as the cutting marks, but it is substantially difficult to implement the roller-shaped aluminum without causing the cutting marks at all. Cutting of the surface of the base metal.

The present invention has been made in view of the above problems, and an object of the invention is to provide a method and a method for producing a roller-shaped mold for producing an optical sheet which can suppress an interference image even when a strip-shaped unevenness due to a cutting mark is transferred to an anti-reflection film. A method of producing an optical sheet of such a mold for producing an optical sheet.

According to the present invention, there is provided a method for producing an optical sheet manufacturing mold which is an optical sheet manufacturing mold which has a fine uneven structure on the surface and which transfers the fine uneven structure on the surface onto a sheet to produce an optical sheet. The manufacturing method is characterized in that it comprises the steps of: cutting the surface of the aluminum base material at a predetermined feed length, mirror-finishing the surface of the aluminum base material; and performing anodizing on the surface of the aluminum base material In the step of performing the mirror surface processing, when the feed pitch of the cutting tool is set to F and the radius of curvature of the tip of the cutting tool is set to R, the expression is expressed by the following formula (1). When the value of Ry is 1.5 nm or more and 100 nm or less, the aluminum base material is cut, and Ry=F ² /8R (1).

According to such a configuration, the surface of the aluminum base material can be mirror-finished to have an excellent appearance such as interference fringes or whitening, and the optical sheet can be produced by using a mold made of such an aluminum base material. The interference image is transferred on the optical sheet.

According to another preferred aspect of the present invention, there is provided a method of producing a mold for manufacturing an optical sheet, which is a method for manufacturing a mold for manufacturing the optical sheet, and a feed pitch of the cutting tool is 5 μm or more and 50 μm. the following.

According to another aspect of the present invention, there is provided an optical sheet manufacturing method using a mold manufactured by the above-described manufacturing method, and the optical sheet manufacturing method characterized by comprising the following transfer step of abutting the sheet against the surface of the mold The shape of the surface is transferred onto the sheet to form an optical sheet.

According to another aspect of the present invention, an electronic display device including the optical sheet manufactured by the above manufacturing method is provided.

According to another aspect of the present invention, there is provided a mirror surface processing method which is a mirror surface processing method of an aluminum base material, wherein the aluminum base material is used to form a fine uneven structure on a surface, and to transfer the fine uneven structure a base material for manufacturing an optical sheet manufacturing mold of an optical sheet to a sheet, and the mirror surface processing method is characterized by including a step of cutting a surface of the aluminum base material at a predetermined feed pitch; and in the above step When the feed pitch of the cutting tool is set to F and the radius of curvature of the tip of the cutting tool is set to R, the value of Ry expressed by the following formula (1) is 1.5 nm or more and 100 nm or less. In the manner, the aluminum base material was cut, and Ry=F ² /8R (1).

According to the present invention having such a configuration, it is possible to provide a roller-shaped mold for producing an optical sheet which can suppress an interference image even when a strip-shaped unevenness due to a cutting mark is transferred onto the anti-reflection film, and a roller shape for manufacturing the optical sheet. A method of producing a mold, and a method of producing an optical sheet using the roller-shaped mold for producing the optical sheet.

Hereinafter, a method for producing a roll-shaped mold for producing an optical sheet according to a preferred embodiment of the present invention and a method for producing an optical sheet using the roll-shaped mold for producing the optical sheet will be described with reference to the drawings.

Furthermore, in the present specification, the term "fine concavo-convex structure" or "micro The fine uneven shape refers to a structure or shape in which the average interval (period) of the convex portion or the concave portion is equal to or less than the visible light wavelength, that is, 400 nm or less.

In addition, the "active energy ray" means visible light, ultraviolet light, electron beam, plasma, hot wire (infrared rays, etc.). Further, the (poly)oxyalkylalkylphosphonic acid compound means an oxygen alkylalkylphosphoric acid compound having one oxygen alkyl group or a polyoxyalkylene alkyl phosphate having two or more oxygen alkyl groups. Compound.

Further, the term "(meth)acrylate" means acrylate or methacrylate.

The "rectangular shape" also includes a substantially rectangular shape. For example, even if a portion of the four sides is provided with a cutout portion or a chamfering, the entire shape is substantially rectangular, and these are also included in the "rectangular shape".

First, a roller-shaped mold for manufacturing an optical sheet (hereinafter referred to as a "roller-shaped mold") of the present embodiment will be described.

The roll-shaped mold of this embodiment is produced by the method of the following steps (a) to (g).

(a) A step of performing a cutting process in order to smooth the surface state of the aluminum base material (mirror surface).

(b) A step of anodizing an aluminum base material in an electrolytic solution at a constant voltage to form an oxide film on the surface of the aluminum base material.

(c) a step of removing a part or all of the oxide film to form an anodized pore generating point on the surface of the aluminum base material.

(d) a step of anodizing the aluminum base material again in the electrolytic solution to form an oxide film having pores at the pore generating point.

(e) a step of expanding the pore diameter of the pores.

(f) a step of re-anodizing in the electrolyte after the step (e).

(g) Step (e) and step (f) are repeated to obtain a step of forming a mold having anodized alumina having a plurality of pores on the surface of aluminum.

Step (a)

First, in order to adjust the surface of the aluminum base material which is a material of a roll-shaped mold to the required smoothness, the cutting process using a tool is performed. From the viewpoint of continuously producing an optical sheet, the aluminum base material is preferably a roller-shaped one.

In the molding, the temperature adjustment function is often required. In order to allow the cold and heat medium to pass through the inside of the roller, a sleeve-like structure or the like is used, and a through-hole processor that is divided into a plurality of parts is mainly used. The purity of aluminum is preferably 99% or more, more preferably 99.5% or more, and particularly preferably 99.8% or more. When the purity of aluminum is low, a concavo-convex structure having a size that scatters visible light due to segregation of impurities during anodic oxidation or a regularity of pores obtained by anodization may be lowered.

In turn, most of the tools used use a tool called a turning tool. It is preferable to use a single crystal diamond excellent in shape stability for the tip of a turning tool for cutting aluminum material.

The shape of the turning tool has an R turning tool with an R shape at the top and a flat flat turning tool.

The R turning tool has no restrictions on the change in the diameter of the roller or the machining direction, so it can be easily used. On the other hand, in the case where a large R shape is to be used in order to further increase the surface roughness, the processing machine or the system is manufactured when the turning tool is produced. The manufacturing technology requires high precision, and sometimes the turning body becomes expensive.

Further, since the flat turning tool having a flat top end shape is simple in shape, it is easy to manufacture itself. However, when the diameter of the aluminum base material of the roll shape is changed, it is necessary to perform mounting adjustment, and high mounting precision is required.

Taking these aspects into consideration, the R turning tool is used in the present embodiment, but a flat turning tool can also be used.

The shape of the tip end of the R turning tool used in the present embodiment is preferably an R shape having a radius of 1 mm to 1000 mm, and is preferably an R shape having a radius of 2 mm to 200 mm.

The cutting process of the aluminum base material will be described in detail based on Fig. 1 . In the processing of the roller-shaped workpiece, a lathe is usually used, and the turning tool is rotated in a state where the turning tool of the tool is cut and cut.

When the cylindrical aluminum base material 1 is rotated at a predetermined number of revolutions around the longitudinal axis by the rotation mechanism 2, the stage 6 to which the turning tool 4 is fixed is moved on the X-axis (diameter of the aluminum base material). The turning tool 4 is cut at a predetermined depth on the outer peripheral surface of the aluminum base material 1, and the table 6 and the turning tool 4 are moved at a predetermined speed in the direction of the Z axis (the axis of the aluminum base material 1) to make the cylindrical shape. The outer peripheral surface 1a of the aluminum base material 1 is mirror-finished (Fig. 2).

In the present embodiment, the cutting tool 4 moves 5 μm to 50 μm along the axial direction (Z-axis direction in FIG. 1) while the aluminum base material 1 is rotated about the central axis in the axial direction. At the speed, the cutting tool 4 and the table 6 are moved in the axial direction of the cylindrical aluminum base material 1, and the mirror surface of the cutting is performed.

In the case where the aluminum base material is in the form of a roller, the distance in which the cutting tool 4 that moves during the rotation of the aluminum base material 1 in the axial direction of the aluminum base material 1 is set to Cutting pitch (feed spacing).

Further, when the aluminum base material is in the form of a flat plate, cutting is performed in a predetermined direction (X direction), and the cutting tool 4 is moved by a predetermined distance in a direction (Y direction) orthogonal to a predetermined direction, and further along Cutting in a given direction. By repeating this operation, the surface of the aluminum base material is processed, and the moving distance of the cutting tool 4 in the Y direction at this time is set as the cutting pitch (feed pitch).

By setting the cutting pitch to 5 μm to 50 μm, the interval (pitch) of strip-like irregularities (ridges) remaining on the aluminum base material 1 is 5 μm to 50 μm, and as a result, the method described later is used. In the case where the optical sheet is manufactured by a roll-shaped mold made of an aluminum base material, the arrangement period (pitch) of the strip-shaped uneven structure transferred onto the optical sheet can be set to 5 μm to 50 μm.

The cutting pitch is preferably set to 5 μm to 50 μm.

When the cutting pitch is 5 μm or less, there is a problem that the cutting of the aluminum base material 1 takes a long time; and the turning tool is worn in the middle of the cutting step of the aluminum base material 1, and the turning tool must be replaced.

When the cutting pitch exceeds 50 μm, it is difficult to reduce the occurrence of interference fringes generated between the liquid crystal panels.

At present, the usual arrangement period (pixel pitch) of the pixels of an electronic display device such as a liquid crystal panel is also about 80 μm, so the above cutting is performed. When the pitch is set to 5 μm to 40 μm, it is half or less of the normal pixel pitch of the pixels of an electronic display device such as a liquid crystal panel.

For example, in the case of using the turning tool 4 having a top end R of 10 mm, the feed pitch F is preferably set between 10 μm and 50 μm, more preferably between 20 μm and 50 μm.

Further, in the case of using the turning tool 4 having a top end R of 5 mm, the feed pitch F is preferably set between 10 μm and 50 μm, more preferably between 15 μm and 40 μm.

The tip radius R and the feed pitch F of the cutting tool are preferably determined such that the theoretical surface roughness Ry is in the range of 1.5 nm to 100 nm, and more preferably the theoretical surface roughness Ry is 5 μ to 60 μ. The way within the scope is determined.

In addition, the theoretical surface roughness Ry is calculated by the following formula (1).

Ry=F ² /8R (1)

(wherein F represents the feed pitch of the cutting tool, and R represents the radius of curvature of the tip of the cutting tool)

When the theoretical surface roughness Ry is set to a value of less than 1.5 nm, the tip radius R and the feed pitch F of the cutting tool are not only shortened the life of the turning tool, but also the appearance of the appearance of the mold is whitened, and the appearance quality is large. Decrease in magnitude. On the other hand, the tip radius R and the feed pitch F of the cutting tool are used with a theoretical surface roughness Ry exceeding 100 nm. In the case of the vanishing effect at the tip of the blade which is important in the aluminum cutting, the deterioration of the surface roughness and the stray defect of the rainbow shape were all caused, and the deterioration of the appearance quality was confirmed.

In the present embodiment, the amount of cut (the x-axis direction in Fig. 1) is set in the range of 0.5 μm to 100 μm. More preferably, it is set between 1 μm and 50 μm, and is preferably set between 1 μm and 20 μm.

When the cutting step is performed, strip-shaped irregularities (cutting marks) corresponding to the turning path of the turning mark, which is called a cut mark having a feed pitch size, are always generated on the surface of the aluminum base material. Therefore, in order to reduce the unevenness of the cut marks, in addition to the cutting, polishing such as buffing, chemical polishing, or electrolytic polishing (etching treatment) may be used in combination.

However, even if the above-described polishing treatment is performed, it is difficult to completely remove the cutting marks, and as shown schematically in FIG. 2, the outer peripheral surface 1a of the aluminum base material 1 which has been completed by mirror processing by cutting or cutting and polishing remains. A strip-shaped uneven structure having a portion of the ridge 1b, the rib 1b extending in a circumferential direction substantially perpendicular to the axis of the cylindrical aluminum base material 1, that is, in the circumferential direction.

The period (pitch P) of the ridges 1b in the axial direction of the cylindrical aluminum base material 1 corresponds to the cutting pitch (feed pitch) and is 5 μm to 50 μm.

In addition, as described above, in the electronic display device such as a liquid crystal panel, the normal arrangement period (pixel pitch) of the pixel is also about 80 μm, so that the cylindrical aluminum base material 1 is convex in the axial direction. The period (pitch P) of the strip 1b is also preferably set to be less than or equal to half the normal pixel pitch of the pixels of an electronic display device such as a liquid crystal panel.

In addition, the aluminum base material sometimes has the oil used in the cutting process, so It is pre-degreased before anodizing.

When a flat aluminum base material is used instead of the cylindrical aluminum base material, the entire surface of the flat aluminum base material is mirror-finished by repeating the following steps: fixing the aluminum base material to the workpiece, and utilizing a step of cutting a aluminum substrate in a strip shape in the X direction by a cutting tool in a sheet processing machine in which the cutting tool moves in the X direction and the Y direction substantially orthogonal to the X direction; and the cutting tool is used in the cutting tool The step of moving at a pitch of 5 μm to 50 μm in the Y direction.

Further, the cutting tool may be moved in the X direction to be cut in a strip shape, and the workpiece may be moved in the Y direction in units of a predetermined pitch.

Step (b):

As shown in (b) of FIG. 3, when the surface portion 10 ((a) in FIG. 3) of the aluminum base material 1 is anodized, the oxide film 14 having the pores 12 is formed.

Examples of the electrolytic solution include sulfuric acid, oxalic acid, phosphoric acid, and the like.

The case of using oxalic acid as the electrolyte:

Specific examples of the case where sulfuric acid is used as the electrolytic solution will be described below. The concentration of oxalic acid is preferably 0.7 M or less. When the concentration of oxalic acid exceeds 0.7 M, the current value may become too high and the surface of the oxide film may become rough.

When the formation voltage is 30 V to 60 V, anodized alumina having a regular high porosity of 100 nm can be obtained. Regardless of whether the formation voltage is higher than the range or lower than the range, there is a tendency for the regularity to decrease.

The temperature of the electrolytic solution is preferably 60 ° C or lower, more preferably 45 ° C or lower. If the temperature of the electrolytic solution exceeds 60 ° C, a phenomenon called "burning" is caused, and sometimes the pores are damaged, or the surface is dissolved and the regularity of the pores is disturbed.

When sulfuric acid is used as the electrolyte:

Specific examples of the case where sulfuric acid is used as the electrolytic solution will be described below. The concentration of sulfuric acid is preferably 0.7 M or less. When the concentration of sulfuric acid exceeds 0.7 M, the current value may become too high to maintain a constant voltage.

When the formation voltage is 25 V to 30 V, anodized alumina having a regular high porosity of 63 nm can be obtained. Regardless of whether the formation voltage is higher than the range or lower than the range, there is a tendency for the regularity to decrease.

The temperature of the electrolytic solution is preferably 30 ° C or lower, more preferably 20 ° C or lower. If the temperature of the electrolytic solution exceeds 30 ° C, a phenomenon called "burning" is caused, and sometimes the pores are damaged, or the surface is dissolved and the regularity of the pores is disturbed.

Step (c):

As shown in (c) of FIG. 3, a part or all of the oxide film 14 is temporarily removed, and this is used as an anodized pore generating point 16, whereby the regularity of the pores can be improved. In other words, in a state in which the oxide film 14 is not completely removed and a part remains, the purpose of removing the oxide film can be achieved as long as the portion of the oxide film 14 which can sufficiently improve the regularity remains.

The method of removing the oxide film is a method of removing the oxide film by dissolving it in a solution which does not dissolve aluminum and selectively dissolves an oxide film. Examples of such a solution include a chromic acid/phosphoric acid mixed solution.

Step (d):

As shown in (d) of Fig. 3, if the aluminum base material from which the oxide film is removed is 10 is anodized again to form an oxide film 14 having cylindrical pores 12.

The anodization may be carried out under the same conditions as in the step (b). The longer the anodization time is, the deeper the pores can be obtained. However, as long as the range of the effect of the step (c) is not lost, the voltage of the anodization in the step (d), the type of the electrolytic solution, the temperature, and the like can be appropriately adjusted.

Step (e):

As shown in (e) of FIG. 3, a process of expanding the pore diameter of the pores 12 (hereinafter referred to as a pore diameter expansion treatment) is performed. The pore diameter enlargement treatment is a treatment of immersing in a solution in which the oxide film is dissolved to expand the pore diameter of the pores obtained by anodization. Examples of such a solution include a phosphoric acid aqueous solution of about 5% by mass.

The longer the pore diameter is enlarged, the larger the pore diameter becomes.

Step (f):

As shown in (f) of FIG. 3, if it is anodized again, a cylindrical hole 12' having a small diameter extending downward from the bottom of the cylindrical pore 12 is further formed.

The anodization may be carried out under the same conditions as in the step (b). The longer the anodization time is, the deeper the pores can be obtained.

Step (g):

When the pore diameter expansion treatment of the step (e) and the anodization of the step (f) are repeated, as shown in (g) of FIG. 3, pores having a shape whose diameter continuously decreases from the opening portion in the depth direction are formed. The oxide film 14 of 12 is obtained on the surface 10 of the aluminum base material 1 with anodized aluminum oxide (aluminum) A mold 18 of a porous oxide film (Alumite). Finally, it is preferred to end with step (e).

The total number of repetitions is preferably 3 or more, more preferably 5 or more. When the number of repetitions is two or less, the diameter of the pores is discontinuously decreased, so that the effect of reducing the reflectance of the moth-eye structure formed using the anodized alumina having such pores is insufficient.

The shape of the pores 12 may be a substantially conical shape, a pyramid shape, a cylindrical shape or the like, and is preferably a conical shape or a pyramid shape. The pore cross-sectional area in the direction orthogonal to the depth direction is continuous from the outermost surface in the depth direction. Reduced shape.

The average spacing between the apertures 12 is below the wavelength of visible light, i.e., below 400 nm. The average spacing between the pores 12 is preferably 20 nm or more.

The average interval between the pores 12 is 50 points measured by an electron microscope observation of the interval between adjacent pores 12 (the distance from the center of the pore 12 to the center of the adjacent pore 12), and the values are averaged. value.

When the average interval is 100 nm, the depth of the pores 12 is preferably from 80 nm to 500 nm, more preferably from 120 nm to 400 nm, and particularly preferably from 150 nm to 300 nm.

The depth of the pores 12 is a value obtained by measuring the distance between the bottommost portion of the pores 12 and the topmost portion of the convex portion existing between the pores 12 when observed by an electron microscope at a magnification of 30,000 times.

The aspect ratio of the pores 12 (the depth of the pores / the average interval between the pores) is preferably from 0.8 to 5.0, more preferably from 1.2 to 4.0, particularly preferably from 1.5 to 3.0.

Thus, a fine uneven structure and a strip shape are formed on the outer peripheral surface. A roller-shaped mold with a concave-convex shape. Using the roll-shaped mold, an elongated optical sheet having a fine uneven structure and a strip-shaped uneven shape transferred onto the surface was produced.

(manufacturing device)

In the optical sheet manufacturing method of the present embodiment, the manufacturing apparatus 20 shown in Fig. 4 is used.

The manufacturing apparatus 20 is provided with the roll-shaped mold 22 which has the fine uneven|corrugated structure on the outer peripheral surface, and the rotation of the roll-form-form- The nip roll 26 is pressed against the outer peripheral surface of the roller-shaped mold 22, and the active energy ray-curable resin composition 28 is supplied to the roller-shaped mold 22 and the elongated substrate. The nozzle 30 between the 24; and the active energy ray irradiation device 32 or the like that irradiates the active energy ray-curable composition 28 with the active energy ray at the downstream side of the nip roller 26.

The grip roller 26 is configured such that the flow side position in the rotation direction of the roller-shaped mold 22 is driven by the air cylinder 34, and the elongated base material 24 is pressed against the outer peripheral surface of the roller-shaped mold 22. Then, the active energy ray-curable composition 28 accommodated in the accumulator 36 is supplied from the nozzle 30 to the elongated substrate 24 in a region where the elongated substrate 24 is pressed against the outer peripheral surface of the roller-shaped mold 22. Between the roller-shaped mold 22.

The active energy ray irradiation device 32 disposed under the roller-shaped mold 22 irradiates the active energy ray-curable resin composition 28 disposed between the substrate 24 and the roller-shaped mold 22 with an active energy ray through the substrate 24 to activate the active energy. The line curable resin composition 28 is cured to form on the substrate 24 The cured resin layer 38 has a shape complementary to the fine uneven structure of the roller-shaped mold 22.

The optical sheet 40 (FIG. 5) on which the cured resin layer 38 is formed on the surface of the substrate 24 is peeled off from the roller-shaped mold 22 by the peeling roller 40.

In the description of the present embodiment, the active energy ray-curable resin composition 28 is disposed between the roller-shaped mold 22 and the substrate 24. However, for the sake of simplicity of description, the state is also referred to as a roller. The state in which the mold 22 is in contact with the substrate 24 is obtained. Further, the active energy ray-curable resin composition 28 may not be disposed between the roller-shaped mold 22 and the substrate 24, and may be formed on the surface of the substrate 24 while being heated by pressing the substrate 24 against the roller-shaped mold 22. A shape complementary to the fine uneven structure.

The substrate 24 is preferably a film or sheet obtained by injection molding, press molding, or the like. The material of the base material 24 is a light transmissive material, and examples thereof include a polycarbonate resin, a polystyrene resin, a polyester resin, a polyurethane resin, an acrylic resin, and a polyether oxime. Polyfluorene, polyether ketone, cellulose resin (such as triethyl fluorene cellulose), polyolefin, alicyclic polyolefin, glass, and the like.

(Active energy ray curable resin composition)

The active energy ray-curable resin composition 28 is a composition containing a polymerizable compound, a polymerization initiator, and an internal mold release agent.

The viscosity of the composition at 25 ° C is preferably 10000 mPa. s below, and then preferably 5000 mPa. Below s, more preferably 2000 mPa. s below. If the composition has a viscosity of 10000 mPa at 25 ° C. s or less, the conformability of the composition to the fine uneven structure becomes good, and the precision can be accurately changed. Printed fine concave and convex structure. The viscosity of the composition was measured at 25 ° C using a rotary E-type viscometer.

(polymerizable compound)

Examples of the polymerizable compound include a monomer having a radical polymerizable bond and/or a cationic polymerizable bond in the molecule, an oligomer, a reactive polymer, and the like.

The monomer having a radical polymerizable bond may, for example, be a monofunctional monomer or a polyfunctional monomer.

The monofunctional monomer may, for example, be methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate or isobutyl (meth)acrylate, ( Dibutyl methacrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, alkyl (meth)acrylate, ( Tridecyl methyl methacrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, (methyl) ) Isobornyl acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, allyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (methyl) (meth) acrylate derivatives such as hydroxypropyl acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate; (meth)acrylic acid, (A) Acrylonitrile; styrene derivatives such as styrene and α-methylstyrene; (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (methyl) Acrylamide, dimethylaminopropyl (meth) acrylamide, etc. (Methyl) acrylamide derivatives and the like. These may be used alone or in combination of two or more.

Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and isocyanuric acid ethylene oxide modified di(methyl). Acrylate, triethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(methyl) Acrylate, 1,5-pentanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, polybutylene glycol di(meth)acrylate, 2,2- Bis(4-(methyl)propenyloxypolyethoxyphenyl)propane, 2,2-bis(4-(methyl)propenyloxyethoxyphenyl)propane, 2,2-double (4-(3-(Methyl)propenyloxy-2-hydroxypropoxy)phenyl)propane, 1,2-bis(3-(methyl)propenyloxy-2-hydroxypropoxy Ethane, 1,4-bis(3-(methyl)propenyloxy-2-hydroxypropoxy)butane, dimethyloltricyclodecane di(meth)acrylate, bisphenol A Ethylene oxide adduct di(meth)acrylate, propylene oxide adduct di(meth)acrylate of bisphenol A, hydroxypivalic acid neopentyl glycol di(meth)acrylate, a difunctional monomer such as divinylbenzene or methylenebis acrylamide; pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide Modified three (Meth) acrylate, trimethylolpropane propylene oxide modified triacrylate, trimethylolpropane oxirane modified triacrylate, isocyanuric acid ethylene oxide modified tris(methyl) Trifunctional monomer such as acrylate; condensation reaction mixture of succinic acid/trimethylolethane/acrylic acid, dipentaerythritol hexa(meth) acrylate, dipentaerythritol penta (meth) acrylate, di-trimethylol A tetrafunctional or higher monomer such as propane tetraacrylate or tetramethylol methane tetra(meth)acrylate; a difunctional or higher urethane acrylate; a difunctional or higher polyester acrylate. These may be used alone or in combination of two or more.

The monomer having a cationically polymerizable bond may, for example, be a monomer having an epoxy group, an oxetanyl group, an oxazoline group, a vinyloxy group or the like, and particularly preferably an epoxy group. Base monomer.

Examples of the oligomer or the reactive polymer include unsaturated polyesters such as a condensate of an unsaturated dicarboxylic acid and a polyhydric alcohol; polyester (meth) acrylate, polyether (meth) acrylate, and polyhydric alcohol ( Methyl) acrylate, epoxy (meth) acrylate, (meth) acrylate urethane, cationically polymerized epoxy compound, homopolymer of the above monomer having a radical polymerizable bond on the side chain Or copolymers, etc.

(polymerization initiator)

In the case of using a photohardening reaction, the photopolymerization initiator may, for example, be benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzil, benzophenone, or the like. Methoxybenzophenone, 2,2-diethoxyacetophenone, α,α-dimethoxy-α-phenylacetophenone, methyl benzhydrazide, ethyl benzhydrazide a carbonyl compound such as 4,4'-bis(dimethylamino)benzophenone or 2-hydroxy-2-methyl-1-phenylpropan-1-one; tetramethylthiuram monosulfide, a sulfur compound such as tetramethylthiuram disulfide; 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, benzamidinediethoxyphosphine oxide or the like. These may be used alone or in combination of two or more.

In the case of using an electron beam hardening reaction, examples of the polymerization initiator include benzophenone, 4,4-bis(diethylamino)benzophenone, and 2,4,6-trimethyl group. Benzophenone, methyl ortho-benzoylbenzoate, 4-phenylbenzophenone, tert-butylhydrazine, 2-ethylhydrazine, 2,4-diethylthioxanthone, isopropyl Thiophenones such as thioxanthone and 2,4-dichlorothioxanthone; diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin Methyl ketal, 1-hydroxycyclohexane Base-phenyl ketone, 2-methyl-2-morpholinyl (4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-? Acetophenone such as phenylphenyl)-butanone; benzoin ether such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; 2,4,6-trimethylbenzhydryldiphenylphosphine Oxide, bis(2,6-dimethoxybenzylidene)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzylidene) a mercaptophosphine oxide such as a phenylphosphine oxide; methyl benzylidenecarboxylate, 1,7-biacridyl heptane, 9-phenyl acridine or the like. These may be used alone or in combination of two or more.

In the case of utilizing a thermosetting reaction, examples of the thermal polymerization initiator include methyl ethyl ketone peroxide, benzamidine peroxide, dicumyl peroxide, tert-butyl hydroperoxide, and hydroperoxide. An organic peroxide such as cumene, tert-butyl peroxyoctanoate, tert-butyl peroxybenzoate or lauric acid; an azo compound such as azobisisobutyronitrile; in the above organic peroxide A redox polymerization initiator which is obtained by combining an amine such as N,N-dimethylaniline or N,N-dimethyl-p-toluidine.

The amount of the polymerization initiator is preferably from 0.1 part by mass to 10 parts by mass per 100 parts by mass of the polymerizable compound. If the amount of the polymerization initiator is less than 0.1 part by mass, polymerization is difficult to proceed. When the amount of the polymerization initiator exceeds 10 parts by mass, the cured film may be colored or the mechanical strength may be lowered.

(internal release agent)

The active energy ray-curable resin composition can improve the continuous transfer property by containing an internal mold release agent.

The internal mold release agent improves the mold release property of the cured product of the active energy ray-curable resin composition and the surface of the mold, and has curable property with active energy rays The composition of the resin composition is not particularly limited in its composition.

Examples of the internal mold release agent include a (poly)oxyalkylalkylphosphoric acid compound, a fluorine-containing compound, an anthrone compound, a compound having a long-chain alkyl group, a polyalkylene wax, a guanamine wax, and a Teflon. Powder (Teflon is a registered trademark) and so on. These may be used alone or in combination of two or more. Among these, a (poly)oxyalkylalkylphosphoric acid compound is preferred as a main component.

By using the (poly)oxyalkylalkylphosphoric acid compound which is the same as the mold release agent as the internal mold release agent, the mold release property of the cured resin layer as a cured product and the mold becomes particularly good. Further, since the load at the time of mold release is extremely low, the fine uneven structure is less damaged, and as a result, the fine uneven structure of the mold can be transferred efficiently and with high precision.

In terms of mold releasability, the (poly)oxyalkylalkylphosphonic acid compound is preferably a compound represented by the following formula (1): (HO) ₃ - _n (O =) P [-O- ( R ₂ O) _m -R ₁ ] _n .........(1)

R ₁ is an alkyl group, R ₂ is an alkylene group, m is an integer of 1 to 20, and n is an integer of 1 to 3.

R _{1 is} preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 3 to 18 carbon atoms.

R _{2 is} preferably an alkylene group having 1 to 4 carbon atoms, more preferably an alkylene group having 2 to 3 carbon atoms.

m is preferably an integer of 1 to 10.

The (poly)oxyalkylalkylphosphoric acid compound may be a monoester (n=1), two Any one of an ester body (n=2) and a triester body (n=3). Further, in the case of a diester or a triester, a plurality of (poly)oxyalkylalkyl groups in one molecule may be different.

Commercial products of the (poly)oxyalkylalkylphosphoric acid compound include, for example, the following.

Manufactured by Chengbei Chemical Co., Ltd.: JP-506H (n≒1~2, m≒1, R ₁ = butyl, R ₂ = extended ethyl), manufactured by Axel: Moldwiz INT -1856 (structure not disclosed), manufactured by Nikko Chemical Co., Ltd.: TDP-10 (n≒3, m≒10, R ₁ = C12~15, R2 = extended ethyl), TDP-8 (n≒3, m≒8 , R ₁ = C12~15, R2 = extended ethyl), TDP-6 (n≒3, m≒6, R ₁ = C12~15, R ₂ = extended ethyl), TDP-2 (n≒3, m≒2, R ₁ = C12~15, R ₂ = extended ethyl), DDP-10 (n≒2, m≒10, R ₁ = C12~15, R ₂ = extended ethyl), DDP-8 ( n≒2, m≒8, R ₁ = C12~15, R ₂ = extended ethyl), DDP-6 (n≒2, m≒6, R ₁ = C12~15, R ₂ = extended ethyl), DDP-4 (n≒2, m≒4, R ₁ = C12~15, R ₂ = extended ethyl), DDP-2 (n≒2, m≒2, R ₁ = C12~15, R ₂ = stretch Ethyl), TLP-4 (n≒3, m≒4, R ₁ = lauryl, R ₂ = exoethyl), TCP-5 (n≒3, m≒5, R ₁ = cetyl, R ₂ = extended ethyl), DLP-10 (n≒3, m≒10, R ₁ = lauryl, R ₂ = extended ethyl).

The (poly)oxyalkylalkylphosphoric acid compound may be used alone or in combination of two or more.

The amount of the (poly)oxyalkylalkylphosphonic acid compound is preferably 0.01% by mass to 1% by mass, more preferably 0.05% by mass based on 100% by mass of the polymerizable compound. The mass % to 0.5% by mass, and more preferably 0.05% by mass to 0.1% by mass. When the amount of the (poly)oxyalkylalkylphosphoric acid compound is 1% by mass or less, the deterioration of the performance of the cured resin layer can be suppressed. Further, it is possible to suppress a decrease in the adhesion to the substrate, and as a result, it is possible to suppress resin residue (de-mold failure) on the mold or peeling of the cured resin layer from the article. When the amount of the (poly)oxyalkylene alkylphosphoric acid compound is 0.01% by mass or more, the mold release property from the mold is sufficient, and resin residue (deformation failure) on the mold can be suppressed.

The active energy ray-curable resin composition may further contain a component which improves mold releasability other than the (poly)oxyalkylalkylphosphoric acid compound in order to further improve the mold release property. Examples of the component include a fluorine-containing compound, an anthrone-based compound, a phosphate-based compound, a compound having a long-chain alkyl group, and a solid wax (polyalkylene wax, guanamine wax, and Teflon powder (Teflon). It is a compound such as a registered trademark).

(other ingredients)

The active energy ray-curable resin composition may optionally contain a non-reactive polymer, an active energy ray sol-gel reactive composition, an antistatic agent, an additive such as a fluorine compound for improving antifouling properties, fine particles, A small amount of solvent.

Examples of the non-reactive polymer include an acrylic resin, a styrene resin, a polyurethane, a cellulose resin, polyvinyl butyral, a polyester, and a thermoplastic elastomer.

The active energy ray sol-gel reactive composition may, for example, be an alkoxydecane compound or an alkyl phthalate compound.

The alkoxydecane compound may, for example, be tetramethoxynonane or tetraisopropoxy Base decane, tetra-n-propoxy decane, tetra-n-butoxy decane, tetra-second butoxy decane, tetra-butoxy decane, methyl triethoxy decane, methyl tripropoxy decane Methyl tributoxy decane, dimethyl dimethoxy decane, dimethyl diethoxy decane, trimethyl ethoxy decane, trimethyl methoxy decane, trimethyl propoxy decane , trimethylbutoxydecane, and the like.

Examples of the alkyl phthalate compound include methyl phthalate, ethyl phthalate, isopropyl phthalate, n-propyl phthalate, n-butyl phthalate, n-pentyl phthalate, and B. Phthalate esters, etc.

The active energy ray irradiation device 32 is preferably a high pressure mercury lamp, a metal halide lamp, a fusion lamp or the like, and the amount of light irradiation energy in this case is preferably from 100 mJ/cm ² to 10000 mJ/cm ² .

(optical sheet)

FIG. 5 is a cross-sectional view schematically showing a configuration of an elongated optical sheet 40 having a fine uneven structure on the surface, which is manufactured by the manufacturing apparatus 20.

The cured resin layer 38 formed on the substrate 24 is a layer containing a cured product of the active energy ray-curable resin composition 28, and has a convex portion 44 which is formed to be fine with the roller-shaped mold 22 on the outer peripheral surface. A shape in which the concave and convex shapes are complementary. Further, the shape of the convex portion 44 is complementary to the shape of the concave portion of the fine uneven structure formed on the outer peripheral surface of the roller-shaped mold 22. In addition, the fine uneven structure is a so-called moth-eye structure in which a plurality of fine convex portions 44 are arranged at intervals of a wavelength of visible light or less.

The shape of the convex portion 44 is preferably a shape in which the cross-sectional area of the convex portion in the direction orthogonal to the height direction continuously increases from the outermost surface in the depth direction, that is, the cross-sectional shape in the height direction of the convex portion is triangular, trapezoidal, or bell-shaped. And other shapes.

The average interval between the convex portions 44 is equal to or less than the wavelength of visible light, that is, 400 nm or less. When a convex portion is formed in a mold using anodized alumina, since the average interval between the convex portions is about 100 nm to 200 nm, it is particularly preferably 250 nm or less.

The average interval of the convex portions 44 is preferably 20 nm or more in terms of ease of formation of the convex portions.

The average interval between the convex portions 44 is a value obtained by measuring the distance between the adjacent convex portions 44 (the distance from the center of the convex portion to the center of the adjacent convex portion) by an electron microscope, and averaging the values.

When the height of the convex portion 44 is 100 nm at an average interval, it is preferably 80 nm to 500 nm, more preferably 120 nm to 400 nm, and particularly preferably 150 nm to 300 nm. When the height of the convex portion is 80 nm or more, the reflectance is sufficiently low, and the wavelength dependence of the reflectance is small. When the height of the convex portion is 500 nm or less, the scratch resistance of the convex portion becomes good.

The height of the convex portion 44 is a value obtained by measuring the distance between the topmost portion of the convex portion and the bottommost portion of the concave portion existing between the convex portions when observed by an electron microscope at a magnification of 30,000 times.

The aspect ratio of the convex portion 44 (the height of the convex portion/the average interval between the convex portions) is preferably 0.8 to 5.0, more preferably 1.2 to 4.0, and particularly preferably 1.5 to 3.0. When the aspect ratio of the convex portion is 1.0 or more, the reflectance is sufficiently lowered. When the aspect ratio of the convex portion is 5.0 or less, the scratch resistance of the convex portion is improved.

The difference between the refractive index of the cured resin layer 38 and the refractive index of the substrate 24 is preferably 0.2 or less, more preferably 0.1 or less, and particularly preferably 0.05 or less. When the refractive index difference is 0.2 or less, the boundary between the cured resin layer 38 and the substrate 24 can be suppressed. Reflection on the surface.

When it is known that the surface has a fine concavo-convex structure, if the surface is formed of a hydrophobic material, the super-water-repellent property can be obtained by the lotus effect, and if the surface is formed of a hydrophilic material, Super hydrophilicity is obtained.

When the material of the cured resin layer 38 is hydrophobic, the water contact angle of the surface of the fine uneven structure is preferably 90 or more, more preferably 110 or more, and particularly preferably 120 or more. When the water contact angle is 90 or more, the water stain is less likely to adhere, so that sufficient antifouling properties can be exhibited. In addition, since water is not easily adhered, it is expected to prevent icing.

When the material of the cured resin layer 38 is hydrophilic, the water contact angle of the surface of the fine uneven structure is preferably 25 or less, more preferably 23 or less, and particularly preferably 21 or less. When the water contact angle is 25 or less, the dirt adhering to the surface can be washed with water, and the oil stain is less likely to adhere, so that sufficient antifouling properties can be exhibited. The water contact angle is preferably 3° or more in terms of suppressing deformation of the fine concavo-convex structure due to water absorption of the hardened resin layer 38 and an accompanying increase in reflectance.

As described above, the strip-shaped unevenness including the ridge-like portion as the cutting mark remains on the outer circumferential surface of the roller-shaped mold 22, so that the strip-shaped uneven shape including the ridge-like portion is also reverse-transferred to hardening. On the resin layer 38. Further, although the strip-shaped unevenness is not normally observed, if the light-emitting diode (LED) light source having high directivity is used from the back surface of the optical sheet 40, observation by transmitted light is slightly observed. To.

However, the pitch of the ridges 1b of the outer peripheral surface of the roller-shaped mold 22 is 5 Since μm is 50 μm, the pitch of the strip-like unevenness which is reversely transferred to the cured resin layer 38 is also 5 μm to 50 μm.

As described above, the current arrangement period (pixel pitch) of the pixels of an electronic display device such as a liquid crystal panel is at least about 80 μm, so that the pitch of the strip-shaped unevenness which is reversely transferred to the cured resin layer 38 is also It is 5 μm to 50 μm, and is half or less of the normal pixel pitch of a pixel of an electronic display device such as a liquid crystal panel.

In an electronic display device, a pixel point is vertically and horizontally arranged at a predetermined dot pitch of about 100 μm to 300 μm, and an optical sheet having a pattern parallel to the arrangement of pixel points is disposed thereon. , it is easy to produce interference images.

However, in the optical sheet of the present embodiment, the arrangement pitch of the strip-shaped uneven shapes is in the range of 5 μm to 50 μm, and is extremely small compared with the dot pitch of the display device or the like. Therefore, the present invention is used in an electronic display device. In the case of the optical sheet of the invention, it is possible to suppress the occurrence of an interference image or to be very small even if it is not easily seen. Therefore, the optical sheet of the present invention can be preferably used as an antireflection film for an electronic display device which is disposed on the surface of an electronic display device such as a liquid crystal display device or an organic EL (Organic Electro-Luminescence).

In addition, the period of the pixel point of the electronic display device differs depending on the electronic display device. However, if the pitch of the ridges 1b on the outer circumferential surface of the roller-shaped mold 22 is less than or equal to half the dot pitch of the electronic display device, generation can be suppressed. Interference image. In the above description, the case where the pitch of the ridges 1b on the outer circumferential surface of the roller-shaped mold 22 is 5 μm to 50 μm or less has been described. However, as described above, the pixels of an electronic display device such as a liquid crystal panel are generally used. of The arrangement period (pixel pitch) is also at least about 80 μm, so the pitch of the ridges 1b is less than or equal to half the period of the pixel point of the electronic display device.

Therefore, since the period of the pixel point of the electronic display device differs depending on the electronic display device, if the pitch of the ridge 1b is sufficiently reduced in advance, an electronic display device applicable to most electronic display devices can be manufactured. Use an anti-reflection film. In this regard, the pitch of the ridges 1b on the outer circumferential surface of the roller-shaped mold 22 is preferably set to 5 μm or more, and is preferably set to 50 μm or less, and more preferably set to 40 μm or less. The optimum setting is 30 μm or less.

Further, the cycle of the pixel point of the electronic display device is not limited to the current numerical value. Therefore, in the present embodiment, the cutting pitch is appropriately changed so that the pitch of the ridge 1b becomes half or less of the period of the pixel point of the electronic display device.

Further, the antireflection film for an electronic display device according to the present invention can be disposed on one side or both sides of a protective plate or a front panel of a display device, or a member such as a touch panel disposed on a display device. However, since the member disposed apart from the display device is less likely to generate an interference image with the pixel of the display device, when the optical sheet according to the present invention is used as an antireflection film for an electronic display device, it is preferably attached to Used on the surface of the display device.

[Example] (Example 1)

When making a roller-shaped mold, prepare an aluminum base material with a diameter of 200 mm and a width of 320 mm. The roller-shaped aluminum base material is a processor that uses a shaft for performing a chuck at both ends and performs deformation without causing machining by a lathe.

Then, the contact portion of the shaft portion of the roller-shaped aluminum base material as a reference is set to be 5 μm or less in a precision lathe.

Then, a single crystal diamond turning tool having a top end of 5 mm was prepared, and it was confirmed by a microscope that the tip of the turning tool was not abnormal, and then mounted on a precision lathe. In the state where the roller was rotated at a speed of 1000 rpm, a 10 μm cut was performed, and the surface of the aluminum base material was mirror-cut at a feed cutting pitch of 10 μm per revolution.

In order to improve the cooling and lubrication of the processed portion, the cutting oil is supplied to the rake face and the relief face of the diamond turning tool in a mist form and processed. Further, the generated chips are placed on the unmachined side of the mirror surface processing, and the generated chips are discharged in parallel.

The aluminum base material subjected to mirror processing was subjected to visual inspection using linear light in a dark room, and as a result, a mirror-finished roller having an aesthetically pleasing appearance was produced. The theoretical surface roughness Ry at this time was 2.5 nm.

Then, the aluminum base material subjected to the mirror surface processing was subjected to the following treatment to form a fine uneven shape on the surface.

(a) Steps:

The aluminum plate was anodized in a 0.3 M aqueous solution of oxalic acid under the conditions of a direct current of 40 V and a temperature of 16 ° C for 30 minutes.

(b) Steps:

The aluminum plate on which the oxide film was formed in the above step was immersed in a 6 mass% phosphoric acid/1.8 mass% chromic acid mixed aqueous solution for 6 hours to remove the oxide film.

(c) Steps:

The aluminum plate was anodized in a 0.3 M aqueous solution of oxalic acid under the conditions of a direct current of 40 V and a temperature of 16 ° C for 30 seconds.

(d) Steps:

The aluminum plate on which the oxide film was formed in the above step was immersed in 5 mass% phosphoric acid at 32 ° C for 8 minutes to carry out a pore diameter expansion treatment.

(e) Steps:

The above steps (c) and (d) were recombined five times to obtain an anodized porous alumina having a substantially conical shape having a period of 100 nm and a depth of 180 nm.

The obtained anodized porous alumina was washed with deionized water, and then the surface water was removed by air flow, and fluorine was used by using a diluent (manufactured by Harves, trade name HD-ZV). The release material (manufactured by Daikin Industries, Ltd., trade name: Optools DSX) was immersed for 10 minutes in a solution obtained by diluting the solid content to 0.1% by mass, and air-dried for 20 hours to obtain pores formed on the surface. Roller mold.

When the obtained roller-shaped mold was irradiated with light having high directivity from the LED light source, a strip-like uneven structure having a pitch of 20 μm was slightly confirmed.

An ultraviolet curable resin composition was poured into the pore surface of the roll-shaped mold, and the base film was pushed over while being covered. The resin composition was cured by irradiating ultraviolet rays with an energy of 2000 mJ/cm ² from the substrate film side using a high pressure mercury lamp. Thereafter, the base film and the cured resin composition were peeled off from the roller-shaped mold to obtain an optical sheet having a fine uneven structure on the surface.

On the surface of the optical sheet, a strip-shaped uneven structure and a fine uneven structure of a roller-shaped mold are transferred, and a strip-shaped uneven structure having a pitch of 10 μm as shown in FIG. 5 and an interval of adjacent convex portions 46 are formed. A substantially conical nano-concave structure of 100 nm and a height of the convex portion 46 of 180 nm.

The optical sheet was cut into a rectangular shape to obtain a rectangular optical film. At this time, the optical sheet is cut in such a manner that the strip-shaped uneven structure is parallel to at least one side of the rectangular shape.

Then, a rectangular optical film was placed on a liquid crystal cell having a cell pitch of 180 μm, incorporated into the backlight unit, and lit, and as a result, a good appearance in which interference fringes were not obtained was obtained.

(Example 2)

The same roller-shaped mold as in Example 1 was placed in a precision lathe, and the single crystal diamond turning tool for processing was prepared to have a tip R of 15 mm. After confirming that there is no abnormality at the top of the turning tool by the microscope, it is mounted on a precision lathe. In the state where the roller was rotated at a speed of 1000 rpm, a cutting of 10 μm was performed, and the surface of the aluminum base material was mirror-cut at a feed cutting pitch of 50 μm per revolution. The theoretical surface roughness Ry at this time was 20.8 nm.

After the mirror processing, the visual inspection of the mold itself was carried out using linear light in a dark room, and as a result, a mirror-finished roller having an aesthetically pleasing appearance was produced.

Further, an anodizing treatment and a forming operation were carried out in the same manner as in Example 1 to obtain an optical sheet web. In the optical sheet, the optical sheet is cut in such a manner that the strip-shaped uneven structure is parallel to at least one side of the rectangular shape, and the rectangular optical film is placed on the liquid crystal cell having a cell pitch of 180 μm, and is assembled to The backlight unit is lit and the result is that a good appearance without interference fringes can be obtained.

(Example 3)

The same roller-shaped mold as in Example 1 was placed in a precision lathe, and the single crystal diamond turning tool for processing was prepared to have a tip R of 2 mm. After confirming that there is no abnormality at the top of the turning tool by the microscope, it is mounted on a precision lathe. In the state where the roller was rotated at a speed of 1000 rpm, a 10 μm cut was performed, and the surface of the aluminum base material was mirror-cut at a feed cutting pitch of 30 μm per revolution. The theoretical surface roughness Ry at this time was 56.25 nm.

After the mirror processing, the visual inspection of the mold itself was carried out using linear light in a dark room, and as a result, a mirror-finished roller having an aesthetically pleasing appearance was produced.

Further, an anodizing treatment and a forming operation were carried out in the same manner as in Example 1 to obtain an optical sheet web. In the optical sheet, the optical sheet is cut in such a manner that the strip-shaped uneven structure is parallel to at least one side of the rectangular shape, and the rectangular optical film is placed on the liquid crystal cell having a cell pitch of 180 μm, incorporated into the backlight unit and lit. As a result, a good appearance in which interference fringes are not obtained can be obtained.

(Example 4)

The same roller-shaped mold as in Example 1 was placed in a precision lathe, and the single crystal diamond turning tool for processing was prepared to have a tip R of 100 mm. After confirming that there is no abnormality at the top of the turning tool by the microscope, it is mounted on a precision lathe. In the state where the roller was rotated at a speed of 1000 rpm, a 10 μm cut was performed, and the surface of the aluminum base material was mirror-cut at a feed cutting pitch of 100 μm per revolution. The theoretical surface roughness Ry at this time was 12.5 nm.

After the mirror processing, the visual inspection of the mold itself was carried out using linear light in a dark room, and as a result, a mirror-finished roller having an aesthetically pleasing appearance was produced.

Further, an anodizing treatment and a forming operation were carried out in the same manner as in Example 1 to obtain an optical sheet web. In the optical sheet, the optical sheet is cut in such a manner that the strip-shaped uneven structure is parallel to at least one side of the rectangular shape, and the rectangular optical film is placed on the liquid crystal cell having a cell pitch of 180 μm, incorporated into the backlight unit and lit. As a result, an abnormality in appearance was not confirmed except that a significant interference pattern was confirmed.

(Comparative Example 1)

The same operation as in Example 1 was carried out except that the cutting pitch was set to 200 μm.

The obtained rectangular optical sheets were placed on a liquid crystal cell having a cell pitch of 180 μm, incorporated into a backlight unit, and lit, and as a result, significant interference fringes were confirmed. The theoretical surface roughness Ry at this time was 333.3 nm.

(Comparative Example 2)

The same operation as in Example 2 was carried out except that the cutting pitch was set to 5 μm. As a result, the appearance of the mold was completely whitened, and it became a state in which it could not be used as a mold. The theoretical surface roughness Ry at this time was 0.21 nm.

(Comparative Example 3)

The same roller-shaped mold as in Example 1 was placed in a precision lathe, and the single crystal diamond turning tool for processing was prepared to have a tip R of 2 mm. After confirming that there is no abnormality at the top of the turning tool by the microscope, it is mounted on a precision lathe. In the state where the roller was rotated at a speed of 1000 rpm, a cutting of 10 μm was performed, and the surface of the aluminum base material was mirror-cut at a feed cutting pitch of 50 μm per revolution. The theoretical surface roughness Ry at this time was 156.3 nm.

After mirror processing, linear light is used in the dark room to implement the mold itself. As a result of the inspection, it was confirmed that the interference pattern was not observed. However, the rainbow-like streaks were generated in an all-round manner, and it was in a state incapable of being used as a mirror-finished roller.

1‧‧‧Aluminum base metal

1a‧‧‧outer surface

1b‧‧‧ ribs

2‧‧‧Rotating mechanism

4‧‧‧ turning tools

6‧‧‧ platform

10‧‧‧Surface

12, 12'‧‧‧ pores

14‧‧‧Oxide film

16‧‧‧Pore generation points

18‧‧‧Mold

20‧‧‧ Manufacturing equipment

22‧‧‧Roller mould

24‧‧‧Substrate

26‧‧‧Clamping roller

28‧‧‧Active energy ray-curable resin composition

30‧‧‧Nozzles

32‧‧‧Active energy line irradiation device

34‧‧‧Air cylinder

36‧‧‧ storage tank

38‧‧‧ hardened resin layer

40‧‧‧Optical sheet

42‧‧‧ peeling roller

44‧‧‧ convex

P‧‧‧ Arrangement cycle

Fig. 1 is a view for explaining a cutting process of an aluminum base material when a roll-shaped mold for producing an optical sheet according to a preferred embodiment of the present invention is produced.

Fig. 2 is a view schematically showing the configuration of a roll-shaped mold for producing an optical sheet according to another preferred embodiment of the present invention.

Fig. 3 is a schematic cross-sectional view showing a step of producing an anodized alumina having a fine uneven structure on the surface of a roll-shaped mold.

FIG. 4 is a configuration diagram schematically showing an example of a manufacturing apparatus of an optical sheet having a fine uneven structure on the surface.

Fig. 5 is a view schematically showing a cross-sectional structure of an optical sheet having a fine uneven structure on its surface.

1‧‧‧Aluminum base metal

1a‧‧‧outer surface

1b‧‧‧ ribs

P‧‧‧ Arrangement cycle

Claims (5)

A method for producing an optical sheet manufacturing mold, which is a method for producing an optical sheet manufacturing mold having a fine uneven structure on a surface and transferring the fine uneven structure on the surface onto a sheet to form an optical sheet And characterized in that it comprises: a mirror finishing step of cutting a surface of the aluminum base material at a predetermined feed pitch, mirror-finishing the surface of the aluminum base material; and forming a fine uneven structure on the aluminum base material The surface is anodized to form a fine uneven structure; and in the mirror processing step, when the feed pitch of the cutting tool is set to F and the radius of curvature of the tip of the cutting tool is set to R, the following The aluminum base material is cut so that the value of Ry represented by the formula (1) is 1.5 nm or more and 100 nm or less, and Ry=F ² /8R (1). The method for producing a mold for producing an optical sheet according to claim 1, wherein the feed pitch of the cutting tool is 5 μm or more and 50 μm or less. An optical sheet manufacturing method using the mold manufactured by the manufacturing method according to claim 1, wherein the optical sheet manufacturing method includes a transfer step of bringing the sheet into contact with the mold. a surface on which the shape of the surface is transferred onto the sheet to form an optical sheet material. An electronic display device comprising an optical sheet manufactured by the manufacturing method according to claim 3 of the patent application. A mirror surface processing method which is a mirror surface processing method of an aluminum base material, wherein the aluminum base material is used to form a fine uneven structure on a surface thereof, and is used for transferring the fine uneven structure to a sheet to manufacture an optical sheet. The base material of the optical sheet manufacturing mold, wherein the mirror surface processing method includes: a cutting step of cutting a surface of the aluminum base material at a predetermined feed pitch; and in the cutting step, the cutting wheel is used When the above-described feed pitch of the knives is set to F and the radius of curvature of the tip end of the cutting tool is set to R, the aluminum mother is performed so that the value of Ry represented by the following formula (1) is 1.5 nm or more and 100 nm or less. Cutting of the material, Ry = F ² / 8R (1).