WO2017065090A1

WO2017065090A1 - Base material surface treatment method and mold production method

Info

Publication number: WO2017065090A1
Application number: PCT/JP2016/079828
Authority: WO
Inventors: 林　秀和; 信明山田; 洋合田; 寺下　慎一
Original assignee: シャープ株式会社
Priority date: 2015-10-14
Filing date: 2016-10-06
Publication date: 2017-04-20
Also published as: JPWO2017065090A1; JP6626898B2; CN108138331A; CN108138331B

Abstract

This method for treating the surface of a columnar or tubular base material (12) comprises: (a) a step of allowing the base material to rotate around the long axis of the base material in a state in which the base material is disposed so that the major axis direction of the base material is substantially parallel to the horizontal direction; and (b) a step of allowing a part of the outer circumferential surface of the base material to contact with a first etching solution (E1) contained in a first etching tank (51).

Description

Substrate surface treatment method and mold production method

The present invention relates to a substrate surface treatment method and a mold manufacturing method. The “mold” here includes molds used in various processing methods (stamping and casting), and is sometimes referred to as a stamper. It can also be used for printing (including nanoprinting).

2. Description of the Related Art An optical element such as a display device or a camera lens used for a television or a mobile phone is usually provided with an antireflection technique in order to reduce surface reflection and increase light transmission. For example, when light passes through the interface of a medium with a different refractive index, such as when light enters the interface between air and glass, the amount of transmitted light is reduced due to Fresnel reflection, etc., and visibility is reduced. is there.

In recent years, attention has been focused on a method of forming a micro uneven pattern on the substrate surface, in which the period of the unevenness is controlled to be not more than the wavelength of visible light (λ = 380 nm to 780 nm) as an antireflection technique (see Patent Documents 1 to 3). reference). The two-dimensional size of the convex portions constituting the concavo-convex pattern exhibiting the antireflection function is 10 nm or more and less than 500 nm. Here, the “two-dimensional size” of the convex portion refers to the area equivalent circle diameter of the convex portion when viewed from the normal direction of the surface. For example, when the convex portion has a conical shape, The two-dimensional size corresponds to the diameter of the bottom surface of the cone. The same applies to the “two-dimensional size” of the recess.

This method utilizes the principle of a so-called moth-eye structure, and the refractive index for light incident on the substrate is determined from the refractive index of the incident medium along the depth direction of the irregularities. By continuously changing the refractive index, reflection in the wavelength region where reflection is desired to be prevented is suppressed.

The moth-eye structure has an advantage that it can exhibit an antireflection effect with a small incident angle dependency over a wide wavelength range, can be applied to many materials, and can form an uneven pattern directly on a substrate. As a result, a low-cost and high-performance antireflection film (or antireflection surface) can be provided.

The present applicant has developed a method using an anodized porous alumina layer obtained by anodizing aluminum as a method for producing an antireflection film (or antireflection surface) having a moth-eye structure (Patent Documents 2 and 3). ).

By using the anodized porous alumina film, a mold for forming a moth-eye structure on the surface (hereinafter referred to as “moth-eye mold”) can be easily manufactured. In particular, as described in Patent Documents 2 and 3, if the surface of the anodized aluminum film is used as a mold as it is, the effect of reducing the manufacturing cost is great. The surface structure of the moth-eye mold that can form the moth-eye structure is referred to as an “inverted moth-eye structure”.

Further, as described in Patent Documents 1 to 4, in addition to the moth-eye structure (microstructure), an uneven structure (macrostructure) larger than the moth-eye structure is provided, so that the antireflection film (antireflection surface) is provided. An anti-glare (anti-glare) function can be imparted. The two-dimensional size of the convex part or the concave part constituting the concavo-convex structure exhibiting the anti-glare function (sometimes referred to as “anti-glare structure”) is 200 nm or more and less than 100 μm. The surface structure of the mold that can form an antiglare structure is referred to as an “inverted antiglare structure”. The entire disclosure of Patent Documents 1 to 4 is incorporated herein by reference.

In this specification, the unevenness constituting the moth-eye structure (or inverted moth-eye structure) is referred to as micro unevenness, and the unevenness constituting the antiglare structure (or inverted antiglare structure) is referred to as macro unevenness. To. The range of the two-dimensional size of the macro unevenness partially overlaps the range of the two-dimensional size of the micro unevenness, but in the antireflection film (antireflection surface) having the antiglare function, the antiglare The concavo-convex structure constituting the structure is larger than the concavo-convex structure constituting the moth-eye structure that exhibits the antireflection function.

JP-T-2001-517319 Special Table 2003-531962 International Publication No. 2011/055757 International Publication No. 2013/146656

Various methods are being sought for a method for efficiently producing a mold for forming an antireflection film (or antireflection surface) having an appropriate antiglare function.

For example, in the sandblasting method described in Patent Document 1, it is difficult to form a desired macro uneven structure imparting an antiglare function with good reproducibility. Further, in the cathode electrolysis method described in Patent Document 3, there may be a case where a macro uneven structure capable of sufficiently exhibiting the antiglare function cannot be formed.

Furthermore, the surface reflecting the continuous macro uneven structure without the flat portion of the resin layer formed by electrodeposition described in Patent Document 4 has a problem that the image is blurred. In recent years, with the progress of high definition display devices, there is a demand for an antireflection film having an appropriate antiglare function in which blurring of an image is suppressed.

The present inventor examined a method of manufacturing an antireflection film (or antireflection surface) having an appropriate antiglare function and an appropriate specular reflectivity by a roll-to-roll method. The present inventors have found that it is difficult to uniformly form an inverted antiglare structure on the surface. This problem is a common problem in the technique of treating the surface of a columnar or cylindrical substrate.

An object of the present invention is to provide a method that can uniformly treat the surface of a columnar or cylindrical substrate.

A surface treatment method for a substrate according to an embodiment of the present invention is a method for treating the surface of a columnar or cylindrical substrate, and (a) the major axis direction of the substrate is substantially parallel to the horizontal direction. In the state where the base material is arranged as described above, the step of rotating the base material around the long axis of the base material, and (b) a part of the outer peripheral surface of the base material is accommodated in the first etching tank. And contacting with the first etching solution.

In one embodiment, the method further includes a step (c) of spraying a second etching solution, which is the same as the first etching solution, on the outer peripheral surface of the substrate.

In one embodiment, the step (c) is performed simultaneously with the step (b), and the second etching solution is a portion of the outer peripheral surface of the substrate that is in contact with the first etching solution. It is sprayed in the vicinity.

In one embodiment, the step (c) is performed simultaneously with the step (a), and the second etching solution is a portion of the outer peripheral surface of the substrate that is in contact with the first etching solution. It is sprayed to a portion that is in the vicinity and is rotating away from the first etching solution in the step (a).

In one embodiment, in the step (c), an angle at which the second etching solution is ejected is inclined by 45 ° or more and less than 90 ° from the vertical direction.

In one embodiment, the base material is an aluminum base material formed of an Al—Mg—Si based aluminum alloy and subjected to mechanical mirror finishing.

In one embodiment, the first etching solution is an aqueous solution containing a salt of hydrogen fluoride and ammonium.

In one embodiment, the salt of hydrogen fluoride and ammonium is ammonium fluoride.

In one embodiment, before the step (b), the method further includes a step (b1) of bringing a part of the outer peripheral surface of the base material into contact with a third etching solution different from the first etching solution. The etching rate of the 3 etching solution with respect to the outer peripheral surface of the substrate is lower than the etching rate of the first etching solution with respect to the outer peripheral surface of the substrate.

In one embodiment, the third etching solution is an etching solution obtained by diluting the first etching solution.

In one embodiment, the third etching solution is at a lower temperature than the first etching solution.

In one embodiment, the third etching solution is contained in a second etching tank different from the first etching tank.

In one embodiment, the third etching solution is contained in the first etching tank.

In one embodiment, after the step (b), the method further includes a step (b2) of bringing a part of the outer peripheral surface of the base material into contact with a fourth etching solution different from the first etching solution. The etching rate of the etching solution with respect to the outer peripheral surface of the substrate is lower than the etching rate of the first etching solution with respect to the outer peripheral surface of the substrate.

In one embodiment, the fourth etching solution is the same etching solution as the third etching solution.

In one embodiment, in the step (a), the peripheral speed of the base material is more than 0 m / s and not more than 0.03 m / s.

In one embodiment, in the step (a), the rotation speed of the substrate is more than 0 rpm and not more than 2 rpm.

A mold manufacturing method according to an embodiment of the present invention includes: (A) a cylindrical aluminum substrate formed of an Al—Mg—Si-based aluminum alloy, which has been subjected to mechanical mirror finishing (B) a step of treating the surface of the aluminum substrate by any one of the above surface treatment methods, and (C) after the step (B), the surface of the aluminum substrate. Forming a mold base by forming an inorganic material layer and forming an aluminum film on the inorganic material layer; and (D) after the step (C), the surface of the aluminum film is an anode. A step of forming a porous alumina layer having a plurality of micro-recesses by oxidation; and (E) after the step (D), the porous alumina layer is brought into contact with an etching solution. A step of enlarging the plurality of micro concave portions of the porous alumina layer, and (F) a step of growing the plurality of micro concave portions by further anodizing after the step (E). .

In one embodiment, before the step (B), the method further includes a step (G) of etching the surface of the aluminum base using an alkaline etching solution.

In one embodiment, the alkaline etching solution has a pH of 8 or more and 10 or less.

In one embodiment, the alkaline etching solution is prepared by adding an acidic additive to an aqueous solution containing an organic compound having an amino group.

In one embodiment, the volume of the acidic additive is 5% or more with respect to the volume of the aqueous solution containing the organic compound having an amino group.

The mold according to the embodiment of the present invention is a mold manufactured by any one of the mold manufacturing methods described above.

The mold according to another embodiment of the present invention includes a plurality of convex portions having a two-dimensional size of 200 nm to 30 μm when viewed from the normal direction of the surface, and 2 when viewed from the normal direction of the surface. A porous alumina layer having a surface structure having a plurality of micro concave portions having a dimensional size of 10 nm or more and less than 500 nm.

An antireflection film manufacturing method according to an embodiment of the present invention includes a step of preparing any of the above molds, a step of preparing a workpiece, and photocuring between the mold and the surface of the workpiece. A step of curing the photocured resin by irradiating the photocured resin with light in a state where a resin is applied; and a step of peeling the anti-reflective film formed of the photocured resin cured of the mold; Is included.

The antireflection film according to the embodiment of the present invention is an antireflection film manufactured by the above-described method for manufacturing an antireflection film.

According to the embodiment of the present invention, the surface of a columnar or cylindrical substrate can be treated evenly.

(A)-(d) is typical sectional drawing for demonstrating the manufacturing method of the mold 100 for moth eyes by embodiment of this invention, (a) is the aluminum base material 12 of the mold 100 for moth eyes. It is typical sectional drawing, (b) is sectional drawing which shows typically the surface structure of the aluminum base material 12 which has the inverted anti-glare structure, (c) is inorganic on the surface of the aluminum base material 12 It is typical sectional drawing of the mold base material 10 in which the material layer 16 and the aluminum film | membrane 18 were formed, (d) is the inverted anti-glare structure and the inverted moth-eye structure superimposed on the inverted anti-glare structure. 1 is a schematic cross-sectional view of a moth-eye mold 100 having (A) is a schematic plan view of an inverted antiglare structure, and (b) is a schematic perspective view of the inverted antiglare structure. It is a figure for demonstrating the manufacturing method of the anti-reflective film using the type | mold 100 for moth eyes. (A) ~ (c) is a schematic diagram of an antireflection film having an antiglare function according to an embodiment of the present invention, (a) is a schematic diagram when the surface of the antireflection film is observed from the vertical direction, (B) is a schematic diagram when the surface of an antireflection film is observed from an oblique direction, and (c) is a schematic diagram of a cross section of the antireflection film. (A) And (b) is a schematic diagram for demonstrating the surface treatment method of the base material by embodiment of this invention. (A) is a schematic diagram for demonstrating the surface treatment method of the base material by a comparative example, (b) is manufactured by the manufacturing method of the type | mold using the surface treatment method of the base material by a comparative example. 4 is a schematic plan view when the antireflection film 32 manufactured using the moth-eye mold 100 is observed from the normal direction of the antireflection film 32. FIG. (A) is typical when the antireflection film 32 manufactured using the moth-eye mold 100 manufactured by the mold manufacturing method according to the embodiment of the present invention is observed from the normal direction of the antireflection film 32. FIG. 4B is a schematic diagram for explaining a process of performing a matte treatment on the surface of the aluminum substrate 12 in the process of manufacturing the moth-eye mold 100, and is a cylindrical aluminum substrate. It is the schematic diagram seen from 12 major axis directions. (A) And (b) is a schematic diagram for demonstrating the surface treatment method of the base material by embodiment of this invention. (A) And (b) is a schematic diagram for demonstrating the surface treatment method of the base material by embodiment of this invention. (A) is a schematic diagram for demonstrating the surface treatment method of the base material by embodiment of this invention, (b) is the length of the aluminum base material 12 produced in the outer peripheral surface of the aluminum base material 12 It is a schematic diagram for demonstrating the some stripe-shaped nonuniformity extended in the direction substantially orthogonal to an axial direction, (c) And (d) is a model for demonstrating the angle from which the etching liquid for spraying is ejected. It is a typical figure. (A) And (b) is a figure which shows the optical image of the aluminum base material 12, (a) is a satin finish by the surface treatment method which does not include the process of spraying the etching liquid for spraying on the outer peripheral surface of the aluminum base material 12. (B) is an aluminum substrate 12 that has been subjected to a satin treatment by a surface treatment method that includes a step of spraying a spraying etchant onto the outer peripheral surface of the aluminum substrate 12. . (A) to (d) are the surfaces of an aluminum substrate having an inverted antiglare structure formed by the matte treatment process of Experimental Example 1-1, Experimental Example 2-1, Experimental Example 3-1 and 4-1. Is a diagram showing optical microscope images (50 times) when observed from the vertical direction, (e) to (h) are Experimental Example 1-1, Experimental Example 2-1, Experimental Example 3-1 and 4- It is a figure which shows the SEM image (full scale 20 micrometers in a SEM image) when the surface of the anti-glare film | membrane formed from the aluminum base material of 1 is observed from a perpendicular direction. (A) to (e) are inverted antiglare formed by the satin treatment process of Experimental Example 1-2, Experimental Example 1-3, Experimental Example 2-2, Experimental Example 3-2 and Experimental Example 4-2. It is a figure which shows an optical microscope image (50 time) when the surface of the aluminum base material which has a structure is observed from a perpendicular direction. (A) to (d) are optical microscopic images when the surface of an aluminum substrate having an inverted antiglare structure formed by the satin treatment process of Experimental Examples 5-1 to 5-4 is observed from the vertical direction ( (E) and (f) are SEM images when the surface of the antiglare film formed from the aluminum base material of Experimental Examples 5-3 and 5-4 is observed from the vertical direction ( It is a figure which shows the full scale 20micrometer in a SEM image. (A) and (b) are optical microscopic images when the surface of an aluminum substrate having an inverted antiglare structure formed by the satin treatment process of Experimental Examples 6-1 and 6-2 is observed from the vertical direction ( 50 times). (A) is a view showing an optical microscope image (50 ×) when the surface of the aluminum base material subjected to the alkali cleaning step in Experimental Example 7-1 is observed from the vertical direction, and (b) and (c) ) Is a diagram showing an SEM image (full scale 20 μm in the SEM image) when the surface of the polymer film formed from the aluminum base material of Experimental Examples 7-1 and 7-2 is observed from the vertical direction. (A) to (d) are optical microscopic images when the surface of an aluminum substrate having an inverted antiglare structure formed by the satin treatment process of Experimental Examples 8-1 to 8-4 is observed from the vertical direction ( (E) to (h) are SEM images when the surface of the polymer film formed from the aluminum base material in Experimental Examples 8-1 to 8-4 is observed from the vertical direction. It is a figure which shows (full scale 20micrometer in a SEM image). (A) to (d) are optical microscopic images when the surface of an aluminum substrate having an inverted antiglare structure formed by the satin treatment process of Experimental Examples 9-1 to 9-4 is observed from the vertical direction ( 50 times). (A) to (d) are optical microscope images when the surface of an aluminum substrate having an inverted antiglare structure formed by the matte treatment process of Experimental Examples 10-1 to 10-4 is observed from the vertical direction ( (E) to (h) are SEM images when the surface of the polymer film formed from the aluminum base material of Experimental Examples 10-1 to 10-4 is observed from the vertical direction. It is a figure which shows (full scale 20micrometer in a SEM image). (A) is a figure which shows the relationship between the time of an alkali cleaning process, and the mass change rate of an aluminum base material, (b) is the antiglare obtained by using the time of an alkali cleaning process and an aluminum base material as a type | mold. It is a figure which shows the relationship with the haze value of a film | membrane. (A) and (b) are optical microscopic images when the surface of an aluminum substrate having an inverted antiglare structure formed by the satin treatment process of Experimental Examples 11-1 and 11-2 is observed from the vertical direction ( (C) and (d) are SEM images when the surface of the polymer film formed from the aluminum base material of Experimental Examples 11-1 and 11-2 is observed from the vertical direction. It is a figure which shows (full scale 20micrometer in a SEM image). (A) And (b) is a figure which shows typically the relationship of the magnitude | size of the macro uneven | corrugated structure for forming the conventional anti-glare structure, and the dot pitch Px of a row direction. (A) It is sectional drawing which shows typically the structure of a macro unevenness | corrugation for forming the conventional anti-glare structure, (b) is a typical cross section which shows the inverted moth eye structure superimposed on the macro unevenness | corrugation (C) is a schematic cross-sectional view enlarging an inverted moth-eye structure.

Hereinafter, a surface treatment method for a substrate, a method for manufacturing a mold, and a mold according to an embodiment of the present invention will be described with reference to the drawings.

First, referring to FIG. 22, the relationship between the macro uneven structure constituting the conventional anti-glare structure and the dot pitch Px in the row direction will be described. FIGS. 22A and 22B are diagrams schematically showing the relationship between the macro uneven structure constituting the conventional anti-glare structure and the dot pitch Px in the row direction. Shows a case where the macro uneven structure is larger than the dot pitch Px, and FIG. 22B shows a case where the macro uneven structure is smaller than the dot pitch Px. Here, the dots refer to R, G, and B dots that constitute pixels in a typical color liquid crystal display panel. That is, when the pixel in the color liquid crystal display panel is composed of three dots (R dot, G dot, and B dot) arranged in the row direction, the pixel pitch in the row direction is the dot pitch Px in the row direction. Tripled. Note that the pixel pitch in the column direction is equal to the dot pitch Py in the column direction.

As schematically shown in FIGS. 22A and 22B, the surface 28s having a macro uneven structure constituting the conventional anti-glare structure has a continuous corrugated surface shape having no flat portion. The macro uneven structure having such a continuous corrugated surface shape is characterized by the average value of the distance between adjacent macro concave portions (average inter-adjacent distance AD _int ) or the two-dimensional size AD _p of the concave portions. . Here, attention is focused on macro concave portions, but the same can be characterized by focusing on convex portions.

As shown in FIG. 22A, the average distance AD _int between the recesses (considered to be equal to the two-dimensional size AD _{p of the} recesses) is, for example, the dot pitch Px in the row direction (pixels having three dots ( In the case of R, G, B), if the pixel pitch in the row direction is larger than 3 times the dot pitch), a sufficient anti-glare function cannot be obtained. In order to fully exhibit the antiglare function, as shown in FIG. 22B, the average adjacent distance AD _int (two-dimensional size AD _{p of the} recess) is substantially equal to each other and the dot pitch Is preferably smaller. The two-dimensional size of the recess means a two-dimensional expansion when viewed from the normal direction of the surface, and the recess is typically conical and when viewed from the normal direction of the surface. The shape of is substantially circular. At this time, the two-dimensional size corresponds to the diameter of the circle. If the convex portions are formed with a sufficiently high density, the average distance AD _int between two adjacent concave portions is substantially equal to the two-dimensional size AD _p of the concave portions. The pixel pitch is 254 μm for a display with a relatively low resolution, for example, a 100 ppi display. In the case of the antireflection film used in this display, the average distance AD _int between adjacent surfaces is preferably about 85 μm (254/3) or less.

For example, Patent Document 4 discloses a method for manufacturing an antireflection film in which a moth-eye structure is superimposed on an antiglare structure having a continuous corrugated surface 28s without a flat portion. With reference to FIG. 23, the manufacturing method of the moth-eye type | mold for forming the anti-reflective film which has the anti-glare function described in patent document 4 is demonstrated.

FIG. 23A is a cross-sectional view schematically showing an inverted antiglare structure for forming the antiglare structure, and FIG. 23B shows an inverted moth-eye structure superimposed on the inverted antiglare structure. FIG. 23C is a schematic cross-sectional view enlarging the inverted moth-eye structure.

The surface 18cs having an inverted antiglare structure for forming the antiglare structure having the continuous corrugated surface 28s having no flat portion shown in FIG. 23A is an outer peripheral surface of a cylindrical metal substrate. It is obtained by forming an insulating layer with an electrodeposition resin containing a matting agent and forming an aluminum film 18c on the insulating layer. That is, the surface of the insulating layer formed of an electrodeposition resin containing a matting agent has a continuous corrugated surface shape without a flat portion, and the surface 18cs of the aluminum film 18c formed on the insulating layer is: Reflecting the shape of the surface of the insulating layer, it has a continuous corrugated surface shape without a flat portion. Since the shape of the surface 18cs of the aluminum film 18c constitutes an inverted antiglare structure, the macro unevenness of the surface 18cs of the aluminum film 18c is opposite to the macro unevenness of the surface 28s constituting the antiglare structure. is there.

Next, as shown in FIG. 23 (b), anodization and etching are alternately repeated on the surface of the aluminum film 18c having an inverted antiglare structure, so that an anodized porous film having micro concave portions 14p is obtained. An alumina layer 14c is formed. In this way, the moth-eye mold 200 having a surface in which the inverted moth-eye structure is superimposed on the inverted anti-glare structure is obtained.

As schematically shown in FIG. 23C, the porous alumina layer 14c is densely filled with micro concave portions 14p. The micro concave portion 14p is generally conical and may have stepped side surfaces. The two-dimensional size (opening diameter: D _p ) of the micro concave portion 14p is preferably 10 nm or more and less than 500 nm, and the depth (D _depth ) is preferably about 10 nm or more and less than 1000 nm (1 μm). Moreover, it is preferable that the bottom part of the micro recessed part 14p is pointed (the bottom part is a point). Furthermore, it is preferable that the micro concave portions 14p are closely packed, and assuming that the shape of the micro concave portions 14p when viewed from the normal direction of the porous alumina layer 14c is a circle, adjacent circles overlap each other, It is preferable that a flange is formed between the adjacent micro concave portions 14p. When the substantially conical micro concave portions 14p are adjacent so as to form a collar portion, the two-dimensional size D _p of the micro concave portions 14p is assumed to be equal to the average inter-adjacent distance D _int . Therefore, the moth-eye type porous alumina layer 14c for producing the antireflection film has a dense micro concave portion 14p with D _p = D _int of 10 nm or more and less than 500 nm and D _depth of 10 nm or more and less than 1000 nm (1 μm). It is preferable to have an irregularly arranged structure. The arrangement of the micro concave portions does not need to be completely random, and may be irregular so that light interference and diffraction do not substantially occur. Since the shape of the opening of the micro concave portion 14p is not strictly a circle, D _p is preferably obtained from the SEM image of the surface. The thickness t _p of the porous alumina layer 14c is about 1 μm or less. The above description of the inverted moth-eye structure of the porous alumina layer 14c is also valid for the moth-eye mold according to the embodiment of the present invention.

The antireflection film formed using the mold manufactured by the mold manufacturing method described in Patent Document 4 has a problem that the image is blurred. This is because the inverted antiglare structure of the mold manufactured by the method described in Patent Document 4 has relatively large AD _int and AD _p . Therefore, in the manufacturing method described in Patent Document 4, it is difficult to form an antiglare structure that is suitably used for a high-definition display exceeding 300 ppi, for example.

According to embodiments of the present invention described below, an antiglare structure having an appropriate antiglare function (for example, a haze value of about 10 or more and about 50 or less) and an appropriate specular reflectivity, and an excellent antireflection effect are exhibited. An antireflective film (or antireflective surface) having a moth-eye structure is provided. In addition, according to the embodiment of the present invention, a mold for forming such an antireflection film is provided, and further, a method for efficiently manufacturing such a mold is provided. The mold manufactured by the mold manufacturing method according to the embodiment of the present invention is not limited to the illustrated example, and an antireflection film having a diffuse reflection performance with a small haze value (for example, about 2 or more and about 10 or less) is formed. Can also be used.

First, a mold manufacturing method according to an embodiment of the present invention and a mold structure manufactured by such a manufacturing method will be described with reference to FIGS.

FIGS. 1A to 1D are schematic cross-sectional views for explaining a method for manufacturing a moth-eye mold 100 according to an embodiment of the present invention.

The manufacturing method of the moth-eye mold 100 according to the embodiment of the present invention includes the following steps (i) to (vi).
Step (i): A step of preparing a cylindrical aluminum base material made of an Al—Mg—Si-based aluminum alloy and subjected to mechanical mirror finishing.
Step (ii): A step of treating the surface of the aluminum substrate with an aqueous solution containing a salt of hydrogen fluoride and ammonium (sometimes referred to as a satin treatment step).
Step (iii): A step of forming a mold base material by forming an inorganic material layer on the surface of the aluminum base material and forming an aluminum film on the inorganic material layer after the step (ii).
Step (iv): A step of forming a porous alumina layer having a plurality of micro concave portions by anodizing the surface of the aluminum film after the step (iii).
Step (v): A step of enlarging a plurality of micro concave portions of the porous alumina layer by bringing the porous alumina layer into contact with an etching solution after the step (iv).
Step (vi): A step of growing a plurality of microscopic recesses by further anodizing after step (v).

In this specification, the mold base means an object to be anodized and etched in the mold manufacturing process. The aluminum substrate means bulk aluminum that can be self-supported.

Referring to FIGS. 1 (a) to (d). FIG. 1A is a schematic cross-sectional view of the aluminum base 12 of the moth-eye mold 100, and FIG. 1B schematically shows the surface structure of the aluminum base 12 having an inverted antiglare structure. FIG. 1C is a schematic cross-sectional view of the mold base 10 in which the inorganic material layer 16 and the aluminum film 18 are formed on the surface of the aluminum base 12, and FIG. FIG. 3 is a schematic cross-sectional view of a moth-eye mold 100 having an inverted antiglare structure and an inverted motheye structure superimposed on the inverted antiglare structure.

FIG. 1 shows an enlarged part of the moth-eye mold 100, but the moth-eye mold 100 according to the embodiment of the present invention is cylindrical (roll-shaped). As disclosed in International Publication No. 2011/105206 by the present applicant, when a cylindrical moth-eye mold is used, an antireflection film can be efficiently produced by a roll-to-roll method. For reference purposes, the entire disclosure of WO 2011/105206 is incorporated herein by reference.

[Aluminum substrate]
First, as shown in FIG. 1 (a), a cylindrical aluminum substrate 12 formed of an Al—Mg—Si based aluminum alloy, which has been subjected to mechanical mirror finishing, prepare.

Byte cutting is preferred as the mechanical mirror finish. If, for example, abrasive grains remain on the surface of the aluminum base 12, electrical conduction between the aluminum film 18 and the aluminum base 12 is facilitated in a portion where the abrasive grains exist. In addition to the abrasive grains, where there are irregularities, local conduction between the aluminum film 18 and the aluminum substrate 12 is likely to occur. When local conduction is made between the aluminum film 18 and the aluminum base 12, there is a possibility that a battery reaction occurs locally between the impurities in the aluminum base 12 and the aluminum film 18.

As the aluminum substrate 12, an aluminum substrate 12 formed of an Al—Mg—Si based aluminum alloy (for example, JIS A6063) is used.

The cylindrical aluminum substrate 12 is typically formed by a hot extrusion method. The hot extrusion method includes a mandrel method and a porthole method, and it is preferable to use an aluminum substrate 12 formed by the mandrel method. A seam (weld line) is formed on the outer peripheral surface of the cylindrical aluminum substrate 12 formed by the porthole method, and the seam is reflected in the moth-eye mold 100. Therefore, depending on the accuracy required for the moth-eye mold 100, it is preferable to use the aluminum substrate 12 formed by the mandrel method.

In addition, the problem of a seam can be eliminated by performing cold drawing processing on the aluminum base material 12 formed by the porthole method. Of course, cold drawing may be applied to the aluminum substrate 12 formed by the mandrel method.

[Pear finish process with aqueous solution containing salt of hydrogen fluoride and ammonium]
Next, the surface of the aluminum base 12 is treated with an aqueous solution containing a salt of hydrogen fluoride and ammonium, so that the surface is inverted to the surface 12s of the aluminum base 12 as shown in FIG. An anti-glare structure is formed. The inverted anti-glare structure formed by the satin treatment has a plurality of macro convex portions 12p and a plurality of macro concave portions 12g. The macro convex portion 12p is substantially surrounded by the macro concave portion 12g, and the macro concave portion 12g exists as a groove that defines the outer periphery of the macro convex portion 12p.

An aqueous solution containing a salt of hydrogen fluoride and ammonium causes pitting corrosion. An aqueous solution containing a salt of hydrogen fluoride and ammonium has an advantage that it has less adverse effects on the human body and the environment than an aqueous solution of hydrogen fluoride. Examples of the salt of hydrogen fluoride and ammonium include ammonium fluoride (normal salt or neutral salt) and ammonium hydrogen fluoride (hydrogen salt or acidic salt). Since the aqueous solution containing ammonium fluoride has a weaker etching ability of aluminum than the aqueous solution containing ammonium hydrogen fluoride, there is an advantage that the margin of the matte treatment time can be increased. Ammonium fluoride has an advantage that it is superior to ammonium hydrogen fluoride in safety.

When ammonium fluoride is used as the salt of hydrogen fluoride and ammonium, the concentration of ammonium fluoride is, for example, 4 mass% to 8 mass%. In addition to ammonium fluoride, ammonium sulfate and / or ammonium dihydrogen phosphate may be added. Here, including the following experimental examples, an ammonium fluoride-added ammonium sulfate and ammonium dihydrogen phosphate were used as an etching solution for the finish treatment of aluminum. For example, ammonium fluoride (concentration: 4 mass% to 8 mass%) added with ammonium sulfate (concentration: 1 mass% to 3 mass%) and ammonium dihydrogen phosphate (concentration: 1 mass% to 3 mass%) can be used. . For example, the concentration of ammonium fluoride is preferably 5 mass%, the concentration of ammonium sulfate is 2 mass%, and the concentration of ammonium dihydrogen phosphate is preferably 2 mass%.

Even when an aqueous solution containing ammonium hydrogen fluoride as a salt of hydrogen fluoride and ammonium is used, an aqueous solution containing ammonium fluoride is used by appropriately adjusting the concentration, treatment temperature, and time. It is considered that an equivalent effect can be obtained. An aqueous solution containing ammonium hydrogen fluoride has a stronger etching ability for aluminum than an aqueous solution containing ammonium fluoride. The aqueous solution containing ammonium hydrogen fluoride can be prepared using, for example, a chemi-cleaner manufactured by Nippon CB Chemical Co., Ltd. In the international publication No. 2015/159797, the present applicant discloses an experimental example in which a satin treatment is performed using ammonium hydrogen fluoride as a salt of hydrogen fluoride and ammonium. For reference, the entire disclosure of WO2015 / 1599797 is incorporated herein by reference.

[Alkali cleaning process]
A step of etching the surface of the aluminum substrate 12 using an alkaline etchant before the step (step (ii)) of treating the surface of the aluminum substrate with an aqueous solution containing a salt of hydrogen fluoride and ammonium. (Vii) (hereinafter, also referred to as “alkali cleaning step”) may be further performed. At least a part of the work-affected layer of the aluminum substrate 12 that may cause cutting marks can be removed by an alkali cleaning step using an alkaline etching solution.

According to the study of the present inventor, when the matte finish is applied to the aluminum base material 12 that has been mirror-finished by cutting, cutting traces may be formed on the surface of the aluminum base material 12. The cut marks formed on the surface of the aluminum substrate 12 were also reflected in the aluminum film 18 formed on the aluminum substrate 12. In the present specification, not only the surface of the aluminum base 12 but also the trace caused by the cutting formed on the aluminum film 18 formed on the aluminum base 12 is referred to as “cutting trace”.

Note that the above-described cutting trace is considered to be etching unevenness caused by a work-affected layer formed on the surface of the aluminum base 12 by mirror finishing by cutting with a bite. Therefore, the problem that the cutting traces are formed by the satin treatment is not limited to cutting by a bite, but is a common problem when using the aluminum base material 12 that has been subjected to mirror finishing accompanied by the formation of a work-affected layer, and alkali cleaning. It can be solved by performing the process. Among mirror finishes, mechanical polishing such as cutting and grinding (Mechanical Polishing: MP), and chemical mechanical polishing (CMP) that uses both chemical polishing and mechanical polishing, form a work-affected layer. Accompany. In this specification, “mechanical mirror finishing” includes MP and CMP.

The alkaline etching solution for the alkali cleaning step includes, for example, an inorganic base (inorganic alkali) or an organic base (organic alkali). Inorganic bases include, for example, potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide and the like. The organic base includes, for example, a compound having an amino group. Organic bases include, for example, 2-aminoethanol (ethanolamine), primary alkanolamine, dimethylbis (2-hydroxy) ethyl, and the like. The pH of the alkaline etching solution is, for example, more than 7 and 12 or less, and preferably 8 or more and 10 or less. The alkaline etching liquid is not limited to the above, and for example, a known alkaline cleaning liquid may be used. The pH of the alkaline etching solution may be adjusted by adding a small amount of an acidic additive (for example, a chemical abrasive or a corrosion inhibitor) to the alkaline cleaning solution to prepare an alkaline etching solution. The composition and pH of the alkaline etching solution will be described later by showing experimental examples. Since an alkaline etching liquid is used for the alkali cleaning process, it can also serve as a degreasing process for the aluminum substrate.

After the alkali washing step, before the matte treatment step with an aqueous solution containing a salt of hydrogen fluoride and ammonium, a water washing step is performed as necessary. Moreover, it is not restricted to this, It is preferable to wash with water as needed during the process of using a different process liquid.

Instead of the alkali cleaning step, an anodizing step and an etching step for pretreatment may be performed before the matte treatment step. By performing the anodic oxidation process and the etching process for the pretreatment, cutting traces can be reduced. That is, cutting traces can be reduced by once anodizing the surface of the aluminum base 12 and removing the formed anodized film by etching. In the anodizing step for pretreatment, an aqueous sulfuric acid solution is preferably used as the electrolytic solution, and in the etching step for pretreatment, an aqueous phosphoric acid solution is preferably used as the etching solution.

Both the alkali cleaning step and the pre-treatment anodizing step and etching step may be performed before the satin treatment step. For example, the alkali cleaning step may be performed before the anodizing step and the etching step for pretreatment.

[Inorganic material layer]
Next, as shown in FIG. 1C, an inorganic material layer 16 is formed on the surface of the aluminum substrate 12, and an aluminum film 18 is formed on the inorganic material layer 16, thereby producing the mold substrate 10. To do.

On the surface of the aluminum film 18, a structure reflecting an inverted antiglare structure formed by subjecting the surface of the aluminum substrate 12 to a matte finish is formed. Here, the structure formed in the aluminum film 18 is also called an inverted antiglare structure. The inverted antiglare structure formed on the surface of the aluminum film 18 has substantially the same structure as the inverted antiglare structure formed on the surface of the aluminum substrate 12. Therefore, the inverted anti-glare structure formed on the surface of the aluminum film 18 has a plurality of macro convex portions 18p and a plurality of macro concave portions 18g. The macro convex portion 18p is substantially surrounded by the macro concave portion 18g, and the macro concave portion 18g exists like a groove that defines the outer periphery of the macro convex portion 18p.

As a material of the inorganic material layer 16, for example, tantalum oxide (Ta ₂ O ₅ ) or silicon dioxide (SiO ₂ ) can be used. The inorganic material layer 16 can be formed by sputtering, for example. When a tantalum oxide layer is used as the inorganic material layer 16, the thickness of the tantalum oxide layer is, for example, 200 nm.

The thickness of the inorganic material layer 16 is preferably 100 nm or more and less than 500 nm. If the thickness of the inorganic material layer 16 is less than 100 nm, defects (mainly voids, that is, gaps between crystal grains) may occur in the aluminum film 18 in some cases. Further, when the thickness of the inorganic material layer 16 is 500 nm or more, the aluminum base 12 and the aluminum film 18 are easily insulated from each other depending on the surface state of the aluminum base 12. In order to anodize the aluminum film 18 by supplying current to the aluminum film 18 from the aluminum substrate 12 side, it is necessary that a current flow between the aluminum substrate 12 and the aluminum film 18. If a configuration is adopted in which current is supplied from the inner surface of the cylindrical aluminum substrate 12, it is not necessary to provide an electrode on the aluminum film 18, so that the aluminum film 18 can be anodized over the entire surface, and the current is increased as the anodization proceeds. Therefore, the aluminum film 18 can be uniformly anodized over the entire surface without causing a problem that it is difficult to be supplied.

Further, in order to form the thick inorganic material layer 16, it is generally necessary to lengthen the film formation time. When the film formation time is lengthened, the surface temperature of the aluminum base 12 is unnecessarily increased. As a result, the film quality of the aluminum film 18 is deteriorated, and defects (mainly voids) may occur. If the thickness of the inorganic material layer 16 is less than 500 nm, the occurrence of such a problem can be suppressed.

[Aluminum film]
The aluminum film 18 is, for example, a film formed of aluminum having a purity of 99.99 mass% or more (hereinafter, also referred to as “high-purity aluminum film”) as described in Patent Document 3. The aluminum film 18 is formed using, for example, a vacuum deposition method or a sputtering method. The thickness of the aluminum film 18 is preferably in the range of about 500 nm or more and about 1500 nm or less, for example, about 1 μm.

As the aluminum film 18, an aluminum alloy film described in International Publication No. 2013/0183576 may be used instead of the high-purity aluminum film. The aluminum alloy film described in International Publication No. 2013/0183576 contains aluminum, a metal element other than aluminum, and nitrogen. In this specification, “aluminum film” includes not only a high-purity aluminum film but also an aluminum alloy film described in International Publication No. 2013/0183576. For reference purposes, the entire disclosure of WO2013 / 0183576 is incorporated herein by reference.

When using the aluminum alloy film, a mirror surface with a reflectance of 80% or more can be obtained. The average grain size of the crystal grains constituting the aluminum alloy film as viewed from the normal direction of the aluminum alloy film is, for example, 100 nm or less, and the maximum surface roughness Rmax of the aluminum alloy film is 60 nm or less. The content rate of nitrogen contained in the aluminum alloy film is, for example, not less than 0.5 mass% and not more than 5.7 mass%. The absolute value of the difference between the standard electrode potential of a metal element other than aluminum contained in the aluminum alloy film and the standard electrode potential of aluminum is 0.64 V or less, and the content of the metal element in the aluminum alloy film is 1.0 mass. % Or more and 1.9 mass% or less is preferable. The metal element is, for example, Ti or Nd. However, the metal element is not limited to this, and other metal elements whose absolute value of the difference between the standard electrode potential of the metal element and the standard electrode potential of aluminum is 0.64 V or less (for example, Mn, Mg, Zr, V, and Pb). Furthermore, the metal element may be Mo, Nb, or Hf. The aluminum alloy film may contain two or more of these metal elements. The aluminum alloy film is formed by, for example, a DC magnetron sputtering method. The thickness of the aluminum alloy film is also preferably in the range of about 500 nm to about 1500 nm, for example, about 1 μm.

Here, the inverted anti-glare structure will be described in detail with reference to FIGS. FIG. 2A is a schematic plan view of the inverted antiglare structure, and FIG. 2B is a schematic perspective view of the inverted antiglare structure.

As shown in FIGS. 2A and 2B, the inverted anti-glare structure formed by the satin treatment has a plurality of macro convex portions 18p and a plurality of macro concave portions 18g. The macro convex portion 18p is substantially surrounded by the macro concave portion 18g, and the macro concave portion 18g exists like a groove that defines the outer periphery of the macro convex portion 18p.

When viewed from the normal direction of the surface, the plurality of macro convex portions 18p have a substantially polygonal outer shape, but regularity is not seen in the arrangement. The two-dimensional size (area circle equivalent diameter) when viewed from the normal direction of the surface of the macro convex portion 18p is about 200 nm or more and 30 μm or less. The upper surface of the macro convex portion 18p is substantially flat.

The width of the macro concave portion (groove) 18g that substantially surrounds the macro convex portion 18p is about one-tenth to one-fifth of the two-dimensional size of the macro convex portion 18p. . The average value of the distance between adjacent macro concave portions 18g (average inter-adjacent distance AD _int ) is approximately equal to the average value of the two-dimensional size when viewed from the normal direction of the surface of the macro convex portion 18p. Can think. Here, since the macro concave portion 18g is formed so as to substantially surround the macro convex portion 18p, the adjacent macro concave portion 18g defines the two-dimensional size of the macro convex portion 18p. The macro concave portions 18g adjacent in the cross section in the direction are meant. Therefore, the average distance AD _int between the adjacent portions is approximately equal to the sum of the average value of the two-dimensional size of the macro-shaped convex portion 18p and the average value of the width of the macro-shaped concave portion 18g. The depth AD _depth of the macro concave portion 18g is, for example, 20 nm or more and 500 nm or less, but may be 20 nm or more and less than 5 μm.

After forming the inverted anti-glare structure, anodic oxidation and etching are alternately repeated to form the inverted moth-eye structure, whereby the moth-eye mold 100 shown in FIG. 1D is obtained. That is, in the process of forming the inverted moth-eye structure, the surface of the aluminum film 18 is anodized to form a porous alumina layer 14 having a plurality of micro recesses 14p, and then the porous alumina layer 14 Including a step of expanding a plurality of micro concave portions 14p of the porous alumina layer 14 by contacting with an etching solution, and a step of growing a plurality of micro concave portions 14p by further anodizing thereafter. To do. The electrolytic solution used for anodization is, for example, an aqueous solution containing an acid selected from the group consisting of oxalic acid, tartaric acid, phosphoric acid, sulfuric acid, chromic acid, citric acid, and malic acid. As an etchant, an aqueous solution of an organic acid such as formic acid, acetic acid, or citric acid or an aqueous solution of sulfuric acid, a mixed aqueous solution of chromic phosphoric acid, or an aqueous solution of an alkali such as sodium hydroxide or potassium hydroxide can be used.

It is preferable that the series of steps of repeating anodization and etching end with the anodization step. By ending with the anodizing step (the subsequent etching step is not performed), the bottom of the micro concave portion 14p can be reduced. A method for forming such an inverted moth-eye structure is disclosed, for example, in WO 2006/059686 by the applicant. For reference, the entire disclosure of WO 2006/059686 is incorporated herein by reference.

For example, an anodic oxidation step (electrolytic solution: oxalic acid aqueous solution (concentration 0.3 mass%, liquid temperature 10 ° C.), applied voltage: 80 V, application time: 55 seconds) and etching step (etching solution: phosphoric acid aqueous solution (10 mass%, 30 ° C.) ) And etching time: 20 minutes) alternately, a plurality of times (for example, 5 times: anodization is 5 times and etching is 4 times), thereby providing a micro concave portion 14p as shown in FIG. The moth-eye mold 100 having the porous alumina layer 14 is obtained. As described with reference to FIG. 23C, the porous alumina layer 14 formed under the conditions exemplified here has D _p = D _int of 10 nm or more and less than 500 nm, and D _depth of 10 nm or more and 1000 nm (1 μm). It has a structure in which micro recesses 14p of less than about are densely and irregularly arranged. The micro concave portion 14p has a substantially conical shape and is adjacent to form a collar portion.

The inverted moth-eye structure composed of the micro recesses 14p is formed so as to be superimposed on the antiglare structure. Therefore, as schematically shown in FIG. 1 (d), the micro concave portion 14p formed in the macro convex portion 18p constituting the antiglare structure and the micro concave portion 14p formed in the macro concave portion 18g are provided. Exists. The micro concave portion 14p formed in the macro concave portion 18g is deeper than the micro concave portion 14p formed in the macro convex portion 18p.

A barrier layer is formed under the micro concave portion 14p. The porous alumina layer 14 includes a porous layer having the micro concave portion 14p and a barrier layer (under the aluminum film side) (on the aluminum film side). The bottom of the recess 14p). It is known that the interval between the adjacent micro concave portions 14p (center-to-center distance) corresponds to approximately twice the thickness of the barrier layer and is approximately proportional to the voltage during anodization. Under the porous alumina layer 14, an aluminum remaining layer 18 r that has not been anodized in the aluminum film 18 is present.

As described above, according to the method for manufacturing the moth-eye mold 100 according to the embodiment of the present invention, the moth-eye mold 100 capable of forming the antireflection film having the antiglare function can be manufactured. The antiglare function of the antireflection film formed using the moth-eye mold 100 will be described in detail later by showing experimental examples.

Subsequently, with reference to FIG. 3, a manufacturing method of the antireflection film using the moth-eye mold 100 will be described. FIG. 3 is a schematic cross-sectional view for explaining a method for producing an antireflection film by a roll-to-roll method.

First, a cylindrical moth-eye mold 100 is prepared. The cylindrical moth-eye mold 100 is manufactured by the above-described manufacturing method.

As shown in FIG. 3, ultraviolet light (UV) is applied to the ultraviolet curable resin 32 ′ by irradiating the ultraviolet curable resin 32 ′ with the workpiece 42 having the ultraviolet curable resin 32 ′ pressed against the moth-eye mold 100. The cured resin 32 ′ is cured. As the ultraviolet curable resin 32 ′, for example, an acrylic resin can be used. The workpiece 42 is, for example, a TAC (triacetyl cellulose) film. The workpiece 42 is unwound from an unillustrated unwinding roller, and thereafter, an ultraviolet curable resin 32 ′ is applied to the surface by, for example, a slit coater. The workpiece 42 is supported by

support rollers

46 and 48 as shown in FIG. The

support rollers

46 and 48 have a rotation mechanism and convey the workpiece 42. The cylindrical moth-eye mold 100 is rotated in the direction indicated by the arrow in FIG. 3 at a rotational speed corresponding to the transport speed of the workpiece 42.

Thereafter, by separating the moth-eye mold 100 from the workpiece 42, a cured product layer 32 to which the uneven structure (inverted moth-eye structure) of the moth-eye mold 100 is transferred is formed on the surface of the workpiece 42. . The workpiece 42 having the cured product layer 32 formed on the surface is wound up by a winding roller (not shown).

4A to 4C, the structure of the antireflection film 32 having an antiglare function according to the embodiment of the present invention will be described. 4A to 4C are schematic views of the antireflection film 32 having an antiglare function according to the embodiment of the present invention. FIG. 4A is a view when the surface of the antireflection film 32 is observed from the vertical direction. 4B is a schematic diagram when the surface of the antireflection film 32 is observed from an oblique direction, and FIG. 4C is a schematic diagram of a cross section of the antireflection film 32.

4A to 4C, the plurality of micro convex portions constituting the moth-eye structure includes micro

convex portions

32p and 32g. The micro convex portion 32p is formed in a macro concave portion constituting the anti-glare structure, and the micro convex portion 32g is formed in a macro convex portion constituting the anti-glare structure. Therefore, the micro convex part 32g is higher than the micro convex part 32p, and is disposed so as to substantially surround the micro convex part 32p formed in the macro concave part. This corresponds to the fact that in the process of manufacturing the moth-eye mold 100, in the inverted anti-glare structure formed by the satin treatment, the macro convex portion 18p is substantially surrounded by the macro concave portion 18g. .

[Substrate surface treatment method]
According to the study of the present inventor, in the process of manufacturing the cylindrical moth-eye mold 100, the inverted anti-glare structure formed by the satin treatment is not uniformly formed on the surface of the aluminum base 12, so that the aluminum base Macro unevenness sometimes occurred on the 12 surfaces. According to the study by the present inventor, there are cases where there are a plurality of causes of macro unevenness. This problem is a common problem in the technique of treating the surface of a columnar or cylindrical substrate. This inventor examined the surface treatment method of the base material which can suppress generation | occurrence | production of macro unevenness.

Referring to FIGS. 5A and 5B, a surface treatment method for a substrate according to an embodiment of the present invention will be described. FIGS. 5A and 5B are schematic views for explaining a surface treatment method for a substrate according to an embodiment of the present invention.

The surface treatment method for a substrate according to an embodiment of the present invention is a method for treating the surface of a columnar or cylindrical substrate, and includes the following steps (I) and (II).
Step (I): A step of rotating the base material around the long axis of the base material in a state where the base material is arranged so that the long axis direction of the base material is substantially parallel to the horizontal direction.
Step (II): A step of bringing a part of the outer peripheral surface of the substrate into contact with the first etching solution accommodated in the first etching tank.

Here, the step of treating the surface of the aluminum base material with an aqueous solution containing a salt of hydrogen fluoride and ammonium (pear surface treatment step), included in the mold manufacturing method according to the embodiment of the present invention, An example using the surface treatment method will be described. However, the substrate surface treatment method according to the embodiment of the present invention is not limited to this. For example, the surface of the aluminum film may be anodized to form a porous alumina layer having a plurality of micro-recesses, or the porous alumina layer may be contacted with an etching solution to contact the porous alumina layer. You may use for the process of expanding several micro recessed part of these. Furthermore, the present invention is not limited to the mold manufacturing method according to the embodiment of the present invention, and can be widely used as a method for treating the surface of a columnar or cylindrical substrate. The surface treatment of the substrate includes various chemical treatment steps such as an etching step, a cleaning step, a film forming step, and a plating step. It may be a method of treating the surface (side surface) of a cylindrical substrate or the surface (outer peripheral surface) of a cylindrical substrate, or the surface (side surface) of a cylindrical substrate or a cylindrical substrate. A method of treating a metal film or an oxide film provided on the surface (outer peripheral surface) may also be used. The surface of the substrate may be a metal or an oxide.

As shown in FIG. 5A, a cylindrical aluminum base 12 and a first etching tank 51 are prepared. A first etching solution E <b> 1 is accommodated in the first etching tank 51. The first etching solution E1 is, for example, an etching solution for satin treatment, and is, for example, an aqueous solution containing a salt of hydrogen fluoride and ammonium. The length of the aluminum base 12 in the major axis direction is H, and the diameter of the outer peripheral surface in the cross section orthogonal to the major axis direction is D. As shown in FIG. 5B, a part of the outer peripheral surface of the aluminum base 12 is brought into contact with the first etching solution E1 accommodated in the first etching tank 51, so that the outer peripheral surface of the aluminum base 12 is satin-finished. Apply processing. Further, the aluminum base 12 is rotated around the long axis of the aluminum base 12 in a state where the long base of the aluminum base 12 is arranged in parallel with the horizontal direction. While rotating the aluminum substrate 12, a part of the outer peripheral surface of the aluminum substrate 12 may be brought into contact with the first etching solution E <b> 1 accommodated in the first etching tank 51. That is, the above step (I) and step (II) may be performed simultaneously.

The substrate surface treatment method according to the embodiment of the present invention can uniformly treat the surface of the substrate by rotating the aluminum substrate 12. In the substrate surface treatment method according to the embodiment of the present invention, the aluminum substrate 12 is rotated so that the entire aluminum substrate 12 is not immersed in the first etching solution contained in the first etching tank 51. The satin finish can be applied uniformly to the outer peripheral surface of the aluminum base 12. Therefore, it is possible to suppress the cost for the etching solution and the increase in the installation location of the etching tank. Moreover, since a part of outer peripheral surface of an aluminum base material is made to contact the 1st etching liquid E1 accommodated in the 1st etching tank 51, the 1st etching liquid accommodated in the 1st etching tank 51 is made to contact the 1st etching liquid. It is easier to circulate the first etching solution E1 in the first etching tank 51 than in the case where the whole is immersed.

In the above step (I), the peripheral speed of the aluminum base 12 is, for example, more than 0 m / s and 0.03 m / s or less. The rotation speed of the aluminum substrate 12 is, for example, more than 0 rpm and 2 rpm or less. When the rotation speed of the aluminum substrate 12 exceeds 2 rpm, the surface treatment of the substrate may not be performed uniformly. Here, since rpm is a unit representing the number of rotations per minute, a rotation speed of 1 rpm corresponds to a peripheral speed (π × D) / 60 (m / s). (In the present specification, “x” represents multiplication.) For example, when the aluminum base material 12 having a cross-sectional diameter D perpendicular to the major axis direction of 0.3 m rotates at a rotational speed of 2 rpm, the peripheral speed is It is 2 * pi * D / 60 = 0.03 (m / s). In the said process (I), it is preferable that the peripheral speed of the aluminum base material 12 is constant.

With reference to FIG. 6, the surface treatment method of the base material by a comparative example is demonstrated. In the substrate surface treatment method according to the comparative example, as shown in FIG. 6A, the major axis direction of the aluminum substrate 12 is arranged so as to be substantially parallel to the vertical direction and accommodated in the etching tank 91. The outer peripheral surface of the aluminum base 12 is brought into contact with the etched etchant. At this time, the entire aluminum base 12 is immersed in the etching solution in the etching tank 91. Therefore, the cost for the etching solution and the installation location of the etching tank 91 increase. For example, the depth of the etching tank 91 is larger than the length H of the aluminum base 12 in the major axis direction. Further, for example, considering that the aluminum base 12 is suspended from above and taken in and out of the etching tank 91, the height of the ceiling where the etching tank 91 is installed is the length of the aluminum base 12 in the major axis direction. Must be greater than twice H.

[Unevenness in the circumferential direction of the base material]
In the antireflection film 32 manufactured using the moth-eye mold 100 manufactured by the mold manufacturing method according to the embodiment of the present invention, periodic unevenness may occur.

This will be described with reference to FIG. FIG. 7 is a schematic diagram for explaining the cause of periodic unevenness. FIG. 7A shows the antireflection film 32 manufactured using the moth-eye mold 100 manufactured by the mold manufacturing method according to the embodiment of the present invention when observed from the normal direction of the antireflection film 32. It is a typical top view. FIG. 7 (b) is a schematic diagram for explaining a step of performing a matte treatment on the surface of the aluminum base 12 in the process of manufacturing the moth-eye mold 100, and the long axis of the cylindrical aluminum base 12. It is the schematic diagram seen from the direction.

As shown in FIG. 7A, the antiglare structure formed in the antireflection film 32 is periodically along the circumferential direction of the cylindrical aluminum substrate 12 (that is, the circumferential direction of the moth-eye mold 100). Has changed. This periodic unevenness is caused by the unevenness of the inverted anti-glare structure formed on the surface of the moth-eye mold 100, and the moth-eye mold in the method described with reference to FIG. 3 (that is, in a roll-to-roll manner). This is because the antireflection film 32 is formed using 100. When a part of the outer peripheral surface of the aluminum base 12 is brought into contact with the first etching solution E1, the contact time and timing are not uniform depending on the position on the outer peripheral surface of the aluminum base 12, so that the satin treatment is performed uniformly. However, the inverted antiglare structure has unevenness. The antiglare structure formed in the antireflection film 32 has periodic unevenness having a period of the circumference π × D of the bottom surface of the aluminum base 12 and is visually recognized as a difference in the degree of scattering of visible light. In FIG. 7A, the antireflection film 32 is divided into periods π × D to make the period easy to see, but the antireflection film 32 is not divided into periods π × D. .

In particular, as shown in FIG. 5 (b), when a part of the outer peripheral surface of the aluminum base 12 is brought into contact with the first etching liquid E1, the position where the first etching liquid E1 is first contacted is the aluminum base. 12 is on a line L1 extending in the major axis direction of the aluminum base 12 within the outer peripheral surface of the aluminum. On the line L1, since the first etching solution E1 is first contacted within the outer peripheral surface of the aluminum base 12, the matte treatment with the first etching solution E1 proceeds most quickly. That is, since the time of contact with the first etching solution E1 is the longest, the progress of the satin treatment is the largest. In addition, when the line L1 is first in contact with the first etching solution E1 within the outer peripheral surface of the aluminum base 12, the first etching solution E1 and the surface of the aluminum base 12 have less impurities. There is a tendency that the progress speed of the satin processing is the highest on the line L1. Corresponding to the line L1 of the aluminum base material, as shown by the broken line in FIG. On the outer peripheral surface of the aluminum base material 12, linear unevenness extending in the major axis direction of the aluminum base material 12 can be confirmed also in the optical image of FIG.

In order to suppress the occurrence of periodic unevenness, the present inventor has conceived a method of performing surface treatment with an etching solution having a low etching rate before and after the satin treatment step. This will be described with reference to FIGS. 8 and 9 are schematic views for explaining a surface treatment method for a substrate according to an embodiment of the present invention.

In one embodiment, the surface treatment method for a substrate according to an embodiment of the present invention includes the step (II) (a step of bringing a part of the outer peripheral surface of the substrate into contact with a first etching solution accommodated in a first etching tank. ), A step (II-1) of bringing a part of the outer peripheral surface of the base material into contact with a second etching solution different from the first etching solution (sometimes referred to as “pretreatment etching solution”) is further performed. Include. The etching rate of the second etching liquid with respect to the outer peripheral surface of the base material is lower than the etching rate of the first etching liquid with respect to the outer peripheral surface of the base material.

In one embodiment, the surface treatment method for a substrate according to an embodiment of the present invention includes the step (II) (a step of bringing a part of the outer peripheral surface of the substrate into contact with a first etching solution accommodated in a first etching tank. ), A step (II-2) of bringing a part of the outer peripheral surface of the base material into contact with a third etching solution different from the first etching solution (sometimes referred to as “post-treatment etching solution”) is further included. To do. The etching rate of the third etching liquid with respect to the outer peripheral surface of the base material is lower than the etching rate of the first etching liquid with respect to the outer peripheral surface of the base material.

As shown in FIG. 8A, before the step of bringing a part of the outer peripheral surface of the aluminum base 12 into contact with the first etching solution E1 accommodated in the first etching tank 51, the outer peripheral surface of the aluminum base 12 A step of bringing a part of the substrate into contact with the pretreatment etching solution E2 accommodated in the etching tank 52 is performed. After the step of bringing a part of the outer peripheral surface of the aluminum base 12 into contact with the first etching solution E1 accommodated in the first etching tank 51, a part of the outer peripheral surface of the aluminum base 12 was accommodated in the etching tank 52. You may perform the process made to contact the etching liquid E2 for post-processing. The pretreatment etchant and / or the posttreatment etchant can be obtained, for example, by diluting the first etchant. That is, the concentration of the pretreatment etchant and / or the posttreatment etchant is lower than that of the first etchant, for example. The pretreatment etchant and the posttreatment etchant are, for example, the same etchant, but may be different etchants.

Referring to FIG. 9, it will be described that the occurrence of periodic unevenness is suppressed by performing the surface treatment with the pretreatment etchant. When the surface treatment is not performed with the pretreatment etchant E2, the first etchant E1 directly acts on the outer peripheral surface of the aluminum base 12 as shown in FIG. On the other hand, when the surface treatment is performed in advance with the pretreatment etchant E2 having a low etching rate, the pretreatment etchant E2 is applied to the outer peripheral surface of the aluminum base 12 as shown in FIG. Act directly. It is preferable to adjust the concentration and temperature of the pretreatment etching solution E2 as appropriate so that the inverted antiglare structure is hardly formed by the pretreatment etching solution E2. For example, the pretreatment etchant and / or the posttreatment etchant can be obtained, for example, by diluting the first etchant five times. An experimental example will be given later for an etchant suitable for the pretreatment etchant E2. Thereafter, when the matte treatment process using the first etching solution E1 is performed, the first etching solution E1 passes through the pretreatment etching solution E2 attached to the outer peripheral surface of the aluminum base 12 as shown in FIG. 9B. Acting on the outer peripheral surface of the aluminum base 12. Thus, when a part of the outer peripheral surface of the aluminum base 12 is brought into contact with the first etching solution E1, the reaction rate of the satin treatment with the first etching solution E1 is first at the position where the first etching solution E1 comes into contact. In particular, the phenomenon of increasing is alleviated. In FIGS. 9A and 9B and FIG. 10A to be described later, the etching solution adhering to the outer peripheral surface of the aluminum base 12 is schematically shown for easy understanding. However, it may be omitted in other drawings.

Further, when the surface treatment with the post-treatment etching solution E2 is not performed, a cleaning step with, for example, pure water is performed after the matte treatment step with the first etching solution E1. The first etching solution and the pure water have greatly different concentrations. That is, since the etching rates with respect to the outer peripheral surface of the aluminum base 12 are greatly different, they can be in direct contact with each other on the outer peripheral surface of the aluminum base 12 to cause unevenness of the inverted antiglare structure. On the other hand, when the surface treatment with the post-treatment etchant is performed after the matte treatment step with the first etchant E1, the difference in concentration between the first etchant E1 and the post-treatment etchant is small, so The occurrence of uneven antiglare structure is suppressed.

Step (II-1) (step of bringing a part of the outer peripheral surface of the substrate into contact with the pretreatment etching solution before the satin treatment step) and step (II-2) (after the satin treatment step, the substrate Also in the step of bringing a part of the outer peripheral surface of the aluminum substrate 12 into contact with the post-treatment etching solution, it is preferable to rotate the aluminum substrate 12 around the major axis of the aluminum substrate 12 as in the step (I). The rotation speed of the aluminum substrate 12 in the step (II-1) and the step (II-2) is substantially the same as the rotation speed in the step (I), for example.

There may be a plurality of surface treatment steps with the pretreatment etchant. As shown in FIG. 8 (a), the substrate surface treatment method according to the embodiment of the present invention is performed before the step of bringing a part of the outer peripheral surface of the aluminum substrate 12 into contact with the pretreatment etchant E2. You may further include the process of making a part of outer peripheral surface of the base material 12 contact the etching liquid E3 for pre-processing accommodated in the etching tank 53. FIG. The etching rate of the pretreatment etching liquid E3 with respect to the outer peripheral surface of the aluminum base 12 is lower than the etching rate of the pretreatment etching liquid E2 with respect to the outer peripheral surface of the aluminum base 12.

Similarly, there may be a plurality of processes for the surface treatment with the post-treatment etching solution. After the step of bringing a part of the outer peripheral surface of the aluminum base 12 into contact with the post-processing etchant E2, a part of the outer peripheral surface of the aluminum base 12 is brought into contact with the post-processing etchant E3 accommodated in the etching tank 53. You may further include the process to make. The etching rate of the post-processing etchant E3 with respect to the outer peripheral surface of the aluminum base 12 is lower than the etching rate of the post-processing etchant E2 with respect to the outer peripheral surface of the aluminum base 12.

As shown in FIG. 8B, the pretreatment etching solution and / or the posttreatment etching solution may be stored in the first etching tank 51 in which the first etching solution E1 is stored. In this case, typically, the pretreatment etchant and / or the posttreatment etchant is obtained by lowering the temperature of the first etchant E1.

As described above, the etching solution that contacts the outer peripheral surface of the aluminum base 12 has a gentle change in the etching rate with respect to the outer peripheral surface, so that the inverted antiglare structure formed in the aluminum base 12 in the circumferential direction. Unevenness can be suppressed. For example, unevenness in the circumferential direction of the inverted antiglare structure formed on the aluminum substrate 12 can be suppressed by gradual change in the concentration of the etching solution that contacts the outer peripheral surface of the aluminum substrate 12. .

Similarly, unevenness in the circumferential direction of the inverted antiglare structure formed on the aluminum base 12 can be suppressed by moderately changing the temperature of the outer peripheral surface of the aluminum base 12. For example, the processing temperature of the first etching solution and / or the pretreatment etching solution may be set low in order to increase the time margin for the matte processing. At this time, if the temperature of the outer peripheral surface of the aluminum base 12 to be processed is higher than the temperature of the etching solution, macro unevenness may occur in the inverted antiglare structure formed on the aluminum base 12. For this problem, the temperature of the outer peripheral surface of the aluminum base 12 is low (for example, approximately 10 ° C.) before the step of bringing a part of the outer peripheral surface of the aluminum base 12 into contact with the first etching solution or the pretreatment etching solution. Since the temperature of the outer peripheral surface of the aluminum base 12 can be lowered by providing the step of spraying pure water, unevenness generation can be suppressed. The step of spraying low-temperature pure water is performed by a shower method using a nozzle, for example.

In addition, in the surface treatment method of the base material of the comparative example described with reference to FIG. 6A, the problem that unevenness in the circumferential direction of the base material described above hardly occurs. As shown in FIG. 6A, when a moth-eye mold is manufactured using the surface treatment method for a base material of a comparative example, when the outer peripheral surface of the aluminum base material 12 is brought into contact with the first etching solution E1, first, The position in contact with the first etching solution E1 is the bottom surface of the aluminum base 12. When the antireflection film 32 is manufactured using the moth-eye mold, linear unevenness appears at the end of the antireflection film 32 (broken line in FIG. 6B), so that the portion is excluded and used as the antireflection film. Is easy. Further, no periodic unevenness appears in the antireflection film 32. In some cases, unevenness may occur in the direction corresponding to the major axis direction of the moth-eye mold (the major axis direction of the aluminum base material 12). If it can be immersed in all within 3 seconds, it can be suppressed. However, as described above, the substrate surface treatment method of the comparative example is inferior to the substrate surface treatment method according to the embodiment of the present invention in that the cost for the etching solution and the installation location of the etching tank increase. . In particular, when the length H and / or the diameter D in the major axis direction of the substrate is large, there is a problem in that the cost for the etching solution and the installation location of the etching tank increase in the surface treatment method of the substrate of the comparative example. Become prominent.

[Unevenness in the major axis direction of the substrate]
As shown in FIG. 10 (b), the aluminum base material 12 that has been subjected to the satin treatment by the surface treatment method of the base material according to the embodiment of the present invention has the aluminum base material 12 on the outer peripheral surface. A plurality of streaky irregularities extending in a direction substantially orthogonal to the major axis direction may occur. Streaky irregularities were also visually recognized in the antireflection film 32 produced using the moth-eye mold. The inventor of the present invention has come up with a method of spraying an etching solution for the satin treatment on the outer peripheral surface of the aluminum base 12 in order to suppress the occurrence of streaky unevenness.

This will be described with reference to FIGS. 10 (a) to 10 (d). FIG. 10A is a schematic diagram for explaining a substrate surface treatment method according to an embodiment of the present invention. FIG. 10 (b) is a schematic diagram for explaining a plurality of streaky irregularities that extend on the outer peripheral surface of the aluminum base 12 and extend in a direction substantially orthogonal to the major axis direction of the aluminum base 12. FIGS. 10C and 10D are schematic diagrams for explaining the angle θ at which the spray etching solution is ejected.

As shown to Fig.10 (a), the surface treatment method of the base material by embodiment of this invention WHEREIN: In one embodiment, it is the 4th etching liquid (it is called the etching liquid for spraying) which is the same as the 1st etching liquid E1. There is further included the step (III) of spraying E4 on the outer peripheral surface of the aluminum base 12.

In the step (III) of spraying the spraying etchant E4 on the outer peripheral surface of the aluminum substrate 12, for example, a part of the outer peripheral surface of the aluminum substrate 12 is brought into contact with the first etchant E1 accommodated in the first etching tank 51. The spraying etching solution E4 is sprayed in the vicinity of the portion in contact with the first etching solution E1 in the outer peripheral surface of the aluminum substrate 12. “The vicinity of the portion in contact with the first etching solution E1 in the outer peripheral surface of the aluminum base 12” includes the portion in contact with the first etching solution E1 in the outer peripheral surface of the aluminum base 12. .

An optical image of the aluminum substrate 12 is shown in FIGS. 11 (a) and 11 (b). Fig.11 (a) is the aluminum base material 12 by which the matte process was given by the surface treatment method which does not include the said process (III) (process which sprays the etching liquid for spraying on the outer peripheral surface of the aluminum base material 12), 11 (b) is the aluminum substrate 12 that has been subjected to a satin treatment by the surface treatment method including the above-described step (III) (step of spraying the spraying etching solution onto the outer peripheral surface of the aluminum substrate 12). It can be seen that streaky irregularities appear on the surface of the aluminum substrate 12 in FIG. 11A, but not on the aluminum substrate 12 in FIG.

The striped unevenness is considered to be caused by the uneven thickness of the etchant liquid film on the outer peripheral surface of the aluminum base 12. According to the study of the present inventor, the portion of the outer peripheral surface of the aluminum substrate 12 where the thickness of the etching solution liquid film is thin has a high density of the macroscopic projections 12p, and the etching solution liquid film is thick. It was confirmed that the density tends to be low in the density of the macro convex portions 12p. That is, it is considered that the reaction rate of the satin treatment is high at a portion where the thickness of the etchant liquid film is thin, and the reaction rate of the satin treatment is slow at a portion where the thickness of the etchant liquid film is thick. When the spraying etching solution E4 is sprayed in the vicinity of the portion of the outer peripheral surface of the aluminum substrate 12 that is in contact with the first etching solution E1, the thickness of the liquid film on the outer peripheral surface of the aluminum substrate 12 becomes uniform. By doing so, it is considered that the occurrence of streaky irregularities can be suppressed.

In the step (III) of spraying the spray etching solution E4 on the outer peripheral surface of the aluminum base material 12, for example, the base material is arranged so that the major axis direction of the base material is substantially parallel to the horizontal direction. It is performed simultaneously with the step of rotating the substrate around the major axis (the step (I) above), and the spray etching solution E4 contacts the first etching solution E1 in the outer peripheral surface of the aluminum substrate 12. It is sprayed to the location which is rotating so that it may be away from the 1st etching liquid E1 accommodated in the 1st etching tank 51 in the said process (I) vicinity.

The step (III) of spraying the spray etching solution E4 on the outer peripheral surface of the aluminum base 12 is performed using, for example, a spray nozzle. As the spray nozzle, for example, a fan-shaped one-fluid nozzle (for example, HB1 / 4VV-SS11004 manufactured by Spraying Systems) can be used. A plurality of spray nozzles may be arranged side by side along the long axis direction of the aluminum base 12. By using a plurality of spray nozzles, it is possible to uniformly spray the spraying etching solution E4 on the portion of the outer peripheral surface of the aluminum base 12 that is in contact with the first etching solution E1. For example, in the surface treatment of the aluminum base 12 having a length H in the major axis direction of 1.6 m, the spray etching solution E4 may be sprayed using 16 spray nozzles.

The flow rate of the spray etching solution E4 sprayed from each spray nozzle is, for example, 1.0 L / min, and preferably 0.6 L / min to 1.2 L / min. The pump can be appropriately selected from known pumps according to the flow rate and pressure of the spray etching solution E4. For example, CHI2-30AWGBUBV manufactured by Grundfos can be used.

In the step (III) of spraying the spraying etchant E4 onto the outer peripheral surface of the aluminum base 12, the angle θ at which the spraying etchant E4 is sprayed is, for example, 45 ° or more and less than 90 ° from the vertical direction. As shown in FIG. 10C, the inclination angle with respect to the horizontal direction, that is, the inclination angle with respect to the surface of the first etching solution E1 accommodated in the first etching tank 51 is 90 ° −θ. If the angle θ is less than 45 °, the inclination angle (90 ° −θ) with respect to the surface of the first etching liquid E1 accommodated in the first etching tank 51 is large, so that the spraying etching liquid E4 is in the first etching tank. In some cases, the surface of the first etching solution E1 accommodated in the substrate 51 may jump on the surface (liquid surface) of the first etching solution E1 and adhere to the surface of the aluminum base 12. As shown in FIG. 10 (d), when the angle θ is 90 ° or more, the spraying etching solution E 4 may splash and scatter on the surface of the aluminum base 12. When the angle θ is 90 ° or more, the effect of making the thickness of the liquid film on the outer peripheral surface of the aluminum base 12 uniform may not be obtained.

Hereinafter, with reference to experimental examples, the moth-eye mold and the moth-eye mold manufacturing method according to the embodiment of the present invention will be described in more detail.

[Composition of etching solution for satin treatment]
The satin treatment process was performed by changing the composition of the etching solution for the satin treatment.

As shown in Table 1 below, Experimental Example 1-1, Experimental Example 2-1, Experimental Example 3-1 and 4-1 are ammonium fluoride, ammonium sulfate and dihydrogen phosphate in an etching solution for satin treatment. While the ratio of ammonium was fixed at 5: 2: 2, these concentrations were changed, and a satin treatment process was performed on small pieces (5 cm × 2 cm) of the aluminum base material. As shown in Table 1, the etching solution for the satin treatment used in Experimental Example 1-1 contains 5 mass%, 2 mass%, and 2 mass% of ammonium fluoride, ammonium sulfate, and ammonium dihydrogen phosphate, respectively. The etching solution for the satin treatment used in Experimental Examples 2-1 to 4-1 is obtained by diluting the etching solution used in Experimental Example 1-1 by 2 times, 3 times, and 5 times, respectively. .

As the aluminum base material, an Al—Mg—Si based aluminum alloy formed from JIS A6063 was used. JIS A6063 has the following composition (mass%).
Si: 0.20 to 0.60%, Fe: 0.35% or less, Cu: 0.10% or less, Mn: 0.10% or less, Mg: 0.45 to 0.9%, Cr: 0. 10% or less, Zn: 0.10% or less, Ti: 0.10% or less, Other: Individual is 0.05% or less, the whole is 0.15% or less, the balance: Al

The aluminum substrate (JIS A6063) was formed by a hot extrusion method using indirect extrusion (mandrel method), subjected to cold drawing, and then subjected to mirror surface processing by cutting. An alkali cleaning process was performed on the aluminum substrate before the satin treatment process. As an alkaline etching solution, an aqueous solution containing an organic alkaline detergent (product name: Semi-clean LC-2, manufactured by Yokohama Oil & Fat Co., Ltd.) at a concentration of 8 mass% was used. Semi-clean LC-2 manufactured by Yokohama Oil & Fat Co., Ltd. has the following composition: 2-aminoethanol (12 mass%), chelating agent (2 mass% to 6 mass%), and surfactant (2 mass% to 6 mass%). The aluminum substrate was immersed in an alkaline etching solution at 40 ° C. for 30 minutes (alkali cleaning step). Then, the aluminum base material was immersed in pure water for washing with water, and after rinsing with water, the aluminum substrate was immersed in an etching solution (temperature: 10 ° C.) for a satin treatment process for a predetermined time (pear texture treatment process). Thereafter, the aluminum substrate was washed by immersing it in pure water and dried by air blow.

For Experimental Examples 1-1 to 4-1, an antiglare film was formed using each aluminum substrate as a mold. The anti-glare film is coated with a mold release agent (Optool DSX manufactured by Daikin Industries, Ltd.) on the surface of an aluminum substrate, then coated with a urethane acrylate UV curable resin, and irradiated with UV light in a state of being transferred onto a TAC film. And then cured. As in the sample film used here, a film that does not have a moth-eye structure and has only an antiglare structure is sometimes referred to as an antiglare film.

Table 1 shows the results of evaluating the antiglare function using the aluminum base material of Experimental Examples 1-1 to 4-1 and the antiglare film (sample film) obtained from the aluminum base material. FIGS. 12A to 12D show optical microscopes when the surface of an aluminum substrate having an inverted antiglare structure formed by the matte treatment process of Experimental Examples 1-1 to 4-1 is observed from the vertical direction. FIGS. 12E to 12H show SEM images when the surface of the antiglare film formed from the aluminum base material of Experimental Examples 1-1 to 4-1 is observed from the vertical direction. (Full scale 20 μm in SEM image). The optical microscope image was acquired using an optical microscope (manufactured by Olympus Corporation, product name: BH2-UCB (BX-16)). The same applies to the following optical microscope images. The SEM image was acquired using a field emission scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, product name: S-4700). The same applies to the following SEM images.

“Macro-convex portion 12p” in Table 1 indicates a two-dimensional size (area equivalent circle diameter) when viewed from the normal direction of the surface of the macro-protrusion portion 12p formed on the aluminum base 12. It is a value estimated from an optical microscope image.

“Haze value” in Table 1 indicates the result of measuring the haze value of the antiglare film. The haze value was obtained from (diffuse transmittance / total light transmittance) × 100 using a haze meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.

“Anti-glare property” in Table 1 indicates that an anti-glare film is formed on a liquid crystal television (AQUAS LC-UD1, type 60, manufactured by Sharp Corporation, dot pitch in the row direction: about 115 μm, dot pitch in the column direction: about 345 μm). It is the result of judging the presence or absence of anti-glare property by affixing on the surface of a display panel and observing the reflection of a fluorescent lamp visually. Regarding “Anti-Glare” in Table 1, “◯” indicates that it is determined that there is anti-glare, and “X” indicates that it is determined that there is no anti-glare. In general, an antiglare film having a large haze value is excellent in antiglare function and antiglare property.

“Glitter” in Table 1 indicates that the anti-glare film is a display of a liquid crystal television (AQUAS LC-UD1, type 60, manufactured by Sharp Corporation, dot pitch in the row direction: about 115 μm, dot pitch in the column direction: about 345 μm) This is a result of pasting on the surface of the panel, displaying the entire surface in green, and hearing whether the image through the film is glaring. Interviews were conducted with 5 people. For “Glitter” in Table 1, “○” indicates that 0 out of 5 people answered “Glitter is visible”, and “△” was 1 The above indicates that the number is 3 or less, and “x” indicates that the number is 4 or more.

The glare is a phenomenon in which the display panel appears to be glaring as a whole, and it tends to be noticeable especially when the entire screen is displayed in green. The glare is caused by the average distance between adjacent macro projections 12p (see AD _int in FIG. 1C), the row direction dot pitch Px (see FIG. 22) and / or the column direction dot pitch Py of the display panel. From this relationship, it is considered that the antiglare structure formed in the antiglare film and the dots of the display panel interfere with each other. The glare may also occur when the average distance between adjacent macro convex portions 12p is smaller than the dot pitch. The glare tends to be suppressed when the average distance between adjacent macro projections 12p and the two-dimensional size of the macro projection 12p are sufficiently smaller than the dot pitch.

As can be seen from Table 1 and FIG. 12, the size of the macro convex portion 12p formed on the aluminum base 12 varies depending on the concentration of the etching solution for the satin treatment. The antiglare film obtained in Experimental Example 1-1 has excellent antiglare properties and can suppress glare. In Experimental Example 2-1, which uses an etching solution obtained by diluting the etching solution of Experimental Example 1-1 twice, the two-dimensional size (about 15 μm) of the macro convex portion 12p is different from Experimental Example 1-1. In Experimental Example 3-1, which is larger than (about 10 μm) and uses an etching solution obtained by diluting the etching solution of Experimental Example 1-1 three times, the two-dimensional size of the macro-shaped protrusion 12p is even larger. (About 20 μm). The antiglare film of Experimental Example 2-1 was inferior to the antiglare film of Experimental Example 1-1 from the viewpoint of suppressing glare, and the antiglare film of Experimental Example 3-1 could not suppress glare. .

On the other hand, in Experimental Example 4-1, using an etching solution obtained by diluting the etching solution of Experimental Example 1-1 five times, the macro-projections 12p were not formed on the surface of the aluminum base 12 (FIG. 12). (D)). As a result, the antiglare film of Experimental Example 4-1 did not have antiglare properties. The black spots in the optical microscope image of FIG. 12D are galvanic corrosion generated by the alkali cleaning process. Galvanic corrosion that occurs in the alkali cleaning step will be described later.

The etching solution used in Experimental Example 4-1 does not form the macro-projections 12p on the surface of the aluminum substrate 12, and is therefore preferably used as a pretreatment etching solution and / or a posttreatment etching solution.

The experimental example 1-2, the experimental example 1-3, the experimental example 2-2, the experimental example 3-2, and the experimental example 4-2 shown in Table 2 are different from the experimental example in Table 1 in the matte treatment time. Other experimental conditions and evaluation procedures are the same as those described for Table 1.

Using the aluminum substrate of Experimental Example 1-2, Experimental Example 1-3, Experimental Example 2-2, Experimental Example 3-2, and Experimental Example 4-2 and the antiglare film (sample film) obtained from the aluminum substrate The results of evaluating the antiglare function are shown in Table 2. 13 (a) to (e) are inverted formed by the satin treatment process of Experimental Example 1-2, Experimental Example 1-3, Experimental Example 2-2, Experimental Example 3-2 and Experimental Example 4-2. The optical microscope image (50 times) when the surface of the aluminum base material which has an anti-glare structure is observed from the perpendicular direction is shown.

Comparing Table 1 and Table 2, it can be seen that the glare and antiglare evaluation results of the antiglare film did not change depending on the time of the satin treatment. It can be seen that the concentration of the etching solution for the satin treatment greatly contributes to the glare and antiglare property of the antiglare film. In addition, the etching solution used in Experimental Example 4-2 does not form the macro-convex portion 12p on the surface of the aluminum base 12 like the etching solution used in Experimental Example 4-1. It is suitably used as a solution and / or an etching solution for post-treatment.

Subsequently, as shown in Table 3, the experiment was performed by changing the ratio of ammonium fluoride, ammonium sulfate, and ammonium dihydrogen phosphate in the etching solution for the satin treatment from 5: 2: 2. In Experimental Examples 5-1 to 5-4, the ratio of any of ammonium fluoride, ammonium sulfate, and ammonium dihydrogen phosphate was changed from the composition of the etching solution for the satin treatment used in Experimental Example 1-1. Is. In Experimental Examples 6-1 and 6-2, the ratio of any one of ammonium fluoride, ammonium sulfate, and ammonium dihydrogen phosphate was changed from the composition of the etching solution for the satin treatment used in Experimental Example 2-1. Is. Experimental conditions and evaluation procedures are basically the same as those described for Table 1. However, the satin treatment time is different from that in Table 1.

Table 3 shows the results of evaluation of the antiglare function using the aluminum base materials of Experimental Examples 5-1 to 5-4 and Experimental Examples 6-1 to 6-2 and the antiglare films (sample films) obtained from the aluminum base materials. Shown in FIGS. 14A to 14D show optical microscopes when the surface of an aluminum substrate having an inverted antiglare structure formed by the satin treatment process of Experimental Examples 5-1 to 5-4 is observed from the vertical direction. FIGS. 14 (e) and 14 (f) show SEM images when the surface of the antiglare film formed from the aluminum base material in Experimental Examples 5-3 and 5-4 is observed from the vertical direction. (Full scale 20 μm in SEM image). FIGS. 15 (a) and 15 (b) show optical microscopes when the surface of an aluminum substrate having an inverted antiglare structure formed by the satin treatment process of Experimental Examples 6-1 and 6-2 is observed from the vertical direction. An image (50 times) is shown.

By comparing the results of Experimental Example 5-3 (Table 3 and FIG. 14) with the results of Experimental Example 1-1, when the ammonium fluoride content was reduced, the haze value of the antiglare film was reduced, and aluminum It can be seen that the two-dimensional size of the macro convex portion 12p formed on the substrate 12 tends to increase. This tendency is the same as that when the etching solution of Experimental Example 1-1 was diluted twice (Experimental Example 2-1). In Experimental Example 5-4, when the content of ammonium fluoride is further reduced, the macro-projection 12p is formed in the same manner as when the etching solution of Experimental Example 1-1 was diluted five times (Experimental Example 4-1). Not formed.

As in Experimental Example 5-2 and Experimental Example 6-1, it is possible to produce an antiglare film that has antiglare properties and can suppress glare even with an etching solution that does not contain ammonium dihydrogen phosphate. did it. Experimental example 5-2 has a longer satin processing time than experimental example 1-1 (pear finishing time: 2 minutes), and experimental example 6-1 has experimental example 2-1 (pear finishing time: 2). As compared with the case of (min), the matte treatment time is longer, and therefore an advantage that the margin of the matte treatment time can be increased by using an etching solution not containing ammonium dihydrogen phosphate. However, since ammonium dihydrogen phosphate has an effect of suppressing unevenness of the satin treatment, the etching solution preferably contains ammonium dihydrogen phosphate. In the etching solution not containing ammonium dihydrogen phosphate, bubbles may be generated in the satin treatment process. In order to suppress unevenness of the satin treatment due to the generation of bubbles, it may be preferable to add an antifoaming agent as appropriate.

As in Experimental Example 5-1 and Experimental Example 6-2, when an etching solution containing no ammonium sulfate is used, the two-dimensional size of the macro-shaped convex portion 12p is larger than when an etching solution containing ammonium sulfate is used. Tended to increase. That is, the two-dimensional size of the macro protrusion 12p formed on the aluminum base material of Experimental Example 5-1 is larger than that of Experimental Example 1-1, and is formed on the aluminum base material of Experimental Example 6-2. The two-dimensional size of the macro-convex portion 12p thus formed was larger than that of Experimental Example 2-1. The antiglare film of Experimental Example 5-1 is inferior to the antiglare film of Experimental Example 1-1 in terms of suppressing glare. The antiglare film of Experimental Example 6-2 could not suppress glare.

[Composition of alkaline etching solution for alkali cleaning process]
First, the effect of the alkali cleaning step using an alkaline etching solution was examined.

The conditions were changed as shown in Table 4 below, and the washing step was performed with an acidic washing solution, a neutral washing solution and an alkaline washing solution (sometimes called an alkaline etching solution) before the satin treatment step. As the acidic cleaning liquid, an aqueous solution containing an acidic cleaning agent (manufactured by Yokohama Oil & Fat Co., Ltd., product name: scale cut P) at a concentration of 3 mass% was used. Scale Cut P manufactured by Yokohama Oil & Fat Co., Ltd. contains 5 mass% to 15 mass% of citric acid as an acid. As a neutral cleaning solution, an aqueous solution containing a neutral cleaning agent (manufactured by Sanwa Oil Chemical Co., Ltd., product name: Sun Clean HS) at a concentration of 3 mass% is used. As an alkaline etching solution, an organic alkaline cleaning agent is used. An aqueous solution containing 8 mass% (product name: Semi-clean LC-2, manufactured by Yokohama Oil & Fat Co., Ltd.) was used.

As the etchant for the satin finish, the same etchant as the satin finish used in Experimental Example 1-1 was used. That is, 5 mass%, 2 mass%, and 2 mass% of ammonium fluoride, ammonium sulfate, and ammonium dihydrogen phosphate are included, respectively. The aluminum base pieces used are the same as described for Table 1.

It was confirmed that the surface of the aluminum substrate after washing with acidic, neutral and alkaline washing solutions had hydrophilicity. Specular reflectivity was confirmed on the surface of the aluminum substrate after washing with acidic and neutral washing solutions. On the surface of the aluminum substrate after washing with an alkaline washing liquid, diffuse reflection (including scattering) properties were confirmed together with specular reflection. In Table 4, “X” indicates that a cutting trace was formed, and “◯” indicates that a cutting trace was not formed. In Table 4, regarding “crystal grains”, “x” indicates that the crystal grains are conspicuous, and “◯” indicates that almost no crystal grains are confirmed. No cutting marks were formed on the surface of the aluminum base material that had been subjected to the matting treatment step after the washing step with an alkaline washing solution, and no crystal grains were confirmed. Cutting traces were formed on the surface of the aluminum base material subjected to the matte treatment step after the washing step with the acidic and neutral washing liquid. The surface of the aluminum base material that had been subjected to the matting treatment process after performing the washing process with a neutral washing solution was almost free of crystal grains, but after the washing step was performed with an acidic washing solution, the matte treatment process was performed. On the surface of the aluminum substrate, crystal grains were conspicuous. When crystal grains are conspicuous on the surface of an aluminum substrate, an anti-glare film is affixed to the surface of the display panel, and when viewed from an angle inclined from the normal direction of the anti-glare film, the image through the film appears to be whitish There is.

From the results shown in Table 4, it is preferable to use an alkaline etching solution for the cleaning step before the satin treatment step. By performing the alkali cleaning step with an alkaline etching solution before the matte treatment step, formation of cutting marks could be suppressed. When a neutral cleaning liquid was used, the formation of cutting marks could not be suppressed. It has been found that when an acidic cleaning liquid is used, the formation of cutting traces cannot be suppressed, and crystal grains (crystal grain boundaries) of the aluminum base material are conspicuous.

In the experimental examples in this specification, the alkaline etching solution and the etching solution for the satin treatment were all prepared on the day of performing the alkali cleaning step or the satin treatment step. According to the study of the present inventor, a remarkable difference sometimes appears in the inverted antiglare structure obtained between the etching solution prepared on that day and the etching solution prepared one week ago.

As shown in Table 4, the formation of cutting marks could be suppressed by performing an alkali cleaning step using an alkaline etching solution before the matte treatment step. It is considered that at least a part of the work-affected layer of the aluminum base material that could cause cutting marks could be removed by the alkaline etching solution. However, according to the study of the present inventor, the following problems may occur depending on the type of alkaline etching solution.

In general, it is considered that the thicker the work-affected layer removed from the surface of the aluminum base 12 is, the more the formation of cutting marks is suppressed. For example, the work-affected layer removed from the surface of the aluminum base 12 can be thickened by immersing the aluminum base 12 in an alkaline etching solution for a long time. However, since the oxide film on the surface of the aluminum substrate 12 is removed by the alkaline etching solution, galvanic corrosion proceeds on the surface from which the oxide film has been removed, and as a result, a large number of recesses (pitting corrosion) are formed. The Galvanic corrosion occurs between Ti and Al contained in the aluminum substrate 12.

First, in order to investigate the formation of a recess due to galvanic corrosion, only an alkali cleaning process was performed on the aluminum base material under the conditions shown in Table 5. As the alkaline etching solution, an aqueous solution containing an organic alkaline cleaning agent (manufactured by Yokohama Oil & Fat Co., Ltd., product name: Semi-clean LC-2) at a concentration of 8 mass% was used. The aluminum base pieces used are the same as described for Table 1. Using each aluminum substrate as a mold, a polymer film was produced in the same manner as described in Table 1. The haze value was also measured in the same manner as described for Table 1. FIG. 16 (a) shows an optical microscope image (50 ×) when the surface of the aluminum base material subjected to the alkali cleaning step of Experimental Example 7-1 is observed from the vertical direction, and FIG. 16 (b) and ( c) shows an SEM image (full scale 20 μm in the SEM image) when the surface of the polymer film formed from the aluminum base material of Experimental Examples 7-1 and 7-2 is observed from the vertical direction.

As shown in Table 5 and FIG. 16, when the time of the alkali cleaning step is increased, the convex portions are formed on the surface of the polymer film corresponding to the concave portions due to the galvanic corrosion formed on the aluminum base material. It was confirmed (see FIG. 16C).

Next, an alkali cleaning process and a satin treatment process were performed on the aluminum base material under the conditions shown in Table 6. The aluminum base pieces used are the same as described for Table 1. FIGS. 17A to 17D show optical microscopes when the surface of an aluminum base material having an inverted antiglare structure formed by the matte treatment process of Experimental Examples 8-1 to 8-4 is observed from the vertical direction. Images (50 times) are shown, and FIGS. 17 (e) to 17 (h) show SEMs when the surfaces of the polymer films formed from the aluminum substrates of Experimental Examples 8-1 to 8-4 are observed from the vertical direction. An image (full scale 20 μm in an SEM image) is shown.

In Experimental Examples 8-1 to 8-4, as an alkaline etching solution, an aqueous solution containing an organic alkaline cleaning agent (manufactured by Yokohama Oil & Fat Co., Ltd., product name: Semi-clean LC-2) at a concentration of 12 mass% was used. As the etching solution for the satin treatment, a solution obtained by diluting the etching solution for the satin treatment used in Experimental Example 1-1 twice. In the following table, “same size” or “2 times dilution” for the etchant for the satin treatment is based on the etchant for the satin treatment used in Experimental Example 1-1. Other experimental conditions and evaluation procedures are the same as those described for Table 1. In Table 6, regarding “cutting marks”, “x” indicates that cutting marks were formed on the surface of the aluminum substrate, and “◯” indicates that no cutting marks were formed. “Galvanic corrosion” in Table 6 is “◯” when no galvanic corrosion recess is formed, and “△” when a galvanic corrosion recess is not problematic in practice, but galvanic corrosion. The result of the evaluation is shown as “x” when a concave portion due to is formed and becomes practically problematic. In Table 6, “mass change” is the result of measuring the change in the mass of the aluminum substrate before and after the alkali cleaning step.

As shown in Table 6 and FIG. 17, when the alkali cleaning process was performed for 40 minutes or longer (Experimental Examples 8-2 to 8-4), no cutting trace was formed. On the other hand, when the time of the alkali cleaning step is increased, a concave portion due to galvanic corrosion is formed on the surface of the aluminum base (black portion in the optical microscope image of FIG. 17), and a convex portion is formed in the antiglare film. I can confirm. In particular, when the alkali cleaning step is performed for 60 minutes or longer (Experimental Examples 8-3 and 8-4), it can be confirmed that the density of these is increased.

When a concave portion due to galvanic corrosion is generated on the surface of the aluminum base material 12, a concave portion is also generated corresponding to the surface of the moth-eye mold using the aluminum base material 12. If a recess is formed on the surface of the moth-eye mold due to galvanic corrosion, there is a concern about resin clogging and transferability deterioration. Further, in the antireflection film manufactured using the moth-eye mold, convex portions corresponding to the concave portions due to galvanic corrosion can be formed. Such an antireflection film may be inferior in suppression of glare and scratch resistance. Moreover, since it is difficult to control the position where galvanic corrosion occurs in the aluminum base material 12, it may be difficult to control the haze value of the antireflection film.

In order to solve the above problems, the present inventor has come up with a method for removing at least a part of the work-affected layer of the aluminum base material while suppressing the formation of recesses due to galvanic corrosion.

The aluminum substrate was subjected to an alkali washing step and a satin treatment step under the conditions shown in Table 7 below. In Experimental Example 9-1, an aqueous solution containing an organic alkaline detergent (manufactured by Yokohama Oil & Fats Co., Ltd., product name: Semiclean LC-2) at a concentration of 8 mass% was used as an alkaline etching solution. The alkaline etching solution in Experimental Examples 9-2 to 9-4 was obtained by adding 5 vol% of a corrosion inhibitor (Kiresbit AL, manufactured by Kirest Corp.) as an acidic additive to the alkaline etching solution in Experimental Example 9-1. Is. As a result, the pH of the alkaline etching solution of Experimental Examples 9-2 to 9-4 is lower than the pH of the alkaline etching solution of Experimental Example 9-1. Other experimental conditions are the same as in Table 6.

FIGS. 18A to 18D show optical microscopes when the surface of an aluminum substrate having an inverted antiglare structure formed by the matte treatment process of Experimental Examples 9-1 to 9-4 is observed from the vertical direction. An image (50 times) is shown.

18 (b) to (d) are compared with FIG. 18 (a), it can be seen that the formation of recesses due to galvanic corrosion is effectively suppressed. Further, from Table 7, it is considered that the effects of removing the work-affected layer are the same in Experimental Example 9-1 and Experimental Example 9-2 because there is no difference in the mass change of the aluminum base material in the alkali cleaning step. be able to. That is, by adding an acidic additive to the alkaline etching solution, it was possible to suppress the formation of recesses due to galvanic corrosion while suppressing the formation of cutting marks.

By adding an acidic additive to the alkaline etchant, the pH of the alkaline etchant is reduced. That is, in Experimental Examples 9-2 to 9-4, the action of etching the surface of the aluminum substrate is considered to be weaker than in Experimental Example 9-1. On the other hand, in Experimental Examples 9-2 to 9-4, since it is less likely to be ionized (Al (OH) ₄ ⁻ ) than in Experimental Example 9-1, aluminum hydroxide (Al (OH) ₃ ) is easily formed. It is thought that formation of the recessed part by galvanic corrosion was suppressed by forming aluminum hydroxide on the surface of an aluminum base material.

The acidic additive is not limited to those exemplified, and it can be used as long as it dissolves in an alkaline etching solution and does not corrode aluminum. The corrosion inhibitor (Kiresbit AL) used as an acidic additive in the experimental examples is usually used by adding several percent. In contrast, in the present application, by adding 5 mass% to 10 mass% (see Table 8), it is possible to obtain an alkaline etching solution that suppresses formation of recesses due to galvanic corrosion while suppressing formation of cutting marks. It was.

In FIGS. 18B to 18D, deposits can be confirmed on the surface of the aluminum substrate. This is considered to be a deposit called smut. Smut may be formed when alkaline etching of aluminum is performed, and it is considered that impurities such as Si, Mg, Fe, and Cu contained in the aluminum and alloy components are deposited on the aluminum. It has been. Smut can be removed with an acidic aqueous solution.

Further, in order to investigate the optimum composition of the alkaline etching solution, the same experiment as in Table 7 was performed using the conditions in Table 8. FIGS. 19A to 19D show optical microscopes when the surface of an aluminum substrate having an inverted antiglare structure formed by the matte treatment process of Experimental Examples 10-1 to 10-4 is observed from the vertical direction. Images (50 times) are shown, and FIGS. 19 (e) to 19 (h) show SEMs when the surfaces of the polymer films formed from the aluminum base materials of Experimental Examples 10-1 to 10-4 are observed from the vertical direction. An image (full scale 20 μm in an SEM image) is shown.

As can be seen from Table 8 and FIG. 19, among the experimental examples 10-1 to 10-4, the most effective in the experimental example 10-2 is to suppress the formation of the cutting traces and to prevent the recesses due to galvanic corrosion. The formation could be suppressed.

By adding an acidic additive to the alkaline etching solution, there is an advantage that the time margin for the alkaline cleaning process can be increased. FIG. 20A shows the relationship between the time of the alkali cleaning step and the mass change rate of the aluminum substrate. FIG. 20B shows the relationship between the time of the alkali cleaning step and the haze value of the antiglare film obtained using the aluminum substrate as a mold.

20 (a) and 20 (b) indicate the time (minutes) of the alkali cleaning step. The vertical axis in FIG. 20 (a) represents the rate of change in the mass of the aluminum substrate before and after the alkali cleaning step, that is, (mass before alkali cleaning step−mass after alkali cleaning step) / mass before alkali cleaning × 100. (%). The vertical axis in FIG. 20B indicates the haze value of the antiglare film. 20 (a) and 20 (b), an aqueous solution containing an organic alkaline cleaning agent (Yokohama Yushi Kogyo Co., Ltd., product name: Semi-clean LC-2) at a concentration of 12 mass% is used as an alkaline etching solution. Example 8-1 to 8-4, and an aqueous solution containing an organic alkaline cleaner (Yokohama Yushi Kogyo Co., Ltd., product name: Semi-clean LC-2) as an alkaline etching solution at a concentration of 16 mass%. Examples 10-1 to 10-4 using an aqueous solution containing 10 vol% of a corrosion inhibitor (Kiresbit AL, manufactured by Kirest Co., Ltd.) as an agent, and an organic alkaline cleaner (Yokohama Yushi Kogyo Co., Ltd.) as an alkaline etchant The results of Experiment 11-1 (see Table 9) using an aqueous solution containing the product name: Semi-clean LC-2) at a concentration of 8 mass% It is door.

From FIG. 20 (a), for example, the time taken to reduce the mass of the aluminum base by 0.04% is the concentration of the organic alkaline detergent (Yokohama Yushi Kogyo Co., Ltd., product name: Semi-clean LC-2). Using an aqueous solution containing 12% by mass (Experimental Examples 8-1 to 8-4) takes about 20 minutes, whereas an organic alkaline detergent (product name: Semi-clean LC-2, manufactured by Yokohama Oil & Fats Co., Ltd.) is used. Using an aqueous solution containing 10 vol% of a corrosion inhibitor (Kiresbit AL, manufactured by Kirest Co., Ltd.) as an acidic additive in an aqueous solution containing a concentration of 16 mass% (Experimental Examples 10-1 to 10-4) I understand that there is. It can be seen that by adding an acidic additive to the alkaline etching solution, the time for the alkali cleaning step can be increased.

An acidic additive may be added to the etching solution for the satin treatment. Experiments similar to those in Table 7 were performed using the conditions in Table 9 below. In Experimental Example 11-1, the same etchant as used in Experimental Example 1-1 was used as the etchant for the satin treatment. In Experimental Example 11-2, 10% by volume of a corrosion inhibitor (Kiresbit AL, manufactured by Kirest Co., Ltd.) as an acidic additive was added to the etching solution for the satin processing in Experimental Example 11-1, Used as an etching solution.

FIGS. 21A and 21B show optical microscopes when the surface of an aluminum substrate having an inverted antiglare structure formed by the matte treatment process of Experimental Examples 11-1 and 11-2 is observed from the vertical direction. Images (50 times) are shown, and FIGS. 21C and 21D show SEMs when the surfaces of the polymer films formed from the aluminum substrates of Experimental Examples 11-1 and 11-2 are observed from the vertical direction. An image (full scale 20 μm in an SEM image) is shown.

From Table 9 and FIG. 21, it can be seen that the formation of recesses due to galvanic corrosion is suppressed when an acidic additive is added to the etching solution for the satin treatment. When an acidic additive is added, the texture of the inverted antiglare structure also appears to be slightly rough.

Note that the effects of the above-mentioned etching solution for the satin treatment and the alkaline etching solution are not obtained only in the method for manufacturing the cylindrical moth-eye mold according to the embodiment of the present invention. Since the effect of the etching solution for the satin treatment and the alkaline etching solution does not depend on the shape of the mold, for example, in the manufacturing method of the plate-shaped moth-eye mold, The same effect can be obtained by using an etching solution and an alkaline etching solution.

As described above, the moth-eye that can provide an antireflection function and an antiglare function can be obtained by forming the inverted moth-eye structure using the thus-obtained cylindrical aluminum substrate subjected to the satin treatment. A mold is obtained. When a cylindrical moth-eye mold is used, the antireflection film can be formed by the roll-to-roll method as described above. At this time, in order to improve the adhesion between the film base material (TAC film or PET film) on which the antireflection film is formed and the antireflection film, it is preferable to undergo the following steps.

A UV curable resin containing a solvent (for example, acrylic resin) is applied on the TAC film (thickness is, for example, 2 μm to 20 μm). At this time, as the solvent, a solvent that dissolves the surface of the TAC film (for example, a ketone) is selected. When the solvent dissolves the surface of the TAC film, a region where TAC and the ultraviolet curable resin are mixed is formed.

Thereafter, the solvent is removed, and the TAC film is wound so that the ultraviolet curable resin is in close contact with the outer peripheral surface of the moth-eye mold.

Subsequently, ultraviolet rays are irradiated to cure the ultraviolet curable resin. At this time, the temperature of the ultraviolet curable resin is maintained at 30 ° C. to 70 ° C.

Thereafter, the TAC film is peeled off from the moth-eye mold, and again irradiated with ultraviolet rays as necessary.

When the hard coat layer is formed on the TAC film, the material for forming the hard coat layer may contain a solvent that dissolves the surface of the TAC film. In this case, it is not necessary to add a solvent to the ultraviolet curable resin for forming the antireflection film.

In the case of using a PET film, it is preferable to form a layer (2 μm to 20 μm in thickness) of an aqueous primer (for example, a polyester resin or an acrylic resin) before applying the ultraviolet curable resin. Also in this case, it is not necessary to add a solvent to the ultraviolet curable resin for forming the antireflection film.

The surface treatment method for a substrate according to the present invention is used for a method of manufacturing a mold used for forming an antireflection film (antireflection surface) or the like. The mold manufacturing method according to the present invention is used for manufacturing a mold suitably used for forming an antireflection film (antireflection surface) or the like. The antireflection film manufactured using the mold manufactured by the mold manufacturing method according to the present invention has a surface structure that exhibits an appropriate antiglare function and an excellent antireflection function, for example, a high-definition display. It is suitably used for panels.

DESCRIPTION OF SYMBOLS 10 Type | mold base material 12 Aluminum base material 14 Porous alumina layer 14p Micro recessed part 16 Inorganic material layer 18 Aluminum film | membrane 18r Aluminum residual layer 100 Moss eye type | mold

Claims

A method for treating the surface of a cylindrical or cylindrical substrate,
(A) rotating the base material around the long axis of the base material in a state where the base material is arranged so that the long axis direction of the base material is substantially parallel to the horizontal direction;
(B) A method of treating the surface of a substrate, comprising a step of bringing a part of the outer peripheral surface of the substrate into contact with a first etching solution contained in a first etching tank.
The substrate surface treatment method according to claim 1, further comprising a step (c) of spraying a second etching solution, which is the same as the first etching solution, on the outer peripheral surface of the substrate.
The step (c) is performed simultaneously with the step (b), and the second etching solution is sprayed in the vicinity of the portion in contact with the first etching solution in the outer peripheral surface of the base material. The substrate surface treatment method according to claim 2.
The step (c) is performed simultaneously with the step (a), and the second etching solution is in the vicinity of a portion in contact with the first etching solution in the outer peripheral surface of the base material. The substrate surface treatment method according to claim 2, wherein the substrate is sprayed to a portion rotating in the step (a) so as to move away from the first etching solution.
5. The substrate surface treatment method according to claim 2, wherein in the step (c), the angle at which the second etching solution is ejected is inclined at 45 ° or more and less than 90 ° from the vertical direction. .
6. The substrate surface treatment method according to claim 1, wherein the substrate is an aluminum substrate formed of an Al—Mg—Si based aluminum alloy and mechanically mirror-finished. .
The substrate surface treatment method according to any one of claims 1 to 6, wherein the first etching solution is an aqueous solution containing a salt of hydrogen fluoride and ammonium.
The substrate surface treatment method according to claim 7, wherein the salt of hydrogen fluoride and ammonium is ammonium fluoride.
Before the step (b), the method further includes a step (b1) of bringing a part of the outer peripheral surface of the base material into contact with a third etching solution different from the first etching solution,
The etching rate of the third etching liquid with respect to the outer peripheral surface of the base material is lower than the etching rate of the first etching liquid with respect to the outer peripheral surface of the base material. Surface treatment method.
The substrate surface treatment method according to claim 9, wherein the third etching solution is an etching solution obtained by diluting the first etching solution.
The surface treatment method for a substrate according to claim 9 or 10, wherein the third etching solution is at a lower temperature than the first etching solution.
The surface treatment method for a substrate according to any one of claims 9 to 11, wherein the third etching solution is accommodated in a second etching tank different from the first etching tank.
The surface treatment method for a substrate according to any one of claims 9 to 11, wherein the third etching solution is accommodated in the first etching tank.
After the step (b), the method further includes a step (b2) of bringing a part of the outer peripheral surface of the base material into contact with a fourth etching solution different from the first etching solution,
The etching rate with respect to the outer peripheral surface of the said base material of the said 4th etching liquid is lower than the etching rate with respect to the outer peripheral surface of the said base material of the said 1st etching liquid of the base material in any one of Claim 1-13 Surface treatment method.
15. The substrate surface treatment method according to claim 14, wherein the fourth etching solution is the same etching solution as the third etching solution.
The substrate surface treatment method according to any one of claims 1 to 15, wherein in the step (a), the peripheral speed of the substrate is greater than 0 m / s and not greater than 0.03 m / s.
The substrate surface treatment method according to any one of claims 1 to 16, wherein in the step (a), the rotation speed of the substrate is more than 0 rpm and 2 rpm or less.
(A) a step of preparing a cylindrical aluminum base material formed of an Al—Mg—Si-based aluminum alloy and mechanically mirror-finished;
(B) The process of processing the surface of the said aluminum base material by the surface treatment method in any one of Claims 1-17,
(C) after the step (B), forming an inorganic material layer on the surface of the aluminum substrate, and forming an aluminum film on the inorganic material layer, thereby producing a mold substrate; ,
(D) after the step (C), anodizing the surface of the aluminum film to form a porous alumina layer having a plurality of micro-recesses;
(E) After the step (D), the step of enlarging the plurality of micro concave portions of the porous alumina layer by bringing the porous alumina layer into contact with an etching solution;
(F) After the said process (E), the process of growing the said several micro recessed part by further anodizing, The manufacturing method of a type | mold.
The method for producing a mold according to claim 18, further comprising a step (G) of etching the surface of the aluminum base using an alkaline etching solution before the step (B).
20. The mold manufacturing method according to claim 19, wherein the pH of the alkaline etching solution is 8 or more and 10 or less.
The method for producing a mold according to claim 19 or 20, wherein the alkaline etching solution is prepared by adding an acidic additive to an aqueous solution containing an organic compound having an amino group.
The method for producing a mold according to claim 21, wherein the volume of the acidic additive is 5% or more with respect to the volume of the aqueous solution containing the organic compound having an amino group.