JP5742098B2 - Method for producing mold for production of antireflection film - Google Patents

Description

  The present invention relates to a method for producing a mold for producing an antireflection film used for producing a moth-eye type antireflection film used for a flat panel display or the like.

  In recent years, with the development of personal computers, in particular with the development of portable personal computers, the demand for flat panel displays has increased. Recently, the penetration rate of flat-panel televisions for home use is also increasing, and the market for flat panel displays is expanding. Furthermore, flat panel displays that have become widespread in recent years tend to have larger screens, and this tendency is particularly strong for home-use liquid crystal televisions. As such a flat panel display, various display methods such as a liquid crystal display, a plasma display, and an organic EL display are adopted, and the display quality of the image is improved in any display. The purposeful research is done every day. In particular, the development of anti-reflection technology for the purpose of improving display quality has become one of the important technical issues common to each type of display.

  Conventionally, as such an antireflection technique, for example, a technique of obtaining an antireflection effect effective for light of a single wavelength by forming a thin film made of a low refractive index material on the surface as a single layer, A technique for obtaining an antireflection effect for light in a wider wavelength range by forming a plurality of layers in which thin films of a low refractive index substance and a high refractive index substance are alternately formed has been used. Among them, the technique using a plurality of layers has been useful in that an antireflection effect can be obtained even for light having a wider wavelength range by increasing the number of layers. It has been put to practical use.

However, there are some problems in such a technique using a plurality of layers. First, in order to form a plurality of layers having an excellent antireflection effect, it is usually necessary to form a film using a vacuum deposition method or the like, and therefore it is necessary to provide a vacuum facility when manufacturing a display device. There was a problem of becoming. Further, in the vacuum deposition method, since the film formation time is generally long, a problem of manufacturing efficiency has been pointed out. In particular, for displays used in environments with very strong ambient light, higher antireflection performance is required, so the number of layers that make up multiple layers must be increased, resulting in significant manufacturing costs. There was a problem of becoming high.
Second, even from a technical point of view, the antireflection technology using multiple layers uses the light interference phenomenon, so that the antireflection effect greatly affects the incident angle and wavelength of light, as desired. There is a problem that it is difficult to obtain the antireflection effect.

In order to deal with such problems, Patent Documents 1 to 6 disclose techniques for preventing reflection by forming on the surface a fine uneven pattern in which the uneven period is controlled to be equal to or less than the wavelength of visible light. Such a method uses the principle of a so-called moth-eye structure, and continuously changes the refractive index for light incident on the substrate, thereby eliminating the discontinuous interface of the refractive index. This prevents light reflection. Such antireflection technology using a moth-eye structure is useful in that it can prevent reflection of light in a wide wavelength range by a simple method, and its practical application is also being studied in the field of displays. .
In addition, as a concavo-convex pattern used for the moth-eye structure, a cone-shaped body such as a cone or a quadrangular pyramid is generally used.

  The moth-eye structure is generally manufactured by transferring the irregularities to an arbitrary resin layer using a mold (stamper or mold) having a shape obtained by inverting the fine irregularities. Therefore, as a method for producing an antireflection film using a moth-eye structure (hereinafter sometimes referred to as “moth-eye type antireflection film”), after forming a resin layer made of a curable resin on a substrate, A method of forming a moth-eye structure on the surface of the resin layer using the stamper as described above and further curing the resin layer can be used. Such a production method has an advantage that an antireflection film can be continuously produced by a simple method and high production efficiency.

  By the way, the moth-eye structure is generally manufactured by transferring the concave / convex mold to an arbitrary resin layer using a stamper (mold or mold) having a shape obtained by inverting the fine concave / convex shape. As a matter of fact, as the stamper, those having recesses formed by a laser interference method (for example, Patent Documents 1 to 3) and those having recesses formed by an anodic oxidation method (for example, Patent Documents 4 to 6). Is used. Among them, the anodic oxidation method has advantages in that the position where the concave portion is formed can be made random and the concave portion having a uniform shape over a large area can be formed. Those formed by the anodic oxidation method have come to be widely used, and researches with an eye toward improving the recess formation technology are still actively conducted.

  When forming a mold by such an anodic oxidation method, the concave portion to be formed depends on the surface state of the metal substrate. Therefore, the metal substrate having a uniform surface such as a crystal state or a surface shape is selected. It has been essential to use it. That is, if the surface state is non-uniform, the micropores formed correspondingly become non-uniform, and there is a problem that a desired mold cannot be manufactured. For this reason, as the metal substrate, an expensive homogeneous material, or an aluminum substrate on which an aluminum vapor deposition film, a sputtered film or the like is formed has been used. However, the metal substrate on which the deposited film or the like is formed as described above has an advantage that the surface aluminum has high purity and the surface smoothness is excellent, but a large substrate is processed due to the limitation of the size of the vacuum equipment. This is difficult or expensive, and it is difficult to form a film uniformly on a curved substrate from the film formation method. Furthermore, it has been a problem that the deposited film is peeled off from the substrate. Moreover, since it is necessary to perform the process of forming a vapor deposition film separately, there also existed a problem that a manufacturing process will become remarkably complicated.

  On the other hand, chemical polishing is one method for removing the surface of a non-uniform metal substrate, but this has the problem that the metal substrate cannot be removed smoothly. Further, as described in Patent Document 5, there is a method in which after anodizing once, an immersion treatment in a mixed aqueous solution of phosphoric acid and hexavalent chromic acid is performed, and anodizing is again performed in order. Divalent chromic acid is a highly toxic substance, and a safer method has been desired.

JP 2001-264520 A JP 2002-172722 A JP 2002-333508 A JP 2003-43203 A JP 2005-156695 A International Publication No. 2006/059686 Pamphlet

  The present invention has been made in view of such problems, and even when a metal substrate having a non-uniform crystal state or surface shape is used, an antireflection film in which uniform fine holes are formed by an anodic oxidation method is manufactured. The main object of the present invention is to provide a method for producing a mold for producing an antireflection film capable of producing a mold for production.

In order to solve the above-mentioned problems, the present invention uses a metal substrate containing aluminum and having a non-uniform layer in which the crystal state or surface shape is non-uniform on the surface, and the surface of the metal substrate is subjected to anodization. A porous alumina film forming step for forming an alumina film having micropores and an etching step for enlarging the pore diameter of the micropores by etching the alumina film are sequentially repeated to form micropores on the surface of the metal substrate. A method for producing a mold for producing an antireflection film, comprising a step of forming micropores,
The heterogeneous layer is at least one selected from a work-affected layer generated by polishing the surface, a microporous surface layer partially chipped, and a surface layer to which foreign matter has adhered,
The porous alumina film forming step is a step of anodizing at a voltage of 60 V for 5 minutes using a 0.1% oxalic acid aqueous solution,
What der which the etching process etches a portion of the alumina film, a step of etching 5 minutes at 50 ° C. with 10% phosphoric acid aqueous solution,
The method for producing a mold for producing an antireflection film is characterized in that the fine hole forming step involves etching of the metal substrate at least more than the thickness of the non-uniform layer .

  According to the present invention, the fine hole forming step sequentially repeats the porous alumina film forming step and the etching step, and the etching step is an alumina formed by the porous alumina film forming step. Reflection in which uniform micropores are formed even when the metal substrate having the non-uniform layer is used because it etches part of the film and does not remove all of the alumina film. A mold for producing the prevention film can be produced.

In the present invention, the fine hole forming step involves etching the metal substrate at least more than the thickness of the non-uniform layer . This is because a mold for producing an antireflection film in which more uniform micropores are formed can be produced by the present invention.

  INDUSTRIAL APPLICABILITY The present invention has an effect that even when a metal substrate having a non-uniform crystal state and surface shape is used, a mold for producing an antireflection film in which uniform fine holes are formed by an anodic oxidation method can be produced. .

It is the schematic which shows an example of the preparation methods of the metal mold | die for antireflection film manufacture of this invention. It is the schematic which shows another example about the preparation methods of the metal mold | die for antireflection film manufacture of this invention. It is the schematic which shows another example about the preparation methods of the metal mold | die for antireflection film manufacture of this invention. It is the schematic explaining the parameter which specifies the moth-eye structure part in this invention.

  Hereinafter, the production method of the mold for producing the antireflection film of the present invention will be described in detail.

  As described above, the method for producing a mold for producing an antireflection film of the present invention uses a metal substrate containing aluminum and having a non-uniform layer in which the crystal state or surface shape is non-uniform on the surface, A porous alumina film forming step for forming an alumina film having micropores on the surface of the metal substrate by anodization and an etching step for expanding the micropore diameter by etching the alumina film are sequentially repeated. Thus, there is provided a method having a micropore forming step for forming micropores on the surface of the metal substrate, wherein the etching step etches a part of the alumina film.

A method for producing such a mold for producing an antireflection film of the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic view showing an example of a method for producing a mold for producing an antireflection film of the present invention. As illustrated in FIG. 1, the method for manufacturing a mold for manufacturing an antireflection film according to the present invention uses a metal substrate 1 (FIG. 1A), and performs a micropore forming process for the metal substrate 1. (FIGS. 1B and 1C) are used to manufacture a mold for manufacturing an antireflection film having a structure in which uniform fine holes are formed on the surface of the metal substrate 1 (FIG. 1D). ).
Here, in the method for producing a mold for producing an antireflection film of the present invention, the micropore forming step includes a porous alumina film forming step in which an alumina film having micropores is formed on the surface of the metal substrate (FIG. 1 ( b)), etching the alumina film to enlarge the hole diameter of the fine holes, and repeating the steps (FIG. 1 (c)) to form the fine holes.

  That is, in the fine hole forming step, a porous alumina film forming step for forming an alumina film X having fine holes on the surface of the metal substrate 1 by anodic oxidation with respect to the metal substrate 1 (FIG. 1A) ( 1 (b)), an etching process for expanding the diameter of the micropores by etching the alumina film X (FIG. 1 (c)) and a method of repeating this sequentially are used. By adjusting the anodic oxidation time in the porous alumina film forming step and the etching processing time in the etching step, it is possible to form holes having various tapered shapes, matching the period and hole depth. This is because an optimum refractive index change can be designed (FIG. 1 (d)).

  In such an example, the method for producing a mold for producing an antireflection film of the present invention includes a porous alumina film forming step of forming an alumina film X having fine holes on its surface (FIG. 1B), and the alumina film X And the etching step (FIG. 1 (c)) is carried out sequentially and the etching step (FIG. 1 (c)) is performed in the porous alumina film. A part of the alumina film X formed by the forming step (FIG. 1B) is etched, and the whole of the alumina film X is not removed.

Here, the fact that the etching process is for etching a part of the alumina film X means that the surface made of metallic aluminum is never exposed to the outermost surface in the fine hole forming process. It is.
And in this invention, it is preferable that the thickness etched in the said micropore formation process is more than the thickness of a nonuniform layer at least. In other words, this means that the non-uniform layer 1a originally present in the metal substrate 1 is all removed in the fine hole forming step.

  According to the present invention, the fine hole forming step sequentially repeats the porous alumina film forming step and the etching step, and the etching step is an alumina film formed by the porous alumina film forming step. Anti-reflection in which uniform fine holes are formed even when the metal substrate having the non-uniform layer is used by etching a part of the metal layer and not removing the entire alumina film. A mold for film production can be produced.

As described above, in the present invention, the porous alumina film forming step and the etching step are repeatedly performed, and at that time, the alumina film is not completely removed in the etching step, and a uniform fine hole is formed by removing only a part. This is because self-organization can be promoted in anodic oxidation by repeatedly performing the porous alumina film forming step and the etching step.
That is, for example, as illustrated in FIG. 2, the porous alumina film forming step and the etching step are repeatedly performed a plurality of times, so that the shape of the fine holes initially formed by anodization due to the influence of the non-uniform layer Even if the arrangement becomes non-uniform, the shape and arrangement of the micropores that are formed gradually become uniform as the process is repeated, and finally uniform micropores can be formed. (In FIG. 2, (a), (c), and (e) represent a porous alumina film forming step, and (b), (d), and (f) represent an etching step).

  Also, the reason for not exposing the metal aluminum surface in the etching process is that metal aluminum is more easily etched than alumina, so if the metal aluminum surface is exposed in the etching process, the etching progress of the exposed part is accelerated, This is because the etching is performed non-uniformly, so that the formation of uniform micropores is hindered.

The method for producing a mold for producing an antireflection film according to the present invention includes a micropore forming process including at least the porous alumina film forming process described above and an etching process, and other optional processes may be performed as necessary. It may be used.
Hereafter, each process used for this invention is demonstrated in order.

1. Micropore formation step First, the micropore formation step used in the present invention will be described. As described above, this process uses a metal substrate containing aluminum and having a non-uniform layer with a non-uniform crystal state or surface shape on the surface, and has fine pores on the surface of the metal substrate by anodic oxidation. A step of forming micropores on the surface of the metal substrate by sequentially repeating a porous alumina film forming step of forming an alumina film and an etching step of enlarging the pore diameter of the micropores by etching the alumina film. It is. And the said etching process etches a part of said alumina film | membrane, It is characterized by the above-mentioned.

(1) Metal substrate First, the metal substrate used in this step will be described. The metal substrate used in this step is not particularly limited as long as it contains aluminum and a non-uniform layer is formed on the surface. Here, examples of the non-uniform layer in the present invention include a layer having a non-uniform crystal state or surface shape. Crystalline state is uneven as a non uniform layer, for example, Ru can be mentioned aspect of a distribution of grain boundaries. Further, if the surface shape is not uniform, the surface of Ru can or contains a flaw not smooth, or the micropores illustrate aspects of them being unevenly formed. Specific examples of the non-uniform layer include, for example, a work-affected layer produced by polishing the surface, a microporous surface layer that is partially chipped and adhered to foreign matter, a surface layer that contains foreign matter attached and mixed, and impurities. The surface layer and the surface layer which carried out the chemical reaction unevenly can be mentioned. For this reason, for example, used antireflection film molds that have non-uniform micropores formed on the surface are also included in the metal substrate used in the present invention. .

  The nonuniform layer in the present invention is preferably etched in this step. Thereby, the thickness of the non-uniform layer does not affect the performance of the mold for producing an antireflection film produced according to the present invention. Therefore, any metal substrate containing aluminum can be used as the metal substrate regardless of the thickness of the nonuniform layer. However, if the thickness of the non-uniform layer is too large in the metal substrate used in this step, the number of repetitions of the porous alumina film forming step and the etching step described later may be excessive in order to remove the non-uniform layer. There is. From such a viewpoint, the thickness of the non-uniform layer is preferably as thin as possible.

  Here, the thickness of the non-uniform layer can be measured by a method according to the mode of the non-uniform layer. For example, when the heterogeneous layer is the above-mentioned work-affected layer, it is described in X-ray diffraction method, electron beam diffraction method, ultrasonic microscope method, oblique polishing method, and JP-A-2008-2369 or JP-A-2002-187788. Can be evaluated by When the non-uniform layer has a non-uniform surface shape such as partial chipping, it can be evaluated by AFM, SEM or the like. Further, when the non-uniform layer is a surface layer on which foreign matter is adhered and mixed, it can be evaluated by a microscope, AFM, SEM, or white interferometer. Furthermore, when the heterogeneous layer is a layer containing impurities and a chemically reacted layer, it can be evaluated by various component analysis (for example, XPS, EDX, SIMS, FT-IR, etc.).

  The metal substrate used in this step is not particularly limited as long as it contains aluminum. Therefore, the metal substrate used in this step may be composed of aluminum alone, or has a configuration in which an aluminum layer is formed on an arbitrary substrate so that it is the outermost layer. May be. Moreover, the metal base | substrate used for this invention should just contain aluminum, and may contain impurities, such as aluminum oxide other than aluminum, for example.

  Moreover, the form of the metal substrate used in this step is not particularly limited. Therefore, in this step, a metal substrate having either a sheet shape or a roll shape can be preferably used.

(2) Porous alumina film forming step Next, the porous alumina film forming step used in this step will be described. This step is a step of forming an alumina film having fine holes on the surface of the metal substrate. In this step, the method for forming an alumina film having micropores on the surface of the metal substrate is not particularly limited as long as it can form an alumina film having micropores in a desired depth and arrangement. It is not something. Here, the depth and arrangement of the micropores formed in the porous alumina film forming step depend on the liquidity of the electrolytic solution used for anodic oxidation, and the electrolytic solution used in this step is medium. Even if it is an acidic electrolytic solution or an acidic electrolytic solution, it can be suitably used. In particular, in this step, it is preferable to use an acidic electrolytic solution as the electrolytic solution. This is because by using an acidic electrolytic solution, micropores can be formed at random positions on the surface of the mold base in this step. Examples of the acidic electrolytic solution used in this step include a sulfuric acid aqueous solution, an oxalic acid aqueous solution, and a phosphoric acid aqueous solution.

(3) Etching process Next, the etching process used for this process is demonstrated. This step is a step of expanding the diameter of the micropores by etching the alumina film. Here, this step is characterized in that a part of the alumina film formed by the porous alumina film forming step is etched and not all of the alumina film is removed.

  In this step, the method for etching the alumina film is not particularly limited unless it is a method for expanding the micropores formed in the alumina film to a desired level and further removing all the alumina film. Examples of such a method include an alkali etching method, an acidic etching method, and an electrolytic etching method. The etching conditions may be arbitrarily adjusted as long as the alumina film is not completely removed. Although any of these methods can be used in the etching step, the alkali etching method has a large gloss, surface roughness, etc., and it is difficult to maintain the etching surface in a constant state, and the free alkali concentration It is preferable to use an acidic etching method because it is required to always control the dissolved aluminum component in the bath in a certain range.

(4) Micropore forming step In this step, the degree of repetition when the porous alumina film forming step and the etching step are repeated is uniform enough to be used as a mold for manufacturing an antireflection film. The process is repeated several times until a fine hole can be formed.
In the present invention, it is particularly preferable that the process is repeated a plurality of times to such an extent that the surface of the metal substrate can be etched beyond the thickness of the non-uniform layer present on the surface of the metal substrate used in this step. Thereby, uniform micropores can be reliably formed on the surface, and a high quality antireflection film manufacturing mold can be obtained.

  In this step, it is preferable to repeat the porous alumina film forming step and the etching step so that tapered fine holes can be formed on the surface of the metal substrate. The mold for producing an antireflective film produced by the present invention is used for producing a so-called antireflective film. By forming the shape of the recess formed in this step into a tapered shape, the present invention This is because it is possible to impart an excellent antireflection function in a wide wavelength region to the antireflection film produced using the mold for producing the moth-eye type antireflection film produced by the above method.

  FIG. 3 is a schematic view showing an example of an embodiment in which the porous alumina film forming step and the etching step are repeatedly performed so that tapered fine holes are formed in this step. As exemplified in FIG. 3, in this step, the first cylindrical alumina film forming step is performed on the metal substrate 1 having the heterogeneous layer 1 a (FIG. 3A) first to form a cylindrical first After the formation of the alumina film X having micropores (FIG. 3B), the alumina film X is etched by the first etching process so as to enlarge the diameter of the first micropores (FIG. 3). (C)). Next, in the second porous alumina film forming step, second micropores having a pore diameter smaller than that of the first micropores are formed at the bottoms of the first micropores having the enlarged pore diameters (FIG. 3D )). Next, the alumina film X is etched by the second etching step so as to enlarge the diameters of the first and second micro holes (FIG. 3E). By repeating this several times (FIGS. 3 (f) and 3 (g)), it is preferable to form a fine hole having a tapered shape (FIG. 3 (h)). And the micropore forming process in the present invention is a process in which the nonuniform layer 1a originally present on the surface of the metal substrate is finally removed, and the porous alumina film forming process and the etching process are repeated. The metal aluminum layer in which the alumina film X is not formed is prevented from being exposed to the outermost layer.

  In this step, the number of times the porous alumina film forming step and the etching step are repeatedly performed is appropriately determined according to the thickness of the non-uniform layer formed on the metal substrate, the shape of the target micropore, and the like. Is not particularly limited. Here, the thickness of the metal substrate to be etched in this step may be at least equal to or greater than the thickness of the non-uniform layer, but is preferably not less than the thickness of the non-uniform layer + 0.5 μm. It is preferable that the thickness is +1.0 μm or more. This is because a mold for producing an antireflection film in which more uniform micropores are formed can be produced by the present invention. In this step, the number of times the porous alumina film forming step and the etching step are repeatedly performed is appropriately adjusted together with the etching conditions according to the target etching amount.

The period of the micropores formed in the metal substrate by this process is not particularly limited, depending on the use of the antireflection film produced using the antireflection film production mold produced by the present invention. It can be determined as appropriate. Here, the period in which the micropores are formed in this step affects the wavelength dependence of the reflectance of the antireflection film produced using the antireflection film production mold produced according to the present invention. There is a tendency that as the period becomes longer, the reflectance with respect to light on the short wavelength side in the visible light region increases. On the other hand, when the period is 200 nm or less, the change in the wavelength dependence of the reflectance due to the fluctuation of the period is small. For these reasons, the period of the micropores formed in this step is preferably in the range of 70 nm to 130 nm, and more preferably in the range of 90 nm to 110 nm.
In addition, although the said period may not be uniform in all the micropores, it shall refer to the average period of the micropore formed per unit area in that case.

  In addition, the average hole depth of the fine holes formed in this step also affects the wavelength dependence of the reflectance of the antireflection film produced using the antireflection film production mold produced according to the present invention. As the depth increases, the reflectance can be lowered. On the other hand, when the depth becomes shallower, the reflectance on the long wavelength side tends to increase. For this reason, the average pore depth of the micropores formed in this step is preferably in the range of 150 nm to 450 nm, and more preferably in the range of 250 nm to 350 nm.

In addition, in the antireflection film manufactured using the antireflection film manufacturing mold manufactured according to the present invention, the spacing between the micropores formed in this step becomes wider, and the reflectance in the entire wavelength region of visible light is higher. There is a tendency to increase, and as it becomes narrower, the reflectance tends to decrease in the entire wavelength region of visible light. For this reason, the interval at which the micropores are formed in this step is preferably in the range of 0 nm to 30 nm, and more preferably in the range of 10 nm to 20 nm.
In addition, although the said space | interval may not be uniform in all the micropores, the said space | interval in that case shall point out the average distance between the micropores formed per unit area.

  Here, the period, depth, and interval at which the fine holes are formed are distances represented by P, Q, and R in FIG.

2. Arbitrary process The manufacturing method of the metal mold | die for antireflective film manufacture of this invention has the said micropore formation process at least, and may have another arbitrary processes as needed.

3. Applications The method for producing a mold for producing an antireflection film of the present invention can be used as a method for newly producing a mold for producing a moth-eye type antireflection film. The antireflection film produced using the mold for producing the antireflection film produced according to the present invention is usually used by being disposed on the outermost surface of a display device or the like. However, the moth-eye structure formed on the surface of the anti-reflection film not only has an anti-reflection function, but improves the adhesion to the arbitrary layer when an arbitrary layer is formed on the moth-eye structure, for example, by an anchor effect. The function of making it possible can also be achieved. For this reason, the use of the antireflection film produced by using the antireflection film production mold produced according to the present invention is not limited to the use disposed on the outermost surface of the display device as described above, For example, it may be arranged in an optical member having a configuration in which a plurality of layers are laminated, and may be used in an aspect that exhibits an antireflection function and an adhesion improving function by the anchor effect.

  The method for producing a mold for producing an antireflection film of the present invention can also be used as a method for regenerating a mold for producing an antireflection film that has been used. That is, in the used antireflection film manufacturing mold, the micropores formed on the surface become non-uniform, and the performance of the manufactured antireflection film deteriorates if it is used continuously. It will be. Therefore, the method of the present invention is used by using the used antireflection film production mold as the metal substrate in the present invention, and the region where the non-uniform fine holes are formed as the non-uniform layer in the present invention. By carrying out the step, the micropores can be made uniform again and reused. For this reason, the manufacturing method of the metal mold | die for antireflection film manufacture of this invention can be used also as a reproduction | regeneration method of a metal mold | die.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be specifically described by giving examples.

[Example 1]
Using an A1000 series aluminum plate whose surface was modified by grinding as a metal substrate, anodization was performed for 5 minutes at a voltage of 60 V with 0.1% oxalic acid aqueous solution (porous alumina film forming step) ). Next, etching (etching process) was performed at 10% phosphoric acid aqueous solution at 50 ° C. for 5 minutes. This anodizing process and etching process are repeated 19 times to carry out a micropore forming process, forming a porous aluminum oxide film surface having a conical hole shape while removing a non-uniform layer on the surface of the metal substrate, and reflecting A mold for producing the prevention film was obtained.
Here, the thickness of the non-uniform layer of the metal substrate was 1 μm at the maximum, whereas the thickness of the metal substrate etched in the fine hole forming step was 1 μm.

  The non-uniform layer is a work-affected layer when the aluminum surface is ground, and since the hardness is higher than that of unprocessed aluminum, the thickness of the work-affected layer can be measured by hardness measurement. The depth of the deteriorated layer was measured by measuring and comparing the indentation depth-weighting curves of aluminum with a modified layer and aluminum without a modified layer with a micro hardness meter PICODENTOR HM500 (Fischer Instruments).

[ Reference Example 2]
In the same manner as in Example 1, the porous alumina film forming step and the etching step were repeated 6 times to perform the fine hole forming step, thereby obtaining a mold for producing an antireflection film. The thickness of the metal substrate etched in the fine hole forming step was 0.3 μm.

[Example 3]
As a metal substrate, a mold having a chip on the surface by use (the chip size is about 100 nm) was used, and anodization was performed for 5 minutes with a voltage of 60 V with 0.1% oxalic acid aqueous solution (porous alumina film) Forming step). Next, etching was performed for 5 minutes at 10% phosphoric acid aqueous solution at 50 ° C. (etching step). This anodization and etching process is repeated 5 times to carry out a micropore formation process, and a porous alumina film surface having a conical pore shape is formed while removing a chipped surface. A production mold was obtained.

[Evaluation]
The antireflection film production molds obtained in Examples 1 and 3 and Reference Example 2 were observed with an SEM. Moreover, the moth-eye film was manufactured using the metal mold | die for antireflection film manufacture obtained in the said Example, and the reflectance was measured.

(Preparation of composition for producing antireflection film)
In a 1-liter glass container, 15 parts of pentaerythritol triacrylate / HDI nurate (Desmodur N3300 manufactured by Sumika Bayer Urethane Co., Ltd., “HDI” represents hexamethylene diisocyanate), 35 parts of polyethylene glycol diacrylate, 1,4-butanediol diacrylate (functional group number: 2, molecular weight: 198, Tg: 45 ° C., SR213 Sartomer) 50 parts, photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, Irgacure 184, Ciba Specialty Chemicals) 5 parts, 0.6 parts slip agent (perfluoroalkylethylene oxide adduct, Megafac F443, manufactured by DIC Corporation) is added and stirred with a de-spacer (temperature 50 ° C. to 60 ° C., stirring time) 30 minutes), reflection of the present invention To obtain a stop film composition for producing.

(Preparation of antireflection film)
The above composition was discharged into the antireflection film production mold obtained in Examples 1 and 3 and Reference Example 2, and a triacetyl cellulose film (Fujitac T80SZ, Fuji Film) having a thickness of 80 μm, length of 30 cm, and width of 30 cm. 1 side of the product manufactured by Co., Ltd. is covered with a mold for producing an antireflection film on which the above composition has been discharged, and is pressed with a load of 0.35 MPa using a rubber roller to reflect the triacetylcellulose film and the reflection. It was confirmed that the composition existing between the molds for producing the prevention film spread uniformly, and the coating layer was irradiated with an ultraviolet irradiation device (manufactured by Fusion UV Systems) with an irradiation distance of 0 cm and an irradiation intensity of 200 mW / cm ^2. Then, under the condition of a conveyance speed of 2.5 m / s, the ultraviolet ray was irradiated through the triacetyl cellulose film to perform a curing treatment. Immediately after curing, the triacetylcellulose film was peeled from the mold for producing the antireflection film to obtain an antireflection film provided with an antireflection layer.

(Measurement of reflectance)
Based on the method described in JIS Z 8722, measurement was performed using a spectrocolorimeter CM-2600d manufactured by Konica Minolta Sensing. For measurement, the measurement light is incident at an angle of 8 ° with respect to the normal of the mold surface, so that the spectral reflectance (SCI) including the regular reflection light on the mold surface and the regular reflection light on the mold surface are measured. After measuring the spectral reflectance (SCE), the spectral reflectance (SCE) obtained by removing the regular reflection light on the mold surface from the spectral reflectance (SCI) including the regular reflection light on the mold surface. Reflectance was obtained by subtracting.

(result)
The surface of the metal mold for producing the antireflection film obtained in Example 1 and Example 3 in which the metal substrate was etched beyond the thickness of the heterogeneous layer was a porous aluminum oxide film surface having a uniform conical hole shape. The reflectance ((Y) value (%)) of the antireflection film using the mold for producing the antireflection film was 0.18%. The surface of the mold of Reference Example 2 in which the metal substrate having a thickness equal to or less than the thickness of the nonuniform layer was etched had a nonuniform portion, and the reflectance of the film using the mold was 2.58%. This confirmed that Examples 1 and 3 were useful as antireflection films.

DESCRIPTION OF SYMBOLS 1 ... Metal substrate 1a ... Nonuniform layer X ... Alumina film

Claims (1)

Porous alumina containing a metal base having a non-uniform layer containing aluminum and having a non-uniform crystal state or surface shape, and forming an alumina film having fine pores on the surface of the metal base by anodic oxidation A reflection step having a micropore formation step of forming micropores on the surface of the metal substrate by sequentially repeating a film formation step and an etching step of enlarging the pore diameter of the micropores by etching the alumina film A method for producing a mold for producing a prevention film,
The heterogeneous layer is at least one selected from a work-affected layer generated by polishing the surface, a microporous surface layer partially chipped, and a surface layer to which foreign matter has adhered,
The porous alumina film forming step is a step of anodizing at a voltage of 60 V for 5 minutes using a 0.1% oxalic acid aqueous solution,
What der which the etching process etches a portion of the alumina film, a step of etching 5 minutes at 50 ° C. with 10% phosphoric acid aqueous solution,
The method for producing a mold for producing an antireflection film, wherein the fine hole forming step involves etching of the metal substrate at least more than the thickness of the non-uniform layer .

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