JP5088778B2 - Manufacturing method of surface processed substrate having fine uneven surface - Google Patents

Description

  The present invention relates to a method for producing a surface-treated substrate having a fine uneven surface and a solar cell substrate comprising the surface-treated substrate produced by the method.

  In recent years, thin film solar cells have been actively developed in order to promote the widespread use of solar power generation by reducing manufacturing costs. In order to improve the energy conversion efficiency of the thin-film solar cell, fine irregularities are formed on the surface of the substrate in order to efficiently use sunlight, and sunlight is repeatedly reflected inside the power generation element. In addition, a display device such as a liquid crystal display has an antiglare layer for diffusing reflected light. This antiglare layer is usually composed of a resin film having a fine uneven surface. There is also a matte paint that forms fine irregularities on the surface to improve the design of the product. In addition, the resin film having a fine uneven surface may be used in the bio field such as cell culture dishes. Therefore, various techniques for forming fine irregularities on the surface of a resin film or the like have been studied so far.

  For example, in Patent Document 1, a resin solution is applied on a support substrate and dried to form a fine particle capturing layer, and then a fine particle dispersion is applied and dried thereon to form a fine particle deposition layer. A method for embedding a fine particle deposition layer by melting and forming a fine uneven pattern is disclosed. At this time, by setting the thickness of the trapping layer to be equal to or smaller than the average particle diameter of the fine particles, only the lowermost fine particles are embedded in the thin film, and if the fine particles are removed, fine irregularities are formed on the substrate. Yes. There is a description that fine particles can be arranged at a high packing density if spherical particles having a high roundness and a narrow particle size distribution are used as the fine particles.

  However, according to Patent Document 1, the particle diameter of the fine particles used is 3 nm to 5 μm, and the film thickness of the trapping layer is less than this. In this way, it is very difficult to form a very thin trapping layer of several μm or less with a large area and a uniform thickness, and the cost becomes extremely high. Moreover, it is technically difficult to industrially manufacture such a thin film. Furthermore, in the technique of Patent Document 1, the resin deposition layer is embedded by melting the resin, but it may be technically difficult to form a uniform and fine uneven surface by such a method. The reason is as follows.

  In the case of melting a resin, Patent Document 1 states that the depth at which fine particles are embedded is shallower than the particle diameter. However, the molten resin is sucked up to the inside of the fine particle deposition layer by the surface tension, and there is a possibility that the amount and height of the molten resin that crawls up on the fine particles vary depending on the size of the fine particles. Therefore, in order to make the embedding depth of the fine particles smaller than the particle radius as in the example of Patent Document 1, the particle diameter of the fine particles must be controlled extremely uniformly and the amount of resin applied as the trapping layer must be adjusted strictly. I must. Otherwise, unevenness in the thickness of the resin and abnormal protrusions may occur, and the yield may be deteriorated.

  In Patent Document 2, as a substrate for a solar cell in which fine irregularities are regularly arranged, a polyimide solution in which fine particles are dispersed and a simple polyimide solution are supplied to a two-layer die, and the polyimide solution side in which fine particles are dispersed is smooth. A method for producing a bilayer film in contact with a support is disclosed.

  However, according to the method of Patent Document 2, there is a high possibility that fine particles are exposed to the film surface in an unstable manner no matter how smooth a support is used, and abnormal defects may occur due to this falling off due to rubbing or the like. In this method, if the concentration of the fine particles in the polyimide solution is increased, the film becomes brittle and the strength decreases.

  In Patent Document 3, a liquid paint is applied on a substrate, particles are attached or buried while the liquid paint is uncured, and the paint film is roughened by removing the particles after the paint is cured. A method is described. Since the particles are removed by this method, the particles do not fall off later as in the technique of Patent Document 2. However, it is extremely difficult to adhere the particles to the uncured coating film with high regularity. For example, it is substantially impossible to transfer the unevenness of the layer in which the particles are regularly arranged in a close packing manner.

In Patent Document 4, an organic resin material and a material that is incompatible with the material are mixed to form a coating liquid, and after the coating liquid is applied and cured, the coating film is removed by removing the incompatible material. A method for forming irregularities on the surface is disclosed. However, examples of combinations of these organic resin materials and incompatible materials include urethane acrylic UV-curable resins and alkyl (meth) acrylates, but the range of selection of incompatible materials is particularly narrow. There is a problem.
JP 2005-230947 A JP 2001-1119050 A JP 2001-191021 A JP 2006-116533 A

  As described above, various methods for forming irregularities on the surface of a resin film or the like have been known. However, there has been no technique capable of forming regular fine irregularities on a large-area resin film or the like.

  Therefore, the problem to be solved by the present invention is to provide a method for producing a surface-treated substrate having regular fine irregularities on the surface, which can be applied to a resin film having a large area. Another object of the present invention is to provide a solar cell substrate comprising the surface processed substrate.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, if a deposited layer is formed by self-organizing fine particles on the target resin film and regularly arranged in a close-packed manner, and the lowermost layer shape is mechanically transferred to the resin film surface, regular fine irregularities are formed. The present invention has been completed by finding that a processed substrate having a surface can be obtained.

  The method for producing a surface-treated substrate having a fine uneven surface according to the present invention includes a step of applying a fine particle dispersion on the surface of a resin film; a step of forming a fine particle deposition layer by drying the applied fine particle dispersion; A step of mechanically embedding part or all of the deposited layer in the resin film; and a step of forming a fine uneven shape on the surface of the resin film by removing the fine particle deposited layer.

  In the above method, it is preferable to embed part or all of the fine particle deposition layer in the resin film by hot pressing. This is because the unevenness of the fine particle deposition layer can be more accurately transferred to the resin film surface by embedding the fine particle deposition layer by applying pressure while softening the resin film surface. Moreover, it is preferable to remove the fine particle deposition layer by dissolving the fine particles. This is because fine particles can be removed more reliably and easily.

  The solar cell substrate of the present invention is characterized by comprising a surface-treated substrate manufactured by the above method. Since the surface-treated substrate according to the present invention has a surface on which regular fine irregularities are formed, the solar cell substrate of the present invention has characteristics according to the surface shape.

  The light emitting device member of the present invention has a surface processed substrate manufactured by the above method. The said light emitting device member can exhibit the effect according to the characteristic of the surface processing board | substrate of this invention similarly.

  According to the method of the present invention, a regular fine uneven shape in which large depressions and protrusions are suppressed can be accurately formed on the surface of a large area resin film or a continuously produced long resin film. it can. Therefore, the present invention is very useful industrially as a substrate that can be applied to a substrate such as a solar cell substrate, an antiglare layer of a display, a dish for cell culture, and a finely textured surface.

  The method for producing a surface-treated substrate having a fine uneven surface according to the present invention includes a step of applying a fine particle dispersion on the surface of a resin film; a step of forming a fine particle deposition layer by drying the applied fine particle dispersion; A step of mechanically embedding part or all of the deposited layer in the resin film; and a step of forming a fine uneven shape on the surface of the resin film by removing the fine particle deposited layer. Hereinafter, the present invention will be described with reference to the drawings in the order of implementation.

(1) Application process of fine particle dispersion In the present invention, first, a fine particle dispersion is applied to the surface of a resin film.

  The material constituting the resin film used in the present invention is not particularly limited, and examples thereof include polyester polymers, cellulose polymers, polycarbonate polymers, acrylic polymers, olefin polymers, amide polymers, styrene polymers, imide polymers, Sulfone polymers, polyether sulfone polymers, polyether ether ketone polymers, vinylidene chloride polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, and blends of two or more of these Can be mentioned. However, when the fine particles are removed by dissolution in a later step, it is necessary to select one that is not eroded by the solvent used for dissolving the fine particles. For example, when silica fine particles are removed by dissolution, an acidic solvent having high activity such as hydrofluoric acid is used. Therefore, it is necessary to select a resin having high chemical resistance such as a liquid crystal polymer. The liquid crystal polymer is also preferable from the viewpoint that the thermal expansion coefficient can be controlled. Moreover, when it is necessary to transmit light, such as when the surface-treated substrate of the present invention is used as a solar cell substrate, a transparent material is used.

  The material constituting the resin film is preferably a thermoplastic material. This is because, when the fine particle deposition layer is mechanically embedded in a later step, the surface can be easily embedded by softening the surface by appropriate heating. However, in the case of using a thermosetting resin, a resin film in a semi-cured state called a B stage may be used, and the following steps may be performed to cure after transferring a fine uneven shape to the surface. .

  The thickness of the resin film is not particularly limited, but it is necessary to have a thickness sufficient to embed the deposited layer in at least the subsequent process, and it is preferable that the thickness remains so as not to impair workability. In addition, future applications should be considered in determining the resin film thickness. For example, when the surface-treated substrate of the present invention is used as a printed wiring board, it may be appropriately determined from the value of the dielectric breakdown voltage and the volume resistivity defined by JIS C2318 in consideration of electrical characteristics. If gas permeability can be a problem, it can be appropriately determined according to the application from the oxygen permeation amount defined by JIS K7126B, the water vapor permeation amount defined by JIS K7129B, and the like. When the translucency of the resin material is required, the resin material can be appropriately determined in consideration of the light transmission characteristics of the material. In general, considering the workability such as strength and handleability, the thickness is about 10 to 500 μm. Furthermore, 20-300 micrometers is preferable and 30-200 micrometers is more preferable.

  If the resin film used by this invention has a commercially available thing, what is necessary is just to use it, and you may prepare it by a conventional method. The preparation method can be appropriately selected depending on the future use. For example, when there is a possibility of using a surface-treated substrate manufactured by the method of the present invention in an apparatus that requires high vacuum such as a sputtering apparatus or a CVD apparatus, melt extrusion is performed so that no solvent remains in the resin film. A thermoplastic resin film may be prepared by molding or the like.

  A resin film reinforced with a reinforcing material may be used. The reinforcing material is not particularly limited, and when transparency is required, a resin having higher heat resistance such as creep resistance or glass than transparent resin materials such as transparent polyimide or fluororesin, or glass can be used. . Also, semiconductor materials such as silicon wafers, iron, copper, aluminum, aluminum alloys, titanium, stainless steel, or fiber composite materials such as CFRP made of carbon fiber or FRP made of glass fiber in terms of light weight may be used. it can. Among these, titanium and stainless steel are preferable from the viewpoint of corrosion resistance and the like, and stainless steel is particularly preferable from the viewpoint of cost. For example, the stainless steel here refers to a special steel that is superior in corrosion resistance compared to ordinary carbon steel, and is generally made of chromium steel having a Cr content of about 12% or more. , Ti, Nb and the like. It can be classified into a martensite type, a ferrite type, an austenite type, and the like depending on the difference in content, and examples thereof include SUS304, SUS306, or SUS430.

  The resin film used in the present invention is preferably a flat film, but may be a curved film such as a tube as long as the fine particle deposition layer can be formed or the embedded fine particle deposition layer can be removed. .

  When using the surface-treated substrate of the present invention as a constituent material of a device, when receiving a thermal history, in order to prevent delamination and warping, the thermal expansion coefficient of both is close as the material of the resin film and the reinforcing material Is preferably selected. From this point of view, the resin film and the reinforcing material may be the same. Or after processing the surface of a resin film using a stainless plate etc. as a reinforcement, you may peel and use the said resin film from a reinforcement.

  The kind of fine particles used in the method of the present invention is not particularly limited, and for example, inorganic fine particles such as metal fine particles and metal oxide fine particles; or resin fine particles can be used. Particularly, colloidal silica fine particles are suitable from the viewpoint of cost and heat resistance. The fine particles need not be a single substance, and may be a mixture of two or more kinds.

  The role of the fine particles in the present invention is to form a dense deposited layer and transfer the shape of the lowermost layer to a resin film. Therefore, in order to produce a surface-treated substrate having a fine uneven shape on the surface, the 50% cumulative diameter of the fine particles is preferably in the range of 0.01 to 10 μm, and more preferably in the range of 0.1 to 1 μm. Further, in order to increase the degree of filling of the fine particles in the deposited layer, the shape of the fine particles is preferably as spherical as possible, and the particle size distribution range is preferably as narrow as possible. The 50% cumulative diameter refers to the particle diameter when the cumulative volume is 50% from the smallest particle when the particle size distribution is measured by a particle size distribution meter. The 50% cumulative diameter may refer to the catalog value of the fine particles used, or may be measured by a conventional method.

  In some cases, the particle diameter may be increased by a sol-gel method, a plating method, a mechanochemical method in which particles are kneaded with a resin under a high shear force and the surface is coated with the resin. Further, fine particles that do not interfere with the multilayer structure formed by the fine particles having the main particle size may be mixed.

  The solvent for the fine particle dispersion is not particularly limited, and an aqueous solvent or an organic solvent solvent can be used, but use of a resin film or a solvent that dissolves the fine particles must be avoided. Further, a surfactant may be used to improve wettability with the resin film and fine particle dispersibility. However, when the processing temperature of the resin is equal to or higher than the thermal decomposition temperature of the surfactant, it is preferable to remove the surfactant in advance by a treatment such as chemical or thermal decomposition after the fine particle deposition layer is formed.

  The concentration of the fine particles in the fine particle dispersion is not particularly limited, but if the concentration is too low, it may take time to dry, and a highly regular fine particle deposition layer may not be formed. On the other hand, if the concentration is too high, the dispersion state of the dispersion may not be maintained. Therefore, it is usually about 10 to 40 wt%.

  Conventional means may be used as means for applying the fine particle dispersion to the surface of the resin film. For example, spraying, dipping, spin coating, roll coating, gravure coating, bar coating, screen printing, flexographic printing, and the like can be used.

(2) Formation process of fine particle deposition layer Next, the fine particle dispersion layer applied to the surface of the resin film is dried to form the fine particle deposition layer (see FIG. 1). Specifically, the solvent contained in the fine particle dispersion is gradually distilled off by drying. Along with that, the fine particles accumulate and form a so-called self-assembled film. In such a self-assembled film, since the fine particles are deposited in a close-packed manner, the arrangement of the fine particles is very regular.

  In addition, it is also conceivable that the fine particle dispersion liquid is not simply dried, but a fine particle deposition layer having a regular arrangement is easily formed by self-organizing the particles by a method called an advection accumulation method. The advection accumulation method is a method in which the coated fine particle dispersion is not dried over the entire surface but gradually dried from the end of the coated surface. As a result, the fine particle concentration at the dry end increases, and the self-organization of the fine particles gradually proceeds from the end, so that a dense fine particle deposition layer having a regular arrangement can be easily obtained.

  Suitable drying conditions vary depending on the solvent of the fine particle dispersion, the drying method, and the like, and may be adjusted as appropriate. For example, in the case of the advection accumulation method, nitrogen gas or filtered compressed air may be blown from the end portion at room temperature, and the drying time can be appropriately adjusted depending on the thickness of the fine particle accumulation layer. When simply drying, the drying conditions are adjusted mainly by the solvent of the fine particle dispersion. For example, when a fine particle dispersion using water as a solvent is spin-coated, it can be naturally dried at room temperature, but when a solvent having a high boiling point is used, it may be dried at a high temperature of about 100 to 200 ° C. .

  Conventionally, a method of forming a single particle film instead of the above-described deposited layer has been studied, but it is not preferable because it is complicated and difficult industrially. On the other hand, in the method of the present invention, since the shape of the lowest layer of the fine particle deposition layer that can be easily formed is transferred to the resin film, it is not necessary to form a single particle film. Further, the thickness of the fine particle deposition layer is not particularly limited. For example, the amount and concentration of the fine particle dispersion to be used may be determined in consideration of prevention of cracks and removal of fine particles.

  When a surfactant is added to the fine particle dispersion, the solvent may be further heated after the solvent of the fine particle dispersion is distilled off to form the fine particle deposition layer in order to remove the surfactant. This heating condition can be appropriately adjusted according to the type of surfactant. However, since the resin film may be affected if the temperature is too high, the type of the resin film should be considered.

(3) Step of Embedding Fine Particle Deposition Layer Next, part or all of the fine particle deposition layer formed on the resin film is mechanically embedded in the resin film (see FIG. 1). Here, in a method in which the resin is completely melted without using a mechanical method and the fine particle deposition layer is embedded in the resin film, there is a possibility that defects such as surface tension such as meniscus scooping may occur.

  In the present invention, a part or all of the fine particle deposition layer is embedded in the resin film, but there is no restriction that the fine particles to be embedded are only the lowermost layer. However, when the thickness of the fine particle accumulation layer exceeds the thickness of the resin film, it is necessary to adjust the pressure so that the resin film is not damaged by embedding. Preferably, the thickness of the particulate deposition layer is less than the thickness of the resin film, and the entire particulate deposition layer is embedded in the resin film. Embedding all is efficient without the need for delicate adjustment of pressure conditions.

  As a method for embedding the fine particle accumulation layer, in the case of a thermoplastic resin, a method in which the fine particle accumulation layer is pushed in by a flat plate press, a roll press or the like in a temperature range where the compression strength of the fine particles is higher than the compression strength of the resin can be considered. In general, the embedding temperature is equal to or higher than the softening point specified in JIS K7196, which describes the softening temperature test method by thermomechanical analysis of thermoplastic films and sheets, and the processing temperature can relieve stress. Any condition is acceptable. In the present invention, since the fine particle deposition layer is mechanically embedded, even if the resin film surface is completely melted, unevenness of the resin layer thickness and abnormal protrusion due to surface tension are unlikely to occur. When a B-stage thermosetting resin is used as the resin film material, pressure may be applied without particularly controlling the temperature.

(4) Step of forming uneven shape Next, a fine uneven shape is formed on the surface of the resin film by removing the fine particle deposition layer embedded in the resin film (see FIG. 1). That is, since the shape of the lowermost layer of the fine particle deposition layer in which the fine particles are regularly arranged is transferred on the surface of the resin film, the fine irregular surface shape can be obtained regularly by removing the fine particles.

  The means for removing the particulate deposit layer embedded in the resin film is not particularly limited, and may be a mechanical method. However, since fine particles may remain in the mechanical method, the fine particles are preferably removed by dissolution. The solvent used for such dissolution can be appropriately determined depending on the material of the fine particles. For example, sulfuric acid or alkali is used for titanium dioxide, and hydrofluoric acid or a mixed solution of hydrofluoric acid and nitric acid, alkali, or the like is applicable for silicon dioxide. As for organic materials, polymethyl methacrylate is soluble in acetone, ethyl acetate, toluene and the like, and polystyrene and the like are soluble in toluene and xylene.

  When the fine particle accumulation layer is removed by dissolution, a porous layer can be formed on the surface of the resin film (see FIG. 1). Such a porous layer can also be used as a functional layer, but it is necessary to remove all of the porous layer when irregularities are formed on the substrate surface. At this time, since the porous layer is obtained as a shape after removing the self-assembled film of particles, there is no need for a particularly accurate peeling method when physically peeling, and the relationship of film strength Moreover, it can be easily peeled off from the interface between the porous layer and the solid layer. Moreover, since the uneven part formed on the substrate surface is sufficiently higher than the strength of the porous layer, the uneven part is left as it is.

  The method for removing the porous layer is not particularly limited as long as the strength at the time of peeling can be controlled so as not to damage the unevenness formed on the surface of the substrate. For example, it can be peeled off by polishing, chemical mechanical polishing, sand blasting, dry ice blasting, ultrasonic cleaning, high pressure water pressure cleaning, or a combination thereof.

  At this time, since the porous layer is obtained as a shape after removing the self-assembled film of particles, there is no need for a particularly accurate peeling method when physically peeling, and the relationship of film strength Moreover, it can be easily peeled off from the interface between the porous layer and the solid layer. Moreover, since the uneven part formed on the substrate surface is sufficiently higher than the strength of the porous layer, the uneven part is left as it is.

  In addition, when the fine particle deposition layer is removed by a mechanical method without dissolving the fine particles in the step of removing the fine particle accumulation layer, an excessive residual portion of the resin film is also removed together with the fine particle accumulation layer. It becomes possible to obtain. That is, the removal process of the particulate deposition layer and the removal process of the porous layer can be performed simultaneously by a mechanical method. However, as described above, since the fine particles may not be completely removed only by the mechanical method, the fine particle accumulation layer may be dissolved and removed, and then the obtained porous layer may be removed by the mechanical method. preferable.

  The surface-treated substrate obtained by the method of the present invention has a regular and fine uneven surface. Therefore, since the occurrence of local holes and steep protrusions is suppressed, for example, when the surface processed substrate according to the present invention is applied to a solar cell, other layers such as a back electrode, a transparent electrode, a silicon layer, etc. are applied onto the substrate. It is possible to suppress breakage or short circuit of these layers when forming the film. In addition, the light diffusion intensity can be improved, and the optical path length inside the silicon layer is increased, so that the energy conversion efficiency can be improved. In order to make this action and effect even more reliable, annealing that has occurred for a certain period of time near the heat distortion temperature where the formed irregularities do not collapse can be relaxed. Further, the quality of the substrate can be further stabilized.

  The surface-treated substrate of the present invention can be used as a solar cell substrate. Specifically, for example, a back electrode (reflection layer), an n-type silicon layer, an i-type silicon layer, a P-type silicon layer, a transparent electrode layer, and a collecting electrode are sequentially formed on a liquid crystal polymer substrate surface-treated according to the present invention. By doing, it can be set as a thin film solar cell. Further, when a substrate made of a resin having transparency such as polycarbonate, PEN, or PET is subjected to surface processing according to the present invention, a thin film solar cell can be formed by constructing the above solar cell structure in reverse.

  Since the surface-treated substrate of the present invention has a fine concavo-convex surface, sunlight can be diffused internally, and sunlight can be used efficiently. On the other hand, since the surface processed substrate of the present invention has few local holes and steep protrusions, the electrode and silicon layer formed on the substrate are less likely to be damaged, such as the yield and fill factor of solar cell devices. The solar cell performance is improved, and as a result, it can contribute to the improvement of energy conversion efficiency.

  The surface-treated substrate of the present invention can also be used as a light emitting device member. This is because the surface-treated substrate of the present invention has a regular and fine concavo-convex shape and excellent optical characteristics. Specifically, it can be used as a display device member such as an antireflection film, a diffuse reflector, or a prism sheet.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. It is also possible to implement, and they are all included in the technical scope of the present invention.

Production Example 1
A 125 μm-thick liquid crystal polymer film (trade name “BIAC”, manufactured by Japan Gore-Tex Co., Ltd.) was cut into a 5 cm square. A SUS foil having a thickness of 150 μm and a side of 5 cm was laminated on the liquid crystal polymer film, and was pressed using a press machine at a temperature of 290 ° C. and a pressure of 40 kg / cm ² to prepare a resin layer / heat-resistant reinforcing material substrate. . Separately, 50 g of colloidal silica aqueous dispersion (manufactured by Nissan Chemical Industries, MP4540-M) containing silica fine particles having a 50% cumulative diameter of 0.45 μm and 0.2 g of a surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Epan 785) Were mixed to prepare a coating solution.

The coating solution was applied to the substrate at 500 rpm for 30 seconds using a spin coating apparatus. When the amount of solid content applied after drying was measured with an electromagnetic balance (A-D, GR-300), it was about 2 g / m ² . Furthermore, in order to remove surfactant, it heated at 230 degreeC for 30 minute (s).

Next, the formed silica fine particle deposition layer was embedded in the resin layer by pressurizing using a press machine under conditions of a temperature of 290 ° C. and a pressure of 40 kg / cm ² . Thereafter, the silica fine particle deposition layer was dissolved and removed by dipping in 46% hydrofluoric acid for 1 minute. It was washed and dried sufficiently, and further washed with an ultrasonic cleaner to obtain a resin layer having a fine uneven surface. The uneven surface was observed with a scanning electron microscope. The photograph is shown in FIG. According to FIG. 2, it can be confirmed that the surface-treated substrate obtained by the method of the present invention has regularly fine uneven surfaces without large depressions or protrusions.

Production Example 2
A 125 μm-thick polycarbonate film (manufactured by Teijin Chemicals Ltd., Panlite sheet) was cut into a square with a side of 5 cm. A SUS foil having a thickness of 150 μm and a side of 5 cm was laminated on the liquid crystal polymer film, and was pressed using a press machine at a temperature of 290 ° C. and a pressure of 40 kg / cm ² to prepare a resin layer / heat-resistant reinforcing material substrate. . Separately, 50 g of an aqueous colloidal silica dispersion (manufactured by Nissan Chemical Co., Ltd., MP4540-M) used in Production Example 1 and 0.2 g of a surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Epan 785) are mixed and coated. A liquid was prepared.

The coating solution was applied to the substrate at 500 rpm for 30 seconds using a spin coating apparatus. When the amount of solids applied after drying was measured in the same manner as in Production Example 1, it was about 2 g / m ² . Furthermore, in order to remove surfactant, it heated at 230 degreeC for 30 minute (s).

Next, the formed silica fine particle deposition layer was embedded in the resin layer by pressurizing using a press machine under conditions of a temperature of 290 ° C. and a pressure of 40 kg / cm ² . Thereafter, the silica fine particle deposition layer was dissolved and removed by dipping in 46% hydrofluoric acid for 1 minute. It was washed and dried sufficiently, and further washed with an ultrasonic cleaner to obtain a resin layer having a fine uneven surface. When the uneven surface was observed with a scanning electron microscope, it was confirmed that the uneven surface was a regular uneven surface without large depressions or protrusions.

It is a schematic diagram which shows one aspect | mode of this invention method. It is a 20,000 times micrograph of the surface processing board | substrate which has the fine uneven surface obtained by the method of this invention.

Explanation of symbols

  1: fine particle accumulation layer, 2: resin film, 3: reinforcing material, 4: porous layer, 5: regular fine uneven surface

Claims (5)

A method for producing a surface-treated substrate having a fine uneven surface,
Applying a fine particle dispersion on the surface of the resin film;
Forming a particulate deposit layer by drying the applied particulate dispersion;
A step of mechanically embedding part or all of the fine particle deposition layer in the resin film; and a step of forming a fine uneven shape on the surface of the resin film by removing the fine particle deposition layer;
The manufacturing method characterized by including.   The manufacturing method according to claim 1, wherein a part or all of the fine particle deposition layer is embedded in the resin film by hot pressing.   The production method according to claim 1 or 2, wherein the removal of the fine particle deposition layer is performed by dissolving the fine particles. A solar cell substrate comprising a surface-treated substrate manufactured by the method according to any one of claims 1 to 3, wherein a 50% cumulative diameter is 0.01 to 10 µm of spherical fine particles of a close-packed stacked layer. A solar cell substrate, wherein the lowermost layer shape is transferred to the surface . A light-emitting device member having a surface-treated substrate manufactured by the method according to any one of claims 1 to 3, wherein a 50% cumulative diameter of 0.01 to 10 µm of spherical fine particles close-packed deposition layer A light emitting device member characterized in that a lowermost layer shape is transferred to a surface .