JP2019012186A - Manufacturing method of article with concave or convex portion - Google Patents

Abstract

To provide a manufacturing method of an article with a surface containing at least one concave portion, and a manufacturing method of an article with a surface containing at least one convex portion.SOLUTION: A manufacturing method of a first article with a surface containing at least one concave portion, includes the steps of: providing a curable fluid 330 on at least one part of a surface of a molding die 310; introducing at least one air bubble 350 between the surface of the molding die 310 and the curable fluid 330; altering an angle formed between a tangent line of the air bubble 350 and the surface of the molding die 310 by applying a potential difference between at least a part of the molding die 310 and the curable fluid 330; and forming at least one concave portion in the curable fluid 330 by using the air bubble 350 as at least one part of a molding surface. A second article containing at least one convex portion is manufactured by utilizing the first article as the molding die 310.SELECTED DRAWING: Figure 3C

Description

The present invention relates to a method for manufacturing an article having at least one recess or protrusion.

  Articles having components with concave or convex surfaces, or articles having many concave or convex surfaces arranged thereon, can be used in various industrial fields such as abrasive members, O-rings, and the like. On the other hand, in some applications, the concave or convex surface can function as a lens. For example, a sheet-like article having a number of concave or convex surfaces arranged thereon can function as an array of lenses, such as an array of microlenses (ie, a microlens array). In recent years, such a sheet-like article that can be used as a microlens array has attracted much attention. Microlens arrays may be suitable for various optical applications such as displays, light extraction films for organic light emitting devices, semiconductor lasers, and optical fibers.

  Japanese translations of PCT publication No. 2011-503660 describes a method of manufacturing an article having at least one recess using a molding surface containing at least one bubble. In this manufacturing method, a smooth concave surface that is a reversal of a part of the smooth convex surface of the bubbles can be imparted to the article.

  When a voltage is applied between the conductive liquid and the electrode, the energy at the solid-liquid interface between the electrode surface and the liquid changes, and the display device uses an electrowetting phenomenon in which the shape of the liquid surface changes. Liquid lenses are known and are described in JP-A-2014-240875 and the like.

  Chinese Patent No. 103149607 and Non-Patent Document 1 describe a method of manufacturing a microlens array using a mold having an electrically induced shape.

International Publication No. 2009/67308 JP 2014-240875 A Chinese Patent No. 103149607

X.M.Li, Y.C.Ding, J.Y.Shao, H.M.Tian, H.Z.Liu, Advanced Optical Materials 2012, 24, OP165-OP169

  In a method of manufacturing an article having at least one recess using a molding surface containing at least one bubble, the curable fluid is provided between the mold and the curable fluid in providing the curable fluid to the surface of the mold. A bubble is entrained, and the shape of the bubble is used to form a recess. The shape of the bubble is determined by the surface shape of the mold and the contact angle between the mold surface and the curable fluid determined by the material constituting them. It was decided by. That is, in order to change the bubble shape and the radius of curvature, it is necessary to change the shape of the mold and the material used. There is a demand for a method of changing the shape and curvature radius of bubbles more easily without changing the shape and material of the mold.

  The present invention relates to a method for manufacturing an article having at least one recess or protrusion. More specifically, an article having a surface that includes at least one recess is manufactured using a molding surface that changes the shape of at least one cell by applying a potential difference and includes the cell. This article having at least one recess is subsequently used as a mold for forming a second article having at least one protrusion.

  One embodiment of the present invention is a method of manufacturing an article having a surface that includes at least one recess. The method includes providing a curable fluid over at least a portion of the mold surface, introducing at least one bubble between the mold surface and the curable fluid, a portion of the mold. And changing the angle α between the tangent of the bubble and the surface of the mold by applying a potential difference between the curable fluid and the curable fluid, and using the bubbles as at least a part of the molding surface, Including providing individual recesses.

  One embodiment of the method further comprises the step of providing an article having a surface comprising at least one recess, wherein the conductive film is disposed in contact with the curable fluid on a surface where the curable fluid does not contact the mold. Is the method.

  Another embodiment of the method is that applying a potential difference between at least a portion of the surface of the mold and the curable fluid provides a potential difference between the conductive film and the mold after the surface of the mold. A method of manufacturing an article having a surface including at least one recess comprising providing a curable fluid.

  Another embodiment of the method is a method of manufacturing an article having a surface that includes at least one recess, further comprising curing the curable fluid after providing the curable fluid with at least one recess. .

  Another embodiment of the method is that applying a potential difference between at least a portion of the mold surface and the curable fluid results in a plurality of potential differences depending on location between the mold surface and the curable fluid. A method of manufacturing an article having a surface including at least one recess.

  Another embodiment of the method is a method of manufacturing an article having a surface that includes at least one recess that reduces the angle α by applying a potential difference.

  One embodiment of the present invention is a method for manufacturing a second article having a surface including at least one convex portion. The method includes applying at least one protrusion to the surface of the second article using an article having at least one recess as a mold for the second article. In some embodiments of the method, the first article used as the mold for the second article has an array pattern of recesses, and the second article has an array pattern of protrusions.

  According to the present invention, the shape and the radius of curvature of the bubble can be changed more easily without changing the shape and material of the molding die, and the shape of the recess formed using the bubble shape can also be changed. .

Schematic diagram of the angle α between the bubble tangent and the mold surface Principle diagram explaining electrowetting phenomenon Principle diagram explaining electrowetting phenomenon Schematic cross-sectional view illustrating an embodiment of a method for manufacturing a first article having at least one recess. Schematic cross-sectional view illustrating an embodiment of a method for manufacturing a first article having at least one recess. Schematic cross-sectional view illustrating an embodiment of a method for manufacturing a first article having at least one recess. Schematic cross-sectional view illustrating an embodiment of a method for manufacturing a first article having at least one recess. Schematic cross-sectional view illustrating an embodiment of a method for manufacturing a first article having at least one recess. The schematic sectional drawing which illustrates one Embodiment of the manufacturing method of the 2nd article | item which has at least 1 convex part. The schematic sectional drawing which illustrates one Embodiment of the manufacturing method of the 2nd article | item which has at least 1 convex part. The schematic sectional drawing which illustrates one Embodiment of the manufacturing method of the 2nd article | item which has at least 1 convex part. Schematic illustrating one embodiment of a mold having a plurality of depressions Schematic illustrating another embodiment of a mold having a plurality of depressions Photo of the conductive mold used in the examples Electron micrograph showing an example of a second article having a plurality of convex portions arranged in a lattice pattern Electron micrograph showing an example of a second article having a plurality of convex portions arranged in a lattice pattern Electron micrograph showing an example of a second article having a plurality of convex portions arranged in a lattice pattern Electron micrograph showing an example of a second article having a plurality of convex portions arranged in a lattice pattern Optical micrograph of cut surface of an example of second article Optical micrograph of cut surface of an example of second article

  Hereinafter, representative embodiments of the present invention will be described in more detail for the purpose of illustration, but the present invention is not limited to these embodiments. That is, the description of the present disclosure should not be construed as disclosing all embodiments of the present invention and all advantages related to the present invention.

  A method of manufacturing an article having at least one recess or at least one protrusion is provided. At least one recess or protrusion of the article can be used, for example, as a lens or as an array of lenses. In some embodiments, at least one recess of the article can be used as a microlens or an array of microlenses (ie, a microlens array). As used herein, the term “microlens” refers to a lens whose dimensions, such as diameter, are in the range of about 0.1 micrometers to about 1000 micrometers. The microlens corresponds to a minute convex portion or a minute concave portion on the surface of the article. As used herein, the terms “micro-recess” and “micro-protrusion” refer to a recess or protrusion that has a diameter in the range of about 0.1 micrometers to about 1000 micrometers, respectively. As used herein, the term “diameter” corresponds to the maximum cross-sectional dimension when referring to a recess or protrusion.

  In accordance with one aspect of the present invention, an article having a surface that includes at least one recess can be produced. During manufacture, at least one bubble is intentionally introduced to provide at least one recess in the surface of the article. That is, the article (a) provides a curable fluid over at least a portion of the mold surface, and (b) introduces at least one bubble between the mold surface and the curable fluid. (C) changing the angle α between the tangent of the bubble and the surface of the mold by applying a potential difference between at least a part of the surface of the mold and the curable fluid; (d) the outer surface of the bubble Forming a article from a curable fluid using a molding surface comprising at least a portion of

  In accordance with another aspect of the invention, a plurality of recesses, such as an array pattern of recesses, are formed on the surface of an article using a molding surface that includes a plurality of bubbles positioned at different locations on the molding surface. That is, an article having an array pattern of recesses (a) providing a curable fluid on at least a portion of the mold surface, and (b) a plurality of bubbles between the mold surface and the curable fluid. (C) changing the angle α between the tangents of the plurality of bubbles and the surface of the mold by applying a potential difference between at least a part of the surface of the mold and the curable fluid; d) using a molding surface that includes at least a portion of the outer surface of the cell to form an article from the curable fluid.

  As used herein, “at least one recess” refers to a single concave surface or a plurality of concave surfaces. A single or multiple concave surfaces are imparted to an article using a single bubble introduced at a single location on the mold surface, or using multiple bubbles introduced at multiple locations on the mold surface be able to. Multiple recesses can be positioned or arranged at random locations or arbitrary locations, or arranged in a pattern on the surface of the article.

  “Intentional introduction” means introducing them for the purpose of using bubbles as a substantial tool in the manufacturing process of the article. That is, the bubbles are part of the molding surface that is used to impart at least one recess to the article surface. In some embodiments, intentional introduction means not removing or enclosing any air bubbles that may already be present. For example, deliberate introduction means not removing any air bubbles that may be located in one or more recesses of the mold while providing a curable fluid to a portion of the mold. Can mean. That is, deliberate introduction can mean enclosing air bubbles in the mold cavity prior to providing the curable fluid to a portion of the mold. The enclosed bubbles are part of the molding surface that comes into contact with the curable fluid.

  In some embodiments, an article having a surface that includes an array pattern of recesses can be produced. During manufacture, bubbles are provided at a plurality of locations to impart an array of recesses on the surface of the article. More specifically, an article is manufactured using a molding surface that includes a plurality of bubbles arranged in a pattern corresponding to the pattern of recesses imparted to the article. An article having an array pattern of recesses can be easily manufactured.

  A “recess arrangement pattern” is a pattern of a plurality of depressions arranged at a given position, arranged with a certain degree of regularity, or arranged in any desired manner. For example, the array pattern of the recesses may include an array pattern arranged such as an array pattern, an array of square lattice patterns, an array of zigzag patterns, or an array of radiation patterns. The arrangement pattern of the recesses does not need to be uniformly formed on the entire article, and may be formed only on a part of the article. The pattern of the recesses may or may not change over any part of the article. For example, similar or different patterns can be used in the same plane. The plurality of recesses in the pattern can be the same size and shape, or can have different sizes and shapes.

  Any suitable gas can be used to form a bubble that imparts a recess to the surface of the article. For example, the gas can be air or an inert gas such as nitrogen and argon.

  As shown in FIG. 1, “bubble tangent” 170 is in contact with the surface 112 of the mold 110, where the angle between the bubble tangent 170 and the mold surface 112 (the angle inside the curable fluid 130). Is the “angle α”. The angle α1 when a potential difference is given between a part of the mold and the curable fluid is different from the angle α0 when no potential difference is given. When α1 is smaller than α0, the surface of the mold is made of a water-repellent material, and the angle α0 is set large to increase the difference between α1 and α0.

  Although not wishing to be bound by any theory, as an electrowetting phenomenon, when a voltage is applied between the liquid and the electrode, the energy at the solid-liquid interface between the electrode surface and the liquid changes, and the liquid A phenomenon in which the shape of the surface changes is known. FIG. 2A and FIG. 2B are diagrams showing a principle diagram for explaining the electrowetting phenomenon. A dielectric layer 203 is formed on the electrode 202, and a droplet 204 is placed thereon.

  As shown in FIG. 2A, in the state where no potential difference is given, the interface energy γSL between the surface of the dielectric layer 203 and the droplet 204 is large, so the contact angle θ0 is large. Here, the contact angle θ 0 is an angle between the surface of the dielectric layer 203 and the tangent line of the droplet 204, and depends on properties such as the surface tension of the droplet 204 and the surface energy of the dielectric layer 203. On the other hand, when a voltage is applied between the electrode 202 and the needle-like electrode inserted into the droplet 204, the electrolyte ions on the droplet 204 side concentrate on the surface of the dielectric layer 203 as shown in FIG. The charge amount of the multilayer is changed, and the surface tension of the droplet 204 is changed. As a result, the contact angle θ decreases. The contact angle θ at this time is expressed by the following equation of Lippmann-Young.

  Here, θ0 is the contact angle when no voltage is applied, εr is the dielectric constant of the dielectric layer, ε0 is the vacuum dielectric constant, t is the thickness of the dielectric layer, and γLG is the surface tension of the droplet. , V is an applied voltage. As a function of the voltage V, the contact angle θ changes the surface shape (curvature) of the droplet 204 depending on the magnitude of the applied voltage V between the electrode 202 and the droplet 204.

  The molding surface used to form the article in the present invention includes a portion of the outer surface of at least one cell. The outline of the bubbles contained in the molding surface that is in contact with the curable fluid can be anti-transferred to the article. Since various shapes and sizes of bubbles having a diameter in the range of several nanometers to several centimeters or more can be included in the molding surface, it is possible to form a plurality of recesses having a wide range of shapes and sizes. Furthermore, when a plurality of recesses are formed in an article, the size and shape of the plurality of recesses may be the same or different. That is, the molding surface can include a plurality of bubbles that are different in size and shape, or that have the same size and shape.

  This method can be used to form a single recess on the surface of the article or multiple recesses on the surface of the article. Once a plurality of recesses are formed, the plurality of recesses can be positioned on the surface of the article in any manner. In some examples where multiple recesses are formed, the multiple recesses are arranged in a pattern.

  One embodiment of an article having a surface that includes at least one recess can be manufactured according to the following process: (a) providing a mold having a mold surface, and a conductive film, (b) a mold. (C) providing a curable fluid between at least a part of the surface of the mold and the conductive film, and (d) providing a surface of the mold and curing. Deliberately introducing at least one bubble with the functional fluid, and (e) curing the curable fluid to form an article having at least one recess imparted by the bubbles on the surface. . By providing a potential difference between at least a part of the mold and the conductive film, a potential difference was applied between at least a part of the surface of the mold and the curable fluid, and the curable fluid was provided to the surface of the mold. Sometimes the shape of the bubble introduced can be changed.

  An article having a surface containing an array pattern of recesses can be manufactured according to the following process: (a) providing a mold having a mold surface arranged in a pattern, and a conductive film, (b) molding Providing a potential difference between at least a portion of the mold and the conductive film; (c) providing a curable fluid between at least a portion of the mold surface and the conductive film; and (d) selecting based on the array pattern. Providing bubbles at a plurality and distinct locations between the formed mold surface and the curable fluid; and (e) curing to form an article having an array pattern of recesses imparted by the bubbles on the surface. Curing the sexual fluid. The article is typically removed from the mold.

  The “conductive film” is disposed so that the curable fluid is in contact with the curable fluid on the surface where the curable fluid is not in contact with the mold. As the conductive film, a resin film provided with a conductor layer may be used. There is no restriction | limiting in particular as a resin film, About the material, a shape, a structure, etc., it can select suitably from well-known things. For example, polyester resin films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), modified polyester; polyolefin resin films such as polyethylene (PE) resin film, polypropylene (PP) resin, cyclic olefin resin; polyvinyl chloride, Vinyl resin film such as polyvinylidene chloride; polystyrene resin film; polyetheretherketone (PEEK) resin film; polysulfone (PSF) resin film; polyethersulfone (PES) resin film; polycarbonate (PC) resin film; polyamide resin film Polyimide resin film; acrylic resin film; triacetyl cellulose (TAC) resin film and the like. When the curable fluid is cured by light, a resin film that transmits the wavelength of the light can be used. The thickness of the resin film may be 5 μm to 2000 μm.

  As the conductor layer provided on the surface of the resin film, indium tin oxide (ITO), a metal vapor deposition film, or the like can be used. When the curable fluid is cured by light, a conductor layer that transmits the wavelength of the light may be used. By providing a conductive layer having a network structure (lattice shape, turtle shape, etc.), light may be transmitted from a region where no conductive layer exists. The thickness of the conductor layer may be 0.01 μm to 1000 μm. The conductive film is disposed so that the conductor layer is in contact with the curable fluid.

  By applying a potential difference between at least a part of the mold and the conductive film, a potential difference can be applied between at least a part of the mold and the curable fluid. In this case, a potential difference may be applied between the mold and the conductive film after providing the curable fluid between the conductive film and the mold. In order to align the shape of the plurality of bubbles, a potential difference may be applied between the mold and the conductive film before providing the curable fluid.

  Furthermore, the shape of the bubble introduced between each conductive film and a shaping | molding die can also be changed by preparing several conductive films and applying a different voltage to each.

  The “mold surface” is the actual surface of the mold. When bubbles are introduced between the mold surface and the curable fluid, the curable fluid is in direct contact with the actual surface of the mold in at least one location and in direct contact with the bubbles in at least one other location. doing. The combination of the actual surface of the mold and at least the cell surface provides the molding surface. That is, as used herein, the term “molding surface” refers to a surface that is in direct contact with the curable fluid. The shape of the molding surface (specifically, the inverted shape of the molding surface) can be imparted to the surface of the article formed when the curable fluid is cured. The recesses on the surface of the article correspond to locations where the curable fluid is in contact with the bubbles during the curing process. Thus, the shape and dimensions of the bubble portions in contact with the curable fluid can be imparted to the cured article to provide one or more recesses.

  As the mold, a conductive mold having conductivity such as metal, or a dielectric mold having a dielectric layer provided on the surface of the conductive mold can be used. Any suitable conductive material can be used as the material for the conductive mold. Some representative materials for the conductive mold include copper, nickel-plated copper, tin, zinc, iron, chromium, titanium, aluminum alloys and the like.

  The mold can be of any suitable dimensions, but the dimensions are often selected based on the dimensions of the coating equipment. Some exemplary molds have a longitudinal dimension in the range of 1 to several thousand millimeters, a lateral dimension in the range of 1 to several thousand millimeters, and a thickness dimension in the range of 10 micrometers to greater than 10 millimeters.

  Before providing the dielectric layer on the surface of the conductive mold, argon gas, oxygen or the like is used for the purpose of cleaning the surface of the conductive mold or for improving the adhesion between the dielectric layer and the conductive mold. The conductive mold may be plasma treated.

  A water repellent layer may be provided on the surface of the dielectric layer. Examples of the material for the water repellent layer include trimexisilane and octafluoropropane.

  The dielectric mold may be composed of one or more pieces. For example, a mold having a plurality of pieces can be composed of a first layer having at least one opening, and a second layer laminated on the first layer.

  The dielectric mold typically has a depression. These depressions can correspond to the opening or pattern of openings in the first layer of the dielectric mold having a plurality of pieces, or can be part of a mold that is a single piece. The depression is often used to provide at least one bubble that is part of the molding surface. For example, at least one bubble can be encapsulated in the recess as the curable fluid is provided to a portion of the mold surface.

  If a mold cavity is used to enclose at least one bubble, an article having a surface that includes at least one recess can be manufactured according to the following process: (a) a mold surface with a cavity Providing a mold having (b) providing a curable fluid over at least a portion of the mold surface, and (c) enclosing air bubbles in a recess between the mold surface and the curable fluid. (D) changing the angle α between the tangent of the bubble and the surface of the mold by applying a potential difference between at least a part of the surface of the mold and the curable fluid, and (e) Curing the curable fluid to form an article having a recess imparted by air bubbles in the recess. The article is typically removed from the mold.

  If the mold has a plurality of depressions that can be used to enclose the bubbles, the depressions can be arranged in a pattern. Articles having an array pattern of recesses can be manufactured according to the following process: (a) providing a mold having a mold surface with a plurality of depressions arranged in a pattern; (b) a mold surface Providing a curable fluid over at least a portion of the mold, (c) enclosing a plurality of bubbles in the plurality of recesses between the mold surface and the curable fluid, and (d) at least one of the mold surfaces. Changing the angle α formed between the tangent of the bubble and the surface of the mold by applying a potential difference between the portion and the curable fluid, and (e) the recess provided by the bubbles in the plurality of depressions on the surface Curing the curable fluid to form an article having an array pattern of: The article is typically removed from the mold.

  A “curable fluid” is a fluid that has sufficient fluidity to provide to the mold and can be cured regardless of the curing method. Suitable curable fluids include, for example, gel, paste, or liquid organic materials, inorganic materials, or organic-inorganic composite materials. Other suitable curable fluids include solutions, dispersions, suspensions, etc. obtained by diluting organic materials, inorganic materials, or organic-inorganic composite materials with suitable solvents (ie, organic solvents or aqueous solutions). System solvent). The curable fluid may be adjusted to an optimal viscosity to confine bubbles. For example, the viscosity is 4,000 to 15,000 cps.

  As used herein, “curing” refers to the process of making a curable fluid hard enough to retain the shape imparted by the molding surface. More specifically, the curable fluid becomes hard enough to retain the shape imparted by at least one bubble that is part of the molding surface, and the resulting “cured layer” has at least 1 Has two recesses. The cured layer is a product formed when the curable fluid is cured.

  When the organic material is included in the curable fluid, a resin material or a precursor of the resin material can be used. The curable fluid can include, for example, a monomer or polymer that polymerizes, cures, or crosslinks upon curing. As the “curing method”, any suitable method including, but not limited to, polymerization of a polymerizable resin, cooling of a thermoplastic resin to at least a softening temperature, or drying of a solvent is used. it can. Typical resin materials include reactive resins such as photocurable resins that can be cured by polymerization when irradiated with radiation (for example, ultraviolet rays, visible rays, or electron beams), and thermosetting properties that are cured by thermal alignment polymerization. Examples thereof include, but are not limited to, resins, reactive resins that can be cured by oxidative orientation polymerization, reactive resins that can be cured by reductive orientation polymerization, or thermoplastic resins that can be cured at least when cooled to the softening temperature.

  In some applications, a soluble resin can be used as the curable fluid. Suitable soluble resins include water-soluble resins that are soluble in water, organic solvent-soluble resins that are soluble in organic solvents, and the like. When these soluble resins are used in a mold for forming a second article, the resin can often be removed from the second article by dissolution.

  When an inorganic material is used as the curable fluid, various inorganic materials such as glass, concrete, plaster, cement, mortar, ceramics, and metal can be used. These materials can often be cured by heating or moisture removal. It is also possible to use an organic-inorganic composite material that can be a composite material of any of the above organic materials and inorganic materials as the curable fluid.

  Providing the curable fluid on at least a portion of the mold surface can be accomplished by any known method. Some methods of providing a curable fluid use a mold having a depression and provide the curable fluid so that the depression is not filled or only partially filled. Some suitable methods of providing include coating, spraying, pouring, brushing, or pouring a curable fluid onto at least a portion of the mold surface. The coating can include, for example, adding a curable fluid to the surface and spreading the curable fluid over at least a portion of the surface. In many instances, the providing method includes a coating, and any suitable coating method can be used. In some coating methods, the curable fluid is provided using a knife coating method. The optimal delivery method can be selected based on the type of curable fluid, the desired shape of the article, the desired dimensions of the article, and the like.

  The curable fluid may be provided to the mold surface before the bubbles are provided or at the same time as the bubbles are provided. In many embodiments, at least one bubble is present while curable fluid is provided to the mold surface. For example, air bubbles can be present in the mold cavity. While providing the curable fluid to the mold surface, air bubbles can be encapsulated within the recess. Frequently provided bubble sizes, shapes, and locations can be selected and varied. For example, if the mold cavities are used to provide bubbles, the dimensions, shape, and position of these cavities can be varied.

  The curable fluid is in contact with the molding surface. That is, the curable fluid is in contact with at least one bubble at at least one location and in contact with the mold surface at at least one other location. When the curable fluid is cured, at least one recess is formed in a portion of the cured layer that has been in contact with at least one bubble that is part of the molding surface. When curing the curable fluid, the position of the at least one bubble can be controlled to be in place between the mold surface and the curable fluid. For example, bubbles can be confined in the recess of the mold. The size and shape of the recess can affect the size and shape of the bubbles and the size and shape of the recesses in the resulting cured layer. The size and shape of the recess can be varied to provide a plurality of recesses of different size and shape. For example, a plurality of bubbles can be provided by using a mold including a plurality of depressions. When multiple bubbles are provided, the size and shape of each bubble may be the same or different.

  The above process of manufacturing the article can be performed in air. In this embodiment, an article having at least one recess or an array pattern of recesses can be manufactured with a simple apparatus configuration that does not require a special apparatus such as an environmental chamber. For example, at least one bubble can be provided by encapsulation within at least one recess of the mold.

  In many cases, bubbles tend to form a spherical surface based on a balance of all forces that can affect its shape. These forces include the sum of the interfacial energy between the bubbles and the curable fluid, the interfacial energy between the mold surface and the curable fluid, and the interfacial energy between the mold surface and the bubbles. In addition to these forces, other process variables near the area where the bubble contacts the curable fluid, such as buoyancy, gravity, and viscosity of the curable fluid, can affect the shape of the bubble. When a substantially uniform force is applied to the bubble surface, or a substantially symmetric force is applied to the top of the bubble, the bubble is not deformed and has a relatively uniform and smooth convex surface. This shape is often a substantially spherical convex surface that can be adapted to a lens or the like. The bubble outline having a substantially spherical surface can be anti-transferred from the molding surface to an article made by curing the curable fluid. Accordingly, the recess provided by the portion of the bubble that contacts the curable fluid can include a recess having at least a substantially spherical surface.

  As used herein, the term “spherical surface” means that the surface can be considered to be part of a sphere, or that the surface has a spherical curvature. Some spherical surfaces can be considered to be dome-shaped or hemispherical. Other spherical surfaces can include portions that are smaller or larger than the hemisphere. As used herein, the term “substantially spherical” means that the surface can be considered to be generally part of a sphere, but can be slightly different from a perfect sphere. All of the substantially spherical surfaces can have the same or different curvatures and can include a mixture of spherical surfaces whose curvatures vary continuously with position.

  Some concave surfaces are asymmetric surfaces rather than symmetric spherical surfaces. A concave surface having an asymmetric shape can be imparted to the article by the outer surface of the bubble having an asymmetric shape. Asymmetrically shaped bubbles can be formed by applying an unequal force on the convex surface of the bubble, or by applying an asymmetrically distributed force on the convex surface of the bubble.

  Articles having at least one recess can be manufactured in a relatively simple process. A single recess can be formed on the surface of the article, or multiple recesses can be formed that can be arranged randomly or in a pattern. At least one recess can be spherical or substantially spherical and can be used as a lens. Articles having an array pattern of recesses, such as micro-recesses, can be manufactured in a simple process that is less time consuming and less costly than other known processes for manufacturing similar articles. It is also possible to modify the manufacturing process so that it can be carried out in a continuous manner and an article having any desired dimensions can be prepared.

  According to one embodiment of the present invention, the mold can include at least one indentation, and enclosing air bubbles in at least one indentation of the mold while providing a curable fluid to the mold surface. Thus, at least one bubble is intentionally introduced into the molding surface, and the shape of the bubble can be controlled by applying a potential difference between the mold and the curable fluid. That is, the bubbles are enclosed in the depression of the mold, positioned between the mold surface and the curable fluid, and the shape is controlled by applying a potential difference. The molding surface in contact with the curable fluid includes a combination of the mold surface (ie, the actual mold surface) and at least one cell.

  For example, the mold can include an array pattern of multiple indentations, and enclosing air bubbles in the array pattern of multiple indentations in the mold while providing a curable fluid to the molding surface, A plurality of bubbles are intentionally introduced into the molding surface, and the shape of the plurality of bubbles can be controlled by applying a potential difference between the mold and the curable fluid. That is, it is possible to enclose a plurality of bubbles in the plurality of depressions of the mold arranged in the pattern. Each of the plurality of bubbles can be enclosed in a mold cavity between the mold surface and the curable fluid, and the shape can be controlled by applying a potential difference. The molding surface in contact with the curable fluid includes a combination of the mold surface (ie, the actual mold surface) and a plurality of bubbles arranged in a pattern.

  In these embodiments, at least one indentation or an array of indentations is provided to the mold in advance, so that at least one indentation in the mold is provided while providing the curable fluid to the forming surface. Bubbles can be enclosed inside. The position of the at least one depression corresponds to the position of at least one bubble that is part of the molding surface. The position of at least one bubble corresponds to the position of a plurality of recesses that are imparted to an article made by curing the curable fluid that is in contact with the molding surface. Therefore, at least one recess can be reliably and easily positioned at a predetermined position on the article. Moreover, since the position of a hollow respond | corresponds to the position where several recessed part is formed with an article | item, the several recessed part which has a high positional accuracy can be formed on an article | item.

  In addition, the shape of the bubbles can be controlled by applying a potential difference between a part of the mold and the curable fluid. As a method of applying the potential difference, for example, using a power supply device, the positive electrode is connected to the mold, the negative electrode is connected to the conductive film, and a voltage is applied before providing the curable fluid between the conductive film and the mold. A method in which a curable fluid is provided between the conductive film and the mold and then a voltage is applied between the mold and the conductive film. Examples include a method of applying a voltage by connecting to a plate-like electrode and bringing the electrode into contact with a curable fluid on a mold. As the power supply device, an AC power supply device, a DC power supply device, a function generator, an amplifier, or the like can be used. The voltage to be applied is, for example, 1 V or more, 10 V or more, 100 V or more, and can be 5000 V or less, 3000 V or less, or 2000 V or less. If it is higher than 5000 V, the curable fluid may be decomposed depending on the material, and if it is lower than 1 V, the shape of the bubbles may not change.

  The volume of the mold cavity affects the amount of gas that can be enclosed in the cavity between the curable fluid and the mold surface. Where there are multiple depressions, the volume of the plurality of depressions can be similar, or any portion of the plurality of depressions can be similar. The size of any recess can be changed by changing the volume of the recess that encloses the bubble that creates that particular recess. For example, the first group of the plurality of recesses may have a first dimension that is different from the second group of the plurality of recesses having the second dimension.

  Any desired pattern of depressions can be included in the mold. For example, the array pattern of the depressions includes an array of lattice patterns such as an array of columns, a square lattice pattern, etc. (ie, the lattice pattern is a pattern having a plurality of rows, a plurality of columns, or both), an array A patterned zigzag pattern, or an array of radiation patterns. The depressions in the pattern can be the same size and shape, or can be different.

  According to the above embodiment, enclosing air bubbles in the mold cavity while providing the curable fluid to at least a portion of the mold surface results in the formation of air bubbles between the mold surface and the curable fluid. Can be provided. For example, while providing the curable fluid to the mold by coating or pouring, a portion of the total gas (e.g., air) present around the mold may be removed from the space between the curable fluid and the mold surface It can be enclosed in. The encapsulated air bubbles can become a part of the molding surface, and can give a concave portion to the cured layer. In this case, various coating devices such as knife coating devices, bar coating devices, blade coating devices, and roll coating devices can be used if coating is provided.

  In addition to providing a potential difference between the mold and the curable fluid, the encapsulation of the at least one bubble may be, for example, the viscosity of the curable fluid, the coating speed, between the curable fluid and the gas and the mold. It can be controlled to some extent by adjusting factors such as various interfacial tension relationships. The state of the enclosed gas bubble, such as its size, shape, and position, is also controlled by similar factors as described above for the encapsulation of the gas bubble, such as the size, shape, and position of the recess in the mold. be able to. However, it is difficult to control the shape of the bubbles by adjusting the viscosity of the curable fluid after determining the shape of the recess and preparing the mold. It should be noted that the entire process can be performed under atmospheric pressure and does not need to be reduced.

  Another aspect of the present invention is an article having a surface including at least one recess, such as an array pattern of recesses manufactured according to the above manufacturing method. During manufacture, the one or more bubbles impart at least one recess, such as an array pattern of recesses, on the surface of the article.

  In one embodiment of the article, a molding surface comprising at least one cell can be used to form at least one smooth concave surface. When forming a plurality of recesses, the plurality of recesses can be arranged randomly or in a pattern. The array pattern of the recesses can be formed by using a molding surface including the array pattern of bubbles. This bubble arrangement pattern often corresponds to the depression pattern of the mold. Each of the generated smooth concave surfaces is a reversal of a portion of the outer surface of the bubble that is part of the molding surface. In many instances, the bubbles have a substantially spherical surface, and the resulting recesses imparted to the article have a substantially spherical surface.

  When the plurality of recesses are arranged in a pattern on the surface of the article, the pattern can be of any design. For example, the array pattern can be an array column pattern, an array grid pattern, an array zigzag pattern, or an array radiation pattern. The plurality of recesses can all be similar in size and shape, or any portion of the plurality of recesses can be similar in size and shape. In some articles having an array pattern of recesses, some or all of the plurality of recesses have a substantially spherical surface.

  Furthermore, a recess having an overhang shape that is difficult to form by conventional machining can be formed on the surface of the article.

  The articles described herein can be used in a variety of fields and applications. In particular, the article can be used for a variety of optical applications where at least one recess on the surface of the article is substantially transparent or translucent to visible light and has a substantially spherical surface. . For example, the concave portion can function as a lens such as a microlens. An array of a plurality of concave portions that are transparent or translucent to visible light and have a substantially spherical surface can be used as an array of lenses such as a microlens array.

  A first article having a surface including at least one recess such as an array pattern of recesses is a mold for producing a second article having at least one protrusion on the surface such as an array pattern of protrusions ( That is, it can be used as a second mold). The at least one convex portion on the second article is an inversion of at least one concave portion present on the first article used as the second mold. That is, an arbitrary concave portion present in the first article can be provided as a convex portion on the second article.

  The term “at least one convex portion” refers to a single convex surface or a plurality of convex surfaces. A mold with at least one concave surface can be used to impart at least one convex surface to the article. The “projection pattern” is a pattern of a plurality of projections arranged at a predetermined position, arranged with a certain degree of regularity, or arranged in any desired manner. For example, the arrangement pattern of the protrusions may include an array pattern such as an array column pattern, an array of square lattice patterns, an array of zigzag patterns, or an array of radiation patterns. The arrangement pattern of the convex portions does not need to be formed uniformly on the entire article, and may be formed only on a part of the article. The pattern of protrusions may or may not change over any part of the article. For example, similar or different patterns can be used in the same plane. The plurality of protrusions in the pattern can be of the same size and shape, or can have different sizes and shapes.

  A relatively simple process and relatively short compared to other conventional methods of forming a similar article because the first article is used as a second mold to form the second article. In the manufacturing time, the second article having at least one convex portion such as an array pattern of convex portions can be formed. More specifically, a second article having at least one substantially spherical convex surface, such as an array pattern of convex surfaces, is formed using a first article having at least one substantially spherical concave surface. be able to. The at least one convex surface formed on the second article can be, for example, a minute convex portion.

  Accordingly, another aspect of the present invention is a second article having a surface including at least one convex portion, such as an array pattern of convex portions. In this method, in order to impart at least one convex portion such as an array pattern of convex portions to the surface of the second article, the first article produced by the above manufacturing method is used as the second mold. including.

  The second article can be manufactured by providing a second curable fluid to the first article using a providing method such as coating or pouring. The second curable fluid is provided on the surface of the first article including at least one recess. Suitable second curable fluids are often of the same type as the curable fluids that can be used to make a first article with at least one recess. The second curable fluid is typically selected to be compatible with the first article used as the second mold. More specifically, in many cases, the second curable fluid is selected so as not to dissolve or change the shape and dimensions of the second mold. Examples of the second curable fluid include organic materials, inorganic materials, and organic-inorganic composite materials that are in the form of gels, pastes, liquids, dispersions, suspensions, and the like. Encapsulated, such as bubbles encapsulated between the surface of the second mold and the second curable fluid, after the curable fluid is provided to the second mold but before it is cured A degassing process can be added to remove bubbles. In some examples, the presence of encapsulated bubbles can cause a malfunction in the second article.

  In some examples, the at least one convex portion has a substantially spherical surface and the process involves the use of a second mold having at least one concave portion with a substantially spherical surface. The diameter of the at least one recess of the second mold is often less than 1000 micrometers, less than 100 micrometers, or less than 10 micrometers. The at least one convex portion formed in the second article has a diameter that is approximately the same as the diameter of the at least one concave portion existing in the second mold. Producing a second mold using at least one bubble, such as an array pattern of bubbles in the molding surface, that provides at least one recess, such as an array pattern of recesses, on the surface of the second mold. .

  In some representative second articles, the at least one protrusion is a substantially spherical surface. If the at least one protrusion is substantially transparent or translucent in the visible region, it is possible to use the second article in various optical fields. More specifically, at least one convex portion can be used as a lens such as a microlens, and an array pattern of convex portions can be used as an array of lenses such as a microlens array.

  If there are more than one protrusion on the surface of the second article, all or any of the plurality of protrusions can be similar. For example, a first group of a plurality of convex portions having substantial similarity, and a second group of a plurality of convex portions having substantial similarity but different from the first group of the plurality of convex portions, , Can exist.

  The surface of the second article can be covered with a first article that functions as a second mold. In this case, the second article is not removed from the first article during the manufacturing process. Such a combined article composed of both a first article and a second article can be used in various fields. For example, if the first article and the second article are made using materials with different refractive indices, the combined article will serve as a lens even if the combined article has a flat surface. Can function.

  One exemplary process for making a first article having at least one recess and a second article having at least one protrusion is shown schematically in FIGS. 3A-3H. More specifically, FIGS. 3A-3E schematically illustrate one embodiment of a manufacturing method for making an article having a surface that includes a plurality of recesses, such as an array pattern of recesses. 3F to 3H schematically show an embodiment of a manufacturing method for producing a second article having a surface including a plurality of protrusions, such as an array pattern of protrusions.

  3A-3E schematically illustrate one exemplary manufacturing process that can be used to manufacture an article 331 having a plurality of concave surfaces 332. FIG. 3A shows a process of providing a mold 310 having a plurality of depressions 311. The mold may include a dielectric layer 314. FIG. 3B shows a process of providing the conductive film 315 on the side of the mold 310 having the depression 311 and applying a potential difference 317 between a part of the mold 310 and the conductive film 315. FIG. 3C shows the process of providing the mold 310 with the curable fluid 330 and providing the bubbles 350. The bubble 350 is enclosed in the recess 311 and is positioned between the mold surfaces 312, 313 and the curable fluid 330. FIG. 3D shows the curable fluid 330 being cured to form an article 331 having an array pattern of a plurality of recesses 332 imparted by bubbles 350 on the surface. FIG. 3E shows the removal of the article 331 from the mold 310. The article 331 can form any desired number of recesses. The concave surface 332 is formed at a position corresponding to the depression 311 of the mold and corresponding to the position of the enclosed bubble 350. The outer shape of the bubble 350 is given to the article 331 to form a plurality of recesses 332. Each of the manufacturing processes of FIGS. 3A-3E can be performed with the mold 310 under ambient conditions. The molding process used to manufacture the article 331 need not be placed in a special environmental chamber.

  While providing the curable fluid 330 between the mold surface and the conductive film 315, the bubbles 350 are encapsulated. At this time, before providing the curable fluid 330 between the mold surface and the conductive film 315, a potential difference 317 may be applied between a part of the mold 310 and the conductive film 315, or the curable fluid may be provided. A potential difference 317 may be applied during or after provision of 330.

  In many embodiments, the curable fluid 330 includes a curable resin. The curable fluid 330 is preferably provided over the mold cavities in such a way that the plurality of cavities are not filled with the curable fluid 330. That is, the curable fluid 330 is preferably not in contact with the mold surfaces 312 and 313. However, the bubble 350 contacts the curable fluid 330 positioned over the mold surfaces 312 and 313 and the recess 311. The molding surface is the surface that is in contact with the curable fluid 330, the outer surface of the bubble 350 that is in direct contact with the curable fluid 330, and any portion of the mold surface that is in direct contact with the curable fluid 330. And both. For example, the portion between the mold recesses 311 is in direct contact with the curable fluid 330. After providing the curable fluid 330 and enclosing the bubbles 350, the curable fluid 330 is cured and removed from the mold 310. The obtained article 331 has a plurality of concave surfaces 332 to which a part of the outer shape of the bubble 350 is provided.

  If the mold includes a plurality of depressions 311, the plurality of depressions can be randomly arranged or arranged in any desired pattern. In some embodiments, the plurality of indentations 311 can be arranged in a single row or in a grid pattern. As used herein, a mold having a grid pattern of depressions means that there are at least two rows, at least two columns, or at least two rows and at least two columns of depressions 311 in the mold. means. For example, some lattice patterns are square lattice patterns with the number of rows equal to the number of columns. In other embodiments, the depressions can be arranged in a pattern, such as a zigzag pattern or a radiation pattern.

  In the process shown in FIG. 3A, a mold 310 having a plurality of depressions 311 is provided. The plurality of depressions 311 can be randomly arranged, or can be arranged in any desired pattern based on the use of the resulting article. The position of the recess 311 determines the position of the enclosed bubble 350 that provides at least one recess in the surface of the article. The positions of the plurality of recesses 332 on the surface of the article 331 can be selected by the arrangement of the recesses 311 on the mold 310.

  The recess 311 can have any suitable shape. The planar shape viewed from above the depression 311 can be, for example, a circle, a triangle, a square, a rectangle, an ellipsoid, a trapezoid, a pentagon, a hexagon, or a cross. For example, the recess 311 can have a triangular cross-section as shown in FIG. 3A.

  FIG. 4A is a schematic view from above, showing another exemplary mold 410 having a plurality of quadrangular pyramid depressions 411 with triangular planar sides. Each of the pyramids in FIG. 4A has a pointed base. FIG. 4B is a schematic view from above, showing yet another exemplary mold 410 having a plurality of square pyramid depressions 411 with rectangular planar side portions. Each of the pyramids in FIG. 4B has an edge line at the bottom.

  In other examples, the recess 311 can have a square cross section. The side surface may be formed in a linear shape or a curved shape. The bottom portion of the recess 311 that is a part of the surface of the mold may be configured in, for example, a planar shape, a pointed shape, a linear shape, or a circular shape. In yet another example, the recess 311 may have a trapezoidal cross-sectional shape, and the width of the cross section may decrease from the top to the bottom, or increase from the top to the bottom. The side surface and the bottom surface may be formed in a linear shape or a curved shape. Any other suitable shape for the recess 311 can be used.

The recess 311 can have any suitable dimension. As an example of the dimensions of the recess 311, the depth can be 0.1 μm or more, 1 μm or more, or 10 μm or more. In many cases, the depth can be 100 mm or less, 10 mm or less, or 1 mm or less. The cross-sectional area of the opening of the depression can be 0.01 μm ² or more, 0.1 μm ² or more, or 1 μm ² or more. The cross-sectional area can often be 1000 mm ² or less, 100 mm ² or less, or 10 mm ² or less. However, the dimensions are not limited to these values.

  In the process shown in FIG. 3C, the laminate roll 340 is set adjacent to the mold 310. By the laminating roll 340, the conductive film 315 covers the coating composition coated on at least a part of the mold 310 to form the curable fluid layer 330. The curable fluid layer 330 does not fill the depression 311. That is, the curable fluid 330 does not contact a part of the mold surface. At the same time, bubbles 350 are provided in the recesses 311 of the mold 310. The coating process can also be performed in air under standard atmospheric conditions.

  In some embodiments of the coating process shown in FIG. 3C, the curable fluid comprises a curable polymer resin. Any suitable polymer resin can be used alone or in combination with other polymer resins. For example, the curable fluid can be a solution of a polymer resin such as a photocurable resin (eg, an ultraviolet curable resin) or a soluble resin (eg, a water soluble or organic solvent soluble resin). When the mold 10 has sufficient heat resistance, the polymer resin can be a thermoplastic resin or a thermosetting resin. Any polymer resin can contain various additives, such as thickeners, curing agents, crosslinking agents, initiators, antioxidants, antistatic agents, diluents, detergents, pigments, or dyes.

  Representative photocurable resins include, but are not limited to, photopolymerizable monomers, oligomers, or mixtures thereof. Photopolymerizable monomers include acrylate monomers, methacrylate monomers, and epoxy monomers. Photopolymerizable oligomers include acrylate oligomers, methacrylate oligomers, urethane acrylate oligomers, epoxy oligomers, epoxy acrylate oligomers, and ester acrylate oligomers. Usually, a photoinitiator is added to the photocurable resin. When an ultraviolet curable resin is used, the resin can be rapidly cured using ultraviolet rays without exposing the mold or the like to a high temperature.

  Typical thermosetting resins that can be included in the curable fluid include acrylate resins, methacrylate resins, epoxy resins, phenol resins, melamine resins, urea resins, unsaturated ester resins, alkyd resins. A resin, a urethane-based resin, or a hard rubber-based resin can be used, but the present invention is not limited thereto. Typically, a polymerization initiator is added to the thermosetting resin. The resulting cured polymer material can have good heat resistance and solvent resistance. Furthermore, when filler is added, the resulting cured polymeric material can be very strong.

  Exemplary thermoplastic resins that can be included in the curable fluid include, but are not limited to, polyolefin resins, polystyrene resins, polyvinyl chloride resins, polyamide resins, or polyester resins.

  Exemplary soluble resins that can be included in the curable fluid include, but are not limited to, water soluble resins and organic solvent soluble resins. Suitable water soluble resins include, for example, polyvinyl alcohol, polyacrylic acid, polyacrylic amide, and polyethylene oxide.

  Any suitable curing method can be used. The curing method is typically selected based on the composition of the curable fluid. Some curing methods include a drying process to remove water or organic solvents. Other curing methods involve exposing the curable fluid to actinic radiation such as ultraviolet light. Still other curing methods include exposing the curable fluid to heat or cooling the curable fluid.

  The average thickness of the curable fluid layer 330 can be any desired thickness and can vary depending on the desired article. In some examples, the average thickness of the curable fluid layer 330 is about 10 μm to 100 mm, or 10 μm to 10 mm.

  The inclusion of the bubble 350 in the recess 311 adjusts factors such as, for example, the viscosity of the curable fluid 330, the coating speed, and the interfacial tension relationship between the curable fluid 330, the bubble 350, and the mold 310. It is possible to control by. For example, if the coating speed is higher than the natural flow rate of the curable fluid on the surface of the mold cavity, it is possible to enclose gas bubbles in each mold cavity. Natural flow rate means the flow rate of the curable fluid placed on the mold, for example, the influence of the viscosity of the curable fluid and the relationship between the interfacial tension between the curable fluid, the gas and the mold. There is a case to receive. When the viscosity of the curable fluid is low, the bubbles 350 can be encapsulated by increasing the coating speed or changing the material of the mold.

  In FIGS. 3C and 3D, the bubble 350 is positioned in the recess 311, but is not limited thereto. That is, the outer surface of the bubble 350 can be outside the depression 311.

  In the process shown in FIG. 3D, the curable fluid layer 330 is cured to form a cured layer 331. Any suitable curing method adapted to cure the fluid 330 can be used. For example, when the curable fluid is an ultraviolet curable resin, the cured layer 331 can be formed by polymerizing the resin by irradiating the curable fluid layer 330 using an ultraviolet light source. When the curable fluid layer contains a soluble resin, the cured layer 331 can be formed by drying to remove the solvent. When the curable fluid is a thermoplastic resin, the cured layer 331 can be formed by cooling the thermoplastic resin to at least the softening temperature. When the curable fluid is a thermosetting resin, the cured layer 331 can be formed by heating the thermosetting resin to at least the curing temperature.

  The cured layer 331 as shown in FIG. 3E has a plurality of concave surfaces 332 that result from contacting the outer surface of the bubble 350 during curing. That is, the outer shape of the bubble 350 that can have a substantially spherical surface is transferred back to the hardened layer 331. That is, the outer shape of the bubble 350 is a part of the molding surface that comes into contact with the curable fluid 330. The hardened layer 331 has the reverse shape of the molding surface.

  Bubbles 350 are part of the molding surface, which is the operating surface that contacts the curable fluid 330. Since the bubble 350 is part of the molding surface and the bubble 350 often has a substantially spherical convex outer surface, the cured layer 331 often has a substantially spherical concave surface. The plurality of recesses formed in the hardened layer 331 can be a plurality of minute recesses.

  In the process shown in FIG. 3E, an article (ie, a cured layer) 331 having a plurality of concave surfaces 332, such as a plurality of microrecesses, can be obtained by removing or separating the cured layer 331 from the mold 310. In some embodiments, the mold 310 can be used to form other cured layers 331. Article 331 having at least one recess can be used as an optical article, such as a lens or an array of lenses, or can be used to make a second article having at least one protrusion.

  In some embodiments of the article 331, the first surface of the article has a plurality of recesses and the second surface opposite the first surface is flat. The flat surface can be a matte finish or a glossy finish. The surface roughness of either surface can be, for example, less than 100 nanometers, less than 50 nanometers, less than 10 nanometers, or less than 5 nanometers.

Article 331 manufactured through the process of the steps of FIGS. 3A-3E has a surface that is a reversal of the molding surface used to form the article. More specifically, article 331 has a plurality of recesses provided by portions of the outer surface of bubble 350. In many cases, the shape of the recess 332 is a substantially spherical inversion with a curvature determined by the dimensions of the bubble 350. Depending on the application of the article 331, the plurality of recesses can have any suitable dimensions. The cross-sectional area of the bottom portion of some exemplary plurality of recesses is about 0.01 μm ² or more, 0.1 μm ² or more, or 1 μm ² or more. This cross-sectional area is often 100 mm ² or less, 10 mm ² or less, or 1 mm ² or less. In many cases, the height of the recess 332 is 0.1 μm or more, 10 μm or more, or 10 μm or more. This height can be, for example, 100 mm or less, 10 mm or less, or 1 mm or less.

  The size (eg, volume, diameter, or cross-sectional area) of the bubble 350 may be determined by, for example, (a) adjusting the size and shape of the recess 311 of the mold 310, and (b) the curable fluid provided to the mold 310. Adjusting the viscosity of 330, (c) adjusting the rate at which the curable fluid 330 is provided to the mold 310, and (d) adjusting the interfacial tension between the curable fluid 330, the mold 310 and the bubbles 350. (E) adjusting the time from coating of the curable fluid 330 to its curing; (f) adjusting the temperature of the bubble 350; and (h) adjusting the pressure applied to the bubble 350; It may be controlled by. Specific dimensions of the bubble 50 that can be adjusted in the above manner can have a diameter in the range of, for example, 0.1 μm to 100 mm.

  In another aspect, a method is provided for making a second article having at least one protrusion from an article having at least one recess. An article having at least one recess is used as a mold (second mold) to form a second article. 3F to 3H show an embodiment of a method for manufacturing the second article. In this embodiment, the article 331 manufactured as shown in FIGS. 3A to 3E can be used as the second mold. A second curable fluid 360 is provided to the second mold 331 and cured to form a second article 361 having a plurality of convex surfaces 362. 3E to 3G are schematic cross-sectional views showing individual manufacturing processes for manufacturing the second article 361 having a plurality of convex surfaces 362.

  Similar to the manufacturing process schematically shown in FIGS. 3A-3E, the manufacturing process shown in FIGS. 3F-3H may also be performed in air. In FIG. 3F, a second mold 331 having a plurality of concave surfaces 332 is provided. In FIG. 3G, a second curable fluid 360 is provided to the second mold 331. The second curable fluid 360 is cured to become the second cured layer 361. In FIG. 3H, the second cured layer 361 is removed from the second mold 331 to obtain a second article having a plurality of convex surfaces 362. The shape of the plurality of convex portions 362 corresponds to the shape of the bubbles 350 used for providing the second mold 331 with a plurality of concave portions.

  In FIG. 3F, a second mold (first article) 331 is provided that can be manufactured using the process schematically illustrated in FIGS. 3A-3E. In some embodiments, the second mold 331 is made from a curable fluid 330 selected from, for example, an ultraviolet curable resin, a soluble resin, a thermoplastic resin, a thermosetting resin, and the like. Any of the curable fluids described above can be cured to form the second mold 331.

  In FIG. 3G, a second curable fluid 360 is provided to the second mold 331. Any suitable providing method can be used, but in many cases the curable fluid 360 is provided to the second mold 331 using a coating process. However, in contrast to the process schematically shown in FIG. 3C, air bubbles are typically not intentionally encapsulated during the process shown in FIG. 3G. Methods that can be difficult to use in the process of FIG. 3C can be used in the process of FIG. 3G. For example, a process such as pouring, heating and pressing, or electroforming can be used to provide the second curable fluid 360 to the second mold 331.

  Second curable fluid 360 can be any material described above for use as curable fluid 330. In some examples, the second curable fluid 360 may be selected to be a UV curable resin or a soluble resin. When the second mold 331 has sufficient heat resistance, a thermoplastic resin or a thermosetting resin can be used for the second curable fluid 360. The second curable fluid 360 contains, for example, an additive such as a thickener, a curing agent, a crosslinking agent, a reaction initiator, an antioxidant, an antistatic agent, a diluent, a detergent, a pigment, or a dye. Can do.

  In some applications, such as those using at least one convex portion as a lens, the second curable fluid 360 is a polymer resin that results in the formation of a cured layer with good optical properties. For example, the polymer resin can be a polycarbonate resin, an acrylic resin, a polyester, an epoxy resin, a polyurethane, a polyamide, a polyolefin, or a polymer resin including silicone (modified silicone such as polyurea silicone) or similar material.

  In many cases, the curable fluid 360 is provided to the second mold 331 using a coating method, although other suitable providing methods can be used. Suitable coating equipment includes, but is not limited to, knife coating equipment, bar coating equipment, blade coating equipment, and roll coating equipment. If a coating method is used, a degassing process can be added before and after coating the second curable fluid 360 to remove any bubbles or air that may cause failure of the second article. . A suitable deaeration process often includes a vacuum step. The deareation process often removes air bubbles or air in the second curable fluid 360 or between the second curable fluid 360 and the second mold 331. Can do.

  The second curable fluid 360 is cured to form a second cured layer 361. When the second curable fluid is an ultraviolet curable resin, the second cured layer 361 can be formed by irradiation with ultraviolet rays. When the second curable fluid 360 is a soluble resin solution, the solvent can be removed by drying or the like to form the second cured layer 361. In the case where the second curable fluid 360 is a thermoplastic resin, the second cured layer 361 can be formed by cooling the resin to at least the softening temperature. When the second curable fluid 360 is a thermosetting resin, the second cured layer 361 can be formed by heating the resin to at least the curing temperature.

  The second hardened layer 361 having a plurality of convex surfaces 362 can be formed by the process shown in FIG. 3G. The convex surface 362 is a reversal of the outer shape of the concave surface 332 of the second mold 331. Specifically, the convex surface 362 formed on the second hardened layer 361 is substantially similar to the outer shape of the bubble 350 used to give a plurality of concave portions to the second mold 331. It can be a spherical convex surface. Thus, a second article having at least one substantially spherical convex surface, such as an array pattern of substantially spherical convex surfaces, can be produced.

  In the process shown in FIG. 3H, the second article 361 having a plurality of convex surfaces 362 can be obtained by removing the cured layer 361 formed by the process shown in FIG. 3G from the second mold 331. It is also possible to coat another resin material or the like on the convex surface 362 of the manufactured second article 361.

  A second article can be made using a continuous manufacturing process. By repeatedly supplying the additional second mold 331 to the coating apparatus, it is possible to repeatedly provide the second curable fluid 360 to each additional second mold 331. Each additional curable fluid 360 can be cured to form a second article 361 having at least one protrusion. By repeating the process shown in FIGS. 3A-3E and the process shown in FIGS. 3F-3H, an article 331, each having a plurality of concave surfaces 332, and a second article 361, each having a plurality of convex surfaces 362. Can be manufactured continuously.

The manufactured second article 361 is an article having at least one convex surface 362. Some second articles have an array pattern of convex portions such as a lattice pattern. Often, the convex surface 362 is a substantially spherical convex surface that corresponds to the outer surface of the bubble 350 used to form a plurality of recesses in the second mold 331. When measured by the cross-sectional area of the substrate, the dimension of the convex surface 362 is often in the range of 0.01 μm ^{2 to} 1000 mm ² . In many cases, the height of the convex surface 362 is in the range of 0.1 μm to 100 mm. Multiple protrusions outside this range can also be made, the dimensions of which are determined by the particular application selected for the article.

  In some second articles 361, there are a plurality of convex portions arranged in a pattern. Some arrangement patterns are arranged in a lattice pattern such as an arranged square lattice pattern. In addition, some articles have substantially identical convex surfaces 362. If the convex surfaces 362 are spherical and substantially transparent or translucent, they can be used as a lens or an array of lenses. A part of the convex portion 362 can be used as a microlens or a microlens array.

  Further, the second article 361 can have another layer of material coated on the convex surface 362. In that case, when using the convex surface 362 as a lens, a coating layer can be used as a protective layer, or it can be used in order to adjust a refractive index. By coating materials having various refractive indices as the outermost layer of the lens, lenses having a wide range of refractive indices can be obtained.

  When the second article 361 is formed using the first article 331 as a mold, it is not necessary to remove the first article 331 from the second article 361. That is, the first article 331 can remain adjacent to the second article 361. For example, the second article 361 can be stacked on the first article 331. Another single coating layer or multiple coating layers may be formed on the second article 361. In this case, the first article 331 remaining on the second article 361, or any additional coating layer, serves as a protective layer for the second article 361 or to adjust the optical properties of the second article 361. Can be used as a layer.

  In addition to using the first article or the second article as a lens or an array of lenses, the first article or the second article can be used as a mold. For example, a metal stamper can be made using a first article or a second article. In one exemplary process, a first metal layer, such as chromium or copper, can be deposited on the surface of the first article or on the surface of the second article. Next, a second metal layer, such as a nickel metal layer, can be deposited on the first metal layer. Subsequently, when the second metal layer is removed, a second metal stamper such as a nickel metal stamper having the same shape as the first article or the second article can be obtained.

  Embodiments of a method for manufacturing a first article having a surface comprising at least one recess or an array pattern of recesses, a method for manufacturing a second article using the first article as a second mold, first The second article and the second article are not limited to those described above, and various other embodiments are within the scope of the invention.

  Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto.

  Curable fluid: UV curable resin was used as the curable fluid. The ultraviolet curable resin composition comprises 90 parts by weight (pbw) of a polyester urethane acrylate (commercially available from Daicel Ornex Co., Ltd. under the trademark EBECRYL 8402) and 10 pbw of non-curable resin. Saturated aliphatic acid hydroxyalkyl ester modifier ε-caprolactone (commercially available from Daicel Chemical Industries under the trademark PLACEL FA2D) and 1 pbw of photoinitiator (IRGACURE from Ciba Specialty Chemicals) 2959, which is commercially available at 2959).

  Conductive mold: The conductive mold used was a nickel-plated copper substrate. This mold had a quadrangular pyramid shaped depression with a depth of 51.4 μm, apex angle of 88.4 degrees, and a square bottom shape. Each side of the square bottom was 100 μm. The depressions were arranged in a square lattice pattern with a pitch of 100 μm. The conductive mold was 50 mm × 50 mm in size. FIG. 5 shows a photograph of the conductive mold taken from above using an optical microscope (OLYMPUS, BX60).

  Low surface energy dielectric layer: Using the plasma processing equipment WAFORBATCH 7000 (Plasma Therm Industrial Products, Inc.), the following processing is performed on the conductive mold to form a low surface energy dielectric layer. did.

Dielectric mold 1:
The chamber of the plasma processing apparatus was depressurized until the pressure became 30 mTorr or less, and then the surface of the conductive mold was cleaned at an oxygen gas flow rate of 500 sccm, 13.56 MHz, and an output of 1 kW for 2 minutes. Next, the surface of the conductive mold was further cleaned at an argon gas flow rate of 100 sccm, 13.56 MHz, and an output of 1 kW for 1 minute.

  The surface of the cleaned conductive mold was treated in the presence of tetramethylsilane (TMS) and oxygen at a TMS / oxygen gas flow rate of 75/250 sccm and an output of 1 kW for 5 minutes. Next, similarly, the surface of the conductive mold was treated for 2 minutes at a TMS / oxygen gas flow rate of 10/300 sccm and an output of 1 kW. Then, after returning the inside of a chamber to atmospheric pressure, the electroconductive mold was taken out from the chamber.

  A hydrofluoroether (HFE) solution of 1.0% by weight of trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane (manufactured by Tokyo Chemical Industry Co., Ltd.) was prepared. As the HFE, 3M (registered trademark) NOVEC (registered trademark) highly functional liquid 7200 manufactured by 3M was used. The surface-treated conductive mold was immersed in this solution for 2.5 hours. Thereafter, the conductive mold was slowly taken out of the solution and held in an oven at 150 ° C. for 10 hours to form a low surface energy dielectric layer, whereby a dielectric mold 1 was obtained.

Dielectric mold 2:
The cleaning treatment and surface treatment of the conductive mold were performed in the same manner as in Example 1 until the treatment with the TMS / oxygen gas flow rate of 10/300 sccm. Thereafter, the surface of the conductive mold was further treated with octafluoropropane (C ₃ F ₈ ) gas flow rate of 300 sccm and output of 100 W for 2 minutes. After returning the inside of the chamber to atmospheric pressure, the conductive mold was taken out of the chamber to obtain a dielectric mold 2 on which a low surface energy dielectric layer was formed.
<Example 1>
After preparing the ultraviolet curable resin, the dielectric mold 1 was placed on a granite plate equipped with a laminate roll and an ultraviolet irradiation system. A dam was formed by arranging a spacer around the dielectric mold 1 so that an interval of about 300 μm was left between the spacer and the dielectric mold 1. Next, the positive electrode side plug of the DC power source (ZX-400H manufactured by Takasago Seisakusho) and the side edge portion of the dielectric mold 1 were electrically connected. A conductive film (ITO / PET sheet) in which an ITO film (55 ohm / □) is laminated on a polyethylene terephthalate film (MELINEX (registered trademark) ST506, manufactured by Teijin DuPont, Ltd., thickness 0.005 inch) is placed so that the ITO film side faces downward. Was placed on the dielectric mold 1. After electrically connecting the ITO film and the negative electrode side of the AC power source, the laminate roll was lowered onto the ITO / PET sheet, and the ITO / PET sheet was wound around the laminate roll as shown in FIG. 3B.

  Next, an AC voltage of 500 V was applied between the dielectric mold 1 and the ITO film. Thereafter, the prepared UV curable resin is dropped along the surface of the dielectric mold 1 and moved under the laminate roll at a constant speed of about 16 cm / sec. Spread on the mold surface. The coating layer was laminated with the ITO / PET sheet by moving the ITO / PET sheet together under the laminating roll together with the coating speed. During this coating, air bubbles were trapped in each recess of the base mold.

  A coating layer of an ultraviolet curable resin was formed on the surface of the dielectric mold 1 after coating, and a state in which the coating layer was laminated with an ITO / PET sheet was obtained.

  Thereafter, using an ultraviolet lamp (manufactured by USHIO), the ultraviolet curable resin coated via the ITO / PET sheet was irradiated with 3450 mJ / cm 2 of ultraviolet rays to polymerize and cure the ultraviolet curable resin. Thereafter, the cured layer was released from the dielectric mold 1 together with the ITO / PET sheet to obtain a first article 1 having an arrayed concave pattern.

  The first article 1 was used as the next mold, and a structure having a convex pattern was produced under the following conditions.

Drop room temperature curable silicone resin (trade name: ELASTSIL RT601, 2 component type (mixed weight ratio: A solution: B solution = 90:10), manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) onto the surface of the first article 1 with irregularities. did. Thereafter, in order to prevent bubble defects, deaeration was performed by reducing the pressure to 1000 Pa or less for 15 minutes. Subsequently, a silicone resin was spread using a knife coater to obtain a coating layer having a thickness of 200 μm. This coating layer was cured by leaving it to stand overnight (about 24 hours) at room temperature (about 25 ° C.) under reduced pressure (1000 Pa or less). The hardened layer was released from the first article 1 to obtain a second article 1 having a convex pattern obtained by inverting the concave pattern. A scanning electron microscope (SEM) image photograph of the obtained second article 1 is shown in FIG. A convex lens shape array having a shape extending in one direction corresponding to each concave shape of the base mold was obtained.
<Example 2>
A first article 2 and a second article 2 were obtained in the same manner as in Example 1 except that the dielectric mold 2 was used and the applied AC voltage was changed to 300V.
<Example 3>
A first article 3 and a second article 3 were obtained in the same manner as in Example 1 except that the dielectric mold 2 was used and the applied AC voltage was set to 100V.
<Example 4>
The first article 4 and the second article were the same as in Example 1 except that a 200 V AC voltage was applied between the dielectric mold 1 and the ITO film after laminating the coating layer with the ITO / PET sheet. 4 was obtained. An SEM image of the obtained second article 4 is shown in FIG.
<Example 5>
The first article 5 and the second article were the same as in Example 1 except that the coating layer was laminated with the ITO / PET sheet and then an AC voltage of 500 V was applied between the dielectric mold 1 and the ITO film. 5 was obtained. An SEM image of the obtained second article 5 is shown in FIG.
<Comparative Example 1>
A first article 6 and a second article 6 were obtained in the same manner as in Example 1 except that no AC voltage was applied. An SEM photograph of the obtained second article 6 is shown in FIG.
<Comparative Example 2>
A first article 7 and a second article 7 were obtained in the same manner as in Example 1 except that the dielectric mold 2 was used and no AC voltage was applied.
<Evaluation method>
The characteristics of the second articles obtained in Examples 1 to 5 and Comparative Examples 1 to 2 were evaluated according to the following methods.
<Optical characteristics>
The shape and optical characteristics of the convex lens on the surface of the second article in Examples 1 to 3 and Comparative Examples 1 and 2 were measured using a microlens array shape / optical characteristic evaluation device “NH-3MA” (Mitaka Kogyo Co., Ltd.). ). For the measurement, 5 × 5 convex lens shapes are used, and the radius of each lens, the focal length of the lens, and the spread in the x direction at the focused position (spot radius− x), and the average value and standard deviation (std) of the spot radius-y at the focused position were measured. The results are shown in Table 1.

<Surface shape>
The surface of the second article of Example 1, Example 4, Example 5, and Comparative Example 1 was observed with SEM (VE-8800 manufactured by Keyence Corporation). Each SEM photograph is shown in FIGS. The curvature radius was different between Example 1 to which voltage was applied and Comparative Example 1 to which no voltage was applied, and the curvature radius of Example 1 was smaller. However, in both samples, the uniformity of individual lens shapes was maintained.

In Example 4 and Example 5, the radius of curvature was smaller than that in Comparative Example 1 in which no voltage was applied, but uniformity was not maintained between the individual lenses in Examples 4 and 5. This non-uniformity is considered to be caused by applying a voltage after laminating the coating layer with an ITO / PET sheet.
<Cross sectional shape>
The second article of Example 1 and the second article of Comparative Example 1 were cut using a razor blade along the dotted line 1001 in FIG. 10A and the dotted line 1002 in FIG. 10B, respectively, and the cut surface was optical microscope (Olympus). This was observed with an optical microscope BX60 manufactured by Kogaku Kogyo Co., Ltd. In Example 1, the radius of curvature of the observed cross-sectional shape of the lens was about 40 μm, whereas in Comparative Example 1, it was 50 μm.

DESCRIPTION OF SYMBOLS 110 Mold 112 Mold surface 130 Hardening fluid 170 Bubble tangent 202 Electrode 203 Dielectric layer 204 Droplet 310 Mold 311 Depression 312, 313 Mold surface 315 Conductive film 317 Potential difference 330 Curing fluid 331 Article 332 Recess 340 Laminate roll 350 Bubble 360 Second curable fluid 361 Second article 362 Convex 410 Mold 411 Dimple

Claims (7)

A method for producing an article having a surface comprising at least one recess,
Providing a curable fluid on at least a portion of the mold surface;
Introducing at least one bubble between the surface of the mold and the curable fluid;
Changing the angle α between the tangent of the bubble and the surface of the mold by applying a potential difference between at least a part of the mold and the curable fluid; and Using as part, providing at least one recess in the curable fluid.   The method according to claim 1, further comprising disposing a conductive film so that the curable fluid is in contact with a surface where the curable fluid is not in contact with the mold.   Giving a potential difference between at least a part of the surface of the mold and the curable fluid means that after the potential difference is applied between the conductive film and the mold, the surface of the mold is cured. The method of claim 2, comprising providing a fluid.   The method according to claim 1, further comprising curing the curable fluid after applying the at least one recess to the curable fluid.   Providing a potential difference between at least a portion of the surface of the mold and the curable fluid includes providing a plurality of potential differences depending on location between the surface of the mold and the curable fluid; The method of any one of Claims 1-4.   The method according to claim 1, wherein the angle α is decreased by applying the potential difference.   The manufacturing method of the 2nd article | item which has the surface containing at least 1 convex part including using the article manufactured by the method of any one of Claims 1-6 as a shaping | molding die.