JP2006065303A - Antireflection structure and optical member having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably and easily mass-produce an antireflection structure having fine ruggedness and an optical member having the antireflection structure at a low cost. <P>SOLUTION: Regarding the antireflection structure having an antireflection surface on which fine projections are formed, the ratio of the projections occupying the antireflection surface is within the extent of 10% to 90% to the effective area of the antireflection surface, and the projections are constituted of a mutually connectable basic shape. The basic shape is 30 nm to 20 nm in mean height, and 80 nm to 400 nm in mean diameter, and the arrangement of the basic shape on the antireflection surface is substantially irregular, the optical member having the antireflection structure, an original mold for molding the antireflection structure, a manufacturing method for the original mold and a manufacturing method for a reproduction mold are offered. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antireflection structure for preventing or reducing reflection of a surface of an optical member, particularly a light transmissive member, an optical member having this antireflection structure, a display device, and a solar cell panel. Furthermore, the present invention relates to a prototype and a method of manufacturing the same that enable mass production of such an antireflection structure easily and at low cost.

  2. Description of the Related Art Conventionally, in an optical member, particularly a light transmissive member, light reflection on the surface has been prevented or suppressed. For example, information display units of various information devices, for example, display units of televisions, computers, mobile phones, information terminals, solar cells, window glasses, mirrors, light receiving units of various optical elements, polarization of light, refraction or dimming By making the surface of a member such as a lens or a filter antireflective, the visibility of information display is improved, or the light use efficiency is improved.

Such antireflection can be performed by forming a fine uneven shape on the surface. Conventionally, a coating method using a coating liquid containing an antireflection material (for example, JP-A-10-13002) or vapor deposition is used. A method (for example, JP-A-2003-66203) or a diffraction grating manufacturing method (for example, JP-A-2003-344630) is employed.
Japanese Patent Laid-Open No. 10-13003 JP 2003-66203 A JP 2003-344630 A

  In an optical member, the minute uneven shape on the surface has a great influence on the optical characteristics of the optical member. Therefore, the uneven shape must be determined by comprehensively judging necessary antireflection properties and other optical characteristics. There is. However, in order to achieve the necessary antireflection properties, it is easy to make the surface of the optical material have a predetermined uneven shape and to mass-produce optical members having such a predetermined uneven shape stably and at low cost. Not.

  For example, the above-described coating method has a problem that it is difficult to apply to an optical member having a complicated geometric shape on the surface, the vapor deposition method requires an expensive reaction apparatus, and a diffraction grating. The manufacturing method has problems such as requiring a precise optical system for manufacturing the diffraction grating. In particular, in the case of the vapor deposition method and the diffraction grating manufacturing method, it is necessary to use an apparatus suitable for the size, shape, etc. of the optical member to be processed, but as the optical member becomes larger in recent years, an apparatus suitable for it is obtained. This is not economically advantageous.

  Therefore, it has been difficult to mass-produce the antireflection structure having a fine uneven shape and the optical member having such an antireflection structure stably, easily and at low cost.

  The present invention has been made in view of the above problems, and forms an antireflection structure in which predetermined fine protrusions are formed, an optical member having such an antireflection structure, and such an antireflection structure. The present invention relates to an original mold, a manufacturing method thereof, and a manufacturing method of a replication mold.

  Here, the “replication mold” is a mold capable of duplicating an antireflection structure having a predetermined convex portion according to the present invention and an optical member having such an antireflection structure, and a surface shape of the mold. Means an inverted type (so-called “negative type”) with respect to the antireflection structure. That is, the “replication mold” is a so-called stamper for producing an antireflection structure having a fine projection formed according to the present invention, and a mold having a recess on the mold surface.

  This “replication mold” (this replication mold has a predetermined concave portion formed on its surface) is firstly “a prototype for forming an antireflection structure” (this prototype is a predetermined pattern on its surface). Can be manufactured by transferring the original surface shape by one or more operations.

  Therefore, the antireflection structure according to the present invention is an antireflection structure having an antireflection surface having fine projections formed on the surface thereof, and the proportion of the projections occupying the antireflection surface is equal to that of the antireflection surface. It is in the range of 10% to 90% with respect to the effective area, and the convex portion is composed of a basic shape which may be connected to each other, and the basic shape has an average height of 30 nm to 200 nm and an average diameter of 80 nm to 400 nm. The arrangement of the basic shape on the antireflection surface is substantially irregular.

Here, the fine convex portion is based on the surface of the base material that can be regarded as being substantially flat over a micrometer unit region on the surface of the base material, for example, a region of 100 μm ² , and is formed on the surface as described below. It is the convex part comprised by the basic shape prescribed | regulated to.

  A basic shape refers to the element of the convex part prescribed | regulated by the said average height and the said average diameter. Here, the average height is measured at least once for each of the basic shapes of three or more convex portions, and the values are arithmetically averaged (additive). Average). In addition, the average diameter is measured at least once for each of the basic shapes of three or more convex portions, and the values are arithmetically averaged (arithmetic average). ).

  The elements of the basic shape constituting the convex part form the convex part when they form the convex part substantially independently of each other, for example, like a band or substantially connected to each other in a lump. There is a case. Whether the elements having the basic shape are independent or connected is determined from the shape between the elements obtained from the surface image and the cross-sectional image taken by the scanning electron microscope.

  Here, being substantially irregular means that the basic shape of the convex portion is not formed on the surface of the substrate with the calculated artificial distribution, and the basic shape of the convex portion is macroscopic. The basic shape of the convex part is virtually random, and is not distributed artificially or by self-organization in the form of a diffraction grating or a photonic crystal. It means that it is distributed. Among the substantially irregular arrangement of the basic shape of the convex portion of the present invention, the basic shape of several to several tens of convex portions happens to be a diffraction grating partly and infrequently on a micrometer scale. Although it is distributed like a photonic crystal, it is a coincidence product that is much smaller than a magnitude that exhibits a macroscopic light diffraction effect or an optical effect derived from a photonic crystal structure.

  In such an antireflection structure according to the present invention, preferably, the frequency distribution of the diameters of the basic shapes of the convex portions can be narrow.

  In such an antireflection structure according to the present invention, preferably, the frequency distribution of the diameters of the basic shapes of the convex portions is such that the number of convex portions having a diameter difference of 75 nm or less from the convex portion having the highest number frequency is The diameter difference from the convex part having the highest number frequency can be a narrow one that is 70% or more of the number of convex parts within 300 nm.

  In such an antireflection structure according to the present invention, preferably, the ratio of the number of the basic shapes of the convex portions not connected to each other to the total number of the basic shapes of the convex portions is 10% or more. Can do.

  The optical member according to the present invention has the antireflection structure described above.

  Such an optical member according to the present invention includes, as a preferred embodiment, one having the above-mentioned antireflection structure on the surface of a geometric optical functional shape.

  The display device according to the present invention has the antireflection structure described above.

  Such a display device according to the present invention includes, as a preferred embodiment, one having the antireflection structure on the surface of the geometric optical functional shape.

  Moreover, the solar cell panel by this invention has the said antireflection structure.

  Such a solar cell panel according to the present invention includes, as a preferred embodiment, one having the above-described antireflection structure on the surface of a geometric optical functional shape.

  A prototype for forming the antireflection structure according to the present invention is a prototype for forming an antireflection structure having an antireflection surface having fine convex portions formed on the surface, the base material, the base And the ratio of the convex portion occupying the antireflection surface is in the range of 10% to 90% with respect to the effective area of the antireflection surface. The basic shape has an average height of 30 nm to 200 nm and an average diameter of 80 nm to 400 nm, and the arrangement of the basic shape on the antireflection surface is substantially irregular. It is characterized by this.

  And, in the production method of the prototype for forming the antireflection structure according to the present invention, in producing the prototype, a base layer is formed on the surface of the base material by using an alternate adsorption method as desired, It includes a step of forming fine convex portions by immobilizing fine particles on the underlayer.

  The prototype manufacturing method for forming such an antireflection structure according to the present invention preferably comprises a combination of a step of immersing the base material in a positive electrolyte polymer aqueous solution and a step of immersing in a negative electrolyte polymer aqueous solution. The underlayer can be formed by the alternate adsorption method.

  The original manufacturing method for forming the antireflection structure according to the present invention can preferably include a step of attaching fine particles by applying a fine particle dispersion onto the underlayer.

  In the prototype manufacturing method for forming the antireflection structure according to the present invention, preferably, after the fine particles are attached, the surface to which the fine particles are attached can be subjected to a heat treatment and / or an overcoat treatment. .

  In the method of manufacturing a prototype for forming such an antireflection structure according to the present invention, preferably, the basic shape of the convex portion constituted by the fine particles has a convex shape whose bottom portion is not substantially a reverse tapered shape. Can be part.

  The basic shape of the convex portion having a shape other than the reverse tapered shape referred to here is a convex portion having a shape similar to a bowl shape or a mountain shape. For example, when the spherical particle is placed on a surface, the spherical particle It is a convex part of the shape which does not have the reverse taper-shaped skirt part made between the surface.

  The method for manufacturing a replication mold according to the present invention is a method for manufacturing a replication mold from the above-mentioned prototype, wherein the above-mentioned prototype is prepared, and the projection of the prototype is inverted using the prototype. Create a shaped resin negative mold, create a metal positive mold by the metal plating method from the resin negative mold, and further, from the metal positive mold obtained in the above process, a metal plating method To obtain a metal negative mold as a duplication mold for duplicating the antireflection structure.

  The antireflection structure according to the present invention is an antireflection structure having an antireflection surface having fine projections formed on the surface, and the proportion of the projections occupying the antireflection surface is an effective area of the antireflection surface. 10% to 90% of the convex portion, and the convex portion has a basic shape which may be connected to each other, and the basic shape has an average height of 30 nm to 200 nm and an average diameter of 80 nm to 400 nm, Since the arrangement of the basic shape on the antireflection surface is substantially irregular, it has excellent antireflection properties.

  In such an antireflection structure, the arrangement of the projections is substantially irregular according to microscopic observation of a microscope, and at the same time, the arrangement of the projections is substantially according to macroscopic observation with the naked eye. And is particularly excellent in the level of antireflection properties and its homogeneity.

  The optical member having such an antireflection structure effectively prevents light reflection, and improves the visibility in the case of an optical member for information display such as a display device. In the case of such a light receiving optical member, the light utilization efficiency is improved.

  Such an antireflection structure according to the present invention can be easily manufactured from a predetermined replication mold. That is, by preparing a duplication mold capable of forming the predetermined antireflection structure, and shaping the antireflection structure with the duplication mold, a large number of optical members having the antireflection structure can be duplicated. . According to such a method, an optical member having an antireflection structure having substantially the same shape can be manufactured from a single replication mold.

  Therefore, an optical member having a predetermined antireflection structure can be manufactured very stably, easily and at a low cost as compared with a method for producing a coating, vapor deposition or diffraction grating for each product.

  In the present invention, a predetermined antireflection structure can be easily formed even on an optical substrate having a complicated surface shape.

<Antireflection structure>
The antireflection structure according to the present invention is an antireflection structure having an antireflection surface having fine projections formed on the surface, and the proportion of the projections occupying the antireflection surface is an effective area of the antireflection surface. Is 10% to 90%, preferably 25% to 75%, and the protrusions have a basic shape which may be connected to each other, and the basic shape has an average height of 30 nm to 200 nm. , Preferably 60 nm to 180 nm and an average diameter of 80 nm to 400 nm, preferably 100 nm to 300 nm, and the arrangement of the basic shape on the antireflection surface is substantially irregular.

Here, the fine convex portion is based on the surface of the base material that can be regarded as being substantially flat over a micrometer unit region on the surface of the base material, for example, a region of 100 μm ² , and is formed on the surface as described below. It is the convex part comprised by the basic shape prescribed | regulated to.

  A basic shape refers to the element of the convex part prescribed | regulated by the said average height and the said average diameter. Here, the average height is measured at least once for each of the basic shapes of three or more convex portions, and the values are arithmetically averaged (additive). Average). In addition, the average diameter is measured at least once for each of the basic shapes of three or more convex portions, and the values are arithmetically averaged (arithmetic average). ).

  The elements of the basic shape constituting the convex part form the convex part when they form the convex part substantially independently of each other, for example, like a band or substantially connected to each other in a lump. There is a case. Whether the elements having the basic shape are independent or connected is determined from the shape between the elements obtained from the surface image and the cross-sectional image taken by the scanning electron microscope.

  Here, being substantially irregular means that the basic shape of the convex portion is not formed on the surface of the substrate with the calculated artificial distribution, and the basic shape of the convex portion is macroscopic. The basic shape of the convex part is virtually random, and is not distributed artificially or by self-organization in the form of a diffraction grating or a photonic crystal. It means that it is distributed. Among the substantially irregular arrangement of the basic shape of the convex portion of the present invention, the basic shape of several to several tens of convex portions happens to be a diffraction grating partly and infrequently on a micrometer scale. Although it is distributed like a photonic crystal, it is a coincidence product that is much smaller than a magnitude that exhibits a macroscopic light diffraction effect or an optical effect derived from a photonic crystal structure.

  The average height and average diameter of the basic shape can be obtained using a surface roughness meter, probe microscope, microscopic interferometer, etc. It is preferable to obtain it. The average height and average diameter are both arithmetic average (arithmetic mean) values, and it is necessary to measure at least three basic shapes once each. Depending on the degree of distribution of the basic shapes, preferably 5 or more It is preferable to measure the basic shape once or more each time to obtain an average value, and more preferably, measure 20 or more basic shapes one or more times to obtain the average value.

  When the ratio of the convex portion occupying the antireflection surface is less than 10% with respect to the effective area of the antireflection surface, the convex portion is too small to substantially function as an antireflection structure, If it exceeds 90%, it is not preferable because there are too many convex portions and it does not substantially function as an antireflection structure. When the average height of the basic shape is less than 30 nm, the height of the convex portion is too small to substantially function as an antireflection structure. On the other hand, when it exceeds 200 nm, the height of the convex portion is too large and unnecessary. It is not preferable because it exhibits light scattering properties. When the average diameter is less than 80 nm, the diameter of the convex portion is too small and the antireflection performance is insufficient. On the other hand, when the average diameter exceeds 400 nm, the convex portion has a too large diameter and expresses unnecessary light scattering. That is not preferable. The value obtained by dividing the average height by the average diameter is preferably in the range of 0.075 to 2.5, particularly preferably 0.2 to 1.8. When this value is less than 0.075, the function as an antireflection structure is insufficient. On the other hand, it is difficult to make a product exceeding 2.5 for manufacturing reasons.

  Moreover, it is preferable that the convex portions have the same size, that is, the frequency distribution of the diameters of the convex portions is narrow. Therefore, this convex portion has a frequency distribution of diameters, the number of convex portions having a diameter difference within 75 nm with respect to the convex portion with the highest frequency is within 300 nm, and the difference in diameter with the convex portion with the highest frequency within 300 nm. It is preferable that the number of protrusions is as narrow as 70% or more, particularly 80% or more.

  And it is preferable that the ratio of the said convex part which is not mutually connected with respect to the total number of the said convex part is 10% or more, especially 20% or more.

  In such an antireflection structure, the arrangement of the projections is substantially irregular according to microscopic observation of a microscope, and at the same time, the arrangement of the projections is substantially according to macroscopic observation with the naked eye. And is particularly excellent in the level of antireflection properties and its homogeneity.

  FIG. 3 is a diagram schematically showing a basic shape constituting the convex portion of the present invention, and FIG. 3 (a) is a plan view when a substantially independent basic shape is observed from the upper surface. FIG. 3B is a cross-sectional view showing a side surface of a substantially independent basic shape, and FIG. 3C is a plan view when the substantially connected basic shape is observed from the upper surface. FIG. 3D is a cross-sectional view showing the side surfaces of the basic shapes that are substantially connected. 3 (a) to 3 (d) show the basic shape when the basic shape is completely independent, when a plurality of basic shapes are connected together, or when they are in a single band. The diameter X and the height Y of the basic shape are shown.

<Prototype for forming antireflection structure>
A prototype for forming an antireflection structure according to the present invention is a prototype for forming an antireflection structure having an antireflection surface having fine convex portions formed on a surface thereof. The ratio of the convex portion occupying the antireflection surface is in the range of 10% to 90% with respect to the effective area of the antireflection surface, and the convex portions are connected to each other. The basic shape is an average height of 30 nm to 200 nm and an average diameter of 80 nm to 400 nm, and the arrangement of the basic shape on the antireflection surface is substantially irregular, It is characterized by.

  This prototype has information on fine projections on the antireflection structure according to the present invention on the surface of the prototype. The antireflection structure according to the present invention can be regarded as being formed from all or a part of the information on the fine protrusions on the surface of the prototype or a combination of a plurality of prototypes.

  Therefore, in the prototype according to the present invention, the ratio of the convex portion occupying the antireflection surface is 10% to 90%, preferably 25% with respect to the effective area of the antireflection surface, as in the antireflection structure. The convex portion has a basic shape which may be connected to each other, and the basic shape has an average height of 30 nm to 200 nm, preferably 60 nm to 180 nm, and an average diameter of 80 nm to 400 nm. , Preferably 100 nm to 300 nm, and the value obtained by dividing the average height by the average diameter is preferably in the range of 0.075 to 2.5, particularly preferably 0.2 to 1.8, and the basic shape In the antireflection surface is substantially irregular.

<Prototype manufacturing method>
The method for producing the prototype is arbitrary, but it can be preferably produced by the method for producing the prototype shown below.

  Therefore, in the method of manufacturing the prototype for forming the antireflection structure according to the present invention, in producing the prototype, the base layer is formed on the surface of the base material by using an alternate adsorption method as desired, It includes a step of forming fine convex portions by immobilizing fine particles on the underlayer.

  A particularly preferable prototype manufacturing method is to form a base layer by the alternate adsorption method by combining the step of immersing the base material in a positive electrolyte polymer aqueous solution and the step of immersing the negative electrolyte polymer aqueous solution. The method includes a step of attaching fine particles by applying a fine particle dispersion onto the formation, and after the fine particles are attached, the surface to which the fine particles are attached is subjected to a heat treatment and / or an overcoat treatment.

  The following shows a specific example of a preferable prototype manufacturing method with reference to FIG. 1 as necessary.

<< Overview >>
(1) Substrate Although any substrate can be used in the present invention, it is preferable that the base layer can be easily formed by an alternate adsorption method. As such a base material, for example, inorganic materials such as glass, metals such as nickel, and organic materials such as various polymer compounds can be used. The substrate may be transparent or opaque, but an ultraviolet curable resin is applied when producing the original mold and / or the replica mold (detailed below) according to the present invention. In this case, since the exposure from the substrate side becomes possible, a substrate having transparency is preferable.

  The substrate may be a plate (1) having a substantially flat plane as shown in FIG. 1 (a), a sheet or film, and may be regular or irregular or geometric. For example, the substrate surface may have a straight line, a curved line, a flat surface, a curved surface and / or an uneven shape that can obtain certain optical characteristics. For example, various shapes corresponding to the target optical member, for example, Fresnel lens, lenticular lens, lens array, hologram sheet, prism, light guide plate, light diffusion sheet, convex lens or concave lens shape can be used. . Furthermore, this base material may be cylindrical or columnar such as a metal roll or a metal cylinder.

  FIG.1 (b) shows the manufacturing method of the prototype of the optical member which used the Fresnel lens-shaped thing as a base material sheet (2), and the antireflection structure by this invention was formed in the Fresnel lens surface.

(2) Alternate adsorption method The underlayer can be formed using an alternate adsorption method. Here, the alternating adsorption method refers to a thin film composed of a positive electrolyte polymer and a thin film composed of a negative electrolyte polymer on a substrate by alternately immersing the base material in a positive electrolyte polymer aqueous solution and a negative electrolyte polymer aqueous solution. Is a method consisting of alternately generating. In such an alternate adsorption method, the number of times of immersion is usually determined by alternately immersing a substrate having an initial charge on the surface prior to immersion, if necessary, in a positive electrolyte polymer aqueous solution and a negative electrolyte polymer aqueous solution. It becomes possible to form a multilayer structure having the number of layers according to the above.

  The number of immersions in the positive electrolyte polymer aqueous solution and the number of immersions in the negative electrolyte polymer aqueous solution can be appropriately determined according to the required performance as the underlayer, the thickness of the underlayer, and the like.

  Here, the required performance as the underlayer is a performance that imparts to the base material an electric charge sufficient for adhering a necessary amount of fine particles to be described later. In general, the thicker the underlayer, that is, the greater the number of immersions in the aqueous electrolyte polymer solution, the greater the amount of fine particles attached.

  The lower the thickness of the underlayer, that is, the lower the number of immersions in the electrolyte polymer, the higher the productivity, which is preferable. However, experience has shown that when using fine particles with weak adsorption power, the underlayer tends to be thicker. In order to increase the thickness of the undercoat layer, a method of increasing the film thickness per immersion by adjusting the hydrogen ion concentration or ionic strength of the aqueous electrolyte polymer solution is known in addition to the method of increasing the number of immersions.

  In general, the thickness of the underlayer is preferably 50 nm or less, particularly preferably 30 nm or less. The number of immersions in the positive electrolyte polymer aqueous solution and the number of immersions in the negative electrolyte polymer aqueous solution are each preferably 20 times or less, particularly preferably 10 times or less.

  As the positive electrolyte polymer, polyallylamine hydrochloride, polypyrrole, polyaniline, polyethyleneimine, polylysine, polydiallyldimethylammonium chloride, polyvinylpyridine and a copolymer containing these monomer components are preferable, and as the negative electrolyte polymer, Polyacrylic acid, polystyrene sulfonic acid, polymethacrylic acid, and copolymers containing these monomer components are preferred.

  When the underlayer is formed by such an alternate adsorption method, the adhesion strength between the underlayer and the fine particles described later is improved, and the adhesion state of the fine particles to the underlayer can be made preferable as an antireflection structure. . For example, when fine particles having a charge are used, it is recognized that the adhesion strength is improved by the interaction between the charge on the surface of the underlayer and the charge of the fine particles.

  In some cases, a polymer adsorbing layer that functions as a base layer may be formed on a substrate only by being immersed once in either the positive or negative electrolyte polymer aqueous solution. In fact, this is the most productive. In the present invention, such a single immersion is included in the alternate adsorption method for convenience.

(3) Fine particles As the fine particles (3) usable in the present invention, for example, various organic or inorganic fine particle materials can be used. In the present invention, silica fine particles, (meth) acrylic polymer fine particles, styrene polymer fine particles, styrene-butadiene polymer fine particles and the like can be preferably used. Here, “(meth) acryl” means both “acryl” and “methacryl”. Since these fine particles become a basic shape element that becomes a fine convex portion formed with the antireflection structure and prototype according to the present invention, the size and shape are determined according to the target antireflection structure and prototype. can do. When obtaining the antireflection structure and prototype according to the present invention having the same basic shape, it is preferable to use fine particles having a uniform particle size. When aiming at an antireflection structure in which two basic shapes having different sizes are mixed, relatively large particles having a uniform particle size and relatively small particles having a uniform particle size can be used in combination.

  In order to prevent multiple particles from aggregating or continuing, a repulsive force is generated between the particles, and each particle is charged for the purpose of improving the adhesion between the particles and the underlying layer. Is preferred.

(4) Heat treatment and overcoat treatment After adhering the fine particles, it is preferable to perform a heat treatment and / or an overcoat treatment on the surface to which the fine particles have adhered. As a result, the adhesion strength of the fine particles is improved, and the reverse taper shape of the skirt of the convex portion constituted by the fine particles is eliminated, and it becomes easy to manufacture a replication mold from this original mold. Heating conditions and overcoat treatment conditions can be determined in consideration of the type and content of fine particles and / or the base, adhesion strength, and the like. For example, heating conditions when using polymer fine particles as the fine particles are preferably 200 ° C. or lower, particularly 40 ° C. to 150 ° C.

  As the overcoat material used in the overcoat treatment, a polymer material, a metal chloride condensate, a metal alkoxide condensate, an alternately adsorbed film, preferably a high film thickness controllability and a throwing power (that is, an object to be adhered) Alternately adsorbing membranes having excellent properties that can be followed by a uniform surface) can be used. Such a preferable alternating adsorption film can be formed by the alternating adsorption method using, for example, the positive electrolyte polymer and the negative electrolyte polymer described above.

  In particular, the overcoat material is preferably a fluorine-based material such as a fluorine-based polymer material, a fluorine-based metal chloride condensate, or a fluorine-based alternating adsorption film. An overcoat material made of such a fluorine-based material is particularly preferable in that it can impart very good antifouling properties and peelability to the above-mentioned base material. Moreover, even if it is a two-layer type overcoat layer, such as coating a fluorine-based silane coupling agent for imparting antifouling properties and peelability onto various alternating adsorption films for eliminating the reverse taper shape good. The overcoat treatment can be performed once or a plurality of times. In particular, antifouling property, releasability and durability can be remarkably improved by performing the overcoat treatment with a fluorine material a plurality of times.

<Manufacturing method of replication mold>
The method for manufacturing a replication mold according to the present invention is a method for manufacturing a replication mold from the above-mentioned prototype, wherein the above-mentioned prototype is prepared, and using the prototype, the convex portion of the prototype is inverted and shaped. Create a negative resin mold, create a metal positive mold by a metal plating method from the resin negative mold, and further from a metal positive mold obtained in the above process, by a metal plating method, A metal negative mold is obtained as a duplication mold for duplicating the antireflection structure.

  The following shows specific examples of the method for producing a replication mold according to the present invention.

<< Overview >>
FIG. 2 shows an outline of a specific example of a preferable method for producing a replication mold according to the present invention.

  In the present invention, first, the prototype is prepared. FIG. 2 (a) shows a prototype according to the present invention.

  Next, using the prototype (P1) shown in FIG. 2 (a), a resin negative mold (N1) in which the convex portions of the prototype shown in FIG. 2 (b) are inverted and shaped is created. . In this resin negative type (N1), for example, an uncured ultraviolet curable resin is applied to the surface on which the projections of the original pattern (P1) shown in FIG. After the resin is cured by irradiation, it can be manufactured by peeling it from the original pattern (P1). For example, preferably, an uncured ultraviolet curable resin is dropped onto the surface on which the original convex portions are formed, and after dropping, an appropriate resin film, for example, polyethylene terephthalate, is adhered using a laminator such as a roller. While being spread and applied to the entire surface of the ultraviolet curable resin, after the application, the ultraviolet curable resin is cured by irradiating ultraviolet rays from the back of the film, and the cured resin together with the film is removed from the surface of the original mold (P1). Can be peeled off. On the peeled surface of the cured resin, a concave surface is formed by inverting the original convex portion. In this way, an ultraviolet curable resin is applied to the mold surface having the projections or depressions of the original mold (P1), and after covering with a film, the resin is cured by irradiating with ultraviolet rays, and the film is peeled off from the mold surface after curing. A method of copying the shape of the mold surface is referred to as a 2P method (photopolymerization method) in this specification.

  When the prototype for forming the antireflection structure is cylindrical or columnar and the antireflection structure is durable, a resinous negative mold (N1) can be created by a roll-to-roll process.

  The negative type (N1) shown in FIG. 2B can be used as it is for duplicating the optical member as it is, but this negative type (N1) is manufactured by the ultraviolet curable resin as described above. In some cases, it may not be suitable as a mass replication mold. Therefore, in such a case, a metal negative mold (N2) having a surface structure substantially the same as that of the resin negative mold (N1) is produced, and this metal negative mold (N2) is used. It is preferable to duplicate the optical member.

  This metal negative type (N2) can be manufactured by the steps as shown in FIGS. 2 (b) to 2 (d).

  A conductive thin film is formed on the surface of the resin negative type (N1) shown in FIG. 2 (b) where predetermined recesses are formed, for example, by vapor deposition, and then the thin film is plated. . Thereafter, by separating the negative mold (N1) and the plated portion, a metal positive mold (P2) in which predetermined convex portions are formed on the surface shown in FIG. 2 (c) is produced.

  Here, the conductive thin film formed in the negative type (N1) can be formed of, for example, nickel, chromium, gold, ITO, or the like, but nickel is particularly preferable in the present invention. And as plating applied on this thin film, a thing with favorable joining strength with this thin film, for example, nickel plating, is especially preferable. As a treatment method prior to plating, as described in JP-A-2002-173791, it is immersed in an alkaline degreasing solution for a short time and then subjected to electrolysis, an alkaline degreasing step, a water washing step, and an acid. An acid activation process, a drying process, a peeling film formation process, etc. can be performed.

  The positive mold (P2) shown in FIG. 2 (c) is a reproduction of the fine convex structure formed on the surface of the prototype (P1) according to the present invention as a metal.

  2A to 2B are performed a plurality of times on the same negative mold (N1), thereby producing a plurality of positive molds (P2) having substantially the same protrusion information. be able to. In such a case, even if the metal positive mold (P2) and the metal negative mold (N2) are damaged or worn and become unsuitable for use, they can be easily replaced.

  In the present invention, a metal negative mold (N2) for duplicating the antireflection structure shown in FIG. 2D is obtained from the metal positive mold (P2) by, for example, a metal plating method.

  When the metal negative mold (N2) is obtained from the metal positive mold (P2), the surface of the positive mold (P2) is used in order to facilitate separation of the positive mold (P2) and the negative mold (N2). In addition, prior to plating, a mold release process can be performed as necessary. Preferable mold release treatment includes the step of forming a release film such as an organic substance. For example, a method of depositing a fluoride material, treatment with an organic sulfur compound such as Nikkanon Tuck (registered trademark, manufactured by Nippon Chemical Industry Co., Ltd.) There are ways to do this.

  As the metal plating for producing the metal negative mold (N2), nickel plating is preferable similarly to the metal plating for producing the positive mold (P2).

  This metal negative type (N2) is used when the antireflection structure according to the present invention and the optical member having the antireflection structure are duplicated. Accordingly, it is preferable that the metal plating has sufficient strength and durability so that the fine surface structure can be reproduced well during replication. Therefore, the metal plating is preferably formed at least about 0.1 to 3 mm or more.

  When replicating the antireflection structure and the optical member having the antireflection structure according to the present invention, the optical member material can be shaped by the metal negative mold (N2). As a shaping method, a molten resin or softening resin is extruded or injected onto the surface of this metal negative mold (N2), and the molten resin or softening resin is shaped and cured under predetermined pressure and temperature conditions. be able to. It is also possible to apply an ultraviolet curable resin to the metal negative mold (N2) and cure it by ultraviolet irradiation.

  In this way, the antireflection structure according to the present invention and a large number of optical members having the antireflection structure can be duplicated.

  If, for example, the Fresnel lens shaped prototype of FIG. 1B is used as the prototype of FIG. 2A, a large number of Fresnel lenses formed with the antireflection structure according to the present invention can be duplicated.

  Thus, the antireflection structure according to the present invention can be easily manufactured from a predetermined replication mold. That is, by preparing a duplication mold capable of forming the predetermined antireflection structure, and shaping the antireflection structure with the duplication mold, a large number of optical members having the antireflection structure can be duplicated. . Therefore, according to the present invention, an optical member having a predetermined antireflection structure can be manufactured very stably, easily and at low cost.

  Furthermore, according to the present invention, it is possible to easily form a predetermined antireflection structure even on an optical substrate having a complicated surface shape.

  P1, N1, P2, and N2 shown in FIGS. 2A to 2D are all flat, but P1, N1, P2, and N2 are not necessarily flat. For example, it may be a curved surface curved with a certain curvature. In particular, when the negative type N1 and N2 are curved with a certain curvature and are cylindrical, and a negative type antireflection structure is continuously formed on the outer peripheral surface of the cylinder, this cylinder A continuous antireflection structure can be formed on the substrate surface by pressing the substrate N1 and N2 against the substrate on which the antireflection structure is to be formed and rotating the substrate surface. Such a method using cylindrical N1 and N2 is advantageous particularly when the antireflection structure of the present invention is continuously formed on a long base material. Then, a plurality of cylindrical N1 and N2 having different antireflection structures are prepared, and these are pressed against the whole surface or a part of one side or both sides of the base material on which the antireflection structure is formed to shape the base material surface. In some cases, a plurality of different antireflection structures according to the present invention can be formed on one or both sides of a single substrate.

<Optical member>
The optical member according to the present invention has the antireflection structure described above.
The optical member according to the present invention has the above-described antireflection structure on the surface, but the shape or form of the optical member itself on which the antireflection structure is formed is arbitrary. That is, the optical member according to the present invention having the above-described antireflection structure has, for example, a regular, irregular or geometric optical functional surface and / or shape, for example, a predetermined optical characteristic can be obtained. Various shapes corresponding to the target optical member, such as a Fresnel lens, a lenticular lens, a lens array, a hologram sheet, a prism, a light guide plate, light It can be any shape such as a diffusion sheet, convex lens or concave lens shape.

  Such an optical member according to the present invention can be applied to various uses, for example, display devices and solar battery panels.

  The optical member having the above-described antireflection structure is effectively prevented from reflecting light. For example, in the case of an optical member for displaying information such as a display device, its visibility is improved. In the case of such a light receiving optical member, light utilization efficiency is improved.

<Example 1>
(Preparation of prototype with antireflection structure)
Polydiallyldimethylammonium salt containing 0.1 M sodium chloride (Aldrich, trade name: PDDA) 0.4% aqueous solution and polystyrene sulfonate containing 0.1 M sodium chloride (Aldrich, (Product name: PSS) A 0.4% aqueous solution was prepared.

  The washed 5 cm square glass substrate was immersed in a PDDA solution for 2 minutes, and then thoroughly washed to form a PDDA adsorption layer on the glass substrate surface. This substrate was immersed in a PSS solution for 2 minutes, and then thoroughly washed to form a composite film (“PDDA / PSS) composite film”) in which a PDDA layer and a PSS layer were laminated in this order on the glass substrate surface. By performing this operation 6 cycles, and finally providing a PDDA adsorption layer, the PDDA layer and the PSS layer were repeatedly laminated in this order 6 times, and finally the composite film (6 layers of (PDDA / PSS) and PDDA layer) A single-layer PDDA composite film) was formed on a glass substrate.

  A polymer emulsion of carboxylated styrene / butadiene copolymer (manufactured by JSR Corporation, product name: 0693) was diluted to a solid content concentration of 24%. The composite film-formed substrate was immersed in this emulsion for 2 minutes, and then washed sufficiently to form an adsorption layer of polymer fine particles on the substrate.

  The substrate with the polymer fine particle adsorption layer formed thereon was immersed in the PDDA solution for 2 minutes and then thoroughly washed to form a PDDA adsorption layer. This substrate was immersed in a PSS solution for 2 minutes and then thoroughly washed to form a (PDDA / PSS) composite film. This cycle was repeated 5 times to form an overcoat layer (5 layers of (PDDA / PSS)) in which the PDDA layer and the PSS layer were repeatedly laminated in this order 5 times. As a result, a prototype could be produced.

(Evaluation of prototype with antireflection structure)
By measuring the transmittance, it was confirmed that it was a prototype with antireflection and antiglare properties. As a result of observing the surface with a scanning electron microscope, the basic shape of the convex portion by fine particles is randomly distributed at a density of 1933 pieces / 100 μm ² , and the maximum value, minimum value, and average value of the basic shape of the convex portion are: It was 163 nm, 109 nm, and 138 nm, respectively, and it was confirmed that the basic shapes of the convex portions of at least 10% or more were independent. Similarly, as a result of observing the cross section, it was confirmed that the reverse tapered shape of the skirt portion of the basic shape of the convex portion was eliminated. Moreover, the average height of the basic shape of the convex portion was 101 nm.

(Production of resin negative mold)
A resin-made negative mold was prepared by a 2P method (photopolymerization method) using a composition mainly composed of an acrylic photopolymerizable material with respect to the above-mentioned prototype.

(Evaluation of resin negative type)
By measuring the transmittance, it was confirmed that the transmittance of the resin negative mold was improved by 1.2% compared to the untreated resin plate. Moreover, as a result of observation with an electron microscope, it was confirmed that the resin negative mold had a recess reflecting the original pattern.

(Production of metal positive mold)
A thin layer of nickel was formed on the resin negative mold by nickel vapor deposition. This was used for nickel plating to produce a metal positive mold.

(Production of metal negative mold)
After forming a release film on the metal positive mold using an organic sulfur compound (Nikkanon Tuck (registered trademark), manufactured by Nippon Chemical Industry Co., Ltd.), nickel plating is performed, and then the plating layer is peeled off to form a metal. A metal negative mold was produced from the positive mold.

<Example 2>
(Preparation of prototype with antireflection structure)
A prototype having an antireflection structure was prepared in the same manner as in Example 1 except that the polymer emulsion was prepared to have a solid content concentration of 16%.

(Evaluation of prototype with antireflection structure)
By measuring the transmittance, it was confirmed that the prototype had antireflection ability. As a result of observation with a scanning electron microscope, the basic shape of the convex portion by the fine particles is randomly distributed at a density of 1689/100 μm ² , and the maximum value, minimum value, and average value of the basic shape of the convex portion are 163 nm, It was confirmed that the basic shapes of the protrusions of 82 nm and 140 nm were at least 10% or more were independent. Similarly, as a result of observing the cross section, it was confirmed that the reverse tapered shape of the skirt portion of the basic shape of the convex portion was eliminated. Moreover, the average height of the basic shape of the convex portion was 105 nm.

(Production of resin negative mold)
A resin-made negative mold was prepared by a 2P method (photopolymerization method) using a composition mainly composed of an acrylic photopolymerizable material with respect to the above-mentioned prototype.

(Evaluation of resin negative type)
By measuring the transmittance, it was confirmed that the transmittance of the resin negative mold was improved by 1.6% compared to the untreated resin plate. Moreover, as a result of observation with an electron microscope, it was confirmed that the resin negative mold had a recess reflecting the original pattern.

(Production of metal positive mold)
A thin layer of nickel was formed on the resin negative mold by nickel vapor deposition. This was used for nickel plating to produce a metal positive mold.

(Production of metal negative mold)
After forming a release film on the metal positive mold using an organic sulfur compound (Nikkanon Tuck (registered trademark), manufactured by Nippon Chemical Industry Co., Ltd.), nickel plating is performed, and then the plating layer is peeled off to form a metal. A metal negative mold was produced from the positive mold.

<Example 3>
(Preparation of prototype with antireflection structure)
A prototype having an antireflection structure was prepared in the same manner as in Example 1 except that a silica fine particle dispersion (catalyst chemical industry Co., Ltd., trade name: Spherica slurry 120) prepared to a solid content concentration of 18% was used. Produced.

(Evaluation of prototype with antireflection structure)
By measuring the transmittance, it was confirmed that the prototype had antireflection ability. As a result of observation with a scanning electron microscope, the basic shape of the convex portions by fine particles is randomly distributed at a density of 1822 pieces / 100 μm ² , and the maximum, minimum, and average diameters of the convex portions are 143 nm, 80 nm, and 130 nm, respectively. It was confirmed that the basic shapes of the convex portions of at least 10% or more were independent. Similarly, as a result of observing the cross section, it was confirmed that the reverse tapered shape of the skirt portion of the basic shape of the convex portion was eliminated. Moreover, the average height of the basic shape of the convex portion was 118 nm.

(Production of resin negative mold)
A resin-made negative mold was prepared by a 2P method (photopolymerization method) using a composition mainly composed of an acrylic photopolymerizable material with respect to the above-mentioned prototype.

(Evaluation of resin negative type)
By measuring the transmittance, it was confirmed that the transmittance of the resin negative mold was improved by 1.4% compared to the untreated resin plate. Moreover, as a result of observation with an electron microscope, it was confirmed that the resin negative mold had a recess reflecting the original pattern.

(Production of metal positive mold)
A thin layer of nickel was formed on the resin negative mold by nickel vapor deposition. Using this, nickel electroforming was performed to produce a metal positive mold.

(Production of metal negative mold)
After forming a release film on the metal positive mold using an organic sulfur compound (Nikkanon Tuck (registered trademark), manufactured by Nippon Chemical Industry Co., Ltd.), nickel plating is performed, and then the plating layer is peeled off to form a metal. A metal negative mold was produced from the positive mold.

<Example 4>
(Preparation of prototype with antireflection structure)
In the same manner as in Example 1, a composite film of 6 layers (PDDA / PSS) and 1 layer of PDDA was formed on a 10 cm square Fresnel lens sheet. A polymer fine particle layer was formed in the same manner as in Example 1 using the polymer emulsion having a solid content concentration of 16% used in Example 2. After the substrate was treated at 50 ° C. for 2 minutes, an overcoat layer [that is, five layers of (PDDA / PSS)] was formed in the same manner as in Example 1 to prevent reflection on the uneven surface of the Fresnel lens sheet. A prototype with structure was obtained.

(Evaluation of prototype with antireflection structure)
It was confirmed by a scanning electron microscope that the surface of the original Fresnel lens sheet had an antireflection structure with the same convexity distribution as in Example 2.

(Production of resin negative mold)
A resin-made negative mold was prepared by a 2P method (photopolymerization method) using a composition mainly composed of an acrylic photopolymerizable material with respect to the above-mentioned prototype.

(Evaluation of resin negative type)
As a result of electron microscope observation, it was confirmed that the resin negative mold had a recess reflecting the original pattern in the same manner as in Example 2.

(Production of metal positive mold)
A thin layer of nickel was formed on the resin negative mold by nickel vapor deposition. Using this, nickel electroforming was applied to produce a metal positive mold having an antireflection structure.

(Production of metal negative mold)
After forming a release film on the metal positive mold using an organic sulfur compound (Nikkanon Tuck (registered trademark), manufactured by Nippon Chemical Industry Co., Ltd.), nickel plating is performed, and then the plating layer is peeled off to form a metal. A metal negative mold was produced from the positive mold.

<Example 5>
(Preparation of prototype with antireflection structure)
A 50-inch rear projection TV Fresnel lens mold was washed with a commercially available detergent, and a composite film of 6 layers (PDDA / PSS) and 1 layer of PDDA was molded in the same manner as in Example 1. A film was formed on the surface.

  A silica fine particle dispersion (manufactured by Nissan Chemical Industries, Ltd., MP-1040) is diluted to 10%, and using this, a silica fine particle adsorption layer is formed on the surface of the film-formed mold in the same manner as in Example 1. did.

  An overcoat layer [that is, five layers of (PDDA / PSS)] was formed on the surface of the mold having the silica fine particle layer formed in the same manner as in Example 1.

  Thus, a Fresnel lens mold having fine convex portions was produced.

(Replication of lens sheet with antireflection structure)
Using the Fresnel lens mold having the fine convex portions, a Fresnel lens sheet (resin negative type) having fine concave portions was duplicated by the 2P method (photopolymerization method). At least 50 continuous copies were possible.

(Evaluation of duplicated resin negatives)
As a result of the transmittance measurement, it was found that the reflectance was reduced by about 1.6% as compared with the Fresnel lens sheet having no fine recesses. As a result of observation with a scanning electron microscope, the basic shape of the concave portions by the fine particles is randomly distributed at a density of 3866/100 μm ² , and the maximum value, the minimum value, and the average value of the diameter of the concave portions are 141 nm, 100 nm, and 121 nm, respectively. It was confirmed that the basic shape of at least 10% or more of the recesses was independent with a convex boundary. The maximum value, the minimum value, and the average value of the depth of the basic shape of the recess were 120 nm, 64 nm, and 91 nm, respectively.

(Production of metal positive mold)
A thin nickel layer was formed on the resin negative mold by electroless nickel plating. Using this, nickel electroforming was applied to produce a metal positive mold having an antireflection structure.

(Production of metal negative mold)
After forming a release film on the metal positive mold using an organic sulfur compound (Nikkanon Tuck (registered trademark), manufactured by Nippon Chemical Industry Co., Ltd.), nickel plating is performed, and then the plating layer is peeled off to form a metal. A metal negative mold was produced from the positive mold.

<Example 6>
(Preparation of prototype with antireflection structure)
Spin coated with a solution obtained by diluting a fluorine-based silane coupling agent (GE Toshiba Silicone Co., Ltd., XC98-B2472) 10-fold with isopropyl alcohol on an overcoated fine convex mold produced in the same manner as in Example 3. And heat treatment at 150 ° C. for 15 minutes. It was confirmed visually that the antireflection ability was maintained. Moreover, since the value of the water contact measured using a 1 microliter water droplet was 131 degrees, it confirmed that the fluorine-type silane coupling agent was coated.

(Production of replicas with antireflection structure)
Using the above-mentioned fine convex mold, a resin replica with a fine concave (resin negative mold) was prepared by 2P (photopolymerization method). Duplication was possible at least 100 times. As a result of transmittance measurement, it was found that the transmittance was improved by 1.3% on average.

(Production of metal positive mold)
A thin layer of nickel was formed on the resin negative mold by nickel vapor deposition. Using this, nickel electroforming was applied to produce a metal positive mold having an antireflection structure.

(Production of metal negative mold)
After forming a release film on the metal positive mold using an organic sulfur compound (Nikkanon Tuck (registered trademark), manufactured by Nippon Chemical Industry Co., Ltd.), nickel plating is performed, and then the plating layer is peeled off to form a metal. A metal negative mold was produced from the positive mold.

Sectional view of a preferred embodiment of an antireflection structure according to the present invention. The figure which shows the outline | summary of the preferable manufacturing method of the replication type | mold by this invention. Schematic diagram of basic shape of antireflection structure according to the present invention

Explanation of symbols

1 Plate 2 Base sheet 3 Fine particles

Claims (17)

An antireflection structure having an antireflection surface having fine convex portions formed on the surface,
The ratio of the convex portion occupying the antireflection surface is in a range of 10% to 90% with respect to the effective area of the antireflection surface,
The convex portion has a basic shape which may be connected to each other, and the basic shape has an average height of 30 nm to 200 nm and an average diameter of 80 nm to 400 nm, and the basic shape is substantially arranged on the antireflection surface. An antireflection structure characterized by being irregular.   The antireflection structure according to claim 1, wherein a frequency distribution of diameters of the convex portions is narrow.   The frequency distribution of the diameters of the convex portions is such that the number of convex portions having a diameter difference of 75 nm or less with respect to the convex portions having the highest frequency is 300 nm or less. The antireflection structure according to claim 2, wherein the antireflection structure is 70% or more narrow.   The antireflection structure according to claim 1, wherein a ratio of the protrusions not connected to each other with respect to the total number of the protrusions is 10% or more.   An optical member having the antireflection structure according to claim 1.   The optical member according to claim 5, comprising the antireflection structure according to claim 1 on the surface of the geometric optical functional shape.   A display device comprising the antireflection structure according to claim 1.   The display device according to claim 7, comprising the antireflection structure according to claim 1 on a surface of a geometric optical functional shape.   A solar cell panel having the antireflection structure according to claim 1.   The solar cell panel according to claim 9, which has the antireflection structure according to claim 1 on a surface of a geometric optical functional shape. A prototype for forming an antireflection structure having an antireflection surface with fine convex portions formed on the surface,
A substrate;
It consists of fine protrusions formed on the substrate,
The ratio of the convex portion occupying the antireflection surface is in the range of 10% to 90% with respect to the effective area of the antireflection surface,
The convex portion has a basic shape which may be connected to each other, and the basic shape has an average height of 30 nm to 200 nm and an average diameter of 80 nm to 400 nm, and the basic shape is substantially arranged on the antireflection surface. A prototype for forming an antireflection structure, characterized by being irregular. In producing the prototype according to claim 11,
On the surface of the substrate, if desired, an underlayer is formed using an alternate adsorption method,
Next, a method for producing a prototype for forming an antireflection structure, comprising a step of forming fine convex portions by fixing fine particles on the underlayer.   The prototype production according to claim 12, wherein the base layer is formed by the alternate adsorption method by combining a step of immersing the base material in a positive electrolyte polymer aqueous solution and a step of immersing in a negative electrolyte polymer aqueous solution. Method.   The method for producing a prototype according to claim 13, comprising a step of attaching fine particles by applying a fine particle dispersion onto the underlayer.   The method for producing a prototype according to claim 12, wherein after the fine particles are attached, a heat treatment and / or an overcoat treatment is performed on the surface to which the fine particles are attached.   The prototype manufacturing method according to claim 12, wherein the skirt of the convex portion constituted by the fine particles is not substantially reverse-tapered. A method for producing a replication mold from the prototype according to claim 11,
A prototype according to claim 11 is prepared,
Using the prototype, create a negative mold made of resin in which the convex portion of the prototype is inverted and shaped,
From the resin negative mold, create a metal positive mold by metal plating,
Furthermore, a metal negative mold as a replica mold for replicating the antireflection structure is obtained from the metal positive mold obtained in the above step by a metal plating method. .

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