JP6307830B2 - Low refractive index film and manufacturing method thereof, antireflection film and manufacturing method thereof, and coating liquid set for low refractive index film - Google Patents

Description

  The present invention relates to a low refractive index film used for an optical member and the like, a manufacturing method thereof, an antireflection film, a manufacturing method thereof, and a coating solution set for the low refractive index film.

  Low refractive index film is anti-reflection film, reflection film, semi-transmission semi-reflection film, visible light reflection infrared transmission film, infrared reflection visible light transmission film, blue reflection film, green reflection or red reflection film, bright line cut filter, color correction An optical functional film included in the film is formed on the optical member.

  Not limited to optical members with a flat surface shape, but used for optical pickup lenses, small camera lenses, projector lenses, aspheric lenses, brightness enhancement lens films for liquid crystal backlights, diffusion films, and video projection television screens. In optical functional members such as a Fresnel lens, a lenticular lens, and a microlens, a desired geometrical optical performance is obtained by the resin material having a fine structure. An optical functional film including a low refractive index film is also required on the surface of these fine structures.

  The low refractive index film is an antireflection film having a single layer structure and exhibits antireflection performance in a wider wavelength range. Furthermore, the cost of the antireflection film having a single layer structure is reduced by reducing the number of layers as compared with the antireflection film having a multilayer structure. As the refractive index of the antireflection film having a single-layer structure, a low refractive index in the range of 1.2 to 1.3 is desired when the substrate is a transparent material such as a resin material.

Examples of the method for forming the low refractive index film include vapor phase methods such as vapor deposition and sputtering, and coating methods such as dipping and spin coating.
Typical low refractive index thin films obtained by the vapor phase method are MgF _{2 with} a refractive index of 1.38 and LiF with 1.39, and the performance of these thin films as a single-layer antireflection film is low.

  In addition, as a typical material of the low refractive index film obtained by the coating method, a fluorine-based polymer material having a refractive index of 1.35 to 1.4, or fluorine having a refractive index of 1.37 to 1.46 There is a porous material in which fine particles made of a monomer polymer are fused, but a fluorine-based polymer material having a refractive index of 1.3 or less has not been obtained.

On the other hand, examples of the porous structure film obtained by baking becoming a low refractive index film include porous films of porous SOG and magnesium fluoride.
However, the porous SOG requires a baking treatment of 200 ° C. or more in order to make the refractive index 1.3 or less, and the magnesium fluoride porous film requires a heat treatment at 150 ° C. for 1 hour. Therefore, from the viewpoint of heat resistance of the resin material and maintaining the structure of the fine structure, a low refractive index film that requires firing is not suitable as an antireflection film for a resin substrate.

  Even when the solid substrate has a fine structure such as an optical pickup lens, a small camera lens, an aspheric lens, a Fresnel lens, or a lenticular lens, the low refractive index film with a single layer structure suppresses the reflected light on the lens surface. It is effective for suppressing ghost of an image projected on an image sensor or a video projection screen. Also in other optical function members, the antireflection film can increase transmitted light.

In the vapor phase method, a thin film can be formed by following the shape of the microstructure.
However, since the vapor phase method requires a vacuum apparatus, the manufacturing cost becomes expensive.
Furthermore, there is a problem that the film formed on the inner wall of the vacuum apparatus peels off and remains as a foreign substance on the low refractive index film.
Moreover, the substrate heating generally performed in order to acquire the adhesiveness of a low refractive index film | membrane produces a crack in the resin-made fine structure with a thermal stress.

The coating method does not require a vacuum device, and does not generate foreign matters derived from the vacuum device.
However, in the spin coating method, it is inevitable that the coating material remains in the concave portion of the fine structure, and the low refractive index film becomes thick in the concave portion. When the low refractive index film does not follow the fine structure in this way, geometric optical performance such as diffusibility and light condensing property provided by the fine structure is impaired.

On the other hand, in the dip coating method or the like, the film thickness can be controlled by the pulling speed, so that the coating material can follow the microstructure.
However, it is necessary to slow the pulling speed up to several tens of μm / second, and the manufacturing cost is significantly increased.

  In order to form a uniform film thickness on a concave-convex shape such as a Fresnel lens, the alkoxide solution is nebulized and calcined at a low temperature to remove the solvent. After lamination, this firing is performed to reduce the temperature difference between calcination and firing to improve film thickness measurement accuracy. There is also a method of forming.

  As a method for forming a nanometer-scale thin film from a solution, an alternate lamination method has been proposed (for example, see Non-Patent Document 1). In the alternate lamination method, since a thin film is formed by electrostatic adsorption in a liquid, it is possible to obtain a thin film that closely follows the microstructure.

  A thin film in which an electrolyte polymer having a positive charge and an electrolyte polymer having a negative charge are alternately laminated is a low refractive index film having a refractive index of about 1.2 by generating voids in the thin film by hydrochloric acid treatment (for example, Patent Documents 1 and 2).

  On the other hand, a fine particle monolayer film in which fine particles are electrostatically adsorbed on an electrolyte polymer layer becomes a low refractive index film without the need for acid treatment or the like (see, for example, Patent Documents 3 and 4). The reason why the fine particle single layer film is a low refractive index film is that the surface irregularity shape by fine particles having a diameter of 100 nm or more continuously changes the refractive index, and voids between the fine particles lower the average refractive index.

However, a fine particle monolayer film using fine particles having a diameter exceeding 100 nm scatters and diffuses visible light, and thus is not suitable for an optical member that requires transparency.
In addition, when the optical member surface has a fine structure, for example, when the fine structure is a lens, when the low refractive index film on the lens surface scatters or diffuses light, the geometrical optical means that the light does not collect at the focal point. Cause a significant decrease in performance.

On the other hand, when fine particles having a diameter of 100 nm or less are used, a transparent fine particle laminated film is easily obtained.
However, the refractive index reduction effect derived from the surface irregularity shape cannot be obtained. For this reason, it has been attempted to reduce the average refractive index of the fine particle multilayer film by increasing the density of voids between the fine particles (see, for example, Patent Documents 5 to 7).

  The fine particle laminated film on these optical members must have substrate adhesion and film strength. This is because the required properties cannot be obtained if scratches or peeling occur during processing, transportation, assembly, or storage of optical components with a fine particle layered film. It is. Further, when the optical member is in the form of a sheet such as a Fresnel lens, durability to an adhesive tape used for surface protection, contamination prevention, and fixing during processing, transportation, assembly, and storage is required.

On the other hand, as a low refractive index thin film formed on the optical surface of the substrate, a MgF ₂ fine particle film formed by a wet process is impregnated in a silicon alkoxide or polysilazane solution, and a silicon oxide binder is interposed between the surface of the MgF ₂ fine particles and the fine particles. A low-refractive-index film having excellent mechanical resistance and adhesion to the substrate, and having excellent environmental resistance, by bringing the silicon oxide binder into contact with the precursor and firing, thereby bonding the silicon oxide binder to the fine particles and the substrate. Has been proposed (see, for example, Patent Document 8).

  However, in the conventional wet process, it is difficult to form a low-refractive-index film in which fine particles have a porous structure with a good followability with respect to an optical fine structure and a uniform film thickness, In order to obtain the mechanical strength of the film, when impregnating a binder such as silicon alkoxide between the fine particles or between the fine particles and the substrate, the unevenness of the impregnation, particularly the liquid accumulation in the concave shape portion, Thickness, refractive index, and mechanical strength were non-uniform.

  As a method of forming a uniform film thickness with good followability with respect to an optical member, and the formed low refractive index film has substrate adhesion, an alkoxysilane is formed on a fine particle laminated film formed by using an alternating lamination method. There has been proposed a method of bonding an optical member, microparticles, and microparticles by contacting a silicon compound solution using a material (see, for example, Patent Document 9).

  However, in the silicon compound solution using alkoxysilane, the performance of the solution changes due to the mixing of moisture in the solution, and the adhesion improving effect becomes unstable. When water is contained in the solution for forming the fine particle laminated film, the risk of water being mixed into the silicon compound solution is increased by carrying out processing with the equipment of one line. In particular, when processing optical components such as optical pickup lenses and small camera lenses set on trays, Fresnel lenses and microlenses with complex shapes, mixing of moisture after the formation of the fine particle laminate film In order to avoid this, it is necessary to take measures such as drying for a long time, separating the formation process of the fine particle laminated film and the contact process with the silicon compound solution, frequently changing the silicon compound solution, Manufacturing costs increase due to reduced throughput, increased manufacturing equipment costs, and increased material costs.

Further, when the dip coating method is used (in order to form a low refractive index film on both surfaces of the optical member), in order to maintain followability to the optical member, pulling up from the silicon compound solution using alkoxysilane It is necessary to reduce the speed from several mm / second to several hundred μm / second, which increases the manufacturing cost.
Further, when handling a silicon compound solution using alkoxysilane, it is necessary to handle and control the explosion-proof of the equipment.

JP 2004-109624 A JP 2005-266252 A JP 2002-006108 A JP 2006-208726 A JP 2006-297680 A JP 2006-301124 A JP 2006-301125 A International Publication No. 2006/030848 JP 2013-7831 A

Thin Solid Films, 210/211, p831 (1992)

The present invention has been made in view of the above-described conventional problems, and its problem is that it has excellent adhesion to a solid substrate and follows the fine structure of a solid substrate having a fine structure. An object of the present invention is to provide a low refractive index film that does not impair geometric optical performance such as diffusibility and light condensing property, and a method for manufacturing the same.
It is another object of the present invention to provide an antireflection film capable of making reflected light and transmitted light achromatic in addition to suppressing reflected light and improving transmitted light, and a method for manufacturing the same.
Furthermore, an object of the present invention is to provide a coating solution set for a low refractive index film for forming the low refractive index film.

The present invention for solving the above problems is as follows.
(1) A polycation solution and a silicon compound solution are alternately brought into contact with a fine particle laminated film formed by alternately adsorbing an electrolyte polymer and fine particles on the surface of a solid substrate having a fine structure on the surface, A low refractive index film obtained by bonding the fine particles and the fine particles,
The silicon compound solution includes a water-soluble silicate represented by a general formula M ₂ O · nSiO ₂ (n = 0.5 to 8, M represents an alkali metal of Li, Na, or K). Low refractive index film.

(2) The solid substrate is an optical pickup lens, a small camera lens, a projector lens, an aspherical lens, a lenticular lens, a Fresnel lens, a prism, a microlens array, a light guiding microstructure, a light diffusing microstructure. And the low refractive index film according to the above (1), which has a fine structure on the surface for obtaining any one selected from the group consisting of holograms.

(3) The low level according to (1) or (2) above, wherein the fine particles in the fine particle laminated film include one or more of porous silica fine particles, hollow silica fine particles, and silica fine particles having a shape in which primary particles are connected. Refractive index film.

(4) The low refractive index film according to any one of (1) to (3), wherein an average primary particle diameter of the fine particles in the fine particle laminated film is 1 nm to 100 nm.

(5) An antireflection film including the low refractive index film according to any one of (1) to (4).

(6) A method for producing a low refractive index film formed on the surface of a solid substrate having a microstructure on the surface,
(I) contacting the polycation solution with the surface of the solid substrate, and then rinsing;
(Ii) a step of bringing a dispersion of fine particles having a negative charge into contact with the surface of the solid substrate after (i), followed by a rinsing step;
(Iii) a step of alternately repeating (i) and (ii) to form a fine particle laminated film;
(Iv) a step of bringing a polycation solution into contact with the fine particle laminated film, followed by a rinsing step;
(V) In the fine-particle laminated film after (iv), a water solution represented by the general formula M ₂ O.nSiO ₂ (n = 0.5 to 8, M represents an alkali metal of Li, Na, or K) A step of bringing a silicon compound solution containing a functional silicate into contact, followed by a rinsing step, and (vi) repeating (iv) and (v) above alternately to form a polycation and silicon in the polycation solution on the fine particle laminate film Adsorbing water-soluble silicate in the compound solution;
A method for producing a low refractive index film, comprising:

(7) A method for producing a low refractive index film formed on the surface of a solid substrate having a microstructure on the surface,
(I) contacting the polycation solution with the surface of the solid substrate, and then rinsing;
(Ii) contacting the surface of the solid substrate after (i) with a polyanion solution, followed by rinsing;
(Iii) a step of bringing a dispersion of fine particles having a positive charge into contact with the surface of the solid substrate after (ii), followed by a rinsing step;
(Iv) a step of alternately repeating (ii) and (iii) to form a fine particle laminated film;
(V) a step of bringing a polyanion solution into contact with the fine particle laminated film, followed by a rinsing step;
(Vi) contacting the polycation solution with the fine particle layered film after (v), and then rinsing;
(Vii) In the fine particle laminated film after the above (vi), a water solution represented by the general formula M ₂ O.nSiO ₂ (n = 0.5 to 8, M represents an alkali metal of Li, Na, or K) A step of contacting a silicon compound solution containing a functional silicate, a step of rinsing, and (viii) the steps (vi) and (vii) are alternately repeated to form a polycation and silicon in the polycation solution on the fine particle laminated film. Adsorbing water-soluble silicate in the compound solution;
A method for producing a low refractive index film, comprising:

(8) The heat treatment is performed after the step of adsorbing the polycation in the polycation solution and the water-soluble silicate in the silicon compound solution to the fine particle laminated film (6) or (7) A method for producing a low refractive index film as described in 1.

(9) The solid substrate is an optical pickup lens, a small camera lens, a projector lens, an aspherical lens, a lenticular lens, a Fresnel lens, a prism, a microlens array, a light guiding microstructure, a light diffusing microstructure. And the method for producing a low refractive index film according to any one of (6) to (8), wherein the surface has a fine structure for obtaining any one selected from the group consisting of holograms.

(10) The method for producing a low refractive index film according to any one of (6) to (9), wherein the solid substrate is a plastic substrate having a thermal expansion coefficient of 50 to 350 (ppm / K).

(11) Any of the above (6) to (10), wherein the fine particles of the fine particle dispersion are fine particles containing at least one of porous silica fine particles, hollow silica fine particles and silica fine particles having a shape in which primary particles are connected. A method for producing a low refractive index film according to claim 1.

(12) The method for producing a low refractive index film according to any one of (6) to (11), wherein an average primary particle diameter of the fine particles of the fine particle dispersion is 1 nm or more and 100 nm or less.

(13) A method for producing an antireflection film comprising the method for producing a low refractive index film according to any one of (6) to (12).

(14) A coating solution set for a low refractive index film comprising an electrolyte polymer solution, a fine particle dispersion, a polycation solution and a silicon compound solution,
The charge of the electrolyte polymer in the electrolyte polymer solution is opposite to the charge of the fine particles in the fine particle dispersion,
The silicon compound solution is general formula _{M 2 O · nSiO 2 (n} = 0.5 ~8, M is Li, Na, or K represents an alkali metal) and comprising a water-soluble silicate represented by Coating solution set for low refractive index film.

(15) The low refractive index film according to (14), wherein the fine particles in the fine particle dispersion include one or more of porous silica fine particles, hollow silica fine particles, and silica fine particles having a shape in which primary particles are connected. Coating liquid set.

(16) The coating liquid set for a low refractive index film as described in (14) or (15) above, wherein the average primary particle diameter of the fine particles of the fine particle dispersion is 1 nm or more and 100 nm or less.

(17) The coating solution set for a low refractive index film according to any one of (14) to (16), wherein the concentration of the fine particles in the fine particle dispersion is 0.005% by mass to 15% by mass.

(18) The ionic group in the electrolyte polymer solution or the polycation solution is selected from the group consisting of a primary, secondary or tertiary amino group, a salt of the amino group, and a quaternary ammonium type group The coating liquid set for a low refractive index film according to any one of the above (14) to (17).

(19) The electrolyte polymer solution in the electrolyte polymer solution or the polycation solution in the polycation solution has a concentration of 0.0003 mass% or more and 3 mass% or less in any one of the above (14) to (18) The coating liquid set for low refractive index films | membranes of description.

According to the present invention, it has excellent adhesion to a solid substrate, follows the microstructure of a solid substrate having a fine structure, and impairs geometric optical performance such as diffusibility and light condensing property that the fine structure brings. It is possible to provide a low refractive index film and a method for manufacturing the same.
Moreover, according to this invention, in addition to suppression of reflected light and improvement of transmitted light, it is possible to provide an antireflection film that can make reflected light and transmitted light achromatic, and a method for manufacturing the same.
Furthermore, according to this invention, the coating liquid set for low refractive index films | membranes for forming the said low refractive index film | membrane can be provided.

It is the conceptual diagram which showed a mode that electrolyte polymer and microparticles | fine-particles were laminated | stacked alternately, and a fine particle laminated film was formed. It is the conceptual diagram which showed the mode of the coupling | bonding between microparticles | fine-particles accompanying application | coating of a silicon compound. It is a schematic diagram which shows the state of the microparticles which continued in the shape of a bead, and the particle diameter of a primary particle. It is a graph which shows the relationship between the refractive index of an antireflection film, and the surface reflectance of a solid base material (refractive index 1.54) with an antireflection film. FIG. 2A is a diagram schematically illustrating a part of a cross section of a concave portion of a Fresnel lens in which a low refractive index film is formed in Example 1, and FIG. It is the figure (A) which shows typically a part of cross section for the recessed part of the Fresnel lens which formed the low refractive index film | membrane in the comparative example 3, and the figure (B) which expanded a part of (A).

The low-refractive index film of the present invention is obtained by alternately contacting a polycation solution and a silicon compound solution with a fine particle laminated film formed by alternately adsorbing an electrolyte polymer and fine particles on the surface of a solid substrate having a fine structure on the surface. The low refractive index film formed by bonding the solid substrate, the fine particles, and the fine particles, wherein the silicon compound solution has a general formula M ₂ O · nSiO ₂ (n = 0.5-8, M Represents an alkali metal of Li, Na, or K).
The antireflection film of the present invention includes the low refractive index film of the present invention.

The method for producing a low refractive index film according to the first aspect of the present invention is a method for producing a low refractive index film formed on the surface of a solid substrate having a microstructure on its surface,
(I) contacting the polycation solution with the surface of the solid substrate, and then rinsing;
(Ii) a step of bringing a dispersion of fine particles having a negative charge into contact with the surface of the solid substrate after (i), followed by a rinsing step;
(Iii) a step of alternately repeating (i) and (ii) to form a fine particle laminated film;
(Iv) a step of bringing a polycation solution into contact with the fine particle laminated film, followed by a rinsing step;
(V) In the fine-particle laminated film after (iv), a water solution represented by the general formula M ₂ O.nSiO ₂ (n = 0.5 to 8, M represents an alkali metal of Li, Na, or K) A step of bringing a silicon compound solution containing a functional silicate into contact, followed by a rinsing step, and (vi) repeating (iv) and (v) above alternately to form a polycation and silicon in the polycation solution on the fine particle laminate film Adsorbing water-soluble silicate in the compound solution;
It is characterized by including.

The method for producing a low refractive index film according to the second aspect of the present invention is a method for producing a low refractive index film formed on the surface of a solid substrate having a microstructure on the surface,
(I) contacting the polycation solution with the surface of the solid substrate, and then rinsing;
(Ii) contacting the surface of the solid substrate after (i) with a polyanion solution, followed by rinsing;
(Iii) a step of bringing a dispersion of fine particles having a positive charge into contact with the surface of the solid substrate after (ii), followed by a rinsing step;
(Iv) a step of alternately repeating (ii) and (iii) to form a fine particle laminated film;
(V) a step of bringing a polyanion solution into contact with the fine particle laminated film, followed by a rinsing step;
(Vi) contacting the polycation solution with the fine particle layered film after (v), and then rinsing;
(Vii) In the fine particle laminated film after the above (vi), a water solution represented by the general formula M ₂ O.nSiO ₂ (n = 0.5 to 8, M represents an alkali metal of Li, Na, or K) A step of contacting a silicon compound solution containing a functional silicate, a step of rinsing, and (viii) the steps (vi) and (vii) are alternately repeated to form a polycation and silicon in the polycation solution on the fine particle laminated film. Adsorbing water-soluble silicate in the compound solution;
It is characterized by including.
The method for producing an antireflection film of the present invention includes the method for producing a low refractive index film of the present invention.

Furthermore, the coating liquid set for a low refractive index film of the present invention is a coating liquid set for a low refractive index film comprising an electrolyte polymer solution, a fine particle dispersion, a polycation solution, and a silicon compound solution, The charge of the electrolyte polymer is opposite to the charge of the fine particles in the fine particle dispersion, and the silicon compound solution has the general formula M ₂ O · nSiO ₂ (n = 0.5 to 8, M is Li , Na or K represents an alkali metal).
Hereinafter, embodiments of the low refractive index film and the manufacturing method thereof, the antireflection film and the manufacturing method thereof, and the coating solution set for the low refractive index film of the present invention will be described.

  The low refractive index film of the present invention is formed on a solid substrate such as an optical member, so that it is an antireflection film, a reflection film, a semi-transmission semi-reflection film, a visible light reflection infrared transmission film, an infrared reflection visible light transmission film, a blue reflection. It functions as an optical functional film included in the film, the green reflection or red reflection film, the bright line cut filter, and the color tone correction film.

  In addition, for microscopic structures having geometric optical performance such as optical function members such as brightness enhancement lens films and diffusion films for liquid crystal backlights, Fresnel lenses, lenticular lenses, and microlenses used in video projection television screens. However, the low refractive index film of the present invention follows well. As a result, the low refractive index film of the present invention functions as an optical functional film without impairing the geometric optical performance of the fine structure.

(A) Solid substrate The solid substrate may be flat or have other shapes. The shape has a fine structure on the surface and is a fine structure having geometric optical performance. Optical pickup lens, small camera lens, projector lens, aspheric lens, lenticular lens sheet, Fresnel lens sheet, prism sheet, micro lens array sheet, on-chip micro lens array, light guide sheet, diffusion sheet, hologram sheet, Examples include solar cells and LED bulb covers.

  Examples of microstructures include optical pickup lenses, small camera lenses, aspheric lenses, lenticular lenses, Fresnel lenses, prisms, microlens arrays, light guiding microstructures, light diffusing microstructures, and holograms. Examples include a fine structure.

(B) Solid substrate material In order to form a fine particle laminate film on a solid substrate by an alternate lamination method, the solid substrate needs to have a charge on its surface. In order for the fine particle laminated film formed using the alternating lamination method to adhere to the solid substrate, it is desirable that a polar group having a charge exists on the surface of the solid substrate. The polar group has a positive or negative charge locally because it has a charge bias (intramolecular polarization) in the molecule or becomes an ion by dissociation.

  A substance having a charge opposite to that of the polar group is adsorbed. As the polar group, vinyl group, epoxy group, styryl group, methacryloxy group, acryloxy group, amino group, ureido group, chloropropyl group, mercapto group, sulfide group, sulfonic acid group, phosphoric acid group, isocyanate group, carboxyl group, It is desirable that it is one or more of functional groups such as an ester group, a carbonyl group, a hydroxyl group, and a silanol group.

  As a result of the solid surface having a polar group on the surface, the absolute value of the zeta potential is preferably 1 to 100 mV, more preferably 5 to 90 mV, and even more preferably 10 to 80 mV.

Examples of the material of the solid substrate include semiconductors such as plastic and silicon, metals, inorganic compounds, and the like.
Moreover, the shape is arbitrary, such as a shape which has a film, a sheet | seat, a board, and a curved surface. If the solid substrate can be partly or wholly immersed, such as a cylinder, thread, fiber, foam, etc., and the solution can enter, it can be used because a fine particle laminated film is formed on the surface. it can.

In the present invention, the fine particle multilayer film can be formed following the surface structure even with respect to the irregular shape of the cross section of the solid substrate.
Furthermore, in the present invention, even if the surface of the solid substrate has a nanometer-scale or sub-micron-scale structure, the fine particle laminated film can be formed following the structure.

  As described above, in the present invention, the fine particle laminated film is formed following the structure of the fine structure by the alternating lamination method (details will be described later), and further, the silicon is formed on the fine particle laminated film by the alternating lamination method. Since the compound is adsorbed, the obtained low-refractive-index film also follows the fine structure, and does not impair the geometric optical performance such as diffusibility and light condensing property provided by the fine structure.

  Examples of the plastic include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, which have a hydroxyl group or a carboxyl group, a polyamide having a carboxyl group or an amino group, a polyvinyl alcohol, a polymer of acrylic acid or methacrylic acid, or A copolymer etc. are mentioned.

  Also, polyethylene, polypropylene, polystyrene, triacetyl cellulose, diacetyl cellulose, acetate butyrate cellulose, polyethersulfone, polyimide, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polymethyl methacrylate, polycarbonate, polyurethane, etc. are used. You can also.

  The material of the plastic substrate used in the present invention is 50 to 350 (ppm / K), preferably 60 to 300 (ppm / K) from the viewpoint of dimensional stability in the use environment, particularly the shape stability at the use temperature. ), More preferably 60-200 (ppm / K). When the thermal expansion coefficient is 50 to 350 (ppm / K), it is excellent in moldability as a plastic base material, and the degree of deformation due to heat is small. The distance for image formation does not change.

On the other hand, examples of the metal include iron, copper, white copper, tinplate, and the like, which are subjected to a treatment such as forming an oxide film so that electric charges exist on the surface.
Examples of the inorganic compound include glass and ceramics, and have a polar group on the surface.

  The surface of the solid substrate may be subjected to corona discharge treatment, glow discharge treatment, plasma treatment, ultraviolet irradiation, ozone treatment, chemical etching treatment with alkali or acid, etc. to introduce polar groups. You may use resin which introduce | transduced the polar group by such a process.

  In the present invention, the solid substrate includes those in which a resin film, an inorganic film, or a film containing both an organic material and an inorganic material is laminated on the substrate. These resin film layer, inorganic film layer, and organic-inorganic film may be located anywhere on the solid base material, and need not have a polar group when not located on the outermost surface of the solid base material.

  These resin film layer, inorganic film layer, or organic-inorganic film may or may not have a function of improving the optical function and mechanical properties of the solid substrate. An example of a layer that improves the mechanical properties of the solid substrate is a hard coat layer.

  Examples of films for imparting optical functions include antireflection films, reflective films, semi-transmissive and semi-reflective films, visible light reflective infrared transmissive films, infrared reflective visible light transmissive films, blue reflective films, green reflective films, and red reflective films. Examples thereof include an optical functional film including one or more films, bright line cut filters, and color tone correction films. Further optical functions can be imparted by forming a low refractive index film on a solid substrate having these optical function films.

  For example, when a low refractive index film is formed on a solid substrate having one or more of an antireflection function, a bright line cut filter function, a near infrared cut filter function, and a color tone correction function, the antireflection function and the bright line cut filter are formed. Among functions, near-infrared cut filter function, and color tone correction function, one or more functions not found in solid substrates can be added, and it is suitable for optical filters for displays such as plasma display panels and liquid crystal display devices. An optical member can be obtained.

  An optical filter obtained by forming an antireflection film including a low refractive index film using an optical film such as a light guide plate, a diffusion film, a prism film, a brightness enhancement film, and a polarizing plate as a solid substrate is an optical film. Reflection at the interface is suppressed. For this reason, the brightness of a liquid crystal display device incorporating such an optical filter is improved.

  In addition, in a lens obtained by forming an antireflection film including a low refractive index film using a small camera lens as a fixed base material, reflection at the lens interface is suppressed. For this reason, a ghost and flare can be improved.

  In addition, a transflective liquid crystal display device incorporating an optical filter obtained by using a light diffusing film as a solid substrate and forming a transflective film layer including a low refractive index film on the solid substrate is not provided. Brightness due to light reflection is improved. As described above, by forming a fine particle laminated film on a filter member for a display such as a flat panel display, it is possible to achieve high functionality of those members.

  In addition, it is possible to prevent contact between the solid substrate and the fine particle dispersion, such as by sticking an adhesive film on the front or back surface of a solid substrate where formation of a low refractive index film is not desired. Formation of the film can be prevented.

(C) Hard coat material By laminating a hard coat film, the mechanical properties of the solid substrate are improved. Examples of materials for the hard coat film include cross-linked products of polymerizable unsaturated double bond-containing compounds such as acrylic resins, urethane resins, and melamine resins, organic silicate compounds, silicone resins, and metal oxides. It is done. As the polymerizable unsaturated double bond-containing compound, a curable resin such as a thermosetting resin or a radiation curable resin can be used, and it is particularly preferable to use a polyfunctional polymerizable unsaturated double bond-containing compound. .

  Examples of the polyfunctional polymerizable unsaturated double bond-containing compound include esters of polyhydric alcohol and methacrylic acid or acrylic acid (eg, ethylene glycol di- (meth) acrylate, 1,4-cyclohexane diacrylate, pentaerythritol tetra- (Meth) acrylate, pentaerythritol tri- (meth) acrylate, trimethylolpropane tri- (meth) acrylate, trimethylolethane tri- (meth) acrylate, dipentaerythritol tetra- (meth) acrylate, dipentaerythritol penta- ( (Meth) acrylate, dipentaerythritol hexa- (meth) acrylate, 1,3,5-cyclohexanetriol trimethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinyl base Zen derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone compounds (eg, divinylsulfone), acrylamide compounds (eg, methylenebis) Acrylamide) and methacrylamide, but are not limited thereto. In the above, (meth) acrylate means "methacrylate or acrylate".

  Examples of commercially available polyfunctional polymerizable unsaturated double bond-containing compounds include polyfunctional acrylic cured paints (Diabeam series, etc.) manufactured by Mitsubishi Rayon Co., Ltd., and polyfunctional acrylics manufactured by Nagase Sangyo Co., Ltd. -Based cured paint (Denacol series, etc.), Shin-Nakamura Chemical Co., Ltd. polyfunctional acrylic cured paint (NK ester series, etc.), Dainippon Ink & Chemicals Co., Ltd. multifunctional acrylic cured paint (UNIDIC) Series), multifunctional acrylic cured paints made by Toa Gosei Chemical Industry Co., Ltd. (Aronix series, etc.), multifunctional acrylic cured paints made by NOF Corporation (Blenmer series, etc.), Nippon Kayaku ( Co., Ltd. polyfunctional acrylic curable paint (KAYARAD series, etc.), Kyoeisha Chemical Co., Ltd. polyfunctional acrylic curable paint (light ester series, Ito acrylate series, etc.).

  It is particularly effective to add a polymerization initiator for the purpose of efficiently initiating the polymerization of these polyfunctional polymerizable unsaturated double bond-containing compounds. As the polymerization initiator, acetophenones, benzophenones, Michler's benzoyl are used. Benzoates, α-amyloxime esters, tetramethylthiuram monosulfide and thioxanthones are preferred.

In addition to a polymerization initiator, a sensitizer may be used for the purpose of promoting polymerization.
Furthermore, a leveling agent and a filler may be added, and additives are added to these compounds as necessary to form a coating material.

  The coating material is coated using, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc. to form a coating film, and after drying, a thermosetting resin composition When using a product, the coating is cured by heating. When using an ionizing radiation curable resin composition, the coating is cured by irradiating with ionizing radiation. A layer may be formed.

  Examples of the ionizing radiation include radiation, electron beams, particle beams, gamma rays, ultraviolet rays, and the like, and ultraviolet rays are particularly preferable. The light source can be from near ultraviolet rays using a mercury lamp to vacuum ultraviolet rays using an excimer laser.

  A commercial product of a solid substrate formed with a hard coat film may be used, and as such a commercial product, hard coat PET (KB film) manufactured by Kimoto, hard coat PET manufactured by Toray (Tough Top N-TOP) Examples thereof include a hard coat film made by Toyo Packaging Co., Ltd., and a hard coat polycarbonate (Lexan Margard, Lexan CTG AF) made by Nisshin Kasei.

(D) Intermediate layer In order to reliably introduce a polar group into a solid substrate, an intermediate layer can be laminated on the solid substrate to form a solid substrate. In this case, the intermediate layer is a surface layer of the solid substrate. Alternatively, the intermediate layer material may form a fine structure.

  The intermediate layer is provided between the solid base material and the fine particle laminated film, and the intermediate layer has a polar group to improve the adhesion between the solid base material and the fine particle laminated film. It is considered that the surface hardness of the fine particle laminated film on the solid substrate is improved because the fine particle laminated film is firmly bonded to the solid substrate through the intermediate layer.

The polar group contained in the intermediate layer is vinyl group, epoxy group, styryl group, methacryloxy group, acryloxy group, amino group, ureido group, chloropropyl group, mercapto group, sulfide group, sulfonic acid group, phosphoric acid group, isocyanate group. , A carboxyl group, an ester group, a carbonyl group, a hydroxyl group, or a silanol group, preferably one or more functional groups.
As the material for the intermediate layer, resins having these groups, silane coupling agents, and the like can be used.

  Examples of the resin as the material for the intermediate layer include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, which have a hydroxyl group or a carboxyl group, a polyamide having a carboxyl group or an amino group, polyvinyl alcohol, acrylic acid, or methacrylic acid. There are acid polymers or copolymers.

  The lamination of the intermediate layer on the solid substrate is, for example, a method of applying a coating solution obtained by dissolving a resin having a polar group in a solvent and drying the solid substrate, and a raw material for the resin constituting the intermediate layer. Monomers and oligomers (including monomers and oligomers having polar groups) are applied to a solid substrate and reacted and cured. A silane coupling agent is mixed with the raw material monomers and oligomers of the resin as the intermediate layer. It can be performed by a method such as coating and reaction curing. In addition to the method for forming the intermediate layer described above, the intermediate layer material may be used as a solid substrate, for example, by transferring the intermediate layer material to a mold.

You may manufacture the coating liquid of the polyester-type resin to which the polar group was provided as follows.
117 parts of dimethyl terephthalate, 117 parts of dimethyl isophthalate, 103 parts of ethylene glycol, 58 parts of diethylene glycol, 0.08 part of zinc acetate and 0.08 part of antimony trioxide were heated to 40-220 ° C. in a reaction vessel, and 3 Transesterification is performed for a time to obtain a polyester-forming component.

  Next, 9 parts of 5-sodium sulfoisophthalic acid was added, and the esterification reaction was carried out at 220 to 260 ° C. for 1 hour, followed by a polycondensation reaction under reduced pressure (10 to 0.2 mmHg) for 2 hours. A polyester copolymer having a sulfonic acid group having a point of 140 ° C. is obtained.

300 parts of the polyester copolymer provided with the sulfonic acid group and 140 parts of n-butyl cellosolve are stirred at 150 to 170 ° C. for 3 hours to obtain a uniform viscous melt, and 560 parts of water is gradually added to the melt. It can be added to obtain a polyester resin aqueous dispersion.
A commercially available water-dispersed polyester resin to which a sulfonic acid is added (for example, Vylonal MD-1200, manufactured by Toyobo Co., Ltd., trade name) may be used.

  In the above procedure, a metal salt such as sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid and their ester-forming derivatives may be used instead of 5-sodium sulfoisophthalic acid. A polyester copolymer provided with an acid group can be obtained.

Examples of the metal in the metal salt include sodium, lithium, potassium, magnesium and the like.
Moreover, the polyester copolymer provided with the amino group can be obtained by using 5-aminoisophthalic acid or the like instead of 5-sodium sulfoisophthalic acid.

You may manufacture the polyurethane-type resin to which the polar group was provided as follows.
192 parts of polyether containing sodium sulfonate obtained by sulfonation of polyether of ethylene oxide starting from allyl alcohol with sodium metabisulfite (SO3 content: 8.3% by mass, polyethylene oxide content: 83% by mass), polytetramethylene 1013 parts adipate and 248 parts polypropylene oxide polyether initiated with bisphenol A were mixed and dehydrated under reduced pressure (10-0.2 mmHg) at 100 ° C. to 70 ° C., to which 178 parts isophorone diisocyanate and hexahexa A mixture with 244 parts of methylene-1,6-diisocyanate is added and the resulting mixture is further stirred in the range of 80 ° C. to 90 ° C. until the isocyanate content is 5.6% by weight.

The resulting prepolymer is cooled to 60 ° C., and 56 parts of biuret polyisocyanate obtained from 3 moles of hexamethylene diisocyanate and 1 mole of water, and 173 parts of bisketimine obtained from isophoronediamine and acetone are successively added.
Next, a 50 ° C. aqueous solution in which 15 parts of hydrazine hydrate is dissolved can be added to this mixture with vigorous stirring to obtain an aqueous polyurethane resin dispersion.

  Examples of the resin prepared so that the functional group is imparted include organic solvent-soluble amorphous polyester resins, and as commercially available products, Toyobo Co., Ltd., Byron (103, 200, 220, 226, 240, 245, 270, 280, 290, 296, 300, 500, 516, 530, 550, 560, 600, 630, 650, 660, 670, 885, GK110, GK130, GK140, GK150, GK180, GK190, GK250, GK330, GK360, GK590, GK640, GK680, GK780, GK810, GK880, GK890, BX1001, trade names).

  Moreover, water-dispersed polyester resin is mentioned, As a commercial item, Toyobo Co., Ltd. product, Bironal (MD-1100, MD-1200, MD-1220, MD-1245, MD-1250, MD-1335, MD -1400, MD-1480, MD-1500, MD-1930, MD-1985, trade names).

  Moreover, a polyester urethane resin is mentioned, As a commercial item, the product made by Toyobo Co., Ltd., Byron (UR-1350, UR-1400, UR-2300, UR-3200, UR-3210, UR-3500, UR -4125, UR-5537, UR-8200, UR-8300, UR-8700, UR-9500, trade names).

  In the present invention, examples of the silane coupling agent include those represented by the following chemical formula (I).

(In the formula, R ¹ is a non-hydrolyzable group, which is a vinylalkyl group, an epoxyalkyl group, a styrylalkyl group, a methacryloxyalkyl group, an acryloxyalkyl group, an aminoalkyl group, a ureidoalkyl group, a chloropropyl group, A halogen alkyl group such as an alkyl group or a sulfide alkyl group, a mercaptoalkyl group, an isocyanate alkyl group or a hydroxyalkyl group, R ² is a hydrolyzable group having 1 to 6 carbon atoms, and n is 1 to 1 3 of an integer, when R ¹ are a plurality, each R ¹ may be the being the same or different, when OR ² is more, even if each OR ² is not being the same or different Good.)

  As an example of a silane coupling agent treatment of a solid substrate, first, a silane coupling agent is hydrolyzed to an silanol group by hydrolyzing an alkoxy group in an aqueous medium in the presence or absence of an acid. By bringing the solid substrate into contact with the solution, silanol groups can be adsorbed by hydrogen bonding to the hydroxyl groups present on the surface of the solid substrate, and then the solid substrate can be dried, thereby performing dehydration condensation. A reaction takes place and a non-hydrolyzable group can be imparted to the surface of the solid substrate.

  The silanol group that has not reacted with the non-hydrolyzable group also functions as a polar group in the present invention, and the solid substrate and the fine particle laminated film can be adhered by interacting with the fine particle laminated film. Although details are not clear, it is considered that one or more of covalent bonds, intermolecular forces, and van der Waals forces contribute to the interaction.

  Specific examples of the silane coupling agent include vinyl trichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylphenyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, and other vinyl group functional silanes, Alkyl group or aryl group functional silane such as methoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltri Epoxy functional groups such as methoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldiisopropenoxysilane, methyltriglycidoxysilane, γ-glycidoxypropyltriethoxysilane Functional silane, styryl group functional silane such as p-styryltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, methyltri (methacryloxyethoxy) silane, γ-methacryloxypropylmethyldi Methacryloxy group functional silanes such as ethoxysilane, γ-methacryloxypropyltriethoxysilane, acryloxy group functional silanes such as γ-acryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane , Γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopro Rumethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N-β- (N-vinylbenzylamino) Ethyl) -γ-aminopropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, γ-triethoxysilyl-N- (1,3-dimethyl-butylidene) -propylamine, N-phenyl-3-aminopropyltri Amino group functional silane such as methoxysilane, ureido group functional silane such as γ-ureidopropyltriethoxysilane, chloropropyl group functional silane such as γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ -Mercaptopropyltriethoxysilane, γ-mercaptopropi Mercapto group functional silane such as methyldimethoxysilane, sulfide group functional silane such as bis (triethoxysilylpropyl) tetrasulfide, γ-isocyanatopropyltriethoxysilane, trimethylsilyl isocyanate, dimethylsilyl isocyanate, phenylsilyl triisocyanate, tetra Examples include isocyanate group-functional silanes such as isocyanate silane, methylsilyl triisocyanate, vinylsilyl triisocyanate, and ethoxysilane triisocyanate.

  A functional group may be imparted to the surface of the fine particles using these silane coupling agents. As a result, at least one of attractive forces among the covalent bonds, the intermolecular forces, and the van der Waals forces between the fine particles and between the fine particles and the substrate can be reliably applied.

  Examples of commercially available silane coupling agents include KA-1003 having a vinyl group, KBM-1003, KBE-1003, KBM-303 having an epoxy group, KBM-403, KBE-402, KBE-403, and a styryl group. KBM-1403 having a methacryloxy group, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103 having an acryloxy group, KBM-602 having an amino group, KBM-603, KBE-603, KBM-903, KBE-903, KBE-9103, KBM-573, KBM-575, KBM-6123, KBE-585 having a ureido group, KBM-703 having a chloropropyl group, KBM-802 having a mercapto group, KBM -803, with sulfide group That KBE-846, KBE-9007 (Shin-Etsu Chemical none Co., Ltd., trade name) having an isocyanate group and the like.

  Alternatively, the intermediate layer may be formed using a primer in which the silane coupling agent is already diluted in a solvent or water. Examples of commercially available primers include KBP-40, KBP-41, KBP-43, KBP-90 diluted with a silane coupling agent having an amino group, and KBP-44 diluted with a silane coupling agent having an isocyanate group. And X-12-414 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) diluted with a silane coupling agent having a mercapto group.

  A resin having a polar group is preferably used for the intermediate layer in order to obtain adhesion between the solid substrate and the intermediate layer. As a coating method that can be adopted when forming a silane coupling agent or resin as an intermediate layer on a solid substrate, it can be performed by a well-known method, for example, reverse roll coating method, gravure coating method, etc. Kiss coating method, roll brushing method, spray coating method, air knife coating method, wire barber coating method, pipe doctor method and curtain coating method, spin coating method, dip coating method, alternating lamination method, etc. can be adopted . These methods can be performed alone or in combination. In any coating method, it is desirable to dilute the concentration of the coating solution so that the intermediate layer follows the fine structure.

  In order to ensure adhesion between the solid substrate and the intermediate layer, the solid substrate is subjected to corona discharge treatment, glow discharge treatment, plasma treatment, ultraviolet irradiation, ozone treatment, chemical etching treatment with alkali or acid, etc. Also good.

  An electrolyte polymer layer may be formed for the purpose of making the charge density of the surface of the solid substrate (which may include an intermediate layer) uniform and adsorbing fine particles evenly. For the electrolyte polymer, polydiallyldimethylammonium chloride (PDDA) having a positive charge, polyethyleneimine (PEI), or sodium polystyrene sulfonate (PSS) having a negative charge is preferable.

  In addition, as shown in Advanced Material, Vol. 13, pp. 52-54 (issued in 2001), an alternating lamination method is used to form an alternating laminated film of two types of electrolyte polymers with different charge signs. (It may include an intermediate layer).

  When these electrolyte polymer layers are formed on the surface of the solid substrate as an intermediate layer, it is desirable that the electrolyte polymer layer is in close contact with the solid substrate. When the solid substrate or the solid substrate surface layer is a polymer, the electrolyte polymer or the like is bonded to the polymer on the surface of the solid substrate by a conventionally known method such as heat, light, electron beam, or γ ray. The method of letting it be mentioned.

  Moreover, you may graft the monomer which has a polar group on a solid base material using this method. Examples of the monomer having a polar group include acrylic acid or methacrylic acid or an alkali metal salt or amine salt thereof, itaconic acid or an alkali metal salt or amine acid salt thereof, allylamine or a hydrogen halide salt thereof, or 3-vinyl propionic acid. Or its alkali metal salt or amine salt, vinyl sulfonic acid or its alkali metal salt or amine salt, vinyl styrene sulfonic acid or its alkali metal salt or amine salt, 2-sulfoethylene acrylate, 2-sulfoethylene methacrylate, 3-sulfopropylene Acrylate, 3-sulfopropylene methacrylate or an alkali metal salt or amine salt thereof, 2-acrylamido-2-methylpropanesulfonic acid or an alkali metal salt or amine salt thereof, mono (2-acryloyl) Oxyethyl) acid phosphate, mono (2-methacryloyloxyethyl) acid phosphate, phosphoric acid monomer or an alkali metal salt or amine salt thereof, such as acidphosphoxyethyl polyethylene glycol mono (meth) acrylate and the like.

(E) Method for forming fine particle laminated film and method for producing low refractive index film Langmuir, Vol. 13, pp. 6195-6203, (1997), contacting a solid substrate with an electrolyte polymer solution (polycation solution or polyanion solution) and contacting a fine particle dispersion solution having a positive or negative charge. By a method of alternately repeating (alternate lamination method), a fine particle laminated film can be formed on a solid substrate (steps (i) to (iii) in the first aspect, (i) to (2) in the second aspect) (Iv) step). The number of repetitions is not particularly limited, but the thickness of the thin film can be controlled by the number of repetitions. In the above alternate lamination method, the number of times of repeating alternately is preferably 1 to 100 times in order to ensure transparency. Moreover, in said alternating lamination method, it is preferable to complete | finish in the process contacted with a fine particle dispersion solution rather than the process contacted with an electrolyte polymer solution.

  A method for forming such a fine particle laminated film will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a process of forming a fine particle laminated film by an alternating lamination method. FIG. 1A shows a state after the electrolyte polymer solution and the fine particle dispersion are brought into contact with the substrate only once. The polycation (electrolyte polymer) 12 is in contact with the substrate (solid substrate) 10. Furthermore, fine particles 14 are in contact with the polycation 12. FIG. 1B shows a state after the alternate lamination is further performed twice with respect to the state of FIG. As shown in FIG. 1B, the fine particle laminated film 16 is formed by alternating lamination, and a void 18 is formed inside the layer.

  FIG. 2 schematically shows a step of bringing a polycation solution into contact with a silicon compound to be described later with respect to the fine particle laminated film that has been alternately laminated as described above. 2A shows the fine particle laminated film 16 formed in FIG. 1, and FIG. 2B shows that the silicon compound solution is brought into contact with the fine particle laminated film 16, and the product 20 of the silicon compound solution makes contact with the substrate 10. A state in which the fine particles 14 or the fine particles 14 are bonded to each other is shown.

  When the adsorption progresses in each step and the surface charge is reversed, further electrostatic adsorption does not occur. Therefore, the thickness of the film formed by one contact of the electrolyte polymer solution or the fine particle dispersion solution can be controlled. . Further, the material that is physically adsorbed excessively can be removed by rinsing the adsorption surface.

  Furthermore, as long as the surface charge is reversed, the film formation can be continued. Therefore, the film thickness uniformity of the thin film formed by the alternating lamination method is higher and the film thickness controllability is higher than the normal dip coating method. High film thickness controllability is important for the fine particle laminated film to exhibit a desired optical function by the optical interference effect.

  In the production method of the present invention, the rinsing liquid used in the rinsing step in each step is preferably water, an organic solvent, or a mixed solvent such as water and a water-soluble organic solvent. Water or a mixed solvent of water and a water-soluble organic solvent is more preferable for environmental protection and equipment explosion-proofing, and the ratio of mixing the water-soluble organic solvent with water is preferably 40% or less. Examples of the water-soluble organic solvent include methanol, ethanol, propanol, acetone, dimethylformamide, acetonitrile and the like.

  As an apparatus for forming a fine particle laminated film, J.A. Appl. Phys. , Vol. 79, pp. As shown in 7501-7509, (1996) and International Publication No. 2000/013806, the arm on which the solid substrate is fixed automatically moves, and the solid substrate is moved into the electrolyte polymer solution or the fine particle dispersion according to the program. Or you may use the apparatus called a dipper to immerse in a rinse liquid.

  Further, the fine particle laminated film may be formed by dropping or spraying an electrolyte polymer solution or a fine particle dispersion on a solid substrate. At that time, the rinsing liquid may be supplied by any of dripping, spraying, showering, or a combined method. Further, the solid substrate may perform movement such as conveyance and rotation.

(F) Fine particle dispersion The fine particle dispersion used in the present invention is obtained by dispersing fine particles described later in a medium (liquid) that is a mixed solvent such as water, an organic solvent, or water and a water-soluble organic solvent. is there. Water or a mixed solvent of water and a water-soluble organic solvent is preferable for environmental protection and equipment explosion-proofing, and the ratio of mixing the water-soluble organic solvent with water is preferably 40% or less. Examples of the water-soluble organic solvent include methanol, ethanol, propanol, acetone, dimethylformamide, acetonitrile and the like.

  The proportion of fine particles in the fine particle dispersion is usually preferably 0.005% by mass to 15% by mass, more preferably 0.001% by mass to 10% by mass, and more preferably 0.01% by mass to 5% by mass. Further preferred. When the proportion of the fine particles is 0.005 mass% or more and 15 mass% or less, the fine particle laminated film can be formed without agglomeration and without impairing transparency and flatness.

  When the dispersibility of the fine particles is low, a so-called dispersant can be used when preparing the fine particle dispersion in order to improve the dispersibility. As such a dispersant, a surfactant, an electrolyte polymer, a nonionic polymer, or the like can be used. The amount of these dispersants to be used varies depending on the type of the dispersant to be used, but in general, the amount of the dispersant with respect to the fine particles is preferably 0.00001 to 1% by mass, and within this range, Gelation / separation does not occur, the fine particles are not electrically neutral in the dispersion, and a fine particle laminated film is easily obtained.

  The pH of the fine particle dispersion can be adjusted in the range of 1 to 13 with an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide or an acidic aqueous solution such as hydrochloric acid or sulfuric acid, and the pH can also be adjusted with a dispersant. Can do. As the pH of the fine particle dispersion deviates from the equipotential point, the electrostatic attractive force with the solid substrate or the electrolyte polymer tends to increase. The equipotential point is a pH value at which the surface potential of the fine particles becomes 0 and the electrostatic repulsion force disappears, so that the particles aggregate. However, the equipotential point varies depending on the number of surface hydroxyl groups and the crystal structure. It depends on the material.

(G) Fine particle material The average primary particle size of the fine particles dispersed in the fine particle dispersion used in the present invention is 1 nm or more and 100 nm or less, so that the fine particle laminated film has high transparency. In order not to impair the geometrical optical performance of the structure, it is preferably 2 nm or more and 40 nm or less, more preferably 3 nm or more and 20 nm or less. When the average primary particle diameter is 1 nm or more and 100 nm or less, it becomes easy to form a transparent fine particle laminated film. Especially, when there is a fine structure on the surface of the solid substrate, the geometric optical performance of the fine structure. Can be secured.

In addition, when the fine particle laminated film is formed by the alternating lamination method, the amount of change in the film thickness of the fine particle laminated film per one alternate lamination is usually about the same as the average primary particle diameter of the fine particles. Therefore, if the average primary particle size is too large, the accuracy of film thickness control is lowered, and it is difficult to obtain a film thickness with high accuracy in terms of optical function expression.
In addition, the film thickness d ₁ necessary for the optical function expression of the fine particle laminated film is represented by the following formula.

(Where, λ is the wavelength at which the optical function is desired to be developed, n is the refractive index of the film, and x is usually 2 to 8) (Optical Thin Film Technology, Japan Opto-Mechatronics Association, Mikio Okamoto, pp 7-45, issued January 15, 2002, see).

  In the present invention, the average primary particle diameter, the average secondary particle diameter, and the particle diameter of particles having a shape in which primary particles are connected can be measured using a known method. In the present invention, particles having a shape in which primary particles are connected may be expressed as beaded particles.

  When primary particles are not aggregated but are dispersed in the fine particle dispersion, the average primary particle diameter can be measured by a dynamic scattering method. However, in the case of secondary particles in which primary particles are aggregated or beaded particles in which primary particles are covalently bonded, it is not the average primary particles that are measured by the dynamic scattering method. This is the particle size of the beaded particles. The average primary particle diameter in secondary particles or beaded particles can be measured by the BET method or electron microscopy.

  In the BET method, molecules with an occupied area such as nitrogen gas are adsorbed on the particle surface, the specific surface area is obtained from the relationship between the adsorbed amount and the pressure, and the specific surface area is converted from the conversion table into the particle diameter. The average primary particle size can be determined.

  In electron microscopy, first, fine particles are scooped from a fine particle dispersion on a copper mesh on which an amorphous carbon film having a thickness of several tens of nm is formed, or fine particles are adsorbed on the amorphous carbon film. These fine particles are observed with a transmission electron microscope, then the lengths of all the fine particles in the photographed image are measured, and the arithmetic average thereof is obtained as the average primary particle diameter.

  Note that the number of fine particles for measuring the length is desirably 100 or more, and when the number of fine particles in one photographed image is less than 100, it is set to 100 or more using a plurality of photographed images. When the axial ratios of the particles are greatly different as in the case of columnar particles, the length of the minor axis is generally measured, and the arithmetic average is taken as the average primary particle diameter.

  The fine particles in the above-mentioned particle diameter measurement may be obtained not only from the fine particle dispersion for preparing the fine particle laminated film but also from the fine particle laminated film. As a method of obtaining from the fine particle laminated film, the fine particle aggregate on the solid substrate is polished by steel wool (manufactured by Nippon Steel Wool Co., Ltd., # 0000) or a cutter, and the fine particle aggregate is peeled off. A method of dispersing the aggregate in a solvent can be mentioned.

The method and apparatus for dispersing the fine particle aggregate is not particularly limited, and examples thereof include a method of applying ultrasonic waves, a method of dispersing by a roll, a Banbury mixer, a kneader, a single screw extruder, a twin screw extruder, and the like.
Thereby, fine particle aggregates and monodispersed fine particles having a reduced size can be obtained. As the solvent, water, an organic solvent, or a mixed solvent such as water and a water-soluble organic solvent can be used.

In electron microscopy, the shape of the fine particles can be observed simultaneously with the particle size. It can be distinguished whether the primary particle has a porous structure, is hollow, or has a shape in which the primary particles are connected. The primary particles connected to each other are shaped as shown in FIG. 3 and may be called beaded particles in the present invention.
In addition, the numerical value of the average primary particle diameter prescribed | regulated in this invention is a numerical value obtained by BET method.

  In order to improve the strength of the fine particle laminated film, it is preferable that the primary particles are covalently bonded to each other. In the fine particle film using beaded particles, due to the steric hindrance caused by the beaded shape, other beaded particles and the electrolyte polymer having the opposite charge cannot occupy the space closely, resulting in spherical particles. It has a higher porosity and a lower refractive index than the fine particle film using.

  In the bead-like particles as shown in FIG. 3, more than half of the bead-like particles dispersed in the solution are composed of four or more primary particles. Further, in the case of beaded particles, primary particles are not aggregated on a three-dimensional dumpling, and the number of particles adjacent to one primary particle often does not exceed 10. In the closest packing, the number of particles adjacent to one primary particle is 16.

The arrangement of primary particles in the bead-shaped particles is characterized in that the portion where the number of particles adjacent to one primary particle is 1 or more and 8 or less occupies half or more. For this reason, the bead-like particles are easy to take a two-dimensionally expanded shape when adsorbed on the base material, and contribute to the improvement of the film forming property.
Furthermore, when the primary particles are covalently bonded, the strength of the fine particle laminated film is also improved.

The fine particles in the present invention include inorganic fine particles. Specifically, lithium, sodium, magnesium, aluminum, zinc, indium, silicon, tin, titanium, zirconium, yttrium, bismuth, niobium, cerium, cobalt, copper, iron , Holmium, manganese and other halides and oxides are used. More specifically, lithium fluoride (LiF), sodium fluoride (NaF), magnesium fluoride (MgF ₂ ), aluminum fluoride ( AlF ₃ ), aluminum oxide (Al ₂ O ₃ ), zinc oxide (ZnO), indium tin oxide (ITO), silica (SiO ₂ ), tin oxide (SnO ₂ ), titanium oxide (TiO ₂ ), zirconium oxide ( ZrO _2), yttrium oxide _{(Y 2 O} 3), bismuth oxide (Bi O _3), niobium oxide _{(Nb 2 O} 5), ceria _(CeO 2), cobalt oxide (CoO), copper (CuO), iron _{(Fe 2 O} 3), holmium _{(Ho 2 O} 3), manganese (Mn ₃ O _4), and the like. these may be used alone or in combination of two or more. The fine particles may be indefinite, and there are no particular limitations on the crystal form that can be obtained.

Among the inorganic fine particles, silica (SiO ₂ ) is preferable in that a thin film having a low refractive index required for an antireflection film can be obtained, and water-dispersed colloidal silica (average primary particle diameter controlled to 1 nm to 100 nm) ( Most preferred is SiO ₂ ). When the average primary particle diameter is 100 nm or less, it becomes easy to form a transparent fine particle laminated film, and when there is a fine structure on the surface of the solid substrate, the geometric optical performance of the fine structure can be ensured. it can. Examples of such commercially available inorganic fine particles include Snowtex (manufactured by Nissan Chemical Industries).

Furthermore, in terms of shape, it is preferable to use one or more of porous silica fine particles, hollow silica fine particles, and silica fine particles having a shape in which primary particles are connected. This is because when the fine particle laminated film is formed using particles having a shape in which the primary particles are connected, densification is inhibited by steric hindrance, so that the refractive index of the fine particle laminated film is lowered.
Further, when the fine particle laminated film is formed using porous particles and hollow particles, voids on the surface of the porous particles and voids inside the hollow particles are introduced, and the refractive index of the fine particle laminated film is lowered.

  The porous silica fine particles preferably have a porosity of 10 to 70% and preferably have pores having an inner diameter of 1 to 25 nm. As an example of the production method, 1 mmol of hydrochloric acid and 40 mL of water are added to 0.1 mol of tetraethoxysilane, and 10 wt% of gelatin is further added, followed by hydrolysis at room temperature for 1 hour, followed by drying at 50 ° C., air The temperature is raised to 600 ° C. at a rate of 1 ° C./min to obtain a silica-based porous body having pores generated by removing gelatin.

Furthermore, an aqueous dispersion of porous silica fine particles having a diameter of several tens of nm can be obtained by pulverizing the porous body in water by a bead mill or the like. Examples of commercially available products include Nipsil and Nipgel manufactured by Nippon Silica Kogyo.
As the hollow silica fine particles, those having a void ratio of 10 to 50% with respect to the fine particles are preferable, and examples of commercially available ones include Julia Catalyzer's through rear.

  In order to obtain a lower refractive index, it is more preferable that the basic fine particles contain a bead-shaped particle shape as shown in FIG. Commercially available products include SNOWTEX UP, SNOWTEX PS-S, SNOWTEX PS-M (trade name, manufactured by Nissan Chemical Industries, Ltd.) and Fine Catalloy F120 (product name, manufactured by JGC Catalysts & Chemicals, Inc.). There is a pearl necklace-like silica sol.

  As the fine particles in the present invention, polymer fine particles can also be used, and examples thereof include polyethylene, polystyrene, acrylic polymer, silicone polymer, phenol resin, polyamide, natural polymer, and these can be used alone or in combination of two or more. Can be used as a mixture.

  From liquid phase to solution spray method, solvent removal method, aqueous solution reaction method, emulsion method, suspension polymerization method, dispersion polymerization method, alkoxide hydrolysis method (sol-gel method), hydrothermal reaction method, chemical reduction method, liquid It is synthesized by a manufacturing method such as medium pulse laser ablation. Examples of commercially available polymer fine particles include Mist Pearl (manufactured by Arakawa Chemical Industries, Ltd.).

  In addition, an ionic functional group may be added to the surface of these fine particles for the purpose of giving at least one of at least one of covalent bond, intermolecular force, and van der Waals force between the fine particles and the fine particle-substrate. Good. The functional group can be imparted to the surface of the fine particles by subjecting the silane coupling agent represented by the general formula (I) to a condensation reaction with the hydroxyl groups of the fine particles.

  Examples of the functional group imparted to the surface of the fine particles include the above-described vinyl group, epoxy group, styryl group, methacryloxy group, acryloxy group, amino group, ureido group, chloropropyl group, sulfide group, mercapto group, and isocyanate group. Can do.

  Examples of commercially available silane couplings include KBM series and KBE series manufactured by Shin-Etsu Chemical. In addition, a carboxyl group, a carbonyl group, a phenol group, or the like may be imparted to the surface of the fine particles. Examples of commercially available fine particles having such functional groups on the surface include Mist Pearl (manufactured by Arakawa Chemical Industries, Ltd., Trade name) and the like.

  The fine particles dispersed in the medium are electrically negatively or positively charged because a diffusion electric double layer is generated by dissociation of surface polar groups and adsorption of ions. The thickness (1 / κ) of the diffusion electric double layer on the surface of the fine particles expressed by the following formula is a distance where the attractive force between the surface charge and the counter ion (electrolyte ion) balances with the force due to thermal motion. Here, κ is called a Debye-Huckel parameter and is expressed as the following equation (Hiroyuki Oshima, “Dispersion stability / aggregation control of nanoparticle and measurement evaluation of zeta potential”, Technical Information Association).

(Wherein, k is Boltzmann constant, epsilon ₀ is the vacuum dielectric constant, epsilon _r is the relative dielectric constant of the medium (liquid), T is an absolute temperature, Z is valence, e is the unit charge, _{N A} is Avogadro's number, C is the electrolyte concentration, and the unit is M (= mol / liter).)

The surface potential (φ ₀ ) of the fine particles is the product of the electric field (σ / ε _r ε ₀ ) and the electric double layer (1 / κ) due to the surface charge density (σ), and is represented by the following equation. From this equation, it can be seen that the surface potential (φ ₀ ) of the fine particles can be controlled by the surface charge density (σ) and the electrolyte concentration (C).

The electrolyte added to increase the electrolyte concentration is not limited as long as it dissolves in water or water, a mixed solvent of alcohol, etc., but is a salt of an alkali metal and alkaline earth metal, a quaternary ammonium ion, etc. and a halogen element. LiCl, KCl, NaCl, MgCl ₂ , CaCl ₂ or the like is used.

  The surface charge density (σ) can be controlled by pH. This is because the degree of dissociation (ionization) of the dissociating group on the particle surface is affected by pH. For example, when there are carboxyl groups (—COOH) or surface hydroxyl groups (—OH) on the surface of the fine particles, ionization occurs as carboxylate anions (—COO—) or hydroxide ions (—O—) when the pH is raised. Therefore, the charge density σ increases.

On the other hand, when there is an amino group (—NH ₂ ), when the pH is lowered, ammonium ions (—NH ₃ ⁺ ) are formed and the charge density is increased. That is, there is an increase in charge density in the high pH region and the low pH region.

  The fine particles having the same sign on the surface potential repel each other and stably disperse in the medium without agglomeration. The zeta potential reflects the surface charge of fine particles and is used as an indicator of the dispersion stability of fine particles (Fumio Kitahara, Kunio Furusawa, Masataka Ozaki, Hiroyuki Oshima, “Zeta Potential Zeta Potential: Physical Chemistry of Fine Particle Interfaces”, Scientist Issued in January 1995). If the absolute value of the zeta potential increases, the repulsive force between the fine particles becomes strong and the stability of the particles becomes high. Conversely, when the zeta potential approaches zero, the fine particles tend to aggregate.

  This zeta potential can be measured, for example, by an electrophoretic light scattering measurement method (also called a laser Doppler method). Irradiate fine particles migrating with an external electric field (E) with laser light of wavelength (λ), measure the frequency change (Doppler shift amount Δν) of the light scattered at the scattering angle (θ), (V) is obtained.

  Here, n is the refractive index of the medium (liquid). From the migration velocity (V) and the external electric field (E) obtained here, the electric mobility (U) is obtained from the following equation.

  The zeta potential (ζ) can be obtained from the electric mobility (U) using the following Smoluchowski equation.

(Where η is the viscosity of the medium (liquid), and ε is the dielectric constant of the medium (liquid) (Fumio Kitahara, Kunio Furusawa, Masataka Ozaki, Hiroyuki Oshima, “Zeta Potential Zeta Potential: Physical Chemistry of Fine Particle Interface”, Scientist Issued in January 1995)).

As a relatively new method for measuring the zeta potential, an ultrasonic method or a colloid oscillating current method can also be mentioned. Examples of the measuring apparatus include trade names DT-200, DT-1200, and DT-300 manufactured by Dispersion Technology.
Since the fine particles in the solvent irradiated with ultrasonic waves vibrate relatively due to the density difference between the solvent and the fine particles, an electric field called a colloid vibration potential is generated by the polarization of the charged fine particles and the surrounding counter ions. The zeta potential can be measured by detecting and analyzing this electric field.

  In inorganic oxide particles, the zeta potential changes greatly when the pH of the dispersion changes. For example, when the pH of the solution in which titania particles (Nippon Aerosil Co., Ltd.) are dispersed is changed to 3, 7.5, and 11, the zeta potential changes to +40 mV, 0 mV, and −20 mV, and the particle diameters are 400 nm, 1600 nm, and 900 nm. And change.

  That is, it can be seen that the particles aggregate when the zeta potential becomes 0 mV (Otsuka Electronics Co., Ltd., application note, zeta potential “measurement of zeta potential of inorganic substances”, p. LS-N002-6, issued on September 1, 2002). . Therefore, in order to stably disperse the fine particles in the solution, it is desirable to control the absolute value of the zeta potential of the fine particles in the range of several mV to several tens of mV.

  The silica fine particle aqueous dispersion (Snowtex (ST) 20) manufactured by Nissan Chemical Co., Ltd. adjusted to 1% by mass has a pH of 10, and the zeta potential of the fine silica particles is −48 mV. When the pH of the silica fine particle dispersion is adjusted to 9, the zeta potential of the silica fine particles becomes −45 mV. Further, when sodium chloride is added to a silica fine particle aqueous dispersion having a pH of 10 to prepare a silica fine particle aqueous dispersion having a sodium chloride concentration of 0.25 mol / liter, the zeta potential of the silica fine particles becomes −40 mV.

  In a silica fine particle laminated film produced by an alternating lamination method using a silica fine particle aqueous dispersion and a 0.3% by mass aqueous solution of polydiallyldimethylammonium chloride (PDDA), the silica fine particle laminated film is obtained when the zeta potential is −48 mV. The refractive index is 1.31, whereas the refractive index is 1.29 when the zeta potential is −45 mV and −40 mV. When the fine particle volume ratio is obtained from the refractive index of 1.31, 60% is obtained, and when the fine particle volume ratio is obtained from the refractive index of 1.29, it is 56%. From this, the decrease in the refractive index is considered to be due to the decrease in the volume fraction of the fine particles due to the decrease in the zeta potential of the fine particles. That is, the refractive index of the fine particle multilayer film can be controlled by controlling the zeta potential of the fine particles.

The kind of fine particles contained in the fine particle laminated film is not limited to one. For example, two or more kinds of fine particles may be adsorbed in one contact of the fine particle dispersion solution, and the kind of fine particles may be different for each contact of the fine particle dispersion solution.
Note that fine particles of titanium oxide, cerium oxide, niobium oxide, tin oxide, aluminum oxide, and silicon oxide are preferable from the viewpoint of increasing the surface hardness of the fine particle laminated film.

(H) Electrolyte polymer solution (polycation solution / polyanion solution)
A polycation solution and a polyanion solution (hereinafter, these may be collectively referred to as “electrolyte polymer solution”) are necessary for the production of a fine particle laminated film using an alternating lamination method. This electrolyte polymer solution is obtained by dissolving an electrolyte polymer having a charge opposite to or having the same sign as the surface charge of fine particles in water, an organic solvent, or a mixed solvent of water-soluble organic solvent and water. Water or a mixed solvent of water and a water-soluble organic solvent is preferable for environmental protection and equipment explosion-proofing, and the ratio of mixing the water-soluble organic solvent with water is preferably 40% or less. Examples of the water-soluble organic solvent include methanol, ethanol, propanol, acetone, dimethylformamide, acetonitrile and the like.

As the electrolyte polymer, a polymer having a charged functional group in the main chain or side chain can be used.
The ionic group in the electrolyte polymer solution is preferably at least one selected from the group consisting of primary, secondary or tertiary amino groups, salts of the amino groups, and quaternary ammonium type groups. That is, the electrolyte polymer preferably has the ionic group. Below, it illustrates about an electrolyte polymer.

  The polyanion generally has a functional group that can be negatively charged, such as sulfonic acid, sulfuric acid, carboxylic acid, etc., for example, polystyrene sulfonic acid (PSS), polyvinyl sulfate (PVS), dextran sulfate, Chondroitin sulfate, polyacrylic acid (PAA), polymethacrylic acid (PMA), polymaleic acid, polyfumaric acid, polyparaphenylene (−), polythiophene-3-acetic acid, polyamic acid, and a co-polymer containing at least one of them A polymer etc. can be used. Also, charged living organisms such as functional polymer ions such as poly (aniline-N-propanesulfonic acid) (PAN), various deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and charged polysaccharides such as pectin. Polymers can also be used.

The polycation is preferably a primary to tertiary amino group or a quaternary ammonium group. The surface hydroxyl group of silica and amino group or ammonium group are relatively strongly bonded.
For example, polyethyleneimine (PEI and its quaternized product), polyallylamine and its quaternized product, polyallylamine hydrochloride (PAH), polydiallyldimethylammonium chloride (PDDA), polyvinylpyridine (PVP), polylysine, polyacrylamide, polypyrrole Polyaniline, polyparaphenylene (+), polyparaphenylene vinylene, polyethylimine, a copolymer containing at least one of them, or a salt whose type is changed can be used.
More specifically, polyallylamine amide sulfate, copolymer of allylamine hydrochloride and diallylamine hydrochloride, copolymer of allylamine hydrochloride and dimethylallylamine hydrochloride, allylamine hydrochloride and other copolymers, partial methoxycarbonyl Allylamine polymer, partially methylcarbonylated allylamine acetate polymer, diallylamine hydrochloride polymer, methyldiallylamine hydrochloride polymer, methyldiallylamine amide sulfate polymer, methyldiallylamine acetate polymer, diallylamine hydrochloride and sulfur dioxide Copolymer, copolymer of diallylamine acetate and ion dioxide, copolymer of diallylmethylethylammonium ethyl sulfate and sulfur dioxide, copolymer of methyldiallylamine hydrochloride and sulfur dioxide, diallyldimethylan A copolymer of nium chloride and sulfur dioxide, a copolymer of diallyldimethylammonium chloride and acrylamide, a copolymer of diallyldimethylammonium chloride and a diallylamine hydrochloride derivative, a copolymer of dimethylamine and epichlorohydrin, Examples thereof include a copolymer of dimethylamine, ethylenediamine, and epichlorohydrin, and a copolymer of polyamide polyamine and epichlorohydrin.

These electrolyte polymers are either water-soluble or soluble in a mixed solution of water and an organic solvent, and the weight average molecular weight of the electrolyte polymer (measured by gel permeation chromatography using a standard polystyrene calibration curve). However, it is generally preferable that the value is 400 to 300,000.
The concentration of the electrolyte polymer in the solution is preferably 0.0003% by mass to 3% by mass, more preferably 0.001% by mass to 1% by mass, and further preferably 0.01% by mass to 1% by mass. preferable. If the concentration of the electrolyte polymer is too low, a fine particle laminate film cannot be formed, and if it is too high, removal of excess electrolyte polymer in the washing process becomes insufficient, and the fine particle laminate film becomes transparent and flat in order to produce aggregates. Damage.
The pH of the electrolyte polymer solution is preferably 5 or more and 12 or less, more preferably 6 or more and 11.5 or less, further preferably 7 or more and 11 or less, and further preferably 9 or more and 10.5 or less. If the pH is too low, the hydroxyl groups of the metal oxide fine particles cannot be activated, the amount of adsorption of the electrolyte polymer becomes nonuniform, and the film thickness of the fine particle multilayer film becomes nonuniform. If the pH is too high, the metal oxide is dissolved, so that the fine particle laminated film impairs transparency and flatness.

  By using polydiallyldimethylammonium chloride (PDDA), which is a polycation, and polystyrene sulfonic acid (PSS), which is a polyanion, a (PDDA / PSS) multilayer film can be produced by an alternate lamination method. The thickness of the 45-layer structure film (PDDA / PSS) formed on the silicon wafer with 45 times of alternate lamination is 60 nm, and the thickness of the PDDA / PSS film per alternate lamination is about 1.3 nm. it can. From this, it can be seen that the PDDA layer and the PSS layer are formed with a molecular order thinness. In addition, the monomolecular layer of PDDA and PSS is considered to be several tens from the molecular structure.

(I) Fine Particle Laminated Film The fine particle laminated film according to the present invention is obtained in the process of producing the low refractive index film of the present invention, and a polycation solution and a silicon compound solution are alternately brought into contact with the fine particle laminated film. Thus, the low refractive index film of the present invention can be produced.
The fine particle laminated film will be described in detail below.

  The refractive index of the fine particle laminated film can be controlled by selecting the fine particle material, and hence the refractive index of the low refractive index film of the present invention. The refractive index of the fine particle laminated film can be obtained by analysis from polarization characteristics measured by ellipsometry or analysis from reflection spectrum and transmission spectrum measured by a spectrophotometer. The advantage of these methods is that the film thickness of the fine particle laminated film can be evaluated simultaneously. Other methods for determining the film thickness of the fine particle laminated film include a method of observing a film such as SEM (scanning electron microscope), TEM (transmission electron microscope), and AFM (atomic force microscope). It is also possible to form a film on the quartz resonator and obtain the film thickness from the frequency change amount and the density of the film material.

  When polydiallyldimethylammonium chloride (PDDA) is used as an electrolyte polymer having a different charge from fine particles, the PDDA layer has a molecular order thickness of less than 1.3 nm as described above. Therefore, the PDDA layer is considered to cover the surface of the solid substrate or fine particles while following the surface shape. The thin substrate functions as an electrostatic binding material between the solid substrate and the fine particles and between the fine particles and the fine particles.

The refractive index of the fine particle laminated film is lower than the bulk of the fine particle material because a gap is formed between the fine particles in the fine particle laminated film. In particle laminated film according to the present invention the gap between the particles is almost air, the refractive index n _c of the particle laminated film can be determined from the following equation.

(In the formula, ρ _p represents the volume density of the fine particles in the fine particle laminated film, n _P represents the refractive index of the substance constituting the fine particles, and n ₀ represents the refractive index of air = 1.0.) (Thin Film / Light Device, Sadayoshi Yoshida, Hiroyoshi Yajima, The University of Tokyo Press, pp. 34-37, published September 20, 1994).

For example, the refractive index n _c is 1.8 next to the particle laminated film in which the refractive index n _P of the bulk is used titania fine particles of 2.3, particle laminated with silica particles having a refractive index n _P of the bulk 1.48 refractive index _{n c} of the film becomes 1.2. Thus, the fine particle laminated film exhibits a refractive index lower than that of the bulk of the fine particle material.

  The refractive index of the fine particle laminate film according to the present invention is preferably 1.10 or more and 1.28 or less, but if it is 1.10 or more and 1.28 or less, formation of the fine particle laminate film is easy, and silicon Even when the refractive index is increased by the compound entering the fine particle laminated film, the antireflection function does not deteriorate. The refractive index is preferably 1.14 or more and 1.28 or less, more preferably 1.14 or more and 1.25 or less, further preferably 1.15 or more and 1.23 or less, and further preferably 1.16 or more and 1.20 or less. preferable.

Although particle laminated film has voids in the film, because the size of the particles and the gap is sufficiently smaller than the wavelength of light (visible light), with an average refractive index n _c. Further, when the silicon compound is filled in the voids of the fine particle laminated film, the size of the voids of the fine particle laminated film is small, and even in that case, an average refractive index is exhibited. The antireflection film including these fine particle multilayer films or the antireflection film including the fine particle multilayer film containing a material other than the fine particles in the gap has an average refractive index and optically functions as a single layer film. .

  In a fine particle laminated film formed using particles having a shape in which primary particles are connected as shown in FIG. 3, densification is inhibited by steric hindrance between the particles, so that the refractive index of the fine particle laminated film is lowered. In that case, since voids larger than the particle diameter of the primary particles exist in the inside and surface of the fine particle laminated film, the internal voids are obtained by TEM (transmission electron microscope), and the surface voids are obtained by SEM (scanning electron microscope) or AFM. It can be observed with an atomic force microscope.

When the low refractive index film on the surface of the solid substrate having a refractive index n _s with the refractive index n _AR and the thickness d _AR as of the formula: is formed, the surface reflectance of the solid substrate at a wavelength λ 0 %.

For example, in order to set the surface reflectance of a transparent solid base material having a wavelength of 550 nm of n _S = 1.54 to 0%, a low refractive index film of n _AR = 1.241 and d _AR = 111 nm is used as a solid base. It is necessary to form on the surface of the material. FIG. 4 shows the relationship between the surface reflectance when an antireflection film is formed on a transparent solid substrate with n _S = 1.54 and the refractive index of the low refractive index film. Even if the refractive index of the low refractive index film is smaller or larger than n _AR, surface reflectivity of the solid substrate with a low refractive index film is increased from 0%.

On the other hand, the surface reflectance of a transparent solid substrate with n _S = 1.54 at a wavelength of 550 nm is 0.1%.
In order to achieve the following, n _C of the low refractive index film may be 1.203 or more and 1.281 or less.
Moreover, in order to make the surface reflectance of a transparent solid base material of n _S = 1.54 at a wavelength of 550 nm 1.0% or less, n _C of the low refractive index film is 1.123 or more and 1.372 or less. If it is. In the absence of a low refractive index film, the surface reflectance of a transparent solid substrate with n _S = 1.54 is 4.5%. Therefore, if a low refractive index film having a refractive index of 1.123 or more and 1.372 or less is formed on the surface of the solid substrate, the low refractive index film functions as an antireflection film.

The refractive index of the fine particle laminated film according to the present invention is smaller than the refractive index n _AR (see the above formula) that makes the surface reflectance of the solid substrate 0%. Therefore, even if the refractive index of the fine particle laminated film increases due to the silicon compound entering the fine particle laminated film, it continues to function as an antireflection film. For example, when the refractive index of the fine particle laminated film which was 1.372 is increased to 1.490 for some reason, the surface reflectance of the solid base material is increased from 1.0% to 3.3%. It is no longer an antireflection film.
However, when the refractive index of the fine particle laminated film, which was 1.123, increases to 1.241 due to the entry of the silicon compound into the fine laminated film, the surface reflectance of the solid base material is changed from 1.0% to 0.0%. The antireflection function is improved. For this reason, a low refractive index film in which a silicon compound is contained in a fine particle laminated film having a refractive index smaller than n _AR (see the above formula) functions as an excellent antireflection film.

  In addition, for use as an optical functional thin film other than the antireflection film, the fine particle laminated film having a low refractive index as in the present invention is useful for improving the optical performance and maintaining the optical function.

(J) Silicon compound solution and polycation solution The silicon compound solution used in the present invention has a general formula M ₂ O · nSiO ₂ (n = 0.5 to 8, M represents an alkali metal of Li, Na, or K). The water-soluble silicate shown by this is included. The n is preferably 0.5 to 4.0, more preferably 2.0 to 3.5.
The water-soluble silicate is not a single compound but a salt in which SiO ₂ (anhydrous silicic acid) and Na ₂ O (sodium oxide) are mixed in various ratios when M is Na (sodium). The molecular formula is represented by Na ₂ O · nSiO _2, where n is referred to as the molar ratio and represents the mixing ratio of Na ₂ O and SiO ₂ .

Since the silicon compound in the solution containing the water-soluble silicate is a negative electrolyte, a polycation is used for adsorption of the silicon compound. However, if the surface of the fine particle laminate film is positively charged, once the surface of the fine particle laminate film is made negative using an electrolyte polymer solution of polyanion, and then the polycation solution and the silicon compound solution are mixed. Adsorb alternately.
There are voids between the fine particles in the fine particle laminated film, and the polycation solution and the silicon compound solution enter the voids, so that the solid substrate, the fine particles, and the fine particles are bonded via the silicon compound. That means
Reaction formula M ₂ O · nSiO ₂ + 2nH ⁺ → 2M ⁺ + nH ₂ SiO _{3
nH 2 SiO 3 → - (O} -SiO) -n + nH 2 O
Silanol groups produced by dehydration of silicic acid (H ₂ SiO ₃ ) produced by the above are covalently bonded by hydroxyl bonding or polar groups on the surface of the fine particles by hydrogen bonding or dehydration condensation, and the silicon compound and fine particles are bonded.
That is, the silicon compound solution has a function of improving adhesion and strength, and since the water-soluble silicate is used for the solution, fluctuation of the solution due to mixing of water can be suppressed, and stable adhesion and strength can be obtained. it can. In addition, the process of forming the fine particle laminated film and the process of improving the adhesion and strength can be processed with one-line equipment, and the manufacturing cost can be reduced.

  The concentration of the water-soluble silicate in the silicon compound solution is preferably 0.1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 10% by mass or less from the viewpoint of exerting the effects of the present invention described above. . As the solvent, water can be preferably used. Although a water-soluble organic solvent may be mixed with water and used, there is a risk of gelation, so the ratio of mixing the water-soluble organic solvent with water is preferably 10% or less, more preferably 5% or less. Examples of the water-soluble organic solvent include methanol, ethanol, propanol, acetone, dimethylformamide, acetonitrile and the like.

  As the polycation in the polycation solution, the polycation described in the above-described electrolyte polymer solution can be used. Moreover, the preferable weight average molecular weight of polycation, a density | concentration, and pH of a polycation solution are the same as that of the electrolyte polymer solution as stated above.

As a method of bringing the silicon compound solution containing any of the above and the polycation solution into contact with the fine particle laminated film, a known method may be used. Any of a spray method, a dip method, a roll coating method, a spin coating method and the like is possible.
The silicon compound is dissolved in a diluting solvent to prepare a solution (silicon compound solution), and the solution can be brought into contact with the fine particle laminated film by the above methods. Dilution solvent for adjusting the concentration of silicon compound is water, lower alcohol such as methanol, ethanol, propanol and butanol, polar solvent such as ethyl acetate, acetone, dimethylformamide and acetonitrile, or a mixture of lower alcohol and polar solvent. A solvent is preferred.

  The low refractive index film obtained by bringing the silicon compound solution into contact with the fine particle laminated film has better substrate adhesion than the fine particle laminated film, and the difference between them can be known by a tape test. For example, a low refractive index film obtained by contacting a hydrolyzate of tetraethoxysilane with a fine particle laminated film is subjected to a tape test using an adhesive tape having an adhesive strength of 6.2 N / 20 mm (manufactured by Nitto Denko Corporation, 31B). Even if it does not peel off, the film does not decrease. However, when the tape test is performed on the fine particle laminated film under the same conditions, the fine particle laminated film is peeled off or reduced. Although the film thickness is reduced due to cohesive failure, the film thickness can be evaluated by evaluating the film thickness with an ellipsometer or analyzing the reflectance or transmittance measured with a spectrophotometer. Alternatively, it is possible to evaluate whether or not the film is reduced because light is scattered by unevenness caused by cohesive failure of the film. On the other hand, film peeling can be evaluated because the reflectance and transmittance substantially indicate the values of the substrate itself.

  In addition, the low refractive index film manufactured by the method for manufacturing a low refractive index film of the present invention functions as an antireflection film. That is, the antireflection film is manufactured by the method for manufacturing a low refractive index film of the present invention. Therefore, the description of each process in the manufacturing method of the low refractive index film of the present invention described above is valid as the description of the process in the manufacturing method of the antireflection film of the present invention.

  The coating solution set for low refractive index of the present invention includes the above electrolyte polymer solution, fine particle dispersion, polycation solution and silicon compound solution. By using these liquids as described above, the low refractive index film of the present invention can be formed.

(K) Optical member Since the fine particle laminated film according to the present invention is obtained by an alternating lamination method, the film thickness uniformity is high. Therefore, the low refractive index according to the present invention is obtained by bringing a silicon compound solution into contact with the fine particle laminated film. The rate film can be suitably used for an optical member. The low refractive index film of the present invention includes, for example, an antireflection film, a reflection film, a semi-transmission semi-reflection film, a visible light reflection infrared transmission film, an infrared reflection visible light transmission film, a blue reflection film, a green reflection film, a red reflection film, and a bright line. It can function as a film having a configuration in which two or more cut filter films and color tone correction films are added, and can particularly preferably function as an antireflection film.

  Therefore, the solid base material on which the low refractive index film of the present invention is formed includes, for example, a base material with an antireflection film, a base material with a reflection film (mirror), a base material with a semi-transmissive semi-reflective film (half mirror), and visible light. Base material with reflective infrared transmission film (cold mirror), base material with infrared reflection visible light transmission film (hot mirror), base material with blue reflection film, base material with green reflection film or base material with red reflection film (dichroic mirror) It can be used as a substrate with a bright line cut filter film or a substrate with a color tone correction film.

In many cases, the above function is expressed by a fine particle laminated film formed of a multilayer structure film formed by laminating a low refractive index film and a high refractive index film on a solid substrate while controlling the film thickness.
The range of the refractive index necessary for the expression of the optical function is generally 1.2 to 1.5 for a low refractive index film and 1.6 to 2.4 for a high refractive index film. The lower the refractive index of the low refractive index film, the better, and the higher the refractive index of the high refractive film, the better. The thickness necessary for the optical function expression can be obtained by the equation (equation for the thickness d _1). The refractive index can be adjusted by selecting fine particles as described above.

  An antireflection film having a multilayer structure includes an antireflection film having four or more layers in which a high refractive index film and a low refractive index film are alternately laminated on a solid substrate, and exhibits an antireflection function in a wide wavelength region. In this case, the greater the difference in refractive index between the low refractive index film and the high refractive index film, the better the antireflection performance. From the viewpoint of use in an actual antireflection film, the minimum value of the surface reflectance of the fine particle multilayer film in the visible light wavelength region is preferably 3% or less, more preferably 2% or less, and more preferably 1%. Or less, more preferably 0.5% or less.

The basic multilayer structure of the semi-transmissive / semi-reflective film is generally a four-layer structure in which two layers of a high refractive index film and a low refractive index film are sequentially laminated on a solid substrate and repeated twice. Although the thickness of each layer of the high refractive index film and a low refractive index film is the basic be closer to the above formula (formula for the thickness d _1), to flatten the reflection spectrum and the transmission spectrum in the wavelength region of interest For this reason, in order to reduce the wavelength dependence of the reflectance and transmittance, it may be slightly increased or decreased.

Incidentally, a single layer film of a high refractive index film, closer to the equation (equation for the thickness d _1), shows a semi-transmissive semi-reflective function in the wavelength region around the wavelength lambda. From the viewpoint of use in an actual semi-transmissive / semi-reflective film, the average value of the reflectance in the visible light wavelength region of the fine particle laminated film is 15% to 50% and the average value of the transmittance is 50% to 85% It is preferable that the average reflectance is 15% to 40% and the average transmittance is 60% to 85%, and the average reflectance is 15% to 30%. Further, the average value of the transmittance is more preferably 70% or more and 85% or less.

The basic multilayer structure of the reflective film is a two-layer structure in which two layers of a high refractive index film and a low refractive index film are sequentially laminated on a solid substrate, and the high refractive index film and the low refractive index are laminated. Although the film has an alternately laminated structure, the lowermost layer on the solid substrate side and the outermost surface layer are high refractive index films. The film thickness is determined by essentially each of the formulas (formula for obtaining the film thickness d _1). The higher the number of repetitions of the two-layer structure of the high refractive index film and the low refractive index film, the higher the reflectance.

  Further, the greater the difference in refractive index between the low refractive index film and the high refractive index film, the higher the reflectance even if the number of repetitions of the two-layer structure is the same. Therefore, by increasing the difference in refractive index between the low refractive index film and the high refractive index film, the number of repetitions of the two-layer structure necessary for obtaining a high reflectance can be reduced.

  A visible light reflecting infrared transmission film, an infrared reflection visible light transmission film, a blue reflection film, a green reflection film, a red reflection film, a bright line cut filter film, and a color tone correction film are characterized by high reflectivity at a specific wavelength. Therefore, the basic film structure is a multilayer structure such as a reflective film.

Formula As can be seen from (equation for refractive index n _c), the control of the change or fine volume density of the particulate material can be controlled refractive index of the particle laminated film, particle laminated with a high refractive index and low refractive index A membrane can be obtained. For example, if the volume density of fine particles is controlled to 60% by using fine particles of titanium oxide having a bulk refractive index of 2.3, ceria of 2.2, and tin oxide of 1.9, a refractive index of 1.89. A high refractive index film such as a titania fine particle laminated film, a ceria fine particle laminated film having a refractive index of 1.82 or a tin oxide fine particle laminated film having a refractive index of 1.60 is obtained.

  On the other hand, if the volume density of the fine particles is controlled to 50% using aluminum oxide having a bulk refractive index of 1.6 and silica fine particles of 1.48, a refractive index of 1.33 is obtained. A low refractive index film such as a silica fine particle laminated film having a rate of 1.26 is obtained. The fine particle volume density can be controlled by the fine particle zeta potential and the fine particle shape.

  In a fine structure whose fine structure is highly controlled and has high geometric optical performance, it is not desirable for the antireflection film or low refractive index film on the surface of the fine structure to scatter and diffuse visible light. This is because an antireflection film or a low refractive index film that scatters or diffuses light even slightly increases the degree of light scattering / diffusion when light is incident obliquely.

  In many cases, light is incident on the antireflection film on the surface of the fine structure not only from the normal direction but also at an oblique incidence. Therefore, for example, when an antireflection film or a low refractive index film that scatters and diffuses light is formed on the surface of the lens-shaped object, geometric optical performance degradation occurs such that the light does not collect at the focal point. That is, it is desirable that the antireflection film and the low refractive index film are transparent so that the antireflection film does not impair the geometric optical performance of the microstructure. In the present invention, by measuring the turbidity of the antireflection film or the low refractive index film, it can be evaluated that the antireflection film or the low refractive index film of the present invention does not impair the geometric optical performance of the microstructure.

  In a fine structure having a highly controlled fine structure and high geometric optical performance, it is desirable that the antireflection film on the surface of the fine structure be formed following the shape of the fine structure. When the antireflection film does not follow the shape of the fine structure, the geometric optical performance of the fine structure is impaired. Taking the lens-like microstructure as an example, if the antireflection film on the surface of the on-chip microlens array used in the solid-state imaging device does not follow the microlens, the amount of light collected will be reduced in order to impair the light collection performance of the lens. The sensitivity decreases due to the decrease, and the light irradiated to the part other than the photodiode becomes stray light, causing flare and contrast reduction.

  In the present invention, a low refractive index film is measured by observing a cross section of a fine structure on which a low refractive index film is formed with a scanning electron microscope or the like and measuring the thickness of the low refractive index film with respect to the normal direction from the surface of the fine structure. The followability of the rate film to the fine structure can be evaluated. In addition, the microstructure can be observed with a scanning electron microscope from an oblique direction, and the followability of the low refractive index film to the microstructure can be evaluated based on the projected shape of the microstructure.

In the present invention, since the solid substrate has a polar group on the surface, the fine particle laminated film formed thereon can obtain practical adhesion, and the fine particles and the substrate are bonded by the silicon compound. And better adhesion can be obtained. An example of a method for evaluating the surface hardness of a film on a solid substrate is a pencil hardness test. An apparatus that evaluates the hardness of the thin film itself without depending on the hardness of the solid substrate includes a nanoindenter.
Moreover, a tape peeling test is mentioned as a method of evaluating adhesiveness.

  The tape peeling test does not necessarily have an adhesive strength of 2.94 N / 10 mm or more as defined in JIS Z 1522, and the test may be performed using an adhesive tape used in a more actual process. In the manufacturing process of a semiconductor such as a photoelectric conversion element, a protective tape such as an adhesive tape used in the back grinding process corresponds to it.

  In addition, for optical function members such as Fresnel lenses and lenticular lenses used in LCD backlight brightness enhancement lens films, diffusion films, and video projection television screens, surface protection, contamination prevention, etc. Adhesive tape to be fixed to fix it.

(L) Heat treatment It is preferable to perform a heat treatment for heating the low refractive index film formed on the surface of the solid substrate as described above. Specifically, it is preferable to perform heat treatment after the step of adsorbing the polycation in the polycation solution and the water-soluble silicate in the silicon compound solution to the fine particle laminated film. The dehydration condensation between the silicon compound and the fine particles or the substrate is promoted, and the strength of the low refractive index film and the substrate adhesion are improved.

  The heating temperature is preferably lower than the melting point, glass transition temperature, softening temperature, etc. of the solid substrate, and is preferably a temperature at which the optical function such as transparency and non-coloring of the solid substrate is maintained. The heating temperature may exceed the melting point or boiling point of the electrolyte polymer in the fine particle laminated film.

Since the amount of the electrolyte polymer in the fine particle laminated film according to the present invention is extremely small, even if it is evaporated by heating and removed from the fine particle laminated film, the optical function and mechanical properties are maintained.
In addition, the electrolyte polymer is necessary as an electrostatic binder for the formation of the fine particle laminate film, but after the fine particle laminate film is formed, the electrolyte polymer exists because the fine particle laminate film is retained by the attractive force between fine particles. It may or may not exist.

  The heating time is preferably 1 minute to 24 hours. Of course, the relationship between the heating temperature and the heating time is relative, and when the processing temperature is lowered, the purpose can be achieved by continuing the processing for a longer time.

  The atmosphere for the heat treatment is not limited, and may be an oxidizing atmosphere such as air, an inert atmosphere such as nitrogen, or a reducing atmosphere including hydrogen. There is no restriction | limiting also in the heating method, It can carry out using heating means thru | or a heating apparatus like an oven, an induction heating apparatus, and an infrared heater.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[Example 1]
1. Formation of fine particle laminated film Silica aqueous dispersion in which bead-like silica fine particles having an average primary particle diameter of 8 nm measured by BET method are dispersed (manufactured by Nissan Chemical Industries, Ltd., trade name: Snowtex (ST) OUP, silica sol) Was used as a fine particle dispersion having a negative charge, the concentration of which was adjusted to 1% by mass without adjusting the pH, and an aqueous solution in which polydiallyldimethylammonium chloride (PDDA, manufactured by Aldrich) was adjusted to 0.1% by mass and pH 10. Was used as the polycation solution.

  Silicon wafer which is a solid substrate (SUMCO, 6PW-A1, 6 inch diameter, 625 μm thickness), glass substrate (Matsunami Glass, trade name: S1111, 25 mm × 75 mm × 0.7 mm thickness, wavelength 550 nm The refractive index is 1.54), a polycarbonate substrate subjected to plasma surface treatment (manufactured by Sumitomo Bakelite, EC105, 1 mm thickness), and a Fresnel lens (Nippon Special Optical Resin Co., Ltd., CF20) which is a fine structure. -0.1, 100 × 100 mm, PMMA, 2 mm thickness), each of which is immersed in a polycation solution for 1 minute and then showered with ultrapure water for rinsing for 1 minute (a), after being immersed in a fine particle dispersion for 1 minute A step (a) of showering ultrapure water for rinsing for 1 minute was performed in this order.

  Performing the step (a) once and the step (b) once in order was defined as one cycle, and this cycle number was defined as the number of fine particle alternating laminations. After performing the number of times of alternately laminating fine particles four times, drying was performed at 25 ° C. for 24 hours to form a fine particle laminated film on the surface of each solid substrate.

2. Silicon compound treatment Lithium silicate (Li ₂ O.3.5SiO ₂ manufactured by Nissan Chemical Co., Ltd., LSS-35) was used as a silicon compound solution prepared by adding ultrapure water to 10% by mass, and polydiallyldimethylammonium chloride (PDDA, An aqueous solution adjusted to 0.1 mass% and pH 10 was used as a polycation solution.
Step (c) of rinsing ultrapure water for rinsing for 1 minute after immersing in the polycation solution for 1 minute on each fixed base material on which the fine particle laminated thin film is formed, and rinsing for water after being immersed in a silicon compound solution for 1 minute The step (d) of showering the ultrapure water for 1 minute was performed in this order. Performing the step (c) once and the step (d) once in turn was defined as one cycle, and the number of cycles was defined as the number of silicon compound treatments. After performing the silicon compound treatment three times, the silicon compound was dried at 25 ° C. for 24 hours to form a low refractive index film on the surface of each solid substrate.

3. Evaluation of Refractive Index As a result of evaluating the refractive index and the film thickness of a low refractive index film on a silicon wafer with an automatic ellipsometer (manufactured by Fibravo Inc., trade name: MARY-102, laser wavelength 632.8 nm) The refractive index was 1.27 and the thickness was 110 nm.

4). Evaluation of Transparency As a result of measuring the haze value of the glass substrate on which the low refractive index film obtained above was formed with a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K 7361-1-1997, It was 0.4%. The haze value of the glass substrate alone was measured in the same manner and was found to be 0.1%. The turbidity of the low refractive index film was determined by subtracting the haze value of only the solid substrate from the haze value of the solid substrate on which the low refractive index film was formed. As a result, it was found that the turbidity of the low refractive index film was 0.3%, and the transparency of the low refractive index film was very high.

5. Evaluation of antireflection performance When the transmission spectrum of a glass substrate on which a low refractive index film was formed was measured with a visible ultraviolet spectrophotometer (trade name: V-570, manufactured by JASCO Corporation), the maximum at a wavelength of 400 to 800 nm. The transmittance of was 95%.
Further, a black adhesive tape (manufactured by Nichiban Co., Ltd., trade name: VT-196) was attached to the opposite surface of the glass substrate on which the low refractive index film was formed so that no bubbles remained, and the low refractive index film was formed. The spectrum of single-sided surface reflectance was measured with a visible ultraviolet spectrophotometer (trade name: V-570, manufactured by JASCO Corporation). The minimum surface reflectance at a wavelength of 400 to 800 nm of the glass substrate on which the low refractive index film was formed was 0.2%.
Since the transmittance of the glass substrate was 91% and the surface reflectance was 4.5%, it was found that an antireflection film having excellent characteristics was formed and the transmittance was also improved.

6). Evaluation of Adhesion An adhesive tape having an adhesive strength of 40 cN / 25 mm and a width of 25 mm (made by Hitachi Chemical Co., Ltd., trade name: Hitalex P-3010) was used, and a roll laminator (made by Lamy Corporation, trade name: LMP). -350EX), an adhesive tape was attached to the low refractive index film under the conditions of a roll load of 0.3 MPa, a feed rate of 0.3 m / min, and a temperature of 20 ° C.
Thirty minutes after the tape was brought into close contact, one end of the tape was lifted at a right angle to the substrate surface and peeled off instantaneously. As a result of visual observation of the low refractive index film, it was found that the low refractive index film was in close contact with the base material because the surface of the base material was not visible and the low refractive index film did not scatter visible light. The low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.

7). Evaluation of film strength A cotton swab (manufactured by Nippon Cotton Swab Co., Ltd.) impregnated with a lens cleaner (manufactured by Nippon Cotton Swab Co., Ltd.) is installed at 90 ° with respect to the low refractive index film, and a load of 50 g is applied at a speed of 1000 mm / min 1 round trip. As a result of visually observing the low refractive index film after the test, it was confirmed that the low refractive index film on the silicon substrate, the glass substrate, and the polycarbonate was not damaged.

8). Evaluation of shape followability The appearance of the Fresnel lens on which the low refractive index film was formed was visually observed. As a result of observation, no unevenness was found, and it was confirmed that the low refractive index film satisfactorily followed the shape of the Fresnel lens. Further, the cross section of the concave portion of the Fresnel lens on which the low refractive index film was formed was observed with a scanning electron microscope. FIG. 5 is a cross section of a Fresnel lens on which a low refractive index film is formed. The outline of the Fresnel lens is indicated by a solid line and the outline of the low refractive index film is indicated by a broken line. As a result of cross-sectional observation, it was confirmed that the low refractive index film on the Fresnel lens had a uniform thickness following the concave shape of the Fresnel lens.

[Example 2]
Except that pure water was added to lithium silicate (Li ₂ O · 4.5SiO ₂ Nissan Chemical Co., Ltd., LSS-45) and the silicon compound solution was adjusted to 10% by mass, the silicon compound treatment was carried out. A low refractive index film was prepared according to 1.

The refractive index of the low refractive index film evaluated in the same manner as in Example 1 was 1.27, the thickness was 110 nm, and the turbidity of the low refractive index film evaluated in the same manner as in Example 1 was 0.3%. . When the transmission spectrum of the glass substrate on which the low refractive index film was formed as in Example 1 was measured, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the low refractive index film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.
When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all 50 g and no flaw was generated.
As a result of visual observation of the Fresnel lens formed with the low refractive index film in the same manner as in Example 1, no unevenness was found, and it was confirmed that the low refractive index film satisfactorily followed the shape of the Fresnel lens. It was.

[Example 3]
Except that pure water was added to lithium silicate (Li ₂ O · 7.5SiO ₂ manufactured by Nissan Chemical Co., Ltd., LSS-75), and the silicon compound solution was adjusted to 10% by mass, the silicon compound treatment was carried out. A low refractive index film was prepared according to 1.

The refractive index of the low refractive index film evaluated in the same manner as in Example 1 was 1.27, the thickness was 112 nm, and the turbidity of the low refractive index film evaluated in the same manner as in Example 1 was 0.3%. . When the transmission spectrum of the glass substrate on which the low refractive index film was formed as in Example 1 was measured, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the low refractive index film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.
When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all 50 g and no flaw was generated.
As a result of visual observation of the Fresnel lens on which the low refractive index film was formed in the same manner as in Example 1, no unevenness occurred.

[Example 4]
Except that pure water was added to potassium silicate (K ₂ O.3.9SiO ₂ manufactured by Nissan Chemical Co., Ltd., ST-K2) and the silicon compound solution was adjusted to 5% by mass, the silicon compound treatment was carried out. A low refractive index film was prepared according to 1.

The refractive index of the low refractive index film evaluated in the same manner as in Example 1 was 1.27, the thickness was 108 nm, and the turbidity of the low refractive index film evaluated in the same manner as in Example 1 was 0.3%. . When the transmission spectrum of the glass substrate on which the low refractive index film was formed as in Example 1 was measured, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the low refractive index film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.
When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all 50 g and no flaw was generated.
As a result of visual observation of the Fresnel lens on which the low refractive index film was formed in the same manner as in Example 1, no unevenness occurred.

[Example 5]
Example 1 except that pure water was added to a sodium silicate solution (Na ₂ O · 2.2SiO ₂ Wako Pure Chemical Industries) and the silicon compound solution was adjusted to 5% by mass using a silicon compound solution. Similarly, a low refractive index film was produced.

The refractive index of the low refractive index film evaluated in the same manner as in Example 1 was 1.27, the thickness was 108 nm, and the turbidity of the low refractive index film evaluated in the same manner as in Example 1 was 0.3%. . When the transmission spectrum of the glass substrate on which the low refractive index film was formed as in Example 1 was measured, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the low refractive index film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.
When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all 50 g and no flaw was generated.
As a result of visual observation of the Fresnel lens on which the low refractive index film was formed in the same manner as in Example 1, no unevenness occurred.

[Example 6]
A low refractive index film was prepared in the same manner as in Example 1 except that polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd.) was adjusted to 0.1% by mass, and a fine particle laminated film was prepared using a polycation solution not adjusting pH. Produced.

The refractive index of the low refractive index film evaluated in the same manner as in Example 1 was 1.27, the thickness was 112 nm, and the turbidity of the low refractive index film evaluated in the same manner as in Example 1 was 0.3%. . When the transmission spectrum of the glass substrate on which the low refractive index film was formed as in Example 1 was measured, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the low refractive index film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.
When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all 50 g and no flaw was generated.
As a result of visual observation of the Fresnel lens on which the low refractive index film was formed in the same manner as in Example 1, no unevenness occurred.

[Example 7]
A low refractive index film was prepared in the same manner as in Example 6 except that polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd.) was adjusted to 0.1% by mass and the silicon compound treatment was performed using a polycation solution that does not adjust the pH. Produced.

The refractive index of the low refractive index film evaluated in the same manner as in Example 1 was 1.27, the thickness was 112 nm, and the turbidity of the low refractive index film evaluated in the same manner as in Example 1 was 0.3%. . When the transmission spectrum of the glass substrate on which the low refractive index film was formed as in Example 1 was measured, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the low refractive index film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.
When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all 50 g and no flaw was generated.
As a result of visual observation of the Fresnel lens on which the low refractive index film was formed in the same manner as in Example 1, no unevenness occurred.

[Example 8]
After producing the low refractive index film, a low refractive index film was produced according to Example 1 except that the heat treatment was performed at 120 ° C. for 12 hours.

The refractive index of the low refractive index film evaluated in the same manner as in Example 1 was 1.27, the thickness was 110 nm, and the turbidity of the low refractive index film evaluated in the same manner as in Example 1 was 0.3%. . When the transmission spectrum of the glass substrate on which the low refractive index film was formed as in Example 1 was measured, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the low refractive index film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.
When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate base material were all 100 g and no flaw was generated.

[Example 9]
After producing the low refractive index film, a low refractive index film was produced according to Example 7 except that the heat treatment was performed at 120 ° C. for 12 hours.

The refractive index of the low refractive index film evaluated in the same manner as in Example 1 was 1.27, the thickness was 112 nm, and the turbidity of the low refractive index film evaluated in the same manner as in Example 1 was 0.3%. . When the transmission spectrum of the glass substrate on which the low refractive index film was formed as in Example 1 was measured, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the low refractive index film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.
When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate base material were all 100 g and no flaw was generated.

[Comparative Example 1]
A fine particle laminated film was prepared according to Example 1, and the silicon compound treatment was not performed.

  The refractive index of the fine particle laminated film evaluated in the same manner as in Example 1 was 1.21, the thickness was 100 nm, and the turbidity of the fine particle laminated film evaluated in the same manner as in Example 1 was 0.3%. When the transmission spectrum of the glass substrate on which the fine particle laminated film was formed was measured in the same manner as in Example 1, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the fine particle laminated film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.

When the adhesion was evaluated in the same manner as in Example 1, both the low refractive index film on the silicon substrate and the glass substrate were in close contact with the base material, but the low refractive index film on the polycarbonate base material was partially It peeled.
When the film strength was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all damaged at 20 g.

[Comparative Example 2]
First, a fine particle laminated film was prepared according to Example 1.
Subsequently, ultrapure water was added to lithium silicate (Li ₂ O.3.5SiO ₂ Nissan Chemical Co., Ltd., LSS-35) to prepare a silicon compound solution adjusted to 10% by mass.
Silicon wafer which is a solid substrate (SUMCO, 6PW-A1, diameter 6 inches, 625 μm thickness), glass substrate (Matsunami Glass, product name: S1111, 25 mm × 75 mm × 0.7 mm thickness, wavelength 550 nm Has a refractive index of 1.54), a polycarbonate substrate (manufactured by Hikari Co., Ltd., transparent, 1 mm thickness) irradiated with ultraviolet rays for 2 minutes with a low-pressure mercury lamp (10 mW), and a Fresnel lens (Nippon Special Optical Resin, which is a fine structure) (Corporation, CF20-0.1, 100 × 100 mm, PMMA, 2 mm thickness) is subjected to 3 cycles of rinsing ultrapure water for 1 minute after being immersed in a silicon compound solution for 1 minute, A low refractive index film was obtained.

  The refractive index of the fine particle laminated film evaluated in the same manner as in Example 1 was 1.21, the thickness was 100 nm, and the turbidity of the fine particle laminated film evaluated in the same manner as in Example 1 was 0.3%. When the transmission spectrum of the glass substrate on which the fine particle laminated film was formed was measured in the same manner as in Example 1, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the fine particle laminated film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.

When the adhesion was evaluated in the same manner as in Example 1, both the low refractive index film on the silicon substrate and the glass substrate were in close contact with the base material, but the low refractive index film on the polycarbonate base material was partially It peeled.
When the film strength was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all damaged at 20 g.

[Comparative Example 3]
First, a fine particle laminated film was prepared according to Example 1.
Next, after putting 50 g of tetraethoxysilane (alkoxysilane, manufactured by Wako Pure Chemical Industries, Ltd., tetraethyl orthosilicate) into a 300 ml three-necked round bottom flask, adding 75 g of MeOH (methanol) and stirring the mixture at 25 ° C. to make the solution uniform 17.7g of H ₃ PO ₄ 1.3 mass% aqueous solution was added and stirred at 25 ° C for 24 hours to obtain a 35 mass% silane concentration solution. A 1-butanol / isopropyl alcohol mixed solvent (mixing ratio 50/50, mass ratio) was added to the silicon compound solution to obtain a silicon compound solution having a silane concentration adjusted to 1 mass%.
2g of 1-butanol / isopropyl alcohol mixed solvent (mixing ratio 50/50, mass ratio) is added to 1g of silane concentration, 1% by weight solution, and NovecHFE-7100 (HFE solvent, Sumitomo 3M Co., Ltd.) as a low surface tension component. 7 g of company) was added and diluted to a silane concentration, 0.1% by weight solution.
The fixed base material on which the fine particle laminated film was formed was immersed in the silicon compound solution and pulled up at 5 mm / second to obtain a low refractive index film.

  The refractive index of the fine particle laminated film evaluated in the same manner as in Example 1 was 1.27, the thickness was 110 nm, and the turbidity of the fine particle laminated film evaluated in the same manner as in Example 1 was 0.3%. When the transmission spectrum of the glass substrate on which the fine particle laminated film was formed was measured in the same manner as in Example 1, the maximum transmittance at a wavelength of 400 to 800 nm was 95%. When the surface reflection spectrum of the glass substrate on which the fine particle laminated film was formed was measured in the same manner as in Example 1, the minimum surface reflectance at a wavelength of 400 to 800 nm was 0.2%.

When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, it was confirmed that the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all 50 g and no flaw was generated.
As a result of visual observation of the Fresnel lens on which the low refractive index film was formed in the same manner as in Example 1, a crescent-shaped unevenness occurred in the lower part, and the low refractive index film could not be obtained following the shape of the Fresnel lens. The cross section of the portion where the unevenness of the Fresnel lens occurred was observed with a scanning electron microscope. FIG. 6 is a cross section of a concave portion of a Fresnel lens on which a low refractive index film is formed. The outline of the Fresnel lens is indicated by a solid line, and the outline of the low refractive index film is indicated by a broken line. As a result of cross-sectional observation, the low refractive index film on the Fresnel lens did not follow the concave shape of the Fresnel lens.

[Comparative Example 4]
A low refractive index film was produced in the same manner as in Comparative Example 3 except that the concentration of the silicon compound solution was changed to 0.01% by mass.

When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, the low refractive index film on the silicon substrate, the glass substrate, and the polycarbonate base material did not have any scratches at 20 g, but scratches occurred at 50 g.
As a result of visual observation of the Fresnel lens on which the low refractive index film was formed in the same manner as in Example 1, no unevenness occurred.

[Comparative Example 5]
A low refractive index film was produced in the same manner as in Comparative Example 3 except that the pulling speed of the silicon compound solution was set to 0.5 mm / second.

When the adhesion was evaluated in the same manner as in Example 1, the low refractive index films on the silicon substrate, the glass substrate, and the polycarbonate substrate were all in close contact with the substrate.
When the film strength was evaluated in the same manner as in Example 1, the low refractive index film on the silicon substrate, the glass substrate, and the polycarbonate base material did not have any scratches at 20 g, but scratches occurred at 50 g.
As a result of visual observation of the Fresnel lens on which the low refractive index film was formed in the same manner as in Example 1, no unevenness occurred.

The results of the above examples and comparative examples are shown in Table 1.
The adhesion was evaluated according to the following evaluation criteria and is shown in Table 1.
○: Good adhesion of the low refractive index film to the silicon substrate, glass substrate, polycarbonate base ×: Poor adhesion of the low refractive index film to the silicon substrate, glass substrate, polycarbonate base, peeling, and film strength Evaluation was made according to the following evaluation criteria, and the results are shown in Table 1.
A: Tested with a load of 100 g and no scratches occurred ○: Tested with a load of 50 g and no scratches occurred Δ: Tested with a load of 20 g and no scratches occurred ×: Scratched when tested with a load of 20 g Further, the shape followability was evaluated according to the following evaluation criteria and shown in Table 1.
○: Good followability to Fresnel lens ×: Poor followability to Fresnel lens, shape change

  From Table 1, it can be seen that the low refractive index film can be made to follow a fine structure such as a Fresnel lens by alternately adsorbing the electrolyte polymer solution and the silicon compound solution to the fine particle laminated film. Moreover, it turns out that base material adhesiveness and film | membrane intensity | strength can be provided to a low-refractive-index film by producing adsorption of a fine particle laminated film and a silicon compound by an alternating lamination method.

10 Substrate 12 Polycation (electrolyte polymer)
14 Fine particle 16 Fine particle laminated thin film 18 Void 20 Silicon compound solution product

Claims (8)

A method for producing a low refractive index film formed on the surface of a solid substrate having a microstructure on the surface,
(I) contacting the polycation solution with the surface of the solid substrate, and then rinsing;
(Ii) a step of bringing a dispersion of fine particles having a negative charge into contact with the surface of the solid substrate after (i), followed by a rinsing step;
(Iii) a step of alternately repeating (i) and (ii) to form a fine particle laminated film;
(Iv) a step of bringing a polycation solution into contact with the fine particle laminated film, followed by a rinsing step;
(V) In the fine particle laminated film after (iv), the general formula M ₂ O · nSiO ₂ (N = 0.5-8, M represents an alkali metal of Li, Na, or K), a step of contacting a silicon compound solution containing a water-soluble silicate, and a step of rinsing, and
(Vi) Steps of alternately repeating (iv) and (v) to adsorb the polycation in the polycation solution and the water-soluble silicate in the silicon compound solution to the fine particle laminate film,
A method for producing a low refractive index film, comprising: A method for producing a low refractive index film formed on the surface of a solid substrate having a microstructure on the surface,
(I) contacting the polycation solution with the surface of the solid substrate, and then rinsing;
(Ii) contacting the surface of the solid substrate after (i) with a polyanion solution, followed by rinsing;
(Iii) a step of bringing a dispersion of fine particles having a positive charge into contact with the surface of the solid substrate after (ii), followed by a rinsing step;
(Iv) a step of alternately repeating (ii) and (iii) to form a fine particle laminated film;
(V) a step of bringing a polyanion solution into contact with the fine particle laminated film, followed by a rinsing step;
(Vi) contacting the polycation solution with the fine particle layered film after (v), and then rinsing;
(Vii) In the fine particle laminated film after (vi), the general formula M ₂ O · nSiO ₂ (N = 0.5-8, M represents an alkali metal of Li, Na, or K), a step of contacting a silicon compound solution containing a water-soluble silicate, and a step of rinsing, and
(Viii) alternately repeating (vi) and (vii), and adsorbing the polycation in the polycation solution and the water-soluble silicate in the silicon compound solution to the fine particle laminate film,
A method for producing a low refractive index film, comprising: 3. The low refractive index according to claim 1, wherein heat treatment is performed after the step of adsorbing the polycation in the polycation solution and the water-soluble silicate in the silicon compound solution to the fine particle laminated film. A method for producing a membrane. The solid substrate is composed of an optical pickup lens, a small camera lens, a projector lens, an aspherical lens, a lenticular lens, a Fresnel lens, a prism, a microlens array, a light guiding microstructure, a light diffusing microstructure, and a hologram. The manufacturing method of the low-refractive-index film of any one of Claims 1-3 which has the fine structure for obtaining either selected from the group which consists of. The manufacturing method of the low-refractive-index film of any one of Claims 1-4 whose said solid base material is a plastic base material with a thermal expansion coefficient of 50-350 (ppm / K). 6. The fine particle according to claim 1, wherein the fine particle of the fine particle dispersion is a fine particle containing one or more kinds of silica fine particles having a shape in which porous fine silica particles, hollow silica fine particles, and primary particles are connected. A method for producing a low refractive index film. The method for producing a low refractive index film according to claim 1, wherein an average primary particle diameter of the fine particles of the fine particle dispersion is 1 nm or more and 100 nm or less. The manufacturing method of the antireflective film characterized by including the manufacturing method of the low-refractive-index film of any one of Claims 1-7.