JP2016153241A - Optical member and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical member capable of preventing a crack or removal of a film even after using to a given substrate for a long period of time, and maintaining a highly efficient antireflection effect.SOLUTION: An optical member at least includes: a layer 2 having a polyimide as a main constituent; and a layer 4 having an uneven structure 5 formed of plate crystal having an aluminum oxide as a main constituent, sequentially laminated. The polyimide includes a silane group via an amide bond at a side chain.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical member having antireflection performance and a method for manufacturing the same, and more specifically, an optical member suitable for stably obtaining high antireflection performance in the long term from the visible region to the near infrared region and its manufacture. Regarding the method.

  It is known that an antireflection structure using a fine periodic structure with a wavelength equal to or smaller than the wavelength in the visible light region exhibits excellent antireflection performance in a wide wavelength region by forming a fine periodic structure with an appropriate pitch and height. ing. As a method for forming a fine periodic structure, coating of a film in which fine particles having a particle diameter of a wavelength or less are dispersed is known. Among these, it is known that a concavo-convex structure made of boehmite of aluminum oxide grown on a substrate can obtain a high antireflection effect. The concavo-convex structure made of boehmite is obtained by subjecting an aluminum oxide film formed by a liquid phase method (sol-gel method) or the like to steam treatment or hot water immersion treatment (see Non-Patent Document 1). However, the glass substrate may be damaged when exposed to water vapor or warm water.

  Then, the effect which suppresses the damage to the glass base material by a water | moisture content or water vapor | steam was found by providing the layer which consists of a solvent soluble polyimide between the base material and the uneven structure which consists of boehmite of aluminum oxide (refer patent document 1). ). However, the layer made of polyimide is difficult to use as it is because it has low affinity and adhesion to other layers including the base material (see Patent Document 2). In particular, when an uneven structure of aluminum oxide is formed via a hot water immersion treatment, peeling occurs between the polyimide layer and the adjacent layer due to strain stress during formation of the unevenness, or cracks occur in the polyimide layer itself or the adjacent layer. May occur.

JP 2008-233880 A JP-A 61-171762

K. Tadanaga, N .; Katata, and T.K. Minami: “Super-Water-Repellent Al 2 O 3 Coating Films with High Transparency,” J. Am. Ceram. Soc. , 80 [4] 1040-42 (1997)

  An aluminum oxide layer having a concavo-convex structure formed by a method of growing boehmite on a base material is simple and has high productivity and excellent optical performance. However, when forming a concavo-convex structure by dipping in warm water, Erosion of base materials such as alkali ions and alkali ions occurs easily. For this reason, a multi-layer structure is used that increases the antireflection performance while suppressing damage to the base material by forming a thin film between the base structure of boehmite and the base material. It causes stress and causes peeling and cracks between the layers.

  The present invention has been made in view of such a background art, and an optical member that does not cause peeling or cracking of the film even during manufacturing or after being used for a long period of time and maintains a high-performance antireflection effect. And it aims at providing the manufacturing method.

  In order to achieve the above object, the present invention provides an optical member configured as follows and a method for manufacturing the same.

  The optical member of the present invention is an optical member in which a laminate having a concavo-convex structure formed from a plate-like crystal containing aluminum oxide as a main component is formed on the outermost surface of a base material, at least one layer of the laminate. Is a layer containing polyimide as a main component, and the polyimide includes a repeating structure represented by the general formula (1) and a structure represented by the general formula (2) in the main chain.

(R1 is a tetravalent organic group, and R2 is a divalent organic group.)

(R3 is a tetravalent organic group, R4 is a phenylene group or a C1-C5 alkylene group, R5 is a hydrogen atom, a linear or branched alkyl group, a phenyl group, or a substrate or other polymer via -Si≡. R6 is a hydrogen atom, a linear or branched alkyl group, or a phenyl group, m is 0 or 1, n is 1 or 2, 2m + n = 4, and X is 1 or more It is an integer of 3 or less.)

Moreover, the manufacturing method of the optical member of the present invention includes:
(1) A step of preparing a polyimide solution by sequentially adding a polyimide having a repeating structure represented by the following general formula (5) and a silane compound represented by the following general formula (6) into an organic solvent, (2 ) A step of spreading the polyimide solution on the base material or a different layer formed on the base material, (3) a step of forming a polyimide thin film by drying or / and baking, and (4) an outermost surface of the base material. It includes a step of forming a concavo-convex structure formed from a plate-like crystal containing aluminum oxide as a main component.

(R15 is a tetravalent organic group, and R16 is a divalent organic group.)

(R17 is an oxygen atom or a sulfur atom, R18 is a phenylene group or a C1-C5 alkylene group, R19 is a hydrogen atom, a C1-C5 linear or branched alkyl group, and R20 is a hydrogen atom, a linear or branched alkyl group. Or a phenyl group, and Z is an integer of 1 or more and 3 or less.)

According to the present invention, it is possible to provide an optical member that is free from cracks, has little unevenness in optical performance, and can stably exhibit a high antireflection effect over a long period of time.
Moreover, according to this invention, the manufacturing method of said optical member can be provided.

It is the schematic which shows one embodiment of the optical member of this invention. It is the schematic which shows one embodiment of the optical member of this invention. It is the schematic which shows one embodiment of the optical member of this invention.

  Hereinafter, the present invention will be described in detail.

  FIG. 1 is a schematic schematic cross-sectional view showing an optical member according to this embodiment. 1, in the optical member of the present invention, a layer 2 composed mainly of polyimide and a layer 3 composed of a fine concavo-convex structure are sequentially laminated on the surface of a substrate 1. A fine concavo-convex structure 4 made of a plate-like crystal composed mainly of aluminum oxide is formed on the outermost surface.

  The laminated body comprised from the layer 2 which has the polyimide 2 of this invention as a main component, and the layer 3 which consists of a fine uneven structure can suppress the reflection of the light which generate | occur | produces on the base material 1 surface. The layer 2 containing polyimide as a main component is a layer composed of polyimide alone or a component other than polyimide and a small amount of polyimide. Components other than polyimide are complementary to polyimide as a main component, and can be dissolved, mixed, and dispersed in polyimide as long as the characteristics are not impaired.

  By providing the layer 2 mainly composed of polyimide between the base material 1 and the layer 3 having a fine concavo-convex structure, the antireflection effect is higher than when the layer 3 having a fine concavo-convex structure is directly formed on the base material 1. Is obtained. Therefore, the film thickness of the layer 2 containing polyimide as a main component is in the range of 10 nm to 150 nm, and is changed in this range in accordance with the refractive index of the substrate. When the film thickness is less than 10 nm, the antireflection effect is not different from the case where there is no layer 2 containing polyimide as a main component. On the other hand, when the film thickness exceeds 150 nm, the antireflection effect is significantly reduced.

  The polyimide which comprises the layer 2 which has a polyimide as a main component is a solvent-soluble polyimide, Comprising: The repeating structure represented by General formula (1) and the structure represented by General formula (2) are included in a principal chain.

(R1 is a tetravalent organic group, and R2 is a divalent organic group.)

(R3 is a tetravalent organic group, R3 is a phenylene group or a C1-C5 alkylene group, R4 is a C1-C5 linear or branched alkyl group, R5 is a hydrogen atom, a linear or branched alkyl group, or phenyl. A group, or a structure bonded to a substrate or another polymer via —Si≡, R 6 is a hydrogen atom, a linear or branched alkyl group, or a phenyl group, m is 0 or 1, and n is 1 or 2 and 2m + n = 4, and X is an integer of 1 to 3.)

  The general formula (1) represents a general polyimide repeating structure in which acid dianhydride sites and diamine sites are alternately linked. On the other hand, the general formula (2) has a structure in which a carbonyl group remaining without becoming an imide ring is bonded to an alkoxysilane group via an amide bond. However, the alkoxyl group on the alkoxysilane group changes to a hydroxyl group by reacting with moisture, the alkoxyl group and the hydroxyl group on the substrate surface react to bond to each other, or the alkoxyl groups react to each other to produce ≡Si—O It can be bonded by -Si≡.

  Since the polyimide having the repeating structure represented by the general formula (1) is composed of an imide ring, an aromatic ring, an aliphatic group, and the like, it has poor affinity and adhesion to a layer made of a different material, particularly an inorganic substance. However, by introducing the structure represented by the general formula (2) into the main chain, an alkoxysilane group or a reactive group thereof is present at the interface between the layer 2 mainly composed of polyimide and the adjacent layer or substrate. be able to. Thereby, it is possible to improve the affinity between the layer 2 containing polyimide as a main component and the adjacent layer or substrate, or to react with the adjacent layer to improve the adhesion.

  The molar amount of the structure represented by the general formula (2) contained in the solvent-soluble polyimide when the repeating structure represented by the general formula (1) contained in the solvent-soluble polyimide is 1 mol is 0.002. More preferably, it is -0.05. When the molar amount of the structure represented by the general formula (2) is less than 0.002, there is not a sufficient number of alkoxysilane groups or reactive groups at the interface with the adjacent layer or substrate, so that the adjacent layer or group The effect of improving the affinity and adhesion with the material cannot be obtained. On the other hand, when it exceeds 0.05, the glass transition point of the layer 2 containing the polyimide of the present invention as a main component, the refractive index is lowered, and the water absorption is increased.

  The solvent-soluble polyimide of the present invention mainly has a repeating structure represented by the general formula (1), and the most general synthesis method is a polyaddition reaction and a dehydration condensation reaction of an acid dianhydride and a diamine ( (Imidation reaction). Therefore, the tetravalent organic group introduced into R1 in the general formula (1) depends on the type of acid dianhydride used during polymerization. In addition, since the general formula (2) is a structure including a carbonyl group that remains without being converted to an imide ring during the imidization reaction, the tetravalent organic group introduced into R3 in the formula is similarly an acid dianhydride. It depends on the type.

  Examples of acid dianhydrides used for the synthesis of polyimide include pyromellitic acid anhydride, 3,3′-biphthalic acid anhydride, 3,4′-biphthalic acid anhydride, 3,3 ′, 4,4 ′. -Benzophenone tetracarboxylic dianhydride, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, 4,4'-oxydiphthalate Aromatic dianhydrides such as acid dianhydrides, meso-butane-1,2,3,4-tetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1, 2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,3,5 , 6-Tetracar Acid dianhydride, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.1] heptane-2,3,5,6-tetra Carboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 4- (2,5-dioxotetrahydrofuran-3-yl ) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, and the like. From the viewpoint of improving the solubility, coatability and transparency of polyimide, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride , Meso-butane-1,2,3,4-tetracarboxylic dianhydride, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2 .1] heptane-2,3,5,6-tetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride is more preferred.

  On the other hand, the divalent organic group introduced into R2 in the general formula (1) is determined by the kind of diamine at the time of polymerization.

  Examples of diamines include m-phenylenediamine, p-phenylenediamine, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, o-tolidine , M-tolidine, 4,4′-diaminobenzophenone, 1,1-bis (4-aminophenyl) cyclohexane, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 1,4-bis (4- Aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-bis (4-aminophenoxy) biphenyl, Bis [4- (4-aminophenoxy) phenyl] sulfone, 4,4′-bis (3-a Nophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] sulfone, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4-amino-3-methylphenyl) fluorene, 9 , 9-bis (4-amino-3-fluorophenyl) fluorene, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2- Aromatic diamines such as bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2′-bis (trifluoromethyl) benzidine, direct 1,4-diaminobutane, 1,5-diaminopentane, etc. Diamine having a chain or branched aliphatic group, 1,3-cyclohexanediamine, 1,4-cyclohexanediame 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 4,4′-methylenebis (aminocyclohexane), 4,4′-methylenebis (1-amino-2-methylcyclohexane) 2,2-bis (4-aminocyclohexyl) propane, 4,4′-bicyclohexylamine, α, α′-bis (4-aminocyclohexyl) -1,4-diisopropylcyclohexane, isophoronediamine, norbornanediamine, adamantane Diamines having an alicyclic structure such as 1,3-diamine and 1,3-bis (aminomethyl) adamantane, 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 1,4-bis (3- Aminopropyldimethylsilyl) benzene, dimethylsilane having amino groups at both ends It includes diorganosiloxane group-containing diamine such as hexane oligomer.

  In particular, 4,4′-methylenebis (aminocyclohexane), 4,4′-bis (3) is highly reactive, and the resulting polyimide has high heat resistance and solubility, and can be controlled in refractive index over a wide range depending on the combination. -Aminophenoxy) biphenyl, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4-amino-3-methylphenyl) fluorene, 9,9-bis (4-amino-3-fluorophenyl) It is more preferable to use fluorene. Moreover, it is more preferable to use diorganosiloxane group containing diamine from a viewpoint of the adhesiveness with respect to inorganic base materials, such as glass, and the implementation | achievement of a lower refractive index.

  Furthermore, it is more preferable that the structure represented by General formula (3) is included in the terminal of the solvent soluble polyimide used for the layer 2 which has a polyimide as a main component.

(R7 is a tetravalent organic group, R8 is a methyl group, an ethyl group, or an isopropyl group, R9 is a phenylene group or a C1-C5 alkylene group, R10 is a hydrogen atom, a C1-C5 linear or branched alkyl group, Or a phenyl group, or a structure bonded to a substrate or another polymer via —Si≡, R 11 is a hydrogen atom, a linear or branched alkyl group, or a phenyl group, y is an integer of 1 to 3, and p Is 0 or 1.)

  The general formula (3) has a structure in which a carbonyl group having an anhydride ring remaining at the terminal during polymerization is bonded to an alkoxysilane group via an amide bond. However, the alkoxyl group on the alkoxysilane group changes to a hydroxyl group by reacting with moisture, the alkoxyl group and the hydroxyl group on the substrate surface react to bond to each other, or the alkoxyl groups react to each other to produce ≡Si—O It can be bonded by -Si≡. By introducing the structure of the general formula (3) at the end, the same effect as that of the general formula (2) can be expected. However, since a sufficient number cannot be introduced only at the end, the adjacent layer can coexist with the general formula (2). It demonstrates the effect of improving affinity and adhesion.

  The molar amount of the structure represented by the general formula (3) contained in the solvent-soluble polyimide when the repeating structure represented by the general formula (1) contained in the solvent-soluble polyimide is 1 mol is 0 to 0. 0.03 and the sum of the molar amounts of the structures of the general formula (2) and the general formula (3) does not exceed 0.05. When the sum of the molar amounts of the structures of the general formula (2) and the general formula (3) exceeds 0.05, the glass transition point of the layer 2 containing the polyimide of the present invention as a main component, the refractive index decreases and the water absorption increases. Invite.

  Moreover, it is more preferable that the structure represented by General formula (4) is included in the terminal of solvent-soluble polyimide.

(R12 is a tetravalent organic group, R13 is a divalent organic group, and R14 is a C1-C3 alkyl group or fluoroalkyl group.)

  The structure represented by the general formula (4) is a structure in which an amino group remaining at the terminal during polymerization is sealed by amidation. If the terminal amino group remains, it causes coloring of the solution and the film, and thus coloring can be suppressed by sealing with amide.

  The tetravalent organic group to be introduced into R7 of the general formula (3) and R12 of the general formula (4) is determined by the kind of acid dianhydride used during the polymerization, similarly to R1 of the general formula (1). On the other hand, the divalent organic group introduced into R13 of the general formula (4) is determined by the kind of diamine used during the polymerization, similarly to R2 of the general formula (1).

  A method for forming the layer 2 mainly composed of polyimide of the present invention will be described.

  First, a solvent-soluble polyimide having an imidation ratio of 96 to 99.9% and having a repeating structure represented by the following general formula (5) and a silane compound represented by the following general formula (6) are sequentially added to the organic solvent. To prepare a polyimide solution. Thereafter, a layer 2 mainly composed of polyimide is formed through a step of spreading the polyimide solution on a base material or a different layer formed on the base material, a step of forming a polyimide thin film by drying or / and baking. .

(R15 is a tetravalent organic group, and R16 is a divalent organic group.)

(R17 is an oxygen atom or a sulfur atom, R18 is a phenylene group or a C1-C5 alkylene group, R19 is a hydrogen atom, a C1-C5 linear or branched alkyl group, and R20 is a hydrogen atom, a linear or branched alkyl group. Or a phenyl group, and Z is an integer of 1 or more and 3 or less.)

  The repeating structure represented by the general formula (5) is the same structure as the repeating structure represented by the general formula (1). Therefore, in order to synthesize a solvent-soluble polyimide having a repeating structure represented by the general formula (5), first, the acid dianhydride and diamine are reacted in a solvent to obtain a polyamic acid solution, and then imidization is performed. Do.

  The solvent used for the synthesis of the polyimide may be any solvent in which polyamic acid and polyimide are dissolved, and in general, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, etc. An aprotic polar solvent is used.

  The imidization is a method in which polyamic acid is dehydrated and closed and converted to polyimide. For the imidization, a chemical imidization method in which a tertiary amine such as pyridine or triethylamine and a dehydration catalyst such as acetic anhydride or trifluoroacetic anhydride are added to the polyamic acid solution and heated at 20 to 120 ° C., and a polyamic acid solution There is thermal imidization in which xylene is added to azeotropically at 150 ° C. or higher. The former chemical imidization method is preferred in order to obtain a transparent and less colored polyimide having a high imidization rate. In addition, when chemical imidization is performed, the terminal amino group of the polyimide is amidated by a dehydration catalyst.

  The solution after the polyimide synthesis may be used as it is, but when used for optical applications, it is preferable to obtain a polyimide powder by reprecipitation once in a poor solvent. In particular, in order to remove various chemicals and unreacted monomers used in chemical imidization, the polyimide powder obtained by reprecipitation is repeatedly washed with alcohol and filtered. Finally, it is dried at 20 ° C. or more and 200 ° C. or less at normal pressure or reduced pressure. The imidation rate of the obtained polyimide is preferably 96% or more and 99.8% or less. If the imidization rate is less than 96%, the water absorption rate of the polyimide increases and the refractive index also decreases. When the imidization ratio exceeds 99.8%, the silane compound hardly reacts with the polyimide, and the effect of improving the affinity and adhesion with the adjacent layer or substrate cannot be obtained.

  Subsequently, a silane compound is added to the polyimide solution and reacted at 20 ° C. or higher and 60 ° C. or lower. The aminosilane compound is a compound represented by the general formula (6) and has a functional group such as isocyanate or thioisocyanate. These functional groups react with carbonyl groups remaining in the polyimide without becoming imide rings to form amide bonds. As a result, a silane group can be introduced into the side chain of the polyimide through the structure represented by the general formula (2). Moreover, the structure represented by General formula (7) can be formed in the terminal of a polyimide.

(R21 is a tetravalent organic group, R22 is a divalent organic group, and R23 is a C1-C3 alkyl group or fluoroalkyl group.)

  In addition, the silane group can be hydrolyzed in the solution in order to further improve the affinity and adhesion with the adjacent layer or substrate. Specifically, a method of adding a small amount of water after reacting a silane compound with polyimide is preferable. The amount of water that can be added is 1 mol% or less with respect to 100 mol% of the solution. If it is added more than that, the hydrolysis of the silane group proceeds too much, so that the solubility of the polyimide is lowered, and the possibility that the deposition and film forming properties are lowered is increased.

  The polyimide solution having a side chain introduced with a silane group is applied on the substrate, that is, in direct contact with the substrate. Alternatively, it is applied on a thin film provided on the substrate, that is, in direct contact with the thin film. When applied so as to come into contact with the base material, the adhesion with the base material is improved, and it is possible to prevent peeling cracks and the like, and to elute base material components such as alkali ions, even after manufacturing or after long-term use. And a high-performance antireflection effect is maintained. As a coating method, for example, known coating means such as a dipping method, a spin coating method, a spray method, a printing method, a flow coating method, and a combination thereof can be appropriately employed. When coating on a curved surface such as a lens surface, spin coating is preferred from the viewpoint of film thickness uniformity.

  Furthermore, the layer 2 which has a polyimide as a main component is formed by drying or baking the solution containing the apply | coated polyimide at 100 to 250 degreeC. Drying and / or calcination of the polyimide-containing solution is mainly performed for removing the solvent, and it is preferable to perform heating for about 5 minutes to 2 hours. As a heating method, it is necessary to appropriately select a hot air circulation oven, a muffle furnace, light such as infrared rays and microwaves, radiation or electromagnetic wave irradiation.

  The layer 2 containing polyimide as a main component can be mixed with components other than polyimide to such an extent that the optical properties, transparency, heat resistance and water resistance of the polyimide are not impaired. When mixing components other than polyimide, the components other than polyimide that can be mixed when the entire polyimide is 100 parts by weight are less than 20 parts by weight. When it mixes more, transparency, film | membrane intensity | strength, and the uniformity of a film thickness may be impaired.

For the purpose of improving the solvent resistance of the layer 2 containing polyimide as a main component, a heat or photo-curable resin such as an epoxy resin, a melamine resin, or an acrylic resin, or a crosslinking agent can be mixed. In order to adjust the refractive index and increase the hardness of the film, a small amount of inorganic fine particles such as SiO ₂ , TiO ₂ , ZrO ₂ , SiO ₂ , ZnO, MgO, Al ₂ O ₃ can be mixed.

  The layer 3 having a fine concavo-convex structure formed on the layer 2 mainly composed of polyimide of the present invention has a fine concavo-convex structure 4 formed on the outermost surface thereof. The fine concavo-convex structure 4 is a plate-like crystal of aluminum oxide. The aluminum crystal plate-like crystal is formed by immersing a film mainly composed of aluminum oxide in warm water, so that the surface layer of the aluminum oxide film is subjected to a peptizing action or the like. This refers to plate-like crystals that precipitate and grow on the surface of the film.

  The layer 3 having a fine concavo-convex structure is preferably a layer whose refractive index continuously increases from the surface layer side toward the base material side, and the refractive index continuously increases from the surface layer side toward the base material side. As a result, the effect of reducing the reflectivity is greater than when layers having a high refractive index are stacked in order from the surface layer side.

The layer 3 having a fine concavo-convex structure is formed of a plate-like crystal mainly composed of aluminum oxide, aluminum hydroxide, or aluminum oxide hydrate. A particularly preferred plate crystal is boehmite. Further, by arranging these plate crystals, the end portions form a fine concavo-convex structure 4, so the plate crystals are selectively used to increase the height of the fine concavo-convex and narrow the interval. It is arranged at a specific angle with respect to the surface of the substrate. In the present application, aluminum oxide, aluminum hydroxide, or aluminum oxide hydrate is referred to as aluminum oxide. In addition, aluminum oxide alone or one or more oxide layers containing any of ZrO ₂ , SiO ₂ , TiO ₂ , ZnO, and MgO and containing 70 mol% or more of aluminum oxide are mainly composed of aluminum oxide. It shall be called a layer.

  The case where the surface of the base material 1 is a flat surface such as a flat plate, a film or a sheet is shown in FIG. The plate crystal has an average angle of 45 ° to 90 °, preferably 60 ° to 90 °, with respect to the surface of the substrate, that is, the angle θ1 between the inclination direction 5 of the plate crystal and the substrate surface. It is desirable to arrange so that.

  Moreover, the case where the surface of the base material 1 has a two-dimensional or three-dimensional curved surface is shown in FIG. The plate crystal has an average angle θ2 of 45 ° or more and 90 ° or less, preferably 60 ° or more and 90 ° with respect to the surface of the substrate, that is, between the inclination direction 6 of the plate crystal and the tangent 7 of the substrate surface. It is desirable to arrange it so that it is below °. Note that the values of the angles θ1 and θ2 may exceed 90 ° depending on the inclination of the plate-like crystal. In this case, the values are measured to be 90 ° or less.

  The layer thickness of the layer 3 having a fine concavo-convex structure is preferably 20 nm or more and 1000 nm or less, and more preferably 50 nm or more and 1000 nm or less. When the layer thickness for forming the unevenness is 20 nm or more and 1000 nm or less, the antireflection performance by the fine uneven structure is effective, and the mechanical strength of the uneven structure is eliminated, and the manufacturing cost of the fine uneven structure is advantageous. Become. Moreover, when the layer thickness is 50 nm or more and 1000 nm or less, the antireflection performance is further improved, which is more preferable.

  The surface density of the fine irregularities of the present invention is also important, and the average surface roughness Ra ′ value obtained by expanding the corresponding centerline average roughness is 5 nm or more, more preferably 10 nm or more, more preferably 15 nm or more and 100 nm or less, The surface area ratio Sr is 1.1 or more. More preferably, it is 1.15 or more, More preferably, it is 1.2 or more and 3.5 or less.

  One of the evaluation methods of the obtained fine concavo-convex structure is observation of the surface of the fine concavo-convex structure with a scanning probe microscope, and the average surface roughness Ra ′ obtained by extending the center line average roughness Ra of the film by the observation. The value and the surface area ratio Sr are determined. That is, the average surface roughness Ra ′ value (nm) is obtained by applying the centerline average roughness Ra defined in JIS B 0601 to the measurement surface and extending it three-dimensionally. It is expressed as “average value of absolute values of deviations up to” and is given by the following equation (24).

Ra ′: average surface roughness value (nm),
S ₀ : Area when the measurement surface is ideally flat, | X _R −X _L | × | Y _T −Y _B |, F (X, Y): High at the measurement point (X, Y) X is the X coordinate, Y is the Y coordinate,
X _L to X _R : X coordinate range of the measurement surface,
Y _B to Y _T : Y coordinate range of the measurement surface,
Z ₀ : Average height in the measurement plane.

The surface area ratio Sr is Sr = S / S ₀ [S ₀ : Area when the measurement surface is ideally flat. S: Surface area of the actual measurement surface. ]. The actual surface area of the measurement surface is obtained as follows. First, it is divided into minute triangles composed of the three closest data points (A, B, C), and then the area ΔS of each minute triangle is obtained using a vector product. ΔS (ΔABC) = [s (s−AB) (s−BC) (s−AC)] 0.5 [where AB, BC, and AC are the lengths of each side, and s≡0.5 ( AB + BC + AC)], and the sum of ΔS is the surface area S to be obtained. When the surface density of the fine irregularities is Ra ′ is 5 nm or more and Sr is 1.1 or more, antireflection by the irregular structure can be expressed. If Ra ′ is 10 nm or more and Sr is 1.15 or more, the antireflection effect is higher than that of the former. When Ra ′ is 15 nm or more and Sr is 1.2 or more, the performance can withstand actual use. However, when Ra ′ is 100 nm or more and Sr is 3.5 or more, the effect of scattering by the concavo-convex structure is superior to the antireflection effect, and sufficient antireflection performance cannot be obtained.

  In the case where the layer 3 having a fine concavo-convex structure in the present invention contains aluminum oxide as a main component, the layer 2 containing polyimide as a main component contains either a film of metal Al alone or metal Al and metal Zn or metal Mg. A metal film is formed. Then, it is formed by being immersed in warm water of 50 ° C. or higher and / or exposed to water vapor. At this time, the concavo-convex structure 4 is formed on the metal surface by hydration, dissolution, and reprecipitation. On the other hand, a layer mainly composed of aluminum oxide is formed on the layer 2 composed mainly of an organic resin, and the fine concavo-convex structure 4 is deposited on the surface by being immersed in warm water or exposed to water vapor as described above. Can do. The layer containing aluminum oxide as a main component can be formed by known CVD, PVD vapor phase method, liquid phase method such as sol-gel method, hydrothermal synthesis using an inorganic salt, or the like. In such a method of providing a plate-like crystal of aluminum oxide, an amorphous aluminum oxide layer may remain below the uneven structure 4 in the layer 3 having a fine uneven structure.

  Since a uniform antireflection layer can be formed on a large area or non-planar substrate, a gel film formed by applying a sol-gel coating solution containing aluminum oxide is treated with warm water to produce alumina plate crystals. The method of growing is preferable.

As a raw material for a gel film obtained from a sol-gel coating solution containing aluminum oxide, an Al compound and / or at least one compound of each of Zr, Si, Ti, Zn, and Mg are used together with the Al compound. As raw materials for Al ₂ O ₃ , ZrO ₂ , SiO ₂ , TiO ₂ , ZnO, and MgO, each metal alkoxide, salt compound such as chloride and nitrate can be used. From the viewpoint of film forming properties, it is particularly preferable to use a metal alkoxide as a ZrO ₂ , SiO ₂ , or TiO ₂ raw material.

  Examples of the aluminum compound include aluminum ethoxide, aluminum isopropoxide, aluminum-n-butoxide, aluminum-sec-butoxide, aluminum-tert-butoxide, and aluminum acetylacetonate. Moreover, these oligomers, aluminum nitrate, aluminum chloride, aluminum acetate, aluminum phosphate, aluminum sulfate, aluminum hydroxide, etc. are mentioned.

  Specific examples of the zirconium alkoxide include the following. Zirconium tetramethoxide, zirconium tetraethoxide, zirconium tetra n-propoxide, zirconium tetraisopropoxide, zirconium tetra n-butoxide, zirconium tetra t-butoxide and the like.

As the silicon alkoxide, various compounds represented by the general formula Si (OR) ₄ can be used. R may be the same or different lower alkyl group such as methyl group, ethyl group, propyl group, isopropyl group, butyl group and isobutyl group.

  Examples of the titanium alkoxide include tetramethoxy titanium, tetraethoxy titanium, tetra n-propoxy titanium, tetraisopropoxy titanium, tetra n-butoxy titanium, and tetraisobutoxy titanium.

  Examples of the zinc compound include zinc acetate, zinc chloride, zinc nitrate, zinc stearate, zinc oleate, and zinc salicylate, with zinc acetate and zinc chloride being particularly preferred.

  Examples of the magnesium compound include magnesium alkoxides such as dimethoxy magnesium, diethoxy magnesium, dipropoxy magnesium and dibutoxy magnesium, magnesium acetylacetonate, magnesium chloride and the like.

  Any organic solvent may be used as long as it does not cause the alkoxide or the like to gel. For example, methanol, ethanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-2-butanol , Isoamyl alcohol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2,4-dimethylpentanol, 2-ethyl- Alcohols such as 1-butanol, ethylene glycol, or methyl cellosolve, ethyl cellosolve, propyl cellosolve, isopropyl cellosolve, butyl cellosolve, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-propoxy-2-propanol, Such Glycols or glycol ethers. Various aliphatic or alicyclic hydrocarbons such as n-hexane, n-octane, cyclohexane, cyclopentane, and cyclooctane. Various aromatic hydrocarbons such as toluene, xylene, and ethylbenzene. Various esters such as ethyl formate, ethyl acetate, n-butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate. Various ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone and cyclohexanone. Various ethers such as dimethoxyethane, tetrahydrofuran, dioxane, diisopropyl ether, dibutyl ether. Various chlorinated hydrocarbons such as chloroform, methylene chloride, carbon tetrachloride, tetrachloroethane. Examples include aprotic polar solvents such as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and ethylene carbonate. From the viewpoint of the stability of the solution, it is preferable to use alcohols among the various solvents described above.

  In the case of using an alkoxide raw material, aluminum, zirconium, and titanium alkoxides are particularly highly reactive with water, and are rapidly hydrolyzed by the addition of moisture and water in the air, resulting in cloudiness and precipitation of the solution. In addition, aluminum salt compounds, zinc salt compounds, and magnesium salt compounds are difficult to dissolve with only an organic solvent, and the stability of the solution is low. In order to prevent these, it is preferable to add a stabilizer to stabilize the solution.

  Examples of the stabilizer include acetylacetone, dipyrobaylmethane, trifluoroacetylacetone, hexafluoroacetylacetone, benzoylacetone, dibenzoylmethane, 3-methyl-2,4-pentanedione, 3-ethyl-2,4-pentane. Β-diketone compounds such as dione, 3-butyl-2,4-pentanedione, 3-phenyl-2,4-pentanedione, and 3-chloroacetylacetone. Methyl acetoacetate, ethyl acetoacetate, allyl acetoacetate, benzyl acetoacetate, acetoacetate-iso-propyl, acetoacetate-tert-butyl, acetoacetate-iso-butyl, acetoacetate-2-methoxyethyl, 3-keto-n Β-ketoester compounds such as methyl valeric acid. Furthermore, alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine can be exemplified. The addition amount of the stabilizer is preferably about 1 in terms of molar ratio to the alkoxide or salt compound. Further, after the addition of the stabilizer, it is preferable to add a catalyst for the purpose of promoting a part of the reaction in order to form an appropriate precursor. Examples of the catalyst include nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, ammonia and the like. As a method of forming a film using the sol-gel coating solution, for example, a known coating means such as a dipping method, a spin coating method, a spray method, a printing method, a flow coating method, and a combination thereof may be appropriately employed. it can.

  After applying the sol-gel coating solution, it is preferable to perform heat treatment in the range of 100 ° C. or higher and 230 ° C. or lower. The higher the heat treatment temperature, the more easily the film becomes denser. However, when the heat treatment temperature exceeds 230 ° C., the substrate is damaged such as deformation. More preferably, it is 120 degreeC or more and 200 degrees C or less. The heating time depends on the heating temperature, but is preferably 10 minutes or longer.

  The gel film that has been dried or heat-treated is immersed in warm water, thereby precipitating plate crystals mainly composed of aluminum oxide to form an uneven surface shape on the outermost surface. By soaking in warm water, the surface layer of the gel film containing aluminum oxide is subjected to peptization and the like, and some components are eluted. Due to the difference in solubility of various hydroxides in warm water, plate crystals mainly composed of aluminum oxide are precipitated and grown on the surface layer of the gel film. In addition, it is preferable that the temperature of warm water shall be 40 to 100 degreeC. The hot water treatment time is about 5 minutes to 24 hours.

In hot water treatment of a gel film in which an oxide such as TiO ₂ , ZrO ₂ , SiO ₂ , ZnO, or MgO is added as a different component to a film containing aluminum oxide as a main component, the difference in solubility of each component in hot water is used to crystallize the film. Is going on. Therefore, unlike the hot water treatment of an aluminum oxide single component film, the size of the plate crystal can be controlled over a wide range by changing the composition of the inorganic component. As a result, it is possible to control the concavo-convex shape formed by the plate crystal over the wide range. Further, when ZnO is used as a subcomponent, it can be co-deposited with aluminum oxide, so that the refractive index can be controlled over a wider range, and excellent antireflection performance can be realized.

  Examples of the substrate 1 used in the present invention include glass, resin, glass mirror, resin mirror, and the like. The following are mentioned as a typical thing of a resin base material. Films of thermoplastic resins such as polyester, triacetyl cellulose, cellulose acetate, polyethylene terephthalate, polypropylene, polystyrene, polycarbonate, polysulfone, polyacrylate, polymethacrylate, ABS resin, polyphenylene oxide, polyurethane, polyethylene, polycycloolefin, polyvinyl chloride And molded products. Moreover, the crosslinked film obtained from various thermosetting resins, such as unsaturated polyester resin, a phenol resin, bridge | crosslinking-type polyurethane, a bridge | crosslinking-type acrylic resin, a bridge | crosslinking-type saturated polyester resin, the bridge | crosslinking molded article, etc. are mentioned. Specific examples of the glass include alkali-free glass and alumina silicate glass. The substrate used in the present invention may be any substrate that can be finally shaped according to the purpose of use, such as a flat plate, film or sheet, and having a two-dimensional or three-dimensional curved surface. Also good. The thickness can be appropriately determined and is generally 5 mm or less, but is not limited thereto.

  In addition to the layers described above, the optical member of the present invention can further include layers for imparting various functions. For example, one or more layers other than polyimide are provided between the base material 1 and the layer 2 containing polyimide as a main component or / and between the layer 2 containing polyimide as a main component and the layer 3 having a fine concavo-convex structure. Thus, the antireflection performance can be enhanced. In order to improve the film hardness, a hard coat layer is provided on a layer having a fine concavo-convex structure, or a water-repellent film layer such as fluoroalkylsilane or alkylsilane is provided for the purpose of preventing the adhesion of dirt. be able to. On the other hand, an adhesive layer or a primer layer can be provided in order to improve the adhesion between the substrate and the layer containing polyimide as a main component.

  Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited to such examples. The optical film having fine irregularities on the surface obtained in each example and comparative example was evaluated by the following method.

(1) Synthesis of polyimides 1 to 10 A total of 0.012 mol of diamine (1), diamine (2) and diamine (3) were dissolved in N, N-dimethylacetamide (hereinafter abbreviated as DMAc). While cooling this diamine solution with water, 0.012 mol of acid dianhydride was added. The amount of DMAc was used such that the total mass of diamine and acid dianhydride was 20% by weight. This solution was stirred at room temperature for 15 hours to conduct a polymerization reaction. Furthermore, after adjusting to 8 wt% by dilution with DMAc, 7.4 ml of pyridine and 3.8 ml of acetic anhydride were added and stirred at room temperature for 1 hour. Furthermore, it stirred for 4 hours, heating at 50-80 degreeC with an oil bath. The polymer solution was reprecipitated in methanol and the polymer was taken out, and then washed several times in methanol. After vacuum drying at 100 ° C., a white to pale yellow powdery polyimide was obtained. ^The residual amount of carboxyl groups was measured from the ¹ H-NMR spectrum, and the imidization rate was determined. The composition table of polyimides 1 to 10 is shown in Table 1.

(2) Preparation of polyimide solutions 1 to 23 2.0 g of polyimide 1 to 8 powder was added to 96 to 98 g of a mixed solvent of cyclopentanone / cyclohexanone and stirred at room temperature for complete dissolution. 0.02 to 0.1 g of various silane compounds were added and stirred at 23 to 50 ° C. for 2 hours. Polyimide solutions 1 to 23 were prepared by adding 0.2 g of water and stirring for 1 hour. The composition tables of polyimide solutions 1 to 23 are shown in Table 2.

(3) Preparation of aluminum oxide (alumina (Al ₂ O ₃ )) sol 22.2 g of Al (O-sec-Bu) 3, 5.86 g of 3-oxobutanoic acid ethyl ester and 4-methyl-2-pentanol Were mixed and stirred until uniform. 1.62 g of 0.01 M dilute hydrochloric acid is dissolved in a mixed solvent of 4-methyl-2-pentanol / 1-ethoxy-2-propanol, and then slowly added to the solution of Al (O-sec-Bu) 3 described above. Stir for a while. The solvent was finally adjusted to be a mixed solvent of 49.3 g of 4-methyl-2-pentanol and 21.1 g of 1-ethoxy-2-propanol. Further, an aluminum oxide precursor sol was prepared by stirring in an oil bath at 120 ° C. for 3 hours or more.

(4) Cleaning of base material Various glass base materials having a size of about φ30 mm and a thickness of about 2 mm polished on one side were ultrasonically cleaned with an alkaline detergent and IPA and then dried in an oven.

(5) Reflectance measurement Using an absolute reflectance measuring device (USPM-RU, manufactured by Olympus), reflectance measurement was performed at an incident angle of 0 ° in the range of 400 nm to 700 nm. The average reflectance of 400 nm to 700 nm was defined as the average reflectance.

(6) Measurement of film thickness and refractive index Using a spectroscopic ellipsometer (VASE, manufactured by JA Woollam Japan), the wavelength was measured from 380 nm to 800 nm.

(7) Surface observation of substrate The substrate surface was subjected to Pd / Pt treatment, and surface observation was performed at an acceleration voltage of 2 kV using FE-SEM (S-4800, manufactured by Hitachi High-Tech).

(Examples 1-4)
An appropriate amount of polyimide solutions 1 to 4 were dropped onto the polished surface of the glass substrate A having nd = 1.762 and νd = 26.5 containing TiO 2 as a main component, and spin coating was performed at 4000 rpm. This substrate was dried at 200 ° C. for 60 minutes, and polyimides 1-4 represented by the following general formulas (8) to (11) were converted to 3- (triethoxysilyl) propyl isocyanate represented by the following general formula (12). A substrate on which a modified polyimide film was formed was obtained. The film thickness and refractive index of the polyimide film were measured using ellipsometry.

  An appropriate amount of aluminum oxide precursor sol is dropped on the surface with the polyimide film, spin-coated at 4000 rpm, and then baked in a hot air circulating oven at 200 ° C. for 120 minutes to form an amorphous aluminum oxide film on the polyimide film. Coated.

  Next, after being immersed in warm water of 75 ° C. for 20 minutes, it was dried at 60 ° C. for 15 minutes.

  When the FE-SEM observation of the obtained film surface was performed, a fine concavo-convex structure in which plate crystals mainly composed of aluminum oxide were randomly and intricately complicated was observed.

  Next, the absolute reflectance of the optical film on the glass substrate A was measured to obtain a glass substrate with an antireflection film having an average reflectance of 400 to 700 nm of 0.08%. The film was not peeled off, cracked or colored.

(Examples 5 to 9)
Instead of the glass substrate A, a glass substrate B having nd = 1.847 and νd = 23.8 having TiO2 as a main component was used, and polyimide solutions 5-9 were used instead of the polyimide solutions 1-4. Except that, the same operations as in Examples 1 to 4 were performed.

  Polyimide 5 represented by the following general formula (13) on the glass substrate B is 3- (triethoxysilyl) propyl isocyanate or 3- (trimethoxysilyl) propyl isocyanate represented by the following general formula (14) The polyimide 5 film | membrane modified by was formed. Although the kind, addition amount, and addition conditions of the silane compound were changed, there was no significant difference in the film thickness and refractive index of the polyimide 5 film.

  When a plate-like crystal composed mainly of aluminum oxide was formed on the polyimide 5 film, a glass substrate with an antireflection film having an average reflectance of 400 to 700 nm of 0.07 to 0.1% was obtained. The film was not peeled off, cracked or colored.

(Example 10)
A glass substrate B having nd = 1.847 and νd = 23.8 having TiO2 as a main component instead of the glass substrate A was used, and the polyimide solution 10 was used instead of the polyimide solutions 1 to 4. The same operation as in Examples 1 to 4 was performed.

  A polyimide 6 film in which polyimide 6 represented by the following general formula (15) was modified with 3- (triethoxysilyl) propyl isocyanate on glass substrate B was formed. When a plate-like crystal composed mainly of aluminum oxide was formed on the polyimide 6 film, a glass substrate with an antireflection film having an average reflectance of 400 to 700 nm of 0.08% was obtained. Although the reflectance was partially uneven, no peeling, cracking or coloring of the film was observed.

(Examples 11, 12, and 13)
Instead of the glass substrate A, a glass substrate B having nd = 1.847 and νd = 23.8 having TiO2 as a main component was used, and the polyimide solution 11, 12 or 13 was used instead of the polyimide solutions 1-4. The same operation as in Examples 1 to 4 was performed except that it was used.

  Polyimides 7, 8, and 9 in which polyimides 7, 8, and 9 respectively represented by the following general formulas (16), (17), and (18) are modified with 3- (triethoxysilyl) propyl isocyanate on the glass substrate B A film was formed. When an optical film was formed on the polyimide film in the order of plate crystals mainly composed of aluminum oxide, a glass substrate with an antireflection film having an average reflectance of 400 to 700 nm of 0.07 to 0.1% was obtained. . The film was not peeled off, cracked or colored.

(Example 14)
A glass substrate C having nd = 1.728 and νd = 28.5 containing TiO2 as a main component instead of the glass substrate A was used, and the polyimide solution 14 was used instead of the polyimide solutions 1 to 4. The same operation as in Examples 1 to 4 was performed.

  A polyimide 10 film in which polyimide 10 represented by the following general formula (19) was modified with 3- (triethoxysilyl) propyl isocyanate on glass substrate C was formed. When it formed in order of the plate-like crystal which has aluminum oxide as a main component on the polyimide 10 film | membrane, the glass substrate with an antireflection film whose average reflectance of 400-700 nm is 0.08% was obtained. The film was not peeled off, cracked or colored.

(Comparative Example 1)
The same operation as in Examples 1 to 4 was performed except that the polyimide solution 15 was used instead of the polyimide solutions 1 to 4.

  An unmodified polyimide 4 film was formed on the glass substrate A. However, cracks occurred in some of the samples at the stage of immersing in warm water to form plate crystals mainly composed of aluminum oxide, and partial peeling was observed between the glass substrate A and the polyimide 4 film. The average reflectance at 400 to 700 nm of the part not peeled was 0.08%.

(Comparative Examples 2 and 3)
Instead of the glass substrate A, a glass substrate B having nd = 1.847 and νd = 23.8 containing TiO2 as a main component was used, and polyimide solutions 16 and 17 were used instead of the polyimide solutions 1 to 4. Except that, the same operations as in Examples 1 to 4 were performed.

  An unmodified polyimide 5 or 7 film was formed on the glass substrate B. However, cracks occurred in some of the samples at the stage of immersion in warm water to form plate crystals mainly composed of aluminum oxide, and partial peeling was observed between the glass substrate B and the polyimide film. The average reflectance at 400 to 700 nm of the part not peeled was 0.07 to 0.1%.

(Comparative Example 4)
A glass substrate C having nd = 1.728 and νd = 28.5 containing TiO2 as a main component in place of the glass substrate A was used, and a polyimide solution 18 was used instead of the polyimide solutions 1 to 4. The same operation as in Examples 1 to 4 was performed.

  An unmodified polyimide 4 film was formed on the glass substrate C. However, cracks occurred in some of the samples at the stage of immersion in warm water to form plate crystals mainly composed of aluminum oxide, and partial peeling was observed between the glass substrate C and the polyimide 10 film. The average reflectance at 400 to 700 nm of the part not peeled was 0.08%.

(Comparative Example 5)
A glass substrate B of nd = 1.847 and νd = 23.8, mainly composed of cleaned TiO 2, was used instead of the glass substrate A, and the polyimide solution 19 was used instead of the polyimide solutions 1 to 4. The same operation as in Examples 1 to 4 was performed.

  On the glass substrate B, a polyimide 5 film modified with 0.1 part by weight of 3- (triethoxysilyl) propyl isocyanate was formed. However, cracks occurred at the stage of forming plate crystals mainly composed of aluminum oxide by immersion in warm water. The average reflectance of 400 to 700 nm in the portion where no crack was generated was 0.08%.

(Comparative Examples 6-9)
Instead of the glass substrate A, a glass substrate B having nd = 1.847 and νd = 23.8 containing TiO2 as a main component was used, and polyimide solutions 20-23 were used instead of the polyimide solutions 1-4. Except that, the same operations as in Examples 1 to 4 were performed.

  A polyimide 5 film containing a silane compound represented by the general formulas (20) to (23) having no isocyanate group was formed on the glass substrate B. However, in the polyimide solution 19 containing 3-aminopropyltriethoxysilane, thickening and yellowing were observed from the time of preparation of the solution, and the polyimide 5 film obtained therefrom was also confirmed to be thick and colored yellow. When an optical film was formed in the order of a plate-like crystal composed mainly of polyimide and aluminum oxide, the average reflectance at 400 to 700 nm was 0.15%.

  On the other hand, when other polyimide solutions are used, cracks are generated at the stage of forming plate crystals mainly composed of aluminum oxide by immersion in warm water, and partly between the glass substrate B and the polyimide film. Peeling was observed. The average reflectance at 400 to 700 nm of the portion where cracks and peeling did not occur was 0.07%.

  The optical member of the present invention can correspond to a transparent base material having an arbitrary refractive index, exhibits an excellent antireflection effect for visible light, and has long-term weather resistance. Therefore, a word processor, a computer, a television, Various displays such as plasma display panels. Optical members such as polarizing plates used in liquid crystal display devices, sunglasses lenses made of various optical glass materials and transparent plastics, prescription eyeglass lenses, camera finder lenses, prisms, fly-eye lenses, toric lenses, various optical filters, sensors, and the like. Furthermore, a photographing optical system using them, an observation optical system such as binoculars, and a projection optical system used for a liquid crystal projector or the like. Various optical lenses such as scanning optical systems used in laser beam printers. It can be used for optical members such as covers of various instruments, window glass of automobiles, trains and the like.

DESCRIPTION OF SYMBOLS 1 Base material 2 Layer which has polyimide as a main component 3 Layer which consists of fine uneven structure 4 Fine uneven structure 5 Inclination direction of plate crystal 6 Inclination direction of plate crystal 7 Tangent of substrate surface

The optical member of the present invention is an optical member in which a laminated body having a concavo-convex structure formed of a plate crystal mainly composed of aluminum oxide is formed on a base material, and at least one layer of the laminated body is mainly made of polyimide. It is a layer used as a component, and the polyimide includes a structure represented by general formula (1) , general formula (2) and general formula ( 3 ) in the main chain.

(R ₁ is a tetravalent organic group, and R ₂₁ is a divalent organic group.)

(R ₁ is a tetravalent organic group, and R ₂₂ is a divalent organic group.)

(R3 is a tetravalent organic group, R4 is a phenylene group or a C1-C5 alkylene group, R5 is a hydrogen atom, a linear or branched alkyl group, a phenyl group, or a substrate or other polymer via -Si≡. R6 is a hydrogen atom, a linear or branched alkyl group, or a phenyl group, m is 0 or 1, n is 1 or 2, 2m + 2 n = 4, and X is It is an integer from 1 to 3.)

Moreover, the manufacturing method of the optical member of the present invention includes:
(1) A polyimide having a structure represented by the following general formula ( 20 ) and a structure represented by the following general formula (21) and a silane compound represented by the following general formula ( 22 ) are sequentially added to the organic solvent. A step of preparing a polyimide solution, (2) a step of spreading the polyimide solution on a substrate or a different layer formed on the substrate, and (3) a step of forming a polyimide thin film by drying or / and firing. (4) It includes a step of forming a concavo-convex structure formed from a plate-like crystal containing aluminum oxide as a main component.

(R ₁₅ is a tetravalent organic group, and R ₁₆₁ is a divalent organic group.)

(R ₁₅ is a tetravalent organic group, and R ₁₆₂ is a divalent organic group.)

Claims (9)

In an optical member in which a laminate having a concavo-convex structure formed from a plate-like crystal containing aluminum oxide as a main component is formed on the outermost surface of a substrate, at least one layer of the laminate is a layer containing polyimide as a main component And the polyimide contains a repeating structure represented by the general formula (1) and a structure represented by the general formula (2) in the main chain.

(R1 is a tetravalent organic group, and R2 is a divalent organic group.)

(R3 is a tetravalent organic group, R4 is a phenylene group or a C1-C5 alkylene group, R5 is a hydrogen atom, a linear or branched alkyl group, a phenyl group, or a substrate or other polymer via -Si≡. R6 is a hydrogen atom, a linear or branched alkyl group, or a phenyl group, m is 0 or 1, n is 1 or 2, 2m + n = 4, and X is 1 or more An integer of 3 or less.)   The molar amount of the structure represented by the general formula (2) contained in the polyimide when the repeating structure represented by the general formula (1) contained in the polyimide is 1 mol is 0.002 to .0. The optical member according to claim 1, wherein the optical member is 05. The optical member according to claim 1, comprising a structure represented by the general formula (3) at an end of the polyimide.

(R7 is a tetravalent organic group, R8 is a methyl group, an ethyl group, or an isopropyl group, R9 is a phenylene group or a C1-C5 alkylene group, R10 is a hydrogen atom, a C1-C5 linear or branched alkyl group, Or a phenyl group, or a structure bonded to a substrate or another polymer via —Si≡, R 11 is a hydrogen atom, a linear or branched alkyl group, or a phenyl group, y is an integer of 1 to 3, and p Is 0 or 1.) The optical member according to any one of claims 1 to 3, wherein a structure represented by the general formula (4) is included at a terminal of the polyimide.

(R12 is a tetravalent organic group, R13 is a divalent organic group, and R14 is a C1-C3 alkyl group or fluoroalkyl group.)   5. The optical member according to claim 1, wherein the layer mainly composed of polyimide has a thickness of 10 nm to 150 nm.   The optical member according to claim 1, wherein the polyimide-based layer is in direct contact with the substrate. In the method for manufacturing an optical member,
(1) A step of preparing a polyimide solution by sequentially adding a polyimide having a repeating structure represented by the following general formula (5) and a silane compound represented by the following general formula (6) into an organic solvent, (2 ) A step of spreading the polyimide solution on the base material or a different layer formed on the base material, (3) a step of forming a polyimide thin film by drying or / and baking, and (4) an outermost surface of the base material. A method for producing an optical member, comprising a step of forming a concavo-convex structure formed from a plate-like crystal composed mainly of aluminum oxide.

(R15 is a tetravalent organic group, and R16 is a divalent organic group.)

(R17 is an oxygen atom or a sulfur atom, R18 is a phenylene group or a C1-C5 alkylene group, R19 is a hydrogen atom, a C1-C5 linear or branched alkyl group, and R20 is a hydrogen atom, a linear or branched alkyl group. Or a phenyl group, and Z is an integer of 1 or more and 3 or less.)   The method for producing an optical member according to claim 7, wherein the polyimide has an imidization ratio of 96 to 99.9%. The method for producing an optical member according to claim 7 or 8, comprising a structure represented by the general formula (7) at an end of the polyimide.

(R21 is a tetravalent organic group, R22 is a divalent organic group, and R23 is a C1-C3 alkyl group or fluoroalkyl group.)