JP6961775B2 - Optical film - Google Patents

Description

The present invention relates to an optical film formed by a wet process and having excellent transparency and antireflection performance.

Magnesium fluoride is a material having a wide transmission wavelength range and the lowest refractive index, and is therefore widely used as a material for antireflection films for optical applications.

When magnesium fluoride is used as an antireflection film, it is often used as one layer of a multilayer film mainly composed of several kinds of materials. In this case, as a principle of the antireflection film of the multilayer film, it is essential to control the refractive index of each layer in order to reduce the reflection due to the interference between the reflected lights between the layers of the multilayer film.

The formation of magnesium fluoride is generally carried out by a dry process by vacuum vapor deposition as disclosed in Patent Document 1. However, the dry process has problems that uniform coating is difficult for a large area and a small radius of curvature, and the production cost is high.

On the other hand, as a method for solving the problem in the dry process, film formation by a wet process has been reported, but the film obtained by the wet process tends to be porous and has a problem that the transparency of the film is inferior. ..

Further, Patent Document 2 is disclosed as a method for obtaining a dense film by a wet process, but since information on the synthesis of a raw material for magnesium fluoride is not described, a transparent film comparable to vacuum vapor deposition is produced. Couldn't.

Japanese Unexamined Patent Publication No. 11-223707 Japanese Unexamined Patent Publication No. 59-213643 Japanese Unexamined Patent Publication No. 2001-233611 Japanese Unexamined Patent Publication No. 2008-139581

Therefore, it is an object of the present invention to provide an optical film having excellent transparency and antireflection property at low cost.

As a result of diligent studies to solve the above problems, the present inventors have made trifluoro having a small particle size in the sol solution when forming magnesium fluoride by a wet process using a trifluoromagnesium acetate sol. We have found that the above problems can be solved by using magnesium acetate, and have completed the present invention.

That is, the present invention is a solution for forming an optical film containing a magnesium fluoride layer, which comprises nano-sized magnesium acetate fine particles, 3-methyl-2,4-pentandione, a solvent, and the like. It is a solution characterized by containing.

The present invention further average particle diameter of preparative trifluoroacetic acid magnesium particles, is preferably in the range of 5 to 50 nm.

In the present invention, it is preferable that the solvent has a Hansen parameter (δ _d , δ _p , δ _H ) represented by the following formula.

15.0 [MPa ^1/2 ] ≤δ _d ≤16.5 [MPa ^1/2 ] (I)
4.0 [MPa ^1/2 ] ≤ δ _p ≤ 8.0 [MPa ^1/2 ] (II)
9.0 [MPa ^1/2 ] ≤ δ _H ≤ 14.0 [MPa ^1/2 ] (III)

Further, the solvent is more preferably 2-ethyl-1-butanol, butyl carbitol, or 1-butoxy-2-propanol.

Furthermore, in the present invention, the content of the trifluoroacetic acid magnesium particles contained in dissolved solution a and [%], the relationship of 3 content of methyl-2,4-pentanedione b [%] is the following formula It is preferably represented.

8.0 ≤ a ≤ 27.0 (IV)
2.0 ≤ b ≤ 6.0 (V)
a / b ≧ 2 (VI)

According to the present invention, it is possible to provide an optical film having excellent transparency and antireflection performance, which can be applied to an optical panel or an optical lens, at low cost.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. The details of the optical film will be specifically described.

The optical film of the present invention is formed by a sol solution containing magnesium fluoride and a magnesium fluoride layer containing nano-sized magnesium trifluoroacetate fine particles, α-substituted β-diketone, and a solvent. Specifically, details of the magnesium trifluoroacetate, the α-substituted β-diketone, and the solvent will be described below.

1. 1. Magnesium Trifluoroacetate Magnesium trifluoroacetate is a precursor for forming magnesium fluoride in a wet process, and is obtained by, for example, the reaction of the following reaction formula (1).

<Average particle size of magnesium trifluoroacetate>
The average particle size of magnesium trifluoroacetate is preferably in the range of 5 nm to 50 nm, and more preferably in the range of 5 nm to 30 nm. When the average particle size is 5 nm or less, it is difficult to form a desired film thickness when forming a film. Further, when the average particle size exceeds 50 nm, the gap between the particles becomes large and a dense film is not formed.

Here, the "average particle size" indicates the median diameter (D ₅₀ ) measured by a dynamic light scattering type particle size distribution measuring device.

2. α-substituted β-diketone The α-substituted β-diketone acts as a stabilizer when preparing the trifluoromagnesium acetate sol and suppresses the aggregation of the trifluoromagnesium acetate sol particles. The α-substituted β-diketone is represented by the following general formula (1).

_{[R 1} , R ₂ , and R ₃ in the formula are alkyl groups having the same or different carbon atoms 1 to 3, respectively].

In the above formula (1), when _{the carbon chains of R 1} , R ₂ , and R ₃ become long, the α-substituted β-diketone remains in the film after the film formation, so that the optical characteristics deteriorate. Further, in the _{absence of the alkyl groups of R 1} , R ₂ , and R ₃ , the effect of stabilizing the dispersion of the trifluoromagnesium acetate sol particles in the solution becomes insufficient, so that the particle size of the sol particles becomes large. Among the α-substituted β-diketones, 3-methyl-2,4-pentandione is particularly preferable.

3. 3. Solvent The solvent is preferably an organic solvent. Organic solvents include alcohol-based solvents, aliphatic or alicyclic hydrocarbon-based solvents, various aromatic hydrocarbon-based solvents, various ester-based solvents, various ketone-based solvents, various ether-based solvents, and aprotic polarities. Examples include solvents. When preparing the trifluoromagnesium acetate sol used for the optical membrane of the present invention, it is preferable to use a solvent having _{a specific Hansen parameter (δ d} , δ _p , δ _H). The dispersion term δ _d is preferably 15.0 or more and 16.5 or less, the polar term δ _p is preferably 4.0 or more and 8.0 or less, and the hydrogen bond term δ _H is preferably 9.0 or more and 14.0 or less.

When the dispersion term is less than 15.0, magnesium trifluoroacetate precipitates without maintaining the dispersed state, and when it is larger than 16.5, the particle size becomes large and it is difficult to form a dense film. When the polar term δ _p is less than 4.0 or larger than 8.0, the particle size becomes large and it is difficult to form a dense film. Similarly, when the hydrogen bond term δ _H is less than 9.0 or larger than 14.0, the particle size becomes large and it is difficult to form a dense film.

Preferred solvents include, for example, 2-ethylbutanol, 1-butoxy-2-propanol, butyl carbitol and the like. These organic solvents may be used alone or in combination of two or more. Further, a solvent having the above Hansen parameters (δ _d , δ _p , δ _H ) may be appropriately prepared by combining two or more kinds of solvents.

4. Sol solution The sol solution contains trifluoromagnesium acetate fine particles, α-substituted β-diketone, and a solvent. Hereinafter, the content, ratio, etc. of each component will be described.

(1) Content of magnesium trifluoroacetate The content a [%] of magnesium trifluoroacetate in the sol solution is preferably 5.0 to 35.0%, more preferably 8.0% or more and 27.0% or less. preferable. If the content a [%] is less than 5.0%, the proportion of magnesium trifluoroacetate is too small and the film forming property is deteriorated. When the content a [%] exceeds 35.0%, the amount of magnesium trifluoroacetate in the solution becomes excessive, so that the particles aggregate with each other and the stability of the dispersed state in the solution decreases. do.

(2) Content of α-substituted β-diketone The content b [%] of α-substituted β-diketone in the sol solution is preferably 0.7 to 15.0%, more preferably 2.0% or more and 6.0% or less. preferable. When the content b [%] is less than 0.7%, the ratio of the α-substituted β-diketone to magnesium trifluoroacetate is too small, so that the particles aggregate with each other and the dispersion state in the solution is stable. Decreases. When the content b [%] exceeds 15.0%, the content of the α-substituted β-diketone becomes excessive, so that the optical properties deteriorate due to the residue in the film after the film formation.

(3) Ratio of magnesium trifluoroacetate and α-substituted β-diketone The ratio of a [%] and b [%], a / b, is preferably 0.7 or more, more preferably 2.0 or more. When a / b is less than 0.7, the ratio of the α-substituted β-diketone to magnesium trifluoroacetate is too small, so that the sol particles aggregate with each other and the stability of the dispersed state in the solution decreases. Further, for the stability of the dispersed state, a / b is preferably 30.0 or less, more preferably 10.0 or less.

5. Layer structure of optical film The optical film may be composed of a single layer of magnesium fluoride layer, or may be composed of two or more layers including a layer made of other materials. In the case of an optical film composed of two or more layers, it is preferable to include a layer having pores in order to further improve the antireflection performance. Further, the layer having the pores is preferably formed on the upper part of the magnesium fluoride layer. Then, the layer having pores is used so as to be closer to the surface layer than the magnesium fluoride layer.

As the refractive index adjusting layer, a layer of _{an inorganic oxide such as ZrO 2 or} Al ₂ O ₃ may be further formed. From the viewpoint of transmittance, the inorganic oxide or the like used preferably has an average particle size of 150 nm or less, more preferably 50 nm or less.

The layer having pores can have its refractive index lowered by the air contained in the pores (refractive index 1.0). As a means for forming the vacancies, there is a method of forming the vacancies by hollow particles composed of particles having vacancies inside and having a shell around the outside of the vacancies. Further, a method of forming pores in the gaps between solid spherical particles or irregularly shaped particles such as chains, a method of forming pores by volatilization of a solvent or the like when forming a layer, and the like can be mentioned. Among these, as a method for obtaining a higher porosity and a lower refractive index, a method of forming pores with hollow particles is preferable.

As the material constituting the hollow particles, a material having a low refractive index is preferable. Examples of the material include _{inorganic materials such as SiO 2} , magnesium fluoride, and organic resins such as fluorine and silicone. _{Among these, SiO 2} is more preferable because it is easy to produce particles. As a _{method for producing the hollow particles of SiO 2} , for example, the hollow particles can be produced by the methods described in Patent Document 3, Patent Document 4, and the like. The hollow particles make it possible to reduce the refractive index of a layer formed by stacking a plurality of particles aligned in a direction parallel to the surface of a base material.

The average particle size of the hollow particles is preferably 15 nm or more and 100 nm or less, preferably 15 nm or more and 60 nm or less. When the average particle size of the hollow particles is less than 15 nm, it is difficult to stably produce core particles. Further, when the average particle size of the hollow particles exceeds 100 nm, the voids between the particles become large, so that large voids are likely to be generated, and scattering is generated according to the size of the particles.

Here, the "average particle size" of the hollow particles is the average ferret diameter. This average ferret diameter can be measured by image processing as observed by a transmission electron microscope image. As the image processing method, a commercially available image processing such as image Pro PLUS (manufactured by Media Cybernetics) can be used. In a predetermined image region, if necessary, the contrast is adjusted as appropriate, the average ferret diameter of each particle is measured by particle measurement, and the average value can be calculated and obtained.

The thickness of the shell of the hollow particles is 10% or more and 50% or less, preferably 2 of the average particle size.
0% or more and 35% or less is desirable. If the thickness of the shell is less than 10%, the strength of the particles will be insufficient. Further, when the thickness of the shell exceeds 50%, the hollow effect does not appear remarkably in the refractive index.

Examples of the material constituting the solid spherical particles or irregularly shaped particles such as chains include _{inorganic materials such as SiO 2} and magnesium fluoride, and organic resins such as fluorine and silicone, as in the case of the hollow particles. _{Among these, SiO 2} is more preferable because it is easy to produce particles.

The particle size of the solid spherical particles or chain-like particles is preferably 10 nm or more and 100 nm or less, preferably 10 nm or more and 60 nm or less. When the average particle size is less than 10 nm, it is difficult to stably create pores in the gaps between the particles. On the other hand, when it exceeds 100 nm, the voids between the particles become large, so that large voids are likely to be generated, and scattering is generated according to the size of the particles.

The layer having pores may be formed only of hollow particles or spherical or irregularly shaped particles, but a method of fixing the particles with a binder is preferable. The binder is not particularly limited as long as it can fix the particles.

6. Method for forming an optical film The optical film of the present invention can be produced by applying the above sol solution to a base material and heating the applied base material. The sol solution prepared above is formed by applying it on an optical element. As a method for forming the coating film, 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 adopted. The film thickness can be controlled by changing the pulling speed in the dipping method, the substrate rotation speed in the spin coating method, and the like, and changing the concentration of the coating solution.

Examples of the base material in the present invention include glass.

If there is an intermediate layer between the optical film and the surface of the substrate, the inorganic oxide or compound is heated to melt, evaporate or sublimate, and the evaporated or sublimated particles adhere to and deposit on the surface of the substrate. The intermediate layer can be formed by using a dry process such as vacuum deposition. Further, after applying a film-forming liquid containing an inorganic oxide, an inorganic compound, or a solvent on the surface of the base material by a wet process such as a dipping method, a spin coating method, a spray method, a printing method, or a flow coating method. , A method having a drying step may be used. The optical film is formed by applying the trifluoromagnesium acetate solution on the surface of the substrate or the intermediate layer by a wet process such as a dipping method, a spin coating method, a spray method, a printing method, or a flow coating method. A method having a step of heating or drying after the work is preferable. The film forming method is not limited to these methods.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded. In addition, what is described as "part" and "%" regarding the amount of a component is based on mass unless otherwise specified. The average particle size was measured using a nanoparticle particle size distribution measuring device (trade name "UPA-EX250", manufactured by Nikkiso Co., Ltd.).

[Example 1]
(1) Preparation of materials <Synthesis of α-substituted β-diketone>
3-Methyl-2,4-pentandione was synthesized as an α-substituted β-diketone.

To a reaction vessel equipped with a thermometer, a reflux tube, a dropping funnel and a stirrer, 100 parts of potassium carbonate (base catalyst) and 200 parts of acetone (solvent) were added and stirred. Subsequently, 100 parts (substrate) of acetylacetone was added with stirring, and then 200 parts (reactant) of iodine methane was added dropwise, and the mixture was reacted in a water bath at 55-60 ° C. for 6 hours. Then, suction filtration is performed to remove insoluble components, and the obtained filtrate is concentrated using a rotary evaporator, and the obtained concentrate is distilled under reduced pressure to obtain 3-methyl-2,4-pentandione. Obtained.

<Preparation of trifluoromagnesium acetate sol solution>

In a reaction vessel equipped with a thermometer, a dropping funnel and a stirrer, 5 parts of magnesium diethoxydo (substrate), 119 parts of 2-ethyl1-butanol (solvent), 3-methyl-2,4-pentandione 9 A portion (stabilizer) was added and stirring was performed at 100 rpm. Subsequently, 11 parts of trifluoroacetic acid (reactant) was added dropwise over 85 minutes with stirring, and then the reaction was carried out while keeping the temperature at 25 ° C. in a water bath to obtain a trifluoromagnesium acetate sol solution.

(2) Manufacture of optical film The substrate (slide glass water edge polishing material: soda glass square 3t x 40 x 40mm) is ultrasonically cleaned and dried with isopropyl alcohol for 30 minutes, then ozone cleaning and substrate cleaning spray for 30 minutes. The dust was removed with a glass substrate for coating. On this coating glass substrate, 0.3 ml of the above trifluoromagnesium acetate sol solution is spun using a spin coating device (trade name: "1HD7", manufactured by Mikasa Co., Ltd.) at a rotation speed of 4000 pm in 90 seconds. I coated it. Then, it was calcined at 250 degreeC for 2 hours to produce an optical film (layer structure A in Table 1).

[Example 2]
Examples except that the amount charged was changed to 17 parts of magnesium diethoxydo, 82 parts of 2-ethyl1-butanol, 9 parts of 3-methyl-2,4-pentandione, and 36 parts of trifluoroacetic acid (reactant). A trifluoromagnesium acetate sol solution was prepared in the same manner as in 1. Then, a film was formed by the same method as in Example 1 to produce an optical film.

[Example 3]
Examples except that the amount charged was changed to 4 parts of magnesium diethoxydo, 123 parts of 2-ethyl1-butanol, 9 parts of 3-methyl-2,4-pentandione, and 8 parts of trifluoroacetic acid (reactant). A trifluoromagnesium acetate sol solution was prepared in the same manner as in 1. Then, a film was formed by the same method as in Example 1 to produce an optical film.

[Example 4]
Examples except that the amount charged was changed to 20 parts of magnesium diethoxydo, 74 parts of 2-ethyl1-butanol, 9 parts of 3-methyl-2,4-pentandione, and 41 parts of trifluoroacetic acid (reactant). A trifluoromagnesium acetate sol solution was prepared in the same manner as in 1. Then, a film was formed by the same method as in Example 1 to produce an optical film.

[Example 5]
(1) Preparation of material <Preparation of hollow particle liquid>
Hollow silica slurry IPA dispersion (Thruria 1110 manufactured by JGC Catalysts and Chemicals Co., Ltd., average ferre diameter 55 nm, solid content concentration 20.5 wt%,) 4.5 parts by weight and 9.00 parts by weight of 1-ethoxy-2-propanol 100 ml. It was placed in a eggplant flask, concentrated by an evaporator, and the solvent was replaced with 1-ethoxy-2-propanol. Then, 11.0 parts by weight of 1-ethoxy-2-propanol and 15.0 parts by weight of 1-butoxy-2-propanol were added to add 13.5 parts by weight of 2-ethylbutanol to obtain a 1.9 wt% hollow particle solution. Prepared.

<Preparation of binder solution>
75 parts by mass of xylene was added to 1 part by mass of a silicone resin (KR-311 manufactured by Shin-Etsu Chemical Co., Ltd.) to prepare a 0.8 wt% binder solution.

The trifluoromagnesium acetate sol solution was prepared in the same manner as in Example 2.

(2) Production of Optical Film On the magnesium fluoride layer formed by the same method as in Example 1, 0.3 ml of the above hollow particle solution is spin-coated at a rotation speed of 2000 rpm for 90 seconds using a spin coater. bottom. 0.3 ml of the binder solution was spin-coated on the binder solution at a rotation speed of 2000 rpm for 90 seconds and heat-treated at 200 ° C. for 2 hours to obtain an optical film (layer structure B in Table 1). ..

[Example 6]
(1) Preparation of materials <Preparation of silica particle dispersion solution>
To a reaction vessel equipped with a thermometer and a stirrer, 95 parts of ethyl silicate (substrate) and 85 parts of a 0.1% hydrochloric acid aqueous solution were added, and the mixture was stirred at 200 rpm while keeping the water bath at 20 ° C. and reacted for 60 minutes. The obtained solution was transferred to a heat-resistant container, and a condensation reaction was carried out in an oven at 200 ° C. for 2 hours to obtain bulk silica. The obtained silica was pulverized in a pot with a steel ball using a ball mill (V-1ML manufactured by Irie Trading Co., Ltd.), and 20 parts of the pulverized silica powder was dispersed in 180 parts of 2-propanol. The obtained silica dispersion solution was further atomized by a wet pulverizer (HJP-25001 manufactured by Sugino Machine Limited) to obtain a silica particle dispersion solution having a solid content of 10 wt% (average particle diameter 13 nm).

The trifluoromagnesium acetate sol solution was prepared in the same manner as in Example 2. The binder liquid was prepared by the same method as in Example 5.

(2) Production of Optical Film On the magnesium fluoride layer formed by the same method as in Example 1, 0.3 ml of the silica particle solution was spin-coated at a rotation speed of 2000 rpm for 90 seconds using a spin coater. bottom. A binder solution of 0.3 ml was spin-coated on the binder solution at a rotation speed of 2000 rpm for 90 seconds and heat-treated at 200 ° C. for 2 hours to obtain an optical film (in Table 1, layer structure C). ).

[Example 7]
(1) Preparation of materials <Preparation of ZrO ₂ dispersion solution>
In a reaction vessel equipped with a thermometer, a dropping funnel and a stirrer, 30 parts of zirconium tetra-n-butoxide (substrate), 70 parts of 2-ethyl-1-butanol (solvent), 3-methyl-2,4- Five parts of pentangion (stabilizer) was added, and the mixture was stirred at 60 rpm. Separately, in a reaction vessel equipped with a thermometer and a stirrer, 2 parts of 0.01N hydrochloric acid (acid catalyst), 130 parts of 2-ethyl-1-butanol (solvent), 1-ethoxy-2- An acid catalyst solution was prepared by adding 90 parts of propanol (solvent) and shaking. The prepared acid catalyst solution was added to the above zirconium tetra-n-butoxide solution and stirred at 120 rpm to obtain a _{ZrO 2 dispersion solution.}

The trifluoromagnesium acetate sol solution was prepared in the same manner as in Example 2.

(2) Manufacture of optical film Substrate (slide glass water edge polishing material: soda glass square 3t x 40 x 40mm) is ultrasonically cleaned with isopropyl alcohol for 30 minutes, dried, and then ozone cleaned for 30 minutes to clean the substrate. Dust was removed with a spray to make a glass substrate for coating. On this coating glass substrate, _{0.3 ml of the above ZrO 2} dispersion solution was spin-coated at a rotation speed of 2000 rpm for 60 seconds using a spin coating device (trade name: "1HD7", manufactured by Mikasa Co., Ltd.). , 200 ° C. for 2 hours. 0.3 ml of the above trifluoromagnesium acetate sol solution was spin-coated on the film at a rotation speed of 2000 rpm for 90 seconds and fired at 250 ° C. for 2 hours. By repeating the above steps, _{a 12-layer optical film in which the ZrO 2} layer and the magnesium fluoride layer were repeated was further formed on the film (layer structure D in Table 1).

[Example 8]
(1) Preparation of Material The trifluoromagnesium acetate sol solution was prepared by the same method as in Example 2. As the ZrO ₂ dispersion solution, a dispersion solution was prepared in the same manner as in Example 6.

(2) Production of Optical Film To the uppermost layer in which 12 optical films were formed in the same manner as in Example 6, 0.3 ml of a hollow particle solution prepared in the same manner as in Example 5 was rotated using a spin coating device. An optical film was formed by spin coating at several 2000 rpm for 60 seconds and firing at 200 ° C. for 2 hours (Table 1, layer structure E).

The layer structure of each example (layers A to E shown in Table 1 below) is shown in Table 3.

[Example 9]
A trifluoromagnesium acetate sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 88 parts of 2-ethyl1-butanol and the stabilizer was changed to 3 parts of 3-methyl-2,4-pentanedione. Then, an optical film was formed by the same method as in Example 1.

[Example 10]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 85 parts of 2-ethyl1-butanol and the stabilizer was changed to 6 parts of 3-methyl-2,4-pentanedione. Then, an optical film was formed by the same method as in Example 1.

[Example 11]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 90 parts of 2-ethyl1-butanol and the stabilizer was changed to 1 part of 3-methyl-2,4-pentanedione. Then, an optical film was formed by the same method as in Example 1.

[Example 12]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 77 parts of 2-ethyl1-butanol and the stabilizer was changed to 14 parts of 3-methyl-2,4-pentanedione. Then, an optical film was formed by the same method as in Example 1.

[Example 13]
A sol solution was prepared in the same manner as in Example 2 except that the stabilizer 3-methyl-2,4-pentanedione was changed to 5-methylhexane-2,4-dione. Then, an optical film was formed by the same method as in Example 1.

[Example 14]
A sol solution was prepared in the same manner as in Example 2 described above except that the solvent was changed to 82 parts of butyl carbitol. Then, an optical film was formed by the same method as in Example 1.

[Example 15]
A sol was prepared in the same manner as in Example 2 above, except that the solvent was changed to 82 parts of 1-butoxy-2-propanol. Then, an optical film was formed by the same method as in Example 1.

[Example 16]
A sol was prepared in the same manner as in Example 2 described above except that the solvent was changed to 82 parts of methyl carbitol. Then, an optical film was formed by the same method as in Example 1.

[Example 17]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 25 parts of n-pentanol and 58 parts of acetic acid. Then, an optical film was formed by the same method as in Example 1.

[Example 18]
A sol solution was prepared in the same manner as in Example 2 described above, except that the solvent was changed to a mixed solvent consisting of 41 parts of n-pentanol and 41 parts of cyclohexanone. Then, an optical film was formed by the same method as in Example 1.

[Example 19]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 4 parts of n-pentanol and 78 parts of acetic acid. Then, an optical film was formed by the same method as in Example 1.

[Example 20]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of methyl carbitol. Then, an optical film was formed by the same method as in Example 1.

[Example 21]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of n-hexanol. Then, an optical film was formed by the same method as in Example 1.

[Example 22]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 33 parts of N, N-dimethylformamide and 49 parts of 1-butoxy-2-propanol. Then, an optical film was formed by the same method as in Example 1.

[Example 23]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of methylisobutylcarbitol. Then, an optical film was formed by the same method as in Example 1.

[Example 24]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of n-pentanol. Then, an optical film was formed by the same method as in Example 1.

[Example 25]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 41 parts of n-pentanol and 41 parts of methyl isobutyl ketone. Then, an optical film was formed by the same method as in Example 1.

[Example 26]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of 1-methoxy-2-propanol. Then, an optical film was formed by the same method as in Example 1.

[Example 27]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of methyl isobutyl ketone. Then, an optical film was formed by the same method as in Example 1.

[Example 28]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of ethylene glycol. Then, an optical film was formed by the same method as in Example 1.

[Example 29]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of hexane. Then, an optical film was formed by the same method as in Example 1.

[Example 30]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 49 parts of ethylene glycol and 33 parts of toluene. Then, an optical film was formed by the same method as in Example 1.

[Example 31]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 12 parts of ethylene glycol and 70 parts of isooctyl alcohol. Then, an optical film was formed by the same method as in Example 1.

[Example 32]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 49 parts of isooctyl alcohol and 33 parts of diethyl ether. Then, an optical film was formed by the same method as in Example 1.

[Example 33]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of etanol. Then, an optical film was formed by the same method as in Example 1.

[Example 34]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of butyl acetate. Then, an optical film was formed by the same method as in Example 1.

[Example 35]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of N, N-dimethylformamide. Then, an optical film was formed by the same method as in Example 1.

[Example 36]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 41 parts of toluene and 41 parts of 2-propanol. Then, an optical film was formed by the same method as in Example 1.

[Example 37]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of cyclooctanone. Then, an optical film was formed by the same method as in Example 1.

[Example 38]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of cyclohexanone. Then, an optical film was formed by the same method as in Example 1.

[Example 39]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 54 parts of isooctyl alcohol and 29 parts of hexane. Then, an optical film was formed by the same method as in Example 1.

[Example 40]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of methyl ethyl ketone. Then, an optical film was formed by the same method as in Example 1.

[Example 41]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 54 parts of butyl cellosolve and 29 parts of xylene. Then, an optical film was formed by the same method as in Example 1.

[Example 42]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 49 parts of isooctyl alcohol and 33 parts of acetone. Then, an optical film was formed by the same method as in Example 1.

[Example 43]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to a mixed solvent consisting of 66 parts of isooctyl alcohol and 16 parts of methanol. Then, an optical film was formed by the same method as in Example 1.

[Example 44]
A sol solution was prepared in the same manner as in Example 2 except that the solvent was changed to 82 parts of toluene. Then, an optical film was formed by the same method as in Example 1.

[Comparative Example 1]
A sol solution was prepared in the same manner as in Example 2 except that the stabilizers 3-methyl-2 and 4-pentandione were not added. Then, an optical film was formed by the same method as in Example 1.

[Comparative Example 2]
A sol solution was prepared in the same manner as in Example 2 except that the stabilizer 3-methyl-2,4-pentandione was changed to acetic anhydride. Then, an optical film was formed by the same method as in Example 1 described above.

[Reference example 1]
<Manufacturing of optical film>
The substrate (slide glass water edge polishing material: soda glass square 3t x 40 x 40mm) is ultrasonically cleaned with isopropyl alcohol for 30 minutes, dried, and then ozone-cleaned for 30 minutes to remove dust with a substrate cleaning spray. It was used as a glass substrate for coating. A magnesium fluoride layer was formed on this coating glass substrate by a vacuum vapor deposition method.

Table 2 shows the composition of the trifluoromagnesium acetate solution and the average particle size of the trifluoromagnesium acetate particles in the solution.

<Evaluation of optical film>
The optical film was evaluated with respect to the following four points.
(1) Refractive index of magnesium fluoride layer (evaluation 1)
The refractive index of the magnesium fluoride layer in the optical film was measured at a wavelength of 550 nm using an automatic multi-incident angle spectroscopic ellipsometer V-VASE (manufactured by JA Woolam). The results are shown in Table 3.

(2) Reflectance (evaluation 2)
Using a reflection spectroscopic film thickness meter (FE3000 manufactured by Otsuka Electronics Co., Ltd.), the reflectance behavior of the optical film in the wavelength range of 350 nm to 550 nm was measured at an incident angle of 0 degrees, and the optical film was measured according to the evaluation criteria shown below. The reflectance was evaluated. The results are shown in Table 3. The layer structure of each optical film is as shown in Table 3.

⊚: The maximum reflectance in the wavelength range of 350 nm to 550 nm is less than 1%, and the difference in reflectance (maximum reflectance-minimum reflectance) in the wavelength range of 350 nm to 550 nm is 0.5% or less. be.
◯: The maximum reflectance in the wavelength range of 350 nm to 550 nm is less than 1%, and the difference in reflectance in the wavelength range of 350 nm to 550 nm (maximum reflectance-minimum reflectance) exceeds 0.5%. It is less than 1%.
Δ: The maximum reflectance in the wavelength range of 350 nm to 550 nm is 1% or more and less than 2%.
Δ ×: The maximum reflectance in the wavelength range of 350 nm to 550 nm is 2% or more and less than 4%.
X: The maximum reflectance in the wavelength range of 350 nm to 550 nm is 4% or more.

(3) Transmittance (evaluation 3)
Using a spectrophotometer UV-Vis (U-3310 manufactured by Hitachi High-Tech Science Co., Ltd.), the transmittance behavior of the optical film in the wavelength range of 350 nm to 550 nm was measured at an incident angle of 0 degrees, and the evaluation criteria shown below were used. Therefore, the transmittance of the optical film was evaluated. The results are shown in Table 3. The layer structure of each optical film is as shown in Table 1.

⊚: The minimum transmittance in the wavelength range of 350 nm to 550 nm is 98% or more.
◯: The minimum transmittance in the wavelength range of 350 nm to 550 nm is 96% or more and less than 98%.
Δ: The minimum transmittance in the wavelength range of 350 nm to 550 nm is 94% or more and less than 96%.
X: The minimum transmittance in the wavelength range of 350 nm to 550 nm is less than 94%.

(4) Film formation property (evaluation 4)
The appearance of the magnesium fluoride layer after film formation was visually observed and observed with a laser microscope VK-9510 (manufactured by KEYENCE CORPORATION), and the film forming property of the magnesium fluoride layer was evaluated according to the following evaluation criteria. The results are shown in Table 3.

◯: Uniform film formation is formed Δ: There is a partial difference in film thickness ×: There is a part that has not been coated.

As is clear from the evaluation results shown in Table 3, the optical films of Examples 1 to 44 are dense films and have good film forming properties, and can obtain optical films having excellent transparency and antireflection performance. rice field.

The optical film of the present invention is excellent in transparency and antireflection, and can be applied to an optical panel such as a display device and an optical lens such as a surveillance camera.

Claims (5)

A solution for forming an optical film containing a magnesium fluoride layer, and comprising a magnesium trifluoroacetate fine nano-sized, and 3-methyl-2,4-pentanedione, and a solvent soluble liquid. The solution according to claim 1, wherein the average particle size of the trifluoromagnesium acetate fine particles is in the range of 5 to 50 nm. The solution according to claim 1 or 2 , wherein the solvent has a Hansen parameter (δd, δp, δH) represented by the following formula.
15.0 [MPa ^1/2 ] ≤δ _d ≤16.5 [MPa ^1/2 ] (I)
4.0 [MPa ^1/2 ] ≤ δ _p ≤ 8.0 [MPa ^1/2 ] (II)
9.0 [MPa ^1/2 ] ≤ δ _H ≤ 14.0 [MPa ^1/2 ] (III) The solution according to any one of claims 1 to 3 , wherein the solvent is 2-ethyl-1-butanol, butyl carbitol, or 1-butoxy-2-propanol. Claims and content a [%] of the magnesium trifluoroacetate fine particles contained in the solvent liquid, the relationship of 3 content of methyl-2,4-pentanedione b [%] is represented by the following formula The solution according to any one of 1 to 4 .
8.0 ≤ a ≤ 27.0 (IV)
2.0 ≤ b ≤ 6.0 (V)
a / b ≧ 2 (VI)