JP2628589B2 - Anti-reflection coating for polyurethane lens - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film for preventing surface reflection of an optical element, and more particularly to a low refractive index film and a high refractive index film useful for a polyurethane lens. The present invention relates to a multilayer antireflection film which is alternately stacked.

[Prior art] Optical elements such as optical lenses, filters, polarizers, and semi-transparent mirrors have been mainly made of inorganic glass, but in recent years plastics have been used because of their light weight and excellent impact resistance. Is increasingly used.
As the plastic lens, polyethylene glycol bisallyl carbonate (CR-39) or polymethyl methacrylate (PMMA) is generally used. However, the refractive index of this plastic material is 1.50 or less.For example, when used as a lens material, if the power becomes strong, the thickness of the lens must be increased, and not only the advantage of plastic such as light weight is lost, but also the eyeglasses In the case of a lens for use, aesthetics are deteriorated, which is not preferable. In particular, in the case of a concave lens, the thickness around the lens is increased, and birefringence and chromatic aberration occur, which is not preferable. for that reason,
A high-refractive-index, low-dispersion plastic material capable of reducing the thickness of a lens and having little chromatic aberration while utilizing the characteristics of plastic having a low specific gravity is desired. As a material therefor, a lens made of polyurethane obtained by reacting a polyol or polythiol with a polyisocyanate is known.

In such an optical element, surface reflection lowers the transmittance of the optical system and causes an increase in light that does not contribute to image formation, thereby causing a reduction in image contrast. For this reason, both the optical element made of inorganic glass and the optical element made of plastic are provided with an antireflection film on the surface of many optical elements to reduce surface reflection.

The anti-reflection film is generally formed as a vapor-deposited film using a metal or metal oxide as a raw material, and the vapor-deposited film is a multilayer in which a single-layer anti-reflection film and a low-refractive-index film and a high-refractive-index film are alternately laminated. They are roughly classified into antireflection films. In addition, both the single-layer antireflection film and the multilayer antireflection film have desired refractive index, optical homogeneity, excellent transparency and other optical characteristics, as well as scratch resistance. Mechanical properties such as excellent heat resistance and excellent adhesion, and chemical properties such as excellent acid resistance and excellent heat resistance are required.

As a high-refractive-index film of a multilayer antireflection film provided on an optical element made of inorganic glass, a vapor-deposited film made of zirconium oxide (ZrO ₂ ) has been widely used as a material satisfying the above-mentioned properties. The high-refractive-index film of the multilayer antireflection film provided in the optical element is also excellent in transparency, high refractive index, and the like.
As disclosed in Japanese Patent Application No. 56-116003, an evaporated film using ZrO ₂ as a raw material is used.

[Problems to be Solved by the Invention] However, compared to inorganic lenses, plastic lenses generally have poor heat resistance, and among plastic lenses, polyurethane lenses have particularly poor heat resistance. Therefore, a ZrO ₂ deposited film is formed on a polyurethane lens substrate. In this case, the substrate temperature during film formation cannot be sufficiently increased. as a result,
ZrO ₂ deposited film formed by the temporary temperature polyurethane lens substrate, compared with ZrO ₂ deposited film formed at high temperatures, optical properties, poor mechanical properties and chemical properties, and these properties There was a drawback that durability was poor.

On the other hand, in recent years, as an improvement from the lens design in order to improve the optical performance of the plastic lens and to reduce the lens thickness, an aspherical lens design in which the curve of the refractive surface of the lens is made shallow has been used. . However, in the lens design, making the curve of the refraction surface shallow, for example, in the case of a spectacle lens, has a problem of backside reflection, that is, a problem of being easily reflected by incident light from the concave side (eye side). Therefore, a low-reflection anti-reflection film was required,
The refractive index of the above-mentioned vapor deposited film made of ZrO ₂ is around 1.90, which has a limit on the refractive index, which also affects the film design of the high refractive index layer of the multi-reflection film requiring a high refractive index. For example, a high-performance antireflection film that can suppress the reflectance to 1% or less could not be obtained.

Accordingly, a first object of the present invention is to solve the above-mentioned problems and to provide excellent optical, mechanical and chemical properties even when vapor-deposited on a polyurethane lens substrate at a low temperature, and to achieve these properties. It is another object of the present invention to provide a multilayer antireflection film having improved durability, and a second object is to provide a multilayer antireflection film having low reflection.

Means for Solving the Problems The present invention has been made in order to solve the above-mentioned object, and a multilayer antireflection film for a polyurethane lens in which a low refractive index film and a high refractive index film are alternately laminated. Counting from the substrate side, the first layer has an optical thickness of 0.09λ to 0.14λ and a metal oxide film containing tantalum, zirconium and yttrium, and an optical thickness of 0.04λ to 0.07λ; ,
A second layer composed of a metal oxide film having an optical film thickness of 0.24λ to 0.28λ and containing tantalum, zirconium and yttrium. A third refractive index film
An object of the present invention is to provide a multilayer antireflection film for a polyurethane lens, wherein the layer has an optical thickness of 0.24λ to 0.26λ and is formed of a low refractive index film made of a silicon oxide film.

The multilayer antireflection film of the present invention is preferably used for a high refractive index polyurethane lens having nd = 1.54 or more.
It is preferably used for polyurethane having a high refractive index of 57 to 1.61.

When the multilayer antireflection film of the present invention is provided on a polyurethane optical element, a hard coat layer containing an organosilicon polymer is formed on the optical element surface by a coating method such as a dipping method or a spin coating method. It is preferable to provide the multilayer antireflection film of the present invention on the film.

The hard coat film containing an organosilicon polymer formed on the polyurethane lens substrate includes a layer made of a compound selected from the group consisting of a compound having the following general formula and / or a hydrolyzate thereof. It can be obtained by forming and curing on a polyurethane lens substrate by a method, a coating method or the like.

Formula (R ₁ ) _a (R ₂ ) _b Si (OR ₃ ) _{4- (a + b)} (where R ₁ and R ₂ are an alkyl group having 1 to 10 carbon atoms, an aryl group, an alkyl halide, , An organic group having an aryl, alkenyl, or epoxy group, a (meth) acryloxy group, a mercapto group, or a cyano group
Bonded to a silicon group by a Si-C bond,
₃ is an alkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group or an acyl group, and a and b are 0, 1 or 2
And a + b is 1 or 2. Examples of these compounds include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,
Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, λ-chloropropyltrimethoxysilane, λ-chloro Propyltriethoxysilane, λ-chloropropyltripropoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, λ-glycidoxypropyltrimethoxysilane, λ-glycidoxypropyltriethoxysilane, λ- (β -Glycidoxyethoxy) propyltrimethoxysilane, β- (3,4-epoxycyclohexyl)
Ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltri Methoxysilane, γ-mercaptopropyltriethoxysilane, N-
trialkoxy or triacyloxysilanes such as β (aminoethyl) -γ-aminopropyltrimethoxysilane, β-cyanoethyltriethoxysilane, and dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldisilane Ethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylphenyldimethoxysilane, γ-glycidoxypropylphenyldiethoxysilane, γ-chloro Propylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane Dialkoxysilanes such as γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane and methylvinyldiethoxysilane Or diacyloxysilanes.

These organosilicon compounds can be used alone or in combination of two or more.

Furthermore, various tetraalkoxysilanes or hydrolysates thereof can be used in combination with the above-mentioned organosilicon compound, although they are not used alone.

Examples of such tetraalkoxysilanes include:
Examples include methyl silicate, ethyl silicate, n-propyl silicate, isopropyl silicate, n-butyl silicate, sec-butyl silicate and t-butyl silicate.

Further, these organosilicon compounds can be cured without a catalyst, but various catalysts can be used to further promote the curing.

Such catalysts include Lewis acids, various acids or bases including Lewis acid salts, or organic carboxylic acids, chromic acid, hypochlorous acid, boron, bromic acid, selenous acid, thiosulfuric acid, orthosilicic acid, thiocyanic acid And metal salts such as nitrous acid, aluminate and carbonic acid, particularly alkali metal salts or ammonium salts, and alkoxides of aluminum, zirconium or titanium, or complex compounds thereof.

Furthermore, it is also possible to use the above-mentioned organosilicon polymer and another organic substance in combination.Examples of the other organic substance to be used in combination include an epoxy resin, an acrylic copolymer, and a hydroxyl group-containing polymer such as polyvinyl alcohol. .

Further, as other excipients, there are S as disclosed in Optica Actor (issued in July, 1962, p. 251).
Colloid sols of inorganic oxides such as i, Al, Ti, Sb, etc. can be used.

Furthermore, in order to facilitate the coating operation, it is also possible to use solvents that maintain a good storage state and various additives.

In addition, in order to improve the adhesion between the optical element and the multilayer anti-reflection film and the abrasion resistance, etc., a hard coat film formed between the optical element and the multilayer anti-reflection film or on the surface of the optical element and the multilayer reflection film are used. It is preferable that an underlayer is interposed between the anti-reflection film and the underlayer, and as such an underlayer, for example, a deposited film of silicon oxide or the like can be used, and in this case, the optical film thickness is 0.4λ to 0.6. λ is preferably used.

In forming the multilayer antireflection film of the present invention, a sputtering method using a similar sintered body as a target material, an ion plating method, or the like can be used in addition to the vacuum evaporation method.

In the present invention, a deposited film of a metal oxide containing tantalum, zirconium and yttrium is obtained by mixing zirconium oxide (ZrO ₂ ) powder, tantalum oxide (Ta ₂ O ₅ ) powder and yttrium oxide (Y ₂ O ₃ ) powder, Pellets formed by pressing and sintering are preferably deposited by electron beam heating. The composition ratio of the mixed raw material obtained by mixing the respective powders is preferably such that the molar ratio of ZrO ₂ is 1.0, Ta ₂ O ₅ is 0.8 to 1.8, and Y ₂ O ₃ is 0.05 to 0.3.

Thus deposited film obtained (hereinafter referred to as 3-component vapor-deposited film), as well as the the Ta ₂ O ₅ film is chemically extremely stable compared to the ZrO ₂ film, and a transparent comparable to the ZrO ₂ film It has nature. Further, the refractive index shows a high value of, for example, 2.00 to 2.10, which is effective from the viewpoint of film design.

When Ta ₂ O ₅ is less than 0.8 mol or more than 1.8 mol with respect to 1 mol of ZrO ₂ , absorption tends to occur in the obtained three-component vapor-deposited film, and 0.3 mol of Y ₂ O ₃ is used. If it exceeds, the vapor deposition rate increases, and the resulting three-component vapor-deposited film is easily absorbed, and the vapor deposition raw material is easily scattered, which is difficult to control.

EXAMPLES Examples of the present invention will be described below.

(Production of high refractive index polyurethane lens) 100 parts by weight of m-xylylene diisocyanate, 142 parts by weight of pentaerythritol tetrakis-3-mercaptopropionate, 6 parts by weight of di-n-butyl phosphate, and 0.25 parts by weight of dibutyltin dilaurate And 0.5 parts by weight of 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole as an ultraviolet absorber, and after sufficiently stirring, degassed under a vacuum of 1 mmHg for 60 minutes. Was.

Next, the mixed solution was poured into a mold composed of a glass lens molding die and a resin gasket, and was heated from 25 ° C to 120 ° C.
The temperature was raised continuously at 20 ° C for 20 hours, then at 120 ° C for 2 hours.
The polymerization was carried out while maintaining the time. After the polymerization, the gasket was removed, and the lens mold and the lens were separated to obtain a high refractive index polyurethane lens.

The obtained lens had good optical physical properties of n _d = 1.592 and v _d = 36.

(Preparation of Coating Solution) 54 parts by weight of a 0.06 N hot acid aqueous solution was added dropwise to 212 parts by weight of γ-glycidoxypropyltrimethoxysilane while stirring. After completion of the dropwise addition, the mixture was stirred for 24 hours to obtain a hydrolyzate.

Then, 424 parts by weight of antimony pentoxide sol (methanol-dispersed sol, average particle diameter 10 nm, fixed content 30%) and Denacol EX-521 (Nagase Kasei Co., Ltd., polyglycerol polyglycidyl ether) 34 as an epoxy compound
After stirring for 5 hours, 6.8 parts by weight of dibutyltin laurate was added as a curing catalyst, and further 100 parts by weight.
After aging for a time, a coating solution was obtained.

(Formation of a hard coat film) The high refractive index polyurethane lens produced by the above-described method was used.
After being immersed in a 10% NaOH aqueous solution at 50 ° C. for 5 minutes and sufficiently washed, a coating method is applied using the coating solution prepared by the above method, and a dipping method (pulling speed: 12 cm / min) is performed. After heating and curing for 1 hour, the mixture was gradually cooled to obtain a plastic lens with a hard coat.

(Formation of Multilayer Antireflection Film) Next, a sintered material of SiO ₂ was used as a deposition material for an underlayer and a low-refractive-index film provided on the plastic lens with a hard coat, and ZrO ₂ was used as a deposition material for a high-refractive-index film. Powder, Ta
₂ O ₅ powder and Y ₂ O ₃ powder were mixed at a molar ratio of 1: 1.3: 0.2, press-molded, sintered at 1200 ° C and pelletized, and the plastic lens described above was deposited. After placing in a tank and heating to 85 ° C. while evacuating, and evacuating to 2 × 10 ⁻⁵ Torr, the above-mentioned vapor deposition raw material was vapor-deposited on the plastic lens surface by an electron beam heating method, and as shown in Table 1, An underlayer composed of a silicon oxide film, a first low-refractive-index film composed of a composite equivalent film of a three-component vapor-deposited film and a silicon oxide film, a second high-refractive-index film composed of a three-component vapor-deposited film, and silicon A multilayer antireflection film having a film configuration in which a third layer of a low refractive index film made of an oxide film was sequentially formed was formed. Note that the underlayer was noticeably used to improve the adhesion to the substrate.

In evaluating the mechanical properties, chemical properties, and durability of these properties of the multilayer antireflection film formed as described above and the plastic lens having the multilayer antireflection film, the appearance of the lens, the scratch resistance , Adhesion, heat resistance, alkali resistance, acid resistance and weather resistance were evaluated and measured in the following manner.

-Appearance Using a lighting device using a fluorescent lamp as a light source, it was visually observed whether or not the following 1) to 4) were satisfied.

1) Be transparent.

2) The surface has no irregularities.

3) No striae.

4) No foreign matter or scratches on the surface.

-Luminous reflectance 380-780n using Hitachi 340 type self-recording spectrophotometer
The reflectance in the m wavelength region was measured, and the luminous efficiency was converted from the reflectance and the visibility curve.

Scratch resistance The surface of the multilayer antireflection film was rubbed with steel wool # 0000, and the scratch resistance was visually determined. The criteria were as follows.

A: Hardly scratched even if strongly rubbed.

B: If you rub it hard, it will be quite scratched.

C: The same damage as the lens substrate is made.

・ Shock resistance Anti-reflective property High refractive index 127c at the center of plastic lens
A 16 g steel ball was dropped from a height of m, and the lens was examined for damage.

・ Adhesiveness Cross-cut the lens surface with the multilayer anti-reflective coating at 100mm intervals at 1mm intervals, apply strong cellophane tape, peel off rapidly, and check whether the multilayer anti-reflective coating, underlayer and cured film have peeled off. Examined.

Heat resistance The lens provided with the multilayer anti-reflection film was placed in an oven for one hour and heated to check for cracks. The heating temperature was started from 70 ° C., increased by 5 ° C. in increments of 5 ° C., and the superiority was determined by the temperature at which cracks occurred.

-Alkali resistance A lens provided with a multilayer antireflection film was immersed in a 10 wt% NaOH aqueous solution for 24 hours, and the erosion state of the surface of the multilayer antireflection film was observed.

A lens provided with a multilayer anti-reflection film was immersed in an acid-resistant 10 wt% HC1 aqueous solution and a 10 wt% H ₂ SO ₄ aqueous solution for 3 hours, and the erosion state of the multilayer anti-reflection film surface was observed.

・ Weather resistance In order to examine durability, a lens provided with a multilayer anti-reflective coating was exposed outdoors for one month, and then the appearance, scratch resistance, adhesion, heat resistance, alkali resistance and acid resistance were evaluated as described above. ,It was measured.

As a result, in the multilayer antireflection film of the present example and the plastic lens having the multilayer antireflection film, favorable evaluation and measurement results were obtained for all items,
It was confirmed that the mechanical properties and chemical properties were excellent, and that these properties were excellent in durability.

Of these evaluation and measurement results, Table 2 shows the evaluation and measurement results of the eight items of appearance, luminous reflectance, scratch resistance, impact resistance, adhesion, heat resistance, alkali resistance and acid resistance.
Table 3 shows the weather resistance, that is, the evaluation results of the above eight items one month after outdoor exposure.

FIG. 1 shows the reflectance of the polyurethane lens having a multilayer anti-reflection coating obtained in this example, measured on both surfaces of the lens in the wavelength range of 380 to 780 nm using a Hitachi 340 type recording spectrophotometer. As shown in the spectral reflectance curve, it is confirmed that the plastic lens having the multilayer antireflection film obtained in this example has excellent antireflection characteristics with a luminous reflectance of 1% or less. Was.

[Effects of the Invention] As described above, the multilayer antireflection film of the present invention has excellent optical, mechanical, and chemical properties even when deposited at a relatively low temperature, and has these properties. Has excellent durability.

Therefore, by implementing the present invention, even for an optical element such as a polyurethane optical element that cannot raise the substrate temperature during the formation of the antireflection film,
By providing a multilayer anti-reflection film having excellent optical properties, mechanical properties and chemical properties, and excellent in these properties, it is possible to maintain the optical properties of the optical element at a high level for a long time. It becomes possible.

Further, the film design of the present invention can provide a low antireflection film, which is sometimes useful for polyurethane lenses having a high refractive index.

[Brief description of the drawings]

FIG. 1 is a spectral reflectance curve of a polyurethane lens having a multilayer antireflection film obtained in an example.

Claims (2)

(57) [Claims] 1. A multilayer antireflection film for a polyurethane lens comprising a low refractive index film and a high refractive index film alternately laminated,
Counting from the substrate side, the first layer has an optical thickness of 0.09λ to 0.
14λ, and a metal oxide film containing tantalum, zirconium and yttrium, and an optical film thickness of 0.04λ to 0.07λ
And a low refractive index composite film composed of a silicon oxide film, and the second layer has an optical thickness of 0.24λ or more.
0.23λ, a high refractive index film composed of a metal oxide film containing tantalum, zirconium and yttrium, and a third layer having an optical thickness of 0.24λ to 0.26λ and a low refractive index composed of a silicon oxide film An antireflection film for a polyurethane lens, comprising a film. 2. The method according to claim 1, wherein the metal oxide film containing tantalum, zirconium and yttrium contains Ta ₂ O ₅ per 1 mol of ZrO _2.
0.8 to 1.8 mol, Y ₂ O ₃ and is obtained by depositing 0.05-0.3 molar comprises mixing raw materials, polyurethane lens multilayer antireflection film according to paragraph 1 the claims.