JPS60144702A - Antireflecting optical element - Google Patents

Abstract

PURPOSE:To obtain an antireflecting film having durability by forming the innermost layer of the multilayered antireflecting film of a mixed film contg. at least yttrium oxide and zirconium oxide and the outermost layer of a film consisting of silicon dioxide. CONSTITUTION:A synthetic resin substrate subjected to surface hardening treatment is first subjected to cleaning of the surface by using an ordinary multi- stage cleaning device using Freon and is thereafter formed thereon with the three-layered antireflecting film consisting of a mixed film contg. zirconium oxide/yttrium oxide=40/60 (by wt.) as the 1st layer from the substrate side, the film contg. titanium oxide as the 2nd layer and the film contg. silicon dioxide as the 3rd layer by using a vacuum deposition device provided with an electron beam gun. The vapor deposition temp. is 80 deg.C. The surface reflecting interference color of the resulting antireflecting film is magenta and the reflectivity of visible rays is as low as about 0.5%. The adhesion between the antireflecting film and the surface hardened film is accepted in a peeling test by using a cellophane tape. The film is just slightly flawed in the surface hardness test involving rubbing with steel wool. Thus the antireflecting film exhibits excellent performance.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] [9] The present invention first forms an organic or inorganic surface hardening film on a synthetic resin base material, and then forms a multilayer antireflection film under vacuum. The present invention relates to an optical element obtained, and relates to an antireflection optical element that simultaneously satisfies excellent antireflection properties and excellent physical properties such as surface hardness and film adhesion.

[Conventional technology]

Polymethyl methacrylate, polycarbonate.

Cellulose acetate, cellulose acetate v
-), cellulose acetate propione).

Thermoplastic and thermosetting synthetic resins, such as polyethylene terephthalate and diethylene glycol bisallyl carbonate polymers, are known for their transparency.

By taking advantage of its characteristics such as lightness, impact resistance, ease of molding, and dyeability, it is used in lenses, prisms, selective absorption transmission and reflection filters, cover glasses, etc. that transmit, absorb, and refract light.
Its use as a high-performance optical element that utilizes reflection is increasing. The reason why the application of optical components based on synthetic resins is increasing in this way is the development of various surface hardening treatment techniques to overcome the softness of the surface, which is a drawback of synthetic resins, and the transmission, absorption, and reflection of light rays. There has been progress in forming various inorganic thin films that can be rolled on sound controls.

Various specific techniques have been proposed to date to prevent scratching and improve chemical resistance by hardening the surface of synthetic resins. Acrylic curing paints, which are typified by the technology of curing reactants such as acrylic acid or methacrylic acid and propylene oxide or alkyd resins with ultraviolet rays or electron beams, and melamine based on alkyl etherified methylol melamine, belong to system treatments. Amine type curing amount F4, which is typified by alkyd resin type. Ethylsilicate, methyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, γ-
There are thin films made of organopolysiloxane-based curing paints that use glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyljethoxysilane, etc. as representative silicon compounds, and they also belong to inorganic systems.

There are hard thin films made by vacuum deposition using Sin, low melting point glass, etc., and applied products that take advantage of the characteristics of each have been commercialized. - Regarding the formation technology of inorganic thin films to form multilayer anti-reflection coatings on the surfaces of lenses, such as camera lenses and eyeglass lenses, in order to improve the practical performance of optical components based on Kada 1 synthetic resin.

Various findings have been obtained. As a low refractive index material used on the synthetic resin base material for anti-reflection.

Due to the heat-resistant temperature limit of the base material, it is not suitable to use magnesium fluoride, which is commonly used in the case of glass profiteers, so silicon dioxide is used because it can provide a deposited film with excellent hardness even under low-temperature deposition conditions. This is well known. or. It is well known that inorganic oxides, which have been conventionally used for antireflection of glass substrates, can be used as high refractive index substances essential for forming multilayer antireflection films. Examples include zirconium oxide, titanium oxide, cerium oxide, indium oxide, hafnium oxide, and tantalum oxide.

Furthermore, materials for forming intermediate refractive index layers that are necessary for forming high-performance anti-reflection coatings are selected in conjunction with the designed high refractive index layer: - silicon oxide, zirconium oxide, aluminum oxide. .

Examples of using yttrium oxide, etc. are known (Japanese Patent Publication No. 56-15481; Japanese Patent Publication No. 56-18922).
). To give a specific example of a three-layer anti-reflection film,
In order from the profiteering side, the first layer (intermediate refractive index)/second layer (high refractive index)/third layer (low refractive index) includes Al, 0. /
ZrO, / Sin, , SiO/Tie, /
Sin, , Al, O, / CeO, / Sin,
, , Y,O,/ZrO,/Sin, , Y,0.
/ Tie, / Sin, , Y, 0. /Ce
O,/Sin, , Y,0. /Eng No, /S
in, , Y, 0. /HfO, /Si,0. ,
SiO/ 2rO,/Sin, , ZrO,/T
ie.

etc.

This is because the anti-reflective coating is an extremely thin layer.

When a synthetic resin is used as a base material, it is difficult to obtain a long-established anti-reflection film by directly applying an anti-reflection film treatment to the surface. For this reason, durable reflection 1
A known method for obtaining a υj stop film is to first form an organic or inorganic surface hardening film on a synthetic resin base material, and then form an antireflection film.

[Purpose of the invention]

The purpose of the present invention is to create a synthetic resin base material that stably satisfies the ideal anti-reflection design, which has been difficult with conventional technical knowledge, and that also has excellent practical performance such as film adhesion and surface hardness. A new multilayer antireflection coating composition is provided that is effective for having antireflection optical elements.

[Structure of the Invention] The present invention provides an antireflection optical element in which a surface hardening film is first formed on at least one surface of two synthetic resin base materials, and a multilayer antireflection film is formed thereon. This is an antireflection optical element characterized in that the innermost layer of the film is made of a mixed film containing at least yttrium oxide and zirconium oxide, and the outermost layer is made of a silicon dioxide film.

When performing anti-reflection treatment under vacuum using a synthetic resin base material, due to the limitations of 9. Physical Properties of Synthetic Resins, practically usable vapor-deposited materials with low and high refractive indexes, such as when using an all-glass base material, are used. It is not possible to make a wide selection. For this reason, it is increasingly difficult to find a practical vapor deposition material having an intermediate refractive index necessary for forming an ideal antireflection film among known mushrooms. Conventionally known silicon monoxide, aluminum oxide, zirconyl oxide, IJium oxide, etc., have large fluctuations in refractive index and coloration due to fluctuations in deposition conditions, and are not suitable for ideal anti-reflection conditions. The problem is that the refractive index is too low or too high.

The present invention [As a method for stably obtaining an intermediate refractive index under low-temperature deposition conditions of 120'O or less, we focused on the combination of deposition materials that can be mixed and examined, and found that yttrium oxide and zirconium oxide Rammura are the main components. It was completed by discovering that mixed vapor deposition is very effective. In addition, as a result of forming a multilayer anti-reflection film using the intermediate refractive index layer according to the present invention using synthetic resin base materials subjected to various organic and inorganic surface hardening treatments, improvements in film adhesion, surface hardness, etc. It was confirmed that the practical characteristics were also extremely excellent. Until now, there has been no proposal to use yttrium oxide or zirconium oxide alone as an intermediate refractive index layer. The refractive index of a film formed from a mixed film of yttrium oxide and zirconium oxide can be controlled by adjusting the oxygen introduction conditions during vacuum processing, etc.

Continuously variable between about 17 and 1.9. Furthermore, it is also possible to partially mix aluminum oxide, titanium oxide, etc. for the purpose of increasing the vertical range of the refractive index or improving stability during vapor deposition. A low refractive index substance is used for the outermost layer of the anti-reflection film, but when using synthetic resin as the base material, it is impossible to keep the heating temperature during vapor deposition to the same temperature as when using a glass base material. Therefore, it is recommended to use silicon dioxide to form a durable antireflection coating. In addition, as the high refractive index material for forming the anti-reflection layer, there are various conventionally known materials,
For example, zirconium oxide, titanium oxide, cerium oxide, indium oxide, hafnium oxide, tantalum oxide, etc. can be used alone or in combination.

First, an organic surface hardening film is formed on the synthetic resin base material 9
Next, when an antireflection film is formed under vacuum, it is also the significance of the present invention to coat an inorganic substance on the organic cured film under vacuum in order to improve physical properties or produce an effect such as coloring before forming the antireflection film. It does not cause any loss. In order to further strengthen the adhesion between the thin organic surface hardening film and the first layer formed under vacuum, it is also meaningful to perform a surface treatment on the surface hardening film in advance.Surface treatment method Various chemical, physical, or mechanical methods can be employed for this purpose, and two examples include alkali treatment, acid treatment, discharge treatment, plasma treatment, and sandblasting.

As an anti-reflection film formation technology under vacuum.

It is possible to apply a sputtering method or the like alone or in combination.

Next, a concrete explanation will be given using examples.

Example 1 A commercially available “Acrylite A R” manufactured by Mitsubishi Rayon (thickness approx. 21T111
1. Polymethyl methacrylate cast plate coated with a polyfunctional acrylic resin cured coating. Composition of cured coating film
,]j+SCA and FT-JR analysis method)'fl: Obtained. First, the surface of this base was cleaned using a normal Freon multi-stage cleaning device, and then a vacuum evaporation device equipped with an electron beam gun was used to coat zirconium oxide/yttrium oxide-4 as the first layer from the substrate side.
A three-layer antireflection film (film composition of λ/4°λ/2.λ/4) was formed by combining a mixed film of 0760 (weight ratio), a second layer, titanium oxide, a sixth layer, and silicon dioxide. The deposition temperature was 80°C, 1 difference.

The surface reflection interference color of the obtained anti-reflection treated plate is magenta, the visible light reflectance is excellent at approximately 0.05%, and the adhesion between the anti-reflection film and the surface hardened film passed a peel test using cellophane tape. The surface hardness test by steel wool rubbing (+00oo grit) showed excellent performance with only slight scratches. Note that zirconium oxide alone is the first
When used as a layer, the refractive index was too high, and when using yttrium oxide alone, the refractive index was too low, so it was difficult to bring the visible light reflectance to the 0.5 factor level.

Example 2 A silicone-based surface hardening agent whose main components are a hydrolyzate of γ-glycidoxypropyl methyljethoxysilane, an epoxy resin, and a silica sol (as shown in JP-A-56-74202. Example 2) ), a lens-shaped molded product (thickness approx. 2 mm) of polycarbonate resin ("Lexan" 141) obtained by injection molding, f-coated, 130
A resin base material with a surface hardening film was obtained by heat curing at °C for 2 hours.

Next, put this wood into a plasma reactor.

Surface activation treatment was performed in an oxygen gas atmosphere.

Next, as in Example 1, the surface of the substrate was cleaned by Freon cleaning, and then a vacuum evaporator was used to coat the substrate with 'Zubstance 1'' (deposition chemicals manufactured by Merck Japan) as the first layer from the substrate side. , mixture of zirconium oxide and titanium oxide)/yttrium oxide = 65/35 (weight ratio)
mixed film, second layer.

A three-layer antireflection film (λ/4.λ/4.λ/4 film configuration) was formed by combining tantalum oxide, the sixth layer, and silicon dioxide. The deposition temperature was 100°C. The surface reflection interference color of the obtained anti-reflection treated product is a green IJ-green color, the visible light reflectance is excellent at about 07, and the adhesion of the anti-reflection film has passed a peel test with cellophane tape. In the surface hardness test by rubbing with steel wool (#0000), almost no scratches were observed, showing excellent performance.

EXAMPLE A cast polymer (lens shape with a thickness of about 2 mm and a diameter of about 70 strokes) was prepared using diethylene glycol bisallyl carbonate. Next, in the same manner as in Example 1, the surface of the polymerized amount was completely cleaned by Freon cleaning, and then
A layer of silicon dioxide was applied to a thickness of approximately 2 microns using a vacuum evaporator. This layer has the effect of improving the surface hardness of the polymerized synthetic resin and preventing scratching. Subsequently, in a vapor deposition tank, a mixed film of zirconium oxide/yttrium oxide-sD/so (weight ratio) was formed as a first layer.

Next, a two-layer anti-reflection coating (λ/
4. λ/4 film configuration) was formed. The deposition temperature was 80°C. The surface reflection interference color of the obtained anti-reflection processed product is a strong magenta color, and the visible light reflection rate is approximately 0.4%.
Moreover, the adhesion of the anti-reflection film passed a peel test using cellophane tape, and the adhesion of the anti-reflection film passed a peel test with steel wool (-#, 00
In the surface hardness test using No. 00), it showed excellent performance with almost no scratches.

Patent applicant: Toshi Co., Ltd.

Claims (1)

[Scope of Claims] An antireflection optical element comprising a surface hardening coating first formed on at least one surface of a synthetic resin base material, and a multilayer antireflection coating formed thereon. An antireflection optical element, wherein the innermost layer of the multilayer antireflection film is made of a mixed film containing at least yttrium oxide and zirconium oxide, and the outermost layer is made of a silicon dioxide film.