JPS58162901A - Plastic optical element - Google Patents

Abstract

PURPOSE:To constitute a titled element so that its surface accuracy and refracted index are not varied even if the environmental condition is varied, by providing a hydrophobic thin film on the surfaces of an optical element by a plasma polymerizing method. CONSTITUTION:On the surface of a base board of an optical element consisting of a resin composite whose coefficient of water absorption by ASTMD-570 is >=0.15%, for instance, a lens, a prism, a reflector, an optical fiber, etc., a hydrophobic thin film is formed by a plasma polymerizing method. For instance, a lens (thickness of the center part is 3mm.) obtained by inject-molding polymethyl methacrylate resin is dried at 50 deg.C for three days, and thereafter, a plasma polymerized film of octafluorocyclobutane is formed under the conditions of 70 deg.C base board temperature, 13.56MHz discharge frequency, 10W high frequency power, 0.1Torr pressure, and such an element is made to absorb water under the conditions of ASTMD-570, 23 deg.C, 100% RH and 24hr, and as a result, its coefficient of water absorption is 0.08% and remarkably below 0.28% of an untreated lens.

Description

[Detailed description of the invention] #4#i optical resin of the present invention! II! The surface of the substrate of an optical element made by molding an object is coated with a hydrophobic light and thin layer using special electropolymerization method.
The present invention relates to an improved plastic optical element formed by forming an optical element.

Our plastic optical elements include so-called lenses for still cameras, video cameras, telescopes, II-lens lenses, hard contact lenses, solar light and other lenses, as well as lenses such as Benme prisms. -1 Concave blood mirrors, mirror plates such as polygons, optical fibers, light guide elements such as optical waveguides, disks such as optical 7+JT video disks, audio disks, etc., which perform their functions by transmitting light.

Such plastic optical elements are made of styrene-T-crylonitrile co-topolymer, polymethyl methacrylate Aijima, polycarbonate resin, etc.O general-purpose resin is used as optical resin.
In recent years, there has been a huge demand for i+, as it has been manufactured and is noisy, and mass production is required. is increasing.

However, due to the resin properties of conventional plastic optical elements made of general-purpose resins, the characteristics of the optical elements change due to changes in environmental conditions due to the resin's high water absorption, making the optical system unstable. , was a problem.

? Optical elements molded from polymethyl methacrylate L7S have excellent optical U characteristics, but they have high water absorption and are highly water-absorbing. # - A friend that has the disadvantage of a large change in surface quality 1 and a large change in refractive index.

Ji! Since then, we have discovered that by forming a hydrophobic thin film on the surface of the substrate of an optical element by plasma polymerization, water absorption can be improved and the optical properties of the optical element can be stabilized.

An object of the present invention is to provide an optical element that does not exhibit distortion or change in refractive index due to changes in environmental conditions by providing a hydrophobic thin film using a specific polymerization method.

It is an object of the present invention to coat the surface of the base 110 of an optical element with a l1firffi product tFfL having a water absorption rate of 0.15 or more by Mu8TMD-570, formed by the plasma 1 method, with an icephobic property. This is achieved by a PLUSDEC optical element which is characterized by a thin tube.

According to a preferred embodiment of the present invention, the thickness of the hydrophobic thin film formed by plasma polymerization is 5 nm to 2000 m, and the water vapor permeability of wrinkle thinning is 111 g, 020 g, 40 g.
℃, Ru2O, 200 g/j under the conditions of 305 m thickness
/24 hr or less, and the thin @ is provided as at least one layer of a multi-layer thin film, and the refractive index of each layer is 14.

According to another preferred embodiment of the solid line, the surface hardness after forming a hydrophobic thin layer by the plasma 11 of the present invention is J.
lBK-5651 with lead wire hardness of 2H to 10H1 preferably t
It is 14H to 8H.

If there is a change in the surface precision of an optical element or a change in the refractive index due to environmental changes, the characteristics of the entire optical system become unstable and the reliability of the optical element decreases. Therefore, by forming the hydrophobic thin film of the present invention, improving the water absorption resistance 1r and improving the optical property stabilization will yield extremely overlapping results.

The method of forming hydrophobic *m'i by plasma polymerization is, for example, placing an optical element substrate in a reaction tank in d% high polymer.
A thin S-forming material, for example λ, is a gas such as chlorofuran gas, chlorofluorocarbon gas, hydrogen gas, etc., and monomers such as sunalene, vinylidene chloride, eteledene, dodisdene fluoride, acrylonitrile, etc. are introduced into the reaction tank. A high-pressure discharge is carried out in the process to form a high-temperature ionized gas state, causing the mixed sludge or monomers to react with each other. The resulting reaction product is deposited and fixed on the optical element group Table Ik to form a layer, forming the hydrophobic thin film of this @ Ming.

Thin m forming material 't*K
Then, it can be made into multiple layers by making it thin II [1 tatami mat].
By forming a multilayer film on the surface of the optical element, an optical element having optically improved characteristics can be obtained. Depending on the material and thickness of this multilayer film, it has the property of exhibiting selectivity to transmitted light, and can improve the color balance of transmitted light and the generation of reflected light.

The present invention (Basic II material for optical elements in which the plasma-polymerized hydrophobic thin film of the present invention is an extremely suitable means of protection against humidity, etc. that fluctuates due to changes in environmental conditions) /C can sufficiently improve the water absorption resistance.If at least one layer of the multilayer film is a hydrophobic thin film formed by the present I&Qo plasma combination, the optical property of the present &jLl ft-shaped element can be The characteristics are clearly improved.The hydrophobicity of this newly developed W!# can be in any location, and the outermost layer is essential for trout.

Here, the water absorption rate is expressed in accordance with the ASTM D-570 standard. Element base used in the plastic optical element of the present invention: IjIFi; a resin composite acid having a relatively high water absorption rate of 0.15 or more (e.g., polymethyl methacrylate resin, BO1'' carbonate) resin, sunalene-acrylonitrile resin, etc. polymers etc. )? Although it is formed by molding, it is a hydrophobic thin film formed by plasma polymerization according to the present invention.
It fully demonstrates its 1IIA capabilities and effects.

Hydrophobic thin film produced by plasma polymerization of the present invention with a thickness of 5 nm
~2000nm, more preferably 1100n~500nm
It is desirable to be fim. Below 5 nm, 4 is hydrophobic, that is, water vapor impermeability is difficult to get dusty, while 20
If it exceeds 00 nm, even if the water absorption resistance and water vapor impermeability are good, depending on the material '/#F, the color may appear and the light transmittance etc. will decrease, making it unsuitable. Water vapor permeability is used as the hydrophobic property, but one method specified by JI8Z (1208) is 40°C, 90 whisper Rf (200 g/m'/24 hours or less at a thickness of 30 pm, Especially 7ml for 20
/24 hours or more is desirable.

The self-am of the lens can be found by subtracting the number of changes in Newtonian cylinder 0 in relation to the standard curvature surface using the Gengakucho method. In addition, the surface of the thin film formed on the surface of the -yts#J element is excluded from practical use, and in order to have durability, the lead wire specified in JISK585.1 must be
~108. Preferably, 4H to 8H exhibits sufficient functionality.

Also, the surface resistivity of the thin film, t-IJIBK69, which was underestimated.
If it is less than lXl0 Ω, preferably less than lXl0 Ω, the lens surface fiO
C)K is effective in preventing electrical problems and the accumulation of dust, etc.

The substrate used in the optical element of the present invention may contain ultraviolet absorbing steel for light resistance. As for the ultraviolet absorbing steel, it is fine as long as it does not reduce the transmission rate to the cil viewing range, and it does not degrade other resin properties, but even if it does not degrade the properties of other resins, for example, do-hydro medium? LJ? A=acid phenyl compound, 0-hydroxybenzo2enone compound, 2-(o
-hydro-diphenyl)-benzotriazole thread compounds, cyanoacrylate thread compounds, etc. can be used.

In addition, as heat stabilizers, 2,6-di-tert-butyl-p-cresol, 2,4-di-methyl-6-tert-butylphenol, 2,2'-methylenebis(4-methyl-6-#!
3pnarphenol), 4.4'-1teridenebis(3
-methyl-6-tert-butylphenol), 4,4'-naobis(3-methyl-6-tert-butylphenol), 1
．． 1.3-Tris(2-methyl-4-hydro-5-
m-tributyl-2-enyl)butane, below blank H CH3t-teiU (R: C1g7-C, Peng's alkyl group), di-lauryl theodiglobionate, distearyl naodifuropionate, distearyl β, β '-Teosibunarate, ()-o-P(-0-Cl0H21)2, (○toO÷2P-0-CIOH21%pro Cl0H21)
5 etc. may be contained.

It may contain a plasticizer to improve the fluidity during molding. Examples of arm agents include alkyl phthalates such as 2-enalhexyl phthalate, n-7 terphthalate, indecanyl phthalate, tridecanyl 2-talate, heptyl phthalate, and nonyl phthalate;
- Dibasic alkyl esters such as ethylhexyl adibate, sebacic acid, 2-ethylhexyl, tributyl phosphate, trioctyl phosphate, phosphoric acid) +3 cresyl, tri2enyl phosphate, phosphoric acid) +4 xylenyl glue, etc. Epoxidized fatty acid esters such as alkyl esters, epoxidized octyl oleate, and butyl oleate, other polyesters, chlorinated fatty acid esters, and other substances that function as plasticizers. If so, you can use anything. Also, two or more of these may be used in combination. In addition, as m-shaped steel, silicone oil, dimethylpolysiloxane, polysiloxane, aliphatic 20-carbohydrate, 1% lump or solid back-in, bunalazide phosphate, butoxyethyl Tzidphos2ate, 2-ethyl to medium silane fluoride phosphate, di(2-ethyl)phosphate, ethylene glycol phosphate, (2- and droxy7)
Ether) memethacrylate/T-dide phosphate group [
May contain.

The plastic optical element oim of the present invention may be of any type. For example, injection ready-made method, pressure 5WL
The W method or a compromise method of injection layering and compression molding, such as the Rawlinx method, 1 micromolding method, etc.
Any method of making 1 lil S-solid or semi-molten to aaV can be applied.

Hereinafter, based on actual examples, the present invention will be explained in detail. To clarify,
The present invention is not limited to this. In addition, the following dice #1
In a box, "parts" and "parts by weight" are used.

Practical example 1 Polimenarume! Kudozo A-taki lens obtained by injection and distillation of acrylate resin (thickness of 3 parts in the center) t''
After drying at 50 C for 3 days, octafluoron crop was applied to this under the following conditions. A plasma blood mixture IIt was formed.

[Plasma polymerization conditions]

Base Mltlf 70°C, discharge wave number 13.56, high-wave power 10W, pressure C1, I Torr.

The plasma iris thin 110 mIIU10 formed in this way
0 nm), refractive index Fi1.42, Table 110 Hardness 1
j was 4H, and the surface resistivity was 2 x 10''Ω.

In this way, both sides of the resin of the present invention were coated with a thin film.
℃.

When the lens was allowed to absorb water for 1.24 hours, the water absorption rate was 0.084, which was significantly lower than 0.28% of the untreated 1IIi1 lens.

Father, put the bottom cover lens on Tree 1 of the present invention at 75℃ and 100%RH.
v) My friend asked me to leave it for 6 hours under the conditions! [No change in tX was observed and there were zero Newton rings, but in the untreated m* resin molded lens, tS occurred in which the number of Newton rings changed by 3 to 2, and a significant change in quality was observed.

Practical pole @2 A dried Tsukuda-containing lens obtained in the same manner as in Practical pole example 1 was coated with plasma-enriched thin fusuma of the monomers of Table 1 12) A-F under the following conditions. [Conditions for one plasma] Base 11a11j 60C, radiation 14m number 13.56MHz
,a Same wave power 10W1 pressure 0.05'I”orr.

The water absorption rate comparison results are shown in Table 1.

As is clear from Table 1 below, it can be seen that dud #U can improve water absorption and prevent changes in face quality due to environmental changes.

Patent applicant: Konishiroku Photo Industry Co., Ltd., agent patent attorney
Nobuaki Sakaguchi (11 or 1 person)

Claims (1)

[Claims] Water absorption rate by Mu87MD-570&C is 0.15 or more O
Table h of the base of an optical element made by removing the Mi product.
K, hydrophobic thin II formed by plasma 1 method
A plastic optical element having a characteristic of LkVr.