JPH0237301A - Antireflection film - Google Patents

Abstract

PURPOSE:To improve an adhesive property and durability by laminating dielectrics on an antireflection film to constitute the antireflection film and forming a 1st layer of this antireflection film from the surface side of the antireflection film of a layer consisting of silicon dioxide. CONSTITUTION:The administration of the shape, weight and surface quality of a glass articles is important and significantly affects the characteristics and mass productivity of the molded antireflection film 1. Said glass element is subjected to an etching treatment in order to improve the surface roughness of the glass article. This antireflection film is constituted by laminating the dielectric materials on the antireflection film formed by press forming of the glass particle which is preliminary subjected to etching treatment. The 1st layer from the surface side of the antireflection film is constituted of the silicon dioxide. The antireflection film having the excellent adhesive property and durability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an antireflection film constructed by laminating a dielectric material on the surface of an optical press glass element made by press-molding a glass article.

BACKGROUND OF THE INVENTION In recent years, optical glass elements such as optical glass lenses are becoming more aspherical in order to simultaneously achieve simplification and weight reduction of the lens structure of optical equipment, as well as improved optical properties. When manufacturing this aspherical glass element, it is difficult to process and mass-produce it using the conventional manufacturing method, the polishing method.
Japanese Patent Publication No. 5438126) is considered to be promising.

In addition, no matter which manufacturing method the optical glass element is made in, in order to improve the optical properties, it is not possible to form an anti-reflection film by laminating a dielectric material on the surface of the optical glass element using a vacuum evaporation method or the like. This is known as a general technique. (For example, "Optical Technology Handbook" by Mr. Kubota et al.) Hereinafter, a conventional antireflection film for an optical glass element will be explained with reference to the drawings. FIG. 3 is a diagram showing a structure in which an antireflection film made of magnesium fluoride is formed on the surface of an optical glass element, and (C) of FIG. 780 nm) is a diagram showing spectral reflection characteristics when formed to a thickness of 780 nm. In Figure 3, l
5 is an optical glass element, and 5 is an antireflection film made of magnesium fluoride. The antireflection film 5 is generally formed by a vacuum deposition method.

Problems to be Solved by the Invention In manufacturing the above-mentioned optical glass elements, the image forming performance of the optical glass elements must be superior to that of optical glass elements produced by conventional polishing methods, and extremely high surface precision and Surface roughness is required. For example, in the case of a high-precision camera lens, the surface accuracy is required to be within five Newton rings or one candy, and the surface roughness is required to be 0.02 μm or less. Further, as optical equipment becomes smaller, it is desired to make optical components smaller and lighter, and conventional polishing methods cannot produce compact optical components in large quantities and at low cost.

The direct press method is attracting attention as a method for manufacturing high-precision optical glass elements. Among the direct press methods, the reheat press method is particularly suitable for manufacturing highly precise optical glass elements.

The reheat press method is a method in which a glass article having a surface shape similar to a desired optical glass element is made, the glass article is heated and pressurized in a mold, and then cooled and the molded optical glass element is taken out. . In this reheat press method, the shape, weight, and surface quality of the glass article are important, and these have a large effect on the characteristics of the molded optical glass element.

A common method for manufacturing glass articles is to grind a glass material using a curve generator and then polish it to make the surface smooth. Although polishing can provide a finish with good surface precision, it is difficult to process glass articles with a small radius of curvature with good mass production, resulting in high costs. In addition, if a glass article is press-molded after the glass material has been ground using a curve generator,
Because fine irregularities on the surface of glass articles remain without disappearing,
The transmittance of the optical glass element deteriorates and the optical performance deteriorates.

For this purpose, in order to remove minute irregularities on the surface of the glass article, a process consisting of immersing the glass article in an aqueous hydrogen fluoride solution, washing with water, and removing moisture is repeated as an etching treatment. It is carried out.

However, when the conventional anti-reflection film is formed on an optical glass element manufactured by directly pressing a glass article treated by the above process, this anti-reflection film has poor adhesion to the optical glass element and has poor durability. They also had the problem of low gender.

In view of the above-mentioned problems, the present invention provides an antireflection film with excellent adhesion and durability for an optical glass element made by press-molding a glass article subjected to the etching treatment.

Means for Solving the Problems In order to solve the above problems, the present invention provides an anti-reflection film formed by laminating a dielectric material on an optical glass element, comprising:
The anti-reflection film is characterized in that the first layer from the surface side of the optical glass element is a layer made of silicon dioxide.

Function: As mentioned above, the direct press method is attracting attention as a method for producing high-precision optical glass elements in large quantities and at low cost. Furthermore, the reheat press method is said to be suitable for manufacturing highly precise optical glass elements.

What is important in the reheat press method is the shape of the glass article,
Weight and surface quality are controlled, and these have a great impact on the properties and mass productivity of molded optical glass elements.

Etching treatment is performed to improve the surface roughness of glass articles.

The present invention provides an anti-reflection film formed by laminating a dielectric material on an optical glass element made by press-molding a glass article that has been previously subjected to an etching treatment, the anti-reflection film comprising a surface of the optical glass element of the anti-reflection film. The first layer from the side is a layer made of silicon dioxide to provide an antireflection film, and as a result, an antireflection film with excellent adhesion and durability can be obtained.

EXAMPLE Hereinafter, an example of the antireflection film of the present invention will be described with reference to the drawings.

The glass used was lead glass SF8, and the glass material had a radius of curvature of 3.5 mm and 2.9 mm, and an edge diameter of 6.5 mm.
It was ground into a biconvex shape with a thickness of 3 mm and a wall thickness of 4 cores of 8fflI11. The glass article thus obtained was immersed in 10% hydrofluoric acid at a liquid temperature of 40°C for 10 seconds, and then soaked in distilled water for 3 hours.
The glass articles were washed for 15 minutes and then dried for 15 minutes in a dryer kept at 200''C. The glass article was press-molded using a mirror-finished mold.The molding conditions included a mold temperature of 52
The 0'C1 molding pressure was 10 kg/c+a, and the molding time was 2 minutes. Silicon dioxide is applied to the press-molded optical glass element by vacuum evaporation at an optical film thickness of λo/
4 (λo=780 nm). FIG. 1 is a diagram showing the structure of an antireflection film in a first embodiment of the present invention, and FIG. 4(a) shows its spectral reflection characteristics. In FIG. 1, 2 is a first layer made of silicon dioxide.

A test was conducted to compare the adhesion and durability of the anti-reflective film of the example of the present invention and a conventional anti-reflective film.
1) Adhesive tape peeling test (temperature 40'' C1 relative humidity 85
% in a high temperature atmosphere for 300 hours, adhere the adhesive tape to the surface of the optical glass element and peel it off) (
2) Humidity test (temperature: 60°C, relative humidity: 85%)
The conventional anti-reflection film for comparison is one of the conventional examples, which is an anti-reflection film of magnesium fluoride applied to an optical glass element by vacuum evaporation. It is formed to a thickness of λo/4 (λo=780 nm) and has the structure shown in FIG. The results of the adhesion and durability tests are shown in Table 1.

Table 1 As can be seen from Table 1, the antireflection film of the present invention is an antireflection film in which the first layer from the surface side of the optical glass element is made of silicon dioxide, and has better adhesion and durability than conventional antireflection films. Excellent in terms of sex.

A second embodiment of the present invention will be described below with reference to the drawings. The optical glass element used in this example is made of the lead glass SF8 described above, and is an optical glass element molded by the same process described above.

FIG. 2 is a diagram showing the structure of an antireflection film in a second embodiment of the present invention, and FIG. 4(b) shows its spectral reflection characteristics. In FIG. 2, 2 is a first layer made of silicon dioxide, 3 is a second layer made of aluminum oxide,
4 is a third layer made of titanium dioxide, 5 is a fourth layer made of magnesium fluoride, and the optical thickness of each layer is λo/4°λo/4. λo/2. λo/4(λo=
780 nm).

The anti-reflection film of the second example of the present invention was also subjected to the adhesive tape peel test and moisture resistance test, and as with the first example, no abnormalities were found.

Further, as can be seen from FIG. 4, the spectral reflection characteristics of this embodiment are superior to the conventional example over a range from about 600 nm to 11100 nm.

The thickness of the anti-reflection film in the first and second embodiments is not particularly limited to the above values, and may be changed depending on the design wavelength, and the thickness of the anti-reflection film can also be changed as desired. Any value may be used as long as the first layer from the surface of the optical glass element is made of silicon dioxide.

Effects of the Invention As is clear from the above explanation, the antireflection film of the present invention is constructed by laminating a dielectric material on an optical glass element that is made by press-molding a glass article that has been etched in advance. By composing the first layer from the surface side of the optical glass element with silicon dioxide, it is possible to obtain an anti-reflection film with excellent adhesion and durability, and its practical value is There is something big about it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an anti-reflection film in a first embodiment of the present invention, FIG. 2 is a block diagram of an anti-reflection film in a second embodiment of the present invention, and FIG. 3 is a diagram of a conventional anti-reflection film. 1... Optical glass element, 2... Layer made of silicon dioxide, 3... Layer made of aluminum oxide, 4... Layer made of titanium dioxide, 5
・・・・・・A layer made of magnesium fluoride. Name of agent: Patent attorney Shigetaka Awano 1 person 1 - Optical glass element 2 - 1 made from coral fluoride made from 2 groups and silicon 1 r

Claims (2)

[Claims] (1) An anti-reflection film formed by laminating a dielectric material on an optical glass element made by press-molding a glass article that has been subjected to an etching process, the anti-reflection film being formed on the surface of the optical glass element. An antireflection film characterized in that the first layer from the side is a layer made of silicon dioxide. (2) The antireflection film according to claim 1, wherein the etching treatment comprises the steps of immersing the glass material in an aqueous solution of hydrofluoric acid, washing with water, and removing moisture.