JPS6212882B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an antireflection film provided on the surface of a transparent synthetic resin optical component (hereinafter abbreviated as optical component).

A conventional antireflection film for an optical component basically has a film as shown in FIG. In other words, optical parts are manufactured using SiO ₂ in order to improve the surface hardness and solve the drawback of synthetic resins that they are easily scratched.
A relatively thick surface hardening layer 11 is provided, and an antireflection layer 12 is provided thereon.

The anti-reflection layer 12 has a two-layer structure, as shown in FIG. or as shown in Figure 3.
On the surface hardening layer 31, high refractive index material layers 32, 3
A four-layer structure in which two layers of low refractive index material layers 33 and 35 are alternately provided is known, but in general, a four-layer structure with good antireflection properties is mainly used. There is. Various high refractive index materials and low refractive index materials are used to make up these anti-reflection films, but especially in the case of optical components made of synthetic resin, adhesion is important when coating the anti-reflection film. Since it is impossible to heat the coating to improve its properties, the materials that can be used are limited to those that can provide sufficient adhesion even when coated at room temperature.

An antireflection film that satisfies these conditions and has good properties is a layer of high refractive index material containing ZrO ₂ .
A typical example is one using SiO ₂ for the low refractive index material layer.

For example, the anti-reflection film proposed by the present invention in Japanese Patent Application No. 53-126607 (see Japanese Patent Application Laid-Open No. 55-52001, hereinafter referred to as the "prior application") was applied to the surface of eyeglass lenses made of diethylene glycol carbonate. An anti-reflection film with a film structure as shown in Figure 3 is formed, and when the center _wavelength
On top of the μm SiO ₂ film, an optical film thickness of 0.07λo is added.
SiO ₂ film stacked), high refractive index layers 32 and 34,
The optical film thickness is 0.07λo and 0.52λo, respectively.
The ZrO ₂ film and the low refractive index layers 33 and 35 are SiO ₂ films with optical thicknesses of 0.09λo and 0.25λo, respectively, and with this film configuration, antireflection properties with a reflectance of around 1% are obtained. ing.

As described above, antireflection coatings using SiO ₂ and ZrO ₂ have the advantage of providing good antireflection properties and being able to be coated at room temperature, but the low refractive index material of the top layer The durability of the layer is not necessarily good, and phenomena such as a decrease in film hardness and peeling of the film occur, especially in a high-humidity atmosphere, and the film has the drawback of poor moisture resistance.

The present invention has been made to improve such drawbacks, and its purpose is to improve the durability and moisture resistance of the conventional antireflection film without changing its antireflection properties as described above.

The antireflection film of the present invention is characterized in that an extremely thin layer of Al ₂ O ₃ is provided below the topmost SiO ₂ layer.

If the thickness of the Al ₂ O ₃ layer is less than 1 nm, no effect of improving moisture resistance will be obtained, and if it exceeds 10 nm, the antireflection properties will change, so it is desirable that the thickness be within the above range.

Moisture resistance can be improved with other substances other than Al ₂ O ₃ by increasing the film thickness, but at the same time the properties as an anti-reflection film will also change. A thin film of Al ₂ O ₃ with a thickness of 1 nm to 10 nm is optimal as a substance capable of improving properties.

A detailed explanation will be given below based on examples.

Example An antireflection film as shown in FIG. 4 was coated on both sides of a diethylene glycol carbonate eyeglass lens with a power of +6D and a diameter of 65mm by vacuum deposition. 40 is a spectacle lens which is an optical component; 41
is a surface hardening layer of SiO ₂ with a thickness of 1 μm, 42
is the first high refractive index layer made of ZrO ₂ and has an optical thickness of 0.07λo when the center wavelength λo is 750 nm. 43 is a first low refractive index layer made of SiO ₂ with an optical thickness of 0.09λo, and 44 is a layer with an optical thickness of 0.52λ.
_{45 is a layer of Al 2 O 3} with a film thickness of 5 nm, and 46 is a layer with an optical thickness of 0.25λ.
The second low refractive index layer is made of SiO ₂ with a thickness of 4.
The film structure is the same as that of the antireflection film of the earlier application described above, except that a layer 45 of Al ₂ O ₃ is provided under the antireflection film 6 .

In addition, as a comparative example, like this example, it is made of diethylene glycol carbonate and has a +
Both sides of a 6D eyeglass lens with a diameter of 65 mm were coated with an antireflection film having the same film structure as the previous application as shown in FIG. 3 under the same conditions as in this example.
However, the thickness of the surface hardening layer 31 was set to 1 μm as in this example for comparison. high refractive index layer 32,
The material and optical film thickness of 34 and the low refractive index layers 33 and 35 are the same as in this example and the previous application.

When the two types of lenses thus obtained were immersed in hot water at 70°C for 90 minutes, the anti-reflection coating on the convex side of the comparative eyeglass lens peeled off in a 15mm width around the periphery. No abnormality was observed in the spectacle lens of this example. Note that no abnormality was observed in either lens on the concave side. Further, the spectral reflection characteristics of the antireflection film according to this example were as shown in FIG. 5, and the antireflection characteristics were almost the same as those of the antireflection film of the comparative example.

In addition, in the examples, an antireflection film in which two high refractive index layers of ZrO ₂ and low refractive index layers of SiO ₂ are laminated alternately is used as an example, but the present invention is not limited to this. ZrO ₂ as a high refractive index material
A similar effect can be obtained by using an antireflection film that uses SiO ₂ as a low refractive index substance and has a low refractive index layer of SiO ₂ as the uppermost layer.

As described above, the antireflection film of the present invention is
A film with a thickness of 1 nm to 10 nm is placed under the top layer of SiO ₂ .
By providing _three layers of Al ₂ O, the durability, especially the moisture resistance, is significantly improved without changing the anti-reflection properties, and the product is often exposed to high humidity environments in daily life, such as eyeglass lenses. It is possible to provide an optimal antireflection film for optical components.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the basic film structure of an antireflection film for an optical component. FIGS. 2 and 3 are diagrams showing typical film configurations of conventional antireflection films. FIG. 4 is a diagram showing the film structure of an antireflection film in an example of the present invention. FIG. 5 is a diagram showing the spectral reflection characteristics of the antireflection film shown in FIG. 4. 40... Spectacle lens, 41... Surface hardening layer, 4
2...First high refractive index layer, 43...First low refractive index layer, 44...Second high refractive index layer, 45...
Al ₂ O ₃ layer, 46... second low refractive index layer.

Claims (1)

[Claims] 1. A surface hardening layer made of SiO ₂ is provided on the surface of a transparent synthetic resin optical component, and a plurality of high refractive index layers made of ZrO ₂ and low refractive index layers made of SiO ₂ are laminated alternately on the surface hardened layer, and An antireflection film in which the uppermost layer is a low refractive index layer of SiO ₂ , characterized in that the uppermost low refractive index layer is formed on a thin film layer of Al ₂ O ₃ with a thickness of 1 nm to 10 nm. Anti-reflective coating.