JPH03196101A - Antireflection film - Google Patents

Abstract

PURPOSE:To prevent ghosts and flares when this antireflection film is applied on a glass lens by forming the antireflection film into the 7-layered constitution provided on a glass substrate having from 1.5 to 1.8 refractive index, forming this constitution of the 1st layer and the 2nd layers, successively counted from the substrate, in such a manner as to satisfy specific conditions and further forming the 6th layer of a mixture contg. ZrO2 and TiO2. CONSTITUTION:The antireflection film has the 7-layered constitution provided on the glass substrate having from 1.5 to 1.8 refractive index and is constituted to satisfy the conditions expressed by equations I to VII when the layers are designated as the 1st layer and the 2nd layer successively counted from the substrate. Further, the 6th layer is formed of the mixture composed of the ZrO2 and TiO2. If the equations I to VII, lambda0 denotes the design wavelength selected in a 450 to 550nm range; ni denotes a refractive index; nidi denotes an optical film thickness; (i) denotes an integer from 1 to 7. The surface reflectivity in the wavelength range of a visible ray region is lowered in this way when the antireflection film is provided on the glass lens. An excellent antireflection effect is thus obtd. The ghosts and flares are eliminated and the lens is particularly adequately usable as a spectacle lens.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to an antireflection film coated on optical glass.

[Prior Art] Conventionally, it is well known to provide an antireflection film on an optical glass substrate in order to improve the reflection characteristics of the surface of the optical glass. As such an antireflection film, for example, U.S. Patent No. 3,185.020 discloses that the first layer has a thickness of λ/4, the second layer has a thickness of λ/2, and
A three-layer antireflection film is disclosed in which the 311th layer is λ/4 (λ is the reference wavelength of the antireflection wavelength range).

However, when the antireflection coating disclosed in the above-mentioned US patent publication is applied to a glass lens, the entire visible wavelength range (3
80 to 780n+s) is insufficient, and when used as an eyeglass lens, there is a problem in that reflection flickering such as a ghost phenomenon or a flare phenomenon is perceived. In order to solve the above problem, for example, Japanese Patent Publication No. 57-25801 discloses a seven-layer antireflection film.
Furthermore, Japanese Patent Publication No. 8801/1983 discloses a multilayer antireflection film having four or more layers.

[Problems to be Solved by the Invention] However, the antireflection films disclosed in Japanese Patent Publication No. 57-25801 and Japanese Patent Publication No. 64-8801,
A non-uniform film, such as TiO2, which has a property of having a refractive index different in the thickness direction, is formed. Since the refractive index of the unconstrained M film largely depends on the degree of vacuum, there is a problem in that it is difficult to obtain desired reflection characteristics with good reproducibility.

Therefore, the object of the present invention is to have an excellent antireflection effect in the wavelength range of visible light, to prevent ghosting and flare phenomena from occurring even when applied to a glass lens, and to be able to obtain desired reflection characteristics with good reproducibility. An object of the present invention is to provide an antireflection film.

[Means for Solving the Problems J] As a result of intensive research to achieve the above-mentioned object, the present invention is based on a seven-layer structure provided on a glass substrate having a refractive index of approximately 1.5 to 1.8. An anti-reflection film, which satisfies the following conditions when the first layer and the second layer are counted from the base material, and the sixth layer is made of a mixture containing ZrO2 and TiO2. They discovered a membrane and led to the present invention.

1st layer 1.38 ≦ ni ≦1.390.07λ
0 ≦ni dl ≦0.14λ0 2nd layer 1.
62 ≦ 02 ≦2.050.02λ0 ≦n2
d2 ≦0.07λ0 311th ns ≧1
．． 90 0.06λ0 ≦n3 d3 ≦0.10λ0 4th
1!1 1.38 ≦ n4 ≦1.390, 10
λ0 ≦n4 d4 ≦0.13λ0fR5FII
ns ≧1,900.05λ0 ≦
n5 d5 ≦0.10λ0 6th layer 2.05
≦06 ≦2.150.48λ0 ≦n6 d6
≦0.52λ0 7th layer 1.38≦07≦1
．． 390, 23λ0 ≦n7 d7 ≦O627λ
0, where λ0 is a design wavelength selected in the range of 450 to 550 nrn, ni is the refractive index, n1di is the optical thickness, and 1 is an integer from 1 to 7.

The present invention will be explained in detail below.

It is essential that the sixth layer of the antireflection film of the present invention is composed of a mixed thermal layer containing ZrO2 and TlO2. The reason for this is that by mixing ZrO2 with TiOz, it is possible to adjust the heterogeneity of a heterogeneous film that has a property that the refractive index differs in the thickness direction, and it also shows no absorption and no refraction. This is because it has a high refractive index of 2.05 to 2.15. The molar composition ratio of ZrO2 and TiO2 is 1 for ZrO2 and 0.0 for TiO2.
15 to 0.20 is preferably used.

The film material for each layer of the antireflection film of the present invention is not particularly limited as long as it satisfies the range of refractive index and optical thickness of each layer, but the first, fourth, and seventh layers are A material with a refractive index, for example, a refractive index of 1.38 to 1°3977) MgF2, the second layer is A I 203 *G1ZrO2, the third layer,
The fifth layer is preferably composed of ZrO2 or a mixture of ZrO2 and TiO2. The reason is that it exhibits no absorption and can provide a desired refractive index and strong film strength.

Incidentally, the refractive index of the glass substrate used in the present invention is in the range of 1.5 to 1.8. The reason is that if the refractive index of the glass substrate is in the range of 1.5 to 1.8, the vapor deposition material of each layer of the antireflection film of the present invention and the lamination order of the vapor deposition material can be applied to the glass substrate without changing the layering order. This is because it can be applied.

In the present invention, the first to seventh layers can be provided by vacuum deposition or sputtering. Vacuum deposition is more preferred. Methods such as ion beam assist may also be applied as appropriate.

[Example 1] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

FIG. 1 is a sectional view showing an antireflection film according to the present invention. In Figure 1, anti-reflection RQ CG, t I plate A
From the side to the air B side, the 1111th, 21st FIJ2,
It consists of 3rd layer 3, 4th layer 14, 5115th layer, 6116th layer, and 7th layer 7 configuration.

Next, the specific structures of Examples 1 to 4 of the present invention are shown in Table 1, the specific structures of Examples 5 to 8 are shown in Table 2, the specific structures of Examples 9 to 12 are shown in Table 3, and The spectral reflectance curves of Examples 1 to 3 are shown in Figure 2, and the spectral reflectance curves of Examples 5 to 7 are shown in Figure 3.
The spectral reflectance curves of Examples 9 to 11 are shown in FIG. 4, and the spectral reflectance curve of Example 4.8°12 is shown in FIG. However, in Tables 1 to 3, the optical thickness of each layer is based on the design wavelength λ.
This value is calculated assuming that 0 is 500 nm.

Incidentally, the vapor deposition method was performed using a vacuum vapor deposition method under conditions of a substrate temperature of 300° C. and a degree of vacuum of 3×10 −5 Torr. LHI-■ (Hoya) is a glass lens with a refractive index of 1.6.
LHI (manufactured by Co., Ltd.), as a glass lens with a refractive index of 1.7
7rO2 and THI-II (manufactured by Hoya Co., Ltd.) was used as a glass lens with a refractive index of 1°8.
The molar composition ratio with iO2 is 1 for ZrO2 and 1 for TlO2.
2 went 0.18F. As is clear from FIGS. 2 to 5, in all Examples, the luminous reflectance on one side was approximately 0.15% or less, and had extremely excellent antireflection properties.

In addition, Figure 6 shows the reflectance as a function of the deposition time (film thickness change) of the sixth layer when the sixth layer of 0.50λO was repeatedly formed five times using monochromatic photometry (λO = 550nm). It is a figure showing a change. As shown in FIG. 6, the reflectance values at the deposition start point a and the minimum extreme value point of 0.50λO are almost the same in all cases, and the ZrO2 and 1-
The film made of i02 was homogeneous.

Furthermore, when glass lenses coated with anti-reflection films shown in Examples 1 to 12 were repeatedly produced, it was possible to obtain good reproducibility of reflection characteristics with single-sided luminous reflectance of approximately 0.15% or less for all glass lenses. did it.

(The following is a blank space) [Effects of the Invention] As described in detail above, when the antireflection film of the present invention is provided on a glass lens, the wavelength W! Since the surface reflectance is extremely low in the surrounding area and has an excellent antireflection effect, ghost phenomena and flare phenomena are eliminated, and it can be particularly suitably used as a wIIlt lens. Furthermore, since a material that can solve the problem of non-uniformity is used in the sixth layer, reflection characteristics can be obtained with good reproducibility.

Furthermore, the antireflection film of the present invention has a refractive index of 1.5 to 1.8.
It has become possible to obtain almost the same reflection characteristics in glass lenses without changing the layering order of the vapor-deposited materials.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of the antireflection film according to the present invention, FIG. 2 is a spectral reflectance curve diagram of Examples 1 to 3, and FIG. 3 is a spectral reflectance curve of Examples 5 to 7. 4 is a spectral reflectance curve diagram of Examples 9 to 11, FIG. 5 is a spectral reflectance curve diagram of Examples 4, 8.12, and FIG. 6 is a spectral reflectance curve diagram of Examples 9-11.
! It is a reflectance change diagram of the 6th layer controlled by 11-color photometry. A° Glass substrate, B: Air C: Antireflection film 1: First layer, 2: Second layer 3: Third layer, 4: Fourth layer 5゛ 5.6: Sixth layer 7° 7th layer

Claims (4)

[Claims] (1) It is an antireflection film with a seven-layer structure provided on a glass substrate with a refractive index of approximately 1.5 to 1.8, and when the first and second layers are counted from the base material, the following is shown. An antireflection film that satisfies the following conditions and further comprises a sixth layer made of a mixture containing ZrO_2 and TiO_2; first layer 1.38≦n_1≦1.39 0.07λ_0≦n_1d_1≦0.14λ_0 2nd layer 1.62≦n_2≦2.05 0.02λ_0≦n_2d_2≦0.07λ_0 3rd layer n_3≧1.90 0.06λ_0≦n_3d_3≦0.10λ_0 4th layer 1.38≦n_4≦1.39 0.10λ_0≦n_4d_4≦0.13λ_0 5th layer n_5≧1.90 0.05λ_0≦n_5d_5≦0.10λ_0 6th layer 2.05≦n_6≦2.15 0.48λ_0≦n_6d_6≦0.52λ_0 7th layer 1.38≦n_7≦1.39 0.23λ_0≦n_7d_7≦0.27λ_0However,
λ_0 is a design wavelength selected in the range of 450 to 550 nm, ni is a refractive index, nidi is an optical film thickness, and i is an integer of 1 to 7. (2) The antireflection film according to claim 1, wherein the first layer, the fourth layer, and the seventh layer are made of MgF_2. (3) The antireflection film according to claim 1 or 2, wherein the second layer is made of Al_2O_3 or ZrO_2. (4) The antireflection film according to claim 1, 2, or 3, wherein the third layer and the fifth layer are made of ZrO_2 or a mixture of ZrO_2 and TiO_2.