JPH01168855A - Transparent sheet coated with antireflection film containing metal film - Google Patents

Abstract

PURPOSE:To remarkably reduce the light reflectivity on the surface of a transparent glass sheet by forming an antireflection film consisting of a low-refractive-index dielectric layer, a high-refractive-index dielectric layer, a specified metal or alloy layer, a high-refractive-index dielectric layer, and a low-refractive-index dielectric layer on the transparent glass sheet. CONSTITUTION:The antireflection layer 7 consisting of the first lowrefractive-index dielectric layer 2 having 1.37-1.50 retractive index and optical film thickness fulfilling (0.30-1.10)l0/4 (l0 is the central wavelength), the first high-retractive-index dielectrid layer 3 having 2.00-2.40 refractive index and optical film thickness fulfilling (0.02-0.25)l0/4, the metal or alloy layer 4 of Ti, Cr, Zr, Ni-Cr alloy, etc., having 40-80Angstrom thickness, the second high-refractive-index dielectric layer 5 having 2.00-2.40 refractive index and optical film thickness fulfilling (0.40-0.90)l0/4, and the second low-retractive-index dielectric layer 6 having 1.37-1.50 refractive index and optical film thickness fulifilling (1.03-1.15)lambda0/4 is formed by vacuum deposition on the transparent substrate 1 such as a glass sheet having 1.40-1.70 refractive index. In this case, TiO2, PrTiO3, etc., are used for the high-refractive-index dielectric layers 3 and 5, and MgF2 or SiO2 is used for the low-refractive-index dielectric layers 2 and 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a transparent plate coated with an anti-reflection film for reducing light reflection on a transparent substrate, particularly a multilayer reflective film having a metal layer or a metal alloy layer that absorbs light. This invention relates to a transparent plate with a protective film attached.

[Prior Art] Conventionally, as a transparent plate with a multilayer antireflection coating containing a metal layer that absorbs light, a multilayer antireflection coating made only of dielectric material is formed on one side of a transparent substrate, and a multilayer antireflection coating made of only a dielectric material is formed on the other side. Transmittance is 3
A method in which a metal layer with light absorption is formed with a thickness of 0% to 80% is known from JP-A-62-58202.

This transparent plate with a multilayer antireflection coating having a metal layer is intended to lower the reflectance of the transparent plate by the multilayer antireflection coating and to adjust the transmittance of the transparent substrate by absorbing light by the metal layer.

[Problems to be Solved by the Invention] However, in the case of such a transparent plate coated with a multilayer antireflection film applied to a metal layer, the surface reflection can be made extremely small due to the multilayer antireflection film attached to the surface of the transparent substrate. However, due to reflections at the interface between the other surface of the transparent substrate and the metal layer, etc., the reflectance of the entire transparent plate can be reduced to only about 1%. Even when used by pasting it on a glass display such as a CRT, the overall visibility reflectance could only be reduced to about 0.8%.

[Means for Solving the Problems] The present invention has been made to solve these conventional problems, and it is an object of the present invention to provide a transparent plate coated with an anti-reflection film in which the reflectance of the entire transparent plate is extremely small. The purpose is to

To achieve this objective, the present invention has a refractive index of 1.4.
In a transparent plate having an antireflection film attached to the surface of a transparent substrate with a refractive index of 1.37 to 1.50, the antireflection film has a refractive index of 1.37 to 1.50, and a 0.30× λO/
4-1. a first low refractive index dielectric layer with an optical thickness of IO×λ0/4 (where λO is the center wavelength, the same applies hereinafter);
With a refractive index of ~2°40, 0.02 x λO/4 ~ 0.25
×λ0/4 first high refractive index melting material layer, 40A to 80A
A metal layer or alloy layer of any one of titanium, chromium, zirconium, molybdenum, nickel, nickel-chromium alloy, and stainless steel, and a refractive index of 2.00 to 2.40, 0.40 × λ0/4 A first high refractive index melting layer of ~0.90×λ0/4 and a first high refractive index melt layer of 1.03×λ0/4 to 1.15×λ0/4 with a refractive index of 1.37 to 1.50. 2 low refractive index dielectric layers, each layer being formed sequentially from the surface of the transparent substrate.

In the present invention, a glass plate or a synthetic resin plate is usually used as the transparent substrate having a refractive index of 1.40 to 1.70. As the synthetic resin plate, an acrylic resin plate, a polycarbonate resin plate, or a polystyrene resin plate is preferably used.

Further, in the present invention, the first and second high refractive index dielectric layers may be titanium oxide (Ti02), tantalum oxide (
Ta205), zirconium oxide (Zr02
), praseodymium titanate (PrTiO3), hafnium oxide (Hf02), zinc sulfide (2! n S )
, tin oxide (Sn02), indium oxide (In203)
), and mixtures of indium oxide and tin oxide (ITO
) can be used.

The mixture of indium oxide and tin oxide preferably has a weight ratio of indium oxide to tin oxide of 95:5.

Furthermore, in the present invention, either magnesium fluoride (MgF2) or silicon oxide (Si02) can be used as the first and second low refractive index dielectric layers.

[Function] In the present invention, in which a light-absorbing metal layer or alloy layer is incorporated into such an antireflection film, not only light incident on the transparent plate but also light reflected on the back surface of the transparent plate is absorbed by the metal layer, Alternatively, since the light is absorbed and attenuated by the alloy layer, the amount of light reflected from the entire transparent plate coated with the antireflection film becomes small.

[Example 1] Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a glass plate having a refractive index of 1.51, and an antireflection film 7 is formed on the surface of the glass plate 1. The anti-reflection film 7 has a refractive index of 1.37 from the surface of the glass plate 1, and a magnesium fluoride layer 2 with an optical thickness of 0.3388×λ0/4 (however, the same is true below λO=504 nm1), and a magnesium fluoride layer 2 with a refractive index of 1.37. 2.40, optical film thickness is 0.1842×
Titanium oxide layer 3 with a thickness of λ0/4, stainless steel with a film thickness of 68λ (72% by weight of nickel, 16% by weight of chromium,
(alloyed with 8% by weight of iron) layer 4 with a refractive index of 2.40,
Titanium oxide layer 5 with an optical thickness of 0.7355×λO/4 and a refractive index of 1.37 with an optical thickness of 1.0402×λ0
/4 magnesium fluoride layer 6, and each layer was sequentially formed on one surface of a glass plate using a vacuum evaporation method.

The glass surface side of the glass plate 1 on which the anti-reflection film 7 has been formed is attached to a CRT using an adhesive having a refractive index similar to that of the glass.
Glued to the face plate of the camera to eliminate reflections on the glass side. The reflection characteristics of the glass plate to which the antireflection film was attached are shown in FIG. 2, the transmittance characteristics are shown in FIG. 3, and the luminous reflectance and luminous transmittance are shown in Table 1, respectively.

Table 1 Note that in the conventional example, only a luminous reflectance of 0.65% and a luminous transmittance of 80% were obtained.

[Example 2] A glass plate having an antireflection film attached thereto had the same structure as shown in FIG. 1, and the following multilayer film was used as the antireflection film 7.

That is, the antireflection film 7 has a silicon oxide layer 2 with a refractive index of 1.46 and an optical thickness of 0.4045×λO/4, and a silicon oxide layer 2 with a refractive index of 2.40 and an optical thickness of 0°1729×λ0. /4
a titanium oxide layer 3 with a thickness of 57A, a nickel-chromium alloy (90% by weight nickel and 10% by weight chromium alloy) layer 4, a refractive index of 2.40, and an optical thickness of 0.725.
It consists of a titanium oxide layer 5 with a thickness of 1×λ0/4 and a silicon oxide layer 6 with a refractive index of 1.46 and an optical thickness of 1.0451×λ0/4, and these layers are sequentially placed on the glass plate 1. Formed by sputtering method.

The optical properties of the thus obtained anti-reflection coated glass plate were measured in the same manner as in Example 1.As shown in Table 1, the luminous reflectance was 0.12%, and the luminous transmittance was 0.12%. It was 55%.

[Example 3] A glass plate with an antireflection film attached has the same structure as shown in FIG. 1, and the following multilayer film was used as the antireflection M7.

That is, the anti-reflection film 7 is a magnesium fluoride layer 2 with a refractive index of 1.37 and an optical thickness of 0.4153×λO/4.
, the refractive index is 2.15, and the optical film thickness is 0.2031×λ
A praseodymium titanate layer of O/4, a stainless alloy (alloy of 72 wt% nickel, 16 wt% chromium, and 8 wt% iron) layer 4 with a film thickness of 49A, and a refractive index of 1.
37 and a magnesium fluoride layer 6 having an optical thickness of 1.0284×λO/4, and these layers were sequentially formed on a glass plate by vacuum evaporation.

The optical properties of the thus obtained anti-reflection coated glass plate were measured in the same manner as in Example 1, and as shown in Table 1, the luminous reflectance was 0°07%, and the luminous transmittance was 0.07%. was 60%.

[Effects of the Invention] As described above, the transparent plate coated with an antireflection film of the present invention can be used as an antireflection plate for CRTs, etc. by incorporating a light-absorbing metal layer or alloy layer into the antireflection film. Visibility reflectance can be made extremely small.

Therefore, the screen of the CRT becomes easier to see, and the light incident on the phosphor screen of the CRT is absorbed by the light-absorbing metal layer or metal alloy, resulting in improved film stability. Further, by grounding the metal layer or the alloy layer, an antistatic function can be imparted to the transparent plate.

[Brief explanation of the drawing]

The drawings show examples of the present invention, in which Fig. 1 is a cross-sectional view of a transparent plate coated with an anti-reflection film, Fig. 2 shows the reflection characteristics of the transparent plate coated with the anti-reflection film, and Fig. 3 shows its transmittance characteristics. It is. 1: Transparent plate, 2: First low refractive index dielectric layer, 3: First high refractive index fusion layer 4: Metal layer or alloy layer 5: Second low refractive index dielectric layer 6: First 2: high refractive index melting material layer, 7: antireflection film first factor

Claims (3)

[Claims] (1) A transparent plate having an antireflection film attached to the surface of a transparent substrate having a refractive index of 1.40 to 1.70 to prevent reflection of light, the antireflection film having a refractive index of 1.37 to 1.50. a first low refractive index dielectric layer with an optical thickness of 0.30 x λ_0/4 to 1.10 x λ_0/4 (where λ_0 is the center wavelength, the same applies hereinafter) in terms of refractive index; With a refractive index of .40, 0
．． 02×λ_0/4 to 0.25×λ_0/4 first high refractive index melting layer, 40 Å to 80 Å titanium, chromium,
A metal layer or alloy layer of any one of zirconium, molybdenum, nickel, nickel chromium alloy, and stainless steel, and a refractive index of 2.00 to 2.40, 0.40×λ
A first high refractive index dielectric layer of _0/4 to 0.90×λ_0/4 and a refractive index of 1.37 to 1.50, 1.03×λ
A second low refractive index dielectric layer of _0/4 to 1.15×λ_0/4, and each layer includes a metal film formed sequentially from the surface of the transparent substrate. (2) The first and second high refractive index dielectric layers are made of titanium oxide, tantalum oxide, zirconium oxide, praseodymium titanate, hafnium oxide, zinc sulfide, tin oxide, indium oxide, and combinations of indium oxide and tin oxide. blend(
An anti-reflection film-attached transparent plate comprising the metal film according to claim 1, which is any one of ITO and ITO. (3) An antireflection film containing a metal film according to claim 1 or 2, wherein the first and second low refractive index dielectric layers are either magnesium fluoride or silicon oxide. Adhesive transparent plate.