JP2565538B2 - Transparent body with anti-reflection coating including metal film - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antireflection film-attached transparent plate for reducing light reflection of a transparent substrate, particularly a multilayer reflection having a light absorbing metal layer or a metal alloy layer. The present invention relates to a transparent plate having a protective film attached.

[Prior Art] Conventionally, as a multi-layer anti-reflection film-attached transparent plate having a metal layer that absorbs light, a multi-layer anti-reflection film made of only a dielectric is formed on one surface of a transparent substrate and is transmitted to the other surface. Rate is
A light-absorbing metal layer having a thickness of 30% to 80% is known from JP-A-62-58202. The multilayer antireflection film-attached transparent plate having the metal layer is intended to adjust the transmittance of the transparent substrate by lowering the reflectance of the transparent plate by the multilayer antireflection film and absorbing light by the metal layer.

[Problems to be Solved by the Invention] However, in a multilayer antireflection film-attached transparent plate having such a metal layer, the surface reflection can be extremely reduced by the multilayer antireflection film attached to the transparent substrate surface. Due to reflection at the interface between the other surface of the transparent substrate and the metal layer, the reflectance of the entire transparent plate can be reduced to only about 1%, and a multilayer antireflection film-attached transparent plate having this metal layer can be used as a CRT. Even when it is used by pasting it on a glass display such as, the overall luminous reflectance could be reduced only to about 0.6%.

[Means for Solving the Problems] The present invention has been made to solve such conventional problems, and provides an antireflection film-attached transparent plate in which the reflectance of the entire transparent plate is extremely small. It is intended for.

To this end, the invention has a refractive index of 1.40.
In a transparent plate having an antireflection film for preventing light reflection on the surface of a transparent substrate of 1.70 to 1.70, the antireflection film is 2.
A refractive index of from 00 to 2.40, and _{0.03 × λ 0 /4~0.50×λ 0/4} ( where lambda ₀ is the center wavelength, the same below) the first high refractive index dielectric layer optical thickness of, 26A～ titanium thickness of 46 Å, chromium, zirconium, molybdenum, nickel, nickel-chromium alloys, and one of the metal layer of stainless steel, or an alloy layer, a refractive index of 2.00~2.40, 0.60 × λ ₀ /4~1.30
And the second high refractive index dielectric layer of the optical thickness of λ _0/4 ×, 1.37
A refractive index of 1.50, made up of a 1.00 × λ ₀ /4~1.08×λ _0/4 of the optical thickness of the low refractive index dielectric layers, each of said layer are sequentially formed from the transparent substrate surface.

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, as the first and second high refractive index dielectric layers, titanium oxide (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), zirconium oxide (ZrO ₂ ), praseodymium titanate (PrTiO _3). ), Hafnium oxide (HfO ₂ ), zinc sulfide (ZnS), tin oxide (SnO ₂ ), indium oxide (In
₂ O ₃ ) and a mixture of indium oxide and tin oxide (IT
Any of O) can be used. As the mixture of indium oxide and tin oxide, it is preferable to use one having a weight ratio of indium oxide and tin oxide of 95: 5.

Furthermore, in the present invention, it is preferable to use either magnesium fluoride (MgF ₂ ) or silicon oxide (SiO ₂ ) as the low refractive index dielectric layer.

[Operation] In the present invention in which a metal layer or an alloy layer having light absorption is incorporated in such an antireflection film, the light incident on the transparent plate is, of course, reflected by the back surface of the transparent plate. Alternatively, since it is absorbed and attenuated by the alloy layer, the reflected light of the entire antireflection film-attached transparent plate becomes small.

Example 1 An example of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a glass plate having a refractive index of 1.51, and an antireflection film 6 was formed on the surface of the glass 1. In the antireflection film 6 are sequentially refractive index from the glass plate 1 side 2.15, optical film thickness of 1.05 × λ _0/4 and titanate praseodymium 2 (where lambda _{0 =} 504 nm, the same applies hereinafter), the film thickness is 39Å stainless Layer 3
(Stainless steel is an alloy of 72% by weight nickel, 16% by weight chromium, and 8% by weight iron), and a refractive index of 2.15.
In, titanate praseodymium 4 optical film thickness 1.06 × λ _0/4
When a refractive index of 1.37, made optical thickness from 1.06 × λ _0/4 of the magnesium fluoride layer 5 which, each layer was formed by sequentially vacuum deposition on a glass plate one side on.

The glass surface side of the glass plate 1 on which the antireflection film 6 is formed is bonded to the CRT using an adhesive having a refractive index similar to that of glass.
It was adhered to the face plate of to eliminate the reflection on the glass surface side. The reflection characteristics of the glass plate with the antireflection film at this time are shown in FIG. 2, the transmittance characteristics are shown in FIG. 3, and the luminous reflectance and the luminous transmittance are shown in Table 1.

[Example 2] An antireflection film-attached glass plate having the same structure as that shown in Fig. 1, in which the multilayer film of the antireflection film 6 was changed as follows.

That is, in the anti-reflection film 6 has a refractive index of 2.15, optical film thickness of 0.21 × λ _0/4 (where, lambda _{0 =} 504 nm, the same applies hereinafter) and titanate praseodymium layer 2 of a thickness of 46Å NiCr alloy layer 3 (nickel-chromium alloy consisting of 90 weight percent nickel and 10 percent chromium), a refractive index of 2.15, optical film thickness and 0.79 × λ _0/4 titanate praseodymium layer 4,
A refractive index of 1.37, optical film thickness is from 1.01 × λ _0/4 of the magnesium fluoride layer 5 which, these layers are formed by sequentially vacuum evaporation on the glass plate 1.

The optical characteristics of the glass plate with an antireflection film thus obtained were measured in the same manner as in Example 1. As shown in Table 1, the luminous reflectance was 0.087% and the luminous transmittance was 63%. Met.

Example 3 An antireflection film-attached glass plate having the same structure as that shown in FIG. 1, and the multilayer film of the antireflection film 6 was as follows.

That is, in the anti-reflection film 6 has a refractive index of 2.15, optical film thickness of 0.42 × λ _0/4 (where, lambda _{0 =} 504 nm, the same applies hereinafter) and titanate praseodymium layer 2 of a thickness of 26Å NiCr Alloy layer 3 (a nickel-chromium alloy consists of 90% by weight nickel and 10% by weight chromium) and a refractive index of 2.15,
Optical film thickness 1.30 × λ _0/4 titanate praseodymium layer 4
When a refractive index of 1.37, made optical thickness from 1.06 × λ _0/4 of the magnesium fluoride layer 5 which, each layer was formed by sequentially vacuum deposition on a glass plate one side on.

The optical properties of the thus-obtained glass plate with an antireflection film attached were measured in the same manner as in Example 1. As shown in Table 1, the luminous reflectance was 0.056% and the luminous transmittance was 80%. %Met.

[Effects of the Invention] As described above, the antireflection film-attached transparent plate of the present invention can be used as an antireflection plate such as a CRT by incorporating a metal layer or an alloy layer having light absorption in the antireflection film. Can reduce the luminous reflectance to 0.1% or less.

Therefore, the screen of the CRT becomes easy to see, and further, the light-absorbing metal layer or alloy layer absorbs the light incident on the fluorescent surface of the CRT to improve the contrast. Further, by grounding the metal layer or the alloy layer, it is possible to impart an antistatic function to the transparent plate.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a cross-sectional view of a transparent plate with an antireflection film, FIG. 2 is a reflection characteristic of the transparent plate with an antireflection film, and FIG. 3 is its transmittance characteristic. Is. 1: transparent plate, 2: first high refractive index dielectric layer, 3: metal layer or alloy layer, 4: second high refractive index dielectric layer 5: low refractive index dielectric layer, 6: antireflection film

Claims (3)

(57) [Claims] 1. A transparent plate having an antireflection film for preventing light reflection on the surface of a transparent substrate having a refractive index of 1.40 to 1.70, wherein the antireflection film has a refractive index of 2.00 to 2.40 and 0.03 ×
λ ₀ /4~0.50×λ _0/4 (where lambda ₀ is the center wavelength, the same below)
And a first high-refractive-index dielectric layer having an optical film thickness of 26 Å to 46 Å, and a metal layer or alloy layer of any one of titanium, chromium, zirconium, molybdenum, nickel, nickel-chromium alloy, and stainless steel. , a refractive index of 2.00 to 2.40, and 0.60 × λ ₀ /4~1.30×λ _0/4 optical thickness the second high refractive index dielectric layer, a refractive index of 1.37~1.50, 1.00 × λ ₀ /Four
Consists of a ~1.08 × λ _0/4 of the optical thickness of the low refractive index dielectric layer, anti-reflection film deposited transparencies respective layer comprises a metal layer formed are sequentially formed from the transparent substrate surface. 2. The first and second high refractive index dielectric layers are titanium oxide, tantalum oxide, zirconium oxide, praseodymium titanate, hafnium oxide, zinc sulfide, tin oxide,
An antireflection film-attached transparent plate containing the metal film according to claim 1, which is one of indium oxide and a mixture of indium oxide and tin oxide (ITO). 3. An antireflection film-attached transparent plate containing a metal film according to claim 1 or 2, wherein the low refractive index dielectric layer is either magnesium fluoride or silicon oxide. .