JP2525838B2 - Transparent plate with anti-reflection film - Google Patents

Description

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

[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, a multilayer antireflection film-attached transparent plate having such a metal layer can have extremely small surface reflection due to the multilayer antireflection film attached to the surface of the transparent substrate. The reflectance of the entire transparent plate can be reduced to only about 1% due to reflection at the interface between the other surface of the transparent substrate and the metal layer, and a multilayer antireflection film-attached transparent plate having this metal layer can be obtained. Even when it was attached to a glass display such as a CRT and used, the overall luminous reflectance could only be reduced to about 0.6%.

[Means for Solving the Problem] 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 of the transparent substrate of 1.70 to 1.70, the antireflection film has 2.00 to 2.
A refractive index of 40, and 0.10 × λ ₀ /4~0.55×λ _0/4 and (the lambda ₀ the center wavelength, the same below) the first high refractive index dielectric layer optical thickness of, for 1.37 to 1.50 the refractive index, and 0.6 × λ ₀ /4~1.6
× and lambda _0/4 optical thickness first low refractive index melting collector layer, 2.00
In ～2.40, and 0.04 × λ ₀ /4~0.5×λ _0/4 and the second high refractive index dielectric layer of optical thickness of the titanium film thickness of 10～60A,
A metal layer or alloy layer of chromium, zirconium, molybdenum, nickel, nickel-chromium alloy, or stainless steel, with a refractive index of 1.37 to 1.50 and 0.9 × λ ₀
Consists of a /4~1.3×λ _0/4 optical thickness second low refractive index dielectric layers, respective layers are successively 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, titanium oxide, tantalum oxide, zirconium oxide, praseodymium titanate, hafnium oxide, zinc sulfide, tin oxide, indium oxide, and tin-doped oxide are used as the first and second high refractive index dielectric layers. Indium (eg indium oxide to tin oxide weight ratio
Any of the 95: 5 ITO) can be used.

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

[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 7 is formed on the surface of the glass plate 1. The antireflection film 7 has a refractive index of 2.40 sequentially from the glass plate 1 side.
And the optical film thickness is 28.65 nm (center wavelength λ ₀ = 504 nm, 0.2274
× λ _0/4 and titanium (TiO ₂₎ layer 2 oxidation of a refractive index of 1.46
In, a silicon oxide (SiO ₂₎ layer 3 of the optical film thickness is _{156.66nm (1.2433 × λ 0/4} ), a refractive index of 2.40, optical film thickness is 27.6
3nm and titanium oxide (TiO ₂₎ layer 4 _{(0.2193 × λ 0/4)} , thickness stainless steel layer 4 (stainless steel 72% by weight of nickel 42 Å, 16% by weight of chromium and 8 wt% of iron alloys )
And the refractive index is 1.46 and the optical film thickness is 133.89 nm (1.0626 × λ
_0/4), a silicon oxide (SiO ₂₎ layer 6 which in each layer is formed by sequentially sputtering the glass plate 1 on the surfaces of.

The glass surface side of the glass plate 1 on which the antireflection film 7 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. FIG. 2 shows the reflection characteristics of the glass plate having the antireflection film attached thereto, the transmittance characteristics of the glass plate are shown in FIG. 3, and the luminous reflectance and the luminous transmittance are shown in Table 1.

Example 2 An antireflection film-adhered glass plate having the same structure as that shown in FIG. 1, the multilayer film of the antireflection film 7 was changed as follows.

That is, the antireflection film 7 is a refractive index of 2.40, optical film thickness and a titanium oxide layer 2 of _{24.18nm (0.1919 × λ 0/4} ), a refractive index of 1.37, optical film thickness of 191.36nm (1.5187 × λ _0/4 magnesium fluoride (MgF ₂₎ layer 3), a refractive index of 2.40, optical film thickness and a titanium oxide layer 4 of 5.24 (0.0416 × lambda _0/4),
Nickel-chromium alloy (thickness 90% nickel and 10% chromium) alloy layer 5 with a film thickness of 37Å and refractive index 1.37
In optical thickness made of magnesium fluoride layer 6 which in _{122.48 (0.9721 × λ 0/4} ), 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 0.06% and the luminous transmittance was 60%. there were.

[Embodiment 3] An antireflection film-attached glass plate having the same structure as that shown in FIG.
That is, the antireflection film has a refractive index of 2.15 and an optical film thickness of 2
_{7.28 (0.2165 × λ 0/4} ) titanate praseodymium (PrTiO
₃ ) Layer 2, with a refractive index of 1.37 and an optical film thickness of 157.17 (1.247
4 and × lambda _0/4 magnesium fluoride layer 3), the refractive index 2.15
In, titanate praseodymium layer 4 of the optical film thickness of _{23.51 (0.1866 × λ 0/4} ), thickness 35A of the nickel-chromium alloy (Ni: 90 wt%, chromium: 10 wt%) and layer 5, the refractive at a rate 1.37, optical film thickness is made of magnesium fluoride layer 6 which in _{134.01 (1.0636 × λ 0/4} ), each layer is 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 0.06% and the luminous transmittance was 60%. there were.

[Effects of the Invention] As described above, when the antireflection film-attached transparent plate of the present invention is 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, The luminous reflectance can be extremely reduced to 0.1% or less.

Therefore, the screen of the CRT becomes easier to use, and the light-absorbing metal layer or alloy layer absorbs the light incident on the fluorescent surface of the CRT, thereby improving 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: first low refractive index dielectric layer 4: second high refractive index dielectric layer 5: metal layer or alloy layer 6: second Low refractive index dielectric layer, 7: antireflection film

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display area C23C 14/18 C23C 14/18 G02B 1/11 G02B 1/10 A

Claims (3)

(57) [Claims] 1. A transparent plate having an antireflection film for preventing light reflection from 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 0.10 ×
_{λ 0 /4~0.55×λ 0/4 (λ} 0 is the center wavelength, the same below) and the optical film thickness first high refractive index dielectric layers in, the refractive index of 1.37 to 1.50, and 0.6 × lambda ₀ and /4~1.6×λ _0/4 first low refractive index melting collector layer of the optical film thickness, at 2.00 to 2.40, and 0.04 × λ _0/4
A high refractive index dielectric layer ~0.5 × λ _0/4 of the optical thickness of the second,
1.37-1.50 with a metal or alloy layer of titanium, chromium, zirconium, molybdenum, nickel, nickel-chromium alloy, or stainless steel with a thickness of 10-60 Å
A refractive index of, and consists of a 0.9 × λ ₀ /4~1.3×λ _0/4 optical thickness second low refractive index dielectric layers, comprising respective layers are sequentially formed from the transparent substrate surface A transparent plate with anti-reflection coating. 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, indium oxide, and oxidation doped with tin. The antireflection film-attached transparent plate according to claim 1, which is any of indium. 3. An antireflection film-attached transparent film according to claim 1, wherein the first and second low-refractive-index dielectric layers are either magnesium fluoride or silicon oxide. Board.