JPH0634802A - Conductive antireflection film - Google Patents

Abstract

PURPOSE:To facilitate the electrical connection of a surface layer to a transparent conductive layer by forming the conductive antireflection films in such a manner that the surface layer is a low-refractive index layer and that the high-refractive index layer under the surface layer is the transparent conductive layer. CONSTITUTION:The transparent conductive antireflection films 21 are formed on a substrate 11. These films consist of the alternately laminated films 25 formed the substrate 11 and the transparent conductive layer 21 (high-refractive index layer H) and the surface layer 27 (low-refractive index layer L) formed thereon. The transparent conductive layer 21 exists on the second layer from the surface (atm. side). The alternately laminated films 25 consist of two-layered films; the high-refractive index layer H/low-refractive index layer L. Any layers, say, 2 layers, 4 layers and 6 layers, may be laminated thereon (between these laminated films and the transparent conductive layer) by a combination of the high-refractive index layer H/tee low-refractive index layer L. Namely, the number of laminated layers of the alternately laminated films 25 is not limited, insofar as the surface layer 27 (uppermost layer) is formed of the low-refractive u index layer L and the lower layer thereof as the transparent conductive layer 23. The transparent conductive layer 23 in the alternately laminated films H/L as the antireflection film functions as the high-refractive index layer H.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a moderate electrical conductivity,
In addition, the present invention relates to a conductive antireflection film having an antireflection function and a grounding method thereof.

[0002]

2. Description of the Related Art In a television, a display of a computer terminal, etc., a transparent conductive film is formed on a front glass panel for the purpose of preventing malfunction due to charging and adhesion of dust. In addition, since the transparent conductive film has a large difference in refractive index from the glass substrate and the reflectance of the glass substrate is high, the transparent conductive film imparts conductivity and antireflection ability, and makes the screen easy to see.

[0003] Conventionally, as such a conductive anti-reflection film, three-layer film composed of _{MgF 2 -In 2 O 3 -Al 2} O 3 or CeF ₃ film (Katsube et al., Optics, Vol. 7, No. 6, 250-
254 (1978)), ITO / MgF ₂ / ITO / M
4-layer film of gF ₂ (Japanese Patent Laid-Open No. 61-168899),
ITO-MgF ₂ -thin film having a refractive index of 2.05 to 2.2 -M
A four-layer film made of a gF ₂ film (Japanese Patent Publication No. 4-15443) is known.

[0004]

However, a three-layer film does not provide sufficient antireflection properties, and therefore a four-layer film or more is required. In the case of a film structure of four layers or more, as described above, in the past, the transparent conductive layer ITO was conventionally provided as the lowermost layer on the substrate. According to this layer structure, the ground electrode is formed on the substrate in advance, and a part thereof is masked to form the ITO.
By forming the thin film, the ITO thin film and the ground electrode can be electrically connected.

However, in this method, masking at the time of vapor deposition of ITO is troublesome, and it is necessary to form a ground electrode in advance, so that there is a restriction in design, and the obtained glass plate with a conductive antireflection film is used for general purposes. There is no property, and the use is limited. Further, the conventional conductive antireflection film using the ITO film as the high-refractive index layer is inferior in antireflection property to the ordinary antireflection film formed of a dielectric material.

An object of the present invention is to solve the above problems and to provide a conductive antireflection film which can be easily electrically connected to a transparent conductive layer.

[0007]

The conductive antireflection film of the present invention is a conductive antireflection film in which a total of four or more high refractive index layers and low refractive index layers are laminated on a substrate. It is a low refractive index layer, and the high refractive index layer on the lower surface of the surface layer is a transparent conductive layer.

In the present invention, the transparent conductive layer is provided as the second layer from the surface, so that an electrode can be attached to the surface to easily electrically connect the transparent conductive layer and the ground electrode. Further, by forming at least one layer, preferably all layers, of the high refractive index layers other than the second transparent conductive layer from the surface, as a dielectric layer, at least equivalent to a normal antireflection film consisting of a dielectric, Good antireflection characteristics can be obtained in a wide band.

Further, in the present invention, all layers are made of oxide,
By forming the film by a thin film forming method using plasma, such as sputtering, ion beam assisted vapor deposition, and ion plating, the abrasion resistance, stain resistance and spectral stability of the film are improved.

[0010]

EXAMPLE FIG. 1 is an explanatory view showing the layer structure of a conductive antireflection film of the present invention, in which a conductive antireflection film 2 is formed on a substrate 11.
1 is formed. The conductive antireflection film 21 is formed on the substrate 1
1 and the transparent conductive layer 21 (high refractive index layer H) and the surface layer 27 formed thereon.
(Low refractive index layer L), and the transparent conductive layer 21 is located at the second layer from the surface (atmosphere side).

The alternate laminated film 25, when viewed from the substrate 11, is a two-layer film of a high refractive index layer H / low refractive index layer L. In addition, a combination of a high refractive index layer H / a low refractive index layer L (between the transparent conductive layer) and two layers, four layers, six layers, ...
Any number of layers may be stacked. As described above, in the present invention, as long as the alternate laminated film of the high refractive index layer H and the low refractive index layer L is used, and the surface layer 27 (uppermost layer) is the low refractive index layer L and the lower layer thereof is the transparent conductive layer 23, In the above, the number of layers of the alternately laminated film 25 does not matter. In the H / L alternating laminated film as the antireflection film, the transparent conductive layer 23 functions as the high refractive index layer H.

FIG. 2 is an explanatory view showing another layer structure of the conductive antireflection film 21 of the present invention, in which the alternate laminated film 25 laminated on the substrate 11 is a low refractive index layer L / high refractive index. Rate H
/ The layer structure is basically the same as that shown in FIG. 1 except that it is formed of a three-layer film of the low refractive index layer L.
Also in the case of the conductive antireflection film having the layer structure of the type shown in FIG. 2, as in the case of FIG. 1, further on the low refractive index layer L,
By combining the high refractive index layer H and the low refractive index layer L, any number of layers such as two layers, four layers, six layers, ... Can be laminated to form an alternate laminated film.

FIG. 3 is an explanatory view showing another layer structure of the conductive antireflection film 21 of the present invention, in which the alternate laminated film 25 laminated on the substrate 11 is a high refractive index layer H / low refractive index. Rate L
/ The layer structure is basically the same as that shown in FIG. 1, except that the transparent conductive layer 23 is formed of a three-layer film of the high refractive index layer H and is formed on the high refractive index layer H. . Also in the case of the conductive antireflection film having the layer structure of the type shown in FIG. 3, as in the case of FIG. 1, the low refractive index layer L and the high refractive index layer H are further formed on the high refractive index layer H. Any combination of two layers, four layers, six layers, etc. can be laminated to form an alternate laminated film.
In the H / L alternating laminated film as the antireflection film, both the transparent conductive layer 23 and the high refractive index layer H thereunder may be regarded as an equivalent film of one high refractive index layer (H). it can.

As a transparent conductive material forming the transparent conductive layer 23, ITO (Indium Tin Oxide;
Tin-doped indium oxide), ZnO doped with Al or Si, or Cd ₂ SnO ₄
A complex oxide such as tin oxide is used.

As the substance forming the low refractive index layer L, those having a refractive index of 1.35 to 1.55 are preferable, and dielectrics such as oxides of magnesium fluoride (MgF ₂ ) and silicon dioxide (SiO ₂ ) are used. The body is typical. The surface layer is made of SiO
By comprising an oxide layer such as ₂ , the following operational effects can be obtained.

The surface is smooth and stains such as fingerprints can be easily wiped off. Improves chemical resistance. Even when the film is formed by vacuum evaporation, the filling rate is high, and therefore the change in color and the change over time due to the environment are small.

The material forming the high refractive index layer H is preferably a material having a refractive index of 1.8 to 2.9, and titanium oxide (T
iO ₂ ), tantalum oxide (Ta ₂ O ₅ ), hafnium oxide (HfO ₂ ), zirconium oxide (ZrO ₂ ), TiO ₂
+ Pr ₆ O ₁₁ , ZrO ₂ + dielectric oxide such as TiO ₂ ,
Alternatively, a transparent conductive material such as ITO is used.
Particularly, by forming the lower layer of the surface layer as a transparent conductive layer and forming the remaining high-refractive index layer L of a dielectric material, it is excellent in a wide band equal to or more than a normal antireflection film in which all layers are made of a dielectric material. The anti-reflection property is obtained.

The specific film structure is such that the central wavelength peak that lowers the reflectance is determined, and the transparent conductive material, the high refractive index material and the low refractive index material to be used are selected to obtain the refractive index and the number of laminated layers. From this, the optimum film thickness of each layer can be determined.

Tables 1 to 5 (corresponding to FIGS. 4 to 8) show specific examples of the layer constitution and the spectral reflection characteristics thereof. The first layer is a layer directly formed on the substrate, and each layer is sequentially laminated below. As a substrate, BK7 (refractive index 1.51
5) was used. Table 1 The surface layer 27 was MgF _2, Table 2
It can be seen that the layer structure of (1) provides excellent antireflection characteristics in a wide band.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

The conductive antireflection film of the present invention can be formed by a general vacuum deposition method, and excellent film characteristics can be obtained.
Alternatively, all the layers may be formed of oxides and formed by a thin film forming method in a plasma atmosphere. In addition, MgF
_In the case of No. ₂ , when formed in plasma, the film is absorbed and the transmission characteristics are deteriorated. However, oxides such as SiO ₂ do not cause film absorption even when formed in plasma.

When all layers are formed in plasma, the following operational effects are further improved as compared with the ordinary vacuum deposition method.

There is no change in the spectral reflection characteristics due to the environment. Therefore, the reflected light of the film is always the same even when the use environment changes under high humidity or low humidity depending on the season. The peak of the spectral reflection characteristic changes, and the slight reflection color from the display surface observed by the human eye changes subtly like green → reddish green or green → bluish green. Then, since the human eyes are sensitive to such a subtle color change, the reliability of the quality of the conductive antireflection film is lowered, which is not preferable in terms of product quality.

It has high abrasion resistance and is not easily scratched even when wiped or rubbed. Since the surface is smooth, it can be easily wiped off even if fingerprints are attached.

As a method for forming a film in plasma, a sputtering method, an ion plating method in which a deposition material is ionized and deposited by high frequency discharge using a high frequency RF coil, and an ion beam is applied to a substrate by an ion source (gun). There is ion beam assisted vapor deposition that performs vacuum vapor deposition while irradiating.

The obtained conductive antireflection film 21 can be electrically contacted with the transparent conductive layer 23 from the film surface via the surface layer 27. Therefore, the ground can be easily grounded by attaching an electrode to the surface of the conductive antireflection film 21 with solder or the like, or by pressing an electrode terminal or the like.

[0031]

According to the present invention, four or more high refractive index layers and low refractive index layers are laminated to form an antireflection film, and the lower layer of the surface layer is used as a transparent conductive layer to impart conductivity. This makes it possible to easily make electrical contact with the transparent conductive layer simply by attaching electrodes to the surface.

Manufacturing Example A conductive antireflection film of the present invention was formed by using a magnetron sputtering apparatus equipped with three targets of ITO, TiO ₂ and SiO ₂ and a transfer mechanism for transferring a substrate between the targets. BK7 as a substrate was set in a vacuum chamber and evacuated to a high vacuum of 1 × 10 ⁻⁵ Torr or less, and then argon gas containing oxygen was introduced to adjust the sputtering pressure to 2 × 10 ⁻³ Torr.

Next, while heating the substrate, the targets were sequentially sputtered to form an eight-layer film (TiO ₂ / Si) shown in Table 5.
O ₂ / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / ITO /
A conductive antireflection film made of SiO ₂ ) was formed.

This conductive antireflection film had good abrasion resistance and was not scratched in the abrasion test, and even when fingerprints were attached, it could be wiped off with a simple blanking. Further, BK7 having a conductive antireflection film formed thereon is placed in a constant temperature and humidity chamber,
When the reflected light was visually observed under the low temperature and low humidity environment and the high temperature and high humidity environment conditions of 10 ° C.-20% RH and 35 ° C.-80% RH, no color change was observed in the reflected light between the two environments.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a layer configuration example of a conductive antireflection film of the present invention.

FIG. 2 is an explanatory diagram showing a layer configuration example of a conductive antireflection film of the present invention.

FIG. 3 is an explanatory diagram showing a layer configuration example of a conductive antireflection film of the present invention.

FIG. 4 is a graph showing the spectral reflection characteristics of the conductive antireflection film of the present invention.

FIG. 5 is a graph showing the spectral reflection characteristics of the conductive antireflection film of the present invention.

FIG. 6 is a graph showing the spectral reflection characteristics of the conductive antireflection film of the present invention.

FIG. 7 is a graph showing the spectral reflection characteristics of the conductive antireflection film of the present invention.

FIG. 8 is a graph showing the spectral reflection characteristics of the conductive antireflection film of the present invention.

[Explanation of symbols]

 11 Substrate 21 Conductive Antireflection Film 23 Transparent Conductive Layer 25 Alternate Laminated Film 27 Surface Layer L Low Refractive Index Layer H High Refractive Index Layer

Claims (4)

[Claims] 1. A conductive antireflection film having a high refractive index layer and a low refractive index layer laminated on a substrate in a total of 4 or more layers, wherein the surface layer is a low refractive index layer, and the height of the lower surface of the surface layer is high. A conductive antireflection film, wherein the refractive index layer is a transparent conductive layer. 2. The conductive antireflection film according to claim 1, wherein at least one high refractive index layer other than the high refractive index layer on the lower surface of the surface layer is made of a dielectric material. 3. The conductive antireflection film according to claim 1, wherein the low refractive index layer and the high refractive index layer are formed by a thin film forming method in a plasma atmosphere. 4. The conductive antireflection film according to claim 1, wherein a ground electrode is attached on the surface layer, and the transparent conductive layer and the ground are connected via the surface layer. A method for grounding a conductive antireflection film, which comprises electrically connecting to an electrode.