JP2001318203A - Electrically conductive antireflection film and glass panel for cathode-ray tube coated with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrically conductive antireflection film, capable of attaining reduction of reflected light and the enhancement of contrast, having superior antistatic performance and electromagnetic wave shielding capability, superior heat resistance and less liable to peel from a substrate and to provide a glass panel for a cathode-ray tube having the antireflection film formed on the outer surface of the face part. SOLUTION: The electrically conductive antireflection film includes four layers formed on a substrate, namely a transparent layer whose refractive index is 1.4-2.3 and geometrical thickness is 0.5-250 nm as a first layer, a second layer based on a transition metal carbonitride or a transition metal oxycarbonitride, and a transparent layer whose refractive index is 1.4-2.3 and geometrical thickness is 0.5-100 nm as a third layer in this order from the substrate side and further has a transparent layer whose refractive index is 1.4-1.6 and geometrical thickness is 50-140 nm as an outer layer on the outside of the third layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a conductive anti-reflection film,
The present invention relates to a glass panel for a cathode ray tube in which the conductive antireflection film is formed to cover the outer surface of the face portion.

[0002]

2. Description of the Related Art Conventionally, cathode ray tubes have been required to reduce reflected light and improve contrast. Recently, it has also been required to prevent electrification and shield electromagnetic waves that have a bad effect on the human body. It is becoming.

[0003] Therefore, by forming a conductive anti-reflection film on the outer surface of the face of the glass panel, which is the image display surface of the cathode ray tube, the reflected light is reduced, the contrast is improved, and the antistatic and electromagnetic wave shielding are further prevented. It has been proposed to add the function of.

For example, Japanese Patent Publication No. 6-510382 proposes a conductive anti-reflection film composed of a layer containing NbN, a layer containing TiO _2, and a layer containing SiO ₂ in order from the substrate side.

Japanese Patent Application Laid-Open No. 9-156964 discloses that
In order from the substrate side, a conductive antireflection film comprising a layer mainly composed of a metal nitride selected from Ti, Zr and Hf, a layer mainly composed of Si or Si nitride, and a SiO ₂ layer is proposed. Have been.

[0006]

By the way, when producing a cathode ray tube, after forming various functional films on a glass panel as a base, the funnel is frit-sealed.
The inside is further evacuated. In these sealing and evacuation steps, a heat treatment at 400 ° C. or higher is performed.

However, the conductive anti-reflection film disclosed in Japanese Patent Application Laid-Open No. 6-510382 and Japanese Patent Application Laid-Open No. 9-156964 greatly reduces the reflected light on the outer surface of the face portion, and further causes coloring. With the layer, the contrast of the cathode ray tube can be improved, but the heat resistance is insufficient, and the reflectance and the resistance value are easily increased by heat treatment, and the expected reflectance and the electromagnetic wave shielding ability are improved. Hard to obtain,
Further, since the adhesion strength between the film and the substrate is low, film peeling is likely to occur.

It is an object of the present invention to reduce reflected light and improve contrast, to have excellent antistatic properties and electromagnetic wave shielding ability, to have excellent heat resistance, and to cause film peeling from a substrate. An object of the present invention is to provide a conductive anti-reflection film which is difficult to be provided, and a glass panel for a cathode ray tube in which the conductive anti-reflection film is formed to cover the outer surface of the face portion.

[0009]

SUMMARY OF THE INVENTION A first conductive anti-reflective coating according to the present invention includes four layers formed on a substrate,
In order from the substrate side, a transparent layer having a refractive index of 1.4 to 2.3,
A first layer having a geometric thickness of 0.5 to 250 nm,
A second layer mainly composed of a transition metal carbonitride or a transition metal carbonitride oxide, a transparent layer having a refractive index of 1.4 to 2.3 and a geometric thickness of 0.5 to 100 nm; And a refractive index of 1. outside the third layer.
It is characterized by comprising an outer layer having a geometrical thickness of 50 to 140 nm, which is a transparent layer of 4 to 1.6.

The second conductive antireflection film according to the present invention includes five layers formed on a substrate, and is a transparent layer having a refractive index of 1.4 to 2.3 in order from the substrate side. 0.5-2
A first layer having a geometric thickness of 50 nm, a second layer containing any one of transition metal carbonitride and transition metal carbonitride, and a transparent layer having a refractive index of 1.4 to 2.3. In layers,
A third layer having a geometric thickness of 0.5-100 nm;
A fourth layer mainly composed of any one of transition metal nitride, transition metal carbonitride and transition metal carbonitride oxide is provided, and a refractive index of 1.4 to 1. 6. The transparent layer according to item 6, comprising an outer layer having a geometric thickness of 50 to 140 nm.

Further, the third conductive anti-reflection film according to the present invention includes six layers formed on the substrate, and is a transparent layer having a refractive index of 1.4 to 2.3 in order from the substrate side. 0.5-2
A first layer having a geometric thickness of 50 nm, a second layer containing any one of transition metal carbonitride and transition metal carbonitride, and a transparent layer having a refractive index of 1.4 to 2.3. In layers,
A third layer having a geometric thickness of 0.5-100 nm;
A fourth layer containing any one of transition metal nitride, transition metal carbonitride and transition metal carbonitride as a main component, a transparent layer having a refractive index of 1.4 to 3.0, and 0.5 to 40 nm; And a transparent layer having a refractive index of 1.4 to 1.6 and a refractive index of 50 to 140 outside the fifth layer.
It has an outer layer having a geometric thickness of nm.

Further, the glass panel for a cathode ray tube of the present invention comprises:
The conductive antireflection film including the five layers or the six layers described above is formed on the outer surface of the face portion so that the average radius of curvature of the outer surface of the face portion is 10,000 mm or more in all radial directions passing through the center of the face portion. Yes, wall thickness 10.1
The glass is characterized by having a light transmittance of 70% or more at a wavelength of 550 nm when converted to 6 mm.

[0013]

The conductive antireflection film of the present invention will be described below in detail.

First, the first conductive anti-reflection film according to the present invention will be described. The first conductive antireflection film is formed by four layers.

The first layer formed closest to the substrate is a transparent layer having a refractive index of 1.4 to 2.3 and a refractive index of 0.5 to 250 nm.
(Preferably 0.5 to 100 nm) and has an effect of reducing surface reflected light by an interference effect with other layers. The material of the first layer is SiO ₂ , Si ₃ N ₄ ,
One selected from the group consisting of SiON, Si ₂ ON ₂ , Al ₂ O ₃ and AlON is suitable. Further, when the first layer made of such a film material is formed directly on the substrate, there is an advantage that the adhesion strength between the film and the substrate is improved and the film is hardly peeled off.

The second layer is a colored conductive layer containing a transition metal carbonitride or a transition metal carbonitride oxide as a main component, has conductivity, and has an interference effect with other layers. It has the effect of reducing the surface reflection light and widening the low reflection region in the visible light region. Further, it has an effect of suppressing an increase in resistance value after heat treatment at 400 ° C. or more and improving contrast as a light absorbing film. As the second layer, a film mainly containing one of a transition metal carbonitride and a carbonitride oxide selected from Ti, Zr, Hf, and Nb is suitable. It is preferable to use a film containing any one of carbon nitride and carbonitride oxide because the low-reflection region in the visible light region is widened.

Further, the third layer has a refractive index of 1.4 to 2.
3 to 0.5 to 100 nm (preferably 10 to 100 nm).
100 nm), and has the effect of reducing surface reflected light due to the effect of interference with other layers. The material of the third layer is made of SiO ₂ , Si ₃ N ₄ , SiON, Si ₂ O in consideration of film forming property, production cost and the like.
One selected from the group consisting of N ₂ , Al ₂ O ₃ and AlON is suitable. In particular, as a material of the first layer and the third layer, Si
With ₃ N _4, preferable since excellent heat resistance can be obtained.

The outer layer is a transparent layer having a refractive index of 1.4 to 1.6 and has a geometric thickness of 50 to 140 nm, and reduces surface reflected light by an interference effect with other layers. Has an action. This outer layer is preferably a SiO ₂ layer in consideration of film forming properties and production costs.

Meanwhile, the light transmittance of the glass panel for a cathode ray tube affects the brightness and contrast when an image is projected on the cathode ray tube. That is, the higher the light transmittance of the glass panel for a cathode ray tube, the higher the brightness, but the lower the contrast, and conversely, the lower the light transmittance of the glass panel, the higher the contrast, but the lower the brightness.

In recent years, the outer surface of the face portion of the glass panel for a cathode ray tube has been flattened. However, the flatter the outer surface of the face portion is, the more the face portion is required to obtain a desired mechanical strength. Is designed such that the radius of curvature of the inner surface is small, and the thickness of the peripheral portion is much larger than the thickness of the central portion of the face portion.

Therefore, when such a flat glass panel is made of glass having a low light transmittance, the difference in the amount of light transmission due to the difference in thickness between the central part and the peripheral part of the face part becomes large, and the central part and the peripheral part become large. This causes a luminance difference in the video of the part. Therefore, by making the glass panel from a glass with high light transmittance, it is possible to prevent the luminance of the peripheral part from being extremely lowered compared to the central part of the face part, and to form a colored film on the outer surface of the face part. Attempts have been made to improve contrast by coating.

However, the above-mentioned Japanese Patent Application Laid-Open No. Hei 6-510 has been disclosed.
The conductive anti-reflection film disclosed in Japanese Patent Publication No. 382 and Japanese Patent Application Laid-Open No. 9-156964 also has a problem that the effect of reducing the reflected light on the back surface of the face portion is small. Since the backside reflectance of a glass having a higher light transmittance is higher, the conventional conductive antireflection film as described above is coated on the outer surface of the face portion of a flat glass panel made of a glass having a higher light transmittance. Even if it is formed, it is not possible to reduce the back surface reflectance, and it is likely to cause a fatal defect that the image projected on the cathode ray tube appears double.

Therefore, in the present invention, as the second conductive antireflection film, any one of transition metal nitride, transition metal carbonitride and transition metal carbonitride is provided between the third layer and the outer layer. Was formed as the main layer. By adding this layer, the front surface reflected light and the back surface reflected light are reduced by the interference effect with other layers, and the increase in the reflectance and the resistance after the heat treatment at 400 ° C. or more is easily suppressed. Further, this layer has a function of widening a low reflection region in a visible light region, and also has a function of improving contrast as a light absorbing film. As this fourth layer,
A film containing any one of nitride, carbonitride and carbonitride oxide of a transition metal selected from Ti, Zr, Hf and Nb can be used. In particular, nitride, carbonitride and carbonitride of Ti It is preferable to use a film containing any of oxides as a main component, because a low-reflection region in a visible light region is widened.

Furthermore, in the present invention, a transparent layer having a refractive index of 1.4 to 3.0 and a refractive index of 0.5 to 3.0 is provided between the above-mentioned fourth layer as the third conductive antireflection film and the outer layer. A layer (fifth layer) having a geometric thickness of 40 nm was formed. By adding this layer, an increase in resistance value after heat treatment at 400 ° C. or higher can be easily suppressed. This fifth layer
Considering film forming properties, production costs, etc., Si ₃ N ₄ , Al
N, SiON, AlON, TiO, Ti ₂ O ₃ , Ti
O ₂ , Ta ₂ O ₅ , CeO ₂ , ZnO, Nb ₂ O ₅ , Nd
It is preferably a layer made of one selected from the group consisting of ₂ O ₃ , Sb ₂ O ₃ , HfO ₂ , In ₂ O ₃ and SnO ₂ . In particular, the nitride layer of Si ₃ N ₄ or AlN serves as a barrier layer for oxygen in the air, so that the oxidation of the TiN layer during the heat treatment is completely prevented, and the increase in the resistance value of the film after the heat treatment is reduced. This is preferable because it can be further reduced.

The geometric thickness in the present invention is λ
/ 4, etc., which means a thickness independent of wavelength. Further, in the present invention, in addition to the above-mentioned respective film layers, an additional thin film layer may be appropriately provided for the purpose of further improving the adhesion of the film or adjusting the color tone.

As a method for forming the conductive antireflection film of the present invention, a general thin film forming means can be used. For example, a sputtering method, a vacuum evaporation method, a CVD method, a spin coating method, a sol-gel method, or the like can be applied, but the sputtering method is most preferable in consideration of easy area enlargement and easy control of the film thickness.

Next, the glass panel for a cathode ray tube according to the present invention will be described.

The glass panel for a cathode ray tube according to the present invention is of a so-called flat panel type in which the average radius of curvature of the outer surface of the face portion is limited to 10,000 mm or more in all radial directions passing through the center of the face portion. In view of the above, the radius of curvature of the inner surface is reduced, and the outer surface is coated with the above-described second and third conductive antireflection films according to the present invention.

On the other hand, when the value of the average radius of curvature of the outer surface is 100
In a glass panel of less than 00 mm, the outer surface of the face portion is slightly curved, and the radius of curvature of the inner surface can be increased, so that the above-described second and third conductive antireflection films are unnecessary. That is, since such a glass panel for a cathode ray tube can reduce the thickness difference between the central portion and the peripheral portion of the face portion, it is necessary to use a glass having a high light transmittance, that is, a glass which is likely to cause backside reflection. Because there is no.

Further, the glass panel for a cathode ray tube according to the present invention has a wavelength of 5 when converted to a thickness of 10.16 mm.
The light transmittance of the glass at 50 nm is limited to 70% or more. The reason is that when the flat panel glass as described above is manufactured from glass having a light transmittance of less than 70%, a difference in luminance occurs between the center portion and the peripheral portion of the face portion, and this is avoided.

[0031]

The present invention will be described below in detail based on examples and comparative examples.

Tables 1 to 5 show the conductive anti-reflection coatings of the examples (Sample Nos. 1 to 13) and the conductive anti-reflection coatings of Comparative Examples (Sample No. 14). In each table, the film configuration of each sample, the surface reflectance before and after the heat treatment, and the resistance value are shown. Tables 2 to 5 also show the back surface reflectance of each sample after the heat treatment.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

[Table 5]

Each of the conductive antireflection films shown in Tables 1 to 5 was prepared as follows.

First, as shown in FIG. 1, the minimum value of the average radius of curvature of the outer surface of the face portion (in all radial directions passing through the center of the face portion) is 50,000 mm, and the thickness is 10.
A glass panel (17-inch size) 10 for a cathode ray tube made of glass having a light transmittance of 80% at a wavelength of 550 nm when converted to 16 mm was prepared, and the outer surface of the face portion was coated on each surface using a magnetron sputter coater. Conductive antireflection film 1 having a three-layer or six-layer structure as shown in FIG.
1 was formed. In the column of the film configuration in the table, the material of each film layer and the geometric thickness are shown.

Each sample thus obtained was placed in a box-type electric furnace, and heat-treated at 450 ° C. for 60 minutes. The surface reflectance and resistance before and after the heat treatment, and the back surface reflectance after the heat treatment were measured. The strength was determined.

As a result, in Example No. Each sample of Nos. 1 to 13 is No. 1 as a comparative example. The surface reflectance and the resistance at wavelengths of 550 nm and 620 nm after the heat treatment were significantly lower than those of the sample No. 14, and the adhesion strength between the film and the glass panel was excellent. Moreover, in the example No.
Since each of the samples Nos. 3 to 13 also has a low back surface reflectance, it is presumed that if these are used for a glass panel for a cathode ray tube, an image will not be seen as double. In addition, since each sample has a colored layer, it can be understood that high contrast can be obtained.

The surface reflectance in each table is obtained by measuring 15 ° regular reflection using an instantaneous multi-reflectometer.

The resistance value is obtained by attaching an electrode to the center of the face portion of the glass panel on the short side with an ultrasonic solder and measuring the resistance between the electrodes with a tester.

Further, the back surface reflectivity was determined by using an instantaneous multi-reflectance measuring device in consideration of the reflectivity and the absorptivity of the glass.

The adhesion strength was determined by performing a scratch resistance test with an eraser (9.8 N load, 200 reciprocations). When no peeling was observed after the test, ○ was observed. When it was done, it was represented by x.

[0046]

As described above, the conductive anti-reflection film of the present invention has excellent ability for reducing reflected light, improving contrast, preventing static electricity and shielding electromagnetic waves, and has excellent heat resistance.
Since the surface reflectance and the resistance after the heat treatment at 400 ° C. or more are low, it is suitable as a conductive anti-reflection film formed on a panel of a cathode ray tube.

The conductive antireflection film can be applied to various display substrates such as a liquid crystal display substrate and a plasma display substrate, which are subjected to a high-temperature heat treatment after film formation, in addition to the cathode ray tube.

Further, even if the conductive anti-reflection film of the present invention including five or six layers is coated on the outer surface of the face portion of the glass panel for a cathode ray tube having high light transmittance, the back surface reflectance is low. Since the image of the cathode ray tube can be prevented from being seen double, it is suitable as a conductive antireflection film formed on a glass panel for a cathode ray tube having a flat outer surface of a face portion.

Further, the glass panel for a cathode ray tube according to the present invention is a flat panel in which the average radius of curvature of the outer surface of the face portion in all radial directions passing through the center of the face portion is 10,000 mm or more, but the thickness is converted to 10.16 mm. It is formed of glass having a light transmittance of 70% or more at a wavelength of 550 nm in the case of the above. Therefore, in this glass panel, the difference in luminance between the central portion and the peripheral portion of the face portion is small.
Moreover, since the conductive antireflection film including the above five or six layers is formed on the outer surface of the face part,
Since the front surface reflectance is low, the contrast is high, the antistatic property and the electromagnetic wave shielding property are excellent, and the back surface reflectance is low, it is possible to obtain a cathode ray tube in which an image does not appear double.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a glass panel for a cathode ray tube.

[Explanation of symbols]

 10 Glass panel for cathode ray tube 11 Conductive anti-reflective coating

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/00 309 H01J 29/88 313 G02B 1/10 A H01J 29/88 Z F-term (Reference) 2K009 AA06 AA07 AA08 AA09 BB02 CC02 DD03 DD04 EE03 4F100 AA12C AA12D AA19 AA20 AA32 AG00A AR00B AR00D AR00E AT00A BA05 BA07 BA10A BA10E BA13 EH66 GB48 JD08 JG01 JG03 JJ03 JN01B JN01D JN01E JN06 JN18B JN18D JN18E YY00 YY00B YY00D YY00E 4G059 AA07 AB11 AC04 AC12 GA02 GA12 5C032 AA02 DD02 DE01 DE03 DG01 DG02 5G435 AA02 AA09 AA11 AA12 AA16 BB02 BB06 BB12 EE03 FF01 GG11 GG32 GG33 HH03 HH05 HH12 KK07

Claims (4)

[Claims] 1. A transparent layer comprising four layers formed on a substrate and having a refractive index of 1.4 to 2.3 in order from the substrate side.
A first layer having a geometric thickness of 0.5 to 250 nm,
A second layer mainly composed of a transition metal carbonitride or a transition metal carbonitride oxide, a transparent layer having a refractive index of 1.4 to 2.3 and a geometric thickness of 0.5 to 100 nm; And a refractive index of 1. outside the third layer.
A conductive anti-reflection film comprising a transparent layer having a thickness of 4 to 1.6 and an outer layer having a geometric thickness of 50 to 140 nm. 2. A transparent layer including five layers formed on a substrate and having a refractive index of 1.4 to 2.3 in order from the substrate side.
A first layer having a geometric thickness of 0.5 to 250 nm,
A second layer mainly composed of a transition metal carbonitride or a transition metal carbonitride oxide, a transparent layer having a refractive index of 1.4 to 2.3 and a geometric thickness of 0.5 to 100 nm; And a fourth layer containing any one of transition metal nitride, transition metal carbonitride and transition metal carbonitride oxide as a main component, and a refractive index outside the fourth layer. Is 1.4 to 1.6
A conductive layer having a geometric thickness of 50 to 140 nm. 3. A transparent layer having six layers formed on a substrate and having a refractive index of 1.4 to 2.3 in order from the substrate side.
A first layer having a geometric thickness of 0.5 to 250 nm,
A second layer mainly composed of a transition metal carbonitride or a transition metal carbonitride oxide, a transparent layer having a refractive index of 1.4 to 2.3 and a geometric thickness of 0.5 to 100 nm; , A fourth layer containing any one of transition metal nitride, transition metal carbonitride and transition metal carbonitride as a main component, and a transparent layer having a refractive index of 1.4 to 3.0. A fifth layer having a geometric thickness of 0.5 to 40 nm, and a transparent layer having a refractive index of 1.4 to 1.6 outside the fifth layer,
A conductive anti-reflection film comprising an outer layer having a geometric thickness of 140 nm. 4. The conductive anti-reflection film according to claim 2 is formed on the outer surface of the face portion so that the average radius of curvature of the outer surface of the face portion is at the center of the face portion. 10,000 mm in all radial directions passing through
A glass panel for a cathode ray tube, wherein the glass panel has a light transmittance of 70% or more at a wavelength of 550 nm when the thickness is converted to 10.16 mm.