JP2001226147A - Electrically conductive antireflection film and glass panel for cathode ray tube on which the film is deposited - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare an electrically conductive antireflection film which can attain reduction of reflected light and improvement of contrast, has excellent ability of antistatic effect and electromagnetic wave shielding and further is excellent in heat resistance and to provide a glass panel for a cathode ray tube on an outer surface of a face part of which the electrically conductive antireflection film is deposited. SOLUTION: The electrically conductive antireflection film contains four layers formed on a base body and is constituted by providing (in order starting from the base body side), a first layer which is a transparent layer having 1.4 to 2.3 refractive index and 0.5 to 250 nm geometrical thickness, a second layer which is a colored electrically conductive layer consisting essentially of a transition metal nitride and has 1.1 to 3.0 refractive index and 0.5 to 40 nm geometrical thickness, a third layer which is a transparent layer of 1.4 to 2.3 refractive index and has 0.5 to 100 nm geometrical thickness and further an external layer which is a transparent layer of 1.4 to 1.6 refractive index and has 50 to 140 nm geometrical thickness outside 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 on the outer surface of the face portion.

[0002]

2. Description of the Related Art Conventionally, a cathode ray tube has been required to reduce reflected light and to improve contrast. Recently, it has been required to prevent charging and to shield electromagnetic waves which have an adverse effect on the human body. It is becoming.

[0003] Therefore, by forming a conductive anti-reflection coating on the outer surface of the face portion 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 are prevented. It has been proposed to provide a shielding function.

For example, Japanese Patent Publication No. Hei 6-510382 proposes a conductive antireflection film comprising 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 furthermore, is colored. 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. It is hard to obtain.

It is an object of the present invention to provide a conductive antireflection film which can reduce reflected light and improve contrast, has excellent antistatic properties and electromagnetic wave shielding properties, and has excellent heat resistance. Another object of the present invention is to provide a glass panel for a cathode ray tube in which the conductive antireflection film is formed on 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 colored conductive layer of 3.0, a second layer having a geometric thickness of 0.5 to 40 nm, and a transparent layer having a refractive index of 1.4 to 2.3, a geometric layer of 0.5 to 100 nm. The third with the target thickness
And a third layer having a refractive index of 1.
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 anti-reflection 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. .5-25
A first layer having a geometric thickness of 0 nm and a colored conductive layer having a refractive index of 1.1 to 3.0 and containing a transition metal nitride as a main component have a geometric thickness of 0.5 to 40 nm. And a transparent layer having a refractive index of 1.4 to 2.3.
A third layer having a geometric thickness of 00 nm and a colored conductive layer having a refractive index of 1.1 to 3.5 and containing a transition metal nitride as a main component, and having a geometric thickness of 0.5 to 40 nm. Fourth
And a refractive index of 1. outside the fourth 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.

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 and a colored conductive layer having a refractive index of 1.1 to 3.0 and containing a transition metal nitride as a main component have a geometric thickness of 0.5 to 40 nm. Having a second
And a transparent layer having a refractive index of 1.4 to 2.3.
A third layer having a geometric thickness of 100 nm and a colored conductive layer having a refractive index of 1.1 to 3.5 and containing a transition metal nitride as a main component have a geometric thickness of 0.5 to 40 nm. And a transparent layer having a refractive index of 1.4 to 3.0,
A fifth layer having a geometric thickness of ４０40 nm;
Further, a transparent layer having a refractive index of 1.4 to 1.6 and an outer layer having a geometric thickness of 50 to 140 nm are provided outside the fifth layer.

Further, the glass panel for a cathode ray tube of the present invention comprises:
The conductive antireflection film including the above five layers or six layers is formed on the outer surface of the face portion, and 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. , And is characterized by being made of glass having a light transmittance of 70% or more at a wavelength of 550 nm when the thickness is converted to 10.16 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 nitride as a main component and having a refractive index of 1.1 to 3.0.
It has a geometric thickness of ４０40 nm, imparts conductivity to the film, reduces the surface reflected light by the interference effect with other layers, and widens the low-reflection region in the visible light region. Having. 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 this second layer,
A film mainly composed of a nitride of a metal selected from Ti, Zr, Hf and Nb is suitable. In particular, when a film mainly composed of a nitride of Ti is used, a low reflection region in a visible light region is reduced. It is preferable because it becomes wider. When a film containing Ti nitride as a main component is used, the atomic ratio of N to Ti in the layer is desirably 0.75 to 1.30 from the viewpoint of preventing reflection. It is preferable that O (oxygen) be contained in this layer so that the atomic ratio to Ti is 0.5 or less, since the conductivity is further improved.

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. As the material of the third layer, one selected from the group consisting of SiO ₂ , Si ₃ N ₄ , SiON, Al ₂ O ₃ and AlON is suitable in consideration of film forming properties, production costs, and the like. In particular, it is preferable to use Si ₃ N ₄ as a material for the first layer and the third layer, since extremely 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. Are designed such that the radius of curvature of the inner surface of the is reduced. As a result, 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 transmitted light due to the difference in thickness between the central portion and the peripheral portion of the face portion becomes large, and the central portion and the peripheral portion 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, the brightness of the peripheral portion is prevented from being extremely reduced compared to the central portion of the face portion, and a colored film is formed on the outer surface of the face portion. 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 Application Laid-Open No. 382 and Japanese Patent Application Laid-Open No. 9-156964 has a problem that the effect of reducing the reflected light on the back surface of the face portion is small. The higher the light transmittance of the glass, the higher the reflectance of the back surface. Therefore, the conventional conductive anti-reflection film as described above is coated on the outer surface of the face portion of the flat glass panel made of the glass having a high 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 anti-reflection film, between the third layer and the outer layer, a transition metal oxide as a main component and a refractive index of 1.1 to 3.5 are used. (Preferably 1.1 to 3.0) colored conductive layer, and 0.5 to 4
A layer (fourth layer) having a geometric thickness of 0 nm was formed. By adding this layer, it is possible to reduce the front surface reflected light and the back surface reflected light by an interference effect with other layers. 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 the fourth layer, a film mainly composed of a nitride of a metal selected from Ti, Zr, Hf, and Nb can be used. This is preferable because the low reflection region in the region becomes wider. When a film containing a nitride of Ti as a main component is used, the atomic ratio of N to Ti in the layer is 0.75 to 1.30 from the viewpoint of preventing reflection.
It is desirable that Similarly to the second layer, it is preferable that O (oxygen) be contained in this layer so that the atomic ratio to Ti is 0.5 or less, since conductivity is further improved.

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, 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. This fifth layer is made of Si ₃ N ₄ , AlN, SiON, AlON, Ti
O, Ti ₂ O ₃ , TiO ₂ , Ta ₂ O ₅ , CeO ₂ , ZnO,
It is preferably a layer composed of one selected from the group consisting of Nb ₂ O ₅ , Nd ₂ O ₃ , Sb ₂ O ₃ , HfO ₂ , In ₂ O ₃ and SnO ₂ . In particular, when a layer of nitride such as Si ₃ N ₄ or AlN is used, this layer becomes a barrier layer for oxygen in air,
This is preferable because the oxidation of the TiN layer during the heat treatment is completely prevented, and the reflectance and the resistance value of the film after the heat treatment are more easily 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. The radius of curvature of the inner surface is reduced in view of the strength of the second and third surfaces according to the present invention described above.
Of a conductive anti-reflection film.

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 becomes a slightly curved surface, and the radius of curvature of the inner surface can be increased. No conductive anti-reflection film is required. That is, such a glass panel for a cathode ray tube,
This is because the difference in thickness between the central portion and the peripheral portion of the face portion can be reduced, so that it is not necessary to use a glass having a high light transmittance, that is, a glass that easily reflects on the back surface.

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 luminance difference 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 17) and the conductive anti-reflection coatings of Comparative Examples (Sample No. 18). 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 on the outer surface of the face portion (in all radial directions passing through the center of the face portion) is 50,000 mm.
Wavelength 550 nm when the thickness is converted to 10.16 mm
A glass panel (17-inch size) 10 for a cathode ray tube made of glass having a light transmittance of 80% is prepared. A conductive antireflection film 11 having a layer structure was formed. In the column of membrane composition in the table,
The material of each film layer and the geometric thickness are shown. In addition, No. 2
The sample had a second layer of Ti: N: O = 1: 0.93: 0.
The atomic ratio was 19.

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 17 was No. 1 as a comparative example. As compared with the sample No. 18, the surface reflectance and the resistance at wavelengths of 550 nm and 620 nm after the heat treatment were significantly lower, and the adhesion strength between the film and the glass panel was excellent. Moreover, in the example No.
Since each of the samples Nos. 5 to 17 also has a low back surface reflectance, it is presumed that double reflection of an image of a cathode ray tube can be prevented. 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 determined by attaching an electrode to the center of the face portion of the glass panel on the short side with an ultrasonic solder.
The resistance between the electrodes was measured 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 to reduce reflected light, improve contrast, prevent electrostatic charge and shield electromagnetic waves, has excellent heat resistance, and is 400 ° C. or more. Since the surface reflectance and the resistance value after the heat treatment are low, it is suitable as a conductive antireflection film formed on a glass 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 flat 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 of the present invention is a flat glass panel having an outer surface of the face portion having an average radius of curvature of 10,000 mm or more in all radial directions passing through the center of the face portion, but having a thickness of 10.16 m.
It is formed of glass having a light transmittance of 70% or more at a wavelength of 550 nm when converted to m. Therefore, in this glass panel, the difference in luminance between the central portion and the peripheral portion of the face portion is small. Moreover, the above-mentioned 5 is provided on the outer surface of the face portion.
Or a conductive anti-reflection film containing six layers is formed by coating, so that the surface reflectance is low, the contrast is high, the anti-static property and the electromagnetic wave shielding property are excellent, and the back face reflectance is low. Therefore, it is possible to obtain a cathode ray tube in which an image does not look 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

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) H01J 29/88 G02B 1/10 A (31) Priority claim number Japanese Patent Application No. 11-350096 (32) Priority date December 9, 1999 (12.9 December 1999) (33) Countries claiming priority Japan (JP) F-term (reference) 2K009 AA07 AA08 BB02 CC02 CC03 DD03 DD04 EE01 EE03 4G059 AA06 AC04 AC08 AC11 EA01 EA05 EA12 GA02 GA04 GA12 5C032 AA02 DD02 DE01 DF01 DF03 DF05 DG01 DG02 5G435 AA02 BB02 FF14 GG11 GG33 HH03 HH12

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 colored conductive layer of 3.0, a second layer having a geometric thickness of 0.5 to 40 nm, and a transparent layer having a refractive index of 1.4 to 2.3, a geometric layer of 0.5 to 100 nm. The third with the target thickness
And a third layer having a refractive index of 1.
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 colored conductive layer of 3.0, a second layer having a geometric thickness of 0.5 to 40 nm, and a transparent layer having a refractive index of 1.4 to 2.3, a geometric layer of 0.5 to 100 nm. The third with the target thickness
Layer having a refractive index of 1.1 mainly containing a transition metal nitride.
And a fourth layer having a geometric thickness of 0.5 to 40 nm, and further having a refractive index of 1.4 to 1.6 outside the fourth layer. 50-140 with transparent layer
A conductive anti-reflection film comprising an outer layer having a geometric thickness of 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 colored conductive layer of 3.0, a second layer having a geometric thickness of 0.5 to 40 nm, and a transparent layer having a refractive index of 1.4 to 2.3, a geometric layer of 0.5 to 100 nm. The third with the target thickness
And a layer having a refractive index of 1.1 containing a transition metal nitride as a main component.
A colored conductive layer having a geometrical thickness of 0.5 to 40 nm; a transparent layer having a refractive index of 1.4 to 3.0; Fifth with geometric thickness
And a refractive index of 1. outside the fifth layer.
A conductive anti-reflection film comprising a transparent layer of 4-1.6 and an outer layer having a geometric thickness of 50-140 nm. 4. The conductive antireflection film according to claim 2 is formed on the outer surface of the face portion, and the average radius of curvature of the outer surface of the face portion is equal to that of the face portion. 100 in all radial directions through the center
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 converted to a thickness of not less than 00 mm and 10.16 mm.