JPH11250836A - Panel for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a panel excellent in electromagnetic wave shielding property and reflection preventing property. SOLUTION: A first thin film (a refractive index of 1.75) 11 containing fine particles of ruthenium (Ru) and having a transmittance of 8O% and a thickness of 150 nm is formed at the outer surface of a panel glass (a refractive index of 1.536) 10 having a transmittance of 80% in a thickness of 10.16 mm at a wavelength of 546 nm. Furthermore, a second thin film (a refractive index of 2.3) 12 made of TiO2 having a thickness of 120 nm is formed on the first thin film 11. Moreover, a third thin film (a refractive index of 1.46) 13 made of SiO2 having a thickness of 90 nm is formed on the second thin film 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excellent electromagnetic shielding property,
The present invention relates to a CRT panel having antireflection properties and capable of adjusting brightness and contrast.

[0002]

2. Description of the Related Art A cathode ray tube is composed of a panel on which an image is displayed, a funnel and a neck which form the back of the panel.
Dust adheres to the outer surface and the image quality deteriorates,
Electric discharge may occur between the human body.

In the cathode ray tube, an electron beam emitted from an electron gun mounted in a neck tube is deflected by a deflection coil mounted around a funnel. In particular, an unnecessary electromagnetic wave generated from the deflection coil leaks, so that the cathode ray tube is leaked. There is a risk that other electronic devices around the tube may malfunction or have an adverse effect on the human body.

Therefore, conventionally, it has been attempted to form a transparent conductive film such as tin oxide (SnO ₂ ) having conductivity on the outer surface of the panel glass, thereby preventing charging and shielding electromagnetic waves.

However, since the SnO ₂ film has a refractive index of 2.0, which is higher than the refractive index (1.536) of the panel glass, the surface reflection increases when the SnO ₂ film is formed on the panel glass, Images are difficult to see.

[0006] In order to suppress the surface reflection is formed by forming a SnO ₂ film on a panel glass, thereon may be formed a lower antireflection film refractive index than SnO ₂ film, on the outer surface of, for example, the panel glass A transparent conductive film made of SnO ₂ is formed by the CVD method, and SiO ₂ is formed thereon by spin coating.
Attempts have been made to form an antireflection film made of a low refractive index material such as ₂ .

[0007]

[0005] However cathode ray tube panel SnO ₂ film and the SiO ₂ film is formed as described above, has the relatively good electromagnetic shielding properties by SnO ₂ film, SnO ₂ The thickness of the film is as thin as 20 to 40 nm, and its surface resistance (resistance per square) is 1 ×
Since it is as high as 10 ⁶ Ω / □ or more, it is still insufficient to completely block unnecessary electromagnetic waves.

An object of the present invention is to provide a cathode ray tube panel having excellent electromagnetic wave shielding and antireflection properties.

[0009]

The cathode ray tube panel of the present invention contains ruthenium fine particles on the outer surface side of the panel glass, has a thickness of 50 nm or more, a transmittance of 90% or less, and a surface resistance of 10% or less. ^A first thin film of ⁴ Ω / □ or less is formed, a second thin film having a higher refractive index than the first thin film is formed thereon, and a third thin film having a lower refractive index than the first thin film is further formed thereon. Characterized in that a thin film of

Further, the cathode ray tube panel of the present invention contains ruthenium fine particles on the outer surface side of the panel glass, has a thickness of 50 nm or more, a transmittance of 90% or less, and a surface resistance value of 10 ⁴ Ω / □ or less. Is formed, a second thin film having a higher refractive index than the first thin film is formed thereon, and a third thin film having a lower refractive index than the first thin film is further formed thereon. A fourth thin film having fine irregularities is formed on the outermost layer.

Further, the panel glass of the present invention is characterized by being formed of glass having a transmittance of 40% or more at a wavelength of 546 nm at a thickness of 10.16 mm.

[0012]

The fine particles of ruthenium (Ru) used in the present invention are highly conductive metal fine particles, and the thin film (first thin film) containing the fine particles acts as a conductive film. Further, since the ruthenium fine particles are black bodies and have an action of absorbing visible light, the amount of light transmitted through the first thin film is reduced.

The amount of transmitted light of the panel for a cathode ray tube affects the brightness and contrast when an image is displayed. That is, when the amount of transmitted light of the panel for a cathode ray tube is large and the transmittance is high, the luminance is increased and the contrast is reduced. Conversely, when the amount of transmitted light is small and the transmittance is low, the luminance is reduced and the contrast is improved.

Therefore, by appropriately combining the content of the ruthenium fine particles with the transmittance of the panel glass, it is possible to produce a cathode ray tube panel having various transmittances, and to adjust the brightness and the contrast.

By the way, the thickness of the panel glass for the cathode ray tube is different between the central part and the peripheral part in order to prevent explosion. Therefore, if the transmittance of the panel glass is low, a difference in transmittance occurs between the central portion and the peripheral portion, and a difference in brightness and contrast occurs when an image is displayed. Therefore, in the present invention, as the panel glass, a glass having a high transmittance, specifically, a thickness of 10.000 at a wavelength of 546 nm.
It is desirable to use glass whose transmittance at 16 mm is 40% or more. That is, when such a panel glass having a high transmittance is used, a difference in brightness and contrast between the central portion and the peripheral portion is reduced by forming a first thin film having a low transmittance on the panel glass.

In the present invention, the transmittance of the first thin film is 90
% Or less and the film thickness is 50 nm or more, the surface resistance becomes 10 ⁴ Ω / □ or less, and excellent electromagnetic wave shielding properties are obtained. Considering the surface resistance, the desired transmittance of the first thin film is 80% or less.

However, if the content of the ruthenium fine particles in the first thin film is increased and the transmittance becomes too low, the luminance of the panel for a cathode ray tube becomes too low. Therefore, the transmittance is preferably 60% or more. . Considering the brightness, the desirable transmittance of the first thin film is 70% or more.

The average particle size of the ruthenium fine particles is 50
nm or less is appropriate, and it is preferable to attach an inorganic compound such as Si to the surface because the surface resistance value of the first thin film is more likely to decrease.

In order to form the first thin film on the outer surface side of the panel glass, first, a solvent in which ruthenium fine particles are uniformly dispersed in an organic solvent such as ethanol is applied to the panel glass and then fired at a predetermined temperature. A method is adopted. When dispersing the ruthenium fine particles in the solvent, it is preferable to add a silicate because the strength of the film is improved. However, as the amount of silicate added increases, the surface resistance of the film increases, so that the weight ratio of SiO ₂ / Ru is set to be less than 1/10.

In the present invention, as a method for applying a solvent in which ruthenium fine particles are dispersed in an organic solvent on a panel glass, a spin coating method, a dip coating method, a spraying method or the like can be adopted. To get
Spin coating is most suitable.

The refractive index of the first thin film containing the fine particles of ruthenium is 1.8 to 2.3, which is higher than the refractive index of the panel glass, so that the surface reflection increases and the image becomes difficult to see. Therefore, in the present invention, on the first thin film,
A second thin film having a higher refractive index than the first thin film is formed, and a third thin film (anti-reflection film) having a lower refractive index than the first thin film is formed thereon, thereby suppressing surface reflection. I have to.

The constituent materials of the second thin film include TiO ₂ , In ₂ O ₃ , and Nd ₂ O having a higher refractive index than the first thin film.
_{3, Sb 2 O 3, ZrO} 2, CeO 2, ZnS, Bi 2
O ₃ , ZnSe, CdS, La ₂ O ₃ or the like can be used. As the third thin film, SiO 3 having a lower refractive index than the first thin film is used.
₂ , MgF ₂ , CaF ₂ , Al ₂ O _3, etc. can be used, but in consideration of material cost and film strength, SiO ₂ (refractive index: 1.46) is preferable. Method, dip coating method, or spray coating method.

Further, when a fourth thin film having fine irregularities is formed on the third thin film, diffuse reflection when light is irradiated from the outside becomes large, and conversely, regular reflection becomes small. The effect will be obtained. As the fourth thin film, a film obtained by spray-coating a solution containing Si alkoxide to form a SiO ₂ film having irregularities on the surface is preferable.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cathode ray tube panel of the present invention will be described in detail based on examples and comparative examples.

(Embodiment 1) FIG. 1 is a schematic longitudinal sectional view of a panel for a cathode ray tube of the present invention.

In the figure, at a wavelength of 546 nm, a thickness of 1
On the outer surface side of the panel glass (refractive index: 1.536) 10 having a transmittance of 80% at 0.16 mm, ruthenium (R
u) A first thin film (refractive index: 1.75) 11 containing fine particles, having a transmittance of 80%, and having a thickness of 150 nm is formed, and a first TiO ₂ film having a thickness of 120 nm is formed thereon. A second thin film (refractive index 2.3) 12 is formed thereon, and a third thin film (refractive index 1.46) 13 which is a SiO ₂ film having a thickness of 90 nm is formed thereon.

The method for producing the panel for a cathode ray tube is as follows.

First, the panel glass 10 is washed, dried, rotated in a preheated state, and a solvent in which ruthenium fine particles are dispersed in an organic solvent is dropped thereon, then naturally dried, and then fired. One thin film 11 was formed.

Next, the panel glass 10 is again rotated in a preheated state, a solvent in which titania fine particles are dispersed in an organic solvent is dropped on the first thin film 11, and the panel glass 10 is air-dried. A thin film 12 was formed, and an alcohol solution containing SiO ₂ was dropped on the second thin film 12, then allowed to dry naturally, and then fired to form a third thin film 13.

[0030] The surface resistance value of the resultant cathode ray tube panel thus determined, 6 × 10 ² Ω / □ and lower, had excellent electromagnetic wave shielding property.

(Embodiment 2) FIG. 2 is a schematic longitudinal sectional view of a panel for a cathode ray tube of the present invention.

In the figure, on the outer surface side of the panel glass 10,
A first thin film 11 containing ruthenium fine particles is formed, a second thin film 12 having a higher refractive index than the first thin film is formed thereon, and a third thin film having a lower refractive index than the first thin film is formed thereon. 13 is formed, and a fourth thin film 14 having fine irregularities is formed on the outermost layer.

This cathode ray tube panel is formed by forming a first thin film 11, a second thin film 12, and a third thin film 13 on a panel glass 10 in the same manner as in the first embodiment, and further forming a SiO ₂ film thereon. The fourth thin film 14 was formed by spray-coating an alcohol solution containing, and naturally drying and baking to form a fourth thin film 14.

When the surface resistance value of the cathode ray tube panel thus obtained was measured, it was as low as 6 × 10 ² Ω / □, indicating that the panel had excellent electromagnetic wave shielding properties.

(Comparative Example) C on the outer surface side of the panel glass
A panel for a cathode ray tube is manufactured by forming a SnO ₂ film having a thickness of 27 nm by a VD method, and forming a SiO ₂ film having a thickness of 100 nm by a spin coating method thereon, and a surface of the panel for a cathode ray tube is formed. When the resistance value was measured, it was 5 × 10 ⁵ Ω / □, which was higher than in Examples 1 and 2.

When the reflectances of the cathode ray tube panels of Examples 1 and 2 at wavelengths of 400 to 700 nm were measured, as shown in the graph of FIG. 3, all of them had a low reflectance over a wide range and were excellent. It also had antireflection properties. Further, when the luminous transmittance of these cathode ray tube panels was measured, as shown in the graph of FIG. 4, the same transmittance curve was drawn in all cases, and was about 50%.

The above surface resistance value is measured by a super insulation resistance meter manufactured by Toa Denpa Co., Ltd. The reflectance is measured by MCPD1000 15 ° regular reflection manufactured by Otsuka Electronics Co., Ltd. And a U-4000 spectrophotometer manufactured by Hitachi, Ltd.

[0038]

As described above, the cathode ray tube panel of the present invention has excellent electromagnetic wave shielding and antireflection properties, and can adjust brightness and contrast.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing a panel for a cathode ray tube of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing another panel for a cathode ray tube of the present invention.

FIG. 3 shows a wavelength 400 of the cathode ray tube panel of Examples 1 and 2.
It is a graph which shows the reflectance curve in -700 nm.

FIG. 4 shows a wavelength 400 of the cathode ray tube panel of Examples 1 and 2.
It is a graph which shows the transmittance curve in -700 nm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Panel glass 11 1st thin film 12 2nd thin film 13 3rd thin film 14 4th thin film

Claims (4)

[Claims] 1. A first thin film containing ruthenium fine particles, having a film thickness of 50 nm or more, a transmittance of 90% or less, and a surface resistance value of 10 ⁴ Ω / □ or less, is provided on the outer surface side of the panel glass. And a second thin film having a higher refractive index than the first thin film is formed thereon, and a third thin film having a lower refractive index than the first thin film is further formed thereon. Panel for cathode ray tube. 2. The panel for a cathode ray tube according to claim 1, wherein the panel glass is formed of glass having a transmittance of 40% or more at a wavelength of 546 nm and a thickness of 10.16 mm. 3. A first thin film containing ruthenium fine particles, having a thickness of 50 nm or more, a transmittance of 90% or less, and a surface resistance of 10 ⁴ Ω / □ or less, is provided on the outer surface side of the panel glass. Is formed thereon, a second thin film having a higher refractive index than the first thin film is formed thereon, and a third thin film having a lower refractive index than the first thin film is further formed thereon. A panel for a cathode ray tube, wherein a fourth thin film having the following is formed. 4. The panel for a cathode ray tube according to claim 3, wherein the panel glass is formed of glass having a transmittance of 40% or more at a wavelength of 546 nm and a thickness of 10.16 mm.