JPH11120942A - Cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode-ray tube having high conductivity effective for preventing the leakage electric field(AEF) and having a high-intensity, high- contrast reflection preventing film. SOLUTION: A reflection preventing film 8 laminated with two or more conductive layers made of conductive fine grains is provided on the outer surface of the face panel 3 of this cathode-ray tube, and the reflection preventing film 8 has the light transmission factor T of 80% or above and the H-inter- terminal resistance value R of 1×10<6> Ω or below. R indicates a value of 1×10<4> Ωor below when T is 80% or below, and R indicates a value of 1×10<6> Ω or below when T is 85%. When the differentiated value d(log R)/dT of the logarithm R of T is 1 or below, good AEF prevention stable against the change of the environmental condition is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer surface of a front panel (face panel) of a face plate, which functions as an anti-reflection film and has a leakage electric field (AEF; Alternating).
The present invention relates to a cathode ray tube having a conductive film for preventing electric field.

[0002]

2. Description of the Related Art In recent years, in a cathode ray tube such as a TV cathode ray tube or a CRT of a computer, there is a concern that electromagnetic waves generated from the vicinity of an internal electron gun and a deflection yoke may leak and adversely affect peripheral electronic devices and the human body. Have been. In order to prevent such leakage of the electromagnetic wave (electric field), it is necessary to form a conductive film on the outer surface of the face panel of the cathode ray tube to lower the surface resistance.

Further, since the smaller the specific resistance of the conductive material constituting the conductive film is, the better the conductivity is obtained, the use of a film of metal fine particles or metal compound fine particles effectively generates a leak electric field (AEF). Is known to be prevented.

[0004]

However, since a film of metal fine particles or metal compound fine particles generally has absorption in the visible light region even if it is a thin film, if the film thickness is increased to reduce the resistance value, the light emission of the light is reduced. There is a problem that the transmittance is reduced and the luminance of the cathode ray tube is reduced.

The present invention has been made to solve such a problem, and has a low resistance effective for preventing AEF.
It is another object of the present invention to provide a cathode ray tube having an antireflection film capable of obtaining high brightness and high contrast.

[0006]

A cathode ray tube according to the present invention has at least one conductive layer made of conductive fine particles on an outer surface of a front panel of a face plate. In a cathode ray tube having an antireflection film formed by stacking two or more layers, the antireflection film has a light transmittance T of 70% or more.
And an electrical resistance value R between the horizontal ends of the panel of the antireflection film is 1 × 10 ⁶ Ω or less.

In the cathode ray tube of the present invention, the conductive layer made of conductive fine particles is a high refractive index layer (with a refractive index of 2 or more),
On the outer surface of the face panel, there are provided two or three or more antireflection films on which a low-refractive-index layer made of silica (SiO ₂ ) or the like having a refractive index of 2 or less is provided. The film thickness of each layer of the antireflection film is set to 1/4 (1 / 4λ) of the design wavelength λ. In order to form such an anti-reflection film, a coating layer composed of conductive fine particles is formed on the outer surface of the face panel, and then a coating layer mainly composed of silicate is formed immediately above the coating layer. Are fired simultaneously.

Here, as the conductive fine particles, fine particles of a metal such as silver or fine particles of a metal compound such as tin oxide or a silver compound are used. Examples of the silver compound include silver oxide, silver nitrate, and silver acetate. Silver benzoate, silver bromate, silver bromide, silver carbonate, silver chloride, silver chromate, silver citrate, silver cyclohexane butyrate, and the like.

In the present invention, in such an antireflection film, a resistance value R between horizontal edges of the panel (hereinafter referred to as an H-end resistance value) is an electric resistance value closely related to the size of AEF. The value is limited to a range of 1 × 10 ⁶ Ω or less, and the light transmittance T of the antireflection film is set to 70% or more in order to obtain a sufficient luminance. Note that the H end-to-end resistance value R
Is the electrical resistance value between the H-ends, which are the midpoints of the short sides (vertical sides) of the panel. The measurement is performed by placing solder or the like directly above the so-called register marks at the H-ends on both short sides of the face panel. Is performed by measuring the resistance value between these terminals.

The above-mentioned range of the H-end resistance value R is determined from the following measurement results.

That is, a two-layer antireflection film having a layer mainly composed of SiO ₂ is formed immediately above a conductive layer mainly composed of various kinds of conductive fine particles. The resistance value R and the AEF (VLF band) value were measured. The measurement of the AEF value was performed by a predetermined method of TCO (Guideline of Swedish Safety Council). FIG. 1 shows the measurement results.

From the graph of FIG. 1, it can be seen that, in such a two-layer antireflection film, the AEF value decreases as the H end-to-end resistance value R decreases. In addition, the resistance R between H ends effective for preventing AEF is 1 × 10 ⁶ Ω or less, more preferably 1 × 10 ⁶ Ω or less.
A range of × 10 ⁴ Ω or less is set. Further, since the AEF value by TCO is 1.0 V / m or less, the AEF-TCO
In response, it can be seen that the resistance R between H ends of the antireflection film must be 1 × 10 ₅ Ω or less.

Further, regarding the light transmittance T of the antireflection film, conventionally, when the transmittance T is 80%, the ratio of the brightness of the bright portion (light emitting portion) to the brightness of the dark portion (non-light emitting portion) of the screen. It is known that certain contrasts are best. That is,
When the transmittance T of the anti-reflection film is less than 80%, the brightness of the bright part is too low, so that the contrast is low. Conversely, when the transmittance exceeds 80%, the brightness of the bright part and the dark part is low. Are both too high, so that the contrast is known to be lower than when the transmittance is 80%. Therefore, in the present invention, when the transmittance of the antireflection film is set to 80%, a screen having the highest contrast can be obtained.

Further, in the present invention, a differential value d (logR) / dT of the logarithm of R with respect to the transmittance T is considered as a numerical value indicating the stability of the resistance R between H ends of such an antireflection film. It is desirable to provide an antireflection film having a value of 1 or less. That is, under various forced environments,
The transmittance T of the anti-reflection film may vary by about ± 1%, and the transmittance T fluctuates by about 2% up and down with respect to a set value in consideration of manufacturing variations.
Change in H end-to-end resistance R (logarithm of) with respect to change in d
In an antireflection film having an excessively large (logR) / dT, when the transmittance changes due to a change in the environment or the like, the resistance R between the H ends is reduced.
The resistance becomes 1 × 10 ⁶ Ω or more, and there is a possibility that AEF is not supported.

Therefore, in order to obtain a cathode ray tube capable of stably preventing AEF in response to changes in environmental conditions and the like, it is particularly desirable to provide an antireflection film having d (logR) / dT of 1 or less.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view showing the structure of a color cathode ray tube according to one embodiment of the present invention. As shown in the figure, the color cathode ray tube of the embodiment includes a panel 1 and the panel 1.
A three-color phosphor layer that emits blue, green, and red light, respectively, is provided on an inner surface of the face panel 3 incorporated in the panel 1 and a funnel 2 integrally formed with the funnel 2. The phosphor screen 4 is formed of a black light absorbing layer (black matrix) that fills the gap between the phosphor layers. The three-color phosphor layer is composed of PVA, blue, green, and red phosphors.
The slurry is obtained by applying a slurry dispersed together with a surfactant, pure water and the like to the inner surface of the face panel 3 by an ordinary method. The shape of the three-color phosphor layer may be a stripe shape or a dot shape.

A shadow mask 5 having a large number of electron beam passage holes formed therein is mounted opposite to and inside the fluorescent screen 4. An electron gun 7 for irradiating the phosphor screen 4 with an electron beam is disposed inside the neck portion 6 of the funnel 2, and the electron beam emitted from the electron gun 7 passes through the shadow mask 5. It is configured to collide with the phosphor screen 4 through the hole to excite and emit the three-color phosphor layer. Further, a conductive antireflection film 8 described below is formed on the outer surface of the face panel 3.

FIG. 3 shows a cross section of the cathode ray tube shown in FIG. 2 cut along the line AA '. As shown in this figure,
On the outer surface of the face panel 3, a conductive antireflection film 8 composed of a conductive layer 10 containing conductive fine particles 9 such as silver compound fine particles and a second layer 11 containing SiO ₂ as a main component is provided. Is formed. The conductive anti-reflection film 8 has a light transmittance T of 80% and a resistance value R between H ends of the panel of 1 × 10 ⁶ Ω or less. Also, the differential value d of the logarithm of the H end-to-end resistance value R with respect to the transmittance T
(logR) / dT is 1 or less.

In the color cathode ray tube of the embodiment constructed as described above, the conductive anti-reflection film 8 stably realizes a low resistance effective for preventing the generation of AEF and has a high contrast. can get.

Next, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the following examples.

Examples 1 to 3 Silver fine particles, Ag ₂ O, AgNO
_3. Dissolve silver compound fine particles such as AgCl and tin oxide fine particles in 100 g of water, respectively, and disperse silver fine particle dispersion liquid (a), silver compound fine particle dispersion liquid (b) and tin oxide fine particle dispersion liquid (c) at various concentrations. ) Was prepared respectively.

A silicate solution comprising 8 parts by weight of methyl silicate, 0.03 parts by weight of nitric acid, 500 parts by weight of ethanol and 15 parts by weight of water was prepared as an upper layer coating solution.

Next, the outer surface of the cathode ray tube face panel (17-inch panel) after the assembly is finished is buffed with cerium oxide to remove dust, dust, oil and the like. A film was formed by coating by spin coating. In Example 1, the silver fine particle dispersion (a) was applied, and in Example 2, the silver compound fine particle dispersion (b) was applied. In Example 3, the tin oxide fine particle dispersion (c) was applied. The application conditions are panel (application surface) temperature of 45 ° C,
The rotation speed is 80rpm-5sec at the time of liquid injection, and at the time of liquid sweeping (film formation)
150 rpm-80 sec. Then, the upper layer coating solution on the lower layer coating film, 80rpm-5sec at the time of liquid injection, 150rpm-
After coating and film formation by spin coating under the conditions of 80 sec, the upper and lower layers were baked at a temperature of 210 ° C. for 30 minutes.

Next, with respect to the surface-treated films obtained in Examples 1 to 3, the H-end resistance R and the light transmittance T of the panel were measured. The measurement of the resistance between H ends is 17
A special solder was attached to both H ends of the inch panel using an AGC Cerasolzer to form terminals, and the resistance between these terminals was measured by a tester. Also, using MINOLTA CM-1000 (manufactured by Minolta), the external light reflectance Y _{0 of} the panel before surface treatment and the external light reflectance Y of the surface treatment film were measured, and (Y / Y ₀ ) ^1/2
Was defined as the membrane transmittance. The measurement results are shown in FIG. 4 in which the resistance R between the ends is plotted against the transmittance T.

From the graph of FIG. 4, it can be seen that the surface treatment films obtained in Examples 1 to 3 each have a light transmittance T of 70% or more, can obtain high luminance, and have an H end. There was a region where the inter-resistance value R was 1 × 10 ⁶ Ω or less, and it was found that the film had high conductivity effective for preventing AEF. In particular, Example 2
When the transmittance T is 80% or less,
1 × 10 ⁴ Ω or less, the transmittance T is found to have a 1 × 10 ⁶ Ω or less in the case of 85%, a very high conductivity corresponding to AEF-TCO. In the surface treatment film of Example 2, the differential value of the logarithm of the resistance value R between the ends H with respect to the transmittance T was obtained.
d (logR) / dT was 1 or less, indicating that AEF prevention was stably performed even when environmental conditions and the like changed.

[0027]

As is apparent from the above description, according to the present invention, a low-reflection antireflection film having high luminance, high contrast, stable against changes in environmental conditions and the like, and effective in preventing AEF is obtained. As a result, a high-performance cathode ray tube can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a resistance value between H ends of an antireflection film and an AEF value.

FIG. 2 is a perspective view showing the structure of a color cathode ray tube according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view of the cathode ray tube of FIG. 2 cut along AA ′.

FIG. 4 is a graph showing the results of measuring the resistance between H ends and the transmittance of the antireflection film obtained in the example.

[Explanation of symbols]

3 and mainly composed of ......... face panel 4 ......... phosphor screen 5 ......... shadow mask 8 ......... conductive antireflection film 9 ......... conductive particles 10 ......... conductive layer 11 ......... SiO ₂ Second layer

Claims (3)

[Claims] 1. An anti-reflection film having at least one conductive layer made of conductive fine particles on an outer surface of a front panel of a face plate, and a laminate of two or more layers including the conductive layer. In the cathode ray tube, the antireflection film has a light transmittance T of 70% or more, and the electric resistance value R between the horizontal ends of the panel of the antireflection film is:
A cathode ray tube characterized by being 1 × 10 ⁶ Ω or less. Wherein the electrical resistance R between the horizontal edge of the antireflection film, 1 × 10 ⁴ Omega hereinafter the transmittance T of 80% or less, the transmittance T is 1 × 10 in the case of 85% ⁶ Ω or less, and the differential value of the logarithm of the horizontal end-to-end resistance value R with respect to the transmittance T
2. The cathode ray tube according to claim 1, wherein d (logR) / dT is 1 or less. 3. The cathode ray tube according to claim 1, wherein the transmittance T of the antireflection film is 80%.