JPH01286236A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To improve the reflection coefficient of the metal back and obtain a cathode-ray tube with high intensity by forming at least the phosphor layer contact face of an intermediate film with polyvinyl alcohol-stilbazolium photosensitive resin. CONSTITUTION:Carbon stripes 2 are formed on a glass panel 1 at a preset interval, a phosphor layer 3 dispersed with one of red, green and blue phosphor grains is formed in sequence to bury gaps between the carbon stripes 2. Irregularities generated on the surface of the layer 3 are effectively dissolved by a smoothing film 4 formed with polyvinyl alcohol-stilbazolium photosensitive resin on it. The metal beck 6 is laminated on the film 4 via an intermediate film 5. Irregularities on the surface of the phosphor layer is dissolved even when a material with a large grain size is used for the phosphor grains, the surface of the metal back can be finished nearly to the mirror face state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cathode ray tube with ultra-high definition, and particularly to a cathode ray tube with high brightness.

[Conventional technology]

BACKGROUND ART Cathode ray tubes, particularly color cathode ray tubes, used as projection tubes in projection televisions, so-called projection-type television receivers, are generally required to have extremely high brightness. Especially in beam index tubes,
If the beam spot is made small enough to prevent a decrease in color purity, the brightness tends to decrease, so the development of high-brightness cathode ray tubes is essential.

One possible technique for improving the brightness of conventional cathode ray tubes is to increase the particle size of the phosphor particles applied to the phosphor screen.

Alternatively, a technique already applied to most types of cathode ray tubes is the so-called metal back, in which a thin aluminum film with high light reflectance and good electron transmittance is attached to the back of the phosphor screen using the vacuum one-layer method. ing. this is,
This device improves the brightness of the screen by reflecting the light emitted by the phosphor when it is excited by an electron beam toward the front, as well as preventing ion burnout and stabilizing the potential of the phosphor screen. It is.

Figure 2 shows an example of the phosphor screen of a striped cathode ray tube with a metal back.
1) Carbon stripes (12) are formed at predetermined intervals on the carbon stripe (12), and a phosphor layer (13) in which phosphor particles are dispersed is formed between the carbon stripes (12). An intermediate film (14) is provided on the phosphor layer (13) for the purpose of smoothing the surface thereof, and a metal back (15) is further formed on the intermediate film (14).

It is already known that in such a cathode ray tube, the brightness of the screen largely depends on the mirror surface condition of the metal back, and that this mirror surface condition is determined by the smoothness of the surface of the interlayer film. This intermediate film is usually formed to have a thickness of 2N. The first layer, that is, the side that contacts the phosphor layer, is used to prevent aluminum, which is the material of the metal back, from entering the phosphor screen and provide a smooth reflective surface. The side that comes into contact with is provided for the purpose of facilitating gas dispersion when the intermediate film is thermally decomposed and removed by subsequent baking, and thereby preventing peeling of the metal back, so-called aluminum floating. A flexible acrylic resin, a photosensitive resin, or the like is used as the material for the first interlayer film, and a hard acrylic resin or the like is used as the material for the 21st J interlayer film. Therefore, it is important that the first interlayer film be formed smoothly.

As an attempt to improve the smoothness of the first interlayer film, for example, Japanese Patent Laid-Open No. 56-82545 discloses a technique of forming the first interlayer film using a photosensitive resin. ing. Here, by repeating coating of photosensitive resin and exposure through a predetermined mask, the thickness of the ti-th intermediate film laminated on the phosphor layer of the color cathode ray tube is changed for each color, and the metal Controls the mirror state of the background.

[Problem to be solved by the invention]

However, in recent years, materials with large particle sizes have been used as phosphor particles dispersed in the phosphor layer in some cathode ray tubes, and there has been a tendency for the surface irregularities of the phosphor layer to increase. In order to smooth the surface of such a phosphor layer, for example, if an attempt is made to form a 1Nth interlayer film by coating a conventional photosensitive resin slurry, the photosensitive resin will penetrate into the gaps between the particles. Increasing the thickness of the interlayer film to solve this problem is accompanied by difficulty in coating, and increasing the slurry concentration makes it difficult to form a good interlayer film. Therefore, the reality is that it is difficult to obtain a sufficient smoothing effect with conventionally used resins.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a cathode ray tube with high brightness.

[Means to solve the problem]

The present invention is proposed in view of such conventional circumstances. That is, the cathode ray tube according to the present invention is a cathode ray tube having an intermediate film between a phosphor layer of a phosphor screen and a metal back, and at least the phosphor layer contacting surface of the intermediate film is made of a polyvinyl alcohol-stilbazolium-based photosensitive material. It is characterized by being made of a synthetic resin.

The polyvinyl alcohol-stilbazolium-based photosensitive resin contains a photosensitive polyvinyl acetate saponified derivative represented by the following formula.

represents the main chain of the compound, m is an integer of 1 to 6, n represents O or 1, this part is a so-called photosensitive unit,
It is formed when two hydroxyl groups in a polyvinyl acetate molecule and an aldehyde undergo dehydration condensation to produce an acetal. The degree of saponification of this photosensitive saponified polyvinyl acetate derivative is 50 to 100%2 The degree of polymerization is 300 to 40
00 is desirable.

Moreover, in the above formula (1), Y is represented by the following general formula. The above formula (■) is a styrylpyridinium derivative, the above (I[[) formula is a styrylquinolinium derivative, R1 is a hydrogen atom, an unsubstituted alkyl group, an unsubstituted aralkyl group, a hydroxyl group, a carbamoyl group,
represents any one of an alkyl group or an aralkyl group having either an ether bond or an unsaturated bond, R2 represents either a hydrogen atom or a lower alkyl group, and
X- represents an anion, examples of which include chloride ion, bromide ion, sulfate ion, phosphate ion, perchlorate ion, methosulfate ion, p-toluenesulfonate ion, and fluoroborate ion.

The vinyl alcohol unit contained in the vinyl structural unit of the saponified polyvinyl acetate derivative substituted by the photosensitive unit is within the range of 0.1 to 50 mol%.

The photosensitive polyvinyl acetate saponified derivative having the photosensitive unit represented by the above formula (1) can be used as a protective colloid for a vinyl compound-based polymer resin, and can also be handled as an aqueous emulsion.

However, as it is, gelation easily occurs and it is difficult to handle water alone as a medium, so a hydrophobic unit represented by the following formula is further introduced into the main chain of the photosensitive saponified polyvinyl acetate derivative. However, it represents the vinyl alcohol residue in the main chain of the saponified derivative.

The above formula (IV) represents a hydrophobic unit having an acetal structure, and R3 is a hydrogen atom, an alkyl group, an allyl group, a phenyl group, a carboxyphenyl group, a sulfoxyphenyl group, an aminophenyl group, a nitrophenyl group, or a halogenated phenyl group. group, styryl group, tolyl group, benzyl group, xylyl group, naphthyl group, or anthryl group.

These can be produced by dehydrating and condensing aldehyde compounds such as butyraldehyde, octylaldehyde, heptylaldehyde, nonylaldehyde, benzaldehyde, naphthylaldehyde, aminobenzaldehyde, nitrobenzaldehyde, carboxybenzaldehyde, and sulfoxybenzaldehyde with the main chain of saponified polyvinyl acetate. Can be synthesized.

On the other hand, the above formulas (V) and (Vl) represent a hydrophobic unit having an acyl group, and Rn+R in the above formula (V)
s+Ra represents alkyls that are different from each other, including the case where one of them is a hydrogen atom, and the above formula (
R1 in VT) represents any one of an alkyl group, an allyl group, a propionyl group, a phenyl group, a halogenated phenyl group, a benzyl group, a styryl group, a xylyl group, a tolyl group, a benzoyl group, a naphthyl group, and an anthryl group. For example, it can be synthesized by an acylation reaction using chlorides such as acetyl chloride, propionyl chloride, and benzoyl chloride, or acid anhydrides such as acetic anhydride and benzoic anhydride.

The vinyl alcohol unit contained in the vinyl structural unit of the saponified polyvinyl acetate derivative substituted with the hydrophobic unit as described above is 0.1 to 30 mol %.

In this way, at least one photosensitive unit and at least one
When using a photosensitive saponified polyvinyl acetate derivative into which hydrophobic units have been introduced as a protective colloid for an aqueous emulsion of a vinyl compound polymer resin, examples of vinyl compound polymer resins that can be used include polyvinyl acetate, vinyl acetate, etc. -ethylene copolymer, vinyl acetate-acrylic acid copolymer, vinyl acetate-acrylic ester copolymer, polyacrylate, acrylic acid-acrylic ester copolymer, polystyrene, styrene-acrylic acid copolymer, styrene- Examples include acrylic acid ester copolymer, polyvinyl chloride, polyvinylidene chloride, vinyl acetate-methacrylic acid copolymer, vinyl acetate-methacrylic acid ester copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, etc. It will be done.

The solid weight ratio of the protective colloid to the vinyl compound polymer resin as described above is within the range of 5% to 99%.

Furthermore, it is also possible to use the above-mentioned aqueous emulsion as the first component and to mix therewith a second component that is an aqueous solution of a photosensitive resin. At this time, the degree of saponification of the photosensitive saponified polyvinyl acetate derivative contained in the second component and the content of photosensitive units and hydrophobic units are the same as in the case of the first component, but the degree of polymerization is 2500 or less. shall be.

Further, the weight ratio of the first component and the second component in terms of solid content is 100:1 to 10:1OO.

The polyvinyl alcohol-stilbazolium photosensitive resin described above is applied in the form of a slurry to the entire surface of a glass panel on which carbon stripes and a phosphor layer have been formed in advance, and then external exposure from the glass panel side or fluorescent coating is applied. It is photocured by exposing the inner surface from the body layer side to become a smoothing film.

When external exposure is performed, the carbon stripes act as a mask, so the light passes only through the phosphor layer, and the slurry is photocured only in the areas in contact with the phosphor layer, resulting in a partial smoothing film. is formed. On the other hand, when the inner surface is exposed, the slurry is photocured even in parts other than the phosphor layer, that is, in the parts in contact with the carbon stripes, and a smoothing film is formed over the entire surface.

Note that, if necessary, an intermediate film made of a hard acrylic resin may be provided on the smoothing film.

[Effect]

If a material with a large particle size is used as the phosphor particles dispersed in the phosphor layer, the surface of the phosphor layer after coating and curing of the phosphor slurry will have irregularities reflecting the shape of the particles. Even if an intermediate film was formed on top of this using a conventional photosensitive resin, a sufficient smoothing effect could not be obtained because a portion of the photosensitive resin penetrated into the phosphor layer. In contrast, in the present invention, a polyvinyl alcohol-stilbazolium-based photosensitive resin is applied onto the phosphor layer and photocured.

Since this photosensitive resin has lower permeability to the phosphor layer than conventional interlayer film materials, it remains on the surface of the phosphor layer and can effectively eliminate irregularities. If the surface of the phosphor layer is smoothed in this way, the surface of the interlayer film formed on it as needed will follow suit, and the surface of the metal back formed on it will also be mirror-like. It will be in good condition, close to it. Therefore, the reflectance increases, making it possible to increase the brightness of the cathode ray tube.

〔Example〕

Hereinafter, preferred embodiments in which the present invention is applied to a color cathode ray tube will be described with reference to the drawings.

The configuration of the phosphor screen of the color cathode ray tube according to this example is explained in the first example.
[! In this figure, shown in I, carbon stripes (2) are formed at predetermined intervals on the glass panel (1), and red, green, and blue colors are filled in between each carbon stripe (2). Phosphors N(3) in which any of the phosphor particles are dispersed are sequentially formed. The above phosphor N (3
) has some unevenness on its surface, but this is effectively eliminated by the smoothing film (4) formed thereon. Furthermore, a metal back (6) is laminated on the smoothing film (4) with an intermediate film (5) interposed therebetween.

Such a color cathode ray tube can be manufactured, for example, by the following steps.

First, a phosphor 15 (3) is applied onto a glass panel (1) on which a carbon stripe (2) has been formed in advance, for example, by the so-called external exposure method previously disclosed by the applicant in JP-A-60-119055. This external exposure method involves forming a resist layer using a photosensitive resin that can be reversed with a hydrogen peroxide solution, and a phosphor slurry in which a fluorescent dye is dispersed in a photosensitive resin that cannot be reversed with a hydrogen peroxide solution. This is a technique to create a phosphor screen by coating and curing in the following order. In addition, carbon stripe (
2) i of the carbon stripe (2) after forming
(A protective film (not shown) for preventing I separation may be formed over the entire surface.

Next, this glass panel (1) was heated to about 40°C using a far-infrared heater, and the rotation speed was 7 rpm.

A slurry of polyvinyl alcohol-stilbazolium photosensitive resin is applied at a revolution angle of 15'1.

Next, the excess slurry was shaken off at an autorotation speed of 120 rpm and a revolution angle of 105'', and the entire surface was dried by heating.

Next, external exposure is performed from the glass panel side at an exposure dose of 2 mW sec/cm". As a result, only the portion of the slurry that was not masked by the carbon stripe, that is, the upper part of the phosphor layer, is photocured. happen.

Next, this glass panel is subjected to water development, and the unhardened slurry is washed away with water. As a result, a smoothing film is formed only in the portion that is in contact with the phosphor layer.

Next, the water attached by water development is removed by shaking off, and the glass panel is further heated to about 40° C. and dried.

Next, acrylic resin was applied at an autorotation speed of 20 rpm and a revolution angle of 1051, and this was further applied at an autorotation speed of 120 rpm,
Shake off at a revolution angle of 105° and rapidly heat to dry.

Thereafter, a metal back is formed by vacuum evaporation of aluminum to complete the phosphor screen of the color cathode ray tube.

Here, this example will be explained in more detail based on an experimental example.

Experimental Example 1 According to the manufacturing process described above, the particle size was 12 to 13μ.
We prototyped a 13-inch beam index tube using large phosphor particles, and measured its brightness. The phosphor particles used were YzOs:Eu (red).

Y3A lsG a to+z: T b (green)
, ZnS:Ag.

It is Al2 (blue). In addition, as a polyvinyl alcohol-stilbazolium photosensitive resin for forming the smoothing film, CT-8 manufactured by Tamako Kako Co., Ltd. (concentration 50%, viscosity 5
0 cps), and B-74 Brimal manufactured by Nippon Acrylic Co., Ltd. was used as the acrylic resin for forming the interlayer film.

In order to conduct a comparative experiment at the same time, the screen of one glass panel was divided into two halves, and a smoothing film was formed on only half of the screen. To measure the brightness, set the DC cathode current (I,) to 1
00. 500, 1000, and 2000 llA were used for the three colors at the same time. The results are shown in Table 1.

Table 1 From the results, the brightness is approximately 20% when the smoothing film is provided.
It is clear that there has been an improvement.

It should be noted that an improvement in brightness was also observed when the intermediate film made of acrylic resin was not provided.

Experimental Example 2 An experiment similar to Experimental Example 1 described above was conducted using a commercially available 14-inch Trinitron tube. That is, the particle size is 5 to 1
A phosphor screen on which a phosphor layer was formed using general phosphor particles of 0 μm was obtained, and a smoothing film was formed according to the above-described process. Note that the phosphor particles used here are YzOtS:Eu (red) + ZnS:C
u, Al (green), and ZnS:Ag (blue). In addition, as a polyvinyl alcohol-stilbazolium photosensitive resin for forming a smoothing film, CT manufactured by Tamako Kako
-8 (IjA degree 50%, viscosity 50 cps), B manufactured by Nippon Acrylic Co., Ltd. is used as the acrylic resin for forming the interlayer film.
-74 Brimal was used. For comparison, a normal Trinitron tube without a smoothing film was also prepared.

Table 2 shows the results of measuring the brightness of each of these Trinitron tubes for each of the three colors.

Table 2 From this result, when a smoothing film is provided, the brightness is approximately 6 to 1
It is clear that the improvement was 0%.

In addition, in the case of this Trinitron tube, unlike the case of the beam index tube described above, when the slurry of polyvinyl alcohol-stilbazolium-based photosensitive resin is applied onto the phosphor layer, the slurry is repelled and uneven coating occurs. Therefore, an interlayer film made of acrylic resin is required.

〔Effect of the invention〕

As is clear from the above description, in the cathode ray tube according to the present invention, a smoothing film made of a polyvinyl alcohol-stilbazolium photosensitive resin is formed in the portion where the conventional intermediate film was in contact with the phosphor. This effectively eliminates unevenness on the surface of the phosphor layer even when materials with large particle diameters are used as the phosphor particles, making it possible to finish the surface of the metal back to a near-mirror finish. Therefore, the reflectance of the metal back is improved, making it possible to provide a high-luminance cathode tube.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a phosphor screen of a color cathode ray tube to which the present invention is applied. FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a phosphor screen of a conventional color cathode ray tube. l... Glass panel 2... Carbon stripe 3... Phosphor layer 4... Smoothing film 5... Intermediate film 6... Metal back Patent applicant Sony Corporation representative Patent attorney Koike Viewing by Sakae Tamura and Masaru Sato Figure 2

Claims (1)

[Scope of Claims] A cathode ray tube having an intermediate film between a phosphor layer of a phosphor screen and a metal back, wherein at least the phosphor layer contacting surface of the intermediate film is a cathode ray tube made of a polyvinyl alcohol-stilbazolium based photosensitive resin. tube.