JPH0342318B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a composition used in forming a color picture tube fluorescent film and a method for forming a fluorescent film using the same, and particularly to a composition used in forming a color picture tube fluorescent film, and in particular to a composition for forming a fluorescent film for a CaS-based fluorescent film. The present invention relates to a composition using the method and a method for forming a fluorescent surface.

[Technical background of the invention]

In general, the fluorescent surface of a shadow mask type color picture tube is usually formed by the following method. That is, a photosensitive phosphor aqueous suspension (hereinafter referred to as slurry) in which polyvinyl alcohol (PVA), ammonium dichromate (ADC), and phosphor powder are dispersed in an aqueous medium is applied to the inner surface of the face plate panel of the picture tube. is applied and irradiated with ultraviolet rays through a shadow mask having a desired pattern to insolubilize the irradiated portions, and then the unirradiated portions are washed away with water to obtain a dot-like or stripe-like phosphor pattern. By repeating this operation for each of the three color phosphors of green, blue, and red, a phosphor film for a color picture tube is obtained.

[Problems with background technology]

It has been desired to develop a material with good luminous efficiency as a material for such a phosphor film for picture tubes, and a yttrium-based phosphor has been developed as a high-brightness material, but this material is expensive and Ta.

On the other hand, attention has been paid to the fact that CaS is an inexpensive and high-luminance phosphor, and its application to the phosphor film of picture tubes is being considered.

However, when the above-mentioned PVA-ADC photoreceptor slurry is prepared by adding this CaS-based phosphor, this slurry gels in about 10 minutes after preparation, so the slurry is not applied to the inner surface of the face plate panel. The coating method (slurry method) cannot be applied. That is, in the slurry method, it is practically impossible to use a CaS-based phosphor as a phosphor for a picture tube. Moreover, since this method uses harmful chemicals such as ADC, there was a risk of causing pollution.

Recently, as a countermeasure to this problem, a method (powder method) has been proposed in which a material with appropriate adhesiveness and adhesive properties is applied to the inner surface of the face plate panel in advance, and then a phosphor is attached thereto in the form of a dry powder. (Refer to the specification of JP-A-56-41642).

However, even with this method, it is difficult to attach a sufficient amount of phosphor to the inner surface of the face plate panel.

[Purpose of the invention]

The present invention was developed to solve the problems in the slurry method described above, and uses a CaS-based phosphor that has high brightness, is stable without gelation, and has sufficient sensitivity. The object of the present invention is to provide a composition suitable for forming a fluorescent film and a method for forming a fluorescent film using the same.

[Summary of the invention]

The composition for forming a picture tube fluorescent film of the present invention contains a photosensitive resin made by introducing a stilbazolium group into polyvinyl alcohol and a CaS-based phosphor powder whose surface is appropriately coated with an organic resin film. Features.

That is, the composition of the present invention has at least the following formula: (In the formula, R represents a hydrogen atom, an alkyl group or a lower hydroxyalkyl group, and X ^- represents a strong acid anion.) A photosensitive resin containing repeating units (1) and (2) represented by; CaS-based phosphor powder whose surface is coated with an organic resin film is dispersed in an aqueous medium.

Further, the method for forming a fluorescent film on a picture tube according to the present invention is characterized in that it is a slurry method.

That is, in the method of the present invention, the composition for forming a fluorescent film in a picture tube is applied to the inner surface of the face plate panel of a picture tube, exposed to light in a desired pattern using a mask, developed, and then baked. This method is characterized by forming a fluorescent film in a desired pattern.

First, the photosensitive resin that is one component of the composition of the present invention will be explained.

The photosensitive resin used in the present invention is a resin containing repeating units represented by the above formulas (1) and (2) as essential components.

R in formula (1) can be selected from a hydrogen atom, an alkyl group, or a lower hydroxyalkyl group, specifically a hydrogen atom or a carbon atom having 1 to 3 carbon atoms.
Examples include an alkyl group or a hydroxyalkyl group. In addition, as X ^- , halogen ion,
Examples include sulfate ion, phosphate ion, and p-toluenesulfonate ion.

The proportion of this repeating unit (1) in the photosensitive resin is preferably in the range of 0.5 to 10 mol %, with the remainder mainly consisting of repeating unit (2). If the proportion exceeds 10 mol%, the water solubility of the resin will decrease, preventing the formation of a uniform slurry, and furthermore, in the baking process after development, a residue of the photosensitive resin will be produced in the fluorescent film, causing the fluorescent film to deteriorate. Unfavorable due to its characteristics. In addition, the proportion of the component of repeating unit (1) is 0.5mol
%, sufficient photosensitivity cannot be obtained, the sensitivity decreases, and it is not suitable for practical use.

In the present invention, the photosensitive resin has a polymerization degree of
400 to 3000 is preferred. In addition to the repeating unit component represented by the above chemical formula, the photosensitive resin of the present invention may also contain a copolymerizable vinyl monomer component to improve properties such as water solubility and thermal decomposition. You can also do that. Examples of the vinyl monomer in this case include vinyl acetate, vinyl propionate, olefin, styrene, acrylic acid, acrylic ester, and derivatives thereof.

The photosensitive resin of the present invention described above can be produced by reacting partially saponified polyvinyl alcohol polyvinyl acetate or a copolymer thereof with a styrylpyridinium salt having a formyl group. The manufacturing method is
This is known from Japanese Patent No. 56-5761.

Next, the CaS-based phosphor powder coated with an organic resin film, which is another component of the composition of the present invention, will be explained.

First, the CaS-based phosphor powder according to the present invention is
CaS is activated with cerium, europium, silver, etc. This phosphor powder has a particle size of 4~
Preferably, it is 15 μm.

Examples of the organic resin film coated on the surface of the CaS-based phosphor powder include a film made of a polymer compound with good film-forming ability, such as nitrocellulose or acrylic resin. The coating weight of this film is preferably in the range of 0.001 to 4.0% based on the CaS-based phosphor powder. If it is less than 0.001%, the photosensitive physical properties of the composition of the present invention will deteriorate, and if it exceeds 4.0%, the luminance of the phosphor will decrease significantly, which is not preferable.

In order to form an organic resin film on the surface of the CaS-based phosphor powder, for example, a predetermined amount of the above-mentioned polymer compound is dissolved in an appropriate organic solvent, and the phosphor is dispersed in the resulting solution. This is carried out by supporting a predetermined amount of a polymer compound on the surface of this phosphor, and then fractionating it and evaporating it to dryness.

The aqueous medium used in the present invention is water or a mixture of water and a polar organic solvent. Among these, it is preferable to use the latter mixture from the viewpoint of increasing the solubility of the photosensitive resin. Examples of such organic solvents include alcohol, dimethylformamide, formamide, and dimethylsulfoxide.

The composition of the present invention can be obtained as a slurry by dispersing the above-described photosensitive resin and CaS-based phosphor powder whose surface is coated with an organic resin film in a predetermined mixing ratio in an aqueous medium. At this time, the photosensitive resin is preferably blended in a proportion of 1.5 to 4.0% by weight based on the total amount of the slurry. If this ratio exceeds the above range, the viscosity of the slurry will increase, making coating work difficult, and if it falls below the above range, the photosensitivity of the slurry will decrease and the exposure pattern after development will become unclear. . Further, the phosphor powder whose surface is coated with an organic resin film is preferably blended in an amount of 10 to 40% by weight based on the total amount of the slurry. If the mixing ratio exceeds the above range, the phosphor powder will settle in the slurry, and if it falls below the above range, the amount of phosphor coated on the panel face plate will decrease. In addition, if the obtained slurry is unstable and tends to produce sediment, it can be stabilized by adding a surfactant. Further, known additives such as thickeners and repellering agents can also be used in combination. The slurry of the present invention preferably has a viscosity in the range of 15 to 30 cps (21°C) from the viewpoint of ease of coating work.

Next, the fluorescent film forming method of the present invention will be explained.

A slurry having the above-mentioned composition is prepared, applied to the inner surface of the face plate panel of the picture tube, and dried. Next, the photosensitive resin on the surface of the coating film is made insoluble in water by exposing it to ultraviolet light in a desired pattern using a shadow mask. Any light source can be used for the ultraviolet exposure as long as it contains an ultraviolet component having a wavelength around 340 nm, such as a high-pressure mercury lamp. Illuminance during exposure is 0.5~
An irradiation time of 2 to 60 seconds is sufficient at 2.0 mW/cm ² .
The pattern-exposed coating film is then developed to remove the photoreceptor composition in the non-irradiated areas. This development process is performed by washing with water or hot water.

Then, if necessary, the surface of the fluorescent film is subjected to so-called metal backing treatment with aluminum or the like. This step can compensate for the insufficient amount of light emitted from the fluorescent surface. This metal backing treatment is carried out by depositing a metal such as aluminum on the surface of the fluorescent film, but it is preferable to form an organic film on the surface of the fluorescent film by lacquering prior to the metal backing treatment. . The picture tube is then fired and printed onto the phosphor faceplate panel. Through this firing step, components other than the fluorescent material are removed by volatilization or thermal decomposition. On this occasion,
The firing temperature is preferably 350 to 450°C and the firing time is preferably in the range of 30 to 90 minutes. If the firing temperature is lower than this or the firing time is short, components such as resin will not be sufficiently removed and will remain as a residue, which will have an adverse effect on luminescence.

Through the above steps, a CaS-based fluorescent film can be formed on the face plate panel surface of the picture tube.

In order to manufacture a color picture tube, it is necessary to form phosphor layers of two other colors before and after the formation of this CaS-based phosphor film, but the formation of these phosphor layers is The order is arbitrary as long as it is before the metal backing process. Furthermore, as the photosensitive material used in forming the phosphor, the photosensitive resin of the present invention can be used, and further conventional PVA-ADC materials and the like can also be used.

[Embodiments of the invention]

Green-emitting phosphor CaS made by activating CaS with Ce:
Ce powder (particle size: about 7.0 μm) was washed with ethanol, filtered, and dried at about 80°C. Then, the following composition: Acrylic resin (manufactured by Rohm and Hass, B-
72) 1.4 parts by weight acrylic resin (manufactured by Du Pont, Lucite)
2045) 100 parts by weight of the CaS:Ce phosphor powder was added to a solution consisting of 2.2 parts by weight of toluene, 64 parts by weight and 32.4 parts by weight of ethyl acetate, and the mixture was stirred for about 15 minutes to form a suspension.
The suspension was filtered with suction, and the filtered material was allowed to stand for about 15 minutes while the suction was continued. 80~
It was dried at 100°C for about 1 hour. The resulting powder was sieved through a 500 mesh sieve to obtain a CaS:Ce green phosphor powder coated with 0.36% by weight of acrylic resin and having a particle size of approximately 7.0 μm.

Next, polyvinyl-α-methyl (γ-formylstyryl) pyridinium methosulfate (containing 1 mol% of the repeating unit represented by formula (1), with a polymerization degree of 2000) was used as the CaS:Ce green phosphor powder and photosensitive resin. ) using the following composition: CaS:Ce green phosphor powder 30 parts by weight Polyvinyl α-methyl (γ-formylstyryl) pyridinium methosulfate 2.1 parts by weight Surfactant (Nonion LT-221, NOF Corporation)
A slurry containing approximately 68 parts by weight of pure water and 0.1 part by weight of pure water was prepared. The viscosity is 23.5 cps (21
℃). Apply this slurry to the face plate panel, dry it, and apply it through a shadow mask.
After irradiating the green phosphor pattern formation position with an illuminance of 1.5 mW/cm ² for 5 seconds using an exposure table using an ultra-high pressure mercury lamp as the light source, hot water development was performed to form a CaS phosphor layer. Next, the blue phosphor and red phosphor were added to the conventional
Repeat the same process using ADC/PVA resist.
Each phosphor layer was formed. Next, after forming an organic film by the so-called lacquer method, an aluminum metal pack was formed, and then heated at 430℃ for 30 minutes.
A color picture tube A was manufactured by firing for 1 minute.

Next, in order to compare the slurries, a color picture tube B was manufactured in the same manner as above except that CaS:Ce green phosphor powder whose surface was not coated with an organic resin film was used.

Regarding the above color picture tubes A and B, the change in relative photosensitivity over time after slurry preparation was measured. Photosensitivity is measured by coating a face plate panel with slurry and drying it to form a photoresist film, then exposing it to a certain amount of light, and comparing the pattern size and adhesion state of the phosphor layer obtained after development. Ta. The measurement results are shown in the figure. Note that the photosensitivity immediately after slurry preparation is 100.

Next, in order to compare the slurry and the fluorescent film forming method, a color picture tube was manufactured by a powder method using a conventional slurry.

That is, first, the following composition: Dimethylaminobenzenediazonium chloride Zinc chloride 3 parts by weight Alginic acid propylene glycol ester
After applying a sticky solution consisting of the remaining amount of 0.6〃 ethylene glycol and 0.2〃 water to the panel and drying it,
Through a shadow mask, the green phosphor pattern formation position is illuminated with an exposure table using an ultra-high pressure mercury lamp as a light source.
Irradiation was performed for 2 seconds at 1.5 mw/cm ² . Next, CaS:Ce green phosphor powder was sprinkled on the inner surface of the panel, the phosphor was adhered to the desired pattern, and the excess phosphor was removed using air spray. Next, the blue phosphor layer and the red phosphor layer were repeated in the same manner using conventional ADC-PVA resists to form respective phosphor layers.

A color picture tube C was manufactured in the same manner as the method of the present invention.

For picture tubes A and C, white brightness (9300K+
The total cathode current required to make the white color of 27MPCD brighter than 32L = W _Ib ) was measured. As a result, the brightness of picture tube A was 100 μA, and the brightness of picture tube C was 111 μA. Therefore, according to the present invention, it was found that the brightness was improved by 10%.

〔Effect of the invention〕

According to the composition (slurry) of the present invention, it is possible to form a fluorescent film that is stable and has good sensitivity without the risk of gelation after the slurry is prepared. Furthermore, according to the method of the present invention using this composition, a high-brightness CaS-based phosphor can be formed uniformly and in a sufficient amount on the face plate panel surface in the form of a stable aqueous slurry, which improves luminous efficiency. It is possible to manufacture picture tubes with good quality through a simple process, and
Pollution prevention measures are also advantageous because there is no need to use harmful chemicals such as ADC.

[Brief explanation of drawings]

The drawing shows the relative photosensitivity of color picture tubes A and B together with changes over time after slurry preparation.

Claims (1)

[Claims] 1. At least the following formula: (In the formula, R represents a hydrogen atom, an alkyl group or a lower hydroxyalkyl group, and X ^- represents a strong acid anion.) A photosensitive resin containing repeating units (1) and (2) represented by; 1. A composition for forming a picture tube fluorescent film, comprising: a CaS-based phosphor powder whose surface is coated with an organic resin film; and dispersed in an aqueous medium. 2. The composition for forming a picture tube fluorescent film according to claim 1, wherein the photosensitive resin contains 0.5 to 10 mol% of the repeating unit represented by the formula (1). 3. The composition for forming a picture tube fluorescent film according to claim 1, wherein the coating weight of the organic resin film is 0.001 to 4.0% based on the CaS-based phosphor powder. 4 At least the following formula: (In the formula, R represents a hydrogen atom, an alkyl group or a lower hydroxyalkyl group, and X ^- represents a strong acid anion.) A photosensitive resin containing repeating units (1) and (2) represented by; A composition for forming a picture tube fluorescent film, which is made by dispersing CaS-based phosphor powder whose surface is coated with an organic resin film in an aqueous medium, is applied to the inner surface of the face plate panel of the picture tube, and a mask is applied. 1. A method for forming a fluorescent film on a picture tube, which comprises exposing the film to light in a desired pattern, developing and then baking to form a fluorescent film in a desired pattern.