JP2514544B2 - Monochrome phosphor paste composition and phosphor surface using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a phosphor paste for printing, which can form a uniform and high-resolution phosphor film surface necessary for forming a monochrome phosphor surface of a cathode ray tube (hereinafter abbreviated as CRT), and the same Regarding the phosphor surface.

[0002]

2. Description of the Related Art CRT represented by a cathode ray tube of a television
Is a display device in which an electron beam emitted from an electron gun collides with a phosphor surface and phosphor particles are excited to display light.
With the development of electronics in recent years, various visual devices using CRTs have been diversified, and various types such as color CRTs, monochrome CRTs, large CRTs, and ultra-compact CRTs have been produced.

[0003]

A CRT used for such a visual device has no pinhole and the most important part for exhibiting good light emission characteristics is a method for manufacturing a phosphor film surface. As a method of manufacturing the body membrane surface,
Slurry method, sedimentation method, electrodeposition method, vapor deposition method, photoetching method and the like are known. For example, a sedimentation method has been generally used for a phosphor film surface used in a high resolution cathode ray tube for a monochrome monitor.

However, it is difficult to efficiently obtain a phosphor film surface having a uniform thickness with less unevenness on the phosphor film surface formed by this method.

Therefore, recently, it has a uniform phosphor film thickness,
A printing method has come to be used as a method for forming a phosphor film of a high-resolution CRT with less unevenness on the surface of the phosphor film. This printing method is characterized in that a phosphor paste is printed directly or indirectly on a CRT panel (front glass), and then the binder resin component in the paste is baked and removed to form a phosphor film surface. There is. Further, it is an industrially advantageous method because the facility cost is lower than the conventional method, the recovery loss of the phosphor particles is small, the material cost can be reduced, and the productivity is high.

A method of manufacturing a CRT using this method is disclosed in Japanese Examined Patent Publication No. 61-23231 and Japanese Unexamined Patent Publication No. 59-213.
Japanese Patent No. 778 has been proposed.

However, the average volume particle diameter of the phosphor particles contained in the phosphor paste conventionally used in the phosphor film surface forming method by the printing method is 10 μm, and at least 5 μm or more. Since the phosphor film formed from the phosphor paste has a large phosphor particle size, when used in a high-resolution CRT, surface irregularities are conspicuous, and thus high resolution cannot be obtained.

In order to improve the resolution of the CRT phosphor film, a method of crushing the above-mentioned phosphor particles having a large particle diameter to prepare a phosphor paste has been proposed. When formed into a paste from the shape, there was a strong tendency to easily agglomerate and poor dispersibility.

That is, an aggregated fluorescent portion is formed in a phosphor film formed by a printing method using a paste containing an aggregate of printed phosphor particles, and the aggregate portion is abnormal when used as a CRT. It becomes a light emitting portion and appears on the surface, resulting in a decrease in resolution, which is a defect of a CRT.

Further, the phosphor particles are usually those whose surface is coated with an activator, and those obtained by simply crushing such phosphor particles are the parts where the surface of the phosphor particles is not coated with the activator. As a result, the light emission characteristics are inevitably deteriorated as compared with uncrushed phosphor particles, and when the brightness of a CRT made using a paste containing such phosphor particles is increased to a practical range. The acceleration voltage of the electron gun used,
It is necessary to increase the operating current and the like, and not only a great load is applied to the electronic circuit, but also an unfavorable result such as high cost is brought about.

[0011]

SUMMARY OF THE INVENTION The present invention is a CR for high resolution.
The present invention relates to a phosphor paste, which is most important in the production of T, and which provides a phosphor surface having few irregularities on the phosphor film and having high luminous efficiency, and a phosphor surface using the same.

That is, the gist of the present invention is that in a cathode ray tube phosphor screen printing paste comprising phosphor particles, a binder resin and a solvent, the phosphor particles are substantially coated with an activator, A phosphor paste composition in which particles having an average volume particle diameter of 1 to 4 μm and a particle diameter of 1 to 6 μm are contained in phosphor particles in an amount of 60% or more and a phosphor surface using the phosphor paste composition have high resolution and high resolution. It is possible to manufacture a CRT having luminous efficiency.

The surface of the phosphor particles used in the present invention is substantially coated with an activator, and the average volume particle size is 1
Particles having a particle size of ˜4 μm and a particle size of 1 to 6 μm are contained in the phosphor particles in an amount of 60% or more.

In the present invention, it is necessary that the surface of the phosphor particles is substantially coated with an activator, and phosphor particles having a large particle size are simply crushed to reduce the particle size. The number of phosphor particles on the surface of which the phosphor particles are not coated with the activator increases, and the phosphor film formed by using the paste containing such phosphor particles deteriorates the light emission characteristics, which is not preferable.

The phosphor particles used for forming the phosphor surface for a monochrome cathode ray tube preferably have an average volume particle diameter of 1 to 4 μm, and it is difficult to manufacture phosphor particles having an average volume particle diameter of less than 1 μm, resulting in high cost. Also, the phosphor particles once dispersed in the binder resin are likely to re-aggregate, and the brightness of the phosphor film formed from such a phosphor paste is lowered, which is not preferable. Also, the average volume particle size is 4 μm.
CRT obtained from a paste containing phosphor particles exceeding 1
It is not preferable because pinholes are generated in the phosphor film, and the smoothness of the phosphor film surface is poor and the resolution is lowered.

It is preferable that the phosphor particles contain 60% or more, preferably 80% or more of phosphor particles having a particle diameter of 1 to 6 μm, and a paste containing phosphor particles having a wider particle size distribution. The resulting phosphor film is not preferable because pinholes, lack of smoothness, agglomeration of phosphor particles and the like occur.

The phosphor particles and activator used in the present invention are not particularly limited, and may be arbitrarily selected from generally known ones such as monochrome and color, depending on the purpose. Also, the description of the phosphor particles and the activator is described in JEDE.
It uses C based RMA numbers.

The binder resin used in the present invention is not particularly limited as long as it has a good baking property and can uniformly disperse the phosphor particles, and it can be arbitrarily selected according to the purpose. Good.

Specific examples of the binder resin include known ones such as cellulose-based resins, vinyl alcohol-based resins and acrylic resins.

The solvent used in the present invention may be any solvent as long as it can prevent the paste composition from changing over time, and may be arbitrarily selected according to the kind and purpose of the binder resin. For example, diethylene glycol monoethyl ether acetate. , Diethylene glycol monobutyl ether acetate, 2,2,4-trimethyl 1,3-pentadiol monoisobutyrate, isophorone, 3-methoxybutyl acetate and the like.

In the present invention, the compounding ratio of the phosphor particles and the binder resin is not particularly limited and can be arbitrarily selected according to the purpose, but usually, phosphor particles / binder resin = 100 g / 5 g-100 / 40 g, preferably about 100 g / 10 g to 100 g / 30 g.

Further, the solvent is used for adjusting the viscosity of the paste composition, and the compounding amount may be arbitrarily compounded so as to obtain the desired viscosity of the phosphor paste composition. Usually, the viscosity of the phosphor paste composition is 5,000 to 200,000.
It is about 0 centipoise and may be set according to the purpose.

In the present invention, various additives such as generally known plasticizers, dispersion stabilizers, leveling agents, and thixotropy imparting agents are added depending on the purpose, as long as the objects of the present invention are not impaired. be able to.

[0024]

EXAMPLES The present invention will be described in detail below with reference to examples. In the examples, parts and% represent parts by weight and% by weight, respectively.

<Example 1> Isobutyl methacrylate 9
8 parts, 2 parts of methacrylic acid and 1.5 parts of azobisisobutyronitrile were reacted in diethylene glycol monoethyl ether acetate at 80 ° C. for 10 hours.

Monochrome phosphor particles P-4 were added to a resin solution containing 100 parts of the obtained acrylic resin as a binder resin.
5 fine powder (yttrium oxysulfide (Y ₂ O ₂ S) coated with terbium as an activator), average volume particle diameter 3.0 μm, and content exceeding 6 μm particle diameter 5%
450 parts Disperse and knead the entire phosphor particles, and adjust the viscosity to 1 with diethylene glycol monoethyl ether acetate.
A monochrome phosphor paste composition adjusted to 3,000 cps (25 ° C.) was prepared.

The composition was applied on a glass plate to a thickness of 20 μm by a screen printing method, and dried and baked.

When the state of the phosphor film surface was evaluated using both transmitted light and reflected light using an optical microscope of 50 to 400 times, no pinhole was observed on the obtained phosphor film surface. The phosphor had a good hiding property, a smooth phosphor surface was formed, and the light emitting property was also good. Also, the 1.5-inch monochrome CRT made using this glass plate is 600
It had more than one scanning line.

<Examples 2 and 3 and Comparative Examples 1 and 2> Four kinds of phosphor pastes were prepared in the same manner as in Example 1 except that four kinds of phosphor particle diameters shown in Table 1 were used. , Using this, in the same manner as in Example 1, to make four types of phosphor film surfaces,
The state was evaluated.

The results obtained are shown in Table 1.

[Table 1]

<Comparative Examples 3 to 6> In the same manner as in Example 1 except that phosphor particles having an average volume particle size of 8 μm are simply crushed into phosphors having an average volume particle size as shown in Table 2. 4 types of phosphor pastes were prepared by using the same, and the states of the 4 types of phosphor film surfaces prepared in the same manner as in Example 1 were evaluated.

The obtained results are shown in Table 2.

[Table 2]

As is clear from the results shown in Table 2, the phosphor film surface made by using the phosphors in which the phosphor particles are simply crushed to adjust the average volume particle diameter is the average volume particle of the phosphor particles. Even when the diameter was in agreement with the average volume particle diameter within the range of the present invention, the light emitting property was inferior, and the phosphor film state was almost the same as that of the unpulverized particle diameter.

<Examples 4 to 7, Comparative Example 7> Phosphor particles having an average volume particle diameter and a particle size distribution as shown in Table 3 were coated with an activator in the same manner as in Example 1. Five types of phosphor pastes were prepared in the same manner as in Example 1 except that body particles were used, and the state of the phosphor film surface prepared in the same manner as in Example 1 was evaluated using these phosphor pastes.

The results are shown in Table-3.

[Table 3]

Phosphor film pinhole: The phosphor paste composition is printed on a glass plate, dried and baked, and the phosphor film surface is pinhole-shaped by using transmitted light with an optical microscope of 50 to 400 times. Existence was checked. ⊚: No pinholes were observed ○: Almost no pinholes were observed △: Some pinholes were observed ×: Pinholes were considerably observed

Smoothness: The phosphor paste composition is printed on a glass plate, dried and fired to give a phosphor film surface of 50 to 400.
Visual evaluation was performed using reflected light with a 2 × optical microscope. ◎: Very small irregularities, no screen mesh traces ○: Small irregularities, no screen mesh traces Δ: Large irregularities ×: Very large irregularities, screen mesh traces

Aggregate: The phosphor paste composition was printed on a glass plate, dried and baked, and the phosphor film surface was evaluated with a 50 × optical microscope. ○: No fluorescent substance aggregates of 30 μm or more △: 〃 〃 Slightly present ×; 〃 〃 Very large

Luminescent property: CRT using phosphor particles which were not crushed was evaluated as a standard. ○: Equal to the case of non-crushed phosphor particles ×: Inferior to 〃 〃

As described in detail above, since the phosphor paste composition of the present invention uses phosphor particles having a specific particle size and a specific particle size distribution, a phosphor film is prepared using this. The obtained CRT has few irregularities on the phosphor surface, no pinholes are generated, and it has excellent emission characteristics.
The phosphor paste composition for high resolution CRT and the phosphor surface using the same exhibit a very large effect.

Claims (2)

(57) [Claims] 1. A cathode ray tube phosphor film surface printing paste comprising phosphor particles, a binder resin and a solvent, wherein the phosphor particles are substantially coated with an activator and have an average volume particle diameter of 1 A monochrome phosphor paste composition, characterized in that the phosphor particles contain 60% or more of particles having a particle size of ˜4 μm and a particle size of 1 to 6 μm. 2. The content of phosphor particles having an average volume particle diameter of 1 to 4 μm and a particle diameter of 1 to 6 μm in all phosphor particles is 6.
A monochrome phosphor surface having a phosphor surface of 0% or more, and a phosphor surface formed of a fired body of phosphor particles substantially coated with an activator.