JP2543737B2 - Color television fluorescent - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a phosphor used in a cathode ray tube for a color television, and more particularly to a phosphor for a color cathode ray tube in which a phosphor film is formed by a slurry coating method.

[Prior art and its problems]

Generally, a slurry coating method is adopted for forming a fluorescent film of a color television. This slurry coating method is
Optical printing technology is used. In this method, first, phosphor particles are dispersed in a photosensitive resin solution containing, for example, polyvinyl alcohol (PVA) and ammonium dichromate. The photosensitive resin solution in which the phosphor particles are dispersed is called a phosphor slurry solution. This phosphor slurry solution is uniformly applied to the inner surface of the glass panel, and then exposed and developed by a well-known optical printing technique to form regularly arranged stripes or dots of a desired shape on the inner surface of the glass panel. To be done. Then, these steps are repeated for each of the blue, green and red phosphors to form the phosphor film. For the phosphor used in such a slurry coating method, good dispersibility in the phosphor slurry solution is particularly important. That is, when the dispersibility of the phosphor is poor, the end shape of the stripes or dots becomes poor, the phosphor film cannot be formed uniformly or densely, and the properties of the phosphor film deteriorate. Further, depending on the dispersibility of the phosphor, the exposure sensitivity of the slurry solution is lowered, and the workability in forming the phosphor film is lowered. Therefore, conventionally, silicon dioxide,
Silicon compounds such as zinc silicate and aluminum silicate are attached to improve dispersibility. A technique for adhering silicon dioxide, an aluminum compound and a zinc compound having a specific particle size on the surface of phosphor particles has been developed (Japanese Patent Publication No. 61-46512).
Issue). However, when a high-definition color cathode-ray tube is manufactured with conventional phosphors to which these substances are adhered, good dispersibility is not obtained in any of them, and it is uniform and dense and has excellent edge formation. It is difficult to obtain a high definition fluorescent film. That is, the stripe or the fluorescent film of the high-definition color cathode-ray tube that needs to have a small dot shape attaches the phosphor very finely, for example, in a dot shape so that the dot pitch is 0.4 mm or less. Although necessary, a phosphor having insufficient dispersibility cannot accurately attach fine dots with a clean contour.

[Problems to be Solved by the Invention]

The present invention has been made in view of the above circumstances, and an object thereof is to have an extremely excellent dispersibility, and to provide a uniform and dense fluorescent film at the time of forming a fluorescent film of a color cathode ray tube. Another object of the present invention is to provide a phosphor for television that can be well formed.

[Means for solving problems]

In order to achieve the above-mentioned object, the phosphor of the present invention has a divalent or tetravalent structure in addition to silicate on the surface of the phosphor particles.
Valuable tin compound is attached. The amount of tin contained in the tin compound is adjusted to 0.001 to 0.5 part by weight or less based on 100 parts by weight of the phosphor, and the amount of silicate attached is adjusted to 2 parts by weight or less. The reason why the amount of tin contained in the tin compound is set within the above range is that the dispersibility of the phosphor decreases if the amount of tin is too large or too small as shown in FIG. As the divalent or tetravalent tin compound, tin hydroxide, stannic acid, or organic tin can be preferably used. As the silicate, preferably, zinc silicate, aluminum silicate, magnesium silicate or the like is used alone, or a plurality of these are mixed and used.

[Action]

A divalent or tetravalent tin compound, such as stannic acid, is a tin (IV) oxide hydrate (SnO ₂ · nH ₂ O).
The hydrate adsorbed alkali is a colloidal solution and does not have a constant composition. This stannic acid, in addition to silicate, the phosphor particles of the present invention adhered to the surface, after drying,
The surface of the phosphor particles becomes smooth, and
When the phosphor particles are suspended in the phosphor slurry solution in the slurry coating method, the dispersibility is extremely good for forming the phosphor film. Similarly, tin hydroxide “Sn (OH) ₂ ” is also easy to form a colloid and does not have a constant composition, but the phosphor particles in which tin hydroxide is added to the silicate and adhered to the surface are When the phosphor particles are suspended in the phosphor slurry solution, the dispersibility is extremely good for forming the phosphor film.The phosphor of the present invention has a divalent or tetravalent tin compound attached in addition to the silicate. However, this phosphor exhibits an excellent dispersibility that cannot be realized by a phosphor having a silicate alone attached to the surface or a tin compound alone attached to the surface. Phosphor is silicate and 2
It is considered that the phosphor causes a repulsion due to an electric value due to the fact that both the tin or tetravalent tin compound is attached to the surface. Needless to say, even if tin hydroxide, organic tin or stannic acid is attached to the surface of the phosphor particles, good dispersibility is exhibited.

[Preferred embodiment]

Hereinafter, prior to the examples of the present invention, 2
A method of depositing a tin or tetravalent tin compound will be described. The divalent or tetravalent tin compound used in the present invention, that is, tin oxide or tin hydroxide, is SnCl ₄ , Sn (SO ₄ ) ₂ , Sn (N
A hydrolyzed tin salt such as O) ₄ can be used, and Sn (CH—COO) ₄ , Sn (C—O) _4, etc. can be used as the organic tin. That is, in the method of obtaining tin hydroxide by hydrolyzing a tin salt, first, the phosphor particles to be adhered are suspended in water, and a tin salt aqueous solution, for example, SnCl ₄ aqueous solution is added in a predetermined amount. While the phosphor suspension to which the SnCl ₄ aqueous solution has been added is not stirred, it is hydrolyzed by adjusting the pH to 6 to 8 with an alkali such as aqueous ammonia or sodium hydroxide. As a result, the divalent tin compound, namely,
Tin hydroxide [Sn (OH) ₂ ] is deposited. Except for adding an aqueous solution of tin organic acid salt, by performing the same method as described above, the surface of the phosphor particles,
A divalent or tetravalent tin compound is deposited, ie tin oxide and / or tin hydroxide. Drying is performed at a temperature of less than 100 ° C. to adsorb tin hydroxide or organic tin on the phosphor surface. Hereinafter, embodiments of the present invention will be described.

Example 1 After suspending 100 g of silver activated zinc sulfide phosphor in 250 ml of pure water, 2.5 ml of SnCl ₄ aqueous solution (Sn 2% content solution) was added to this phosphor suspension and stirred for 5 minutes. did. 5% NaOH aqueous solution was added dropwise with stirring to adjust the pH to 6.5,
The stirring was stopped and the phosphor particles were allowed to settle. After that, filtration
After drying (90 ° C. for 3 hours) and passing through a 300-mesh sieve, a phosphor having a tin compound, that is, tin hydroxide, attached to the surface of the phosphor particles was obtained. Next, 100 g of silver-activated zinc sulfide phosphor having tin hydroxide on the surface was suspended in 250 ml of pure water, and K ₂ SiO ₃ (2% of SiO ₂ was added to this phosphor suspension. (Containing solution) is added with stirring (1 ml), and 0.5 ml of ZnSO ₄ (solution containing 2% Zn) is further added and stirred. 2% N while stirring
Aqueous aOH solution is added dropwise to adjust the pH to 6.8. After 30 minutes,
Add 2.5 ml of SnCl ₄ (solution containing 2% Sn) and mix,
% NaOH aqueous solution was added dropwise to adjust the pH to 6.5 to precipitate phosphor particles. Then, it was separated by filtration, dried (at 90 ° C. for 10 hours), and passed through a 300-mesh sieve to obtain a phosphor in which tin hydroxide and zinc silicate were attached to the surface of the phosphor particles. The same silver as in Example 1 except that the obtained tin hydroxide-adhered phosphor was used to form stripes by the following ordinary slurry coating method, and only zinc silicate was adhered without adhering tin hydroxide. It was compared with an activated zinc sulfide phosphor. 6g of silver hydrated zinc sulfide phosphor with tin hydroxide attached, 0.3g of PVA
220m of photosensitive resin solution added with ammonium dichromate
It was suspended in l to prepare a phosphor slurry solution. This phosphor slurry solution was applied to the glass panel surface and, as shown in FIG. 2, the glass panel surface was exposed through the shadow mask 1 and then developed to form stripes having a width of about 300 μm. As shown in FIG. 3, the maximum width of the stripe (A) is used to judge whether the shape of the end of the stripe is good or bad.
And the minimum width (B) were measured, and the difference (AB) was taken as the stripe value. The stripe coated with the phosphor obtained in Example 1 had a uniform thickness and was dense. In addition, in the measurement of the stripe shape of the silver-activated zinc sulfide phosphor (conventional phosphor) similar to that of Example 1 except that tin silicate is not attached and only zinc silicate is attached, A = 330.
μm, B = 300 μm, and the stripe value is 30 μm, while the phosphor obtained in Example 1 of the present invention is A
= 320μm, B = 300μm, stripe value is 20μm
And, compared to the conventional phosphor, it is improved by 50%. That is, in the phosphor obtained in Example 1, the outline shape of the stripe could be remarkably improved by depositing tin hydroxide in addition to zinc silicate.

Example 2 100 g of copper and aluminum co-activated zinc sulfide phosphor was added to pure water
After suspending in 250 ml, Sn (SO ₄ ) was added to this phosphor suspension.
10 ml of ₂ aqueous solution (Sn ₂ % content liquid) was added and stirred for 5 minutes. While stirring, add 2% NH ₄ OH aqueous solution dropwise to pH.
After adjusting to 6.5, stirring was stopped and the phosphor particles were allowed to settle. Then, it was filtered, dried, and passed through a 300-mesh sieve to obtain a phosphor in which a tin compound, that is, tin hydroxide, was attached to the surface of the phosphor particles. Next, 100 g of copper- and aluminum-activated zinc sulfide phosphor with tin hydroxide attached to the surface was suspended in 250 ml of pure water, and K ₂ SiO ₃ (SiO ₂ was added to the phosphor suspension. 1.5% of a solution containing 2%) was added with stirring, and ZnSO ₄ (Zn
(Solution containing 2%) was added and stirred. While stirring, 5% NaOH aqueous solution is added dropwise to adjust pH to 7.0. After 30 minutes, 10 ml of Sn (SO ₄ ) ₂ (solution containing 2% Sn) was added and mixed, and 2% NaOH solution was added dropwise to adjust the pH.
Adjusting to 6.5, the phosphor particles were allowed to settle. Then, it was separated by filtration, dried (at 90 ° C. for 10 hours), and passed through a 300-mesh sieve to obtain a phosphor in which tin hydroxide and zinc silicate were attached to the surface of the phosphor particles. Next, using the obtained tin hydroxide-adhered phosphor, Example 1
The value of the stripe shape similar to that was measured. The obtained stripe had a uniform thickness and was dense. In addition, in the measurement of the stripe shape of the same phosphor (conventional phosphor) as in Example 2 except that zinc silicate is adhered instead of tin hydroxide, A = 340 μm and B = 300 μm, and the stripe value is While 40 μm, the phosphor obtained in Example 2 of the present invention has A = 320 μm and B = 300 μm.
m, and the stripe value was 20 μm, which is a half of the conventional value.

Example 3 After suspending 100 g of silver activated zinc sulfide phosphor in 250 ml of pure water, first, 2.0 g of cobalt aluminate was added to this phosphor suspension.
Acrylic emulsion (2% acrylic content)
1 ml was added, the pH was adjusted to 5 with acetic acid, sedimented and decanted until neutral. Next, 50 ml of Sn (SO ₄ ) ₂ aqueous solution (Sn ₂ % content solution) was added and stirred for 5 minutes. 2% NH ₄ OH with stirring
After dropping the aqueous solution and adjusting the pH to 6.0, stop stirring,
The phosphor particles were allowed to settle. Then, filter and dry (at 90 ℃
10 hours) and then pass through a 300 mesh screen,
A phosphor having a tin compound, that is, tin hydroxide, attached to the surface of the phosphor particles was obtained. Next, 100 g of silver-activated zinc sulfide phosphor having tin hydroxide adhered on its surface was suspended in 250 ml of pure water, and 2 g of cobalt aluminate and acrylic emulsion (acrylic 2%) were added to this suspension. 1 ml), pH is adjusted to 5 with acetic acid, the phosphor is allowed to settle and decanted until neutral. Further, 1 ml of K ₂ SiO ₃ (solution containing 2% of SiO ₂ ) is added while stirring, and 0.5 ml of ZnSO ₄ (solution containing 2% of Zn) is further added and stirred. NH ₄ while stirring
A 2% OH aqueous solution is added dropwise to adjust the pH to 6.8. Furthermore,
50 ml of Sn (SO ₄ ) ₂ (solution containing 2% Sn) was added and mixed, a 5% NH ₄ OH aqueous solution was added dropwise, the pH was adjusted to 6.0, and the phosphor particles were allowed to settle. Then, it was filtered and dried (at 90 ° C. for 6 hours) and passed through a 300-mesh sieve to obtain a pigmented phosphor having tin hydroxide and zinc silicate attached to the surface of the phosphor particles. Next, using the obtained phosphor, the stripe shape value was measured in the same manner as in Example 1. The obtained stripe had a uniform thickness and was dense. Further, in the stripe shape measurement using the same phosphor (conventional phosphor) as in Example 3 except that tin silicate is not adhered but only zinc silicate is adhered, A = 320 μm, B = 300 μm
m and the stripe value is 20 μm, whereas in the measurement of the stripe shape using the phosphor obtained in Example 3 of the present invention, A = 310 μm and B = 300 μm, and the stripe value is 10 μm. It was reduced to half.

Example 4 Eurobium activated yttrium oxysulfide phosphor (Y ₂ O ₂ / E
u) After suspending 100 g in 250 ml of pure water, in this suspension,
As in Example 1, 15 ml of SnCl ₄ aqueous solution (Sn 2% content solution)
Was added and stirred for 5 minutes. While stirring, add 5 m of sodium alginate solution (5% content solution) to this phosphor suspension.
The pH was adjusted to 5 with acetic acid, 2% NH ₄ OH Wednesday was added dropwise to adjust the pH to 7.0, stirring was stopped, and the phosphor particles were allowed to settle. Then, it was filtered, dried (90 ° C. for 3 hours), and passed through a 300-mesh sieve to obtain a phosphor having tin alginate attached to the surface of the phosphor particles. Next, this phosphor was treated in the same manner as in Example 1 to obtain a phosphor having tin alginate and zinc silicate attached to the surface of the phosphor particles. In the above examples, zinc silicate is used as the silicate, but instead of zinc silicate, aluminum silicate, or
It is also possible to use magnesium silicate. It is also possible to use zinc phosphate, aluminum phosphate, magnesium phosphate instead of silicate. The phosphor of the present invention adjusts the amount of tin contained in the tin compound in the range of 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the phosphor. If the amount of the tin compound attached is too large or too small, the dispersibility of the phosphor will decrease. The dispersibility of tin compounds with respect to the amount of tin deposited is shown in FIG. However, Fig. 1 shows the sedimentation volume when the amount of zinc silicate adhering to the tin compound on the surface of the phosphor was kept constant at 0.5% by weight and the coating amount of tin contained in tin hydroxide was changed. There is. As for the sedimentation volume, the phosphor of the present invention was used as a PVA-ADC slurry, a certain amount was taken in a sedimentation tube, and it was forcibly sedimented for a certain time by a centrifuge, and the volume was measured. The smaller the sedimentation volume is, the better the dispersibility is, and the phosphor having good dispersibility is properly attached to the panel surface even if the stripe width, which is a measure of the adhesive force, becomes small. Phosphors with a zinc silicate content of 0.5% by weight have the best dispersibility when the amount of tin contained in the tin hydroxide is 0.01 to 0.05% by weight. The volume increases and the adhesive strength decreases. Therefore, the amount of the tin compound deposited is adjusted within the above range in consideration of the dispersibility required for the phosphor. In the above-mentioned examples, the description has been made by using the tetravalent tin salt as the additive of the tin compound attached to the surface of the phosphor particles. You may use the tin salt of. The reason for this is that the divalent tin salt is chemically unstable and substantially changes to the tetravalent tin salt. Further, in the above-mentioned embodiments, the zinc sulfide phosphor is used as the phosphor particles for explanation, but the present invention is not limited to this, and rare earth red light-emitting phosphors such as yttrium oxysulfide phosphor can be used. In addition, the present invention can also be applied to a pigmented red light emitting phosphor and a pigmented blue light emitting phosphor to which pigments such as silicon dioxide, cobalt aluminate and iron oxide are attached.

【The invention's effect】

The phosphor of the present invention has excellent dispersibility for a slurry in forming a fluorescent film of a color television. Therefore, by using the phosphor of the present invention to form a phosphor film for a color television, a uniform and dense phosphor film can be formed. In addition, the phosphor of the present invention can improve the dispersion characteristics in an extremely workable state, and can realize a feature that a phosphor for television having a fine dot stripe can be easily mass-produced. It is shown in FIG. 4 that the phosphor of the present invention exhibits excellent characteristics for forming fine stripes. This figure shows the relationship between the exposure amount and the stripe width. A phosphor having a poor dispersibility has a wide stripe width, and the adhesive strength is reduced at the peripheral edge to increase the stripe value. On the other hand, a phosphor having good dispersibility has a narrow stripe width and is firmly adhered to the whole. In this figure, curve A shows the characteristics of the phosphor of the present invention obtained in Example 1, and curve B shows the characteristics of the conventional phosphor which is the same as that of Example 1 except that the tin compound is not attached. Indicates. As shown by the curve A, the phosphor of the present invention has a narrower stripe width than that of the conventional phosphor, and thus shows that fine stripes can be clearly attached. It will be described with reference to FIG. 2 that a phosphor having a narrow stripe width realizes excellent coating characteristics. FIG. 2 shows the positional relationship of “light source 2-shadow mask 1-coating surface 3” and the distribution of the exposure amount when the fluorescent screen is formed. When the light from the exposure light source 2 is projected on the coating film of the photosensitive binder through the electron beam passage hole of the shadow mask 1, the light transmitted through the hole of the shadow mask 1 is at the center of the phosphor. The light is irradiated without being blocked by the shadow mask 1. However, as the distance from the hole of the shadow mask 1 increases, the light from the light source 2 is blocked by the shadow mask 1, and the distribution of the exposure amount has a trapezoidal shape. The central part (a) is called a true shadow part, and the peripheral part (ab) is called a penumbra part, and the degree of curing gradually decreases from the true shadow part to the penumbra part. Therefore, how to make the true shadow area effective is an important factor for determining the goodness of the adhesive force and the stripe shape. In the phosphor having good dispersibility, the phosphor particles are arranged neatly and uniformly distributed, and the phosphor in the shadow area is firmly and firmly attached to form a narrow stripe clearly. On the other hand, phosphors with poor dispersibility do not have phosphor particles lined up neatly, and the phosphors are attached in a non-uniform state near the boundary between the shadow area and the penumbra area, resulting in a wide stripe width and a stripe value. Grows larger. The phosphor of the present invention has excellent coating characteristics as shown by the curve A in FIG. 4, and can realize the feature that a stripe having a small dot pitch can be clearly formed.

[Brief description of drawings]

FIG. 1 is a graph showing the sedimentation volume of the phosphor of the present invention with respect to the amount of deposited tin, FIG. 2 is a cross-sectional view showing a stripe formation state, and FIG. 3 is an enlarged plan view showing the stripe state.
FIG. 4 is a graph showing the stripe width with respect to the exposure amount. 1 ... Shadow mask, 2 ... Light source, 3 ... Application surface.

 ─────────────────────────────────────────────────── --- Continuation of front page (56) References JP-A-56-18677 (JP, A) JP-A-49-16689 (JP, A) JP-B-46-1627 (JP, B1) JP-B-49- 43075 (JP, B1)

Claims (5)

(57) [Claims] 1. A divalent or tetravalent tin compound is attached to the surface of the phosphor particles in addition to the silicate, and the amount of tin contained in the tin compound is 100 parts by weight of the phosphor. 0.001 ~
A phosphor for a color television, wherein the amount of silicate deposited is adjusted to 0.5 parts by weight and the amount of silicate deposited is adjusted to 2 parts by weight or less. 2. Zinc silicate is used as a silicate, the amount of zinc silicate deposited is about 0.5% by weight, and the amount of tin deposited is 0.01 to 0.0.
The phosphor for a color television according to claim 1, characterized in that the amount is 5% by weight. 3. The phosphor for a color television according to claim 1, wherein the tin compound is organic tin. 4. The phosphor for a color television according to claim 1, wherein the tin compound is tin hydroxide. 5. The phosphor for a color television according to claim 1, wherein the tin compound is stannic acid.