KR100315113B1 - Method for treating surface of phosphors for PDP and surface-treated phosphors for PDP manufactured using the same - Google Patents

Abstract

The present invention comprises the steps of preparing an aqueous dispersion of the ball mill-treated PDP phosphor; Preparing a mixture by adding a surface treatment dispersion comprising at least one selected from the group consisting of silica, titania, water glass, zinc salt and aluminum salt to the phosphor aqueous dispersion; And a phosphor surface treatment method for PDP, and a phosphor for PDP surface treated by the method, comprising adjusting the pH of the mixture to 5 to 8. Since the surface of the phosphor maintains a constant charge, the phosphor does not reaggregate even after the ball mill treatment, and the viscosity of the phosphor paste containing the phosphor is not high. Therefore, the fluorescent film manufactured by using such a phosphor paste can exhibit excellent fluorescent film characteristics without being thick.

Description

Surface treatment method of PDP phosphor and surface treated by PDP {Method for treating surface of phosphors for PDP and surface-treated phosphors for PDP manufactured using the same}

The present invention relates to a PDP phosphor surface treatment method and a PDP phosphor surface-treated by the method, and more particularly, a PDP phosphor for preventing re-agglomeration of the phosphor by maintaining a constant charge on the surface of the PDP phosphor It relates to a surface treatment method of and a surface treated phosphor for PDP produced by this method, the surface charge is kept constant and the dispersibility is improved.

Phosphor refers to a material having a property of emitting light due to energy stimulation other than temperature radiation, and most of the phosphors that are practically used today are artificially synthesized by industrial technology rather than minerals of natural acid.

Phosphors are generally used for light sources such as fluorescent lamps, fluorescent mercury lamps, radiation lamps and the like; For display elements such as cathode ray tubes, electroluminescent elements, plasma display panels (PDPs) and the like; And X-ray sensitizers, scintillaters, etc., and other detection devices.

Such phosphor should be selected to have the characteristics of excitation in the wavelength range of the light source to which the device employing it is exposed, and the current saturation characteristics, deterioration characteristics, luminance, color purity, afterglow characteristics, driving voltage, high current density suitable for each application Resistance and other physical properties under the following conditions should be provided preferably.

Among the above-mentioned phosphors, a method for producing a phosphor for PDP can be roughly classified into a fluxing method and a fluxless method. Of these, the non-melting method is a method of mixing the raw material powders for manufacturing the phosphor and then firing, which has a disadvantage that the firing temperature is too high to increase the production cost.

What is proposed as a way to overcome the drawbacks of the non-melting method is a flux method of dry mixing and calcining by adding a flux to the raw material powder in the production of the phosphor. The advantage of using the flux method is that it can be fired at low temperatures, but the ball mill process should be carried out after firing to prevent particle binding.

However, there is a problem that re-agglomeration of the phosphor occurs due to abrasion of the surface of the phosphor during such a ball mill process, and the viscosity of the paste is increased when the paste is prepared for manufacturing the phosphor film. As the viscosity increases, the adhesive content in the paste needs to be reduced, which causes elasticity degradation and thickens the thickness of the fluorescent film in the partition, thereby degrading the fluorescent film properties.

The present invention is to overcome this problem.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a surface treatment method of a phosphor for PDP for preventing reaggregation of the phosphor for PDP and an increase in viscosity of the phosphor paste.

Another technical problem to be achieved by the present invention is to provide a phosphor for surface-treated PDP so that the surface charge is kept constant.

1 is a photograph showing a fluorescent film formed using a phosphor paste containing a conventional phosphor for PDP.

2 is a photograph showing a fluorescent film formed using a phosphor paste containing a phosphor for PDP surface-treated according to the method of the present invention.

Technical problem of the present invention comprises the steps of: a) preparing an aqueous dispersion of the phosphor for PDP ball milled; b) preparing a mixture by adding a surface treatment dispersion comprising at least one selected from the group consisting of silica, titania, water glass, zinc salt and aluminum salt to the aqueous dispersion of the phosphor; And c) it can be made by the surface treatment method of the phosphor for PDP comprising the step of adjusting the pH of the mixture to 5-8.

Another technical problem of the present invention is at least one selected from the group consisting of a phosphor for PDP, and a surface of the phosphor for PDP and selected from the group consisting of silica, titania, sodium oxide, sodium hydroxide, zinc oxide, zinc hydroxide, aluminum oxide and aluminum hydroxide. It can be made by the surface treatment phosphor for PDP, characterized in that it comprises a colloidal fine particles of.

₁₂ O Eu, BaAl _19:: In the surface treatment of the phosphor process according to the invention, a phosphor for the PDP are typically but not limited to, if special available phosphor, BaMgAl ₁₀ O _l7 used in the field of the present invention, Mn, One selected from the group consisting of Zn ₂ SiO ₄ : Mn YBO ₃ : Tb and (Y, Gd) BO ₃ : Eu can be preferably used.

In addition, the solid content in the surface treatment dispersion is preferably 1% by weight or less based on the total weight of the phosphor, and more preferably adjust the pH of the mixture to 7-8 in the step (c).

On the other hand, in the phosphor for PDP surface-treated according to the method of the present invention, it is preferable that the adhesion amount of the colloidal fine particles is 1% by weight or less with respect to the total weight of the phosphor, and the average particle diameter is 0.5 µm or less.

When the adhesion amount exceeds 1% by weight based on the total weight of the phosphor, colloidal particles surrounding the surface of the phosphor are not preferable because they hinder the absorption of vacuum ultraviolet rays and lower the fluorescence properties.

When the surface of the phosphor for PDP is treated according to the present invention, the charge on the surface of the phosphor is kept constant so that the dispersed phosphor does not reaggregate.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited to these Examples and Comparative Examples.

Example 1

A ball dispersion-treated blue luminescent phosphor (BaMgAl ₁₀ O ₁₇ : Eu) 100g was dispersed in water to prepare an aqueous dispersion of the blue luminescent phosphor. Then, a silica dispersion (silica content: 0.2 g) was added to the phosphor aqueous dispersion and mixed, and then the pH of the mixture was adjusted to 7. The mixture was filtered under reduced pressure, and then the filtrate was dried and calcined to obtain a surface-treated blue light emitting phosphor having colloidal silica fine particles having an average particle diameter of 0.05 μm on the surface.

The luminance of the obtained surface-treated phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

At this time, the phosphor paste is obtained by dispersing 40 g of the obtained phosphor in 60 g of a dispersion medium in which ethyl cellulose and butyl carboxyacetate are mixed in a weight ratio of 11:89.

On the other hand, the fluorescent film as shown in FIG. 1 was obtained using the obtained phosphor paste.

Example 2

A ball mill-treated green luminescent phosphor (BaAl ₁₂ O ₁₉ : Mn) 100g was dispersed in water to prepare an aqueous dispersion of the green luminescent phosphor. Silica dispersion (silica content: 0.1 g) and 4 ml of Na ₂ O.SiO ₂ aqueous solution (2% concentration) were added to this aqueous dispersion, mixed, and the pH of the mixture was adjusted to 7. The mixture was filtered under reduced pressure, and then the filtrate was dried and calcined to obtain a surface treated green light emitting phosphor having colloidal silica, sodium oxide and sodium hydroxide fine particles having an average particle diameter of 0.05 μm on the surface.

As in Example 1, the luminance of the obtained surface-treated phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

Example 3

A ball mill-treated green luminescent phosphor (Zn ₂ SiO ₄ : Mn) was dispersed in water to prepare an aqueous dispersion of the green luminescent phosphor. To this aqueous dispersion, silica dispersion (silica content: 0.1 g), 4 ml of Na ₂ O.SiO ₂ aqueous solution (2% concentration) and ZnSO ₄ aqueous solution (solid content: 0.2 g) were added and mixed, followed by mixing of the mixture. The pH was adjusted to 7. The mixture was filtered under reduced pressure, and the filtrate was dried and calcined to obtain a surface-treated green light emitting phosphor having colloidal silica, sodium oxide, sodium hydroxide, zinc oxide and zinc hydroxide fine particles having an average particle diameter of 0.05 μm on the surface.

As in Example 1, the luminance of the obtained surface-treated phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

Example 4

Colloidal titania, sodium oxide, sodium hydroxide, zinc oxide, and hydroxide having an average particle diameter of 0.05 µm on the surface, except that a titania dispersion (titania content: 0.1 g) was added instead of the silica dispersion. The surface-treated green light-emitting phosphor to which zinc fine particles adhered was obtained.

As in Example 1, the luminance of the obtained surface-treated phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

Example 5

A ball dispersion-treated red light emitting phosphor ((Y, Gd) BO ₃ : Eu) 100g was dispersed in water to prepare an aqueous dispersion of the red light emitting phosphor. Silica dispersion (silica content: 0.05 g), 4 ml of Na ₂ O.SiO ₂ aqueous solution (2% concentration) and Al ₂ (SO ₄ ) ₃ aqueous solution (solid content: 0.05 g) were added to the aqueous dispersion, and mixed. The pH of this mixture was then adjusted to 7. The mixture was filtered under reduced pressure, and then the filtrate was dried and calcined to obtain a surface-treated red light-emitting phosphor having colloidal silica, sodium oxide, sodium hydroxide, aluminum oxide and aluminum hydroxide fine particles having an average particle diameter of 0.05 μm on the surface.

As in Example 1, the luminance of the obtained surface-treated phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

Comparative Example 1

A ball mill-treated blue phosphor (BaMgAl ₁₀ O ₁₇ : Eu) was dispersed in a dispersion medium in which ethyl cellulose and butyl carboxyacetate were mixed at a weight ratio of 11:89 to prepare a phosphor paste.

The luminance of the blue light-emitting phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

In addition, the fluorescent film formed using the fluorescent substance paste thus obtained is shown in FIG.

Comparative Example 2

A ball mill-treated green light emitting phosphor (BaAl ₁₂ O ₁₉ : Mn) was dispersed in a dispersion medium in which ethyl cellulose and butyl carboxyacetate were mixed at a weight ratio of 11:89 to prepare a phosphor paste.

The luminance of the green light-emitting phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

Comparative Example 3

The ball milled green phosphor (Zn ₂ SiO ₄ : Mn) was dispersed in a dispersion medium in which ethyl cellulose and butyl carboxyacetate were mixed at a weight ratio of 11:89 to prepare a phosphor paste.

The luminance of the green light-emitting phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

Comparative Example 4

A ball milled red phosphor ((Y, Gd) BO ₃ : Eu) was dispersed in a dispersion medium in which ethyl cellulose and butyl carboxyacetate were mixed in a weight ratio of 11:89 to prepare a phosphor paste.

The luminance of the red light-emitting phosphor and the viscosity of the phosphor paste prepared using the phosphor were measured and shown in Table 1 below.

Luminance of Phosphor (%) Viscosity of Phosphor Paste (Pas) Example 1 99 29000 Example 2 101 26000 Example 3 99 30000 Example 4 100 28000 Example 5 99 28000 Comparative Example 1 100 38000 Comparative Example 2 100 45000 Comparative Example 3 100 41000 Comparative Example 4 100 40000

From the results of Table 1, the phosphor for the PDP surface-treated according to the present invention can be seen that the viscosity is significantly lowered when the paste is prepared while maintaining the brightness at about the same level as before the surface treatment.

Therefore, the fluorescent film produced therefrom is not thick but uniform.

FIG. 1 shows a fluorescent film formed by using a phosphor paste containing a phosphor for a conventional PDP which is not surface treated, and FIG. 2 shows a fluorescent film formed using a phosphor paste containing a surface treated phosphor prepared according to the present invention. It can be clearly contrasted from.

That is, when comparing a and b showing the fluorescent film portions in FIGS. 1 and 2, respectively, it can be seen that the fluorescent film portion a of FIG. 1 is significantly thicker.

Since the surface treated PDP phosphor according to the present invention maintains a constant charge, the phosphor does not reaggregate even after the ball mill treatment, and the viscosity of the phosphor paste including the same is not high. Therefore, the fluorescent film manufactured by using such a phosphor paste can exhibit excellent fluorescent film characteristics without being thick.

Claims (4)

a) preparing an aqueous dispersion of the ball mill-treated PDP phosphor; b) preparing a mixture by adding a surface treatment dispersion comprising at least one selected from the group consisting of silica, titania, water glass, zinc salt and aluminum salt to the phosphor aqueous dispersion; And c) adjusting the pH of the mixture to 5 to 8; and a surface treatment method of the phosphor for PDP. The surface treatment method of the phosphor for PDP according to claim 1, wherein the solid content in the surface treatment dispersion is 1% by weight or less based on the total weight of the phosphor. The surface treatment method of the phosphor for PDP according to claim 1, wherein the pH is adjusted to 7-8 in step (c). Phosphor for PDP, and It is attached to the surface of the phosphor for PDP, and comprises at least one colloidal fine particles selected from the group consisting of silica, titania, sodium oxide, sodium hydroxide, zinc oxide, zinc hydroxide, aluminum oxide and aluminum hydroxide, A surface-treated phosphor for PDP, wherein the amount of adhesion is 1% by weight or less based on the total weight of the phosphor and its average particle size is 0.5 µm or less.