KR19990017460A - Phosphor Paste of Plasma Display Panel and Manufacturing Method Thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paste used for applying a phosphor of a plasma display panel and a method for producing the paste, and in particular to spray drying on a partition wall by selecting an appropriate composition of the material constituting the paste and having a small particle size of an inorganic binder among the materials. Thus, the phosphors of green, red, and blue are adhered to the substrate and the phosphor density is improved by obtaining a plasma display panel with an accurate thickness and precise shape of the phosphor and easily adjusting the color intensity. And an inorganic binder which serves to lower the firing temperature of the phosphor, an organic binder for uniformly distributing the inorganic binder and the phosphor and improving the coating property of the phosphor, and a method of manufacturing the paste. .

Description

Phosphor Paste of Plasma Display Panel and Manufacturing Method Thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paste used for applying a phosphor of a plasma display panel and a method for producing the paste, and in particular to spray drying on a partition wall by selecting an appropriate composition of the material constituting the paste and having a small particle size of an inorganic binder among the materials. Thereby, the present invention relates to a paste of a plasma display panel and a method of manufacturing the same, in which a precise thickness and precise form of a phosphor can be obtained and a plasma display panel with easy color intensity control can be obtained.

In general, plasma display panels, which have recently attracted great attention as large display devices, are classified into AC type and DC type.

AC Plasma Display Panel (PDP) has a structure in which each electrode is covered with a dielectric layer and an MgO layer, and any type of phosphor excites a phosphor coated with ultraviolet rays generated by the discharge between the electrodes on the inner surface of the discharge cell. This is a structure in which visible light is emitted by the photoluminescence principle.

On the other hand, in the case of DC type PDP, the cathode and the anode are exposed to the discharge space. The structure of the lower plate of the general AC type PDP includes a substrate 1, a data electrode 2 vertically extended on the substrate, and a dielectric layer 3 enclosed to protect the data electrode. And a barrier rib 5 for longitudinally separating the data electrodes, and red, green, and blue phosphors 10, 20, and (applied to the barrier rib and the dielectric layer to emit visible light). 30).

Such a PDP can increase the light emission time by using a memory effect, and can be easily applied to a large sized and thinned panel because a high luminance is obtained regardless of the panel size.

However, the conventional PDP is problematic in terms of low contrast ratio, high discharge start voltage, color purity of phosphor, low luminance and lifetime.

In order to eliminate the above problems, proper application of the phosphor has a decisive effect on the color purity and luminance of the phosphor.

In PDPs, it is advantageous to have the brightness as high as possible, so an optimum phosphor thickness is required. If less than or greater than the optimal phosphor thickness, the brightness is reduced.

The partition walls are manufactured using various advantages and disadvantages by various methods such as a printing method, an optical etching method, and a sand blast method, but the coating of the phosphor is performed only by the printing method.

Since the phosphor is a solid powder, a paste is prepared by mixing with an organic material and printing.

However, the method of increasing the brightness by applying the phosphor on the partition wall requires a high printing technique, and the flowability of the phosphor must be properly adjusted, which is a very difficult technique.

When printing a conventional phosphor, about 60% by weight of an organic binder is added, and the remainder is composed of a phosphor and an inorganic binder.

As the content of the organic binder increases, the viscosity decreases. However, when the paste is prepared by selecting a particle having a particle diameter of about 1 to 2 μm, the flowability of the viscosity decrease can be controlled.

However, the smaller the particle size of the inorganic binder is, the higher the sintered density becomes, the post-firing paste shrinks, the shape becomes unstable when the phosphor is applied, and a high density inorganic binder occupies the surface of the phosphor, thereby degrading luminescence properties. have.

In addition, even if the flow characteristics are good when leveling, which causes the paste to flow down the barrier ribs, the thickness of the barrier ribs is thin so that the luminance characteristics are deteriorated. There is a problem that remains.

Accordingly, the present invention was devised to solve the above-described problems, and by selecting the appropriate composition of the material forming the paste and the small particle size of the inorganic binder in the material and spray-drying it on the partition wall, the precise thickness of the phosphor And it is an object of the present invention to provide a plasma display panel paste and a method of manufacturing the same to obtain a precise display, and to obtain a plasma display panel with easy color intensity control.

1 is a view showing the lower plate of the AC plasma display panel

2 is a view showing the structure of the partition wall and phosphors of red, green, and blue

3A is a view showing a red phosphor and a mask used when applying the phosphor;

3B shows a green phosphor and a mask used when applying the phosphor.

3 (c) shows a blue phosphor and a mask used when applying the phosphor.

Explanation of symbols for the main parts of the drawings

1 substrate 10 red phosphor

2: data electrode 20: green phosphor

3: dielectric layer 30: blue phosphor

4: fluorescent layer 50: mask

5: bulkhead

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

The phosphor paste of the plasma display panel according to the present invention includes a phosphor powder of green, red or blue, an inorganic binder which bonds the phosphor to a substrate, improves the integration density of the phosphor, and lowers the firing temperature of the phosphor; In the phosphor paste comprising an organic binder comprising a low boiling point solvent and a high boiling point solvent in order to uniformly distribute the inorganic binder and the phosphor and improve the coating properties of the phosphor, the total of the phosphor and the inorganic binder combined 20 The organic binder is set to 0.5 to 10% by weight with respect to the high boiling point solvent, and the inorganic binder is set to 1 to 20% by weight with respect to the phosphor in powder form. , The low boiling point solvent is added so that the paste viscosity is 100 ~ 10,000 cps It characterized by comprising, including.

The phosphor paste manufacturing method of the plasma display panel according to the present invention comprises the steps of: uniformly mixing a red, green or blue phosphor, an organic binder and an inorganic binder with a low boiling point solvent and a high boiling point solvent (S1); Spray drying using a mask 50 for covering the green phosphor 20, the blue phosphor 30, and the partition wall 5 to apply the red phosphor 10 (S2); Spray drying using a mask 50 for covering the red phosphor 10, the blue phosphor 30, and the partition wall 5 to apply the green phosphor 20 (S3); And spray drying using a mask 50 for covering the red phosphor 10, the green phosphor 20, and the partition wall 5 to apply the blue phosphor 30 (S4).

In the present invention, in order to eliminate the above-mentioned conventional problems, phosphor coating is performed using a spray dryer during phosphor printing.

FIG. 2 is a diagram showing a barrier rib and a phosphor structure of a PDP, and the barrier ribs are alternately composed of one of red, green, and blue phosphors.

In the present invention, in order to solve the above-mentioned conventional problems, a method of applying green, red and blue phosphors sequentially with a spray dryer as in FIG. 3 using red, green, and blue masks is used.

In order to apply the phosphor in the same manner as above, the paste used in the conventional printing method cannot be used because the viscosity is too high.

Therefore, a low viscosity paste suitable for the spray drying process is required.

The phosphor used in the PDP should have excellent light emission characteristics and coating characteristics for panels such as luminance, chromaticity, afterimage, luminous efficiency, gray scale display, and lifetime.

The conditions for the phosphor for improving the light emitting characteristics of the panel should be excellent in the absorption efficiency (Vacuum Ultra Violet: VUV), heat resistance, crystallinity, etc., the characteristics of the phosphor to determine the coating characteristics is the shape and particle size of the incident Distribution, dispersibility, etc.

Green phosphors used in PDP include Zn ₂ SiO ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn, BaMgAl ₁₄ O ₂₃ : Mn, SrAl ₁₂ O ₁₉ : Mn, ZnAl ₁₂ O ₁₉ : Mn, CaAl ₁₂ O ₁₉ : Mn, YBO ₃ : Tb, LuBO ₃ : Tb, GdBO ₃ : Tb, ScBO ₃ : Tb, Sr ₄ Si ₃ O ₈ C _{l 4} : Eu, etc. are used.

Red phosphors include Y ₂ O ₃ : Eu, Y ₂ SiO ₅ : Eu, Y ₃ Al ₅ O ₁₂ : Eu, Zn ₃ (PO ₄ ) ₂ : Mn, YBO ₃ : Eu, (Y, Gd) BO ₃ : Eu, GdBO ₃ : Eu, ScBO ₃ : Eu, LuBO ₃ : Eu, etc. are used, and blue phosphors include CaWO ₄ : Pb, Y ₂ SiO ₅ : Ce, BaMgAl ₁₄ O ₂₃ : Eu, and the like.

Since the green phosphor has a radiation extinction time of 25 to 35 ms up to 10% intensity, a phenomenon that an afterimage remains after the reaction is very slow in the representation of a moving image is a problem, and Zn ₂ SiO ₄ : Mn is used as a material of the green phosphor. Improvements were made.

When doping Mn, as the concentration increases, the afterimage phenomenon is reduced. However, if the panel is set to 0.8 to 2.6% by weight, the radiation extinction time can be shortened.

In addition, phosphors such as Mg (Ga, Al) ₂ O ₄ : Mn, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce using Mn, Ce, Tb, etc. as dopants have a great effect on improving life and improve color purity. BaAl ₁₂ O ₁₉ : Mn and YBO ₃ : Tb may be used for the purpose.

Among the phosphors doped with EU ³⁺ and Mn, the red phosphor has excellent excitation characteristics of YBO ₃ : EU in the VUV region of 147 nm, and efficiency can be optimized by replacing Y with Gd.

In the blue phosphor, since Y ₂ SiO ₅ : Ce is insufficient in efficiency and color purity, it is attempted to use new doping materials such as Ce, Ti, Eu ³⁺ as a blue light emitting center, but recently BaMgAl ₁₄ O ₂₃ : EU It is used.

In addition, BaMgAl ₁₀ O ₁₇ : EU ^{2+ is} also used to improve the lifespan and the phenomenon of color change by changing the emission spectrum during use.

In the green phosphor, a phenomenon in which an afterimage remains and a lifespan of a blue phosphor are a big problem to be solved. In order to improve panel brightness, matching is important during coating.

In order to spray dry such phosphors, a special paste is required.

The paste is largely composed of a phosphor, an inorganic binder, and an organic binder, and the phosphor is separated into red, green, and blue phosphors.

The inorganic binder is for adhering the phosphor to the substrate, and SiO ₂ , B ₂ O ₃ , MgO, Al ₂ O ₃ , PbO, frit glass, or a mixture of two or more thereof may be used.

The organic binder serves to uniformly disperse the phosphor and the inorganic binder, and has a high boiling point solvent compound such as cellulose-based high molecular compound, butyl carbitol acetate α-Terpineol, isoamyl acetate, polyvinyl alcohol, polyvinyl acetate, poly Mixtures of vinyl butyral and glycerol may be used.

In order to increase the low viscosity required for the spray drying process, a solvent having a low boiling point such as ethanol, methanol, isopropanol, acetone, etc. is used in addition to the organic binder.

The composition of the paste as described above sets the ratio of the inorganic binder in which the phosphor is contained in the organic binder to 20 to 60% by weight, more preferably 30 to 50% by weight.

As the organic binder, a cellulose-based polymer material is prepared by preparing 0.5 to 10% by weight, more preferably 1 to 5% by weight, based on the high boiling point solvent as described above.

As the inorganic binder, an inorganic binder is used in an amount of 1 to 20% by weight, more preferably 1 to 10% by weight, most preferably 2 to 5% by weight, based on the phosphor powder.

When the green phosphor is used in the same composition as the red phosphor and the blue phosphor, the light emission becomes stronger, so only a relatively small amount needs to be added.

As for the composition of the green fluorescent substance with respect to the said inorganic binder, 1 to 4 weight% is the best.

If the composition of the phosphor is increased, the luminous efficiency may be relatively excellent, but the adhesion with the substrate is poor, so that packaging is difficult to be made efficiently.

Looking at the method for producing a paste according to the present invention.

The phosphor having the above composition, the organic binder and the inorganic binder are uniformly mixed with a low boiling point solvent. (S1)

In order to apply the red phosphor 10 as shown in FIG. 3A, spray drying is performed using a mask 50 including the green phosphor 20, the blue phosphor 30, and the partition wall 5 (S2).

In order to apply the green phosphor 20 as shown in FIG. 3B, spray drying is performed using a mask 50 including the red phosphor 10, the blue phosphor 30, and the partition wall 5 (S3).

In order to apply the blue phosphor 30 as shown in FIG. 3 (c), it is spray-dried using a mask 50 including the red phosphor 10, the green phosphor 20, and the partition wall. (S4)

The content of the low boiling point solvent used in the step (S1) depends on the content of the organic binder and the inorganic binder used, the particle size distribution of the phosphor powder and the particle size and dispersibility, but most importantly, the paste according to the addition of the low boiling point solvent Precipitation and fogging due to non-uniformity should not occur.

The state of the paste is preferably about 100 to 10,000 cps in viscosity after mixing the solvent, and most preferably about 1000 to 5,000 cps.

The pressure of the nozzle for spray drying in steps S2, S3 and S4 is best when the pressure is 2 to 10 Kg / cm ² .

The spray drying time depends on the desired thickness and concentration of the phosphor, the content of the organic binder and the inorganic binder, but after 5 minutes, a thickness of 10 μm or more can be obtained after the phosphor is fired. do.

After spray-drying each phosphor, the organic binder and the inorganic binder remaining in the mask can be recovered and used again. At this time, since the low boiling point solvent components are all evaporated, the low boiling point solvent can be mixed to adjust the viscosity. have.

As described in detail above, the present invention, by selecting the appropriate composition of the material forming the paste and the particle size of the inorganic binder in the material and spray-drying on the partition wall, it is possible to obtain the precise thickness and precise shape of the phosphor, color There is an effect of obtaining a plasma display panel with easy intensity control.

Claims (6)

Green, red or blue phosphor powder, an inorganic binder which bonds the phosphor to a substrate, improves the density of phosphor phosphor, and lowers the firing temperature of the phosphor; and uniformly distributes the phosphor and the phosphor. In the phosphor paste comprising an organic binder containing a low boiling point solvent and a high boiling point solvent in order to improve the coating characteristics of, the combination of the phosphor and the inorganic binder is set to 20 to 60% by weight of the total, the organic binder The polymer material of the cellulose-based polymer is set at 0.5 to 10% by weight based on the high boiling point solvent, the inorganic binder is set to 1 to 20% by weight based on the phosphor in powder form, and the low boiling point solvent has a paste viscosity of 100 to 10,000 cps. The phosphor paste of the plasma display panel, characterized in that added so as to. The method according to claim 1, wherein the phosphor and the inorganic binder are combined at 30 to 50% by weight of the total, the organic binder is a cellulose-based polymer material is set to 1 to 5% by weight with respect to the high boiling point solvent, The inorganic binder is set to 1 to 10% by weight based on the phosphor in the form of powder, and the low boiling point solvent is added to the paste viscosity of 1,000 to 5,000 cps, the phosphor paste of the plasma display panel. The method of claim 1 or 2, wherein the high boiling point solvent is butyl carbitol acetate, α-Terpineol or asoamyl acetate, and the low boiling point solvent is ethanol, methanol, isopropanol, acetone, etc., characterized in that , Phosphor paste in plasma display panel. Uniformly mixing the red, green, or blue phosphor, the organic binder, and the inorganic binder with a low boiling point solvent and a high boiling point solvent (S1); Spray drying using a mask 50 for covering the green phosphor 20, the blue phosphor 30, and the partition wall 5 to apply the red phosphor 10 (S2); Spray drying using a mask 50 for covering the red phosphor 10, the blue phosphor 30, and the partition wall 5 to apply the green phosphor 20 (S3); And spray drying using a mask 50 for covering the red phosphor 10, the green phosphor 20, and the partition wall 5 to apply the blue phosphor 30, S4. Method for producing phosphor paste in plasma display panel. The method of claim 4, wherein the combination of the phosphor and the inorganic binder is set to 30 to 50% by weight of the total, the organic binder is a cellulose-based polymer material is set to 1 to 5% by weight relative to the high boiling point solvent, The inorganic binder is set to 1 to 10% by weight relative to the phosphor in the form of a powder, and the low boiling point solvent is added to the paste viscosity of 1,000 to 5,000 cps, characterized in that the phosphor paste manufacturing method of the plasma display panel. The plasma display panel according to claim 5, wherein the high boiling point solvent is butyl carbitol acetate, α-Terpineol or asoamyl acetate, and the low boiling point solvent is ethanol, methanol, isopropanol, acetone, or the like. Phosphor paste manufacturing method.