KR100573617B1 - Metal oxide mixed phosphor pastes for plasma display panel and its preparation - Google Patents

Abstract

The present invention relates to a phosphor paste for a plasma display panel and a method of manufacturing the same, wherein the phosphor paste for a plasma display panel of the present invention is prepared of a green phosphor paste of Zn ₂ SiO ₄ : Mn coated on a back panel of a PDP. By adding 1 to 5% by weight of a bipolar metal oxide at the time of operation, the discharge characteristics can be uniformly stabilized by adjusting the negative surface charge of the phosphor to bipolarity when the panel is actually driven.

PDP, green phosphor, surface charge, discharge characteristics, bipolar metal oxide, paste

Description

Phosphor paste for plasma display panel to which metal oxide is added and its manufacturing method {METAL OXIDE MIXED PHOSPHOR PASTES FOR PLASMA DISPLAY PANEL AND ITS PREPARATION}

1 shows a flowchart of the manufacturing method of the present invention,

FIG. 2A is a cross-sectional view of a glass substrate coated with a plasma display panel paste prepared without adding magnesium oxide, using a scanning electron microscope;

Figure 2b is a cross-sectional view of a glass substrate coated with a plasma display panel paste prepared by adding magnesium oxide in accordance with the manufacturing method of the present invention by a scanning electron microscope,

3 is a view showing a change in surface charge according to the amount of magnesium oxide added to a fluorescent film coated with a PDP paste prepared by adding magnesium oxide according to the production method of the present invention.

4 is a surface charge of a fluorescent film coated with a PDP paste prepared by adding a metal oxide in accordance with the production method of the present invention according to the type of metal oxide.

(a) when no metal oxide is added,

(b) zinc oxide is added, and

(c) magnesium oxide is added.

The present invention relates to a phosphor paste for a plasma display panel and a method of manufacturing the same. More specifically, the phosphor paste for the plasma display panel is prepared by adding 1 to 5% by weight of bipolar metal oxide when preparing a green phosphor paste of Zn ₂ SiO ₄ : Mn.

In general, a phenomenon of absorbing external energy to emit visible light is called a luminescene, and a substance causing such a phenomenon is called a phosphor. In addition, phosphors are an essential element for driving various displays, and at the same time, the efficiency of phosphors is a key variable in which the efficiency of display products is directly related.

Examples of a display using such a phosphor include a color brown tube (CRT), a liquid crystal display (LCD), a plasma display panel (hereinafter referred to as "PDP"), and a fluorescent display tube (VFD).

In particular, a PDP that displays an image by using a gas discharge phenomenon between glass substrates is a kind of light emitting device that displays an image by using an internal gas discharge phenomenon. This simple, fast response speed and easy to enlarge screen are used for large screen televisions, monitors, display devices for indoor and outdoor advertising.

In order to manufacture a series of light emitting display elements suitable for the above use, it is essential to manufacture phosphor pastes having better properties. Thus, Korean Patent No. 1999-25859 discloses a conventional composition in which the composition of the phosphor paste consists only of phosphor powder, a binder, a filler, a plasticizer, and a solvent in order to increase the interfacial adhesion of the phosphor film printed on the light emitting display device, especially the back plate of the PDP. In addition, it is known to further add glass frit, surfactants, and antioxidants. Specifically, the glass frit includes about 3% to about 15% of the phosphor powder, and at least two or more of PbO, B ₂ O ₃ , ZnO, SiO ₂ , SnO _2, and Al ₂ O ₃ are mixed. .

In addition, Korean Patent No. 1999-17802 discloses 0.1 to 0.5% by weight of a thermosetting resin in a phosphor paste including a phosphor powder and a binder, thereby enhancing the physical bonding force between particles in the paste during the formation of the phosphor, thereby increasing film adhesion. It is disclosed that the screen brightness can be improved by increasing the discharge space by improving the efficiency and reducing the film thickness.

In addition, Korean Patent No. 1998-1436 is a phosphor paste composition of PDP, and by mixing two or more phosphor powders having different particle diameters, the surface of the fluorescent layer forming a discharge space between the lower substrate and the upper substrate is bent to be formed. Increasing the surface area has been announced to improve the luminous efficiency and thereby the performance of the PDP.

Research to secure the optimal composition of such phosphors is steadily in progress. On the other hand, PDP is a gas discharge phenomenon after red, green, and blue phosphors are applied on the partition walls of the panel, the surface charge changes during discharge, resulting in uneven light emission and low luminous efficiency. .

In US Patent No. 005289081, the surface charge of the phosphor during discharge is (Y, Gd) BO ₃ : Eu + 0.03μc / g, Zn ₂ SiO ₄ : Mn -0.16μc / g, YBO ₃ : Tb + 0.10μc / g And BaMgAl ₁₀ O ₁₇ : Eu +0.15 μc / g, it is revealed that the surface charge phenomenon of the negative electrode is prominent in the case of the green phosphor, Zn ₂ SiO ₄ : Mn. At this time, Zn ₂ SiO ₄ : Mn, which is a green phosphor, is coated on the barrier ribs of the panel and then discharged, and the surface of the entire phosphor (Zn ₂ SiO ₄ : Mn) is caused by the large negative charge of Si-O in the compound of the phosphor. This is a high negative charge. The surface charge of the negative electrode lowers the wall charge holding the partition wall, increases the firing voltage of the manufactured PDP, causes problems such as non-uniform emission and decreases the luminance of light, and thus, the overall PDP. This provides a cause for the discharge efficiency of to be impaired.

However, Zn ₂ SiO ₄ : Mn is also the phosphor most representatively used as a green phosphor for PDP because of its excellent luminous efficiency and color purity under high vacuum and high ultraviolet energy of 140 to 170 nm.

Therefore, while maintaining the advantages of the current green phosphor Zn ₂ SiO ₄ : Mn, a technique for transferring the surface charge of the negative electrode to the surface charge of the positive electrode is being studied, the method to replace the other green phosphor of the positive polarity or bipolar The other phosphors and the green phosphor of the negative electrode were mixed and used to adjust the polarity to neutral. At this time, the green phosphor substitutes YBO ₃ : Tb and (Ba, Sr, Mg) Al ₂ O ₄ : Mn, and the green phosphors are not only significantly different in color purity from the Zn ₂ SiO ₄ : Mn phosphor. , Brightness and thermal stability are inferior. In addition, when the substitute material of the green phosphor is mixed with the phosphor Zn ₂ SiO ₄ : Mn, the surface charge of the negative electrode may be improved, but as the addition ratio of the substitute phosphor increases, the intrinsic characteristics of the Zn ₂ SiO ₄ : Mn may be improved. Is degraded.

In an effort to overcome such a problem, the present inventors, in the previously filed Korean Patent No. 2003-10257, with respect to the green phosphor on the surface of the green phosphor Zn ₂ SiO ₄ : Mn, 1 to 50% by weight of a highly polar metal oxide By coating with an attempt to adjust the surface charge of the phosphor. However, the present invention is to coat the metal oxide on the formed green phosphor surface, a pH control system or a heat treatment step is required.

Therefore, in the present invention, the present invention was completed by confirming that the discharge characteristics of the green phosphor, Zn ₂ SiO ₄ : Mn, can be stabilized by adding the phosphor powder and the bipolar metal oxide when preparing the phosphor paste for PDP.

SUMMARY OF THE INVENTION An object of the present invention is to provide a phosphor paste for PDP in which the negative surface charge of the phosphor is adjusted to the positive polarity when the panel is actually driven, thereby improving discharge characteristics.

Another object of the present invention is to provide a green phosphor for PDP, Zn ₂ SiO ₄ : Mn, to which 1 to 5% by weight of bipolar metal oxide is added in the preparation of the phosphor paste for PDP.

Another object of the present invention is to provide a method for producing a phosphor paste for PDP.

In order to achieve the above object, the present invention provides a phosphor paste for PDP prepared by adding 1 to 5% by weight of a bipolar metal oxide in the production of the phosphor paste. In particular, the phosphor provides a phosphor paste for PDP, wherein the phosphor is a green phosphor of Zn ₂ SiO ₄ : Mn.

In addition, the present invention is the phosphor paste for PDP green phosphor powder having a particle size of 3 nm to 0.5 ㎛ Zn ₂ SiO ₄ : Mn 40 to 60% by weight; 1 to 5% by weight of a bipolar metal oxide having a particle size of 10 nm to 0.1 μm; 7 to 10 wt% binder; And a phosphor paste containing the remaining amount of the organic solvent as a main component, and 2 to 5% by weight of at least two additives selected from fillers, dispersants, plasticizers, and glass frit as additional components, wherein the viscosity of the phosphor paste is 1,000. It is characterized by being 20,000 cps.
In addition, 1) 7 to 10% by weight of the binder is mixed with the organic solvent, or 2 to 5% by weight of two or more additives selected from fillers, dispersants, plasticizers, and glass frits are further mixed, followed by primary stirring. Manufacturing step;
2) adding 1 to 5% by weight of a bipolar metal oxide having a particle size of 10 nm to 0.1 μm into the mixed solution, followed by secondary stirring; And
3) A method of manufacturing a phosphor paste for a plasma display panel comprising mixing green phosphor powder Zn ₂ SiO ₄ : Mn 40 to 60 wt% having a particle size of 3 nm to 0.5 μm in step 1 or after step 2. To provide.

Hereinafter, the present invention will be described in detail.

The present invention provides a phosphor paste for PDP with improved discharge characteristics. More specifically, the present invention provides a phosphor paste for PDP having improved discharge characteristics by adding 1 to 5% by weight of bipolar metal oxide in the manufacture of the phosphor paste.

The composition of the phosphor paste for PDP of the present invention is green phosphor powder Zn ₂ SiO ₄ : Mn 40 to 60% by weight having a particle size of 3 nm to 0.5 μm; 1 to 5% by weight of a bipolar metal oxide having a particle size of 10 nm to 0.1 μm; 7 to 10 wt% binder; And a residual amount of organic solvent as a main component, and 2 to 5% by weight of at least two additives selected from fillers, dispersants, plasticizers, and glass frits as additional components. In addition, surfactants and antioxidants may be further added.

The combination ratio of the composition may vary depending on the phosphor particle diameter, the type of resin of the selected binder, or the type of screen.

In this case, the phosphor that can be used in the present invention is a green phosphor, more preferably Zn ₂ SiO ₄ : Mn. It is preferable that the phosphor has a particle size of 3 nm or more and less than 0.5 μm in powder form.

The binder is used for uniform dispersion between the compositions and is added by 7 to 10% by weight. Preferred binders are used alone or in the form of mixtures thereof selected from the group consisting of cellulose compounds and acrylic resins. In addition, since the binder is an additive that determines the flowability and viscosity of the prepared paste, the binder may affect the addition amount of the phosphor and the addition composition ratio of the bipolar metal oxide according to the type and the addition amount. Most preferably, ethyl cellulose or ethylene glycol diacrylate is used.

In addition, in order to prevent the viscosity of the final phosphor paste from increasing due to the addition of the metal oxide, it is preferable that the addition amount of the binder with respect to the addition amount of the metal oxide is determined by the amount of eliminating the metal oxide.

The solvent may include all organic solvents commonly used in the phosphor paste composition, and in the present invention, butylcarbitol acetate, benzene, toluene, 2-butanone, and tapineol are used.

The present invention is to add 1 to 5% by weight of the bipolar metal oxide, in addition to the composition required for the production of the phosphor paste in order to adjust the negative surface charge of the phosphor to the positive polarity to improve the discharge characteristics, particles of the bipolar metal oxide The size of is 10 nm to 0.1 ㎛, should be particles in the form of fine oxide. At this time, if the content of the bipolar metal oxide is less than 1% by weight, the polarity of the phosphor layer on the panel after the paste printing still shows a negative polarity, and if the above range exceeds 5% by weight, the viscosity of the paste is excessively improved, causing problems in the printing process. This is a cause of reducing the luminous efficiency of the phosphor layer.

Preferred bipolar metal oxides are in the form of a mixture of two or more kinds containing magnesium oxide alone or selected from the group consisting of magnesium oxide (MgO), zinc oxide (ZnO) and aluminum oxide (Al ₂ O ₃ ). More preferably, magnesium oxide and zinc oxide are used alone.

The viscosity of the phosphor paste of the present invention prepared by mixing the composition is preferably 100 to 30,000 cps, and when the viscosity is 1,000 to 20,000 cps, it is most preferable to apply the PDP back plate.

In addition, additives composed of fillers, dispersants, plasticizers, and glass frits typically use those used in phosphor paste compositions.

In addition, in order to perform oxidation during dispersion and heat treatment of each of the above additives, a small amount of a surfactant and an antioxidant may be added as necessary.

The present invention provides a method for producing a phosphor paste for PDP.

More specifically, the method for producing a phosphor paste for PDP includes 1) mixing 7 to 10 wt% of a binder with an organic solvent or 2 to 5 wt% of two or more additives selected from fillers, dispersants, plasticizers, and glass frits. Further mixing to prepare a mixed solution by first stirring;

2) adding 1 to 5% by weight of a bipolar metal oxide having a particle size of 10 nm to 0.1 μm into the mixed solution, followed by secondary stirring; And

3) 40 to 60% by weight of green phosphor powder Zn ₂ SiO ₄ : Mn having a particle size of 3 nm to 0.5 μm is mixed in Step 1 or after Step 2.

PDP phosphor paste prepared by the manufacturing method of the present invention, that is, Zn ₂ SiO ₄ : Mn was applied to a substrate, and the cross-section was examined, and when the anodic metal oxide of the present invention was added, a positive metal oxide was formed on the surface of the phosphor. Observed together ( FIG. 2B ). In addition, the zeta potential generated by coating the substrate using the prepared Zn ₂ SiO ₄ : Mn phosphor paste for PDP was measured, and as the addition amount of the bipolar metal oxide was increased, Zn ₂ SiO ₄ : Mn It can be seen that the surface charge is significantly increased from the negative surface charge to the positive property ( FIG. 3 ).

In particular, when zinc oxide or magnesium oxide alone is added to the bipolar metal oxide, Zn ₂ SiO ₄ : Mn exhibits a transition effect from about 30% up to 50% of the negative surface charge when not added ( Figure 4). ).

Hereinafter, the present invention will be described in more detail with reference to Examples.

This embodiment is intended to describe in detail using the most preferred embodiment of the present invention to the extent that those skilled in the art can easily carry out the technical idea of the present invention, The range is not limited to these examples.

<Example 1> Preparation of phosphor paste for PDP to which magnesium oxide is added 1

To 52 g (52 wt%) of the organic solvent butyl carbitol acetate, 7 g (7 wt%) of ethyl cellulose was added, followed by stirring for 24 hours. After stirring, 1 g (1 wt%) of magnesium oxide was added to the homogeneously mixed solution, followed by further stirring for 24 hours. Thereafter, a green phosphor, Zn ₂ SiO ₄ : Mn 40g (40 wt%) was added to the homogeneously mixed solution, followed by stirring for 48 hours to prepare a phosphor paste for magnesium PDP.

Example 2 Preparation of PDP Paste with Aluminum Oxide Added 2

Except for adding an additive consisting of a dispersant (Alcosperse 602-N, 0.5g) and glass frit (PbO-B ₂ O _3, 3g) in the above embodiment, it was carried out in the same manner as in Example 1.

FIG. 2A is a cross-sectional view of a glass substrate coated with a phosphor paste prepared without adding magnesium oxide, and FIG. 2B is a cross-sectional view of a PDP phosphor paste prepared by adding magnesium oxide to a glass substrate. The results were observed with a scanning electron microscope. As a result, in the case of the paste prepared by adding magnesium oxide of the present invention, Zn ₂ SiO ₄ : Mn phosphor and magnesium oxide, which is a bipolar metal oxide, are observed together, and the size of magnesium oxide is several hundred nm or less, more preferably 50 It was confirmed that it was distributed among the phosphor particles at the nm or less.

<Example 3> Preparation of the phosphor paste for PDP with magnesium oxide 3

The amount of magnesium oxide added was changed to 2g (2% by weight), 3g (3% by weight), 4g (4% by weight), 5g (5% by weight), and thus the amount of added ethyl cellulose was 5g (5% by weight), Except for adjusting to 4g (4% by weight), 3g (3% by weight), 2g (2% by weight), 1g (1% by weight), it was carried out in the same manner as in Example 1.

After applying the prepared phosphor paste to the fluorescent film, it was measured by using a zeta potential (Zeta-Potential analyzer) to observe the effect of the surface charge. The results are shown in Table 1 and FIG. 3.

MgO addition ratio (% by weight) No addition One 2 3 4 5 Addition ratio of ethyl cellulose (wt%) No addition 5 4 3 2 One Surface potential (mV) -32.0 -27.5 -17.0 -8.0 -0.10 -0.05

As shown in Table 1, in the case of green phosphor, Zn ₂ SiO ₄ : Mn prepared without adding magnesium oxide, the surface charge phenomenon of the negative electrode is remarkable, whereas magnesium oxide, which is the bipolar metal oxide of the present invention, is added. In the case of the phosphor paste, it was confirmed that the zeta potential value was significantly reduced. In addition, it was confirmed that as the addition ratio of magnesium oxide increased, the surface charge value of the negative electrode of the green phosphor and Zn ₂ SiO ₄ : Mn transitioned to neutral or bipolar.

 In addition, as a result of observing the luminance according to the amount of magnesium oxide added to the phosphor film coated with the phosphor paste for magnesium oxide, the surface charges of the phosphor continued to increase bipolar as the addition rate of the magnesium oxide salt was increased. In the case of 5% by weight, it was confirmed that many magnesium oxide particles were intercalated between the phosphors to degrade the characteristics of the luminance.

Example 4 Preparation of PDP Paste with Zinc Oxide Added 4

Except for using 1 g (1% by weight) of zinc oxide as the bipolar metal oxide, it was carried out in the same manner as in Example 2.

4 is a potential value of a fluorescent film coated with a phosphor paste for PDP prepared by adding a metal oxide according to the methods prepared in Examples 2 and 4 above. About 50% of the phosphor paste for magnesium PDP prepared in Example 2 with respect to the potential value of the negative electrode of Zn ₂ SiO ₄ : Mn, which was prepared without adding a metal oxide, was prepared in Example 4 Phosphor paste for PDP to which zinc oxide was added was about 30%, showing an effect of transition to bipolarity.

Example 5 Preparation of PDP Paste with Aluminum Oxide Added 5

Except for using 1 g (1% by weight) of aluminum oxide as the bipolar metal oxide, it was carried out in the same manner as in Example 2.

Example 6 Preparation of PDP Paste with Magnesium Oxide and Zinc Oxide Added 6

As the bipolar metal oxide, it was carried out in the same manner as in Example 2, except that 0.5 g (0.5% by weight) of magnesium oxide and 0.5 g (0.5% by weight) of zinc oxide were used.

As described above, the present invention adds 1 to 5% by weight of anodic metal oxide in the manufacture of the phosphor paste, and during the actual driving of the panel, the surface charge of the negative electrode is converted into the bipolar for stabilizing the discharge characteristics. Phosphor paste, Zn ₂ SiO ₄ : Mn.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (6)

Green phosphor powder having a particle size of 3 nm to 0.5 μm Zn ₂ SiO ₄ : Mn 40 to 60 wt%; 1 to 5% by weight of a bipolar metal oxide having a particle size of 10 nm to 0.1 μm; 7 to 10 wt% binder; And Contains the residual amount of organic solvent as a main component, A phosphor paste containing 2 to 5% by weight of at least two additives selected from fillers, dispersants, plasticizers, and glass frits as additional components, wherein the metal paste is characterized in that the viscosity of the phosphor paste is 1,000 to 20,000 cps. Paste for used plasma display panels. delete The bipolar metal oxide of claim 1, wherein the bipolar metal oxide is magnesium oxide (MgO), zinc oxide (ZnO), aluminum oxide (Al ₂ O ₃ ), tin oxide (SnO ₂ ), and yttrium oxide (Y ₂ O ₃ ). A phosphor paste for plasma display panel to which the metal oxide is added, characterized in that at least two or more mixtures comprising magnesium oxide selected from the group consisting of: 1) 7 to 10% by weight of the binder is mixed with the organic solvent or 2 to 5% by weight of at least two additives selected from fillers, dispersants, plasticizers, and glass frits are first mixed to prepare a mixed solution. step; 2) adding 1 to 5% by weight of a bipolar metal oxide having a particle size of 10 nm to 0.1 μm into the mixed solution, followed by secondary stirring; And 3) The plasma display of claim 1, wherein the green phosphor powder Zn ₂ SiO ₄ : Mn 40 to 60% by weight having a particle size of 3 nm to 0.5 μm is mixed in step 1 or after step 2. Method for producing phosphor paste for panel. 5. The method of claim 4, wherein the organic solvent is a mixture of two papers selected from the group consisting of butyl carbitol acetate, benzene, toluene, 2-butanone, and tapineol. Way. The method of manufacturing a phosphor paste for plasma display panel according to claim 4, wherein the binder is made of one or a mixture thereof selected from the group consisting of a cellulose compound and an acrylic resin.

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