KR20080007894A - Blue phosphors for plasma display pannel and plasma display pannel empolying the blue phosphors layer - Google Patents

Abstract

A blue phosphor for a plasma display panel(PDP), a method for preparing a PDP by using the phosphor, and a PDP prepared by the method are provided to improve brightness and luminous characteristics in case of the use of a long time and to enhance lifetime performance. A blue phosphor for a PDP is represented by (Ba_(1-x-y)) D_x MgAl10O17:Eu_y, wherein D is Sr or Ca; 0.001<=x<=1.0; and 0.01<=y<=0.5. Preferably the phosphor has a metal oxide coating layer comprising aluminum oxide (Al2O3) on the surface. Preferably the content of D is 2-10 parts by weight based on 100 parts by weight of the total weight; and the phosphor has an average diameter of 0.1-2 micrometers.

Description

Plasma display panel comprising a blue phosphor for plasma display panel and a fluorescent film formed therefrom {Blue phosphors for plasma display pannel and plasma display pannel empolying the blue phosphors layer}

1 is a perspective view schematically showing a plasma display panel manufactured according to an embodiment of the present invention.

2 is a diagram showing a PL emission spectrum of a blue phosphor according to the present invention.

3 is a view showing the amount of change in the color coordinate CIE y value of the blue phosphor.

4 is a diagram showing a decrease in peak intensity of a spectrum of a blue phosphor.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel having a blue phosphor for plasma display panel and a fluorescent film formed therefrom. It relates to a display panel.

Phosphor is a material that emits light by energy stimulation. It is generally used in light sources such as mercury fluorescent lamps and mercury-free fluorescent lamps, and various devices such as electron emitting devices and plasma display panels. It is expected to be used for this purpose.

Plasma Display Panel (PDP) is a display using light emission by ultraviolet rays generated by discharge of a mixed gas of neon and xenon encapsulated between glass substrates. At this time, each phosphor generates visible light by resonance emission light (147 nm vacuum ultraviolet ray) of xenon (Xe) ions.

The phosphor for PDP should have excellent discharge characteristics, luminescence brightness and color coordinates, and short afterglow time. In the PDP, the phosphor layer has a different material composition according to red, green, and blue, and the surface charging characteristic is different according to the kind of material. When the surface charging characteristic is a positive value, the probability of discharge failure is low. However, when the surface charging characteristic is a negative value, the probability of discharge failure is high. This probability is closely related to the driving method, but in order to increase the discharge stability of the PDP and reduce the discharge failure rate, red, green, and blue phosphors are selected so that the surface charging characteristic has a positive value regardless of red, green, and blue. It is desirable to.

As of a blue phosphor for a PDP is BaMgAl ₁₀ O _17: Eu ^{2 +} of the fluorescent material is Ba series is generally used. However, when the panel is made of the Ba-based phosphor, deterioration of the phosphor proceeds, resulting in a drop in color. This phenomenon is the oxidation state of the Ba of the emission center in series fluorescent Eu ^{2 +} is the incomplete oxidation in the panel state proceeds to a result that this color degradation appears because the movement made the transition to Eu ^{3 +} emission wavelength to the long wavelength side There is a problem that the life characteristics are degraded.

Thus, as a way to solve this problem, U.S. Pat.No. 6,187,225 discloses (La _{1 -xy- z} Tm _x Li _y AE _z ) PO ₄ (AE is an alkaline rare earth metal, 0.001 <x <0.05, 0.01 <y <0.05, 0 <z <0.05) is described in combination with the Ba-based phosphor. In addition, Korean Patent Publication No. 2003-14919 discloses a Ba-based phosphor including a spinel layer and a conductive layer, and selectively surface-modified only the conductive layer portion.

However, there is still a lot of research to improve the lifespan characteristics of using blue phosphors.

In order to solve the above problems, an object of the present invention is to provide a blue phosphor for a plasma display panel excellent in color purity and luminance retention.

In addition, an object of the present invention is to provide a method of manufacturing a plasma display panel having improved color purity and luminance retention by providing a fluorescent film formed from the blue phosphor.

In addition, an object of the present invention is to provide a plasma display panel having improved color purity by providing a fluorescent film formed from the blue phosphor.

In order to achieve the above object, the present invention

Provided is a blue phosphor for a plasma display panel represented by Formula 1 below:

<Formula 1>

(Ba _{1- xy} ) D _x MgAl ₁₀ O ₁₇ : Eu _y

Wherein D is Sr or Ca, 0.001 ≦ x ≦ 1.0, and 0.01 ≦ y ≦ 0.5.

In addition, in order to achieve the above object, the present invention

Forming a plurality of discharge spaces between the front panel and the rear panel provided to face each other; Forming a blue phosphor film by printing, drying, and firing a phosphor paste composition containing the blue phosphor particles represented by Chemical Formula 1, a solvent, and a resin binder in each of the discharge spaces; to provide.

In addition, in order to achieve the above other object, the present invention

Transparent front substrate; A rear substrate disposed in parallel with the front substrate; Light emitting cells partitioned by barrier ribs disposed between the front substrate and the rear substrate; Address electrodes extending over light emitting cells arranged in one direction; A rear dielectric layer covering the address electrodes; A red, green, and blue fluorescent film disposed in the light emitting cell; Sustain electrode pairs extending in a direction crossing the address electrode; A front dielectric layer covering the sustain electrode pairs; And a discharge gas in the light emitting cell; providing a plasma display panel in which the blue fluorescent film is formed from a blue phosphor represented by Chemical Formula 1.

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

The present invention relates to a blue phosphor for a plasma display panel represented by the following formula (1).

<Formula 1>

(Ba _{1- xy} ) D _x MgAl ₁₀ O ₁₇ : Eu _y

Wherein D is Sr or Ca, 0.001 ≦ x ≦ 1.0, and 0.01 ≦ y ≦ 0.5.

The content of D is preferably 2 to 10 parts by weight based on 100 parts by weight of the total phosphor. Since the color purity varies depending on the content of D, it is preferable to select a content that satisfies the desired color purity range.

The blue phosphor for a plasma display panel according to the present invention is characterized in that an Sr or Ca component is included in a BAM phosphor containing an Eu activator. Specifically, (Ba _1-xy ) Sr _x MgAl ₁₀ O ₁₇ : Eu _y or (Ba _{1 -xy} ) Ca _x MgAl ₁₀ O ₁₇ : Eu _y , and preferably (Ba _1-xy ) Sr _x MgAl ₁₀ O ₁₇ : Eu _y .

A continuous cryastalline metal oxide layer made of aluminum oxide (Al ₂ O ₃ ) may be formed on the surface of the phosphor. As described above, by coating the surface of the phosphor with a metal oxide such as Al ₂ O ₃ , stability due to thermal, ion sputtering, VUV, or the like can be improved.

In the method for preparing a phosphor according to the present invention, a Eu activator is added to a compound constituting the parent material, mixed, and then calcined at a temperature of 1,200 to 1,800 ° C. in a reducing atmosphere of H ₂ / N ₂ or CO / CO ₂ mixed gas. Powders can be prepared.

The compound constituting the parent material according to the present invention, for example, strontium or calcium compound, magnesium compound, aluminum compound, barium compound is mixed with the European compound, it is heat-treated in air at about 1,200 to 1,800 ℃ for about 10 hours And, this heat treatment product is prepared by calcining again in a reducing atmosphere for about 3 hours at a temperature of about 1,500 to 1,700 ℃. As the magnesium compound, a magnesium oxide such as MgO may be used, and the aluminum compound may be an aluminum oxide such as Al ₂ O _3, and the barium compound may be a barium oxide, such as BaCO ₃ , or the strontium compound. A strontium oxide such as SrCO ₃ , a calcium oxide such as CaO as the calcium compound, and a europium oxide such as Eu ₂ O ₃ may be representatively used as the europium compound. The reducing atmosphere may be a mixture of nitrogen and hydrogen at approximately 97: 3% by volume.

It is preferable to perform the said baking process in a reducing atmosphere, and it is more preferable to carry out especially in the mixed gas atmosphere of hydrogen and nitrogen. This gas atmosphere is for matching the reduction conditions of the europium which consists of divalent and trivalent.

It is preferable that the said fluorescent substance particle is a spherical particle, and particle diameter is 0.1 micrometer-2 micrometers.

The blue phosphor according to the present invention has improved luminance and luminescence properties when used for a display using VUV (vacuum ultraviolet light) as an excitation source, particularly for a PDP for a long time, and has excellent life performance, thereby maintaining the performance of the panel for a long time.

Hereinafter, a plasma display panel employing a fluorescent film formed from the phosphor according to the present invention will be described.

The plasma display panel of the present invention comprises a transparent front substrate; A rear substrate disposed in parallel with the front substrate; Light emitting cells partitioned by barrier ribs disposed between the front substrate and the rear substrate; Address electrodes extending over light emitting cells arranged in one direction; A rear dielectric layer covering the address electrodes; A red, green, and blue fluorescent film disposed in the light emitting cell; Sustain electrode pairs extending in a direction crossing the address electrode; A front dielectric layer covering the sustain electrode pairs; And a discharge gas in the light emitting cell. A plasma display panel comprising a phosphor film formed from the phosphor.

Referring to FIG. 1, the plasma display panel includes a front panel 210 and a rear panel 220.

The front panel 210 is a front substrate 211, the rear of the front substrate (more specifically, the sustain electrode pairs 214 disposed on the rear surface of the front substrate and extended across a row of light emitting cells 226, A front dielectric layer 215 and a passivation layer 216 covering the sustain electrode pairs are provided.

The rear panel 220 is disposed on the rear substrate 221 disposed in parallel with the front substrate, and in front of the rear substrate (more specifically, the front substrate 221a of the rear substrate) and intersects with the pair of sustain electrodes. Barrier ribs formed between the address electrodes 222 extending so as to extend, the rear dielectric layer 223 covering the address electrodes, and the front substrate and the rear substrate (more specifically, on the rear dielectric layer) to partition the light emitting cells 226 ( 224, and a red phosphor film 225a, a green phosphor film 225b, and a blue phosphor film made of red, green, and blue phosphors that emit visible light by receiving ultraviolet rays emitted from discharge gas by a sustain discharge. 225c).

According to an embodiment of the present invention, the blue fluorescent film 225b may be manufactured using a phosphor including (Ba _{1 -xy} ) D _x MgAl ₁₀ O ₁₇ : Eu _y . In order to facilitate printing, the phosphor for PDP of the present invention is mixed with a resin binder and a solvent to form a paste, and then printed by a screen method through a screen mesh prepared in advance, and dried and fired to obtain a fluorescent film. The drying temperature is suitably 100 to 150 ℃, firing temperature is carried out at 350 to 600 ℃, in particular about 450 ℃ to remove the organic matter of the paste. Ethyl cellulose or acrylic resin is used as the binder, and the binder content is 10 to 30 parts by weight based on 100 parts by weight of the phosphor. If the content of the binder is less than the above range, the bonding strength of the fluorescent film is lowered, and if the content of the binder exceeds the above range, the content of the phosphor in the fluorescent film is relatively decreased, thereby deteriorating characteristics such as color purity.

As the solvent, BCA (butyl carbitol) or terpineol (Terpineol) is used, and the content thereof is used based on 100 parts by weight of the phosphor based on 70 to 300 parts by weight. If the content of the solvent is less than the above range, the phosphor is not dispersed properly or the viscosity is high, and printing is difficult. If the content exceeds the above range, the phosphor content per unit volume is too low, which is undesirable because the luminance in the PDP panel is lowered.

The viscosity of the composition for forming a fluorescent film is 5,000 to 50,000 cps, particularly 20,000 cps. If the viscosity of the phosphor composition is less than 5,000 cps, the printing liquid flows into the next cell during printing, and thus the printing film may not be formed at the correct position. If the viscosity exceeds 50,000 cps, the viscosity is too high, so it is not preferable to print properly.

The compositions of the present invention may further add additives such as dispersants, plasticizers, antioxidants, leveling agents and the like, as required, all of which are known to the extent that they are commercially available to those of ordinary skill in the art. The amount of the additive is preferably added to about 0.1 to 10 parts by weight based on the total composition.

The blue fluorescent film uses the phosphor of Chemical Formula 1 according to the present invention, and both the red fluorescent film and the green fluorescent film may be used as long as they are commonly available in the manufacture of a plasma display panel .

The front substrate 211 and the rear substrate 221 is generally formed of glass, the front substrate is preferably a high light transmittance.

The address electrodes 222 disposed on the front surface 221a of the rear substrate and extending over the light emitting cells 226 are typically formed of a metal having high electrical conductivity, for example, Al. The address electrode 222 is used for the address discharge together with the Y electrode 312. The address discharge is a discharge for selecting the light emitting cells 226 to emit light, and the sustain discharge described later may occur in the light emitting cells 226 in which the address discharges are made.

The address electrodes 222 are covered by the rear dielectric layer 223. The rear dielectric layer 223 prevents charged particles from colliding with the address electrodes 222 and damaging the address electrodes during address discharge. The rear dielectric layer 223 is formed as a dielectric capable of inducing charged particles. Such dielectrics include PbO, B ₂ O ₃ , SiO _2, and the like.

A partition wall 224 partitioning the light emitting cells 226 is formed between the front substrate 211 and the rear substrate 221. The partition wall 224 is discharged between the front substrate 311 and the rear substrate 221. The space is secured, crosstalk between adjacent light emitting cells 226 is prevented, and the surface area of the phosphor layer 225 is increased. The partition wall 224 is formed of a glass component including elements such as Pb, B, Si, Al, and O, and a filler such as ZrO ₂ , TiO ₂ , and Al ₂ O ₃ as necessary. With Cr, Cu, Co, Fe, TiO ₂ Pigments such as may be included.

The sustain electrode pairs 214 extend in a direction crossing the direction in which the address electrode 222 extends over the light emitting cells 226 in a row. The sustain electrode pair 214 includes a pair of sustain electrodes 212 and 213 causing a sustain discharge, and the sustain electrode pair 214 is arranged in parallel on each other at predetermined intervals on the front substrate 211. It is. One of the sustain electrodes 212 and 213 is the X electrode 213 and the other is the Y electrode 212. The sustain discharge is caused by the potential difference between the X electrode 213 and the Y electrode 212.

Each of the X electrode 213 and the Y electrode 212 includes the transparent electrodes 213b and 212b and the bus electrodes 213a and 212a. However, in some cases, the X electrode 213 and the Y electrode 212 are common to the scan electrode only with the bus electrode without the transparent electrode. An electrode may be configured.

The transparent electrodes 213b and 212b are formed of a transparent material that is a conductor and does not prevent light emitted from the phosphor from advancing to the front substrate 211. Such materials include indium tin oxide (ITO). However, since the transparent conductor such as ITO has a large resistance, if the sustain electrode is composed only of the transparent electrode, the voltage drop in the longitudinal direction of the transparent electrode becomes large, and thus, the power required to drive the plasma display panel increases and the image is increased. Will slow down the response. In order to improve this, bus electrodes 213a and 212a formed of a metal having high electrical conductivity, for example, Ag, are disposed at the outer end of the transparent electrode.

The sustain electrodes 212 and 213 are covered by the front dielectric layer 215. The front dielectric layer 215 can prevent the adjacent X electrode 213 and the Y electrode 212 from being directly energized during the sustain discharge, and prevent the charged particles from damaging the sustain electrodes 212 and 213 by damaging them. there is a high transmittance is formed as a dielectric, as this dielectric material include _{PbO, B 2 O 3, SiO} 2.

A passivation layer 216 may be formed between the front dielectric layer 215. At this time, the protective film prevents charged particles from colliding with the front dielectric layer 215 during the sustain discharge, and emits a lot of secondary electrons during the sustain discharge. The protective film may be formed as MgO.

The discharge gas is filled in the light emitting cell 226. The discharge gas is, for example, a Ne-Xe mixed gas containing 5% to 10% of Xe, and at least a part of Ne may be replaced with He as necessary.

Hereinafter, preferred examples and comparative examples of the present invention are described. The following examples are described for the purpose of more clearly expressing the present invention, but the contents of the present invention are not limited to the following examples.

Example

Example 1

9.392 g BaCO _3, 34.665 g Al ₂ O _3, 2.741 g MgO, 1.196 g Eu ₂ O _3, 4.007 g SrCO ₃ , and 0.06 g AlF ₃ were wet mixed. The mixture was placed in an alumina crucible and fired in an electric furnace for 5 hours. The blue phosphor thus prepared was coated with Al ₂ O ₃ on the surface of the phosphor by a sol-gel method using an Al precursor to obtain a blue phosphor.

Comparative Example 1

9.392 g BaCO _3, 34.665 g Al ₂ O _3, 2.741 g MgO, 1.196 g Eu ₂ O ₃ , and 0.06 g AlF ₃ were wet mixed. The mixture was placed in an alumina crucible and fired in an electric furnace for 5 hours to obtain a blue phosphor.

evaluation

The blue light emission spectrum obtained by irradiating the vacuum ultraviolet-ray which used the excimer 146nm lamp with the fluorescent substance obtained by Example 1 and the comparative example 1 under 6.7 Pa or less vacuum conditions is shown in FIG.

In addition, the center wavelength, color coordinates, and relative luminance of the phosphors are shown in Table 1:

Center wavelength (nm) CIEx CIEy Relative luminance (%) Example 1 452.3 0.1452 0.0579 100 Comparative Example 1 454.2 0.1423 0.0721 127

Referring to Table 1, it can be seen that the color coordinate CIE y value is improved and the luminance value is improved.

2 shows the PL emission spectrum of the blue phosphor according to the present invention. Comparing the blue emission spectrum of the phosphor of the present invention with the conventionally used BAM phosphor, the PL emission spectrum measured using an excitation light of 147 nm can be seen that the center wavelength is shifted to the right.

3 and 4 show changes in color coordinate CIE y values and decreases in peak intensity of spectra during plastic deterioration and driving deterioration in order to evaluate deterioration characteristics due to Al ₂ O ₃ coating on the phosphor surface.

In order to evaluate the thermal stability of the phosphor, the phosphor was paste-formed with a vehicle and heat-treated at 500 ° C. for 1 hour, followed by using a 146 nm lamp and obtaining a blue emission spectrum obtained by irradiating vacuum ultraviolet rays. To evaluate.

Drive deterioration is to drive about 10 hours in the chamber containing Xe and to evaluate the change.

Referring to FIGS. 3 and 4, it can be seen that the lifetime of the phosphor is greatly improved during plastic degradation and driving degradation after coating as compared to before coating.

The blue phosphor according to the present invention has the advantage that the luminance and light emission characteristics are improved, and the lifespan performance is excellent for a long time in a display using a VUV (vacuum ultraviolet) excitation source, especially in a PDP, and the performance of the panel can be maintained for a long time. There is this.

Claims (7)

Blue phosphor for a plasma display panel represented by Formula 1 below: <Formula 1> (Ba _{1- xy} ) D _x MgAl ₁₀ O ₁₇ : Eu _y Wherein D is Sr or Ca, 0.001 ≦ x ≦ 1.0, and 0.01 ≦ y ≦ 0.5. A blue phosphor for a plasma display panel according to claim 1, wherein D is Sr. The blue phosphor of claim 1, wherein the phosphor has a continuous cryastalline metal oxide layer made of aluminum oxide (Al ₂ O ₃ ) on a surface thereof. The blue phosphor of claim 1, wherein the amount of D is 2 to 10 parts by weight based on 100 parts by weight of the total content. The blue phosphor for plasma display panel according to claim 1, wherein an average particle diameter of the phosphor particles is 0.1 µm to 2 µm. Forming a plurality of discharge spaces between the front panel and the rear panel provided to face each other; Printing, drying, and firing the phosphor paste composition containing the phosphor particles, the solvent, and the resin binder according to any one of claims 1 to 5, in each discharge space to form a blue phosphor film. Manufacturing method. Transparent front substrate; A rear substrate disposed in parallel with the front substrate; Light emitting cells partitioned by barrier ribs disposed between the front substrate and the rear substrate; Address electrodes extending over light emitting cells arranged in one direction; A rear dielectric layer covering the address electrodes; A red, green, and blue fluorescent film disposed in the light emitting cell; Sustain electrode pairs extending in a direction crossing the address electrode; A front dielectric layer covering the sustain electrode pairs; And a discharge gas in the light emitting cell. 10. The plasma display panel of claim 1, wherein the blue fluorescent film is formed from the blue phosphor of any one of claims 1 to 5.

Images