JP2005183125A - Plasma display panel and manufacturing method of same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PDP with high image quality restrained from deterioration in a passage of time, maintaining high light emission efficiency even in long termed operation, stable in a passage of time. <P>SOLUTION: A front panel 10 and a back panel 20 of the PDP 1 are arranged so as to face each other and sealed to form a discharge space 30 between them. A blue color phosphor layer 25B of the back panel 20 is composed of alkali earth metal aluminate phosphor, and a discharge gas composed of Ne-Xe (Xe: 10 to 30 vol.%) as main component, containing minute quantity (partial pressure of 0.05 Pa to 0.5 Pa) of O<SB>2</SB>is sealed in the discharge space 30 with a prescribed pressure (for example, in a level of 6.7×10<SP>4</SP>to 1.0×10<SP>5</SP>Pa). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a plasma display panel and a manufacturing method thereof, europium (Eu) -activated phosphor Ba _(1-x) As phosphors of the blue phosphor layer _{Sr y Eu z MgAl 10 O 17} (0. 05 ≦ x ≦ 0.40, 0 ≦ y ≦ 0.25, 0.05 ≦ z ≦ 0.20, (x−y) ≦ z), and the ratio of Xe in the discharge gas is 10 ( It relates to the composition of the discharge gas in the case where it is equal to or greater than (volume%).

Plasma display panels (hereinafter referred to as “PDP”) are roughly classified into direct current (DC) type and alternating current (AC) type, but at present, it is possible to adopt a fine cell structure, and high definition. The AC type suitable for conversion has become the mainstream.
In general, an AC type PDP has a structure in which a front panel and a back panel are arranged to face each other with a discharge space between them, and their outer peripheral portions are sealed. Among the components, the front panel has a structure in which display electrodes are arranged in a stripe shape on one main surface of the front substrate, and this is sequentially covered with a dielectric layer and a protective layer (MgO). .

On the other hand, the back panel has stripe-shaped data electrodes on one main surface of the back substrate, covered with a dielectric layer, and a partition wall extending in a direction parallel to the data electrodes. It has the structure which was made. The red (R), green (G), and blue (B) phosphor layers are formed separately for each groove on the wall surface of the groove formed by the dielectric layer and the partition walls.
The front panel and the back panel are arranged in the direction in which the display electrodes and the data electrodes arranged on each of the front panel and the rear panel intersect with each other, and are sealed with each other at the outer peripheral portions. Then, Ne—Xe-based or He—Xe-based mixed gas (discharge gas) is sealed in the discharge space formed between the panels by sealing.

  By the way, in the PDP, it is desired to improve the light emission efficiency, and as a measure therefor, research and development on the composition of the discharge gas, the composition of the phosphor used, and the like are being conducted. Among these, with respect to the composition of the discharge gas, research and development have been made to improve the ultraviolet light emission efficiency by increasing the Xe ratio in the composition to 10 (volume%) or more, thereby improving the light emission efficiency of the PDP.

On the other hand, with regard to the composition of the phosphor, especially a blue phosphor _{Ba (1-x) Sr y} Eu z MgAl 10 O 17 (0.05 ≦ x ≦ 0.40,0 ≦ y ≦ 0.25,0.05 ≦ z ≦ 0.20, (x−y) ≦ z) By using an Eu-activated phosphor having a composition, the wavelength conversion efficiency in the vacuum ultraviolet region is improved and the luminous efficiency of the PDP is improved.・ Development has been made. However, it is known that the wavelength conversion efficiency of the blue phosphor having the above composition deteriorates with time as the PDP is driven. In addition, such a phenomenon that the blue phosphor deteriorates with time is more remarkable when the content ratio of xenon (Xe) in the discharge gas is increased to 10 (volume%) or more in order to increase the ultraviolet light emission efficiency. Appears in

On the other hand, as a measure for suppressing deterioration of the phosphor over time in a PDP or the like, a technique in which gadolinium (Gd) is contained in the phosphor material at a ratio of 5 (mol%) or less (Patent Document 1). A technique for coating the surface of phosphor particles with a divalent metal silicate such as an alkaline earth metal (Patent Document 2), and further coating the surface of the phosphor particles with a film made of an oxide of antimony (Sb) Technology (Patent Document 3) has been developed.
Japanese Patent Publication No. 6-29418 JP 2000-34478 A JP-A-10-330746

  However, even if the techniques disclosed in Patent Documents 1 to 3 are used, it is difficult to sufficiently suppress the deterioration over time of the blue phosphor. That is, when the techniques of Patent Documents 1 and 2 are applied, the phosphor can be prevented from deterioration due to heat, but the effect of suppressing phosphor deterioration due to vacuum ultraviolet irradiation is sufficient. Can not get to. In order to obtain the effect by applying the technique of Patent Document 3, it is necessary to form a Sb oxide film with a uniform film thickness on the phosphor surface. It is practically difficult to form an oxide film with a uniform thickness. In addition, the technique of Patent Document 3 includes a problem that the chromaticity change and the emission intensity maintenance rate are in a contradictory relationship.

  The present invention has been made to solve the above-described problems, and suppresses deterioration of the phosphor over time, and maintains high light emission efficiency even when driving is performed over a long period of time, and is stable over time. It is an object of the present invention to provide a PDP having a high image quality and a manufacturing method thereof.

  The inventors of the present invention have found that in the course of research and development for solving the above problems, the deterioration of the blue phosphor accompanying the driving of the PDP has a close relationship with the atmosphere in the discharge space. That is, in the completed PDP, trace organic components at the manufacturing stage remain in the discharge space or various portions facing the discharge space, and the discharge space has a reducing atmosphere due to the presence of the organic component. In the blue phosphor having the above composition, an oxide of trivalent europium (Eu (III)) is segregated on and near the particle surface, and the presence of this oxide protects the phosphor from vacuum ultraviolet rays. However, due to the influence of the reducing atmosphere in the discharge space, the oxide is gradually destroyed from the particle surface over time. The blue phosphor having the above composition is affected by vacuum ultraviolet rays with the destruction of the oxide of Eu (III) in the vicinity of the particle surface and its wavelength, and the wavelength conversion efficiency decreases with time.

The present invention has been made in consideration of the temporal degradation mechanism of the Eu-activated phosphor discovered by the present inventors, and has the following characteristics.
(1) In a PDP in which a plurality of discharge cells are configured by a sealed container in which a discharge gas is filled in a discharge space, and a blue phosphor layer is formed in a partial region facing the discharge space, the blue phosphor layer _{is, Ba (1-x) Sr} y Eu z MgAl 10 O 17 (0.05 ≦ x ≦ 0.40,0 ≦ y ≦ 0.25,0.05 ≦ z ≦ 0.20, (x-y) ≦ z), the discharge gas contains Xe in a ratio of 10% by volume or more, and 0.05 (Pa) or more and 0.5 (Pa). An oxidizing gas is contained at the following partial pressure.

(2) The PDP according to (1) is characterized in that the Eu-activated phosphor has a composition that satisfies a relationship of 0 <y ≦ 0.25.
(3) In the PDP according to the above (1) or (2), the oxidizing gas is oxygen (O ₂ ).
In addition, in the PDP using O ₂ as the oxidizing gas in this way, each residual such as hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ) and the like having a buffering effect on O ₂ . It is desirable that the amount be set to 1/10 or less of the O ₂ amount in the discharge space.

(4) A method of manufacturing a PDP according to the present invention has an interior discharge space, and, Ba _(1-x) in the partial region of the wall surface facing the discharge space _{Sr y Eu z MgAl 10 O 17} (0 .05 ≦ x ≦ 0.40, 0 ≦ y ≦ 0.25, 0.05 ≦ z ≦ 0.20, (xy) ≦ z) Blue phosphor layer made of Eu-activated phosphor Are exhausted from the discharge space to the container, and after the exhaust step, N ₂ purge is performed by introducing nitrogen (N ₂ ) into the discharge space, and impurities are N _2. A purging step for purifying the inside of the discharge space by alternately repeating a plurality of times of vacuum purging with N ₂ introduced by the purging, and after the cleaning step, Oxidation in an amount such that the partial pressure at 0.05 to 0.5 (Pa) Gas, the ratio is characterized in that it comprises a gas introduction step of introducing the mixed gas containing the amount of Xe to be 10 (vol%) or more.

(5) In the method for producing a PDP according to the above (4), the composition of the Eu-activated phosphor constituting the blue phosphor layer satisfies a relationship of 0 <y ≦ 0.25.
(6) In the method for producing a PDP according to (4) or (5), O ₂ is used as an oxidizing gas in the mixed gas in the gas introduction step.
When O ₂ is used as the oxidizing gas in this way, in the cleaning step and the gas introduction step, the residual amounts of H ₂ , CO, and CO ₂ in the discharge space are set to 1 with respect to the O ₂ amount. / 10 or less is desirable.

(7) In the method for producing a PDP according to the above (4) to (6), in the cleaning step, N ₂ having a purity of 99.999 (%) or higher is introduced until the pressure becomes 0.01 (MPa) or higher. N ₂ purge is performed, and the inside of the discharge space is evacuated to 10 ⁻³ (Pa), vacuum purge is performed to remove N ₂ and impurities, and the discharge space is cleaned with both purges. And

(8) In the PDP manufacturing method according to any one of (4) to (7), in the cleaning step, a discharge is generated in the discharge space during the N ₂ purge.

In the PDP according to the present invention, the discharge gas filled in the discharge space contains 10 (volume%) or more of Xe in a ratio, so that the efficiency of UV generation by driving discharge is high, and further, as a blue phosphor _{Ba (1-x) Sr y} Eu z MgAl 10 O 17 (0.05 ≦ x ≦ 0.40,0 ≦ y ≦ 0.25,0.05 ≦ z ≦ 0.20, (x-y) ≦ z ), The wavelength conversion efficiency in the vacuum ultraviolet region is high. Therefore, the PDP of the present invention has high luminous efficiency from the initial driving stage.

  Moreover, in the PDP according to the present invention, since the oxidizing gas is contained in the discharge gas at a partial pressure of 0.05 (Pa) or more, the trivalent segregated on the surface of the blue phosphor particles and in the vicinity thereof. It is difficult to destroy the Eu oxide, and the blue phosphor is prevented from being deteriorated by the irradiation of vacuum ultraviolet rays. That is, in the conventional PDP in which the discharge gas does not contain an oxidizing gas at a partial pressure of 0.05 (Pa) or more, the blue phosphor is affected by the reducing atmosphere in the discharge space. In the PDP of the present invention, the trivalent Eu oxide on the particle surface and its vicinity is gradually destroyed over time, and as a result, it is deteriorated with time by being irradiated with vacuum ultraviolet rays. Since the oxidizing gas is contained in the discharge gas at a partial pressure of 0.05 (Pa) or more, the trivalent Eu oxide segregated on the surface of the blue phosphor particles and in the vicinity thereof has a long time. It is hard to be destroyed by the progress, and the deterioration of the blue phosphor over time is suppressed.

  In the PDP according to the present invention, since the partial pressure of the oxidizing gas in the discharge gas is set to 0.5 (Pa) or less, the light emission efficiency of the panel is lowered to a level that is substantially problematic. There is no. That is, in the PDP, if the discharge gas contains a larger amount of oxidizing gas, the blue phosphor can be prevented from deteriorating over time, but the discharge electron temperature is lowered and the ultraviolet light emission efficiency is lowered. Moreover, since the vacuum ultraviolet rays generated by the discharge are absorbed by the oxidizing gas, the light emission efficiency of the panel is lowered. On the other hand, in the PDP according to the present invention, since the partial pressure of the oxidizing gas is set to 0.5 (Pa) or less, a decrease in light emission efficiency to a substantial level due to the above action is suppressed.

  Further, in the PDP, MgO is usually used for the protective layer. In this case, if the partial pressure of the oxidizing gas in the discharge gas is larger than 0.5 (Pa), the deterioration of MgO with time is remarkable. Thus, the discharge start voltage as the PDP is inevitably increased. Therefore, in the PDP according to the present invention, in consideration of such points, the partial pressure of the oxidizing gas in the discharge gas is set to 0.5 (Pa) or less.

Therefore, the PDP according to the present invention suppresses deterioration of the blue phosphor over time, maintains high luminous efficiency even when driven for a long time, and has high image quality that is stable over time.
As specific oxidizing gas, oxygen (O ₂ ), ozone (O ₃ ), oxygen radical (O ^* ), carbon dioxide (CO ₂ ) can be used.
Further, in the PDP manufacturing method according to the present invention, the partial pressure in the discharge space is 0.05 (Pa) or more to the discharge space cleaned after the sealing step and the cleaning step. Since there is a gas introduction step for introducing a mixed gas containing an oxidizing gas in an amount of 0.5 (Pa) or less and Xe having a ratio of 10 (volume%) or more, the time-dependent blue phosphor It is possible to reliably manufacture a PDP having a high image quality that is stable over time, while suppressing deterioration and maintaining high luminous efficiency even when driven for a long period of time.

In the following, the best mode for carrying out the present invention will be described with an example. Note that the embodiment described below is merely an example for carrying out the present invention, and the present invention is not limited thereto.
1. Configuration of Panel 1 An AC type PDP (hereinafter simply referred to as “PDP”) 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view (partial cross-sectional view) of a main part of a PDP 1 and shows a part of a display area in a panel.

As shown in FIG. 1, the PDP 1 has a structure in which a front panel 10 and a rear panel 20 are arranged to face each other with a gap. The gap between the front panel 10 and the back panel 20 is partitioned into a plurality of discharge spaces 30 by a plurality of strips 24 protruding on the main surface of the back panel 20.
In the front panel 10, a plurality of scan electrodes 12 and a plurality of sustain electrodes 13 are alternately formed on one main surface of the front substrate 11, and the surface of the front substrate 11 on which these electrodes 12 and 13 are formed is The dielectric layer 14 and the protective layer 15 are sequentially covered. Here, the scan electrode 12 has a laminated structure of the transparent electrode 12a and the bus line 12b, and similarly, the sustain electrode 13 has a laminated structure of the transparent electrode 13a and the bus line 13b. The transparent electrodes 12a and 13a have, for example, a thickness of 0.1 (μm) and a width of 150 (μm) made of ITO (Indium Tin Oxide), and the bus lines 12b and 13b have, for example, It has a thickness of 7 (μm) and a width of 95 (μm) made of a metal material such as silver (Ag).

The distance between the scan electrode 12 and the sustain electrode 13 is set to, for example, approximately 80 (μm). The dielectric layer 14 formed so as to cover the electrodes 12 and 13 is a layer having a thickness of 30 (μm) made of low melting point lead glass, for example, and the protective layer 15 is made of MgO, for example. A layer having a thickness of about 1.0 (μm).
On the other hand, the back panel 20 has a plurality of data electrodes 22 formed on one main surface of the back substrate 21, and the surface of the front substrate 21 on which the data electrodes 22 are formed is covered with a dielectric layer 23. Further, a partition wall 24 is erected at a position between adjacent data electrodes 22 on the surface of the dielectric layer 23. Here, the data electrodes 22 are made of a metal material such as Ag and have a thickness of 5 (μm) and a width of 60 (μm), and are arranged in parallel at a pitch of about 150 (μm). . The dielectric layer 23 is made of, for example, a material in which low melting point lead glass is mixed with TiO and has a thickness of 30 (μm).

The partition walls 24 are formed according to the pitch of the data electrodes 22 and have a size of about 150 (μm) in height and about 40 (μm) in width, for example.
In the back panel 20, a phosphor layer 25 is formed on a wall surface portion of a groove formed by a pair of adjacent barrier ribs 24 and a dielectric layer 23. The phosphor layer 25 is divided into a red (R) phosphor layer 25R, a green (G) phosphor layer 25G, and a blue (B) phosphor layer 25B for each groove. As each phosphor constituting each phosphor layer 25R, 25G, 25B, for example, the following is used.

Red (R) phosphor; (Y, Gd) BO ₃ : Eu
Green (G) phosphor; Zn ₂ SiO ₄ : Mn
Blue (B) _{phosphor; Ba (1-x) Sr} y Eu z MgAl 10 O 17: Eu
However, among the compositions of the above phosphors, in the alkaline earth metal aluminate phosphor used as the blue phosphor, 0.05 ≦ x ≦ 0.40, 0 ≦ y ≦ 0.25, 0. The relationship of 05 ≦ z ≦ 0.20 and (xy) ≦ z is satisfied.

The PDP 1 has a configuration in which a front panel 10 and a rear panel 20 are arranged to face each other and sealed between each other outer peripheral portion to form a sealed container, and a discharge space formed between the panels 10 and 20. 30.
In the discharge space 30, a Ne—Xe (Xe: 10 to 30% by volume) -based mixed gas (discharge gas) has a predetermined pressure (for example, about 6.7 × 10 ^{4 to} 1.0 × 10 ⁵ Pa). It is enclosed with. In the PDP1 according to the present embodiment, as a component of the discharge gas, O ₂ traces (partial pressure within 0.5Pa following range of 0.05 Pa) it is contained. Further, with the inclusion of O ₂ in the discharge gas, the partial pressures of H ₂ , CO, and CO ₂ in the discharge space 30 are set to be 1/10 or less of the partial pressure of O ₂ . This is to suppress the buffering effect on O ₂ under vacuum ultraviolet irradiation.

In the PDP 1 configured as described above, each region where the scan electrode 12, the sustain electrode 13, and the data electrode 22 intersect with the discharge space 30 therebetween corresponds to a discharge cell for image display. Further, the pixel pitch in the PDP 1 is set to about 1080 (μm) and about 360 (μm), respectively, with respect to the direction along the data electrode 22 and the direction along the scan electrode 12 and the sustain electrode 13, for example. .
2. Advantages of PDP 1 The advantages of the PDP 1 having the above configuration over the conventional PDP will be described with reference to FIGS. FIG. 2 is a cross-sectional view schematically showing a particle cross section of an alkaline earth metal aluminate phosphor (hereinafter simply referred to as “Eu-activated phosphor”) used as a blue phosphor in the PDP 1.

  As shown in FIG. 2, in the Eu-activated phosphor, Eu (III) oxide is segregated on the surface and in the vicinity thereof in the manufactured state. In the Eu activated phosphor in which this Eu (III) oxide (hereinafter referred to as “Eu (III) oxide”) is segregated on the surface and in the vicinity thereof, vacuum ultraviolet irradiation is performed by the Eu (III) oxide. The influence on the phosphor due to is suppressed.

By the way, in the conventional PDP, as described above, a trace amount of organic components in the manufacturing stage remain in the discharge space 30, and the presence of this organic component has a reducing atmosphere. The Eu (III) oxide segregated on and near the surface of the Eu-activated phosphor of FIG. 2 is gradually destroyed over time due to the influence of the reducing atmosphere. With
As a result, the phosphor is deteriorated by being affected by the irradiation of vacuum ultraviolet rays.

On the other hand, in the PDP 1 according to the present embodiment, the discharge gas sealed in the discharge space 30 contains O ₂ at a partial pressure of 0.05 (Pa) or more. This Eu (III) oxide is maintained regardless of the passage of time, and the phosphor is not deteriorated by the influence of irradiation with vacuum ultraviolet rays. Further, the PDP 1, H _2, CO in the discharge space 30, the partial pressure of CO _2, since the set to be 1/10 or less of the partial pressure of O _2, to O ₂ to achieve the above effects Therefore, it is possible to stably suppress deterioration of the Eu-activated phosphor without causing a problem of the buffer effect.

Further, in the PDP 1, since the partial pressure of O ₂ in the discharge gas is regulated to 0.5 (Pa) or less, a decrease in the light emission efficiency of the panel is efficiently suppressed. That is, if O ₂ exceeding 0.5 (Pa) is contained in the discharge gas, it is desirable from the viewpoint of suppressing deterioration with time of the Eu-activated phosphor. Luminous efficiency is reduced, vacuum ultraviolet rays generated by discharge are absorbed by O ₂ , and deterioration of the protective layer 15 made of MgO is significant over time, leading to a reduction in luminous efficiency of the panel. become.

On the other hand, in the PDP 1, since the partial pressure of O ₂ in the discharge gas is regulated to 0.5 (Pa) or less, the panel does not substantially reduce the light emission efficiency and has high image quality. Can be maintained over time.
Further, in the PDP 1, the ratio of Xe in the discharge gas is set within a range of 10 to 30 (volume%), and the blue phosphor layer 25B is composed of the Eu-activated phosphor having the above composition. Since high ultraviolet generation efficiency by driving discharge and high wavelength conversion efficiency in the vacuum ultraviolet region can be obtained, the light emission efficiency is high.
3. Method for Manufacturing PDP 1 Next, a method for manufacturing PDP 1 will be described with reference to FIG.

  As shown in FIG. 3A, a front panel 10 provided with a vent 101 for introducing exhaust gas and discharge gas and a rear panel 20 are arranged to face each other, and the outer peripheral portions of each other are frit glass or the like. Seal with. Here, the formation of the front panel 10 and the formation of the back panel 20 can be performed using a conventional method for manufacturing a PDP, and thus the description thereof is omitted here. However, the formation of the blue phosphor layer 25B in the back panel 20 will be described later.

Next, as shown in FIG. 3B, a vent pipe 61 is connected to the vent hole 101 provided in the front panel 10, and using this, the internal pressure of the discharge space 30 is about 10 ⁻³ (Pa). Evacuate until it becomes (vacuum purge). Here, the panel may be fired in parallel.
Note that the timing of starting evacuation is preferably the time when the temperature of the frit glass at the time of sealing in FIG. 3A is lower than the softening point. However, this is not the case when the atmosphere around the panel is a vacuum.

Subsequently, as shown in FIG. 3C, 99.999 (%) or more of N ₂ is introduced into the discharge space 30 after being evacuated until the pressure becomes 0.01 (MPa) or more. (N ₂ purge). At this time, aging may be performed by generating a discharge in the discharge space 30 using each electrode (not shown) of the front panel 10 and the back panel 20. Further, in purging in FIG. 3C, Ne or Ne—Xe mixed gas may be used instead of N ₂ .

In the present embodiment, the vacuum purge in FIG. 3B and the N ₂ purge in FIG. 3C are alternately repeated a plurality of times to sufficiently clean the inside of the discharge space 30. One guideline for this cleaning is until the partial pressures of H ₂ , CO, and CO ₂ in the discharge space 30 become 1/10 or less of the partial pressure of O _{2 in} the PDP 1 after completion. is there.
As shown in FIG. 3D, after performing the above-described cleaning and exhausting in FIG. 3B, Ne—Xe-based gas or He—Xe-based gas and O ₂ as an oxidizing gas are used. The mixed gas (discharge gas) contained is introduced through the vent pipe 61. The amount of the mixed gas introduced is such that the pressure in the discharge space 30 is in the range of 6.7 × 10 ^{4 to} 1.0 × 10 ⁵ (Pa), for example. Here, the ratio of Xe in the discharge gas is in the range of 10 to 30 (volume%) as described above, and the content of O ₂ is 0.05 (Pa) or more in partial pressure to 0.5. (Pa) is an amount that is less than or equal to.

Finally, although not shown in the figure, the vent tube 61 is removed and then provided on the front panel 10 while being careful not to leak the discharge gas to the outside or conversely enter the discharge space 30 from the outside. The PDP 1 is completed by closing the vent hole 101 formed.
4). Formation of Blue Phosphor Layer 25B The following description supplements the formation of the blue phosphor layer 25B in the method for manufacturing the PDP 1 shown in FIG.

4-1. Preparation of Eu-activated phosphor First, in preparation of Eu-activated phosphor, as a material to be an aluminum (Al) source, high purity (purity 99% or more) aluminum hydroxide, aluminum nitrate, aluminum halide, etc. An aluminum compound that becomes alumina by firing can be used. It is also possible to directly use high-purity (purity 99% or more) alumina (the crystal form may be α alumina or intermediate alumina).

Use barium compounds that become barium oxide by firing, such as barium hydroxide with a high purity (99% or more purity), barium carbonate, barium nitrate, barium halide, barium oxalate, etc. Can do. In addition, barium oxide having high purity (purity 99% or more) can also be used directly.
Use calcium compounds that become calcium oxide when fired, such as high-purity (purity 99% or more) calcium hydroxide, calcium carbonate, calcium nitrate, calcium halide, calcium oxalate, etc. Can do. In addition, calcium oxide having high purity (purity 99% or more) can also be used directly.

  As a strontium (Sr) source material, a high purity (purity 99% or more) strontium hydroxide, strontium carbonate, strontium nitrate, strontium halide, strontium oxalate, or the like is used, and a strontium compound that becomes strontium oxide by firing is used. Can do. Further, strontium oxide having high purity (purity 99% or more) can also be used directly.

A magnesium compound that becomes MgO by firing, such as magnesium hydroxide, magnesium carbonate, magnesium nitrate, magnesium halide, magnesium oxalate, etc., having high purity (purity 99% or more) is used as the material for the magnesium (Mg) source. it can. In addition, magnesium oxide having high purity (purity 99% or more) can also be used directly.
Use europium compounds that become europium oxide upon firing, such as europium hydroxide, europium carbonate, europium nitrate, europium halide, europium oxalate, etc. Can do. Further, europium oxide having high purity (purity 99% or more) can also be used directly.

The formulation of the material of each specific _{phosphors, Ba (1-x) Sr} y Eu z MgAl 10 O 17: Eu (x = 0.02, y = 0.01, z = 0.01) The composition of the An example of the production of the alkaline earth metal aluminate phosphor is shown below.
BaCO ₃ : 0.80 (mol)
SrCO ₃ : 0.10 (mol)
Eu ₂ O ₃ : 0.05 (mol)
MgCO ₃ : 1.00 (mol)
Al ₂ O ₃ : 5.00 (mol)
For mixing each phosphor raw material, a V-type mixer, a stirrer, or the like that is generally used in industry can be used, and a ball mill, a vibration mill, a jet mill, or the like having a pulverizing function can also be used.

As described above, a mixed powder of Eu-activated phosphors having an average particle size of 2 (μm) is obtained.
In the method for forming a phosphor according to the present embodiment, the supply of hydrogen (H ₂ ) is stopped when the temperature of the mixed powder firing step is lowered, and an inert gas atmosphere (for example, an atmosphere containing only N ₂ ) is set. . This point is different from the conventional phosphor forming method.
The mixed powder of the phosphor material is weighed as described above. Then, reduction firing is performed for 4 (hr.) At a temperature of 1500 (° C.) in a mixed gas of nitrogen and hydrogen (for example, a mixed gas of N ₂ : 96% and H ₂ : 4%) using a firing furnace.

Here, in the firing process, the maximum temperature of 1500 (° C.) is reached when about 7 (hr.) Has elapsed after the start of firing. Then, 4 (hr.) Firing is performed while maintaining this maximum temperature, and then the atmosphere is set to an inert gas (N ₂ only). Under this atmosphere, the temperature is lowered over about 10 (hr.).
In the present embodiment, an example in which the firing temperature is set to 1500 (° C.) and the firing time is 4 (hr.) Has been described, but naturally, the firing temperature, the firing time, and the like depend on the particle size of the raw material and the flux ( It goes without saying that appropriate adjustment is necessary to match the optimum value depending on the amount of AlF ₃ ) and the crystallinity of the raw material alumina.

Further, in the present embodiment, the case where the mixed powder is reduced and fired has been described. However, the powder may be baked once in the air before the reduction and baking to obtain a fired powder.
As described above, the Eu-activated phosphor used as a component of the blue phosphor layer 25B in the PDP 1 is manufactured.
4-2. Formation of Blue Phosphor Layer 25B Next, a method for forming the blue phosphor layer 25B using the formed Eu-activated phosphor will be described below.

  To the Eu-activated phosphor 30 (mass%), ethyl cellulose (molecular weight 200,000) 4.5 (mass%) and a solvent (for example, butyl carbitol acetate) 65.5 (mass%) are mixed. Then, the phosphor ink for the blue phosphor layer 25B is prepared. At this time, the viscosity of the phosphor ink is adjusted to, for example, about 2.0 to 6.0 (Pa · s) in order to ensure that the phosphor ink can adhere to the partition wall 24. deep.

The phosphor ink thus produced is applied to the wall surface of the groove formed by the partition wall 24 and the dielectric layer 23 using, for example, the meniscus method. Then, the phosphor ink is dried and baked (for example, at 500 ° C. for 10 min.) To form the blue phosphor layer 25B.
In addition, about the component of each mixed material used when producing fluorescent substance ink, it is not limited to the said component. Also, the method for applying the phosphor ink to the wall surface of the groove is the meniscus method in the above description, but is not limited thereto. For example, it is of course possible to use a line jet method or the like.

The formation method of the red phosphor layer 25R and the green phosphor layer 25G is basically the same as the formation method of the blue phosphor layer 25B except that the phosphor material used is different. Therefore, the detailed description about this is abbreviate | omitted.
5). Superiority Confirmation Experiment Hereinafter, an experiment conducted to confirm the superiority of the PDP 1 according to the present embodiment will be described.

5-1. Confirmation of phosphor degradation due to vacuum ultraviolet irradiation First, the change in degradation of the Eu-activated phosphor due to vacuum ultraviolet irradiation was observed based on the partial pressure of O ₂ in the discharge gas, and the results are shown in FIG. Here, relative brightness was used in this experiment as an index of deterioration of the Eu-activated phosphor. In addition, as a PDP model used in the experiment, a Ne—Xe-based mixed gas (Xe concentration: 10% by volume) containing Eu-activated phosphor powder having the above composition inside and containing O ₂ is used. ) Was used. The hermetic container was irradiated with vacuum ultraviolet rays having a wavelength of 147 (nm), and the relative luminance was measured to evaluate the deterioration of the phosphor. Incidentally, O ₂ partial pressure in the mixed gas to be filled into the sealed containers were each model varied 6 levels between 0 to 1.0 (Pa).

As shown in FIG. 4, in the model in which the partial pressure of O ₂ in the mixed gas is 1.0 (Pa), the relative luminance does not decrease over time, but 0 to 0.5 ( For the PDP model of Pa), the relative luminance decreases with the passage of time. Of the five models having an O ₂ partial pressure of 0 to 0.5 (Pa), the mixed gas did not contain any O ₂ , that is, the relative luminance of the model having a partial pressure of 0 (Pa). The decrease was remarkable, and the relative luminance at the time when 500 (min.) Elapsed had decreased to 90 (%).

On the other hand, in the model in which the partial pressure of O ₂ in which only a slight amount of O ₂ is contained in the mixed gas is 0.05 (Pa), the relative luminance at the time when 500 (min.) Has elapsed is 95 (% ) Was maintained.
Therefore, it can be seen from this result that deterioration of the Eu-activated phosphor over time is suppressed by adding O ₂ at a partial pressure of 0.05 (Pa) or more in the mixed gas. That is, by including O ₂ at a partial pressure of 0.05 (Pa) or more, the discharge space in the PDP becomes oxidizing, and the Eu-activated phosphor is deteriorated to a level that does not substantially affect the image quality. Is suppressed.

5-2. Confirmation of deterioration of protective layer due to inclusion of O ₂ Next, it was confirmed how the deterioration of the protective layer 15 made of MgO changes depending on the difference in O ₂ partial pressure in the discharge gas, and the result is shown in FIG. . Here, in this confirmation experiment, the same PDP as the embodiment shown in FIG. 1 was used as the PDP model, and the change in the discharge start voltage was measured as an index indicating the deterioration of the protective layer 15. In this experiment, the discharge start voltage required to make the amount of infrared rays generated simultaneously with the vacuum ultraviolet rays from Xe due to discharge become a constant value was confirmed and plotted in FIG.

As shown in FIG. 5, the increase in discharge start voltage with time increases as the O ₂ partial pressure in the discharge gas increases. That is, O ₂ in the discharge gas causes the protective layer 15 made of MgO to deteriorate. In particular, as shown in FIG. 5, the deterioration becomes remarkable at a partial pressure of 1.0 (Pa).
Therefore, it can be said that it is desirable that the O ₂ partial pressure in the discharge gas be 0.5 (Pa) or less from the viewpoint of suppressing deterioration of the protective layer 15.

5-3. Consideration about the partial pressure of O _{2 in} the discharge gas From the results of the above two confirmation experiments, the partial pressure of O ₂ in the discharge gas ranges from 0.05 (Pa) to 0.5 (Pa). It is desirable to be inside. That is, from the viewpoint of suppressing the temporal deterioration of the Eu-activated phosphor, it is desirable that the O ₂ partial pressure in the discharge gas is 0.05 (Pa) or more, and the protective layer 15 is deteriorated with time. From the viewpoint of suppressing the above, it is desirable that the O ₂ partial pressure in the discharge gas is 0.5 (Pa) or less.

Moreover, although the result of the confirmation experiment is not shown, when the O ₂ partial pressure in the discharge gas is 0.5 (Pa) or more, the electron temperature of the discharge is lowered and the ultraviolet light emission efficiency is lowered. Further, since the vacuum ultraviolet rays generated by the discharge are absorbed by the oxidizing gas, the light emission efficiency of the panel is lowered to a level that causes a problem in practical use.
Note that the partial pressure of O ₂ in the PDP 1, the O ₂ partial pressure remained in the discharge space in a conventional PDP is in a range clearly have differences. The O ₂ partial pressure remaining in the discharge space of the conventional PDP is of a level that cannot be measured.
6). Other Matters The PDP 1 according to the embodiment of the present invention is an example used for explaining the configuration and operation of the present invention, and it is obvious that the present invention is not limited thereto. .

For example, the composition of the Eu-activated phosphors of the blue phosphor layer 25B, as indicated _{above, Ba (1-x) Sr} y Eu z MgAl 10 O 17 (0.05 ≦ x ≦ 0.40, Since 0 ≦ y ≦ 0.25, 0.05 ≦ z ≦ 0.20, and (x−y) ≦ z), strontium (Sr) may or may not be contained in the composition.
In the PDP 1, O ₂ is used as an example of the oxidizing gas, but O ₃ , O ^* , CO ₂ or the like can also be used. However, when these oxidizing gases are contained, it is desirable to regulate the content (partial pressure) of a substance having a buffering effect with these oxidizing gases in conjunction with the oxidizing gases. For example, when CO ₂ is used as the oxidizing gas, it is desirable to set the partial pressure of H ₂ to 1/10 or less of the partial pressure of CO ₂ .

  Further, the configuration of the PDP 1 according to the above-described embodiment is also an example, and it is not always necessary to have a configuration in which the front panel 10 and the back panel 20 are arranged to face each other. The discharge space is filled with a discharge gas containing an oxidizing gas, 10 (volume%) or more of Xe, and 0.05 (Pa) or more and 0.5 (Pa) or less of an oxidizing gas, The present invention can be applied to a PDP in which a blue phosphor layer 25B made of Eu-activated phosphor shown in FIG.

  The PDP according to the present invention is effective for realizing a display device such as a computer or a television, in particular, a display device having high definition and high brightness and stable image quality over time.

It is a principal part perspective view (partial cross section figure) which shows PDP1 which concerns on embodiment of this invention. It is typical sectional drawing which shows the structure of the blue fluorescent substance particle (alkaline earth metal aluminate fluorescent substance particle) used by PDP1. It is process drawing which shows the process which concerns on the introduction of discharge gas from the panel sealing in the manufacture process of PDP1. Reduction of O ₂ partial pressure and the panel brightness is a characteristic diagram showing the relationship between (the deterioration of the blue phosphor). O ₂ partial pressure and is a characteristic diagram showing the relationship between the firing voltage (deterioration of MgO).

Explanation of symbols

1. PDP
10. Front panel 12. Scan electrode 13. Sustain electrode 15. Protective layer 20. Rear panel 22. Data electrode 25. Phosphor layer 30. Discharge space

Claims (8)

In a plasma display panel in which a plurality of discharge cells are constituted by a sealed container filled with a discharge gas in a discharge space, and a blue phosphor layer is formed in a partial region facing the discharge space.
The blue phosphor _{layer, Ba (1-x) Sr} y Eu z MgAl 10 O 17 (0.05 ≦ x ≦ 0.40,0 ≦ y ≦ 0.25,0.05 ≦ z ≦ 0.20, (X−y) ≦ z) composed of an Eu-activated phosphor having a composition represented by
The plasma display panel, wherein the discharge gas contains Xe at a ratio of 10% by volume or more and an oxidizing gas at a partial pressure of 0.05 Pa to 0.5 Pa. The plasma display panel according to claim 1, wherein the composition of the Eu-activated phosphor satisfies a relationship of 0 <y ≦ 0.25. The plasma display panel according to claim 1, wherein the oxidizing gas is O ₂ . It has an internal discharge space, and, in a partial region of the wall surface facing the discharge space _{Ba (1-x) Sr y} Eu z MgAl 10 O 17 (0.05 ≦ x ≦ 0.40,0 ≦ y ≦ 0.25, 0.05 ≦ z ≦ 0.20, (xy) ≦ z) with respect to the container in which the blue phosphor layer made of the Eu-activated phosphor is formed, remains from the discharge space. An exhaust step for exhausting the gas;
After it said pumping step, the relative discharge space, and N ₂ purge performed by introducing N _2, the discharge space and a vacuum purge is repeated a plurality of times for exhausting with N ₂ was introduced impurity in the N ₂ purge A cleaning step for purifying the inside,
After the cleaning step, with respect to the discharge space, an oxidizing gas in an amount such that the partial pressure in the discharge space is 0.05 Pa or more and 0.5 Pa or less, and an amount of Xe in which the ratio is 10 vol% or more. And a gas introduction step of introducing a mixed gas including: a method of manufacturing a plasma display panel. The method for manufacturing a plasma display panel according to claim 4, wherein the composition of the Eu-activated phosphor constituting the blue phosphor layer satisfies a relationship of 0 <y ≦ 0.25. The method for manufacturing a plasma display panel according to claim 4, wherein the oxidizing gas contained in the mixed gas is O ₂ . In the cleaning step, N ₂ purge is performed by introducing N ₂ having a purity of 99.999% or more until it becomes 0.01 MPa or more, and the discharge space is exhausted until 10 ⁻³ Pa is reached. The method of manufacturing a plasma display panel according to claim 4, wherein a vacuum purge is performed. The method for manufacturing a plasma display panel according to any one of claims 4 to 7, wherein in the cleaning step, discharge is generated in the discharge space during N ₂ purge.

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