JP2004269869A - Plasma display panel and method for producing phosphor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phosphor of which the degradation of light emission intensity is low, and to provide a plasma display panel (PDP), using the phosphor. <P>SOLUTION: A method for producing the phosphor comprises producing the phosphor of an aluminate salt to which at least one of Eu and Mn is added as an activator to be used as an emission center and in which a multicomponent oxide containing at least one of Ba, Ca, Sr, and Mg is used as a host crystal, wherein a mixed raw material for the phosphor is calcined in a reducing atmosphere at least once or more times, and then treated in an oxygen plasma atmosphere after completion of the last treatment in the reducing atmosphere. Thus, oxygen defect of the host crystal caused by treatment in the reducing atmosphere is restored by being treated in the oxygen plasma atmosphere, so that the phosphor having high light emission intensity is obtained. The PDP having the high light emission intensity and the low deterioration of the emission intensity is obtained by using the phosphor. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a plasma display device and a method of manufacturing a phosphor, and particularly, the phosphor is suitable for an image display device represented by a plasma display device, a rare gas discharge lamp, and a lighting device represented by a high-load fluorescent lamp. It can be used for

  2. Description of the Related Art In recent years, among color display devices used for image display of computers, televisions, and the like, plasma display devices have attracted attention as color display devices that can be large, thin, and lightweight.

  The plasma display device performs full-color display by additively mixing three primary colors (red, green, and blue). In order to perform this full color display, the plasma display device is provided with a phosphor layer that emits each of the three primary colors red, green and blue. Then, in the discharge cells of the plasma display device, ultraviolet rays having a wavelength of 200 nm or less are generated by the discharge of the rare gas, and the ultraviolet rays excite the phosphors of each color to generate visible light of each color.

Examples of the phosphor of each color include (Y, Gd) BO ₃ : Eu ³⁺ , Y ₂ O ₂ S: Eu ³⁺ , which emits red light, and (Ba, Sr, Mg) O · aAl ₂ which emit green light. O ₃ : Mn ²⁺ , Zn ₂ SiO ₄ : Mn ²⁺ , and BaMgAl ₁₀ O ₁₇ : Eu ²⁺ emitting blue light are known.

Among them, a blue phosphor, which is a BAM-based phosphor whose base material is BaMgAl ₁₀ O ₁₇ , requires that Eu, which is the emission center, be activated by divalent in order to increase the emission luminance. It is manufactured by firing (for example, see Non-Patent Document 1). The reason is that when this phosphor is fired in an oxidizing atmosphere, Eu becomes trivalent, and Eu cannot be substituted for a divalent Ba position in the host crystal, so that it cannot be an active luminescent center and the luminous brightness is reduced. is there. Further, the blue phosphor does not fulfill its original purpose, and emits red light unique to Eu ³⁺ .

In addition, europium-activated yttrium oxysulfide (Y ₂ O ₂ S: Eu ³⁺ ), which is a red phosphor, is produced by firing in an oxidizing atmosphere because Eu needs to be activated with trivalence. On the other hand, in a phosphor in which the host crystal is composed of an oxide, it is considered that oxygen atoms are deprived from the host crystal during firing and oxygen defects are generated in the phosphor. As a method of repairing such oxygen deficiency, there is disclosed a method of firing Y ₂ O ₂ S: Eu ³⁺ , which activates Eu trivalently, with an inert gas containing oxygen (Patent Document 1). reference).
Phosphors Society of Japan, “Phosphor Handbook”, Ohmsha, p. 170 JP-A-2000-290649 (pages 2-3)

  However, compared to an oxide phosphor produced by firing in an oxidizing atmosphere, an oxide phosphor produced by firing in a reducing atmosphere increases oxygen defects in the host crystal because the reducing atmosphere tends to deprive the host crystal of oxygen. . Furthermore, when an oxide phosphor that needs to be fired in a reducing atmosphere is fired in an oxidizing atmosphere, there is a problem that it is difficult to maintain the original valence of the activator.

  That is, when ion bombardment due to irradiation or discharge of high-energy ultraviolet rays (wavelength: 147 nm) generated by the plasma display device is applied to the phosphor having many oxygen defects in the host crystal, the phosphor is likely to deteriorate with time. This is presumably because in a site having an oxygen vacancy, the bonds between atoms are weak, and when high-energy ultraviolet rays or ion bombardment is applied thereto, the crystal structure is easily disturbed and amorphous. An amorphous portion means deterioration of a host crystal, and in a plasma display device, luminance degradation over time, color shift due to chromaticity change, screen burning, and the like occur.

When an oxide phosphor that needs to be fired in a reducing atmosphere for oxygen defect repair is fired in an oxidizing atmosphere, for example, in a BAM-based phosphor, Eu becomes trivalent Eu ³⁺ , causing significant deterioration in luminance.

  The present invention has been made in view of such a problem, and it is necessary to activate Eu and Mn, which are emission centers, in a divalent state. It is another object of the present invention to provide a method of manufacturing a phosphor capable of repairing oxygen vacancies, a phosphor having a high emission luminance and a small luminance degradation, and a plasma display device using the same.

  In the method for producing a phosphor of the present invention, a composite containing at least one of Eu and Mn as an activator as an emission center and containing at least one of Ba, Ca, Sr, and Mg elements is provided. A method for producing a phosphor using an oxide as a host crystal, comprising: a treating step in a reducing atmosphere in which a mixed material of the phosphor is fired at least once in a reducing atmosphere; and a treating step in an oxygen plasma atmosphere after the treating step in the reducing atmosphere. In an oxygen plasma atmosphere. By adopting such a manufacturing method, since the oxygen vacancies of the host crystal generated in the processing step in the reducing atmosphere are repaired by the processing in the oxygen plasma atmosphere, the production of the phosphor with high emission luminance and small luminance deterioration is performed. Method.

The manufacturing method of the phosphor of the present invention, the composition formula of the _{phosphor, Ba (1-xy) Sr} y MgAl 10 O 17: Eu x ( although, 0.01 ≦ x ≦ 0.20,0 ≦ y ≦ 0.30). In such an aluminate phosphor, the effect of repairing oxygen defects in the host crystal is large by using the above-described manufacturing method.

In the plasma display device of the present invention using the phosphor, a plurality of discharge cells of one color or a plurality of colors are arranged, and a phosphor layer of a color corresponding to the discharge cell is provided. there a plasma display device which emits light when excited by ultraviolet radiation, at least one phosphor layer of the phosphor layer, composition _{formula, Ba (1-xy) Sr} y MgAl 10 O 17: in Eu _x, and Includes phosphor treated in oxygen plasma atmosphere. With such a plasma display device, the emission luminance is high and the number of oxygen defects in the host crystal of the phosphor is small, so that the occurrence of luminance deterioration during actual use is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a fluorescent substance whose host crystal which needs to activate Eu and Mn which are luminescence centers in bivalence is an oxide, oxygen defect can be repaired, without lowering luminescence brightness. Thus, it is possible to provide a plasma display device having a high emission luminance and a small luminance degradation.

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

FIG. 1 is a process chart showing a method of manufacturing a phosphor according to an embodiment of the present invention. The synthesis of BaSrMgAl ₁₀ O ₁₇ : Eu which is one of aluminate phosphors will be described as an example.

  In the powder weighing step of Step 1, the following materials, which are generally carbonates, oxides and hydroxides, are used as raw materials for each metal, and weighed. That is, barium carbonate as a barium raw material, barium hydroxide, barium oxide, barium compounds such as barium nitrate, strontium raw materials strontium carbonate, strontium hydroxide, strontium compounds such as strontium nitrate, magnesium raw materials magnesium carbonate, magnesium hydroxide, Magnesium compounds such as magnesium oxide and magnesium nitrate, aluminum compounds such as aluminum oxide, aluminum hydroxide and aluminum nitrate as aluminum raw materials, and europium compounds such as europium oxide, europium carbonate, europium hydroxide and europium nitrate as europium raw materials are used. . Then, these raw materials are weighed so as to have a predetermined molar ratio of constituent ions. In addition, each raw material is not limited to carbonate, oxide, and hydroxide, and may be any compound.

  In the mixing step of step 2, a flux that is a crystal growth accelerator such as aluminum fluoride, barium fluoride, magnesium fluoride, or the like is simultaneously mixed with the weighed raw materials as necessary. Here, as a mixing means, for example, a ball mill is used for mixing for about 1 to 5 hours. The raw materials can be mixed by any method such as wet mixing with a ball mill, mixing by a ball mill, co-precipitation, or mixing in a liquid phase using a material obtained by converting each metal into an alkoxide as a raw material. .

  In the filling step of Step 3, the mixture is filled in a heat-resistant crucible such as a high-purity alumina crucible.

  In the air atmosphere treatment step of Step 4, the filled mixed powder is fired in an air atmosphere at a temperature range of 800 ° C. or more and 1500 ° C. or less for 1 hour to 10 hours in order to promote crystal growth of a host crystal. I do. Step 4 is not an essential step because it promotes crystal growth.

  In the processing step in a reducing atmosphere in step 5, the filled mixed powder is fired in a reducing atmosphere, for example, a nitrogen atmosphere at a temperature capable of forming a desired crystal structure. The aluminate phosphor according to the embodiment of the present invention is fired in a temperature range of 1100 ° C. or more and 1500 ° C. or less for 1 hour to 50 hours.

  In the processing step in the oxygen plasma atmosphere in step 6, the phosphor powder having a predetermined size is exposed to an oxygen plasma atmosphere at 400 to 450 ° C. for 1 to 2 hours. By the heat treatment in such an atmosphere, oxygen atoms enter the oxygen deficient portions of the host crystal generated in the processing step in the reducing atmosphere, and the oxygen vacancies are repaired.

  In the pulverizing / dispersing / washing / drying step of Step 7, the mixed powder treated in the oxygen plasma atmosphere is sufficiently cooled, and then pulverized and dispersed in a wet system for about 1 hour using a bead mill as a dispersing means, and washed with water. Here, the pulverization / dispersion of the mixed powder is not limited to a bead mill, and any other dispersing device such as a ball mill or a jet mill may be used. Thereafter, the phosphor powder that has been pulverized, dispersed and washed with water is dehydrated and sufficiently dried, and then sieved to obtain a phosphor powder.

  In this embodiment, the treatment step in the reducing atmosphere and the subsequent treatment step in the oxygen plasma atmosphere are performed once. However, the treatment step in the reducing atmosphere for increasing the luminance by making Eu divalent and the oxygen treatment of the base crystal are performed. The process in an oxygen plasma atmosphere for repairing the defect may be repeated a plurality of times. Further, the treatment step in the air atmosphere for promoting the crystal growth of the host crystal may be performed one or more times before the treatment step in the reducing atmosphere. Then, after each processing step, the powder may be pulverized, dispersed, and washed with water.

  FIG. 2 is a cross-sectional view of a processing apparatus in a processing step in an oxygen plasma atmosphere according to the embodiment of the present invention. The temperature of the vacuum chamber 41 can be controlled by a heater 42. Oxygen gas 43A is supplied from the gas inlet 43, and is turned into plasma by a 13.56 kHz RF plasma device 44 as a plasma excitation source, and becomes extremely active oxygen gas. Then, the charging valve 45 is opened to supply the phosphor 40 having oxygen deficiency, and the phosphor 40 having the oxygen deficiency is repaired when exposed to the active oxygen gas 43A when the phosphor 40 is dropped continuously little by little. It becomes the phosphor 49 and falls.

  In order to complete the repair of oxygen deficiency, the transfer pipe valve 46 is opened, the phosphor 40 having oxygen deficiency is transferred upward by the transfer pipe 48 and dropped into the vacuum chamber 41 again, and completely. Repeat until oxygen deficiency is repaired. After performing a predetermined oxygen deficiency repair, the phosphor 40 having an oxygen deficiency is released, the vacuum is released, and the discharge valve 47 is opened to be taken out.

Next, various aluminate phosphor _{Ba (1-xy) Sr y} MgAl 10 O 17: After the Eu _x least reducing atmosphere during processing, carried out characteristics when fabricated respectively in the processing step an oxygen plasma atmosphere This will be described based on an example.

(Example 1)
As raw materials, powders of barium carbonate (BaCO ₃ ), magnesium carbonate (MgCO ₃ ), europium oxide (Eu ₂ O ₃ ), and aluminum oxide (Al ₂ O ₃ ), which were sufficiently dried to a constant weight, were prepared. These raw materials were weighed so that the molar ratio of constituent ions was Ba: Mg: Eu: Al = 0.99: 1.00: 0.01: 10.00. Next, aluminum fluoride as a crystal growth promoter was mixed with the above weighed raw materials for 3 hours using a ball mill.

  Next, the mixture was filled in a high-purity alumina crucible and fired at 1200 ° C. for 1 hour in an air atmosphere. Thereafter, the fired mixed powder was fired a second time at 1200 ° C. for 10 hours in a reducing atmosphere of 20% of nitrogen gas and 80% of hydrogen gas. Thereafter, the calcined powder is pulverized, dispersed, washed, dried, sieved, and then exposed to oxygen plasma several times at a temperature of 400 ° C. in a vacuum chamber by the treatment apparatus in an oxygen plasma atmosphere shown in FIG. Time) treatment.

And the powder which performed such a process was washed with water. The water-washed mixed powder phosphor was dehydrated, dried sufficiently, and then sieved to prepare a phosphor powder having a general formula of Ba _0.99 MgAl ₁₀ O ₁₇ : Eu _0.01 .

  Next, the prepared phosphor powder was irradiated with vacuum ultraviolet light having a peak wavelength of 146 nm obtained by a vacuum ultraviolet excimer light irradiation device (Ushio Inc .: 146 nm light irradiation device), and a luminance meter (Minolta Camera Co., Ltd.) ): The luminance with respect to the irradiation time was measured by LS-110). Here, a relative luminance value defined below was used as an evaluation index as a characteristic value of luminance. The relative luminance value is obtained by multiplying the relative initial light emission intensity of each phosphor by a luminance maintenance ratio. Here, the relative initial luminous intensity indicates a ratio of the initial luminous intensity of each of the materials of the examples when the initial luminous intensity of the conventional product is set to 100. Further, the luminance maintenance ratio is a percentage value obtained by dividing the luminance of each example material at 5000 hours by the initial light emission intensity of each example material. That is, the relative luminance value is a comparison of the luminance of the phosphor after a certain period of time between the conventional phosphor and the phosphor of the embodiment of the present invention. Table 1 shows material composition ratios, processing conditions, and relative luminance values.

(Examples 2 and 3)
Example 2, Ba: Mg: Eu with the same raw material as in Example 1 except that the molar ratio of constituent ions was set to Ba: Mg: Eu: Al = 0.9: 1.0: 0.1: 10.0. : Al = 0.8: 1.0: 0.2: 10.0 is the third embodiment. The differences between the second and third embodiments and the first embodiment are as follows. In Example 2, baking was performed at 1400 ° C. for 1 hour in an atmosphere of air at 1400 ° C. for 1 hour in a reducing atmosphere of 95% nitrogen and 5% hydrogen at a partial pressure ratio. In Example 3, baking was performed at 800 ° C. for 1 hour in an air atmosphere and at 1200 ° C. for 10 hours in a reducing atmosphere containing 100% of nitrogen at a partial pressure ratio. Then, the phosphor powders produced under these conditions were evaluated in the same manner as in Example 1 by relative luminance values. Table 1 shows processing conditions and the like and relative luminance values.

(Examples 4 to 9)
In addition to the raw material of Example 1, powder of strontium carbonate (SrCO ₃ ) was prepared, and the molar ratio of constituent ions was Ba: Sr: Mg: Eu: Al = 0.89: 0.10: 0. Example 4: the case where the ratio was set to 01: 10.00, and Example 5 where the ratio of Ba: Sr: Mg: Eu: Al was 0.8: 0.1: 1.0: 0.1: 10.0. In Example 6, Ba: Sr: Mg: Eu: Al = 0.7: 0.1: 1.0: 0.2: 10.0 was used, and Ba: Sr: Mg: Eu: Al = 0.69. : 0.30: 1.00: 0.01: 10.00 in Example 7, Ba: Sr: Mg: Eu: Al = 0.6: 0.3: 1.0: 0.1: Example 8 was set to 10.0, and Example 9 was set to Ba: Sr: Mg: Eu: Al = 0.5: 0.3: 1.0: 0.2: 10.0. The differences between Examples 4 to 9 and Example 1 are as follows. In Example 4, firing was performed at 1100 ° C. for 10 hours in a reducing atmosphere of 100% hydrogen at a partial pressure ratio without firing in an air atmosphere. In Example 5, baking was performed at 1300 ° C. for 1 hour in an air atmosphere and at 1200 ° C. for 10 hours in a reducing atmosphere of 99% nitrogen and 1% hydrogen at a partial pressure ratio. In Example 6, firing was performed at 1400 ° C. for 1 hour in an atmosphere of air at 1400 ° C. for 1 hour in a reducing atmosphere of 90% nitrogen and 10% hydrogen at a partial pressure ratio. In Example 7, baking was performed at 1300 ° C. for 1 hour in an air atmosphere at 1300 ° C. in a reducing atmosphere of 98% nitrogen and 2% hydrogen at a partial pressure ratio for 1 hour. In Example 8, firing was performed at 1000 ° C. for 1 hour in an air atmosphere, and at 1300 ° C. for 10 hours in a reducing atmosphere of 90% nitrogen and 10% hydrogen at a partial pressure ratio. In Example 9, firing was performed at 1200 ° C. for 1 hour in an air atmosphere at 1300 ° C. for 10 hours in a reducing atmosphere of 50% nitrogen and 50% hydrogen at a partial pressure ratio. Then, the phosphor powders produced under these conditions were evaluated in the same manner as in Example 1 by relative luminance values. Table 1 shows processing conditions and the like and relative luminance values.

(Comparative example)
In Comparative Example, a phosphor having the same molar ratio of constituent ions as in Example 5 was produced by a conventional manufacturing method (conventional product). The difference from Example 5 was due to an oxygen plasma atmosphere for repairing oxygen defects. There is no processing step. The luminance retention ratio of this sample is 69%, and therefore, the relative luminance value is 69.

As can be seen from Table 1, aluminate phosphors _{Ba (1-xy) Sr y} MgAl 10 O 17: in the range of Eu in _{x 0.01 ≦ x ≦ 0.20,0 ≦ y} ≦ 0.30, the relative It can be seen that the luminance value is improved by an average of 16 and the light emission luminance is higher than that of the comparative example which is a conventional product. Note that the aluminate phosphor _{Ba (1-xy) Sr y} MgAl 10 O 17: Ba in Eu _x, Sr, the amount of Eu x, y is remarkable effect in the above-mentioned range can be obtained, Mg As for the amount of Al and Al, the luminous efficiency improving effect did not change if the composition range was about ± 5% of the above molar amount (1 for Mg and 10 for Al).

  In Examples 1 to 9, the firing conditions in the reducing atmosphere related to the preparation of the sample and the firing conditions in the air atmosphere prior to it were variously changed. It is considered that a difference to the relative luminance value was caused. In particular, the molar ratios of the constituent ions are the same, and only the presence or absence of a treatment step in an oxygen plasma atmosphere for repairing oxygen defects is different. This is because a difference of 20 in the relative luminance value is observed between the example 5 and the comparative example. Further, the effect of the treatment in the oxygen plasma atmosphere is inferred from the following.

First, Eu is often used as an activator, which can usually be divalent or trivalent. In the case of a BAM-based blue phosphor, for example, Ba _(1-x) MgAl ₁₀ O ₁₇ It is necessary to replace the divalent Eu with the divalent Ba while producing the parent crystal of the above to form a stable luminescence center Eu ²⁺ . For this purpose, as a conventional basic firing method, firing may be performed at a high temperature of 1000 to 1500 ° C. for 4 hours or more in an appropriate reducing atmosphere.

  Secondly, regarding the repair of oxygen defects in the host crystal generated in the above-described reducing atmosphere, the effect of repairing oxygen defects was confirmed when the phosphor was continuously treated in an oxygen plasma atmosphere at 400 to 450 ° C.

Further, Sr is may not be included in the composition of the phosphor, a portion of the Ba ²⁺ Sr contains is replaced with a more ionic radius of small Sr ^2+, the lattice constants of the crystal structure By slightly shrinking, the emission color of the blue phosphor can be made closer to a more desirable color.

  Next, FIG. 3 is a perspective view of a main part of the plasma display device according to the embodiment of the present invention. The front plate PA1 has a display electrode 15 composed of a scanning electrode 12a and a sustain electrode 12b, and a dielectric layer 13 formed over the transparent and insulating front substrate 11 so as to cover them. The protective layer 14 is formed thereon.

Here, the display electrodes 15 have a constant pitch on the front substrate 11 and are formed in a predetermined number. In addition, the dielectric layer 13 is required to cover the display electrode 15 after the display electrode 15 is formed, and in general, a low-melting glass is formed by a printing and firing method. . As a glass paste material, for example, a so-called (PbO-SiO ₂ ) containing lead oxide (PbO), silicon oxide (SiO ₂ ), boron oxide (B ₂ O ₃ ), zinc oxide (ZnO), barium oxide (BaO) and the like is used. -B ₂ O ₃ -ZnO-BaO) based glass composition can be used low-melting glass paste having. By repeating, for example, screen printing and baking using this glass paste, the dielectric layer 13 having a predetermined thickness can be easily obtained. Note that this film thickness may be set according to the thickness of the display electrode 15, a target capacitance value, or the like. In the embodiment of the present invention, the thickness of the dielectric layer 13 is about 40 μm. Further lead oxide (PbO), it is also possible to use a glass paste mainly composed of at least one of bismuth oxide (Bi ₂ O _3), and phosphorus oxide (PO _4).

  The protective layer 14 is provided to prevent the dielectric layer 13 from being sputtered by plasma discharge, and is required to be a material having excellent sputtering resistance. For this reason, magnesium oxide (MgO) is often used.

  On the other hand, data electrodes 17 for writing image data are formed in a direction orthogonal to the display electrodes 15 of the front panel PA1 on a transparent and insulating rear substrate 16. After an insulator layer 18 is formed on the surface of the rear substrate 16 so as to cover the data electrodes 17, a partition wall 19 is formed parallel to the data electrodes 17 and substantially at the center between the data electrodes 17. Further, the phosphor layer 20 is formed in a region sandwiched between the partition walls 19 to form the back plate PA2. In this phosphor layer 20, phosphors emitting R, G, and B light are formed adjacent to each other, and these constitute a pixel.

The data electrode 17 may be a single layer structure film of silver, aluminum, copper, or the like having a low resistance, or a multilayer structure film such as a two-layer structure of chromium and copper, or a three-layer structure of chromium, copper, and chromium. It is formed by a thin film forming technique such as sputtering or sputtering. Further, the insulator layer 18 can be formed using the same material and the same film forming method as the dielectric layer 13. Further, a glass paste containing at least one of lead oxide (PbO), bismuth oxide (Bi ₂ O ₃ ), and phosphorus oxide (PO ₄ ) may be used. A phosphor, which is manufactured by the above-described manufacturing method and emits R light, G light, and B light, respectively, is applied to a region surrounded by the partition wall 19 by, for example, an ink-jet method to form a phosphor layer 20.

  When the front panel PA1 and the rear panel PA2 face each other, a discharge space 30 surrounded by the partition wall 19, the protective layer 14 on the front substrate 11, and the phosphor layer 20 on the rear substrate 16 is formed. The discharge space 30 was filled with a mixed gas of Ne and Xe at a pressure of about 66.5 kPa, and was excited when an AC voltage of several tens to several hundreds of kHz was applied between the scan electrode 12a and the sustain electrode 12b to cause discharge. The phosphor layer 20 can be excited by ultraviolet rays generated when the Xe atoms return to the ground state. The phosphor layer 20 emits R light, G light, or B light according to the applied material by this excitation. Therefore, if a pixel and a color to be emitted by the data electrode 17 are selected, a predetermined pixel portion can be obtained. The required color can be emitted, and a color image can be displayed.

  FIG. 4 is a graph showing a luminance change rate of the phosphor used in the above-described plasma display device. A pulse voltage having an amplitude of 180 V and a frequency of 15 kHz was applied between the display electrodes 15, and the phosphor of Example 5 manufactured in the embodiment of the present invention and the phosphor of the comparative example manufactured by the conventional method were examined. This is a change over time in luminance. The light emission luminance in the initial lighting period is set to 100%, and a value obtained by dividing the light emission luminance in each lighting time by the light emission luminance in the initial lighting period is defined as a luminance change rate. The luminance change rate at the time of lighting for 5000 hours is reduced to 72% for the phosphor manufactured by the conventional method, while the phosphor manufactured according to the embodiment of the present invention maintains the emission luminance of 85%. As a result, a 13% improvement was obtained from only the luminance change rate, and luminance deterioration was suppressed. This is because the phosphor obtained by the manufacturing method according to the embodiment of the present invention is fired in a reducing atmosphere and then treated in an oxygen plasma atmosphere.Therefore, the crystal structure of the phosphor has few oxygen defects, The portion having an amorphous structure is also reduced. As a result, even if there is ultraviolet irradiation or ion bombardment, deterioration of the crystal structure is small and luminance deterioration is also small.

In this embodiment, the case where Eu ²⁺ is used as an activator in the BAM system has been described. However, CaMgSi ₂ O ₆ : Eu using Eu ²⁺ as an activator, or Mn as an activator ^Even with the green phosphor (Ba, Sr, Mg) O.aAl ₂ O ₃ : Mn having an oxide using ²⁺ as a host crystal, the light emission luminance is high due to the treatment in the oxygen plasma atmosphere, and the effect of suppressing the luminance deterioration is obtained. Was.

  As described above, according to the present invention, oxygen vacancies can be reduced without lowering the emission luminance even in a phosphor whose host crystal, which needs to activate Eu, Mn, which is a luminescent center, is divalent. The present invention can be repaired and is useful for improving the performance of an image display device represented by a plasma display device, or a lighting device represented by a rare gas discharge lamp or a high-load fluorescent lamp.

Process diagram showing a method for manufacturing a phosphor according to an embodiment of the present invention Sectional view of a processing apparatus in a processing step in an oxygen plasma atmosphere according to an embodiment of the present invention. Main part perspective view of a plasma display device according to an embodiment of the present invention 4 is a graph showing a luminance change rate of a phosphor used in the plasma display device according to the embodiment of the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 11 Front substrate 12a Scan electrode 12b Sustain electrode 13 Dielectric layer 14 Protective layer 15 Display electrode 16 Back substrate 17 Data electrode 18 Insulator layer 19 Partition wall 20 Phosphor layer 30 Discharge space 40 Phosphor with oxygen defect 41 Vacuum chamber 42 Heating Heater 43 Gas inlet 43A Oxygen gas 44 RF plasma device 45 Input valve 46 Transfer tube valve 47 Discharge valve 48 Transfer tube 49 Phosphor with oxygen deficiency repaired PA1 Front plate PA2 Back plate

Claims (4)

A plasma display device in which a plurality of discharge cells of one color or a plurality of colors are arranged, and a phosphor layer of a color corresponding to the discharge cell is provided, and the phosphor layer emits light when excited by ultraviolet rays.
The phosphor layer at least one phosphor layer of the composition _{formula, Ba (1-xy) Sr} y MgAl 10 O 17: plasma display configured in Eu _x, and the treated phosphor in an oxygen plasma atmosphere apparatus. The composition formula _{Ba (1-xy) Sr y} MgAl 10 O 17: In Eu _x, a plasma display device according to claim 1, wherein 0.01 ≦ x ≦ 0.20,0 ≦ y ≦ 0.30. Fluorescence in which at least one or more of Eu and Mn is added as an activator to serve as a light emission center and a composite oxide containing at least one of Ba, Ca, Sr, and Mg elements as a host crystal. A method of manufacturing a body,
A treatment step in a reducing atmosphere in which the mixed material of the phosphor is fired at least once or more in a reducing atmosphere;
A process in an oxygen plasma atmosphere, wherein the process is performed in an oxygen plasma atmosphere after the processing step in a reducing atmosphere. The composition formula of the _{phosphor, Ba (1-xy) Sr} y MgAl 10 O 17: Eu x ( although, 0.01 ≦ x ≦ 0.20,0 ≦ y ≦ 0.30) in an of claims 3 A method for producing the phosphor according to the above.

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