JP2005322563A - Plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display panel in which deterioration of the property of a phosphor layer is prevented by removing impurity gas in the plasma display panel and charge tendency of the phosphor is matched to have high reliability. <P>SOLUTION: The plasma display panel has a red phosphor layer, a green phosphor layer, and a blue phosphor layer formed at least at a part of an inner wall of a discharge space that is constructed by placing a front panel substrate and a rear panel substrate opposed to each other. The green phosphor layer contains a green phosphor 36 of which surface is covered by a positive charged oxide 36a and the surface of the positive charged oxide 36a is covered in an island shape by oxide 36b that stores and decomposes hydrocarbon gas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma display panel, and more particularly to a plasma display panel in which discharge characteristics and phosphor characteristics are stabilized.

  2. Description of the Related Art In recent years, color display devices using plasma display panels (hereinafter referred to as PDPs) in color display devices used in image display devices such as computers and televisions can achieve large, thin, and lightweight colors. It is attracting attention as a display device.

  The PDP is configured by sealing a front panel substrate and a rear panel substrate with a predetermined discharge space. On the front panel substrate and the back panel substrate, electrodes, dielectric layers, partition walls, phosphor layers, and the like are formed by firing a structure containing an organic binder. In the PDP manufacturing process, especially in the sealing process for sealing the front panel substrate and the back panel substrate, the impurity gas in which the organic binder contained in the frit glass used for the sealing material is thermally decomposed diffuses into the PDP. To do. The impurity gas components are mainly water vapor, carbon dioxide gas, and hydrocarbon gas, but these impurity gases are adsorbed on the phosphor layer in the PDP, which may cause problems such as deterioration of discharge characteristics and reduction of luminance. Known (for example, Patent Document 1, Non-Patent Document 1, etc.). Therefore, reducing the impurity gas inside the PDP and improving reliability such as stabilization of discharge characteristics and suppression of changes with time are one of important issues.

  In order to remove these impurity gases, attempts have been made to install getters and adsorbents in the PDP, exhaust pipes, etc., and to adsorb and remove the impurity gases (for example, Patent Document 2 and Patent Document 3).

A red phosphor layer, a green phosphor layer, and a blue phosphor layer are formed between the partition walls of the back panel substrate. The phosphor of the red phosphor layer is (Y, Gd) BO ₃ : Eu or Y ₂ O ₃ : Eu, the green phosphor is Zn ₂ SiO ₄ : Mn, the blue phosphor is BaMgAl ₁₀ O ₁₇ : Eu, etc. Is used. Among these phosphors, only the green phosphor has a negative charge tendency, which causes problems such as unstable discharge characteristics. Therefore, examples in which the surface of the green phosphor is coated with fluoride or oxide to make the charging tendency positive are disclosed (for example, Patent Document 4 and Patent Document 5).
JP 2000-311588 A JP 2003-281994 A JP 11-329246 A Japanese Patent Laid-Open No. 11-86735 JP 2001-236893 A FPD Technology Taizen Co., Ltd. Electronic Journal October 25, 2000 PP615-618

  However, in the method in which a getter is provided in a specific region inside the PDP and the impurity gas is adsorbed, the discharge space is partitioned by the barrier ribs, so the getter effect cannot be applied to the entire region of the PDP, and the impurity gas remains An area is generated, causing uneven display. Furthermore, there is a problem that the getter is heated during discharge and the impurity gas is released again into the PDP. Further, in the method of removing the impurity gas by providing a getter inside the exhaust pipe, there is a problem that the impurity gas component is gradually accumulated in the getter and the ability to remove the impurity gas is gradually lowered.

  On the other hand, in order to make the charging tendency of the negatively charged green phosphor coincide with each other, it is necessary to coat the surface of the green phosphor with oxide or fluoride separately from the installation of the getter, which increases the number of manufacturing processes. In addition, the structure of the PDP is complicated, and the manufacturing cost is high and there is a problem in reliability.

  The present invention solves the above problems, and removes the impurity gas in the PDP with a simple structure and matches the charging tendency of the phosphor, thereby providing a highly reliable PDP.

  In order to solve the above-described problems, the PDP of the present invention includes a red phosphor layer, a green phosphor layer, and at least a part of an inner wall of a discharge space formed by facing a front panel substrate and a back panel substrate. In the PDP formed with the blue phosphor layer, the green phosphor layer is coated with a first oxide having a positive charge property on the surface of the green phosphor, and the surface of the first oxide is coated with a hydrocarbon gas. It contains a green phosphor coated with a second oxide that occludes and decomposes.

  According to such a configuration, the charging tendency of all the phosphors can be matched with a simple structure, and the impurity gas in the PDP can be efficiently decomposed into water and carbon dioxide gas having little influence on the characteristics. It can be removed, and a low-cost and highly reliable PDP can be realized.

Furthermore, it is desirable that the first oxide having positive chargeability is one or more of Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , and MgO. The charging tendency of the body can be matched more.

Furthermore, the second oxide that occludes and decomposes the hydrocarbon gas is desirably one or more of NiO, MnO, CrO ₂ , ZrO ₂ , Fe ₂ O ₃ , BaTiO ₃ , and TiO ₂ , According to this structure, hydrocarbon gas can be more effectively occluded and removed into water and carbon dioxide gas.

  Further, it is desirable that a platinum group element is added to the second oxide that occludes and decomposes the hydrocarbon gas. According to this configuration, the hydrocarbon gas is more effectively occluded and decomposed into water and carbon dioxide gas. Can be removed.

  As described above, according to the present invention, it is possible to realize a highly reliable PDP by removing the hydrocarbon-based impurity gas in the PDP and matching the charging tendency of all the phosphors.

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

FIG. 1 is a cross-sectional view showing the structure of a PDP in an embodiment of the present invention. The PDP main body 10 includes a front panel substrate 20 and a back panel substrate 30. The front panel substrate 20 includes a front glass substrate 21, a plurality of parallel display electrodes 22 formed on the inner surface of the front panel substrate 21, a dielectric layer 23 covering the display electrodes 22, and the like. The back panel substrate 30 is formed on a back glass substrate 31, a plurality of address electrodes 32 formed on the inner surface thereof and parallel to each other and orthogonal to the display electrodes 22, and a dielectric layer 33 covering the address electrodes 32. The barrier ribs 34 and the phosphor layers 35 that emit light in red, green, and blue, respectively, are formed between the barrier ribs 34. The front panel substrate 20 and the back panel substrate 30 are arranged to face each other with a discharge space 40, and the periphery is sealed by a sealing material 41 made of frit glass or the like. Further, the back glass substrate 31 is sealed by exhausting the gas in the discharge space 40 and sealing and sealing neon, xenon, or the like serving as a discharge gas at a pressure of 53 kPa to 80 kPa. Further, the phosphor layer 35 includes a red phosphor layer 35 a, a green phosphor layer 35 b, and a blue phosphor layer 35 c formed between the partition walls 34. In this embodiment, (Y, Gd) BO ₃ : Eu or Y ₂ O ₃ : Eu is used as a red phosphor, Zn ₂ SiO ₄ : Mn is used as a green phosphor, and BaMgAl is used as a blue phosphor. ₁₀ O ₁₇ : Eu is used.

  In the PDP having such a configuration, a gas discharge is generated by applying a voltage to each electrode, and each color of the red phosphor layer 35a, the green phosphor layer 35b, and the blue phosphor layer 35c is generated by ultraviolet rays generated by the discharge. The phosphor is excited to emit light to perform color display.

  FIG. 2 is a detailed cross-sectional view schematically showing the structure of the phosphor layer 35. As shown in FIG. 2, the phosphor layer 35 is a film having a structure in which several to several tens of particulate phosphors 36 are laminated.

FIG. 3 is an enlarged cross-sectional view of green phosphor particles made of Zn ₂ SiO ₄ : Mn among the phosphors 36 constituting the main part of the embodiment of the present invention. On the first layer on the surface of the phosphor 36, a positively chargeable oxide 36 a which is a first oxide such as Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , MgO is coated almost uniformly. Yes. The second layer thereon _{NiO, MnO,} CrO _2, a _{ZrO 2, Fe 2 O 3,} BaTiO 3, TiO 2 second oxide is occluded decompose oxides 36b hydrocarbon gas such places The film is formed in an island shape with a gap. Further, a platinum group element 36c such as Pt, Pd, Rh, Ir, Os, Ru is dispersedly added to the oxide 36b that occludes and decomposes hydrocarbon gas.

As described above, (Y, Gd) BO ₃ : Eu is used for red, BaMgAl ₁₀ O ₁₇ : Eu is used for blue, and Zn ₂ SiO ₄ : Mn is used for green as phosphors used in PDP. It is done. Of these, (Y, Gd) BO ₃ : Eu, which is a red phosphor, and BaMgAl ₁₀ O ₁₇ : Eu, which is a blue phosphor, have positive charging characteristics, but Zn ₂ SiO _4, which is a green phosphor. : Mn has a negative charging property. For this reason, the charging tendency of the phosphor is different as it is, and the discharge characteristics are not stable. As in the embodiment of the present invention, by coating the surface of the green phosphor 36 with the positively chargeable oxide 36a, all the green phosphors 36 have positive chargeability, and the charging tendency of each color phosphor is increased. The discharge characteristics of the PDP can be stabilized.

  On the other hand, when forming the display electrode 22, the dielectric layers 23 and 33, the partition wall 34, the phosphor layer 35, etc. of the PDP main body 10 shown in FIG. 1, the respective base materials and organic binders are usually kneaded. Is applied to form a predetermined shape, followed by firing. Further, a sealing process for sealing the front panel substrate 20 and the back panel substrate 30 is performed. In particular, in the sealing step, an impurity gas generated by pyrolyzing an organic binder or the like contained in the frit glass used for the sealing material 41, or an impurity gas generated by pyrolyzing the unfired organic binder of each of the above-described components. Diffuses into the PDP. The impurity gas components are mainly water vapor, carbon dioxide gas, hydrocarbon gas, etc., but these impurity gases are adsorbed by the phosphors in the phosphor layer 35 in the PDP, resulting in deterioration of discharge characteristics and luminance. It is known to cause problems such as degradation.

  In order to remove the influence of these impurity gases, it is common to perform a process of once exhausting the gas in the PDP and then enclosing the discharge gas. However, even if this step is performed, a slight amount of impurity gas remains in the PDP. Among the impurity gases, the hydrocarbon gas is a green phosphor layer 35b or a blue phosphor even at a low concentration of about 1/100 to 1/1000 of water and about 1/10 to 1/100 of carbon dioxide. It has been found that it causes the characteristic deterioration of the layer 35c. The mechanism is that hydrocarbon gas is decomposed into hydrogen and carbon by the energy of discharge, and the phosphor layer 35 is reduced by these hydrogens to generate oxygen defects, or carbon adheres to the phosphor layer 35 and is colored. Therefore, it is considered that the luminance decreases.

In addition, according to the present invention, the impurity gas is absorbed by the action of the oxide 36b that occludes and decomposes the hydrocarbon gas provided in an island shape in the second layer of the phosphor 36. C _x H _y based gas is a gas or a hydrocarbon causes oxidative decomposition and C _{x H} y _O based gas partially oxidized into water and carbon dioxide. Here, when the hydrocarbon gas is oxidatively decomposed, water and carbon dioxide gas are generated. However, the hydrocarbon gas is originally small compared to the water and carbon dioxide gas remaining in the PDP after sealing, and these are decomposed by the decomposition. Even if it is increased, it has been found that the influence on the deterioration of the phosphor is small. This eliminates the need for a getter that is conventionally installed in the PDP.

  Further, since the green phosphor layer 35b is formed over the entire area of the image display area, the oxide 36b formed in the green phosphor 36 has an effect of adsorbing and removing impurity gas such as hydrocarbon gas over the entire area. . For this reason, it is possible to remove the impurity gas more uniformly than when a getter material is placed in or outside the image display area as in the prior art, resulting in non-uniform discharge characteristics deterioration and luminance reduction. Etc. can be reduced.

  Further, as shown in FIG. 3, the oxide 36b that occludes and decomposes the hydrocarbon gas is coated in an island shape having gaps in some places. As the effect of 36a increases, the surface area of the oxide 36b increases and the effect of decomposing hydrocarbon gas becomes higher. Further, by adding the platinum group element 36c to the oxide 36b, the oxidation catalyst effect can be promoted, and the hydrocarbon gas can be decomposed and removed more effectively.

  With the configuration described above, the charging tendency of the green phosphor is made to coincide with the charging tendency of the red phosphor and the blue phosphor, so that the discharge characteristics are stabilized. It can be decomposed and removed into water and carbon dioxide, which have little effect on properties. Therefore, a highly reliable PDP can be realized at low cost.

In the following method, Al ₂ O ₃ which is a positively charged oxide is coated on the first layer of the green phosphor made of Zn ₂ SiO ₄ : Mn, and hydrocarbon gas is occluded in the second layer. NiO, which is an oxide that decomposes, was coated in an island shape.

First, Zn ₂ SiO ₄ : Mn powder was put into an aqueous solution of aluminum nitrate, stirred and dried, and then fired at 400 ° C. to 600 ° C. to make the surface of Zn ₂ SiO ₄ : Mn positively charged. An Al ₂ O ₃ film that is an oxide is formed. Next, this powder is put into a nitrate solution of NiO, stirred and dried, and then calcined at 400 ° C. to 600 ° C., and is an oxide that occludes and decomposes hydrocarbon gas on the Al ₂ O ₃ film. A film of NiO is formed. At this time, since NiO is a negatively charged oxide, a film is formed in an island shape having gaps in some places. Next, this powder is put into an aqueous solution of chloroplatinic acid, thoroughly stirred and dried, and then fired at 400 ° C. to 600 ° C., whereby platinum group element Pt is added to the surface of NiO.

In the above embodiment, Al ₂ O ₃ was used as the positively charged oxide. However, for Y ₂ O ₃ , La ₂ O ₃ , and MgO, Zn chloride is added to an aqueous solution of chloride, nitrate, or the like. ₂ SiO ₄ : Mn powder is added, and after stirring and drying, a film of each oxide can be formed on the surface of Zn ₂ SiO ₄ : Mn by firing at 400 ° C. to 600 ° C. . In yet above embodiments, the hydrocarbon gas as occlusion decompose oxides, the example of using _{NiO, MnO, CrO 2, ZrO} 2, Fe 2 O 3, BaTiO 3, the TiO ₂ is also their A Zn ₂ SiO ₄ : Mn powder having a positively charged oxide film in an aqueous solution of chloride, nitrate or the like is added, and after stirring and drying, each is fired at 400 ° C. to 600 ° C. An oxide film can be formed. In addition to the above-mentioned Pt, platinum group elements other than Pt, Rd, Ru, Ir, Os chlorides, nitrates, and organic compounds are added to an aqueous solution and stirred and dried. By baking, platinum group elements Pd, Rh, Ru, Ir, and Os can be added.

  The phosphor thus obtained was formed into an island-like film with a positively charged oxide in the first layer and an oxide that occludes and decomposes hydrocarbon gas in the second layer. Table 1 shows the results of examining the hydrocarbon adsorption amount ratio and the luminance change rate of the phosphor. The amount of adsorption of hydrocarbons was taken out for 5000 hours, and red, green, and blue phosphors were taken out, and the amount of adsorption of hydrocarbons was compared by gas analysis, and the luminance change rate of the green phosphor was examined.

  In Samples 1 to 11, Pt is added as a platinum group element to the oxide of the second layer, but when no platinum group element is added to the second layer, the hydrocarbon adsorption amount ratio Has increased to about 0.1 to 0.2. Further, Comparative Example 1 shows a case where there is no second layer, and Comparative Example 2 shows a case where there is neither a first layer nor a second layer.

  As shown in Table 1, compared with Comparative Example 1 and Comparative Example 2, in the example of the phosphor according to the present invention, the amount of adsorption of hydrocarbons in the phosphor is about 1/10 or less, and the green color after 5000 hours The luminance change rate of the phosphor is also about 1/5 or less, and it was confirmed that the stability of the characteristics is improved by the present invention.

  Furthermore, when a platinum group element is contained in the oxide of the second layer, the amount of adsorption of hydrocarbons can be reduced.

In the above description, the green phosphor layer is described by an example in which the green phosphor layer of Zn ₂ SiO ₄ : Mn is formed alone, but the general formula ReBO ₃ : Tb (Re is a rare earth element: Sc, Y, La, The present invention can also be applied to a case where it is used by mixing with a terbium-activated rare earth borate green phosphor represented by one or a plurality of solid solutions selected from Ce and Gd.

  According to the PDP of the present invention, since the luminance characteristic and discharge characteristic of the phosphor can be stabilized and a highly reliable PDP can be realized, it is useful for a large screen display device and the like.

Sectional drawing which shows the structure of PDP in embodiment of this invention Detailed cross-sectional view schematically showing the structure of the phosphor layer of the PDP Cross-sectional view showing enlarged green phosphor particles of the same PDP

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 PDP main body 20 Front panel substrate 21 Front glass substrate 22 Display electrode 23,33 Dielectric layer 30 Rear panel substrate 31 Rear glass substrate 32 Address electrode 34 Partition 35 Phosphor layer 35a Red phosphor layer 35b Green phosphor layer 35c Blue phosphor Body layer 36 (green) phosphor 36a plus chargeable oxide 36b oxide (which occludes and decomposes hydrocarbon gas) 36c platinum group element 40 discharge space 41 sealing material

Claims (4)

A plasma display panel in which a red phosphor layer, a green phosphor layer, and a blue phosphor layer are formed on at least a part of an inner wall of a discharge space formed by facing a front panel substrate and a back panel substrate, wherein the green phosphor The body layer is coated with a first oxide having a positive chargeability on the surface of the green phosphor, and the surface of the first oxide is coated with a second oxide that occludes and decomposes hydrocarbon gas. A plasma display panel comprising a phosphor. _2. The plasma according to claim 1, wherein the first oxide having positive chargeability is one or more of Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , and MgO. Display panel. The second oxide that occludes and decomposes hydrocarbon gas is one or more of NiO, MnO, CrO ₂ , ZrO ₂ , Fe ₂ O ₃ , BaTiO ₃ , and TiO _2. The plasma display panel according to claim 1 or 2. 4. The plasma display panel according to claim 1, wherein a platinum group element is added to the second oxide that occludes and decomposes hydrocarbon gas.

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