JP2011238499A - Plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PDP achieving a reduced persistence time of a green phosphor and suppressing luminous deterioration, an increase in an address voltage or the like due to a positive charge.SOLUTION: A phosphor layer 23 of the plasma display panel includes a green phosphor layer 23b comprising a mixture of a ZnSiO:Mn phosphor and a (Y,Gd)AlO:Ce (where, 0≤X≤1) phosphor. A ratio of Mn element relative to a sum of Zn element and Mn element (Mn/(Zn+Mn)) is 0.08-0.10 within 10 nm from the particle surface of the ZnSiO:Mn phosphor, and a ratio of a sum of Zn element and Mn element relative to Si element ((Zn+Mn)/Si) is 1.97-2.02. Furthermore, a mixture ratio of a (Y,Gd)BO:Tb phosphor in the mixture is 50-70 wt.%.

Description

  The present invention relates to a plasma display panel having a phosphor layer containing a phosphor excited by vacuum ultraviolet rays.

  In recent years, plasma display panels (hereinafter referred to as PDPs) are attracting attention as color display devices that can be large, thin, and lightweight as color display devices used for image display in computers and televisions.

The PDP performs full color display by additively mixing the so-called three primary colors of red, green, and blue. In order to perform this full-color display, a phosphor layer that emits each of the three primary colors is provided. The phosphor particles constituting the phosphor layer are excited by ultraviolet light emitted in the PDP discharge cell to generate visible light of each color. Conventionally, (Y, Gd) BO ₃ : Eu is used as a red phosphor, Zn ₂ SiO ₄ : Mn and (Y, Gd) BO ₃ : Tb are used as a green phosphor, and BaMgAl ₁₀ is used as a blue phosphor. O ₁₇ : Eu and the like are known.

  Here, the moving image quality of the PDP greatly depends on the afterglow characteristics of the red, green, and blue phosphors. If the phosphor has a 1/10 afterglow time (hereinafter simply referred to as afterglow time) of 8 msec or more, it is visually recognized that the light emission has a tail, and the display image quality deteriorates. Further, if it is 4 msec or less, the afterglow becomes difficult to be seen by human eyes, and the display image quality is improved.

Of the phosphors used in PDP, BaMgAl ₁₀ O ₁₇ : Eu, which is usually used as a blue phosphor, has no problem because it has an afterglow time of 1 msec or less. Further, in the red phosphor, the afterglow time of (Y, Gd) BO ₃ : Eu that is usually used is as long as about 10 msec. Therefore, it is necessary to reduce the afterglow time by changing to (Y, Gd) (P, V) O ₄ : Eu or Y ₂ O ₃ : Eu having a shorter afterglow time or mixing them. is there.

On the other hand, in the green phosphor, the afterglow time of commonly used Zn ₂ SiO ₄ : Mn and (Y, Gd) BO ₃ : Tb is as long as 10 msec or more, so (Y, Gd) Al having a short afterglow time. ₃ (BO ₃ ) ₄ : mixing Tb is disclosed in Patent Document 1. Further, as a method for shortening the afterglow time of Zn ₂ SiO ₄ : Mn itself, increasing the concentration of Mn, which is the emission center, is disclosed in Patent Document 2 and the like.

Further, it is known that a green phosphor made of Zn ₂ SiO ₄ : Mn is easily charged to a negative polarity unlike a red phosphor or a blue phosphor, and therefore deteriorates discharge characteristics when used in a PDP. . In order to improve such negative charging, a method of densely laminating a positively charged oxide on the surface of negatively charged Zn ₂ SiO ₄ : Mn until the polarity becomes positive, or a positively charged green phosphor Methods of mixing are disclosed in Patent Document 3 and Patent Document 4.

JP-A-10-195428 JP 2006-274137 A Japanese Patent Laid-Open No. 11-86735 JP 2001-236893 A

  However, with the recent increase in size and definition of televisions, it is necessary to turn on and off pixels at higher speeds, and the deterioration of moving image display quality due to the long afterglow characteristics of green phosphors becomes more prominent. It has become to. For example, a high-definition full-spec high-definition television has 1920 (horizontal) x 1080 (vertical) pixels, approximately six times the number of conventional NTSC pixels, 852 (horizontal) x 480 (vertical). To do. Therefore, since the time required for address discharge per pixel is shortened, there is a problem that the allowable range of discharge characteristics is narrowed and image quality is deteriorated.

On the other hand, when these problems are improved by simply mixing phosphors other than Zn ₂ SiO ₄ : Mn, the luminous efficiency is lowered and the afterglow characteristics are not sufficiently improved. In addition, the method of increasing the Mn concentration of Zn ₂ SiO ₄ : Mn does not sufficiently suppress the decrease in luminance due to the increase in Mn concentration, and the particle surface is likely to be negatively charged. The address discharge characteristics such as an increase cannot be improved.

In addition, with respect to these negative charges, there is a problem that the luminance is further lowered in the method of coating the surface of Zn ₂ SiO ₄ : Mn with a positively charged oxide.

  The present invention solves such a problem, realizes a short afterglow time of the green phosphor, and secures a color reproduction range and is optimal for high-definition image display without luminance deterioration and address voltage increase. The purpose is to provide a PDP.

In order to achieve the above object, the PDP according to the present invention has at least one partition wall for partitioning a plurality of discharge spaces and disposing a pair of substrates transparent at least on the front side so as to form a discharge space between the substrates. An electrode group is arranged on the substrate so that a discharge is generated in a discharge space partitioned by a partition wall and a phosphor layer that emits light by discharge is provided. ₂ comprising a green phosphor layer composed of a mixture of ₂ SiO ₄ : Mn phosphor and (Y, Gd) BO ₃ : Tb phosphor, and Zn element and Mn within 10 nm from the particle surface of the Zn ₂ SiO ₄ : Mn phosphor The ratio of Mn element to the sum of elements (Mn / (Zn + Mn)) is 0.08 to 0.10, and the ratio of the sum of Zn and Mn elements to Si element ((Zn + Mn) / Si) is 1.97 to 2.02, and the mixture ratio of (Y, Gd) BO ₃ : Tb phosphor in the mixture is 50 wt% to 70 wt%.

  According to such a configuration, it is possible to realize a PDP that has no afterimage even in high-definition image display, high luminance, excellent color reproducibility, and reduced address voltage.

  As described above, according to the PDP of the present invention, it is possible to realize a PDP that has no afterimage even in high-definition image display, high luminance, excellent color reproducibility, and reduced address voltage.

It is a disassembled perspective view which shows the structure of PDP in embodiment.

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

(Embodiment)
(1. Configuration of PDP)
FIG. 1 is an exploded perspective view showing the structure of the PDP 10 in the embodiment. As shown in FIG. 1, the PDP 10 includes a front substrate 11 and a back substrate 17. On the glass front substrate 11, a plurality of display electrode pairs 14 are formed in parallel with each other with the scanning electrodes 12 and the sustain electrodes 13. Scan electrode 12 and sustain electrode 13 are formed in a pattern that repeats in the arrangement of scan electrode 12 -sustain electrode 13 -sustain electrode 13 -scan electrode 12. The scanning electrode 12 is formed on a wide transparent electrode 12a made of a conductive metal oxide such as indium tin oxide (ITO), tin oxide (SnO ₂ ), or zinc oxide (ZnO), in order to increase conductivity. A narrow bus electrode 12b containing a metal such as (Ag) is stacked. Similarly, the sustain electrode 13 is formed by laminating a narrow bus electrode 13b on a wide transparent electrode 13a.

Further, a dielectric layer 15 and a protective layer 16 made of magnesium oxide (MgO) are formed so as to cover the display electrode pair 14. The dielectric layer 15 is made of bismuth oxide (Bi ₂ O ₃ ) -based low melting glass or zinc oxide (ZnO) -based low melting glass having a thickness of about 40 μm. The protective layer 16 is a thin film layer made of an alkaline earth metal oxide mainly composed of magnesium oxide (MgO) having a film thickness of about 0.8 μm. The protective layer 16 protects the dielectric layer 15 from ion sputtering and discharge start voltage. Is provided to stabilize the discharge characteristics.

A plurality of parallel data electrodes 18 made of a highly conductive material mainly composed of silver (Ag) or the like are formed on the glass back substrate 17, and a base dielectric layer is formed so as to cover the data electrodes 18. 19 is formed. The underlying dielectric layer 19 may be bismuth oxide (Bi ₂ O ₃ ) -based low-melting glass similar to that of the dielectric layer 15, but titanium oxide (TiO ₂₎ so as to also serve as a visible light reflecting layer. ) A material in which particles are mixed may be used.

  On the base dielectric layer 19, barrier ribs 22 formed in a grid pattern are formed by vertical barrier ribs 22 a and horizontal barrier ribs 22 b. A red phosphor layer 23a, a green phosphor layer 23b, and a blue phosphor layer 23c are formed.

  The partition wall 22 is formed to a height of about 0.12 mm using, for example, a low-melting glass material.

  In the embodiment, the height of the partition wall 22 is 0.1 mm to 0.15 mm and the pitch of the adjacent partition walls 22 is 0.15 mm in accordance with a full high-definition television having a screen size of 42 inches.

The front substrate 11 and the rear substrate 17 are arranged so that the display electrode pair 14 and the data electrode 18 intersect with each other, and the outer periphery thereof is sealed by a sealing material (not shown) such as a frit and discharged inside. A space is formed. A discharge gas containing xenon (Xe) or the like is sealed in the discharge space at a pressure of about 6 × 10 ⁴ Pa. The discharge space is partitioned into a plurality of sections by partition walls 22, and discharge cells 24 are formed at the intersections between the display electrode pairs 14 and the data electrodes 18. These discharge cells 24 discharge and emit light to display an image. The structure of the PDP 10 is not limited to that described above, and the shape of the partition wall 22 may be a stripe shape.

(2. Structure of phosphor material and manufacturing method thereof)
Here, a blue phosphor material of BaMgAl ₁₀ O ₁₇ : Eu having a short afterglow time is used for the blue phosphor layer 23c. The red phosphor layer 23a is made of a red phosphor material containing at least one of (Y, Gd) (P, V) O ₄ : Eu phosphor or Y ₂ O ₃ : Eu phosphor. The green phosphor layer 23b is made of a mixed green phosphor material of Zn ₂ SiO ₄ : Mn and (Y, Gd) BO ₃ : Tb.

  Next, a method for manufacturing each color phosphor material will be described. In the present embodiment, a phosphor material manufactured by a solid phase reaction method is used.

BaMgAl ₁₀ O ₁₇ : Eu, which is a blue phosphor material, is produced by the following method. Barium carbonate (BaCO ₃ ), magnesium carbonate (MgCO ₃ ), aluminum oxide (Al ₂ O ₃ ), and europium oxide (Eu ₂ O ₃ ) are mixed so as to match the phosphor composition. This mixture is fired at 800 ° C. to 1200 ° C. in air, and further fired at 1200 ° C. to 1400 ° C. in a mixed gas atmosphere containing hydrogen and nitrogen.

The red phosphor material (Y, Gd) (P, V) O ₄ : Eu phosphor or Y ₂ O ₃ : Eu phosphor is produced by the following method. Yttrium oxide (Y ₂ O ₃ ), gadolinium oxide (Gd ₂ O ₃ ), vanadium oxide (V ₂ O ₅ ), phosphorus pentoxide (P ₂ O ₅ ) and europium oxide (EuO ₂ ) are matched to the phosphor composition. Mix like so. This mixture is fired at 600 ° C. to 800 ° C. in air, and further fired at 1000 ° C. to 1200 ° C. in a mixed gas atmosphere containing oxygen and nitrogen.

Next, the green phosphor material will be described. In the present embodiment, a mixture of Zn ₂ SiO ₄ : Mn phosphor and (Y, Gd) BO ₃ : Tb phosphor is used as the green phosphor material. In particular, Zn ₂ SiO ₄ : Mn has a ratio (Mn / (Zn + Mn) ratio) of Zn element and Mn element to Mn element at a particle surface of 10 nm or less of 0.08 to 0.10, and Zn element and The ratio of the Si element to the sum of the Mn elements ((Zn + Mn) / Si ratio) is 1.97 to 2.02.

Here, Mn / (Zn + Mn) and (Zn + Mn) / Si at a particle surface of 10 nm or less of Zn ₂ SiO ₄ : Mn can be measured with an XPS apparatus. XPS is an abbreviation for X-ray Photoelectron Spectroscopy, which is called X-ray photoelectron spectroscopy, and is a method for examining the state of elements up to 10 nm near the surface of a substance. Mn / (Zn + Mn) and (Zn + Mn) / Si are values calculated by analyzing Zn, Si, and Mn using an XPS apparatus.

Hereinafter, the manufacturing method of the green phosphor material in the present embodiment will be described in more detail. Zn ₂ SiO ₄ : Mn is produced by using a conventional solid phase reaction method, liquid phase method, or liquid spray method. The solid phase reaction method is a method in which an oxide or carbonate raw material and a flux are fired. The liquid phase method is a method in which a precursor of a phosphor material formed by hydrolyzing an organic metal salt or nitrate in an aqueous solution and adding an alkali or the like as necessary to precipitate is heat-treated. The liquid spray method is a method in which an aqueous solution containing a phosphor material is sprayed into a heated furnace.

Zn ₂ SiO ₄ : Mn used in this embodiment is not particularly affected by the manufacturing method, but here, a manufacturing method by a solid phase reaction method will be described as an example. As a raw material, zinc oxide (ZnO), silicon oxide (SiO ₂ ), manganese carbonate (MnCO ₃ ) is used. Similar to the method using manganese carbonate, manganese hydroxide, manganese nitrate, manganese halide, manganese oxalate, etc. are used as initial materials, and these are subjected to a firing step in the production process, thereby indirectly producing manganese oxide. There is a way to get it. Further, manganese oxide may be used directly.

Further, as a material serving as a zinc supply source in Zn ₂ SiO ₄ : Mn (hereinafter referred to as “Zn material”), high-purity zinc oxide (purity 99% or more) is directly used. In addition to the method using zinc oxide directly as described above, high-purity (purity 99% or more) zinc hydroxide, zinc carbonate, zinc nitrate, zinc halide, zinc oxalate, etc. are used as initial materials. A method of indirectly obtaining the zinc oxide by passing through a baking step in the manufacturing process may be used.

As a material (hereinafter referred to as “Si material”) serving as a silicon supply source in Zn ₂ SiO ₄ : Mn, silicon dioxide having high purity (purity 99% or more) can be used. Alternatively, a silicon hydroxide obtained by hydrolyzing a silicon alkoxide compound such as ethyl silicate may be used.

  The conventional method is characterized in that a phosphor having a high brightness is obtained by mixing the composition ratio of the Si material among the above materials in excess of the stoichiometric ratio. However, unlike the conventional method, the manufacturing method of the present embodiment is characterized in that the composition ratio of the Zn material is mixed in excess of the stoichiometric ratio.

As an example of specific blending of each phosphor material, MnCO ₃ : 0.14 mol, ZnO: 1.88 mol, and SiO ₂ : 1.00 mol.

  For mixing Mn material, Zn material and Si material, industrially used V-type mixers, stirrers and the like can be used, and ball mills, vibration mills, jet mills and the like having a grinding function can also be used. it can.

  Next, the firing process will be described. The mixed powder of the phosphor material is heated to a maximum temperature of 1200 ° C. in about 6 hours after the start of firing in the air atmosphere, and is fired for 4 hours while maintaining this maximum temperature, and then about 12 hours in the normal air atmosphere. Allow to cool down. In this way, green phosphor material powder is obtained.

  Note that the atmosphere during firing is not limited to an air atmosphere, and may be a nitrogen atmosphere or a mixed atmosphere of nitrogen and hydrogen. The maximum temperature is preferably between 1100 ° C. and 1350 ° C., but there is no problem even if the maximum temperature maintenance time, temperature increase time, temperature decrease time, etc. are appropriately changed.

In the present embodiment, the ratio of Zn ₂ SiO ₄ : Mn to the sum of Zn element and Mn element with respect to Mn element at the particle surface of 10 nm or less, and the ratio of Si element to the sum of Zn element and Mn element are as follows: Adjustment is made by controlling the mixing ratio of the Mn material, Zn material and Si material, firing conditions, and the like.

Next, the other green fluorescence (Y, Gd) BO ₃ : Tb is produced by the following method. Yttrium oxide (Y ₂ O ₃ ), gadolinium oxide (Gd ₂ O ₃ ), boron oxide (B ₂ O ₃ ), and terbium oxide (Tb ₄ O ₇ ) are mixed so as to match the phosphor composition. The mixture is fired at 1100 ° C. to 1200 ° C. in air, and further fired at 1200 ° C. to 1400 ° C. in a mixed gas atmosphere containing oxygen and nitrogen.

Zn ₂ SiO ₄ : Mn thus produced and (Y, Gd) BO ₃ : Tb are mixed to produce a green phosphor.

(3. Actual machine evaluation test results)
The actual evaluation results of the PDP are shown in Table 1, and each evaluation was evaluated as follows.

(3.1 Luminance evaluation)
The PDP 10 in which the green phosphor layer 23b is formed using the above-described green phosphor is manufactured. A plasma display device is manufactured by connecting a drive circuit or the like to the PDP 10. In this plasma display device, only the green phosphor layer 23b was caused to emit light and the luminance was measured. The luminance is expressed as a relative value when the luminance of the comparative product 1 as a conventional product is set to 100, and the relative luminance is 85 or more.

(3.2 Color reproduction range evaluation)
The color reproduction range refers to the area of the triangle formed by the chromaticity of each red, green, and blue light that is emitted as a single color on the xy chromaticity coordinates in the plasma display device. Yes. The color reproduction range is expressed as a relative value when the color reproduction range of the comparative product 1 as a conventional product is set to 100. If this relative color reproduction range is 90 or more, it satisfies the chromaticity standard of HDTV and is practical. Above preferred.

(3.3 Evaluation of green afterglow characteristics)
The green afterglow characteristic is a comparison with the conventional product, measuring the time when the light emission amount becomes 1/10 of the maximum value, with the time when the light emission amount at the end of the sustain discharge reaches the maximum value as 0 in the plasma display device. When the afterglow characteristic of product 1 was shorter than 9.2 ms, it was determined that there was an effect of improving the afterglow characteristic.

(3.4 Evaluation of address discharge characteristics)
The address discharge characteristics are measured by measuring the voltage applied to the address electrode (hereinafter referred to as address voltage) necessary for generating stable address discharge in the plasma display device, and the difference from the comparative product 1 as a conventional product is +5 V or less. If so, it was determined that there was no problem in practical use.

  However, in stereoscopic image display and high-definition televisions that require high-speed addresses, the power consumption due to address discharge increases in proportion to the square of the address voltage, so the address voltage differs from the comparative product, which is a conventional product. -1V or less is required.

(3.5 Evaluation results)
Table 1 shows the compositions of the green phosphors of Examples 1 to 6 and Comparative Examples 1 to 4, and the evaluation results of PDP 10 using the compositions. As shown in Table 1, the comparative example and the example show that Zn ₂ SiO ₄ : Mn has a particle surface of 10 nm or less, Mn / (Zn + Mn), and (Zn + Mn) / Si and (Y, Gd) BO ₃ : Tb mixed. The ratio is different.

Comparative Example 1 shows a conventional case of Zn ₂ SiO ₄ : Mn, and all other Comparative Examples or Examples are evaluated as relative values with respect to Comparative Example 1.

As shown in Table 1, in Examples 1 to 5, the relative luminance is 90 or more, the color reproduction range is 90 or more, the afterglow characteristic is 7 ms or less applicable to a high-definition full-spec high-definition television, and the address voltage is It can suppress to the comparative example 1 or less. Therefore, in the PDP 10 using the green phosphor mainly composed of Zn ₂ SiO ₄ : Mn, there are problems such as a long afterglow time, which is a conventional problem, luminance deterioration due to positive charging, and address voltage increase. It is possible to solve the problem and realize an optimal PDP for high-definition full-spec image display.

Further, the red phosphor layer 23a includes at least one of (Y, Gd) (P, V) O ₄ : Eu phosphor or Y ₂ O ₃ : Eu phosphor, and the blue phosphor layer 23c is BaMgAl _10. When the O ₁₇ : Eu phosphor is included, the afterglow time can be shortened in all of the red phosphor layer 23a, the green phosphor layer 23b, and the blue phosphor layer 23c.

  The PDP of the present invention provides a PDP that realizes high-quality moving image display quality, and is useful for a large-screen high-definition image display device.

10 PDP
DESCRIPTION OF SYMBOLS 11 Front substrate 12 Scan electrode 12a, 13a Transparent electrode 12b, 13b Bus electrode 13 Sustain electrode 14 Display electrode pair 15 Dielectric layer 16 Protective layer 17 Rear substrate 18 Data electrode 19 Base dielectric layer 22 Partition 22a Vertical partition 22b Horizontal partition 23 Phosphor layer 23a Red phosphor layer 23b Green phosphor layer 23c Blue phosphor layer 24 Discharge cell

Claims (2)

At least a pair of substrates transparent at least on the front side are disposed opposite to each other so that a discharge space is formed between the substrates, and a partition for partitioning the discharge space into a plurality is disposed on at least one substrate, and is partitioned by the partition A plasma display panel in which an electrode group is arranged on a substrate so as to generate a discharge in a discharge space and a phosphor layer that emits light by discharge is provided, wherein the phosphor layer includes a Zn ₂ SiO ₄ : Mn phosphor ( The ratio of Mn element to the sum of Zn element and Mn element within 10 nm from the particle surface of the Zn ₂ SiO ₄ : Mn phosphor, comprising a green phosphor layer composed of a mixture of Y, Gd) BO ₃ : Tb phosphor (Mn / (Zn + Mn)) is 0.08 to 0.10, and the ratio of the sum of Zn element and Mn element to Si element ((Zn + Mn) / Si) is 1.97 to 2.02, Furthermore, the mixing ratio of the (Y, Gd) BO ₃ : Tb phosphor in the mixture is 50 wt% to 70 wt%. The phosphor layer includes a red phosphor layer including at least one of (Y, Gd) (P, V) O ₄ : Eu phosphor or Y ₂ O ₃ : Eu phosphor, and BaMgAl ₁₀ O ₁₇ : Eu fluorescence. The plasma display panel according to claim 1, further comprising a blue phosphor layer including a body.

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