KR100667937B1 - Plasma display panel - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel. More specifically, the present invention relates to a plasma display panel, and more particularly to a first substrate and a second substrate disposed opposite to each other, address electrodes provided on the first substrate, and a second substrate. A plurality of display electrodes arranged in a space between the first substrate and the second substrate and formed in a partition wall disposed on the first substrate to partition the plurality of discharge cells and a discharge cell partitioned by the partition wall. The plasma display panel includes a phosphor layer, wherein the blue phosphor layer-forming discharge cell of the discharge cells is larger than at least one of the red or green phosphor layer-forming discharge cells, and the blue phosphor layer includes a calcium magnesium silicate-based blue phosphor.

The plasma display panel of the present invention can improve the luminance of the calcium magnesium silicate-based blue phosphor and improve the permanent persistence and color reproduction.

Plasma Display Panel, Calcium Magnesium Silicate, Blue Phosphor, Permanent Afterimage, Color Reproduction

Description

Plasma Display Panel {PLASMA DISPLAY PANEL}

1 is a partially exploded perspective view of a plasma display panel according to an embodiment of the present invention;

FIG. 2 is a plan view of the plasma display panel shown in FIG. 1.

[Industrial use]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a plasma display panel with improved luminance and improved afterimage and color reproducibility of calcium magnesium silicate-based blue phosphor.

[Private Technology]

A plasma display panel is a display device using a plasma phenomenon. When a potential difference is applied between two electrodes spaced apart in a gas atmosphere in a non-vacuum state, a discharge is generated, which is called a gas discharge phenomenon.

A plasma display element is a flat panel display element which applied such gas discharge phenomenon to image display. The plasma display panel which is generally used at present is a reflective AC drive plasma display panel, and in the case of a back substrate structure, a phosphor layer is formed on a partition wall.

The plasma display panel, like other flat panel display devices such as a fluorescent display tube (VFD) or a field emission display (FED), is called a rear substrate and a front substrate (for convenience, referred to as a first substrate and a second substrate, respectively) at an arbitrary distance. ) Are formed to be substantially parallel to each other to form an outer appearance thereof. At this time, the substrates are joined by a bonding material disposed along a circumference therebetween to form a discharge cell in a vacuum state.

In the vacuum discharge cell, a discharge gas containing about 5 to 12% of Xe or the like, which is a main light emitting gas, is injected to cause a gas discharge phenomenon.

On the other hand, the phosphor used in the plasma display panel uses red, green and blue phosphors, and the direction to improve the fluorescent material used in the phosphor application products such as CRT phosphors, fluorescent lamps that have been used since the early development of the plasma display panel As a result, studies have been made on phosphors. In order for a phosphor to be used in a plasma display panel, it must be excellent in luminescence brightness, luminous efficiency and color purity, have a short afterglow time, and in particular, do not cause deterioration of the phosphor by heat or ultraviolet rays.

Currently, blue phosphors widely used in plasma display panels include barium magnesium aluminate-based phosphors. However, the barium magnesium aluminate-based blue phosphor has a characteristic of deterioration while discharge is continuously occurring, and thus, a lifespan characteristic of the phosphor is deteriorated and there is a problem of deteriorating the lifetime of the entire panel.

In order to solve this problem, studies have been conducted on calcium magnesium silicate-based phosphors having excellent color characteristics, vacuum ultraviolet light deterioration characteristics, and lifetime characteristics, but calcium magnesium silicate-based phosphors have a problem of lowering luminance characteristics.

U. S. Patent No. 6,198, 463 describes a driving method in which the interval between the sustain discharge waveforms of the scan electrodes and the sustain electrodes is 5 mW to 0.3 mW in order to reduce the probability of misdischarge, but the luminance of the plasma display panel is changed using the driving method. There is no study to improve.

The present invention is to solve the above problems, an object of the present invention is to improve the brightness of the calcium magnesium silicate-based blue phosphor by using an asymmetric structure of the partition wall or electrode, and to improve the afterimage and color reproducibility plasma display panel To provide.

In order to achieve the above object, the present invention provides a plurality of first and second substrates facing each other, address electrodes provided on the first substrate, and a plurality of pairs of scan electrodes and sustain electrodes provided on the second substrate. Red, green, and blue phosphor layers formed in display electrodes, a partition disposed in a space between the first substrate and the second substrate and disposed in the first substrate to partition a plurality of discharge cells, and in the discharge cells partitioned by the partition walls. And a blue phosphor layer-forming discharge cell of the discharge cells is greater than at least one of red or green phosphor layer-forming discharge cells, wherein the blue phosphor layer comprises a calcium magnesium silicate (CMS) -based blue phosphor. do.

More preferably, the size of the blue phosphor layer-forming discharge cell is 105 to 150% of the size of at least one of the red or green phosphor layer-forming discharge cells.

The CMS-based blue phosphor layer may further contain a barium magnesium aluminate (BAM) -based blue phosphor, wherein the discharge cell in which the blue phosphor layer is formed is at least one of discharge cells in which a red or green phosphor layer is formed. A larger surface area over which the phosphor is applied may be formed.

The barrier ribs may be formed in a stripe shape along an address electrode direction, and the barrier rib may include first barrier members positioned along an address electrode direction, and second barrier members intersecting the first barrier members. The discharge cells may be partitioned by a pair of first partition members and a pair of second partition members.

In this case, the width W ₁ (B) of the blue discharge cells among the discharge cells is greater than the width W ₁ (R) of the red discharge cells or the width W ₁ (G) of the green discharge cells, or the blue discharge cells of the discharge cells. The width of W ₁ (B) is greater than the width of the red discharge cell W ₁ (R) or the width of the green discharge cell W ₁ (G) and the length of the blue discharge cell L ₁ (B) is the length of the red discharge cell L ₁ Or may be formed longer than the length L ₁ (G) of the green discharge cell. At this time, the area of the display electrode corresponding to the discharge cell in which the blue phosphor layer is formed among the discharge cells is formed to be larger than the area of the display electrode corresponding to the discharge cell in which the green or red phosphor layer is formed. A pair of bus electrodes corresponding to the discharge cells and protruding electrodes extending from the bus electrodes toward the center of each discharge cell are formed so as to face each other, and the gaps between the protruding electrodes are substantially the same.

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

1 is a partially exploded perspective view of a plasma display panel according to an embodiment of the present invention, Figure 2 is a plan view of the plasma display panel shown in FIG.

Referring to the drawings, in the plasma display panel (hereinafter referred to as 'PDP') according to the present embodiment, the first substrate 2 and the second substrate 4 are disposed to face each other at random intervals, and the space between the two substrates is provided. Discharge cells 8R, 8G, and 8B partitioned by partition 6 are provided to implement an arbitrary color image with visible light emission by an independent discharge mechanism of each discharge cell 8.

Looking at the configuration thereof, first, the address electrodes 10 are formed on the inner surface of the second substrate 4 along one direction (the X direction in the drawing), and cover the address electrodes 10 with the second substrate ( The dielectric layer 12 is formed over the entire inner surface of 4). For example, the address electrode 10 is formed in a stripe pattern and formed in parallel with a neighboring address electrode 10 at a predetermined interval.

On the dielectric layer 12 is formed a partition 6, in particular a matrix 6 in the form of a matrix, and the red, green, and blue phosphor layers 14R, 14G across four sides of the partition 6 and the top surface of the dielectric layer 12. 14B). In this embodiment, the blue phosphor layer 14B is formed by applying calcium magnesium silicate series blue phosphor. The partition wall 6 consists of the 1st partition wall member 6a according to the address electrode direction, and the 2nd partition wall member 6b along the direction (X direction of drawing) orthogonal to an address electrode, Comprising: 1st, 2nd partition member The interior of the discharge cell 8 surrounded by 6a and 6b is filled with discharge gas (Ne-Xe mixed gas).

On the inner surface of the first substrate 2 facing the second substrate 4, a display electrode 20 including scan electrodes 16 and sustain electrodes 18 is formed along a direction orthogonal to the address electrodes 10. The transparent dielectric layer and the passivation layer, which are not shown, are disposed on the entire inner surface of the first substrate 2 while covering the display electrodes 20.

In this embodiment, the display electrode 20 is formed in a stripe pattern, for example, and pairs of bus electrodes 16a and 18a corresponding to each discharge cell 8, and each discharge cell 8 from the bus electrodes 16a and 18a. It consists of protruding electrodes 16b and 18b extending inwardly and formed to face each other. The protruding electrodes 16b and 18b may be transparent electrodes such as indium tin oxide (ITO), and it is preferable to use a conventional metal electrode as the bus electrodes 16a and 18a. It is also preferable that the gaps between the protruding electrodes are substantially the same.

As a result, an address voltage Va is applied between the address electrode 10 and the scan electrode 16 to select a discharge cell for emitting light, and a sustain voltage Vs is applied between the scan electrode 16 and the display electrode 18. When applied, the vacuum gas is emitted while the discharge gas in the discharge cell 8 causes plasma discharge, and the vacuum ultraviolet light excites the phosphor layer 14 and converts it into visible light, thereby enabling color display.

The blue phosphor layer of the plasma display panel of the present invention includes a conventional calcium magnesium silicate-based blue phosphor, preferably Ca _(w) Mg _(x) Si _(y) O _(z) : Eu [w, x, y is an integer of 1 to 20, z is an integer of 1 to 30; and includes at least one calcium magnesium silicate-based blue phosphor, more preferably CaMgSi ₂ O ₆ : Eu, Ca ₃ MgSi ₂ O ₈ : At least one selected from Eu and Ca ₂ MgSiO ₄ : Eu.

In addition, the blue phosphor composition of the present invention may include a mixture of calcium magnesium silicate-based blue phosphor and barium magnesium aluminate (BAM) -based blue phosphor. The barium magnesium aluminate-based blue phosphor is at least one selected from BaMgAl ₁₀ O ₁₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, and BaMgAl ₁₄ O ₂₃ : Eu. In this case, the mixing ratio of the calcium magnesium silicate-based blue phosphor and the barium magnesium aluminate-based blue phosphor included in the blue phosphor layer is preferably in a weight ratio of 2: 8 to 7: 3, and more preferably 2: 8 to 6: 4. desirable. When the mixing ratio is less than 2: 8, the permanent afterimage property is deteriorated, which is not preferable. When the mixing ratio is greater than 7: 3, the luminance is lower than that when only the barium magnesium aluminate-based blue phosphor is used.

The calcium magnesium silicate (CMS) -based blue phosphor exhibits excellent lifespan characteristics compared to barium magnesium aluminate (BAM) -based blue phosphors, but has lower luminance characteristics than the barium magnesium aluminate-based blue phosphors. In order to satisfy the lifespan characteristics and the luminance characteristics at the same time, the size of the blue phosphor layer forming discharge cell should be made larger than that of the red phosphor layer forming discharge cell by asymmetrically installing the partition position and the electrode.

More specifically, the size of the blue phosphor layer-forming discharge cell is preferably 105% to 150%, more preferably 110 to 130% of the size of at least one of the red or green phosphor layer forming discharge cells. If it is less than 105%, the effect is small, which is not preferable. If it exceeds 150%, the overall efficiency is greatly reduced, which is not preferable. The size of the discharge cell can be adjusted by changing the length and width.

The blue phosphor layer is formed by dispersing a blue phosphor in a vehicle in which a binder resin is dissolved in a solvent to prepare a phosphor paste, and then applying the blue phosphor to a discharge cell of a plasma display panel. Examples of the binder resin and the solvent used to prepare the phosphor paste are as described below, but are not limited thereto.

As the binder resin, a cellulose resin, an acrylic resin, or a mixture thereof may be used. As the cellulose resin, for example, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxy methyl cellulose, hydroxy ethyl cellulose, hydroxy propyl cellulose, hydroxy ethyl propyl cellulose, or a mixture thereof may be used. As said acrylic resin, For example, poly methyl methacrylate, poly isopropyl methacrylate, poly isobutyl methacrylate, or methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, Hexyl methacrylate, 2-ethyl hexyl methacrylate, benzyl methacrylate, dimethyl amino ethyl methacrylate, hydroxy ethyl methacrylate, hydroxy propyl methacrylate, hydroxy butyl methacrylate, phenoxy 2- Hydroxy propyl methacrylate, glycidyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethyl hexyl acrylate, benzyl acrylate, dimethyl amino ethyl acrylate , With hydroxy Acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, phenoxy copolymer, or a mixture of acrylic monomers such as 2-hydroxypropyl acrylate, glycidyl acrylate can be used. In some cases, the paste may comprise a small amount of inorganic binder. Preferably, the content of the binder resin may be 2 to 8% by weight based on the total weight of the phosphor paste.

Alcohol, ether, ester, or a mixture thereof may be used as the solvent, more preferably butyl cellosolve (BC), butyl carbitol acetate (BCA), terpineol (terpineol) or mixtures thereof and the like can be used. If the content of the solvent is too high or too low, the flow characteristics of the composition is not appropriate, the process of forming a blue phosphor layer may not be easy. In consideration of this point, the content of the solvent may be 25 to 75 wt% based on the total weight of the phosphor paste.

The phosphor paste may further include other additives to improve flow characteristics, process characteristics, and the like. As the additive, for example, various additives such as a photosensitizer, a dispersant, a silicone-based antifoaming agent, a leveling agent, a plasticizer, an antioxidant, and the like may be used alone or in combination, all of which are all used in the art. Commercially available to those skilled in the art.

The red, green, and blue discharge cells 8R, 8G, and 8B gather together to form one pixel by changing the structure of the partition wall 6 partitioning the discharge cells 8 according to the characteristics of the blue-based phosphor. The structure complementing the luminance of the discharge cell is applied. In this embodiment, the structure consists of varying the area of the blue discharge cells 8G while minimizing the change of components other than the partition wall 6.

More specifically, as shown in FIG. 2, the first and second partition members 6a and 6b constituting the partition wall 6 form a predetermined pattern throughout the second substrate 4. That is, the first and second partition members 6a and 6b partition discharge cells forming red, green, and blue phosphor layers while repeating the order along the extension direction of the display electrode. At this time, the red or green discharge is made by increasing the width (that is, the value measured along the address direction) and the length (that is, the value measured along the direction orthogonal to the address direction) of the blue discharge cells 8B among the discharge cells. The area is formed larger than the cells 8R and 8G. On the other hand, only the width W ₁ (B) of the blue discharge cells may be made larger than the width W ₁ (R) or W ₁ (G) of the red or green discharge cells, and only the length L ₁ (B). The length of the red or green discharge cells may be larger than that of L ₁ (R) and L ₁ (G).

 In the present embodiment, the widths of the display electrodes 16B and 18B corresponding to the discharge cells in which the blue phosphor layer is formed are increased in correspondence to the increase in the area of the discharge cells in which the blue phosphor layer is formed, so that the areas of the discharge cells having different areas are increased. It was formed larger than the area of the corresponding display electrodes 16R, 16G, 18R, and 18G.

In the plasma display panel of the present invention, the luminance of the calcium magnesium silicate-based blue phosphor may be improved and the afterimage and color reproduction may be improved by making the blue phosphor layer-forming discharge cell larger than at least one of the red or green phosphor layer-forming discharge cells.

Hereinafter, preferred embodiments of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

EXAMPLE

Comparative Example 1

A phosphor slurry was prepared by mixing 6 parts by weight of ethyl cellulose as a binder and 40 parts by weight of BaMgAl ₁₀ O ₁₇ : Eu as a blue phosphor with respect to 100 parts by weight of a mixed solvent of butylcarbitol acetate and terpineol 3: 7 by weight.

The prepared phosphor slurry was applied inside the discharge cell of the first substrate on which the partition wall was formed. At this time, the discharge cells are all the same size.

The first substrate coated with the phosphor slurry was dried and baked at 120 ° C. to form a blue phosphor layer.

Also, phosphor layers of (Y, Gd) BO ₃ : Eu and ZnSiO ₄ : Mn were formed in the red and green discharge cells in the same manner as the method of forming the blue phosphor layer.

The plasma display panel was manufactured by assembling, sealing, evacuating, injecting, and aging the panel using the first substrate on which the phosphor layer was formed.

Comparative Example 2

A plasma display panel was manufactured in the same manner as in Comparative Example 1 except that a partition wall was formed such that the size of the blue phosphor layer forming discharge cell was 120% of the size of the red phosphor layer forming discharge cell.

Comparative Example 3

A plasma display panel was manufactured in the same manner as in Comparative Example 1 except that CaMgSi ₂ O ₆ : Eu was used as a blue phosphor.

Example 1

Plasma was formed so that the size of the blue phosphor layer forming discharge cell was 120% of the size of the red phosphor layer forming discharge cell, and the plasma was prepared in the same manner as in Comparative Example 1 except that CaMgSi ₂ O ₆ : Eu was used as the blue phosphor. The display panel was manufactured.

Example 2

A barrier rib was formed so that the size of the blue phosphor layer forming discharge cell was 120% of the size of the red phosphor layer forming discharge cell, and CaMgSi ₂ O ₆ : Eu and BaMgAl ₁₄ O ₂₃ : Eu were mixed at 5: 5 as a blue phosphor. A plasma display panel was manufactured in the same manner as in Comparative Example 1 except that it was used.

After lighting only the blue phosphor layer of the plasma display panels of Comparative Examples 1 to 3 and Example 1, the luminance and color coordinates of the blue light emitted from the plasma display panel were measured using a contact luminance meter (CA-100). Color reproduction was evaluated. In addition, the effect of permanent afterimage improvement was measured from the change in color temperature. Permanent afterimage improvement effect was evaluated by accelerating aging by making a specific pattern for a specific time and measuring the difference in color temperature and luminance of display and non-display. Generally, when the color temperature is about 9000K, the luminance difference is more than 5 cd / m ² and the color temperature difference is more than 300K, and permanent afterimage is observed. The color coordinates and permanent afterimage measurement results of the blue phosphor are shown in Table 1 below.

Color coordinates Luminance Permanent afterimage appearance time Example 1 (0.147, 0.040) 100% 100hr Comparative Example 1 (0.147, 0.060) 100% 6hr Comparative Example 2 (0.147, 0.060) 120% 6hr Comparative Example 3 (0.147, 0.040) 80% 100hr

As shown in Table 1, in Example 1 of the present invention, the Y value of the color coordinates is lower than that of Comparative Examples 1 to 3, which is more biased toward the lower left side of the chromaticity diagram, and thus, the color reproduction area becomes wider. In Comparative Example 3, the same color coordinates as in Example 1 were obtained, but the luminance was lower than that in Example 1. As a result, in Example 1, color reproducibility (based on NTSC) was 5% or more, and permanent afterimage was improved by 15 times or more as compared with Comparative Examples 1 to 3.

The plasma display panel of the present invention can improve the luminance of the calcium magnesium silicate-based blue phosphor and improve the permanent persistence and color reproduction.

Claims (14)

A first substrate and a second substrate disposed to face each other; A plurality of display electrodes provided on the first substrate and the address electrodes on the second substrate, and the scan electrodes and the sustain electrodes paired with each other; A partition wall disposed in a space between the first substrate and the second substrate and installed on the first substrate to partition a plurality of discharge cells; A red, green, and blue phosphor layer formed in the discharge cell partitioned by the partition wall;  The size of the blue phosphor layer-forming discharge cell of the discharge cells is 105 to 150% of the size of at least one of the red or green phosphor layer-forming discharge cells, The blue phosphor layer includes a barium magnesium aluminate-based phosphor in a weight ratio of 2: 8 to 7: 3 together with calcium magnesium silicate-based blue phosphor. delete The method of claim 1, wherein the calcium magnesium silicate-based blue phosphor is Ca _(w) Mg _(x) Si _(y) O _(z) : Eu [w, x, y is an integer of 1 to 20, z is 1 to 30 Integer of the plasma display panel]. delete The plasma display panel of claim 1, wherein the barium magnesium aluminate-based blue phosphor is one or more selected from BaMgAl ₁₀ O ₁₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, and BaMgAl ₁₄ O ₂₃ : Eu. delete The plasma display apparatus of claim 1, wherein the barrier ribs have a stripe shape along an address electrode direction. The pair of first barrier members of claim 1, wherein the barrier rib comprises first barrier members positioned along an address electrode direction, and second barrier members intersecting the first barrier members. And the discharge cells are partitioned by a second partition member of the plasma display panel. The plasma display panel of claim 8, wherein the width W ₁ (B) of the blue discharge cells is greater than the width W ₁ (R) of the red discharge cell or the width W ₁ (G) of the green square cell. The width W ₁ (B) of the blue discharge cell among the discharge cells is greater than the width W ₁ (R) of the red discharge cell or the width W ₁ (G) of the green discharge cell, and the length of the blue discharge cell. L ₁ (B) is a plasma display panel longer than the length L ₁ (R) of the red discharge cell or the length L ₁ (G) of the green discharge cell. The plasma display panel of claim 1, wherein an area of the display electrode corresponding to the discharge cell in which the blue phosphor layer is formed is larger than an area of the display electrode corresponding to the discharge cell in which the green or red phosphor layer is formed. 12. The display device of claim 11, wherein the display electrode includes a bus electrode corresponding to each pair of discharge cells and protruding electrodes extending from the bus electrode toward the center of each discharge cell so as to face each other. The gap is the same plasma display panel. The plasma display panel of claim 1, wherein the size of the blue phosphor layer-forming discharge cell is 110 to 130% of the size of at least one of the red or green phosphor layer-forming discharge cells. The plasma display panel of claim 1, wherein the blue phosphor layer comprises calcium magnesium silicate-based blue phosphor and barium magnesium aluminate-based blue phosphor in a weight ratio of 2: 8 to 6: 4.

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