KR20060101677A - Green phosphor composition for plasma display panel and plasma display panel prepared from the same - Google Patents

Abstract

The present invention relates to a green phosphor composition for a plasma display panel and a plasma display panel manufactured therefrom, wherein the green phosphor composition includes a magnesium aluminum oxide (MAO) -based phosphor and a yttrium (Y) -based phosphor.

The plasma display panel of the present invention includes a green phosphor layer formed from a green phosphor composition including MAO-based phosphors and Y-based phosphors in an optimal mixing ratio, thereby maintaining excellent luminance as well as improved color reproduction and permanent image retention.

Plasma Display Panel, Green Phosphor Composition, Luminance, Permanent Afterimage, Color Reproduction

Description

Green phosphor composition for plasma display panel and plasma display panel manufactured therefrom {GREEN PHOSPHOR COMPOSITION FOR PLASMA DISPLAY PANEL AND PLASMA DISPLAY PANEL PREPARED FROM THE SAME}

1 is an exploded perspective view showing an example of a plasma display panel of the present invention.

[Industrial use]

The present invention relates to a green phosphor composition for a plasma diplay panel (PDP) and a plasma display panel manufactured therefrom, and more particularly, to improve luminance by supplementing the luminance of a magnesium aluminum oxide (MAO) -based phosphor. The present invention relates to a green phosphor composition for a plasma display panel, which is not only retained but also has improved afterimage and color reproducibility, and a plasma display panel manufactured therefrom.

[Private Technology]

The plasma display panel is a display device using a plasma phenomenon, and discharge occurs when at least one potential difference is applied between two spatially separated contacts in a gas atmosphere in a non-vacuum state, 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. A plasma display panel generally used at present is a reflective AC drive plasma display panel, and in the case of a bottom plate structure, a phosphor layer is formed on a partition wall.

In order for the plasma display panel to exhibit a uniform and stable discharge, the surface potential of the phosphor is high, and high temperature gaseous anions must collide with the phosphor layer at high speed. The higher the surface potential of the phosphor, the greater the potential difference between the phosphor and the anion, thereby realizing a plasma discharge exhibiting uniform and stable light emission characteristics. These phosphors are manufactured by mixing solid powder raw materials and firing them at a high temperature. The surface potential of the phosphors may vary depending on the composition and raw material properties of the phosphors thus prepared.

Particularly, Zn ₂ SiO ₄ : Mn green phosphors used for plasma display panels are prepared by mixing solid raw materials of ZnO, SiO ₂ , MnCO ₃ , where an intermediate product or a product having a nonuniform composition ratio is formed, and red and blue phosphors Unlike, the surface potential has a negative charge.

This affects the potential of the surface of the phosphor layer in the panel, and builds up wall charges during reset discharge, which is a characteristic of AC plasma display operation during actual discharge. Since the surface potential of the phosphor layer has a negative charge unlike red and blue phosphors, Absorption and offset of cations, which are wall charges accumulated on the surface, results in an increase in the address discharge voltage added for discharge in the next address discharge period. That is, high discharge voltages are required with surface potentials lower than those of red and blue. Therefore, studies are being conducted to increase the surface potential of the green phosphor to have a surface potential similar to that of the red and blue phosphors.

In order to solve this problem, Korean Patent Publication No. 2001-62387 describes a green phosphor in which Zn ₂ SiO ₄ : Mn and YBO ₃ : Tb are mixed. However, this green phosphor has a problem that the color purity and life is reduced. In addition, Korean Patent Laid-Open Publication No. 2000-60401 describes the mixing of Zn ₂ SiO ₄ with a material having a positive potential of magnesium oxide and zinc oxide. However, the phosphor produced by this method also improves the discharge stability by increasing the charge amount, but there is a problem that the color purity is lowered.

The present invention is to solve the above problems, an object of the present invention is to complement the low luminance of the magnesium aluminum oxide (MAO) -based phosphor to maintain the excellent brightness as well as to improve the permanent afterimage and color reproduction green color for plasma display panel It is to provide a phosphor composition.

Another object of the present invention is to provide a plasma display panel which not only maintains excellent luminance but also improves permanent image retention and color reproduction.

In order to achieve the above object, the present invention provides a green phosphor composition for a plasma display panel comprising a magnesium aluminum oxide (MAO) series phosphor and a yttrium (Y) series phosphor.

The present invention also provides a plasma display panel including a green phosphor layer formed by applying the green phosphor composition to a discharge cell.

Hereinafter, the present invention will be described in more detail.

According to a first preferred embodiment of the present invention, there is provided a green phosphor composition comprising a MAO-based phosphor and a Y-based phosphor.

As the MAO-based phosphor, a phosphor represented by MgAl _x O _y : Mn (1 ≦ _x ≦ 10, 1 ≦ _y ≦ 30) may be used, and preferably MgAl ₂ O ₃ : Mn. In addition, YBO ₃ : Tb, (Y, Gd) BO ₃ : Tb and the like may be used as the Y-based phosphor, preferably YBO ₃ : Tb. The MAO-based phosphors are superior to the Zn-based phosphors used in conventional green phosphors, but have excellent color characteristics and vacuum ultraviolet ray deterioration characteristics, but have lower luminance characteristics than Zn-based phosphors. By mixing and using the mixing ratio, it is possible to compensate for the low luminance of the MAO-based phosphors and to improve permanent afterimage and color reproduction.

It is preferable that the mixing ratio of MAO series fluorescent substance and Y series fluorescent substance contained in the said green fluorescent substance layer is 70: 30-40: 60 by weight ratio, and it is more preferable that it is 50: 50-40: 60. The mixing ratio can achieve excellent luminance characteristics, color reproducibility, and permanent afterimage improvement effects within the above range, but when the mixing ratio is out of the mixing ratio range, the luminance characteristics are deteriorated.

According to a second embodiment of the present invention, a first substrate and a second substrate disposed opposite to each other; A plurality of display electrodes provided on the first substrate, the address electrodes provided on the first substrate, and a pair of scan electrodes and sustain electrodes; 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; And respective red, green, and blue phosphor layers formed in the discharge cells partitioned by the partition walls, wherein the green phosphor layer is formed by applying a green phosphor composition including a MAO-based phosphor and a Y-based phosphor. Provide a display panel.

1 is an exploded perspective view showing an example of a plasma display panel of the present invention. However, the plasma display panel of the present invention is not limited to the structure of FIG. 1. Referring to the drawings, in the conventional plasma display panel, address electrodes 3 are formed in one direction (Y direction in the drawing) on the first substrate 1, and the first substrate covers the address electrodes 3. The dielectric layer 5 is formed in front of (1). A partition wall 7 is formed between the address electrodes 3 on the dielectric layer 5, and phosphor layers 9 of red (R), green (G), and blue (B) colors are formed between the partition walls 7. ) Is located. In this case, the green phosphor layer 9 includes a green phosphor composition including a MAO-based phosphor and a Y-based phosphor.

In addition, a pair of transparent electrodes 13a and bus electrodes 13b may be disposed on one surface of the second substrate 11 opposite to the first substrate 1 in a direction orthogonal to the address electrode 3 (the X direction in the drawing). The display electrodes 13 may be formed, and the transparent dielectric layer 15 and the passivation layer 17 may be disposed on the entirety of the second substrate 11 while covering the display electrodes 13. Any one of the paired display electrodes 13 is called a scan electrode and the other is called a sustain electrode. As a result, the intersection of the address electrode 3 and the display electrode 13 constitutes a discharge cell.

With this configuration, the address discharge is applied by applying the address voltage Va between the address electrode 3 and any one of the display electrodes 13, and again discharged between the pair of display electrodes (scan electrode and sustain electrode). When the sustain voltage Vs is applied, vacuum ultraviolet rays generated during sustain discharge excite the phosphor layer 9 to emit visible light through the transparent front substrate 11.

The green phosphor layer 9 disperses a green phosphor composition comprising a MAO-based phosphor and a Y-based phosphor in a vehicle in which a binder resin is dissolved in a solvent to prepare a phosphor paste, and then apply the phosphor to a discharge cell of a plasma display panel. To form. The green phosphor composition is as described above.

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 Copolymers of acrylic monomers such as methyl acrylate, hydroxy propyl acrylate, hydroxy butyl acrylate, phenoxy 2-hydroxy propyl acrylate, glycidyl acrylate, and the like, or mixtures thereof may be used. In some cases, the composition 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 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 green 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 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.

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 1

6 parts by weight of ethyl cellulose as a binder is mixed with 100 parts by weight of the mixed solvent of butylcarbitol acetate and terpineol, and the weight ratio of 70:30 is MgAl ₂ O ₃ : Mn and YBO ₃ : Tb, which are green phosphors. 40 parts by weight of the mixed phosphor was mixed to prepare a green phosphor paste.

The prepared phosphor slurry was applied to the inside of the discharge cell of the first substrate on which the partition wall was formed, and the first substrate on which the phosphor paste was applied was dried and fired to prepare a green phosphor layer.

In the same manner, phosphor layers of (Y, Gd) BO ₃ : Eu and BaMgAl ₁₀ O ₁₇ : Eu were prepared in red and blue discharge cells, respectively.

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 1

A plasma display panel was manufactured in the same manner as in Example 1, except that a green phosphor layer having a thickness of 20 μm was formed using only a green phosphor, Zn ₂ SiO ₄ : Mn.

Comparative Example 2

A plasma display panel was manufactured in the same manner as in Example 1, except that a green phosphor layer having a thickness of 20 μm was formed by uniformly mixing the green phosphor Zn ₂ SiO ₄ : Mn and YBO ₃ : Tb in a weight ratio of 1: 1. Prepared.

[Examples 2 to 4 and Comparative Examples 3 to 6]

A plasma display panel was manufactured in the same manner as in Example 1, except that the green phosphor was formed by mixing Zn ₂ SiO ₄ : Mn and YBO ₃ : Tb with the composition shown in Table 1 below.

Mixing ratio (MAO: Y) Example 2 60:40 Example 3 50:50 Example 4 40:60 Comparative Example 3 100: 0 Comparative Example 4 90:10 Comparative Example 5 80:20 Comparative Example 6 30:70 Comparative Example 7 0: 100

After lighting only the green phosphor layers of the plasma display panels of Examples 1 to 4 and Comparative Examples 1 to 7, the luminance and color coordinates of the green light emitted from the PDP were measured using a contact luminance meter (CA-100). In addition, the permanent afterimage was measured by the change in the color temperature, and after accelerating aging by making a specific pattern for a specific time, the color temperature and luminance difference between the display unit and the non-display unit were measured. In general, when the color temperature is about 9000K, the luminance difference is 5 cd / m ² or more and the color temperature difference is 300K or more, and a permanent afterimage is observed.

The measurement results of the luminance, color coordinates, and permanent persistence appearance time are shown in Table 2 below.

Luminance Color coordinates Permanent afterimage appearance time Example 1 105% (0.245, 0.070) 80hr Example 2 106% (0.260, 0.069) 90hr Example 3 107% (0.270, 0.068) 100hr Example 4 107.5% (0.280, 0.065) 100hr Comparative Example 1 100% (0.245, 0.700) 6hr Comparative Example 2 110% (0.285, 0.65) 10hr Comparative Example 3 100% (0.19, 0.75) 50hr Comparative Example 4 102% (0.205, 0.735) 60hr Comparative Example 5 104% (0.23, 0.71) 70hr Comparative Example 6 108% (0.30, 0.63) 100hr Comparative Example 7 110% (0.312, 0.611) 100hr

As shown in Table 2, the brightness of Examples 1 to 4 of the present invention was similar to the comparative example including the Zn-based phosphor, the permanent afterimage and color reproducibility was much better than the comparative example. In particular, in the case of permanent afterimage, Examples 1 to 4 of the present invention were improved by at least 8 times compared to Comparative Examples 1 or 2.

In addition, with respect to the discharge characteristics, Comparative Example 1 containing only Zn ₂ SiO ₄ : Mn as a result of measuring the surface charge amount of the phosphor by using a powder charge measuring device TB-200 of Toshiba Chemical Co. In the case of (-), the green phosphor of Example 1 of the present invention was confirmed that the charge amount is (+), which has better discharge characteristics.

The plasma display panel of the present invention includes a green phosphor composition or a phosphor layer including MAO-based phosphors and Y-based phosphors in an optimal mixing ratio, thereby not only maintaining excellent luminance but also improving color reproduction and permanent image retention.

Claims (8)

Green phosphor composition for a plasma display panel comprising a magnesium aluminum oxide (MAO) series phosphor and yttrium (Y) series phosphor. The green phosphor composition of claim 1, wherein the magnesium aluminum oxide-based phosphor is at least one phosphor selected from the group consisting of MgAl _x O _y : Mn (1 ≦ _x ≦ 10, 1 ≦ _y ≦ 30). . The green phosphor composition of claim 1, wherein the yttrium-based phosphor is at least one phosphor selected from the group consisting of YBO ₃ : Tb and (Y, Gd) BO ₃ : Tb. The green phosphor composition of claim 1, wherein a mixing ratio of the magnesium aluminum oxide phosphor and the yttrium phosphor is 70:30 to 40:60. A first substrate and a second substrate disposed to face each other; A plurality of display electrodes provided on the first substrate, the address electrodes provided on the first substrate, and a pair of scan electrodes and sustain electrodes; 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; And A red, green, and blue phosphor layer formed in the discharge cell partitioned by the partition wall; The green phosphor layer is formed by applying a green phosphor composition comprising a magnesium aluminum oxide-based phosphor and yttrium-based phosphor. The plasma display panel of claim 5, wherein the magnesium aluminum oxide-based phosphor is at least one phosphor selected from the group consisting of MgAl _x O _y : Mn (1 ≦ _x ≦ 10, 1 ≦ _y ≦ 30). The plasma display panel of claim 5, wherein the yttrium-based phosphor is at least one phosphor selected from the group consisting of YBO ₃ : Tb and (Y, Gd) BO ₃ : Tb. The plasma display panel of claim 5, wherein a mixing ratio of the magnesium aluminum oxide phosphor and the yttrium phosphor is 70:30 to 40:60.

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