KR20110024580A - Plasma display apparatus - Google Patents

Abstract

PURPOSE: A plasma display apparatus is provided to improve the luminance by additionally securing the light emission area within the discharge space. CONSTITUTION: A partition wall(326) is formed on a lower substrate opposed to the top substrate. A partition wall divides the discharge space. The fluorescent material layer(329) is formed on the bottom surface and the side of the discharge space. The fluorescent material layer is made of the phosphor paste.

Description

Plasma display apparatus

The present invention relates to a plasma display device, and more particularly, to a plasma display device in which a thickness of a phosphor layer formed on a side of a discharge space is thicker than a thickness of a phosphor layer formed on a bottom surface of a discharge space.

In general, a plasma display panel is a partition wall formed between an upper substrate and a lower substrate to form one unit cell, and each cell includes neon (Ne), helium (He), or a mixture of neon and helium (Ne + He) and An inert gas containing the same main discharge gas and a small amount of xenon is filled.

When discharged by a high frequency voltage, the inert gas generates vacuum ultraviolet rays and emits phosphors formed between the partition walls to realize an image. Such a plasma display panel has a spotlight as a next generation display device because a thin and light configuration is possible.

On the other hand, the phosphor layer may be formed by filling the paste between the partition walls and drying. However, the solvent contained in the existing paste has a low vapor pressure, so that the drying speed of the phosphor paste is lowered, and thus the phosphor layer is mainly formed on the bottom of the discharge space, and it is difficult to form the phosphor layer with a sufficient thickness on the side of the partition wall. As a result, light emission dominates at the bottom of the discharge space. The light emitted from the bottom part has a problem that the loss of light intensity is large due to the diffuse reflection, and thus the luminance of the plasma display panel may be lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma display device which can improve luminance by additionally securing a light emitting area in a discharge space.

Plasma display device of the present invention for solving the above object comprises an upper substrate, a partition formed on the lower substrate facing the upper substrate to partition the discharge space and the phosphor layer formed on the bottom and side of the discharge space, the discharge The thickness of the phosphor layer formed on the side of the discharge space is thicker than the thickness of the phosphor layer formed on the bottom of the space.

In the present invention, the ratio of the thickness of the phosphor layer formed on the bottom of the discharge space to the thickness of the phosphor layer formed on the side of the discharge space is 1: 1.43 to 1: 1.82.

In the plasma display device according to the present invention, the thickness of the phosphor layer formed on the side of the discharge space is made thicker than the thickness of the phosphor layer formed on the bottom surface of the discharge space, whereby the light emitting area in the discharge space is added to the luminance of the plasma display device. Increases.

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

1 is a perspective view illustrating an embodiment of a plasma display device.

As shown in FIG. 1, the plasma display apparatus includes a scan electrode 11, a sustain electrode 12, and an address electrode 22 formed on the lower substrate 20, which are pairs of sustain electrodes formed on the upper substrate 10. It includes.

The sustain electrode pairs 11 and 12 generally include transparent electrodes 11a and 12a and bus electrodes 11b and 12b formed of indium tin oxide (ITO), and the bus electrodes 11b and 12b. 12b) may be formed of a metal such as silver (Ag) or chromium (Cr) or a stack of chromium / copper / chromium (Cr / Cu / Cr) or a stack of chromium / aluminum / chromium (Cr / Al / Cr). . The bus electrodes 11b and 12b are formed on the transparent electrodes 11a and 12a to serve to reduce voltage drop caused by the transparent electrodes 11a and 12a having high resistance.

Meanwhile, according to the exemplary embodiment of the present invention, the sustain electrode pairs 11 and 12 may not only have a structure in which the transparent electrodes 11a 12a and the bus electrodes 11b and 12b are stacked, but also the buses without the transparent electrodes 11a and 12a. Only the electrodes 11b and 12b may be configured. This structure does not use the transparent electrodes (11a, 12a), there is an advantage that can lower the cost of manufacturing the panel. The bus electrodes 11b and 12b used in this structure can be various materials such as photosensitive materials in addition to the materials listed above.

Between the transparent electrodes 11a and 12a of the scan electrode 11 and the sustain electrode 12 and the bus electrodes 11b and 12b, external light generated outside the upper substrate 10 is absorbed to reduce reflection. First black matrices BM, 11c, and 12c may be arranged to serve to block light and to improve purity and contrast of the upper substrate 10.

Meanwhile, the second black matrix 15 is formed on the upper substrate 10, and may be formed at a position overlapping the partition wall 21. Here, the second black matrix 15 and the first black matrices 11c and 12c, also referred to as black layers or black electrode layers, may be simultaneously formed and physically connected in the formation process, or may not be simultaneously formed and thus not physically connected. .

In addition, when physically connected and formed, the second black matrix 15 and the first black matrices 11c and 12c may be formed of the same material, but may be formed of different materials when they are physically separated.

The upper dielectric layer 13 and the passivation layer 14 are stacked on the upper substrate 10 having the scan electrode 11 and the sustain electrode 12 side by side. Charged particles generated by the discharge are accumulated in the upper dielectric layer 13, and the protective electrode pairs 11 and 12 may be protected. The protective film 14 protects the upper dielectric layer 13 from sputtering of charged particles generated during gas discharge, and increases emission efficiency of secondary electrons.

In addition, the address electrode 22 is formed in a direction crossing the scan electrode 11 and the sustain electrode 12. In addition, a lower dielectric layer 24 and a partition wall 21 are formed on the lower substrate 20 on which the address electrode 22 is formed.

In addition, the phosphor layer 23 is formed on the surfaces of the lower dielectric layer 24 and the partition wall 21. The phosphor layer 23 may be formed to have a thickness greater than that of the dielectric layer 24 to be applied to the surface of the partition wall 21, thereby improving brightness of the plasma display panel. This will be described later with reference to FIG. 4.

The partition wall 21 has a vertical partition wall 21a and a horizontal partition wall 21b formed in a closed shape, and physically distinguishes discharge cells, and prevents ultraviolet rays and visible light generated by the discharge from leaking into adjacent discharge cells.

Meanwhile, the partition wall 21 may not only have a structure of the partition wall 21 shown in FIG. 1 but also a structure of the partition wall 21 having various shapes. For example, a channel in which a channel usable as an exhaust passage is formed in at least one of the differential partition structure, the vertical partition 21a, or the horizontal partition 21b having different heights of the vertical partition 21a and the horizontal partition 21b. A grooved partition structure in which a groove is formed in at least one of the type partition wall structure, the vertical partition wall 21a, or the horizontal partition wall 21b is also possible.

Here, in the case of the differential partition wall structure, the height of the horizontal partition wall 21b is more preferable, and in the case of the channel partition wall structure or the groove partition wall structure, it is preferable that a channel is formed or the groove is formed in the horizontal partition wall 21b. Do.

Meanwhile, in one embodiment of the present invention, although the R, G and B discharge cells are shown and described as being arranged on the same line, it may be arranged in other shapes. For example, a Delta type arrangement in which R, G, and B discharge cells are arranged in a triangular shape may be possible. In addition, the shape of the discharge cell is not only rectangular, but also various polygonal shapes such as pentagon and hexagon.

In addition, the phosphor layer 23 is emitted by ultraviolet rays generated during gas discharge to generate visible light of any one of red (R), green (G), and blue (B). Here, an inert mixed gas such as He + Xe, Ne + Xe and He + Ne + Xe for discharging is injected into the discharge space provided between the upper / lower substrates 10 and 20 and the partition wall 21.

FIG. 2 illustrates an embodiment of an electrode arrangement of a plasma display panel, and the plurality of discharge cells 30 constituting the plasma display panel is preferably arranged in a matrix form as shown in FIG. 2. The plurality of discharge cells 30 are provided at the intersections of the scan electrode lines Y1 to Ym, the sustain electrode lines Z1 to Zm, and the address electrode lines X1 to Xn, respectively. The scan electrode lines Y1 to Ym may be driven sequentially or simultaneously, and the sustain electrode lines Z1 to Zm may be driven simultaneously. The address electrode lines X1 to Xn may be driven by being divided into odd-numbered lines and even-numbered lines, or sequentially driven.

Since the electrode arrangement shown in FIG. 2 is only an embodiment of the electrode arrangement of the plasma panel according to the present invention, the present invention is not limited to the electrode arrangement and driving method of the plasma display panel shown in FIG. 2. For example, a dual scan method in which two scan electrode lines among the scan electrode lines Y1 to Ym are simultaneously scanned is possible. In addition, the address electrode lines X1 to Xn may be driven by being divided up and down in the center portion of the panel.

3A to 3C are diagrams schematically illustrating a process of forming a phosphor layer by phosphor screen printing.

Screen printing, photosensitive paste, dry film and the like are applied to the method of applying the phosphor, but in consideration of the simplicity and cost of the process, screen printing is widely used.

Referring to FIGS. 3A through 3C, a process of forming a phosphor by screen printing is described below. First, a barrier rib (on a lower substrate 320 on which an address electrode 322, a lower dielectric layer 324, and a barrier rib 326 are sequentially formed) may be used. Position the screen mask 335 with openings selectively formed in correspondence with the space between 326. Subsequently, the phosphor paste 328 is filled in the space between the partition walls 326 using the squeeze rubber 330.

The screen mask 335 and the phosphor 328 are replaced, and the above-described process is repeated, and the screen mask 335 is removed after filling the R, G, and B phosphor pastes 328, respectively.

Subsequently, when the lower panel 320 of the plasma display panel is dried, the organic solvent included in the phosphor paste 328 evaporates and the volume is reduced, as shown in FIG. 3C, and thus the phosphor layer 329 is formed on the surfaces of the lower dielectric layer 324 and the partition wall 326. Will be formed.

According to the present invention, the phosphor paste 328 for forming the phosphor layer 329 is formed using a solvent having a high vapor pressure. Accordingly, the drying speed of the phosphor paste 328 is improved, so that the phosphor layer 329 can be formed to a sufficient thickness on the side surface of the partition wall 326, so that the thickness and the discharge space of the phosphor layer 329 formed at the bottom of the discharge space. The thickness ratio of the phosphor layer 329 formed on the side may be 1: 1.43 to 1: 1.82. This will be described later in detail with reference to FIG. 4.

The phosphor paste 328 may include a phosphor powder, a binder, a magnesium oxide (MgO) powder, and a solvent.

The phosphor powder may be any one of red, green and blue phosphor powders, and in red, Y ₂ O ₃ : Eu, YVO ₄ : Eu, (Y, Gd) BO ₃ : Eu, Y ₂ O ₃ S: Eu, γ-Zn ₃ (PO ₄ ) ₂ : Mn, (Zn, Cd) S: Ag + In ₂ O ₃ , Y (P, V) O ₄ : Eu and the like.

In addition, in green, Zn ₂ GeO ₂ : Mn, BaAl ₁₂ O ₁₉ : Mn, Zn ₂ SiO ₄ : Mn, LaPO ₄ : Tb, ZnS: Cu, Al, ZnS: Au, Cu, Al, (Zn, Cd) S: Cu, Al, Zn ₂ SiO ₄ : Mn, As, Y ₃ Al ₅ O ₁₂ : Ce, CeMgAl ₁₁ O ₁₉ : Tb, Gd ₂ O ₂ S: Tb, Y ₃ Al ₅ O ₁₂ : Tb, ZnO: Zn, (Y, Gd) BO ₃ : Tb, (Ba, Sr, Mg) O.aAl ₂ O ₃ Mn, and the like, and Sr ₅ (PO ₄ ) ₃ Cl: Eu, BaMgAl ₁₄ O _{23 as} blue. : Eu, BaMgAl ₁₆ O ₂₇ : Eu, BaMg ₂ Al ₁₄ O ₂₄ : Eu, CaMgSi ₂ O ₆ : Eu, Y ₂ SiO ₃ : Ce, BaMgAl ₁₀ O ₁₇ : Eu, and the like.

It is preferable that the particle diameter of such fluorescent substance powder is 0.2-5 micrometers. When the particle size of the phosphor powder is smaller than 0.2 µm, the aggregation of the phosphor powder is likely to occur, and the surface is activated, and thus, chemical reaction with other components such as a binder can be caused. On the other hand, when the particle diameter is larger than 5 μm, the phosphor layer 329 may become nonuniform or, therefore, uneven in brightness, which is not preferable.

On the other hand, if the amount of the phosphor powder is less than 30wt%, the coating thickness of the paste 328 necessary to obtain the desired phosphor layer 329 thickness becomes thick, so that color mixing may occur between adjacent discharge cells, whereas inclusion of the phosphor powder If the amount exceeds 50wt%, the viscosity of the phosphor paste 328 may be increased, thereby decreasing dispensing coating uniformity. Therefore, the phosphor powder is preferably contained in 30 to 50wt%.

The binder functions as a binder of each component, and cellulose-based resins such as ethyl cellulose, methyl cellulose, nitrocellulose, cellulose acetate, cellulose propionate, cellulose butyrate, hydroxy cellulose, and methyl hydroxy cellulose may be used. have.

In addition, the content of the binder is preferably 5 to 10wt%. This is because when the amount of the binder is less than 5wt%, the bonding force of the phosphor layer 329 may be lowered, and when the amount of the binder is greater than 10wt%, the phosphor content in the phosphor layer 329 may be relatively reduced, resulting in deterioration of characteristics such as color purity. .

Magnesium oxide (MgO) powder is added to increase the secondary electron emission coefficient to reduce discharge voltage and prevent hot discharge. This is due to the electrical properties of the oxide material, before the discharge occurs in the portion where the phosphor powder is disposed, the discharge occurs first in the portion where the magnesium oxide powder is disposed at a relatively low voltage, and the discharge is spread to the portion where the phosphor powder is placed. Because it becomes.

The magnesium oxide powder is preferably added at 1 to 10wt%. When the amount of magnesium oxide powder added is less than 1wt%, the effect of adding magnesium oxide is insignificant, and when it is added in excess of 10wt%, the ratio of the supplementary magnesium oxide of the phosphor increases, so that the overall brightness may be reduced.

The solvent is preferably included in the phosphor paste in the total amount of 30 to 60wt%, but may include butylene carbonate (Butylene Carbonate, BC), butyl carbitol acetate (BCA). If the solvent content is less than 30wt%, the phosphor may not be dispersed properly, or the viscosity of the phosphor paste may be too high, resulting in uneven phosphor coating thickness. On the other hand, when the content of the solvent is greater than 60wt%, the content of the phosphor per unit volume is too low, which is not preferable because the luminance is lowered.

In particular, the phosphor paste 328 according to the present invention, N-methylpyrrolidone (NMP) having a vapor pressure of 0.04 kPa or more at 20 ° C. to improve the drying speed of the phosphor paste 328, terpinol ( At least one of solvents such as Terpinol) and an amide series may be mixed and used.

In this way, by mixing and using a solvent having a high vapor pressure, the drying speed of the phosphor paste 328 can be improved, and the phosphor layer 329 can be formed with a sufficient thickness on the side surface of the partition wall 326.

On the other hand, N-methylpyrrolidone (N-methylpyrrolidone, NMP), terpinol (Terpinol), it is preferable that a solvent such as amide (Amide) series is contained in 10 to 30wt%. If it is less than 10wt%, the thickness of the phosphor layer 329 formed on the side of the partition may not be sufficient. On the other hand, if it is greater than 30wt%, the volatility may be so high that it may be difficult to manufacture and apply the phosphor paste 328. Because there is.

Further, to the phosphor paste, photosensitive components such as photosensitive monomers, photosensitive oligomers, and photosensitive polymers, and additive components of at least one of photopolymerization initiators, sensitizers, antioxidants, ultraviolet absorbers and polymerization inhibitors can be added.

Table 1 below is a result of comparing the thickness ratio of the bottom and side surfaces of the phosphor layer formed of a phosphor paste using a mixture of a conventional phosphor paste and a solvent having a high vapor pressure according to the present invention, and FIG. It is a figure which shows the result of the comparative example 1 and Example 2. FIG.

In Table 1, the drying ratio means a ratio of the thicknesses a1 and a2 of the phosphor layer formed on the bottom of the discharge space and the thicknesses b1 and b2 of the phosphor layer formed on the side of the discharge space. In addition, the thickness (a1, a2) of the phosphor layer formed on the bottom of the discharge space is the thickness of the bottom center, the thickness (b1, b2) of the phosphor layer formed on the side of the discharge space means the thickness of the thickest phosphor layer in the side wall portion. do. In addition, all the units of the added component are wt% unless there is particular notice.

In Table 1, in the case of Comparative Example 1, only the conventional solvent was used, and Examples 1, 2, and 2 were N-methylpyrrolidone (NMP) having a vapor pressure of 0.04 kPa or more at 20 ° C. This is the case when mixed.

Referring to Table 1, compared with Comparative Example 1, Example 1 and Example 2 has a drying ratio of 1.43 to 1.82, as a result it can be seen that the brightness increased by at least 5%.

Referring to FIG. 4, which shows Comparative Examples 1 and 2, the thickness b2 of the phosphor layer formed on the side surface of the partition wall of FIG. 4B is thicker than that of FIG. 4A. It can be seen that the phosphor layer is formed to the upper end of the partition wall, thereby securing an additional light emitting area A. This is a result of increasing the vapor pressure of the solvent contained in the phosphor paste to increase the drying rate of the phosphor paste so that the phosphor paste can be formed to a sufficient thickness without flowing down the side of the partition wall.

On the other hand, in the phosphor paste, the solvent evaporates in the drying step, and only the inorganic component forms the phosphor layer. Since the inorganic component contains a certain amount, when the thickness of the phosphor layer formed on the side surface of the partition is improved, the thickness of the phosphor layer formed on the bottom of the discharge space is relatively thin.

That is, the thickness a2 of the phosphor layer formed on the bottom of the discharge space of FIG. 4B is thinner than the thickness a1 of the phosphor layer formed on the bottom of the discharge space of FIG.

As a result, Example 1 and Example 2 compared with Comparative Example 1 to prevent the loss of the brightness of the light due to the reflection of the diffuse reflection occurs when the light emission dominates at the bottom of the discharge space, and to secure the additional light emitting area (A) Therefore, the brightness is improved.

However, in Comparative Example 2, N-methylpyrrolidone (NMP) was used in the same manner as in Example 1 and Example 2, but the drying ratio was 2.01. In addition, when the thickness of the phosphor layer formed on the side surface of the partition wall is too thick, light generated in the plasma display panel may be blocked to decrease the aperture ratio.

Therefore, the ratio of the thickness a2 of the phosphor layer formed on the bottom of the discharge space and the thickness b2 of the phosphor layer formed on the side of the discharge space is preferably 1: 1.43 to 1: 1.82. At this time, a sufficient discharge space can be secured and the light brightness can be improved. At this time, the thickness (b2) of the phosphor layer formed on the side of the discharge space may be formed to 5 to 11㎛. Similarly, since the thickness b2 of the phosphor layer formed on the side of the discharge space is 5 to 11 占 퐉, the discharge space and the aperture ratio can be sufficiently secured, and the optical brightness of the plasma display panel can be improved.

As such, the ratio of the thickness a2 of the phosphor layer formed on the bottom of the discharge space to the thickness b2 of the phosphor layer formed on the side of the discharge space is 1: 1.43 to 1: 1.82 to increase the drying speed of the phosphor paste. It is necessary to make, the phosphor paste according to the present invention may include a solvent such as N-methylpyrrolidone (N-methylpyrrolidone, NMP), Terpinol (Terpinol), amide (Amide) series such as 10 to 30wt% have.

While the preferred embodiments of the present invention have been shown and described, the present invention is not limited to the specific embodiments described above, and the present invention is not limited to the specific embodiments of the present invention, without departing from the spirit of the invention as claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a perspective view illustrating an embodiment of a plasma display device.

2 illustrates an embodiment of an electrode arrangement of a plasma display panel.

3A to 3C are diagrams illustrating a process of forming a phosphor layer.

4 is a diagram illustrating a conventional phosphor layer and a phosphor layer according to an embodiment of the present invention.

Claims (10)

Upper substrate; Barrier ribs formed on a lower substrate facing the upper substrate to partition a discharge space; And It includes a phosphor layer formed on the bottom and side surfaces of the discharge space, And a thickness of the phosphor layer formed on a side surface of the discharge space is thicker than a thickness of the phosphor layer formed on the bottom of the discharge space. The method of claim 1, And a ratio of the thickness of the phosphor layer formed on the bottom of the discharge space and the thickness of the phosphor layer formed on the side of the discharge space is 1: 1.43 to 1: 1.82. The method of claim 1, The thickness of the phosphor layer formed on the side of the discharge space is 5 to 11㎛ plasma display device. The method of claim 1, The thickness of the phosphor layer formed on the side of the discharge space is the plasma display device thickest in the phosphor layer. The method of claim 1, And a thickness of the phosphor layer formed on a bottom surface of the discharge space is a thickness of a center of the discharge space. The method of claim 1, The phosphor layer is formed of a phosphor paste, wherein the phosphor paste includes 30 to 50 wt% of phosphor powder, 1 to 10 wt% of magnesium oxide (MgO) powder, 5 to 10 wt% of a binder, and 30 to 60 wt% of a solvent. Plasma display device. The method of claim 6, The solvent includes at least one of N-methylpyrrolidone (N-methylpyrrolidone, NMP), terpinol (Terpinol) and amide (Amide) -based solvent. The method of claim 7, wherein At least one of the N-methylpyrrolidone (N-methylpyrrolidone, NMP), Terpinol and amide (Amide) -based solvent is 10 to 30wt% plasma display device. The method of claim 6, Particle diameter of the phosphor powder is 0.2 to 5㎛ plasma display device. The method of claim 6, The phosphor paste further includes at least one of a photopolymerization initiator, a sensitizer, an antioxidant, an ultraviolet absorber, and a polymerization inhibitor.

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