KR20070077317A - Plasma display panel - Google Patents

Abstract

A plasma display panel is provided to increase the emitted amount of secondary electrons and to reduce a discharge time by forming a magnesium oxide protective layer including zirconium. A pair of substrates(110,120) are disposed opposite to each other. A plurality of barrier ribs(130) are positioned between the pair of the substrates in order to form discharge cells. A plurality of discharge electrodes(112) are arranged between the pair of substrates. A dielectric layer(114,122) is formed to cover the discharge electrodes. A protective layer(115) including MgO and Zr is formed to cover at least a part of the dielectric layer. A phosphor layer(140) is formed within each of the discharge cells. The discharge cells are filled with discharge gas.

Description

 Plasma display panel {Plasma display panel}

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

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

3 is an enlarged cross-sectional view of a portion of the protective layer of FIG. 2.

4 is a comparison graph of secondary electron emission coefficients according to Examples 1 and 2, Comparative Example 1, Comparative Example 3, and Comparative Example 6. FIG.

5 is a comparative graph of discharge delay times according to Examples 1, 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5 and Comparative Example 6. FIG.

6 is a comparison graph of secondary electron emission coefficients according to Examples 3 and 7;

Explanation of symbols on the main parts of the drawings

100: plasma display panel 110: front substrate

111: first discharge electrode 112: second discharge electrode

113: bus electrode 114: first dielectric layer

115: protective layer 120: back substrate

121: address electrode 122: second dielectric layer

130: partition 140: phosphor layer

150: discharge cell

The present invention relates to a plasma display panel, and more particularly, to a plasma display panel having a protective layer containing zirconium (Zr).

Plasma Display Panel (PDP) is a flat panel display device that displays an image using a gas discharge phenomenon, and has been in the spotlight recently because it is possible to realize a thin screen and a high quality large screen having a wide viewing angle.

In general, the plasma display panel includes a discharge electrode positioned between two substrates disposed to face each other, a dielectric layer covering the discharge electrode, a protective layer covering the dielectric layer, and the like.

The protective layer serves to protect the dielectric layer and emit secondary electrons. The protective layer of a conventional plasma display panel is mainly composed of magnesium oxide (MgO).

However, in manufacturing such a conventional protective layer, it is difficult to emit secondary electrons enough to sufficiently lower the driving voltage by not considering the content and properties of impurities other than magnesium oxide, and discharge delay. There was a problem that the time is long. Accordingly, there is a need to develop a plasma display panel having a protective layer having a new structure capable of sufficiently emitting secondary electrons and shortening a discharge delay time.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems as described above, and its main object is to provide a plasma display panel having a protective layer containing zirconium.

The present invention provides a pair of substrates spaced apart from each other at a predetermined interval and facing each other, a partition wall disposed between the pair of substrates and defining a discharge cell together with the pair of substrates, and the pair of substrates. Discharge electrodes disposed on the substrate, a dielectric layer formed to cover the discharge electrodes, a protective layer formed to cover at least a portion of the dielectric layer and including magnesium oxide (MgO) and zirconium (Zr), and in the discharge cell. A plasma display panel including a phosphor layer disposed and a discharge gas in the discharge cell is provided.

Here, the content of the zirconium is preferably 65 to 80ppm based on the content of the magnesium oxide (MgO).

Here, the content of the zirconium is preferably increased on average as the depth deeper from the surface direction of the protective layer toward the dielectric layer.

Here, it is preferable that a part of the portion of the protective layer has a content of less than or equal to that of the zirconium than the other part which is relatively closer to the dielectric layer than the part.

The protective layer may be formed by one process selected from the group consisting of a chemical vapor deposition (CVD) process, an E-beam process, an ion plating process, and a sputtering process. Can be prepared.

Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings.

1 is a schematic exploded perspective view of a plasma display panel according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, and FIG. 3 is an enlarged view of the protective layer of FIG. 2. One cross section.

1 and 2, the plasma display panel 100 according to the exemplary embodiment of the present invention is disposed in parallel with the transparent first substrate 110 and spaced apart at predetermined intervals from the first substrate 110. The second substrate 120 is provided.

In the present embodiment, since the first substrate 110 is transparent, visible light generated by the discharge passes through the first substrate 110, but the present invention is not limited thereto. That is, while the first substrate of the present invention is opaque, the second substrate may be configured to be transparent, and the first substrate and the second substrate may be configured to be transparent at the same time. In addition, the first substrate and the second substrate of the present invention may be made of a semi-transparent material, it may be configured by embedding a color filter on the surface or inside.

On the first substrate 110, stripe-shaped first discharge electrodes 111, second discharge electrodes 112, and bus electrodes 113 are formed.

One of the first discharge electrode 111 and the second discharge electrode 112 functions as a scan electrode and the other function as a common electrode, and is usually made of a transparent electrode made of indium tin oxide (ITO). have.

The bus electrode 113 is installed on the lower surfaces of the first discharge electrode 111 and the second discharge electrode 112, and is formed of a metal material and formed in a narrow width to reduce line resistance.

The first dielectric layer 114 is formed on the first discharge electrode 111, the second discharge electrode 112, and the bus electrode 113.

The first dielectric layer 114 prevents the first discharge electrode 111 and the second discharge electrode 112 from being directly energized during the sustain discharge, and charged particles are discharged from the first discharge electrode 111 and the second discharge electrode 112. ), And to prevent charged particles from being damaged, and to induce charged particles to accumulate wall charges. PbO, B ₂ O ₃ , SiO _2, and the like are used as such dielectrics.

A protective layer 115 is formed on the surface of the first dielectric layer 114. The protective layer 115 is damaged by the first discharge electrode 111 and the second discharge electrode 112 by sputtering of plasma particles. It serves to reduce the discharge voltage by emitting secondary electrons.

The address electrode 121 is formed on the second substrate 120.

The address electrode 121 performs an address discharge together with a discharge electrode serving as a scan electrode among the first discharge electrode 111 and the second discharge electrode 112.

The second dielectric layer 122 is formed on the address electrode 121, and the second dielectric layer 122 is formed of the same material as the first dielectric layer 114, and serves to protect the address electrode 121.

Meanwhile, in the present exemplary embodiment, the first discharge electrode 111 and the second discharge electrode 112 are disposed in parallel on the first substrate 110, and the address electrode 121 is disposed on the second substrate 120. In the case of the plasma display panel of the present invention, the first discharge electrode 111 and the second discharge electrode 112 can be driven without the address electrode 121. In this case, the first discharge electrode and the second discharge can be driven. The electrodes are arranged to cross so that one of them simultaneously performs the addressing action.

A partition wall 130 is formed on the second dielectric layer 122. The partition wall 130 maintains a discharge distance and prevents electro-optic crosstalk between discharge cells.

The partition 130 forms a discharge space together with the first discharge electrode 111, the second discharge electrode 112, and the address electrode 121, which are called discharge cells 150, and the discharge cells 150 are Each form a sub-pixel.

In addition, as shown in FIG. 1, in the embodiment of the present invention, the cross section of the discharge cell 150 defined by the partition wall 130 is illustrated as being rectangular, but the present invention is not limited thereto. It may also be formed in a polygonal form, such as a circle, an ellipse, or the like, and the partition wall may be formed in a stripe pattern to form an open partition wall.

On the other hand, red, green, and blue phosphors are coated on the upper surface of the second dielectric layer 122 and the sidewalls of the partition 130 forming the lower surface of the discharge cell to form the phosphor layer 140.

The phosphor layers 140 have a component for generating visible light by receiving ultraviolet rays. The red phosphor layer formed in the red light emitting cell includes phosphors such as Y (V, P) O ₄ : Eu, and the green light emitting cell The green phosphor layer formed at includes a phosphor such as Zn ₂ SiO ₄ : Mn, and the blue phosphor layer formed at the blue light emitting discharge cell includes a phosphor such as BAM: Eu.

After the first substrate 110 and the second substrate 120 are sealed, the space inside the assembled plasma display panel 100 is filled with air, thereby completely removing the air in the assembled plasma display panel 100. By exhausting, air is replaced with an appropriate discharge gas capable of increasing the efficiency of discharge. As the discharge gas, a mixed gas such as Ne-Xe, He-Xe, He-Ne-Xe is often used.

An exemplary discharge process of the plasma display panel 100 according to an exemplary embodiment of the present invention configured as described above will be described below.

First, when a predetermined address voltage is applied between the discharge electrode serving as the scan electrode of the first discharge electrode 111 and the second discharge electrode 112 and the address electrode 121 from an external power source, an address discharge is generated. A discharge cell in which sustain discharge occurs as a result of this address discharge is selected.

Thereafter, when a discharge sustain voltage is applied between the first discharge electrode 111 and the second discharge electrode 112 of the selected discharge cell, the first discharge electrode 111 and the first discharge electrode 111 of the portion of the first dielectric layer 114 are applied. The maintenance discharge is caused by the movement of the wall charges accumulated near the two discharge electrodes 112. In this case, the protective layer 115 protects the first dielectric layer 114 and performs a function of emitting secondary electrons.

When the above sustain discharge occurs, the discharge gas is excited, and the excited discharge gas emits ultraviolet rays while the energy level is lowered.

The ultraviolet rays excite the phosphor of the phosphor layer 140 coated in the discharge cell, and the visible light is emitted as the energy level of the excited phosphor is lowered, and the emitted visible light is projected onto the first substrate 110. As it exits, it forms an image that the user can recognize.

As described above, the protective layer 115 of the plasma display panel 100 functions to protect the first dielectric layer 114 and to discharge secondary electrons to help discharge. Hereinafter, the configuration of the protective layer 115 will be described in detail. Let's look at it.

The protective layer 115 includes magnesium oxide (MgO) as a main component and includes zirconium (Zr).

Processes used in the manufacture of the protective layer 115 include, but are not limited to, chemical vapor deposition (CVD), E-beam, Ion-plating, and sputtering ( It may be deposited by a sputtering process or the like.

Zirconium (Zr) included in the protective layer 115 is used in an amount of 65 to 80 ppm based on the content of magnesium oxide. This is because if the content of zirconium (Zr) is less than 65ppm or more than 80ppm, the secondary electron emission coefficient is lowered, thereby reducing the secondary electron emission amount and increasing the discharge delay time.

Secondary electron emission characteristics and discharge delay time characteristics according to the content of zirconium (Zr) can be confirmed by the experimental results of the following Examples 1, 2, Comparative Example 1, Comparative Example 2, Comparative Example 3. .

Example 1

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, 65 ppm of zirconium (Zr) was added to magnesium oxide (MgO) to prepare pellets, and then the pellets were heat-treated at 350 ° C. and deposited by ion plating to prepare a protective layer on the dielectric layer. The secondary electron emission coefficient and discharge delay time were measured in the plasma environment measurement chamber using the substrate.

Example 2

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, 80 ppm of zirconium (Zr) was added to magnesium oxide (MgO) to prepare pellets, and then the pellets were heat-treated at 350 ° C. and deposited by ion plating to prepare a protective layer on the dielectric layer. The secondary electron emission coefficient and discharge delay time were measured in the plasma environment measurement chamber using the substrate.

Comparative Example 1

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, pellets were prepared of magnesium oxide (MgO), and then the pellets were heat-treated at 350 ° C. and deposited by ion plating to prepare a protective layer on the dielectric layer. The secondary electron emission coefficient and discharge delay time were measured in the plasma environment measurement chamber using the substrate.

Comparative Example 2

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, 20 ppm of zirconium (Zr) was added to magnesium oxide (MgO) to prepare pellets, and then the pellets were heat-treated at 350 ° C. and deposited by ion plating to prepare a protective layer on the dielectric layer. The discharge delay time was measured in the plasma environment measurement chamber with the substrate.

Comparative Example 3

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 120 μm. Thereafter, 40 ppm of zirconium (Zr) was added to magnesium oxide (MgO) to prepare pellets, and then the pellets were heat-treated at 350 ° C. and deposited by ion plating to prepare a protective layer on the dielectric layer. The secondary electron emission coefficient and discharge delay time were measured in the plasma environment measurement chamber using the substrate.

Comparative Example 4

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, 50 ppm of zirconium (Zr) was added to magnesium oxide (MgO) to prepare pellets, and then the pellets were heat treated at 350 ° C. and deposited by ion plating to prepare a protective layer on the dielectric layer. The discharge delay time was measured in the plasma environment measurement chamber with the substrate.

Comparative Example 5

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, 100 ppm of zirconium (Zr) was added to magnesium oxide (MgO) to prepare pellets, and then the pellets were heat-treated at 350 ° C. and deposited by ion plating to prepare a protective layer on the dielectric layer. The discharge delay time was measured in the plasma environment measurement chamber with the substrate.

Comparative Example 6

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, 120 ppm of zirconium (Zr) was added to magnesium oxide (MgO) to prepare pellets, and then the pellets were heat-treated at 350 ° C. and deposited by ion plating to prepare a protective layer on the dielectric layer. The secondary electron emission coefficient and discharge delay time were measured in the plasma environment measurement chamber using the substrate.

4 is a comparison graph of secondary electron emission coefficients according to Examples 1, 2, Comparative Example 1, Comparative Example 3, and Comparative Example 6, respectively.

In addition, Figure 5 shows a comparison graph of the discharge delay time in the case of Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6 is shown In Table 1, the experimental results for the discharge delay time shown in FIG.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Comparative Example 5 Comparative Example 6 Zr content (ppm) 0 20 40 50 65 80 100 120 Discharge delay time (nsec) 352 338 298 194 152 129 197 285

As can be seen from FIG. 4, FIG. 5 and Table 1, when the content of zirconium is 65 to 80 ppm, not only the secondary electron emission coefficient is maximized, but also the discharge delay time is minimized.

That is, referring to FIG. 4, when the acceleration voltage for discharging is 180 V, the secondary electron emission coefficient is about 0.78 when the zirconium content is 0, but about 0.98 when the zirconium content is 65 ppm, It can be seen that the content of zirconium is about 0.93 when 80 ppm. In addition, when the content of zirconium 120ppm is about 0.82, it can be seen that the secondary electron emission coefficient is reduced than the content of zirconium is 65 ~ 80ppm.

Referring to FIG. 5 and Table 1, the discharge delay time criterion in which the black noise phenomenon occurs due to a long discharge delay time is about 230 nsec (indicated by a dashed-dotted line in the graph of FIG. 5). The content of zirconium is about 50 to 100ppm, in particular, it can be seen that the content of zirconium to minimize the discharge delay time is about 65 to 80ppm. That is, when the content of zirconium is 65ppm, the discharge delay time is 152nsec, and when the content of zirconium is 80ppm, the discharge delay time is 129nsec.

Looking at the above experimental results, it can be seen that the optimum content of zirconium satisfying the criteria of the secondary electron emission coefficient and the discharge delay time is 65 ~ 80ppm based on the magnesium oxide content.

On the other hand, if the zirconium (Zr) content of the protective layer 115 is formed so as to increase as the depth D from the surface of the protective layer 115 toward the dielectric layer 114 increases, the secondary electron emission coefficient increases and the secondary electron emission coefficient increases. The amount of electron emission is further increased.

Such a phenomenon can be confirmed by the secondary electron emission test results of the following Example 3 and Comparative Example 7.

Example 3

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, pellets were prepared from magnesium oxide (MgO), and the pellets were heat treated at 350 ° C., and then deposited by ion plating to form a protective layer. Then, zirconium (Zr) is doped and added to the formed protective layer, and the doping process is appropriately adjusted so that the content of the added zirconium has a concentration as shown in Table 2 according to the depth from the surface of the protective layer. And zirconium is added to the protective layer. Thereafter, the secondary electron emission coefficient was measured in the plasma environment measurement chamber with the substrate.

Comparative Example 7

After the electrode was formed on the substrate having a thickness of 2.8 mm by screen printing, the electrode was coated with PbO glass to form a dielectric layer having a thickness of 40 μm. Thereafter, zirconium (Zr) is added to magnesium oxide (MgO) to prepare a pellet. The amount of zirconium added at this time is added to have a concentration of 74 to 76 ppm as shown in Table 2 below. Thereafter, the pellets were heat-treated at 350 ° C. and deposited by an ion plating method to prepare a protective layer for the dielectric layer. The secondary electron emission coefficient was measured in the plasma environment measurement chamber with the substrate.

Depth from the surface of the protective layer (nm) 0 100 200 300 400 500 600 700 Zr concentration in Example 3 (ppm) 79 79 81 83 83 84 84 84 Zr concentration in Comparative Example 7 (ppm) 75 75 76 75 76 74 75 75

(The concentration of zirconium (Zr) in Table 2 is a value based on the content of magnesium oxide in the protective layer)

The results of the secondary electron emission coefficients of Example 3 and Comparative Example 7 are shown in the graph of Figure 6, Figure 6 is a comparison graph of the secondary electron emission coefficient according to the case of Example 3 and Comparative Example 7.

As shown in FIG. 6, as the depth D increases from the surface of the protective layer 115 toward the dielectric layer 114, the higher the content of zirconium Zr, the higher the secondary electron emission coefficient and the secondary electron emission amount. It can be seen that more. That is, it can be seen that, for all the acceleration voltages on which the experiment was performed, the secondary electron emission coefficient of Example 3 is larger than the secondary electron emission coefficient of Comparative Example 7.

Here, as the depth D increases from the surface of the protective layer 115 toward the dielectric layer 114, the content of zirconium Zr increases, and as the depth D increases, the zirconium continually increases. It does not mean that the content of Zr) is increased, but considering the overall thickness of the protective layer 115, it means that the content of zirconium (Zr) increases on average as the depth (D) increases.

That is, for example, even in the case of the concentration of zirconium in Example 3, the concentration of zirconium is the same as 79 ppm at the depths of 0 nm and 100 nm, and the concentration of zirconium is equal to 83 ppm at the depths of 300 nm and 400 nm. In the case of 500 nm, 600 nm and 700 nm, the concentration of zirconium is the same as 84 ppm, but when looking at the overall thickness of the protective layer from 0 to 700 nm, the average concentration of zirconium increases as the depth increases.

As described above, the deeper the depth D from the surface of the protective layer 115 is, the more the content of zirconium is, on average, the more the emission amount of secondary electrons becomes. However, also in that case, the content of zirconium (Zr) added is preferably in the range of 65 to 80 ppm based on the content of magnesium oxide, as described above. That is, if the content of zirconium in the protective layer 115 is in the range of 65 to 80 ppm, the deeper the depth (D) from the surface of the protective layer 115, the average amount of zirconium is gradually formed, It is possible to form an optimal protective layer in consideration of the secondary electron emission amount and the discharge delay time.

As described above, the plasma display panel 100 according to the embodiment of the present invention may include the protective layer 115 including zirconium (Zr), thereby increasing the generation rate of secondary electrons and lowering the driving voltage to improve luminous efficiency. .

In addition, while the content of zirconium included in the protective layer 115 according to the present embodiment is in the range of 65 to 80ppm, the deeper the depth from the surface of the protective layer 115 is formed to gradually increase the content of zirconium. As a result, the secondary electron emission can be further increased, and the discharge delay time can be further reduced.

As described above, the plasma display panel according to the present invention has a magnesium oxide protective layer containing zirconium, thereby increasing the emission amount of secondary electrons and reducing the discharge delay time.

 As such, when the secondary electron emission amount is increased, the driving voltage can be lowered to improve the luminous efficiency of the plasma display panel. Also, when the discharge delay time can be reduced as described above, high-speed addressing is possible, thereby allowing a single scan. The structure allows for the benefit of reducing scan drive costs.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (5)

A pair of substrates spaced at predetermined intervals and facing each other; A partition wall positioned between the pair of substrates and defining a discharge cell together with the pair of substrates; Discharge electrodes disposed between the pair of substrates; A dielectric layer formed to cover the discharge electrodes; A protective layer formed to cover at least a portion of the dielectric layer, the protective layer including magnesium oxide (MgO) and zirconium (Zr); A phosphor layer disposed in the discharge cell; And And a discharge gas in the discharge cell. The method of claim 1, The zirconium content is 65 ~ 80ppm based on the content of the magnesium oxide (MgO) plasma display panel. The method of claim 1, The content of the zirconium increases on average as the depth deepens from the surface direction of the protective layer toward the dielectric layer. The method of claim 3, Wherein a portion of the portion of the protective layer is less than or equal in content to the zirconium than the other portion that is relatively closer to the dielectric layer than the portion. The method of claim 1, The protective layer is manufactured by one process selected from the group consisting of a chemical vapor deposition (CVD) process, an E-beam process, an ion-plating process and a sputtering process. Plasma display panel.

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