KR20070006512A - Plasma display panel and method of forming the same - Google Patents

Abstract

A plasma display panel and a method for forming the same are provided to lower a breakdown voltage of next discharge and reduce power consumption by using a material having a high generation degree of charged particles. A plasma display panel includes two substrates(110,210) disposed opposite to each other in order to form a sealed space therebetween, a barrier rib(440) for defining the space between the substrates, a driving electrode for displaying images, discharge gas for filling up the space, and a phosphor layer(450) laminated partially on the substrate and the barrier rib. The driving electrode is covered with a dielectric. A high efficient electron emission material layer having high secondary electron emission efficiency is formed on a surface of the dielectric corresponding to the driving electrode applied to display discharge.

Description

Plasma display panel and method of forming the same

1 is a perspective view showing an example of a structure of a discharge cell of a conventional surface discharge type plasma display panel;

Figure 2 is a perspective view showing the structure of the discharge cell in an embodiment of the present invention, Figure 3 is a cross-sectional view taken along line AA of Figure 2,

4 is a cross-sectional view showing the structure of a discharge cell in another embodiment of the present invention;

5A to 5C are cross-sectional views illustrating main steps of forming a sustain electrode and a high efficiency electron emission material layer on a front substrate in an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

110: front substrate 125, 135: bus electrode pattern

121,131: transparent electrode pattern 140,230: dielectric layer

120,130: sustain electrode 150,350,550: protective film

210: back substrate 220: address electrode

240, 440: bulkhead 250, 450: phosphor layer

360: carbon nanotube layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel and a method of forming the same, and more particularly, to an electrode and an electron emission film structure related to discharge in a plasma display panel.

Plasma display panels are formed by forming electrodes on two opposing substrates, overlapping them at regular intervals, injecting a discharge gas therein, and sealing the plasma display panel (PDP). Refers to a flat panel display device. The plasma display device is formed by forming a plasma display panel and installing elements necessary for screen realization such as a driving circuit connected to each electrode of the panel.

In the plasma display panel, many pixels for displaying a screen are arranged in a matrix form. In the plasma display panel, each pixel is driven in a manner of applying a voltage to a horizontal electrode and a vertical electrode that intersect in a lattice state when viewed from above without an active element for driving the pixel, that is, a passive matrix method. The plasma display panel may be classified into a direct current type and an alternating current type according to the shape of the voltage signal for driving each electrode, and may be divided into an opposing type and a surface discharge type according to the arrangement of the two electrodes to which the sustain discharge voltage is applied.

In the case of the alternating current type, since the electrode is covered with the dielectric layer, it naturally has a capacitance, the current flowing through the electrode is limited, and the electrode is easily protected from the ion shock during discharge. As a result, the electrode lifetime is also long. When the protective film is formed on the dielectric layer covering the electrode, the charged particles in the cell strike the dielectric layer covering the electrode due to the voltage applied in the discharge cell, thereby deteriorating the dielectric layer and exposing or breaking the electrode, thereby reducing the life of the display device. You can prevent it well.

1 is a perspective view showing an example of a structure of a discharge cell of a conventional surface discharge type plasma display panel. Looking at the configuration briefly, the address electrode 220 is provided on the rear substrate 210 shown below, the dielectric layer 230 is formed on the address electrode, and the partition wall 240 is formed on the dielectric layer 230 again. do. The phosphor layer 250 is stacked on the lower substrate on which the partition wall is formed.

The front substrate 110 of the upper substrate 110 aligned with the rear substrate 210 to form a panel forms a screen of the panel, and two types of sustain electrodes 120 and 130 are formed on the inner surface of the front substrate 110. The sustain electrode is formed to cross the address electrode 220 vertically, and includes the transparent electrode patterns 121 and 131 and the bus electrode patterns 125 and 135. The dielectric layer 140 is formed on the entire surface of the substrate on which the sustain electrode is formed, and the passivation layer 150 is again stacked on the dielectric layer 140.

At this time, when the protective film is formed too thick, it takes a long time to laminate the protective film on the substrate, there is a problem that the material and the process cost increases. In addition, when the transparency of the protective film is low, the amount of visible light emitted to the front side is reduced and the luminance is reduced. Therefore, the protective film is a thin film that must withstand the impact of the charged particles, it is preferable that the transparent. Magnesium oxide (MgO) is used a lot as a protective film. Magnesium oxide has the advantage of being able to withstand the impact of accelerated charged particles well, and also emit a lot of secondary electrons upon particle collision. When a large amount of secondary electrons are emitted from the passivation layer, charged particles generated during address discharge in a surface discharge plasma display panel having a discharge cell structure as shown in FIG. 1 are accumulated around sustain electrodes in the discharge cell and maintained by a memory effect. There is an advantage that the discharge start voltage can be lowered at the time of discharge.

However, in accordance with the trend of lowering power and lowering the driving voltage, the use of a material having a secondary electron emission coefficient higher than that of the conventional magnesium oxide is strongly required to reduce the driving voltage. At the same time, it is required that these materials have the advantages of conventional Magnesium oxide.

However, finding a material that satisfies these characteristics or advantages at the same time is very difficult and problematic.

An object of the present invention is to provide a plasma display panel adopting a material having a higher charge particle generation characteristic than that of magnesium oxide used in a conventional plasma display panel and a method of forming the same.

In addition, another object of the present invention is to provide a plasma display panel and a method for forming the same, wherein the secondary electron emission material can emit visible light generated in the discharge cell to the front.

An object of the present invention is to provide a high efficiency plasma display panel capable of lowering a discharge start voltage and lowering power consumption, and a method of forming the same.

Plasma display panel of the present invention for achieving the above object is, a plurality of driving for discharging the discharge cell is provided between the two substrates, the partition wall is partitioned between the two substrates, partitioning the area of the discharge cell, the two substrates An electrode, two substrates, and a discharge gas filled in a space sealed with a sealing material and a phosphor layer provided in the discharge cell, wherein the driving electrode is covered with a dielectric and corresponds to at least one electrode intervening in display discharge among the driving electrodes; The electron emitting material layer having a higher electron emission efficiency than that of magnesium oxide is laminated on the dielectric surface of the region.

In the present invention, the high-efficiency electron emission material layer is made of an opaque material, and may be formed to overlap at least a portion of the driving electrode with the opaque bus electrode of the sustain electrode.

In the present invention, the driving electrode is a surface discharge type, two types of sustain electrodes may be formed on the front substrate to which most of the visible light is emitted. In this case, the high efficiency electron emission material layer may be formed in a region overlapping to include the bus electrode of the sustain electrode when viewed from the front, and the magnesium oxide layer may be laminated on the entire surface of the dielectric substrate.

In the present invention, the material layer having a high electron emission efficiency may be a material layer including carbon nanotubes (CNT), MgF ₂ .

In the plasma display panel forming method of the present invention, forming a transparent electrode pattern on a front substrate, forming a bus electrode pattern overlapping the transparent electrode pattern, and forming a dielectric layer on the substrate surface on which the transparent electrode pattern and the bus electrode pattern are formed. And forming a high efficiency electron emission material layer in a region at least partially overlapping with the bus electrode pattern on the surface of the dielectric layer.

In the method of the present invention, the bus electrode pattern forming step and the transparent electrode pattern forming step may be reversed, and before or after the step of forming the high efficiency electron emission material layer of the present invention, the entire dielectric layer or the region in which the high efficiency electron emission material layer is formed. The method may further include selectively forming a protective film on the outer region.

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

FIG. 2 is a cross-sectional perspective view illustrating a barrier rib and an electrode structure of a discharge cell in one embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line AA of FIG.

2 and 3, an opaque address electrode 220 made of metal is formed side by side in the longitudinal direction of the screen, and a dielectric layer 230 is formed on the address substrate 220. A partition wall is formed over the dielectric layer 230. In the present embodiment, the partition wall 440 is formed in a lattice shape to divide each discharge cell in all directions, but only a longitudinal partition wall parallel to the address electrode 220 may be formed, and a horizontal partition wall may not be formed.

The phosphor layer 450 is stacked on the back substrate 210 on which the partition wall 440 is formed. In the phosphor layer, three colors such as RGB are repeatedly installed in a row of discharge cells connected in a longitudinal direction. The phosphor is laminated on the partition surface and the inner surface of the rear substrate.

Meanwhile, sustain electrodes 120 and 130 are installed on the front substrate 110 in the horizontal direction with respect to the screen. The sustain electrode includes the transparent electrode patterns 121 and 131 and the bus electrode patterns 125 and 135, and the scan sustain electrode 120 and the common sustain electrode 130 pass through each discharge cell. In each discharge cell, the bus electrode patterns 125 and 135 are formed to be biased upward and downward, and one end of the transparent electrode patterns 121 and 131 overlaps with the bus electrode patterns 125 and 135 in each discharge cell, and the other end thereof is in the longitudinal direction of the discharge cell. Stretched towards the center

A dielectric layer 140 is stacked over the entire surface of the substrate on which the sustain electrodes 120 and 130 are formed. The dielectric layer 140 is formed of transparent glass so that visible light generated in the discharge cell can be emitted at a high rate without being lost through the front substrate 110. The carbon nanotube layer 360 may overlap the bus electrode patterns 125 and 135 among the sustain electrodes on the dielectric layer 140, but may be disposed in a divided pattern for each discharge cell. In each discharge cell, a magnesium oxide (MgO) film is formed on the surface of the dielectric layer 140 between the bus electrode patterns of the two sustain electrodes as the passivation layer 350. In this configuration, the carbon nanotube layer overlaps with the bus electrode, which is also opaque even if it is opaque, and thus does not cause additional loss in the aperture ratio of the discharge cell. When the carbon nanotube layer 360 is divided into discharge cells, secondary charged particles accumulated between adjacent discharge cells are diffused along the conductive carbon nanotube layer 360 to reduce the degree of integration of secondary charged particles. You can prevent it.

In addition, since the carbon nanotube layer 360 overlaps with the bus electrode patterns 125 and 135 which are some of the most concentrated electric fields and actively discharges, the carbon nanotube layer 360 generates a large number of secondary charged particles in the address discharge and accumulates in the surroundings, The effect of reducing the discharge start voltage can be enhanced. Of course, the magnesium oxide protective film 350 has a function of generating and accumulating secondary charged particles on the transparent electrode patterns 121 and 131 as in the related art. In particular, during the sustain discharge, the magnesium oxide protective film 350 actively discharges in the gap between the transparent electrode patterns 121 and 131. It generates and accumulates secondary charged particles in.

The carbon nanotube layer 360 is formed by mixing carbon nanotubes with a binder, and a plurality of fine carbon nanotubes protrude from the surface thereof.

When the basic structure such as the partition wall 440 and the electrode is formed on the back substrate 210 and the front substrate 110 as described above, the two substrates are aligned and sealed. For sealing, a fleet glass (not shown) for sealing mainly containing low melting point glass as a main component is used at the periphery of the substrate. After sealing is completed, the air inside is removed and discharge gas injection for plasma discharge is performed. After the discharge gas is injected, the injection port is fused to seal the space in which the discharge gas is injected.

In this embodiment, carbon nanotubes are used as the high efficiency electron emission material layer of the present invention, but other carbon compounds or metal oxides may be used. In addition, in the present embodiment, the carbon nanotube layer and the magnesium oxide protective layer are laminated by dividing the regions so as not to overlap the front substrate in the discharge cell, but as shown in the other embodiment of FIG. 4, first, the carbon nanotube layer 360 is formed. It is also possible to deposit the magnesium oxide protective film 550 over the dielectric layer 140 before or on the carbon nanotube layer. However, in this case, the ends of the carbon nanotubes are preferably formed to partially protrude over the magnesium oxide protective film 550.

In addition, although the surface discharge type three-electrode structure is shown in the present embodiment, any type of discharge electrode structure that induces secondary electron emission upon discharge and lowers the voltage of the next discharge by using the charged particles generated at this time has high efficiency electrons on the surface of the dielectric layer outside the constant electrode. The present invention can be applied in the form of an emitter layer. This embodiment also exemplifies the stripe arrangement of the three phosphors for the discharge cell arrangement in each pixel for color display, but all of the delta arrangements may be possible.

Hereinafter, the method of the present invention will be described in more detail step by step. Since the process of forming the back substrate in the method of the present invention can be made similar to the conventional general methods, the focus is on the process of forming the front substrate.

First, sustain electrodes 120 and 130 are formed on the front substrate 110 as shown in FIG. 5A. There may further be forming a buffer layer (not shown) to facilitate electrode formation on the glass substrate prior to forming the storage electrode. The transparent electrode patterns 121 and 131 and the bus electrode patterns 125 and 135 are sequentially formed on the substrate.

The transparent electrode patterns 121 and 131 may be formed by forming an indium tin oxide (ITO) layer on the entire surface of the substrate by deposition or sputtering, and then patterning the same using photolithography. The bus electrode patterns 125 and 135 are formed to overlap the transparent electrode pattern, and in order to increase the opening ratio of the discharge cells, the bus electrode patterns 125 and 135 may be formed to have a narrow line width of about 70 micrometers, but may be formed of a highly conductive metal. The bus electrode pattern may be directly formed through printing, or may be obtained by applying an electrode material including a photoreactive material to the substrate as a whole and patterning the photolithography. The metal film may be laminated first, followed by photolithography using a photoresist to obtain a bus electrode pattern.

Referring to FIG. 5B, the dielectric layer 140 is stacked on the entire surface of the substrate on which the storage electrodes 120 and 130 are formed. The dielectric layer 140 may be formed by chemical vapor deposition or the like, but may be formed through a conventional printing technique. The dielectric layer 140 is formed using a material having a low reflection or absorption when visible light having a corresponding wavelength generated by ultraviolet rays emitted from the plasma discharge in the discharge cell passes through the dielectric layer 140. Can be. The dielectric layer 140 may be formed thicker than the transparent electrode or bus electrode pattern, thereby eliminating a step that occurs when the sustain electrodes 120 and 130 are formed on the substrate, thereby forming a planarized surface on the substrate.

Subsequently, a high efficiency electron emission material pattern is formed in each discharge cell so as to overlap the bus electrode patterns 125 and 135. This pattern may be formed of the carbon nanotube layer 360. The carbon nanotube layer 360 mixes the carbon nanotubes with a binder and a solvent to form a material having a viscosity in a slurry form, and similarly forms a pattern by printing, photolithography, or the like similar to bus electrode formation. In printing, inkjet printing is also possible.

Since the first pattern is made of a fluid material layer, the solvent is removed through a process such as firing to form a pattern consisting of a binder and carbon nanotubes. Many carbon nanotubes are exposed on the surface of this pattern and can be in close contact with the surface. In this case, the carbon nanotubes may be formed to protrude outward from the surface formed with the binder through electrostatic processing.

Referring to FIG. 5C, the carbon nanotube layer 360 is formed to overlap with the bus electrodes 125 and 135 in each discharge cell. The dielectric layer 140 between the carbon nanotube layers is disposed between the transparent electrode pattern and the transparent electrode pattern. The passivation layer 350 is formed to cover the gap. The passivation layer 350 may be usually made of magnesium oxide. The protective film may be formed on the entire surface of the substrate, as illustrated. The magnesium oxide layer can usually be formed by ion beam deposition, sputtering, or the like. The magnesium oxide film is formed to a thickness of 6000 to 7000 angstroms thinner than 1 micrometer to increase the aperture ratio on the screen. In order to form a pattern in a limited area between the carbon nanotube layers 360, a patterning operation using photolithography may be further performed in a fully stacked state.

According to the present invention, charged particles can be accumulated around the electrode through a material having higher charged particle generation characteristics than that of conventional magnesium oxide, thereby lowering the discharge start voltage of the next discharge and lowering power consumption.

In addition, according to the configuration, the secondary electron emission material may be formed to overlap with the opaque bus electrode to narrow the radiation surface of the visible light generated in the discharge cell so that the sustain discharge can be easily performed without dropping the aperture ratio.

Claims (11)

Two substrates spaced at regular intervals to form a sealed space together with a surrounding sealing material, partition walls partitioning the space between the two substrates, a driving electrode for displaying an image, a discharge gas filling the space, and the substrate; A plasma display panel comprising a phosphor layer laminated on at least part of a partition wall surface, The driving electrode is covered with a dielectric, and a high-efficiency electron emission material layer having a high secondary electron emission efficiency is formed on the surface of the dielectric in the region corresponding to one electrode among the driving electrodes at least involved in display discharge. And a plasma display panel. The method of claim 1, The high efficiency electron emission material layer is made of an opaque material, And at least a part of a width of the driving electrode overlapping with an opaque bus electrode of the sustain electrode. The method according to claim 1 or 2, The driving electrode includes a three-electrode surface discharge type and includes two types of sustain electrodes, and the sustain electrodes are formed on a front substrate forming a screen. The method of claim 3, wherein Wherein the high efficiency electron emission material layer is formed on the front substrate so as to overlap with the bus electrode of the sustain electrode, and a magnesium oxide layer is entirely laminated on the front substrate on which the high efficiency electron emission material layer is formed. The method of claim 3, wherein The high efficiency electron emission material layer is formed on the front substrate so as to overlap with the bus electrode of the sustain electrode, and a magnesium oxide layer is stacked between the areas where the high efficiency electron emission material layer is formed in each discharge cell. Plasma display panel. The method of claim 1, And the high efficiency electron emission material layer is made of a component including carbon nanotubes. The method of claim 1, The high efficiency electron emission material layer is formed so as to be separated for each discharge cell. Forming a transparent electrode pattern on the front substrate; Forming a bus electrode pattern on the front substrate; Forming a dielectric layer on the front substrate on which the transparent electrode pattern and the bus electrode pattern are formed; And forming a high efficiency electron emission material layer in a region of the dielectric layer at least partially overlapping the bus electrode pattern. The method of claim 8, Before or after the forming of the high efficiency electron emission material layer, the method of forming a plasma display panel further comprises selectively forming a protective film over the entire dielectric layer or in a region other than the region where the high efficiency electron emission material layer is formed. . The method of claim 8, Forming the high efficiency electron emission material layer is a step of mixing the high efficiency electron emission material with a binder and a solvent to form a slurry, Forming a pattern of a highly efficient electron emission material layer in a corresponding region of the front substrate by a printing technique using the slurry; and And subjecting the pattern to plastic processing to remove the solvent dependently. The method of claim 9, The high efficiency electron emitting material includes carbon nanotubes, And processing the carbon nanotubes protruding from the surface by electrostatic machining on the surface of the pattern.

Images