KR100787436B1 - Flat panel display device - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a flat panel display device having an electron emitting portion in a divided form for limiting discharge in the inner region of the electrode and promoting discharge in the outer region of the electrode. In order to correspond to a first substrate, a second substrate spaced apart from and facing the first substrate, a first electrode and a second electrode disposed on the first substrate, and correspond to the first electrode and the second electrode. It is disposed and divided into a plurality of, and provides a flat panel display having an electron emitting unit for accelerating and emitting electrons as a voltage is applied to the first electrode and the second electrode.

Description

 Flat display device

1 is a cross-sectional view schematically showing a conventional plasma display panel.

2 is a partial cutaway perspective view schematically illustrating a part of a flat panel display device according to an exemplary embodiment of the present invention.

FIG. 3 is a side view seen from the III side of FIG. 2.

Explanation of symbols on the main parts of the drawings

211: first substrate 212: second substrate

220: partition 230: first electrode

231: second electrode 240: first dielectric layer

245: electron emission unit 246: base electrode

260: third electrode 270: second dielectric layer

280: phosphor layer

The present invention relates to a flat panel display device, and more particularly, to a flat panel display device having a divided electron emission unit.

Flat panel displays include Plasma Display Panels (PDPs), Thin Film Transistors-Liquid Crystal Displays (TFT-LCDs), Organic Light Emitting Diodes (OLEDs), Field Emission Displays (FEDs), and Surface-conduction Electron- emitter Display). Among them, the plasma display panel refers to a flat panel display device that realizes an image by using a gas discharge phenomenon, and has not only excellent characteristics of a large screen, high definition, ultra-thin, light weight, and wide viewing angle, but also simpler manufacturing method than other flat panel display devices. It is easy to scale up and has attracted much attention as a large flat panel display device.

Plasma display panel displays images such as images by emitting phosphors by ultraviolet rays generated during gas discharge, and direct current type, alternating current type and hybrid type according to the applied discharge voltage. They are classified into counter discharge type and surface discharge type according to the discharge structure.

1 is a cross-sectional view of a portion of a surface discharge plasma display panel. The plasma display panel of FIG. 1 includes a front electrode 111, a rear substrate 112, a partition wall 120, a transparent electrode 130 made of a material such as indium-tin oxide, and a conductive material such as a metal. And a bus electrode 135, a front dielectric layer 140, a magnesium oxide (MgO) protective layer 150, an address electrode 160, a back dielectric layer 170, and a phosphor layer 180.

In order to facilitate the understanding in FIG. 1, the lower part of the partition wall 120 is rotated by 90 degrees to be parallel to the upper part of the protective layer. The upper part of the protective layer including the MgO protective layer 150 and the lower part of the partition including the partition 120 are arranged to cross each other in the actual plasma display panel.

Referring to FIG. 1, when a voltage is applied to a pair of sustain electrodes 130, wall charges are accumulated in the front dielectric layer 140 to generate a discharge. The electrons are continuously supplied to the discharge cells by applying a voltage to the electrodes. These electrons collide with neutral particles of the discharge gas inside the cell, resulting in ionized particles. At this time, the ionized particles emit vacuum ultra violet (VUV), which excites the phosphor 180 to obtain visible light.

However, in this process, ions irrelevant to light emission are generated and accelerated, and the energy consumed by this takes up more than half of the total energy. The energy used to generate and accelerate ions reduces the discharge efficiency.

In addition, when the discharge occurs between the electrodes constituting the electrode pair, the discharge is generated first in the inner region of the electrodes having short discharge paths, which causes the discharge efficiency not to be evenly distributed throughout the cell.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flat panel display device having a split electron emission unit in order to solve the above problems and to limit the discharge in the inner region of the electrode and to promote the discharge in the outer region of the electrode. It is done.

In order to achieve the above object and other objects, the present invention provides a first substrate, a second substrate disposed to face the first substrate spaced apart from each other, a first electrode and a second electrode disposed on the first substrate, A flat panel display device which is disposed to correspond to the first electrode and the second electrode and is divided into a plurality of parts, and has an electron emission unit for accelerating and emitting electrons as a voltage is applied to the first and second electrodes. To provide.

Herein, the electron emission unit may be oxidized porous silicon.

Here, the electron emitting unit may be divided into a plurality of directions in which the first electrode and the second electrode extend.

The first electrode and the second electrode may be disposed together on the first substrate or the second substrate.

Here, the first electrode and the second electrode may be disposed on the first substrate and the second substrate facing each other.

The flat panel display device may further include a dielectric layer between the first electrode, the second electrode, and the electron emission unit.

The flat panel display may further include a base electrode disposed between the dielectric layer and the electron emission unit to correspond to the electron emission unit. The base electrode may include aluminum (Al) or silver (Ag).

 The flat panel display apparatus may further include a partition wall partitioning cells and a phosphor layer disposed in the cells in a space formed between the first substrate and the second substrate.

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

2 is an exploded perspective view schematically illustrating a part of a flat panel display device according to an exemplary embodiment of the present invention. FIG. 3 is a side view seen from the III side of FIG. 2.

Referring to FIG. 2, a flat panel display device according to an exemplary embodiment of the present invention may include a first substrate 211, a second substrate 212, a partition wall 220, a first electrode 230, and a second electrode 231. ), A first dielectric layer 240, an electron emission unit 245, a base electrode 246, a third electrode 260, a second dielectric layer 270, and a phosphor layer 280.

Before describing each component in detail, the direction is defined, in which the upper side of FIG. 2 is the front side (front side) in which an image is displayed, and the lower side is the rear side (back side) of the flat panel display device.

The first substrate 211 and the second substrate 212 are disposed to face each other while being spaced apart from each other. The first substrate 211 and the second substrate 212 may be formed of a glass substrate having excellent visible light transmittance, and may be colored to improve clear room contrast. In addition, the first substrate 211 and the second substrate 212 may be formed of plastic and may have a flexible structure.

In the space formed between the first substrate 211 and the second substrate 212, a barrier rib 220 for dividing the cell is disposed. The partition walls extend in one direction and are spaced apart from each other so that the cells are partitioned. As seen from the upper side of the separation yarn attempt of FIG. 2, the partition wall is stripe-shaped extending in one direction. However, the shape of the partition wall is not limited thereto, and may be formed in various shapes. For example, the partition wall may be formed also in a direction orthogonal to the formation direction of the partition wall so that the partition wall may be formed so that the grid-shaped discharge space is partitioned when viewed from above. The partition wall 220 serves to prevent electrical and optical crosstalk between cells.

The first electrode 230 and the second electrode 231 are disposed on the rear surface of the first substrate 211. The first electrode 230 and the second electrode 231 are strictly referred to as a combination of the transparent electrodes 230 and 231 and the metal bus electrode 235, respectively. In the case of the transparent electrode, the material may be indium-tin oxide. The transparent electrode may also be referred to as an ITO electrode. ITO has a high light transmittance. In the first electrode 230 and the second electrode 231, the transparent electrode is formed wide, while the metal bus electrode 235 is formed small at the side end of one surface of the transparent electrode. Meanwhile, the first electrode 230 and the second electrode 231 are not only formed on the same plane as in FIG. 2 but also disposed on the first substrate 211 and the second substrate 212 so as to face each other. In this case, the third electrode 260 may not exist.

The first dielectric layer 240 is disposed on the rear surface of the first electrode 230 and the second electrode 231 to cover the first electrode 230 and the second electrode 231. The first dielectric layer 240 is formed of a transparent material and functions to limit the discharge current to maintain the glow discharge and to accumulate wall charges. The material used as the dielectric has high withstand voltage and high visible light transmittance.

An electron emission part 245 is disposed on the rear surface of the first dielectric layer 240 so as to correspond to the first electrode 230 and the second electrode 231, respectively. In the flat panel display device according to an embodiment of the present invention, the electron emission unit 245 corresponding to one of the first electrode 230 and the second electrode 231 may include the first electrode 230 and the second electrode. The electrodes 231 are spaced apart into three pieces divided in the extending direction. The electron emission unit 245 is made of oxidized porous silicon (OPS). More subdivided, it may consist of oxidized porous polysilicon or oxidized porous amorphous silicon. A process of discharging in the electron emitting unit 245 will be described later.

A base electrode 246 is disposed between the electron emission unit 245 and the first dielectric layer 240 to correspond to the electron emission unit 245. However, in the flat panel display device according to another exemplary embodiment of the present invention, the electron emission layer 245 may be in direct contact with the first dielectric layer 240 without the base electrode.

Now, the configuration and function of the second substrate 212 and its periphery shown in FIG. 2 will be described.

The third electrode 260 is disposed on the front surface of the second substrate 212. The third electrode 260 extends in the same direction as the partition wall 220, and each third electrode 260 is disposed between the partition walls 220. The second dielectric layer 270 is disposed on the front surface of the third electrode 260 to cover the third electrode 260. In the flat panel display device according to the exemplary embodiment of the present invention, the third electrode is responsible for an address function for designating a discharge cell in which discharge occurs. The second dielectric layer 270 serves to protect the address electrode and has a high dielectric breakdown strength. In addition, the second dielectric layer 270 is made of a material having high light reflectance.

On the other hand, a fluorescent material is applied to the surface on which the partition wall 220 is formed and the second dielectric layer 270 exposed below the phosphor layer 280. In the flat panel display device according to an embodiment of the present invention, the material forming the phosphor layer is a material that generates visible light by receiving ultraviolet rays. However, in the flat panel display device according to the embodiment of the present invention, the phosphor layer is not limited thereto, and visible light may be generated by collision with electrons other than ultraviolet rays. Alternatively, the phosphor layer may include a quantum dot.

The cells are generally filled with a gas containing xenon (Xe). Alternatively, the gas may include nitrogen (N 2), deuterium (H 2), carbon dioxide (CO 2), hydrogen (H 2), carbon monoxide (CO), krypton (Kr), or air (air), and the phosphor layer 280 ) May be formed on an outer surface of the first substrate 211 or the second substrate 212. In the flat panel display device according to an embodiment of the present invention, the gas filled in the cell serves as a discharge gas. However, the gas of the flat panel display device according to an exemplary embodiment of the present invention is not limited thereto, but does not reach an energy level such that discharge is caused by external energy such as an electron beam, but reaches an extent to which the gas is excited, thereby generating ultraviolet rays. It may be to.

Now, referring to FIG. 3, a process of accelerating and releasing electrons during discharge in the divided electron emission unit 245 will be described. The electron-emitting part 245 is a layer for accelerating and supplying electrons necessary for discharging, and an oxidized porous silicon (OPS) is used as the material in the embodiment of the present invention. As another modification, carbon nanotubes, Boron Nitride Bamboo Shoot (BNBS), or the like may be used.

First, when voltage is applied to the first electrode 230 and the second electrode 231, the voltage is also applied to the base electrode 246 via the first dielectric layer 240. When a voltage is applied to the base electrode 246, a voltage is also applied to the electron emission unit 245 to inject electrons into the electron emission unit 245. When the OPS is used as the electron emission unit, when a voltage is applied to the electrode, the voltage is also applied to the OPS and electrons are injected into the OPS layer. OPS is formed by the collection of silicon nanocrystals. The diameter of silicon nanocrystals is about 5 nm, which is sufficiently small compared to the average free path of electrons (about 50 nm), so the collision probability of electrons injected into the OPS layer is very small. As a result, the electrons pass through most of the nanocrystalline silicon and reach the interface. Between the nanocrystalline silicon is covered with a thin oxide film. This oxide film is so thin that electrons can easily pass through it. When a voltage is applied to the OPS, most of the voltage is caught by this oxide film to form a strong electric field region. Since electrons are accelerated every time they pass through the oxide film, electrons that reach the surface while repeatedly passing through the oxide films have energy corresponding to the energy of electrons discharged when a high voltage is applied without OPS. In other words, when the OPS layer is provided, electrons having sufficient energy can be obtained even when a low voltage is applied to the electrode.

When the discharge occurs through the electron emitting portion 245 made of OPS and discharged to the discharge cell, the discharge occurs first in the inner path 247. This is because the shorter the discharge path, the discharge occurs at a lower voltage. As the applied voltage increases, the discharge occurring in the inner path 247 extends to the intermediate path 248 and the outer path 249. When discharge occurs in the inner path 247, positive ions are accumulated on the surface of the OPS on the cathode of the first electrode 230 or the second electrode 231, and when it reaches a certain amount, the external applied voltage is canceled to offset the applied voltage. It will not reach, causing the discharge to stop.

If the electron emission portion corresponding to one electrode is integrally formed, it takes more time than the split type electron emission portion used in the embodiment of the present invention to stop the discharge due to the accumulation of the above ions. This is because the movement of electrons occurs in the OPS forming the electron emission unit. In other words, in the case of the integral electron emitting part, the electrons in the outer part move inward to offset part of the ions accumulated in the inner part, so that the discharge of the inner part lasts for a certain time.

However, as described above, since the discharge of the inner path 247 has a lower discharge efficiency than the discharge of the outer path 249, it is not preferable that the discharge of the inner part lasts long.

In order to terminate the discharge of the inner path 247 early and to quickly start the discharge of the outer path 249, the split type electron emission unit 245 is used as in the flat panel display device according to the exemplary embodiment. . According to this, since the electron emitting part of the inner part, the electron emitting part of the middle part, and the electron emitting part of the outer part are independent of each other, the discharge is first started in the electron emitting part of the inner part. You can't get electrons. Therefore, the discharge of the inner path 247 is terminated early and the discharge passes to the intermediate path 248 and the outer path 249.

As such, the use of the electron emission unit in the form of a plurality of pieces may be applied regardless of the structure of the electrode or panel. In particular, it can be effectively applied when the light emission intensity varies depending on the position in the discharge cell.

According to the flat panel display apparatus according to the present invention, by using the electron emitting unit divided into several pieces it is possible to limit the discharge occurring in the inner portion of the first electrode and the second electrode and to enlarge the discharge to the outside, flat panel display It is possible to increase the discharge efficiency in the device and to cause the discharge to occur uniformly in the discharge cell.

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 (9)

A first substrate; A second substrate spaced apart from the first substrate to face each other; First and second electrodes disposed on the first substrate; It is disposed to correspond to the first electrode and the second electrode and is divided into a plurality. The electrons are accelerated and emitted as voltage is applied to the first and second electrodes. an electron emission unit made of silicon); And And a substrate disposed between the first substrate and the second substrate and excited by the electrons. delete The method of claim 1, The electron emission unit is divided into a plurality of flat panel display in the direction in which the first electrode and the second electrode extends. The method of claim 1, And the first electrode and the second electrode are disposed together on the first substrate or the second substrate. The method of claim 1, And the first electrode and the second electrode are disposed on the first substrate and the second substrate facing each other. The method of claim 1, And a dielectric layer disposed to cover the first electrode and the second electrode to protect the first electrode and the second electrode. The method of claim 6, And a base electrode disposed between the dielectric layer and the electron emission unit to correspond to the electron emission unit. The method of claim 7, wherein And the base electrode includes aluminum (Al) or silver (Ag). The method of claim 1, A partition wall partitioning cells in a space formed between the first substrate and the second substrate; And And a phosphor layer for emitting light disposed in the cells.

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