KR100719574B1 - Flat panel display device and Electron emission device - Google Patents

Abstract

The present invention includes a first substrate and a second substrate disposed to face each other at regular intervals; A plurality of partition walls provided between the first substrate and the second substrate and partitioning a space between the first substrate and the second substrate to form a plurality of cells; An excitation gas filled in the cells; A phosphor layer formed on an inner wall of the cells using a quantum dot (QD); A plurality of first electrodes formed on an inner surface of the first substrate; A plurality of second electrodes formed on an inner surface of the second substrate in a direction crossing the first electrodes; A plurality of third electrodes formed on the first electrodes; And a first electron acceleration layer formed between the first electrode and the third electrode to emit a first electron beam that excites the excitation gas into the cell as a voltage is applied to the first electrode and the third electrode. It provides a flat panel display device having a.

Description

Flat panel display device and Electron emission device

1 is an exploded perspective view of a conventional plasma display panel.

2A and 2B are cross-sectional views illustrating the plasma display panel of FIG. 1 cut in the horizontal and vertical directions, respectively.

Figure 3 schematically shows the structure of a quantum dot used as the phosphor of the present invention.

4 is a schematic cross-sectional view of a flat panel display device according to an embodiment of the present invention.

5 is a diagram illustrating an energy level of xenon (Xe).

6 is a schematic cross-sectional view showing a modification of the flat panel display device according to the present invention.

7 is a schematic cross-sectional view showing an embodiment of an electron emitting device according to the present invention.

<Explanation of symbols for the main parts of the drawings>

110 first substrate 113 bulkhead

114 ... cell 115 ... phosphor layer

120 ... second substrate 131 ... first electrode

132 ... second electrode 133 ... third electrode

140.Electron Acceleration Layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device and an electron emission device, and more particularly, to a flat panel display device and an electron emission device capable of lowering a driving voltage and improving luminous efficiency.

Plasma Display Panel (PDP), which is a type of flat panel display device, is an apparatus for forming an image by using an electric discharge, and its use is increasing day by day because of its excellent display performance such as brightness and viewing angle. In the plasma display panel, gas discharge occurs between the electrodes by a direct current or an alternating voltage applied to the electrodes, and phosphors are excited by ultraviolet rays generated in the discharge process to emit visible light.

The plasma display panel may be classified into a plasma display panel having a facing discharge structure and a plasma display panel having a surface discharge structure according to the arrangement structure of the electrodes. In a plasma display panel having an opposite discharge structure, two pairs of sustain electrodes are disposed on an upper substrate and a lower substrate, respectively, so that discharge occurs in a direction perpendicular to the substrate. In the plasma display panel having a surface discharge structure, two pairs of sustain electrodes are disposed on the same substrate so that discharge occurs in a direction parallel to the substrate.

1 shows a plasma display panel of a conventional AC type surface discharge structure. 2A and 2B illustrate cross-sectional views of the plasma display panel of FIG. 1 cut in the horizontal and vertical directions.

1, 2A and 2B, the lower substrate 10 and the upper substrate 20 are disposed to face each other at regular intervals to form a discharge space in which plasma discharge occurs. A plurality of address electrodes 11 are formed on an upper surface of the lower substrate 10, and the address electrodes 11 are filled by the first dielectric layer 12. A plurality of barrier ribs are formed on the upper surface of the first dielectric layer 12 to form a plurality of discharge cells 14 by dividing a discharge space, and to prevent electrical and optical cross talk between the discharge cells 14. 13) is formed. Phosphor layers 15 of red (R), green (G), and blue (B) are respectively coated on the inner walls of the discharge cells 14. In addition, a discharge gas including xenon (Xe) is generally filled in the discharge cells 14.

 The upper substrate 20 is a transparent substrate through which visible light can pass and is coupled to the lower substrate 10 on which the partitions 13 are formed. On the lower surface of the upper substrate 20, a pair of sustain electrodes 21a and 21b are formed in a direction orthogonal to the address electrodes 11 for each discharge cell 14. Here, the sustain electrodes 21a and 21b are mainly made of a transparent conductive material such as indium tin oxide (ITO) to transmit visible light. In order to reduce the line resistance of the sustain electrodes 21a and 21b, bus electrodes 22a and 22b made of metal are formed on the bottom surfaces of the sustain electrodes 21a and 21b. It has a narrower width than). The sustain electrodes 21a and 21b and the bus electrodes 22a and 22b are buried by the transparent second dielectric layer 23. A protective film 24 made of magnesium oxide (MgO) is formed on the bottom surface of the second dielectric layer 23. The protective layer 24 prevents damage to the second dielectric layer 23 by sputtering of plasma particles and lowers the discharge voltage by emitting secondary electrons.

The driving of the plasma display panel having the above structure is largely divided into driving for address discharge and driving for sustain discharge. The address discharge occurs between the address electrode 11 and one of the pair of sustain electrodes 21a and 21b, and wall charge is formed. Next, the sustain discharge is caused by the potential difference between the pair of sustain electrodes 21a and 21b, and the phosphor layer 15 is excited by the ultraviolet rays generated from the discharge gas during the sustain discharge to emit visible light. The emitted light is emitted through the upper substrate to form an image that can be recognized by the user.

However, in the conventional plasma display panel as described above, ultraviolet rays are generated while the discharge gas is ionized and the xenon Xe ^* of the excited state is stabilized during the plasma discharge. Therefore, conventionally used light emitting materials require high energy enough to ionize the discharge gas, have a large driving voltage, and low luminous efficiency.

The present invention has been made to solve the above problems, a flat panel display device and an electron emitting device that can lower the driving voltage, improve the luminous efficiency by using a quantum dot (QD) as a light emitting material The purpose is to provide.

In order to achieve the above object,

A flat panel display device according to an embodiment of the present invention,

A first substrate and a second substrate disposed to face each other at regular intervals;

A plurality of partition walls provided between the first substrate and the second substrate and partitioning a space between the first substrate and the second substrate to form a plurality of cells;

An excitation gas filled in the cells;

A phosphor layer formed on an inner wall of the cells using a quantum dot (QD);

A plurality of first electrodes formed on an inner surface of the first substrate;

A plurality of second electrodes formed on an inner surface of the second substrate in a direction crossing the first electrodes;

A plurality of third electrodes formed on the first electrodes; And

A first electron acceleration layer formed between the first electrode and the third electrode to emit a first electron beam that excites the excitation gas into the cell as a voltage is applied to the first electrode and the third electrode; It is provided.

On the other hand, the electron emission device according to another embodiment of the present invention,

A first substrate and a second substrate disposed to face each other;

A cathode electrode formed on the first substrate;

An electron emission source formed to be electrically connected to a cathode electrode formed on the substrate;

An anode electrode formed on the second substrate; And

And a fluorescent layer which emits light by electrons emitted from the electron emission source and is formed using a quantum dot (QD).

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

According to the present invention, the phosphor layer 115 used in the flat panel display device and the electron emission device may use a quantum dot (QD). In conventional solid-state light emitting materials, energy bands are formed because atoms are concentrated, and when energy is received from the outside, excited electrons are stabilized from a conduction band to a balance band, so that light of the gap is increased. Will emit light. However, when quantum dots are used, there is no interference of atoms, and when energy is received from the outside, excited electrons are stabilized at the atomic energy level and emit light. In this case, theoretical quantum efficiency can be up to 100%, and excitation can be performed at low voltage, thereby improving efficiency, and printing process is possible, which is advantageous for large size.

The quantum dot is composed of a core, a shell, and an organic film structure covering the core and the shell. Preferably the core is CdSe, the shell is ZnS and the organic film is trioctylphosphine oxide.

3 schematically illustrates an embodiment of a quantum dot used as a light emitting material in the flat panel display device of the present invention. The core is CdSe, the shell is ZnS, and the organic film shows trioctylphosphine oxide. The photoluminescent (PL) properties of quantum dots receive energy near 400 nm and give out energy near 580 nm. At this time, the efficiency of both may be close to 100%. Therefore, the quantum dot can be used as a light emitting material in flat panel display devices such as EDD and FED. Such quantum dots may be formed in a single layer or may be formed in multiple layers, but in general, the quantum dots may be formed in a single layer.

4 is a partial cross-sectional view schematically illustrating a flat panel display device having a direct current counter discharge structure according to an embodiment of the present invention. Referring to FIG. 4, the first substrate 110, which is the lower substrate, and the second substrate 120, which is the upper substrate, are disposed to face each other at regular intervals. Here, the first substrate 110 and the second substrate 120 may be made of a transparent glass substrate. In addition, a space between the first substrate 110 and the second substrate 120 is partitioned between the first substrate 110 and the second substrate 120 to form a plurality of cells 114. A number of barrier ribs 113 are provided to prevent electrical and optical crosstalk between cells 114. Phosphor layers 115 of red (R), green (G), and blue (B) are respectively coated on the inner walls of the cells 114. The phosphor layer 115 uses a quantum dot (QD) according to the present invention. The cells 114 are generally filled with an excitation gas including xenon (Xe). Hereinafter, the excitation gas referred to in the present invention refers to a gas that is excited by external energy such as an electron beam to generate ultraviolet rays. On the other hand, the excitation gas of the present invention can also act as a discharge gas.

The first electrode 131 is formed for each cell 114 on the upper surface of the first substrate 110, and the second electrode 132 is formed on the lower surface of the second substrate 120. It is formed every cell 114 in the direction which intersects. In this case, the first electrode 131 and the second electrode 132 become a cathode electrode and an anode electrode, respectively. The second electrode 132 may be made of a transparent conductive material such as indium tin oxide (ITO) to transmit visible light. In addition, a dielectric layer (not shown) may be further formed on the second electrode 132.

An electron accelerating layer 140 is formed on an upper surface of the first electrode 131, and a third electrode 133 that is a grid electrode is formed on an upper surface of the electron acceleration layer 140. It is. The electron acceleration layer 140 may be any material capable of accelerating electrons to generate an electron beam, preferably made of oxidized porous silicon. In this case, the oxidized porous silicon may be oxidized porous polysilicon or oxidized porous amorphous silicon.

When a predetermined voltage is applied to the first electrode 131 and the third electrode 133, the electron acceleration layer 140 accelerates electrons introduced from the first electrode 131 to the third electrode 133. The electron beam (E-beam) is emitted into the cell 114 through the through. The electron beam emitted into the cell 114 excites the excitation gas, and the excited excitation gas is stabilized to generate ultraviolet rays. The ultraviolet rays excite the phosphor layer 115 to generate visible light, and the visible light is emitted toward the second substrate 120 to form an image.

The electron beam is preferably larger than the energy required to excite the excitation gas and less than the energy required to ionize the excitation gas. Accordingly, a voltage is applied to the first electrode 131 and the third electrode 133 so that the electron beam may have optimized electron energy capable of exciting the excitation gas.

FIG. 5 schematically shows an energy level of xenon (Xe) that is an ultraviolet generating source. Referring to FIG. 5, it can be seen that energy of 12.13 eV is required to ionize xenon (Xe), and energy of 8.28 eV or more is required to excite xenon (Xe). Specifically, in order to excite xenon (Xe) in 1S ₅ , 1S ₄ , and 1S ₂ states, energy of 8.28 eV, 8.45 eV, and 9.57 eV is required. This excited xenon (Xe ^* ) is stabilized to generate an ultraviolet light of approximately 147nm. Then, the excited state (excited state) of xenon (Xe ^*) and the ground state (ground state) of xenon (Xe) When a crash excimer (eximer) xenon (Xe ₂ ^*) there is generated, such an excimer xenon (Xe ₂ ^*) When this is stabilized, ultraviolet rays of approximately 173 nm are generated.

Accordingly, in the present invention, the electron beam emitted into the cell 114 by the electron acceleration layer 140 may have an energy of about 8.28 eV to 12.13 eV to excite xenon (Xe). In this case, the electron beam may preferably have an energy of 8.28 eV to 9.57 eV or an energy of 8.28 eV to 8.45 eV. In addition, the electron beam may have an energy of 8.45 eV to 9.57 eV.

6 is a view showing a modification of the flat panel display device according to the present invention. The second electrode 132 ′ is formed in a mesh structure to transmit visible light generated from the cell 114. The third electrode 133 ′ is formed in a mesh structure so that the electrons accelerated by the electron acceleration layer 140 can be easily released into the cell 114.

In the above, the case where the first substrate 110 becomes the lower substrate and the second substrate 120 becomes the upper substrate has been described. However, in the present embodiment, the first substrate 110 having the electron acceleration layer 140 is formed on the upper substrate. The substrate may be applied, and the second substrate 120 may be applied to the lower substrate.

The flat panel display may further include a plurality of fourth electrodes formed on the second electrodes; And a second electron acceleration layer formed between the second electrode and the fourth electrode to emit a second electron beam that excites the excitation gas into the cell as a voltage is applied to the second electrode and the fourth electrode. It may be further provided.

According to another embodiment of the present invention, an electron emitting device using a quantum dot as a light emitting material of a phosphor is provided.

7 schematically shows an electron emitting device having a triode structure among various electron emitting devices according to the present invention. The electron emission device illustrated in FIG. 7 includes an upper plate 201 and a lower plate 202, and the upper plate includes an upper electrode 280, an anode electrode 280 disposed on the lower surface 291 of the upper substrate, and the anode. The phosphor layer 270 disposed on the lower surface 281 of the electrode is provided. The phosphor layer 270 uses a quantum dot (QD) as described above.

The lower plate 202 has a lower surface substrate 210 disposed in parallel with the upper substrate 290 at predetermined intervals to have an inner space, and a cathode electrode disposed in a stripe shape on the lower substrate 210. 220, a gate electrode 240 arranged in a stripe shape to intersect the cathode electrode 220, an insulator layer 230 disposed between the gate electrode 240 and the cathode electrode 220, and the insulator layer ( 230 and an electron emission source hole 265 formed in a portion of the gate electrode 240 and the electron emission source hole 265 are disposed in the electricity is supplied to the cathode electrode 120 and lower than the gate electrode 240 And an electron emission source 260 disposed therein. Detailed description of the electron emission source 260 is the same as described above, and thus will be omitted.

The upper plate 201 and the lower plate 202 are maintained in a vacuum at a pressure lower than atmospheric pressure, and the spacer 295 supports the pressure between the upper plate and the lower plate generated by the vacuum and partitions the light emitting space 310. It is disposed between the upper plate and the lower plate.

The anode electrode 280 applies a high voltage necessary for accelerating the electrons emitted from the electron emission source 260 to allow the electrons to collide with the phosphor layer 270 made of quantum dots at high speed, and visible light by the electrons. Emits a back.

The gate electrode 240 is responsible for easily emitting electrons from the electron emission source 260, and the insulator layer 230 partitions the electron emission source hole 269 and the electrons. It serves to insulate the emission source 260 and the gate electrode 240.

The quantum dot is composed of a core, a shell, and an organic film structure covering the core and the shell. Preferably the core is CdSe, the shell is ZnS and the organic film is trioctylphosphine oxide.

In the electron emission device, the electron emission source 260 may be formed of a carbon-based material, oxidized porous silicon (Metal-Insulator-Metal), or Surface Conduction Electron Emitting Display (SED). It is preferably made of material or porous silicone.

Although the preferred embodiment according to the present invention has been described above, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

As described above, the plasma display panel using the conventional solid-state light emitting materials require a relatively high voltage and have low efficiency, whereas in the present invention, the electron beam emitted from the electron acceleration layer excites the excitation gas. Only one image can be formed. Therefore, the flat panel display device and the electron emitting device according to the present invention can lower the driving voltage and improve the luminous efficiency by using quantum dots without energy interference between atoms as the light emitting material.

Claims (12)

A first substrate and a second substrate disposed to face each other at regular intervals; A plurality of partition walls provided between the first substrate and the second substrate and partitioning a space between the first substrate and the second substrate to form a plurality of cells; An excitation gas filled in the cells; A phosphor layer formed on an inner wall of the cells using a quantum dot (QD); A plurality of first electrodes formed on an inner surface of the first substrate; A plurality of second electrodes formed on an inner surface of the second substrate in a direction crossing the first electrodes; A plurality of third electrodes formed on the first electrodes; And A first electron acceleration layer formed between the first electrode and the third electrode, the first electron acceleration layer emitting a first electron beam that excites the excitation gas into the cell as a voltage is applied to the first electrode and the third electrode; The quantum dot (QD) comprises a core and a shell, and an organic layer is formed to cover the core and the shell, the core is CdSe, the shell is ZnS, and the organic layer is trioctylphosphine oxide. oxide). delete delete The method of claim 1, And the first electron beam has an energy greater than the energy required to excite the excitation gas and less than the energy required to ionize the excitation gas. The method of claim 1, And the first electron acceleration layer is made of oxidized porous silicon. The method of claim 1, And a dielectric layer is formed on the second electrode. The method of claim 1, And the xenon (Xe) is the excitation gas. The method of claim 1, And the first electron beam has an energy of 8.28 eV to 12.13 eV. A first substrate and a second substrate disposed to face each other; A cathode electrode formed on the first substrate; An electron emission source formed to be electrically connected to a cathode electrode formed on the substrate; An anode electrode formed on the second substrate; And And a fluorescent layer which emits light by electrons emitted from the electron emission source and is formed using a quantum dot (QD), wherein the quantum dot (QD) is composed of a core and a shell and covers the core and the shell. An organic film is formed, the core is CdSe, the shell is ZnS, and the organic film is trioctylphosphine oxide. delete delete The method of claim 9, The electron emission source is an electron emission device, characterized in that made of carbon-based material, oxidized porous silicon (Metal-Insulator-Metal), or Surface Conduction Electron Emitting Display (SED).

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