KR100719563B1 - Light emitting device using electron emission and flat display apparatus using the same - Google Patents

Abstract

Disclosure of Invention An object of the present invention is to provide a novel electron emitting light emitting device capable of lowering driving voltage and improving luminous efficiency and a flat panel display device having the same. It is also an object of the present invention to provide an electron emitting light emitting device having a novel structure capable of forming a nano gap while having reproducibility and reliability. To this end, in the present invention, the first electrode; A second electrode disposed at a predetermined distance from the first electrode; A nanogap formation film disposed between the first electrode and the second electrode to maintain a gap; A substrate disposed above the gap between the first electrode and the second electrode; A third electrode disposed on the substrate; And an electron emission light emitting device including a phosphor formed adjacent to the third electrode, and a flat panel display device using the same.

Description

Light emitting device using electron emission and flat display apparatus using the same

1 is a view schematically showing the configuration of a conventional SCE type electron emission light emitting device.

FIG. 2 is an enlarged view of part II of FIG. 1. FIG.

Figure 3 is a perspective view showing the configuration of an electron emitting light emitting device according to an embodiment of the present invention.

4 is a sectional view seen from the IV direction of FIG.

5 is an enlarged view of a portion V of FIG. 4.

Figure 6 is a perspective view showing the configuration of an electron emitting light emitting device according to another embodiment of the present invention.

7 is a view showing an example of a display apparatus using an electron emission light emitting device according to the present invention.

8 is a cross-sectional view taken along the line VIII-VIII of FIG. 7.

<Explanation of symbols for main parts of drawing>

10: First Panel 11: First Board

12: third electrode 13: phosphor layer

20: second panel 21: second substrate

22: gate electrode 23: cathode electrode

24, 24 ': electron emission source 30, 30': electron emission light emitting element

31: first electrode 32: nanogap forming film

33: second electrode 700: flat panel display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device using electron emission and a flat panel display device using the same. More particularly, the present invention relates to an electron emitting light emitting device having a low driving voltage and a high luminous efficiency. And a flat panel display device using the same.

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. 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 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. In such a 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.

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, in the conventional plasma display panel and the flat lamp, energy that is high enough to ionize the discharge gas is required, so that the driving voltage is large and the luminous efficiency is low.

On the other hand, light emitting devices using electron emission include a method using a hot cathode and a cold cathode as an electron emission source. Examples of electron-emitting light emitting devices using a cold cathode include Field Emitter Array (FEA), Surface Conduction Emitter (SCE), Metal-Insulator-Metal (MIM), Metal-Insulator-Semiconductor (MIS), and BSE (Ballistic electron Surface Emitting) type and the like are known.

Among these, the SCE type electron emission light emitting devices are self-luminous displays such as FED, Cathode-Ray Tube (CRT) and Plasma Display Panel (PDP). Since the basic driving principle is the same as that of the CRT, the gradation ratio is higher than that of the PDP, which enables more natural color expression. And the response speed, which is considered to be a disadvantage of LCD, can be realized at the CRT level, so there is no afterimage even in a fast movement such as a sports program. In addition, even when implemented with a large screen of 40 inches or more, the thickness is so thin that it is incomparable with the CRT, and the overall power consumption is attracting attention as a next-generation display.

FIG. 1 is a view showing a schematic configuration of an electron emitting light emitting device constituting a conventional SCE disclosed in U.S. Patent Publication No. 2002/0028285, and FIG. 2 is an enlarged view of part II of FIG. .

As shown in FIG. 1, an electron emission light emitting device constituting the conventional SCE includes a first panel 10 and a second panel 20 arranged at predetermined intervals. The first panel 10 may include a first substrate 11 made of a transparent substrate, a phosphor layer 12 formed on one surface of the first substrate 11, and a protective layer covering the surface of the phosphor layer 12 ( 13) and an anode electrode (not shown) integrally formed with the phosphor layer 12. The second panel 20 includes a cathode electrode 23, a gate electrode 22, the cathode electrode 23, and the second substrate 21, which are disposed to face each other on the second substrate 21. An electron emission source 24 disposed between the gate electrodes 22.

As shown in FIGS. 1 and 2, when a negative voltage is applied to the cathode electrode 23 and a positive voltage is applied to the gate electrode 22, the gate electrode 22 is formed on the cathode electrode 23. Electrons are emitted in the () direction. The emitted electrons propagate in the direction of the anode electrode by the electric field generated by the high (+) voltage applied to the anode electrode, and collide with the phosphor layer 12 provided integrally with the anode electrode to generate visible light.

The conventional electron emission light emitting device having the structure as described above forms a nano-sized gap between the cathode electrode and the gate electrode, and allows electrons to be emitted using the electron tunneling effect therebetween. However, in the related art, a process of forming a nano-sized gap has been made in such a manner that an arbitrary crack is formed by flowing a current through a thin film. However, these methods have problems with repeatability or reliability, and there has been a need to develop new structures that are easy to form nanogaps. In addition, there is a need to develop a new structure of the electron emitting light emitting device having a new structure that can maximize the luminance at low voltage in terms of luminous efficiency compared to the conventional electron emitting light emitting device.

The present invention was developed to solve the above problems, and an object of the present invention is to provide a novel electron emission light emitting device capable of lowering the driving voltage and improving the luminous efficiency and a flat panel display device having the same. . It is also an object of the present invention to provide an electron emitting light emitting device having a novel structure capable of forming a nano gap while having reproducibility and reliability.

An object of the present invention as described above, the first electrode; A second electrode disposed at a predetermined distance from the first electrode; A nanogap formation film disposed between the first electrode and the second electrode to maintain a gap; A substrate disposed above the gap between the first electrode and the second electrode; A third electrode disposed on the substrate; And an electron emission light emitting device comprising a phosphor formed adjacent to the third electrode.

Here, the substrate is disposed in a direction substantially horizontal to the interval formed by the first electrode and the second electrode on the upper side of the second electrode, or the substrate is on the upper side of the plane on which the first electrode and the second electrode is disposed In the first electrode and the second electrode may be disposed in a direction substantially perpendicular to the gap formed.

Here, the space formed by the first electrode and the substrate may be maintained in a vacuum, and the phosphor may be a phosphor that is excited by accelerated electrons to generate visible light. In this case, the phosphor is a phosphor for red light containing SrTiO ₃ : Pr, Y ₂ O ₃ : Eu, Y ₂ O ₃ S: Eu, or Zn (Ga, Al) ₂ O ₄ : Mn, Y ₃ ( Al, Ga) ₅ O ₁₂ : Tb, Y ₂ SiO ₅ : Tb, green phosphor containing ZnS: Cu, Al and the like, Y ₂ SiO ₅ : Ce, ZnGa ₂ O ₄ , ZnS: Ag, Cl and the like It is preferable that it is fluorescent substance chosen from CL type fluorescent substance, such as a blue light fluorescent substance to contain.

Alternatively, the space formed by the first electrode and the substrate may be filled with excitation gas, and the phosphor may be a phosphor that is excited by accelerated electrons and excited by ultraviolet light emitted from the excitation gas to generate visible light. have. In this case, the excitation gas includes xenon (Xe), nitrogen (N ₂ ), deuterium (D ₂ ), carbon dioxide (CO ₂ ), hydrogen (H ₂ ), carbon monoxide (CO), krypton (Kr), and air. It is preferred to include a gas selected from the group to be. The phosphor may be a phosphor for red light such as Y (V, P) O ₄ : Eu ⁺ ₃ , a phosphor for green light such as Zn ₂ SiO ₄ : Mn, YBO ₃ : Tb, or BaMgAl ₁₀ O ₁₇ : Eu. It is preferable that it is fluorescent substance selected from PL type fluorescent substance containing blue light fluorescent substance, such as these.

Here, the interval between the first electrode and the second electrode is 1nm or more and 100nm or less, the first electrode is made of silicon, the second electrode is made of silicon or metal, the nanogap forming film is SiO ₂ It is preferable to be made of.

On the other hand, the object of the present invention as described above, the first electrode; A second electrode disposed at a predetermined distance from the first electrode; A nanogap formation film disposed between the first electrode and the second electrode to maintain a gap; A substrate disposed above the gap between the first electrode and the second electrode; A third electrode disposed on the substrate; And an electron emission light emitting device including a phosphor formed adjacent to the third electrode, and a light emitting device installed in front of the electron emission light emitting device to control light supplied from the electron emission light emitting device to implement an image. It is achieved by providing a flat panel display device having a display panel that includes. Here, the light emitting device may be a liquid crystal.

Hereinafter, with reference to the accompanying drawings will be described in detail a specific embodiment of the present invention.

FIG. 3 is a perspective view schematically showing the configuration of an embodiment of an electron emission light emitting device according to the present invention. FIG. 4 is a cross-sectional view taken from the IV direction of FIG. 3, and FIG. 5 is a part V of FIG. 4. An enlarged view of is shown.

As shown in FIGS. 3 and 4, the electron emission light emitting device 30 according to the present invention includes a first electrode 31, a second electrode 33, a nano gap forming film 32, and a substrate. (11), the third electrode 12 and the phosphor layer 13 are included.

The first electrode 31 may be made of a plate member. The second electrode 33 is disposed at a predetermined distance from the first electrode 31. The nanogap formation film 32 is formed to have a thickness of about 1 nm to 100 nm, and is disposed between the first electrode 31 and the second electrode 33 so that a gap between the two electrodes is about 1 nm to 100 nm. To function.

The substrate 11 is disposed above the gap between the first electrode 31 and the second electrode 33, and is substantially parallel to the first electrode 31 to form a predetermined space. . The third electrode 12 is disposed on the substrate 11, and the phosphor layer 13 is formed at least partially on the surface of the third electrode 12 or is formed adjacent to the third electrode 12. .

The first electrode 31 to the third electrode 12 may be made of any material as long as the material has electrical conductivity. More preferably, in order to facilitate the manufacturing process, the nanogap forming film 32 is made of SiO ₂ , the first electrode 31 is made of silicon (Si), and the second electrode 33 is formed. More preferably it is made of silver silicon or metal. The silicon oxide film (SiO ₂ ) used as a material of the nanogap forming film 32 has an etching selectivity to hydrofluoric acid (HF) in relation to silicon. For this reason, when forming a nano-sized gap between the first electrode 31 and the second electrode 33, the first electrode 31 or the second electrode 33 is etched using hydrofluoric acid (HF). It is easy to form.

The electron emitting light emitting device having the above configuration can be operated as follows.

First, it can be operated in a manner similar to the conventional field emission device (FED). That is, as shown in FIG. 4, a negative voltage is applied to the first electrode 31 and a positive voltage is applied to the second electrode 33. As shown in FIG. 5, the electron tunneling phenomenon occurs in the nano-sized gap between the first electrode 31 to which the negative voltage is applied and the second electrode 33 to which the positive voltage is applied, as shown in FIG. 5. The electrons are emitted by In this case, a positive voltage higher than the positive voltage applied to the second electrode 33 is applied to the third electrode 12 to move electrons toward the third electrode 12. Electrons moving toward the third electrode 12 are accelerated by the third electrode 12 and excite the phosphor layer 13 attached to the surface of the third electrode 12 to generate visible light. .

In order to use this method, the phosphor layer 13 may include red phosphors including SrTiO ₃ : Pr, Y ₂ O ₃ : Eu, Y ₂ O ₃ S: Eu, or Zn (Ga, Al) ₂ O _4. : Mn, Y ₃ (Al, Ga) ₅ O ₁₂ : Tb, Y ₂ SiO ₅ : Tb, green phosphor containing ZnS: Cu, Al, etc., Y ₂ SiO ₅ : Ce, ZnGa ₂ O ₄ , ZnS It should be made of a phosphor selected from CL (Cathode Luminescence) phosphors such as blue light phosphors containing Ag, Cl, and the like. The colors should be arranged appropriately so as to realize the image by forming pixels.

In addition, in order to use this method, the space 35 formed by the first electrode 31 and the substrate 11 must be maintained at a high vacuum of 10 ⁻⁷ Torr or more.

Alternatively, when the excitation gas is filled in the space formed by the first electrode 31 and the substrate 11 and the electrons emitted from the first electrode 31 excite the excitation gas to emit ultraviolet rays. Ultraviolet rays excite the phosphor layer 13 to generate visible light.

In order to use this method, the phosphor layer 13 may be a phosphor for red light such as Y (V, P) O ₄ : Eu ⁺ ₃ , or a phosphor for green light such as Zn ₂ SiO ₄ : Mn, YBO ₃ : Tb, or the like. , BaMgAl ₁₀ O ₁₇ : Eu and the like should be made of a phosphor selected from PL (PhotoLuminescence) -type phosphor containing a blue light phosphor.

In addition, the excitation gas is a group containing xenon (Xe), nitrogen (N ₂ ), deuterium (D ₂ ), carbon dioxide (CO ₂ ), hydrogen (H ₂ ), carbon monoxide (CO), krypton (Kr), air Containing a gas selected from is excited by the electron is suitable for emitting ultraviolet light.

6 is a perspective view schematically showing the configuration of an electron emission light emitting device according to another embodiment of the present invention.

The structure of the electron emission light emitting device according to the present invention is not limited to that shown in FIG. That is, as shown in FIG. 6, in the electron emission light emitting device 30 ′ according to the present invention, an arrangement direction of the first electrode 31 and the second electrode 33 is substantially perpendicular to the substrate 11. It may be arranged as. Even in this case, electrons emitted from the nanogap formed by the first electrode 31 and the second electrode 33 are accelerated by the third electrode 12 formed on the substrate 11 to excite the phosphor layer 13. And generate visible light.

On the other hand, the electron emission light emitting device 30 having the configuration as described above may be used as a surface light source having a predetermined area. In particular, the electron emission light emitting device according to the present invention may be used as a surface light source and used as a back light unit (BLU) of a liquid crystal display (LCD).

FIG. 7 is a perspective view showing the configuration of a flat panel display device in which the electron emission light emitting device according to the present invention functions as a backlight unit, and FIG. 8 is a partial cross-sectional view taken along the line VIII-VIII of FIG. 7. 7 and 8, the same terms as the above-described terms such as a substrate, a first electrode, a second electrode, and the like are used, but are not the same as the aforementioned members, but used in the LCD described as an example. Reference to the member to be distinguished is clearly distinguished by the description of the member number.

As shown in FIG. 7, the flat panel display device according to the present invention includes a liquid crystal display panel 700 and a backlight unit for supplying light to the liquid crystal display panel 700 as a light emitting display panel. A flexible printed circuit board 720 for transmitting an image signal is attached to the liquid crystal display panel 700, and includes a spacer for maintaining a distance between the liquid crystal display panel 700 and a backlight unit disposed behind the liquid crystal display panel 700. 730 is disposed.

The backlight unit is an electron emission light emitting device 30 according to the present invention described above, is supplied with power through a connecting cable 104, and emits visible light (V) through a second substrate in front of the electron emission light emitting device. As a result, the emitted visible light V is supplied to the liquid crystal display panel 700.

With reference to FIG. 8, the structure and operation principle of a liquid crystal display device are demonstrated.

The electron emission light emitting device 30 shown in FIG. 8 may be the same electron emission light emitting device as the electron emission light emitting device 30 shown in FIG. 3. That is, the electron emission light emitting device 30 of the present invention is formed by arranging the substrate 11 and the first electrode 31 at predetermined intervals while forming the predetermined space 35. Since the configuration of the substrate 11 and the first electrode 31 and the members provided thereon is the same as the above description while explaining the configuration of the electron emission light emitting device 30 according to the present invention, a description thereof will be omitted. In the electron emission light emitting device 30 according to the present invention, electrons are emitted from the first electrode 31 by an electric field formed between the first electrode 31 and the second electrode 33, and thus the third electrode 12. Visible light (V) is generated while hitting the phosphor layer 13 formed on the substrate. The generated visible light V travels toward the front liquid crystal display panel 700.

Meanwhile, the liquid crystal display panel 700 includes a first substrate 505, a buffer layer 510 is formed on the first substrate 505, and a semiconductor layer 580 is formed on the buffer layer 510. It is formed into a pattern. A first insulating layer 520 is formed on the semiconductor layer 580, and a gate electrode 590 is formed in a predetermined pattern on the first insulating layer 520, and a second insulating layer is formed on the gate electrode 590. Layer 530 is formed. After the second insulating layer 530 is formed, the first insulating layer 520 and the second insulating layer 530 are etched by a process such as dry etching to expose a portion of the semiconductor layer 580. The source electrode 570 and the drain electrode 610 are formed in a predetermined region including the exposed portion. After the source electrode 570 and the drain electrode 610 are formed, a third insulating layer 540 is formed, and a planarization layer 550 is formed on the third insulating layer 540. The first electrode 620 is formed on the planarization layer 550 in a predetermined pattern, and the third insulating layer 540 and a portion of the planarization layer 550 are etched to form the drain electrode 610 and the first electrode. A conductive passage of the electrode 620 is formed. The transparent second substrate 680 is manufactured separately from the first substrate 505, and a color filter layer 670 is formed on the lower surface 680a of the second substrate. The second electrode 660 is formed on the bottom surface 670a of the color filter layer 670, and the liquid crystal layer 640 is aligned on the surfaces of the first electrode 620 and the second electrode 660 facing each other. The first alignment layer 630 and the second alignment layer 650 are formed. The first polarization layer 500 is formed on the bottom surface 505a of the first substrate 505, and the second polarization layer 690 is formed on the top surface 680b of the second substrate, and the top surface of the second polarization layer is formed. A protective film 695 is formed at 690a. A spacer 560 partitioning the liquid crystal layer 640 is formed between the color filter layer 670 and the planarization layer 550.

The operation principle of the liquid crystal display panel 700 will be described in brief with reference to the first electrode 620 and an external signal controlled by the gate electrode 590, the source electrode 570, and the drain electrode 610. A potential difference is formed between the second electrodes 660, the arrangement of the liquid crystal layer 640 is determined by the potential difference, and the visible light supplied from the backlight unit 100 according to the arrangement of the liquid crystal layer 640. Light ray V is shielded or passed through. The passed light becomes colored as it passes through the color filter layer 670 to implement an image.

Although FIG. 8 illustrates a liquid crystal display panel (particularly, a TFT-LCD), the display panel constituting the flat panel display device of the present invention is not limited thereto. In addition, as the light emitting device, various liquid crystal display panels may be used. A light emitting display panel can be applied.

A flat panel display device having the above-described electron emitting device as a backlight unit may improve the brightness of the image of the display device and increase the lifespan as the brightness and lifetime of the backlight unit are improved.

As described above, according to the present invention, there is provided a new type of electron emitting light emitting device capable of displaying an image by electron emission. In addition, the electron emission light emitting device can display images on a different principle by using phosphor layers having different compositions depending on whether the internal space is kept in vacuum or the excitation gas is filled in the space.

Further, by forming a gap between the first electrode and the second electrode from which electrons are emitted by a nanogap forming film made of SiO 2, an electron emitting light emitting device having a new structure that can easily form a nanogap is provided.

It can be operated in such a way that the excitation gas is filled into the internal space of the electron emitting light emitting device according to the present invention, and the excitation gas is excited by electrons to generate ultraviolet rays, and then the phosphors generate visible light by the ultraviolet rays. In the case of the plasma display panel, a plasma discharge is generated to generate ultraviolet rays, and the display device can produce a display device having excellent energy efficiency compared to a method of generating visible rays by exciting the phosphor layer with the ultraviolet rays.

On the other hand, the present invention has been described with reference to the embodiment shown in the drawings, but this is only exemplary, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. . Therefore, the true technical protection scope of the present invention should be defined by the technical spirit of the appended claims.

Claims (14)

A plate-shaped first electrode; A plurality of second electrodes disposed on the first electrode at predetermined intervals from the first electrode; A nanogap formation film disposed between the first electrode and the second electrode to maintain a gap; A substrate disposed above the gap between the first electrode and the second electrode; A third electrode disposed on the substrate; And And a phosphor formed adjacent to the third electrode, wherein the nanogap formation film has a smaller planar area than the second electrode. The method of claim 1, And the substrate is disposed above the second electrode in a direction parallel to the interval formed by the first electrode and the second electrode. The method of claim 1, And the substrate is disposed in a direction perpendicular to an interval formed by the first electrode and the second electrode on an upper side of a plane on which the first electrode and the second electrode are disposed. The method of claim 1, The space formed by the first electrode and the substrate is maintained in a vacuum, The phosphor is an electron emission light emitting device, characterized in that the phosphor is excited by the accelerated electrons to generate visible light. The method of claim 4, wherein The phosphor is, SrTiO ₃ : Pr, Y ₂ O ₃ : Eu, Y ₂ O ₃ A red light phosphor containing S: Eu or Zn (Ga, Al) ₂ O ₄ : Mn, Y ₃ (Al, Ga) ₅ O ₁₂ : CL type including a phosphor for green light containing Tb, Y ₂ SiO ₅ : Tb, ZnS: Cu, Al, or a phosphor for blue light containing Y ₂ SiO ₅ : Ce, ZnGa ₂ O ₄ , ZnS: Ag, Cl An electron emission light-emitting device, characterized in that the phosphor selected from phosphors. The method of claim 1, The space formed by the first electrode and the substrate is filled with excitation gas, And the phosphor is excited by accelerated electrons and excited by ultraviolet rays emitted from the excitation gas to generate visible light. The method of claim 6, The excitation gas is Contains gases selected from the group consisting of xenon (Xe), nitrogen (N ₂ ), deuterium (D ₂ ), carbon dioxide (CO ₂ ), hydrogen (H ₂ ), carbon monoxide (CO), krypton (Kr), air An electron emission light emitting device, characterized in that. The method of claim 6, The phosphor is, Phosphors for red light such as Y (V, P) O ₄ : Eu ⁺ ₃ , phosphors for green light such as Zn ₂ SiO ₄ : Mn, YBO ₃ : Tb, phosphors for blue light such as BaMgAl ₁₀ O ₁₇ : Eu An electron emission light emitting device, characterized in that the phosphor selected from among the phosphor containing PL. The method of claim 1, And an interval between the first electrode and the second electrode is 1 nm or more and 100 nm or less. The method of claim 1, And the first electrode is an electrode made of silicon. The method of claim 1, And the second electrode is made of silicon or metal. The method of claim 1, The nano-gap forming film is an electron emission light emitting device, characterized in that made of SiO ₂ . A plate-shaped first electrode; A plurality of second electrodes disposed on the first electrode at predetermined intervals from the first electrode; A nanogap formation film disposed between the first electrode and the second electrode to maintain a gap; A substrate disposed above the gap between the first electrode and the second electrode; A third electrode disposed on the substrate; And An electron emission light emitting device including a phosphor formed adjacent to the third electrode, wherein the nanogap formation film has a plane area smaller than that of the second electrode; And a display panel installed in front of the electron emission light emitting device, the display panel including a light emitting device for controlling an image of the light emitted from the electron emission light emitting device to implement an image. The method of claim 13, And the light emitting element is a liquid crystal.

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