KR100623097B1 - Field emission device having triode structure with dual emitters - Google Patents

Abstract

The present invention relates to a field emission device having a three-pole structure of a double emitter, and more particularly, to form an emitter on both the first electrode and the second electrode of the back substrate to eliminate the distinction between the gate and the cathode to eliminate the double electric field. A field emission device having a three-pole structure of double emitters that enables emission.

Field emission apparatus having a three-pole structure of a double emitter of the present invention comprises a front substrate and a rear substrate spaced apart a predetermined interval; An anode electrode present on the front substrate; A phosphor present on the anode; First and second electrodes on the rear substrate and spaced apart from each other by a predetermined interval; And an emitter formed on the first electrode and the second electrode.

Therefore, the field emission device having the three-pole structure of the double emitter of the present invention eliminates the distinction between the gate and the cathode to enable double field emission, thereby providing excellent luminous efficiency, luminance and luminance uniformity, and reducing driving voltage and power consumption. There is an effect that can achieve reduction, long service life and manufacturing cost reduction.

Field emission, Dual emitter, 3-pole structure, backlight

Description

Field emission device having triode structure with dual emitters             

1 is a block diagram showing a field emission device according to the prior art.

2 is a block diagram showing a field emission device according to the present invention.

3 is a cross-sectional view showing the arrangement of the first electrode and the second electrode of the field emission device according to the present invention.

Figure 4 is a plan view of the back substrate of the field emission device according to the present invention.

5 is a current density graph according to the applied field of the present invention and the conventional method.

6 is a block diagram of a field emission device according to another embodiment of the present invention.

7 is a block diagram of a field emission device according to another embodiment of the present invention.

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

100: back substrate 105: first electrode

110: second electrode 115: emitter

117: insulating film 119: insulating layer

200: front substrate 205: anode electrode

210: phosphor 300: spacer

305: sealing material 400: DC inverter

402: AC inverter

The present invention relates to a field emission device having a three-pole structure of a double emitter, and more particularly, to form an emitter on both the first electrode and the second electrode of the back substrate to eliminate the distinction between the gate and the cathode to eliminate the double electric field. A field emission device having a three-pole structure of double emitters that enables emission.

Compared to Cathode Ray Tube (CRT), which has been the dominant type of display, research on flat panel display, a next-generation display device that can be made thinner and thinner, is being actively conducted. The flat panel display includes a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), and the like. Although the plasma display panel and the field emission display emit light by themselves, the liquid crystal display does not emit light by itself and thus requires a backlight (BLU: Backlihgt Unit).

Cold Cathode Fluorescent Lamp (CCFL) type backlight, which is currently used most, is not suitable for large-area display because there is a problem of low luminance uniformity and difficulty in achieving high brightness because the light source is located on the side. In order to solve this problem, a direct type using a cold cathode fluorescent tube has been developed.

Recently, plasma type backlights and field emission type backlights that use plasma display panels and field emission display-related technologies as backlight devices for liquid crystal displays, rather than display devices, have been developed.

Plasma type backlight is a method of causing a discharge through the electrodes formed on the upper plate and the lower plate as disclosed in Korean Patent Laid-Open Publication No. 2002-12096, and excites and emits phosphors from the plasma generated at this time. However, the plasma type backlight has a problem of low discharge efficiency and high heat.

Field emission devices, such as field emission backlights, field emission flat lamps (FEFLs), and field emission displays, are a means of emitting accelerated electrons that excite phosphors, and are pointed cold instead of the hot cathodes used in conventional cathode ray tubes. Use a cathode. That is, by concentrating the high field on the emitter constituting the cold cathode, electrons are emitted by the quantum mechanical tunnel effect. US Patent No. 3,970,887 to Donald O. Smith et al. Discloses a structure in which a silicon (Si) micro tip is formed on a semiconductor substrate and an electron is emitted by applying an electric field to the tip through a gate electrode. Due to the large work function of the material used for the micro tip, there is a problem in that the gate voltage for electron emission must be considerably high and the micro tip is easily damaged.

Therefore, the diamond film has been spotlighted as an emitter, and researches on carbon nanotubes (CNT) that emit electrons even at an electric field about 1/10 lower than the field for emitting electrons of diamond films have been actively conducted. .

However, field emitters have to achieve a wide range of light emission area, high brightness, long lifetime and process simplification for any emitter to be used for practical applications.

Conventional field emission devices have a two-pole or three-pole structure. In the bipolar structure, a high voltage is applied between an anode electrode and a cathode electrode to extract electrons from a field emission material, and electrons excite and emit phosphors. The bipolar structure has a low manufacturing cost, is easy to manufacture and has a large light emitting area, but has a high driving voltage, low luminance stability, and low light emitting efficiency.

Korean Patent Publication No. 2000-74609, US Patent No. 5,773,834, Korean Patent Publication No. 2001-84384, and Korean Patent Publication No. 2004-44101 disclose a field emission device having a three-pole structure. In the three-pole structure, an auxiliary electrode, called a gate electrode, is spaced apart from the cathode electrode by several tens of nanometers (nm) to several millimeters (mm) in order to emit electrons from the field emitter. Make sure The electrons thus emitted were formed to form a high voltage between the anode electrode and the cathode electrode to excite and emit the phosphor on the anode electrode. However, in the three-pole structure, the driving voltage can be greatly reduced and high luminance can be obtained. However, the manufacturing cost is relatively high, manufacturing time is long, and light emitting area is reduced.

A side gate type field emission device disclosed in Korean Patent Laid-Open Publication No. 2004-44101 is shown in FIG. 1. Referring to FIG. 1, a cathode electrode 10 is formed on a surface of a rear substrate 5, an emitter 20 made of carbon nanotubes is positioned on an upper surface of the cathode electrode 10, and the cathode There is a gate electrode 25 spaced apart from the electrode 10 by a predetermined interval and in contact with the back substrate 5 through the insulating layer 15. It is composed of a phosphor layer 30, an anode electrode 35 composed of indium tin oxide (ITO), a front substrate 40, and the like facing the rear substrate 5.

The conventional three-pole structure field emission device including the side gate method does not emit electrons from the gate electrode 25, so luminance unevenness occurs, and electrons are generated only from the emitter 20 formed on the upper surface of the cathode electrode 10. Since the emitter 20 is heavily loaded, the emitter 20 has a lot of loads, thereby shortening the lifespan and causing low luminance.

Accordingly, the present invention is to solve the above-mentioned disadvantages and problems of the prior art, by forming an emitter on both the first electrode and the second electrode corresponding to the conventional gate electrode and the cathode, in fact, of the gate electrode and the cathode By eliminating the distinction, double field emission is possible, so that the emission efficiency, brightness improvement, brightness uniformity improvement, manufacturing cost, driving voltage and power consumption can be achieved. It is an object of the present invention to provide a device.

The object of the present invention is a front substrate and a rear substrate spaced apart a predetermined interval; An anode electrode present on the front substrate; A phosphor present on the anode electrode; First and second electrodes on the rear substrate and spaced apart from each other by a predetermined interval; And an emitter formed on the first electrode and the second electrode, the field emission device having a three-pole structure of a double emitter.

Details of the above object and technical configuration of the present invention and the effects thereof according to the present invention will be more clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

<Example 1>

2 is a block diagram of a field emission device having a three-pole structure of a double emitter according to the present invention.

In the field emission device of the present invention, the first electrode 105 and the second electrode 110 are present on the rear substrate 100 and the emitter is disposed on the upper surfaces of the first electrode 105 and the second electrode 110. 115 is located. By forming the emitter 115 on both the first electrode 105 and the second electrode 110, the structure of the conventional gate electrode and the cathode electrode is virtually eliminated. The second electrode 110 may be a gate or a cathode electrode. In this way, an increase in the light emitting area, an increase in the luminous efficiency, uniform light emission, high brightness and long life can be achieved.

The back substrate 100 may be made of glass, alumina (Al ₂ O ₃ ), quartz, plastic, silicon (Si) substrate, and the like, and more preferably, a glass substrate.

The first electrode 105 and the second electrode 110 are silver (Ag), chromium (Cr), copper (Cu), aluminum (Al), nickel (Ni), zinc (Zn), titanium (Ti), Metals such as platinum (Pt), tungsten (W) and ITO and alloys thereof are possible, and printing by screen printing is suitable, but the method of sintering metal powder or sputtering, vacuum deposition and chemical vapor deposition (CVD: It may also be formed using a thin film deposition method such as Chemical Vapor Deposition.

The emitter 115 may be carbon nanotube, diamond, DLC (Diamond Like Carbon), fullerene (Fulleren), palladium oxide (PdO) and the like, but carbon nanotubes that can emit electrons at a relatively low voltage are more preferable. Do.

The transparent electrode 205 and the phosphor 210 are formed on the front substrate 200, and there is a spacer 300 to maintain a distance between the front substrate 200 and the rear substrate 100. It is sealed by the sealing material 305 such as glass), and the inside thereof is maintained at a high vacuum of about 10 ⁻⁷ torr.

The front substrate 200 may be glass, quartz, plastic, or the like, and a glass substrate is more preferable. In addition, when the back substrate 100 and the front substrate 200 are both used as plastic substrates, they may be used as backlights of flexible liquid crystal displays.

The transparent electrode 205 may be formed by depositing, coating or printing a transparent conductive material such as ITO on the front substrate 200. The phosphor 210 is preferably a white phosphor such as an oxide or a sulfide obtained by mixing red, green, and blue phosphors at a predetermined ratio, and may be formed by a screen printing method.

3 is a cross-sectional view illustrating an arrangement of the first electrode 105 and the second electrode 110. As shown in FIG. 3A, the first electrode 105 and the second electrode 110 are equally spaced apart from each other. As shown in FIG. 3B, the first electrode 105 and the second electrode 110 may be formed in pairs to lower the driving voltage. As shown in FIG. 2, an insulating insulating layer 117 may be formed between the first electrode 105 and the second electrode 110 to prevent the two electrodes from shorting.

Figure 4 is a plan view of the back substrate of the field emission device having a three-pole structure of a double emitter according to the present invention. As shown in FIG. 4, the first electrode 105 and the second electrode 110 are alternately formed in a rake shape, and voltages of different polarities are applied to the first electrode 105 and the second electrode 110. By alternately applying the electrons, electrons are emitted from the emitters 115 positioned on the respective electrodes. Since electrons are emitted from both electrodes in this manner, as shown in FIG. 5, a larger current density can be obtained under the same electric field as compared with the conventional side gate tripolar structure field emission device. Of course, it is also possible to use one of the first electrode 105 or the second electrode 110 as a gate electrode.

The field emitter having a three-pole structure with a double emitter of the present invention is a direct current (DC) inverter (Inverter, 400), a first electrode for generating a power applied to the anode electrode 205 on the front substrate for its driving And an AC inverter 402 for generating power applied to the second electrode.

<Example 2>

6 and 7 are structural diagrams showing another embodiment of the field emission device having a three-pole structure of a double emitter according to the present invention.

6 and 7, in the field emission device according to Embodiment 2 of the present invention, a first electrode 105 and a second electrode 110 are present on the back substrate 100 and the first electrode is provided. The emitter 115 is positioned on the top surface of the 105 and the second electrode 110. The anode electrode 205 and the phosphor 210 are formed on the front substrate 200, and there is a spacer 300 that maintains a gap between the front substrate 200 and the back substrate 100. It is enclosed and its inside is designed to maintain a high vacuum of about 10 ^-7 torr.

In the field emission device of FIG. 6, the insulating layer 119 is formed under the first electrode 105 serving as the gate electrode to improve the low efficiency of the conventional side gate type tripolar structure. Also in 105), the emission area is widened by allowing electrons to be emitted.

In the field emission device illustrated in FIG. 7, the area of the second electrode 110 is increased by increasing the area of the second electrode 110 than the first electrode 105 having the insulating layer 119. It has a structure in which luminous efficiency is increased.

Although the present invention has been shown and described with reference to the preferred embodiments as described above, it is not limited to the above embodiments and those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

Therefore, the field emission device having the triple emitter structure of the double emitter of the present invention has a double emitter structure with no distinction between the gate and the cathode, so that the process is similar to the bipolar structure and sequentially emits electrons from the emitters of the two electrodes. Because of this, the light emitting area is widened, the light emitting efficiency, luminance and luminance uniformity are excellent, long life can be secured, and it is most preferable as the next generation BLU structure as a structure suitable for mass production.

Claims (7)

In the field emission device, A front substrate and a rear substrate spaced apart from each other by a predetermined interval; An anode electrode present on the front substrate; A phosphor present on the anode electrode; First and second electrodes on the rear substrate and spaced apart from each other by a predetermined interval; And Emitters formed on the first and second electrodes Field emission device having a three-pole structure of a double emitter, characterized in that comprising a. The method of claim 1, The field emission device having a three-pole structure of a double emitter, further comprising an insulating layer under the first electrode. The method of claim 1, And a short preventing isolation insulating film between the first electrode and the second electrode. The method according to any one of claims 1 to 3, The front substrate and the back substrate is a field emission device having a three-pole structure of a double emitter, characterized in that made of glass or quartz. The method according to any one of claims 1 to 3, And wherein the anode electrode is made of a transparent electrode such as ITO. The method according to any one of claims 1 to 3, The emitter is a field emission device having a three-pole structure of a double emitter, characterized in that made of any one of carbon nanotubes, diamond, DLC, fullerene or palladium oxide. The method according to any one of claims 1 to 3, And the first electrode and the second electrode are made of any one of silver, chromium, aluminum, and tungsten.

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