KR20020032208A - Field Emission Display having self focusing gate electrode and manufacturing method thereof - Google Patents

Abstract

PURPOSE: An FED having a structure of a magnetic focusing type gate electrode and a method for fabricating the same are provided to focus an electron beam by changing only an array state of a gate electrode. CONSTITUTION: A buffer layer is formed on an upper portion of on a predetermined substrate such as a glass substrate or a silicon substrate(S1). The buffer layer is formed with a nitride layer or an oxide layer. A cathode electrode of a panel shape is formed on an upper portion of the buffer layer and a cathode hole is formed thereon(S2). A gate insulating layer having a plurality of gate hole is formed on the cathode electrode(S3). The gate insulating layer is formed with a silicon oxide layer or a silicon nitride layer. A gate electrode is formed on gate insulating layer(S4). A micro tip is formed in an inside of the gate hole(S5) by using a vertical deposition method.

Description

Field emission display device having self-focusing gate electrode structure and manufacturing method thereof

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission display device having a self-focusing gate electrode structure and a method of manufacturing the same, and more particularly, to focus an electron beam emitted from an emitter disposed above a field emitter array emitting high current density. Without the installation of a separate focusing electrode, only the arrangement of the gate electrode is changed so that the electron beam can be focused automatically when the panel is actually driven. As a result, the manufacturing process is shortened, low power consumption, and high current with high durability. The present invention relates to a field emission display device having a self-focusing gate electrode structure having a density, and a method of manufacturing the same.

In general, a field emission display device is a device that emits electrons when a strong electric field is applied to a sharp part of a metal material called a micro tip, and generates light when the emitted electrons collide with a fluorescent film of an anode. Because smaller unit pixels are formed in the pixel group of, the operation of the pixel group does not occur even if one or two unit pixels are defective. It is attracting attention as the next generation display device equipped.

Specifically, the field emitter of the thin-film field-emitting device first introduced by CA SPINDT in 1968 sharpens the micro tip for electron emission into a conical shape, and places the gate electrode for applying a voltage to the micro tip very close to several micrometers. Electrons can be emitted from the micro tip even at low voltages of tens of volts.

Accordingly, a voltage of several hundred to several thousand volts (v) is uniformly applied to the anode, and zero or negative tens of volts (v) is applied to the micro tip (cathode electrode), and a positive tens of voltage is applied to the gate electrode. The electrons are released from the micro tip and accelerated to the anode electrode.

However, in the field emission display device having the above-described configuration, the electrons emitted from the tip spread toward the anode with the divergence angle of about 60 degrees, so that the selected pixels do not emit light, but the surrounding pixels emit light, resulting in mixed color and display of clear image quality. Often not.

1 illustrates a plan view of a part of a conventional pixel for focusing electrons emitted and diffused in an emitter region as described above.

Referring to FIG. 1, the micro tip 2 is formed inside the plurality of gate holes 1, and the gate electrode 3 formed on the micro tip 2 has an amount of electrons emitted from the micro tip 2. In order to determine the direction, a focusing electrode 4 of a horizontal structure having a shape surrounding the emitter region is configured to focus electrons.

FIG. 2 is a cross-sectional view illustrating a cross-sectional configuration of a field emitter having an upper surface as shown in FIG. 1. According to FIG. There is a difficulty in the manufacturing process that the A) should be close and the distance (B) between the end of the gate electrode 3 and the end of the focusing electrode 4 should be close, and conversely, the width C of the focusing electrode 4 should be large. This limits the number of emitters per unit area.

Since the current emission performance of the field emission device is directly proportional to the number of emitters, it is difficult to manufacture the field emission device having the high current emission performance using an emitter having such a structure.

Another focusing electrode applied to the field emission device is a vertical focusing electrode having the cross-sectional configuration of FIG. 3.

The structure of the field emission device according to FIG. 3 is mainly composed of a cold cathode chip 201, a substrate 202, a first insulating layer 203, a gate electrode 204, and a cold cathode device 209. The cathode chip 201 is composed of a substrate 202, a first insulating layer 203, a gate electrode 204, and an emitter 205. The cold cathode device 209 is a cold cathode chip 201 and a focusing electrode. 208 and the second insulating layer 207.

In the microcold cathode 206, the emitter 205, the gate electrode 204, and the first insulating layer 203 are located in an open concentric hole of the cold cathode element 209.

The field emission device operates by applying a voltage of -40 V to the focusing electrode 208 and a voltage of 80 V to the gate electrode 204 so that the electron beam emitted from the emitter 205 can be focused. In order to control the voltage, the control voltage is applied to the gate electrode 204.

Since the tip of the emitter 205 is made extremely sharp and the gate electrode 204 is near the tip of the emitter 205, a high electric field is applied to the tip of the emitter 205 to emit electrons. .

Electrons emitted from the plurality of emitters 205 are formed into electron beams focused by the focusing electrode 208.

Since the thickness of the second insulating layer 207 is about 10 to about 100 μm, the capacitance between the focusing electrode 208 and the gate electrode 204 or the substrate 202 can be made sufficiently small. The thickness of the second insulating layer 207 required to control 206 may vary depending on the design of the field emission device but is usually on the order of one half of the cathode radius.

Therefore, since the gate electrode 204, the emitter 205, and the focusing electrode 208 are integrated, the focusing electrode 208 that can focus the electron beam effectively and strongly influence the formation of the electron beam is the cold cathode 206. It can be located close to the device to form a high-precision electric field, thereby forming a high quality electron beam.

The cold cathode device including the vertical focusing electrode has excellent electron beam focusing performance, but the fabrication process of the device is very difficult to form the second insulating layer very thick (10 to several 100 μm), and is precisely aligned on the cold cathode chip and is concentric. Since the formation of the focusing electrode having the structure of is very difficult, there is a disadvantage in that the manufacturing yield is very low.

The present invention is derived to solve the above problems, an object of the present invention is to change the arrangement of the gate electrode without installing a separate focusing electrode to automatically focus the electron beam during the actual driving of the panel. .

Another object of the present invention is to provide a manufacturing method that simplifies the structure and manufacturing process of the field emitter array of the field emission display device.

Another object of the present invention will be described in more detail in the configuration and operation to be described later.

1 is a top view of a field emitter with a conventional focusing electrode.

2 is a cross-sectional view of a field emitter with a conventional horizontal focusing electrode.

3 is a cross-sectional view of a field emitter with a conventional vertical focusing electrode.

4 is a top view of a field emitter with a gate electrode structure in accordance with the present invention.

5 is a conceptual diagram illustrating a process of sequentially applying a scan signal to a self-focusing gate electrode according to the present invention.

Figure 6 is a cross-sectional view for showing the flow of the electron beam according to the present invention.

7 is a flowchart illustrating a process of forming a field emitter array of a field emission display device according to the present invention.

According to the present invention, a field emitter array of a field emission display device in which a plurality of pixels are formed in a matrix form includes: a cathode electrode formed on a predetermined substrate; and formed on the cathode electrode and exposing a portion of the surface of the cathode electrode; A gate insulating layer having a plurality of gate holes, and a micro tip formed on the cathode of the gate hole; And a gate electrode formed on the gate insulating layer and formed so that a predetermined pixel is not electrically connected to adjacent pixels.

Preferably, the pixel is formed spaced apart from the adjacent pixels by a predetermined distance, for example, a distance of 0.1 μm to 20 μm.

The method of manufacturing a field emission display device having a self-focused gate electrode structure according to the present invention includes forming a cathode on a predetermined substrate; and forming a gate insulating layer having a plurality of gate holes on the cathode. Forming a gate electrode on the gate insulating layer such that a predetermined pixel is not adjacent to an adjacent pixel; And forming a micro tip inside the gate hole. Preferably, the pixel is spaced apart from an adjacent pixel by a predetermined distance.

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

FIG. 4 is a diagram showing a preferred embodiment of the present invention. According to FIG. 4, a pixel 17 having a predetermined gate electrode 13 is not formed in an emitter region emitting electrons. The gate electrodes 14 and 15 of both the pixels 18 and 19 adjacent to each other are configured to serve as focusing electrodes.

The cathode electrode is formed to have a panel shape, for example, on a buffer layer formed of a nitride film or an oxide film having a thickness of 1000 to 5000 ~ on a glass substrate or a silicon substrate.

The gate insulating layer is formed by depositing a silicon oxide film on the cathode electrode and patterning the silicon oxide layer to form a plurality of contact holes.

FIG. 5 illustrates sequentially applying a scan signal to a self-focusing gate electrode for driving a field emission display device according to an embodiment of the present invention, wherein the gate electrode receiving the scan signal is applied with a voltage pulse, but does not receive a signal. 0 V is applied.

Therefore, electrons emitted from the pixel to which the voltage is applied to the gate electrode are focused by the electric field of the 0V voltage of the gate electrode of the adjacent pixel without focusing the beam and reach the anode.

FIG. 6 is a cross-sectional view illustrating the flow of an electron beam according to the operation of FIG. 5, wherein voltages are not applied to gate electrodes 14 and 15 adjacent to both sides of a predetermined gate electrode 13 to which a voltage of 100 V is applied. It is well shown that the gate electrodes 14 and 15 adjacent to both sides serve as focusing electrodes so that the focused electron beam reaches the anode 23 as shown in FIG. 6.

As described above, when the gate electrode is formed in a zigzag form to enable the focused action of the emitted electrons, the structure of the field emission display device is simplified, and micromachining of the sub-microlevel can be performed with high precision.

In addition, the structure becomes simpler and finer, which is relatively effective in improving electron emission characteristics, and it is possible to directly place active elements or functional structures on a bed, or to form a resistive layer on a substrate.

7 is a flowchart illustrating a process of forming a field emitter array of a field emission display device according to the present invention.

According to FIG. 7, in the method of manufacturing an emitter array of a field emission display device according to the present invention, a buffer layer is first formed on a predetermined substrate, for example, a glass substrate or a silicon substrate (step S1).

At this time, the buffer layer is preferably for preventing the diffusion of impurities of a predetermined substrate to the cathode electrode, and is formed of a nitride film or an oxide film having a thickness of 1000 ~ 5000Å.

Then, a cathode is formed on the buffer layer in the form of a panel, and a cathode hole, which is defined as a gate hole, is formed on the entire surface (step S2).

Here, the cathode hole is formed in a diameter of about 3 ~ 10 ㎛ by a photolithography process using a separate mask capable of forming a cathode hole.

A gate insulating layer having a plurality of gate holes in communication with the cathode holes is formed on the cathode electrode (step S3).

The gate insulating layer is an insulating layer for preventing excessive current from flowing from the above-described cathode electrode to the gate electrode to be described later. A silicon oxide film, a silicon nitride film, or the like is usually used.

A gate electrode is formed on the gate insulating layer so that a predetermined pixel is not electrically connected to an adjacent pixel (step S4).

As a preferred shape where the pixel is not electrically connected to an adjacent pixel, a gate electrode formed in a zigzag form between the emitter portions of each pixel is used.

Then, a micro tip is formed in the above-described gate hole by the vertical evaporation method (step S5).

The field emitter array of the field emission display device formed through the above steps does not include a separate process step for forming the focusing electrode, which simplifies the process and reduces the probability of a process defect according to the simplified process. Can increase.

As mentioned above, although preferred embodiments of the present invention have been described in detail, those of ordinary skill in the art may vary the present invention without departing from the spirit and scope of the present invention. Or it can be seen that it can be changed.

As described above, the field emitter of the field emission display device according to the present invention does not need a separate focusing electrode and changes only the arrangement of the gate electrodes so that the electron beam is focused automatically when the panel is actually driven. There is an effect of obtaining image quality.

In addition, since a manufacturing process for installing a separate focusing electrode is not required, a manufacturing yield can be increased, and a large number of field emitters are required in a pixel because a separate focusing electrode does not require a region. It enables low power consumption, durable uniform and high emission current, and active driving of field emission display elements.

Claims (5)

A field emitter array of a field emission display device in which a plurality of pixels are formed in a matrix shape, A cathode electrode formed on a predetermined substrate; A gate insulating layer formed on the cathode electrode and having a plurality of gate holes exposing a part surface of the cathode electrode; A micro tip formed on the cathode electrode in the gate hole; And And a gate electrode formed on the gate insulating layer, the gate electrode being formed so that a predetermined pixel is not electrically connected to adjacent pixels. The method of claim 1, And the pixel is formed to be spaced apart from the adjacent pixels by a predetermined distance. The method of claim 2, The predetermined distance is a field emission display device having a self-focusing gate electrode structure, characterized in that the distance of 0.1 ㎛ to 20 ㎛. Forming a cathode on a predetermined substrate; Forming a gate insulating layer having a plurality of gate holes in communication with the cathode holes on the cathode electrodes; Forming a self-focusing gate electrode on the gate insulating layer such that a predetermined pixel is not electrically connected to an adjacent pixel; And forming a micro tip in the gate hole, wherein the field emission display device has a self-focusing gate electrode structure. The method of claim 4, wherein And the pixel is formed to be spaced apart from an adjacent pixel by a predetermined distance.