KR100378422B1 - The FED and the manufacturing method of FED which is equipped with inverted ladder-type focusing electrode - Google Patents

Abstract

A field emission display device having an inverted trapezoidal focusing electrode according to the present invention includes: a cold cathode as an electron emission unit, a gate electrode for controlling an electron emission amount of the cold cathode, and a lower substrate including a focusing electrode for focusing the emitted electrons; An upper substrate on which an anode, a red, blue, green phosphor formed on the anode, and a black matrix formed on the boundary of the phosphor are formed; In a field emission display device having a spacer supporting between an upper substrate and a lower substrate, the focusing electrode has an inverted trapezoidal shape and is formed next to the gate electrode.

In addition, the method for manufacturing a field emission display device having an inverted trapezoidal focusing electrode according to the present invention includes forming a protective layer of a photosensitive material on an emitter and a gate electrode; Forming a seed layer for the plating process on the protective layer; Forming a focusing electrode pattern with a photosensitive material on the seed layer; Forming a trapezoidal focusing electrode on the focusing electrode pattern through a plating process; Removing the focusing electrode pattern; Nicking the seed layer and removing the protective layer.

As described above, the present invention improves the focusing speed of electrons emitted from the emitter by forming the gate electrode of or above the gate electrode of the field emission display device having a tripolar structure, thereby improving color purity.

Description

Field emission-type display device having an inverted trapezoidal focusing electrode and a method of manufacturing the same {The FED and the manufacturing method of FED which is equipped with inverted ladder-type focusing electrode}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of focused electrodes used in field emission display devices, and in particular, to form an inverted trapezoidal shape with an inverted trapezoidal focus electrode which improves the focusing speed of electrons emitted from the emitter. An emission display device and a method of manufacturing the same.

In the field emission type display device, an electron beam is emitted by an electric field applied to an emitter end, and electrons emitted from the emitter end do not accurately reach a corresponding phosphor and emit a color to cause color spread. In order for the electron beam emitted from the emitter to reach the corresponding phosphor accurately, it is necessary to change the path of the electron beam emitted at the initial velocity. In particular, there is a tendency to increase the distance between the screen portion and the emitter portion in order to secure high voltage reliability, in which case the beam spreading phenomenon is further intensified.

In addition, in the case of the micro tip type device which is the most representative example of the field emission type display device, since the emitting surface of the tip is formed into a spherical surface and electrons are emitted by the electric field formed by the gate electrode, the electron beam reaches only the corresponding phosphor. Rather than reaching other phosphors, the phenomenon of beam spreading is easily observed.

Therefore, a focusing electrode is required to focus these electron beams so that the electron beam emitted from the emitter reaches only the phosphor corresponding to the emitter.

1 is a view showing the shape of a conventional typical focusing electrode.

Referring to FIG. 1, a negative voltage is applied to the focusing electrode 110 to push and focus an electron beam emitted from the emitter 120. However, in this structure, the insulating film II 140 is formed on the gate electrode 130 and the focusing electrode 110 is formed thereon to be patterned. However, it is difficult and complicated to form a high focusing electrode in order to bring sufficient focusing effect. There is a disadvantage to go through the process.

2 is a view showing the shape of a conventional improved focusing electrode.

Referring to Fig. 2, this focusing electrode is a structure proposed by Spint (C.A. Spindt) as a patent (USP 5,235,244) modified with respect to the shape of the focusing electrode of Fig. 1.

This structure eliminates the focusing electrode formed on the existing insulating layer II, and instead, the insulating layer II 210 is formed high on the gate electrode 220.

When electrons are initially emitted from the emitter 230, electron charging occurs on the surface of the insulating layer II 210, and the electron beam emitted by the charged negative charge is pushed and focused. In this case, the insulating layer II 210 is proposed to have a thickness of about 2 μm, which is limited to the case where the secondary layer has a secondary electron emission coefficient of 1 or less due to the electrons emitted from the emitter 230. Although this structure is relatively simple compared to the structure of the focusing electrode in FIG. 1, the focusing electrode operates automatically without application of an external voltage. However, the process of forming an insulating layer having a height of 2 μm after the emitter is complicated. There is a disadvantage that the degree of focusing is fixed according to the structure of the device because it is a structure using the electrons charged in the insulating layer (II).

3 is a view showing a rectangular focusing electrode formed next to a conventional gate electrode.

Referring to FIG. 3, the focusing electrode 320 is positioned next to the gate electrode 310, and is a patent (USP5, 528, 103) proposed by Condescent.

This patent is a structure that focuses electrons emitted from the emitter 330 by forming a focusing electrode 320 that is at least 10 times the thickness of the gate electrode at a position close to the gate electrode 310 to enable electron beam focusing.

4 is a diagram illustrating an equipotential line of a rectangular focusing electrode in a field emission display device in which a rectangular focusing electrode is formed next to a gate focusing electrode of the related art.

The equipotential lines of FIG. 4 may first have local potential deformation due to the cathode near the gate electrode 410 and equipotential line changes due to the screen voltage at the top of the focusing electrode, but ignore the influence of the cathode and the screen voltage to center the focusing electrode. Only the general tendency is exaggerated.

In the case of the micro tip, there are a large number between the rectangular focusing electrodes 420, but the size of the micro tip is negligible because the size of the micro tip will be almost the same as the equipotential line with the gate electrode 510 on the gate electrode 410. In the case of the upper part of the electrode, as the voltage of the anode electrode 430 is higher (~ thousand volts) (for reference, the voltage of the gate electrode is several tens of volts), the equipotential lines tend to be pushed toward the focusing electrode wall and the gate direction, but overall It could not be expressed in detail and only showed a general tendency.

It can be seen that the voltage of the anode electrode 430 is much higher than the voltage of the gate electrode 410 so that the equipotential surface is parallel to the focusing electrode 420.

However, the rectangular focusing electrode also has a disadvantage in that the electron beam spreading phenomenon occurs when the height of the spacer is increased for high voltage stability of the field emission device.

SUMMARY OF THE INVENTION The present invention has been made to improve the above-mentioned problems. In order to prevent color purity degradation due to spreading of an electron beam that may occur when the height of a spacer is increased for high voltage stability of a field emission display device, It is an object of the present invention to provide a field emission display device having a trapezoidal focusing electrode having an inverted trapezoidal shape to improve the focusing speed of electrons emitted from an emitter, and a method of manufacturing the same.

1 is a view showing the shape of a conventional typical focusing electrode.

2 shows a form of a conventional improved focusing electrode.

3 is a view showing a rectangular focusing electrode formed next to a conventional gate electrode.

4 is a diagram showing an equipotential line of a rectangular focusing electrode in a field emission display device in which a rectangular focusing electrode is formed next to a conventional gate focusing electrode.

FIG. 5 is a view showing that an inverted trapezoidal focusing electrode is formed next to a gate electrode in a field emission display device having an inverted trapezoidal focusing electrode according to the present invention; FIG.

6 is a diagram showing an equipotential line of an inverted trapezoid focusing electrode in a field emission display device having an inverted trapezoid focusing electrode according to the present invention;

7 is a view showing a method of manufacturing a field emission display device having an inverted trapezoidal focusing electrode according to the present invention.

Explanation of symbols on the main parts of the drawings

510: focusing electrode 520: gate electrode

530: lower substrate 540: cathode electrode

550: resistance layer 560: emitter

570: insulation layer

In order to achieve the above object, the field emission display device having an inverted trapezoidal focusing electrode according to the present invention includes a cold cathode serving as an electron emitting unit, a gate electrode controlling an electron emission amount of the cold cathode, and focusing the emitted electrons. A lower substrate on which a focusing electrode is formed; An upper substrate having an anode, a red, blue, green phosphor formed on the anode, and a black matrix formed on the boundary of the phosphor; In the field emission display device having a spacer for supporting between the upper substrate and the lower substrate,

The focusing electrode is characterized in that its shape is trapezoidal in shape.

Here, the focusing electrode is characterized in that the point formed next to the gate electrode.

In addition, a method for manufacturing a field emission display device having an inverted trapezoidal focusing electrode according to the present invention for achieving the above object comprises the steps of forming a protective layer of a photosensitive material on the emitter and the gate electrode;

Forming a seed layer for the plating process on the protective layer;

Forming a focusing electrode pattern on the seed layer using a photosensitive material;

Forming an in trapezoidal focusing electrode on the focusing electrode pattern through a plating process;

Removing the focusing electrode pattern;

Characterizing the seed layer and removing the protective layer is characterized in that.

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

FIG. 5 is a diagram showing the formation of the trapezoidal focusing electrode next to the gate electrode in the field emission display device having the trapezoidal focusing electrode according to the present invention.

Referring to FIG. 5, a cathode electrode 540, a resistance layer 550, an emitter 560, an insulating layer 570, a focusing electrode 510, and a gate electrode 520 are formed on the lower substrate 530. The trapezoidal focusing electrode 510 may be formed on the side or the top of the gate electrode 520, and may adjust the degree of focusing of the beam by varying the −voltage on the focusing electrode 510.

In this case, as the focusing electrode 510, a metal, an insulator, a high resistance material, and a combination of these materials may be used.

6 is a diagram showing an equipotential line of an inverted trapezoid focusing electrode in a field emission display device having an inverted trapezoid focusing electrode according to the present invention.

The equipotential lines of FIG. 6 may first have local potential deformation due to the cathode near the gate electrode 610 and equipotential line changes due to the screen voltage above the focusing electrode, but ignore the influence of the cathode and the screen voltage and center the focusing electrode. Only the general tendency is exaggerated.

In the case of the micro tip, there are a large number between the inverted trapezoidal focusing electrodes 620, but the size of the micro tip is almost the same as that of the equipotential line with the gate electrode 610 at a few μm above the gate, and thus, the anode electrode 630 is ignored. The higher the voltage (~ thousand volts) of (the gate electrode has a voltage of several tens of volts), the equipotential line tends to be pushed toward the focusing electrode wall and the gate direction, but it cannot be expressed in detail. It was.

Under the above assumption, it can be seen that an equipotential line is formed in a trapezoidal shape as shown in FIG. 6 to perform a better role of the focusing electrode than the conventional rectangular focusing electrode as shown in FIG. 4.

7 is a view showing a method of manufacturing a field emission display device having an inverted trapezoidal focusing electrode according to the present invention.

Referring to FIG. 7, firstly, (a) of FIG. 7 is a bottom plate of a field emission display device having a typical three-pole structure. The cathode electrode 750, the resistive layer 760, the emitter 710, and the insulation are disposed on the substrate 740. The layer 730 and the gate electrode 720 do not form a focusing electrode.

In this state, since the emitter 710 is exposed, the protective layer 770 is formed of a photosensitive material on the emitter 710 and the gate electrode 720 as shown in FIG. 7B to prevent damage to the emitter. do.

At this time, since the photosensitive material is damaged when the plating seed layer is formed, the protective layer 770 has a thickness of about 5 μm or more to facilitate the process of removing the photosensitive material. It is good. Too thick photosensitive materials can interfere with the formation of the desired photosensitive material pattern upon focusing electrode pattern formation and tend to be damaged and difficult to remove when forming metal processes of too thin photosensitive material.

After forming the protective layer 770 of the photosensitive material, a seed layer 780 for the plating process is formed as shown in FIG.

The seed layer 780 uses a metal such as titanium (Ti), niobium (Nb), etc. having good adhesion as an adhesion layer in order to increase adhesion with the gate insulating layer, and copper (Cu), gold (Au), and silver ( A metal thin film having good electrical conductivity such as Ag) is used as a seed layer.

In this step, the seed layer 780 is entirely coated on the passivation layer 770, thereby reducing the plating rate due to the distance from the voltage applying part of the jig during the plating process, thereby enabling uniform plating.

After forming the seed layer 780, a focusing electrode pattern 790 is formed of a photosensitive material.

At this time, the focusing electrode pattern 790 of the photosensitive material blocks all portions except where the focusing electrode is formed to be plated on the exposed part, and the focusing electrode pattern of the photosensitive material 790), the height and shape of the photosensitive material become an important factor. An inverted trapezoidal mold for forming a focusing electrode having an inverted trapezoidal shape having a better focusing speed than a conventional rectangular shape is formed.

A plating process is performed as shown in FIG. 7E to form an inverted trapezoidal focus electrode 791.

In the case of the plating process, there is a limitation in the uniformity of the plating bath, so it is preferable to manage the portion having the highest plating height smaller than the photosensitive material height.

After the plating process for forming the focusing electrode 791 is completed, the focusing electrode pattern 790 of the photosensitive material is removed as shown in FIG. 7F, and the plating seed layer 780 is removed as shown in FIG. 7G. After etching, the protective layer 770 of the photosensitive material is removed as shown in FIG. 7H, thereby completing the lower plate of the field emission display device having an inverted trapezoidal focusing electrode.

As described above, the field emission type display device having an inverted trapezoidal focusing electrode and a method of manufacturing the same according to the present invention are formed by forming on or next to the gate electrode of a tripolar field emission display device. It improved the speed of collection and the color purity accordingly.

Claims (3)

A lower substrate having a cold cathode serving as an electron emitting unit, a gate electrode controlling an electron emission amount of the cold cathode, and a focusing electrode for focusing the emitted electrons; An upper substrate having an anode, a red, blue, green phosphor formed on the anode, and a black matrix formed on the boundary of the phosphor; In the field emission display device having a spacer for supporting between the upper substrate and the lower substrate, The focusing electrode has an inverted trapezoidal shape and is formed next to a gate electrode. delete Forming a protective layer of photosensitive material over the emitter and the gate electrode; Forming a seed layer for the plating process on the protective layer; Forming a focusing electrode pattern on the seed layer using a photosensitive material; Forming an in trapezoidal focusing electrode on the focusing electrode pattern through a plating process; Removing the focusing electrode pattern; And etching the seed layer and removing the protective layer.