KR20010081496A - Field emission device using metal mesh grid and fabrication method thereof and method for focusing emitted electrons - Google Patents

Abstract

PURPOSE: A field emission device adopting metal meshing grid and method for fabricating thereof and focusing method of emission electron are provided to improve display color purity although using high spacer by varying a voltage inputted to a metal mesh grid. CONSTITUTION: A field emission device comprises a transparent front substrate(15) and a back substrate(11), arranges a spacer(18) between the front substrate(15) and the back substrate(11), and maintain regular interval. On the back substrate(11) sequentially comprises cathodes(12) on a stripe, an insulated layer(13), and gates(14) on the stripe across the cathode(12). The insulated layer(13) on the cathode(12) forms holes(13). A micro tip(12) is comprised on the cathode exposed by the holes(13). The gates(14) comprise an opening corresponding to the holes(13). On the opposite face of the inter side of the front substrate(15) is formed with anodes(16) on the stripe across the cathode(12). On the anodes(16) comprises a phosphor. A metal mesh grid(19) controls electrons emitted from the micro tip(12) between the gate and the anode.

Description

Field emission device using metal mesh grid and fabrication method according to field emission device employing metal mesh grid and method for focusing emitted electrons}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission device, and more particularly, to a field emission device having a mesh grid which prevents damage during arcing generation and helps focusing of emission electrons. Method of manufacture The present invention relates to a method for focusing emitted electrons.

1 is a cross-sectional view schematically showing the structure of a conventional field emission device. As shown in the drawing, the conventional field emission device basically has a transparent front substrate 5 and a back substrate 1 and has a structure in which a spacer 8 is disposed therebetween to maintain a constant gap. On the back substrate 1, the cathodes 2 on the stripe are formed, the insulating layer 3 is formed thereon, and the gates 4 are formed on the stripe in a direction crossing the cathode 2 thereon. Holes 3 'are formed in the insulating layer 3 on the cathode 2, and microtips 2' for electron emission are formed on the cathode 2 exposed by the holes 3 ', Openings 4 'corresponding to the holes 3' are formed in the gates 4 so that electrons emitted from the microtips 2 'can be emitted toward the anode. In addition, the anodes 6 are formed on the inner facing surface of the front substrate 5 on a stripe in a direction crossing the cathode 2, and the phosphors 7 are coated on the anodes 6, so that the microtips ( Electrons emitted from 2 ') and traveling toward the anode 6 hit the phosphor 7 to emit light.

As such, arc discharge may occur in the internal space between the two substrates while the electrons are emitted. The cause of such arcing is not precisely determined, but is caused by a discharge phenomenon caused by a large amount of gas being instantaneously ionized by outgassing or the like generated inside a panel. It is estimated. Arcing occurs even at high vacuum when FEA's are manufactured and applied at an anode voltage of 1 KV or more during chamber testing or sealed FED testing. Observation of the surface of the FEA's with an optical microscope after arcing shows that damage due to arcing occurs mainly at the gate edge. It is estimated that since the gate edge part is sharpened, a high electirc field is applied and arcing occurs in this part. Arcing causes an electrical short between the anode and the gate, which results in high voltage on the gate, damaging the gate oxide and the resistive layer. . This possibility arises more severely as the anode voltage increases and eventually becomes more arcing when an anode voltage of 1 kV or more is applied, so that the cathode and anode are combined with spacers as in conventional field emission devices. In a simple structure, it is impossible to obtain a high brightness FED that operates stably at high voltage.

SUMMARY OF THE INVENTION The present invention has been made to improve the above problems, and includes a field emission device employing a metal mesh grid for controlling emission electrons so as to prevent generation of arc discharge due to high voltage application, a method of manufacturing the same, and focusing of the emission electrons. The purpose is to provide a method.

1 is a cross-sectional view schematically showing the structure of a conventional field emission device;

2 is a cross-sectional view schematically showing the structure of a field emission device according to the present invention;

FIG. 3A is a plan view illustrating the phosphor and the spacer holder formed on the front substrate in the structure of the field emission device of FIG. 2;

3b is a schematic view of a spacer mounted to a spacer holder in the structure of the field emission device of FIG. 2;

FIG. 3C is a plan view showing a metal mesh grid fixed with a spacer to a front substrate in the structure of the field emission device of FIG. 2; FIG.

3D is a perspective view illustrating a state in which a phosphor formed on a front substrate, a spacer, and a mesh grid are combined in the structure of the field emission device of FIG. 2;

4A and 4B are diagrams showing the arrangement relationship between the phosphor and the mesh grid in the coupling structure of FIG.

5 is a view showing an application position of a conductive paste for electrically connecting a metal mesh grid and an electrode terminal in the bonding structure of FIG. 3D;

FIG. 6 is a diagram illustrating a trace of emission electrons as a result of simulating conditions in which color purity is improved in the field emission device of FIG.

7 is a graph showing the amount of anode current according to the voltage applied to the mesh grid in the field emission device of FIG.

8A and 8B are diagrams showing the trajectories of the emission electron beams that appear when 80 V is applied to the mesh grid when the distance between the mesh grid and the gate (d3-t _mesh ) in the field emission device of FIG. 2 is 140 μm and 340 μm, respectively. .

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

1. Back board 2. Cathode

3. Insulation layer 3 '. hall

4. Gate 4 '. Opening

5. Front substrate 6. Anode

7. Phosphor 8. Spacer

11.Rear substrate 12.Negative electrode

13. Insulation layer 13 '. hall

14. Gate 14 '. Opening

15. Front Board 16. Anode

17. Phosphor 18. Spacer

19. Metal mesh grid 19 '. Opening (dot)

19a. Incision 20. First spacer holder

21. Second spacer holder 22. Mesh grid electrode terminal

23. Glass holder 24. Conductive paste

In order to achieve the above object, the field emission device employing the metal mesh grid according to the present invention includes: a front substrate and a rear substrate disposed to face each other at regular intervals; Cathodes formed in a stripe shape on the rear substrate; An insulating layer having holes on the rear substrate and the cathodes to expose the cathode at regular regular intervals; Gates formed on the insulating layer in a stripe direction crossing the cathodes and having openings corresponding to the holes; Microtips formed on the cathode exposed by the holes; Anodes disposed on the front substrate on a stripe in a direction crossing the cathodes; And a phosphor coated on the anodes, the field emission device comprising: emitting from the microtips in regions corresponding to intersections of the anodes and the cathodes in a space between the gate and the anodes; And a metal mesh grid having openings formed therein for allowing the electrons to pass therethrough.

In the present invention, the metal mesh grid is supported by a rod-shaped spacer formed in the shape of concavities and convexities in a direction parallel to the cathode, and is formed to have a cutout portion in which protrusions in the concavities and convexities of the spacers are inserted, and the gate of the metal mesh grid. It is preferable that an insulating film is coated on the opposite surface.

In addition, in the present invention, the metal mesh grid is formed of stainless steel, the spacer is formed of glass, both edges of the front substrate spacer holders having grooves to each of the bar-shaped spacer edge is coupled; And applying a voltage to the metal mesh grid at a glass holder for supporting the metal mesh grid and at an area of the front substrate subsequent to the glass holder at an edge of the four edges of the front substrate where the spacer holder is not formed. It is preferable that the electrode terminal for this is formed.

In addition, the method of manufacturing a field emission device employing a metal mesh grid according to the present invention in order to achieve the above object, the front substrate and the rear substrate disposed to face each other at regular intervals; Cathodes formed in a stripe shape on the rear substrate; An insulating layer having holes on the rear substrate and the cathodes to expose the cathode at regular regular intervals; Gates formed on the insulating layer in a stripe direction crossing the cathodes and having openings corresponding to the holes; Microtips formed on the cathode exposed by the holes; Anodes disposed on the front substrate on a stripe in a direction crossing the cathodes; A phosphor coated on the anodes; And a metal mesh grid having an opening for allowing electrons emitted from the microtips to pass through areas corresponding to intersections of the anodes and the cathodes in a space between the gate and the anodes. A method of fabricating a field emission device, comprising: (a) forming the cathode, insulating layer, gate, and microtips on the back substrate; (B) forming anodes and phosphors on the front substrate, fabricating the metal mesh grid thereon, and fixing the openings so that the openings are aligned with the anodes; And (c) combining and packaging the rear substrate and the front substrate respectively formed in the steps (a) and (b).

In the present invention, in the step (b), each opening of the mesh grid is preferably formed to correspond one-to-one with each phosphor color, and the mesh grid is configured to remove residual stress remaining in the metal mesh grid. Pre-firing step of firing; And inserting the prefired metal mesh grid between two glass substrates larger than the total size of the metal mesh grid and firing at a temperature between 300 ° C and 500 ° C. It is supported by a rod-shaped spacer formed in the shape of concavities and convexities in a direction parallel to the cathode, and is formed to have a cut-out portion into which the protrusions in the concavities and convexities of the spacers are inserted, and in the step (b), It is preferable to further include forming an insulating layer.

In addition, in the present invention, the step (b) includes (b-1) a sub-step of manufacturing the rod-shaped uneven spacers with alumina; (B-2) For attaching a first spacer holder and a second spacer holder having grooves for fixing the spacer to both edges of the front substrate, and the mesh grid and electrode terminals for applying a voltage to the mesh grid, respectively. A sub step of forming a holder; (B-3) sub-aligning the mesh grid with the anodes and bonding the mesh grid to the front substrate; wherein, in the (b-2) sub-step, the first spacer holder is integrally formed, and The two spacer holders are formed individually so that one spacer can be fitted per one, so that the spacers are sandwiched between the grooves of the first spacer holder, and the spacers are aligned with respect to the phosphor, and in step (b-2), When the length of the support portion in contact with the anode side in the uneven spacer d1, the length of the flesh portion in the center d2, the length of the support portion in contact with the cathode is d3, the first spacer holder and the first The depth of the groove in the two spacer holder is formed to d2, the holder is smaller than the electrode terminal of the mesh grid, the area is formed to a height corresponding to d1 + d2, the ( 3) the sub-step, (B -3-1) the sub-step of applying a paste for fixing please insert a projection of said spacer arranged on the positive electrode of the front substrate, the cut-out portion of the metal mesh grid; (B-3-2) sub-aligning the openings of the mesh grid with the anodes before the fixing paste is hardened; (B-3-3) applying a conductive paste to the edge of the mesh grid on the holder and to the side of the holder on the upper surface of the electrode terminal for electrically connecting the mesh grid to the mesh grid electrode terminal; (B-3-4) after the conductive paste is applied, the front substrate is dried at 100 to 250 ° C., and then a firing step is performed at 300 to 450 ° C., preferably.

In addition, the emission electron focusing method of the field emission device employing the metal mesh grid according to the present invention in order to achieve the above object, the front substrate and the rear substrate disposed to face each other at regular intervals; Cathodes formed in a stripe shape on the rear substrate; An insulating layer having holes on the rear substrate and the cathodes to expose the cathode at regular regular intervals; Gates formed on the insulating layer in a stripe direction crossing the cathodes and having openings corresponding to the holes; Microtips formed on the cathode exposed by the holes; Anodes disposed on the front substrate on a stripe in a direction crossing the cathodes; A phosphor coated on the anodes; And a metal mesh grid having openings through which electrons emitted from the microtips pass in regions corresponding to intersections of the anodes and the cathodes in a space between the gate and the anodes. An emission electron focusing method of a field emission device, comprising: (a) applying a voltage of 70 to 120 V to the gate and applying a voltage of 1 KV or more to the anode; (B) finding an optimal focusing condition of the electron beam emitted from the microtip by adjusting the voltage applied to the mesh grid to -100V to 300V; (C) Finding a condition having an optimal color purity while varying the voltage applied to the metal mesh grid, and at the same time changing the distance between the metal mesh grid and the gate (d3-t _mesh ) in consideration of luminance, and displaying the image. and (b) finding a condition in which the color purity and the luminance of the image are optimal.

In the present invention, in the step (c), it is preferable to set the applied voltage of the mesh grid to 0V and to adjust the distance between the mesh grid and the gate (d3-t _mesh ) by 100 μm.

EMBODIMENT OF THE INVENTION The field emission element employing the metal mesh grid which concerns on this invention, its manufacturing method, and the focusing method of an emission electron are demonstrated in detail, referring drawings.

2 is a schematic cross-sectional view of a field emission device employing the arc preventing metal mesh grid according to the present invention. As shown, the field emission device according to the present invention basically has a transparent front substrate 15 and a back substrate 11, like conventional field emission devices, and has a constant gap therebetween by arranging spacers 18 therebetween. On the rear substrate 11, the cathode 12 on the stripe and the insulating layer 13 and the gate 14 on the stripe in the direction crossing the cathode 12 are sequentially provided, but the cathode 12 Holes 13 ′ are formed in the insulating layer 13 on the substrate 13, and micro-tips 12 ′ are provided on the cathode 12 exposed by the holes 13 ′, and the holes 14 are formed in the gate 14. 13 ') corresponding to the openings 14', and the anodes 16 are formed on the inner facing surface of the front substrate 15 on a stripe in a direction crossing the cathode 12. On the 16) has a structure having a phosphor 17. However, it characterized in that it further comprises a metal mesh grid 19 for controlling the electrons emitted from the microtip 12 'between the gate and the anode, the spacer for supporting the metal mesh grid to be fixed at a certain position The layout is also characteristic.

The field emission device having the arc preventing metal mesh grid having such a configuration has openings in units of one color of red, green, blue (R, G, and B) colors, as shown in FIGS. 2 and 4A. By inserting a metal mesh grid having an open array pattern between the gate and the anode, the gate edge is applied even when a voltage of about -100V to 300V is applied. The electric field value at the edge is small to prevent arcing relatively well, and metal mesh before the ion damages the cathode when arcing occurs. By being trapped by the trap and falling into an external ground, mechanical damage caused by arcing and electrical damage in which a part of the anode voltage is applied to the cathode are prevented.

The manufacturing method of the field emission element which has the above structure is as follows.

First, as shown in FIG. 2, the cathode 12 and the field emitter arrays 12 ′ are formed on the rear substrate 11. Field emitter arrays (FEAs) are formed on the rear substrate 11 by forming the micro tips 12 'by an etched tip forming method or a spin't method. Here, FEAs capable of matrix addressing may be used in addition to the above two methods.

Next, a front substrate is formed on which a mesh grid, spacers, and phosphors are formed. It is formed in the following order.

First, as shown in FIG. 3A, a phosphor and a black matrix are formed. After the electrode is patterned on the front plate 15, the phosphor 17 is formed by electrophoretic, screen printing, slurry, or the like. In addition, a black matrix (not shown) is also formed in a conventional manner. The anode pattern also includes a grid electrode 22.

Second, a spacer 18 as shown in FIG. 3B is formed. The spacer is formed on the front plate (anode plate) after the phosphor and black matrix forming process is as follows.

As shown in FIG. 3A, spacer holders 20 and 21 for securing the spacers are formed at both edges of the front substrate 15. The spacer holders 20 and 21 form grooves into which spacers can be fitted. The spacer holders 20 and 21 are made of ordinary glass and have a thickness of about 700 μm. The first spacer holder 20 is formed in one piece, and the second spacer holder 21 is formed in a single piece so as to fit one spacer per one. A spacer made of aluminum is sandwiched between the grooves, and the spacer is aligned with respect to the phosphor 17. The spacer 18 is formed in an uneven shape as shown in FIG. 3B. That is, the spacer 18 is divided into a supporting portion d1 in contact with the anode side, a flesh portion d2 in the center, and a supporting portion d3 in contact with the cathode. As shown in FIG. 3, when d1, d2, and d3 are referred to, the distance d3 value of the supporting portion which will come into contact with the cathode is important as described in the following method of forming the metal mesh grid.

Third, as shown in FIG. 3A, the glass holder 23 and the first and second spacer holders 20 and 21 for attaching the mesh grid 19 and the grid electrode 22, respectively, are attached. Form. If the mesh grid 19 and the grid electrode 22 are directly attached without the holder, the mesh grid should be bent due to the height difference due to the step difference of the spacer (see FIG. 5). To avoid this, the holders 20, 21, 23 are formed as follows.

First, in shape, the area is slightly smaller than the mesh grid electrode 22, and the height is formed at a height corresponding to d1 + d2 when a mesh grid is formed on the spacer. Next, a glass material such as soda lime is used as the material. Next, the depth of the grooves in the first and second spacer holders 20 and 21 is d2 so that the edges of the spacers may fit snugly in the grooves, and the holders 20, 21 and 23 may be attached to the front substrate 15. When pasting, paste using a common adhesive paste (paste).

Fourth, a metal mesh grid as shown in FIG. 3C is formed by the following method. The mesh grid is made of suss or inva steel, which is stainless steel. Inva steel is used as a shadow mask when manufacturing CRTs, and its coefficient of thermal expansion is much smaller than that of general Suss. This is particularly effective in reducing the thermal stress generated during the next firing process. Therefore, Inva steel is used in the manufacture of large-area FEDs. In the manufacture of small FEDs, normal suss strength is also possible.

In addition, as shown in FIG. 4, the opening pattern of the mesh grid is formed in an array of openings 19 ′ having a size of one dot. One phosphor color 17 corresponds to one opening, that is, a mesh dot 19 '. As shown in FIG. 3C, a spacer actually forms a cutout 19a corresponding to the size of the cathode and the portion that supports the anode. The thickness of the mesh grid 19 shall be about 50-100 micrometers.

In addition, as a pretreatment process, there is a possibility that residual stress remains in the metal mesh grid produced in the above process, and if it is simply used, distortion of the metal mesh grid may occur during the next firing process. Therefore, it is subjected to a pre-firing process. That is, the metal mesh grid is sandwiched between two glasses slightly larger than the total size of the metal mesh grid and fired at a temperature between 300 and 500 ° C. In this way, all residual stress remaining in the metal mesh grid disappears, thereby maintaining a flat shape even after the firing process.

Next, Al deposition is performed because the metal mesh grid is oxidized during the firing process. When oxidation occurs in the metal mesh grid, the electrical conductivity and surface properties may change, so Al metal, a very soft material, is coated on both sides of the mesh grid. This step may be omitted.

Fifth, the mesh grid is aligned with the anode and bonded to the front substrate as shown in FIG. 3D. First, an alignment to anode of a mesh grid is performed. A metal mesh grid (A) is formed on the anode 16 of the front substrate through the holder 20, 21, and 23 forming process. 19) and insert the fixing paste. The paste is viscous in its initial state, so that the mesh grid is aligned to the anode. The shape after alignment is shown in FIGS. 4A and 4B. When the mesh grid is fixed to the front substrate by paste after the alignment of the anode and the mesh grid is completed, as shown in FIG. 5, the mesh grid electrode 22 and the mesh grid 19 are electrically connected to each other. In order to apply a conductive paste (Conduting paste) (24). Next, in order to dry the firing and firing paste of the front substrate, after coating the conductive paste, the front substrate is dried at 100 to 250 ° C., and then the firing process is performed at 300 to 450 ° C.

Next, the back substrate 11 on which the microtips (field emitter arrays) are formed and the front substrate 15 on which the mesh grid is aligned are packaged in a conventional manner to obtain an FED.

The FED obtained in this way controls the focusing of the emission electrons. That is, when the field emission device is completed, color purity and brightness are adjusted. The following method is used to adjust the color purity and brightness.

First, a normal voltage is applied to the gate and the anode, and a voltage of approximately 70 to 120 V is applied to the gate, and a voltage of approximately 1 KV or more is applied to the gate.

Next, the voltage of the mesh grid is adjusted to -100V to 300V to find an electron beam focusing condition emitted from an optimal microtip. As a simulation result, as shown in FIG. At a mesh grid voltage of about -30 to -40 V, most electrons are deflected and returned to FEA's, and only electrons that pass nearly the center of each dot pattern of the metal mesh grid are phosphors. As a result, the color purity is improved. According to the visual observations of the actual experiment, the optimal color purity was obtained at the mesh grid voltage of about -10V to 10V.

Next, if the voltage applied to the metal mesh grid is varied as described above, a condition having an optimum color purity may be found, but at the same time, brightness should be considered. As shown in this way the measurement results taking into account the brightness 7, the grid voltage V _grid (grid voltage) positive electrode current corresponding to the I _a (anode current) to look at, the cathode current in accordance with the grid voltage V _grid (grid voltage) I _a It can be seen that the value of (anode current) changes rapidly. As described above, in order to obtain a color purity, when the V _grid is applied at almost 0 V, the value of Ia becomes small, so that desired luminance is difficult to be obtained even at a high voltage of 2 kV. Therefore, the most important factor to be considered in order to obtain both color purity and brightness simultaneously is the distance between the metal mesh grid and the gate of the field emitter arrays (FEAs). d3 (see Figure 3b) -t _mesh (see Figure 5) is important. Where t _mesh is the thickness of the metal mesh grid. As shown in FIG. 8A, the smaller the value of the d3-t _mesh , that is, the distance between the metal mesh grid and the gate, the better the e-beam trajectory of the field emission device. That is, as shown in FIG. 8B, when the distance is about 340 μm, the trajectory of most electrons emitted at an angle of about 30 ° from the vertical direction in the microtip of FEA's does not strike the corresponding phosphor through the mesh grid. In this case, the neighboring phosphors are priced. Therefore, the color purity of the image displayed by the FED is lowered.

Therefore, grid voltage and d3-t _mesh value considering color purity and brightness at the same time are about 0V and about 100μm, respectively.

In addition, when manufacturing the field emission device, it is important to prevent current leakage between the gate and the metal mesh grid. Since the voltage applied to the metal mesh and the gate are different, the shortening of this distance may cause a problem of current leakage due to local distortion of the mesh grid. In order to prevent this, before fabricating the mesh grid and anodes in the fabrication process and bonding the mesh grid to the front substrate, the metal mesh may be formed by using an SiO ₂ thin film or an insulator such as polyimide on the side of the mesh grid toward the gate. By coating the entire surface of the grid, leakage current can be prevented. When using this process, the distance between the metal mesh grid and the gate can be nearly zero. In this case, most of the electrons are directed toward the anode through the metal mesh grid. Therefore, it is possible to increase the anode current, which further increases the brightness.

As described above, a field emission device employing a mesh grid that prevents damage due to arcing and assists focusing of the emission electrons may include gates and anodes. And a metal mesh grid with openings in the spaces between which the electrons emitted from the microtips pass, in areas corresponding to the intersections of the anodes and cathodes, and the position of this metal mesh grid By adjusting it with the rod spacer of, it is possible to apply the high voltage to the anode because there is no damage to the cathode during arcing and the arcing is minimized to obtain a high brightness FED. In addition, since the electron beam focusing is possible by varying the voltage applied to the metal mesh grid, display color purity is improved even when a large spacer is used.

Claims (19)

A front substrate and a rear substrate disposed to face each other at regular intervals; Cathodes formed in a stripe shape on the rear substrate; An insulating layer having holes on the rear substrate and the cathodes to expose the cathode at regular regular intervals; Gates formed on the insulating layer in a stripe direction crossing the cathodes and having openings corresponding to the holes; Microtips formed on the cathode exposed by the holes; Anodes disposed on the front substrate on a stripe in a direction crossing the cathodes; And A field emission device comprising: a phosphor coated on the anodes; And a metal mesh grid having an opening in the space between the gate and the anodes to allow electrons emitted from the microtips to pass through regions corresponding to intersections of the anodes and the cathodes. A field emission device characterized in that. The method of claim 1, The metal mesh grid is supported by a bar-shaped spacer formed in the form of unevenness in a direction parallel to the cathode, the field emission device characterized in that it is formed to have a cut-out portion is inserted into the protrusion of the unevenness of the spacer. The method according to claim 1 or 2, And an insulating film coated on the gate facing surface of the metal mesh grid. The method according to claim 1 or 2, And the metal mesh grid is formed of stainless steel. The method of claim 2, And the spacer is formed of glass. The method of claim 2, A spacer holder having grooves to which the rod-shaped spacer edges are respectively coupled to both edges of the front substrate; and the metal mesh grid is supported at four edges of the front substrate where the spacer holder is not formed. And an electrode terminal for applying a voltage to the metal mesh grid in an area of the front substrate subsequent to the glass holder. A front substrate and a rear substrate disposed to face each other at regular intervals; Cathodes formed in a stripe shape on the rear substrate; An insulating layer having holes on the rear substrate and the cathodes to expose the cathode at regular regular intervals; Gates formed on the insulating layer in a stripe direction crossing the cathodes and having openings corresponding to the holes; Microtips formed on the cathode exposed by the holes; Anodes disposed on the front substrate on a stripe in a direction crossing the cathodes; A phosphor coated on the anodes; And a metal mesh grid having openings through which electrons emitted from the microtips pass in regions corresponding to intersections of the anodes and the cathodes in a space between the gate and the anodes. In the method of manufacturing the field emission device, (A) forming the cathode, insulation layer, gate and microtips on the back substrate; (B) forming anodes and phosphors on the front substrate, fabricating the metal mesh grid thereon, and fixing the openings so that the openings are aligned with the anodes; And (C) packaging by combining the back substrate and the front substrate formed in the steps (A) and (B), respectively; Method for producing a field emission device comprising a. The method of claim 7, wherein In the step (b), each opening of the mesh grid is formed to correspond one-to-one with the color of each phosphor. The method of manufacturing a field emission device according to claim 1, wherein the mesh grid 19 has a thickness of about 50 to 100 μm. ) The method of claim 7, wherein In the step (b), in order to remove the residual stress remaining in the mesh grid, Pre-firing the metal mesh grid; And Sandwiching the prefired metal mesh grid between two glass substrates larger than the full size of the metal mesh grid and firing at a temperature between 300 and 500 ° C .; The method of manufacturing a field emission device further comprising. The method of claim 9, And depositing Al on both sides of the metal mesh grid prior to the firing step. The method of claim 7, wherein The metal mesh grid is supported by a bar-shaped spacer formed in the shape of concave-convex in a direction parallel to the cathode, the manufacturing method of the field emission device, characterized in that it is formed to have a cut-out portion is inserted into the protrusions in the concave-convex of the spacer. The method of claim 7, wherein And (b) forming an insulating layer on the gate facing surface of the metal mesh grid in the step (b). The method of claim 7, wherein the step (b), (B-1) a sub-step of fabricating the rod-shaped uneven spacers with alumina; (B-2) For attaching a first spacer holder and a second spacer holder having grooves for fixing the spacer to both edges of the front substrate, and the mesh grid and electrode terminals for applying a voltage to the mesh grid, respectively. A sub step of forming a holder; (B-3) sub-aligning the mesh grid with the anodes and bonding the mesh grid to the front substrate; Method for producing a field emission device comprising a. The method of claim 13, In the sub-step (b-2), the spacer holder glass is formed (with a thickness of about 700 μm), and the first spacer holder is formed in one piece, and the second spacer holder is formed in one piece, one per piece. And inserting the spacer between grooves of the first spacer holder to align the spacer with respect to the phosphor. The method according to claim 14, wherein in the sub-step (b-2), When the length of the support portion in contact with the anode side of the uneven spacer is d1, the length of the flesh portion in the center is d2, and the length of the support portion in contact with the cathode is d3, the first spacer holder and the second The depth of the groove in the spacer holder is formed by d2 method of manufacturing a field emission device. The method according to claim 14, wherein in the sub-step (b-2), When the length of the support portion in contact with the anode side of the uneven spacer is d1, the length of the flesh portion in the middle is d2, and the length of the support portion in contact with the cathode is d3, the holder is an electrode terminal of the mesh grid. The area is smaller and is formed at a height corresponding to d1 + d2. The method of claim 13, wherein the (b-3) sub-step, (B-3-1) applying a fixing paste after inserting the protrusions of the spacers aligned with the anodes of the front substrate to the cutout of the metal mesh grid; (B-3-2) sub-aligning the openings of the mesh grid with the anodes before the fixing paste is hardened; (B-3-3) applying a conductive paste to the edge of the mesh grid on the holder and to the side of the holder on the upper surface of the electrode terminal for electrically connecting the mesh grid to the mesh grid electrode terminal; (B-3-4) after applying the conductive paste, drying the front substrate at 100 to 250 ° C., and then performing a baking process at 300 to 450 ° C. Method for producing a field emission device comprising a. A front substrate and a rear substrate disposed to face each other at regular intervals; Cathodes formed in a stripe shape on the rear substrate; An insulating layer having holes on the rear substrate and the cathodes to expose the cathode at regular regular intervals; Gates formed on the insulating layer in a stripe direction crossing the cathodes and having openings corresponding to the holes; Microtips formed on the cathode exposed by the holes; Anodes disposed on the front substrate on a stripe in a direction crossing the cathodes; A phosphor coated on the anodes; And a metal mesh grid having openings through which electrons emitted from the microtips pass in regions corresponding to intersections of the anodes and the cathodes in a space between the gate and the anodes. In the emission electron focusing method of the field emission device, (A) applying a voltage of 70 ~ 120V to the gate, and applying a voltage of 1KV or more to the anode; (B) finding an optimal focusing condition of the electron beam emitted from the microtip by adjusting the voltage applied to the mesh grid to -100V to 300V; (C) Finding a condition having an optimal color purity while varying the voltage applied to the metal mesh grid, and at the same time changing the distance between the metal mesh grid and the gate (d3-t _mesh ) in consideration of luminance, and displaying the image. (c) finding a condition in which the color purity and the luminance of the image are optimal; Emission focusing method of a field emission device comprising a. The method of claim 18, In the step (c), the applied voltage of the mesh grid is 0V, and the emission electron focusing method of the field emission device, characterized in that to adjust the distance (d3-t _mesh ) between the mesh grid and the gate 100μm. All dimensions of this claim, i.e. the spacing between the anode and the gate and the mesh grid between gates and applied voltages, must be defined as a whole.