KR20020029566A - Getter of Field Emission Display and Method of Fabricating the same - Google Patents

Abstract

An object of the present invention is to provide a getter of a field emission display device capable of maintaining internal vacuum in a high vacuum state.

The field emission display device of the present invention has a gas in a field emission device having a lower substrate, a plurality of cathode electrodes formed on the lower substrate, and a plurality of field emission arrays which are display areas formed by a plurality of gate electrodes intersecting the cathode electrodes. And a getter for adsorbing is located in the field emission array region.

As a result, the getter according to the present invention is formed in the center of the long groove located on the lower substrate between the cathode electrodes in the active region, thereby keeping the inside of the panel in a high vacuum state. In addition, since it is possible to form in any space except the spacer, the surface area of the getter is significantly larger than the getter mounted in the exhaust tube in the prior art, so that the gas can be absorbed outgassing (maximum) to improve the life, electric field It is possible to prevent the vacuum from dropping due to the discharge. In addition, by installing the getter below, the wear of the emitter tip may be reduced due to the collision of electrons and gases from the cathode electrode. Further, the FED according to the present invention is advantageous in large area since the exhaust port is not formed, so that the field emission array and the effective display screen area can be made larger.

Description

Getter of Field Emission Display and Method of Fabrication thereof {Getter of Field Emission Display and Method of Fabricating the same}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission display, and more particularly to a getter of a field emission display for maintaining an internal vacuum in a high vacuum state.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes (CRTs). Such flat panel displays include a liquid crystal display (LCD), a field emission display (hereinafter referred to as "FED"), a plasma display panel (PDP), and the like. The FED uses a cold cathode, which concentrates a high field on a sharp cathode (emitter) and emits electrons by a quantum mechanical tunnel effect, which excites the phosphor by an electron beam like a cathode ray tube, thereby emitting an image. Will be displayed.

Referring to FIG. 1, there is shown a FED having an upper glass substrate 2 on which an anode electrode 4 is formed, and a lower glass substrate 12 on which a field emission array 32 is formed. A spacer 10 is formed between the upper glass substrate 2 and the lower glass substrate 12 to provide a field emission height. In the upper glass substrate 2, a black matrix 8 is formed at the boundary of the red, green, and blue sub pixel cells to improve contrast, and the red, green, and blue phosphors 6 are interposed between the black matrixes 8. Is formed. As shown in FIG. 2, the field emission array 32 formed on the lower glass substrate 12 includes a cathode electrode 14, an emitter 16, a gate insulating layer 18, a gate electrode 20, and a focusing insulating layer ( 22) and a focusing electrode 24. The cathode electrode 14 is formed on the lower glass substrate 12 in a direction orthogonal to the gate electrode 20 to supply current to the emitter 16. The emitter 16 is formed in the form of a conical tip to emit electrons 30 by the current signal supplied from the cathode electrode 14. The gate insulating layer 18 insulates between the cathode electrode 14 and the gate electrode 20. The gate electrode 20 is used as an extraction electrode for drawing electrons. The focusing insulating layer 22 insulates between the gate electrode 20 and the focusing electrode 24. The focusing electrode 24 serves to connect electrons drawn from the emitter 16. In order to display an image or an image, a negative (-) cathode voltage is applied to the cathode electrode 14 and a positive (+) gate voltage is applied to the gate electrode 20. Then, as the electric field is formed between the cathode electrode 14 and the gate electrode 20, electrons 30 are emitted from the tip of the end of the emitter 16 by the quantum mechanical tunneling phenomenon. The emitted electrons 30 pass through holes between the gate electrodes 20 and are connected by the focusing electrode 24 ′ to which a negative focus voltage is applied. Electrons connected by the focusing electrode 24 are accelerated toward the anode electrode 4 to which a positive anode voltage is applied and collide with the phosphor 6. When the electrons 30 collide with the phosphor 6 in this manner, the phosphor 6 is excited and emits light to generate visible light of any one of red, green, and blue colors.

FED has a field emission space of 10^-6Maintain high vacuum above Torr. The distance between the emitter 16 and the gate electrode 20 is spaced at submicron intervals so that 10 between the emitter 16 and the gate electrode 20⁷V / cm If a high electric field of degree is applied, discharge or insulation breakdown may occur between the emitter 16 and the gate electrode 20 if the emitter 16 and the gate electrode 20 are not maintained in high vacuum. In addition, if the field emission space is not maintained at high vacuum, the neutral particles present in the panel collide with the electrons 30 to generate cations. The cations thus generated impair the emitter 16 to degrade the emitter 16 or collide with the electron 30 to attenuate the acceleration energy of the electron 30 to lower the brightness. In order to prevent this, a vacuum process for making the inside of the panel in a vacuum state in the manufacturing process of the FED is required.

3 and 4, an exhaust port 48 is formed at one side of the lower glass substrate 12, and an exhaust tube is connected to the exhaust port 48 by frit glass 36. Next, the spacer 10 and the frit glass 34 are formed between the upper glass substrate 2 and the lower glass substrate 12 with the exhaust port 48 interposed therebetween (step S2). The frit glass 34 is presintered respectively. The binder of the organic component contained in the frit glass 34 at the time of plastic sintering is burned out. Here, since the sintering temperature characteristics are different according to the composition of the frit glass 34, an appropriate temperature should be selected and heat-treated for plasticization. After the sintering, the upper glass substrate 2 and the lower glass substrate 12 are bonded and aligned, and the main glass substrate 2 and the lower glass substrate are sintered at about 450 ° C. higher than the sintering temperature. (12) is fully bonded. (Step S3) After the sintering / bonding process, the getter 40 is mounted in the exhaust tube 42 and the pump is heated while heating the panel to remove the water (H ₂ O) component inside the panel. The gas inside the panel is exhausted to the outer chamber by using the 46 (step S4). When the degree of vacuum inside the panel reaches a desired level during exhaust, the local heating device 38 installed adjacent to the exhaust tube 42 is opened. In this case, the panel and the outer chamber are separated by a pinch-off process in which the middle portion of the exhaust tube 42 is cut off (step S5). Because it falls, activate getter 40 at high temperature This process of lead (step S6)

In general, a method of mounting the getter 40 includes mounting the getter 40 inside the panel before joining the substrate and mounting the getter 40 just above the pinch-off point in the exhaust tube 42 after joining the substrate. There is a way. The method of pre-mounting the getter 40 in the panel has an advantage in that the gas adsorption efficiency for the field emission array 32 is relatively high when the getter is mounted in the panel close to the field emission array 32. However, in the method of pre-mounting the getter 40 inside the panel, the getter 40 is adhered to the upper glass substrate 2 so that one surface of the getter 40 adhered to the upper glass substrate 2 adsorbs gas. Since it is impossible to increase the gas adsorption efficiency above a certain limit, the getter 40 may be contaminated by O ₂ or C during the main sintering of the frit glass 34 performed in the atmosphere. In the method of mounting the getter 40 in the exhaust tube 42 after the substrate is bonded, since the getter 40 is mounted after the main sintering, contamination is minimized, while the getter 40 is mounted in the confined space in the tube. There is a problem that the surface area of the gas adsorption efficiency is low is limited. In order to reduce the disadvantages of the conventional getter mounting methods, a bay which can reduce the number of processes by performing the panel bonding process in a vacuum atmosphere without using an exhaust tube instead of the exhaust process performed through the exhaust tube 42 has recently been performed. Development of vacuum-in-line-sealing processes is actively underway.

The conventional FED device has a problem that the size of the effective display screen is reduced because an exhaust port 48 for discharging the gas inside the panel must be formed. In other words, the exhaust port 48 is formed at one edge of the lower glass substrate 12. A dummy space 50 having a width of about 3-4 mm in the diameter of the exhaust port 48 is provided between the field emission array 32 and the frit glass 34. Accordingly, in the conventional FED, since the area of the field emission array 32 is reduced by the area of the dummy space 50, the size of the effective display screen is reduced.

Accordingly, an object of the present invention is to provide a getter of a field emission display device that can maintain an internal vacuum state in a high vacuum state.

1 is a cross-sectional view showing a field emission display of the prior art.

FIG. 2 is an enlarged cross-sectional view of a portion “A” shown in FIG. 1. FIG.

3 is a flow chart showing the vacuum process step by step in the conventional method for manufacturing a field emission display.

4 is a cross-sectional view illustrating a state in which a pump is connected to the field emission display shown in FIG. 1.

FIG. 5 is a plan view showing the position of an exhaust port shown in FIG. 4; FIG.

6 is a cross-sectional view illustrating a field emission display device according to an exemplary embodiment of the present invention.

7 is a plan view schematically showing the position of the electrode structure and the getter according to the embodiment of the present invention.

FIG. 8 is a perspective view showing the position of the getter in the field emission display shown in FIG.

9A to 9D are cross-sectional views illustrating a method of forming an FED according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

2,51: upper substrate 4,54: anode electrode

6,56 phosphor 8: black matrix

10,11: spacer 12,52: lower substrate

14,54 cathode electrode 16: emitter

17: long groove 18,58: gate insulating layer

58a: insulating material 20, 60: gate electrode

60a: electrode material 22: focus insulation layer

24: focus electrode 30: electron

32,62: field emission array 34,36: frit glass

38: local heating device 40, 41: getter

42: exhaust tube 46: pump

48: exhaust port 50: dummy space

In order to achieve the above object, a field emission display device according to the present invention includes a plurality of field emission arrays including a lower substrate, a plurality of cathode electrodes formed on the lower substrate, and a plurality of gate electrodes orthogonal to the cathode electrodes. A getter for adsorbing gas in a field emission device having a is located in the field emission array region.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 9.

Referring to FIG. 6, there is shown a FED having an upper substrate 51 on which an anode electrode 54 and a phosphor 56 are stacked, and a field emission array 62 formed on the lower substrate 52. The field emission array 62 includes a cathode electrode 54 formed on the lower substrate 52 having a plurality of long grooves 17, a gate insulating layer 58 formed on the cathode electrode 54, and gate insulation. A gate electrode 60 is formed on the layer 58 so as to be orthogonal to the cathode electrode 54. Here, the cathode electrode 60 is formed on the lower glass substrate 52 in a direction orthogonal to the gate electrode 54 to supply current to the emitter (not shown), and the gate insulating layer 58 is the cathode electrode. It serves to insulate between the 54 and the gate electrode 60. The gate electrode 60 is used as an extraction electrode for withdrawing electrons. The spacer 11 is installed between the upper substrate 51 and the lower substrate 52 to withstand the external atmospheric pressure.

7 is a plan view schematically showing the position of the electrode structure and getter according to an embodiment of the present invention.

Referring to FIG. 7, the electrode structure of the FED includes a cathode electrode 54, a long groove 17 formed in parallel with the cathode electrode 54, a getter 41 formed on the long groove, and a cathode electrode 54. And a gate electrode 60 formed to intersect with each other.

Figure 8 illustrates in detail the bottom plate structure of the FED according to an embodiment of the present invention. The FED of FIG. 8 includes a long groove 17 formed in the lower substrate 52 between the cathode electrode 54, the emitter (not shown), the gate electrode (not shown), and the cathode electrode 54, and the long groove ( And a getter 41 formed at the center of the 17. FIG. Here, the getter 41 is formed in the center of the long groove 17 located on the lower substrate between the cathode electrode 15 layers without being exposed to the active region, and serves to adsorb gas inside the panel. The getter 41 is formed in parallel with the cathode electrode 15 as shown, and can be installed in all regions except for the spacer of the panel. Therefore, the getter 41 may be formed as many as the same number of lines as the cathode electrode 15. This makes it possible to install the getter 41 in more areas than in the prior art. In addition, since the getter 41 is not caused by the lowering of the vacuum by being provided under the cathode electrode 54 layer, the lifetime and reliability can be increased.

9A to 9D are cross-sectional views showing the method of forming the FED step by step.

First, a long groove 17 having a semicircular cross section is formed on the lower glass substrate 13 between the cathode electrodes 54 by using a method such as etching as in 9a. This is to prevent the getter 41 from being exposed to space. The getter 41 is formed at the center of the long groove 17 by using a mask. When the electrode material is deposited on the lower glass substrate 13 on which the long groove 17 and the getter 41 are formed and patterned, the cathode electrode 15 as shown in FIG. 9B is formed. In addition, 9c causes the insulating material 19a to be deposited on the cathode electrode 15 and the lower glass substrate 13 by a predetermined thickness, and the electrode material 21a is again deposited thereon. The electrode material 21a is patterned by a photolithograpy as shown in FIG. 9D to form a gate electrode 21, and the insulating material 19a is etched using the gate electrode 21 as a mask. The etched insulating material is then formed as the gate insulating layer 19. In fact, the getter is a one-step process that maintains the vacuum inside the panel, so the pure vacuum getter only maintains the internal vacuum at high vacuum, which can vary depending on the material, amount, and location of the getter.

Accordingly, the getter according to the embodiment of the present invention is formed more in the center of the long groove located on the lower substrate between the cathode electrodes, as opposed to the prior art, without being directly exposed in the active region.

As a result, the getter can be provided in many areas as compared with the prior art, and it is possible to be formed under the cathode electrode layer so as not to cause a drop in vacuum and to cause ashing.

As described above, in the field emission display device according to the present invention, a getter may be formed in the center of the long groove located on the lower substrate between the cathode electrodes in the active region to maintain the inside of the panel in a high vacuum state. In addition, since it is possible to form in any space except the spacer in the prior art, the surface area of the getter is significantly larger than that of the getter mounted on the exhaust tube, so that the outgassing gas can be absorbed as much as possible to improve the service life. In addition, since the getter is installed below, the vacuum drop and wear of the emitter tip may be reduced due to the collision of electrons and gases from the cathode electrode. Furthermore, the FED according to the present invention does not have an exhaust port, so that the field emission array and the effective display screen area can be increased accordingly, which is advantageous for large area, and also provides more getter area in the active area so that the inside of the panel is always high vacuum. It is possible to maintain the vacuum pressure and to prevent the vacuum from dropping due to the field emission.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (3)

Lower substrate, A plurality of cathode electrodes formed on the lower substrate; And a getter for adsorbing gas in a field emission element having a plurality of field emission arrays, which are display areas by a plurality of gate electrodes orthogonal to the cathode electrode, located in the field emission array region. The method of claim 1, And the getter is formed so as not to be exposed to the outside. The method of claim 2, And a long groove is formed in the lower substrate between the cathode electrodes, and the getter is formed in the long groove.