KR20040054183A - production method of field emission display - Google Patents

Abstract

PURPOSE: A method is provided to prevent damages of an emitter and a getter and permitting the getter to be arranged in a panel by lowering a sealing temperature. CONSTITUTION: A field emission display device comprises a field emitter for emitting electrons; a cathode plate(17) where the field emitter is arranged; an anode plate(12) spaced and opposed from the cathode plate, and which has a phosphor screen; and a plane electrode spaced and opposed from the anode plate, and which has a plurality of electron beam passing holes. A method for manufacturing the field emission display device is characterized in that both a sealing method using a heating furnace(24) and a sealing method using a laser(41) are adopted so as to lower the final sintering temperature.

Description

Production method of field emission display

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a field emission display device, and in particular, spaced apart from a field emitter in which electrons are emitted, a cathode plate on which the field emitter is formed, an anode plate on which a phosphor screen is formed, and an anode plate at predetermined intervals. The present invention relates to a method for manufacturing a field emission display device comprising a planar electrode and a frame for separating the anode plate and the cathode plate at predetermined intervals.

With the development of information and communication technology, the importance of display is emphasized more than ever, with the advent of the multimedia era. Therefore, the importance of the new display of light weight, thinness, high quality and low power consumption is emphasized more than ever. Field emission displays, which can have the same performance as a Cathode Ray Tube (CRT) in appearance such as a liquid crystal display, are drawing attention.

Development of field emission display devices is under development in all areas ranging from high-quality color panels for portable information terminals to large displays. LCD and plasma display pannels (PDPs) are already commercialized. Are on stage.

In addition, the field emission display device, which is expected to be practically used in the near future, is drawing attention as a next-generation flat panel display for overcoming all the disadvantages of these displays.

In particular, the field emission display device has a simple electrode structure, high-speed operation based on the same principle as a CRT, and has various colors and high luminance.

1A is a cross-sectional view of a conventional field emission display device.

Referring to FIG. 1A, a conventional field emission display device includes an anode plate 12 having a cathode plate 17 and a phosphor 15 emitting electrons by an electric field, the cathode plate 17, and an anode plate 12. It consists of a spacer 11 to maintain a predetermined space therebetween.

In more detail, the cathode plate 17 has a cathode electrode 19 formed on the cathode glass substrate 18, and an emitter 20 emitting electrons on the cathode electrode 19. The gate electrode 22 is formed as an extraction electrode that allows electrons to be extracted from the emitter 20.

In addition, a gate insulator 21 which is an insulating layer is formed between the gate electrode 22 and the cathode electrode 19.

In addition, the anode plate 12 includes an anode electrode 14 formed with a phosphor 15 that collides with electrons to generate light, and a black matrix 16 for increasing contrast of the front surface of the anode glass substrate 13. ) Is formed at the boundary of the red, green, and blue sub pixel cells of the phosphor 15.

In addition, the spacer 11 is formed so that the space between the anode plate 12 and the cathode plate 17 provides the height of the field emission at a predetermined pressure.

1B is a perspective view for explaining an operation of a conventional field emission display device.

Referring to FIGS. 1A and 1B, the operation of the conventional field emission display device is described. When a sufficient voltage is applied to both the gate electrode 22 and the cathode electrode 19, a strong electric field is formed thereby. In the emitter 20, electrons 23 are emitted by the quantum mechanical tunneling phenomenon.

The emitted electrons 23 pass through the holes between the gate electrodes 22 and are accelerated toward the anode electrode 14 to which the anode voltage is applied to collide with the phosphor 15.

When the electrons 23 collide in this way, the phosphor 15 is excited and emits light to generate visible light of any one of red, green, and blue colors.

Therefore, the color display is realized by the red, green and blue phosphor 15 dots arranged in a matrix.

Due to its driving characteristics, the field emission display device must maintain a high vacuum state in which the vacuum inside the panel is 10 to 6 Torr or more.

In the field emission display device, a high electric field of about 10V / cm is applied between the emitter 20 and the gate electrode 22 by being spaced apart by a submicron interval between the emitter 20 and the gate electrode 22 which are electron emission sources. If the space between the emitter 20 and the gate electrode 22 is not maintained in a high vacuum, the neutral particles existing inside the panel collide with the electrons 23 to generate cations.

The cations thus generated deteriorate the luminance by colliding with the emitter 20 to deteriorate the emitter 20 or colliding with the electron 23 to reduce the acceleration energy of the electron 23.

In order to prevent this, in the manufacturing process of the field emission display device, a vacuum process for making the inside of the panel into a vacuum state is required.

2A is a flowchart of a process of vacuum packaging using a vacuum pump in the manufacturing process of a conventional field emission display device.

Referring to FIG. 2A, a cathode panel and an anode panel are prepared (s100) (s200), and the cathode panel and the anode panel are bonded (s300).

Then, a getter for recovering the degree of vacuum is mounted and the gas inside the panel is exhausted to the outside by using a pump (s400).

Activate the cathode panel and isolate it from the outer chamber (s500).

Then, the getter is activated to remove the gas therein (s600).

2B is a schematic diagram of a process of sintering and bonding the cathode plate and the anode plate during the manufacturing process of the conventional field emission display device.

2B, an exhaust port is formed at one side of the cathode plate 17, and the exhaust port is connected to the exhaust tube 26 by the frit glass 25.

The frit glass 25 is formed in the anode plate 12 between the anode plate 12 and the cathode plate 17 in a state where the spacer 11 is first installed.

The height of the frit glass 25 between the anode plate 12 and the cathode plate 17 should be about 1 to 2 mm higher than the spacing of the final panel in consideration of the height of 30 to 40% reduction during sintering.

Subsequently, when the main sintering, the anode plate 12 and the cathode plate 17 are compressed and adhered to each other, thereby reducing the interval between the final panels.

The binder of the organic component contained in the frit glass 25 is burned out during plastic sintering, and the frit glass 25 has a different sintering temperature characteristic depending on the composition so that an appropriate temperature is selected for plastic sintering. Heat treatment.

The pre-sintered anode plate 12 and the cathode plate 17 are bonded, aligned and entered into the main sintering process. The main sintering moves the prepared panel to the heating furnace 24, which is about 400 ° C. to 450 ° C. higher than the pre-sintering temperature. Do it at

Through the main sintering, the anode plate 12 and the cathode plate 17 are completely bonded.

On the other hand, when the element is sintered at high temperature, the gate emission, the emitter, the cathode, and the like, which are the electron emission sources of the field emission display device, react with oxygen or carbon in the air, resulting in poor light emission characteristics. ) Is flowed into the panel or the entire furnace 24 to prevent the elements from reacting with oxygen during the high temperature process.

FIG. 2C is a diagram illustrating a pumping process and an activation process of a getter in the manufacturing process of the conventional field emission display device.

Referring to FIG. 2C, the sintered and coalesced panel is connected to the vacuum pump 31 and pumped while being heated to remove impurities in the panel.

When the panel reaches the desired degree of vacuum while heating the panel in the heating furnace 24, one side of the exhaust tube 26 is heated by the local heater 33.

As the local heater 33 is heated, the exhaust tube 26 melts, and the panel is isolated from the outside to complete an independent panel (pinch-off process).

At this time, since the internal vacuum degree of the insulated panel falls again during the pinch-off process, the getter 34 mounted in advance is activated at a high temperature to recover the vacuum degree again.

As described above, the technique for maintaining the exhaust of the field emission display and the vacuum after the exhaust is mainly based on the conventional tube exhaust method adopted by the CRT. Thus, the sealing process of the field emission display is performed at high temperature. The focus is on how to effectively block oxidation of the site.

Since the oxidation problem is directly / indirectly related to the lifetime and reliability of the panel, the conventional packaging process has many problems.

In other words, the existing sealing method exposes the panel to high temperature during sintering, so even if inert gas is flowed, characteristics due to oxidation of emitter by oxygen or reaction with other gases are deteriorated. In the process of attaching to the back side of the plate, there is a risk that the elements of the cathode plate are contaminated by the organic binder included in the frit glass.

In particular, the emitter element can be the most fatal problem because it directly affects the life of the panel.

In addition, since the getter is mounted inside the exhaust tube, it is difficult to effectively control outgassing from a wider area as the size of the panel increases.

The manufacturing method of the field emission display device according to the present invention is to reduce the sealing temperature and solve the problem of oxidation or damage of the emitter by using a sealing method using a laser in addition to the conventional sealing method by a heating furnace.

In addition, the manufacturing method of the field emission display device according to the present invention is to provide a more efficient high vacuum maintenance by installing the getter inside the panel due to the lowering the sealing temperature.

In addition, the field emission display device according to the present invention is intended to reduce the damage of the emitter by the oxidation of the emitter or other gases.

1A is a cross-sectional view of a conventional field emission display device.

1B is a perspective view for explaining the operation of a conventional field emission display device.

FIG. 2A is a flow chart of a process of vacuum packaging using a vacuum pump in the manufacturing process of a conventional field emission display device. FIG.

Figure 2b is a schematic diagram of a process of sintering and bonding the cathode plate and the anode plate during the manufacturing process of the conventional field emission display device.

2C is a view illustrating a pumping process and an activation process of a getter in the manufacturing process of the conventional field emission display device.

3 is a cross-sectional view of a field emission display device according to the present invention;

4A illustrates an anode plate and a frame in a method of manufacturing a field emission display device according to the present invention.

4B is a view for explaining a frame of the manufacturing method of the field emission display device according to the present invention;

5 is a view illustrating a first sintering process of an anode plate on which a frame is formed in the method of manufacturing a field emission display device according to the present invention.

6 is a view illustrating coupling of a cathode plate having an exhaust tube coupled to a frame in the method of manufacturing a field emission display device according to the present invention;

7 is a view illustrating mounting of a getter of the field emission display device according to the present invention;

8 is a view illustrating a sealing process of a method of manufacturing a field emission display device according to the present invention.

9 is a view for activating a getter in the method of manufacturing a field emission display device according to the present invention;

<Explanation of symbols for main parts of drawing>

11; Spacer 12; Anode plate

13; Anode glass substrate 14; Anode electrode

15; Phosphor 16; Black matrix

17; Cathode plate 18; Cathode glass substrate

19; Cathode electrode 20; Emitter

21; Gate insulator 22; Gate electrode

23; Electron 24; Furnace

25; Frit glass 25a; Anode frit glass

25b; Cathode frit glass 26; Exhaust tube

27; Inert gas 28; frame

29; Flat electrodes 30; Field emitter

31; Vacuum pump 32; Electrode support

33; Local heating furnace 34; Getter

35; Jig 36; Square groove

37; Reference gap material 38; Getter gripper

40; Quartz window 41; laser

42; clamp

Hereinafter, the field emission display device according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view of a field emission display device according to the present invention.

Referring to FIG. 3, the field emission display device according to the present invention includes a cathode plate 17 provided with a field emitter 30 for emitting electrons by an electric field, and a predetermined distance from the cathode plate 17. Spaced apart and facing the anode plate 12 on which the phosphor screen 15 is formed, and the cathode plate 17 and the anode plate 12 are spaced at regular intervals by the frame 28. have.

The electrode support 32 is attached to the anode plate 12 by frit glass or the like. The electrode support 32 includes a planar electrode 29 having a plurality of electron beam through holes formed therein. It is installed at intervals.

The field emitter 30 is a flat emitter having a good straightness and easy to manufacture in an inexpensive process, and when the straightness is not good, a focusing electrode structure is used to improve the straightness of electrons.

The frame 28 has a constant width and height, and is inserted between the cathode plate 17 and the anode plate 12 in the form of a square frame along an edge portion of the cathode plate 17 and the anode plate 12. do.

In addition, both sides of the frame 28 are fused and sealed with the cathode plate 17 and the anode plate 12 by frit glass 25a and 25b.

In addition, the frame 28 is the same material as the cathode plate 17 and the anode plate 12, it is preferable that the same degree of expansion or contraction by heat.

Referring to the operation of the field emission display device configured as described above, when electrons are emitted from the field emitter 30, the anode plate 12 passes through the planar electrode 29 to which the same voltage as the anode electrode is applied through the vacuum medium. The screen is constructed by colliding with the phosphor screen 15 formed on the screen.

Hereinafter, a method of manufacturing the field emission display device according to the present invention will be described in detail.

4A illustrates an anode plate and a frame in a method of manufacturing a field emission display device according to the present invention.

Referring to FIG. 4A, the frit glass 25a is coated on the anode plate 12 which has completed the phosphor process such as a black matrix, a metal back, and a phosphor coating on the anode glass substrate.

In the case of the high-voltage field emission display device, a high voltage can be applied only by maintaining a distance of 1 mm or more between the anode plate 12 and the cathode plate (not shown), but it is very difficult to maintain a height of 1 mm or more using the frit glass 25a alone.

Therefore, it is preferable to use the glass frame 28 between the anode plate 12 and the cathode plate (not shown).

In the present invention, based on the method of using the glass of the same material used in the anode plate 12 and the cathode plate (not shown) as the frame 28, the frit glass is applied to the bottom and top of the frame 28 in the center. do.

For convenience, the frit glass between the frame and the anode plate is called an anode frit glass, and the frit glass between the frame and the cathode plate is called a cathode frit glass.

The thickness of the anode frit glass 25a to be applied to the anode plate 12 is preferably 600 to 800 µm.

The anode fleet glass 25a has a height determined through a drying process after application, and the height is approximately 300 to 400 μm during the first application.

After the second coating, the height of about 600-800 μm is maintained. When the anode frit glass 25a is completely dried after the second coating, the frame 28 is mounted.

Then, the height after the drying process is determined differently by the interval of the target panel, it is determined to be 200 ~ 300㎛ lower than the interval of the target panel.

Dividing the application of the anode frit glass 25a in two times is carried out when the frame 26 is placed on the anode frit glass 25a in a viscous state and dried, and the binder contained in the anode frit glass 25a This is because air is pressed into the frame 26 to form voids in the glass substrate of the anode plate 12.

Therefore, after the voids are prevented in advance by the first application and drying process, the second application and the frame 28 are mounted.

4B is a view for explaining a frame of the method for manufacturing a field emission display device according to the present invention.

Referring to Figure 4b, the glass frame 28 can be made through a conventional mold, but is simply produced water jet (Water jet) technology.

Water jet technology refers to a technique for cutting a structure by shooting high water pressure along a cutting surface. When water jet technology is applied to cutting glass materials, the glass material can be manufactured without thermal shock, but the surface is There is a disadvantage of being rough.

Drying is performed at 120 ° C. for about 5 minutes to solidify the frit glass so that structures attached to the frit glass do not fall or twist.

5 is a view illustrating a primary sintering process of an anode plate on which a frame is formed in the method of manufacturing a field emission display device according to the present invention.

Referring to FIG. 5, primary sintering means complete sintering up to the frame 28. In the case of a conventional pratt panel display, the final sintering process is generally around 430 to 480 ° C. and varies slightly depending on the frit glass used. .

After the primary sintering, the height of the anode frit glass 25a is reduced by 30 to 40% of the height before sintering, and the height to the frame 28 of the primary sintering anode plate 12 is generally the target panel gap. It is preferable to maintain the height minus 200 ~ 300㎛.

Since the cathode frit glass must then be applied over the height to the frame 28 which is precisely fitted, the height to the frame 28 is preferably sintered upside down the anode plate 12.

The surface roughness groove 36 has a plate-shaped jig 35 below, and the anode plate 12 on which the frame 28 is formed is turned upside down so as to be positioned above the jig 35.

As the sintering proceeds, the gap between the anode frit glass 25a shrinks, and the reference gap material 37 is previously installed above the jig 35 so as not to shrink beyond the target gap.

The rectangular groove of the jig 35 is equal to or larger than the area including the phosphor area, and the rectangular groove 36 allows the binders coming out of the anode frit glass 25a to easily escape to the outside.

6 is a view for explaining the coupling of the cathode plate combined with the exhaust tube to the frame in the method for manufacturing a field emission display device according to the present invention.

Referring to FIG. 6, the cathode frit glass 25b is coated on the upper side of the frame 28 of the primary sintered anode plate 12.

Unlike the anode frit glass 25a, the cathode frit glass 25b is only subjected to the sintering process after application.

The sintering process is different depending on the burn-out conditions of the binder used, but it is preferable to perform about 1 hour at about 300 ℃.

In addition, since the height determined in the coating and drying process is also reduced by about 20 to 30% through the pre-sintering process, it is preferable to apply the coating in consideration of the height in advance when applying the cathode frit glass 25b.

In addition, the height of the cathode frit glass 25b is preferably 400 to 500 µm.

On the other hand, the back of the cathode plate 17 is coated with frit glass 25 and the exhaust tube 26 is coupled.

In addition, the thickness of the frit glass 25 for coupling the exhaust tube 26 is preferably 200 ~ 300㎛.

After the exhaust tube 26 is joined, the exhaust tube 26 is fixed so as not to fall through the drying process at about 120 ° C., and the plastic tube is sintered so as not to be shrunk over the target interval using the reference gap material as described in FIG. do.

7 is a view for explaining the mounting of the getter of the field emission display device according to the present invention.

Referring to FIG. 7, the getter 34 is mounted on the anode plate 12 that has been finished up to the sintering process of the cathode frit glass.

The getter 34 is formed between the gap between the phosphor screen 15 and the frame 28 and is secured by a getter gripper 38.

The getter 34 should not be damaged at this temperature since the final sealing process takes place at around 300 ° C.

When the mounting of the getter 34 is finished, it is aligned with the anode plate 12 prior to sealing the cathode plate.

After alignment, clamp the anode plate and cathode plate and move them to the heating furnace.

8 is a view illustrating a sealing process of a method of manufacturing a field emission display device according to the present invention.

Referring to FIG. 8, the anode plate 12 and the cathode plate 17 fastened by the clamp 42 are positioned inside the heating furnace 24.

The heating furnace 24 is formed with a quartz window 40 on one side so that the laser beam can be transmitted.

The panel bonded by the clamp 42 starts to become viscous when it reaches the softening point of the cathode frit glass 25b.

In particular, since the cathode plate 17 and the anode plate 12 are firmly bonded by the clamp 42, they easily become viscous.

At this time, the cathode frit glass 25b formed 400 to 500 µm higher than the interval of the target panel is shrunk, and the correct gap is formed by the reference gap material 37.

However, since it is not completely sealed in the vicinity of the softening point, the final sealing process is completed using the laser 41 through the quartz window 40 to locally move along the surface of the cathode frit glass 25b to complete the sealing. .

The sealing of the exhaust tube 26 is also completed by the laser 41 in the same manner as described above.

As described above, conventionally, the sealing using the heating furnace 24 and the sealing using the laser 41 are performed in parallel so that the existing sealing is performed at a temperature of 50 to 100 ° C lower than the sealing temperature.

Thereafter, the inside of the panel is brought into a vacuum state by pumping using the exhaust tube 26 while heating in the heating furnace 24.

9 is a view for activating a getter in the method for manufacturing a field emission display device according to the present invention.

Referring to FIG. 9, unlike the method in which the getter is mounted on the exhaust tube, the getter 34 is mounted on the anode plate 12 and the getter 34 is activated by using the laser 41.

The cycle time of the laser 41 is determined according to the activation temperature of the getter 34, and the getter 34 is activated by the average holding temperature returned through the cycle.

As the getter 34 is activated, the bad vacuum degree is recovered again through the pinch-off process of the exhaust tube.

In the method of manufacturing the field emission display device according to the present invention, the sealing temperature can be lowered by using a sealing method using a conventional heating method and a laser method, so that the problem of oxidation or damage to the emitter can be alleviated. There is an advantage.

In addition, the manufacturing method of the field emission display device according to the present invention has the advantage that it is possible to install the getter inside the panel due to the lowering of the sealing temperature, it is possible to maintain a more efficient high vacuum by preventing damage to the getter.

Claims (5)

A field emitter in which electrons are emitted by an electric field, a cathode plate on which the field emitter is installed, an anode plate facing and spaced apart from the cathode plate at a predetermined interval, and formed with a phosphor screen, the anode plate and a predetermined In the manufacturing method of the field emission display device comprising a planar electrode formed with a plurality of electron beam through-holes spaced apart at intervals, in order to lower the final sintering temperature, the sealing method by a heating furnace and the laser sealing method in parallel A method of manufacturing a field emission display device. The method of claim 1, And using a frame such that the cathode plate and the anode plate are spaced apart from each other at predetermined intervals. The method of claim 1, A method of manufacturing a field emission display device comprising using a jig to maintain a constant thickness of the frit glass adhered to the anode plate and the cathode plate. The method of claim 1, And a getter mounted between the frame and the place where the phosphor screen of the anode plate is formed in order to maintain the internal space between the anode plate and the cathode plate in a vacuum. The method of claim 4, wherein And a laser is used to activate the getter.