JPH0822785A - Flat type display device and its manufacture - Google Patents

Abstract

PURPOSE:To maintain an ultra-high vacuum condition by restraining gas diffusion, and stabilize display by arranging an evaporation type getter exposed in a vacuum clearance between two panels on an inner wall surface in an image screen display area in which a field emission type negative electrode is arranged. CONSTITUTION:In an image screen display area 1A being a screen of matrix display, an interval 30 between a front side panel 10 having a fluorescent screen 12 on an inside surface and a back side panel having emitters 25 on an inside surface is set in about 100mum, and an ultra-high vacuum is kept. A belt-like evaporation type getter 19 is uniformly arranged over the whole area 1A between the panel 10 and the fluorescent screen 12. The getter 19 is composed of a barium thin film or the like formed by a mask evaporation method, and a thickness is about 1000Angstrom , and is sufficiently smaller than the clearance 30. Therefore, speedy gettering is performed to blowoff of gas in the area 1A. The getter 19 may be arranged on both front and back sides in the area 1A. The getter 19 is evaporated in a condition of being held in a vacuum after surface purification processing of the panel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat type display device having a large number of electron sources (electron guns) composed of field emission type cathodes as means for exciting a phosphor screen, and a method for manufacturing the same.

A display device (FED: Field Emitter De) utilizing field emission (also called cold cathode emission).
display) is capable of high definition and high brightness display,
It is attracting attention as a next-generation display device.

[0003]

2. Description of the Related Art An FED is a flat display tube having a thickness of several millimeters, in which a pair of panels are opposed to each other with a minute gap therebetween and the periphery of the panels is sealed. A fluorescent film is provided on the inner surface of the front panel, and micron-sized field emission cathodes are arranged for each pixel on the rear panel. The area where the field emission cathodes are arranged is the screen display area.

In manufacturing the FED, at the same time as sealing the periphery of the panel, a chip-off tube that has been temporarily fixed to the exhaust port at the peripheral edge of one panel is bonded, and then the chip-off tube is used. Exhaust the inside. Then, the tip-off pipe is melted and the exhaust port is closed to seal the internal vacuum gap.

In such an FED, in order for the field emission type cathode (hereinafter referred to as "emitter") to function reliably, the gap between the emitter and the phosphor screen should be at least 10 ^-7 to 1 -1.
It is necessary to maintain a so-called ultra-high vacuum of 0 ^-8 Torr. Therefore, a non-evaporable getter (bulk getter) is usually fixed in the tip-off tube.

Further, conventionally, there has been proposed a method for increasing the bulk getter volume by providing a groove surrounding the entire phosphor screen (display surface) on the inner surface of the front panel and embedding the bulk getter in the groove. (Japanese Patent Laid-Open No. 5-12
No. 1015).

[0007]

When the bulk getter is used as in the prior art, the position of arrangement is limited. In other words, even the thinnest bulk getter has a thickness of 150μ.
Since it is about m, the bulk getter cannot be accommodated in the internal gap of about 100 μm.

Therefore, the screen display area where gas is likely to be released during use and the getter arrangement position are separated from each other,
There is a problem in that the gas that gushes out from the inner wall of the screen display area is not immediately adsorbed but diffuses into the surroundings, and the phosphor screen and the emitter are easily contaminated and the emitter is easily damaged by arc discharge. Also, since the gap is narrow and the conductance of gas flow is small, the degree of vacuum in the screen display area is locally damaged,
There was also the problem of unstable display.

The present invention has been made in view of the above problems, and an object thereof is to suppress gas diffusion in a screen display area as much as possible, maintain a high vacuum state, and stabilize the display. There is.

[0010]

In order to solve the above-mentioned problems, an apparatus according to the invention of claim 1 is as follows, as shown in FIG.
A front panel having a fluorescent film and a rear panel having a large number of field emission type cathodes for screen display for selectively exciting the fluorescent film are opposed to each other through a vacuum gap. In the flat display device, an evaporation type getter exposed to the vacuum gap is provided on an inner wall surface in a screen display area where the field emission cathode is arranged.

According to a second aspect of the present invention, the evaporation type getter is arranged substantially evenly with respect to each pixel of the screen display. In the apparatus according to the invention of claim 3, the evaporative getter is provided on the inner wall surface of each of the front side panel and the rear side panel.

According to a fourth aspect of the present invention, the device has a recess for locally increasing the size of the vacuum gap in the screen display region, and the evaporation getter is provided at the bottom of the recess.

According to a fifth aspect of the present invention, there is provided an apparatus including a partition for defining the vacuum gap, and the evaporation type getter is provided on a side surface of the partition. According to a sixth aspect of the present invention, there is provided a method for manufacturing a flat-type display device, wherein the evaporative getter is provided on one or both of the pair of panels on the front side and the back side in a vacuum, and then the vacuum getter is maintained, A pair of panels are arranged to face each other and hermetically seal the periphery.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a flat-type display device, wherein after performing surface cleaning treatment on one or both of the pair of panels in a vacuum, the evaporation type while maintaining a vacuum state. A getter is provided.

[0015]

[Function] Impure gas that has sprung from the inner wall of the screen display area
It is quickly adsorbed by the nearby evaporative getter.

By equalizing the getter arrangement for each pixel, gettering is performed uniformly regardless of the position of the screen display area, and the uniformity of display characteristics is maintained. If both panels are sealed in a vacuum to seal the inner gap, the inner gap can be made a high vacuum regardless of conductance, unlike the case where the inside is exhausted after sealing under atmospheric pressure. .

When an arc discharge due to gas release occurs near the recess having the evaporative getter at the bottom, the inside of the recess is in a higher vacuum than the surroundings, and therefore the gas is recessed due to the vacuum degree gradient. It spreads (diffuses) and suppresses the spread of arc discharge.

[0018]

1 is a sectional view showing the structure of an FED 1 of the first embodiment, FIG. 2 is a partial perspective view showing the internal structure of the FED 1, and FIG. 3 is a view showing an example of the structure of an electron source 22.

The FED 1 comprises a front panel 10 having a glass plate 11 as a base and a rear panel 20 having a glass plate (or a silicon plate) 21 as a base, and is a flat panel capable of full-color matrix display. It is a shape display device. Both panels 10 and 20 are arranged to face each other with a gap of about 100 μm, and the peripheral edge portion of the facing region is sealed by the low melting point glass layer 35. The internal gap 30 is 10
It is a vacuum of ^-7 to 10 ^-8 Torr, and the gap size is made uniform by the scattered arrangement of bead spacers (not shown).

In the screen display area IA which serves as a screen for matrix display, the fluorescent film 12 is provided on the inner surface of the front panel 10 and the fluorescent film 12 is provided on the inner surface of the rear panel 20.
An emitter 25 for exciting the is arranged.

As shown in FIG. 2, the arrangement pattern of the fluorescent film 12 is a stripe pattern in which the three primary colors (R, G, B) for full-color display are alternately switched in one direction, and the strip-shaped fluorescent films 12 and An anode electrode (not shown) made of a transparent conductive film is provided between the glass plate 11 and the glass plate 11.

In the rear panel 20, the glass plate 2
An electrode matrix is composed of the cathode electrodes 23 arranged on the first electrode and the gate electrodes 26 extending in the same direction as the fluorescent film 12. The cathode electrode 23 and the gate electrode 26 intersect with each other through the insulating layer 24, and the electron source 22 that defines a unit light emitting region of matrix display is formed at each intersection. The size of the unit light emitting region is, for example, 100.
It is about μm square.

As shown in FIG. 3, the electron source 22 has a conical emitter (also referred to as an emitter tip) 25 electrically integrated with the cathode electrode 23, and a gate electrode 26 having an opening 26a exposing the emitter 25. , And emitter 2
5 is composed of an insulating layer 24 for forming an air gap around 5 and maintaining insulation from the gate electrode 26, and actually has several hundreds of emitters 25 or more. Since the method of forming the electron source 22 is known, its description is omitted here.

When a predetermined voltage is applied between the emitter 25 and the gate electrode 26, field emission occurs at the tip of the emitter 25. Therefore, for example, the cathode electrode 23 and the gate electrode 26 are selected in a line-sequential manner, and an electron beam is emitted from a specific electron source 22, so that the fluorescent film 12 facing the electron source 22 can be selectively made to emit light. it can. In the FED 1, one pixel for matrix display is composed of unit light emitting regions of three colors arranged in the extension direction of the cathode electrode 23, and gradation display of each color is performed by controlling the light emission time according to the display color of the pixel.

The cathode electrode 23 and the gate electrode 2
6, and the anode electrode is led out from the screen display area IA to the end of the panel, and in order to connect these electrodes to an external circuit, the electrode lead-out portion of one panel projects to the other panel, The side and back panel sizes and stacking positions are selected.

As shown in FIGS. 1 and 2, in the FED 1, strip-shaped evaporation type getters (flash getters) are evenly distributed between the fluorescent films 12 of the front panel 10 over the entire screen display area IA. 19 are provided.

The evaporation type getter 19 is a barium thin film formed by a mask vapor deposition method for partially covering the adherend surface using BaAl ₄ powder as a raw material, and its thickness is about 1000Å, which is sufficiently smaller than the vacuum gap size. Is.

The evaporative getter 19 provides quick gettering for gas emission in the screen display area IA. As a result, in the FED 1, the gas diffusion is localized and the internal high vacuum state is maintained, and even if a large amount of gas is discharged which causes arc discharge, the arc does not spread and damage to the emitter 25 is minimized. To be

In manufacturing the FED 1 having the above structure,
After the phosphor 12, the low melting point glass for sealing, and the bead spacers are provided on the glass plate 11 in an appropriate order by screen printing or the like, surface purification treatment is performed in vacuum.
Examples of the surface cleaning treatment include baking, electron irradiation, ion irradiation, ultraviolet irradiation, and plasma treatment. Further, baking in a hydrogen atmosphere may be added.

Following the surface cleaning treatment, the evaporation type getter 19 is vapor-deposited in a state where a vacuum is maintained or a processing environment is made a vacuum without exposing the atmosphere from a hydrogen atmosphere to the atmosphere. Then, the vacuum state is maintained even after the vapor deposition.

On the other hand, also on the rear panel 20, after the electrode matrix including the electron source 22 is provided on the glass 21, the surface cleaning treatment is performed similarly to the front panel 10. However, in addition to the above-mentioned processes, aging is performed to operate the electron source 22 in a vacuum. Then, the vacuum state is maintained even after aging.

After that, the panels 10 and 20 on both sides kept in a vacuum state are set to a vacuum degree of 10 ^−7, which is the vacuum degree of the internal gap during use.
It is placed in a vacuum environment of -10 ^-8 Torr and the periphery is sealed by heating with a hot plate or the like to seal the facing gap.
As a result, the FED1 is completed.

As described above, the evaporative getter 19 functions effectively for a long period of time by continuously performing a series of processes from the surface purification process to the sealing through the getter vapor deposition in substantially vacuum. The gap 30 can be formed.

In order to manufacture the FED 1, it is preferable to use a manufacturing facility provided with a plurality of vacuum chambers suitable for each stage of processing and a transfer means including a manipulator, each vacuum chamber being partitioned by a load lock mechanism.

FIG. 4 is a plan view schematically showing the structure of the FED 2 of the second embodiment. 4, constituent elements corresponding to those in FIGS. 1 to 3 are designated by the same reference numerals. The same applies to the following figures.

The basic configuration of FED2 is the same as that of FED1 described above. However, in the FED2, the screen display area IA
Evaporable getters 19, 19 on both the front and back sides of the inside
B is provided.

That is, as shown in FIG. 4A, a strip-shaped evaporation type getter 19 is provided between the fluorescent films 12 on the front panel 10 and adjacent to the rear panel 20. A square evaporation type getter 19B is provided in the center of the × 2 electron sources 22.

FIG. 5 is a perspective view showing the structure of the main part of the FED 3 of the third embodiment. Similar to the FED 2 described above, the FED 3 is provided with a rectangular evaporation type getter 19C on the rear panel 20 so as to surround each electron source 22 from four corners. However, in the FED3, 10 is formed on the surface layer of the insulating layer 24.
A quadrangular recess 24a having a depth of about μm is formed, and an evaporation type getter 19C is provided at the bottom of the recess 24a.

As a result, the electron source 2 near the depression 24a
When the arc discharge due to the gas release occurs in No. 2, the inside of the recess 24a is in a higher vacuum than the surroundings, so the gas flows into the recess 24a due to the vacuum degree gradient, and the arc discharge to another electron source 22. Spread is suppressed.

FIG. 6 is a perspective view showing the internal structure of the FED 4 of the fourth embodiment. The FED 4 has partition walls 51 having a linear shape in a plan view between the fluorescent films 12 of the front panel 10, and partition walls 52 having a grid shape in a plan view and surrounding the electron sources 22 on the back panel 20. are doing. These partition walls 51, 5
Due to 2, the vacuum gap 30 is divided into equal intervals for each unit light emitting region, and high-definition display without crosstalk (without light emission blurring) becomes possible.

In the FED 4, the evaporation type getter 19D is provided so as to cover the side surface of the partition wall 51, and the partition wall 5 is formed.
An evaporation type getter 19E is provided so as to cover the side surface of No. 2. These evaporation type getters 19D and 19E can be easily formed by arranging the panels 10 and 20 and the mask in an oblique position with respect to the evaporation source during vapor deposition.

According to the above-described embodiment, there is no restriction on the arrangement space related to the thickness dimension, and the suction area can be greatly increased. Therefore, as in the conventional case, the screen display area IA
It is not necessary to bury the bulk getter by providing a deep groove surrounding the area, and it becomes easy to draw the electrode from the screen display area IA to the panel end.

In the above embodiment, the front panel 10
As for the above, a strip-shaped recess (groove) may be provided by etching the glass plate 11 and the evaporation type getter 19 may be provided therein. Further, the shapes and positions of the evaporation type getters 19 and 19B to E are not limited to the illustrated example. For example, in the front panel 10, the fluorescent film 12 may be divided and arranged for each unit light emitting region, and the evaporation type getter 19 may be provided so as to cover the inner surface except the fluorescent film 12.

In the above-mentioned embodiment, the panel sealing can be performed by other methods such as metal sealing or anodic bonding instead of using the low melting point glass. The material, shape, size, arrangement relationship and the like of each part may be appropriately selected according to the application. When a silicon plate is used as the substrate of the rear panel 20, a conductive layer to be the cathode electrode 23 can be formed by impurity diffusion, and then a conical emitter 25 can be formed by pattern etching of silicon.

In the above-described embodiment, if the evaporative getter is provided on the electron emission surface of the emitter 25, the desorption of gas is eliminated and only adsorption is performed, so that the noise of field emission due to the attachment and detachment of gas is reduced. In addition, the triggering factor (trigger) of arc discharge is reduced, and the device performance can be improved.

[0046]

According to the inventions of claims 1 to 5,
Since the getter is arranged in the screen display region where gas is likely to be released during use, gas diffusion is suppressed as much as possible, the high vacuum state is maintained, and the display can be stabilized.

According to the second aspect of the invention, in addition to the above effects, it is possible to prevent variations in the field emission characteristics within the screen display area. According to the sixth and seventh aspects of the present invention, it is possible to manufacture a display device having a clean vacuum gap in which the evaporation getter is prevented from being contaminated at the manufacturing stage and the evaporation getter effectively functions for a long period of time. You can

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an FED of a first embodiment.

FIG. 2 is a partial perspective view showing the internal structure of an FED.

FIG. 3 is a diagram showing an example of a structure of an electron source.

FIG. 4 is a plan view schematically showing the configuration of the FED of the second embodiment.

FIG. 5 is a perspective view showing a structure of a main part of an FED of a third embodiment.

FIG. 6 is a perspective view showing the internal structure of the FED of the fourth embodiment.

[Explanation of symbols]

 1, 2, 3, 4 FED (flat display device) 12 Fluorescent film 10 Front panel 20 Back panel 25 Emitter (field emission cathode) 30 Gap (vacuum gap) IA Screen display area 19 19B-E Evaporative getter 24a recess 51,52 partition wall

Claims (7)

[Claims] 1. A front panel having a fluorescent film and a rear panel having a large number of field emission type cathodes for screen display for selectively exciting the fluorescent film are provided with a vacuum gap therebetween. A flat display device having a structure facing each other, wherein an evaporation type getter exposed to the vacuum gap is provided on an inner wall surface in a screen display area where the field emission cathode is arranged. Characteristic flat display device. 2. The flat-type display device according to claim 1, wherein the evaporation type getters are arranged substantially evenly with respect to each pixel of the screen display. 3. The flat display device according to claim 1, wherein the evaporation type getter is provided on each inner wall surface of the panel on the front side and the back side. 4. A dent that locally increases the size of the vacuum gap in the screen display area, and the evaporation getter is provided at the bottom of the dent. The flat display device according to claim 3. 5. A partition for partitioning the vacuum gap is provided in the screen display region, and the evaporative getter is provided on a side surface of the partition.
The flat display device according to any one of 1. 6. A method of manufacturing a flat display device according to claim 1, wherein one or both of the pair of panels on a front side and a back side in vacuum is formed by the evaporation type device. After the getter is provided, the pair of panels are arranged so as to face each other while maintaining a vacuum state, and the periphery is hermetically sealed. 7. The manufacturing method according to claim 6, wherein after one or both of the pair of panels is subjected to surface cleaning treatment in a vacuum, the evaporation type getter is provided while maintaining a vacuum state. A method of manufacturing a flat display device, which is characterized by the above.