JP3241935B2 - Flat display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

A display device using field emission (also referred to as cold cathode emission) (FED: FieldEmitter De)
spray) is capable of displaying high definition and high brightness,
It is drawing 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 about several millimeters in which a pair of panels are arranged to face each other with a small gap therebetween and the periphery of the panels is sealed. A fluorescent film is provided on the inner surface of the front panel, and a micron-sized field emission cathode is arranged for each pixel on the rear panel. The arrangement region of the field emission cathode is a screen display region.

In manufacturing the FED, a chip-off tube temporarily fixed in advance to an exhaust port at a peripheral portion of one of the panels is bonded at the same time as sealing around the panel, and thereafter, the chip-off tube is connected through the chip-off tube. Exhaust the inside. Then, the tip-off tube is blown to close the exhaust port, and the internal vacuum gap is sealed.

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

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

[0007]

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

[0008] Therefore, the screen display area where gas emission is likely to occur during use is separated from the getter arrangement position,
There is a problem that the gas spouted from the inner wall of the screen display area is not immediately adsorbed but diffuses to the surroundings, and the phosphor and the emitter are easily contaminated and the emitter is easily damaged by arc discharge. In addition, since the gap is small and the conductance of gas flow is small, the degree of vacuum in the screen display area is locally impaired,
There was also a problem that the display became unstable.

The present invention has been made in view of the above problems, and has as its object to stabilize display by maintaining a high vacuum state by minimizing gas diffusion in a screen display area. I have.

[0010]

Apparatus according to the invention of claim 1 SUMMARY OF THE INVENTION comprises a front side of the panel having a fluorescent film, a large number of field emission for the screen display to selectively excite the fluorescent film A panel on the back side having a cathode is a flat display device having a structure opposed to each other via a vacuum gap, and a screen display area in which the field emission cathode is arranged ,
Having a depression locally increasing the size of the vacuum gap,
A getter is provided at the bottom of the recess, where the evaporable getter material is evaporated and applied .

The flat display device according to the second aspect of the present invention.
, The vacuum gap is defined in a screen display area
Evaporating getter material on the side surface of the partition wall
A getter is provided.

[0012]

[0013]

[0014]

[0015]

[Function] The impure gas flowing from the inner wall of the screen display area is
Adsorbed quickly by nearby evaporable getters.

[0016]

If an arc discharge due to gas discharge occurs near the pit having the evaporable getter at the bottom, the inside of the pit becomes higher in vacuum than the surrounding area, and the gas gradient is reduced due to the degree of vacuum gradient. , And the spread of the arc discharge is suppressed.

[0018]

1 is a sectional view showing the structure of an FED 1 according to a 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 is composed of 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. It is a shape display device. The two panels 10 and 20 are opposed to each other with a gap of about 100 μm, and the peripheral edge of the opposed region is sealed with a low melting point glass layer 35. The internal gap 30 is 10
The vacuum is ^-7 to 10 ^-8 Torr, and the gap size is made uniform by dotted arrangement of bead spacers (not shown).

In a screen display area IA serving as a matrix display screen, a fluorescent film 12 is provided on the inner surface of the front panel 10, and the fluorescent film 12 is provided on an inner surface of the rear panel 20.
Is arranged.

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

In the rear panel 20, the glass plate 2
An electrode matrix is composed of the cathode electrodes 23 arranged on the first electrode 1 and the gate electrode 26 extending in the same direction as the fluorescent film 12. The cathode electrode 23 and the gate electrode 26 intersect with an insulating layer 24 interposed therebetween, and an electron source 22 for defining a unit light emitting region of a matrix display is formed at each intersection. The size of the unit light emitting area is, for example, 100
It is about μm square.

As shown in FIG. 3, the electron source 22 includes 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 for exposing the emitter 25. , And emitter 2
5 is formed of an insulating layer 24 for forming a void around the gate electrode 5 and maintaining insulation from the gate electrode 26, and actually has several hundred or more emitters 25. Since a method for forming the electron source 22 is known, the description thereof 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, by selecting the cathode electrode 23 and the gate electrode 26 in a line-sequential manner and emitting an electron beam from a specific electron source 22, it is possible to selectively cause the fluorescent film 12 facing the electron source 22 to emit light. it can. In the FED 1, one pixel of the matrix display is composed of unit light emission areas of three colors arranged in the extension direction of the cathode electrode 23, and gradation display of each color is performed by light emission time control or the like according to the display color of the pixel.

The cathode electrode 23 and the gate electrode 2
6, and the anode electrodes are led out from the screen display area IA to the edge of the panel, and in order to connect these electrodes to an external circuit, the electrode lead-out portions of one panel are extended so as to protrude from the other panel. The side and back side panel sizes and the overlapping position are selected.

As shown in FIGS. 1 and 2, in the FED 1, a strip-shaped evaporable getter (flash getter) is uniformly provided between the fluorescent films 12 of the front panel 10 over the entire screen display area IA. 19 are provided.

The evaporable getter 19 is, for example, a barium thin film formed by a mask vapor deposition method using BaAl ₄ powder as a raw material and partially covering the adherend surface, and has a thickness of about 1000 ° which is sufficiently smaller than the vacuum gap dimension. It is.

By the evaporable getter 19, quick gettering for gas release in the screen display area IA is performed. As a result, in the FED 1, the gas diffusion is localized, and a high vacuum state inside is maintained. In particular, even if a large amount of gas is discharged, which causes an arc discharge, the arc does not spread, and damage to the emitter 25 is minimized. Can be

In manufacturing the FED 1 having the above structure,
After a phosphor 12, a low-melting glass for sealing, and bead spacers are provided in a suitable order on a glass plate 11 by screen printing or the like, a surface cleaning treatment is performed in a 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 performed.

Following the surface cleaning treatment, the evaporable getter 19 is deposited in a state where the vacuum is maintained or the processing environment is evacuated without exposing the atmosphere from a hydrogen atmosphere to the atmosphere. Then, the vacuum state is maintained 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-described processes, aging for operating the electron source 22 in a vacuum is performed. Then, the vacuum state is maintained even after aging.

Thereafter, the panels 10 and 20 on both sides kept in a vacuum state are replaced with 10 ^-7, which is the degree of vacuum of the internal gap during use.
It is placed in a vacuum environment of 10 to 10 ^-8 Torr, and the periphery is sealed by heating with a hot plate or the like to seal the facing gap.
Thus, the FED 1 is completed.

As described above, a series of processes from the surface cleaning process to the sealing through the getter vapor deposition are performed substantially continuously in a vacuum, so that the evaporable getter 19 can function effectively for a long time in a clean vacuum. The gap 30 can be formed.

For manufacturing the FED 1, it is preferable to use a manufacturing facility having a plurality of vacuum chambers suitable for each stage of processing and transport means including a manipulator, and each vacuum chamber is partitioned by a load lock mechanism.

FIG. 4 is a plan view schematically showing the structure of the FED 2 of the second embodiment. In FIG. 4, the components corresponding to FIGS. 1 to 3 are denoted by the same reference numerals. The same applies to the following figures.

The basic structure of the FED 2 is the same as that of the FED 1 described above. However, in the FED2, the screen display area IA
The evaporable getters 19, 19 are provided on both the front side and the back side of the inside.
B is provided.

That is, as shown in FIG. 4A, a strip-shaped evaporable getter 19 is provided between the phosphor films 12 on the front panel 10, and the adjacent two getters are provided on the rear panel 20. At the center of the two electron sources 22, a rectangular evaporable getter 19B is provided.

FIG. 5 is a perspective view showing the structure of the main part of the FED 3 of the third embodiment. The FED 3 is provided with a rectangular evaporable getter 19C on the back panel 20 so as to surround each electron source 22 from four corners, similarly to the FED 2 described above. However, in the case of FED3, 10
A square depression 24a having a depth of about μm is formed, and an evaporable getter 19C is provided at the bottom of the depression 24a.

Thus, the electron source 2 near the depression 24a
When the arc discharge occurs due to the gas discharge in step 2, the inside of the depression 24a is higher in vacuum than the surroundings, so that the gas flows into the depression 24a due to the degree of vacuum gradient, and the arc discharge to the other electron source 22 occurs. Is prevented from spreading.

FIG. 6 is a perspective view showing the internal structure of the FED 4 of the fourth embodiment. The FED 4 has a partition wall 51 having a linear shape in plan view between the phosphor films 12 of the front panel 10, and a partition wall 52 having a lattice shape in plan view surrounding each electron source 22 on the rear panel 20. are doing. These partition walls 51 and 5
2, the vacuum gap 30 is partitioned at equal intervals for each unit light emitting region, and high-definition display without crosstalk (without light emission bleeding) becomes possible.

In the FED 4, the evaporable getter 19D is provided so as to cover the side surface of the partition 51, and the partition 5
An evaporable getter 19E is provided so as to cover the side surface of the second evaporator. These evaporable getters 19D and 19E can be easily formed by arranging the panels 10, 20 and the mask at oblique positions 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. For this reason, the screen display area IA is
It is not necessary to embed a bulk getter by providing a deep groove surrounding the panel, and it is easy to draw out the electrode from the screen display area IA to the end of the panel.

In the above embodiment, the front panel 10
Also, a strip-shaped depression (groove) may be provided by etching the glass plate 11 or the like, and the evaporable getter 19 may be provided therein. Further, the shapes and arrangement positions of the evaporable 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 evaporable getter 19 may be provided so as to cover the inner surface except for the fluorescent film 12.

In the above-described embodiment, the panel sealing can be performed by another method 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 base of the rear panel 20, a conductive layer serving as the cathode electrode 23 is formed by impurity diffusion, and then the conical emitter 25 can be formed by pattern etching of silicon.

In the above-described embodiment, if an evaporative getter is provided on the electron emission surface of the emitter 25, gas is not released and only adsorption is performed, so that field emission noise due to gas attachment / detachment is reduced. In addition, the number of triggers (triggers) of arc discharge is reduced, and the device performance can be improved.

[0046]

According to the first or second aspect of the present invention,
Since the getter is arranged in the screen display area where gas emission is likely to occur during use, gas diffusion is suppressed as much as possible, a high vacuum state is maintained, and the display can be stabilized.

[0047]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an FED according to a first embodiment.

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

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

FIG. 4 is a plan view schematically showing a configuration of an FED according to a second embodiment.

FIG. 5 is a perspective view illustrating a structure of a main part of an FED according to a third embodiment.

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

[Explanation of symbols]

 1, 2, 3, 4 FED (flat display device) 12 phosphor film 10 front panel 20 rear panel 25 emitter (field emission cathode) 30 gap (vacuum gap) IA screen display area 19 19B-E evaporation type getter 24a depression 51, 52 partition

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-100242 (JP, A) JP-A-4-289640 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 31/12 H01J 29/94

Claims (2)

(57) [Claims] 1. A front panel having a fluorescent film and a rear panel having a plurality of field emission cathodes for screen display for selectively exciting the fluorescent film are interposed through a vacuum gap. A flat display device having a structure in which the size of the vacuum gap is locally increased in a screen display area in which the field emission cathode is arranged.
Having an evaporable getter material at the bottom of the depression.
A flat display device, comprising a getter attached to the display device. 2. A front panel having a fluorescent film and said fluorescent panel.
Multiple field emission for screen display to selectively excite optical film
The panel on the back side with the output cathode is connected via a vacuum gap.
A flat display device having a structure opposing to the first display device, wherein a partition partitioning the vacuum gap is provided in the screen display area.
Then, the evaporation type getter material is evaporated on the side surface of the partition wall to be covered.
Characterized by being provided with a getter
Bit-shaped display device.