JP2002343233A - Evaporative getter and electron tube provided with evaporative getter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a getter, comprising only BaAl alloy, MgAl alloy or the like of Ba, Mg, or the like with gas absorbing power and which can be flashed, without containing additional metal such as Ni, and easily attach the getter without using a container for filling getter material by machining the getter material into a predetermined shape through press molding. SOLUTION: BaAl alloy, MgAl alloy or the like which does not contain added metals such as Ni is machined into a discoidal, elliptical or rectangular tabular body by press molding, and such a getter is attached in an interior of an electron tube, such as a fluorescent character display tube by metal wire, frit glass or the like. The getter is flashed by laser beam heating, and a getter mirror film is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporable getter and an electron tube such as a fluorescent display tube provided with the evaporable getter.

[0002]

2. Description of the Related Art A conventional electron tube such as a fluorescent display tube has a getter. The getter includes an evaporable getter and a non-evaporable getter. The evaporable getter has a vapor pressure of about 10 ^-1 at about 1,000 ° C. in terms of ease of evaporation.
の も の 1 Torr is required. For this reason, metals such as Ba and Mg are used in conventional getters in consideration of ease of evaporation and gas absorption capacity. Those B
Since metals such as a and Mg are easily oxidized in the air, generally, alloys of these metals stable in the air, for example, Ba and A
1, alloys of Mg and Al (generally BaAl alloys, MgAl
Alloys), and Ni, T
A mixture of additive metals such as i, Fe, and Zr at a predetermined ratio is used as a getter material. For example, Ba
A BaAl ₄ alloy is used as the Al alloy, and a mixture of Ni powder and Ni powder in a ratio of about 1: 1 is used. BaAl ₄ alloy has a flash temperature of about 1,100.
° C, but flashes easily when Ni powder is added. The getter obtained by mixing the additive metal powder such as Ni with the BaAl ₄ alloy powder flashes when heated by high-frequency induction heating, electric resistance heating, laser light heating, etc., and the evaporated Ba particles are scattered to form the getter mirror film. Form. At this time, when the BaAl ₄ alloy getter is heated by high frequency induction heating or the like, first, the additive metal such as Ni
Reacts with to generate high reaction heat. The reaction heat is added to main heating such as high-frequency induction heating to further heat the getter, so that the heating temperature of the getter rises and the getter flashes. That is, the getter in which the BaAl ₄ alloy powder is mixed with the additive metal powder such as Ni flashes due to the combination of the main heating such as high-frequency induction heating and the reaction heat of Al and Ni. Therefore, an additive metal such as Ni is an essential component for flashing of a BaAl ₄ alloy getter. (See, for example, JP-A-2-177234.)

FIGS. 4 and 5 are cross-sectional views of a conventional fluorescent display tube to which a getter is attached. First, in the case of FIG. 4, a spacer 53 having an opening 531 is arranged between the glass substrate 51 and the getter holding member 54, and a getter 55 is arranged on the getter holding member 54 in the opening 531. I have. The getter holding member 54 has a number of slits 541 formed therein, and communicates with the vacuum chamber 56 having the anode and the like of the fluorescent display tube through the slits 541.
52 is a side plate. The getter 55 is shown in FIG.
As shown in (b), a small iron ring-shaped container 551 plated with Ni is filled with a getter material obtained by mixing BaAl ₄ alloy powder and Ni powder at a ratio of 1: 1. Instead of using the iron ring-shaped container 551, a number of through holes are formed between the spacer 53 and the getter holding member 54, and a Ni-plated 426 alloy plate is provided. The getter is provided on the 426 alloy plate. There is also a thin film-like getter formed of a material. The getter 55 is flashed by a laser beam irradiated from the direction of arrow L. (See, for example, the above-mentioned JP-A-2-177234.)

In the case of FIG. 5, a getter 64 is fixed to a holding member 63 attached to a side plate 62. Getter 64
Is the same as the getter of FIG. 4B. The getter 64 is flashed by a laser beam emitted from the direction of the arrow L. (See, for example, JP-A-4-315740.)

[0005]

SUMMARY OF THE INVENTION Since an additive metal such as Ni contained in a conventional getter is easily oxidized in the atmosphere,
It is difficult to fire in air. To perform atmospheric baking, getters are coated with boron oxide to provide antioxidant means,
It is necessary to use a so-called flutterable getter. Therefore, the cost of the getter increases, and the gas absorbing ability of the getter decreases due to boron oxide.

The additive metal such as getter Ni is BaAl.
It is a component necessary for generating reaction heat by reacting with Al such as an alloy, and is not a component directly contributing to the original function of the getter, that is, the gas absorption in a vacuum vessel such as a fluorescent display tube.
Therefore, in the case of a getter in which a BaAl ₄ alloy and Ni are mixed at a ratio of 1: 1, half of the components constituting the getter are components that do not contribute to gas absorption. The getter therefore
Additive metal such as Ni increases the size, occupies a larger space for the getter, and reduces the thickness of electron tubes such as fluorescent display tubes.
This is an obstacle to miniaturization. In addition, the cost of the getter increases due to an additional metal such as Ni.

The conventional getter requires a container for filling the getter material, a getter holding bracket, a holding member, a spacer, and the like. However, these require a large mounting space for the getter and reduce the size of the electron tube such as a fluorescent display tube. It becomes an obstacle to thinning and thinning. In addition, the cost of processing the containers and holding fittings is high, and the mounting operation of the getter is complicated, so that the cost of an electron tube such as a fluorescent display tube is high. Although the thin film getter has a small thickness, it requires an expensive vapor deposition device and patterning of the getter, so that the cost of the fluorescent display tube and the like increases, and the getter is formed at a place other than a flat plate such as a substrate. It is difficult. Further, since the thin film-like getter is thin, in order to mount a sufficient amount of getter material necessary for gas absorption, the getter arrangement area must be increased. Therefore, the space occupied by the getter increases.

[0008] In view of these points, the invention of the present application does not include an additive metal such as Ni or the like, and includes a metal having a gas absorbing ability such as Ba and Mg, or an alloy thereof (BaAl alloy, MgAl alloy or the like) alone. To provide a volatile getter, to provide a flashable evaporable getter by means of local heating using light energy such as laser light and infrared light, and to provide an evaporable getter having a shape that can be easily mounted. Aim.

[0009]

The getter of the present invention comprises:
It is made of a metal or an alloy of the metal having a gas absorbing ability,
It is an evaporable getter that does not contain an additional metal for generating heat of reaction. The getter of the present invention is an evaporable getter for heating light energy, which is made of a metal having an ability to absorb gas or an alloy of the metal and does not contain an additional metal for generating reaction heat.
The getter of the present invention is an evaporable getter for heating light energy, which is made of a BaAl alloy and does not contain an additional metal for generating reaction heat. In the getter of the present invention, each of the getters is processed into a predetermined shape by press molding. The electron tube of the present invention has any one of the getters. The fluorescent display tube of the present invention is provided with any of the getters. In the electron tube of the present invention, one of the getters is flashed by light energy heating to form a getter mirror film. In the fluorescent display tube of the present invention, one of the getters is flashed by light energy heating to form a getter mirror film.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An evaporable getter according to the present embodiment is a BaAl alloy having a gas absorbing ability, for example, a BaAl alloy.
₄ and does not include additional metals such as Ni, Fe, Ti, and Zr. Further, the evaporable getter of the present embodiment flashes by heating with laser light. The inventor of the present application
Experiments were repeated on various types of evaporable getters made of a material obtained by mixing a conventionally used BaAl ₄ alloy powder with a Ni powder at a ratio of 1: 1 using various heating means commonly used for flashing the getters. The powder is
Conventionally, it was considered an indispensable component in the getter flash, but in the case of laser light heating,
Turned out to be unnecessary. That is, it was found that the BaAl ₄ alloy getter flashes by laser light heating even when the Ni powder is not mixed with the BaAl ₄ alloy powder.

In this embodiment, BaAl ₄ alloy powder is press-molded to have a diameter of 2.0 mm and a thickness of 0.3 m.
m of a plate-like getter. The getter was adhered to one of the substrates constituting the vacuum vessel of the fluorescent display tube, and the getter mirror film was formed on the other substrate by flashing by heating with laser light. The distance between both substrates is
1.4mm, laser (YAG) output is 0.25-
2.5J, the laser beam diameter was set to 0.4 mm, and the distance between the laser and the getter was set to 1.2 mm.

When the above-mentioned getter was fixed by welding and heated with laser beams having outputs of 0.25 J and 2.5 J,
Getter mirror films having a diameter of 3.0 mm and a diameter of 5.0 mm, respectively, were formed. Even when the getter was fixed with frit glass and heated under the same conditions as above, a getter mirror film similar to that in the case of welding was formed.

Since the BaAl ₄ alloy getter of the present embodiment does not contain Ni, it can be fired in the air and the manufacture of the fluorescent display tube is facilitated. Also, the BaA of the present embodiment
l ₄ alloy getters, do not contain Ni, it has the same gas absorption capacity to the conventional getter in the size of a conventional half. Therefore, the space occupied by the BaAl ₄ alloy getter of the present embodiment is reduced, and the cost is also reduced.

The present embodiment has been described BaAl ₄ alloy getter is not limited to the BaAl ₄ alloy, MGA
Any getter made of an alloy of a metal having a gas absorbing ability such as an alloy may be used. Although it is difficult to handle in the atmosphere, Ba,
A getter made of a simple metal such as Mg having a gas absorbing ability may be used. Although the heating of the getter in this embodiment has been described with respect to heating by laser light, the invention is not limited to laser light, and light energy such as infrared light may be used.

FIG. 1 is a perspective view of a getter according to an embodiment of the present invention. The getter of FIG. 1 uses BaAl ₄ alloy powder as a material, and FIG.
1 (b) is formed into an elliptical plate, FIG. 1 (c) is formed into a rectangular plate, and FIG. 1 (d) is formed into a linear shape.
The shape is not limited to these, and may be a polygon. The cross section of the linear getter may be a polygon or a circle. The shape, size, and thickness of the getter can be selected according to the place where the getter is to be arranged, and getters of various shapes, sizes, and thicknesses can be combined and arranged in one fluorescent display tube. Since the getter of the present embodiment is processed by press molding, it does not require a container for filling the getter material, and can be easily attached as described later.

FIG. 2 is a perspective view of a substrate of a fluorescent display tube to which a getter according to an embodiment of the present invention is attached. FIG.
(A) is an example in which a disk-shaped getter 121 is attached to the substrate 11 by an adhesive 131 such as frit glass.
FIG. 2B shows an example in which a rectangular plate-like getter 122 is held by a claw member 132 fixed to the substrate 11.
The shape of the getter is not limited to these. In the case of FIG. 2, since the getters 121 and 122 are processed by press molding, the getters themselves can be directly fixed or held, and the means for attaching the getters is simplified.

FIG. 3 is a perspective view of a substrate of a fluorescent display tube to which the getter according to the embodiment of the present invention is attached by an aluminum wire. FIG. 3A shows a disk-shaped getter 2.
21 is attached to the substrate 21 by an aluminum wire 231, the aluminum wire 231 is engaged with the concave portion 2211 of the getter 221, and both ends 25 of the aluminum wire 231 are
1 is ultrasonically welded (ultrasonic wire bonding) to an aluminum layer 241 previously formed on the substrate 21.
I have. In the case of FIG.
Since the getter 221 can be attached or held only by fixing both ends of the getter 1, the means for attaching the getter is simplified.

FIG. 3B shows an example in which a disk-shaped getter 222 having an opening 2221 is attached to the substrate 21 by an aluminum wire 232. Both ends 252 of the aluminum wire 232 are previously covered on the substrate 21. It is ultrasonically welded to the aluminum layer 242 formed. In the case of FIG. 3B, one end of the aluminum wire 232 is connected to the opening 222.
1, the getter 222 does not move even if a recess corresponding to the recess 2211 in FIG. 3A is not formed. Also, the space for mounting the getter 222 is reduced.

FIG. 3C shows a getter 223 with an aluminum wire 233 attached to a disk-shaped getter 223.
Is attached to the substrate 21, and both ends 253 of the aluminum wire 233 are ultrasonically welded to the aluminum layer 243 previously formed on the substrate 21. In the case of FIG. 3C, since there is a space between the substrate 21 and the getter 223, a getter film can be formed on the substrate 21, and when the getter 223 is flashed, the Ba particles evaporated are aluminum. Since it does not scatter outside the line 233, the getter 223 can be arranged close to the display area. Therefore, the space required for mounting the getter can be reduced. Further, since a getter mirror film can be formed on the substrate facing the substrate 21 as required, a getter mirror film can be formed on both substrates with one getter.

The aluminum layers 241 to 243 may be formed so as to cover not only a portion where the aluminum wires 231 to 233 are mounted but also a wide area of the substrate 21. The aluminum layers 241 to 243 can be formed by vapor deposition, sputtering, plating, or the like.

In the case of FIG. 3, the getters 221 to 223
Those having a diameter of 2.0 mm and a thickness of 0.3 mm, the aluminum wires 221 to 223 having a diameter of 0.2 mm, and the aluminum thin films 241 to 243 having a thickness of 1.2 μm
m. The welding of the aluminum wires 231 to 233 is not limited to the ultrasonic welding.
When 243 is a thin film, aluminum layers 241 to 24
Taking into account the damage caused by heating in No. 3, ultrasonic welding is suitable.

The aluminum wires 231 to 233 and the aluminum layers 241 to 243 are not limited to aluminum.
Other metals, for example, Au, Ag, Cu, etc. may be used, and the aluminum wires 231 to 233 and the aluminum layers 241 to 243 are not limited to the same kind of metal but may be different kinds of metals. Further, the shapes of the getters 221 to 223 are not limited to those shown in FIG. In the case of FIG. 3, getter 2
The attachment or holding of 21 to 223 is performed by using the aluminum wire 23
No. 1 to 233 need only be welded, and no expensive container for filling the getter material or expensive getter mounting means is required, so that the cost of the getter and its mounting means can be reduced, and the work of mounting the getter is simplified.

In each of the above embodiments, the example in which the getter is attached to the substrate has been described. However, not only the substrate but also components such as the filament holding member (filament anchor, filament support, etc.) and the grid of the fluorescent display tube can be easily applied. Can be mounted on Although the above embodiments have been described with respect to the fluorescent display tube, the present invention is not limited to the fluorescent display tube, but may be a fluorescent light emitting print head for performing optical writing on a photosensitive member, a display tube other than the fluorescent display tube, and other electronic tubes. Good.

[0024]

The getter according to the present invention is composed of only a metal having an ability to absorb gas such as Ba or Mg, or an alloy of those metals, and does not contain an additional metal such as Ni. Therefore, the getter is coated with boron oxide. Air baking can be performed without performing. Therefore, the manufacturing process of an electron tube such as a fluorescent display tube is simplified. Further, the getter of the present invention does not require a coating of an additive metal such as Ni or boron oxide, so that the cost of the getter can be reduced, and the gas absorbing ability of the getter due to boron oxide does not decrease. Since the getter of the present invention does not contain an additive metal such as Ni, the size is small, and the electron tube such as a fluorescent display tube to which the getter is attached is also small and thin.

Since the getter of the present invention is processed into a predetermined shape by press molding, it can be manufactured in an arbitrary shape, size and thickness depending on the place where the getter is mounted. Since a getter having a size and a thickness can be used in combination, the getter can be attached by effectively utilizing the space inside the electron tube such as a fluorescent display tube. Further, there is no restriction on the mounting place unlike the thin film getter. Further, the getter of the present invention does not require a container for filling the getter material and expensive mounting means for the getter, so that the cost of the getter and its mounting means can be reduced, and an expensive vapor deposition device or getter such as a thin film getter can be obtained. Since patterning is not required, the cost of an electron tube such as a fluorescent display tube can be reduced. According to the present invention, the getter can be attached or held only by welding the metal wire, and the getter can be directly attached by an adhesive or the like without using the metal wire, so that the operation of attaching the getter is simplified.

[Brief description of the drawings]

FIG. 1 is a perspective view of a getter according to an embodiment of the present invention.

FIG. 2 is a perspective view of a substrate of the fluorescent display tube to which a getter is attached by first attaching means according to the embodiment of the present invention.

FIG. 3 is a perspective view of a substrate of a fluorescent display tube to which a getter is attached by second attaching means according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a fluorescent display tube to which a conventional getter is attached.

FIG. 5 is a sectional view of another fluorescent display tube to which a conventional getter is attached.

[Explanation of symbols]

11, 21 fluorescent display tube substrate 121, 122, 221, 222, 223 getter 131 frit glass 132 claw member 2211 concave portion 2221 opening 231, 232, 233 aluminum wire 241, 242, 243 aluminum thin film 251, 252, 253 aluminum wire End welds

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Satoru Ishige 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Industry Co., Ltd.In-house F-term (reference) 4K018 AA15 CA11 KA32 5C032 AA06 JJ07 JJ10 5C035 JJ09 JJ11 JJ19 5C036 EE14 EE19 EF01 EF02 EF05 EF07 EF08 EG02 EG50 EH11

Claims (8)

[Claims] 1. An evaporable getter comprising a metal having a gas absorbing ability or an alloy of the metal and not containing an additional metal for generating heat of reaction. 2. An evaporable getter for heating light energy, comprising a metal having an ability to absorb gas or an alloy of the metal and containing no additional metal for generating reaction heat. 3. An evaporable getter for heating light energy, comprising a BaAl alloy and containing no additional metal for generating reaction heat. 4. An evaporable getter, wherein only the material of the evaporable getter according to claim 1 is processed into a predetermined shape by press molding. 5. An electron tube to which the evaporable getter according to claim 1 is attached. 6. A fluorescent display tube provided with the evaporable getter according to claim 1. 7. An electron tube in which the getter mirror film is formed by flashing the evaporable getter according to claim 1 by light energy heating. 8. A fluorescent display tube in which a getter mirror film is formed by flashing the evaporable getter according to claim 1 by light energy heating.