JPH01112634A - Manufacture of flashing discharge tube - Google Patents

Abstract

PURPOSE:To enhance the durability and starting characteristics and accomplish mass production by arranging a manufacturing process in which the heat generated when cathode and anode are hot sealed to a glass pipe, does not give adversely affect the an easy-to-emit electron substance. CONSTITUTION:At No.1 stage of manufacturing process, a cathode 11 equipped with a sintered substance 15 of mase metal is hot sealed to one end of a glass pipe 16 through a bead 13. When the heat of hot sealing has gone out in No.2 stage, an aqueous solution 24 of an electron easy-to-emit substance is poured to the sintered substance 15 for impregnation by the use of an injection tool 23 in such a way as not splashing on the inside of the glass pipe 16. At No.3 stage, the sealed cathode and glass pipe are dried. At No.4 stage, rare gas is encapsulated in the glass pipe 16, and an anode 12 is hot sealed to the other end of the glass pipe 16 through a bead 14. Thus the easy-to-emit electron substance is held active to enable mass production.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method of manufacturing a flash discharge tube used as a light source of a flash light emitting device.

``Prior Art'' As is widely known as a lighting device for photography, a flash light emitting device is equipped with a flash discharge tube as a light source, and this flash discharge tube discharges electrical energy that has been previously stored in a main capacitor. It is designed to emit flash light.

Recently, with the increase in the number of flash emitting devices built into cameras, there has been a demand for miniaturization of device components, and development efforts are underway to miniaturize flash discharge tubes and increase light output.

This type of flash discharge tube is manufactured as shown in FIGS. 2(a) to 2(e).

Figure 2 (a) shows the connecting wire 1 for configuring the cathode and anode.
1.12, and the front portions 11a and 12a of these connecting lead-in wires 11 and 12 are made of tungsten material.

Other parts are made of nickel material.

As shown in FIG. 2(b), beads 13, 14 are fitted into each of the connecting wires 11, 12, and the connecting wires 11, 12 are fitted with beads 13, 14.
As shown in FIG. 2(c), the sintered body 15 is crimped. This sintered body 15 has a structure in which a sintered base metal is impregnated with an electron-emitting radioactive substance, and the base metal is titanium (T), which is a group 4 titanium group element.
i), zirconium (Zr), niobium (Nb), which is a group 5 vanadine group, tartan (Ta), tungsten (W), which is a group 6 chromium group, and nickel (N), which is a group S iron group.
i) etc. are used independently or in combination. Such a base metal material is preferably one that is inexpensive and has a large high melting point gas adsorption action (getter action).

Cesium oxide, which has the lowest work function, is used as the above-mentioned electron-emissive substance, and generally, a sintered body of the base metal is impregnated with an aqueous solution of cesium chromate (CS2CrO4) and dried.

The above-mentioned sintered body 15 is extremely important in lowering the starting characteristics of the flash discharge tube and increasing its durability, but since it is difficult to handle, various methods are required to attach the cathode to the glass pipe 16. Measures are being taken. In other words, high-temperature impurity gas (
This is to prevent the sintered body 15 from losing its active state due to the influence of cesium chromate (H2O, Go, etc.). In addition,
The glass pipe 16 is made of borosilicate glass, quartz glass, or the like.

Therefore, regarding the anode, as shown in Figure 2(d),
The bead 14 of the longitudinally grooved wire 12 and one end of the glass pipe 16 are heat-welded and sealed prior to attaching the cathode.

The cathode is attached using the means shown in FIGS. 3 to 5.

The means shown in FIG.
The vertically grooved wire 11 provided with the sintered body 15 is inserted from the other end side of the glass pipe 16 in xenon gas at a pressure of about 500 mm, and the other end of the pipe 16 is sealed.

Next, while cooling the anode side by placing it in liquid nitrogen 17,
The beads 13 and a part of the glass pipe 16 are heated and welded using a burner to seal the cathode.

Cut out the extended portion 16a of the glass pipe 16.

According to this means, it is possible to suppress the decomposition of cesium chromate by the cooling effect of liquid nitrogen 17.

The means shown in FIG. 4 involves, after sealing the anode, inserting the vertically grooved wire 11 provided with the sintered body 15 into the other end of the glass pipe 16 and standing it up in the assembly jig 18. The jig 18 is placed in a container 19 and sealed. Subsequently, after filling the container 19 with xenon gas of 1 atm or more, the assembly jig 18 having a heater function is attached to the induction heating coil 2.
0, and the cathode is sealed. In this method, the cathode becomes red hot under the influence of induction heating, and the cesium chromate is thermally decomposed and scattered as vapor, and does not remain in the sintered body 15.
Since the sealing time is short, some of the vapor of cesium chromate remains inside the glass pipe 16.

In the means shown in FIG. 5, after the anode is sealed, the vertically grooved wire 11 provided with the sintered body 15 is inserted into the other end of the glass pipe 16 to stand up on the assembly jig 21.

This assembly jig 21 is placed in a high-pressure tank 22, and the cathode is sealed by functioning as a heater in xenon gas filled in the high-pressure tank 22 at a pressure of 1 atmosphere or more.

Since this means takes a longer heating time than the means shown in FIG. 3, cesium chromate is more likely to diffuse.

The cathode sealed as above is the bead 13 and the glass pipe 1.
6 and the other end thereof are heat-welded as shown in FIG. 2(c).

``Problem to be solved by the invention'' In order to manufacture a compact flash discharge tube with high light output, the arc length is long and the gas pressure is high, and it is necessary to prevent the starting characteristics from increasing. It was necessary to keep the cesium oxide in a good active state.

In order to increase the arc length, it is necessary to shorten the sealing dimensions as much as possible, and when sealing heating is performed, it is necessary to gradually raise and cool the temperature over time.

In conventional manufacturing methods, the decomposition temperature of the electron-emissive material is lower than the sealing temperature, so in order to reduce the thermal influence that occurs during sealing, the sealing time should be shortened as much as possible, or the sealing part and cathode should be It was necessary to increase the size of the sealing part to eliminate the thermal influence that occurs during sealing heating, making it difficult to shorten the sealing size and the dimensions of the sealing part and the cathode.

In the case of the first conventional example shown in FIG. 3, cathode sealing is possible without decomposing the cesium chromate as a result of cooling with liquid nitrogen 17, but since the sealing is performed using a burner, distortion remains and the sealing The dimensions become long, making it difficult to downsize, and in addition, the activation state of cesium chromate deteriorates due to the influence of impure gases caused by heating.

Furthermore, since sealing is performed using a burner, not only is production efficiency low, but the glass pipe 16 is long and liquid nitrogen 17 is used, resulting in a high-cost product.

In the case of the second conventional example shown in Fig. 4, it is possible to seal approximately 4 to 10 cathodes in one sealing action, and the sealing dimensions of the cathodes are smaller than those of the method shown in Fig. 3. Although it is advantageous because the arc length can be made shorter, the product has poor durability because cesium chromate does not remain in the sintered body 15.

Therefore, it is necessary to increase the distance between the sintered body 15 and the cathode sealing part.

In the case of the third conventional example shown in Fig. 5, 500 to 600 wires can be cathode-sealed in one sealing operation, and it also has less sealing distortion and is the most suitable method for mass production. Since the heating time is longer than in the methods shown in FIGS. 3 and 4, the least amount of cesium chromate remains in the sintered body 15, resulting in a product with high starting characteristics and poor durability.

"Means for Solving Problems" The present invention has been developed in view of the above-mentioned problems.

In the method for manufacturing a flash discharge tube according to the present invention, first, as a first step, a cathode provided with a sintered body of a base metal is sealed to one end of a glass pipe.

As a second step, an aqueous solution of an electron-emitting radioactive substance is dripped onto the sintered body from the other end of the glass pipe.

As a third step, the cathode and glass pipe sealed as described above are dried.

As a fourth step, after filling the rare gas, an anode is sealed to the other end of the glass pipe.

"Example" Next, an embodiment of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(d) are diagrams showing the manufacturing process of a flash discharge tube.

The sintered body 15 of the base metal is crimped onto the vertically grooved wire 11 without being impregnated with cesium chromate.

The cathode thus configured is inserted into one end of the glass pipe 16, and the beads 13 and one end of the pipe are heat welded and sealed.

As described above, the sealed cathode sintered body 15 is shown in FIG.
), insert an injection device 23 such as a dispenser into the other end of the glass pipe 16, and insert the injection device 23 into the glass pipe 16.
Drop an appropriate amount of cesium chromate 24 from 3.

Subsequently, as shown in FIG. 1(c), the glass pipe 16 with the cathode sealed thereon is sufficiently vacuum-dried to remove moisture.

Next, the vertically grooved wire 12 is inserted from the other end of the glass pipe 16, and the other end of the pipe 16 and the bead 14 are welded together by heating, thereby sealing the anode as shown in FIG. 1(d).

If carried out as described above, cesium chromate is not impregnated into the sintered body 15 during cathode sealing, so that this cesium will not be affected by impurity gas generated by heating for cathode sealing. There is no.

Further, by using the illustrated elongated injection device 23, it is possible to impregnate the sintered body 15 with cesium chromate without adhering it to the inner surface of the glass pipe 16.

When sealing the anode, there is a predetermined distance between the heat-welded portion and the cathode, so impurity gas generated by this heating has little effect on the cesium chromate in the sintered body 15.

"Effects of the Invention" As described above, in the manufacturing method according to the present invention, before impregnating the sintered body with the electron-emissive substance, the cathode is sealed, and
After that, the sintered body is impregnated with an appropriate amount of electron-emissive material, and the anode is sealed at a position protruding from the sintered body, so that the impurity gas generated by heat sealing of the cathode and anode becomes electron-emissive. Since it has almost no effect on the substance, cesium can be reliably left in an active state, and there is no influence from impurity gases, it is possible to mass produce flash discharge tubes with excellent durability and starting characteristics, and the sealing dimensions and cathode It is possible to manufacture a flash discharge tube with a long arc length by shortening the dimensions of the sealed part, increasing the light output compared to conventional products.In addition, by designing the arc length to be the same as conventional products, the flash discharge tube can be made smaller. becomes possible.

In particular, in the case of a batch method in which 500 to 600 pieces are sealed at -degrees, the sealing time can be extended, resulting in less uneven sealing and high productivity.

[Brief explanation of the drawing]

Figures 1(a) to (d) are diagrams showing the manufacturing process of a flashlight discharge tube according to an embodiment of the present invention, and Figures 2(a) to (e) are diagrams showing the manufacturing process of a conventional flashlight discharge tube. The figures shown, FIGS. 3 to 5, are simplified diagrams showing conventional means of cathodic sealing. 11.12... Vertical groove line 13.14... Beads 15... Sintered body 16... Glass pipe 23... Injection device 24... Cesium chromate 11FIA ( a) (b)
(C) (d) Second
Figure (d) (e) Figure 3

Claims (1)

[Claims] After sealing a cathode with a sintered body of the base metal to one end of a glass pipe, an aqueous solution of an electron-emissive substance is dripped onto the sintered body from the other end of the glass pipe, and then the cathode is sealed. and a method for manufacturing a flash discharge tube, which comprises drying the glass pipe, filling it with a rare gas, and sealing an anode at the other end of the glass pipe.