JPH0718123Y2 - Flash discharge tube - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flash discharge tube in which positive and negative electrodes are hermetically sealed at both ends of a glass tube in which a rare gas such as xenon is sealed.

2. Description of the Related Art As a light source for a photographic strobe device, a flash discharge tube in which a rare gas such as xenon is enclosed in a glass tube and positive and negative electrodes are hermetically sealed at both ends is used.

When used as a light source for a photographic strobe device or the like, a flash discharge tube is required to have a life that can sufficiently withstand a light emitting operation of about 5,000 times. Therefore, in the conventional flash discharge tube, a hard glass is adopted as the glass tube, and the lead glass wire which is hermetically sealed with the hard glass and supports the anode or the cathode has a high boiling point and a hard glass having a thermal expansion coefficient. It was common to use tungsten, which is similar to

On the other hand, in recent years, a low-priced simple camera, which is a so-called disposable camera that is integrated with a film unit and does not exchange the film, has been put into practical use, and recently, a built-in strobe device has also been proposed. When a flash discharge tube is used as a light source of a built-in flash device of such a disposable camera, it is considered that the function of withstanding 5000 times of light emission is too high in performance. In other words, with a disposable camera, if the film that is built-in is used up, you cannot shoot any more images.Therefore, the built-in flash unit can emit light stably for about 100 times, including the manufacturing test. It's enough if you can, and you don't need to fire 5000 times.

For this reason, using the conventional high-performance flash discharge tube for a disposable camera increases the cost of the disposable camera, which is extremely strongly required to be low in cost. For example, the high melting point tungsten electrode used for extending the life is expensive, and since the soldering cannot be done directly, the nickel pin for external lead wire soldering is welded and expensive. However, since such a flash discharge tube is used even when the life is short as described above, it has been a factor in increasing the cost.

On the other hand, a flash discharge tube that does not use tungsten as an electrode lead has been known (for example, Japanese Patent Publication No. 61-57653). This prevents adverse effects due to the difference in thermal expansion coefficient between the glass tube material and the electrode lead material, and simplifies the manufacturing to reduce the cost.

This flash discharge tube is, as shown in FIG. 2, provided on both ends of a glass tube 1 with intermediate bodies 2 and 3 formed by sintering glass powder,
A structure in which electrode leads 4 and 5 made of at least one of nickel, nickel-iron alloy, and nickel-iron-cobalt alloy are hermetically sealed, and the anode member A and the cathode member K are supported at the tips of the electrode leads 4 and 5. Is. A rare gas such as xenon is enclosed in the glass tube 1, and one intermediate body 2 is hermetically bonded to the glass tube 1 by a glass brazing ring 6.
The other intermediate 3 is made of, for example, an organic adhesive and is made of glass
Is airtightly combined with. Furthermore, one intermediate 2 is 2
It consists of two coaxially superposed layers 2a, 2b, the other intermediate body 3 of which is embedded with a metal lead G which serves as a firing electrode or a getter.

Since this flash discharge tube uses the intermediate bodies 2 and 3, it is possible to avoid the glass blowing work which is expensive in the manufacturing process, and the intermediate bodies 2 and 3 themselves can be mechanically manufactured at low cost. Further, since the intermediate bodies 2 and 3 compensate for the generation of the thermal stress due to the difference in the thermal expansion coefficient between the intermediate body 2 and the glass tube 1, the electrode leads 4 and 5 are lower in cost than tungsten, nickel, a nickel-iron alloy, Metals such as nickel, iron, and cobalt alloys can be used, and flash discharge tubes can be manufactured at low cost.

The problem to be solved by the invention is that the flash discharge tube as shown in FIG. 2 can be manufactured at a lower cost than the conventional one by adopting the intermediate body, but in terms of its life, it is still delayed. 5,000
Consideration is given to sufficiently withstand the light emitting operation about once.
That is, as the electrodes, those in which the anode member A and the cathode member K are provided at the tips of the electrode leads 4 and 5 made of nickel or the like having a melting point lower than that of a high melting point metal such as tungsten are used. However, the cost is still high as the one used when the short life is sufficient as described above.

In addition, when the life is short, the use of an intermediate product also causes a cost increase when considering the preparation and manufacturing costs of the intermediate product, and further, a glass brazing ring or the like is used for hermetically sealing the glass tube. Is also a factor of cost increase.

The present invention solves the above-mentioned conventional problems, and provides a flash discharge tube suitable for use in a flash device of a disposable camera and the like, which has a short life but can be obtained at low cost. To aim.

Means for Solving the Problems A flash discharge tube according to the present invention comprises a hard glass tube which serves as an envelope and is filled with a rare gas, and a first Kovar metal which is arranged at one end of the hard glass tube and serves as an anode. An electrode, a second Kovar metal electrode that supports the cathode member at the tip and is arranged at the other end of the hard glass tube, the end of the hard glass tube and the first.
The hard glass tube is hermetically sealed to the second Kovar metal electrode, and the glass bead is made of the same material.

Action The flash discharge tube according to the present invention has the above-mentioned configuration.
With the glass beads welded to the first and second Kovar metal electrodes, and the cathode member supported by the second Kovar metal rod, while enclosing the rare gas in the hard glass tube, the glass bead and the hard glass tube were formed. Can be manufactured by directly air-sealing, and can be configured without using the anode member, the intermediate body, and the air-sealing member of the intermediate body and the glass tube, and can be manufactured easily and at low cost. it can.

Embodiment An embodiment of the flash discharge tube of the present invention will be described below.

1 (a) and 1 (b) are sectional views showing an embodiment of the flash discharge tube according to the present invention, (a) showing a completed state after air-sealing, and (b) showing before air-sealing. Shows the state in the process of being manufactured.

In the method of manufacturing the flash discharge tube, first, the hard glass tube 7 is prepared. On the other hand, a rod-shaped first Kovar (kovar is nickel-iron-cobalt alloy) metal electrode 10 serving as an anode, and a rod-shaped second Kovar metal electrode 11 supporting the cathode member K at its tip are prepared, respectively. Then, glass beads 8 and 9 of the same material as the hard glass tube 7 are welded. First and second Kovar metal electrodes to which the glass beads 8 and 9 are welded
10 and 11 are inserted into both ends of the hard glass tube 7 in a rare gas such as xenon as shown in FIG. 1 (b), and the first Kovar metal electrode 10 is attached to one end of the hard glass tube 7, 2 Kovar metal electrodes 11 are respectively arranged on the other end of the hard glass tube 7, and then both ends of the hard glass tube 7 are heated to melt both the hard glass tube 7 and the glass beads 8 and 9,
The both are directly air-sealed by welding of both to complete a flash discharge tube in which a rare gas is enclosed as shown in FIG. 1 (a).

The first and second Kovar metal electrodes 10 and 11 may be made of Kovar in which the mixing ratio of nickel or the like is appropriately adjusted so that the thermal expansion coefficient thereof has a value extremely similar to that of the hard glass tube 7. .

Further, the glass beads 8 and 9 are made of the same material as the hard glass 7. For example, the same glass tube as the hard glass tube 7 may be sliced into appropriate sizes and welded to predetermined portions of the first and second Kovar metal electrodes 10 and 11.

In the air-sealing work, the hard glass tube 7 and the glass beads 8 are first sealed and then the hard glass tube 7 and the glass beads 9 are placed in an atmosphere of a rare gas such as xenon.
And the like, or the work between the hard glass tube 7 and the glass beads 8 and 9 is performed at the same time in a rare gas atmosphere such as xenon.

As is apparent from FIG. 1 (a), the flash discharge tube produced as described above has the first Kovar metal electrode.
Since 10 is used as an anode as it is, no special anode member is provided, so the number of parts can be reduced and the cost can be obtained. Also, the hard glass tube 7
Since the glass beads 8 and 9 of the same material are used,
There is an advantage that the cost can be reduced in terms of the number of parts and the manufacturing process without requiring a special intermediate.

Since the first Kovar metal electrode 10 is used as the anode as it is, the life is short, but it is sufficient for use in a stroboscopic device of a disposable camera and the like, and the cost performance can be improved.

Effect of the Invention Thus, the flash discharge tube of the present invention uses the Kovar metal which is cheaper than tungsten and can be directly soldered, and uses the first Kovar metal electrode as it is as the anode. Since it is not provided, the number of parts can be reduced and the cost can be reduced.

Further, since the glass beads made of the same material as the hard glass tube are used, there is an advantage that a special intermediate is not required and the cost can be reduced in terms of the number of parts and the manufacturing process.

Therefore, according to the present invention, it is possible to obtain a flash discharge tube having a short life but good cost performance, which is sufficient for use in a flash device of a disposable camera.

[Brief description of drawings]

1 (a) and 1 (b) are sectional views showing an embodiment of the flash discharge tube according to the present invention, and FIG. 2 is a cross section of a conventional flash discharge tube. 7 ... Hard glass tube, 8, 9 ... Glass bead, 10 ... First Kovar metal electrode, 11 ... Second Kovar metal electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manabu Kusumoto 2-995 Nagara Higashi, Kita-ku, Osaka City, Osaka Prefecture West Electric Co., Ltd. 9th 95th West Electric Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A hard glass tube serving as an envelope, in which a rare gas is sealed, a first Kovar metal electrode serving as an anode arranged at one end of the hard glass tube, and a cathode member supported at the tip. A second Kovar metal electrode arranged at the other end of the hard glass tube, and the hard glass tube that hermetically seals the end of the hard glass tube and the first and second Kovar metal electrodes. A flash discharge tube comprising a glass bead of material.