JPH0423377B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a double-end sealed flash discharge tube in which an anode and a cathode are sealed oppositely to each other at both ends of a glass tube, and a method for manufacturing the same.

Prior Art Flash discharge tubes have traditionally been used in various ways as light sources for strobe devices, which are one of the artificial light sources used in photography.In particular, in recent years, so-called cameras with built-in strobes, which integrate the above-mentioned strobe devices with cameras, have also been used. These flash discharge tubes are becoming more common, and there is a demand for compact and high-performance flash discharge tubes.

Therefore, various studies have been made to satisfy the above requirements, and for example, a flash discharge tube as shown in FIG. 5 is disclosed in Japanese Utility Model Application Publication No. 165660/1983.

As is clear from the drawing, such a flash discharge tube has flat end plate portions 2a and 3 at both ends of a glass tube 1.
a and peripheral wall portions 2b and 3b which rise from the outer periphery and whose end portions have a wall thickness smaller than that of the end plate portions 2a and 3a, and further include one of the peripheral wall portions 2b and 3b. A cathode 4 and an anode 5 are provided with power feeding tongues 2c and 3c extending laterally from the inner surface thereof, and projecting into the glass tube 1 at the center of the inner surface thereof.
The metal caps 2 and 3 to which are connected are sealed.

Further, a well-known trigger electrode 6 made of a transparent conductive film is provided on the outer peripheral wall of the glass tube 1 surrounding the arc generation area formed between the cathode 4 and the anode 5.

Furthermore, if you think about the manufacturing method,
Although not detailed in the above proposal, metal caps 2 and 3 with cathodes 4 and anodes 5 welded to them, respectively, and glass tube 1 are prepared, and first, one end of glass tube 1 and one of metal caps 2 or 3 are welded. are welded as shown in the figure by heating and melting the end of the glass tube 1,
Next, in an atmosphere of a desired rare gas such as xenon gas or argon gas, the other end of the glass tube 1 and the metal cap 2 or 3 that was not welded first are heated in the same manner as in the above case. It is believed that the prototype is manufactured by melting and welding, and then completed by applying the well-known trigger electrode 6. It goes without saying that even if the trigger electrode 6 is applied before the metal caps 2 and 3 are welded, the same result can be achieved.

With the above structure, the flash discharge tube disclosed in the above proposal requires a smaller length for the electrode sealing part, and since the metal caps 2 and 3 also serve as power supply lines, the length of the flash discharge tube disclosed in the above proposal is reduced. The ratio of the discharge path length becomes extremely high, which has the effect of being relatively compact. Also,
Due to the difference in thermal expansion coefficient between the glass tube 1 and the metal caps 2 and 3 in the sealing part itself, the wall thickness of the end portions of the peripheral walls 2b and 3b of the metal caps 2 and 3 is Since the wall thickness is smaller than that of the metal cap 2, the small wall thickness deforms following the shrinkage of the glass tube 1, resulting in a significant improvement.In other words, due to the difference in thermal expansion coefficient, the metal cap 2, This also has the effect that the unreasonable force that had previously been generated between the ends of the peripheral walls 2b, 3b of 3 and the welded glass tube 1 is no longer applied, and the risk of cracks occurring in these parts can be extremely reduced. There is.

Problems to be Solved by the Invention As mentioned above, the flash discharge tube disclosed in Japanese Utility Model Application No. 59-165660 can be expected to have the effects of miniaturization and suppression of cracks. In order to ensure reliable sealing between the glass tube 1 and the metal caps 2 and 3, the inner surfaces of the end plates 2a and 3a of the metal caps 2 and 3 and the glass tube 1
Although not disclosed, it seems necessary to apply a light pressing force to the metal cap 2 or 3 in the direction of pressing them against each other when the glass tube 1 is heated and melted.

This is because it takes a certain amount of time to melt the end of the glass tube 1 by heating and naturally achieve the welded state shown in Fig. 5 due to the weight of the glass tube 1 and metal caps 2 and 3. Therefore, there is a risk that the vicinity of the end of the glass tube 1 may be unnecessarily melted and deformed, and impurity gas may be generated from the electrodes, etc., making it extremely difficult to put it into practical use. It is preferable to do this in a short period of time.On the other hand, it is easy to think that applying a light pressing force as described above can obtain the state shown in FIG. 5 in a short period of time.

However, if we consider the electrode sealing process of a flash discharge tube, which is not shown in the drawings but is conventionally extremely common, in which rod-shaped electrodes are sealed at both ends of a glass tube,
Application of the above-mentioned pressing force only makes the sealing process more expensive and complicated.

In other words, it is necessary to prepare a configuration for applying a pressing force, and in addition, with this configuration, if there are variations in the application state of the pressing force, deformation of the glass tube and accompanying variations in discharge path length will occur. Although it can be made smaller, it still has the problem of having to be managed with extremely high precision due to the risk of damage.

The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a flash discharge tube with both ends sealed, which has a simple sealing process and can be miniaturized, and a method for manufacturing the same.

Means for Solving the Problems The flash discharge tube sealed at both ends according to the present invention includes a glass tube as an envelope in which a rare gas is sealed, a pair of metal plates that also serve as electrode leads, and a pair of metal plates that also serve as electrode leads. The electrode rod serving as an anode and the support rod supporting the cathode are welded to each of the electrode rods and the support rod supporting the cathode, and the electric rod is heated and welded to the end portion of the glass tube provided on a part of each of the electrode rod and the support rod. and a support rod at both ends of the glass tube; a cathode fixed near the tip of the support rod; and a trigger consisting of a transparent conductive coating applied to the outer peripheral surface of the glass tube. and an electrode.

Further, the method for manufacturing a flash discharge tube sealed at both ends according to the present invention includes a welding step of welding an electrode rod serving as an anode and a support rod supporting a cathode to each of a pair of metal plates serving as electrode leads; A glass bead member installation step in which a glass bead member having an outer diameter smaller than the inner diameter of a glass tube serving as an envelope is welded or arranged on a part of the support rod, and a cathode is fixed near the tip of the support rod. a cathode fixing step, and a first sealing step of heating and welding one of the glass bead members provided on the electrode rod or support rod to one end of the glass tube and sealing the electrode rod or support rod on the one end. and a glass bead member provided on the electrode rod or support rod that was not heat-welded in the first sealing step to the other end of the glass tube in a predetermined rare gas atmosphere. The method includes a second sealing step of sealing the electrode rod or support rod at the other end, and a trigger electrode forming step of forming a transparent conductive coating that will become a trigger electrode on the outer peripheral surface of the glass tube.

Function The discharge tube sealed at both ends according to the present invention has a glass bead member on the electrode rod and the support rod, and heat-welds the glass bead member and the end of the glass tube as described above, so that the sealing portion can be basically fixed. In this case, the metal plate that also serves as the electrode lead has less influence on the sealing, and the degree of freedom in setting the shape of the metal plate is increased. For example, it is possible to seal both ends with a uniform thickness. The discharge tube can be made smaller in size than a discharge tube using rod-shaped electrodes, and can be provided extremely easily.

Further, the method for manufacturing a discharge tube sealed at both ends according to the present invention includes the glass bead installation step of providing a glass bead member on the electrode rod and the support rod as described above, and heating and welding both ends of the glass tube and the glass bead member. Since the first and second sealing steps are included, the sealing portion can basically be made of glass, and therefore the sealing work can be easily and quickly performed without applying any pressing force. As a result, there is no need for a configuration for applying a pressing force, making it possible to reduce manufacturing costs and stabilize the length of the discharge path.

Embodiment FIG. 1 is a cross-sectional view showing an embodiment of a flash discharge tube sealed at both ends according to the present invention. In the figure, the same numbers as those in FIG. 5 indicate the same functional members.

In FIG. 1, numerals 7 and 8 indicate a pair of metal plates that also serve as electrode leads, and a support rod 9 and an anode 5 for supporting the cathode 4 and facing inward of the glass tube 1 are formed at the center of each inner surface. An electrode rod 10 is provided, for example, by welding.

Although not clearly shown in FIG. 1, 11 and 12 indicate glass bead members that were previously provided on the support rod 9 and the electrode rod 10 and heat-welded to the end of the glass tube 1. In addition, the cathode 4 is connected to the support rod 9
Needless to say, it is fixed by caulking or welding, for example.

As is clear from the above configuration, in the double-end sealed discharge tube according to the present invention, the sealed portions at both ends of the glass tube 1 are connected to the glass tube 1 and the glass bead members 11 and 12.
and a part of the support rod 9 or the electrode rod 10.

Therefore, the sealing operation does not require the application of a pressing force as in the conventional example illustrated in FIG. 5, and only requires heating, making it simple and the manufacturing cost low.

It is also clear from Fig. 1 that metal plates 7 and 8, which also serve as electrode leads, are provided at both ends of the glass tube 1, and therefore the ratio of the discharge path length to the total length is as shown in Fig. 5. It is also clear that the height is the same as in the conventional example, and the size can be relatively reduced.

Furthermore, depending on how the glass bead members 11 and 12 are installed with respect to the support rod 9 and the electrode rod 10, it is possible that the metal plates 7 and 8 and the glass bead members 11 and 12 or the end of the glass tube may be welded together. However, the metal plates 7 and 8 are flat plates without a peripheral wall, and the possibility of cracks occurring due to the difference in coefficient of thermal expansion is far greater than when using a so-called metal cap with a peripheral wall. It has been confirmed that it is small and there is no particular problem, but on the other hand,
From this point of view, the degree of freedom in setting the shape of the metal plates 7 and 8 is increased. For example, as shown in FIG.
This means that it is possible to form a flash discharge tube having a diameter smaller than the outer diameter of the tube, that is, a straight tube shape with no protruding portions and sealed at both ends.

Now, a method for manufacturing a flash discharge tube sealed at both ends according to the present invention will be described below.

FIGS. 2a to 2f are process diagrams showing an embodiment of the method for manufacturing a flash discharge tube sealed at both ends according to the present invention,
As shown in the figure, this embodiment includes the welding process shown in figure a, the glass bead member installation process shown in figure b, the cathode fixing process shown in figure c,
The process includes a first sealing process shown in d of the same figure, a second sealing process shown in e of the same figure, and a trigger electrode forming process shown in f of the same figure.

Each of the above-mentioned steps will be explained below.

First, the welding process shown in FIG.
In this step, the electrode rods 10 are spot welded and fixed to the central part of the metal plate 8 to obtain the combinations X and Y. Note that A in the figure indicates a spot weld.

The glass bead member installation process shown in FIG.
1 and 12, and in this embodiment, the glass bead members 11 and 12 are fitted into parts of the support rods 9 and electrode rods 10 of the combinations X and Y, and then installed by welding. , combination Xa, Ya
Here is an example of how to get .

The cathode fixing step shown in FIG. 2c is a step of fixing the cathode 4 to the combination body Xa consisting of the metal plate 7, support rod 9, etc. obtained through the above-mentioned glass bead member installation step, for example. The example shows an example in which the cathode 4 formed into a cylindrical shape is fixed to the vicinity of the tip of the support rod 9 of the combination Xa by caulking to obtain the combination Xb.
Each of the steps shown in Figure 2 a, b, and c has been explained above, but each of these steps is ultimately combined.
It is sufficient if Xb and Ya are obtained, for example, after the welding process shown in Fig. 2a is followed by the processes shown in Figs. 2b and c,
That is, first, the glass bead members 11 and 12 are installed on the support rod 9 and the electrode rod 10, and the cathode 4 is placed on the support rod 9.
Needless to say, the metal plates 7 and 8 may be welded together after the metal plates 7 and 8 are fixed. In other words, the second
The steps shown in Figures a, b, and c are not limited to the order shown, and can be replaced as appropriate in consideration of workability.

Now, next is the first sealing step shown in FIG. This is a step of heating and welding one end 1a of the glass tube 1 to the end 1a of the glass tube 1 to obtain a tube member T in which the above assembly Ya is sealed to the end 1a of the glass tube 1.

Now, if we think about the heating work mentioned above,
Glass bead member 12 and one end 1a of glass tube 1
In other words, it is sufficient to weld the glasses together, so there is no need to apply a pressing force as in the conventional example shown in Fig. 5, and the heating temperature,
This means that the heating time can be shortened, and considering the possibility of deformation etc. mentioned above, it is clear that this is an extremely preferable and practical heating operation.

Next, a second sealing step shown in FIG. 2e will be performed.

In this step, the glass bead member 11 of the combination Xb obtained in the previous step and the other end 1b of the glass tube 1 of the tube member T are heated and welded in an atmosphere of a desired rare gas, for example, xenon gas 13. This is a step of obtaining a tube member Ta in which the above-mentioned combination Xb is sealed to the end portion 1b of the glass tube 1.

It goes without saying that this second sealing step, like the first sealing step, is an extremely practical task.

Next, the above-mentioned tube member Ta shown in FIG.
A well-known trigger electrode forming process is performed in which a transparent conductive coating is applied to a predetermined area of the outer peripheral surface of the glass tube 1.

In this step, for example, as shown in the figure, the vicinity of both electrodes where it is not necessary to form a trigger electrode is coated with coating members B and C in advance, and a metal solution such as tin is atomized at high temperature to form a glass tube. This is generally carried out by spraying onto the outer peripheral surface that is not coated with one of the coating members B and C.

Finally, by removing the covering members B and C, a flash discharge tube sealed at both ends according to the present invention as shown in FIG. 1 is obtained.

The steps shown in FIG. 2 d to f have been described above, but in this embodiment, the glass bead members 11 and 1 are
2 are welded to the support rod 9 and the electrode rod 10, respectively.As mentioned above, the first and second sealing steps involve sealing the glasses together, and are low-temperature and short-time operations, so they are limited to the order shown in the figure. For example, the glass bead member 11 of the combination Xb and one end 1a of the glass tube 1 are first heat-welded, and then the glass bead member 12 of the combination Ya and the glass tube are welded together in a predetermined rare gas atmosphere. Needless to say, the tube member Ta may be obtained by heat welding the other end portion 1b of the tube member Ta.

Also, regarding the trigger electrode formation process, see the figure f.
Although the embodiment shown in FIG. As shown in Fig. 2, predetermined portions of both ends of the glass tube 1 cut to predetermined dimensions are covered with coating members B' and C', and as explained in Fig. 2 f, a metal solution such as tin is heated to a high temperature. The above-mentioned covering member B′ is made into a mist.
This may be done by spraying onto the outer surface of the glass tube 1 that is not covered with C'. In other words, the trigger electrode forming step may be carried out before the first and second sealing steps. Needless to say. Incidentally, if the trigger electrode forming step is performed before the first and second sealing steps as shown in FIG.
The shape of the glass tube 1 is standardized, and the covering member
The state of coverage of the end of the glass tube 1 by B' and C' is
It is clear that the coating condition can be better than that shown in FIG. f.

Figures 4a to 4f are process diagrams showing other embodiments of the method for manufacturing a discharge tube sealed at both ends according to the present invention, and as described in the figures, the embodiments and contents shown in Figures 2a to 2f are has similar steps, although they are slightly different.

Hereinafter, each process shown in FIGS. 4a to 4f will be briefly explained.

FIG. 4a shows the same welding process as shown in FIG. 2a, in which a support rod 9 and an electrode rod 10 are welded to a pair of metal plates 7 and 8, respectively, to obtain combinations X and Y. .

The step shown in FIG. 4b is a glass bead member installation step and is the same step as in FIG. Glass bead member 11,1
2, simply insert the glass bead members 11, 12
This is the process of setting up and obtaining the combination Xa′, Ya′.

The step shown in FIG. 4c is a cathode fixing step similar to that in FIG. 2c, in which the cathode 4 is fixed to the combination Xa' by caulking or the like to obtain the combination Xb'.

The process shown in Figure 4d is the same as the first step shown in Figure 2d.
As for the sealing process, in this embodiment, as is clear from the figure, the glass bead member 12 of the assembly Ya', the electrode rod 10, and one end 1a of the glass tube 1 are simultaneously heat-welded to form the tube member T. This is the process of obtaining.

For this reason, higher temperature heating is required than in the embodiment previously explained with reference to FIG. The possibility of a crack occurring is small and does not pose a particular problem. Also,
It goes without saying that the application of pressing force is unnecessary.

The process shown in Figure 4e is similar to Figure 2e.
As for the sealing process, like the first sealing process mentioned above,
In this embodiment, the glass bead member 11 of the combination Xb', the support rod 9, and the other end 1b of the glass tube 1 are simultaneously heat-welded in an atmosphere of a desired rare gas, such as xenon gas 13, to form the tube member Ta. This is the process of obtaining. It goes without saying that, like the first sealing step, high-temperature heating is required.

The process shown in FIG. 4f shows the same trigger electrode forming process as the process shown in FIG. A flash discharge tube sealed at both ends will be obtained.

As is clear from the above explanation, Figures 4 a to f
The embodiment shown in FIG. 2 has the same steps as the embodiment shown in FIGS.
1 and 12 are welded to the support rod 9, the electrode rod 10, and the glass tube 1 in the first and second sealing steps, respectively, so that the glass bead members 11 and 12 in FIG.
It can be said that this is an embodiment in which 12 welding operations can be omitted.

In addition, the replacement of each process in FIGS. 4a to 4f is as follows.
Although it is difficult to replace the number 12 due to management reasons,
Regarding f, it goes without saying that the trigger electrode forming step shown in FIG. 3f may be changed to the step shown in FIG. 3, which can be easily changed back and forth as needed, as in the previous embodiment.

Effects of the Invention In the flash discharge tube sealed at both ends according to the present invention, the glass tube 1 and both electrodes are hermetically sealed via the glass bead members 11 and 12, and the metal plate 7 which also serves as an electrode lead is provided at the end of the glass tube. , 8, no pressing force is required for the sealing work, and therefore there is no need to consider the pressing force application configuration or deformation, etc., and it is easy to reduce the cost and reduce the variation in discharge path length, making it more compact. This has the effect of providing a finished discharge tube. In addition, since the difference in thermal expansion coefficient in the sealing part does not need to be taken into account since the work is basically an airtight sealing process between glasses, it is possible to increase the degree of freedom in setting the shape and material of the metal plates 7 and 8. ,
For example, it also has the effect of easily providing a flash discharge tube sealed at both ends with a uniform thickness.

Further, the method for manufacturing a flash discharge tube sealed at both ends according to the present invention includes a step of installing a glass bead member, and the end portion of the glass tube 1 is basically sealed between the glasses, so that a pressing force is applied. This makes it possible to perform the sealing operation easily and in a short time without any problems, and has the effect of reducing manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a flash discharge tube sealed at both ends according to the present invention, and FIGS. 2 a to f are schematic steps showing an embodiment of a method for manufacturing a flash discharge tube sealed at both ends according to the present invention. Fig. 3 is a schematic process diagram showing another example of the trigger electrode forming process explained in Fig. 2f, and Fig. 4
Figures a to f show schematic process diagrams showing other embodiments of the same manufacturing method. FIG. 5 is a sectional view showing an example of a conventionally known flash discharge tube sealed at both ends. DESCRIPTION OF SYMBOLS 1... Glass tube, 4... Cathode, 6... Trigger electrode, 7, 8... Metal plate, 9... Support rod, 10...
... Electrode rod (anode), 11, 12 ... Glass bead member, 13 ... Xenon gas.

Claims (1)

[Scope of Claims] 1. A glass tube that is an envelope in which a rare gas is sealed, a pair of metal plates that also serve as electrode leads, an electrode rod that serves as an anode that is welded to each of the metal plates, and A support rod that supports a cathode, and a support rod that is provided on a portion of each of the electrode rod and support rod and has an outer diameter smaller than the inner diameter of the glass tube, and is heat-welded to both ends of the glass tube to form the electrode rod. and a support rod at both ends of the glass tube, and a glass bead member for positioning metal plates welded to the electrode rod and the support rod at both ends inside the glass tube, and a glass bead member near the tip of the support rod. A flash discharge tube sealed at both ends, comprising a fixed cathode and a trigger electrode made of a transparent conductive film formed in a predetermined area of the outer peripheral surface of the glass tube. 2. The both-ends sealed flash discharge tube according to claim 1, wherein the metal plate is positioned at both ends of the glass tube with a space between the ends and the space. 3. A welding process in which an electrode rod serving as an anode and a support rod supporting a cathode are welded to each of a pair of metal plates that also serve as electrode leads, and a part of the electrode rod and support rod is welded to the inner diameter of a glass tube that will be an envelope. a glass bead member installation step of installing a glass bead member having a smaller outer diameter; a cathode fixing step of fixing a cathode near the tip of the support rod; and a cathode fixing step of installing a glass bead member having a smaller outer diameter; a first sealing step of heating and welding one of the installed glass bead members and sealing one of the electrode rod or the support rod to the one end via the glass bead member; and the other end of the glass tube. A glass bead member installed on the electrode rod or support rod that was not heat welded in the first sealing step is heat welded to the other end in a predetermined rare gas atmosphere, and the other end is sealed with the first seal. a second sealing step of sealing the electrode rod or support rod that was not sealed in the step; and a trigger electrode forming step of forming a transparent conductive coating that will become a trigger electrode in a predetermined range of the outer peripheral surface of the glass tube. A method for manufacturing a flash discharge tube sealed at both ends. 4. The both-ends sealed flash discharge according to claim 3, wherein the glass bead member installation step is a step of fitting and inserting a cylindrical glass bead member into a part of the electrode rod and the support rod, and then heating and welding the glass bead member. Method of manufacturing tubes. 5. The glass bead member installation step is a step of fitting and installing a cylindrical glass bead member into a part of the electrode rod and the support rod, and the first and second sealing steps include:
The double-end sealed flash discharge according to claim 3, wherein the step is to heat-weld the glass bead member and the electrode rod or support rod at the same time as heat-welding the glass bead member and the end portion of the glass tube. Method of manufacturing tubes. 6 The trigger electrode forming step is performed in the first or second
The method for manufacturing a discharge tube sealed at both ends according to claim 3, which is carried out before the sealing step is performed.