JP4178961B2 - Discharge tube manufacturing method and discharge tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a discharge tube in which rod-shaped electrodes are sealed at both ends of a glass bulb made of quartz glass, and more particularly, to a method for manufacturing a discharge tube in which no protrusion is formed on a glass bulb.
[0002]
[Prior art]
A discharge tube having a glass bulb made of hard quartz glass is used for a strobe rod-shaped light source or the like. As shown in FIG. 2, this discharge tube has rod-shaped electrodes 3 and 4 sealed at both ends of a glass bulb 1 made of quartz glass through bead glasses 2 and 2, and the glass bulb 1 is sealed. Discharge gas is enclosed. Quartz glass is a glass mainly made of silicon dioxide, exhibits high transparency in the light wavelength region from ultraviolet to infrared, is resistant to thermal shock, and has excellent heat resistance.
[0003]
The electrodes 3 and 4 include a cathode electrode 3 that emits electrons and an anode electrode 4 that receives electrons. The cathode electrode 3 is composed of a rod-like terminal portion 5 that penetrates the bead glass 2 and an electrode portion 6 that is attached to the inner end portion of the terminal portion 5 and emits electrons. The anode electrode 4 is composed of a rod-shaped terminal portion 7 penetrating the bead glass 2 and a getter 8 attached in the vicinity of the inner end portion of the terminal portion 7.
[0004]
Such electrodes 3 and 4 are made of tungsten which does not melt even when heated when sealing both ends of the glass bulb 1. That is, since quartz glass, which is the material of the glass bulb 1, has a high melting point of about 2,000 ° C., the electrodes 3 and 4 are made of tungsten having a melting point of about 3,400 ° C. However, quartz glass has a coefficient of thermal expansion of about 0.55 × 10 ⁻⁶ / ° C., and tungsten has a coefficient of thermal expansion of about 4.5 × 10 ⁻⁶ / ° C., which is significantly different. If it is going to weld directly, the glass bulb 1 will crack. Therefore, the electrodes 3 and 4 are sealed at both ends of the glass bulb 1 through the bead glass 2.
[0005]
The bead glass 2 has a structure in which a through-hole penetrating the electrodes 3 and 4 is formed at the center, the outer diameter is slightly smaller than the inner diameter of the glass bulb 1, and glass having different thermal expansion coefficients is laminated in multiple layers in the radial direction. It has become. That is, the thermal expansion coefficient of the multi-layer glass is about 4.5 × 10 ⁻⁶ / ° C. on the center side, about 0.55 × 10 ⁻⁶ / ° C. on the outside, and gradually increases from the center side to the outside. The melting point of the outer layer of the bead glass 2 is almost the same as the melting point of quartz glass. When the electrodes 3 and 4 are sealed at both ends of the glass bulb 1, the bead glass 2 is bonded to the electrodes 3 and 4 and the glass. The difference in the thermal expansion coefficient of the bulb 1 is absorbed, and the bead glass 2 and the glass bulb 1 are welded without causing cracks in the two and 1.
[0006]
Here, a method of manufacturing such a discharge tube will be described with reference to FIG. The discharge tube is manufactured from a quartz glass T-shaped tube comprising a straight main tube 9 and a branch tube 10 connected in the middle of the main tube 9.
[0007]
First, as shown in FIG. 3A, multilayer bead glasses 2 and 2 penetrating the electrodes 3 and 4 are inserted into both ends of the linear body tube 9. And as shown in FIG.3 (b), both ends of this main body pipe | tube 9 are heated, both these ends and the bead glass 2 are fuse | melted, and both 9 and 2 are welded. The melting point of the quartz glass and the melting point of the glass of the bead glass 2 are almost the same, so that they can be surely welded, and the thermal expansion coefficient of the bead glass 2 constitutes the electrodes 3 and 4 on the center side. Since it is formed so as to be the same as tungsten, the main tube 9 and the bead glass 2 are not cracked due to the difference in thermal expansion coefficient between quartz glass and tungsten.
[0008]
Thereafter, as shown in FIG. 3C, the branch pipe 10 is used to discharge the air in the main body tube 9, and subsequently, a discharge gas such as xenon gas is sealed in the main body tube 9. Thereafter, as shown in FIG. 3 (d), the connecting portion between the branch pipe 10 and the main body pipe 9 is heated by the burner 11, thereby cutting the branch pipe 10 from the main body pipe 9 and being cut. The discharge tube in which the projection 12 is formed is completed by being blocked by the glass of the branch tube 10 where the small hole is cut.
[0009]
A paste-like sealing material is applied to both ends of the quartz glass tube portion, and each tube portion is placed in a tubular projection protruding from a pair of soft glass sealing portions penetrating the electrodes. Patent Document 1 discloses a discharge tube in which end portions are inserted and both end openings of a tube body portion and a tubular protrusion of a sealing portion are heated and melted to combine them. The coefficient of thermal expansion of soft glass is about 5.6 × 10 ^-6 / ° C, about 10 times that of quartz glass, but the sealing material with a coefficient of thermal expansion approximately halfway between that of soft glass and quartz glass is the both ends of the tube part. And the tubular protrusion of the sealing portion, the two can be combined without cracking.
[0010]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-190275
[Problems to be solved by the invention]
By the way, the discharge tube has a shape in which the projection tube 12 is formed although the T-tube branch tube 10 made of quartz glass is cut and the small hole formed by this cutting is closed by the glass of the branch tube 10. It has become. However, the small hole may not be completely blocked, and in this case, the discharge gas in the glass bulb 1 leaks from the projection 12 and the discharge tube does not emit light from the beginning or gradually stops emitting light.
[0012]
Further, even if the small hole is completely closed, the protrusion 12 is easily subjected to vibration or impact when the discharge tube is transported, causing the glass bulb 1 to be damaged. Further, in the light emission durability test of the discharge tube, the protrusion 12 may be damaged or broken. When the discharge tube is attached at a predetermined position, the direction of the protrusion 12 must be taken into consideration, and not only the working efficiency is poor, but the attached discharge tube is different from the other portions at the protrusion 12. Since light is emitted in a state, so-called uneven light distribution (unevenness) occurs.
[0013]
On the other hand, the discharge tube disclosed in Patent Document 1 absorbs the difference in thermal expansion coefficient between the soft glass constituting the sealing portion and the quartz glass constituting the tubular body portion by the sealing material interposed therebetween. The two are joined without cracks. Therefore, in order to reliably absorb the difference in thermal expansion coefficient between soft glass and quartz glass, the sealing material must be thickened. However, when the sealing material becomes thick, the outer diameter of the sealing portion increases, and it is impossible to meet the demand for downsizing the discharge tube.
[0014]
Accordingly, the present invention provides a method of manufacturing a discharge tube that can seal an electrode without causing cracks in a glass bulb made of quartz glass in which no protrusion is formed, and can further reduce the diameter. An object is to provide a discharge tube using the same.
[0015]
[Means for Solving the Problems]
The discharge tube according to the present invention is a discharge tube in which an end bulb made of hard or soft glass is welded to an end portion of a main bulb made of quartz glass by a relay bulb,
The relay valve is a glass having a lower melting point and a higher thermal expansion coefficient than the main valve on the main valve side, and a higher melting point and a thermal expansion coefficient on the end valve side than the end valve. It is low glass and is characterized in that it has a melting point that gradually decreases from the main valve side toward the end valve side and that its thermal expansion coefficient increases stepwise. Further, in the discharge tube manufacturing method, in order to seal rod-shaped electrodes at both ends of a quartz glass glass bulb, hard or soft glass end bulbs are welded to a quartz glass main bulb. As a relay, the main valve side is a glass having a lower melting point and a higher thermal expansion coefficient than the main valve, and the end valve side is a glass having a higher melting point and a lower thermal expansion coefficient than the end valve. A relay formed by welding a plurality of glasses so that the melting point is gradually reduced and the thermal expansion coefficient is gradually increased from the main valve side toward the end valve side. using the valve, the step of producing a glass bulb, the ends of the main valve not adhering one end the valve or end valve, and a step of sealing the bar-shaped electrode, said electrodes The sealed have not end in the valve, the step of which is made of hard or soft glass made from the end valve and the same quality of the glass, temporarily stopping the bead glass to penetrate the electrode of the bar, the bead glass After discharging the air in the glass bulb from the end bulb side temporarily fixed, and sealing the discharge gas into the glass bulb from the end bulb side, welding the bead glass to the end bulb, And a step of sealing a rod-shaped electrode penetrating the bead glass to the end bulb.
[0016]
According to this method for manufacturing a discharge tube, first, the intermediate bulb has a low thermal expansion coefficient and a high melting point. The end valve made of hard or soft glass is welded coaxially.
[0017]
And, when welding the end bulbs to the both end edges of the main bulb, for example, by melting one end bulb in a bowl shape, or inserting bead glass penetrating the electrode in advance into one end bulb Then, by melting the end bulb and the bead glass, the rod-shaped electrode is sealed to the end bulb on one side.
[0018]
On the other hand, when the end valve is welded only to one end edge of the main valve, for example, the glass having a different thermal expansion coefficient in the radial direction is used at the end of the main valve where the end valve is not welded. Are stacked in multiple layers and welded with a bead glass penetrating the electrode in the center to seal the electrode.
[0019]
And insert the bead glass penetrating the electrode into the end bulb side where the electrode is not sealed, and then leave the bead glass between the inner surface of the end bulb and the outer surface of the bead glass. Temporarily fix. Therefore, after the air in the glass bulb is discharged from the gap and the discharge gas is sealed, the end bulb and the bead glass are melted to weld them together. In this way, since the melting point and the thermal expansion coefficient of the end bulb and the bead glass are the same, the end bulb and the bead glass can seal the electrode without causing cracks.
[0020]
In the method for manufacturing each discharge tube, the electrode part of the cathode electrode from which electrons are emitted is preferably disposed in the main bulb. The quartz glass forming the main bulb is excellent in impact resistance, so that the glass bulb will not be damaged even if electrons emitted from the cathode electrode collide with the main bulb. The discharge tube manufactured by this method can continue to emit light with the initial characteristics.
[0021]
In the discharge tube manufacturing method, the relay bulb is a glass having one end having a lower melting point and a higher thermal expansion coefficient than the main bulb made of quartz glass, and the other end being an end portion made of hard or soft glass. Glass having a higher melting point than that of the bulb and a low coefficient of thermal expansion, the melting point gradually decreases from the main valve side toward the end valve side, and the thermal expansion coefficient increases stepwise. Thus, it is preferable that a splice glass having a melting point and a coefficient of thermal expansion slightly different from each other in this order is formed by welding a plurality of layers.
[0022]
According to this method of manufacturing a discharge tube, the intermediate bulb is used to weld glass having a slightly lower melting point than quartz glass and a slightly higher thermal expansion coefficient to the edge of the main bulb, and the melting point is higher than that of the glass. Slightly lower glass with slightly higher thermal expansion coefficient is welded one after another, and finally glass with slightly higher melting point and slightly lower thermal expansion coefficient than hard or soft glass is welded to hard or soft glass Since it becomes a structure, the glass bulb | bulb which integrated coaxially the main valve | bulb made from quartz glass from which melting | fusing point and a thermal expansion coefficient differ, and the end glass made from hard or soft glass can be manufactured coaxially.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of a method of manufacturing a discharge tube according to the present invention will be described with reference to FIG. The discharge tube manufacturing method according to the first embodiment does not use a conventional T-shaped tube, and, as shown in FIG. The end bulb 15 made of hard glass is manufactured from a glass bulb 16 integrated coaxially.
[0024]
Quartz glass has a melting point of about 2,000 ° C and a thermal expansion coefficient of about 0.55 × 10 ^-6 / ° C, and hard glass has a melting point of about 600 ° C and a thermal expansion coefficient of about 5.6 × 10 ^-6 / ° C. The intermediate valve 14 for absorbing the difference between the melting point and the thermal expansion coefficient is welded between the end edge of the main valve 13 and the end edge of the end valve 15. The splicing valve 14 is composed of a plurality of splicing glasses that are sequentially welded with different melting points and thermal expansion coefficients between the quartz glass and the hard or soft glass.
[0025]
For example, a joint glass having a melting point of 1,800 ° C. and a thermal expansion coefficient of about 1 × 10 ⁻⁶ / ° C. is welded to both ends of the main bulb 13. For example, a joint glass having a melting point of 1,600 ° C. and a thermal expansion coefficient of about 1.5 × 10 ⁻⁶ / ° C. is welded to the other edge of the joint glass. In this way, spliced glasses having different properties are sequentially welded, and finally spliced glass having a melting point of 800 ° C. and a thermal expansion coefficient of about 5 × 10 ⁻⁶ / ° C. is welded. Weld.
[0026]
Thus, the main valve 13 and the end valve 15 having greatly different melting points and thermal expansion coefficients are integrated without any cracks by the intermediate valve 14 in which a plurality of joint glasses are welded. Further, the inner diameter and the outer diameter of the main valve 13, the relay valve 14, and the end valve 15 are the same, and the main valve 13 and the end valve 15 are coaxially integrated by welding them. 16 is manufactured.
[0027]
In order to avoid the need to cut off one end valve 15 in the subsequent step, it is preferable that one end valve 15 is shorter than the other end valve 15.
[0028]
Next, as shown in FIG. 1B, the terminal portion 18 of the cathode electrode 17 is sealed to one end valve 15. For example, when one end valve 15 is heated and melted, the end valve 15 is deformed into a bowl shape, and the terminal portion 18 can be sealed. One end bulb 15 has a length that is necessary and sufficient to seal the terminal portion 18 of the cathode electrode 17, thereby eliminating the need to cut off an excess portion.
[0029]
However, a hard glass bead glass 22 penetrating the terminal portion 18 of the cathode electrode 17 is inserted into the end bulb 15, and the end bulb 15 and the bead glass 22 are heated and melted, whereby the terminal of the cathode electrode 17 is obtained. The part 18 can also be sealed to one end valve 15.
[0030]
However, in any case, the electrode portion 19 of the cathode electrode 17 is preferably disposed in the main bulb 13 so that the inside of the glass bulb 16 is not easily damaged by electrons emitted from the electrode portion 19.
[0031]
Next, a bead glass 22 penetrating the terminal portion 21 of the anode electrode 20 is disposed in the other end bulb 15 as shown in FIG. The bead glass 22 is formed only of hard glass like the end bulb 15 and has an outer diameter slightly smaller than the inner diameter of the end bulb 15.
[0032]
Then, the outer periphery of the end bulb 15 on which the bead glass 22 is arranged is heated by a plurality of burners 24 so that the end bulb 15 of the portion is partially narrowed so that the gap 23 remains, and the bead glass is left. It is assumed that 22 is temporarily fixed at the position. The inner end portion of the terminal portion 21 of the anode electrode 20 penetrating the bead glass 22 is located in the main valve 13, and a getter 25 provided on the inner end side of the terminal portion 21 is located in the relay valve 14. Has been.
[0033]
Next, as shown in FIG. 1C, the air in the glass bulb 16 is discharged from the gap 23, and subsequently, a discharge gas such as xenon gas is sealed into the glass bulb 16 from the gap 23. Thereafter, as shown in FIG. 1 (d), the end bulb 15 around the bead glass 22 is heated again by a burner (not shown), so that the end bulb 15 and the bead glass 22 are melted, and the gap 23 is formed. Block it. Since the end bulb 15 and the bead glass 22 are formed of the same hard glass, the gap 23 is closed without causing cracks in the both, and the terminal portion 21 of the anode electrode 20 is sealed to the end bulb 15 portion. It is done.
[0034]
Finally, when the end bulb 15 protruding from the position where the bead glass 22 is welded is cut out by the cutter 26, a discharge tube as shown in FIG. 1E is completed.
[0035]
Next, a second embodiment of the discharge tube manufacturing method according to the present invention will be described. In the discharge tube manufacturing method of the second embodiment, the relay bulb 14 is welded to one end edge instead of the both end edges of the main bulb 13, and the end bulb 15 is welded only to the one end edge. is there. At the other end of the main valve 13 made of quartz glass, to which the end bulb 15 is not welded, a bead glass 2 (refer to FIG. 3) in which glass having different thermal expansion coefficients in the radial direction is laminated in the same manner as in the past. 17 terminal portions 18 are sealed.
[0036]
However, the subsequent steps such as disposing the bead glass 22 penetrating the terminal portion 21 of the anode electrode 20 in the end bulb 15 welded to one end side of the main bulb 13 are the same as those in the first embodiment. Therefore, the description is omitted.
[0037]
In addition, this invention can be variously changed within the range of the technical matter described in the claim, without being limited to the said embodiment. For example, the end bulb 15 can be made of soft glass instead of hard glass. In addition, the melting point and the thermal expansion coefficient of the relay valve 14 described in the embodiment are merely examples, and needless to say, they can be arbitrarily changed.
[0038]
Further, the relay valve 14 can be manufactured by welding to the end valve 15 and welding it to the main valve 13. Further, the cathode electrode 17 and the anode electrode 20 may be sealed at the opposite end valve 15 or the other end of the main valve 13.
[0039]
【The invention's effect】
According to the present invention, a glass bulb is manufactured by welding a main bulb made of quartz glass and an end bulb made of hard or soft glass with a relay valve so that a gap is formed in the end bulb. Since the bead glass can be temporarily fixed, the air in the main bulb can be discharged, and the discharge gas can be sealed in the main bulb, it is possible to manufacture a discharge tube without using a conventional T-tube. it can.
[0040]
Therefore, the discharge tube manufactured according to the present invention does not form a small hole in the glass bulb, and the discharge gas does not leak from the small hole, so that the discharge gas does not emit light due to the leakage of the discharge gas. Can be eliminated. Further, since the projection is not formed on the glass bulb, it is difficult to receive vibrations or shocks when the discharge tube is transported, and the glass bulb can be prevented from being damaged. In addition, since it is possible to prevent damage and destruction from the protrusions in the light emission durability test of the discharge tube, the yield can be improved. Furthermore, when the discharge tube is attached at a predetermined position, it is not necessary to consider the direction of the protruding portion, and the efficiency of the assembly work can be improved. Since the discharge tube emits light uniformly over the entire length, the quality can be improved.
[0041]
In addition, the main bulb made of quartz glass and the end bulb made of hard or soft glass are welded by a relay bulb whose melting point and coefficient of thermal expansion change gradually, so that the discharge bulb with a thin outer diameter can be obtained. It can be provided and can be mounted on various miniaturized devices.
[Brief description of the drawings]
1 is an embodiment of a manufacturing method of a discharge tube according to the present invention, wherein (a) to (e) are cross-sectional views showing respective steps. FIG. 2 is a cross-sectional view of a conventional discharge tube. (A) to (d) are cross-sectional views showing the respective steps.
13 Main valve 14 Relay valve 15 End valve 16 Glass valve 17 Cathode electrode 19 Electrode part 20 Anode electrode 22 Bead glass

Claims (2)

A discharge tube in which an end bulb made of hard or soft glass is welded to an end of a quartz bulb main bulb by a relay bulb,
The relay valve is a glass having a lower melting point and a higher thermal expansion coefficient than the main valve on the main valve side, and a higher melting point and a thermal expansion coefficient on the end valve side than the end valve. A discharge tube characterized by being made of low glass and having a melting point that decreases stepwise and a coefficient of thermal expansion that increases stepwise from the main bulb side toward the end bulb side . A method for manufacturing a discharge tube in which rod-shaped electrodes are sealed at both ends of a glass bulb made of quartz glass,
The end valve made of glass having a lower melting point and a higher thermal expansion coefficient than the main valve is used as a relay for welding an end valve made of hard or soft glass to a main valve made of quartz glass. The glass has a melting point higher than that of the end valve and a low coefficient of thermal expansion, and the melting point gradually decreases from the main valve side toward the end valve side, and the coefficient of thermal expansion is Manufacturing a glass bulb using a spliced bulb formed to increase in stages;
Sealing a rod-like electrode at one end of the end valve or the end of the main valve where the end valve is not welded;
In the end bulb that does not seal the electrode, a step of temporarily fixing a bead glass made of hard or soft glass and made of the same quality as the end bulb, and penetrating the rod-shaped electrode;
After discharging the air in the glass bulb from the end bulb side temporarily fixing the bead glass, sealing the discharge gas into the glass bulb from the end bulb side;
A method of manufacturing a discharge tube, comprising: welding the bead glass to the end bulb, and sealing the rod-shaped electrode penetrating the bead glass to the end bulb.

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