JP2000277054A - Discharge lamp - Google Patents

Abstract

(57) [Summary] [Problem] Even when operated at high pressure for a long time,
Provided is a discharge lamp in which a crack is not generated at a welded portion between a holding member for supporting an electrode and a sealing tube, and the burst does not occur due to the crack. SOLUTION: This discharge lamp has a structure in which an electrode support rod having an electrode at the tip thereof is held by a holding member having an insertion hole for the electrode support rod at the center thereof in a sealed tube connected to an arc tube. The holding member is a tubular member made of quartz glass, and the outer diameter of the arc tube-side end area, which is one end side of the tubular member, is larger than the outer diameter of the other end side end area. A Mo-made foil member is arranged on the outer periphery of the side end area. Alternatively, the holding member is a Mo-made ring-shaped member, and a Mo-made foil member is arranged on the outer periphery of the Mo-made ring-shaped member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the field of photochemical industry,
The present invention relates to a structure in a sealed tube of a short arc type discharge lamp used in a semiconductor device manufacturing field or the like.

[0002]

2. Description of the Related Art As shown in FIG. 1, in a short arc type discharge lamp, an anode 2 and a cathode 3 are opposed to each other in an arc tube 1 made of quartz glass. Power is supplied from the base 6 through the external lead wire portion 8 and the electrode support rod 4. The hermetic sealing expands a plurality of cut-off seal glasses having an expansion coefficient intermediate between the expansion coefficient of tungsten (W) as the electrode support rod 4 and the expansion coefficient of quartz glass (SiO ₂ ) as the material of the sealing tube 10. The step joint portions 5 are formed by joining in order of the rate. The heavy electrode attached to the tip of the electrode support rod 4 is supported by a thick hollow quartz glass tubular member 20 as a holding member, and is heated and melted from the outside of the tubular member 20 of the sealing tube 10 to be sure. It becomes the structure held in.

In the arc tube 1, an appropriate amount of mercury and / or
Alternatively, a gas is sealed, an electric current is supplied from the metal base 6, and an arc discharge is generated between the anode 2 and the cathode 3. The electrode support bar 4 protruding from the outer portion 11 of the sealing tube is joined to the external lead portion 8 at its outer end by butt welding or the like, and the external lead portion 8 is joined to the metal base 6 by a brazing portion 9. Symbol 7 is an adhesive.

In the case of the conventional discharge lamp shown in FIG. 1, the electrode support rod 4 is welded by welding the outer peripheral surface of a thick hollow quartz glass tubular member 20 as a holding member and the inner peripheral surface of the sealing tube 10. Although it is supported by the tubular member 20, in this case, after being heated and melted at a portion indicated by a symbol 20 </ b> A and a portion indicated by a symbol 20 </ b> B in FIG. When operating at a high pressure, there is a risk that a crack may occur at the position of the symbol 20A or 20B, or that the crack may cause a burst. That is, there were some problems in the quality and reliability of the product.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrode supporting rod which can be operated even at a high pressure for a long time. It is an object of the present invention to provide a safe and reliable discharge lamp in which a crack does not occur in a welded portion between a holding member for holding and a sealing tube, and a burst does not occur due to the crack. .

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 is to provide an electrode supporting rod having an electrode at a tip thereof in a sealing tube connected to an arc tube. A discharge lamp having a structure held by a holding member having an insertion hole for the electrode support rod, wherein the holding member is a tubular member made of quartz glass, and an arc tube side end which is one end side of the tubular member. The discharge lamp is characterized in that the outer diameter of the region is larger than the outer diameter of the end region on the other end side, and a Mo-made foil member is arranged on the outer periphery of the end region on one end side.

According to a second aspect of the present invention, one end of the tubular member, which is the arc tube side, is expanded in a trumpet shape, and the outer diameter of the end of the tubular member expanded in a trumpet shape is reduced. A discharge lamp characterized in that the diameter is substantially equal to the diameter of the anode.

According to a third aspect of the present invention, an electrode support rod having an electrode at its tip and a through hole for the electrode support rod at the center thereof are held in a sealed tube connected to the arc tube. A discharge lamp having a structure held by members, wherein the holding member is a Mo-made ring-shaped member, and a Mo-made foil member is arranged on an outer periphery of the Mo-made ring-shaped member. I do.

[0009]

The holding member is a tubular member made of quartz glass,
By making the outer diameter of the arc tube side end area which is one end side of the tubular member larger than the outer diameter of the other end side end area, by disposing a Mo foil member on the outer periphery of the one end side end area. When the arc tube side end of the sealing tube shrinks in the heating step, the presence of the Mo foil member prevents the arc tube side end of the sealing tube and the holding member from directly contacting each other. Since the member and the sealing tube are not welded, no thermal distortion remains.

In particular, the holding member is a tubular member made of quartz glass, and its end region on the arc tube side is expanded in a trumpet shape, and the outer diameter of the end portion of the tubular member expanded in the trumpet shape is reduced. When the diameter is substantially equal to the diameter of the anode, the amount of diameter reduction in the sealing tube at the heating step of the arc tube side end can be reduced.

Further, even if the holding member is a Mo-made ring-shaped member and a Mo-made foil member is arranged on the outer periphery of the Mo-made ring-shaped member, the holding member is formed in the same manner as when the holding member is a quartz glass tubular member. When the arc tube side end of the sealed tube is shrunk in the heating step, the Mo foil member is present between the Mo ring-shaped member and the sealed tube to hold the sealed tube with the arc tube side end. The members are not welded and no thermal distortion remains.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, as an embodiment of the present invention,
The structure of the discharge lamp according to the present invention will be described. FIG.
FIG. 1 shows a sectional view of a short arc type discharge lamp as an embodiment. An anode 2 and a cathode 3 are placed in an arc tube 1 made of quartz glass.
Are arranged to face each other, and the anode 2 and the cathode 3 are supplied with power from outside the lamp. Each of the electrode support rods 4 and 4 having the anode 2 and the cathode 3 attached to the tip is supported by the tubular members 30 and 30 which are holding members and which have the arc tube side end region expanded in a trumpet shape. I have.

An outer peripheral portion 31 of the tubular member 30 at an end portion on an arc tube side is covered with a Mo foil member 40. FIG. 4A shows the Mo foil member 40 placed in the sealing tube 10.
FIG. 3 is an enlarged cross-sectional view of the tubular member 30 coated with. In addition,
Although the Mo foil member 40 has a small thickness, it is shown thicker for convenience. FIG. 5 is a perspective view of the tubular member 30, and FIG. 6 is a perspective view of the Mo foil member 40.

As shown in FIG. 6, the Mo-made foil member 40 has a hole 41 in the center through which the electrode support rod 4 is inserted. The thickness of the foil is, for example, 10 to 15 μm.
Is covered on the outer peripheral portion 31 in the end region on the arc tube side. And
The Mo foil member 40 is bent so as to wrap around the end region of the tubular member 30 on the arc tube side, and is held by the tubular member 30. FIG. 4 (b) shows a state in which the inner diameter 12 of the sealed tube is reduced in diameter by heating to fix the tubular member 30. FIG. 4 (a)
In this state, the inside of the sealed tube 10 is depressurized, and the inner diameter 12 of the sealed tube is reduced by heating. That is, the inner part 12 of the sealing pipe
The diameter of the heating member is reduced until the inner surface of the member comes into contact with the tubular member 30 and the Mo foil member 40 sandwiched therebetween. Then, the electrode support rod 4 is held while being inserted through the tubular member 30.

Here, the Mo foil member 40 is connected to the tubular member 30.
Is folded so as to enclose the arc tube side end region in order to hold the Mo foil member 40 when the inside diameter of the sealed tube 12 is reduced by heating, and in the present invention, the tubular member 30 is used.
It suffices that the Mo foil member 40 covers the outer peripheral portion 31 of the light emitting tube side end.

As another embodiment of the discharge lamp according to the present invention, a discharge lamp adopting a seal structure using a functionally graded material instead of a seal structure using stepped glass for hermetic sealing is shown. 3 will be described. The sealing tube 10 is closed with a closing body 50 made of a functionally graded material. The closing body 50 made of a functionally graded material has a substantially columnar shape and is made of, for example, silica and molybdenum.
2 is a sintered body in which the ratio of both silica and molybdenum is gradually or stepwise changed so that one end portion 51 has a composition rich in silica to be insulative, and the other end portion 52 has electrical conductivity rich in molybdenum. The electrode support rod 4 penetrates the closing body 50 and is sintered integrally with the closing body 50.

In this example, in order to further ensure the hermeticity of the lamp, the closing body 50 is provided with a brazing portion 53 on the end face of the other end portion 51. Then, the sealing tube outer portion 11 is put on one end portion 51 having a large silica component and having an expansion coefficient close to the expansion coefficient of quartz glass, and is heated and sealed by welding. Then, as in the example of FIG. 1 in which a sealing structure using stepped glass is employed for hermetic sealing, the sealing tube 10 is brought into the state of FIG.
The inside is decompressed, and the inside diameter 12 of the sealed tube is reduced in diameter by heating. In other words, the inner surface of the inner portion 12 of the sealing tube is heated and reduced in diameter until the Mo foil member 40 is in contact with the tubular member 30 with the Mo foil member 40 interposed therebetween. Then, the electrode support rod 4 is held while being inserted through the tubular member 30.

[Withstand pressure test] Next, the results of a withstand pressure test performed to confirm the characteristics of the discharge lamp of the present invention will be described. The withstand pressure test performed in the present application is a test for confirming whether or not burst occurs when nitrogen gas is pressurized and sealed from a tip tube portion of a discharge lamp arc tube and maintained at a constant pressure for 1 hour. It is. The test results are shown in the table of FIG.

A conventional step-sealing method, which is a discharge lamp (No. 1) as shown in FIG. 1 in which a tubular member made of thick glass having a uniform thickness is welded to a sealing tube, and a conventional step-sealing method A discharge lamp (No. 2) as shown in FIG. 2 in which a Mo-made foil member is put on a tubular member whose end region on the arc tube side is expanded in a trumpet shape and fixed to a sealing tube; 3 is a discharge lamp using a closed body made of aluminum, which is fixed to a sealing tube by covering a tubular member having an arc tube side end region expanded in a trumpet shape with a Mo-made foil member and fixing the sealed tube. .
20 pieces of 3) were prepared. All lamp specifications such as power consumption are the same, 4000W, current 100A, voltage 40
V.

No. One lamp was held at a pressure of 50 kg / cm 2 for 1 hour, and as a result, one burst was confirmed. N
o. 2 and No. In the lamp of No. 3, no burst occurred even when the lamp was maintained at a pressure of 50 kg / cm ² for 1 hour, and 65 kg / cm ² was obtained.
It only burst one by one for the first time in cm ² .

[Continuous operation test] Next, the result of the continuous operation test will be described. The continuous operation test performed in the present application is a test in which the discharge lamp is continuously lit for 2,000 hours, and the presence or absence of a crack in the sealing tube or a burst due to the crack is checked. The test results are shown in the table of FIG.

The same specifications as in the pressure resistance test described above were used for No.
1, No. 2 and No. For each of the three lamps, twenty lamps were prepared, and the lamps were continuously lit for 2000 hours. As a result, no. Only one lamp had two cracks.

As is apparent from the above experimental results, N
o. 2 or No. As shown in FIG. 3, the tubular member expanded in a trumpet shape is covered with a Mo-made foil member so as to be fixed to the sealing tube. The foil member did not weld the outer surface of the tubular member and the inner surface of the sealing tube, so that no distortion occurred, and the electrode support rod with the heavy electrode attached was securely held.

In the present invention, a ring member made of Mo may be used instead of the holding member made of quartz glass.
In this case, as shown in FIG. 7, the electrode support bar 4 has a Mo-shaped or Ta (tantalum) fastener 70 as a holding member and a Mo-shaped member 60 having substantially the same diameter as the anode 2. Further, the Mo foil member 40 is attached so as to cover the outer periphery of the Mo ring member 60. Specifically, the Mo-shaped ring member 60 has an outer diameter substantially equal to the anode diameter and a thickness of 0.5 to 4.0 mm. Mo
An outer peripheral portion of the ring-shaped member 60 is covered with a Mo foil member 40. FIG. 8 (a) shows the M
o shows an enlarged sectional view of the ring-shaped member 60 covering the foil-making member 40.

The Mo-made foil member has a thickness of 10 to 15 μm, is coated on the outer peripheral portion 61 of the ring-shaped member 60, and is bent so as to wrap the outer peripheral portion 61 of the ring-shaped member 60. Is held. Then, it is inserted into the sealing tube 10 in this state, the inside of the sealing tube 10 is reduced in pressure, and the end of the sealing tube 10 on the arc tube side is heated and reduced in diameter, as shown in FIG. Hold rod 4.

[0026]

According to the present invention, the electrode support rod on which the heavy electrode is mounted is securely held by the holding member, and the electrode support rod is held for holding the electrode support rod even when operated at a high pressure for a long time. It is possible to provide a safe and reliable discharge lamp in which a crack does not occur at a joint portion between the member and the sealing tube, and an enclosure in the lamp does not leak.

[Brief description of the drawings]

FIG. 1 shows a sectional view of a conventional discharge lamp.

FIG. 2 shows a sectional view of the discharge lamp of the present invention.

FIG. 3 shows an example of a discharge lamp according to the present invention in which a closure made of a functionally gradient material is used.

FIG. 4 shows Mo in a sealed tube of the discharge lamp of the present invention.
FIG. 2 is an enlarged cross-sectional view illustrating a state of a tubular member covering a foil-making member.

FIG. 5 is a perspective view schematically showing a tubular member.

FIG. 6 is a perspective view schematically showing an Mo foil member.

FIG. 7 shows a sectional view of a discharge lamp according to another embodiment of the present invention.

FIG. 8 shows Mo in a sealed tube of the discharge lamp of the present invention.
FIG. 2 is an enlarged cross-sectional view illustrating a state of a Mo-made ring-shaped member covering a foil-making member.

FIG. 9 shows the results of a pressure resistance test.

FIG. 10 shows results of a continuous operation test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 2 Anode 3 Cathode 4 Electrode support rod 5 Joint part 6 Metal base 7 Adhesive 8 External lead part 9 Brazing part 10 Sealing tube 11 Sealing tube outer part 12 Sealing tube inner part 20 Tubular member 30 Expanded tubular member 31 Outer peripheral part 40 Mo foil member 41 Hole 50 Closure body 51 One end 52 Other end 53 Wax sealing part 60 Mo ring-shaped member 61 Outer peripheral part 70 Fastener

Claims (3)

[Claims] 1. A discharge lamp having a structure in which an electrode support rod having an electrode at an end thereof is held by a holding member having a through hole for the electrode support rod at the center thereof in a sealed tube connected to the arc tube. In the above, the holding member is a quartz glass tubular member, and the outer diameter of the arc tube side end region which is one end side of the tubular member is made larger than the outer diameter of the other end side end region. Mo on the outer periphery of the side end area
A discharge lamp, wherein a foil-making member is arranged. 2. An end portion of the tubular member is expanded in a trumpet shape, and an outer diameter of an end portion of the tubular member expanded in a trumpet shape is substantially equal to a diameter of an anode. 2. The discharge lamp according to 1. 3. A discharge lamp having a structure in which an electrode support rod having an electrode at its tip is held by a holding member having an insertion hole for the electrode support rod at the center thereof in a sealing tube connected to the arc tube. 3. The discharge lamp according to claim 1, wherein the holding member is a Mo-made ring-shaped member, and a Mo-made foil member is arranged on an outer periphery of the Mo-made ring-shaped member.