JP6929763B2 - Discharge lamp and manufacturing method of discharge lamp - Google Patents

Description

The present invention relates to a discharge lamp, and more particularly to a sealing structure of a sealing tube connected to both ends of the arc tube.

In a short arc type discharge lamp or the like, sealing tubes are integrally formed at both ends of the arc tube, and inside the sealing tube, a mount component including an electrode support rod for supporting the electrodes is enclosed. In a discharge lamp having a large rated power, a conductive annular member such as a metal ring is fixed to an electrode support rod, and a plurality of metal foils extending in the axial direction are welded to the annular member. Then, the discharge lamp is turned on by supplying electric power to the electrode via the metal foil, the annular member, and the electrode support rod (see, for example, Patent Document 1).

The coefficient of thermal expansion of an annular member such as a metal ring is different from that of glass. Therefore, when the sealing tube is welded to the glass tube in the sealing step, distortion occurs in the vicinity of the contact surface between the annular member and the glass tube, causing cracks. In order to prevent this, metal disk foils are arranged on both side surfaces of the metal ring to prevent welding of the glass member and the metal ring. Further, when the outer peripheral surface of the metal ring is in contact with the sealing tube, stress is applied to the sealing tube due to the difference in the coefficient of thermal expansion in the radial direction. Therefore, a winding foil is provided to cover the metal ring (see Patent Document 2). The stress caused by the difference in the coefficient of thermal expansion of the metal ring, the wound foil, and the sealing tube is absorbed by the flexible wound foil, and the wound foil is deformed.

Japanese Unexamined Patent Publication No. 2007-115414 JP-A-2010-198947

As the discharge lamp is used, the wound foil changes over time, and the durability of the wound foil decreases. As a result, the wound foil may not be able to absorb the stress.

Therefore, there is a need for an electrode structure that suppresses the occurrence of cracks due to the difference in the coefficient of thermal expansion without covering the annular member such as a metal ring with a metal foil such as a wound foil.

The discharge lamp of the present invention includes an electrode support rod that supports an electrode in the arc tube, a quartz tube through which the electrode support rod is inserted and welded to the sealing tube, and an electrode support rod on the lamp axial end side of the quartz tube. A conductive disk member for electrically connecting the metal foil and a disk foil arranged between the quartz tube and the disk member are provided. Then, a gap (gap) including a space portion formed on the outer side in the radial direction of the lamp from the outer peripheral surface of the disk member is provided. The "disk member" here means a disk-shaped member, and includes an annular member having a hole in the center. Further, the "ramp axial end side" is the end side facing the opposite side to the electrode, and indicates the sealing tube end side.

The outer diameter of the disc foil can be smaller than the outer diameter of the disc member. In this case, the void is a space portion formed between the disk member and the quartz tube, that is, a space portion formed from the electrode side side surface of the disk member not in contact with the disk foil toward the lamp axial electrode side. Can be configured to include.

Further, the gap can be configured to include a space portion formed between the disk foil and the quartz tube, that is, from the electrode side side surface of the disk foil toward the lamp axial direction electrode side.

When the columnar quartz member that abuts on the inner surface side of the metal foil and supports the metal foil is provided, the outer diameter of the disk member can be made smaller than the outer diameter of the disk member side end surface of the columnar quartz member. Further, the metal foil can be connected to the side surface of the disk member on the columnar quartz member side, and the metal foil can be configured to bend outward in the radial direction of the lamp from the outer peripheral surface of the disk member. .. In particular, at least a part of the metal foil can be configured to project toward the quartz tube side from the disk member in the lamp axial direction.

At the end of the quartz tube on the disc member side, a protrusion that protrudes coaxially toward the disc member can be provided, and the outer diameter of the protrusion is smaller than the outer diameter of the disc foil. It may be configured as.

In the method for manufacturing a discharge lamp, which is another aspect of the present invention, a coaxial protrusion is provided at the end of the quartz tube, and a disk foil and a disk member are installed between the quartz tube and the columnar quartz member. , A mount component including an electrode support rod is manufactured, the mount component is inserted into the sealing tube, and the diameter of the sealing tube is reduced by heat treatment.

According to the present invention, it is possible to prevent cracks from occurring in the sealing tube and obtain a discharge lamp having a highly reliable sealing structure.

It is a schematic plan view of the short arc type discharge lamp of this embodiment. It is a schematic cross-sectional view of a sealing tube. It is a figure which showed before sealing and after sealing of an electrode manufacturing process.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic plan view of the short arc type discharge lamp according to the present embodiment.

The short arc type discharge lamp 10 is a lamp in which a pair of electrodes (anode and cathode) are arranged to face each other in a spherical discharge tube 12 made of quartz glass, and a pair of sealed quartz glass is provided at both ends of the discharge tube 12. The stop pipes are connected so as to face each other. However, in FIG. 1, only the electrode 30 which is a cathode and one sealing tube 20 are shown.

A mount component 20A for holding the electrode 30 is enclosed inside the sealing tube 20. The mount component 20A includes an electrode support rod 22 to be joined to the electrode 30, a glass tube (quartz tube) 24 for holding the electrode support rod 22, a columnar glass member (columnar quartz member) 26, and the like, and an end portion of the sealing tube 20. Is closed with a base 28. Mercury and a rare gas are sealed in the discharge space 11. The sealing tube on the anode side is also configured in the same manner.

FIG. 2 is a cross-sectional view schematically showing a part of the sealing tube.

In the sealing tube 20, the electrode support rod 22 is arranged along the electrode shaft (ramp shaft) E. The glass tube (quartz tube) 24, which is a tubular thick glass tube, is welded and integrated with the sealing tube 20, and the electrode support rod 22 is inserted into the shaft hole 24H of the glass tube 24. On the other hand, the columnar glass member 26 has a bottomed tubular recess 26H in the center, the electrode support rod 22 is inserted into the bottomed tubular recess 26H, and the tip surface 22T thereof is in contact with the bottom surface 26T of the recess 26H. .. The electrode support rod 22 is held on the electrode shaft E by the glass tube 24 and the glass member 26.

A conductive metal ring (disk member) 32 is arranged between the glass tube 24 and the glass member 26, and disk-shaped disk foils 34 and 36 sandwich the metal ring 32 on both side surfaces thereof. It is located in. The electrode support rod 22 is inserted through the disk foil 34, the metal ring 32, and the disk foil 36, and the metal ring 32 is welded to the electrode support rod 22.

Metal lead rods (not shown) are coaxially arranged in the sealing tube 20 at predetermined intervals. The lead rod (not shown) is connected to an external lead wire (not shown) connected to the power supply unit (not shown), and like the electrode support rod 22, the metal ring (not shown) and metal. It is inserted through a disk foil (not shown) that sandwiches the ring.

Between the glass member 26 and the sealing tube 20, a plurality of strip-shaped metal foils are arranged at predetermined intervals along the circumferential direction and extend axially along the surface of the glass member 26 (in contact with each other). .. Both ends thereof are welded to a metal ring 32 and a metal ring (not shown) fixed to the lead rod. FIG. 2 illustrates only one metal foil 33 welded to the metal ring 32. The metal foil 33 forms a bent portion 33B while extending along between the tapered portion 26S of the glass member 26 and the sealing tube 20, and the end portion thereof is welded to the metal ring 32.

In the present embodiment, the outer peripheral surface 32F and the side surface 32S2 of the metal ring 32 are not in contact with the glass tube 24, and a gap (void) S is formed. Here, for convenience, the gap portion (space portion) from the outer peripheral surface 32F of the metal ring 32 to the outside in the radial direction is "S1", and the gap portion (side surface 32S2 along the ramp axial direction) from the side surface 32S2 to the axial electrode side. The gap between the glass tube 24 and the end surface 24F of the glass tube 24) is referred to as “S2”. Further, a gap portion formed from the electrode side side surface 34S of the disk foil 34 to the axial electrode side (a gap portion between the side surface 34S of the disk foil 34 along the ramp axial direction and the end surface 24F of the glass tube 24). Is represented by "S3". Due to the formation of the gap S, the end surface 24F of the glass tube 24 is in contact with the bent portion 33B of the disk foil 34 and the metal foil 33, but is not in contact with the metal ring 32.

FIG. 3 is a diagram showing a part of the electrode manufacturing process.

In the state before sealing in the sealing tube 20, the disk foil 36, the metal ring 32, and the disk foil 34 are arranged between the glass member 26 and the glass tube 24. Further, the metal foil 33 is welded to the metal ring 32, and the metal ring 32 is welded to the electrode support rod 22. The metal foil 33 extends along the surface of the glass member 26 and is bent along the end surface 26N of the glass member 26. Since the metal foil 33 is a strip-shaped foil, the metal foil 33 is bent along the tapered portion 26S of the glass member 26 so that the bent portion 33B is generated. At this time, the bent portion 33B is formed so that a part of the bent portion 33B is located on the electrode side of the metal ring 32 along the axial direction.

The glass tube 24 before sealing has a shape in which a protruding portion 24S coaxial with the glass tube 24 including a cylindrical portion through which the electrode support rod is inserted is formed around the central axis to provide a stepped portion. The protruding portion 24S is formed in a cylindrical shape. The outer diameter D1 of the protruding portion 24S is smaller than the outer diameter D4 of the disc foil 34. On the other hand, the outer diameter D2 of the metal ring 32 is set to be smaller than the outer diameter D3 of the end face 26N of the glass member 26. Further, the outer diameter D4 of the disk foil 34 is set to be smaller than the outer diameter D2 of the metal ring 32.

When the mount component 20A including the electrode support rod 22 is inserted into the sealing tube 20 and heat-treated, the sealing tube 20 is welded to the glass tube 24 and the glass member 26. The end face 24F of the glass tube 24 is deformed by heating in the process of heating and welding, and changes into a complicated uneven end face. Then, a gap S is formed. Such a gap S is based on the fact that the outer diameter D2 of the glass tube 24 provided with the protruding portion 24S and the metal ring 32 is smaller than the outer diameter D3 of the end surface 26N of the glass member 26. In particular, the glass is formed by forming a columnar protruding portion 24S, making the outer diameter D1 of the protruding portion 24S smaller than the outer diameter D4 of the disk foil 34, and forming a larger space on the metal ring side than the glass tube end surface 24F. A gap S is formed even if the tube 24 is deformed by heating.

At this time, since a part of the bent portion 33B is formed on the electrode side of the metal ring 32 along the lamp axial direction, the bent portion 33B heats and deforms the glass tube 24, particularly the radial direction of the glass tube 24. It is possible to suppress thermal deformation of the outer portion. As a result, the gap S can be reliably formed even if the glass tube 24 is greatly deformed by heating depending on the heat treatment conditions.

By forming the gap S, the sealed metal ring 32 does not come into contact with the glass tube 24 near the outer peripheral surface 32F, and cracks due to the difference in the coefficient of thermal expansion can be prevented from occurring. Since the gap portion S1 is formed in the radial direction from the outer peripheral surface 32F of the metal ring 32, even if the metal ring 32 expands and contracts in the radial direction during heat treatment and lamp lighting / extinguishing, the end surface of the glass tube 24 The 24F does not come off in a way that it is dragged by it.

Further, in the vicinity of the outer peripheral surface 32F of the metal ring 32, a gap portion S2 is formed in the axial direction between the side surface 32S2 and the glass tube 24. Therefore, even if the metal ring 32 expands and contracts in the axial direction, the end face 24F of the glass tube 24 does not peel off. Further, since the disk foil 34 having an outer diameter smaller than that of the metal ring 32 is also not in contact with the glass tube 24, cracks do not occur due to expansion and contraction of the disk foil 34. In particular, cracks due to thermal expansion and contraction along the axial direction of the disc foils 34 and 36 are formed by forming a gap portion S3 along the axial direction between the side surface 34S of the disc foil 34 and the glass tube 24. It can be prevented from occurring. On the other hand, the columnar protrusion 24S has an outer diameter D1 sufficient to hold the electrode support rod 22.

As described above, according to the present embodiment, the glass tube 24 through which the electrode support rod 22 is inserted is provided in the sealing tube 20 of the discharge lamp 10, and the metal ring 32 and the circle are provided between the glass tube 24 and the glass member 26. The plate foils 34 and 36 are arranged. Then, a gap S is formed in the vicinity of the outer peripheral surface 32F of the metal ring 32 so as not to come into contact with the glass tube 24. The glass member 26 does not have to be provided with a tapered portion.

10 Discharge lamp 20 Sealing tube 22 Electrode support rod 24 Glass tube (quartz tube on the electrode side)
26 Glass member (quartz member)
32 Metal ring (disk member)
33 Metal foil 34 Disk foil 36 Disk foil S Gap

Claims (8)

An electrode support rod that supports the electrodes in the arc tube,
A quartz tube through which the electrode support rod is inserted and welded to the sealing tube,
A conductive disk member that electrically connects the electrode support rod and the metal leaf on the lamp axial end side of the quartz tube, and
A disk foil arranged between the quartz tube and the disk member is provided.
A discharge lamp characterized in that a gap including a space portion formed on the outer side in the radial direction of the lamp from the outer peripheral surface of the disk member is provided. The outer diameter of the disk foil is smaller than the outer diameter of the disk member,
The discharge lamp according to claim 1, wherein the gap includes a space portion formed between the disk member and the quartz tube. The discharge lamp according to claim 1 or 2, wherein the gap includes a space portion formed between the disk foil and the quartz tube. A columnar quartz member that abuts on the inner surface side of the metal foil and supports the metal foil is provided.
The discharge lamp according to any one of claims 1 to 3, wherein the outer diameter of the disk member is smaller than the outer diameter of the end face of the columnar quartz member on the side of the disk member. A columnar quartz member that abuts on the inner surface side of the metal foil and supports the metal foil is provided.
The metal foil is connected to the side surface of the disk member on the columnar quartz member side.
The discharge lamp according to any one of claims 1 to 4, wherein the metal foil is bent outward in the radial direction of the lamp from the outer peripheral surface of the disk member. The discharge lamp according to claim 5, wherein at least a part of the metal foil projects from the disk member toward the quartz tube in the direction of the lamp axis. At the end of the quartz tube on the disk member side, a projecting portion coaxially projecting toward the disk member is provided.
The discharge lamp according to any one of claims 1 to 6, wherein the outer diameter of the protruding portion is smaller than the outer diameter of the disk foil. A coaxial protrusion is provided at the end of the quartz tube.
A disk foil and a disk member are installed between the quartz tube and the columnar quartz member to prepare a mount component including an electrode support rod.
A method for manufacturing a discharge lamp, which comprises inserting the mount component into a sealing tube and reducing the diameter of the sealing tube by heat treatment.

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