JP4973509B2 - Short arc type high pressure discharge lamp - Google Patents

Description

  The present invention relates to a short arc type high pressure discharge lamp. In particular, the present invention relates to a short arc type high-pressure discharge lamp having a foil seal structure that is lit with high power.

  Short arc type high-pressure discharge lamps are used in various exposure processes such as semiconductor wafers and liquid crystal substrates. In recent years, an increase in exposure area and an increase in throughput have been demanded, and on the other hand, characteristics such as a long life have been demanded.

On the other hand, as a sealing structure for a short arc type high-pressure discharge lamp, a rod seal structure and a foil seal structure are conventionally known.
The foil seal structure is such that a metal foil is interposed between an electrode (electrode axis) and an external lead to ensure an electrical conduction structure, and the metal foil portion is hermetically sealed. Furthermore, in a high-power type lamp, a structure is known in which a plurality of metal foils are arranged at intervals on the outer peripheral surface of a glass member using a columnar glass member. Such a structure is disclosed in, for example, Utility Model Registration No. 2583317 and Japanese Patent Application Laid-Open No. 2005-302392.

Thus, the structure in which the sealing portion is formed by the columnar glass member and the plurality of metal foils has an advantage that it is suitable for a large current because the number of metal foils is large.
On the other hand, there is a problem that a so-called crack may be generated between the metal foil and the material (quartz glass) constituting the sealing portion, and the growth of the crack causes a problem that the discharge lamp is damaged. It was generated. This phenomenon tends to occur more easily with a lamp having a higher operating pressure.
Utility model registration No. 2583317 JP 2005-302392 A

  The problem to be solved by the present invention is to provide a short arc type high-pressure discharge lamp having high withstand voltage characteristics while responding to a demand for a large current.

In order to solve the above-mentioned problems, a short arc type high-pressure discharge lamp according to the present invention includes a light emitting part having a pair of electrodes opposed to each other and encapsulating a light emitting material, and a seal formed at both ends of the light emitting part. It has the structure which consists of a stop part.
The sealing portion includes a columnar glass member and a substantially strip-shaped metal foil disposed on the outer surface of the glass member so as to extend along the longitudinal direction of the glass member. Is characterized in that, in the portion corresponding to the peripheral edge of the electrode-side end surface of the glass member, the width in the lateral direction is locally narrowed.

  Further, the glass member has a frustoconical structure in which the electrode side end portion is reduced in diameter, and the metal foil is locally short even in a portion corresponding to a bent portion of the outer surface of the glass member. The width of the direction is narrow.

  Further, the metal foil is characterized in that the width in the lateral direction is locally narrowed even in a portion corresponding to the peripheral edge of the end surface opposite to the electrode side end surface of the glass member.

As a result of intensive studies, the present inventors have found that a crack is formed between the metal foil and the material constituting the sealing portion (quartz glass) in the structure in which the sealing portion is formed by the columnar glass member and the plurality of metal foils. It was ascertained that the cause of this was the wrinkles of the metal foil that occurred when the metal foil was bent.
And this invention can eliminate generation | occurrence | production of a wrinkle by reducing locally the width | variety of the transversal direction of the said metal foil in the part by which the metal foil is bent, or reduces drastically until it does not disappear. It is.

FIG. 1 shows a schematic configuration of a short arc type high-pressure discharge lamp according to the present invention.
A short arc type high-pressure discharge lamp (hereinafter also simply referred to as “discharge lamp” or “lamp”) 10 is entirely made of quartz glass, and a light emitting portion 11 and rod-shaped sealing portions 12 are integrally formed at both ends thereof. Has been. A light emitting space is formed inside the light emitting unit 11, and the anode 2 and the cathode 3 are disposed to face each other with a gap of 5.0 mm, for example. The light emitting portion 11 has a spherical shape or a spindle shape elongated in the tube axis direction.

  The light emitting part is filled with mercury as a luminescent substance and an inert gas such as xenon as a starting gas. As an example, the amount of mercury enclosed is about 1 mg / cc to 100 mg / cc, and the operating pressure reaches 0.1 MPa to 10 MPa pressure. An emission line spectrum with a wavelength of 365 nm or the like is generated by emission of mercury.

The anode 2 is made of tungsten and has a substantially bullet shape having a flat portion at the tip, and is supported by the anode rod 2a.
The cathode 3 is made of thorium tungsten, has a conical tip portion, and is supported by the cathode bar 3a.
For the anode 2 and the cathode 3, a groove formed by, for example, laser irradiation can be formed on the outer peripheral surface of the electrode in order to enhance the heat dissipation effect. Further, a getter material such as tantalum can be attached to the anode rod 2a and the cathode rod 3a.

  The anode rod 2a and the cathode rod 3a both have roots extending toward the sealing portion 12, and each sealing portion 12 is connected to a molybdenum foil (not shown) to form an airtight sealing structure. Yes. An external lead 13 protrudes from the outer end of the sealing portion 12, and a power supply device is connected to the external lead 13 to supply current. The anode 2 and the cathode 3 do not need to be physically separated from the anode rod 2a and the cathode rod 3a, respectively. For example, the anode 2 and the cathode 3 may extend with the same outer diameter and have a physically integrated structure. It doesn't matter.

  FIG. 2 shows an enlarged cross-sectional structure of the anode side sealing portion 12 shown in FIG. The sealing portion 12 includes a columnar glass member 20, a disk-shaped conductive plate 21, a cup-shaped conductive member 22, a holding cylinder 23 through which the electrode shaft 2 a passes, and a metal foil 5. An electrode (electrode shaft) is disposed at one end of the glass member 20 and an external lead 13 is disposed at the other end, and electrical conduction between the two is formed with the metal foil 5 interposed.

  As for the glass member 20, quartz glass becomes the whole rod shape, and the main part 20a has comprised the column shape. The electrode-side end of the glass member 20 has a truncated cone shape (conical truncated portion 20b) whose outer diameter is gradually reduced, and the conductive plate 21 is disposed on the end surface 20c. The size of the end surface 20c at the electrode side end of the glass member 20 is approximately equal to or slightly larger than the size of the conductive plate 21. An external lead insertion hole is formed at the end of the glass member 20 on the external lead 13 side, and the tip of the external lead 13 is held down. A cup-shaped conductive member 22 is disposed on the end surface of the glass member 20 on the external lead 13 side, and is joined to the metal foil 5. A cylindrical external lead holding cylinder 24 is disposed around the external lead 13. It should be noted that the electrode-side end face of the glass member 20 may also have a structure in which an anode shaft insertion hole is provided so that the anode shaft 2a penetrates the disc-shaped conductive member 2 and is held in the glass member 20. Absent.

  The holding cylinder 23 has a cylindrical shape in which a through hole of the anode shaft 2a is formed, and is entirely made of quartz glass. Since a minute gap is formed between the inner surface of the holding cylinder 23 and the outer surface of the electrode shaft 2a, when the lamp is lit, the operating pressure in the light emitting space is passed through the gap to the conductive plate 21. It has reached the vicinity. The outer periphery of the holding cylinder 23 is squeezed with a sealing tube to form a sealing portion.

FIG. 3 shows a cross-sectional structure taken along the line AA of FIG. Five metal foils 5 are arranged with a gap on the outer peripheral surface of the glass member 20. In FIG. 2, among the five metal foils, only the metal foil 5a and the metal foil 5d are shown. Each metal foil 5 has a strip shape (band shape), and is disposed so as to extend along the side surface of the glass member 20 and in the longitudinal direction of the glass member 20. One end of the metal foil 5 is joined to the electrode-side surface of the disk-shaped conductive member 21 by, for example, resistance welding, and the other end is joined to the side surface of the cup-shaped conductive member 22 by resistance welding or the like.
In addition, although metal foil is flat form initially and becomes a curved-surface shape along the shape of a glass member in the production | generation process of a sealing part, it can also be made into a curved-surface shape from the beginning. Generation of wrinkles in the metal foil can be suppressed.

FIG. 4 shows an enlarged structure of the metal foil, and particularly shows a state where it is buried in the sealing portion. (A) shows the cross-sectional structure of the same direction as FIG. 1, (b) shows the state seen from the B direction in (a). (C) shows the same state as (b), but the position where the code | symbol is attached | subjected differs.
The metal foil 5 includes a region 51 corresponding to the columnar portion 20a of the glass member 20, a region 52 corresponding to the truncated cone portion 20b, and a region 53 corresponding to the electrode side tip surface 20c. A boundary 5a between the region 51 corresponding to the cylindrical portion 20a and the region 52 corresponding to the truncated cone portion 20b corresponds to the boundary 20d between the cylindrical portion 20a and the truncated cone portion 20b of the glass member 20, and the truncated cone. The boundary 5b between the region 52 corresponding to the portion 20b and the region 53 corresponding to the electrode tip surface 20c corresponds to the boundary 20e between the truncated cone portion 20b of the glass member 20 and the electrode tip surface 20c.

As can be seen from FIG. 4B, a narrow portion S <b> 1 in which the width of the metal foil in the short direction is locally reduced is formed at the boundary 5 a of the metal foil 5. In addition, a narrow portion S2 in which the width in the short direction of the metal foil is locally small is also formed at the boundary 5b of the metal foil 5.
In this way, wrinkles that occur during bending can be prevented by locally narrowing the width in the lateral direction at the portion where the metal foil is to be folded. And if generation | occurrence | production of a wrinkle is prevented, generation | occurrence | production of the crack in the said part will also be prevented. When wrinkles are generated, a minute gap is generated between the metal foil and the quartz glass. As described above, since the high operating pressure in the light emitting space reaches the conductive member 21, if there is a minute gap, it acts on the gap and leads to the generation and growth of cracks. In this respect, the present invention can prevent the generation of cracks because it can prevent or minimize the generation of wrinkles.

When a numerical example is shown with reference to FIG. 4C, the size 51L in the longitudinal direction of the metal foil 5 is selected from a range of 50 to 90 mm, for example 70 mm, and the size 51W1 in the short direction of the metal foil 5 is 6 Selected from the range of ˜13 mm, for example, 12 mm, and the size 51 W 2 in the short direction of the electrode side tip is selected from the range of 4-7 mm, for example, 5 mm, corresponding to the longitudinal direction of the metal foil of the narrow portion S1 The direction size S1L is selected from the range of 3 to 6 mm, for example, 5 mm, and the size S1W in the direction corresponding to the short direction of the metal foil of the narrow portion S1 is selected from the range of 1 to 3 mm, for example 2.5. The size S2L in the direction corresponding to the inclination direction of the metal foil of the narrow width portion S2 is selected from the range of 1 to 4 mm, for example, 3 mm, the size in the direction corresponding to the short direction of the metal foil of the narrow width portion S2. The length S2W is selected from the range of 0.5 to 2 mm, for example, 1.5 mm.
The size in the length direction of the glass member 20 is selected from the range of 35 to 80 mm, for example, 55 mm, and the size in the radial direction is selected from the range of 19 to 31 mm, for example, 23 mm.

  The width (length in the short direction) of the metal foil 5 gradually decreases at the tip (right side in the figure) from the boundary 5a. This is also for preventing the occurrence of wrinkles and for preventing the metal foils from overlapping each other on the front end surface of the glass member 20.

  In addition, although the truncated cone part 20b of the glass member 20 is an advantageous structure for obtaining a high pressure resistance, it is not essential. When the glass member 20 is a structure that does not have the truncated cone portion 20b, that is, a complete columnar member, the narrow portion S1 of the metal foil is not necessary, and only the narrow portion S2 corresponding to the folding of the end surface is provided.

  FIG. 5 shows another enlarged cross-sectional structure of the anode side sealing portion 12 as in FIG. The sealing portion 12 includes a columnar glass member 20, a disk-shaped conductive plate 21, a disk-shaped conductive member 22, a holding cylinder 23 through which the electrode shaft 2a passes, and a metal foil 4. That is, the structure shown in FIG. 2 is different in that the conductive member 22 on the external lead side has a cup shape, whereas in the present embodiment, it has a disk shape.

FIG. 6 shows a metal foil used in the sealing part structure of FIG. (A) And (b) shows drawing seen from the same direction as FIG.4 (b), respectively, and shows different embodiment, respectively. The metal foil shown in FIG. 6 is different from the metal foil shown in FIG. 4 in that, in addition to the narrow portions S1 and S2, a narrow portion S3 is formed in the bent portion on the external lead side.
The effect of the narrow portion S3 is to prevent wrinkles that occur at the time of bending, so that airtightness on the lead side is maintained and oxidation is prevented.

  The narrow portion S can be made, for example, by cutting off a part from a rectangular metal foil using a press, or can be cut off by irradiating YAG laser radiation light like a single stroke. . In addition, when making the whole metal foil into a curved surface shape according to the shape of a glass member, a curved surface shape can be formed simultaneously with a cutting | disconnection at the time of a press by manufacture with a press. On the other hand, in the manufacture by laser irradiation, a curved surface is separately processed after a flat metal foil is formed.

  In addition, in the said Example, although the structure which arranged five metal foils in the outer periphery of the glass member was illustrated, it is not necessarily limited to such embodiment. That is, the present invention can be applied without being limited to the number of metal foils as long as the metal foil is arranged around the glass member.

  In addition, when the width | variety of metal foil is comparatively large compared with the outer diameter of a glass member, it is easy to generate | occur | produce a wrinkle with respect to bending of metal foil. Therefore, in such a case, the formation of the narrow portion of the present invention is particularly effective. In terms of numerical examples, this is particularly effective when the outer diameter of the glass member is φ23 to φ30 and the width of the metal foil is 10 mm to 12 mm.

  In addition, although the glass member 20 illustrated the column shape, the structure which has a cavity inside may be sufficient.

  FIG. 7 shows another embodiment of the anode 3. The anode 3 has a structure having an electrode body 30 and a heat transfer body M therein. The electrode body 30 is made of a refractory metal or an alloy mainly composed of a refractory metal, and has a container shape in which a sealed space S (hereinafter also referred to as “internal space”) is formed. The heat transfer body M is a metal hermetically sealed inside the electrode body 30 and is made of a metal having a melting point lower than that of the metal constituting the electrode body 30. The electrode body 30 is fixed to the shaft portion 3a with an adhesive.

  As the metal constituting the electrode body 30, a refractory metal having a melting point of 3000 (K) or more, such as tungsten, rhenium, or tantalum, is employed. In particular, tungsten is preferable in that it hardly reacts with the internal heat transfer body M, and so-called pure tungsten having a purity of 99.9% or more is preferable. In addition, as an alloy mainly composed of a refractory metal, for example, a tungsten-rhenium alloy mainly composed of tungsten can be adopted. The resistance to repetitive stress at high temperatures is high, and the life of the electrode can be extended.

  The heat transfer body M is made of a metal having a melting point lower than that of the metal constituting the electrode body 30. Specifically, when tungsten is used as the constituent material of the electrode main body 30, gold, silver, copper, or an alloy containing these as a main component can be used as the heat transfer body M. Of these, silver and copper are preferred materials, and silver is the most suitable metal. This is because silver and copper do not form an alloy with tungsten, and thus are desirable metals in the sense that they function stably as a heat transporter.

As another specific example, when rhenium is used as the metal constituting the electrode body 30, tungsten can be used as the heat transfer body M.
The advantage of employing rhenium as the metal constituting the electrode body 300 is that it can prevent corrosion of the electrode in the case of mercury lamps and metal halide lamps encapsulating halogen, thereby extending the life of the discharge lamp. is there.

  The electrode body 30 has a substantially container-like structure having a sealed space S inside. For this reason, even if the heat transfer body M is heated and melted and a part thereof is vaporized, it does not leak into the light emitting space of the light emitting unit 11. Therefore, the discharge lamp according to the present invention does not need a mechanism for supplying and discharging a cooling medium from the outside like a water-cooled discharge lamp and can hold the cooling mechanism with a very simple structure. For example, the cooling mechanism can be operated continuously without replenishing the heat transfer body until the life of the discharge lamp is reached. In other words, the conventionally proposed high-power discharge lamp relies on a cooling mechanism outside the discharge lamp, whereas the discharge lamp according to the present invention cools the lamp itself with a very simple structure. It has a function. This electrode structure is described in, for example, Japanese Patent Application Laid-Open No. 2004-6246.

1 shows an overall configuration of a short arc type high-pressure discharge lamp according to the present invention. The sealing part of the short arc type high pressure discharge lamp which concerns on this invention is shown. The sealing part of the short arc type high pressure discharge lamp which concerns on this invention is shown. 1 shows a metal foil of a short arc type high-pressure discharge lamp according to the present invention. The sealing part of the short arc type high pressure discharge lamp which concerns on this invention is shown. 1 shows a metal foil of a short arc type high-pressure discharge lamp according to the present invention. 4 shows another embodiment of an anode of a short arc type high-pressure discharge lamp according to the present invention.

Explanation of symbols

2 Cathode 2a Cathode rod 3 Anode 3a Anode rod 5 Metal foil 10 Discharge lamp 11 Light emitting portion 12 Sealing portion 13 External lead 20 Glass member 21 Disk-shaped conductive member 22 Cup-shaped conductive member 23 Holding cylinder S1 Narrow portion S2 Narrow Part S3 Narrow part

Claims (3)

In a short arc type high-pressure discharge lamp comprising a light emitting portion in which a pair of electrodes are arranged opposite to each other and a light emitting material is sealed, and sealing portions formed at both ends of the light emitting portion,
The sealing portion has a columnar glass member and a substantially strip-shaped metal foil disposed on the outer surface of the glass member so as to extend along the longitudinal direction of the glass member,
A short arc type high-pressure discharge lamp characterized in that the metal foil has a locally narrow width in a short side direction at a portion corresponding to a peripheral edge of an electrode side end face of the glass member. The glass member has a frustoconical structure whose diameter is reduced at the electrode side end,
2. The short arc type high-pressure discharge according to claim 1, wherein a width of the metal foil is locally narrow in a portion corresponding to a bent portion of an outer surface of the glass member. lamp.   2. The metal foil is characterized in that a width in a short direction is locally narrowed even in a portion corresponding to a peripheral edge of an end surface opposite to an electrode side end surface of the glass member. 2. A short arc type high pressure discharge lamp according to 2.

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