JP7185521B2 - discharge lamp - Google Patents

Description

The present invention relates to an electrodeless discharge lamp such as an excimer lamp or an external electrode type fluorescent lamp that emits light by dielectric barrier discharge or capacitively coupled high-frequency discharge, and particularly to a small-diameter excimer with improved reliability of the discharge vessel. Regarding lamps.

An excimer lamp with a double-tube structure that has an inner tube coaxial with the central axis of the discharge vessel and irradiates the inside of the inner tube with ultraviolet rays generated in the discharge space, and a pair of electrodes on opposite sides of the discharge vessel. , one of the electrodes is embedded inside the tube wall of the outer tube, and the other electrode is provided on the outer surface of the outer tube (Patent Document 1).

A discharge lamp in which a cladding tube is integrally formed on the outer peripheral surface of a discharge vessel by welding, and at least one of a pair of electrodes is embedded between the outer peripheral surface of the discharge vessel and the inner peripheral surface of the cladding tube. There is an excimer lamp having a structure in which a part of the outer surface of the container is exposed without being covered with the outer covering tube (Patent Document 2).

In such an excimer lamp, when the cladding tube is integrally formed by welding, it is difficult to weld the cladding tube integrally to the ends thereof. Therefore, if the end of the cladding tube is not welded as described in Patent Document 1, a wedge-shaped gap is formed between the end of the cladding tube and the discharge vessel.

There is a possibility that the wedge-shaped gap may cause the lamp to break, and the reliability of the excimer lamp is impaired. In addition, there is a problem that a coating film is not formed in this wedge-shaped gap, and unnecessary ozone is generated by ultraviolet rays emitted from this portion.

In order to eliminate such a wedge-shaped gap, as described in Patent Document 2, the end of the cladding tube is welded so as to be smaller than the maximum diameter of the discharge vessel and integrated with the discharge vessel. However, if the end portion of the cladding tube is reduced in diameter by heating during processing in this way, the discharge vessel will also be deformed by heating. was there. Here, if the discharge vessel is not sufficiently heated and welded for fear of deformation, minute wedge-shaped voids will remain, which will cause lamp damage and insulation breakdown (abnormal discharge) starting near the end of the cladding tube. .

JP 2016-146295 A JP 2018-055965 A

In view of the above problems, the problem to be solved by the present invention is to prevent the deformation of the discharge vessel of an excimer lamp having a double-tube structure in which the outer peripheral surface is covered with a cladding tube, while preventing damage to the lamp and dielectric breakdown. To provide an excimer lamp having a discharge vessel which can be sufficiently heated and welded in order to eliminate minute wedge-shaped voids which are the starting point of the discharge.

A discharge lamp according to the present invention includes a discharge vessel filled with a discharge gas, a cladding tube covering a part of the discharge vessel by welding, and a pair of electrodes facing each other in the radial direction of the discharge vessel. A discharge lamp in which an electrode is embedded between an outer peripheral surface of a discharge vessel and an inner peripheral surface of a cladding tube, wherein a part of the axial range surrounding the discharge space of the discharge vessel includes the discharge vessel and the cladding tube. By having a different diameter portion that is formed thicker in the radial direction than the other portion in the axial range by welding together, while preventing deformation of the discharge vessel, the starting point of lamp damage and dielectric breakdown In order to eliminate the minute wedge-shaped gaps that would otherwise result, it is possible to provide a discharge lamp having a discharge vessel that can be sufficiently heated and welded.

A part of the axial range of the discharge vessel has an exposed portion that is not covered with the cladding tube and is exposed in the radial direction, and the cladding tube, the different-diameter portion, and the exposed portion form a continuous curved surface. As a result, it is possible to provide a discharge lamp having a discharge vessel in which minute wedge-shaped gaps, which are starting points for lamp damage and dielectric breakdown, are eliminated between the cladding tube, the different-diameter portion, and the exposed portion.

The maximum outer diameter of the different-diameter portion is formed larger than the outer diameter of other portions in the axial range of the cladding tube, so that the discharge vessel can be sufficiently heat-welded while preventing deformation of the discharge vessel. It can be a discharge lamp.

The minimum inner diameter of the different-diameter portion is smaller than the outer diameter of the portion in the axial direction surrounding the discharge space of the discharge vessel. It can be a discharge lamp with

The different diameter portion is formed by welding the end of the cladding tube to a portion that is thicker in the radial direction than the rest of the axial range of the discharge vessel, thereby preventing deformation of the discharge vessel. , a discharge lamp having a discharge vessel that can be sufficiently heat welded.

The end portion of the cladding tube is formed so as to become thinner in the radial direction toward the exposed portion, and the inner diameter of the end portion of the cladding tube is formed larger than the inner diameter of the other portion of the axial range of the cladding tube. Thus, it is possible to provide a discharge lamp having a discharge vessel free from minute wedge-shaped voids that may cause lamp damage or dielectric breakdown.

The cladding tube, the different-diameter portion, and the exposed portion are covered with a coating impermeable to light including ultraviolet rays, thereby forming an ultraviolet-impermeable coating on the discharge vessel without wedge-shaped voids. Thus, a discharge lamp that prevents ozone generation can be obtained.

At least part of the axial range of the cladding tube is covered with a conductive coating, so that the discharge lamp can be provided with an ultraviolet-impermeable coating that also serves as an external electrode.

At least a part of the axial extent of the cladding tube is insulated on the side to which the power supply line electrically connected to the electrode embedded between the outer peripheral surface of the discharge vessel and the inner peripheral surface of the cladding tube is connected. insulation breakdown (abnormal discharge) between the power supply line electrically connected to the embedded electrode (inner electrode) and the conductive coating (outer electrode). It can be a prevented discharge lamp.

In an excimer lamp having a double-tube structure, it is possible to provide an excimer lamp with improved reliability by preventing lamp breakage originating near the end of the cladding tube.

1 is a schematic external view of an excimer lamp that is a first embodiment; FIG. 1 is a schematic axial cross-sectional view of an excimer lamp of a first embodiment; FIG. 1 is a schematic radial cross-sectional view of an excimer lamp according to a first embodiment; FIG. FIG. 2 is a schematic axial cross-sectional view of an excimer lamp of a second embodiment; FIG. 2 is a schematic radial cross-sectional view of an excimer lamp according to a second embodiment; FIG. 7 is a schematic axial cross-sectional view of an excimer lamp of a third embodiment;

An excimer lamp of a first embodiment will be described below with reference to FIGS. 1 to 3. FIG. FIG. 1 is a schematic external view of an excimer lamp. FIG. 2 is a schematic axial cross-sectional view of the excimer lamp, and FIG. 3 is a schematic radial cross-sectional view of the excimer lamp.

1 to 3, a discharge vessel 10 of an excimer lamp 1, which is a discharge lamp, forms a discharge space S by fusing and sealing both ends of an outer tube 12 made of a dielectric material such as quartz glass.

In a part of the axial range surrounding the discharge space S of the discharge vessel 10, a welding end portion 12B is provided on the side of the axial end portion (the end portion on the exposed portion 13 side) that is welded to the cladding tube 20 described below. . The welded end portion 12B has a smaller inner diameter than the other portion of the axial range of the discharge vessel, thereby forming a curved surface that is thick in the radial direction of the discharge vessel and continuous with the inner peripheral surface of the discharge vessel. Form.

An introduction pipe 15 that spatially connects the outside of the discharge vessel 10 and the discharge space S is provided, and the inside of the discharge vessel 10 (discharge space S) is evacuated to remove impurities. After that, discharge gas is sealed inside the discharge vessel 10, and the introduction tube 15 is heated and melted to hermetically seal the inside of the discharge vessel 10. As shown in FIG.

The discharge space S is filled with a rare gas such as Xe or a mixed gas of a rare gas and a halogen gas as a discharge gas. The filling pressure of the discharge gas is set to, for example, 5 kPa to 150 kPa. In this embodiment, Xe gas is sealed as the discharge gas.

The cladding tube 20 is formed by coaxially reducing the diameter of a tubular member made of quartz glass with an inner diameter larger than the maximum outer diameter obtained by adding the height of the introduction tube 15 to the outer diameter of the discharge vessel 10 . It is welded integrally with the outer peripheral surface of the outer tube 12 which is a part of. A part of the other axial range of the discharge vessel 10 is not covered with the cladding tube 20 and forms an exposed portion 13 exposed in the radial direction.

Here, the different diameter portion 16 is formed by welding the weld end portion 12B, which is the axial end portion of the discharge vessel to be welded with the cladding tube 20, and the end portion 20B of the cladding tube. Since the welded end 12B of the discharge vessel is a portion with a smaller inner diameter (thicker in the radial direction) than the rest of the axial extent of the discharge vessel 10 (outer tube 12), the end 20B of the cladding tube is It is possible to prevent the discharge vessel 10 (outer tube 12) from being deformed by heating when the diameter is reduced by heating.

Further, the diameter direction thickness of the inner diameter and outer diameter of the different diameter portion 16 varies continuously along the axial direction according to the shapes of the welded end portion 12B of the discharge vessel and the end portion 20B of the cladding tube. It is the part where As a result, the cladding tube 20, the different diameter portion 16, and the exposed portion 13 form a continuous curved surface. By forming such a continuous curved surface, it is possible to prevent the formation of a wedge-shaped gap between the end of the cladding tube and the discharge vessel.

The welded end 12B of the discharge vessel that is welded to the cladding tube 20 is a radially thicker portion than the rest of the axial range of the discharge vessel 10, so that it is integrated with the welded end 12B of the discharge vessel. By welding in such a manner as to prevent the discharge vessel from being deformed by heating, it is possible to prevent the formation of a wedge-shaped gap between the end of the cladding tube and the discharge vessel.

The first electrode 31 and the second electrode 32 are foil electrodes made of molybdenum material. and the inner peripheral surface of the cladding tube 20. A first power supply line 41 and a second power supply line 42 are electrically connected to one ends of the first electrode 31 and the second electrode 32 , respectively, and taken out of the cladding tube 20 . The other end terminates completely embedded inside the tube wall.

The first power supply line 41 and the second power supply line 42 are electrically connected to an AC high voltage power supply (not shown) to supply power to the excimer lamp 1 . Since the first electrode 31 and the second electrode 32 are embedded inside the tube wall, dielectric breakdown between the first electrode 31 and the second electrode 32 outside the discharge vessel 10 is prevented.

Here, by welding the cladding tube end 20B to the welded end 12B, which is radially thicker (smaller in diameter) than the rest of the axial range of the discharge vessel, a minute Since no wedge-shaped void remains, the reliability of preventing dielectric breakdown can be improved.

When a high frequency high voltage is applied between the first electrode 31 and the second electrode 32, the first electrode 31 and the second electrode 32 face each other through the dielectric (the outer tube 12). A discharge is generated in the discharge space S in the directional range (effective light emitting area). Ultraviolet rays generated by the discharge pass through the outer tube 12 and the cladding tube 20 and are emitted to the outside of the excimer lamp 1 .

When the discharge occurs, excimer light with a predetermined spectrum is emitted. For example, the discharge gas is 172 nm for Xe gas, 126 nm for Ar gas, 146 nm for Kr gas, 165 nm for ArBr gas, 193 nm for ArF gas, 222 nm for KrCl gas, 253 nm for XeI gas, 308 nm for XeCl gas, and 283 nm for XeBr gas. , KrBr gas emits ultraviolet rays including a wavelength of 207 nm.

Thus, in a portion of the axial extent surrounding the discharge space of the discharge vessel, the integral welding of the discharge vessel and the cladding tube results in a radially larger diameter than the other portion of the axial extent. In order to prevent deformation of the discharge vessel and to eliminate minute wedge-shaped voids that cause lamp breakage and dielectric breakdown, the discharge vessel can be sufficiently heat-welded. Discharge lamps can be provided.

The excimer lamp of the second embodiment will be described below with reference to FIGS. 4 and 5. FIG. FIG. 4 is a schematic axial cross-sectional view of the excimer lamp, and FIG. 5 is a schematic radial cross-sectional view of the excimer lamp.

4 and 5, a discharge vessel 110 of an excimer lamp 101, which is a discharge lamp, has an outer tube 112 made of a dielectric material such as quartz glass whose diameter is reduced at both ends to form an inner tube 111 made of a dielectric material such as quartz glass. The discharge space S is formed by melting and sealing at the sealing portions 114A and 114B. Inside (hollow portion) of the inner tube 111, an inner fluid (not shown), which is an object to be irradiated, is arranged. An outer tube 112, which is a part of the discharge vessel 110, is provided with a large diameter portion 113A and a small diameter portion 113B.

A part of the axial range surrounding the discharge space S of the discharge vessel 110 (large diameter portion 113A) is a portion to be welded with the cladding tube 120 described below, and the small diameter portion 113B (exposed portion) side thereof is A welded end portion 112B, which is an end portion, is provided. The welded end portion 112B has an outer diameter larger than that of the large diameter portion 113A, so that the welded end portion 112B is radially thicker than the rest of the axial range of the discharge vessel. A continuous curved surface is formed with the portion 113B.

An introduction pipe 115 that spatially connects the outside of the discharge vessel and the discharge space S is provided in the small diameter portion 113B, and the inside of the discharge vessel 110 (discharge space S) is evacuated to remove impurities. After that, discharge gas is sealed inside the discharge vessel 110, and the introduction tube 115 is heated and melted to hermetically seal the inside of the discharge vessel 110. As shown in FIG.

The cladding tube 120 is a tubular member made of quartz glass having an inner diameter larger than the outer diameter of the discharge vessel 110, and is coaxially reduced in diameter by heating so that at least a part of the outer peripheral surface of the large-diameter portion 113A is shrunk. Welded as one piece. The small diameter portion 113B is not covered with the cladding tube 120 and forms an exposed portion 113 exposed in the radial direction.

Here, the different diameter portion 116 is formed by welding the weld end portion 112B, which is the axial end portion of the discharge vessel 110 welded to the cladding tube 120, and the end portion 120B of the cladding tube. The welded end portion 112B of the discharge vessel is a portion having a larger outer diameter (thick in the radial direction) than other portions of the axial range of the discharge vessel 110 (large diameter portion 113A), so that the end portion of the cladding tube Heat deformation of the discharge vessel 110 (the large diameter portion 113A and the small diameter portion 113B) can be prevented when the diameter of the discharge vessel 120B is reduced by heating.

The different diameter portion 116 is a portion whose inner diameter, outer diameter, and radial thickness change continuously along the axial direction according to the shapes of the welded end portion 112B of the discharge vessel and the end portion 120B of the cladding tube. is. As a result, a continuous curved surface is formed by the cladding tube 120, the different diameter portion 116, and the small diameter portion (exposed portion) 113B. By forming such a continuous curved surface, it is possible to prevent the formation of a wedge-shaped gap between the end of the cladding tube and the discharge vessel.

The outer diameter of the different diameter portion 116 is different from the outer diameter of the other portion of the axial range of the cladding tube 120 because the cladding tube end portion 120B is welded to the welded end portion 112B, which is a portion having a large outer diameter. formed relatively large.

The welded end portion 112B of the discharge vessel that is welded to the end portion 120B of the cladding tube is a portion that is radially thicker than other portions of the axial range of the discharge vessel 110 (the large diameter portion 113A and the small diameter portion 113B). Therefore, by welding so as to be integrated with the welded end portion 112B of the discharge vessel, the discharge vessel is prevented from being deformed by heating, and a wedge-shaped gap is formed between the end of the cladding tube and the discharge vessel. can be prevented.

Furthermore, the end portion 120B of the cladding tube welded to the welded end portion 112B of the discharge vessel is formed so as to become thinner in the radial direction toward the small diameter portion 113B (exposed portion). By making the inner diameter larger than the other part of the axial range of the cladding tube, the welding between the end of the cladding tube and the discharge vessel can be strengthened and the formation of wedge-shaped voids can be prevented.

The inner electrode 131 is a foil-shaped electrode made of molybdenum material. The inner electrode 131 is embedded in the tube wall between the outer peripheral surface of the outer tube 112 and the inner peripheral surface of the cladding tube 120 by heat-reducing the diameter of the cladding tube 120 and integrating it with the outer tube 112 . An inner power supply line 141 is electrically connected to one end of the inner electrode 131 and led out of the cladding tube 120 . The other end is completely embedded inside the tube wall of the cladding tube 120 and terminates.

The outer electrode (not shown) is a film electrode made of an aluminum material. No outer electrode is provided in the small diameter portion 113B of the discharge vessel. An outer electrode is provided over the entire circumference of the cladding tube 120 in the large diameter portion 113A of the discharge vessel.

Here, when it is desired to irradiate the inside (hollow portion) of the inner tube 111 with the ultraviolet ray emitted from the discharge generated in the discharge space S and not the outside of the discharge vessel, the outer electrode and the inner tube 111 are used. By providing the welded sealing portion 114B, the small diameter portion 113B of the outer tube, the introduction pipe 115, the different diameter portion 116, and the cladding tube 120 over the entire circumference, generation of unnecessary ozone due to leaked ultraviolet rays can be prevented. .

By providing the outer electrode isolated from the portion where the inner feeder line 141 is taken out, dielectric breakdown between the outer electrode and the inner feeder line 141 (inner electrode 131) is prevented. Here, by further covering the side of the cladding tube 120 where the inner power supply line 141 is taken out to the outside with an insulating cladding (insulating tube 150), the effect of preventing dielectric breakdown can be enhanced.

An outer power supply line 142 is electrically connected to the outer electrode via a cylindrical power supply member 143 wound in the circumferential direction. The power supply member 143 is sandwiched between the insulating tube 150 and the end portion 120B of the cladding tube, which is formed larger than the other portion of the axial range of the cladding tube. can be prevented from falling out against

The inner power supply line 141 and the outer power supply line 142 are electrically connected to an AC high voltage power supply (not shown) to supply power to the excimer lamp 101 . Since the inner electrode 131 is embedded inside the tube wall by the cladding tube 120 , dielectric breakdown between the inner electrode 131 and the outer electrode outside the discharge vessel 110 is prevented.

Here, the welded end portion 112B and the end portion 120B of the cladding tube are formed to be radially thicker (larger in outer diameter) than other portions of the axial range of the discharge vessel (outer tube large diameter portion 113A). By welding the , minute wedge-shaped voids do not remain, so that the reliability of preventing dielectric breakdown can be improved.

When a high frequency high voltage is applied between the inner electrode 131 and the outer electrode, the range in the axial direction of the lamp where the inner electrode 131 and the outer electrode face each other via the dielectric (the outer tube 112 and the cladding tube 120). A discharge is generated in the discharge space S of the (effective light emitting area). The ultraviolet rays generated by the discharge are applied to the inner fluid (first object to be irradiated) arranged inside (hollow portion) of the inner tube 111 .

Here, by providing a slit-shaped opening in a part of the outer electrode of the excimer lamp 101 in the circumferential direction, or by using an outer electrode having a mesh-like opening, the ultraviolet rays generated by the discharge can be The light may pass through 112 , the opening of the outer electrode, and the cladding tube 120 to irradiate the outer fluid (second irradiated body) arranged radially outward of the excimer lamp or the lighting detection device.

The excimer lamp of the third embodiment will be described below with reference to FIG. FIG. 6 is a schematic axial cross-sectional view of the excimer lamp. Note that the description of the configuration common to the second embodiment is omitted.

In FIG. 6, an outer tube 212, which is part of a discharge vessel 210 of an excimer lamp 201, which is a discharge lamp, is provided with a large diameter portion 213A and a small diameter portion 213B. A portion of the axial range surrounding the discharge space S of the discharge vessel 210 (large diameter portion 213A) is a portion to be welded with the cladding tube 220 described below, and is a portion of the small diameter portion 213B (exposed portion) side. A welded end 212B is provided as the end. The welded end portion 212B has an inner diameter smaller than that of the large diameter portion 213A and an outer diameter larger than that of the small diameter portion 213B. A continuous curved surface is formed by the large-diameter portion 213A and the small-diameter portion 213B.

A different diameter portion 216 is formed by welding a weld end portion 212B, which is an axial end portion of the discharge vessel 210 that is welded to the cladding tube 220, and an end portion 220B of the cladding tube. The welded end portion 212B of the discharge vessel has a larger outer diameter than the small diameter portion 213B of the discharge vessel and a smaller inner diameter (thicker in the radial direction) than the large diameter portion 213A. Heat deformation of the discharge vessel 210 (the large diameter portion 213A and the small diameter portion 213B) can be prevented when the diameter of the portion 220B is reduced by heating.

The different diameter portion 216 is a portion whose inner diameter, outer diameter, and radial thickness change continuously along the axial direction according to the shapes of the welded end portion 212B of the discharge vessel and the end portion 220B of the cladding tube. is. As a result, a continuous curved surface is formed by the cladding tube 220, the different diameter portion 216, and the small diameter portion (exposed portion) 213B. By forming such a continuous curved surface, it is possible to prevent the formation of a wedge-shaped gap between the end of the cladding tube and the discharge vessel.

The welded end portion 212B of the discharge vessel that is welded to the end portion 220B of the cladding tube is a portion that is radially thicker than other portions of the axial range of the discharge vessel 210 (the large diameter portion 213A and the small diameter portion 213B). Therefore, by welding so as to be integrated with the welded end portion 212B of the discharge vessel, the discharge vessel is prevented from being deformed by heating, and a wedge-shaped gap is formed between the end of the cladding tube and the discharge vessel. can be prevented.

Although the description of other configurations common to the second embodiment is omitted, a similar excimer lamp can be provided.

1, 101, 201 excimer lamps 10, 110, 210 discharge vessels 111, 211 inner tubes 12, 112, 212 outer tubes 13, 113, 213 exposed portions 113A, 213A large diameter portions 113B, 213B small diameter portions 114A, 114B, 214A, 214B sealing portions 15, 115, 215 introduction pipes 16, 116, 216 different diameter portions 20, 120, 220 covering pipes 31, 131, 231 electrodes (inner electrode, first electrode)
41, 141, 241 feeder (inner feeder, first feeder)
42, 142 feeder (outer feeder, second feeder)
150, 250 insulating tube

Claims (7)

A discharge vessel filled with a discharge gas, a cladding tube covering a part of the discharge vessel by welding, and a pair of electrodes facing each other in a radial direction of the discharge vessel, wherein at least one of the electrodes is the discharge vessel. In a discharge lamp embedded between the outer peripheral surface of and the inner peripheral surface of the cladding tube,
A part of the axial range surrounding the discharge space of the discharge vessel has a different diameter formed to be radially thicker than the other part of the axial range by welding the discharge vessel and the cladding tube. has a part
A part of the axial range of the discharge vessel has an exposed portion that is not covered with the cladding tube and is exposed in the radial direction, and the cladding tube, the different-diameter portion, and the exposed portion form a continuous curved surface,
The end portion of the cladding tube is formed so as to become thinner in the radial direction toward the exposed portion, and the inner diameter of the end portion of the cladding tube is compared with the inner diameter of the other portion of the axial range of the cladding tube. A discharge lamp, characterized in that it is formed in a large size . 2. The discharge lamp according to claim 1 , wherein the maximum outer diameter of said different diameter portion is formed larger than the outer diameter of other portions of said cladding tube in the axial direction. 3. The discharge lamp according to claim 1 , wherein the minimum inner diameter of said different-diameter portion is smaller than the outer diameter of the axial range surrounding the discharge space of said discharge vessel. 2. The different diameter portion is formed by welding the end portion of the cladding tube to a portion that is radially thicker than other portions of the axial range of the discharge vessel. 4. The discharge lamp according to any one of 1 to 3 . 5. The discharge lamp according to claim 1, wherein said cladding tube, said different diameter portion and said exposed portion are covered with a coating impermeable to light including ultraviolet rays. 6. The discharge lamp of claim 5 , wherein at least part of the axial extent of the cladding tube is covered with an electrically conductive coating. At least part of the axial range of the cladding tube is on the side to which a power supply line electrically connected to an electrode embedded between the outer peripheral surface of the discharge vessel and the inner peripheral surface of the cladding tube is connected. 7. A discharge lamp as claimed in claim 6 , characterized in that it is covered with an insulating coating.

Images