Excimer lamp

Abstract

In a double-tube type excimer lamp, an excimer lamp is provided that has a discharge vessel that stably supports the inner tube while increasing ultraviolet irradiation efficiency. In an excimer lamp (10) in which the outer tube (20) and the inner tube (30) are welded to form a discharge vessel (15), the inner tube (30) has a small diameter portion (32) that covers the thin inner electrode (40) and a flange-shaped expanded diameter portion (31) that is welded to the outer tube (20), and has a large diameter portion (34) formed by being integrally connected within the discharge space (S).

Description

Technology Field

[0001] The present invention relates to an excimer lamp, and in particular to the structure of a discharge vessel (discharge tube). Background Technology

[0003] In a double-tube excimer lamp, a light-emitting part is formed by two coaxial cylindrical tubes extending in the axial direction, and a discharge gas is sealed in the discharge space formed between the inner tube and the outer tube. Then, discharge light is emitted by applying a high-frequency voltage between an electrode (inner electrode) installed inside or on the wall of the inner tube, which is a dielectric, and an electrode (outer electrode) on the surface side of the outer tube.

[0004] In the manufacturing process of a double-tube excimer lamp, a flange-shaped portion protruding in the diametrical direction is formed on the inner tube, and by welding the outer tube to the flange-shaped portion of the inner tube, a discharge vessel is formed to form a cylindrical discharge space (see Patent Document 1). Prior art literature

[0006] Japanese Registered Patent Publication No. 5504095 The problem to be solved

[0007] For example, in order to increase the starting performance of a small excimer lamp and simultaneously increase the ultraviolet radiation efficiency, it is necessary to secure an area with as high an electric field strength as possible in the cylindrical discharge space formed along the lamp axis direction, that is, to ensure that the outer diameter and thickness of the inner tube do not increase.

[0008] However, in the structure of a discharge vessel composed of welded portions of an inner tube and an outer tube, a large load is applied near the flange portion corresponding to the support part of the inner tube, which may cause lamp damage.

[0009] Therefore, in a double-tube excimer lamp, a discharge vessel structure that stably supports the inner tube while increasing the starting performance and ultraviolet radiation efficiency is required. means of solving the problem

[0011] The excimer lamp of the present invention comprises an inner tube along the lamp axis direction and an outer tube that is welded to the inner tube to form a discharge space. The inner tube and the outer tube may be composed of weldable materials, such as quartz glass, for example. The inner tube may be configured to cover a thin electrode as an electrode, and may also be configured to be sealed with the thin electrode.

[0012] In the present invention, a large diameter portion is provided in which a flange-like portion is installed for welding the inner tube to the outer tube, and a small diameter portion is provided which has a smaller outer diameter than the large diameter portion and is formed on the discharge space side than the large diameter portion. This provides a structure that improves lighting starting performance and ultraviolet radiation efficiency, and also stably supports the inner tube. The small diameter portion and the large diameter portion may be configured to be integrally connected, for example, within the discharge space.

[0013] For example, the small diameter portion can be configured to be sealed with the foil electrode. Here, "sealing" means that the inner tube is closely attached to the entire foil electrode so that no gap is created between the foil electrode and the small diameter portion. It is possible to configure it to be sealed along the tube axis (ramp axis) along the entire foil electrode. It is possible to configure the small diameter portion to be longer than the foil electrode along the tube axis.

[0014] Additionally, the large diameter portion can be configured to be connected to a feed rod that is connected to a thin electrode. Here, the small diameter portion can be configured to be connected to the connection part between the thin electrode and the feed rod.

[0015] It is possible to configure the thickness of the small diameter portion (thick portion) to be smaller than the thickness of the large diameter portion. In addition, the large diameter portion can be configured to be located on the discharge space side rather than the flange portion, and to have an exposed portion that is exposed to the discharge space.

[0016] Various cross-sectional shapes can be applied to the small diameter portion; for example, the portion covering the thin electrode can be elongated oval or elongated oval. Additionally, the cross-section of the small diameter portion can be circular at the connection portion with the large diameter portion.

[0017] An exhaust pipe with an inner diameter smaller than the maximum diameter of the inner pipe can be formed coaxially at one axial end of the outer pipe. In this case, it is possible to configure the inner pipe to partially contact the inner surface of the exhaust pipe so that one end of the inner pipe does not block the internal space of the exhaust pipe. Effects of the invention

[0019] According to the present invention, in a double-tube type excimer lamp, an excimer lamp is provided having a discharge vessel that stably supports the inner tube while increasing lighting starting performance or ultraviolet radiation efficiency. Brief explanation of the drawing

[0021] FIG. 1 is a schematic cross-sectional view of an excimer lamp according to the present embodiment. FIG. 2 is a schematic cross-sectional view of an excimer lamp along a direction orthogonal to the cross-sectional direction of FIG. 1. FIG. 3 is a schematic cross-sectional view of an excimer lamp according to III-III of FIG. 1. Specific details for implementing the invention

[0022] Hereinafter, an excimer lamp of the present embodiment will be described with reference to the drawings.

[0023] FIG. 1 is a schematic cross-sectional view of an excimer lamp according to the present embodiment. FIG. 2 is a schematic cross-sectional view of an excimer lamp according to a direction orthogonal to the cross-sectional direction of FIG. 1. It is a schematic cross-sectional view of an excimer lamp according to III-III of FIG. 1.

[0024] The excimer lamp (10) is configured as a double-tube excimer lamp and is equipped with a tubular discharge vessel (discharge tube) (15) formed by welding an outer tube (20) and an inner tube (30) made of dielectric material such as quartz glass. The outer tube (20) constituting the discharge vessel (15) has a cross-section formed in a hollow circular shape along the direction of the tube diameter (lamp diameter). In the cylindrical discharge space (S) inside the outer tube (20), a noble gas such as xenon gas, or a mixture of these gases, is sealed as a discharge gas.

[0025] The electrode (hereinafter referred to as the inner electrode) (40) coated on the inner tube (30) is configured as a foil-shaped electrode extending along the tube axis (hereinafter referred to as the lamp axis) (C). The inner electrode (40) is not exposed to the discharge space (S), and a power supply rod (power supply line) (70) is connected to one end (40T) along the direction of the lamp axis (C). The power supply rod (70) is connected to a power supply unit (not shown) installed externally. The inner tube (30) is welded to the outer tube (20) at a flange-shaped portion (hereinafter referred to as the enlarged portion) (31) protruding in the diameter direction to form a discharge vessel (15).

[0026] At the end of the outer tube (20) opposite to the end that is welded to the expanded portion (31), a protruding portion (hereinafter referred to as an exhaust pipe) (22) is formed. The exhaust pipe (22) is a portion formed during the lamp manufacturing process, where the tip of the glass tube, which is the material of the outer tube, is heated and deformed to reduce its diameter, and the exhaust pipe (22) is integrally formed by welding a tip tube that is smaller than the glass tube.

[0027] The inner electrode (40) and the outer electrode (50) are defined here as having positive and negative polarities, respectively. Then, a high frequency (e.g., in the range of several kHz to tens of MHz) and a high voltage (e.g., in the range of several kV to tens of kV) are supplied to the excimer lamp (10) through the feed rod (70). As a result, a dielectric barrier discharge occurs in the discharge space (S), and excimer light of a predetermined spectrum (e.g., wavelength 172 nm) is emitted from the discharge space (S).

[0028] The excimer lamp (10) of the present embodiment is configured as a small excimer lamp. For example, the axial length (luminous length) of the discharge vessel can be set to a range of 20 mm to 400 mm. Also, the outer diameter of the outer tube (20) can be set to a range of 5 mm to 30 mm, preferably a range of 8 mm to 25 mm.

[0029] The thick portion of the outer tube (20) can be set to a range of, for example, 0.8 mm to 1.5 mm, in consideration of preventing deterioration of the discharge tube due to excimer light and suppressing the rise in the discharge initiation voltage. In addition, the inner diameter of the outer tube (20) is set to a range of, for example, 4 mm to 28 mm, preferably 23 mm, in consideration of suppressing discharge instability due to a long discharge distance and insufficient lightness due to a short discharge distance.

[0030] The discharge distance, that is, the distance between the outer surface of the inner tube (30) and the inner diameter of the outer tube (20), can be set to a range of 2mm to 12mm, taking into account the prevention of insufficient light intensity due to the narrowing of the discharge space and the prevention of instability of the discharge due to the expansion of the discharge distance.

[0031] The inner electrode (40) of the tube is arranged coaxially with its center position in the width direction and thickness direction aligned with the center position of the inner tube (30). Additionally, the inner tube (30) is arranged coaxially with respect to the outer tube (20). Thus, the inner electrode (40) is arranged in a position coaxial with respect to the outer tube (20) and in a position symmetrical with respect to the tube axis (C). Here, the width direction of the inner electrode (40) is defined as the Y direction, and the direction perpendicular thereto (thickness direction) is defined as the X direction (see FIG. 3).

[0032] As shown in FIG. 3, the inner electrode (40) has a flat portion (42) of approximately constant thickness and is shaped like a wedge that tapers in a wedge shape from both ends of the flat portion (42) in the width direction to both ends (E1, E2) of the inner electrode (40) in the width direction. However, it may also have a knife edge shape with a cross-section that slopes smoothly from the center toward both ends (E1, E2) of the inner electrode in the width direction along the electrode width direction.

[0033] The inner tube (30) of the present embodiment has a cross-sectional shape with a different diameter along the direction of the tube axis (lamp axis) (C). Specifically, the inner tube (30) is composed of a portion (hereinafter referred to as the small diameter portion) (32) that covers the inner electrode (40) within the discharge space (S) and a portion (hereinafter referred to as the large diameter portion) (34) that covers the power supply rod (70) inside and outside the discharge space (S).

[0034] In the large diameter section (34), an expanded section (31) is installed that is welded to the outer tube (20) in a range (L2) formed along the tube axis (lamp axis) (C), including a portion covering the feed rod (70). In addition, in the large diameter section (34), a portion (hereinafter referred to as the exposed portion) (36) that extends further into the discharge space (S) than the expanded section (31) and is exposed to the discharge space, and a portion (hereinafter referred to as the extended portion) (37) that extends beyond the outer tube (20) and extends from the discharge vessel (15) to the outside of the discharge space (S).

[0035] The diameter portion (32) is formed along the tube axis (lamp axis) (C) in a range (L1) that includes the portion covering the inner electrode (40), and the shape of the diameter cross-section is approximately constant, and the portion near the connection between the inner electrode (40) and the feed rod (70) is also covered and extends to the vicinity of the end (40T) of the inner electrode (40). And, as shown in FIG. 3, the diameter cross-section shape of the portion covering the inner electrode (40) of the diameter portion (32) along the tube axis (C) is not circular, but is elongated oval or elongated oval.

[0036] Specifically, the inner tube (30) is flat in the electrode thickness direction (X direction) and has an outer surface extending along the electrode width direction (Y direction) near the center, and the outline of the cross-section in the diameter direction is semi-elliptical or semi-circular from the outer side near both ends (E1, E2) in the width direction of the inner electrode (40). Hereinafter, the diameter (outer diameter) of the inner tube (30) along the electrode width direction (Y direction) is indicated by the symbol “W11,” and the thickness of the thick part, that is, the distance between the inner electrode (40) and the outer surface, is indicated by the symbol “T11.” Likewise, the diameter (outer diameter) along the electrode thickness direction (X direction) is indicated by the symbol “W21,” and the thickness is indicated by the symbol “T21.”

[0037] In this way, by making the small diameter portion (32) of the inner tube (30) covering the inner electrode (40) into an elongated oval or elongated oval cross section with different diameters (outer diameters) in the electrode width direction (Y direction) and the electrode thickness direction (X direction), the deviation of the discharge in the discharge space in the lamp circumference direction can be suppressed.

[0038] The large diameter portion (34) is circular in cross-section, and the diameter (outer diameter) (W12, W22) along the electrode width direction (Y direction) and the electrode thickness direction (X direction), respectively, is the same, and the thickness (thick portion), i.e., the distance (T12, T22) from the feed line (70) to the surface of the large diameter portion (32), along the electrode width direction (Y direction) and the electrode thickness direction (X direction), respectively, is the same (see FIG. 1 and 2). The diameter (W12) (=W22) of the large diameter portion (34) is larger than the diameter (W11) of the small diameter portion (32) along the electrode width direction (Y direction) (see FIG. 1), and is also larger than the diameter (W21) of the small diameter portion (32) along the electrode thickness direction (X direction) (see FIG. 2).

[0039] The exposed portion (36) of the large diameter portion (34) is continuously connected to the small diameter portion (32), and its outer surface is exposed to the discharge space (S) in the section along the pipe axis (C) direction up to the expanded portion (31) on the flange. In addition, the exposed portion (36) has a tapered shape in which the diameter decreases toward the center of the lamp. Near the connection portion (35) between the small diameter portion (32) and the large diameter portion (34) (see FIG. 1), the cross-section along the electrode width direction (Y direction) becomes a continuous curved shape, resulting in a smooth and stepped shape. The diameter (W12) (= W22) and thickness (T12) (= T22) of the large diameter portion (34) are approximately constant in the extended portion (37).

[0040] The size of the inner diameter of the exhaust pipe (22) is determined such that the inner tube (30) is partially inserted into and maintained within the exhaust pipe (22). Specifically, the inner diameter of the exhaust pipe (22) is smaller than the outer diameter (W11) in the electrode width direction of the inner tube (30) and larger than the outer diameter (W21) in the electrode thickness direction (X direction). As a result, the tip portion (30T) of the inner tube (30) contacts the inner surface of the exhaust pipe (22) in the portion along the electrode width direction (Y direction) and is maintained coaxially by the outer tube (20), thereby making it possible to secure a sufficient surface distance and prevent surface discharge near the tip portion (30T) starting from the tip portion in the tube axis (C) direction of the inner electrode (40).

[0041] In accordance with the present embodiment, in an excimer lamp (10) in which an outer tube (20) and an inner tube (30) are welded together to form a discharge vessel (15), the inner tube (30) has a small diameter portion (32) that covers a thin inner electrode (40) and a large diameter portion (34) that forms a flange-shaped expanded diameter portion (31) that becomes the welded portion of the outer tube (20), and is formed by being integrally connected within the discharge space (S).

[0042] By forming the small diameter portion (32) along the range (L1) along the tube axis (C), including the section covering the inner electrode (40), it becomes possible to set the discharge distance (D1) along the electrode width direction (Y direction) (Fig. 1) and the discharge distance (D2) along the electrode thickness direction (X direction) (Fig. 2) to be relatively long relative to the outer diameter of the lamp. Additionally, it becomes possible to set the thickness (distance) (T11, T21) from the inner electrode (40) along the electrode width direction (Y direction) and electrode thickness direction (X direction) of the small diameter portion (32) to be relatively short relative to the discharge distances (D1, D2) corresponding to these.

[0043] As a result, even in a small excimer lamp (10), it is possible to secure sufficient space for the cylindrical discharge space (S), thereby increasing the lighting startability and simultaneously increasing the ultraviolet radiation efficiency.

[0044] Meanwhile, since the large diameter portion (34) supports the inner tube (30) and the feed rod (70) and is structured to continuously connect the expanded diameter portion (31) that welds to the outer tube (20) to the small diameter portion (32) through the exposed portion (36), it is possible to form a discharge vessel (15) with a double tube structure having a stable support structure even when configuring a relatively long and small excimer lamp (10), and lamp breakage can be suppressed.

[0045] As described above, the small diameter portion (32) of the inner tube (30) is shaped like an elongated ellipse with a small diameter (outer diameter) and thickness, so it is subjected to relatively large stress in the bending direction relative to the large diameter portion (34) in the electrode thickness direction (X direction). However, near the connection portion (the portion covering one end (40T) of the inner electrode (40)) (35) between the large diameter portion (34) and the small diameter portion (32) (see FIG. 1), it is formed in a circular shape. Therefore, the small diameter portion (32) of the inner tube (30) can be stably supported.

[0046] As described above, near the connection portion (35) between the small diameter portion (32) and the large diameter portion (34), the cross-section has a continuous curved shape, and a smooth tapered step is installed. Additionally, a tapered exposed portion (36) that widens toward the expanded diameter portion (31) is formed up to the flange-shaped expanded diameter portion (31). By doing so, a sufficient surface distance can be secured, thereby preventing surface discharge starting from one end (40T) in the direction of the tube axis (C) of the inner electrode (40).

[0047] In particular, since the relatively thin diameter portion (32) is configured to cover the connection portion with the inner electrode (40) and the power supply rod (70), it is possible to increase ultraviolet radiation efficiency throughout the entire discharge space (S) and simultaneously increase lighting startability while reliably suppressing surface discharge.

[0048] Such an excimer lamp (10) can be manufactured, for example, by the manufacturing method described below.

[0049] First, a large diameter portion of the inner tube is formed, and a cylindrical glass tube (hereinafter referred to as the "sealing tube") that is integrally sealed with the outer tube is formed, has an enlarged portion formed therein. At this time, a hollow portion of the inner diameter is provided in the large diameter portion to allow the insertion of a feed rod. Additionally, a cylindrical glass tube (hereinafter referred to as the "sealing tube") that is integrally sealed with a thin electrode and forms a small diameter portion of the inner tube is welded coaxially with the sealing tube. At this time, a hollow portion of the inner diameter is provided in the small diameter portion to allow the insertion of the thin electrode, and the sealing tube is made larger in inner diameter and has a smaller outer diameter and thickness than the sealing tube. Furthermore, this process may be performed instead of the process of machining the glass tube.

[0050] After integrally connecting a feed rod (feed line) to a thin electrode by means of resistance welding or the like, it is inserted into an inner tube in which a large diameter section and a small diameter section are integrally formed. The inside of the inner tube containing the thin electrode and the feed rod is sealed by vacuum suction, and the inner tube is heated from the outside to seal the small diameter section of the inner tube to the thin electrode while simultaneously sealing the large diameter section to the feed line. At this time, heating adjustment is performed so that the cross-sectional shape of the small diameter section becomes an elongated ellipse.

[0051] For example, by rotating the glass tube and heating it with a burner or the like to uniformly shrink (dim) it in the circumferential direction until the inner surface of the glass tube contacts both ends (wedge-shaped portions) of the thin electrode, and by performing a process of shrinking the glass tube between the parts in contact with the ends (wedge-shaped portions) of the thin electrode along the thickness direction of the thin electrode to integrate it with the flat portion, it is possible to weld the glass tube to the thin electrode with an elongated oval or elongated spherical cross section. Additionally, this process may be performed instead of the glass tube coating process.

[0052] Then, an outer tube made of quartz glass or the like is formed with an exhaust pipe at one end and an insertion port at the other end, and an inner tube with a thin electrode and a feed rod attached is inserted into the outer tube, so that the insertion port of the outer tube is welded to the enlarged portion of the large diameter section of the inner tube. The outer tube has an inner diameter corresponding to the outer diameter of the enlarged portion of the inner tube.

[0053] Impurities are removed by heating the entire discharge vessel while performing vacuum suction through the exhaust pipe. Then, after sealing the discharge gas, the exhaust pipe is sealed, and an outer electrode is placed on the outer surface of the outer tube.

[0054] Regarding the small diameter portion (32) of the inner tube (30), it is not necessary to have a cross-sectional shape that is elongated, and a cross-sectional shape that is circular is acceptable. Also, the inner tube (30) may not have a uniform cross-sectional shape throughout along the tube axis (lamp axis) (C), but may have an external shape with different scales or different cross-sectional shapes. For example, it may have an external shape in which the outer diameter (W11) or thickness (T11) along the electrode width direction (Y direction) towards the tip portion (30T) of the inner tube (30) decreases in stages or continuously. Regarding the area near the connection portion (35) between the small diameter portion (32) and the large diameter portion (34), it may also have an external shape in which the diameter increases in stages or continuously from the small diameter portion (32) toward the large diameter portion (34).

[0055] Additionally, it is possible to configure the inner tube (30) so that the tip portion (30T) of the inner tube (30) does not come into contact with the inner surface of the exhaust pipe (protruding portion) (22) of the outer tube (20), and the length (L1) in the direction of the tube axis (C) of the inner tube (30) (small diameter portion (32)) may be set so that it does not reach the exhaust pipe (22). Even in such a configuration, the large diameter portion (34) of the inner tube (30) can stably support the small diameter portion (32).

[0056] The inner electrode (40) can be configured as an electrode other than a thin electrode, for example, it may be configured as a single-sided circular electrode. In addition, the inner electrode may be configured to extend to the outside of the discharge vessel without being connected to the power supply rod. Explanation of the symbols

[0058] 10 Excimer Lamp 15 Discharge Vessel 20 outer tube 30 inner tube 31 Enlarged section (flange-shaped part) 32 Blind Head (Confrontation) 34 Daegyeongbu (Bongjigwan) 40 inner electrode 50 outer electrodes 70 feeder pole (feeder line)

Claims

Claim 1 The apparatus comprises an inner tube along the lamp axis direction, an outer tube welded to the inner tube to form a discharge space, and a thin electrode coated on the inner tube; the inner tube has a large diameter portion on which a flange-like portion welded to the outer tube is installed, and a small diameter portion having an outer diameter smaller than that of the large diameter portion and formed on the discharge space side relative to the large diameter portion; the small diameter portion is sealed with the thin electrode, and the large diameter portion is sealed with a feed rod connected to the thin electrode; the inner tube is flat in the thickness direction of the thin electrode and, near the center, has an outer surface extending along the width direction of the thin electrode; from near both ends in the width direction of the thin electrode outward, the contour of the cross-section in the diameter direction is semi-elliptical or semi-circular; an exhaust pipe with an inner diameter smaller than the maximum diameter of the inner tube is formed coaxially at one axial end of the outer tube, and the tip of one end of the inner tube does not block the internal space of the exhaust pipe. An excimer lamp characterized by partially contacting the inner surface of the exhaust pipe so as not to. Claim 2 An excimer lamp according to claim 1, characterized in that the thickness of the small diameter portion is smaller than the thickness of the large diameter portion. Claim 3 An excimer lamp according to claim 1, characterized in that the large diameter portion is located on the discharge space side rather than the flange-shaped portion and has an exposed portion exposed to the discharge space. Claim 4 An excimer lamp according to claim 1, characterized in that the small diameter portion is connected to the connection portion of the thin electrode and the feed rod. Claim 5 An excimer lamp characterized in that, in any one of claims 1 to 3, the cross-section of the small diameter portion is circular at the connection portion with the large diameter portion. Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete

Images