KR20060047354A - Eximer lamp - Google Patents

Abstract

An excimer lamp having an internal electrode provided in a discharge vessel provided with an outer electrode on an outer surface thereof, comprising: an internal electrode exposed from at least one opening of an inner tube provided to cover the inner electrode in the discharge vessel; It is an object to provide an excimer lamp which prevents unwanted creepage discharge between an outer electrode.

A surface discharge prevention means for preventing surface discharge between the inner electrode and the outer electrode protruding from the inner tube is provided at an end portion of the inner tube provided to cover the inner electrode in the discharge vessel. It is done.

Description

Excimer lamp {EXIMER LAMP}

1 shows Embodiment 1 of the present invention.

FIG. 2 is a partially enlarged view of FIG. 1.

3 shows Example 2. FIG.

4 shows Example 3. FIG.

5 shows Example 4. FIG.

6 shows Example 5.

7 shows a conventional example.

Explanation of symbols on the main parts of the drawings

1: excimer lamp 2: discharge vessel

21: light emitting portion 22: sealing portion

3: inner electrode 4: outer electrode

5: inner tube 51: enlarged diameter part

6: internal lead 7: metal foil

8: external lead 10: partition plate

11, 12: additional dielectric (end thickness)

13: conductive member

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excimer lamp that emits excimer light through a dielectric material, and more particularly, to an excimer lamp having an internal electrode in a discharge space.

As a technique related to the present invention, there is, for example, Japanese Patent Laid-Open No. 2-7353, in which an excimer is discharged in a discharge container by filling a discharge gas for forming excimer molecules in the discharge container and discharging it through a dielectric. Excimer lamps are disclosed that produce molecules and extract ultraviolet light emitted from these excimer molecules.

The excimer lamp is also known to have characteristics such as strong emission of ultraviolet light of a single wavelength, which is not found in conventional low pressure mercury discharge lamps and high pressure discharge lamps. As a light emitting device using an excimer lamp, in addition to the above publication, it is disclosed in, for example, Japanese Patent No. 2854255, Japanese Patent Laid-Open No. 2002-168999, and the like.

The excimer lamps (dielectric barrier discharge lamps) disclosed in Japanese Patent Nos. 2854255 and JP 2002-168999 have a double cylindrical shape in which a cylindrical outer tube is disposed coaxially on the outer side of the cylindrical inner tube. The outer electrode is arranged on the outer surface of the outer tube, the inner electrode is disposed inside the inner tube, and the space formed between the outer tube and the inner tube is used as the discharge space.

Fig. 7 shows a schematic configuration of the conventional excimer lamp. (a) shows the whole cross sectional view, (b) shows the A-A cross section of (a).

The excimer lamp 60 is cylindrical in overall shape and is made of synthetic quartz glass. In the discharge lamp 60, the outer tube 61 and the inner tube 62 are arranged coaxially to form a double cylindrical tube, and both ends are closed between the outer tube 61 and the inner tube 62. In the discharge space S is formed. In the discharge space S, an excimer molecule is formed by dielectric barrier discharge, and a discharge gas, for example, xenon gas, which emits vacuum ultraviolet light from the excimer molecule is sealed.

The outer surface of the outer tube 61 is provided with a mesh-shaped outer electrode 63 which is one electrode, and an inner electrode 64 which is the other electrode is provided inside the inner tube 62.

An approximately alternating current power source is connected between the outer electrode 63 and the inner electrode 64, whereby excimer molecules are formed in the discharge space to emit ultraviolet light. The discharge gas is selected according to the light emission wavelength, but, for example, when xenon gas is used, light having a wavelength of 172 nm is emitted.

However, in the excimer lamp of the above structure, (1) two quartz glass tubes, the inner tube and the outer tube, are made into a double cylinder, so that the entire discharge vessel is large, and since the inner tube is welded and supported at the end, it is affected by gravity. It is easy to break, and (2) a manufacturing process for joining two quartz glass tubes at both ends is required, and the manufacturing process is complicated and complicated, and (3) the inner tube is hotter than the coolable outer tube. In other words, there is a problem that a large load is caused by thermal expansion, and in particular, stress is easily concentrated at the junction with the outer tube, and the longer the lamp is, the more serious the effect is.

In addition, as disclosed in Japanese Patent No. 3506055, which is not a double cylinder, there is also an excimer lamp having a structure in which an internal electrode extends in the discharge space. In this structure, since the discharge container consists of one cylindrical body and there is no equivalent to the inner tube in the double cylinder, some of the above problems can be solved.

However, in the excimer lamp of the above structure, since the internal electrode is exposed in the discharge space and the electrode directly acts on the discharge space, (1) the spatial distribution of discharge generated from the electrode tends to be nonuniform, and (2) to the electrode If you do not pay attention to the rapid electrode properties, arc-shaped discharges are generated, so that excimer light is not generated efficiently. (3) When arc-shaped discharges are formed, the parts are glowing and the electrode burns off. (4) Another problem is that the internal electrode metal sputters and contaminates the light extraction portion of the discharge vessel.

(Patent Document 1) Japanese Patent Laid-Open No. 2-7353

(Patent Document 2) Japanese Patent No. 2854255

(Patent Document 3) Japanese Patent Application Laid-Open No. 2002-168999

(Patent Document 4) Japanese Patent No. 3506055

The problem to be solved by the present invention is to eliminate the complexity of the structure of the double cylindrical excimer lamp, the end of the internal electrode in the discharge space to eliminate the disharmony or the like of the discharge of the excimer lamp of the structure in which the internal electrode is directly exposed in the discharge space It is to provide an excimer lamp having a novel structure covered by an open dielectric.

The present invention is an excimer lamp comprising a discharge vessel in which a gas for discharge is enclosed, an inner electrode extending in a longitudinal direction inside the discharge vessel and sealed at an end of the discharge vessel, and an outer electrode disposed on an outer surface of the discharge vessel. The inner surface of the inner electrode is covered by an inner tube made of a dielectric material whose at least one end is discharged between at least one of the outer electrodes, and at least one end thereof is opened in the discharge space. It extends past the end of the outer electrode in the longitudinal direction, characterized in that it has a surface discharge prevention means for preventing unwanted creeping discharge between the inner electrode and the outer electrode protruding from the inner tube.

The creepage discharge preventing means may be creepage distance extending means.

In addition, the surface discharge preventing means is characterized in that the charge reduction means for reducing the charge accumulated on the outer surface near the end of the inner tube.

(The best mode for carrying out the invention)

Hereinafter, the Example of the excimer lamp of this invention is described using FIGS.

Example 1

Figure 1 (a) is a side cross-sectional view obtained by cutting the excimer lamp of the present invention in the longitudinal direction. Fig. 1 (b) is a cross sectional view of Fig. 1 (a), and Fig. 2 is an enlarged view of the main part A thereof.

The excimer lamp 1 has a discharge container 2 made of a dielectric material, for example, synthetic quartz glass, and the discharge container 2 has a tubular light emitting part 21 and a light emitting part at both ends thereof. An encapsulation portion 22 for hermetically sealing 21 is provided. In the light emitting portion 21, a light emitting space S is formed, and a discharge gas is filled.

A coil-shaped inner electrode 3 is disposed inside the discharge vessel 2 along the tube axis X of the discharge vessel 2, and an outer electrode 4 is provided on an outer surface of the discharge vessel 2. The inner lead 6 at both ends of the inner electrode 3 is connected to one end of the metal foil 7 embedded in the pinch sealed encapsulation 22, and at the other end of the metal foil 7, the encapsulation 22 The external lead 8 is connected so as to extend outward.

On the outer circumference of the internal electrode 3, an inner tube 5 made of a dielectric material is provided to cover it. Both ends of the inner tube 5 are open in the discharge space S, and are covered with at least a portion that discharges between the outer electrode 4 of the inner electrode 3 and in the axial direction. It extends past the outer electrode 4.

The inner tube 5 may be supported by the light emitting portion 21 by a support (not shown), or may be supported by the internal electrode 3 by a support not shown.

In the discharge space S formed inside the light emitting portion 21, for example, xenon gas is sealed as a discharge gas for forming excimer molecules by discharge via a dielectric material.

In addition, although the internal electrode 3 showed the coil shape, it is not limited to this, A rod shape and rod shape may be sufficient. However, when the coil-shaped electrode is employed as the internal electrode 3, it has a buffer function against expansion in the axial direction, absorbs the thermal expansion difference with the discharge vessel 2 made of quartz glass, and the sealing portion 22 There is an advantage that the occurrence of cracks can be prevented.

Moreover, also regarding the outer electrode 4, although the illustration is illustrated in semi-cylindrical shape, it is not limited to this, Of course, it may be a cylindrical translucent electrode, for example, a mesh electrode, etc. It may be sufficient.

In addition, the structure of the sealing part 22 is not limited to a pinch seal, It may be another foil seal, ie, a shrink seal structure, and what is called a stage connection seal | sticker can be employ | adopted. However, the advantage of the connection seal is that the adhesion between the glass and the electrode is improved, and gas leakage and crack generation at the sealing portion can be prevented more reliably.

As shown in detail in FIG. 2, an enlarged diameter portion 51 is formed in the vicinity of the end of the inner tube 5, the diameter of which is gradually enlarged on the wrapper. The enlarged diameter part 51 functions as a surface discharge prevention means, and is intended to enlarge the creepage distance from the end of the outer electrode 4 to the inner electrode 3. Therefore, the enlarged diameter portion 51 extends past the outer electrode 4 and is provided on the sealing portion 22 side. However, the position and size of the enlarged diameter portion 51 are the outer electrode 4 and the inner tube of the inner electrode 3. It is selected so that unwanted creepage discharges do not occur between the portions 31 not covered by (5).

In the illustrated example, the creepage distance L is a position B corresponding to E of the inner side pipe 5 at a position A corresponding to the end E of the outer electrode 4 on the inner circumferential surface of the light emitting portion 21. ), A distance L2 along the outer surface of the enlarged diameter portion 51 from B to an end C of the enlarged diameter portion 51, and an internal electrode at C. It becomes total (L = L1 + L2 + L3) of distance L3 until reaching position D of the shortest distance to 3). Therefore, compared with the structure which is the same in total length and does not have a diameter part, the creepage distance can be extended because the distance L3 from C to D is added.

The enlarged diameter portion 51 is not limited to the wrapper shape shown, and may be a tapered shape or a stepped enlarged diameter portion. In other words, the enlarged diameter portion 51 may have a different structure as long as the distance is added to the straight diameter shape.

An approximately high frequency power source is connected to the inner electrode 3 and the outer electrode 4, and dielectric barrier discharge is generated between the two electrodes via a discharge vessel 2 and an inner tube 5, which are dielectric materials, and excimer emission. This occurs.

In the excimer lamp of the present invention, it is not preferable that the inner tube 5 extends to the sealing portion 22 and is embedded in the sealing portion 22. This is because when the inner tube 5 is embedded in the encapsulation portion 22, the same problem as in the excimer lamp of the double cylindrical structure described in the background art occurs.

As mentioned above, according to the excimer lamp of the structure shown to FIG. 1, 2, it is the biggest feature that the enlarged diameter part is formed in the edge part of an inner side pipe | tube, and the advantage is demonstrated below.

The excimer lamp of the present invention has a structure in which the inner tube is not embedded in the sealing portion for the same reason as described above, and the vicinity of the end of the inner electrode is not covered by the inner tube and is directly exposed to the gas for discharge. Therefore, if the distance (called the creepage distance) is not sufficiently secured between the end of the outer electrode and the portion not covered by the inner tube of the inner electrode, undesired creepage discharges are generated between the two ends. The problem arises that the stability of the discharge between the electrodes is lost. Such creeping discharge can be considered to arise in detail corresponding to the edge part of the outer electrode of an inner side pipe | tube toward the inner electrode which protruded from an inner side pipe | tube in detail.

In order to sufficiently prevent the creepage distance in order to prevent this, simply to increase the length of the inner tube relative to the outer electrode, the total length of the discharge vessel as compared to the length of the effective discharge forming portion between the inner electrode and the outer electrode covered with the inner tube In other words, since the ratio of the discharge forming portion to the total length of the lamp becomes small, it is not preferable.

On the other hand, according to the structure of the excimer lamp of the present invention in which the enlarged diameter portion 51 is formed at the end of the inner tube 5, the creepage distance is elongated due to the presence of the enlarged diameter portion 51, so that the discharge forming portion is removed. Since sufficient creepage distance can be ensured without needing to make it excessively short, it becomes possible to reliably prevent generation of unwanted creepage discharges.

The numerical example of the excimer lamp 1 shown in FIG. 1 is shown below.

The discharge vessel 2 has a total length (including the sealing portion 22) of 220 mm to 2820 mm, for example, 1620 mm, and a total length of the light emitting part 21 of 100 mm to 2700 mm, for example, 1500 mm, and an outer diameter of 10 mm to 50 mm. For example, it is 16 mm and inner diameter is 8 mm-48 mm, for example, 14 mm.

The internal electrode 3 has a total length of 190 mm to 2790 mm, for example, 1590 mm, an outer diameter of 1 mm to 40 mm, for example 3 mm, and a pitch of 0.5 mm to 10 mm, for example, 2 mm.

The inner tube 5 has a total length of 170 mm to 2770 mm, for example, 1570 mm, an outer diameter of 2 mm to 42 mm, for example 4 mm, and an inner diameter of 1 mm to 40 mm, for example, 3 mm. The maximum outer diameter of the enlarged diameter part 51 is 4 mm-46 mm, for example, 12 mm. The total length of the other outer electrodes 4 is 100 mm to 2700 mm, for example, 1500 mm.

Creepage distance L is 3 mm-150 mm, for example, 80 mm.

Example 2

FIG. 3 shows another creepage distance extending means. In the drawing, a partition plate 10 made of a non-conductive material is provided in the vicinity of an end portion of the inner tube 5 located outside the outer electrode 4 end. will be. The partition plate 10 may be formed by welding another member made of non-conductive material such as quartz glass or ceramic to the inner tube 5 or by expanding the inner tube 5 itself.

According to the excimer lamp 1 shown in FIG. 3, the distance corresponding to the height H of each partition member 10 is added to the creepage distance L corresponding to the number of partition members 10. Therefore, since the creepage distance L is elongated without reducing the proportion of the discharge formation portion to the entire length of the lamp, the creepage discharge from the outer electrode 4 to the inner electrode 3 not covered by the inner tube 5 is reduced. Occurrence can be prevented favorably.

The second embodiment shown in FIG. 3 shows a numerical example of a portion different from the first embodiment of FIGS. 1 and 2. The partition member 10 has an outer diameter of 7 mm to 47 mm, for example, 13 mm. The inner diameter is 2 mm to 42 mm, for example 4 mm. The thickness (tube axis X direction) is 1 mm to 10 mm, for example, 3 mm. Creepage distance L is 3 mm-150 mm, for example, 80 mm, when two partition members 10 are provided.

Example 3

4 to 6 show a case where charge reduction means for reducing the amount of charges generated on the outer surface of the end of the inner tube 5 is employed as the surface discharge preventing means.

In the third embodiment in FIG. 4, the dielectric 11 is additionally mounted on the outer surface of the end portion of the inner tube 5 by welding or the like. It is preferable that the additional dielectric 11 be made of the same material as the inner tube 5, and when the inner tube 5 is quartz glass, the additional dielectric 11 is also quartz glass. In this case, it can be seen that the inner tube 5 is thicker than other portions in the vicinity of the end portion.

By doing so, the charge accumulated on the outer surface of the end thickness part 11 of the inner side pipe | tube 5 becomes small compared with the electric charge in the other part of the inner side pipe | tube 5, Therefore, it is inner side from the edge part of the outer electrode 4; Discharge to the internal electrode 3 outside the tube 5 is not transmitted, and surface discharge can be prevented.

Example 4

In Fig. 5, the fourth embodiment has the same basic idea as the third embodiment, and in this embodiment, a case in which the inner lead 6 connected to the inner electrode 3 extends to the inside of the inner tube 5; to be. In this embodiment, the additional dielectric 12 provided at the end of the inner tube 5 is provided on the inner surface of the inner tube 5.

The operation of preventing creeping discharge in the fourth embodiment is the same as in the third embodiment, except that the outer surface of the inner tube 5 is smoothed.

Example 5

6 shows Example 5, FIG. 6 (a) is a side cross-sectional view, and (b) is a cross-sectional view.

In FIG. 6, conductive members 13 such as metal rings and metal wires are wound around the ends of the inner tube 5, and the other ends 13a extend toward the inner wall direction of the discharge vessel 2. May be in contact with the discharge vessel 2.

In this embodiment, the charge accumulated on the outer surface of the end portion of the inner tube 5 escapes from the other end portion 13a to the discharge vessel 2 side via the conductive member 13, and consequently, on the outer surface of the end portion. Accumulated charge is reduced. Therefore, creeping discharge from the end of the outer electrode 4 to the inner electrode 3 outside the inner tube 5 is prevented.

In the excimer lamp of the present invention, an inner tube made of a dielectric material is provided on the outer circumference of the inner electrode, and two dielectric materials are interposed between the inner electrode and the outer electrode, so that the discharge is uniformly formed in the discharge space. easy. In addition, since arc-shaped discharge is not generated regardless of the urging property, the generation efficiency of excimer light is high, and the problem that the electrode burns and is not broken does not occur.

In addition, since the surface discharge prevention means is provided at the end of the inner tube, unwanted creeping discharge between the inner electrode and the outer electrode protruding from the inner tube is prevented, and the inner electrode and the outer electrode of the inner tube are prevented. It is possible to obtain stable discharge therebetween.

Claims (8)

A discharge container in which the gas for discharge is enclosed, an inner electrode which extends in the longitudinal direction of the inside of the discharge container and is hermetically sealed at the end of the discharge container, and an outer electrode disposed on the outer surface of the discharge container. In the excimer lamp, The inner electrode is covered with an inner tube made of a dielectric material whose at least one outer surface of the portion which discharges between the outer electrodes is discharged at least in the discharge space, The inner tube extends past the end of the corresponding outer electrode in the longitudinal direction, and prevents unwanted creepage discharge between the inner electrode and the outer electrode protruding from the inner tube at the end. An excimer lamp comprising a surface discharge prevention means. The excimer lamp according to claim 1, wherein the creepage discharge preventing means is a creepage distance extending means. The excimer lamp according to claim 2, wherein the creepage distance extending means is an enlarged diameter portion formed at an end of the inner tube. The excimer lamp according to claim 2, wherein the creepage distance extending means is a non-conductive partition plate provided on an outer periphery near the end of the inner tube. The excimer lamp according to claim 1, wherein the creepage discharge preventing means is a charge reducing means for reducing the charge accumulated on the outer surface near the end of the inner tube. 6. An excimer lamp according to claim 5, wherein said charge reducing means is an end thickness portion formed thicker than the other thickness in the vicinity of the inner tube end portion. The excimer lamp according to claim 5, wherein the charge reducing means is mounted on an outer surface near the end of the inner tube, and the other end is a conductive member facing the inner wall of the discharge vessel. The excimer lamp according to any one of claims 1 to 7, wherein an end portion of the discharge container is formed by a foil seal.

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