JP2004087507A - Dielectric barrier discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric barrier discharge lamp in which an inner electrode is easy to be manufactured and cracks do not occur in an inner tube even if the lamp reaches a high temperature during lighting by improving adhesion with the inner tube. <P>SOLUTION: The dielectric barrier discharge lamp 1 has a nearly cylindrical double-walled pipe structure wherein an outer tube 3 and the inner tube 2 are coaxially arranged, and an outer electrode 5 is provided on the outside surface of the outer tube 3 and the inner electrode 4 is provided on the inner face of the inner tube 2, and discharge gas which forms an excimer molecule by dielectric barrier discharge is filled in the discharge space between the outer tube 3 and the inner tube 2. The inner electrode 4 is split into a plurality of pieces in its axial direction and a pressing member 20 for depressing the inner electrode 4 in the direction of the inner tube 2 is provided, and the pressing member 20 has an electric connection function of the split inner electrodes 4. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a so-called dielectric barrier discharge lamp that forms excimer molecules by dielectric barrier discharge and uses light emitted from the excimer molecules, and is used, for example, as an ultraviolet light source for a photochemical reaction.

技術 As a technique related to the present invention, there is, for example, Japanese Patent Application Laid-Open No. 1-144560 or US Patent No. 9,837,484. It describes a radiator that fills a discharge vessel with a gas that produces excimer molecules and extracts light emitted from the excimer molecules by dielectric barrier discharge, ie, a dielectric barrier discharge lamp. This dielectric barrier discharge lamp is also called an ozonizer discharge or a silent discharge, and is described in the Institute of Electrical Engineers of Japan, revised edition, “Discharge Handbook”, June 2001, 7th reprint, 7th edition, page 263.

In this document, it is described that at least a part of a substantially cylindrical discharge vessel also serves as a dielectric of a dielectric barrier discharge, and that the dielectric is transparent and emits light from excimer molecules. Is done. Further, the outer tube and the inner tube are coaxially arranged as a double tube, a mesh electrode is provided on the outer surface of the outer tube, and the inner electrode is provided on the inner surface of the inner tube. It is also described that a dielectric barrier discharge is performed in the discharge space.

Such a dielectric barrier discharge lamp has features not found in conventional low-pressure mercury lamps and high-pressure arc discharge lamps, for example, it emits ultraviolet light having a short wavelength of 172 nm, 222 nm, and 308 nm, and is close to a line spectrum. Light of a single wavelength is selectively generated with high efficiency. Further, as described above, if the outer shape is substantially cylindrical and the outer tube and the inner tube are coaxially arranged, a commercially available quartz glass can be used for the discharge vessel, and the entire lamp has a structure. It also has the feature of being simple and easy to manufacture.

On the other hand, a pipe-shaped metal tube is often used for the inner electrode because of problems such as ease of manufacturing and corrosion. However, in the case of a pipe-shaped metal tube, since the tolerance of the inner diameter of a commercially available quartz glass tube used as the inner tube is as large as about ± 0.5 mm, the adhesion between the inner electrode and the inner tube is significantly deteriorated, and the discharge space is reduced. The disadvantage is that the amount of power supplied to the power supply varies.

特 開 To solve this problem, there is JP-A-8-96770. This publication discloses a technique in which a notch is formed in the axial direction over the entire length of the inner electrode (a long section is substantially C-shaped), and the inner electrode is brought into close contact with the inner tube by adjusting the width of the notch. Disclosed. It is also disclosed that a helical spring is further used inside the inner electrode in order to satisfactorily press the inner electrode against the inner tube. However, during the operation of the lamp, the inner electrode (for example, made of aluminum) becomes extremely hot and becomes soft, and when the inner electrode is pressed by a helical spring, the inner electrode is locally formed into an inner tube (made of quartz glass or the like). Pressing may cause cracks in the inner tube. In addition, during lighting, since the temperature is extremely high, the inner electrode and the inner tube are substantially in a molten state, and the two tend to adhere to each other. However, cracks are likely to occur in the inner tube due to a difference in thermal expansion coefficient between the two.

Therefore, an object of the present invention is to provide a dielectric barrier discharge lamp as described below.
1. The inner electrode is easy to manufacture and has good adhesion to the inner tube.
2. The inner tube must not crack even if the lamp becomes hot during operation.

In the dielectric barrier discharge lamp according to the present invention, an outer tube and an inner tube are coaxially arranged to form a substantially cylindrical double tube structure, an outer electrode is provided on an outer surface of the outer tube, and an inner electrode is provided inside the inner tube. In a dielectric barrier discharge lamp, an inner electrode is provided on an inner surface, and a discharge gas for forming excimer molecules by a dielectric barrier discharge is filled in a discharge space between the outer tube and the inner tube. It is divided into a plurality in the axial direction, and has a pressing member for pressing the inner electrode in the direction of the inner tube inside the inner electrode, and the pressing member electrically connects the divided inner electrodes to each other. It has a connection function.

Further, the outer tube and the inner tube are coaxially arranged to form a substantially cylindrical double tube structure, an outer electrode is provided on an outer surface of the outer tube, and an inner electrode is provided on an inner inner surface of the inner tube. In a dielectric barrier discharge lamp filled with a discharge gas that forms excimer molecules by a dielectric barrier discharge in a discharge space between an outer tube and an inner tube, the inner electrode is divided into a plurality in the axial direction. A pressing member that presses the inner electrode in the direction of the inner tube and a spacer having an electrical connection function between the inner electrodes divided between the pressing member and the inner electrode are provided inside the inner electrode. It is characterized by being arranged.
Further, the spacer is divided into a plurality in the axial direction, and a position where the spacer is divided is different from a position where the inner electrode is divided.

According to the present invention, the inner surface of the inner electrode has a pressing member for pressing the inner electrode in the direction of the inner tube, and the inner electrode is divided into a plurality in the axial direction. The gap between the electrodes can be compensated for, and the inner tube can be prevented from cracking.

FIG. 1 shows a basic configuration of a dielectric barrier discharge lamp.
The discharge vessel 1 has a double tube structure in which an inner tube 2 and an outer tube 3 made of synthetic quartz glass are coaxially arranged, and both ends of the inner tube 2 and the outer tube 3 are closed, and a discharge space is provided therebetween. 8 are formed. The discharge vessel 1 has, for example, a total length of 300 mm, the inner tube 2 has an outer diameter of 16 mm and a wall thickness of 1 mm, and the outer tube 3 has an outer diameter of 26.5 mm and a wall thickness of 1 mm. Xenon gas, for example, 40 kPa is filled in the discharge space 8 as a discharge gas. The inner tube 2 is provided with an inner electrode 4 which is a light reflecting plate and functions as an electrode for dielectric barrier discharge. The outer tube 3 has both a function as a dielectric for the dielectric barrier discharge and a function as a light extraction window, and an outer electrode 5 is provided on the outer surface. The outer electrode 5 is formed by inserting the discharge vessel 1 into a metal wire that is seamlessly knitted in a cylindrical shape, has a net shape, and can emit light from between meshes. At one end of the discharge space 8, a storage chamber 7 for storing a getter 6 containing barium as a main component is provided, and the getter 6 removes an impurity gas (for example, water) in the discharge space 8 to stabilize the discharge. Let it. Leads 9 are connected to the inner electrode 4 and the outer electrode 5, and each lead 9 is connected to an AC power supply 10. Caps 11 and protrusions 12 are provided at both ends of the inner electrode 4 to prevent slipping out. Reference numeral 13 denotes a connector for passing the lead 9 inside and outside the discharge vessel 1.

Fig. 2 shows the inside of the inner tube 2. (A) is a cross-sectional view in the longitudinal direction (axial direction), and (b) is a cross-sectional view cut in a radial direction. An inner electrode 4 made of a semicircular metal is provided on the inner surface of the inner tube 2. Such an inner electrode 4 can be easily manufactured even if the outer diameter is small, and can improve the adhesion to the inner tube 2 even if the inner diameter of the inner tube 2 slightly varies. In addition, power is supplied efficiently. The inner electrode 4 in this embodiment is formed by, for example, bending an aluminum foil having a thickness of 0.15 mm. A planar elastic member 20 is disposed inside the inner electrode 4. The surface elastic member 20 is made of, for example, stainless steel, but the material is not particularly limited, and a material having elasticity and easy to process is applied. The planar elastic member 20 has a substantially C-shaped cross section having a cutout in part to exert an elastic force, and is divided into a plurality of parts inside the inner tube 2 and arranged. By using such a planar elastic member 20, the inner electrode 4 can be suitably brought into close contact with the inner tube 2.

Further, the planar elastic member of the present invention has a structure as shown in FIG. 3 (FIG. 4 (b) of the original application), FIG. 4 (FIG. 5 of the original application), and FIG. 5 (FIG. 6 of the original application). Is also good. In particular, if the elastic member has the shape shown in FIGS. 4 and 5, the adhesion between the inner tube and the inner electrode can be made to function well, and at the same time, the handleability of the elastic member itself is increased, and the insertion work can be easily performed in the manufacturing process. There is an advantage that can be.

FIG. 6 (FIG. 9 of the original application) shows an embodiment of the present invention. (A) is a cross-sectional view in the longitudinal direction (axial direction), and (b) is a cross-sectional view cut in a radial direction. A pressing member 90 for pressing the inner electrode 4 toward the inner tube 2 is provided on the inner surface of the inner electrode 4. The inner electrode 4 is divided into a plurality in the axial direction, and a gap of, for example, about 3 mm is provided between the divided electrodes 41 and 42. Caps 91 and 92 for preventing the electrodes from coming off are disposed at both ends of the inner electrode. With such a gap, thermal expansion of the divided electrodes 41 and 42 can be suitably compensated, and cracks in the inner tube 2 can be prevented. Supplementally, the conventional inner electrode 4 cannot be expanded in the longitudinal direction because it has the caps 91 and 92 at both ends thereof. However, since the space is provided as in the present invention, the thermal expansion is performed at the space. Can be suitably supplemented. Further, the electrode 4 is divided so that electrical connection is lost. However, such a problem can be easily solved by providing an appropriate conducting means between the divided electrodes. Also in the present invention, the pressing member 90 is not particularly limited. If the inner electrode 4 can be pressed against the inner tube 2, the pressing member 90 is not limited to the helical spring and is shown in FIGS. 2, 3, 4, and 5. It is possible to apply elastic members. In the present invention,

FIG. 7 (FIG. 10 of the original application) shows another embodiment of the present invention. (A) is a cross-sectional view in the longitudinal direction (axial direction), and (b) is a cross-sectional view cut in a radial direction. In this embodiment, both the inner electrode 4 and the spacer member 110 are divided in the longitudinal direction. In this case, the position to be divided for electrical connection is different between the inner electrode 4 and the spacer member 110. Such a structure is particularly effective when the entire discharge vessel is long.

In the above embodiment, two semicircular tubular members are used as the inner electrodes. However, a structure as shown in Japanese Patent Application Laid-Open No. 8-96770, that is, a substantially C-shaped member having a notch or a pipe is used. Shaped metal tubes can also be used.

1 is a schematic view of a dielectric barrier discharge lamp according to the present invention. 1 is a schematic view of an inner electrode of a dielectric barrier discharge lamp according to the present invention. 1 is a schematic view of an inner electrode of a dielectric barrier discharge lamp according to the present invention. 1 is a schematic view of an inner electrode of a dielectric barrier discharge lamp according to the present invention. 1 is a schematic view of an inner electrode of a dielectric barrier discharge lamp according to the present invention. 1 is a schematic view of a dielectric barrier discharge lamp according to the present invention. 1 is a schematic view of a dielectric barrier discharge lamp according to the present invention.

Explanation of reference numerals

1: discharge vessel 2: inner tube 3: outer tube 4: inner electrode 5: outer electrode 6: getter 20: planar elastic member 41: divided electrode 42: divided electrode 90: pressing member 91: cap 92: Cap 110: divided pressing member 120: divided spacer member

Claims (3)

An outer tube and an inner tube are coaxially arranged to form a substantially cylindrical double tube structure, an outer electrode is provided on an outer surface of the outer tube, and an inner electrode is provided on an inner inner surface of the inner tube. In a dielectric barrier discharge lamp filled with a discharge gas for forming excimer molecules by a dielectric barrier discharge in a discharge space between the inner tube and the inner tube,
The inner electrode is divided into a plurality in the axial direction, and has a pressing member for pressing the inner electrode in the direction of the inner tube inside the inner electrode, and the pressing member is a divided inner electrode. A dielectric barrier discharge lamp having an electrical connection function between them. An outer tube and an inner tube are coaxially arranged to form a substantially cylindrical double tube structure, an outer electrode is provided on an outer surface of the outer tube, and an inner electrode is provided on an inner inner surface of the inner tube. In a dielectric barrier discharge lamp filled with a discharge gas for forming excimer molecules by a dielectric barrier discharge in a discharge space between the inner tube and the inner tube,
The inner electrode is divided into a plurality in the axial direction, and a pressing member for pressing the inner electrode in the direction of the inner tube inside the inner electrode, and is divided between the pressing member and the inner electrode. A dielectric barrier discharge lamp, wherein a spacer having an electrical connection function between the inner electrodes is arranged. 3. The dielectric barrier discharge lamp according to claim 2, wherein the spacer is divided into a plurality in the axial direction, and a position where the spacer is divided is different from a position where the inner electrode is divided.

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