JPH10241633A - Dielectric barrier discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the manufacture of an inside electrode and improve adhesion thereof to an inside tube, while preventing cracks from being generated in the inside tube, if a lamp develops a high temperature while it is on, in the case of a dielectric barrier discharge lamp. SOLUTION: This discharge lamp has a substantially cylindrical double tube structure, wherein an outside tube 3 and an inside tube 2 are coaxially disposed, an outside electrode 5 being provided on an outside surface of the outside tube 3, an inside electrode 4 having a cutout over a whole length in the axial direction thereof being provided on an inside surface of the inside tube 2, gas for discharge which forms excimer molecules by a dielectric barrier discharge is filled in a discharge space 8 between the outside tube 3 and the inside tube 2. In this case, a surface-shaped elastic member 20 is disposed inside the inside electrode 4, so as to face on an inner surface of the inside electrode 4, and the inside electrode 4 is pressed against the inside tube 2 by its elastic force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called dielectric barrier discharge lamp in which excimer molecules are formed by a dielectric barrier discharge and light emitted from the excimer molecules is used. Used as an ultraviolet light source.

[0002]

2. Description of the Related Art As a technique related to the present invention, for example, Japanese Patent Application Laid-Open No. 1-144560 or US Pat.
No. 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 a 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, at least a part of a substantially cylindrical discharge vessel also serves as a dielectric of a dielectric barrier discharge,
It also states that the dielectric is transparent and emits light from the excimer molecules. Further, the outer tube and the inner tube are arranged coaxially 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.

[0004] Such a dielectric barrier discharge lamp has features not found in conventional low-pressure mercury lamps or high-pressure arc discharge lamps, for example, its central wavelength is 172 nm, 222 nm,
It emits ultraviolet light having a short wavelength of 308 nm, and selectively generates light of a single wavelength close to the line spectrum with high efficiency. As described above, if the outer shape is substantially cylindrical and the outer tube and the inner tube are coaxially arranged, commercially available quartz glass can be used for the discharge vessel, and the structure of the entire lamp is also reduced. It also has the feature of being simple and easy to manufacture.

On the other hand, as the inner electrode, a pipe-shaped metal tube is often used because of problems such as easiness in production and corrosion. However, in the case of a pipe-shaped metal tube, 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, so that the adhesion between the inner electrode and the inner tube becomes extremely poor, and the discharge space The disadvantage is that the amount of power supplied to the power supply varies.

In order to solve this problem, Japanese Patent Laid-Open Publication No.
No. 6770. This publication has a notch in the axial direction over the entire length of the inner electrode (a long section having a substantially C-shaped cross section),
A technique is disclosed in which the width of the notch is adjusted to bring the inner electrode into close contact with the inner tube. It is also disclosed that a helical spring is further used inside the inner electrode 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. Also, during lighting, the inner electrode and the inner tube are in a substantially molten state because they are at a very high temperature, and they tend to adhere to each other. However, cracks are likely to occur in the inner tube due to a difference in the coefficient of thermal expansion between them.

[0007]

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

[0009]

A dielectric barrier discharge lamp according to the present invention has a substantially cylindrical double tube structure in which an outer tube and an inner tube are coaxially arranged, and an outer electrode is provided on the outer surface of the outer tube. Is provided on the inner inner surface of the inner tube, the inner electrode having a notch over the entire length in the axial direction, and excimer molecules are formed by a dielectric barrier discharge in a discharge space between the outer tube and the inner tube. In a dielectric barrier discharge lamp filled with a discharge gas, a planar elastic member is disposed on an inner surface of the inner electrode, and the inner electrode is pressed against the inner tube by the elastic force. And

Further, the planar elastic member has a substantially C-shaped cross section, and a plurality of the planar elastic members are arranged at intervals along the longitudinal direction of the inner electrode.

Further, the planar elastic member has a substantially C-shaped cross section and is a long member extending along the longitudinal direction of the inner electrode.

Further, the planar elastic member has a substantially spiral shape in cross section, and a plurality of the planar elastic members are arranged at intervals along the longitudinal direction of the inner electrode.

Further, the planar elastic member has a substantially spiral shape in cross section, and has a long shape extending along the longitudinal direction of the inner electrode.

Further, the outer tube and the inner tube are coaxially arranged to form a substantially cylindrical double tube, and an outer electrode is provided on the outer surface of the outer tube, and the entire length in the axial direction is provided on the inner inner surface of the inner tube. A dielectric barrier discharge lamp in which a discharge gas for forming excimer molecules by dielectric barrier discharge is filled in a discharge space between the outer tube and the inner tube. Inside the inner electrode, a substantially brush-shaped electrode pressing member including a central axis extending substantially parallel to the inner electrode and a plurality of branches radially extending from the central axis toward the inner electrode is provided. .

Further, the outer tube and the inner tube are coaxially arranged to form a substantially cylindrical double tube, and an outer electrode is provided on the outer surface of the outer tube, and the entire length in the axial direction is provided on the inner inner surface of the inner tube. A dielectric barrier discharge lamp in which a discharge gas for forming excimer molecules by dielectric barrier discharge is filled in a discharge space between the outer tube and the inner tube. The inner electrode and the inner side have a pressing member for pressing the inner electrode in the direction of the inner tube, and the pressing member presses the inner tube via a plate-shaped member for preventing local pressing. .

The outer tube and the inner tube are coaxially arranged to form a substantially cylindrical double tube structure. An outer electrode is provided on the outer surface of the outer tube, and the inner surface of the inner tube extends over the entire length in the axial direction. An inner electrode having a notch is provided, and the discharge space between the outer tube and the inner tube is filled with a discharge gas for forming excimer molecules by a dielectric barrier discharge. A dielectric barrier discharge lamp comprising: a pressing member provided on an inner side of an electrode for pressing the inner electrode toward an inner tube; and the inner electrode is divided into a plurality of parts in the axial direction.

[0017]

According to the first aspect of the present invention, the sheet-like elastic member is disposed on the inner surface of the inner electrode so that the inner electrode can be pressed against the inner tube by its elastic force. For this reason, it is not possible to press the inner electrode against the inner tube by a helical spring as in the related art, but to press the inner electrode uniformly by a planar elastic member. As the planar elastic member, one having a substantially C-shaped cross section or one having a substantially spiral shape in cross section is applied, and a plurality of divided and arranged in the longitudinal direction of the inner tube, Can also be arranged.

According to the invention of claim 6 of the present invention,
On the inner side of the inner electrode, there is provided a substantially brush-like electrode pressing member comprising a central axis extending substantially parallel to the inner electrode and a number of branches radially extending from the central axis toward the inner electrode. Enables multipoint support by the tip.

According to the invention of claim 7 of the present invention,
Further on the inner surface of the inner electrode, there is a pressing member for pressing the inner electrode against the inner tube, and since this pressing member is interposed by a spacer member for preventing local pressing, the uniform pressing by the spacer member is achieved. Pressing becomes possible.
In this case, as the pressing member, a member having a substantially C-shaped cross section or a substantially spiral shape is used, and a helical spring or the like can be used.

According to the invention of claim 8 of the present invention,
On the inner side of the inner electrode, there is a pressing member that presses 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 can be supplemented, and the inner tube can be prevented from cracking.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The discharge vessel 1 has an inner tube 2 made of synthetic quartz glass.
And the outer tube 3 are coaxially arranged to form a double tube structure. Both ends of the inner tube 2 and the outer tube 3 are closed, and a discharge space 8 is formed therebetween. The discharge vessel 1 has, for example, a total length of 300.
mm, the inner tube 2 has an outer diameter of 16 mm, a wall thickness of 1 mm,
The outer tube 3 has an outer diameter of 26.5 mm and a thickness of 1 mm. In the discharge space 8, xenon gas is used as a discharge gas.
For example, 40 kPa is sealed. 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 of a dielectric barrier discharge and a function as a light extraction window, and an outer electrode 5 is provided on an outer surface.
The outer electrode 5 is formed by inserting the discharge vessel 1 in 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 are provided at both ends of the inner electrode 4 to prevent slipping out.
And a projection 12 are provided. 13 is the lead 9 for the discharge vessel 1
It is a connector that penetrates inside and outside.

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 efficiently supplied. 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 pieces 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.

FIG. 3 shows another specific example of the planar elastic member.
FIG. 4A is a cross-sectional view in the longitudinal direction (axial direction), and FIG.
The figure is a cross-sectional view cut in a radial direction. This embodiment differs from FIG. 2 in that the planar elastic member 20 is not divided into a plurality of parts, but is elongated like the inner tube 2 and extends in the longitudinal direction.

FIG. 4 shows another specific example of the planar elastic member.
FIG. 4A is a cross-sectional view in the longitudinal direction (axial direction), and FIG.
The figure is a cross-sectional view cut in a radial direction. This embodiment differs from FIG. 2 in that it has a substantially spiral shape in which the planar elastic member 20 partially overlaps. Also, in the figure, it is divided into a plurality in the longitudinal direction,
A long one may be used.

Further, a planar elastic member as shown in FIGS. 5 and 6 can be applied. The elastic member having such a shape has an advantage that the close contact 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 increases, and the insertion operation can be easily performed in the manufacturing process. is there.

FIG. 7 shows an embodiment of the invention according to claim 6. (A) The figure is a cross-sectional view in the longitudinal direction (axial direction),
(B) is a cross-sectional view taken in a radial direction. Inside the inner electrode 4, there is provided a substantially brush-shaped electrode pressing member 70 including a central axis 70 extending substantially parallel to the inner electrode 4 and a large number of branches 71 radially extending from the central axis toward the inner electrode. The branch 71 is slightly longer than the shortest distance between the central axis 71 and the inner electrode 4.
The inner electrode 4 is pressed against the inner tube 2 by the elastic force of 1. Here, since a large number of the branch portions 71 exist radially from the central axis 70, the pressing function itself can be substantially the same as pressing with a planar member. That is, by pressing the inner electrode 4 against the inner tube 2 by such multi-point support, it is not possible to press the inner electrode against the inner tube by the helical spring disclosed in the prior art, but to press uniformly. It becomes possible. Here, as a specific example, the central shaft 71 and the branch portion 72 are integrally formed of stainless steel, and the branch portions 72 are present at intervals of 1 mm.

FIG. 8 shows an embodiment of the present invention. (A) The figure is a cross-sectional view in the longitudinal direction (axial direction),
(B) is a cross-sectional view taken in a radial direction. A pressing member 81 is provided on the inner surface of the inner electrode 4 via a spacer member 80. The spacer member 80 is made of, for example, stainless steel and has a thickness of 0.15 mm. Through such a spacer member 80, the pressing of the inner electrode 4 against the inner tube 2 can be made uniform rather than locally. The pressing member 81 can use a helical spring, but is not particularly limited as long as the inner electrode 4 can be pressed against the inner tube 2. The elastic member shown in FIGS. Is possible.

FIG. 9 shows an embodiment of the invention according to claim 8. (A) The figure is a cross-sectional view in the longitudinal direction (axial direction),
(B) is a cross-sectional view taken in a radial direction. On the inner surface of the inner electrode 4, there is a pressing member 90 for pressing the inner electrode 4 in the direction of the inner tube 2. 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. Such a gap can suitably compensate for the thermal expansion of the divided electrodes 41 and 42, and can prevent cracks in the inner tube 2. 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, thermal expansion is performed at the space. Can be suitably supplemented. Further, the electrode 4 loses electrical connection by being divided, but 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, not only the spiral spring but also the elastic member shown in FIGS. Is possible. In the present invention, it is also possible to use a spacer member as shown in FIG. In this case, the spacer member may be used as a conductive means for electrical connection.

FIG. 10 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.
No. 6770, that is, a substantially C-shaped one having a notch or a pipe-shaped metal tube can also be used.

[0031]

According to the first aspect of the present invention, the sheet-like elastic member is disposed facing the inner surface of the inner electrode, and the inner electrode can be pressed against the inner tube by the elastic force. For this reason, it is possible to uniformly press the inner electrode, instead of locally pressing the inner electrode to the inner tube by the helical spring as in the related art, thereby preventing the inner tube from being cracked.

According to the invention of claim 6 of the present invention,
The inner surface of the inner electrode has a substantially brush-like electrode holding member including a central axis extending substantially parallel to the inner electrode and a number of branches radially extending from the central axis toward the inner electrode. The spring makes it possible to uniformly press the inner electrode, instead of locally pressing the inner electrode against the inner tube, thereby preventing the inner tube from being cracked.

According to the invention of claim 7 of the present invention,
On the inner surface of the inner electrode, there is a pressing member for pressing the inner electrode against the inner tube, and since this pressing member is interposed by a spacer member for preventing local pressing, uniform pressing is performed by the spacer member. Becomes possible.

According to the invention of claim 8 of 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, so that the thermal expansion of the inner electrode is caused by the gap between the electrodes. It can compensate and prevent cracking of the inner tube.

[Brief description of the drawings]

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

FIG. 2 is a schematic view of an inner electrode of a dielectric barrier discharge lamp according to the present invention.

FIG. 3 is a schematic view of an inner electrode of the dielectric barrier discharge lamp according to the present invention.

FIG. 4 is a schematic view of an inner electrode of the dielectric barrier discharge lamp according to the present invention.

FIG. 5 is a schematic view of an inner electrode of the dielectric barrier discharge lamp according to the present invention.

FIG. 6 is a schematic view of an inner electrode of a dielectric barrier discharge lamp according to the present invention.

FIG. 7 is a schematic view of an inner electrode of the dielectric barrier discharge lamp according to the present invention.

FIG. 8 is a schematic view of an inner electrode of the dielectric barrier discharge lamp according to the present invention.

FIG. 9 is a schematic view of an inner electrode of the dielectric barrier discharge lamp according to the present invention.

FIG. 10 is a schematic diagram of an inner electrode of a dielectric barrier discharge lamp according to the present invention.

[Explanation of symbols]

 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 70: pressing member 80: plate-shaped spacer Member 81: pressing member 90: pressing member 91: cap 92: cap 110: divided pressing member 120: divided spacer member

Continued on the front page (72) Inventor Hiromitsu Matsuno 1194 Sado Bessho-cho, Himeji-shi, Hyogo Ushio Electric Co., Ltd.

Claims (8)

[Claims] A substantially cylindrical double tube structure in which an outer tube and an inner tube are coaxially arranged, an outer electrode is provided on an outer surface of the outer tube, and an inner inner surface of the inner tube extends over the entire length in the axial direction. A dielectric barrier discharge lamp, wherein an inner electrode having a notch is provided, 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; A dielectric barrier discharge lamp, wherein a planar elastic member is disposed inside the electrode so as to face the inner surface of the inner electrode, and the elastic force presses the inner electrode against the inner tube. 2. The dielectric according to claim 1, wherein said planar elastic member has a substantially C-shaped cross section, and a plurality of said planar elastic members are arranged at intervals along the longitudinal direction of the inner electrode. Body barrier discharge lamp. 3. The dielectric barrier according to claim 1, wherein the planar elastic member has a substantially C-shaped cross section and is elongated in length along the longitudinal direction of the inner electrode. Discharge lamp. 4. The dielectric according to claim 1, wherein said planar elastic member has a substantially spiral shape in cross section, and a plurality of said planar elastic members are arranged at intervals along the longitudinal direction of the inner electrode. Barrier discharge lamp. 5. The dielectric barrier discharge according to claim 1, wherein the planar elastic member has a substantially spiral shape in cross section, and has a long shape extending along the longitudinal direction of the inner electrode. lamp. 6. An outer tube and an inner tube are arranged coaxially to form a substantially cylindrical double tube structure, an outer electrode is provided on an outer surface of the outer tube, and an entire inner length of the inner tube is provided on an inner inner surface of the inner tube. A discharge electrode for forming excimer molecules by a dielectric barrier discharge in a discharge space between the outer tube and the inner tube. Inside the inner electrode, a substantially brush-shaped electrode pressing member including a central axis extending substantially parallel to the inner electrode and a plurality of branches radially extending from the central axis toward the inner electrode is provided. Dielectric barrier discharge lamp. 7. 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 entire length of the inner tube is provided on an inner inner surface of the inner tube. A discharge electrode for forming excimer molecules by a dielectric barrier discharge in a discharge space between the outer tube and the inner tube. Inside the inner electrode, there is a pressing member for pressing the inner electrode in the direction of the inner tube, and this pressing member presses the inner tube via a spacer member for preventing local pressing. Body barrier discharge lamp. 8. 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 of the inner tube is provided on an inner inner surface of the inner tube. A dielectric barrier discharge lamp in which an inner electrode having a notch over its entire length is provided and a discharge gas forming excimer molecules by a dielectric barrier discharge in a discharge space between the outer tube and the inner tube, A dielectric barrier discharge lamp, comprising a pressing member for pressing the inner electrode in the direction of the inner tube inside the inner electrode, wherein the inner electrode is divided into a plurality in the axial direction.