JPH0785837A - Dielectric barrier discharge lamp - Google Patents

Abstract

PURPOSE:To provide spatial uniformity and temporal stability of light output and improve light emitting efficiency by making the average thickness of electrode terminal parts of conductive net-like electrodes thicker than the average thickness of the conductive net-like electrodes. CONSTITUTION:A net-like electrode 4 is prepared by knitting a metal wire 23 into a seamless cylindrical shape and repeatedly forming loops in the circumferential direction of the cylinder. The net-like electrode 4 closely attached to the outside of an outside pipe 3 is formed by inserting a discharge container 1 into the cylindrical metal net and pulling the net in the axial direction of a lamp. At that time, the average thickness of the electrode terminal parts 10a, 10b of the net-like electrode 4 is made thicker than the average thickness of the net-like electrode 4. For that, stainless steel wires 12a, 12b are wound on the electrode terminal parts 10a, 10b of the electrode 4 in the axial direction of the lamp and an electrode lead wire 9 is connected to the stainless steel wire 12a. As a result, spatial uniformity of the light output of a low electric power discharge lamp is improved and light emitting efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is, for example, a kind of discharge lamp used as an ultraviolet light source for photochemical reaction, which forms excimer molecules by dielectric barrier discharge and utilizes the light emitted from the excimer molecules. To improve the so-called dielectric barrier discharge lamp.

[0002]

2. Description of the Related Art As a technique related to the present invention, there is, for example, Japanese Unexamined Patent Publication No. 2-7353, in which at least a discharge vessel is filled with a discharge gas for forming excimer molecules, and Excimer molecules are formed by body barrier discharge (also known as ozonizer discharge or silent discharge. See the revised edition "Discharge Handbook" published by The Institute of Electrical Engineers of Japan, June 1993, 7th edition, page 263), and the light emitted from the excimer molecule is formed. A radiator to be taken out, that is, a dielectric barrier discharge lamp is described, wherein the discharge vessel is cylindrical, and at least a part of the discharge vessel also serves as a dielectric of the dielectric barrier discharge. At least a part of the light-transmitting dielectric material is transparent to light emitted from the excimer molecule, and a conductive mesh electrode is provided on at least a part of the light-transmitting dielectric. Structure obtained dielectric barrier discharge lamp is described. The dielectric barrier discharge lamp as described above is useful because it has various features that conventional low-pressure mercury discharge lamps and high-pressure arc discharge lamps do not have. However, the dielectric barrier discharge lamp as described above,
There is a problem that the spatial uniformity and temporal stability of the light output are not always sufficient and the luminous efficiency is not always sufficient.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cylindrical dielectric barrier discharge lamp which has good spatial uniformity and temporal stability of light output and high luminous efficiency. Is.

[0004]

DISCLOSURE OF THE INVENTION It is an object of the present invention to fill at least a discharge vessel with a discharge gas for forming excimer molecules by dielectric barrier discharge, and at least a part of the discharge vessel is the dielectric barrier discharge. Of the discharge vessel, at least a part of which is transparent to the light emitted from the excimer molecule, and at least a part of the dielectric has a conductive thin film electrode or a conductive mesh electrode. In the dielectric barrier discharge lamp provided with, the thickness of the electrode end portion of the conductive thin film electrode or conductive mesh electrode,
This is achieved by constructing the conductive thin film electrode or the conductive reticulated electrode so as to exceed the average thickness. Further, the outer shape of the discharge vessel is substantially cylindrical, and the conductive thin film electrode or the conductive reticulated electrode is provided outside the discharge vessel, and the conductive thin film electrode or the electrode end of the conductive reticulated electrode is provided. A structure in which at least one selected from a wire, a stranded metal wire, a metal tape, and a metal mesh tape is wound, and further, the cylinder made of a seamless cylindrical conductive mesh having elasticity in the axial direction. The object of the present invention can be further achieved by forming the end portion of the reticulated mesh electrode into a bent configuration.

Further, an electrode lead wire is connected to at least one member selected from the wire, the metal twisted wire, the metal tape, and the metal mesh tape wound around the end of the cylindrical conductive mesh. Alternatively, the object of the present invention can be further achieved by applying a conductive paste to the end of the conductive thin film electrode or the conductive mesh electrode.

[0006]

[Function] Dielectric barrier discharge is described in the "Discharge Handbook"
As described in (1), it is a large collection of minute discharge plasmas (hereinafter referred to as microplasma) having a very small plasma diameter and a very short discharge duration. We have found that at least the discharge vessel is filled with a discharge gas that forms excimer molecules by dielectric barrier discharge, and at least a part of the discharge vessel also serves as a dielectric of the dielectric barrier discharge, and at least the discharge vessel A part of the dielectric barrier discharge lamp is transparent to light emitted from the excimer molecule, and in a dielectric barrier discharge lamp in which at least a part of the dielectric is provided with a conductive thin film electrode or a conductive mesh electrode, Output stability, spatial uniformity, and luminous efficiency are affected by the ends of the conductive thin film electrode or conductive mesh electrode provided on the dielectric.
Furthermore, by configuring the thickness of the end portion of the conductive thin film electrode or the conductive reticulated electrode so as to exceed the average thickness of the conductive thin film electrode or the conductive reticulated electrode, it is possible to solve the above problems. Discovered experimentally.

Although the mechanism of improving the temporal stability of the light output, the spatial uniformity, and the luminous efficiency is not clear, it is considered as follows. That is, since the conductive thin film electrode or the conductive mesh electrode is thin in the first place and its end portion is likely to have a knife blade shape or a needle shape, the electric field strength is likely to be nonuniform and large at the end portion. Therefore, at the terminal end of the conductive thin film electrode or the conductive mesh electrode, a creeping discharge-like discharge occurs in an atmosphere gas such as air instead of the discharge gas, and further, microplasma concentrates at the electrode end. Therefore, many occur. As a result, the discharge becomes unstable, and the light output at the electrode end portion becomes large, that is, the temporal fluctuation of the light output becomes large, and the spatial uniformity of the light output deteriorates. Further, when a discharge like a creeping discharge is generated in an atmospheric gas such as air or when microplasma is excessively concentrated, the luminous efficiency is also reduced.

At least the discharge vessel is filled with a discharge gas that forms excimer molecules by dielectric barrier discharge,
At least a portion of the discharge vessel also serves as a dielectric of the dielectric barrier discharge, and at least a portion of the discharge vessel is light transmissive to light emitted from the excimer molecules,
In a dielectric barrier discharge lamp in which a conductive thin film electrode or a conductive mesh electrode is provided on at least a part of the dielectric, the average thickness of the electrode end of the conductive thin film electrode or the conductive mesh electrode is defined as the conductive thickness. If it is configured to exceed the average thickness of the conductive thin film electrode or the conductive mesh electrode,
The concentration of the electric field strength at the end portions of the electrodes is reduced, so that the electric field strength becomes relatively uniform and the strength thereof becomes weak. As a result, the spatial uniformity of the light output, the temporal fluctuation of the light output, and the luminous efficiency are improved. The electrode end portion in the present invention means an electrode end portion, that is, an electrode portion having a length equal to or shorter than the discharge gap length of the dielectric barrier discharge from the portion where the electrode along the dielectric of the dielectric barrier discharge is interrupted.

The outer shape of the discharge vessel is substantially cylindrical, the conductive thin film electrode or the conductive reticulated electrode is provided outside the discharge vessel, and the electrode end of the conductive thin film electrode or the conductive reticulated electrode is provided. Wire, metal stranded wire, metal tape,
If at least one selected from the metal mesh tape is wound, or if the end portion of the cylindrical mesh electrode is bent, the thickness of the electrode end portion can be uniformly increased by a simple operation. It will be possible. Further, an electrode lead wire is attached to at least one member selected from the wire, the metal strand, the metal tape, and the metal mesh tape wound around the electrode end of the conductive thin film electrode or the conductive mesh electrode. When connected, the conductive thin film electrode or the conductive reticulated electrode is reliably connected with high mechanical strength, so that a highly reliable dielectric barrier discharge lamp can be obtained.

When the conductive reticulated electrode is composed of a seamless cylindrical conductive net having elasticity in the axial direction, a substantially cylindrical discharge container is inserted into the cylindrical conductive net, and then the cylinder is closed. When the conductive mesh is pulled in the axial direction, the radius of the conductive mesh electrode is contracted, and the light-transmitting dielectric having a substantially cylindrical shape and the conductive mesh electrode are completely adhered to each other, so that a void is formed in a part thereof. As a result, an extra discharge does not occur, the extra discharge does not generate a harmful compound in the vicinity of the lamp, and the discharge becomes stable and the light output becomes stable. Further, the luminous efficiency is increased. That is, the flat mesh electrode is not rolled to form a suture line portion in the conductive mesh electrode, and the conductive mesh electrode has a substantially cylindrical shape. It is possible to obtain a dielectric barrier discharge lamp which is sufficiently uniform on the surface, resulting in spatially uniform discharge, stable discharge, and stable light output.

When a conductive paste containing silver, gold, nickel, carbon or the like as a main component is applied to the electrode end portion of the conductive thin film electrode or the conductive mesh electrode, the electrode end can be formed in an arbitrary shape by a simple operation. The thickness of the portion can be increased, and therefore the uniformity of the electric field strength can be further improved. When a conductive paste is applied to a portion to which the electrode lead wire is connected, at least one member selected from the wire wound around the end of the electrode, the metal strand, the metal tape, and the metal mesh tape is electrically conductive. Since the thin film electrode or the conductive mesh electrode is connected with high mechanical strength and reliably, a highly reliable dielectric barrier discharge lamp can be obtained.

[0012]

1 is a schematic view of a coaxial cylindrical dielectric barrier discharge lamp according to a first embodiment of the present invention. Discharge vessel 1
Is made of quartz glass having a total length of about 150 mm, and an inner tube 2 having an outer diameter of 14 mm and an outer tube 3 having an inner diameter of about 25 mm are coaxially arranged to form a hollow cylinder. The outer tube 3 also serves as a dielectric barrier for dielectric barrier discharge and a light extraction window member, and a metal mesh electrode 4 that transmits light is provided on the outer surface. On the outer surface of the inner tube 2, a 0.005 mm-thick aluminum vapor-deposited film electrode 5 also serving as a light reflection plate is provided. The distance of the discharge gap 7 is 5.5 mm.
A barium getter 6 is provided at one end of the discharge vessel 1.

The mesh electrode 4, as shown in a part of FIG. 2, is a seamless metal wire 23 woven into a cylindrical shape, and loops are repeatedly formed in the circumferential directions 22a and 22b of the cylinder. The structure is a cylindrical net, the diameter of the metal wire is 0.1mm
In Monel, the areas of the large mesh 24 and the small mesh 25 are about 2 and 1 mm 2, respectively.
By inserting the discharge vessel 1 into the cylindrical metal mesh and pulling it in the axial direction of the lamp, the mesh electrode 4 was formed in close contact with the outside of the outer tube 3. That is, each of the cylindrical mesh electrodes 4 has the outer tube 3 according to the above configuration of the present invention.
It adhered without any gap. Stainless steel wires 12a and 12b having a diameter of 0.1 mm were wound around the electrode ends 11a and 11b of the cylindrical net electrode 4 for 3 mm in the axial direction of the lamp. The electrode lead wire 9 was connected to the stainless wire 12a, and the silver paste 13 was applied thereon with a thickness of about 0.5 mm. Silver pastes 14a and 14b having a thickness of about 0.5 mm and a length of 5 are formed on the electrode ends 10a and 10b of the inner electrode 5.
applied over mm. The discharge gap 7 of the discharge container was filled with 300 Torr of xenon gas as a discharge gas. Discharged with a power of 8 watts at a frequency of 20 kHz at a power of 2 watts per 1 cm of lamp length, a dielectric barrier discharge lamp with improved spatial uniformity of light output, temporal fluctuation of light output, and luminous efficiency was obtained. Was obtained.

A schematic view of a coaxial cylindrical dielectric barrier discharge lamp according to a second embodiment of the present invention is shown in FIG. The structure is the same as that of the first embodiment except the structure of the electrode end portions 11a and 11b of the cylindrical net electrode 4. The electrode ends of the cylindrical net electrode 4 are bent and overlapped to form bent portions 30a and 30b,
Nickel pastes 31a and 31b were applied thereon with a thickness of about 1 mm. A dielectric barrier discharge lamp having improved spatial uniformity of light output, temporal fluctuation of light output, and luminous efficiency was obtained.

FIG. 4 is a schematic view of a disk-shaped dielectric barrier discharge lamp according to the third embodiment of the present invention. Diameter 100m
m, a flat plate dielectric 41 made of a synthetic quartz glass plate having a thickness of 1.5 mm, and a flat plate discharge vessel member 4 made of aluminum
A disk-shaped discharge container 49 is formed by 5 and the cylindrical quartz glass 46. The flat plate-shaped dielectric 41 also serves as a dielectric for a dielectric barrier discharge and as a light extraction window member, and a stainless steel wire having a diameter of 0.1 mm is 2 mm on the outer surface thereof.
A metal net electrode 43 having a diameter of 80 mm and having a structure in which it is knitted orthogonally at intervals is provided. The internal electrode is an electrode 44a made of an aluminum rod having a diameter of 1 mm attached to the center of the flat discharge vessel member 45, and an electrode made of an aluminum ring having a thickness of 1 mm attached to the flat discharge vessel member 45 coaxially with the electrode 44a. It is composed of 44b and 44c. The electrodes 44a, 44b, 44c also serve as a reinforcing member against the atmospheric pressure of the flat plate-shaped dielectric 1. Electrode 4
4a, 44b, and 44c are only in contact with the flat plate dielectric 41, and are not mechanically fixed to the flat plate dielectric 41. The electrodes 44a, 44b, 44c and the portion of the flat plate discharge vessel member 45 facing the discharge space were covered with a dielectric 40 made of MgF ₂ . Electrode end 48 of metal mesh electrode 43
Further, a stainless ring 50 having an inner diameter of 75 mm, an outer diameter of 85 mm and a height of 2 mm was provided in electrical contact with the metal mesh electrode 43. The ring 50 was fixed to the flat plate-shaped dielectric 41 by using a silicone rubber adhesive 51.

As a discharge gas, 350 Torr of xenon gas is sealed in the space 47, and the electrode 43 and the electrodes 44a, 4
When an AC voltage is applied by the power source 8 between 4b and 44c, a creeping discharge plasma 52 is generated in the vicinity of the plate-shaped dielectric 41, and ultraviolet rays having a maximum value at a wavelength of 172 nm and its vicinity from the xenon excimer molecule are efficient. Well radiated,
A compact dielectric barrier discharge lamp with improved spatial uniformity of light output, temporal fluctuation of light output, and luminous efficiency was obtained.

[0017]

As described above, according to the present invention, it is possible to provide a dielectric barrier discharge lamp having good spatial uniformity and temporal stability of light output and high luminous efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a dielectric barrier discharge lamp of the present invention.

FIG. 2 is an explanatory diagram of a mesh electrode.

FIG. 3 is an explanatory view of another embodiment of the dielectric barrier discharge lamp of the present invention.

FIG. 4 is an explanatory view of another embodiment of the dielectric barrier discharge lamp of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Discharge container 2 Inner tube 3 Outer tube 4 Net electrode 5 Aluminum vapor deposition film electrode 6 Getter 8 Power source 23 Elementary wire 24,25 Mesh 10a, 10b, 11a, 11b Electrode end 12a, 12b Stainless wire 13, 14a, 14b Silver paste 30a, 30b Folded portion of cylindrical net electrode 31a, 31b Nickel paste 41 Flat dielectric 43 Light transmissive net electrode 44a, 44b, 44c Internal electrode 45 Flat discharge container member 46 Quartz glass

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kunio Kasagi, 1194 Sado, Bessho-cho, Himeji-shi, Hyogo Ushio Denki Co., Ltd. (72) Inventor Yasuhiko Wakabata 1194 Sado, Bessho Town, Himeji City, Hyogo Prefecture Ushio Electric Co., Ltd.

Claims (6)

[Claims] 1. A discharge vessel is filled with a discharge gas that forms excimer molecules by a dielectric barrier discharge, and at least a part of the discharge vessel also serves as a dielectric of the dielectric barrier discharge. In a dielectric barrier discharge lamp, at least a part of which is transparent to light emitted from the excimer molecule, wherein at least a part of the dielectric is provided with a conductive thin film electrode or a conductive mesh electrode, A dielectric characterized in that the average thickness of the electrode end of the conductive thin film electrode or the conductive mesh electrode exceeds the average thickness of the conductive thin film electrode or the conductive mesh electrode. Barrier discharge lamp. 2. The discharge vessel has a substantially cylindrical outer shape,
The conductive thin film electrode or the conductive mesh electrode is provided outside the discharge vessel, and a wire, a metal stranded wire, a metal tape, or a metal mesh tape is attached to the electrode end of the conductive thin film electrode or the conductive mesh electrode. The dielectric barrier discharge lamp according to claim 1, wherein at least one selected from the above is wound. 3. An electrode on at least one member selected from the wire, the metal twisted wire, the metal tape, and the metal mesh tape wound around the electrode end of the conductive thin film electrode or the conductive mesh electrode. The dielectric barrier discharge lamp according to claim 2, wherein a lead wire is connected. 4. The discharge vessel has a substantially cylindrical outer shape,
The dielectric barrier discharge lamp according to any one of claims 1 to 3, wherein an end portion of the cylindrical net electrode is bent. 5. The dielectric barrier discharge lamp according to claim 3, wherein the conductive mesh electrode comprises a seamless cylindrical conductive mesh having elasticity in the axial direction. 6. The dielectric barrier discharge lamp according to claim 1, wherein a conductive paste is applied to an electrode end portion of the conductive thin film electrode or the conductive mesh electrode.