JP2836056B2 - Dielectric barrier discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a kind of discharge lamp used as, for example, an ultraviolet light source for a photochemical reaction, in which excimer molecules are formed by dielectric barrier discharge and light emitted from the excimer molecules is used. 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 Patent Application Laid-Open Publication No. Hei 2-7353, in which at least a discharge vessel is filled with a discharge gas for forming excimer molecules, and a dielectric gas is charged. Excimer molecules are formed by a body barrier discharge (also known as an ozonizer discharge or a silent discharge. See the revised edition of the “Discharge Handbook” published by the Institute of Electrical Engineers of Japan, reprinted in June 2001, page 263), and the light emitted from the excimer molecules is emitted. An extractor, i.e., a dielectric barrier discharge lamp, is described wherein the discharge vessel is cylindrical, at least a portion of the discharge vessel also serves as the dielectric for the dielectric barrier discharge, and At least a portion is light-transmissive to light emitted from the excimer molecule, and a conductive mesh electrode is provided on at least a portion 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 not found in conventional low-pressure mercury discharge lamps and high-pressure arc discharge lamps. However, the dielectric barrier discharge lamp as described above,
There is a problem that spatial uniformity and temporal stability of light output are not always sufficient, and 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 of light output and good temporal stability and high luminous efficiency. It is.

[0004]

An object of the present invention is to at least fill a discharge vessel with a discharge gas for forming excimer molecules by dielectric barrier discharge, wherein at least a part of the discharge vessel is filled with the dielectric barrier discharge. At least a part of the discharge vessel is light-transmissive to light emitted from the excimer molecule, and at least a part of the dielectric is a conductive thin-film electrode or a conductive mesh electrode. In the dielectric barrier discharge lamp provided with, the thickness of the electrode end of the conductive thin-film electrode or the conductive mesh electrode,
This is achieved by configuring the conductive thin film electrode or the conductive mesh 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 mesh electrode is provided outside the discharge vessel, and the conductive thin film electrode or the conductive mesh electrode is provided at an electrode end of the conductive mesh electrode. A structure in which at least one selected from wire, metal stranded wire, metal tape, and metal mesh tape is wound; and further, the cylinder formed of a seamless cylindrical conductive net having elasticity in the axial direction. The object of the present invention can be further achieved by bending the end portion of the mesh electrode.

Further, an electrode lead wire is connected to at least one member selected from the group consisting of the wire wound around the end of the cylindrical conductive net, a metal stranded wire, a metal tape and a metal net tape. Alternatively, the object of the present invention can be further achieved by adopting a configuration in which a conductive paste is applied 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), a large number of minute discharge plasmas (hereinafter referred to as microplasmas) having a very small plasma diameter and a very short discharge duration. We fill at least a discharge vessel with a discharge gas for forming excimer molecules by a dielectric barrier discharge, at least a part of the discharge vessel also serves as a dielectric of the dielectric barrier discharge, and at least a part of the discharge vessel. Some are light-transmissive to light emitted from the excimer molecules, 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, the Output stability, spatial uniformity, and luminous efficiency are affected by the end of the conductive thin-film electrode or conductive mesh electrode provided on the dielectric,
Further, by configuring the thickness of the end portion of the conductive thin-film electrode or the conductive mesh electrode to exceed the average thickness of the conductive thin-film electrode or the conductive mesh electrode, it is possible to solve the above-described problem. Discovered experimentally.

The mechanism for improving the temporal stability, spatial uniformity, and luminous efficiency of the light output is not necessarily clear, but is considered as follows. That is, the conductive thin-film electrode or the conductive reticulated electrode is thin in the first place, and the terminal portion thereof tends to be a knife blade or a needle, so that the electric field intensity is nonuniform and large at the end portion. Therefore, at the end of the conductive thin-film electrode or the conductive mesh electrode, a discharge in the form of a creeping discharge occurs in an atmosphere gas such as air instead of a discharge gas, and microplasma concentrates at the end of the electrode. Many occur. As a result, the discharge becomes unstable, and the light output at the end of the electrode increases, that is, the temporal fluctuation of the light output increases, and the spatial uniformity of the light output deteriorates. In addition, when a creeping discharge is generated in an atmosphere gas such as air, or when microplasma is excessively concentrated, the luminous efficiency is reduced.

At least the discharge vessel is filled with a discharge gas for forming excimer molecules by dielectric barrier discharge,
At least a part of the discharge vessel also serves as a dielectric of the dielectric barrier discharge, and at least a part of the discharge vessel is light-transmissive to light emitted from the excimer molecule,
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 determined by the conductive thickness. If it is configured to exceed the average thickness of the conductive thin-film electrode or conductive mesh electrode,
The concentration of the electric field intensity at the end of the electrode is reduced, so that the electric field intensity is relatively uniform and the intensity is weakened. As a result, spatial uniformity of light output, temporal fluctuation of light output, and luminous efficiency are improved. The term “electrode end” in the present invention refers to an electrode portion that is equal to or shorter than the discharge gap length of the dielectric barrier discharge from the electrode terminal end, that is, 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, and the conductive thin film electrode or the conductive mesh electrode is provided outside the discharge vessel, and the electrode end of the conductive thin film electrode or the conductive mesh electrode is provided. Wire, metal stranded wire, metal tape,
With a configuration in which at least one selected from metal mesh tape is wound, or by bending the end of the cylindrical mesh electrode, the thickness of the end of the electrode can be uniformly increased with a simple operation. It becomes possible. Further, an electrode lead wire is attached to at least one member selected from the wire, metal stranded wire, metal tape, and metal mesh tape wound around the electrode end of the conductive thin film electrode or the conductive mesh electrode. When connected, the connection of the conductive thin-film electrode or the conductive reticulated electrode is reliably performed with high mechanical strength, so that a highly reliable dielectric barrier discharge lamp can be obtained.

When the conductive mesh electrode is constituted by a seamless cylindrical conductive mesh having elasticity in the axial direction, a generally cylindrical discharge vessel is inserted into the cylindrical conductive mesh, and then the cylinder is inserted into the cylindrical conductive mesh. When the conductive mesh is pulled in the axial direction, the radius of the conductive mesh electrode shrinks and the light-transmitting dielectric, which is substantially cylindrical, and the conductive mesh electrode are completely adhered to each other, so that a gap is partially generated. As a result, no extra discharge is generated, and no harmful compounds are generated around the lamp due to the extra discharge, and the discharge becomes stable and the light output becomes stable, Further, the luminous efficiency increases. That is, the conductive mesh electrode does not overlap with the conductive mesh electrode by forming the suture line portion by rolling the flat mesh electrode, and the conductive mesh electrode is formed of the light-transmitting dielectric that is substantially cylindrical. The dielectric barrier discharge lamp is sufficiently uniform on the surface, as a result, a spatially uniform discharge is generated, the discharge is stabilized, and the light output is stable.

When a conductive paste containing silver, gold, nickel, carbon or the like as a main component is applied to the electrode end 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 thus the uniformity of the electric field strength can be further improved. When a conductive paste is applied to a portion where an electrode lead wire is connected to at least one member selected from the wire, metal stranded wire, metal tape, and metal mesh tape wound around the electrode end, the conductive Since the connection of the thin-film electrode or the conductive mesh electrode is reliably performed with higher mechanical strength, a highly reliable dielectric barrier discharge lamp can be obtained.

[0012]

FIG. 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 a hollow cylindrical shape 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. The outer tube 3 also serves as a dielectric barrier for the 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 serving also as a light reflecting 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.

As shown in FIG. 2, the reticulated electrode 4 is formed by seamlessly knitting a single metal wire 23 in a cylindrical shape, and loops are repeatedly formed in the circumferential direction 22a, 22b of the cylinder. A cylindrical mesh with a metal wire diameter of 0.1 mm
The area of the large mesh 24 and the small mesh 25 is about 2 and 1 square millimeter, respectively.
The discharge vessel 1 was inserted into the cylindrical metal net, and was pulled in the axial direction of the lamp to form a mesh electrode 4 which was in close contact with the outer tube 3. That is, according to the above configuration of the present invention, each cylindrical mesh electrode 4 is
Without any gaps. 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 mesh electrode 4 over a length of 3 mm in the axial direction of the lamp. The electrode lead wire 9 was connected to the stainless wire 12a, and a silver paste 13 was applied thereon with a thickness of about 0.5 mm. The electrode ends 10a and 10b of the inner electrode 5 are coated with silver pastes 14a and 14b of about 0.5 mm in thickness and 5 mm in length.
mm. Xenon gas as a discharge gas was filled in the discharge gap 7 of the discharge vessel at 300 Torr. When discharge was performed with a power of 8 watts per 1 cm of lamp length using a power supply 8 having a frequency of 20 kHz, a dielectric barrier discharge lamp having improved spatial uniformity of light output, temporal fluctuation of light output, and luminous efficiency was obtained. Obtained.

FIG. 3 is a schematic diagram showing a coaxial cylindrical dielectric barrier discharge lamp according to a second embodiment of the present invention. Except for the structure of the electrode ends 11a and 11b of the cylindrical mesh electrode 4, the structure is the same as that of the first embodiment. The electrode ends of the cylindrical mesh 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 with improved spatial uniformity of light output, temporal fluctuation of light output and luminous efficiency was obtained.

FIG. 4 is a schematic diagram of a disk-shaped dielectric barrier discharge lamp according to a third embodiment of the present invention. 100m diameter
a flat dielectric member 41 made of a synthetic quartz glass plate having a thickness of 1.5 mm and a thickness of 1.5 mm;
5 and a cylindrical quartz glass 46 form a disk-shaped discharge vessel 49. The plate-shaped dielectric 41 also serves as a dielectric barrier discharge dielectric and a light extraction window member, and a stainless steel wire having a diameter of 0.1 mm is formed on its outer surface by 2 mm.
A metal mesh electrode 43 having a diameter of 80 mm and a structure 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 mounted on the flat discharge vessel member 45 coaxially with the electrode 44a. 44b and 44c. The electrodes 44a, 44b, 44c also serve as reinforcing members for the plate-like dielectric 1 against atmospheric pressure. Electrode 4
4a, 44b, and 44c are only in contact with the plate-shaped dielectric 41 and are not mechanically fixed to the plate-shaped dielectric 41. Electrodes 44a, 44b, the portions facing the discharge space 44c and the flat plate-like discharge container member 45 and covered with a dielectric 40 made of MgF _2. Electrode end 48 of metal mesh electrode 43
A stainless steel 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 plate-shaped dielectric 41 using a silicone rubber-based adhesive 51.

A xenon gas of 350 Torr is filled in the space 47 as a discharge gas, and the electrode 43 and the electrodes 44a and 44a are filled.
When an AC voltage is applied by the power supply 8 between the electrodes 4b and 44c, creeping discharge plasma 52 is generated in the vicinity of the plate-like dielectric 41, and the ultraviolet light having a maximum value at a wavelength of 172 nm and its vicinity from the excimer molecule of xenon is efficiently emitted. 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 of light output and good temporal stability and high luminous efficiency.

[Brief description of the 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 Mesh electrode 5 Aluminum vapor deposition film electrode 6 Getter 8 Power supply 23 Element wire 24, 25 Mesh 10a, 10b, 11a, 11b Electrode end 12a, 12b Stainless steel wire 13, 14a, 14b Silver paste 30a, 30b Folded portion of cylindrical mesh electrode 31a, 31b Nickel paste 41 Flat dielectric 43 Light transmissive mesh electrode 44a, 44b, 44c Internal electrode 45 Flat discharge vessel member 46 Quartz glass

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Asahina 1194, Sado Bessho-cho, Himeji-shi, Hyogo Ushio Electric Co., Ltd. Examiner in a corporation Hiroshi Kojima (56) References JP-A-5-174792 (JP, A) JP-A-2-7353 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01J 65/00

Claims (2)

(57) [Claims] A discharge vessel is filled with a discharge gas for forming excimer molecules by a dielectric barrier discharge, and at least a part of the discharge vessel also serves as a dielectric for the dielectric barrier discharge. At least a part is light-transmissive to light emitted from the excimer molecule, and 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, A dielectric material characterized in that the average thickness of the electrode ends 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, a metal mesh tape is provided at an electrode end of the conductive thin film electrode or the conductive mesh electrode. 2. The dielectric barrier discharge lamp according to claim 1, wherein at least one selected from the group is wound.