JP2775697B2 - 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 Laid-Open Publication No. 2-7353, in which a discharge vessel is filled with a discharge gas for forming excimer molecules, and a dielectric material is filled. Excimer molecules are formed by barrier discharge (also known as ozonizer discharge or 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 extracted. A radiator, i.e. a dielectric barrier discharge lamp, is described wherein the discharge vessel of the lamp is cylindrical and at least a part of the discharge vessel also serves as a dielectric for the dielectric barrier discharge, 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. Is the dielectric barrier discharge lamp structure 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, since the discharge vessel is cylindrical, a flat mesh
When the electrode is wound around the surface of the discharge vessel,
There are many parts that overlap and overlap.
U. Because of this, the spatial uniformity of light output and the temporal
Stability is not always sufficient, and the luminous efficiency
There was a problem that it was not enough.

[0003]

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

[0004]

Means for Solving the Problems The object of the present invention is to
A discharge vessel having a substantially cylindrical outer shape is filled with a discharge gas for forming excimer molecules by dielectric barrier discharge,
At least a part of the discharge vessel is a dielectric for performing a dielectric barrier discharge, and at least a part of the dielectric is light-transmissive to light emitted from the excimer molecule, and In a dielectric barrier discharge lamp in which a reticulated electrode is provided on at least a part of the light transmitting portion, the reticulated electrode has a cylindrical seam having elasticity in an axial direction.
It is achieved by configuring with less . Further, the object of the present invention can be further achieved by forming the reticulated electrode by a single metal wire, or by forming the reticulated electrode by coating a conductive material on a net made of an organic material. .

[0005]

[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 have studied the stability of light output, that is, the temporal fluctuation of light output, in a dielectric barrier discharge lamp having a structure in which a conductive mesh electrode is provided on a substantially cylindrical light-transmitting dielectric which is a light extraction window member. , Spatial uniformity, and luminous efficiency are affected by the small gap created between the conductive mesh electrode and the light-transmitting dielectric, and furthermore, by the uniformity of the conductive mesh electrode. Experimentally discovered that That is, in a dielectric barrier discharge lamp having a cylindrical outer shape, if the cylindrical light-transmitting dielectric and the conductive reticulated electrode are to be completely brought into close contact with each other, the edges of the net are overlapped. Due to the fixed position, perfect adhesion is difficult, and thus a gap may be formed between the light-transmitting dielectric and a portion of the conductive mesh electrode along the edge. Then, an extra discharge is generated in the minute gap. As a result, this extra discharge generates harmful compounds around the lamp. For example, when the atmosphere is air, nitrogen oxides and ozone are generated, and the discharge becomes unstable and the light output is reduced. It has been found that problems such as instability and reduced luminous efficiency occur. Further, even when the cylindrical light-transmitting dielectric and the conductive reticulated electrode are completely adhered over the whole, when the conductive reticulated electrode is non-uniform,
For example, in a state where the edges of the conductive mesh electrode overlap and overlap on a part of the cylindrical light-transmitting dielectric, a spatially non-uniform discharge occurs and the light output Have been found to be spatially non-uniform, and the light output has become unstable due to the unstable discharge.

A discharge vessel having at least a substantially cylindrical outer shape is filled with a discharge gas for forming 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. A dielectric barrier discharge in which at least a part of the dielectric is light transmissive to light emitted from the excimer molecule, and at least a part of the light transmissive dielectric is provided with a conductive mesh electrode. In a lamp, the conductive mesh electrode is formed by connecting a cylindrical conductive mesh having elasticity in an axial direction , for example, a seamless (seamle).
ss), when a substantially cylindrical discharge vessel is inserted into the cylindrical conductive net, and then the cylindrical conductive net is pulled in the axial direction, the radius of the conductive mesh electrode shrinks. Since the light-transmitting dielectric and the conductive reticulated electrode, which are substantially cylindrical, are completely adhered to each other, there is no void in a part thereof. As a result, no extra discharge occurs, and As a result, no harmful compounds are generated around the lamp, the discharge is stabilized, the light output is stabilized, and the luminous efficiency is increased. Furthermore, there is no doubled part where edges overlap and differ from the conventional conductive mesh electrode, that is, the cylindrical conductive mesh electrode of the present invention.
The poles are substantially uniform on the surface of the light-transmitting dielectric, which is substantially cylindrical, and as a result, a spatially uniform discharge occurs, the discharge is stabilized, and the light output is stable. Can be obtained.

[0007] At both ends in the axial direction of the cylindrical conductive net, there are cut ends of the conductive wires forming the net. The cut end of the conductive element wire has a needle-like shape. Therefore, in the vicinity of the cut end, the electric field becomes strong and the discharge is often concentrated. If the cylindrical conductive net is constituted by one metal wire, only one cut end of the metal wire is present at each axial end of the cylindrical conductive net. By easily processing the end, for example, bending the cut end toward the net, it is possible to prevent the generation of a strong electric field, and thus to obtain a dielectric barrier discharge lamp with stable discharge. Further, the cylindrical conductive net is a net made of an organic substance, for example, a net made of a nylon fiber is a conductive substance,
For example, when the structure is coated with silver, there is an advantage that the elasticity of the conductive mesh electrode is improved and the conductive mesh electrode is easily attached.

[0008]

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 300 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. Outer tube 3 and inner tube 2
Is used also as a dielectric barrier for the dielectric barrier discharge and a light extraction window member, and metal mesh electrodes 4 and 5 that transmit light are provided on the outer surface. A barium getter 6 is provided at one end of the discharge vessel 1. Further, the getter 6 is merely prevented from moving into the discharge space by the protrusion 9 provided on the outer tube 3, and the
Not fixed.

As shown in FIG. 2, the reticulated electrodes 4 and 5 are formed by a single metal wire 23 in the circumferential direction 22a of the cylinder.
22b is a seamless cylindrical net having a structure in which loops are repeatedly formed, the metal wire is a Monel having a diameter of 0.1 mm, and the area of each of the large mesh 24 and the small mesh 25 is about 2
And 1 square millimeter. FIG. 3 is a perspective view of the mesh electrode. 100 and 101 are ends of the strand. The discharge vessel 1 is inserted into the cylindrical metal net, and is pulled in the axial direction (20a, 20b) of the lamp so that the outer tube 3
A mesh electrode 5 is formed in close contact with the inside of the inner tube 2 by inserting the cylindrical metal mesh into the inner tube 2 and compressing the cylindrical metal mesh in the axial direction of the lamp. A reticulated electrode 4 was formed. That is, according to the above configuration of the present invention, each electrode is connected to the outer tube 3 and the inner tube 2.
Without any gaps. Xenon gas was sealed in the discharge space 7 as a discharge gas at 300 Torr. When discharge is performed at a power of 8 watts per 1 cm of lamp length with a power supply 8 having a frequency of 15 kHz, extra discharge may occur between the outer tube 3 and the electrode 5 and between the inner tube 2 and the electrode 4. Therefore, the generation of harmful compounds around the lamp can be prevented, and the discharge becomes stable,
Ultraviolet rays at and around 72 nm were radiated with high efficiency, and the luminous efficiency was improved by about 10%.

Further, when a conventional flat or tape-shaped metal net is wound around a discharge vessel and its edge is sewn or fixed in an overlapping manner, the metal net is formed at the joining portion of the metal net. , Or a gap occurs between the metal meshes, resulting in spatial nonuniformity of the metal mesh electrodes. However, as in the present invention, the mesh electrode is connected to the discharge vessel in the axial direction.
As a result of the cylindrical conductive member having elasticity, no spatial non-uniformity occurs on the surface of the dielectric which also serves as a light extraction window member of the metal mesh electrode, and a spatially uniform discharge occurs, A stable discharge was obtained. Further, since the cylindrical metal net is made of a single metal wire, only one cut end of the metal is present at each axial end of the cylindrical conductive net. The cut end could be easily treated, for example, by bending the cut end of the wire onto the metal net, and thus a stable discharge could be obtained. The book
The reticulated electrode in the invention has elasticity in the axial direction of the discharge vessel.
In particular, if it is a cylindrical conductive net,
There is no, but it is most effective to construct
It has excellent adhesion to the discharge vessel,
Good uniformity and temporal stability.

In the second embodiment of the present invention, the electrode 4 in the first embodiment is a metal thin film electrode also serving as a light reflection plate on which aluminum is deposited, and the electrode 5 is formed of a mesh made of knitted nylon fibers. Silver was deposited. Also in the present embodiment, the occurrence of extra discharge between the outer tube 3 and the electrode 5 is reduced, so that the generation of harmful compounds around the lamp is reduced, and a spatially uniform discharge is generated. 172 nm
And the ultraviolet rays in the vicinity thereof were emitted with high efficiency, and the luminous efficiency was improved. Further, the mesh electrode of this embodiment has a large elasticity, and has an advantage that the electrode can be easily installed.

[0012]

As described above, according to the present invention, it is possible to provide a cylindrical 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 a perspective view of a mesh electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge container 2 Inner tube 3 Outer tube 4,5 Reticulated electrode 6 Getter 7 Discharge space 8 Power supply 23 Element wire 24,25 mesh

 ──────────────────────────────────────────────────続 き Continuation of the front page Examiner Yoshiyuki Shimonaka (56) References JP-A-2-7353 (JP, A)

Claims (3)

(57) [Claims] 1. A discharge vessel having a substantially cylindrical outer shape is filled with a discharge gas for forming excimer molecules by a dielectric barrier discharge, and at least a part of the discharge vessel is a dielectric for performing a dielectric barrier discharge. Wherein at least a part of the dielectric is light-transmissive to light emitted from the excimer molecule, and a reticulated electrode is provided on at least a part of the light-transmitting part. in the barrier discharge lamp, the mesh electrode includes a cylindrical sea having elasticity in the axial direction
A dielectric-barrier discharge lamp characterized by being made of stainless steel . 2. The dielectric barrier discharge lamp according to claim 1, wherein the mesh electrode is formed of a single metal wire. 3. The dielectric barrier discharge lamp according to claim 1, wherein the mesh electrode is formed by coating a conductive material on a mesh made of an organic material.