JP3178184B2 - 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 Electric Discharge Handbook, published by the Institute of Electrical Engineers of Japan, reprinted on June 7, 2001, page 263), and light emitted from the excimer molecules is extracted. A radiator, 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 a dielectric for the dielectric barrier discharge, and at least a portion of the dielectric A portion 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. Body barrier discharge lamp structure is described. The dielectric barrier discharge lamp as described above,
It is useful because it has various features not found in conventional low-pressure mercury discharge lamps and high-pressure arc discharge lamps. But,
Although the dielectric barrier discharge lamp as described above has a structure completely different from that of the conventional lamp, there has been a problem that a method for holding the lamp has not been sufficiently studied.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric barrier discharge lamp which has a sufficient light extraction efficiency and is easy to hold the lamp.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to fill at least a discharge vessel having a substantially cylindrical outer shape with a discharge gas for forming excimer molecules by a dielectric barrier discharge. At least a portion is light-transmissive to light emitted from the excimer molecule, and also serves as a dielectric of the dielectric barrier discharge, and at least a portion of the light-transmitting dielectric is electrically conductive. In a dielectric barrier discharge lamp provided with a reticulated electrode, it is attained by providing at least one end of the discharge vessel with a base having an outer diameter equal to or less than the outer diameter of the conductive reticulated electrode.
In addition, the object of the present invention is further achieved by configuring the base to have a vent for cooling the lamp.

[0005]

According to the present inventors, 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 an outer wall of the discharge vessel is formed of the excimer gas. A dielectric material that is light-transmissive to light emitted from molecules and serves also as a dielectric of the dielectric barrier discharge, and a conductive mesh electrode is provided on at least a part of the light-transmissive dielectric. The body barrier discharge lamp was examined in detail for light extraction efficiency. The light extraction efficiency was determined by the method of holding the dielectric barrier discharge lamp, and in particular, the base provided at the end of the dielectric barrier discharge lamp. Was found to be greatly influenced by the structure. That is, it has been found that when the outer diameter of the base exceeds the outer diameter of the conductive mesh electrode, the light extraction efficiency decreases.
Further, they have found that this is due to the light distribution unique to the cylindrical dielectric barrier discharge lamp. FIG. 2 is an explanatory diagram of a light distribution, in which the light distribution of a straight tube fluorescent lamp or a halogen lamp is in a direction perpendicular to the tube axis of the lamp.
That is, while the light output in the direction where θ is π / 2 is a circular curve 21 having a diameter, the light distribution of the dielectric barrier discharge lamp is smaller than the circular distribution when θ is around 0 and π. The distribution 22 has an increased light output. That is, in a dielectric barrier discharge lamp, the ratio of light emitted in a direction close to the tube axis is larger than that of a fluorescent lamp or the like. Therefore, the outer diameter of the base is smaller than the outer diameter of the conductive mesh electrode. If it exceeds, the light extraction efficiency decreases. That is, the fact that the light output, that is, the light extraction efficiency is reduced by the structure of the base is a phenomenon peculiar to the cylindrical dielectric barrier discharge lamp.

A discharge vessel having at least 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 outer wall of the discharge vessel emits light radiated from the excimer molecules. In a dielectric barrier discharge lamp, which is light-transmissive to and also serves as a dielectric of the dielectric barrier discharge, and a conductive mesh electrode is provided on at least a part of the light-transmissive dielectric,
Providing a base having an outer diameter equal to or less than the outer diameter of the conductive mesh electrode at at least one end of the discharge vessel, without first reducing the light extraction efficiency, second, thick, and
Compared to a case where the end of a coaxial cylinder having a complicated structure is directly supported, the position of the lamp can be easily and precisely set. The base in the present invention is a structure for the purpose of holding the lamp independent of the discharge vessel of the dielectric barrier discharge lamp, and is a structure fixed to the discharge vessel by bonding with an adhesive or the like or press fitting. Say. Further, the outer diameter of the conductive reticulated electrode in the present invention is the outer diameter of the reticulated electrode measured in a state of being mounted on the discharge vessel. For example, the outer diameter of the conductive mesh electrode when a cylindrical mesh in which a wire having a diameter of dmm intersects a discharge vessel having a diameter of Dmm is four times d and D due to the "overlap" of the wire.
The sum of

If the base has a structure having a vent for cooling the lamp, the lamp can be easily cooled, and a high-output dielectric barrier discharge lamp can be easily obtained. When the base is made of silicone rubber or fluororesin, the material has elasticity, and therefore, there is an advantage that the base is easily attached to the end of the discharge vessel and the lead wire connected to the electrode is easily taken out.

[0008]

1 is a schematic view of a coaxial cylindrical dielectric barrier discharge lamp according to an embodiment of the present invention. The discharge vessel 1 is made of quartz glass having a total length of about 150 mm, and has a hollow cylindrical shape in which an inner tube 2 having an outer diameter of 14 mm and an outer tube 3 having a thickness of 1 mm and 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, and a metal mesh electrode 4 that transmits light is provided on the outer surface. An aluminum electrode 5 also serving as a light reflecting plate is provided on the outer surface of the inner tube 2. Reference numeral 20 denotes a protective film made of an additional type silicon rubber provided for the purpose of mechanically and chemically protecting the aluminum electrode 5. A barium getter 6 is provided at one end of the discharge vessel 1. The mesh electrode 4 is a seamlessly knitted cylindrical net having elasticity in the axial direction, and the discharge vessel 1 is inserted into the cylindrical metal net.
Pulling in the axial direction of the lamp forms a reticulated electrode 5 close to the outside of the outer tube 3. Therefore, the outer diameter of the cylindrical mesh electrode is about 27.4 mm. Both ends of the discharge vessel are made of silicone rubber, have an outer diameter of 24 mm,
The ferrules 10 and 11 having the ventilation holes 12 and 13 were mounted using a silicone rubber-based adhesive. The adhesive is not shown.

Xenon gas as a discharge gas was sealed at 300 Torr in the discharge space 7 of the discharge vessel. When discharge was performed at a power of 2 watts per 1 cm of lamp length using a power supply 8 having a frequency of 20 kHz, ultraviolet light at 172 nm and its vicinity was emitted with high efficiency. Since the base has an outer diameter less than the outer diameter of the conductive mesh electrode, without directly lowering the light extraction efficiency, and further directly supporting the end of a coaxial cylinder having a thick and complicated structure. The position of the lamp could be easily and precisely set as compared with the above. Also, by flowing nitrogen gas through the vent holes provided in the base to cool the lamp, a high-output dielectric barrier discharge lamp was obtained in which the efficiency did not decrease even when the lamp was turned on with three times the electric input. . Further, since the base is made of silicone rubber, it has elasticity, so that it can be easily mounted on the discharge vessel.
There is an advantage such as having a sufficient lifetime since the film has a sufficient resistance to ultraviolet light in the vicinity of nm and its vicinity.

The same effect as in the above embodiment was obtained by using a fluorine resin base instead of the silicone rubber. Also, it is obvious that the use of a ceramic or metal base does not reduce the light extraction efficiency and can easily and precisely set the position of the lamp. .

[0011]

As described above, according to the present invention, it is possible to provide a dielectric barrier discharge lamp having sufficient light extraction efficiency and easy holding of the lamp.

[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 light distribution.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge container 2 Inner tube 3 Outer tube 4 Cylindrical mesh electrode 5 Aluminum electrode 6 Getter 8 Power supply 10,11 Base 12,13 Vent hole

──────────────────────────────────────────────────続 き Continuing from the front page Examiner Katsumi Enari (56) References JP-A-2-7353 (JP, A) JP-A-4-137640 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 61/04 G21K 5/00

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 an outer wall of the discharge vessel comprises:
Light transmissive to light emitted from the excimer molecule, and also serves as a dielectric of the dielectric barrier discharge;
In a dielectric barrier discharge lamp in which a conductive mesh electrode is provided on at least a part of the light-transmitting dielectric, a cap having an outer diameter equal to or less than the outer diameter of the conductive mesh electrode is provided on at least one end of the discharge vessel. A dielectric barrier discharge lamp. 2. The dielectric barrier discharge lamp according to claim 1, wherein the base has a vent for cooling the lamp. 3. The dielectric barrier discharge lamp according to claim 1, wherein said base is made of silicone rubber or fluorine resin.