JP3102430B2 - 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. 2-7353. 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 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 structure 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 above-described dielectric barrier discharge lamp has a problem that the luminous efficiency is not always sufficient.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric barrier discharge lamp having a stable discharge and high luminous efficiency.

[0004]

The object of the present invention is to fill a discharge vessel with a discharge gas for forming excimer molecules by a dielectric barrier discharge, wherein at least a part of the discharge vessel is filled with the dielectric barrier discharge. The dielectric barrier discharge lamp, which also functions as a dielectric and is light-transmissive to light emitted from the excimer molecule, and at least a part of the light-transmissive portion is provided with one electrode. Is made of a perforated metal plate.

[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 investigated the stability of light output, that is, the temporal fluctuation of light output, and the luminous efficiency of a dielectric barrier discharge lamp in which a conductive mesh electrode is provided on a light-transmitting dielectric, which is a light extraction window member. Has experimentally found that it is affected by the small voids created between the conductive mesh electrode and the light transmissive dielectric. That is, it is difficult to completely adhere the light-transmitting dielectric and the conductive reticulated electrode over the whole, and therefore, a gap is generated between the light-transmitting dielectric and a part of the conductive reticulated electrode. Sometimes. 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.

Accordingly, the present invention provides a discharge vessel filled 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 for the dielectric barrier discharge. In a dielectric barrier discharge lamp in which one electrode is provided in at least a part of the light-transmitting portion, the electrode is formed of a perforated metal plate. Therefore, it has the following features. That is, all the parts constituting the electrode are located on the same plane. In particular, even at the intersections between the electrode portions of the metal plate having a width, the intersections are on the same plane, and no gap is formed between the dielectric material and the electrodes in this portion. As a result, unnecessary discharge does not occur, and the object of the present invention can be achieved.

[0007]

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 also used as a dielectric barrier of the dielectric barrier discharge and a light extraction window member, and has electrodes 4 and 5 transmitting light on its outer surface.
Is provided. The electrode 4 has a structure in which one metal plate is perforated as shown in FIG. 2, and the metal plate is made of aluminum having a thickness of 0.2 mm, and a diamond-shaped hole, that is, a mesh 21 is perforated. The remaining metal plate portions 22a, 22b, 22c,... Having a width of 0.2 mm and 23a, 23
, 23c,... cross each other diagonally.

Further, in the case of the structure in which the thin metal wires shown in the conventional example are knitted, since one thin metal wire is located on the other thin metal wire at a portion where the thin metal wires intersect with each other, it is difficult to connect the thin metal wire to the light-transmitting dielectric. In contrast to the case where a gap is generated between the conductive electrodes and a structure in which the conductive electrode is perforated in one metal plate as in the present invention, the wires constituting the electrodes are in the same plane even at the intersection thereof. Therefore, a gap is not further generated between the light transmitting dielectric and a part of the conductive electrode, and as a result, no extra discharge is generated.

Returning to the description of FIG. 1, a barium getter 6 is provided at one end of the discharge vessel 1. Getter 6
Are merely prevented from moving into the discharge space by the projections 9 provided on the outer tube 3 and are not fixed to the discharge vessel 1. Xenon gas was sealed in the discharge space 7 as a discharge gas at 300 Torr. When discharge was performed at a power of 8 watts per 1 cm of a lamp using a power supply 8 having a frequency of 20 kHz, the space between the outer tube 3 and the electrode 5 and the inner tube 2
No extra discharge is generated between the electrode and the electrode 4. Therefore, generation of harmful compounds around the lamp can be prevented, and the discharge becomes stable, and ultraviolet rays at 172 nm and its vicinity are radiated with high efficiency. As a result, the luminous efficiency was improved by about 10%. Further, the electrode 4 provided on the outer surface of the inner tube 2 does not need to be a perforated metal plate, and may be a metal thin film electrode also serving as a light reflecting plate on which aluminum is deposited.

[0010]

As described above, according to the present invention, a highly efficient dielectric barrier discharge lamp can be provided.

[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 a diagram illustrating an example of an electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge container 2 Inner tube 3 Outer tube 4, 5 Electrode 7 Discharge space 8 Power supply

────────────────────────────────────────────────── ─── Continuing from the front page Examiner Shinichi Omori (56) References JP-A-5-266863 (JP, A) JP-A-63-229777 (JP, A) JP-A-4-223039 (JP, A) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 65/00 H01J 65/04

Claims (1)

(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 of the dielectric barrier discharge and emits from the excimer molecules. A dielectric barrier discharge lamp provided with one electrode on at least a part of the light transmitting portion, wherein the electrode is formed of a perforated metal plate. Dielectric barrier discharge lamp.