JP3630042B2 - Dielectric barrier discharge lamp - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a dielectric barrier discharge lamp.
[0002]
[Prior art]
The dielectric barrier discharge lamp of the present invention is described, for example, in JP-A-1-144560 or US Pat. No. 9,837,484, in which a discharge vessel is filled with a gas for forming excimer molecules, and a dielectric A radiator for extracting light emitted from excimer molecules by body barrier discharge, ie a dielectric barrier discharge lamp, is described. The dielectric barrier discharge lamp is also called “ozonizer discharge” or “silent discharge”, and is described in the revised edition “Discharge Handbook” published by the Institute of Electrical Engineers of Japan, June 1991, 7th edition, page 263.
[0003]
These documents describe that at least a part of the discharge vessel also serves as a dielectric for dielectric barrier discharge, and that the dielectric is light-transmitting and emits light from excimer molecules. The The dielectric barrier discharge lamp has characteristics that are not found in conventional low-pressure mercury lamps and high-pressure arc discharge lamps, for example, the center wavelength radiates vacuum ultraviolet rays having a short wavelength of 172 nm and has a single wavelength close to the line spectrum. Generating light selectively with high efficiency.
[0004]
FIG. 3 shows a specific example of such a conventional dielectric barrier discharge lamp. The discharge vessel 1 has a double tube structure in which an inner tube 2 and an outer tube 3 made of quartz glass are coaxially arranged, both ends of the inner tube 2 and the outer tube 3 are closed, and a discharge space 4 is interposed between them. Is formed. In the discharge space 4, for example, 40 kPa is charged as xenon gas as a discharge gas. Here, the inner tube 2 is provided with an inner electrode 5 which is a light reflecting plate and functions as an electrode for dielectric barrier discharge. This inner electrode is, for example, in the shape of a pipe made of aluminum. The outer tube 3 has both a function as a dielectric for dielectric barrier discharge and a function as a light extraction window, and an outer electrode 6 is provided on the outer surface. The outer electrode 6 is formed, for example, by inserting the discharge vessel 1 into a metal wire that is seamlessly knitted into a cylindrical shape, has a mesh shape, and can emit light from between the meshes. Therefore, the region where the outer electrode 6 is formed corresponds to a light transmissive portion. The inner electrode 5 is connected to the high voltage lead wire 12 through a lead wire. The outer electrode 6 is provided with a low voltage lead wire 13, and the high voltage lead wire 12 and the low voltage lead wire 13 are connected to a power source 14. The low voltage lead wire 13 is grounded as necessary. A projection 15 is formed in the inner tube 2 as a movement blocking member for the inner electrode 5. Further, at the end of the discharge vessel 1, there is a remaining exhaust pipe portion, that is, a so-called chip 16 that remains when the discharge vessel is molded. This chip 16 not only exhausts the residual gas from the inside of the discharge vessel 1 but also the remaining part of the exhaust pipe for filling the discharge gas, and when two cylindrical quartz glasses are coaxially arranged and joined. It may occur as a joint part.
[0005]
However, such a dielectric barrier discharge lamp has a problem in that cracks are generated from the chip 16 formed at the end of the discharge vessel while the lamp is turned on, and the discharge gas leaks or the discharge vessel itself breaks. . This cause is considered to be caused by the chip 16 becoming brittle because the vacuum ultraviolet light generated from the discharge space inside the discharge vessel directly irradiates the chip 16. Japanese Patent Application Laid-Open No. 9-97597 is for solving this problem, and prevents the chip from being directly irradiated with vacuum ultraviolet light generated from the discharge space.
[0006]
It has been found that the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 9-97597 solves the problem that the discharge gas leaks and the discharge vessel itself breaks, but it is still not fully solved.
This is because, as shown in FIG. 4, vacuum ultraviolet light that has not been radiated to the outside from the quartz glass forming the discharge vessel is guided by the fiber effect in the quartz glass, and ultraviolet distortion accumulates in a low-strength chip. It can be inferred that this will occur
[0007]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to provide a dielectric barrier discharge lamp in which ultraviolet distortion accumulates from a tip portion formed in a discharge vessel and does not cause discharge gas leakage or breakage of the discharge vessel itself.
[0008]
In order to solve the above-described problems, a dielectric barrier discharge lamp according to the present invention includes a discharge vessel made of quartz glass , an outer electrode arranged on the outer surface of the discharge vessel, and an outer surface of the discharge vessel or in a discharge space. A dielectric barrier discharge lamp in which a discharge gas for forming excimer molecules is filled by a dielectric barrier discharge by a pair of electrodes of an inner electrode exposed to the inner electrode, and a light transmissive portion is formed in at least a part of the discharge vessel. ,
The outer surface of the container at the end of the discharge container is coated with a frost process or a material different from the outer electrode and the inner electrode and having a refractive index higher than that of quartz glass.
[0009]
[Action]
With such a configuration, vacuum ultraviolet light generated from the discharge space inside the discharge vessel is formed on the outer surface at the end of the discharge vessel, even if the inside of the discharge vessel made of quartz glass is guided by the fiber effect. The vacuum ultraviolet light is emitted outside the discharge vessel by frost processing or high refractive coating. For this reason, the amount of ultraviolet light guided to the chip formed at the end of the discharge vessel is reduced or reduced without limit, and ultraviolet distortion is not accumulated in the chip.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a partially enlarged view of the end portion of the discharge vessel. In addition, the structure of the discharge lamp is the same as that shown in FIG. 3 except that a frost processing or a high refractive coating described later is applied.
As shown in FIG. 1, a frosted region 10 is formed around the chip 16 formed at the end of the discharge vessel 1. Frost processing is formed, for example, by applying irregularities of about 1 μm to 100 μm to quartz glass. The processing includes a generally known method such as sand blasting.
[0011]
By forming such a frosted region 10, vacuum ultraviolet light (ultraviolet light having a wavelength of 200 nm or less) transmitted by the fiber effect in the quartz glass of the discharge vessel 1 is satisfactorily obtained in the frosted region 10. It can be diverged outside the discharge vessel 1. Since there is no or very little vacuum ultraviolet light transmitted to the chip 16, the accumulation of ultraviolet distortion is eliminated, and the problems of discharge gas leakage and discharge vessel cracking are also eliminated.
The region to be frosted is not limited to the form shown in FIG. 1, but it is necessary to be around the chip where ultraviolet distortion accumulates. Further, a plurality of chips may be formed on the discharge vessel 1 as shown in FIG. In this case, it is preferable to provide frost processing around all the chips.
[0012]
Furthermore, in addition to the frost processing of the end portion of the discharge vessel 1, it is also possible to perform a high refractive coating. This high refractive coating is obtained by coating the outer surface of the discharge vessel 1 with, for example, alumina having a higher refractive index than quartz glass. Even with such a coating, the same operational effect as described above, that is, vacuum ultraviolet light (ultraviolet light having a wavelength of 200 nm or less) transmitted through the silica glass by the fiber effect can be diffused well outside the discharge vessel 1.
[0013]
The dielectric barrier discharge lamp of the present invention has a structure as shown in FIG. 3, that is, the inner tube 2 and the outer tube 3 are arranged coaxially, and ultraviolet rays are emitted from a mesh electrode disposed on the outer surface of the outer tube 3. It is not limited to the type that radiates.
For example, the structure shown in FIG. 2A, that is, the vacuum ultraviolet light 20 radiated from the discharge vessel is radiated from the direction perpendicular to the discharge direction by the inner electrode 5 and the outer electrode 6 to have a structure dielectric. It can also be applied to a barrier discharge lamp. Specifically, in FIG. 2A, ultraviolet light is emitted from the light transmission window 20.
Even in such a structure, the frost processing or the high refractive coating 10 can be provided around the chip 16.
Also, in the dielectric barrier discharge lamp having the structure in which the inner electrode 5 is exposed in the discharge space as shown in FIG. 2B, frost processing or high refractive coating can be applied to the periphery of the chip 16.
Furthermore, the present invention is not limited to the dielectric barrier discharge lamp having the above-described structure, and the present invention can be applied to various other forms of dielectric barrier discharge lamps.
[0014]
In the present invention, it has been explained that it is effective to apply a frost processing or a high refractive coating to the periphery of the chip. However, in addition to the chip, for example, by accumulating ultraviolet distortion such as a bonded portion of quartz glass constituting the discharge vessel. It is also effective to provide it in a portion where discharge gas leaks or the discharge vessel itself cracks. In addition, since the welding part of such a chip | tip or quartz glass is formed in the edge part of a discharge vessel, it is effective to carry out a frost process and a highly refractive coating to the said part.
[0015]
Thus, in the dielectric barrier discharge lamp of the present invention, the outer surface of the container at the end of the discharge container is frosted or highly refractory coated, so that the vacuum ultraviolet light generated from the discharge space inside the discharge container is quartz. Even if the inside of the discharge vessel made of glass is guided by the fiber effect, the vacuum ultraviolet light is diffused well outside the discharge vessel by the frost processing or the high refractive coating formed on the outer surface at the end of the discharge vessel. can do. For this reason, the amount of ultraviolet light guided to the chip formed at the end of the discharge vessel is reduced to no or infinitely less, and ultraviolet distortion is not accumulated in the chip.
[Brief description of the drawings]
FIG. 1 is a partially enlarged view for explaining a dielectric barrier discharge lamp of the present invention.
FIG. 2 is another embodiment of the dielectric barrier discharge lamp of the present invention.
FIG. 3 is a diagram showing a general structure of a dielectric barrier discharge lamp.
FIG. 4 is a diagram for explaining a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Discharge vessel 2 Inner tube 3 Outer tube 4 Discharge space 5 Inner electrode 6 Outer electrode 10 Frosted or highly refractive coated region 16 Tip

Claims (1)

Excimer molecules are formed by dielectric barrier discharge using a discharge vessel made of quartz glass and a pair of electrodes, the outer electrode placed on the outer surface of the discharge vessel and the inner electrode placed on the outer surface of the discharge vessel or exposed in the discharge space. In a dielectric barrier discharge lamp in which a discharge gas is filled and a light transmissive portion is formed in at least a part of the discharge vessel.
A dielectric body characterized in that the outer surface of the container at the end of the discharge container is coated with a frost process or a material different from the outer electrode and the inner electrode and having a higher refractive index than quartz glass. Barrier discharge lamp.

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