JPH10106507A - Ultraviolet ray lamp and its lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate effectively ultraviolet rays having a low wavelength range below 200nm. SOLUTION: An ultraviolet ray lamp and its lighting device include an ultraviolet ray transmissive air-tight vessel 5 which accommodates within a bottomed outer cylinder 2 a bottomed inner cylinder 3 smaller than the outer 2, wherein the open end of the space bounded by the outer and inner cylinders is sealed tightly so that the space serves as an electric discharge space 6, and further include an ultraviolet ray reflecting inside electrode 7 mounted on the inner surface of the inner cylinder, an outside electrode 8 mounted on at least part of the outer surface of the outer cylinder, and a discharge medium containing xenon encapsulated in the discharge space 6. A pulsated current with a high voltage (for example, 8kV) formed by superposing a high frequency (for example, 40kHz) on a direct current is impressed between the inside and outside electrodes, and thereby dielectric substance barrier discharging is generated between the two electrodes through the vessel 5 as an electric insulating member. Accordingly the number of linear discharges are generated in the discharge space 6 to cause energization of the xenon (Xe), and it is possible to generate a great quantity of ultraviolet rays in a low wavelength range, for example below 200nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet lamp for generating ultraviolet light by a dielectric barrier discharge for generating a discharge through a hermetic container made of glass or the like, which is an electrical insulator, and a lighting device therefor.

[0002]

2. Description of the Related Art Conventionally, as an example of this type of ultraviolet lamp, there is a lamp disclosed in Japanese Patent Publication No. Hei 8-21369. This is a method in which a pair of mesh electrodes are respectively attached to opposed outer surfaces of an ultraviolet-permeable glass bulb which is an airtight container enclosing a discharge medium mainly composed of xenon (Xe), and a high-frequency high voltage is applied between the pair of electrodes. Is applied to generate a discharge in the bulb.

[0003] This discharge is called a dielectric barrier discharge or a silent discharge performed through an electric insulator on the glass wall of the bulb, and a high-frequency pulse-like current flows.

Since this pulsed current has a high-speed electron flow and has many pauses, it excites a large amount of a substance that emits ultraviolet light such as Xe, and the excited substance is temporarily in a molecular state ( (Excimer state) and efficiently emits ultraviolet light with little reabsorption when returning to the ground state. The reason why the mesh electrode is used is to increase the electrode area and improve the stability of discharge. During stable discharge, light emission is observed near each intersection of the mesh.

[0005]

However, in such a conventional ultraviolet lamp, most of the emission wavelength of ultraviolet light from a rare gas is outside the vacuum system. There is a problem that the absorption of ultraviolet rays is extremely large and a large amount of water cannot be treated. The absorption in water is several micrometer with ultraviolet wavelength of 172nm.
m, several micro mm at 185 nm, 15-20 mm at 194 nm
In the conventional UV lamp, as shown in the spectrum diagram of the UV output light in FIG.
Low UV output of nm. For this reason, the conventional water treatment mainly uses ultraviolet rays of about 254 nm of the mercury emission line.

However, in ultrapure water for cleaning semiconductors,
Since the organic matter is not sufficiently decomposed only by the light cleaning treatment of ultraviolet light of 254 nm, ultraviolet light of 200 nm or less and practically transmitted to some extent in water is required, and an ultraviolet lamp for emitting the ultraviolet light is required. I have.

The present invention has been made in view of such circumstances, and has as its object to provide an ultraviolet lamp that efficiently generates ultraviolet light in a low wavelength range of 200 nm or less and a lighting device therefor. .

[0008]

According to the first aspect of the present invention, a bottomed outer cylinder is accommodated in a bottomed outer cylinder, and an opening in a space defined by the outer cylinder and the inner cylinder is provided. Seal the ends,
A hermetic container having an ultraviolet-transmitting property in which this space is formed in a discharge space portion; an inner electrode having an ultraviolet-reflecting property attached to the inner surface of the inner cylinder; and an outer electrode attached to at least a part of the outer surface of the outer cylinder And a discharge medium containing xenon sealed in the discharge space.

According to the present invention, a pulsating flow in which a high frequency (for example, 40 Kz) is superimposed on a direct current is applied at a high voltage (for example, 8 KV) between the inner and outer electrodes, so that an electrical insulator is provided between these two electrodes. A dielectric barrier discharge occurs via a certain hermetic container. For this reason, a large number of linear discharges are generated in the discharge space to excite xenon (Xe), for example, 20 μm.
A large amount of ultraviolet light in a low wavelength range of 0 nm or less can be generated.

Further, among the generated ultraviolet rays, those emitted toward the ultraviolet-reflective inner electrode are reflected by the inner electrode and radiated to the outside, so that the ultraviolet radiation efficiency can be improved.

In addition, since the outer surface of the airtight container, that is, almost the entire outer surface of the outer cylinder is a surface for emitting ultraviolet light, the amount of ultraviolet radiation can be increased. For this reason, by immersing the airtight container in water, a large amount of water can be subjected to light washing such as sterilization with ultraviolet rays in a low wavelength range, and a large amount of water treatment can be performed.

[0012] The invention of claim 2 is characterized in that at least a part of the airtight container and the outer electrode is immersed in water.

According to the present invention, since at least a part of the airtight container and the outer electrode are immersed in water, the immersed portion on the outer surface of the airtight container immersed in the water is set to substantially the same potential as the outer electrode via water. Can be set.

For this reason, the outer electrode is not formed on the entire outer surface of the hermetic container, but may be partially formed, so that the outer electrode can be saved and the portion through which the ultraviolet light passes through the outer electrode can be reduced. In addition, the amount of attenuation at the time of transmitting the ultraviolet rays can be reduced to further improve the radiation efficiency of the ultraviolet rays.

According to a third aspect of the present invention, the discharge medium contains xenon, mercury, and argon gas.

According to the present invention, since the mercury and the argon gas are sealed in the airtight container, the starting voltage can be reduced by the penning effect of the mercury and the argon gas. The invention according to claim 4 is characterized in that the outer electrode has ultraviolet transmittance.

According to the present invention, since the outer electrode has ultraviolet transmittance, it is possible to reduce the attenuation when the ultraviolet light generated in the hermetic container passes through the outer electrode, thereby increasing the amount of radiation to the outside. Can be.

A fifth aspect of the present invention is characterized in that a pulsating flow obtained by superimposing a high frequency on a direct current is applied to the inner and outer electrodes at a predetermined voltage.

According to the present invention, since a predetermined voltage of a pulsating current obtained by superimposing a high frequency on a direct current is applied to the inner and outer electrodes, even if the airtight container is an electric insulator such as glass, the high frequency of the pulsating current is applied. The component can cause a dielectric barrier discharge through the capacitance of the electrical insulator.

The invention according to claim 6 is characterized in that a potential distorted on the positive side of the pulsating flow is applied to the inner electrode, and a potential distorted on the negative side of the pulsating flow is applied to the outer electrode. I do.

According to the present invention, since the potential distorted to the positive side of the high-frequency pulsed pulsating flow is applied to the inner electrode, the mercury ions in the hermetic container are dissociated by the cataphoresis phenomenon into the outer electrode and the outer electrode. It can be unevenly distributed on almost the entire outer surface side of the airtight container having substantially the same potential.

For this reason, it is possible to suppress the reabsorption of the mercury ions due to the resonance transition, thereby increasing the amount of ultraviolet radiation of, for example, about 194 nm, and further increasing the amount of ultraviolet radiation radiated from the outer surface of the airtight container. Can be done.

According to a seventh aspect of the present invention, there is provided an ultraviolet lamp according to any one of the first to sixth aspects, and a lighting circuit for applying a pulsating flow obtained by superimposing a high frequency to a direct current to the inner and outer electrodes and stably lighting the same. It is characterized by having.

According to this invention, since the ultraviolet lamp according to any one of claims 1 to 6 is provided,
Functions and effects substantially similar to those of the present invention can be obtained.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described with reference to FIG. In these figures, the same or corresponding parts are denoted by the same reference characters.

FIG. 1 is a longitudinal sectional view of an ultraviolet lamp according to a first embodiment of the present invention. The ultraviolet lamp 1 is an ultraviolet lamp suitable for water treatment such as disinfection of water, and has a bottomed cylindrical outer cylinder 2 formed with quartz glass or the like so as to protrude axially outward in a dome shape. In addition, a bottomed cylindrical inner cylinder 3 made of quartz glass or the like having substantially the same shape but a small diameter and a small axis length is concentrically housed therein, and is defined by the upper ends of both the outer and inner cylinders 2, 3. At the annular opening end, an annular upper lid 4 is fixed and hermetically sealed, and the inner cylinder 3 is supported by the outer cylinder 2 to form a valve 5 which is an airtight container.

The valve 5 has, for example, an outer diameter of 30 mm and an inner diameter of 2 mm.
The discharge space 6 is 0 mm, and the planar shape defined by the inner peripheral surface of the outer cylinder 2 and the outer peripheral surface of the inner cylinder 3 forms an annular space in the discharge space portion 6. After evacuation, the discharge space 6 is filled with, for example, about 2.5 KPa of xenon (Xe) gas as a discharge medium, 3 KPa of argon gas, and an appropriate amount of mercury.

For example, a film-like inner electrode 7 is attached to almost the entire inner peripheral surface of the inner cylinder 3, while a film-like outer electrode 8 is attached to at least the outer surface of the dome-shaped bottom of the outer cylinder 2. And

The inner electrode 7 is formed and deposited by vapor deposition of aluminum or the like, and has a reflectivity for reflecting ultraviolet rays. On the other hand, the outer electrode 8 has a property of transmitting ultraviolet rays.

The inner and outer electrodes 7 and 8 have
A lighting circuit 11 such as an inverter is electrically connected by the lead wires 9 and 10 of the covered wire. As shown in FIG. 2, the lighting circuit 11 applies a high-frequency pulsed pulsating current 12 formed by superimposing a high frequency of 40 Kz on a DC component to the inner and outer electrodes 7 and 8 at about 8 KV. Is applied with a potential distorted to the positive side of the pulsating flow 12.

Therefore, the pulsating current 12 shown in FIG. 2 is supplied from the lighting circuit 9 to a predetermined voltage (about 40 KH) while the ultraviolet lamp 1 thus configured is immersed in water as shown in FIG.
When the voltage is applied to the inner and outer electrodes 7 and 8 at (z, 8 KV), the outer surface of the outer cylinder 2 that comes into contact with water has substantially the same potential as the outer electrode 8. Dielectric barrier discharge occurs through the glass walls of the outer and inner cylinders 2 and 3 which are electric insulators.

Therefore, a large number of linear discharges are generated along the radial direction in the discharge space 6 between substantially the entire outer surface of the outer cylinder 2 and between the outer electrode 8 and the inner electrode 7.

The ends of these linear discharges become spherically round near the inner surface of the glass wall of the inner cylinder 3 and discharge. The discharge moves around with time and spreads over the entire inner electrode 7 to live.
A pulsed high-frequency current flows.

This pulsed high-frequency current has a high-speed electron flow and excites xenon due to many pauses.
And when the excited substance temporarily binds to the molecular state (excimer state) and returns to the ground state, less reabsorption occurs.
For example, ultraviolet rays in a low wavelength range of 200 nm or less are emitted with high efficiency.

The ultraviolet rays pass through almost the entire outer surface of the outer cylinder 2 and the outer electrode 8 and are radiated radially into the surrounding water, so that a large amount of water treatment can be performed by a light washing action such as sterilization of water.

In addition, almost the entire outer surface of the outer cylinder 2 is an ultraviolet output surface, and the ultraviolet rays radiated toward the inner electrode 7 are reflected by the inner electrode 7 and radiated from the outer surface of the outer cylinder 2 into the surrounding water. Therefore, the amount of ultraviolet radiation can be increased.

Further, since a potential distorted to the positive side of the pulsating flow 12 is applied to the inner electrode 7, mercury ions are generated by the cataphoresis phenomenon in the vicinity of the outer electrode 7 and almost the entire inner surface of the outer cylinder 2 having substantially the same potential. It is unevenly distributed on the side.

[0038] For this reason, since the re-absorption that is often caused by the resonance transition is reduced, the ultraviolet light of about 194 nm is increased. According to the lighting experiment, if the potential on the inner electrode 7 side is distorted to the positive side by, for example, about 10% and the mercury ions are sufficiently localized toward the inner surface of the outer cylinder 2, the output may increase by about 7%. found.

FIG. 3 is a spectrum diagram of the ultraviolet output light of the ultraviolet lamp 1. In particular, the output of the ultraviolet light of 194.23 nm is greatly increased as compared with the spectrum diagram of the conventional ultraviolet output light shown in FIG. It indicates that In FIGS. 3 and 4, the vertical axis represents 1 for ultraviolet light of 184.97 nm.
The output of 94.23 nm ultraviolet light is relatively expressed.

In the above embodiment, the ultraviolet lamp 1
Has been described for use in water treatment, but the present invention is not limited to this.
Other liquids, spaces, and gas atmospheres may be used as long as they are effective with 4 nm ultraviolet irradiation. However, in a space or a gas atmosphere, it is natural that an appropriate electrode such as a metal mesh is required on almost the entire outer surface of the outer cylinder 2.

[0041]

As described above, the first aspect of the present invention is:
By applying a high voltage (for example, 8 KV) of a pulsating flow in which a high frequency (for example, 40 Kz) is superimposed on a direct current between the inner and outer electrodes, a dielectric barrier is provided between the two electrodes via an airtight container that is an electrical insulator. Discharge occurs. For this reason, a large number of linear discharges occur in the discharge space, and xenon (Xe)
To generate a large amount of ultraviolet rays in a low wavelength region of, for example, 200 nm or less.

Further, among the generated ultraviolet rays, those radiated toward the ultraviolet-reflective inner electrode are reflected by the inner electrode and radiated to the outside, so that the ultraviolet radiation efficiency can be improved.

Further, since the outer surface of the airtight container, that is, almost the entire outer surface of the outer cylinder is a surface for emitting ultraviolet light, the amount of ultraviolet radiation can be increased. For this reason, by immersing the airtight container in water, a large amount of water can be subjected to light washing such as sterilization with ultraviolet rays in a low wavelength range, and a large amount of water treatment can be performed.

According to the second aspect of the present invention, at least a part of the airtight container and the outer electrode are immersed in water, so that the immersed portion of the outer surface of the airtight container immersed in the water is substantially in contact with the outer electrode via water. The same potential can be set.

For this reason, the outer electrode is not formed on the entire outer surface of the hermetic container, but may be partially formed, so that the outer electrode can be saved and the portion through which the ultraviolet light passes through the outer electrode can be reduced. In addition, the amount of attenuation at the time of transmitting the ultraviolet rays can be reduced to further improve the radiation efficiency of the ultraviolet rays.

According to the third aspect of the present invention, since mercury and argon gas are sealed in the airtight container, the starting voltage can be reduced by the penning effect of mercury and argon gas.

According to the fourth aspect of the present invention, since the outer electrode has ultraviolet transmittance, the amount of ultraviolet light generated in the hermetic container when passing through the outer electrode is reduced to reduce the amount of radiation to the outside. Can be increased.

According to the fifth aspect of the present invention, since a predetermined voltage of a pulsating current obtained by superimposing a high frequency wave on a direct current is applied to the inner and outer electrodes, even if the airtight container is an electric insulator such as glass, the pulsating current is not applied. High frequency components of the flow can cause a dielectric barrier discharge through the capacitance of the electrical insulator.

According to the sixth aspect of the present invention, a potential distorted on the positive side of the high-frequency pulsed pulsating flow is applied to the inner electrode, so that the mercury ions in the hermetic container are separated from the outer electrode by the cataphoresis phenomenon. It can be unevenly distributed on almost the entire outer surface side of the airtight container having substantially the same potential as the outer electrode.

For this reason, it is possible to suppress the reabsorption of the mercury ions due to the resonance transition, thereby increasing the amount of ultraviolet radiation of, for example, about 194 nm, and further increasing the amount of ultraviolet radiation radiated from the outer surface of the airtight container. Can be done.

According to the seventh aspect of the present invention, since the ultraviolet lamp according to any one of the first to sixth aspects is provided, substantially the same operation and effect as those of the present invention can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an ultraviolet light and a lighting device thereof according to an embodiment of the present invention.

FIG. 2 is a waveform diagram of an applied voltage of a pulsating current applied to inner and outer electrodes from the lighting circuit shown in FIG. 1;

FIG. 3 is a spectrum diagram of ultraviolet output light of the ultraviolet lamp shown in FIG. 1;

FIG. 4 is a spectrum diagram of ultraviolet output light of a conventional ultraviolet lamp.

[Description of Signs] 1 Ultraviolet lamp 2 Outer tube 3 Inner tube 4 Top lid 5 Bulb (airtight container) 6 Discharge space 7 Inner electrode 8 Outer electrode 11 Lighting circuit 12 High-frequency pulsed pulsating flow

Claims (7)

[Claims] 1. A bottomed inner cylinder having a smaller size is accommodated in a bottomed outer cylinder, and the open end of a space defined by the outer cylinder and the inner cylinder is sealed. A hermetic container having ultraviolet permeability formed in a portion; an inner electrode having ultraviolet reflectivity attached to the inner surface of the inner cylinder; an outer electrode attached to at least a portion of the outer surface of the outer cylinder; A discharge medium containing xenon encapsulated in the ultraviolet lamp. 2. The apparatus according to claim 1, wherein at least a part of the airtight container and the outer electrode are immersed in water.
UV lamp as described. 3. The ultraviolet lamp according to claim 1, wherein the discharge medium contains xenon, mercury, and argon gas. 4. The ultraviolet lamp according to claim 1, wherein the outer electrode has ultraviolet transmittance. 5. The ultraviolet lamp according to claim 1, wherein a pulsating current obtained by superimposing a high frequency on a direct current is applied to the inner and outer electrodes at a predetermined voltage. 6. A structure according to claim 5, wherein a potential distorted on the positive side of the pulsating flow is applied to the inner electrode, and a potential distorted on the negative side of the pulsating flow is applied to the outer electrode. UV lamp. 7. An ultraviolet lamp according to any one of claims 1 to 6, and a lighting circuit for applying a pulsating current obtained by superimposing a high frequency to a direct current to inner and outer electrodes and stably lighting the same. A lighting device, characterized in that: