JP2001283785A - Dielectric barrier discharge lamp and its apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the flicker of light emission SOLUTION: The dielectric barrier discharge lamp comprises a tubular airtight receptacle 1 made of ultraviolet transmitting material including excimer generating gas inside, an internal electrode 2 having spirals along the inner surface of the airtight receptacle 1 and an external electrode 4 placed on the outer surface of the airtight receptacle 1. This layout contributes to shorten the distance between the internal electrode 2 and the external electrode 4. As a result, the discharge distribution of the internal electrode 2 in axial direction is uniformed to maintain the uniform light emission free from flicker.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric barrier discharge lamp and a dielectric barrier discharge lamp device using the same.

[0002]

2. Description of the Related Art An excimer discharge lamp that emits a near-monochromatic radiation by causing an electrodeless discharge of a rare gas such as xenon or a mixed gas such as a rare gas such as xenon or krypton and chlorine is disclosed in, for example, Gellert and U. Kogelschatz “Generation of Exci
mer Emission in Dielectric Barrier Discharges ”Ap
plied Physics B 52, 14-21-Japanese Patent Application Laid-Open No. Hei 6-310104-Japanese Patent Application Laid-Open No. 7-272692-Japanese Patent Application Laid-Open No. Hei 7-220687, etc.

FIG. 7 is a front view illustrating a conventional dielectric barrier discharge lamp.

In FIG. 7, 101 is a cylindrical airtight container, 102 is an external electrode having conductivity, 103 is an internal electrode having conductivity, 104 is a sealing portion, and 105 is a high-frequency generation circuit. A substance that emits ultraviolet light such as xenon is sealed in the airtight container 101.

[0005] The hermetic container 101 is formed of quartz or the like.

The external electrode 102 is spirally wound around the outer peripheral surface of the airtight container 101 and mounted. As another form of the external electrode 102, for example, a mesh-like one is used (see FIG. 8).

The internal electrode 103 is, for example, a conductive member having a shape such as a coil shape, a bar shape, a line shape, and a plate shape, and is connected to an external lead wire 106 fixed to the sealing portion 104.

The high-frequency generation circuit 105 includes an external electrode 102
A voltage is applied between the electrode and the internal electrode 103 to supply electric energy required for dielectric barrier discharge.

In such a structure, a high frequency generating circuit 105 applies a voltage between the external electrode 102 and the internal electrode 103 so that these external electrodes 102
And a dielectric barrier discharge is generated between the internal electrode 103 and the internal electrode 103. This dielectric barrier discharge is a so-called silent discharge, and a discharge current flows in a pulse shape through a dielectric portion between the external electrode 102 and the internal electrode 103. 9 and 10
FIG. 1 schematically shows a state in which such a dielectric barrier discharge occurs. Such a pulsed current has a high-speed electron flow and temporarily couples a substance that emits ultraviolet light such as xenon sealed in the hermetic container 101 into a molecular state (excimer state). A substance that emits ultraviolet light, such as xenon, efficiently emits ultraviolet light with little re-absorption when returning from the molecular state to the atomic ground state. This is the light emission principle of the dielectric barrier discharge lamp.

[0010] As illustrated in FIG.
When a mesh structure 2 is used, discharge occurs stably over a large area, and light emission is observed near the intersection of the meshes during stable discharge.

[0011]

[Flickering of Light Emission] In the dielectric barrier discharge lamp illustrated in FIG. 7 and FIG.
The distance of the dielectric portion between the external electrode 102 and the internal electrode 103 is long, and a positive column is generated during light emission after starting. The positive column is not necessarily generated uniformly in the tube length direction because the internal electrode 103 is linear and the cathode site when the internal electrode 103 is in a cathode cycle is not determined. As a result, there is a problem that the discharge distribution in the axial direction of the internal electrode 103 becomes non-uniform, and flickering of light emission occurs.

[Starting Voltage, Sustaining Voltage] In the dielectric barrier discharge lamp illustrated in FIGS. 7 and 8, since the distance of the dielectric portion between the outer electrode 102 and the inner electrode 103 is long, the starting voltage and the sustaining voltage are reduced. There is a problem that the maintenance voltage is inevitably increased.

[Emission efficiency] In the case of a dielectric barrier discharge lamp having a wire-shaped external electrode 102 as illustrated in FIG. 7, the external electrode 102 must be in contact with the hermetic container 101 with a certain degree of adhesion. Airtight container 10
If there is a lot of floating which is a non-contact portion between the first electrode and the external electrode 102, the luminous efficiency is reduced. On the other hand, the airtight container 10
If the external electrode 102 must be wound with a contact ratio of 100% with respect to 1, the production of the dielectric barrier discharge lamp becomes difficult. On the other hand, conventionally, no research and development have been made on the adhesion ratio between the airtight container 101 and the external electrode 102.

Further, the dielectric barrier discharge lamp generates heat as its light emission continues, which causes a reduction in luminous efficiency.

[Exhaust Chip] Since gas such as xenon needs to be introduced into the hermetic container 101, an exhaust chip protruding from the outer peripheral surface is generated. Such an exhaust chip is not necessarily generated by a method of introducing a gas into the airtight container 101, but a gas introduction method that generates an exhaust chip is generally employed. However, if the wire-shaped external electrode 102 illustrated in FIG. 7 or the mesh-shaped external electrode illustrated in FIG. 8 is applied to this portion, the light emission of this portion is determined based on the thickness of the tube of the hermetic container 101 which is a dielectric. There is a problem that efficiency is reduced and uneven light emission occurs.

In particular, in the case of the wire-like external electrode 102 illustrated in FIG. 7, if it is applied to this portion, a slip may occur between the portion and the airtight container 101 and the portion may be loosened. There is.

[Uniformity of light emission] Xenon, which is generally used as a substance that emits ultraviolet light, has a large number of atoms and is heavy.
For this reason, convection of a gas mainly composed of xenon hardly occurs inside the hermetic container 101, which causes a problem that uneven light emission easily occurs in the tube length direction of the hermetic container 101.

[Use as a germicidal lamp] As a use of a dielectric barrier discharge lamp, application to a germicidal lamp has been conventionally performed. This is because the wavelength of xenon, which is a light-emitting substance in a dielectric barrier discharge lamp, is about 172 nm, and the absorption peak of oxygen in this wavelength region promotes the production of ozone. This is because organic substances adhering to the surface are decomposed and sterilized.

On the other hand, a dielectric barrier discharge lamp is
As the light emission continues, heat is generated. On the other hand, when the dielectric barrier discharge lamp is used as a germicidal lamp, some objects to be sterilized are weak to heat. However, since the dielectric barrier discharge lamp generates heat by continuing its light emission, there is a problem that the object to be sterilized may be damaged.

[Problem Specific to Mesh Electrode] When the external electrode 102 as illustrated in FIG.
Since the ratio of the external electrode 102 on the surface of the hermetic container 101 is inevitably large, the external electrode 102 hinders the path of light, and there is a problem that the light emission intensity on the surface of the hermetic container 101 is weakened.

[Problem peculiar to the spirally wound electrode] Such a problem is a problem that occurs even when the winding pitch is too narrow, even if the external electrode 102 is exemplified in FIG.

On the other hand, in the dielectric barrier discharge lamp having the external electrodes 102 as illustrated in FIG. 7, if the winding pitch of the external electrodes 102 is too wide,
There is a problem that a voltage drop occurs between the electrode and the internal electrode 103, and the ultraviolet ray conversion efficiency deteriorates. in addition,
The winding pitch of the external electrode 102 is too wide,
When a voltage drop occurs between the internal electrode 103 and the internal electrode 103, the discharge distribution in the axial direction of the internal electrode 103 becomes non-uniform, and as a result, flickering of light emission occurs.

An object of the present invention is to prevent flicker of light emission.

Another object of the present invention is to keep the starting voltage and the maintenance voltage low.

Another object of the present invention is to obtain uniform light emission without uneven light emission in the tube length direction.

Another object of the present invention is to improve luminous efficiency.

Another object of the present invention is to improve mechanical strength.

Another object of the present invention is to reduce the amount of heat generated,
When used as a germicidal lamp, it is intended to reduce the influence of heat on an object to be sterilized.

Another object of the present invention is to improve the light emission intensity.

[0030]

According to the first aspect of the present invention, there is provided a dielectric barrier discharge lamp having a tubular airtight container made of a material which transmits ultraviolet light, and a spiral shape disposed along the inner peripheral surface of the airtight container. An excimer product gas enclosed in an airtight container; and an external electrode mounted on the outer periphery of the airtight container.

Therefore, when a voltage is applied between the external electrode and the internal electrode, a dielectric barrier discharge occurs between the two electrodes. As a result, the excimer product gas sealed in the airtight container is temporarily combined with a molecular state (excimer state), and when returning from such a molecular state to the ground state of atoms, ultraviolet rays with little re-absorption are efficiently emitted. Therefore, the dielectric barrier discharge lamp emits light. The wavelength range of the emitted ultraviolet light is
Depends on the type of excimer gas generated in the airtight container,
For example, when a large amount of xenon is encapsulated, 172n
Ultraviolet light having a wavelength of m is emitted.

Further, the internal electrode and the external electrode face each other via the airtight container, and both are kept in contact with the airtight container. Therefore, at the time of light emission after starting the lamp, a positive column hardly occurs between the internal electrode and the external electrode. Thus, the discharge distribution in the axial direction of the internal electrode becomes uniform, and uniform light emission without flickering of light emission can be obtained. Further, since the distance of the dielectric portion between the external electrode and the internal electrode is short, it is possible to light and emit light well even at a low starting voltage and a low sustaining voltage.

According to a second aspect of the present invention, there is provided a dielectric barrier discharge lamp, comprising: a tubular hermetic container made of a material that transmits ultraviolet light; an internal electrode sealed in the hermetic container; and an excimer generated gas sealed in the hermetic container. And having a wire diameter of 0.3 mm or less, and 0.5 mm or more and 1.3 m on the outer periphery of the airtight container.
and a wire-shaped external electrode wound spirally at a pitch of not more than m.

Therefore, when a voltage is applied between the external electrode and the internal electrode, a dielectric barrier discharge occurs between the two electrodes. As a result, the excimer product gas sealed in the hermetic container is temporarily bonded to a molecular state (excimer state), and when returning from such a molecular state to the ground state of atoms, ultraviolet rays with little re-absorption are efficiently emitted. , The dielectric barrier discharge lamp emits light. The wavelength range of the emitted ultraviolet light depends on the type of excimer-producing gas sealed in the airtight container. For example, when a large amount of xenon is sealed, ultraviolet light having a wavelength of 172 nm is emitted.

In the present invention, the ratio of the external electrodes on the surface of the airtight container is optimized. This prevents a problem caused by the winding pitch of the external electrodes being too close, that is, preventing the external electrodes from interfering with the light path and reducing the light emission intensity on the surface of the airtight container. In addition, the problem that the winding pitch of the external electrode is too sparse, that is, a voltage drop occurs between the external electrode and the internal electrode, thereby deteriorating the ultraviolet conversion efficiency, and This prevents the discharge distribution in the direction from becoming non-uniform and causing flickering of light emission.

According to a third aspect of the present invention, in the dielectric barrier discharge lamp according to the second aspect, the hermetic container has an exhaust chip on an outer peripheral surface thereof, and the external electrode has an outer peripheral portion at a position separated from the exhaust chip. It is characterized by being wound around.

An exhaust pipe is connected to the peripheral surface of the airtight container as a means for evacuating the inside of the airtight container and then sealing the excimer generated gas therein. After exhausting through the exhaust pipe, the excimer product gas is sealed in the airtight container from the exhaust pipe, and then the exhaust pipe is chipped off to form an exhaust chip. By providing the exhaust tip on the peripheral surface of the hermetic container in this way, the operation of connecting the exhaust pipe and the operation of exhausting / sealing are facilitated.

On the other hand, the air-tight container has a thick tube at the exhaust chip. For this reason, if an external electrode is applied to the exhaust chip portion, the luminous efficiency of this portion is reduced due to the thickness of the tube of the hermetic container, which is a dielectric material, and uneven light emission occurs. There is. In the present invention, such a problem is solved by a configuration in which the external electrode is wound around the outer periphery of the airtight container at a position separated from the exhaust tip. Further, when the external electrode is applied to the exhaust chip portion, the external electrode is easily loosened, and there is a problem that the mechanical strength is reduced. The present invention, which has a configuration in which the external electrode is wound around the outer periphery of the airtight container at a position separated from the exhaust tip, also solves such a problem.

The invention described in claim 4 is the second or third invention.
In the described dielectric barrier discharge lamp, the external electrode is
A feature is that 70% or more of the length is in contact with the outer peripheral surface of the airtight container.

Therefore, the amount of floating which is a non-contact portion between the airtight container and the external electrode is optimized. That is, when 70% or more of the external electrode is in contact with the outer peripheral surface of the hermetic container as in the present invention, the luminous efficiency does not decrease due to the floating of the external electrode with respect to the hermetic container. In the present invention, since the floating of the outer electrode with respect to the airtight container is allowed in a portion of less than 30% of the external electrode, the manufacture of the dielectric barrier discharge lamp is facilitated.

The fifth aspect of the present invention is the second aspect of the present invention.
The dielectric barrier discharge lamp according to any one of the above,
A tubular outer tube for accommodating an airtight container with a gap for an inert gas flow path provided between the pipe walls is further provided, and the outer tube has an inlet for introducing the inert gas into the flow path. It is characterized by the following.

Here, for example, nitrogen is used as the inert gas.

Therefore, a cooling medium such as an inert gas can be guided from the inflow port to the flow path formed between the hermetic container and the outer tube, whereby the temperature of the hermetic container whose temperature tends to rise due to light emission can be increased. It is possible to lower the temperature. Therefore, a rise in temperature when light emission continues is suppressed, and light emission efficiency is maintained high.

When applied to a germicidal lamp, the temperature rise is suppressed by introducing an inert gas into a flow path formed between the outer tube and the airtight container. It is less likely to damage objects.

The invention according to claim 6 is the invention according to claims 2 to 5
The dielectric barrier discharge lamp according to any one of the above,
The excimer product gas is characterized in that it is a mixture gas of xenon of 70% or more and an inert gas having a specific gravity smaller than that of xenon, specified at a total pressure of 300 torr or more.

Therefore, since the excimer product gas is mixed with the inert gas having a specific gravity smaller than that of xenon, convection of the excimer product gas easily occurs inside the hermetic container, and convection of the excimer product gas hardly occurs. As a result, uneven light emission in the tube length direction of the airtight container and variations in the rise time are prevented.

According to a seventh aspect of the present invention, there is provided a dielectric barrier discharge lamp device, comprising: the dielectric barrier discharge lamp according to any one of the first to sixth aspects; and between the internal electrode and the external electrode of the dielectric barrier discharge lamp. And a high-frequency generation circuit for applying a high-frequency voltage to the power supply.

Therefore, the high-frequency generation circuit generates a dielectric barrier discharge between both electrodes by applying a voltage between the internal electrode and the external electrode. As a result, the excimer product gas sealed in the hermetic container is temporarily bonded to a molecular state (excimer state), and when returning from such a molecular state to the ground state of atoms, ultraviolet rays with little re-absorption are efficiently emitted. , The dielectric barrier discharge lamp emits light. The wavelength range of the emitted ultraviolet light depends on the type of excimer-producing gas sealed in the airtight container. For example, when a large amount of xenon is sealed, ultraviolet light having a wavelength of 172 nm is emitted. The light emitting dielectric barrier discharge lamp has the function and effect of the invention according to any one of claims 1 to 6.

Here, the dielectric barrier discharge lamp device of the present invention is applicable to, for example, an ultraviolet irradiation device.
“Ultraviolet irradiation device” means any device that utilizes ultraviolet light generated from a dielectric barrier discharge lamp. For example, there are a semiconductor stepper, a light cleaning device, a light curing device, a light drying device, and the like.

Next, in the present invention, the definitions and technical meanings of the terms are as follows unless otherwise specified.

[Airtight Container] An airtight container made of a material that transmits ultraviolet light can be generally manufactured using quartz glass. However, in the present invention, the airtight container may be made of any material as long as it has ultraviolet transmittance.

The airtight container is not limited to a straight tube as long as it is tubular, and may be curved.

[Internal Electrode] The internal electrode is made of a heat-resistant metal such as nickel, tungsten, molybdenum, or the like.
Except for the invention according to claim 1, which is made of a metal such as stainless steel or titanium and has a feature in the internal electrode, the internal electrode has a rod shape, a linear shape, a plate shape, or the like, and is sealed inside an airtight container. However, at least one end is sealed to the end of the airtight container. The other end of the internal electrode may be fixed and supported inside the airtight container by an appropriate means. However, if the other end of the internal electrode is sealed to the end of the airtight container like the one end, the fixing of the internal electrode to the airtight container becomes easy and reliable. In terms of material, tungsten has a relatively small function, so that electrons are easily emitted, which is effective in lowering the starting voltage.

The internal electrode according to the first aspect of the present invention has a diameter of, for example, 1 mm, and its winding pitch is preferably about 5 mm.

Further, in order to seal the internal electrode to the end of the airtight container made of quartz glass, a sealing structure using a sealing metal foil which is frequently used when sealing the quartz glass compactly is adopted. be able to. Further, the sealing metal foil can be hermetically sealed by pinch sealing the quartz glass.

Further, it has been found that the configuration in which the internal electrodes are heated by energization promotes the generation of electrons, increases the lamp current, and also reduces the discharge starting voltage and the discharge sustaining voltage. In order to adapt to the electric heating, it is preferable to form the internal electrode, for example, a tungsten filament in a coil shape. In this case, the internal electrodes are heated using a filament heating power supply.

Further, a dielectric layer can be formed on the surface of the internal electrode as needed. By forming the dielectric layer, the intensity of the electric field near the internal electrode can be increased to increase the emission of ultraviolet light.

Further, in the inventions according to the second to sixth aspects, since the internal electrode cannot be made to absorb the difference in the coefficient of thermal expansion between the internal electrode and the hermetic container at the time of manufacture, the internal electrode is made longer and therefore easily sags. In addition, even when the temperature becomes high during lighting, it is thermally expanded and loosened. If the internal electrodes are loosened, the characteristics as designed will not be obtained.

Therefore, in order to prevent the internal electrodes from being loosened, a supporting means for supporting the intermediate portion even if it is thin may be used.

Incidentally, as a supporting means, a supporting wire can be engaged with an intermediate portion of the internal electrode, and the base end of the supporting wire can be fixed by welding to the exhaust tip.

[Excimer-producing gas] As the excimer-producing gas, a rare gas such as xenon, krypton or argon or a mixed gas of a rare gas and a halogen such as fluorine, chlorine, bromine or iodine can be used. The sealing pressure of the excimer generated gas affects the ultraviolet output and the startability. An appropriate pressure for filling the excimer generation gas is, for example, about 10 to 70 kPa.

[External Electrode] The external electrode functions to generate a dielectric barrier discharge between the internal electrode and the internal electrode. In order to lead the ultraviolet light emitted from the excimer generated by the dielectric barrier discharge to the outside, Mesh structures have been traditionally employed to increase UV emission. In the present invention, in the invention of claim 1,
Preferably, the external electrodes are formed in a mesh structure.

In order to lock the mesh structure of the external electrode to the exhaust chip, the mesh structure developed in a plate shape is wrapped around the side of the airtight container, and the mesh portion is pressed into the exhaust chip, and both ends are abutted. After overlapping, the wire may be tied through a wire to the mesh portion at the end of the mesh structure, or may be fixed using a mechanical locking tool bent in a U-shape or the like. In addition, the mesh structure is formed in advance into a cylindrical shape having a diameter larger than that of the airtight container, and the airtight container is inserted therein,
The both ends of the mesh structure can be grasped and pulled to reduce the diameter of the mesh structure, and the mesh portion can be brought into close contact with the outside of the airtight container while being locked to the exhaust chip.

On the other hand, in the inventions according to the second to sixth aspects, the external electrode is formed in a wire shape having a wire diameter of 0.3 mm or less, and is formed on the outer periphery of the airtight container with a diameter of 0.5 mm or more and 1.3 mm or less. It is spirally wound at the pitch and mounted. Such an external electrode can be formed using a suitable metal, for example, stainless steel, nickel, silver, gold, platinum, or the like.

The materials, substances, dimensions, manufacturing methods, and the like applicable to the present invention have been described above. However, these limitations are merely examples when the present invention is applied.
It goes without saying that the present invention is not limited to the above materials, substances, dimensions, manufacturing methods, and the like.

[0066]

FIG. 1 shows a first embodiment of the present invention.
A description will be given based on FIG.

FIG. 1 is a front view of a dielectric barrier discharge lamp showing a part of an external electrode in section, FIG. 2 is a vertical sectional side view thereof, and FIG. 3 is an axial position and UV of the dielectric barrier discharge lamp.
It is a graph which shows the relationship with intensity.

1 and 2, 1 is an airtight container,
2 is an internal electrode, 3 is an external lead wire, and 4 is an external electrode.

The airtight container 1 is made of quartz glass and has an elongated cylindrical hollow portion 1a having an outer diameter of 12 mm and an inner diameter of 10 mm.
A sealing portion 1b formed at both ends of the hollow portion 1a and an exhaust chip 1c formed on the peripheral surface of the hollow portion 1a;
The total length is 300 mm.

The sealing portion 1b has a pinch seal structure in which the molybdenum foil 11 is embedded.

The exhaust tip 1c is preferably formed to have a sharp tip.

Xenon is sealed in the hollow portion 1a of the airtight container 1 as an excimer generation gas.

As the internal electrode 2, a wire-like one is used, and such an internal electrode 2 has a spiral shape arranged along the inner peripheral surface of the airtight container 1. This internal electrode 2
Has a diameter of 1 mm, for example, and the winding pitch is set to about 5 mm. The winding diameter of the internal electrode 2 is set to 10 mm so that the maximum diameter thereof matches the inner diameter of the airtight container 1 of 10 mm. The internal electrode 2 is supported at both ends by sealing portions 1 b formed at both ends of the airtight container 1 and is welded to one end of the molybdenum foil 11.

An external lead wire 3 is welded to the other end of the molybdenum foil 11.

The external electrode 4 is formed by shaping the mesh structure into a cylindrical shape, surrounds the outer surface of the airtight container 1 over the entire circumference, and is fixed to the exhaust tip 1c.

The mesh structure of the external electrode 4 is a knitted braided structure formed by braiding a stainless steel wire (# 304) having a wire diameter of 0.1 mm. The mesh interval is 2.8 mm long and 3 mm wide.

Further, in order to mount the external electrode 4 on the airtight container 1, the knitted braided structure is formed into a cylindrical body having a diameter of 20 mm, and the airtight container 1 is inserted into the cylindrical body. And pull it toward both ends. Then, the cylindrical body contracts while the mesh is deformed by being elongated. The exhaust tip 1c pushes and expands the mesh portion in the process of pulling the cylindrical body, penetrates the external electrode 4, and projects outside. The cylindrical body is deformed from the portion through which the exhaust tip 1c penetrates, adheres to the airtight container 1, and gradually expands in both ends after the shape is stabilized. Therefore, the mesh is deformed into a rhombus, but the shape is stable and airtight. The state of being in close contact with the container 1 is maintained. Since the exhaust tip 1c penetrates the external electrode 4, the external electrode 4 is fixed to the airtight container 1 and does not drop out carelessly.

Thus, the dielectric barrier discharge lamp 51 is formed. The dielectric barrier discharge lamp 51 thus formed is connected to the high-frequency generation circuit 5 and is energized and turned on by the high-frequency generation circuit 5. The high frequency generation circuit 5
A high-frequency inverter having a DC power supply as an input power supply is mainly constituted, and its high-frequency output is applied between the internal electrode 2 and the external electrode 4 of the dielectric barrier discharge lamp 51.
The high-frequency generation circuit 5 and the dielectric barrier discharge lamp 51 constitute a dielectric barrier discharge lamp device.

In such a configuration, when a voltage is applied between the external electrode 4 and the internal electrode 2, a dielectric barrier discharge occurs between the electrodes 2 and 3. Thereby, the airtight container 1
The excimer product gas encapsulated in the gas temporarily combines into a molecular state (excimer state), and when returning from such a molecular state to the atomic ground state, efficiently emits ultraviolet light with little re-absorption, thereby causing a dielectric barrier discharge. The lamp 51 emits light. The wavelength range of the emitted ultraviolet light depends on the type of excimer-producing gas sealed in the airtight container 1. For example, when a large amount of xenon is sealed, ultraviolet light having a wavelength of 172 nm is emitted.

The internal electrode 2 and the external electrode 4 face each other via the hermetic container 1 and are both kept in contact with the hermetic container 1. Therefore, at the time of light emission after starting the lamp, a positive column hardly occurs between the internal electrode 2 and the external electrode 4. Therefore, the discharge distribution in the axial direction of the internal electrode 2 becomes uniform, and uniform light emission without flickering of light emission is obtained.

FIG. 3 is a graph showing the relationship between the axial position of the dielectric barrier discharge lamp 51 and the UV intensity. This graph shows a case where the winding pitch of the external electrode 4 is set to 5 mm as in the present embodiment and a case where the winding pitch is set to 20 mm. When the winding pitch of the external electrode 4 is set to 5 mm, the UV intensity at the axial position of the dielectric barrier discharge lamp 51 hardly varies. On the other hand, when the winding pitch of the external electrode 4 is set to 20 mm, the UV intensity at the axial position of the dielectric barrier discharge lamp 51 varies. That is, such a phenomenon appears as flickering of light emission in the dielectric barrier discharge lamp 51.

Further, in this embodiment, since the distance between the external electrode 4 and the internal electrode 2 in the dielectric portion is short, good lighting and light emission are obtained even at a low starting voltage and a low sustaining voltage.

A second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a vertical sectional front view of the dielectric barrier discharge lamp 51, and FIG. 5 is a vertical sectional side view thereof.

4 and 5, reference numeral 1 denotes an airtight container,
2 is an internal electrode, 3 is an external lead wire, and 4 is an external electrode.

The hermetic container 1 is made of quartz glass and has an elongated cylindrical hollow portion 1a having an outer diameter of 12 mm, sealing portions 1b formed at both ends of the hollow portion 1a, and exhaust air formed on the peripheral surface of the hollow portion 1a. Equipped with chip 1c, total length 300mm
It is.

The sealing portion 1b has a pinch seal structure in which the molybdenum foil 11 is embedded.

The exhaust tip 1c is preferably formed to have a sharp tip.

[0086] The interior of the hollow portion 1a of the airtight container 1 contains a large amount of xenon as an excimer-producing gas. More specifically, this excimer product gas has a total pressure of 300 torr.
r or more. The excimer product gas is a mixed gas of xenon of 70% or more and an inert gas having a specific gravity smaller than xenon, for example, argon or neon.

The internal electrode 2 is made of a tungsten rod.
Both ends are supported by sealing portions 1 b formed at both ends of the hermetic container 1, and are welded to one end of the molybdenum foil 11.

The external lead wire 3 is welded to the other end of the molybdenum foil 11.

The external electrode 4 has a wire diameter of 0.3 mm or less, and is wound in a spiral shape at a pitch of 0.5 mm or more and 1.3 mm or less on the outer periphery of the airtight container. . Such an external electrode 4 is wound around the outer periphery of the airtight container 1 at a position separated from the exhaust tip 1c. Further, a portion of the external electrode 4 that is 70% or more of its length is in contact with the outer peripheral surface of the airtight container 1.

Thus, the dielectric barrier discharge lamp 51 is formed. The dielectric barrier discharge lamp 51 thus formed is connected to the high-frequency generation circuit 5 and is energized and turned on by the high-frequency generation circuit 5. The high frequency generation circuit 5
A high-frequency inverter having a DC power supply as an input power supply is mainly constituted, and its high-frequency output is applied between the internal electrode 2 and the external electrode 4 of the dielectric barrier discharge lamp 51.

In such a configuration, when a voltage is applied between the external electrode 4 and the internal electrode 2, a dielectric barrier discharge occurs between the electrodes 2 and 3. Thereby, the airtight container 1
The excimer product gas encapsulated in the gas temporarily combines into a molecular state (excimer state), and when returning from such a molecular state to the atomic ground state, efficiently emits ultraviolet light with little re-absorption, thereby causing a dielectric barrier discharge. The lamp 51 emits light. The wavelength range of the emitted ultraviolet light depends on the type of excimer-producing gas sealed in the airtight container 1. For example, when a large amount of xenon is sealed, ultraviolet light having a wavelength of 172 nm is emitted.

In this embodiment, the external electrode 4 is
It has a wire diameter of 0.3 mm or less, and is spirally wound around the outer periphery of the hermetic container 1 at a pitch of 0.5 mm or more and 1.3 mm or less. The ratio occupied by 4 is optimized. This prevents a problem caused by the winding pitch of the external electrode 4 being too close, that is, preventing the external electrode 4 from blocking the light path and reducing the light emission intensity on the surface of the airtight container 1. . In addition, the problem that the winding pitch of the external electrode 4 is too sparse, that is, a voltage drop between the external electrode 4 and the internal electrode 2 occurs, which deteriorates the ultraviolet conversion efficiency, and It is possible to prevent the discharge distribution in the axial direction of the electrode 2 from becoming uneven and causing flickering of light emission.

Further, since the external electrode 4 is wound around the outer periphery of the airtight container 1 at a position separated from the exhaust chip 1c, the dielectric barrier discharge lamp 51 according to the present embodiment is used.
Thus, a decrease in luminous efficiency due to the external electrode 4 being applied to the exhaust chip 1c is reliably prevented. In addition, the external electrode 4 is not easily loosened due to the portion of the exhaust tip 1c that is applied to the exhaust chip 1c, thereby preventing a decrease in mechanical strength.

In the dielectric barrier discharge lamp 51, the outer electrode 4 is in contact with the outer peripheral surface of the hermetic container 1 at a portion having a length of 70% or more. Thereby, the amount of floating between the airtight container 1 and the external electrode 4 is optimized. That is, as in the present embodiment, the external electrode 4
Assuming that a portion of 0% or more is in contact with the outer peripheral surface of the hermetic container 1, a decrease in luminous efficiency due to floating of the external electrode 4 with respect to the hermetic container 1 does not occur. In addition, since the floating of the external electrode 4 with respect to the airtight container 1 is allowed in a portion of less than 30%, the dielectric barrier discharge lamp 5
1 is facilitated.

Further, in the present embodiment, as an excimer producing gas, 70% or more of xenon is mixed with an inert gas such as argon or neon having a specific gravity smaller than that of xenon. Therefore, convection of the excimer-producing gas easily occurs inside the hermetic container 1, and uneven light emission in the tube length direction of the hermetic container 1 due to the difficulty of convection of the excimer-producing gas is prevented.

A third embodiment of the present invention will be described with reference to FIG.

FIG. 6 is a vertical sectional front view of the dielectric barrier discharge lamp 51.

In this embodiment, the dielectric barrier discharge lamp has a double tube structure in which the dielectric barrier discharge lamp 51 introduced in the above-described embodiment is housed in the outer tube 52. The dielectric barrier discharge lamp 51 housed in the outer tube 52 is the same as the dielectric barrier discharge lamp 51 introduced as the first embodiment.
Barrier discharge lamp 5 introduced as an embodiment of the present invention.
It may be 1. Therefore, the dielectric barrier discharge lamp 51 introduced as the first or second embodiment is described.
The same parts as those shown in FIG.

The outer tube 52 is a member formed of quartz glass in the shape of a straight pipe, and a predetermined gap is formed between the outer tube 52 and the outer peripheral surface of the hermetic container 1 of the dielectric barrier discharge lamp 51 having a diameter of 12 mm. The one having a size capable of accommodating the dielectric barrier discharge lamp 51 is used.

A pair of plugs 53 for hermetically sealing the outer tube 52 with the dielectric barrier discharge lamp 51 housed therein are welded to both ends of the outer tube 52. These plugs 53 are provided with an inlet 54 for introducing an inert gas, for example, nitrogen gas, into an airtight space between the outer tube 52 and the dielectric barrier discharge lamp 51, and the inlet 54 is provided with an outer tube. A communication hole 55 is formed to communicate with an airtight space between the dielectric barrier discharge lamp 51 and the dielectric barrier discharge lamp 51. Therefore,
The nitrogen gas introduced into the hermetic space between the outer tube 52 and the dielectric barrier discharge lamp 51 from the inflow port 54 through the communication hole 55 flows into the outer wall of the hermetic container 1 of the dielectric barrier discharge lamp 51 and the outer tube. It is led to a flow path 56 for flowing inert gas formed between the inner wall 52 and the inner wall 52.

Next, a structure for connecting the external lead wires 3 extending from both ends of the dielectric barrier discharge lamp 51 to, for example, the high frequency generating circuit 5 will be described. Each of the pair of plugs 53 is sealed with a second external lead wire 57 penetrating both end surfaces thereof. These second external leads 57 are connected to the external leads 3 extending from both ends of the dielectric barrier discharge lamp 51 via the second molybdenum foil 58.

The nitrogen gas introduced from the inlet 54 into the flow path 56 for flowing inert gas formed between the outer wall of the hermetic container 1 and the inner wall of the outer tube 52 of the dielectric barrier discharge lamp 51. Is discharged outside through a discharge port (not shown) formed in the outer tube 52.

In such a configuration, in the dielectric barrier discharge lamp 51 of the present embodiment having a double tube structure,
The dielectric barrier discharge lamp 51 generates heat by its light emission. On the other hand, in the dielectric barrier discharge lamp of the present embodiment, the airtight container 1 is connected from the inflow port 54 through the communication hole 55.
It is possible to introduce a cooling medium such as nitrogen gas into a flow path 56 formed between the outer tube 52 and the outer tube 52. This allows
It becomes possible to lower the temperature of the hermetic container 1 whose temperature is about to rise due to light emission, and the temperature rise when light emission is continued is suppressed, so that the luminous efficiency is kept high.

When the dielectric barrier discharge lamp according to the present embodiment is applied to a germicidal lamp, nitrogen gas or the like introduced into a flow path 56 formed between the outer tube 52 and the airtight container 1 is used. Since the temperature rise is suppressed by the cooling medium,
It becomes difficult to damage heat-sensitive objects to be sterilized.

[0107]

According to the first aspect of the present invention, there is provided a dielectric barrier discharge lamp comprising: a tubular airtight container made of a material that transmits ultraviolet light; and an internal electrode having a spiral shape disposed along an inner peripheral surface of the airtight container. And; an excimer product gas sealed in the hermetic container; and an external electrode mounted on the outer periphery of the hermetic container, so that the discharge distribution in the axial direction of the internal electrode is made uniform and no flickering of light emission occurs. Uniform light emission can be obtained. Further, since the distance of the dielectric portion between the external electrode and the internal electrode is short, it is possible to satisfactorily light and emit light even at a low starting voltage and a low sustaining voltage.

According to a second aspect of the present invention, there is provided a dielectric barrier discharge lamp comprising: a tubular hermetic container made of a material that transmits ultraviolet light; an internal electrode sealed in the hermetic container; and an excimer generated gas sealed in the hermetic container. And having a wire diameter of 0.3 mm or less, and 0.5 mm or more and 1.3 m on the outer periphery of the airtight container.
m, and a wire-shaped external electrode that is helically wound and mounted at a pitch of not more than m, so that the ratio of the external electrode occupying on the surface of the airtight container can be optimized. The problem that occurs when the winding pitch of the external electrode is too close, that is, that the external electrode hinders the light path and the light emission intensity on the surface of the hermetic container can be prevented from being reduced, The problem is that the winding pitch of the electrodes is too sparse, that is, a voltage drop occurs between the external electrode and the internal electrode, thereby deteriorating the UV conversion efficiency, and the axial discharge of the internal electrode. It is possible to prevent the light emission from flickering due to uneven distribution.

According to a third aspect of the present invention, in the dielectric barrier discharge lamp according to the second aspect, the airtight container has an exhaust chip on an outer peripheral surface thereof, and the external electrode is provided at a position outside the exhaust chip. As a result, uniform light emission not affected by the presence of the exhaust chip can be obtained, and loosening of the external electrode at the exhaust chip portion can be prevented, thereby improving mechanical strength.

The invention according to claim 4 is the invention according to claim 2 or 3
In the described dielectric barrier discharge lamp, the external electrode is
Since a portion of 70% or more of the length is in contact with the outer peripheral surface of the hermetic container, it is possible to prevent a decrease in luminous efficiency due to the floating of the external electrode with respect to the hermetic container. Since the floating of the airtight container is allowed in the portion, the manufacture of the dielectric barrier discharge lamp can be facilitated. In other words, the present invention can provide a solution to the problem of reduced luminous efficiency and simplicity of manufacture, which are incompatible with each other, regarding the winding state of the external electrode around the outer peripheral surface of the hermetic container.

The invention according to claim 5 provides the invention according to claims 2 to 4
The dielectric barrier discharge lamp according to any one of the above,
A tubular outer tube for accommodating an airtight container with a gap for an inert gas flow path provided between the pipe walls is further provided, and the outer tube has an inlet for introducing the inert gas into the flow path. Therefore, by introducing an inert gas that functions as a cooling medium from the inflow port to the flow path formed between the airtight container and the outer tube, the temperature of the airtight container whose temperature tends to increase by light emission can be reduced. . Therefore, it is possible to suppress a rise in temperature when light emission continues, thereby maintaining high light emission efficiency. Also, when applied to a germicidal lamp,
By introducing an inert gas functioning as a cooling medium into a flow path formed between the outer tube and the airtight container, a temperature rise can be suppressed and a heat-sensitive sterilized object can be protected.

The invention according to claim 6 is the invention according to claims 2 to 5
The dielectric barrier discharge lamp according to any one of the above,
Since the excimer product gas is a mixed gas of xenon and inert gas having a specific gravity smaller than xenon of 70% or more, which is specified at a total pressure of 300 torr or more, convection of the excimer product gas easily occurs inside the hermetic container. Therefore, it is possible to prevent uneven light emission in the tube length direction of the hermetic container due to the difficulty of convection of the excimer generated gas.

According to a seventh aspect of the present invention, there is provided a dielectric barrier discharge lamp device, comprising: the dielectric barrier discharge lamp according to any one of the first to sixth aspects; And a high-frequency generation circuit that applies a high-frequency voltage to the dielectric barrier discharge lamp according to any one of claims 1 to 6 by the high-frequency generation circuit. The operation and effect of the invention according to any one of claims 1 to 6 can be produced in a discharge lamp.

[Brief description of the drawings]

FIG. 1 is a front view of a dielectric barrier discharge lamp showing a part of an external electrode in cross section as a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional side view thereof.

FIG. 3 is a graph showing a relationship between an axial position of a dielectric barrier discharge lamp and UV intensity.

FIG. 4 is a vertical sectional front view of a dielectric barrier discharge lamp according to a second embodiment of the present invention.

FIG. 5 is a vertical sectional side view thereof.

FIG. 6 is a vertical sectional front view of a dielectric barrier discharge lamp according to a third embodiment of the present invention.

FIG. 7 is a vertical sectional front view showing an example of a conventional dielectric barrier discharge lamp.

FIG. 8 is a vertical sectional front view showing another example of the conventional dielectric barrier discharge lamp.

FIG. 9 is a vertical sectional front view for explaining the light emission principle of a conventional dielectric barrier discharge lamp.

FIG. 10 is a side view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airtight container 1c Exhaust chip 2 Internal electrode 4 External electrode 5 High frequency generation circuit 51 Dielectric barrier discharge lamp 52 Outer tube 54 Inlet 56 Flow path

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Akihiko Tauchi 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Lighting & Technology Corporation (72) Inventor Eisaku Wada 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo Toshiba Lighting & Technology Corporation

Claims (7)

[Claims] 1. A tubular airtight container made of a material that transmits ultraviolet light; an internal electrode having a spiral shape disposed along an inner peripheral surface of the airtight container; an excimer product gas sealed in the airtight container; An external electrode mounted on the outer periphery of the container. 2. A tubular hermetic container made of a material that transmits ultraviolet light; an internal electrode sealed in the hermetic container; an excimer-producing gas sealed in the hermetic container; and a wire diameter of 0.3 mm or less. 0.5 mm or more on the outer periphery of the airtight container.
A wire-shaped external electrode which is helically wound and mounted at a pitch of 3 mm or less. 3. The dielectric according to claim 2, wherein the airtight container has an exhaust chip on an outer peripheral surface thereof, and the external electrode is wound around the outer periphery of the airtight container at a position separated from the exhaust chip. Barrier discharge lamp. 4. The dielectric barrier discharge lamp according to claim 2, wherein a portion of the external electrode having a length of 70% or more is in contact with the outer peripheral surface of the hermetic container. 5. A tubular outer tube for accommodating an airtight container with a gap serving as a flow path for inert gas between the respective pipe walls, wherein the outer tube guides the inert gas into the flow path. 5. The dielectric barrier discharge lamp according to claim 2, further comprising an inflow port. 6. The excimer product gas has a total pressure of 300 torr.
The dielectric barrier discharge lamp according to any one of claims 2 to 5, wherein the gas is a mixed gas of xenon of 70% or more and an inert gas having a specific gravity smaller than xenon, defined as r or more. 7. A dielectric barrier discharge lamp according to any one of claims 1 to 6, and a high frequency generating circuit for applying a high frequency voltage between an internal electrode and an external electrode of the dielectric barrier discharge lamp. And a dielectric barrier discharge lamp device.