JP2002319369A - Dielectric barrier discharge lamp and ultraviolet irradiation device - Google Patents

Abstract

(57) [Problem] To provide a dielectric barrier discharge lamp capable of obtaining high ultraviolet illuminance by using ultraviolet light radiated in a direction not directed to a work, and an ultraviolet irradiation device using the same. . Kind Code: A1 An internal electrode extending in an axial direction of an elongated tubular airtight container made of a material that transmits ultraviolet light is sealed, an excimer generated gas is sealed, and an external electrode is provided on an outer surface of the airtight container. A light-emitting tube LT, an elongated tubular outer tube OT for accommodating the light-emitting tube LT, and an ultraviolet-reflective reflector R disposed in the outer tube OT along its longitudinal direction. Further, the arc tube LT is constituted by a mesh-like electrode having a plurality of turns of a coil wound with the external electrode 3 in contact with the outer surface of the hermetic container 1, and the reflection plate R is made of an ultraviolet-reflective conductive material. At the same time, it can be arranged in contact with a plurality of turns of the coil constituting the external electrode 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a dielectric barrier discharge lamp and an ultraviolet irradiation apparatus using the same.

[0002]

2. Description of the Related Art An excimer discharge lamp, that is, a dielectric barrier discharge lamp, which emits a near-monochromatic radiation by causing a noble gas such as xenon or a mixed gas such as xenon or krypton and a chlorine gas or the like to emit silently, It is described in a number of documents and is conventionally known.
In the dielectric barrier discharge, a pulsed current flows due to a so-called silent discharge. This pulsed current has a high-speed electron flow and many pauses, so the substance that emits ultraviolet light, such as xenon, is temporarily combined with the molecular state (excimer state) and reabsorbed when returning to the ground state. Efficiently emits less UV rays.

[0003] Conventionally, a dielectric barrier discharge lamp generally used is, as disclosed in Japanese Patent No. 2854250, for example, in which an inner tube and an outer tube are separated from each other to form an annular end plate and a circular end plate. And a coaxial cylindrical discharge vessel formed by closing both ends. The outer tube also serves as a radiation outlet window. One of a pair of electrodes provided in the coaxial cylindrical discharge vessel is a conductive mesh electrode, and is mounted on the outer tube of the coaxial discharge vessel. The other electrode is a conductive thin-film electrode, formed on the inner tube of the coaxial discharge vessel,
Also serves as a reflector. In addition, bases are respectively attached to both end plates of the coaxial cylindrical discharge vessel, and are used for supporting a dielectric barrier discharge lamp. Then, a high frequency high voltage is applied between the conductive mesh electrode and the conductive thin film electrode from the power source,
Supplies the electrical energy required for dielectric barrier discharge.
(Prior art 1) Prior art 1 has a relatively large amount of ultraviolet rays generated, but has the following problems. That is, since a discharge occurs through two glass walls serving as dielectrics, a high-frequency high voltage of several kV is required. For this reason, the high-frequency transformer that generates a high voltage not only becomes extremely large but also difficult to manufacture and expensive. In addition, the structure of the discharge vessel is complicated, and the amount of quartz glass used increases, which also increases the cost.

On the other hand, Japanese Patent Application Laid-Open No. 11-111235
Japanese Patent Laid-Open Publication No. H11-157, discloses a dielectric barrier discharge lamp that stably performs a dielectric barrier discharge without applying a high voltage as described above using an elongated tubular airtight container. In this dielectric barrier discharge lamp, one of the electrodes is exposed and sealed as an internal electrode extending along the center axis direction in an elongated tubular airtight container filled with excimer-produced gas, and the other electrode is externally sealed. The electrodes are configured in a mesh structure. In addition, when the internal electrodes are electrically heated from the outside, the starting electrons can be emitted and the starting voltage can be greatly reduced. In addition, since it has a simple structure and uses a small amount of quartz glass, it can be obtained at low cost. (Prior art 2) However, in prior art 2, since the internal electrode expands and hangs down due to external heating, when the dielectric barrier discharge lamp is turned on horizontally, the vertical distance between the internal electrode and the external electrode increases. The distance between the electrodes in the direction tends to change along the longitudinal direction of the airtight container.

Japanese Patent Application Laid-Open No. Hei 7-272692 discloses a light-transmitting, elongated tubular, light-transmitting external electrode on the outer surface of a discharge vessel also serving as a first dielectric of a dielectric barrier discharge. There has also been proposed a structure provided with an inner electrode formed of a metal rod or a metal pipe having a ratio L / D of length L to diameter D of 30 or more inside. (Prior Art 3) However, Conventional Technique 3 has a problem that the internal electrode is vulnerable to vibration and impact because it is cantilevered.

On the other hand, the present inventors have proposed a configuration in which an internal electrode is provided by the action of tension, or a position restrictor, ie, an anchor is attached to the internal electrode, so that the internal electrode is drooped. Invented a dielectric barrier discharge lamp that suppresses the above. This invention is disclosed in Japanese Patent Application No. 11-25992.
No. 3 has been filed. (Prior Art 4) According to Prior Art 4, since the anchor is made of a conductive metal, the anchor also acts as a part of the inner electrode, so that the distance between the inner and outer electrodes is reduced and the startability is improved. .

Further, the present inventors housed the dielectric barrier discharge lamp of the prior art 4 in an outer tube made of a material which is further permeable to ultraviolet light and through which a gas such as nitrogen having little ultraviolet absorption is passed. Invented a dielectric barrier discharge lamp. Moreover, by forming the external electrode in a mesh shape having a spiral portion, the manufacture of the external electrode is facilitated. This invention is disclosed in Japanese Patent Application No. 11-259923.
No. has been filed. (Prior art 5) Prior art 5
According to this, it has become possible to mount the dielectric barrier discharge lamp in an exposed state on the ultraviolet irradiation device. This eliminates the need for a conventionally used flat light extraction window made of synthetic quartz glass. Originally, it was difficult to manufacture flat synthetic quartz glass, and there was a problem of high cost.
If a light extraction window having a larger area is required in accordance with the increase in the area of the work, this cannot be met. On the other hand, according to the related art 5, there is no restriction as described above.

[0008]

However, there is a demand for obtaining vacuum ultraviolet rays with higher illuminance.

Therefore, as a result of further study by the present inventors, the ultraviolet rays generated by the dielectric barrier discharge lamp are radiated in all directions around the axis, but only the ultraviolet rays radiated toward the work are actually used. It was found that the ultraviolet light emitted in other directions was not sufficiently utilized.

An object of the present invention is to provide a dielectric barrier discharge lamp capable of obtaining high ultraviolet illuminance by using ultraviolet rays radiated in a direction not directed to a work, and an ultraviolet irradiation apparatus using the same. And

It is another object of the present invention to provide a dielectric barrier discharge lamp in which the influence of the inductance and resistance of the external electrode is suppressed and an ultraviolet irradiation device using the same.

[0012]

A dielectric barrier discharge lamp according to the first aspect of the present invention is an elongated tubular hermetic container made of a material that transmits ultraviolet light, and is sealed in the hermetic container and extends in the axial direction of the hermetic container. An arc tube having an internal electrode, an excimer product gas sealed in an airtight container, and an external electrode disposed on the outer surface of the airtight container; an elongated tubular outer tube containing the arc tube; A UV-reflecting reflector disposed along the longitudinal direction.

In the present invention and each of the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

[0014] The dielectric barrier discharge lamp includes an arc tube, an outer tube and a reflector. Hereinafter, each component will be described.

<Regarding the arc tube> The arc tube is an airtight container,
An internal electrode, an excimer product gas and an external electrode are provided.

(About Airtight Container) An airtight container made of a material that transmits ultraviolet light can be generally manufactured using synthetic quartz glass. However, the present invention may be made of any material as long as it is transparent to vacuum ultraviolet light of the wavelength to be used.

The outer diameter and thickness of the airtight container are not particularly limited, but in order to increase the ultraviolet output, the outer diameter must be 12 mm.
It is better to do above. In order to reduce the starting voltage as much as possible, the outer diameter is preferably set to 25 mm or less. Further, the thickness is preferably 2 mm or less, and preferably about 0.3 to 1 mm.

The length of the airtight container is not limited at all, and may be any length, for example, about 50 cm to 1 m, depending on the required ultraviolet irradiation length.

In general, an exhaust pipe is connected to the airtight container as a means for evacuating the inside of the airtight container and then filling the excimer generated gas. In the present invention, when the exhaust pipe is connected, the exhaust pipe may be connected to any part of the airtight container, but by connecting the exhaust pipe to the side surface, the connection work of the exhaust pipe and the exhaust / sealing work become easy. When the gas is exhausted through the exhaust pipe, the excimer product gas is sealed in the airtight container from the exhaust pipe, and the exhaust pipe is chipped off, thereby forming an exhaust chip-off portion.

Further, the airtight container may be not only a straight tube but also a curved tube as long as it is tubular. The cross-sectional shape of the tube is generally circular, but a desired cross-sectional shape such as an ellipse or a square can be used if necessary.

(Regarding the Internal Electrode) The internal electrode is sealed in an airtight container along its axial direction. If the internal electrode extends along the axial direction inside the airtight container,
Although any configuration may be used, the starting voltage can be reduced by forming a mesh with a unit mesh portion. In the present invention, `` a large number of unit mesh portions are in the form of a mesh arranged via a gap in the axial direction of the airtight container '', and the unit mesh portions approach the inner wall surface of the airtight container, and Refers to a state in which they are spatially separated from each other in the axial direction of the airtight container, but are electrically connected. The unit mesh part is
It may be continuous in the circumferential direction or may be divided. Therefore, specifically, the unit mesh portion is allowed to have, for example, a ring shape (former of the former), a spiral shape or a coil shape (form of the latter), or a mesh shape. In the case of a mesh, the former or the latter belongs depending on the configuration of the mesh.

In the case where the unit mesh portions have a ring shape, a plurality of unit mesh portions are connected at a predetermined pitch by providing a connection portion extending in the axial direction of the airtight container, and It can be conductively connected. By configuring the connecting portion to extend along the central axis of the airtight container, the entire inner electrode is provided with a number of ring anchors (corresponding to a unit mesh portion), the filament of a halogen lamp for copying. And the manufacturing equipment can be diverted to facilitate the manufacturing. However, if necessary, a configuration in which the center axis of the airtight container is removed and the connecting portion is directly connected to the ring portion of the mesh-like portion may be adopted. The connecting portion may be a single linear line, or the outer diameter may be 20% of the inner diameter of the hermetic container.
The following coil shape may be used. Further, the connecting portion can be sealed in a state in which an appropriate value of tension, preferably 2 kg or more, acts in the central axis direction. In order to exert a tension, it is advantageous to form the internal electrode in a coil shape. Even if it is not a coil shape, a tension in the central axis direction can be applied to the connecting portion. Regardless of the shape of the connecting portion, sealing at both ends of the airtight container at both ends makes it easier to apply tension to the connecting portion. However, if necessary, the connecting portion is sealed to only one side of the airtight container at one end, and the other end is fixed to the sealing portion by appropriate means, such as an anchor wire, at the other end of the airtight container. Can also be tensioned.

On the other hand, when the unit mesh portion has a spiral shape or a mesh shape, the spiral or mesh portion also functions as a connecting portion, and many unit mesh portions are mechanically and mutually connected. Conductively connect.
However, the shape retention of the internal electrode can be further imparted by welding a connecting portion made of a single or a plurality of rods to a spiral or mesh unit mesh portion. Alternatively, when a spiral or mesh-shaped unit mesh portion is formed by using a winding frame instead of the connecting portion of the rod-like body, shape retention is improved. The winding frame may be either insulating or conductive. If any one of the above-described configurations is employed for the mesh-like portion, shape stability can be imparted to the entire internal electrode, and handling thereof can be facilitated.

Further, the internal electrode is arranged such that a product p · P of a pitch P (m) of the unit mesh portion with respect to an axial direction and a pressure p (Pa) of an excimer generation gas described later falls within a predetermined range. Be composed.

Further, in the present invention, even if the lamp pressure is improved by increasing the filling pressure of the excimer generation gas as described later, the distance between the unit mesh portion and the inner wall surface of the hermetic container is reduced. It can be 3 mm or less. When the distance is 3 mm or less, the discharge sustaining voltage can be suppressed to 1000 V or less under certain conditions.

Further, the material constituting the internal electrode is not particularly limited. For example, a refractory metal such as tungsten, molybdenum and nickel may be used. Tungsten and nickel have a relatively small work function.
Since electrons are easily emitted, it is effective in lowering the starting voltage.

Furthermore, 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 compactly sealing the quartz glass is adopted. can do. Further, the sealing metal foil can be hermetically sealed by pinch sealing the quartz glass.

(Regarding Excimer Product Gas) The excimer product gas may be a mixture of one or more rare gases such as xenon, krypton, argon or helium, or a mixture of a rare gas and a halogen such as fluorine, chlorine, bromine or iodine. XeCl, KrCl, or the like can be used. In addition, a gas that does not generate excimer, such as neon, may be mixed and used in addition to the excimer generating gas.

Further, the pressure of the excimer product gas is 20
000 Pa or more. As the pressure increases, the lamp efficiency increases and the ultraviolet output increases, but the lamp efficiency tends to saturate with increasing pressure. If the pressure of the excimer product gas is 20,000 Pa or more, a lamp efficiency of at least about half or more of the highest value of the lamp efficiency can be obtained.

(Regarding External Electrode) The external electrode acts to generate a dielectric barrier discharge using the wall surface of the airtight container as a dielectric between the internal electrode and the internal electrode. The external electrodes may be formed in a mesh shape in order to lead ultraviolet light emitted from the excimer generated by the dielectric barrier discharge to the outside and increase ultraviolet light emission. In the present invention, "the external electrode has a mesh shape",
The external electrode is substantially in contact with the outer surface of the hermetic container, and a number of unit mesh portions are arranged at predetermined pitches in the axial direction of the hermetic container via the respective gaps, and each unit mesh portion is arranged in the axial direction. Are electrically connected. However, the unit mesh portion may be continuous or divided in the circumferential direction. Therefore, specifically, the unit mesh portion is allowed to have, for example, a spiral shape (coil shape) or a mesh shape.

When the external electrode is formed in a mesh shape due to the spiral shape (coil shape),
By winding the metal wire around the outer surface of the hermetic container at a predetermined pitch, it is possible to form an external electrode composed of a plurality of turns of the coil. However, by spirally connecting the spiral portion of the external electrode with one or more conductive rods so as to short-circuit, the distribution of inductance to the external electrode is practically prevented, and the resistance of the external electrode is reduced. Can be greatly reduced. Thus, it is possible to suppress a decrease in the uniformity of the ultraviolet illuminance distribution generated in the axial direction due to inductance and resistance distributed in the external electrode in the axial direction of the airtight container. In addition, the conductive rod-shaped body can be sandwiched between the airtight container and the spiral portion, or can be joined by welding to the spiral portion from the outside.

On the other hand, when the external electrodes are formed in a mesh shape by forming a mesh shape, the mesh shape can be constituted by, for example, knitting, turtle shell, flat knitting, punching, or the like. . Since the knitted fabric is particularly excellent in elasticity, it is easy to prepare a cylindrical mesh structure with an inner diameter larger than the outer diameter of the airtight container, place it outside the airtight container, and pull it toward both ends. By reducing the diameter, the external electrode can be brought into contact with the outer surface of the airtight container. Also, wrap the mesh structure spread out in a plate shape around the side of the airtight container and abut or overlap the both sides, then tie it through a wire to the side edge of the mesh structure, or fold it into a U-shape etc. It may be secured using a curved mechanical lock.

The external electrodes can be formed using a suitable metal such as stainless steel, nickel, molybdenum, or the like.

Further, in order to increase the generation of ultraviolet rays due to the dielectric barrier discharge, the external electrodes are preferably formed in a mesh shape using a metal wire as thin as possible, preferably about 0.05 to 0.5 mm. .

<Regarding Outer Tube> The outer tube houses an arc tube inside, and is used directly by mounting a dielectric barrier discharge lamp on an ultraviolet irradiation device without using a flat light extraction window. enable. The outer tube is made of a material that transmits ultraviolet light, for example, synthetic quartz glass.

The arc tube is configured to be turned on when the inside of the outer tube is filled with a gas having low ultraviolet absorption such as nitrogen gas or argon. Since the gas is filled, heat generated in the arc tube by lighting through the gas is discharged to the outside to facilitate cooling of the arc tube. When nitrogen gas is used, nitrogen gas has higher thermal conductivity than air, so that better cooling than air can be performed. Further, since the gas is hardly attenuated even when the vacuum ultraviolet light passes through the gas, the gas is filled in the outer tube so that the short-wavelength ultraviolet light is hardly attenuated in the outer tube. By flowing the nitrogen gas through the outer tube, it is possible to cool the arc tube even if it generates a large amount of heat. However, by properly balancing the heat radiation of the arc tube, the inner diameter of the outer tube, and the nitrogen gas filling pressure,
The outer tube may be configured in a sealed-cut type.

Further, the outer tube and the arc tube are generally arranged concentrically, but they may be eccentric if necessary.
The specific configuration for housing the arc tube in the outer tube is not particularly limited, but when nitrogen gas is allowed to flow inside,
For example, heat-resistant end members are attached to both ends of the arc tube,
It is possible to adopt a structure in which both ends of the outer tube whose both ends are open are supported by a pair of end plate members. And nitrogen gas can be supplied and discharged through the end member. That is, a configuration is formed in which a pair of end members are provided with an air passage communicating with the inside and outside of the outer tube, one end member is connected to a nitrogen supply pipe, and the other end member is connected to a nitrogen discharge pipe. I do.

<About the Reflector> The reflector has at least a reflective surface which is reflective to vacuum ultraviolet rays radiated from the arc tube, and is disposed at an appropriate position in the outer tube along the longitudinal direction of the outer tube. .

Further, the reflection plate can be formed in a shape to cover substantially the upper half of the arc tube. However, if necessary, the shape may be such that the remaining portion is covered over a half circumference or more except for the portion directly facing the work, or the shape may be such that it covers only a part of the upper half portion.

Further, the reflector may be separated from the arc tube or may be in contact with the arc tube. When the reflection plate is disposed apart from the arc tube, the reflection plate can be supported between the opposing inner walls of the outer tube by using the elasticity of the reflection plate itself. When the reflector is provided in contact with the arc tube, it can be sandwiched between the airtight container of the arc tube and the external electrode. Further, the reflection plate can be arranged in a state of being in contact with the outer surface of the external electrode. In this case, the reflection plate may be welded to the external electrode or may be simply pressed.

<Other Configurations> Although not essential components of the present invention, the following configurations can be selectively added as desired.

1. Cap The caps having appropriate shapes and structures can be attached to both ends of the hermetic container in order to easily supply electricity to the arc tube of the dielectric barrier discharge lamp. In this case, the end member that supports the outer tube is formed of an insulating member such as ceramics, and this can be used as an insulating base of the base member to form the base member. It should be noted that one of the bases may be on the high voltage side and the other may be on the ground side, so that a structure suitable for each can be provided.

2 Regarding the outer tube holding portion In order to mount both ends of the outer tube to the ultraviolet irradiation device, a metal pipe made of stainless steel or the like can be mounted on both ends of the outer tube to reinforce the outer tube.

3 About Heat Pipe When nitrogen gas is allowed to flow from one end to the other end in the outer tube, the heat generated in the arc tube is conducted while the nitrogen gas flows, and the temperature of the nitrogen gas rises. Therefore, a temperature gradient is formed in the longitudinal direction of the arc tube. For this reason, the UV illuminance on the low-temperature side increases, and conversely, the UV illuminance on the high-temperature side decreases.

Therefore, a heat pipe can be thermally disposed in the longitudinal direction of the reflector in contact with the arc tube. Thereby, the heat on the high temperature side is transported to the low temperature side, and the temperature of the arc tube is averaged in the longitudinal direction. Therefore, the uniformity of the ultraviolet illuminance along the longitudinal direction of the arc tube is improved.

<Operation of the Present Invention> When an alternating current or a pulsed high-frequency voltage such as a sine wave or a rectangular wave is applied between the internal electrode and the external electrode, a pulsed dielectric material is applied between the external electrode and the internal electrode. A barrier discharge is generated to generate vacuum ultraviolet rays, which are resonance lines of the rare gas. For example,
When xenon is enclosed, mainly 172 nm ultraviolet rays are generated. Then, at least a part of the ultraviolet light radiated in a direction not facing the work is incident on the reflector and reflected,
Go to the direction of the work. For this reason, the UV illuminance on the surface of the work is increased.

Further, since the reflection plate is provided in the outer tube, the reflection surface thereof is hardly stained, and the maintainability is improved. At the same time, since the reflector is close to the arc tube, even if the reflector is relatively small, the reflection of ultraviolet rays is large.

According to a second aspect of the present invention, there is provided a dielectric barrier discharge lamp according to the first aspect.
The arc tube comprises a mesh-like electrode comprising a plurality of turns of a coil wound around the outer surface of the container in contact with the outer surface of the hermetic container; the reflector comprises an ultraviolet-reflective conductive material; And disposed in contact with a plurality of turns of the constituting coil.

The present invention defines a configuration in which the effect of inductance and resistance of the coil is suppressed by the reflector when the external electrode is a mesh-shaped electrode comprising a plurality of turns of the coil. That is, as described in claim 1, it is effective to use a conductive rod to suppress the influence of the inductance and resistance of the coil of the external electrode, but in the present invention, the function of the conductive rod is effective. Can also be used as a reflector.

Thus, in the present invention, since the reflector also functions as a conductive rod, the conductive rod can be omitted, and the configuration is simplified. Moreover, the ultraviolet illuminance on the work is increased by the reflection plate.

Further, since a plurality of turns of the external electrode are short-circuited by the reflector, the inductance of the coil is practically eliminated and the resistance is significantly reduced. Therefore, the uniformity of the ultraviolet illuminance in the longitudinal direction of the dielectric barrier discharge lamp is reduced. Is improved.

According to a third aspect of the present invention, there is provided a dielectric barrier discharge lamp according to the first or second aspect, wherein the internal electrodes are dispersed at connecting portions extending substantially along the axis of the hermetic container. And a mesh having a unit mesh portion composed of a plurality of ring-shaped portions mounted thereon.

The present invention defines a structure in which the unit mesh portion of the internal electrode is formed of a ring-shaped portion. The outer diameter of the ring-shaped portion is d (mm), and the inner diameter of the hermetic container is D (mm).
(Mm), d / D can satisfy the following expression. In addition, by setting the distance between the inner surface of the airtight container and the mesh-shaped portion to 3 mm or less, the discharge starting voltage is reduced and the startability is improved. 3 <d / D <1.0 The ring-shaped portion is preferably perpendicular to the axis of the airtight container, but may be inclined at ± 10 ° or less with respect to the perpendicular.

Further, both the connection portion of the internal electrode and the unit mesh portion including the ring-shaped portion can be formed of tungsten. However, the ring-shaped portion, that is, the unit mesh portion, may be formed using a dissimilar metal wire such as molybdenum or nickel.

Thus, in the present invention, the manufacture of the internal electrode is easy, and the droop of the connecting portion can be suppressed.

When the reflector is not provided, the ultraviolet radiation is reduced in the middle of the unit mesh portion adjacent to the internal electrode, so that the uniformity of the ultraviolet illuminance in the longitudinal direction of the dielectric barrier discharge lamp is deteriorated. On the other hand, in the present invention, the uniformity in the longitudinal direction is improved by the reflection plate.

According to a fourth aspect of the present invention, there is provided an ultraviolet irradiating apparatus comprising: the dielectric barrier discharge lamp according to any one of the first to third aspects; An irradiation apparatus main body; and a high-frequency lighting circuit for lighting a dielectric barrier discharge lamp.

In the present invention, the term "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. Further, the “ultraviolet irradiation device main body” means a remaining portion excluding the dielectric barrier discharge lamp and the high frequency lighting circuit from the ultraviolet irradiation device.

One or more dielectric barrier discharge lamps can be used as needed. When a plurality of dielectric barrier discharge lamps are arranged in parallel at a relatively small interval in the ultraviolet irradiation device main body, a reflector should be provided in the ultraviolet irradiation device main body located between adjacent dielectric barrier discharge lamps. Can be. With this reflector, the ultraviolet light which does not go from the dielectric barrier discharge lamp to the work or the built-in reflector is applied to the work by the reflector arranged in the ultraviolet irradiation device body located between the adjacent dielectric barrier discharge lamps. Can be reflected to

The high frequency lighting circuit is used for lighting a dielectric barrier discharge lamp. The high-frequency generator includes a high-frequency generator, generates a high-frequency voltage, and supplies the dielectric barrier discharge lamp with high-frequency power necessary for lighting the lamp. The dielectric barrier discharge lamp does not need to connect current limiting means in series unlike a general discharge lamp. However, if necessary, in order to adjust the lamp current to a predetermined value, lighting can be performed by connecting an impedance having an appropriate value in series. In addition, when the dielectric barrier discharge lamp is connected to the high-frequency lighting circuit, noise generation is reduced by grounding the external electrodes. Further, “high frequency” refers to a frequency of 10 kHz or more. However, preferably between 100 kHz and 2
MHz.

In the high frequency lighting circuit, it is preferable to apply a high frequency voltage of about 1500 V or less, preferably 700 to 1000 V, when the dielectric barrier discharge lamp is stably operated. Furthermore, the discharge starting voltage of the dielectric barrier discharge lamp is 2 to 2.3 kVp-p, and the high frequency lighting circuit can be easily started by increasing the secondary open circuit voltage to the starting voltage. In this case, it is preferable that the high frequency generating means is mainly composed of a parallel inverter because a high boosting ratio can be easily obtained. When the high-frequency output waveform is a sine wave, noise is reduced when the dielectric barrier discharge lamp is turned on. However, if necessary, a starting pulse voltage generating means can be used in addition to the high frequency generating means.

Further, it is preferable that the dielectric barrier discharge lamp and the high frequency lighting circuit are arranged at close positions, but they may be arranged at positions separated from each other if necessary.

[0063]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially sectional front view showing a first embodiment of the dielectric barrier discharge lamp of the present invention.

FIG. 2 is an enlarged cross-sectional view of the same.

FIG. 3 is an enlarged longitudinal sectional view of a main part of the same.

FIG. 4 is a partially sectional front view showing the arc tube.

FIG. 5 is an enlarged sectional view of an essential part of a dielectric barrier discharge lamp schematically showing a state of a dielectric barrier discharge.

In each of the figures, LT is an arc tube, OT is an outer tube, R is a reflector, B1 is a first base, B2 is a second base, and WH is a wire harness.

<Regarding the arc tube LT> The arc tube LT includes an airtight container 1, an internal electrode 2, an external electrode 3, a pair of lead wires 4,
4 and a conductive rod 5.

The hermetic container 1 is made of an ultraviolet-permeable material, and has an elongated cylindrical hollow portion 1a and sealing portions 1b formed at both ends of the hollow portion 1a. The sealing portion 1b
It has a pinch seal structure in which molybdenum foil 1b1 is embedded.

An excimer generated gas is sealed in the hollow portion 1a of the airtight container 1.

The internal electrode 2 comprises a connecting portion 2a, a number of unit mesh portions 2b, and straight portions 2c at both ends. The connecting portion 2a is mainly composed of a coil 2a formed by winding a thin metal wire. The unit mesh portion 2b is
and a large number of ring-shaped portions arranged at a constant pitch.
Both end linear portions 2c are formed by extending both ends of the connecting portion 2a. The internal electrode 2 is connected to one end of the molybdenum foil 1b1 of the sealing portion 1b formed at both ends of the hermetic container 1 with a tension of about 2 kg applied thereto.
Is welding. The internal electrode 2 connecting portion 2a is
It is stretched by the action of tension while mounted inside.

The external electrode 3 has a mesh shape.
A unit mesh portion 3a composed of a plurality of turns of a coil formed by closely winding a metal wire around the outer surface of the airtight container 1 at a constant pitch is formed by each turn of the coil.

The pair of introduction wires 4, 4 have inner ends welded to molybdenum foil 1 b 1 embedded in sealing portions 1 b formed at both ends of hermetic container 1, and base ends extending from sealing portion 1 b to the outside. It is exposed.

As shown in FIGS. 2 and 3, the conductive rod 5 is sandwiched between the airtight container 1 and the external electrode 3. That is, the conductive rod 5 is formed on the upper outer surface of the airtight container 1.
Is wound around the external electrode 3 to provide the conductive rod 5.

<Regarding Outer Tube OT> The outer tube OT is composed of an elongated tube 6 and a reinforcing tube 7 and includes first and second tubes 6 and 7 described later.
The arc tube LT is housed in a coaxial relationship through the base bodies B1 and B2. The elongated tube 6 is made of an ultraviolet-transmissive material whose both ends are open. The reinforcing pipe 7 is made of a stainless steel pipe, and is attached to the outside of both ends of the elongated pipe 5.

<Reflector R> The reflector R is formed by bending an aluminum plate into a semi-cylindrical cross section and is inserted into the upper half of the inner surface of the outer tube OT in the drawing.

<Regarding First Cap B1> The first cap B1 includes an insulating base 8 and a cap terminal 9. The insulating base 8 is fixed to the sealing portion 1b at one end of the arc tube LT with an inorganic adhesive, and one end of the outer tube OT is fitted to the outside. Further, an exhaust port (not shown) communicating between the inside and the outside is formed in the insulating base 8. The base terminal 9 is supported by the center of the insulating base 8 and is connected to the external electrode 3 of the arc tube LT. A part of the base terminal 9 protrudes from the first base body B1 to the outside, and an ultraviolet irradiation device main body (not shown). ) Is configured to be grounded.

<Regarding the Second Cap B2> The second cap B2 comprises an insulating base 8 and a cap terminal (not shown), like the first cap B1. The insulating base 8 is
The other end of the arc tube LT is fixed to the sealing portion 1b at the other end by an inorganic adhesive, and the other end of the outer tube OT is fitted to the outside thereof. In addition, an air supply port (not shown) communicating the inside and the outside is formed in the insulating base 8. The base terminal is supported by the center of the insulating base 8 and is connected to the internal electrode 2 of the arc tube LT via one of the lead wires 4 and partially protrudes from the insulating base 8 to the outside. WH connects. Then, the second base B2 is on the high voltage side.

<Regarding the Wire Harness WH> The wire harness WH includes an insulated wire 10, a socket 11 and a connection terminal 12. The socket 11 is connected to one end of the insulated wire 10 and is connected to a base terminal of the second base body B2. The connection terminal 12 is connected to the other end of the insulated wire 10 and is connected to a high voltage output terminal of a high frequency lighting circuit (not shown).

<About the Lighting State> When the dielectric barrier discharge lamp is turned on by applying a high-frequency AC voltage between the internal electrode 2 and the external electrode 3, as shown by the density of black spots in FIG. A strong dielectric barrier discharge is generated around the unit mesh portion 2b of the internal electrode 2, and vacuum ultraviolet rays are radiated.

Embodiment 1 (The structure is shown in FIGS. 1 to 4.) <Emission tube LT> Airtight container 1: made of synthetic quartz glass, outer diameter 20 mm,
Internal electrode 2: The connecting portion 2a has a coil shape formed by winding a thin tungsten wire having a diameter of 0.2 mm with an outer diameter of 1.4 mm and a coil pitch of 0.4 mm. Unit mesh part 2b
Has an outer diameter of 16 mm and a pitch of 10 mm in a ring-shaped portion in which a large number of thin nickel wires having a diameter of 0.2 mm are arranged.
It is. The distance between the inner surface of the airtight container 1 and the unit mesh portion 2b is 1.0 mm.

Excimer product gas: Xenon at a pressure of about 40
Sealed at kPa.

External electrode 3: A stainless steel thin wire having a diameter of 0.1 mm was wound at a pitch of 2 mm to form a mesh-like portion 3a comprising a plurality of turns of a coil. <Outer tube OT>: made of synthetic quartz glass, outer diameter 25 m
m, thickness 1.2 mm, length 1100 mm, nitrogen gas flow system <Reflector R>: high-purity aluminum plate <lighting conditions> Voltage between electrodes: 2 kVrms, frequency 250 kHz, sine wave FIG. It is an expanded principal part sectional view of the dielectric barrier discharge lamp which shows typically the state of the dielectric barrier discharge in 2nd Embodiment of a body barrier discharge lamp.

This embodiment is different in that the unit mesh portion 2b 'of the internal electrode 2 is formed of a coil. Also in this embodiment, a dielectric barrier discharge is generated and vacuum ultraviolet rays are radiated in substantially the same manner as in FIG.

FIG. 7 is a front view showing an arc tube and a reflector in a third embodiment of the dielectric barrier discharge lamp of the present invention. In the figure, the same parts as in FIG.
The same reference numerals are given and the description is omitted. The present embodiment is different in that the reflection plate R is sandwiched between the hermetic container 1 and the external electrode 3 of the arc tube LT.

FIG. 8 is a partially omitted cross-sectional view showing a fourth embodiment of the dielectric barrier discharge lamp according to the present invention. In the figure, the same parts as those in FIG. In the present embodiment, the reflection plate R is an arc tube LT.
And a plurality of heat pipes H between the reflector R and the external electrode.
The difference is that P is sandwiched. Note that the internal electrode 2 and the external electrode 3 are omitted.

FIG. 9 is a cross-sectional view of a main part showing an ultraviolet cleaning apparatus as a first embodiment of the ultraviolet irradiation apparatus of the present invention. In the figure, 21 is a dielectric barrier discharge lamp, 22
Denotes an ultraviolet irradiation device main body, and 23 denotes a work.

The dielectric barrier discharge lamp 21 has a structure employing any one of the embodiments shown in FIGS.
A plurality of these are arranged on the ultraviolet irradiation device main body 22 at small intervals, and three of them are shown in the figure. The same parts as those in FIG. 7 are denoted by the same reference numerals.

The ultraviolet irradiation device main body 22 includes an aluminum block, and has a concave groove 22a on its lower surface and a cooling water flow passage 22b inside.

The dielectric barrier discharge lamp 21 has an outer tube OT
Is supported in a state of being in thermal contact with the concave groove 22a of the ultraviolet irradiation device main body 22, and a high frequency lighting circuit (not shown).
The low-pressure side of the output terminal is connected to an external electrode using the ultraviolet irradiation device main body 22 as a conductive path. The ultraviolet irradiation device main body 22 is grounded.

The work 23 is composed of the dielectric barrier discharge lamp 2
1 is moved from the lower side to the outer surface of the outer tube OT of the dielectric barrier discharge lamp 21 to a position of 3 mm so as to be able to receive ultraviolet irradiation.

FIG. 10 shows a second embodiment of the ultraviolet irradiation apparatus according to the present invention.
It is principal part sectional drawing which shows the ultraviolet-ray cleaning apparatus as embodiment. In the figure, the same parts as those in FIG. The present embodiment is different from the first embodiment in that a reflector R 'is provided in an ultraviolet irradiation device main body 22 located between adjacent dielectric barrier discharge lamps 21 and 21.

[0094]

According to the first aspect of the present invention, an inner electrode extending in the axial direction of an elongated tubular airtight container made of a material that transmits ultraviolet light is sealed, an excimer-produced gas is sealed, and an external surface of the airtight container is externally mounted. A workpiece is provided by including an arc tube provided with electrodes, an elongated tubular outer tube accommodating the arc tube, and an ultraviolet-reflective reflector disposed in the outer tube along the longitudinal direction thereof. And a dielectric barrier discharge lamp that obtains high ultraviolet illuminance by using ultraviolet rays radiated in a direction that does not go toward the target.

According to the second aspect of the present invention, in addition to the above, the arc tube is formed of a mesh-shaped electrode provided with a unit mesh portion composed of a plurality of turns of a coil wound with the external electrode in contact with the outer surface of the airtight container. Since the reflector is made of an ultraviolet-reflective conductive material and is arranged in contact with a plurality of turns of the coil constituting the external electrode, the reflector also functions as a conductive rod. The conductive rod-shaped body can be omitted, simplifying the configuration, increasing the UV illuminance on the work by the reflector, and shorting multiple turns of the external electrode by the reflector, which affects the inductance and resistance of the coil. And a dielectric barrier discharge lamp in which the uniformity of the illuminance of ultraviolet rays in the longitudinal direction is improved.

According to the third aspect of the present invention, in addition to the above, the internal electrode is provided with a unit mesh portion composed of a plurality of ring-shaped portions which are separately mounted on connecting portions extending substantially along the axis of the airtight container. The provision of a dielectric barrier discharge lamp in which the internal electrode is easy to manufacture, the droop of the connecting portion can be suppressed, and the uniformity in the longitudinal direction is improved by the reflection plate. Can be.

According to a fourth aspect of the present invention, there is provided a dielectric barrier discharge lamp according to any one of the first to third aspects, and an ultraviolet irradiation device body provided with the dielectric barrier discharge lamp.
By providing the high frequency lighting circuit for lighting the dielectric barrier discharge lamp, it is possible to provide an ultraviolet irradiation device having the effects of claims 1 to 3.

[Brief description of the drawings]

FIG. 1 is a partial sectional front view showing a first embodiment of a dielectric barrier discharge lamp according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the same.

FIG. 3 is an enlarged longitudinal sectional view of a main part of the same.

FIG. 4 is a partial cross-sectional front view showing the same arc tube.

FIG. 5 is an enlarged sectional view of an essential part of the dielectric barrier discharge lamp, also schematically showing a state of the dielectric barrier discharge.

FIG. 6 is an enlarged sectional view of an essential part of a dielectric barrier discharge lamp according to a second embodiment of the present invention, schematically showing a state of the dielectric barrier discharge in the second embodiment;

FIG. 7 is a front view showing an arc tube and a reflector in a third embodiment of the dielectric barrier discharge lamp of the present invention.

FIG. 8 is a partially omitted cross-sectional view showing a fourth embodiment of the dielectric barrier discharge lamp of the present invention.

FIG. 9 is a sectional view of an essential part showing an ultraviolet cleaning device as a first embodiment of the ultraviolet irradiation device of the present invention.

FIG. 10 is a cross-sectional view of a main part showing an ultraviolet cleaning device as a second embodiment of the ultraviolet irradiation device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Airtight container 1a ... Hollow part 1b ... Sealing part 1b1 ... Molybdenum foil 2 ... Internal electrode 2a ... Connection part 2b ... Unit mesh part 3 ... External electrode 3a ... Unit mesh part 5 ... Slender tube 6 ... Protection tube 7 ... Insulation Base 8: Base terminal 9: Insulated wire 10: Socket 11: Connection terminal B1: First base B2: Second base LT: Arc tube OT: Outer tube R: Reflector WH: Wire harness

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyoshi Nishimura 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Litec Corporation (72) Inventor Ryohiko Tauchi 5-2-2 Asahicho, Imabari City, Ehime Prefecture Within 1 Harrison Toshiba Lighting Co., Ltd. (72) Inventor Toshio Honda Inside 1 Harrison Toshiba Lighting Co., Ltd. 5-2-2 Asahicho, Imabari City, Ehime Prefecture

Claims (4)

[Claims] 1. An elongated tubular hermetic container made of a material that transmits ultraviolet light, an internal electrode sealed in the hermetic container and extending in the axial direction of the hermetic container, an excimer product gas sealed in the hermetic container, and hermetic seal. An arc tube provided with an external electrode disposed on the outer surface of the container; an elongated tubular outer tube accommodating the arc tube; an ultraviolet reflective reflector disposed in the outer tube along a longitudinal direction thereof; A dielectric barrier discharge lamp, comprising: 2. The luminous tube comprises a mesh-like electrode comprising a plurality of turns of a coil wound around the outer electrode of the luminous vessel in contact with the outer surface of the hermetic container; and the reflector comprises an ultraviolet-reflective conductive material. 2. The dielectric barrier discharge lamp according to claim 1, wherein the dielectric barrier discharge lamp is disposed in contact with a plurality of turns of a coil constituting an external electrode. 3. The internal electrode is provided with a unit mesh portion composed of a plurality of ring-shaped portions dispersedly mounted on a connecting portion extending substantially along the axis of the airtight container, and has a mesh shape. The dielectric barrier discharge lamp according to claim 1 or 2, wherein 4. A dielectric barrier discharge lamp according to any one of claims 1 to 3, and an ultraviolet irradiation device main body in which the dielectric barrier discharge lamp is disposed so as to support the reflection plate side thereof. An ultraviolet irradiation device, characterized in that: