JP6831268B2 - Discharge lamp - Google Patents

Description

The present invention relates to a discharge lamp such as an excimer lamp, and more particularly to a configuration of a discharge lamp that generates active oxygen such as ozone.

In excimer lamps, external electrode type fluorescent lamps, etc., a rare gas or the like is sealed in the discharge space of the arc tube (discharge tube), while electrode pairs are arranged on the outer surface of the arc tube. By applying a voltage between the electrodes, a dielectric barrier discharge or a capacitively coupled high frequency discharge occurs, and ultraviolet rays are radiated from the discharge container to the outside of the lamp.

Ozone (O ₃ ) generated by absorption of ultraviolet rays into oxygen (O ₂ ) is a type of active oxygen with high sterilizing ability (oxidizing power), and an excima lamp is used as a light source for deodorizing devices, sterilizing / sterilizing devices, etc. be able to. Further, when ozone is irradiated with ultraviolet rays in a specific wavelength range, atomic or molecular oxygen in an excited state (hereinafter, referred to as excited oxygen) such as a singlet oxygen atom (O) is generated. Excited state oxygen has a very high oxidation promoting function, and can be used for deodorization, sterilization, sterilization, substrate cleaning, surface modification, and the like.

For example, in a water treatment device that sterilizes or disinfects water, a first lamp that radiates ultraviolet rays in the wavelength range of 120 to 190 nm and a second lamp that radiates ultraviolet rays in the wavelength range of 200 to 240 nm cause inflow of water. It is placed in a container that can be taken out. As a result, active oxygen atoms having more excellent oxidizing power are generated together with ozone (see Patent Document 1).

Japanese Unexamined Patent Publication No. 6-21286

When ozone and excited state oxygen are generated using two lamps, the unit structure is such that the two lamps are housed in a container, which complicates the lamp configuration. Further, since the two lamps are arranged in the discharge container, it is difficult to effectively generate ozone and excited state oxygen in a desired amount or a desired region.

Therefore, there is a need for a lamp configuration that effectively generates ozone and excited state oxygen and acts on the object with a simple configuration.

The discharge lamp of the present invention can be applied as, for example, an excimer lamp, and includes a light emitting tube in which a discharge gas is sealed to form a discharge space, and a pair of electrodes arranged to face each other with the light emitting tube interposed therebetween. The arc tube can have a single tube or a double tube structure, and a pair of electrodes are installed on the outer surface of the arc tube, the inner wall of the tube, or the like according to the structure of the arc tube.

Further, the discharge lamp of the present invention includes a phosphor coated on at least a part of the surface of the arc tube exposed to the discharge space. Then, the discharge lamp radiates the first ultraviolet ray having a wavelength range corresponding to the light absorption wavelength range of oxygen to the outside of the arc tube, and the phosphor is excited by the irradiation of the first ultraviolet ray to enter the light absorption wavelength range of ozone. A second ultraviolet ray having a corresponding wavelength range is emitted from the phosphor to the outside of the arc tube.

It is possible to apply the phosphor to the surface of the arc tube so that the first and second ultraviolet rays are emitted from the same radiation surface region of the arc tube. For example, at least a part of the first ultraviolet light is transmitted to the outside of the arc tube through the phosphor.

Alternatively, it is possible to form a phosphor on the surface of the arc tube so that the first ultraviolet light and the second ultraviolet light are emitted from different radiation surface regions, respectively. For example, at least a part of the first ultraviolet light is transmitted to the outside of the arc tube through the surface of the arc tube exposed to the discharge space without transmitting through the phosphor. In this case, the radial surface region can be configured to be bisected along the axial direction. Alternatively, the phosphor is composed of a first ultraviolet ray transmitting portion having a thickness that allows the first ultraviolet ray to be transmitted and a second ultraviolet ray transmitting portion having a thickness that does not transmit the first ultraviolet ray.

The discharge lamp according to another aspect of the present invention includes an arc tube in which a discharge gas is sealed to form a discharge space, and a pair of electrodes arranged to face each other with the arc tube interposed therebetween, and is in the light absorption wavelength range of oxygen. The first ultraviolet ray having the corresponding wavelength range is radiated to the outside of the arc tube, and the second ultraviolet ray having the wavelength range corresponding to the light absorption wavelength range of ozone is radiated to the outside of the arc tube.

In another aspect of the present invention, in the method for generating active oxygen, a pair of electrodes are arranged facing each other with an arc tube in which a discharge gas is sealed, and fluorescence is applied to at least a part of the surface of the arc tube exposed to the discharge space. By forming a body and applying a voltage to a pair of electrodes, first ultraviolet rays having a wavelength range corresponding to the light absorption wavelength range of oxygen are emitted to the outside of the arc tube, and the phosphor is emitted by the first ultraviolet irradiation. By exciting, second ultraviolet rays having a wavelength range corresponding to the light absorption wavelength range of ozone are radiated from the phosphor to the outside of the arc tube, ozone is generated by the first ultraviolet rays, and excited state oxygen is generated by the second ultraviolet rays. Generate.

The reaction generation method in another aspect of the present invention is to irradiate the first ultraviolet ray radiated to the outside of the arc tube by applying a voltage to a pair of electrodes arranged opposite to each other with the arc tube interposed therebetween. The generated first product is characterized in that the second product is produced by irradiating the generated first product with a second ultraviolet ray radiated to the outside of the arc tube.

According to the present invention, in a discharge lamp, ozone and excited state oxygen can be effectively generated and act on an object.

It is the schematic sectional drawing of the discharge lamp which is 1st Embodiment. It is the schematic sectional drawing of the discharge lamp in the 2nd Embodiment. It is the schematic sectional drawing of the discharge lamp in the 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of the discharge lamp according to the first embodiment.

Here, the discharge lamp 10 is an excimer lamp including an arc lamp (discharge tube) 11, an inner electrode 30, and an outer electrode 40, and can be used as a light source for sterilization, sterilization, and deodorization. The arc tube 11 is a discharge tube having a double tube structure including a bottomed tubular outer tube 20 and an inner tube 50 made of a dielectric material such as quartz glass, and is integrally welded at the sealing portion 53. The discharge space S is formed. A rare gas such as xenon gas or a mixed gas thereof is sealed in the discharge space S as a discharge gas. The filling pressure of the discharge gas is set to, for example, 5 kPa to 150 kPa.

A phosphor film C (film) is applied to the surface of the arc tube 11 over substantially the entire surface. More specifically, the inner surface of the outer tube 20 (the inner peripheral surface of the cylindrical portion of the outer tube 20) 20I and the outer surface of the inner tube 50 (the outer peripheral surface of the cylindrical portion of the inner tube 50) 50S are fluorescent. Body C is applied as a film. Further, the phosphor C is composed of a phosphor C1 coated on the inner surface 20I of the outer tube 20 and a phosphor C2 coated on the outer surface 50S of the inner tube 50, and has a substantially uniform thickness.

Regarding the application of the phosphor C, for example, a phosphor introduction tube is provided at both ends of the outer tube 20, one introduction tube is put into a viscous phosphor solution, and the phosphor C is sucked up and discharged from the other introduction tube. As a result, the phosphor C can be applied to the surface of the arc tube 11. Alternatively, the phosphor C may be applied in advance to the inner surface 20I of the outer tube 20 and the outer surface 50S of the inner tube 50, and then the arc tube 11 having a double tube structure may be formed.

Inside the inner tube 50, a band-shaped inner electrode 30 made of a metal foil extending along the axial direction of the discharge lamp 10 is arranged. The inner electrode 30 is covered with an inner tube 50 which is a dielectric material without being exposed to the discharge space S. The feeder line 70 connected to the end of the inner electrode 30 is connected to a power supply unit (not shown) installed outside, and power is supplied to the discharge lamp 10 via the feeder line 70.

The outer electrode 40 is composed of a mesh-like or spiral conductive member so as to transmit light radiated from the discharge space S, is not exposed to the discharge space S, and is a dielectric material so as to face the inner electrode 30 in the radial direction. It is arranged in the axial direction along the outer surface 20S of the outer tube 20.

The polarities of the inner electrode 30 and the outer electrode 40 are set to the anode and the cathode, respectively, and are arranged so as to face each other with the arc tube 11 which is a dielectric interposed therebetween. When a voltage of several kV is applied to the discharge lamp 10, a dielectric barrier discharge occurs between the inner electrode 30 and the outer electrode 40, and ultraviolet rays having a wavelength of 172 nm are radiated as excimer light. The film thickness of the phosphor C is such that ultraviolet rays having a wavelength of 172 nm can be transmitted, and at least a part of the ultraviolet rays having a wavelength of 172 nm is transmitted to the outside of the lamp through the phosphor C.

Oxygen (O ₂ ) in air has a light absorption spectrum in the wavelength range of 100 nm to 240 nm. Therefore, oxygen (O ₂ ) outside the lamp absorbs ultraviolet rays (first ultraviolet rays) having a wavelength of 172 nm radiated from the discharge lamp 10, and undergoes photodecomposition of two oxygen atoms (O) to ozone molecules (O ₃ ). (First product) is produced.

On the other hand, when the phosphor C (second ultraviolet emitting part) receives ultraviolet rays having a wavelength of 172 nm, it emits fluorescence having a wavelength of 250 nm (second ultraviolet rays), whereby the ultraviolet rays having a wavelength of 250 nm are emitted from the phosphor C to the outside of the lamp. To. Ozone molecules _{(O 3),} have a light absorption spectrum in the wavelength range of 200- 300nm. Therefore, the ozone generated by ultraviolet irradiation of wavelength 172 nm _{(O 3)} absorbs ultraviolet radiation wavelength 250nm to the lamp outside.

As a result, excited state oxygen (second product) such as singlet oxygen atoms and singlet oxygen molecules in the excited state having higher energy than the ground state is generated outside the lamp. Excited state oxygen is active oxygen in a very highly active state, and can perform actions such as deodorization, bleaching, sterilization, and surface oxidation on an object.

As described above, in the present embodiment, in the discharge lamp 10 provided with the arc tube 11 having a double tube structure, the wavelength is relative to the surface of the arc tube 11 (the outer surface 50S of the inner tube 50 and the inner surface 20I of the outer tube 20). The phosphor C, which receives ultraviolet rays of 172 nm and emits fluorescence having a wavelength of 250 nm, is thinly coated over the entire surface with a substantially uniform thickness. As a result, ultraviolet rays having wavelengths of 172 nm and 250 nm are both emitted from the entire outer surface 20S of the outer tube 20 which is the radiation surface of the arc tube 11. By radiating two ultraviolet rays from the same radiation surface region, both ozone and excited state oxygen can be generated as active oxygen.

The discharge lamp may radiate ultraviolet rays having a wavelength other than 172 nm, and may be ultraviolet rays in the range of the light absorption spectrum of oxygen (O ₂ ) (wavelength range of about 100 nm to 240 nm). Further, even in the phosphor C, excited by ultraviolet radiation due to discharge, wavelength than ultraviolet due to discharge is long, emits ultraviolet light in ozone (wavelength range of approximately 200- 300nm) range of the light absorption spectra of (O ₃₎ It may be configured as follows. Further, it is also possible to configure either the inner surface 20I of the outer tube 20 or the outer surface 50S of the inner tube 50 without applying a phosphor.

Next, the discharge lamp according to the second embodiment will be described with reference to FIG. In the second embodiment, ultraviolet rays having a wavelength of 172 nm and ultraviolet rays having a wavelength of 250 nm are emitted from different radiation surface regions. Other than that, it is substantially the same as the first embodiment.

FIG. 2 is a schematic cross-sectional view of the discharge lamp according to the second embodiment.

The phosphor C'is applied only to the surface region facing the outer surface (radiating surface region) 20A of the left half of the outer tube 20, and is applied to the surface region facing the outer surface 20B of the right half of the outer tube 20. Not applied. The phosphor C'is composed of a phosphor C'1 coated on the inner surface 20I of the outer tube 20 and a phosphor C'2 coated on the outer surface 50S of the inner tube 50.

Further, the phosphor C'is not in the form of a thin film as in the first embodiment, but has a thickness that does not allow ultraviolet rays having a wavelength of 172 nm to pass through. Therefore, the ultraviolet rays having a wavelength of 172 nm radiate from the radiation surface region 20B to the outside of the lamp, while the ultraviolet rays having a wavelength of 250 nm radiate from the radiation surface region 20A to the outside of the lamp.

By selectively radiating ultraviolet rays having a wavelength of 172 nm and ultraviolet rays having a wavelength of 250 nm in the radiation surface region in this way, it is possible to adjust the balance between the amount of ozone and the amount of oxygen in the excited state. Here, the radiation surface region of the arc tube 11 is substantially bisected along the axial direction, but the ratio can be adjusted by adjusting the axial length to which the phosphor C'is applied. it can. For example, in the method of sucking up from the fluorescent liquid surface, the coating range along the axial direction of the phosphor C can be adjusted by adjusting the sucking height.

Next, the discharge lamp according to the third embodiment will be described with reference to FIG. In the third embodiment, a radiation surface region that emits ultraviolet rays having a wavelength of 172 nm and a radiation surface region that emits ultraviolet rays having a wavelength of 250 nm are divided into a plurality of parts.

FIG. 3 is a schematic cross-sectional view of the discharge lamp according to the third embodiment.

The fluorescent substance C "is entirely applied in the arc tube 11 as in the first embodiment. On the other hand, the thickness of the fluorescent substance C" is not constant and is a thin film-like portion (thin portion). It is composed of CA and CB, and thicker portions (thick portions) C1, C2, and C3. The thin portions CA and CB and the thick portions C1, C2 and C3 are formed alternately along the axial direction.

By applying the phosphor C "into the arc tube 11 in this way, it is possible to radiate ultraviolet rays having a wavelength of 172 nm and ultraviolet rays having a wavelength of 250 nm from the radiation surface regions arranged alternately. That is, the thin portion CA, While ultraviolet rays having a wavelength of 172 nm are radiated from the CB to the outside of the lamp, ultraviolet rays having a wavelength of 172 nm are not transmitted from the thick portions C1, C2, and C3, so only ultraviolet rays having a wavelength of 250 nm are radiated from the phosphor C "outside the lamp. The coating of the phosphor C "can be formed as shown in FIG. 3 by gradually changing the rate of lowering the phosphor liquid level in, for example, a suction method from the phosphor liquid level. The slower the coating, the thicker the coating, and the faster the speed, the thinner the coating.

In the first to third embodiments, the arc tube having a double tube structure is applied, but a single tube type arc tube may be used. It can also be applied to discharge lamps other than excimer lamps.

The phosphor may be configured to contain a fluorescent substance inside the arc tube, instead of being applied to the surface of the arc tube. In addition, using photoluminescence, a wavelength conversion means (film) using a substance that emits light in an excited state by light is formed inside the arc tube or on the surface of the arc tube, and ultraviolet rays absorbed by ozone are radiated to the outside of the lamp. It may be configured to cause. Further, the wavelength of ultraviolet rays (discharge gas) of the discharge lamp and the wavelength conversion means (film) such as a phosphor may be selected so as to sequentially generate active oxygen other than ozone and excited state oxygen.

10 Discharge lamp 11 Light emitting tube 20 Outer tube 30 Inner electrode 40 Outer electrode 50 Inner tube C Fluorescent material

Claims (10)

An arc tube that is filled with discharge gas to form a discharge space,
A pair of electrodes arranged to face each other with the arc tube interposed therebetween,
A phosphor coated on at least a part of the arc tube surface exposed to the discharge space is provided.
The first ultraviolet ray having a wavelength range corresponding to the light absorption wavelength range of oxygen is radiated to the outside of the arc tube.
A discharge characterized by radiating a second ultraviolet ray having a wavelength range corresponding to the light absorption wavelength range of ozone from the phosphor to the outside of the arc tube by exciting the phosphor by irradiation with the first ultraviolet ray. lamp. The discharge lamp according to claim 1, wherein the first ultraviolet ray and the second ultraviolet ray are emitted from the same radiation surface region of the arc tube. The discharge lamp according to claim 1 or 2, wherein at least a part of the first ultraviolet rays passes through the phosphor and radiates to the outside of the arc tube. The discharge lamp according to claim 1, wherein the first ultraviolet ray and the second ultraviolet ray are emitted from different radiation surface regions, respectively. The discharge lamp according to claim 4, wherein at least a part of the first ultraviolet rays passes through the surface of the arc tube exposed to the discharge space without transmitting through the phosphor and is radiated to the outside of the arc tube. .. The discharge lamp according to claim 4 or 5, wherein the radiation surface region is divided into two along the axial direction. The fourth aspect of claim 4, wherein the phosphor has a first ultraviolet ray transmitting portion having a thickness that allows the first ultraviolet ray to pass through, and a second ultraviolet ray transmitting portion having a thickness that does not allow the first ultraviolet ray to pass through. Discharge lamp. An arc tube that is filled with discharge gas to form a discharge space,
A pair of electrodes arranged to face each other with the arc tube interposed therebetween.
The first ultraviolet ray having a wavelength range corresponding to the light absorption wavelength range of oxygen is radiated to the outside of the arc tube.
A discharge lamp characterized in that when the first ultraviolet ray is irradiated to the second ultraviolet ray emitting portion, the second ultraviolet ray having a wavelength range corresponding to the light absorption wavelength range of ozone is emitted to the outside of the arc tube. A pair of electrodes are placed facing each other with an arc tube in which the discharge gas is sealed to form a discharge space.
A phosphor is formed on at least a part of the surface of the arc tube exposed to the discharge space.
By applying a voltage to the pair of electrodes, first ultraviolet rays having a wavelength range corresponding to the light absorption wavelength range of oxygen are radiated to the outside of the arc tube.
By exciting the phosphor by irradiation with the first ultraviolet ray, the second ultraviolet ray having a wavelength range corresponding to the light absorption wavelength range of ozone is radiated from the phosphor to the outside of the arc tube.
A method for producing active oxygen, in which ozone is generated by the first ultraviolet ray and excited state oxygen is generated by the second ultraviolet ray. By applying a voltage to a pair of electrodes arranged opposite to each other with an arc tube interposed therebetween,
With respect to the first product produced by irradiating the first ultraviolet ray radiated to the outside of the arc tube.
A reaction generation method by ultraviolet irradiation, which comprises producing a second product by irradiating the second ultraviolet ray radiated to the outside of the arc tube.

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