JP2000193799A - Ultraviolet-ray irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet-ray irradiation device which makes it possible to securely verify whether a dielectric barrier discharge lamp lights up or not and, what is more, has a simple structure and enables easy maintenance in an ultraviolet-ray irradiation device equipped with a dielectric barrier discharge lamp. SOLUTION: This irradiation device is equipped with a casing 10 with a window part 15 for detecting light, a dielectric barrier discharge lamp 30 that is encased in the easing 10 and emits ultraviolet rays by generating excimer in a discharge container 31 through dielectric barrier discharge and a photo sensor 25 for detecting a visible ray which penetrates the window part 15 for detecting light in the casing 10. Phosphors 40 that receive the ultraviolet rays emitted from the discharge container 31 and emit a visible ray are provided in the dielectric barrier discharge lamp 30, so that the visible ray can penetrate the window part 15 for detecting light in the casing 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet irradiation device having a dielectric barrier discharge lamp.

[0002]

2. Description of the Related Art In recent years, an object to be processed made of metal, glass, or another material is irradiated with vacuum ultraviolet rays having a wavelength of 200 nm or less, and the object to be processed is processed by the action of the vacuum ultraviolet rays and ozone generated thereby. Technology
For example, a cleaning treatment technique for removing organic contaminants attached to the surface of the treatment object and an oxide film formation treatment technique for forming an oxide film on the surface of the treatment object have been developed and have been put to practical use.

A low-pressure mercury lamp that emits vacuum ultraviolet light having a wavelength of 185 nm, which is a resonance line of mercury, has been used as a lamp for performing such ultraviolet treatment. An appropriate excimer emission gas is filled in a discharge vessel constituted by a body, and a dielectric barrier discharge (also known as "ozonizer discharge" or "silent discharge") is issued in the discharge vessel. June 2001 Reprint, 7th edition second
See page 63. ), A dielectric barrier discharge lamp has been developed in which excimer is generated and excimer light is emitted. For example, Japanese Patent Application Laid-Open No. 1-144560
Japanese Patent Laid-Open Publication No. H11-15764 discloses a dielectric barrier discharge lamp in which a gas for excimer light emission is filled in a hollow cylindrical discharge vessel made of quartz glass, at least part of which is a dielectric.

In this dielectric barrier discharge lamp,
By using, for example, xenon gas as the gas for excimer light emission, vacuum ultraviolet rays having a peak at a wavelength of 172 nm, which is excimer light by xenon excimer, are emitted, and a mixed gas of, for example, argon and chlorine gas is used as the gas for excimer light emission. In this way, argon-
It is known that vacuum ultraviolet light having a peak at a wavelength of 175 nm, which is excimer light due to chlorine excimer, is emitted.

However, when the dielectric barrier discharge lamp is lit in air, the dielectric barrier discharge lamp is caused by vacuum ultraviolet rays from the dielectric barrier discharge lamp or corona discharge generated at the electrodes of the dielectric barrier discharge lamp. Since oxygen in the air around the body barrier discharge lamp reacts to generate ozone, there is a problem that the electrode is corroded by the generated ozone when used for a long time.
In addition, since the vacuum ultraviolet rays from the dielectric barrier discharge lamp are absorbed by oxygen in the air, there is a problem that the object to be processed cannot be irradiated with the vacuum ultraviolet rays with high efficiency. For this reason, when using the dielectric barrier discharge lamp, the dielectric barrier discharge lamp is housed and arranged in a casing having a window for extracting excimer light, thereby constituting an ultraviolet irradiation device. By introducing an inert gas such as nitrogen gas into the casing of the ultraviolet irradiation device, the interior of the casing is set to an inert gas atmosphere, and in this state, the dielectric barrier discharge lamp of the ultraviolet irradiation device is turned on. Has been done.

In such an ultraviolet irradiation apparatus, it is not possible to visually check whether the dielectric barrier discharge lamp housed in the casing is on or not. Lighting confirmation means for confirming the lighting of the lamp is provided. As such lighting confirmation means, conventionally, means for confirming the lighting of the dielectric barrier discharge lamp by detecting the lamp current has been used. However, in such lighting confirmation means, the lamp current is detected even when a discharge abnormality occurs due to slow leak or generation of impurity gas in the discharge vessel, so that the lighting state is abnormal. Cannot be confirmed.

In order to solve the above-mentioned problems, recently, as a lighting confirmation means, a photodetector comprising a phosphor which receives ultraviolet rays and emits a visible ray and a photoelectric element has been used, and a light from a dielectric barrier discharge lamp has been used. Means for confirming lighting of the dielectric barrier discharge lamp by converting ultraviolet light into visible light with a phosphor and detecting the visible light with a photodiode is employed.

FIG. 8 is an explanatory diagram showing the configuration of an example of an ultraviolet irradiation device having such a photodetector. In this figure, reference numeral 80 denotes a box-shaped casing, in which a dielectric barrier discharge lamp 85 is housed. Reference numeral 81 denotes a light extraction window for extracting ultraviolet light from the dielectric barrier discharge lamp 85;
Denotes a light detection through-hole 82 for detecting ultraviolet light from the dielectric barrier discharge lamp 85. Numeral 90 denotes a photodetector for detecting ultraviolet rays from the dielectric barrier discharge lamp 85, in which a support plate 91 made of, for example, synthetic quartz glass, and a phosphor layer formed on the support plate 91 are provided. A fluorescent member 94 composed of 92 and a protective plate 93 made of soda glass provided on the phosphor layer 92 is disposed, and a photoelectric element 95 composed of a silicon photodiode is disposed above the fluorescent member 94. ing.

In such an ultraviolet irradiation device, the phosphor layer 92 of the fluorescent member 94 in the photodetector 90 receives ultraviolet rays from the dielectric barrier discharge lamp 85, so that visible light is emitted from the phosphor layer 92. The visible light is detected by the photoelectric element 95,
Lighting of the dielectric barrier discharge lamp 85 is confirmed.

However, the above-mentioned ultraviolet irradiation apparatus has the following problems. (1) In order to irradiate the phosphor with ultraviolet rays from the dielectric barrier discharge lamp, it is necessary to make the interior of the photodetector not only the casing but also the atmosphere of the inert gas, so that the configuration of the entire apparatus is complicated. It becomes something. (2) Since the quartz plate and the phosphor in the photodetector are deteriorated by receiving ultraviolet rays from the dielectric barrier discharge lamp, they need to be replaced each time a certain use time elapses. In addition, since it is necessary to manage each of the usage time of the dielectric barrier discharge lamp, the usage time of the quartz plate, and the usage time of the phosphor, maintenance of the entire apparatus becomes complicated.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made based on the above circumstances, and its object is to provide:
In an ultraviolet irradiation device equipped with a dielectric barrier discharge lamp, it is possible to reliably confirm whether or not the dielectric barrier discharge lamp is lit, and has a simple structure, and is easy to maintain. It is to provide a device.

[0012]

According to the present invention, there is provided an ultraviolet irradiation apparatus comprising: a casing having a photodetection window; and an excimer generated in a discharge vessel by a dielectric barrier discharge housed in the casing. And a photodetector for detecting visible light transmitted through the light detection window of the casing, wherein the dielectric barrier discharge lamp includes the discharge vessel. A phosphor that emits visible light in response to ultraviolet light emitted from the inside is provided so that the visible light passes through the light detection window of the casing.

In the ultraviolet irradiation apparatus of the present invention, the discharge vessel of the dielectric barrier discharge lamp has one cylindrical wall and the other cylindrical wall having an outer diameter smaller than the inner diameter of the one wall. When the phosphor has a hollow cylindrical shape having a wall portion, the phosphor may be provided on an outer surface side of one wall portion. Further, the discharge vessel in the dielectric barrier discharge lamp has a hollow cylindrical shape having one cylindrical wall and the other cylindrical wall having an outer diameter smaller than the inner diameter of the one wall. In the case of having the phosphor, the phosphor may be provided on the outer surface side of the other wall.

[0014]

According to the above-mentioned ultraviolet irradiation apparatus, the ultraviolet light emitted from the discharge vessel of the dielectric barrier discharge lamp is converted into visible light by the fluorescent substance, and this visible light is detected by the photodetector. The lighting of the barrier discharge lamp can be reliably confirmed. In addition, since the photodetector detects visible light, it is not necessary to set the inside of the photodetector to an inert gas atmosphere, and as a result, the entire apparatus has a simple structure. Further, since the fluorescent material is provided in the dielectric barrier discharge lamp, the fluorescent material is replaced at the same time by replacing the dielectric barrier discharge lamp with a new one, so that the maintenance of the entire apparatus is easy.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the ultraviolet irradiation apparatus of the present invention will be described in detail. FIG. 1 is an explanatory sectional view showing the configuration of an example of the ultraviolet irradiation device of the present invention. In this ultraviolet irradiation apparatus, four dielectric barrier discharge lamps 30 each having a hollow cylindrical discharge vessel 31 are housed in a casing 10 made of a rectangular box-shaped stainless steel as a whole.

In the casing 10, an opening 1 is provided on the lower surface.
A rectangular box-shaped frame member 11 having a dielectric barrier discharge lamp 3 is provided in an opening 12 of the frame member 11.
A light extraction window 13 for extracting vacuum ultraviolet rays from 0 to the outside is arranged. As a material for forming the light extraction window 13, a material having transparency to vacuum ultraviolet rays from the dielectric barrier discharge lamp 10, for example, synthetic quartz glass can be used. On the upper surface of the frame material 11,
The through-hole 14 is provided above the dielectric barrier discharge lamp 30.
The through hole 14 is provided with a light detection window 15 that transmits visible light. As a material for forming the light detection window 15, a material having transparency to visible light, for example, borosilicate glass can be used. Also, on one side surface of the frame material 11, a casing 10
A gas introduction hole 16 for introducing an inert gas is formed therein, and a gas discharge hole 17 for discharging gas in the casing 10 is formed on the other side surface of the frame member 11.

A cooling block 20 made of aluminum is provided at an upper portion in the casing 10. On the lower surface of the cooling block 20, four grooves 21 each having a semicircular cross section having a diameter larger than the outer diameter of the dielectric barrier discharge lamp 30 are formed so as to be spaced apart from each other. A dielectric barrier discharge lamp 30 is arranged along each of the above. In the cooling block 20, a light-introducing hole 2 that penetrates the cooling block 20 in the vertical direction and passes through the groove 21 is provided at a position immediately below the light detection window 15.
2 are formed. Reference numeral 23 denotes a cooling fluid flow passage formed to penetrate the cooling block 20 and flow the cooling fluid.

Light detection window 15 in casing 10
A photodetector 25 having a photoelectric element 26 is provided on the upper surface of the photodetector 25. Specifically, the photodetector 25 is arranged such that the light receiving portion 27 of the photoelectric element 26 faces the dielectric barrier discharge lamp 30 through the light detection window 15 and the light introduction hole 22 of the cooling block 20. I have. As the photoelectric element 26, a silicon photodiode or the like can be used.

In the dielectric barrier discharge lamp 30,
As shown in FIG. 2, a hollow cylindrical discharge vessel 31 is provided. More specifically, the discharge vessel 31
Is one of a cylindrical wall portion 32 made of a dielectric and a dielectric member disposed inside the one wall portion 32 along the cylinder axis and having an outer diameter smaller than the inner diameter of the one wall portion 32. And both ends of the one wall portion 32 and the other wall portion 33 are joined by a sealing wall portion 34, and the one wall portion 32 and the other wall portion 33 are formed. A cylindrical discharge space S is formed between the discharge space S and the wall 33. The discharge vessel 31 is filled with an excimer emission gas.

One wall portion 32 of the discharge vessel 31 is provided with one ultraviolet-transparent electrode 36 made of a conductive material such as a wire mesh in close contact with an outer surface 35 of the discharge vessel 31. The wall 33 is provided with another plate-shaped electrode 38 made of aluminum so as to cover an outer surface 37 which is an inner peripheral surface thereof.

In the example shown in the figure, a deformed portion 39 is formed at one end of one wall portion 32 of the discharge vessel 31 so as to protrude inward in the circumferential direction.
A getter accommodating chamber K communicating with the discharge space S is formed between the deformed portion 39 and the sealing wall 34 on one end side, and a getter G made of, for example, a barium alloy is accommodated in the getter accommodating chamber K. I have. The getter G is heated by, for example, high frequency, so that a thin film made of barium is formed on the inner wall surface of the getter accommodating chamber K.

As the dielectric material constituting the discharge vessel 31, a material having transparency to excimer light emitted in the discharge vessel 11, for example, synthetic quartz glass can be used. As the gas for excimer emission sealed in the discharge vessel 11, a gas that generates excimer that emits excimer light with a wavelength of 200 nm or less, for example, a xenon gas or a mixed gas of argon and chlorine can be used.

On the outer surface of one wall portion 32 of the discharge vessel 31 of the dielectric barrier discharge lamp 30, the light is discharged from the discharge vessel 31 to a position directly below the light detection window 15 of the casing 10. A phosphor layer 40 that receives visible light and emits visible light is formed. As the phosphor constituting the phosphor layer 40, sodium salicylate, zinc silicate manganese (Zn ₂ SiO ₄ Mn), or the like can be used. The means for forming the phosphor layer 40 is not particularly limited. For example, a coating solution containing a phosphor is prepared, and this coating solution is applied to the phosphor layer 40.
Can be used to apply and sinter at the place where the is to be formed.

In the above-described ultraviolet irradiation apparatus, an inert gas such as nitrogen gas is introduced from the gas inlet 16 of the casing 10 and the gas inside the casing 10 is discharged from the gas outlet 17 so that 10
The inside is an inert gas atmosphere. In the dielectric barrier discharge lamp 30, when a voltage is applied between the one electrode 36 and the other electrode 38, a dielectric barrier discharge occurs in the discharge space S in the discharge vessel 31, As a result, an excimer due to the elements constituting the excimer emission gas is generated, and excimer light generated by the excimer is emitted from the mesh of the one electrode 36 through the one wall 32, and the excimer light is extracted from the casing 10. The object to be processed, which is arranged directly below the light extraction window 13, is irradiated via the window 13. On the other hand, the phosphor layer 40 provided in the dielectric barrier discharge lamp 30 has a discharge space S
Emits visible light by receiving ultraviolet light from
This visible light is detected by the photodetector through the light introduction hole 22 of the cooling block 20 and the light detection window 15, and thereby the lighting of the dielectric barrier discharge lamp is confirmed.

An example of the specification of the ultraviolet irradiation apparatus of the present invention is as follows. Casing 10: Dimensions: 490 mm × 360 mm × 70 mm, light extraction window 13; synthetic quartz glass, thickness 3 mm, light detection window 15; hard glass, thickness 2 mm, dielectric barrier discharge lamp 30: discharge vessel 31 Effective length 300 mm, one wall part 32; made of synthetic quartz glass, outer diameter 26 mm, wall thickness 1 mm, the other wall part 33; made of synthetic quartz glass, outer diameter 16 mm, wall thickness 1 mm, one electrode 36; Electrode 38; aluminum, excimer emission gas; xenon gas (peak wavelength of emitted ultraviolet rays 172 nm); rated power: 50 W; phosphor layer 40: material; zinc silicate manganese (Zn)
₂ SiO ₄ Mn), thickness 20 μm

According to the ultraviolet irradiation apparatus as described above, the ultraviolet light emitted from inside the discharge vessel 31 of the dielectric barrier discharge lamp 30 is converted into visible light by the phosphor layer 40,
Since this visible light is detected by the photodetector 25, the lighting of the dielectric barrier discharge lamp 30 can be reliably confirmed. Further, since the photodetector 25 detects visible light, it is not necessary to make the inside of the photodetector 25 an inert gas atmosphere, and as a result, the entire apparatus has a simple structure. Further, since the phosphor layer 40 is formed on the outer surface of the discharge vessel 31 of the dielectric barrier discharge lamp 30, by replacing the dielectric barrier discharge lamp 30 with a new one, the phosphor layer 40 is also replaced at the same time. So
Maintenance of the entire device is easy.

The ultraviolet irradiation device of the present invention is not limited to the above-described embodiment, and various changes can be made. (1) If the position where the phosphor layer 40 is provided is a position where visible light emitted from the phosphor layer 40 passes through the light detection window 15 of the casing 10, one wall portion of the discharge vessel 31 is provided. It is not limited to 32 outer surfaces.
For example, as shown in FIG. 3, it may be provided between the other wall portion 33 and the other electrode 38. When the phosphor layer 40 is provided at such a position, the phosphor layer 40
May be formed on the outer surface of the other wall portion 33, or may be formed on the inner surface of the other electrode. According to the configuration in which the phosphor layer 40 is formed on the inner surface of the other electrode 38, a complicated process of directly forming the phosphor layer 40 on the discharge vessel 31 can be omitted, and high productivity can be obtained.

(2) The phosphor layer 40 does not need to be formed directly on the surface of the discharge vessel 31. For example, as shown in FIG. 4, the phosphor layer 40 is formed on a support plate 41 made of synthetic quartz glass. To form the fluorescent member 45,
The fluorescent member 45 may be sandwiched between the one wall 32 and the one electrode 36. Further, as shown in FIG. 5, an opening may be formed in the other electrode 38, and a fluorescent member 45 in which the phosphor layer 40 is formed on the support plate 41 may be fixedly disposed in the opening. According to the configuration using the fluorescent member 45 having the phosphor layer 40, a complicated process of directly forming the phosphor layer 40 in the discharge vessel 31 can be omitted, and high productivity can be obtained.

(3) When configuring the fluorescent member 45,
As shown in FIGS. 6 and 7, a protective layer 42 made of, for example, soda glass can be formed on the surface of the phosphor layer 40 formed on a support 41 made of synthetic quartz glass. In the case where such a fluorescent member 45 is provided, the support 41 having transparency to the ultraviolet light from the discharge space S in the discharge vessel 31 is provided on one wall 32 or the other wall of the discharge vessel 31. Is arranged so as to be in contact with the outer surface of the phosphor layer 4.
0 can be irradiated. According to the configuration using such a fluorescent member 45, the phosphor layer 40 is covered with the support 41 and the protective layer 42, so that the phosphor layer 42
Can be prevented from being peeled or damaged.

(4) As the basic structure of the dielectric barrier discharge lamp, various ones can be adopted. For example, a plate-like one made of aluminum is used as one of the electrodes.
A configuration in which ultraviolet rays are extracted from the sealing wall portion 34 in the discharge vessel 31 may be employed.

[0031]

According to the ultraviolet irradiation apparatus of the present invention, since the dielectric barrier discharge lamp is provided with the fluorescent material, the ultraviolet light emitted from the discharge vessel is converted into visible light by the fluorescent material. Visible light can be detected by the photodetector, and therefore, lighting of the dielectric barrier discharge lamp can be reliably confirmed. Also, the photodetector
Since it detects visible light, it is not necessary to set the inside of the photodetector to an inert gas atmosphere, and as a result,
An ultraviolet irradiation device can be configured with a simple structure. Furthermore, since the fluorescent material is provided in the dielectric barrier discharge lamp, the fluorescent material is simultaneously replaced by replacing the dielectric barrier discharge lamp with a new one.
Maintenance of the entire apparatus can be easily performed.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view schematically showing a configuration of an example of an ultraviolet irradiation device of the present invention.

FIG. 2 is an explanatory sectional view showing a configuration of an example of a dielectric barrier discharge lamp used in the ultraviolet irradiation device of the present invention.

FIG. 3 is an explanatory sectional view showing a configuration of another example of the dielectric barrier discharge lamp used in the ultraviolet irradiation device of the present invention.

FIG. 4 is an explanatory sectional view showing the configuration of still another example of the dielectric barrier discharge lamp used in the ultraviolet irradiation device of the present invention.

FIG. 5 is an explanatory sectional view showing a configuration of still another example of the dielectric barrier discharge lamp used in the ultraviolet irradiation device of the present invention.

FIG. 6 is an explanatory cross-sectional view showing the configuration of still another example of the dielectric barrier discharge lamp used in the ultraviolet irradiation device of the present invention.

FIG. 7 is an explanatory sectional view showing the configuration of still another example of the dielectric barrier discharge lamp used in the ultraviolet irradiation device of the present invention.

FIG. 8 is an explanatory sectional view showing a configuration of an example of a conventional ultraviolet irradiation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Casing 11 Frame material 12 Opening 13 Light extraction window part 14 Through hole 15 Light detection window part 16 Gas introduction hole 17 Gas discharge hole 20 Cooling block 21 Groove 22 Light introduction hole 23 Cooling fluid flow passage 25 Photodetector 26 Photoelectric device 27 Light receiving unit 30 Dielectric barrier discharge lamp 31 Discharge vessel 32 One wall 33 Other wall 34 Sealing wall 35 Outer surface of one wall 36 One electrode 37 Outer surface of other wall 38 Other Electrode 39 Deformed part 40 Phosphor layer 41 Support 42 Protective layer 45 Fluorescent member G Getter K Getter storage chamber S Discharge space 80 Casing 81 Light extraction window 82 Light detection through hole 85 Dielectric barrier discharge lamp 90 Photodetector Reference Signs List 91 support 92 phosphor layer 93 protective plate 94 fluorescent member 95 photoelectric element

Claims (3)

[Claims] 1. A casing having a light detection window, a dielectric barrier discharge lamp housed in the casing, wherein excimer is generated in a discharge vessel by dielectric barrier discharge to emit ultraviolet rays, A light detector for detecting visible light transmitted through the light detection window of the casing, wherein the dielectric barrier discharge lamp receives visible light upon receiving ultraviolet rays emitted from the discharge vessel. An ultraviolet irradiation device, wherein the phosphor to be emitted is provided so that the visible light passes through the light detection window of the casing. 2. A discharge vessel in a dielectric barrier discharge lamp has a hollow cylindrical shape having one cylindrical wall and the other cylindrical wall having an outer diameter smaller than the inner diameter of the one wall. The ultraviolet irradiation device according to claim 1, wherein the phosphor is provided on an outer surface side of the one wall portion. 3. A discharge vessel in a dielectric barrier discharge lamp has a hollow cylindrical shape having one cylindrical wall and the other cylindrical wall having an outer diameter smaller than the inner diameter of the one wall. The ultraviolet irradiation device according to claim 1, wherein the phosphor is provided on an outer surface side of the other wall portion.