Ultraviolet irradiation device, ozone generation device, and method for lighting an excimer lamp

Abstract

To provide an excimer lamp capable of effectively irradiating ultraviolet rays in an ozone generator or the like.SOLUTION: An ozone generator 100 includes an excimer lamp 10 and a control unit 110. The control unit 110 repeatedly turns on and off the excimer lamp 10 at a frequency f2 that is lower than the frequency f1 at which a voltage is applied to the excimer lamp 10 such that the discharge in the transient state continues.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an excimer lamp, and particularly to lamp lighting control.

Background Art

[0002] In an excimer lamp, an electrode (hereinafter referred to as an outer electrode) is disposed on the outer peripheral surface of a discharge vessel made of a dielectric such as quartz glass. On the other hand, an electrode (hereinafter referred to as an inner electrode) is disposed along the lamp axis inside the discharge vessel, and a rare gas such as xenon gas is enclosed in the discharge vessel. By applying a voltage between the inner electrode and the outer electrode, dielectric barrier discharge or capacitive coupling type high-frequency discharge occurs in the discharge space in the discharge vessel, and ultraviolet rays are radiated as excimer light (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when an excimer lamp is used in an ozone generator, the required ozone generation amount varies depending on the use environment, use conditions, etc., and stable ozone generation at a low concentration may be required. Also, in a small ozone generator using a battery, etc., there are limitations on the size, power, etc. of the excimer lamp, and ozone generation with suppressed power consumption is required.

[0005] Therefore, lighting control of an excimer lamp capable of effectively irradiating ultraviolet rays is required according to the use environment such as an ozone generator.

Means for Solving the Problems

[0006] An ultraviolet irradiation device according to one aspect of the present invention is applicable to an ozone generation device, and includes an excimer lamp and a control unit that controls lighting of the excimer lamp. Then, the control unit repeats lighting and extinguishing of the excimer lamp so as to continue the discharge in the transient state. As such lighting control, it is possible to make the frequency f2 at which the lighting and extinguishing of the excimer lamp are periodically repeated lower than the frequency f1 of the voltage applied to the excimer lamp. For example, the frequency f2 can be set in the range of 1 to 60 Hz.

[0007] For example, the ozone generation device can be provided with an operation detection switch that detects an input operation by the user. The operation detection switch can be configured to detect the input operation at a period of frequency f3 = f2 × n (n is a natural number).

[0008] An ozone generation device according to another aspect of the present invention includes an excimer lamp and a control unit that controls lighting of the excimer lamp, and the control unit repeats lighting and extinguishing of the excimer lamp so as to continue the discharge in the transient state. For example, it is possible to perform lighting control that repeats lighting and extinguishing so that the amount of ozone generated when repeating the discharge in the transient state is equal to or less than half of the amount of ozone generated in the steady-state discharge.

[0009] The ozone generation device can be provided with a flow path tube that houses the excimer lamp inside. It is possible to perform lighting control so that the flow rate of the fluid containing oxygen flowing through the flow path tube is 1 m 3 / min or less.

[0010] For example, the ozone generation device can be provided with an operation detection switch that detects an input operation by the user. The operation detection switch can be configured to detect the input operation at a period of frequency f3 = f2 × n (n is a natural number).

[0011] Another aspect of the present invention is a method for lighting an excimer lamp, which is a method for lighting an excimer lamp having at least an electrode partially exposed in at least a discharge vessel, and repeats lighting and extinguishing of the excimer lamp so as to continue a transient discharge.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide an excimer lamp that can effectively irradiate ultraviolet rays in an ozone generator or the like.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0014] Hereinafter, with reference to the drawings, an ozone generator including an excimer lamp according to an embodiment of the present invention will be described.

[0015] FIG. 30 is a schematic cross-sectional view of an excimer lamp in an ozone generator according to the present embodiment as viewed from the side.

[0016] The ozone generator 100 includes an excimer lamp 10 and is operationally controlled by a control unit (not shown here). The excimer lamp 10 is disposed in a flow path tube 90 through which a raw material gas containing oxygen flows. While the raw material gas flows around the excimer lamp 10 by an intake fan (not shown), the excimer lamp 10 irradiates the raw material gas with ultraviolet rays to generate ozone.

[0017] The ozone generator 100 is configured here as a low-concentration ozone generator and as a small-sized device driven by a battery. That is, the ozone generator 100 incorporating an ultraviolet irradiation device including an excimer lamp 10 and a control unit capable of controlling the lighting of the excimer lamp 10 can be installed horizontally so that the flow path tube 90 is along the horizontal direction, and can also be installed directly above so that the flow path tube 90 is along the vertical direction.

[0018] The excimer lamp 10 includes a discharge vessel 20 sealed by reduced-diameter portions where the inner diameter of the cross-section surrounding the discharge space region is constant along the lamp axis C at both ends of a substantially cylindrical cylindrical portion and the inner diameter is reduced along the lamp axis C. The excimer lamp 10 is made of a dielectric material such as quartz glass that transmits ultraviolet rays. A small-diameter portion 21 integrally formed via the reduced-diameter portion is formed on the tip side of the cylindrical portion of the discharge vessel 20, and a sealing tube 22 is integrally formed via the reduced-diameter portion on the rear end side. That is, in the discharge vessel 20, the small-diameter portion 21 and the reduced-diameter portion are integrally formed on the tip side of the cylindrical portion, and the sealing tube 22 and the reduced-diameter portion are integrally formed on the rear end side of the cylindrical portion. A rare gas such as xenon is enclosed in the discharge space S in the discharge vessel 20.

[0019] In the sealing tube 22, the inner electrode 40 is arranged so as to extend along the lamp axis C, and its electrode tip portion (hereinafter referred to as the tip portion) 40T is exposed to the discharge space S and faces the cylindrical portion of the discharge vessel 20 along the lamp diameter direction. That is, only the tip portion 40T of the inner electrode 40 faces the cylindrical portion of the discharge vessel 20 along the lamp diameter direction, and the other portions of the inner electrode 40 face the reduced-diameter portion of the discharge vessel 20 along the lamp diameter direction and do not face the cylindrical portion of the discharge vessel 20. On the other hand, the rear end side of the inner electrode 40 is connected to a power supply line (hereinafter referred to as the inner power supply line) 25 via a sealing foil (metal foil) 24.

[0020] An outer electrode 50 is provided on the outer surface 20S of the discharge capacitor 20. The outer electrode 50 exposes the outer surface 20S of the discharge capacitor 20 and is formed by spirally winding a conductive wire so as not to block the ultraviolet rays radiated from the discharge inside the discharge capacitor. It includes a discharge electrode portion (hereinafter referred to as a spiral electrode portion) 51 that mainly contributes to the formation of the discharge inside the discharge capacitor, and holding electrode portions (hereinafter referred to as annular portions) 52, 54, 56 that hold and electrically connect the spiral electrode portion 51 and are formed by annularly winding a conductive plate so as to cover the outer surface 20S of the discharge capacitor 20.

[0021] The spiral electrode portion 51 is wound along the lamp axis C so as to be in close contact with the outer surface 20S from the tip side to the rear end side of the cylindrical portion of the discharge capacitor 20. By welding or winding it to the annular portions 52, 54, 56, it is an electrode portion that is electrically connected while suppressing the formation of voids with respect to the outer surface of the discharge capacitor 20 and movement along the lamp axis C, and is disposed on the outer surface 20S so that a thin-line discharge extending over the entire range of the lamp axis direction of the discharge space S occurs. The annular portions 52, 56 are located at both ends of the spiral electrode portion 51 of the discharge capacitor 20. In particular, the annular portion 56 is positioned so as to face the tip portion 40T of the inner electrode 40 in the lamp radial direction. The annular portion 54 is disposed near the center of the lamp therebetween. The annular portion 54 is located closer to the center of the lamp than the tip portion 40T of the inner electrode 40.

[0022] The annular portions 52, 54, 56 are configured by welding the ends of a conductive plate wound in a cylindrical shape, and by shortening the circumferential length, they make surface contact over the entire circumference of the outer surface 20S of the discharge capacitor 20, suppressing the formation of voids with respect to the outer surface 20S of the discharge capacitor 20 and movement along the lamp axis C, and holding the spiral electrode portion 51 by sandwiching it along the lamp axis C. Further, an extension portion 54B is provided on the annular portion 54 disposed near the center of the lamp.

[0023] The extension portion 54B extends along a direction away from the outer surface of the discharge capacitor (here, linearly extends along the lamp radial direction), and its tip portion 54BT is connected to the outer power supply line 70 on the ground side at the connection portion BT.

[0024] The shortest distance interval between the discharge capacitor 20 and the outer power supply line 70, that is, the distance interval D from the outer surface 20S of the discharge capacitor 20 to the connection part BT, can be determined in consideration of the flow situation of the source gas, the fluid for treatment, etc. flowing along the periphery of the discharge capacitor 20, and the ultraviolet illuminance in the region where the outer power supply line 70 and the connection part BT are located. For example, in the case of ultraviolet rays with a wavelength of 172 nm, considering that the ultraviolet ray intensity ratio attenuates to 50% or less with a progress of about 3 mm and to 20% or less with a progress of about 6 mm, the distance interval D is determined to be equal to or greater than the distance (ultraviolet attenuation distance) at which the ultraviolet ray intensity ratio radiated from the discharge capacitor 20 attenuates to 50%, preferably equal to or greater than the distance at which it attenuates to 20%.

[0025] When a high-frequency high voltage is applied between the inner electrode 40 and the outer electrode 50, dielectric barrier discharge occurs, and here, ultraviolet rays in the vacuum ultraviolet wavelength range, that is, ultraviolet rays with a wavelength of 200 nm or less (for example, a wavelength of 172 nm), are radiated out of the discharge capacitor 20 as excimer light. When a source gas containing oxygen flows around the excimer lamp 10 in the flow path tube 90, ozone is generated, and the gas containing ozone is discharged out of the ozone generator 100. Thereby, sterilization, deodorization, etc. can be performed.

[0026] FIG. 2 is a schematic block diagram of the ozone generator 100. Here, only the configuration related to the lighting control of the excimer lamp 10 is shown.

[0027] The control unit 110 controls the operation of the ozone generator 100, including the lighting control of the excimer lamp 10. The lamp ON / OFF circuit 120 is connected to the lamp power supply circuit 130 and controls the operation of the lamp power supply circuit 130 so as to be able to execute the repeated periodic lighting and extinguishing of the excimer lamp 10. The battery 140 that supplies power to each circuit such as the control unit 110 is composed of a secondary battery such as a lithium battery and can be charged via a USB terminal cable.

[0028] The ozone generator 100 is provided in the device housing 100A and includes an operation unit 150 that is operated for starting the ozone generation operation, setting the ozone generation time, and the like. A switch circuit (hereinafter referred to as an operation detection switch) 160 detects an input operation by the user to the operation unit 150 and is configured by a touch sensor. An indicator 170, which is composed of an LED or the like and is provided on the housing 100A, can display the ozone generation time, the remaining battery level, and the like.

[0029] In the present embodiment, before shifting from an unstable discharge state (transient state discharge) immediately after lighting (arcing) to a stable discharge state (steady state discharge), the excimer lamp 10 is turned off (extinguished), and immediately thereafter, it is lit again. By repeating lighting and extinguishing in this way (hereinafter referred to as periodic lighting), a lighting method is adopted in which transient state discharge is continuously generated.

[0030] In dielectric barrier discharge, when a voltage is applied at a predetermined frequency, discharge continues at the portion where converged thin-line microplasma discharge has occurred, and there is a so-called memory effect that discharge does not occur thereafter at the portion where thin-line microplasma discharge has not occurred. Here, in order to reset the so-called memory effect (return to the state before discharge occurs), before generating a steady state discharge in which the memory effect occurs, it is turned off, and a reset lighting operation is performed in which transient state discharge is repeated.

[0031] Periodic lighting is performed based on a frequency f2 that is lower than the frequency f1 of the applied voltage when the excimer lamp 10 is lit by applying a high-frequency high voltage. For example, when the frequency f1 of the applied voltage is determined in the range of 1 kHz to 500 kHz, the frequency f2 is determined in the range of 1 to 60 Hz. In particular, it may be determined in the range of 20 Hz to 40 Hz.

[0032] When the tip 40T of the inner electrode 40 is configured to face only the outer electrode 50 (particularly, the annular portion 56) along the lamp diameter direction and the excimer lamp 10 is lit by periodic lighting, microplasma discharge forms a discharge biased towards the tube wall in the discharge vessel 20, and a dense and uniform discharge does not occur throughout the discharge vessel 20. Therefore, even if the discharge space region along the lamp axis C in the discharge vessel 20 is enlarged, the ozone generation amount does not increase significantly, and low-concentration ozone (a small amount of ozone) can be stably generated. Further, foreign matter emitted from the inner electrode 40 does not accumulate in the region surrounding the discharge space region of the discharge vessel 20, but accumulates on the inner surface of the discharge vessel 20 on the rear end side rather than the tip 40T of the inner electrode 40, so that it is suppressed that ultraviolet rays are blocked by the deposits.

[0033] Further, by performing periodic lighting of the excimer lamp 10, the microplasma discharge (discharge column) generated in the dielectric barrier discharge occurs at different positions every time it blinks (resets). This is due to the fact that microplasma discharge occurs in the space region where the electrical resistance (temperature) is low at the moment of relighting.

[0034] As the transient discharge continuously occurs while shifting to a relatively low-temperature space region, ultraviolet irradiation and ozone generation do not continue in the same region as in the steady-state discharge. Therefore, on the inner surface side of the discharge vessel 20, it is suppressed that foreign matter emitted from the inner electrode 40 continuously adheres to and accumulates in the same region, and it is suppressed that the ultraviolet rays radiated from the discharge vessel are blocked by the deposits and the ozone generation efficiency decreases. Also, on the outer surface side of the discharge vessel 20, chemical reactions (oxidation) of foreign matter adhering to and accumulating at the connection portion between the outer electrode and the power supply line are suppressed, so that the fixation of foreign matter, the deterioration of the electrode, and abnormal discharge are suppressed. Further, the temperature of the entire discharge vessel 20 does not increase due to the discharge occurring uniformly in the discharge vessel 20, and the temperature rise near the surface of the discharge vessel 20 where the ultraviolet intensity is high is suppressed, so that thermal decomposition by ozone is suppressed. Therefore, it becomes possible to stably generate low-concentration ozone continuously, and the ozone generation time can be lengthened with respect to the battery capacity.

[0035] Also, in lighting and exposure, in order to intentionally generate snaking and flickering that are regarded as abnormal discharge states, a thin, wire-shaped microplasma discharge converging from the tip 40T of the internal electrode 40 extends, and irregular and complex periodic changes constantly occur along the inner surface of the discharge vessel 20. By setting the discharge state in this way, ultraviolet rays are not continuously irradiated onto the same region of the discharge vessel 20, and visually impressive transient discharges are repeated, making it possible to blend in with interior design even when installed indoors.

[0036] Since the ultraviolet irradiance radiated from the transient discharge is lower than the ultraviolet irradiance radiated from the steady-state discharge, if the transient discharge is continued, the ozone generation amount will be less than half of the ozone generation amount by the steady-state discharge. Also, in order to continue ozone generation at a low concentration, the operation of the intake fan 180 is controlled so that the flow rate of the source gas is 1 m 3 / min or less.

[0037] The operation detection switch 160 monitors (detects) input operations to the operation unit 150 at regular time intervals. The frequency f3 as the detection cycle (detection period) of this operation detection switch 160 is set to n times (n is a natural number) the frequency f2. That is, monitoring is performed in accordance with the periodic lighting (reset timing) operation of the excimer lamp 10. This prevents any influence on the lamp power supply circuit 130 during the transient discharge.

[0038] The excimer lamp 10 is not limited to the configuration of a discharge vessel in which a part of the above-described inner electrode 40 is exposed to the discharge space S, and the shape of the discharge vessel, the arrangement configuration of the inner electrode, etc. are arbitrary. For example, it can also be applied to a double-tube structure lamp. Also, it can be configured not only as a small ultraviolet irradiation device or ozone generation device driven by a battery, but also as an ultraviolet irradiation device or ozone generation device using a commercial power supply.

Explanation of Reference Numerals

[0039] 10 Excimer lamp 20 Discharge capacitor 100 Ozone generator 110 Control unit 120 Lamp ON / OFF circuit

Claims

1. An excimer lamp and, a control unit for controlling the lighting of the excimer lamp, characterized in that the control unit repeats the lighting and extinguishing of the excimer lamp so as to continue the discharge in the transient state, an ultraviolet irradiation device.

2. The ultraviolet irradiation device according to claim 1, characterized in that the frequency f2 at which the lighting and extinguishing of the excimer lamp are periodically repeated is lower than the frequency f1 of the voltage applied to the excimer lamp.

3. The ultraviolet irradiation device according to claim 2, characterized in that the frequency f2 is determined in the range of 1 to 60 Hz.

4. further comprising an operation detection switch for detecting an input operation by a user, the ultraviolet irradiation device according to any one of claims 2 to 3, characterized in that the operation detection switch detects the input operation at a period of frequency f3 = f2 × n (n is a natural number).

5. An ozone generation device comprising the ultraviolet irradiation device according to any one of claims 1 to 4.

6. An excimer lamp and, a control unit for controlling the lighting of the excimer lamp, characterized in that the control unit repeats the lighting and extinguishing of the excimer lamp so as to continue the discharge in the transient state, an ozone generation device.

7. The ozone generation device according to claim 6, characterized in that the ozone generation amount when repeating the discharge in the transient state is half or less of the ozone generation amount in the steady-state discharge.

8. further comprising a flow path tube in which the excimer lamp is disposed, The flow rate of the fluid containing oxygen flowing through the flow path tube is 1 m ３ / min or less, and the ozone generator according to claim 6 or 7, characterized in that.

9. further comprising an operation detection switch for detecting an input operation by a user, the ozone generation device according to any one of claims 6 to 8, characterized in that the operation detection switch detects the input operation at a detection period of frequency f3 = f2 × n (f2 is the frequency at which the lighting and extinguishing of the excimer lamp are repeated, n is a natural number).

10. A method for lighting an excimer lamp comprising an electrode at least partially exposed in at least a discharge container, characterized in that the lighting and extinguishing of the excimer lamp are repeated so as to continue the discharge in the transient state, a method for lighting an excimer lamp.

Images