JPH0831386A - Dielectric barrier discharge lamp device - Google Patents

Abstract

(57) [Summary] (Modified) [Object] To provide a dielectric barrier discharge lamp device that is compact, can start discharge at a relatively low voltage, and has sufficient luminous efficiency. [Structure] A second dielectric 2 provided with a gap facing the first dielectric 3 of the dielectric barrier discharge which also serves as a discharge container.
A first electrode 4 provided on the first surface of the first dielectric material that does not face the gap for performing a dielectric barrier discharge, and a first electrode 4 provided on the first surface of the second dielectric material that does not face the gap. And a second electrode 5 for performing a dielectric barrier discharge, and a discharge gas formed by the second surfaces of the first and second dielectrics facing the gap and forming excimer molecules by the dielectric barrier discharge. In a dielectric-barrier discharge lamp device comprising a discharge space 8 filled with Pd and a light extraction window for extracting light from excimer molecules, a third electrode 2 is provided on the second surface of the first dielectric.
1 is provided, and means for applying an AC voltage to the first and third electrodes and the first and second electrodes is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is, for example, a kind of discharge lamp used as an ultraviolet light source for photochemical reaction, which forms excimer molecules by dielectric barrier discharge and utilizes light emitted from the excimer molecules. To improve the so-called dielectric barrier discharge lamp device.

[0002]

2. Description of the Related Art As a technique related to the present invention, there is, for example, Japanese Patent Laid-Open Publication No. 1-144560.
There, the discharge vessel is filled with a discharge gas that forms excimer molecules, and a dielectric barrier discharge (also known as ozonizer discharge or silent discharge. Revised new edition "Discharge Handbook" published by the Institute of Electrical Engineers of Japan, June 1st, 7th edition, 7th edition (See page 263)
Describes a lamp, i.e. a dielectric barrier discharge lamp device, which forms excimer molecules by means of which light emitted from the excimer molecules is utilized, the discharge vessel being cylindrical and at least part of the discharge vessel being Described is a dielectric barrier discharge lamp device which also serves as a dielectric of the dielectric barrier discharge, the dielectric is light transmissive, and a conductive mesh electrode is provided on at least a part of the dielectric. .

Also, on page 2-173 of the second volume of the 1994 National Conference of the Institute of Electrical Engineers of Japan, the first electrode embedded in the cylindrical ceramic and the coaxially arranged in the ceramic cylinder are provided. Pyrex tube, a second electrode provided inside the Pyrex tube, and an ozone generator having a third electrode provided inside the ceramic cylinder, the first electrode and the third electrode A method is described in which discharge is performed between an electrode and the first electrode and the second electrode.

An outline of a general dielectric barrier discharge will be described below with reference to FIG. 3 which is a schematic view of a conventional dielectric barrier discharge lamp device. The discharge vessel 1 has a hollow cylindrical shape in which an inner tube 2 and an outer tube 3 made of glass, which is a dielectric material, are coaxially arranged. On the outer surface of the outer tube 3, a light-passing dielectric barrier discharge electrode 4 is provided, and on the outer surface of the inner tube 2, an electrode 5 for dielectric barrier discharge also serving as a light reflecting film formed by vapor deposition of aluminum is provided. It is provided. To protect the electrode 5 mechanically and chemically, a protective film 9 made of boron nitride is provided on the electrode 5. A getter chamber 6 for accommodating a getter 7 is provided at one end of the discharge vessel 1. When the discharge space 8 is filled with a discharge gas that forms excimer molecules by the dielectric barrier discharge and a voltage is applied between the electrodes 4 and 5 by the AC power supply 10, a dielectric barrier discharge is generated in the discharge space 8 and the excimer is discharged. Light is emitted. The getter 7 has a function of removing the impure gas (for example, H ₂ O) in the discharge space 8 and stabilizing the discharge.

In a normal arc discharge generated by an arc discharge lamp or the like having a medium pressure or high pressure of several tens of torr or more, there is only one discharge plasma in the discharge space, and one small electrode bright spot is present on the electrode surface. Has occurred. That is, even if the area of the electrode is increased, the portion that substantially functions as the electrode is a very small portion, and there is only one line of discharge plasma. On the other hand, as described in the above discharge handbook, in the dielectric barrier discharge, the dielectric is inserted in the discharge path. Since this dielectric prevents the discharge plasma from converging in a single line, a very small discharge plasma with a very small plasma diameter and a very short discharge duration (hereinafter referred to as microplasma) is discharged. There will be many in space.
One of the causes for excimer light to be emitted with high efficiency in the dielectric barrier discharge lamp device is the presence of the above-mentioned multi-line minute discharge plasma.

[0006]

The dielectric barrier discharge lamp device as described above is useful because it has various features that conventional glow discharge lamps and arc discharge lamps do not have. However, the conventional dielectric barrier discharge lamp device has the following drawbacks. First of all, as is apparent from FIG. 3, since there are two dielectrics 2 and 3 between the electrodes 4 and 5, the voltage drop in the dielectric is large, and therefore a high voltage is required to start the discharge. The drawback occurs. That is, a power source that generates a high voltage for starting discharge is required, and as a result, the device becomes large.

Secondly, in order to increase the light output, if the amount of electric power injected into the discharge space 8 is increased while the size of the discharge vessel 1 is kept constant, the thickness of the microplasma increases, As a result, there is a drawback that the efficiency of generating excimer molecules is reduced and the efficiency of light emission is reduced. On the other hand, in order to increase the amount of power injected into the discharge space 8 while keeping the thickness of the microplasma constant so that the luminous efficiency does not decrease, the discharge space must be increased, resulting in a larger lamp. There are drawbacks.

For example, a UV light source of high brightness is required for UV curing of paint and dry cleaning of a metal surface using UV rays, and a dielectric barrier discharge lamp device is expected as such a UV light source. In that case, compactness is also required for the dielectric barrier discharge lamp device in order to make the entire device compact. However, the above-mentioned drawbacks exist in the conventional dielectric barrier discharge lamp device, so that a power source for generating a high voltage is required and the compactness is limited. Further, when an increase in light output is required, it is difficult to achieve light emission with high luminous efficiency while maintaining the compactness of the lamp.

The present invention has been made based on the above circumstances, and its problem is a dielectric barrier which is compact, can start discharge at a relatively low voltage, and has sufficient luminous efficiency. An object of the present invention is to provide a discharge lamp device.

[0010]

In order to solve the above problems, the invention of claim 1 of the present invention provides a first dielectric for a dielectric barrier discharge which also serves as a discharge container, and the first dielectric. A second dielectric provided facing each other with a gap, and a second dielectric provided on at least a part of the first surface of the first dielectric not facing the gap for performing dielectric barrier discharge. One electrode, a second electrode that is provided on at least a part of the first surface of the second dielectric that does not face the gap, and that performs a dielectric barrier discharge, and the first electrode that faces the gap. A discharge space formed by a second surface of the dielectric and a second surface of the second dielectric, the discharge space being filled with a discharge gas that forms excimer molecules by the dielectric barrier discharge. And a light extraction window for extracting light from the excimer molecule. In an electric barrier discharge lamp device, a third electrode is provided on at least a part of the second surface of the first dielectric, and the first electrode, the third electrode, and the first electrode. And means for applying an AC voltage to the second electrode, respectively.

According to a second aspect of the present invention, in the first aspect of the invention, the first dielectric has a light-transmitting property and also serves as the light extraction window portion, and the first electrode. When,
The third electrode is configured to be light transmissive.

According to a third aspect of the present invention, in the invention of the first aspect or the second aspect of the invention, the phase of the AC voltage applied to the first electrode and the third electrode, and the first voltage The phase of the AC voltage applied to the electrode and the AC voltage applied to the second electrode is approximately the same.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the phase of the AC voltage applied to the first electrode and the third electrode, and the first electrode And the phase of the AC voltage applied to the second electrode is approximately opposite.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the electric power supplied to the discharge between the first electrode and the third electrode is the first electrode. The electric power supplied to the discharge between the one electrode and the second electrode is one tenth or less.

[0015]

According to the first aspect of the present invention, the third electrode is provided on at least a part of the second surface of the first dielectric, and the first electrode and the third electrode are provided. And means for applying an AC voltage to the first electrode and the second electrode are provided respectively, so that only one dielectric exists between the first electrode and the third electrode. Therefore, a creeping discharge is generated on the surface of the second surface of the first dielectric simply by applying a relatively low voltage between the first electrode and the third electrode. Then, this creeping discharge becomes an electron source, and the discharge between the first electrode and the second electrode also starts only by applying a relatively low voltage between the electrodes. That is, there is no need to generate a high voltage in the power supply,
As a result, the device becomes compact. When a gas containing halogen such as chlorine or bromine is used as the discharge gas, the discharge starting voltage becomes particularly high, so that the advantage of decreasing the discharge starting voltage obtained by configuring the third electrode becomes large. .

In the conventional dielectric barrier discharge lamp device, excimer light is emitted from the dielectric barrier discharge between the first electrode and the second electrode. In the present invention, excimer light is emitted from each of the creeping discharge generated on the surface of the second surface of the first dielectric and the dielectric barrier discharge between the first electrode and the second electrode. It Therefore, even when the compactness of the lamp is maintained, a high light output can be obtained with higher efficiency than in the conventional case. The mechanism of the discharge plasma in the portion where the above two discharges are superposed is not necessarily clear, but the spatial distribution of the discharge plasma changes due to the superposition of the two discharges,
It may be possible to contribute to the high efficiency of light output.

According to a second aspect of the present invention, in the first aspect of the present invention, the first dielectric is light-transmissive and also serves as the light extraction window portion, and the first electrode. When,
Since the third electrode is configured to be light transmissive,
The same effect as that of the invention of claim 1 can be obtained, and a creeping discharge that occurs on the surface of the second surface of the first dielectric and between the first electrode and the second electrode There is an advantage that the efficiency of extracting excimer light from the dielectric barrier discharge, that is, the efficiency of light emission from the light extraction window portion is increased.

The dielectric barrier discharge plasma between the first electrode and the second electrode spreads on the dielectric surface on the positive electrode side. The invention of claim 3 of the present invention is the invention of claim 1 or 2, wherein the phase of the AC voltage applied to the first electrode and the third electrode, the first electrode and the The alternating voltage applied to the two electrodes is configured so that the phases of the alternating voltages are substantially in phase.
The same effect as that of the invention can be obtained, and plasma contributing to creeping discharge generated on the surface of the second surface of the first dielectric substance that contributes to the emission of excimer light, and also contributes to the emission of excimer light. Since the plasma due to the dielectric barrier discharge between the first electrode and the second electrode does not overlap with each other, the luminous efficiency can be increased.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the phase of the AC voltage applied to the first electrode and the third electrode, and the first electrode And the phase of the AC voltage applied to the second electrode is approximately opposite to each other, the same effect as that of the invention of claim 1 or 2 can be obtained, and the electric field strength of the discharge space can be obtained. Has the advantage that the discharge starting voltage becomes lower.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the electric power supplied to the discharge between the first electrode and the third electrode is the first electrode. Since the configuration is such that the electric power supplied to the discharge between the one electrode and the second electrode is one tenth or less, the same effect as that of the invention according to any one of claims 1 to 4 can be obtained. In addition to being possible, it has the following advantages. The discharge between the first electrode and the third electrode, that is, the generation of excimer light due to the discharge generated on the surface of the second surface of the first dielectric is very small, but the discharge is an electron source. Since the electrons necessary for starting the discharge between the first electrode and the second electrode are sufficiently supplied, the discharge between the first electrode and the second electrode should be performed instantaneously. You can Therefore, excimer light can be interrupted only by interrupting the applied voltage between the first electrode and the second electrode without using a mechanical shutter. Note that the electric power described here is the same as the condition under which the first electrode and the third electrode are simultaneously discharged between the first electrode and the second electrode and the first electrode and the second electrode. This is the electric power when a single discharge is performed between the electrode and the third electrode and between the first electrode and the second electrode.

[0021]

1 shows a dielectric barrier discharge lamp device according to a first embodiment of the present invention. The discharge vessel 1 is made of synthetic quartz glass, and has an inner tube 2 having an outer diameter of 14 mm which is a second dielectric,
The outer tube 3 having an inner diameter of 26 mm, which is a first dielectric, is coaxially arranged to form a hollow cylinder. On the outer surface of the outer tube 3, a first electrode 4 for discharging a light-transmitting dielectric barrier made of a metal net is formed, and on the outer surface of the inner tube 2, a dielectric barrier which also functions as a light reflection film formed by vapor deposition of aluminum. Second electrodes 5 for discharging are provided respectively. A getter chamber 6 for accommodating a getter 7 is provided at one end of the discharge vessel 1. A protective film 9 made of boron nitride is provided on the electrode 5 in order to mechanically and chemically protect the electrode 5 formed by vapor deposition of aluminum. A third electrode 21 made of a spiral metal wire is provided on the inner surface of the outer tube 3. In the discharge space 8, xenon was filled at 60 kPa as a discharge gas for forming excimer molecules by dielectric barrier discharge.

A power source 10 is connected to the outer electrode 4 and the inner electrode 5, a power source 20 is connected to the outer electrode 4 and the third electrode 21, and the phases of the voltages of the power source 10 and the power source 20 are approximately the same. When a high frequency voltage of 20 kHz was applied, the following effects were obtained. First of all, compared to the case where a voltage is applied only between the outer electrode 4 and the inner electrode 5 as usual, 5
The discharge started at a low voltage of 0% or less, so that the power supply and the entire device can be downsized. Secondly, by applying a voltage between the first electrode and the third electrode, a creeping discharge generated on the inner surface of the outer tube 3 and between the first electrode and the second electrode Since excimer light is emitted from the dielectric barrier discharge of, the vacuum ultraviolet ray having the maximum value at the wavelength of 172 nm was obtained with high efficiency and large light output while maintaining the compactness of the lamp.

The dielectric barrier discharge lamp device of the second embodiment of the present invention is the same as that of the first embodiment except that the phases of the voltages of the power source 10 and the power source 20 are approximately opposite phases. In this example, there was an advantage that the discharge starting voltage was further lowered.

The dielectric barrier discharge lamp device of the third embodiment of the present invention has the same structure as the first embodiment, but uses a mixed gas of chlorine and xenon as the discharge gas, and Discharge between the first electrode 4 and the third electrode 21,
That is, the electric power supplied to the discharge generated on the inner surface of the outer tube 3 is set to be one tenth or less of the electric power supplied to the discharge between the first electrode 4 and the second electrode 5. is there. The generation of excimer light due to the discharge between the first electrode and the third electrode, that is, the discharge generated on the inner surface of the outer tube 3, is extremely small, but the discharge serves as an electron source and serves as the first electrode. The electrons required to start the discharge between the second electrode and the second electrode are always sufficiently supplied. Therefore, the discharge between the first electrode and the second electrode can be instantaneously performed even though chlorine, which has a particularly high discharge start voltage, is used as a part of the discharge gas. Therefore,
Excimer light can be interrupted by simply interrupting the applied voltage between the first electrode and the second electrode without using a mechanical shutter.

A dielectric barrier discharge lamp device according to the fourth embodiment of the present invention is shown in FIG. The difference from the first embodiment is that the first electrode 31 and the second electrode 32 are metal thin film electrodes, one tip 34 of the second dielectric is closed, and the light output is light. It is taken out through the take-out window 33, and the discharge gas is argon. Also in this example, the vacuum ultraviolet ray having the maximum value at the wavelength of 124 nm was obtained with high efficiency and large light output while keeping the compactness of the lamp.

Although each of the above-mentioned embodiments is a coaxial cylindrical lamp, it is obvious that the present invention can be applied to a flat type dielectric barrier discharge lamp using a flat plate-shaped dielectric.

[0027]

As described above, according to the present invention, the following effects can be obtained. In the invention of claim 1 of the present invention, a third electrode is provided on at least a part of the second surface of the first dielectric, and the first electrode, the third electrode and the first electrode are provided. Since the means for applying an AC voltage to the electrode and the second electrode is provided, only one dielectric is present between the first electrode and the third electrode, and By simply applying a relatively low voltage between the electrode and the third electrode, a creeping discharge occurs on the surface of the second surface of the first dielectric, and this creeping discharge becomes an electron source, The discharge between the first electrode and the second electrode can also be started only by applying a relatively low voltage between the electrodes. That is, it is not necessary to generate a high voltage in the power supply, and as a result, the device can be made compact. When a gas containing halogen such as chlorine or bromine is used as the discharge gas, the discharge starting voltage becomes particularly high, so that the advantage of decreasing the discharge starting voltage obtained by configuring the third electrode becomes large. .

Excimer light is emitted from the creeping discharge generated on the surface of the second surface of the first dielectric and the dielectric barrier discharge between the first electrode and the second electrode. Therefore, even when the compactness of the lamp is maintained,
It is possible to obtain a high optical output with high efficiency as compared with the conventional one.

According to a second aspect of the present invention, in the first aspect of the invention, the first dielectric is light-transmissive and also serves as the light extraction window portion, and the first electrode is also used. When,
Since the third electrode is configured to be light transmissive,
The same effect as that of the invention of claim 1 can be obtained, and a creeping discharge that occurs on the surface of the second surface of the first dielectric and between the first electrode and the second electrode It is possible to increase the efficiency of extracting excimer light from the dielectric barrier discharge, that is, the light emission efficiency from the light extraction window portion.

The dielectric barrier discharge plasma between the first electrode and the second electrode spreads on the dielectric surface on the positive electrode side. The invention of claim 3 of the present invention is the invention of claim 1 or 2, wherein the phase of the AC voltage applied to the first electrode and the third electrode, the first electrode and the The alternating voltage applied to the two electrodes is configured so that the phases of the alternating voltages are substantially in phase.
While being able to obtain the same effect as that of the invention, a creeping discharge that occurs on the surface of the second surface of the first dielectric,
Since the overlapping of plasma due to the dielectric barrier discharge between the first electrode and the second electrode is small, the luminous efficiency can be increased.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the phase of the AC voltage applied to the first electrode and the third electrode, the first electrode and the Since the phase of the AC voltage applied to the second electrode is approximately opposite, the same effect as that of the invention of claim 1 or 2 can be obtained, and the electric field strength of the discharge space increases. The discharge start voltage can be lowered.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the invention, the electric power supplied to the discharge between the first electrode and the third electrode is Since the configuration is such that the electric power supplied to the discharge between the one electrode and the second electrode is one tenth or less, the same effect as that of the invention according to any one of claims 1 to 4 can be obtained. In addition to being possible, it has the following effects. The discharge between the first electrode and the third electrode, that is, the generation of excimer light due to the discharge generated on the surface of the second surface of the first dielectric is very small, but the discharge is an electron source. Since the electrons necessary for starting the discharge between the first electrode and the second electrode are sufficiently supplied, the discharge between the first electrode and the second electrode should be performed instantaneously. You can Therefore, excimer light can be interrupted only by interrupting the applied voltage between the first electrode and the second electrode without using a mechanical shutter.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a dielectric barrier discharge lamp device of the present invention.

FIG. 2 is an explanatory view of another embodiment of the dielectric barrier discharge lamp device of the present invention.

FIG. 3 is an explanatory diagram of a conventional dielectric barrier discharge lamp device.

[Explanation of Codes] 1 discharge vessel 2 second dielectric 3 first dielectric 4,31 first electrode 5,32 second electrode 7 getter 8 discharge space 10,20 power supply 21,35,41 third Electrode 33 Light extraction window

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tateman Hiramoto 1194 Sado Bessho-cho, Himeji City, Hyogo Prefecture Ushio Denki Co., Ltd. Incorporated (72) Inventor Nozomi Hishinuma 1194 Sado, Bessho-cho, Himeji-shi, Hyogo Ushio Electric Co., Ltd.

Claims (5)

[Claims] 1. A first dielectric for a dielectric barrier discharge that also serves as a discharge container, a second dielectric provided facing the first dielectric with a gap, and in the gap. A first electrode for performing a dielectric barrier discharge provided on at least a part of the first surface of the first dielectric that does not face, and a first surface of the second dielectric that does not face the gap A second electrode for performing a dielectric barrier discharge provided on at least a part of the second electrode, a second surface of the first dielectric and a second surface of the second dielectric facing the gap, And a discharge space in which the discharge space is filled with a discharge gas that forms excimer molecules by the dielectric barrier discharge, and a light extraction window portion that extracts light from the excimer molecules. In the device, the second surface of the first dielectric is A third electrode is provided at least at a part, and means for applying an AC voltage to the first electrode, the third electrode, and the first electrode and the second electrode is provided. Dielectric barrier discharge lamp device. 2. The first dielectric has a light-transmitting property and also serves as the light-extracting window portion, and the first electrode and the third electrode have a light-transmitting property. The dielectric barrier discharge lamp device according to claim 1, which is characterized. 3. The phase of the AC voltage applied to the first electrode and the third electrode and the phase of the AC voltage applied to the first electrode and the second electrode are substantially in phase. The dielectric barrier discharge lamp device according to claim 1 or 2, wherein. 4. The phase of the AC voltage applied to the first electrode and the third electrode and the phase of the AC voltage applied to the first electrode and the second electrode are approximately opposite phases. The dielectric barrier discharge lamp device according to claim 1, wherein the dielectric barrier discharge lamp device is provided. 5. The power supplied to the discharge between the first electrode and the third electrode is less than one tenth of the power supplied to the discharge between the first electrode and the second electrode. The dielectric barrier discharge lamp device according to any one of claims 1 to 4, wherein