JP2002042736A - Dielectric barrier discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric barrier discharge lamp for improving cooling efficiency of a discharge container of a discharge tube by a comparatively simple constitution. SOLUTION: In an external electrode 1 or an internal electrode 3 of the discharge container 2 of a hollow coaxial duplex structure, many projected heat radiating plates 12 and 32 are integrally or separately formed. By increasing contact area with fluid for cooling, cooling efficiency of the dielectric barrier discharge lamp is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge lamp,
In particular, the present invention relates to a dielectric barrier discharge lamp for cooling a discharge vessel of the dielectric barrier discharge lamp.

[0002]

2. Description of the Related Art For example, a dielectric barrier discharge lamp has been put to practical use for generating ultraviolet rays for exposure to photochemical reactions or semiconductor devices. A general conventional dielectric barrier discharge lamp is disclosed, for example, in JP-A-6-310103 and JP-A-6-310104, “Dielectric Barrier Discharge Lamp”. In addition, since such a dielectric barrier discharge lamp generates heat, a technology for cooling the dielectric barrier discharge lamp using a cooling fluid to maintain the luminous efficiency and extend the life, that is, a cooling type A dielectric barrier discharge lamp is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-78.
No. 592, "Dielectric barrier discharge lamp" and JP-A-7-169443, "Dielectric barrier discharge lamp device".

FIGS. 7 and 8 are views showing the structure of the above-mentioned conventional cooled dielectric barrier discharge lamp. The dielectric barrier discharge lamp 100 shown in FIG. 7 has a discharge vessel 101 having a double structure including an inner tube 102 and an outer tube 103. On the outer surface of the outer tube 103, a spiral or mesh cylindrical electrode 104 is provided.
However, an aluminum electrode 105 is formed on the inner surface of the inner tube 102. In a discharge space 107 formed between the inner tube 102 and the outer tube 103, a discharge gas such as xenon gas is sealed, and a barium getter 106 is arranged. A high-frequency voltage of, for example, 20 kHz generated by a high-frequency power source 108 is applied between the cylindrical electrode 104 and the aluminum electrode 105 to excite the discharge gas described above. In addition, for cooling, the bases 110 and 111 are attached to both ends of the discharge vessel 101, and the discharge lamp 100 is cooled by passing nitrogen gas or the like through the central vent holes 112 and 113 and the central hole of the inner tube 102. . In addition, aluminum electrode 105
A protective film 120 of silicon rubber or the like is formed on the inner surface.

On the other hand, a cooled dielectric barrier lamp discharge lamp 100 shown in FIG. 8 has an inner tube 102, an outer tube 103, a cylindrical electrode 104, an aluminum electrode 105, a getter 106, and a discharge space 107 shown in FIG. Same as lamp 100. However, such a discharge lamp element is housed in the protective tube 130 and further covered by the flange 131. From the center of the flange 131, a conduit 140 is attached to one end of the discharge vessel using an inorganic adhesive 141 or the like, and a cooling fluid such as nitrogen gas is caused to flow from an inlet 116 at the upper end of the conduit 140.
Through the center hole of 2 and the outside of the outer tube 103, the flange 13
It is made to flow out of the outlet 117 formed in 1. The space between the protection tube 130 and the flange 131 is sealed by an O-ring 143. The flange 131 and the conduit 140 have small holes 119 and 1 respectively.
18 are formed, and the lead wire 114 for the aluminum electrode 105 is inserted. Lead wire 115 for cylindrical electrode 104 is also flanged
Derived outside via 131. On the inner surface of the aluminum electrode 105, a protective film 120 such as boron nitride is provided. Here, the outer diameter D1 of the inner pipe 102 and the inner diameter D2 of the outer pipe 103
Are, for example, 14 mm and 25 mm, respectively.

[0005]

However, the cooling structure of such a conventional cooling type dielectric barrier discharge lamp is merely for cooling nitrogen gas or the like inside a smooth inner tube having an aluminum electrode formed on the inner surface. Since only the fluid is passed, the cooling efficiency of the discharge vessel is low. Therefore, there has been a disadvantage that the discharge vessel cannot be sufficiently cooled or a large amount of cooling fluid is required. Therefore, an object of the present invention is to provide a dielectric barrier discharge lamp having a high cooling efficiency and capable of sufficiently cooling a discharge vessel using a small amount of cooling fluid.

[0006]

According to the dielectric barrier discharge lamp of the present invention, a discharge gas is sealed in a discharge space of a hollow double tubular discharge vessel, and an external electrode and an outer electrode provided on an outer surface and an inner surface of the discharge vessel, respectively. A discharge lamp that applies a high-frequency voltage between internal electrodes to excite a discharge gas to emit light, and has a large number of heat sinks on one or both of the internal and external electrodes to increase the contact area with the cooling fluid It is configured so that

Further, according to a preferred embodiment of the dielectric barrier discharge lamp of the present invention, the heat radiating plate of the internal electrode or the external electrode is formed by adding to the cylindrical portion of the internal electrode or the external electrode, respectively. This radiator plate is formed of metal, ceramic, plastic, or the like. The internal or external electrodes are formed by processing a conductive metal plate into a corrugated or bellows shape and attaching it to the inner or outer surface of the discharge vessel. Further, the heat radiating plate of the internal electrode is formed in a radially divided plate shape along the longitudinal direction of the internal electrode, and the cooling gas or liquid is passed along the divided plate.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of a preferred embodiment of a dielectric barrier discharge lamp according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing the basic structure of a dielectric barrier discharge lamp according to the present invention. The dielectric barrier discharge lamp is, for example, a spiral (spiral) or mesh external electrode 1, a discharge vessel 2 formed of a hollow coaxial double tubular dielectric glass, or the like, and disposed on the inner surface of the discharge vessel 2. And a discharge space 4 filled with a discharge gas. To turn on the dielectric barrier discharge lamp, a high frequency voltage of, for example, 20 kHz is applied between the external electrode 1 and the internal electrode 3. The feature of the dielectric barrier discharge lamp of the present invention is the external electrode 1 and / or the internal electrode 3.
6 to obtain various embodiments of the dielectric barrier discharge lamp of the present invention described below.

FIGS. 2 and 3 are electrode configuration diagrams of a first embodiment of the dielectric barrier discharge lamp according to the present invention. FIG. 2 shows an internal electrode 3A used in the dielectric barrier discharge lamp of the first embodiment. 2A and 2B are a longitudinal sectional view and a transverse sectional view, respectively, of the internal electrode 3A. The internal electrode 3A has a substantially cylindrical electrode portion 31,
A cooling radiator plate (fin) 32 protrudes from the inner surface of the cylindrical electrode portion 31 toward the center. These heat sinks 32
As is clear from FIGS. 2A and 2B, a plurality of are formed at substantially constant intervals in the longitudinal direction and the circumferential direction. The outer surface of the cylindrical electrode portion 31 is the discharge vessel 2 shown in FIG.
In close contact with the inner surface of the hollow part. These heat radiating plates 32 may be formed integrally with the cylindrical electrode portion 31 or may be formed separately. The cylindrical electrode portion 31 is preferably formed of a metal or an alloy having good conductivity and good heat conductivity such as aluminum. On the other hand, the heat radiating plate 32 is not necessarily required to be conductive as long as it has good thermal conductivity, and can be formed of metal, ceramic, plastic, or the like. However, when the cylindrical electrode portion 31 is formed separately from the heat sink 32, both need to be thermally tightly coupled. The size of the heat radiating plate 32 can be appropriately selected depending on the required cooling performance, strength against a cooling fluid, and the like. Cooling gas or liquid passes along the central hole (cooling fluid passage) 33 of the internal electrode 3A, so that the contact area between the radiator plate 32 and the cooling gas or liquid increases, so that the cooling efficiency is improved. It will be appreciated that it will be improved.

FIG. 3 is a longitudinal sectional view of the external electrode 1A used in the first embodiment of the dielectric barrier discharge lamp according to the present invention. This external electrode 1A has a cylindrical electrode portion 11
And a heat radiating plate 12 extending radially outward from the cylindrical electrode portion 11. Also in this external electrode 1A, similarly to the case of the above-described internal electrode 3A, a plurality of heat radiating plates 12 are formed at substantially constant intervals in the longitudinal direction and the circumferential direction. Further, the cylindrical electrode portion 11 and the heat radiating plate 12 may be integrated,
A separate configuration may be used. The external electrode 1A is connected to the internal electrode 3
Unlike A, it needs to be formed of a light transmissive material or have a large number of openings so that the ultraviolet light emitted by the discharge lamp is transmitted to the outside.

Next, FIG. 4 shows an internal electrode 3B used in a second embodiment of the dielectric barrier discharge lamp according to the present invention. FIG. 4A is a development view of the internal electrode 3B.
FIG. 4B shows a state in which the discharge vessel 2 is processed into a cylindrical shape and is attached to a central hollow portion of the discharge vessel 2 shown in FIG. FIG. 4 (A)
And (B), the inner electrode 3B
Is a cylindrical surface forming portion 35 that contacts the inner wall of the hollow portion of the discharge vessel 2.
And a large number of projections 36 projecting from the cylindrical surface forming portion 35, and a substantially bellows-shaped conductive metal plate can be formed integrally by bending. The external electrode 1A in the second embodiment
May be a conventional spiral or mesh electrode, or an external electrode 1A as shown in FIG.

FIG. 5 shows an internal electrode 3C of a dielectric barrier discharge lamp according to a third embodiment of the present invention. The internal electrode 3C is a specific example in which the heat radiation plates 32 and 36 in the internal electrodes 3A and 3B of the first and second embodiments described above are replaced by partition walls (or split plates) 37. In other words, the partition 37 is a plurality of plate-like bodies that are formed radially and pass through the center of the discharge vessel 2. FIG. 5A is a perspective view of the internal electrode 3C, and FIGS. 5B and 5C are cross-sectional views. The partition 37 may have a four-part configuration as shown in FIGS. 5A and 5C or an arbitrary number of partitions such as eight as shown in FIG. 5B. This partition 37 is formed of the internal electrode 3C.
May be formed separately from the cylindrical portion of the above and assembled. With the configuration having such a partition wall 37, the flow path of the cooling fluid described above is divided into a plurality, but the contact area with the cooling fluid is greatly increased as compared with the related art, so that the cooling efficiency is improved. it can.

FIG. 6 shows an external electrode 1D and an internal electrode 3D used in a fourth embodiment of the dielectric barrier discharge lamp according to the present invention. FIG. 6A shows a longitudinal sectional view of the external electrode 1D, and FIG. 6B shows a longitudinal sectional view of the internal electrode 3D. As shown in FIG. 6A, the external electrode 1D is
Smooth cylindrical surface 14 contacting the outer surface of discharge vessel 2 shown in FIG.
And an outer surface that is uneven or corrugated in the longitudinal direction. On the other hand, the internal electrode 3D shown in FIG. 6 (B) has a smooth cylindrical outer surface 38 that comes into contact with the hollow inner surface of the discharge vessel 2 and an inner surface 39 that is uneven or corrugated in the longitudinal direction. Here, the external electrode 1D and the internal electrode 3D may each have an integral structure. Further, the shapes of the concave and convex surfaces 15 and 39 may be relatively gentle as shown in the figure, or may be triangular or square.

The configuration and operation of various embodiments of the dielectric barrier discharge lamp according to the present invention have been described above in detail.
However, these embodiments are merely examples of the present invention, and do not limit the present invention in any way. It will be readily apparent to those skilled in the art that various modifications can be made in accordance with the particular application without departing from the spirit of the invention.

[0016]

As will be understood from the above description, according to the dielectric barrier discharge lamp of the present invention, a large number of heat radiating plates (or a plurality of heat radiating plates (or a plurality of radiating plates) are provided on the contact surface of one or both of the internal electrode and the external electrode with the cooling fluid. Partition),
Since the contact area between these electrodes and the cooling fluid increases,
It is possible to effectively cool the discharge vessel with a small amount of cooling fluid, maintain a high luminous efficiency, and extend the life of the dielectric barrier discharge lamp. Further, the cooling equipment for such a dielectric barrier discharge lamp can be made compact and inexpensive. With this improved cooling efficiency,
Experiments have confirmed that the lamp input is improved about twice in the case of the air-cooled type and about 30 to 50% in the case of the water-cooled type.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a dielectric barrier discharge lamp to which the present invention is applied,

2A and 2B show a configuration of an internal electrode used in a first embodiment of a dielectric barrier discharge lamp according to the present invention, wherein FIG. 2A is a longitudinal sectional view, FIG.

FIG. 3 is a longitudinal sectional view showing a configuration of an external electrode used in the first embodiment of the dielectric barrier discharge lamp according to the present invention;

4A and 4B show internal electrodes used in a second embodiment of the dielectric barrier discharge lamp according to the present invention, wherein FIG.
(B) is a cross-sectional view processed into a cylindrical shape,

FIG. 5 shows internal electrodes used in a third embodiment of the dielectric barrier discharge lamp according to the present invention, wherein (A) is a perspective view,
(B) is a transverse sectional view in the case of eight divisions, (C) is a transverse sectional view in the case of four divisions,

FIG. 6 shows electrodes used in a fourth embodiment of the dielectric barrier discharge lamp according to the present invention, wherein (A) and (B) are longitudinal sectional views of an external electrode and an internal electrode, respectively.

FIG. 7 is a longitudinal sectional view of a first conventional example showing a configuration of a cooled dielectric barrier discharge lamp.

FIG. 8 is a longitudinal sectional view of a second conventional example showing the configuration of a cooled dielectric barrier discharge lamp.

[Explanation of symbols]

 1, 1A, 1D external electrode 2 discharge vessel 3, 3A, 3B, 3C, 3D internal electrode 4 discharge space 5 high-frequency power supply 11, 35 cylindrical electrode part 12, 32, 36 radiator plate 14, 38 smooth cylindrical surface 15, 39 Uneven surface 33 Center hole (passage for cooling fluid) 37 Partition wall

Claims (5)

[Claims] A discharge gas is filled in a discharge space of a hollow double-tube discharge vessel, and a high-frequency voltage is applied between an external electrode and an internal electrode provided on an outer surface and an inner surface of the discharge vessel, respectively. A dielectric barrier discharge lamp that excites and emits light, wherein a large number of heat radiating plates are provided on one or both of the internal electrode and the external electrode to increase a contact area with a cooling fluid. Barrier discharge lamp. 2. The dielectric barrier discharge according to claim 1, wherein the heat radiating plate of the internal electrode or the external electrode is formed by being added to a cylindrical portion of the internal electrode or the external electrode. lamp. 3. The radiator plate according to claim 2, wherein the radiator plate is formed of metal, ceramic, plastic, or the like.
2. The dielectric barrier discharge lamp according to claim 1. 4. The discharge electrode according to claim 1, wherein the internal electrode or the external electrode is formed by processing a conductive metal plate into a corrugated shape or a bellows shape and attaching the processed metal plate to an inner surface or an outer surface of the discharge vessel. Dielectric barrier discharge lamp. 5. The heat radiation plate of the internal electrode is formed in a radially divided plate shape along the longitudinal direction of the internal electrode, and a cooling gas or liquid is passed along the divided plate. The dielectric barrier discharge lamp according to claim 1.