Patent Application
20220262617
This invention relates to an excimer lamp with a discharge vessel having a flat quadrilateral cross section, and more particularly to an excimer lamp provided with electrodes on outer surfaces of the discharge vessel.
Excimer lamps can radiate ultraviolet, in particular, ultraviolet having shorter wavelengths and are therefore used in semiconductor production processes, liquid crystal production processes, ozone generators, and so on.
One example of such excimer lamps is described in JP-A-2013-098015 (Patent Document 1).
Such an excimer lamp 21 is illustrated in
For this discharge vessel 22, for example, a material having excellent UV transmission characteristics of 200 nm or less, for example, silica glass such as synthetic quartz glass or sapphire glass is used.
The discharge vessel 22 contains therein as a light emitting gas a rare gas such as xenon gas or krypton gas, or a mixed gas containing a rare gas and a halogen gas such as chloride, depending on the wavelength of the light to be used.
Lamp bases 30, 30 are attached to both ends of the discharge vessel 22 for fixing the excimer lamp 21 to a light irradiation device.
The structure of this excimer lamp 21 is shown in JP-A-2013-149546 (Patent Document 2), for example, and
A discharge vessel 22 includes a glass tube 221 having a flat quadrilateral cross section, and a sealing member 222 inserted and welded to both ends of the glass tube. An exhaust tube 223 is provided to the sealing member 222. The sealing member 222 is inserted slightly inward from an end portion of the glass tube 221 so that the end portion of the glass tube 221 forms a skirt part 224 that protrudes out beyond the sealing member 222.
In the prior art described in Patent Document 2, a solid electrode 25 is provided at an end portion of an external electrode 24, and a lead 26 that supplies power to the external electrode 24 is connected to this solid electrode 25 by welding with glass solder 27 or the like.
The lamp base 30 is attached so as to cover an end portion of the discharge vessel 22 as illustrated in
These excimer lamps are used for various purposes as mentioned above; however, an excimer lamp that is applied for the process of a flowing gas, for example an ozone generator, is disposed such that its lengthwise direction is along the flow direction of a gas to be processed, and the lamp irradiates the gas with vacuum ultraviolet.
In such a case, there is a problem as follows: the gas to be processed forms eddies in behind (downstream of) the lamp base 30 as illustrated in
The lead 26 for power supply is connected by welding with the glass solder 27 on the (solid electrode 25 of the) external electrode 24 as illustrated in
Vacuum ultraviolet emitted from the excimer lamp travels a short distance in a gas, and attenuates as it is absorbed by the surrounding gas. Even in cases where the excimer lamp is used as the light source for directly irradiating an object to be processed other than gasses to be processed with vacuum ultraviolet, the lamp base has a significantly larger thickness than that of the lamp. Accordingly, the excimer lamp cannot be disposed closely to the object to be processed, and such a situation causes a defect such that effective ultraviolet irradiation cannot be performed.
In view of the problems in the prior art described above, an object of the present invention is to provide an excimer lamp including a discharge vessel including a pair of plane face parts and a pair of side face parts and having a flat, substantially quadrilateral cross section, and a pair of external electrodes each disposed on each of outer surfaces of the plane face parts of the discharge vessel. The excimer lamp whose lamp base provided at an end portion of the discharge vessel has a minimum possible thickness to enable effective ultraviolet irradiation of an object to be processed; and the excimer lamp is suitable for a device in which a gas is made to flow along the longitudinal direction of the lamp to be processed.
To attain the object described above, the invention is characterized in that an auxiliary electrode that extends to a region where a distance between the plane face parts is reduced is provided to an end portion of each of the external electrodes, and a lead that supplies power to the external electrode is connected to the auxiliary electrode in the region where a distance between the plane face parts is reduced.
The invention may be also characterized in that the discharge vessel includes a glass tube having a flat, substantially quadrilateral cross section, and sealing members each welded to near an end portion of the glass tube, the end portion of the glass tube protrudes out beyond the sealing member to form a skirt part. The skirt part has a concave part formed on each of the plane face parts thereof in a direction in which the external electrodes are oriented oppositely, the auxiliary electrode extends to the concave part, and the lead is connected to the auxiliary electrode in the concave part.
The invention may be also characterized in that the discharge vessel is sealed by forming a pinch seal part in an end portion of the discharge vessel, the auxiliary electrode extends to the pinch seal part, and the lead is connected to the auxiliary electrode at the pinch seal part.
According to the present invention, an auxiliary electrode is provided to an end portion of the external electrode, and a lead that supplies power to the external electrode is connected to the auxiliary electrode in a region where the distance between the external electrodes is reduced. Therefore, the lead and its weld do not protrude from the plane face part largely in the thickness direction, which prevents the lamp base that covers the lead and weld from protruding more than the thickness of the discharge vessel as much as possible. Accordingly, the flow of the gas to be processed is not hindered and can flow smoothly along the discharge vessel of the lamp, thus enabling an effective process.
In cases where an object to be processed other than gasses is directly irradiated with ultraviolet, the lamp can be disposed in close vicinity to the object to be processed, which is expected to reduce attenuation of vacuum ultraviolet caused by the air to enable an effective process.
The excimer lamp 1 includes a discharge vessel 2 having a flat, substantially quadrilateral cross section and including a pair of quadrilateral plane face parts 3, 3 and a pair of side face parts 4, 4 extending along side edges in the longitudinal direction of the plane face parts. As illustrated in
The external electrodes 5, 5 may be formed on the outer surfaces of the plane face parts 3, 3 of the discharge vessel 2 by applying a metal paste such as gold paste, or by adhering a piece of transfer paper, for example. At least one of these external electrodes 5 is formed in a mesh form, for example, so as to have a light transmitting part. Ultraviolet generated in the discharge space is emitted through this light transmitting part.
A solid electrode 6 is formed at one end of the external electrode 5.
The cross-sectional shape of the discharge vessel 2 is not necessarily precisely a flat quadrilateral. Both or one of the plane face parts 3 and side face parts 4 may be slightly bulged outward, or concaved inward. Moreover, a trapezoidal shape or parallelogram may also be adopted. These shapes are herein collectively expressed as a substantially quadrilateral shape.
In this first embodiment, the discharge vessel 2 includes a tubular glass tube 2a having a substantially flat quadrilateral cross section, and sealing members 2b each welded to near an end portion of the glass tube. The end portion of the glass tube 2a protrudes out beyond the sealing member 2b to form a skirt part 2c. Concave parts 8, 8 are formed in this skirt part 2c in the direction in which the external electrodes 5 are oriented oppositely.
An auxiliary electrode 7 is connected to the external electrode 5 (solid electrode 6), and extends to the concave part 8.
This auxiliary electrode 7 may be formed by printing, or by applying a conductive paste using a dispenser followed by drying.
A lead 10 that supplies power to the external electrode 5 is connected to the auxiliary electrode 7 by welding with glass solder 11 or the like inside this concave part 8, as illustrated in
When attaching a lamp base such as the one illustrated in
The auxiliary electrode 7 is connected to the solid electrode 6 at the end of the external electrode 5 provided on the plane face part 3 of the discharge vessel 2. This auxiliary electrode 7 extends along the outer surface of the discharge vessel 2 to the pinch seal part 9.
According to this embodiment, the lead 10 is welded to the auxiliary electrode 7 on the pinch seal part 9 so that the weld (glass solder) 11 does not protrude largely in the thickness direction between the plane face parts 3, 3 of the discharge vessel 2. In some cases, the glass solder may be accommodated within the thickness range, in which case the thickness of the lamp base (see
While the auxiliary electrode 7 is illustrated as narrower than the external electrode 5 in this embodiment, the auxiliary electrode 7 need not necessarily be narrower, and may have the same width, for example, as the external electrode 5.
Moreover, the solid electrode 6, which is provided at the end of the external electrode 5 in the embodiment of
As described above, according to the present invention, an auxiliary electrode is provided to an end portion of the external electrode that is provided on a plane face part of the discharge vessel, and a lead is connected to the auxiliary electrode in a region where the distance between the external electrodes is reduced. Therefore, the lead and its weld do not protrude from the plane face part largely in the thickness direction, which provides the effect of preventing the lamp base that covers the lead and weld from protruding more than the thickness of the discharge vessel as much as possible.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-129309 | Jul 2018 | JP | national |
This application is a continuation application of U.S. patent application Ser. No. 17/257,268, filed on Dec. 30, 2020, which is the U.S. National Phase of International Application No. PCT/JP2019/025322, filed on Jun. 26, 2019, which claims priority to and the benefit of Japanese Patent Application No. 2018-129309, filed on Jul. 6, 2018, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17257268 | Dec 2020 | US |
| Child | 17736279 | US |
