Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J65/00—Lamps without any electrode inside the vessel; Lamps with at least one main electrode outside the vessel
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J65/00—Lamps without any electrode inside the vessel; Lamps with at least one main electrode outside the vessel
  • H01J65/04—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels
  • H01J65/042—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels by an external electromagnetic field
  • H01J65/046—Lamps in which a gas filling is excited to luminesce by an external electromagnetic field or by external corpuscular radiation, e.g. for indicating plasma display panels by an external electromagnetic field the field being produced by using capacitive means around the vessel
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J61/00—Gas-discharge or vapour-discharge lamps
  • H01J61/02—Details
  • H01J61/24—Means for obtaining or maintaining the desired pressure within the vessel
  • H01J61/26—Means for absorbing or adsorbing gas, e.g. by gettering; Means for preventing blackening of the envelope
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J61/00—Gas-discharge or vapour-discharge lamps
  • H01J61/02—Details
  • H01J61/30—Vessels; Containers
  • H01J61/34—Double-wall vessels or containers

Definitions

• the invention is based on a dielectric barrier discharge lamp with a discharge vessel in coaxial double tube arrangement, i. an inner tube is coaxially disposed within an outer tube. Inner tube and outer tube are connected to each other and form the gas-tight discharge vessel.
• the discharge space enclosed by the discharge vessel thus extends between the inner and outer tubes and is filled with a discharge medium which typically contains one or more noble gases, for example xenon.
• This type of discharge lamp typically has a first electrode disposed inside the inner tube and a second electrode disposed on the outer side of the outer tube. Both electrodes are thus outside the discharge vessel. It is therefore a two-sided dielectrically impeded discharge.
• xenon excimers In a dielectric barrier discharge with, for example, the noble gas xenon as the discharge medium, xenon excimers (Xe2 *) are produced which emit electromagnetic radiation with wavelengths in the region of approx. 172 nm when returning from the excited state to the ground state.
• Impurities for example oxygen or hydrogen, in the discharge medium reduce the efficiency of the useful radiation generation.
• part of the electrical excitation power goes into the unwanted stimulus tion of the atomic and / or molecular components of the impurities.
• the impurities cause some of the excimer to return to the ground state without radiation.
• This type of lamp is used in particular for UV irradiation in process technology, for example for surface cleaning and activation, photolytics, ozone generation, drinking water purification, metallization, and UV curing.
• the term emitter or UV emitter is also common.
• Document EP 0 607 960 A1 discloses a dielectric barrier discharge lamp in coaxial double tube arrangement.
• a getter material is arranged either in a one-sided extension of the annular gap-shaped discharge space (FIGS. 1-3), a flat, circular extension of the discharge vessel (FIG. 4) or in a separate vessel (FIG. 5). which is connected to the discharge space.
• measures are provided to prevent the getter material from inadvertently entering the discharge space, for example by connecting the getter space from the discharge space via a narrowed section of vessel.
• the problem is that parasitic discharges can form in the area of the getter space due to the proximity of the getter space to the discharge space. The parasitic discharges worsen the efficiency of the radiator. Presentation of the invention
• the object of the present invention is to provide a dielectric barrier discharge lamp in coaxial double tube arrangement with improved arrangement of a getter material.
• a dielectric barrier discharge lamp in coaxial double tube arrangement with a discharge vessel comprising an outer tube and an inner tube, wherein the inner tube coaxially disposed within the outer tube, the inner tube and the outer OHrohr gas-tightly connected to each other, whereby between inside and outer tube is formed a discharge space filled with a discharge medium, an outer electrode disposed on the outer side of the outer tube, an inner electrode disposed inside the inner tube, a getter material in contact with the discharge medium, characterized in that the Inner tube is shorter than the outer tube, the inner tube and the outer tube are gas-tightly connected at their respective one end, the outer tube is gas-tightly sealed at its other end, which projects into the outer tube inner tube comprising: a first pipe section - the êtelek in which the inner electrode is arranged, a second tube section - the getter tube - in which the getter material is arranged, a dividing wall which separates the two tube sections in a gastight manner from one another.
• the getter space is limited to a region close to the axis, that is, not arranged in the extension of the annular gap-shaped discharge space.
• a getter tube provided for receiving the getter material coaxially adjoins the inner electrode tube provided for receiving the inner electrode, but is separated from it gas-tight by a partition wall.
• the way from the getter material to the outer electrodes is relatively long. Due to the long path between getter material and electrodes parasitic discharges are avoided or at least significantly reduced. Due to the partition wall between the getter tube and the inner electrode tube, the getter space formed by the getter tube and consequently also the discharge space communicating with the getter space via the getter tube opening are closed to the outside in a gas-tight manner.
• the getter tube can be formed in that the inner tube is extended beyond the length of the inner electrode.
• the tube section provided for receiving the getter material is separated in a gastight manner from the remainder of the inner tube by means of a separately inserted and welded dividing wall.
• the getter tube forming the getter space and the inner electrode tube receiving the inner electrode are functionally different and separated by the partition portions of the same one-piece inner tube.
• the getter tube may be formed by a separate tube which adjoins the end of the inner electrode tube projecting into the outer tube, ie the inner tube in this case comprises two separate tube tubes. parts: namely the inner electrode tube and the getter tube.
• the two tube parts gas-tight separating partition is formed by a corresponding gas-tight closed end of one of the two tube parts. That is, the partition wall is formed for example by the gas-tight closed end of the inner electrode tube (8), to which the getter tube is attached and thus connected gas-tight.
• the getter tube can first be closed off at one end and then attached and connected to the open end of the inner electrode tube with this closed end.
• the diameter of the inner electrode tube and the diameter of the getter tube may be the same or different.
• the getter as it may also be advantageous to taper the getter tube in the direction of opening.
• the length of the getter tube in the axial direction is adjusted so that a sufficient amount of getter material can be absorbed.
• the getter tube should not be too long, otherwise the radiating portion - this extends only to the area with the inner electrode - based on the total length of the radiator is reduced too much. In practice, depending on the total length of the radiator, lengths in the range between approximately 0.5 cm and 5 cm have proven suitable for the getter tube.
• the getter material may for example be applied to at least a part of the inner surface of the getter tube, for example by barium vapor deposition.
• the getter material can also be attached to the getter tube in other ways. orders to be clamped, for example in strip form in Getterrohr or the like.
• other suitable getter materials come into consideration, for example, porous or powdery oxides, nitrides and carbides and titanium, tantalum, aluminum, zirconium and combinations thereof.
• the diameter of the opening of the getter tube is equal to or greater than the distance between the outside of the inner tube and the inside of the outer tube defining the distance of the discharge.
• the retaining disk in order not to impair the exchange of the discharge medium and consequently the getter effect, the retaining disk must have corresponding openings, for example bores, slots or the like.
• Fig. Ib is a cross-sectional view of the lamp of Fig. Ia along the section line AB.
• the figures Ia, Ib show in a highly schematic representation of a longitudinal section and a cross section along the section line AB of an embodiment of the dielectric barrier discharge lamp according to the invention 1.
• the elongated discharge vessel of the lamp 1 consists of an outer tube 2 and an inner tube 3 in coaxial double tube arrangement , whereby the longitudinal axis L of the discharge vessel is defined.
• the typical length of the outer tube 2 is depending on the application between about 10 and 250 cm.
• the outer tube 2 has a typical outer diameter of 44 mm and a wall thickness of 2 mm.
• the inner tube 3 has a typical outer diameter of 20 mm and a wall thickness of 1 mm.
• Both tubes 2, 3 consist of UV radiation permeable quartz glass.
• the discharge vessel is closed at its two front sides in such a way that an elongate, annular-gap-shaped discharge space 4 is formed.
• the discharge vessel has at one end a suitably shaped, annular vessel section 5, which connects there the corresponding ends of the inner and outer tubes.
• the discharge vessel is closed with a circular vessel section 6, which adjoins there to the corresponding end of the outer tube 2.
• a pumping tube (not shown) attached, with the help of the discharge space. 4 first evacuated and then filled with 15 kPa xenon as a discharge medium. Then the pump tube is melted off.
• the inner tube 3 ends at a distance a of about 1 cm in front of the circular vessel section 6 at the end of the outer tube 2.
• the inner tube 3 consists of a first functional section, which serves to receive an inner electrode 7, the inner electrode tube 8.
• a second functional section which serves to receive a getter material as 9, the getter tube 10.
• inner electrode tube 8 and getter tube 10 are separated by a partition wall 11. This partition 11 also closes off the discharge vessel in this region of the inner tube 3 gas-tight.
• the getter tube 10 is open, so that the discharge medium from the discharge space 4 can get into the getter tube 10 and come into contact with the getter material 9.
• the getter material 9 is made of barium and is evaporated on the inside of the getter tube 10 including the facing side of the partition wall 11.
• the length d of the getter tube 10 is about 1 cm.
• the inner diameter D is about 18 mm and is thus greater than the defined by the distance between the outside of the inner tube 3 and the inside of the outer tube 2 impact distance G, which is about 10 mm.
• a wire mesh 12 is wound, which forms the outer electrode of the lamp 1.
• the inner electrode 7 is formed as a slotted metal tube and consists of a 0.1 mm thick metal sheet, preferably VA sheet.
• the holding plate is provided with suitable openings, for example holes, slots, etc.
• the radiator can be provided with a base at least at one end, preferably at the end with the getter chamber, or at both ends (not shown).

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Electromagnetism (AREA)
• Discharge Lamp (AREA)
• Vessels And Coating Films For Discharge Lamps (AREA)

Applications Claiming Priority (1)

Publications (2)

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• 2008
  • 2008-07-15 US US12/737,405 patent/US8174191B2/en not_active Expired - Fee Related
  • 2008-07-15 KR KR1020117003525A patent/KR101216481B1/ko active Active
  • 2008-07-15 AT AT08775080T patent/ATE545947T1/de active
  • 2008-07-15 CN CN2008801302459A patent/CN102084456B/zh active Active
  • 2008-07-15 JP JP2011517760A patent/JP5165108B2/ja not_active Expired - Fee Related
  • 2008-07-15 EP EP08775080A patent/EP2297772B1/fr active Active
  • 2008-07-15 WO PCT/EP2008/059220 patent/WO2010006642A1/fr not_active Ceased
• 2009
  • 2009-07-13 TW TW98123604A patent/TWI467630B/zh active

Non-Patent Citations (1)

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