EP0438253A2 - Système de tube à décharge - Google Patents

Système de tube à décharge Download PDF

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Publication number
EP0438253A2
EP0438253A2 EP91300253A EP91300253A EP0438253A2 EP 0438253 A2 EP0438253 A2 EP 0438253A2 EP 91300253 A EP91300253 A EP 91300253A EP 91300253 A EP91300253 A EP 91300253A EP 0438253 A2 EP0438253 A2 EP 0438253A2
Authority
EP
European Patent Office
Prior art keywords
discharge tube
tube
launcher
electrically conductive
conductive material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91300253A
Other languages
German (de)
English (en)
Other versions
EP0438253A3 (en
Inventor
Neil Anthony Linden-Smith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EMI Group Ltd
Original Assignee
Thorn EMI PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thorn EMI PLC filed Critical Thorn EMI PLC
Publication of EP0438253A2 publication Critical patent/EP0438253A2/fr
Publication of EP0438253A3 publication Critical patent/EP0438253A3/en
Withdrawn legal-status Critical Current

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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
    • 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

Definitions

  • a first aspect of the present invention provides a method of manufacturing a discharge tube arrangement including the steps of :
  • a second aspect of the present invention provides a discharge tube arrangement comprising a discharge tube containing a fill and a launcher surtable, when energised with radio frequency (r.f.) power, for exciting surface waves in the discharge tube, the launcher including an inner tube and an outer tube coaxial with said inner tube ;
  • r.f. radio frequency
  • said inner tube comprises a coating of electrically conductive material applied around and onto a part of the external surface of the discharge tube.
  • a discharge tube arrangement as disclosed in eg our copending European Patent Application No.89308876.5, comprises a discharge tube 20 mounted in a launcher 22.
  • the discharge tube 20 is formed of a light-transmissive, dielectric material, such as glass, and contains a fill 24 of a noble gas, such as argon and an ionizable material, such as mercury.
  • the thickness of the electrically conductive material is of the order of millimetres, or less, depending on the construction method used.
  • an oscillating electric field having a frequency typically in the range of from 1MHz to 1GHz, is set up inside the launcher 22. At the first and second gaps 32, 33, this electric field is parallel to the longitudinal axis of the discharge tube 20. If sufficient power is applied, the consequent electric field produced in the gas fill 24 is sufficient to ionise the mercury to create a discharge through which an electromagnetic surface wave may be propagated in a similar manner to the arrangement of EP 0225753A. Accordingly, the launcher 22 powered by the r.f.
  • power generator 34 creates and sustains a discharge in the fill - the length and brightness of the discharge depending, inter alia, on the size of the discharge tube 20 and the power applied by the r.f. power generator 34. Such a discharge tube arrangement may therefore be used as a light source.
  • the first gap 32 and the second gap 33 each extend axially from respective ends of the inner tube 26, respectively to the first plate 30 and to the second plate 31.
  • the discharge tube 20 extends from one end of the launcher 22 and so the first gap 32 is effective as a launching gap to create a discharge.
  • the second gap 33 complements the effect of the first gap 32 and is advantageously larger than the first gap 32.
  • FIG. 2 shows an electrodeless discharge tube 40 containing a fill 42. Coated onto the external surface of the discharge tube 40, near one end, is a band 44 of aluminium. A 3-turn helix 46, also coated onto the external surface of the discharge tube 40, extends therealong.
  • a variety of methods may be used to apply the coatings of electrically conductive material onto the external surface of the discharge tube 40.
  • the discharge tube 40 is masked with tape to produce a stencil, leaving exposed the surfaces to be coated.
  • the masked discharge tube is then placed in a vacuum coating chamber and a tungsten filament is used to evaporate aluminium from lengths of aluminium wire onto the discharge tube.
  • the helix 46 is applied as silver conducting paint.
  • the discharge tube had a length of 120 mm and a diameter of 13 mm.
  • the axial length of the band was 20 mm and the 3-turn helix had a pitch of 30 mm.
  • an outer part of a launcher without the inner tube is constructed.
  • the coated discharge tube is inserted into the launcher outer part and an electrical connection is made to the band 44 for the supply of r.f. power.
  • the electrical connection may include a spring-loaded contact or a wire ring to make contact with the band 44.
  • the band 44 is then effective as the inner tube of a launcher.
  • the outer part of the launcher may be similar to that of Figure 1 or may be as shown in Figure 3.
  • Discharge tube arrangements including a coated discharge tube as described with reference to Figure 2 have been tested.
  • the band of aluminium was found to be satisfactorily effective as the inner tube of the launcher.
  • the silver painted helix had no measurable effect on the total light output of the discharge tube arrangement and this was believed to be due to its relatively high resistance (around 200 ) though it is envisaged that this can be improved.
  • the aluminium helix which had a resistance of less than 1 , produced an increase in total light output similar to the increase effected by a copper wire helix wound tight to the discharge tube.
  • Figure 4 shows the effect of a 5 turn copper helix structure wound tight to the discharge tube wall on the total light output of a discharge tube arrangement operated at 129 MHz. The key to the graphs is given below:

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Tubes (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
EP19910300253 1990-01-16 1991-01-14 A discharge tube arrangement Withdrawn EP0438253A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB909000962A GB9000962D0 (en) 1990-01-16 1990-01-16 A discharge tube arrangement
GB9000962 1990-06-22

Publications (2)

Publication Number Publication Date
EP0438253A2 true EP0438253A2 (fr) 1991-07-24
EP0438253A3 EP0438253A3 (en) 1991-09-25

Family

ID=10669377

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910300253 Withdrawn EP0438253A3 (en) 1990-01-16 1991-01-14 A discharge tube arrangement

Country Status (3)

Country Link
EP (1) EP0438253A3 (fr)
JP (1) JPH04212259A (fr)
GB (1) GB9000962D0 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0989589A4 (fr) * 1998-03-16 2001-10-10 Matsushita Electric Industrial Co Ltd Appareil d'alimentation en energie de decharge sans electrodes et lampe a decharge sans electrodes

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3518299A1 (de) * 1985-05-22 1986-11-27 Paul 7030 Böblingen Gerlach Gasentladungslampe
US4792725A (en) * 1985-12-10 1988-12-20 The United States Of America As Represented By The Department Of Energy Instantaneous and efficient surface wave excitation of a low pressure gas or gases
GB8829251D0 (en) * 1988-12-15 1989-01-25 Emi Plc Thorn A discharge tube arrangement

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0989589A4 (fr) * 1998-03-16 2001-10-10 Matsushita Electric Industrial Co Ltd Appareil d'alimentation en energie de decharge sans electrodes et lampe a decharge sans electrodes
US6518703B1 (en) 1998-03-16 2003-02-11 Matsushita Electrical Industrial Co., Ltd. Electrodeless discharge energy supply apparatus and electrodeless discharge lamp device using surface wave transmission line

Also Published As

Publication number Publication date
GB9000962D0 (en) 1990-03-14
JPH04212259A (ja) 1992-08-03
EP0438253A3 (en) 1991-09-25

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