EP0668605A2 - Lampe à décharge à basse pression sans électrodes - Google Patents

Lampe à décharge à basse pression sans électrodes Download PDF

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Publication number
EP0668605A2
EP0668605A2 EP95100561A EP95100561A EP0668605A2 EP 0668605 A2 EP0668605 A2 EP 0668605A2 EP 95100561 A EP95100561 A EP 95100561A EP 95100561 A EP95100561 A EP 95100561A EP 0668605 A2 EP0668605 A2 EP 0668605A2
Authority
EP
European Patent Office
Prior art keywords
cavity portion
top surface
lamp
discharge lamp
mantle
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.)
Ceased
Application number
EP95100561A
Other languages
German (de)
English (en)
Other versions
EP0668605A3 (fr
Inventor
Lászlo Balázs
Kenneth James Downton
Steven John Everest
Gábor Sajo
Judit Szigeti
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.)
Tungsram Rt
Original Assignee
Tungsram Rt
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 Tungsram Rt filed Critical Tungsram Rt
Publication of EP0668605A2 publication Critical patent/EP0668605A2/fr
Publication of EP0668605A3 publication Critical patent/EP0668605A3/fr
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/70—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr
    • H01J61/76—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a filling of permanent gas or gases only
    • 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
    • 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
    • H01J65/048—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 an excitation coil

Definitions

  • the invention relates to an electrodeless low-pressure discharge lamp comprising a discharge vessel made from a light-transmitting material and having a bulb portion and a tubular cavity portion sealed in a gas-tight manner, the discharge lamp comprising furthermore an induction coil placed in the cavity portion, and a base member providing for electrical connection with the terminals of the coil and for fixing the lamp and for outer electrical contact where the discharge vessel contains a noble gas fill and additive material and its wall is provided with phosphor-containing coating.
  • This type of an electrodeless low-pressure discharge lamp is, e.g. described in US Patents No.5 111 117 and No. 4 010 400.
  • the top surface of the tubular cavity portion containing the induction coil is formed as a plane surface perpendicular to the mantle surface of the tubular cavity portion.
  • the coating layers such as the reflective, protective and phosphor layers can be applied to the right-angle juncture of these surfaces by using a troublesome manufacturing process only, and, in addition these layers will have poor adhesion, may drop off and having fallen on the bulb portion of the discharge vessel may result in a lamp illuminating with uneven light distribution. Together with this, the mercury in the discharge vessel can react with the sodium of the glass surface left uncovered.
  • This solution has a further disadvantage that the cavity portion forms a relatively sharp-contoured shadow on the surface of the discharge vessel.
  • the top surface of the cavity portion is a hemisphere, a shape being more advantageous in the respect of layer adhesion and shadow forming, ensuring, however a poor utilization of space for the induction coil.
  • the objective of our invention was to provide a solution that resolves both the problems of efficiently utilizing the space for the induction coil and of ensuring good adhesion for the coating layers applied, and, together with this, reduces the extent of shadow forming on the outside surface of the discharge vessel. These could be achieved by shaping appropriately the top surface of the tubular cavity portion and by making an appropriate juncture between the mantle and top surfaces of the cavity portion.
  • an electrodeless low-pressure discharge lamp comprising a discharge vessel made from a light-transmitting material and having a bulb portion and a tubular cavity portion sealed in a gas-tight manner, the discharge lamp comprising furthermore an induction coil placed in the cavity portion, and a base member providing for electrical connection with the terminals of the coil and for fixing the lamp and for outer electrical contact of the lamp and incorporating an electronic circuitry if needed
  • the discharge vessel contains a noble gas fill and additive material and its wall is provided with phosphor-containing coating, and in which the top surface of the tubular cavity portion is formed - over a distance of at least one-third tube radius, beginning at the mantle surface and continuing inwardly towards the lamp axis - so that the theoretical tangential planes of the top surface make an angle exceeding 90 degrees with the lamp axis, and the top surface of the tubular cavity portion has a rounded juncture with the mantle portion of the cavity portion.
  • the cross-section of the tubular cavity portion is rounded with one quarter arc of a full circle at the mantle surface of the cavity portion where the radius of the arc is at least one-third of tube radius of the cavity portion.
  • the top surface may have, e.g. the shape of a horizontal plane.
  • At least a portion of the top surface of the cavity is the mantle of a cone which cone mantle has a rounded juncture with the mantle of the cavity.
  • the juncture of the exhaust tube is made preferably at the vertex of the cone, i.e. at the lamp axis. When this is not the case, also the vertex of the cone has to be rounded to achieve sufficient adhesion of the coating layers.
  • the top surface of the cavity portion is convex when viewed from the inside of the discharge vessel and is formed as a spherical surface where the center of the sphere is placed on the lamp axis and its radius is at least twice the tube radius of the cavity portion.
  • the exhaust tube of the discharge vessel is preferably placed in the center of the top surface of the cavity portion so that it can intrude - in the central portion of the induction coil - into the cavity portion, at least over a part of its length.
  • the layers of the coating are easier to be applied and their adhesion is improved by making use of a slant top surface with an appropriate angle and of a rounded juncture of the top surface with the mantle surface, and, in addition the extent of shadow forming will be reduced together with ensuring efficient utilization of space for the induction coil.
  • the discharge lamp 1 with a power consumption of between 15W and 25W or higher and operated at a frequency of 2MHz and higher, seen in Fig. 1 is composed of a discharge vessel 2 comprising a bulb portion 3 and a cavity portion 4, of a core 7 made from a magnetizable material - ferrite - and a coil 8 surrounding the core 7, both placed in the cavity portion 4 as well as of a base member 5, further of a neck portion 6 joining the discharge vessel 2 and the base member 5.
  • the base member 5 incorporates the electronic circuitry for generating the electromagnetic field, the input terminals of which circuitry are connected with the contacts of the base member 5 serving for the connection to the mains supply and the output terminals, with the terminals of the coil 8.
  • the end portion of the base member 5 is formed to have E27 thread.
  • the neck portion 6 is made from plastic material and is fixed to the bulb portion 3 mechanically or using an adhesive material.
  • the base member 5 is the constricted continuation of the neck portion 6.
  • On the surface of the discharge vessel 2 a coating containing a phosphor also is produced.
  • the inside (or, eventually, outside) surface of the bulb portion 3 is provided with a high-frequency screening layer.
  • a protective layer on which a reflective layer is produced on the inside surface portion of the bulb portion 3 which surface portion is adjacent to the neck portion 6.
  • the innermost layer on the inside surface of the entire bulb portion 3 is a phosphor layer.
  • the cavity portion 4 is coated with protective, reflective and phosphor layers.
  • the screening layer is preferably made from tin dioxide doped with fluorine, antimony or indium.
  • protective layer aluminum oxide, silicon dioxide, etc., and for reflective layer, e.g. titanium dioxide can be used.
  • titanium dioxide can be used for a three-band phosphor several options; an example for this is the following combination; europium- activated yttrium oxide plus cerium- and terbium- activated lanthanum phosphate plus europium-activated barium-magnesium aluminate.
  • other phosphor combinations are also suitable such as those described in US Patent Specification No. 4 357 559 where aluminate phosphors are used instead of the phosphors listed as the second and third ones in our example.
  • the discharge vessel 2 is made, e.g. from magnesia glass, its bulb portion 3 has a maximum diameter of 80mm and its cavity portion 4 has a cylindrical shape with 26mm outside diameter and 1 mm wall thickness, in which cavity portion 4 the mantle surface 11 has a gradual transition juncture - with no line of break - with the hemispherical top surface 10 that is in its central portion perpendicular to the axis t and is connected to the mantle surface 11 with a part of a circular annulus, radius ri of which is half or at least one-third the tube radius r.
  • the discharge vessel 2 is exhausted and filled, e.g. with krypton of 0.3 torr pressure and with a mercury-containing additive, e.g. indium-bismuth amalgam with some 3 atomic per cent mercury, via the exhaust tube 12.
  • the tubular cavity portion 4 may also be formed in the way shown in Fig. 2 where a portion of the top surface 10 is a cone mantle that has a juncture with the exhaust tube 12 at the vertex of the cone being at the lamp axis t.
  • the top surface 10 has a rounded juncture with the mantle surface 11.
  • the angle a made by the theoretical tangential planes s with the axis t does not exceed 120 degrees.
  • a further embodiment of the cavity portion 4 suitable for the discharge lamp 1 is seen.
  • the top surface 10 of the cavity portion 4 is convex when viewed from the inside of the discharge vessel 2 and is formed as a spherical surface where the center of the sphere is placed on the lamp axis t and its radius R is at least twice the tube radius r.
  • the theoretical planes s placed on the top surface 10 make - adjacent to the mantle surface 11, at least over a distance of one-third the tube radius r from the mantle surface 11 - an angle exceeding 90 degrees with the lamp axis t.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
EP95100561A 1994-02-17 1995-01-17 Lampe à décharge à basse pression sans électrodes. Ceased EP0668605A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
HU9400450 1994-02-17
HU9400450A HU214131B (en) 1994-02-17 1994-02-17 Low-pressure discharge lamp without electrode

Publications (2)

Publication Number Publication Date
EP0668605A2 true EP0668605A2 (fr) 1995-08-23
EP0668605A3 EP0668605A3 (fr) 1997-03-26

Family

ID=10984834

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95100561A Ceased EP0668605A3 (fr) 1994-02-17 1995-01-17 Lampe à décharge à basse pression sans électrodes.

Country Status (4)

Country Link
EP (1) EP0668605A3 (fr)
JP (1) JPH07312207A (fr)
CA (1) CA2142679A1 (fr)
HU (1) HU214131B (fr)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4048541A (en) * 1976-06-14 1977-09-13 Solitron Devices, Inc. Crystal controlled oscillator circuit for illuminating electrodeless fluorescent lamp
JPS5628460A (en) * 1979-08-15 1981-03-20 Mitsubishi Electric Corp High frequency starting device
NL8500738A (nl) * 1985-03-14 1986-10-01 Philips Nv Elektrodeloze lagedrukontladingslamp.
NL8601702A (nl) * 1986-06-30 1988-01-18 Philips Nv Elektrodeloze lagedrukontladingslamp.
US5291091A (en) * 1991-01-25 1994-03-01 U.S. Philips Corporation Electrodeless low-pressure discharge
US5355054A (en) * 1992-01-07 1994-10-11 U.S. Philips Corporation Electrodeless low-pressure discharge lamp having a cooling body with a partitioned vapor channel

Also Published As

Publication number Publication date
HUT70230A (en) 1995-09-28
HU9400450D0 (en) 1994-05-30
EP0668605A3 (fr) 1997-03-26
HU214131B (en) 1997-12-29
CA2142679A1 (fr) 1995-08-18
JPH07312207A (ja) 1995-11-28

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