WO2005017944A2 - La lampe a vapeur de mercure et a basse pression - Google Patents

La lampe a vapeur de mercure et a basse pression Download PDF

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Publication number
WO2005017944A2
WO2005017944A2 PCT/IB2004/051375 IB2004051375W WO2005017944A2 WO 2005017944 A2 WO2005017944 A2 WO 2005017944A2 IB 2004051375 W IB2004051375 W IB 2004051375W WO 2005017944 A2 WO2005017944 A2 WO 2005017944A2
Authority
WO
WIPO (PCT)
Prior art keywords
discharge
low
lamp
conductive layer
pressure mercury
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
PCT/IB2004/051375
Other languages
English (en)
Other versions
WO2005017944A3 (fr
Inventor
Jan P. Dekker
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.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
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 Koninklijke Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Publication of WO2005017944A2 publication Critical patent/WO2005017944A2/fr
Publication of WO2005017944A3 publication Critical patent/WO2005017944A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • H01J61/72—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a main light-emitting filling of easily vaporisable metal vapour, e.g. mercury
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/12—Selection of substances for gas fillings; Specified operating pressure or temperature
    • H01J61/18—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent
    • H01J61/20—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent mercury vapour
    • 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
    • H01J61/35—Vessels; Containers provided with coatings on the walls thereof; Selection of materials for the coatings

Definitions

  • the invention relates to a low-pressure mercury vapor discharge lamp.
  • the invention also relates to a compact fluorescent lamp.
  • mercury constitutes the primary component for the (efficient) generation of ultraviolet (UV) light.
  • a luminescent layer comprising a luminescent material (for example, a fluorescent powder) may be present on an inner wall of the discharge vessel to convert UV to other wavelengths, for example, to UV-B and UV-A for tanning purposes (sun panel lamps) or to visible radiation for general illumination purposes.
  • Such discharge lamps are therefore also referred to as fluorescent lamps.
  • the ultraviolet light generated may be used for germicidal purposes (UV-C).
  • the discharge vessels of low-pressure mercury vapor discharge lamps are usually circular and comprise both elongate and compact embodiments.
  • the tubular discharge vessel of a compact fluorescent lamp comprises a collection of comparatively short straight parts having a comparatively small diameter, which straight parts are connected together by means of bridge parts or via bent parts.
  • Compact fluorescent lamps are usually provided with an (integrated) lamp cap.
  • the means for maintaining a discharge in the discharge space are electrodes arranged in the discharge space.
  • the low- pressure mercury vapor discharge lamp comprises a so-called electrodeless low-pressure mercury vapor discharge lamp.
  • the designation "nominal operation" is used to refer to operating conditions where the mercury vapor pressure is such that the radiation output of the lamp is at least 80% of that when the light output is a maximum, i.e. under operating conditions where the mercury vapor pressure is an optimum.
  • the "initial radiation output” is defined as the radiation output of the discharge lamp 1 second after switching-on of the discharge lamp
  • the "run-up time” is defined as the time needed by the discharge lamp to reach a radiation output of 80% of that during optimum operation.
  • Low-pressure mercury vapor discharge lamps are known comprising an amalgam. Such discharge lamps have a comparatively low mercury vapor pressure at room temperature.
  • amalgam-containing discharge lamps have the disadvantage that the initial radiation output is also comparatively low when a customary power supply is used to operate said lamp.
  • the run-up time is comparatively long because the mercury vapor pressure increases only slowly after switching on the lamp.
  • low-pressure mercury vapor discharge lamps which comprise both a (main) amalgam and a so-called auxiliary amalgam. If the auxiliary amalgam comprises sufficient mercury, then the lamp has a comparatively short run-up time. Immediately after the lamp has been switched on, i.e. during preheating of the electrodes, the auxiliary amalgam is heated by the electrode so that it comparatively rapidly dispenses a substantial proportion of the mercury that it contains. In this respect, it is desirable that, prior to being switched on, the lamp has been idle for a sufficiently long time to allow the auxiliary amalgam to take up sufficient mercury. If the lamp has been idle for a comparatively short period of time, the reduction of the run-up time is only small.
  • the initial radiation output is (even) lower than that of a lamp comprising only a main amalgam, which can be attributed to the fact that a comparatively low mercury vapor pressure is adjusted in the discharge space by the auxiliary amalgam.
  • An additional problem encountered with comparatively long lamps is that it takes comparatively much time for the mercury liberated by the auxiliary amalgam to spread throughout the discharge vessel, so that after switching-on of such lamps, they demonstrate a comparatively bright zone near the auxiliary amalgam and a comparatively dark zone at a greater distance from the auxiliary amalgam, which zones disappear after a few minutes.
  • low-pressure mercury vapor discharge lamps are known which are not provided with an amalgam and contain only free mercury.
  • These lamps also referred to as mercury discharge lamps, have the advantage that the mercury vapor pressure at room temperature and hence the initial radiation output are comparatively high as compared with amalgam-containing discharge lamps and as compared to discharge lamps comprising a (main) amalgam and an auxiliary amalgam.
  • the run-up time is comparatively short.
  • comparatively long lamps of this type also exhibit a substantially constant brightness over substantially the whole length, which may be attributed to the fact that the vapor pressure (at room temperature) is sufficiently high at the time of switching-on of these lamps.
  • a comparatively large amount of mercury is necessary for the low-pressure mercury vapor discharge lamps known in the art in order to realize a sufficiently long lifetime.
  • a drawback of the known discharge lamps is that they form a burden on the environment.
  • a low-pressure mercury vapor discharge lamp of the kind mentioned in the opening paragraph for this purpose comprises: a discharge vessel with a length L dV and with an internal diameter D ⁇ n , the discharge vessel enclosing, in a gastight manner, a discharge space provided with a inert gas mixture and with mercury, the discharge vessel comprising discharge means for maintaining a discharge in the discharge space, a conductive layer being disposed, the conductive layer at least partially surrounding the discharge in the discharge space and being provided with potential means for applying a potential to the conductive layer, the ratio of the weight of mercury m ⁇ g in the discharge vessel and the product of the internal diameter D m and the length of the discharge vessel Lj v being given by the relation: m •H.g _ C, D, honor X _X wherein C ⁇ 0.01 ⁇ g/mm
  • the advantage of the provision of a conductive layer is that the mercury losses in the vicinity of the (inner) wall of the discharge vessel are reduced.
  • a potential to the conductive layer the migration of alkali metal ions from the glass to the inner surface of the discharge vessel is influenced.
  • the reduction of the quantity of mercury available for the discharge in the discharge space is mainly caused by the exchange of the alkali metal (for example, Na and/or K) and Hg, and by the absorption of mercury by the surface of the discharge vessel facing the discharge space.
  • the alkali metal for example, Na and/or K
  • Hg the alkali metal
  • mercury enters the wall of the discharge vessel, while the alkali metal oxide simultaneously leaves the wall of the discharge vessel.
  • a discharge vessel of a low-pressure mercury vapor discharge lamp according the invention having a ratio of the weight (expressed in ⁇ g) of mercury and the product of the internal diameter (expressed in mm) and the length (expressed in mm) of the discharge vessel which is below 0.01 ⁇ g mm 2 , contains a comparatively low amount of mercury.
  • the mercury content is considerably lower than what is normally provided in known low-pressure mercury vapor discharge lamps.
  • the low-pressure mercury vapor discharge lamp according to the invention operates for certain ambient temperatures as so-called "unsaturated" mercury vapor discharge lamp.
  • the above given relation shows that the amount of mercury mg g in the discharge lamp is proportional to the product of the internal diameter D ln and the length of the discharge vessel L dV . Roughly speaking, the amount of mercury in the discharge lamp is proportional to the size of the internal surface of the discharge vessel.
  • the formula can at least be applied to low-pressure mercury vapor discharge lamps with a diameter of the discharge vessel in a range from approximately 3.2 mm (1/8 inch) to approximately 38 mm (12/8 inch) and for (corresponding) lengths in a range from approximately 10 mm (1/3 foot) to approximately 27-10 2 mm (9 feet) of the discharge vessels.
  • unsaturated or “unsaturated mercury conditions” are used to refer to a low-pressure mercury vapor discharge lamp in which the amount of mercury dosed into the discharge vessel (during manufacture) of the low-pressure mercury vapor discharge lamp is equal to or lower than the amount of mercury needed for a saturated mercury vapor pressure at nominal operation of the discharge lamp:
  • Operating a mercury vapor discharge lamp under unsaturated mercury conditions has a number of advantages. Generally speaking, the performance of unsaturated mercury discharge lamps (light output, efficacy, power consumption, etc.) is independent of the ambient temperature as long as the mercury pressure is unsaturated.
  • Unsaturated lamps combine minimum mercury content with an improved lumen per Watt luminous efficacy performance at elevated temperatures.
  • the performance of unsaturated lamps is compared with that of so-called cold-spot or so-called amalgam low-pressure mercury vapor discharge lamps, the following advantages can be mentioned.
  • the mercury pressure is controlled by a so-called cold-spot temperature somewhere in the discharge vessel.
  • an amalgam mercury discharge lamp the mercury pressure is controlled by means of an amalgam; in a number of such amalgam discharge lamps an auxiliary amalgam is additionally employed.
  • the initial radiation output and the run-up time and ignition voltage of an unsaturated mercury discharge lamp are comparable to those of cold-spot lamps.
  • a preferred embodiment of the low-pressure mercury vapor discharge lamp according to the invention is characterized in that the conductive layer is translucent. By providing a translucent conductive layer, the light output of the low-pressure mercury vapor discharge lamp is not influenced.
  • the conductive layer is transparent.
  • the conductive layer is tin oxide.
  • a preferred embodiment of the low-pressure mercury vapor discharge lamp according to the invention is characterized in that the conductive layer is provided on an outer surface of the discharge vessel.
  • a preferred embodiment of the low-pressure mercury vapor discharge lamp according to the invention is characterized in that the conductive layer is striped or forms a spiral.
  • the conductive layer extends in the form of stripes or in the form of a helix along the length of the discharge vessel.
  • the constant C is in a range of 0.0005 ⁇ C ⁇ 0.005 ⁇ g/mm 2 . In this regime of C the upper limit of the mercury content in the discharge lamp is further reduced.
  • the discharge lamp according to the invention operates as an unsaturated mercury vapor discharge lamp.
  • a preferred embodiment of the low-pressure mercury vapor discharge lamp according to the invention is characterized in that the discharge vessel contains less than approximately 0.1 mg mercury.
  • the discharge vessel contains less than or approximately 0.05 mg mercury (C ⁇ 0.0013).
  • Fig. 1 is a longitudinal sectional view of an embodiment of the low-pressure mercury vapor discharge lamp in accordance with the invention
  • Fig. 2A is a longitudinal view of an embodiment of the low-pressure mercury vapor discharge lamp with a striped conductive layer
  • Fig. 2B is a longitudinal view of an embodiment of the low-pressure mercury vapor discharge lamp with a spiral conductive layer
  • Fig. 3 is a cross-sectional view of an embodiment of a compact fluorescent lamp comprising a low-pressure mercury vapor discharge lamp according to the invention
  • the Figures are purely diagrammatic and not drawn to scale. Notably, some dimensions are shown in a strongly exaggerated form for the sake of clarity. Similar components in the Figures are denoted as much as possible by the same reference numerals.
  • Fig. 1 shows a low-pressure mercury vapor discharge lamp comprising a glass discharge vessel having a tubular portion 11 about a longitudinal axis 2, which discharge vessel transmits radiation generated in the discharge vessel 10 and is provided with a first and a second end portion 12a; 12b, respectively.
  • the tubular portion 11 has a length L dV of 120 cm and an inside diameter Dj n of 24 mm.
  • the discharge vessel 10 encloses, in a gastight manner, a discharge space 13 containing a filling of mercury and an inert gas mixture comprising, for example, argon.
  • a luminescent layer 17 which comprises a luminescent material (for example a fluorescent powder) which converts the ultraviolet (UV) light generated by fallback of the excited mercury into (generally) visible light.
  • a luminescent material for example a fluorescent powder
  • means for maintaining a discharge in the discharge space 13 are electrodes 20a; 20b arranged in the discharge space 13, said electrodes 20a; 20b being supported by the end portions 12a; 12b.
  • Each electrode 20a; 20b is a winding of tungsten covered with an electron- emitting substance, in this case a mixture of barium oxide, calcium oxide, and strontium oxide.
  • Electrode ring (not shown in Fig. 1) is arranged around each electrode 20a; 20b, on which ring a glass capsule for dispensing mercury is clamped.
  • a conductive layer 16 is disposed on an outer surface of the discharge vessel (10).
  • the conductive layer 16 surrounds the discharge in the discharge space 13.
  • the conductive layer 16 is provided with potential means (not shown in Fig. 1) for applying a potential to the conductive layer 16 during operation of the discharge lamp.
  • the conductive layer is made of tin oxide (Sn0 2 ).
  • the electrode 20a; 20b is surrounded by an electrode shield 22a; 22b which is, preferably, made from a ceramic material.
  • the electrode shield is made from a ceramic material comprising aluminum oxide.
  • Particularly suitable electrode shields are manufactured from so-called densely sintered A1 2 0 3 , also referred to as PCA.
  • a potential difference of 100 V is kept between the conductive coating and the discharge in the discharge space.
  • Fig. 2A schematically shows a longitudinal view of an embodiment of the low-pressure mercury vapor discharge lamp with a striped conductive layer 26.
  • Fig. 2B schematically shows a longitudinal view of an embodiment of the low- pressure mercury vapor discharge lamp with a spiral conductive layer 36.
  • Fig. 3 shows a compact fluorescent lamp comprising a low-pressure mercury vapor discharge lamp. Similar components in Fig. 3 are denoted as much as possible by the same reference numerals as in Fig. 1.
  • the low-pressure mercury vapor discharge lamp is in this case provided with a radiation-transmitting discharge vessel 10 having a tubular portion 11 enclosing, in a gastight manner, a discharge space 13 having a volume of approximately 25 cm 3 .
  • the discharge vessel 10 is a glass tube which is at least substantially circular in cross-section and the (effective) internal diameter D; n of which is approximately 10 mm.
  • the tubular portion 11 has a total length L V (not shown in Fig. 3) of 40 cm.
  • the tube is bent in the form of a so-called hook and, in this embodiment, it has a number of straight parts, two of which, referenced 31, 33, are shown in Fig. 2.
  • the discharge vessel further comprises a number of arc-shaped parts, two of which, referenced 32, 34, are shown in Fig. 3.
  • the discharge vessel 10 can, in a preferable embodiment, be closed in a gastight manner by a disc stem.
  • Disc stem technology is quite common for conventional TV manufacturing. By using this technology in compact fluorescent lamps, frit sealing can be applied to close the burners. A melting glass then makes the vacuum-tight connection between burner tube and disc stem. This process occurs typically below 600°C. Because of this lower temperature, the internal ambient can be kept much cleaner than with conventional processing.
  • the side of the tubular portion 11 facing the discharge space 13 is provided with a luminescent layer 17. In an alternative embodiment, the luminescent layer has been omitted.
  • the discharge vessel 10 is supported by a housing 70 which also supports a lamp cap 71 provided with electrical and mechanical contacts 73a, 73b, which are known per se.
  • the discharge vessel 10 is surrounded by a light-transmitting envelope 60 which is attached to the lamp housing 70.
  • the light-transmitting envelope 60 generally has a matt appearance.
  • a conductive layer 16 is disposed on an outer surface of the discharge vessel 10.
  • the conductive layer 16 surrounds the discharge in the discharge space 13.
  • the conductive layer 16 is provided with potential means (not shown in Fig. 3) for applying a potential to the conductive layer 16 during operation of the discharge lamp.

Landscapes

  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)

Abstract

Lampe à vapeur de mercure et à basse pression présentant une chambre de décharge au moins en partie sensiblement cylindrique (10), de longueur Ldv et de diamètre interne Din. La chambre de décharge renferme, d'une manière étanche aux gaz, un volume de décharge (13) contenant un mélange gazeux inerte et du mercure. La chambre de décharge comporte des moyens de décharge (électrodes 20a; 20b) permettant de maintenir une décharge dans le volume de décharge. Une couche conductrice (16) entoure au moins en partie la décharge dans le volume de décharge. La couche conductrice est pourvue d'un moyen permettant d'appliquer un potentiel à cette dernière. Le rapport entre le poids du mercure mHg dans la chambre de décharge et le produit du diamètre interne Din et de la longueur Ldv de la chambre de décharge répond à l'équation (I), dans laquelle C = 0,01 µg/mm2. La lampe de décharge selon l'invention fonctionne dans des conditions non saturées de mercure.
PCT/IB2004/051375 2003-08-14 2004-08-03 La lampe a vapeur de mercure et a basse pression Ceased WO2005017944A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP03102542.2 2003-08-14
EP03102542 2003-08-14

Publications (2)

Publication Number Publication Date
WO2005017944A2 true WO2005017944A2 (fr) 2005-02-24
WO2005017944A3 WO2005017944A3 (fr) 2005-07-28

Family

ID=34178567

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2004/051375 Ceased WO2005017944A2 (fr) 2003-08-14 2004-08-03 La lampe a vapeur de mercure et a basse pression

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WO (1) WO2005017944A2 (fr)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL185639C (nl) * 1980-10-29 1990-06-01 Philips Nv Lagedrukkwikdampontladingslamp.
DE69505783T2 (de) * 1994-08-25 1999-06-02 Koninklijke Philips Electronics N.V., Eindhoven Niederdruckquecksilberdampfentladungslampe
US6107757A (en) * 1997-03-17 2000-08-22 Matsushita Electric Industrial Co., Ltd. Fluorescent lamp operating apparatus
JP2000173537A (ja) * 1998-09-29 2000-06-23 Toshiba Lighting & Technology Corp 低圧水銀蒸気放電灯および照明装置
JP2003515885A (ja) * 1999-11-24 2003-05-07 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ 低圧水銀放電ランプ
WO2003032364A1 (fr) * 2001-10-04 2003-04-17 Koninklijke Philips Electronics N.V. Lampe a vapeur de mercure a basse pression

Also Published As

Publication number Publication date
WO2005017944A3 (fr) 2005-07-28

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