EP0349045A1 - Haltekonstruktion für Hochdrucknatriumdampf-Entladungsröhren - Google Patents

Haltekonstruktion für Hochdrucknatriumdampf-Entladungsröhren Download PDF

Info

Publication number
EP0349045A1
EP0349045A1 EP89201603A EP89201603A EP0349045A1 EP 0349045 A1 EP0349045 A1 EP 0349045A1 EP 89201603 A EP89201603 A EP 89201603A EP 89201603 A EP89201603 A EP 89201603A EP 0349045 A1 EP0349045 A1 EP 0349045A1
Authority
EP
European Patent Office
Prior art keywords
lamp
discharge device
conductors
high pressure
voltage
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Withdrawn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
EP89201603A
Other languages
English (en)
French (fr)
Inventor
Ray Gibson
Jagannathan Ravi
Joseph Steven Droho
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.)
Philips North America LLC
Original Assignee
US Philips Corp
Philips Electronics North America Corp
North American Philips Corp
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
Priority claimed from US07/212,811 external-priority patent/US4939408A/en
Application filed by US Philips Corp, Philips Electronics North America Corp, North American Philips Corp filed Critical US Philips Corp
Publication of EP0349045A1 publication Critical patent/EP0349045A1/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/82—Lamps with high-pressure unconstricted discharge having a cold pressure > 400 Torr
    • H01J61/825—High-pressure sodium lamps
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/50—Means forming part of the tube or lamps for the purpose of providing electrical connection to it

Definitions

  • the present invention relates to high pressure sodium vapor high intensity discharge lamps, and more particularly to the support structure for a high pressure sodium discharge light source within the lamp.
  • High pressure sodium discharge lamps are comprised of a discharge device mounted in an evacuated outer envelope.
  • the discharge device is typically a ceramic discharge vessel comprised of alumina or sapphire and having conductive terminals for receiving an operating voltage.
  • the conductive terminals are niobium which is used because its coefficient of thermal expansion matches that of alumina and because it is resistant to sodium vapor. Titanium solder is used in connections to the niobium.
  • the outer envelope is evacuated in order to thermally isolate the discharge device, and to avoid reactions of any gas within the outer envelope with the discharge device.
  • Nitrogen which is used in the outer envelope of other types of high intensity discharge lamps, cannot be used in high pressure sodium lamps because of its reactivity with niobium and titanium at high tempera­ture.
  • the evacuated outer envelope of high pressure sodium lamps must be strong and able to withstand severe mechanical impacts without breaking. If the lamp outer envelope were to break, it would implode scattering glass fragments and create a safety hazard.
  • Reflector lamp envelopes have a large face that merges with the envelope side walls at an edge portion having a small radius of curvature.
  • the atmospheric pressure acting on the evacuated envelope causes high stress concentrations in the edge portion and makes it susceptible to breakage.
  • reflector lamps have thin blown glass envelopes and cannot be strengthened by making them substantially thicker.
  • Incandescent reflector lamps having blown glass envelopes uniformly contain a fill gas with an internal pressure of about one atmosphere. With the inner and outer pressures acting on the envelope being approximately equal, no implosion will occur if the envelope breaks and there is less apt to be flying glass fragments.
  • a fill gas has the potential of ionizing and providing a conductive path between the internal lamp parts at the different potentials and electrical breakdown can occur.
  • a high pressure sodium lamp is comprised of an outer envelope containing a rare gas at a pressure of approximately one atmosphere.
  • a metallic reflective layer is disposed on a portion of the outer envelope for defining a reflector.
  • Mounting means mounts the discharge device of the lamp within the outer envelope and is comprised of a pair of conductors for providing a conductive path to the discharge device.
  • the pair of conductors are configured to have a breakdown voltage between them greater than a certain value, and to maintain the breakdown voltage between the conductors and the metallic reflector greater than the certain value.
  • the lamp comprises means within the outer envelope connected across conductors supplying voltage to the discharge device for exhibiting a high impedance below a certain applied voltage and a low impedance above a certain applied voltage.
  • the voltage at which the impedance changes is selected to be lower than the breakdown voltage through the gas atmos­phere within the outer envelope.
  • the lamp comprises thermal control means for controlling the relative thermal dissipation of the ends of the discharge device for rendering its operating voltage insensitive to the orientation of the lamp during the lamp orientation.
  • the thermal control means is comprised of a heat shield on the end of the discharge device closest to the lamp base.
  • the thermal control means is comprised of different length of the electrode mounting means mounting the discharge electrode, resulting in the one electrode being closer to the adjacent end wall than the other electrode to its adjacent end wall.
  • the thermal control means is comprised in that the discharge device has end walls of different thickness. The thicker end wall dissipating more heat than the thinner end wall and thus operating at a lower temperature then the thinner end wall.
  • Fig. 1 illustrates a high pressure sodium reflector lamp having a blown glass envelope.
  • the envelope has a transparent or translucent front dome 1 from which light is emitted during lamp operation.
  • a mid-section 2 converges toward a narrow neck 3 which terminates at the base end of the lamp envelope.
  • a lamp base 4 is mounted on the base end of the envelope opposite the front dome 1.
  • a reflective layer 5 is disposed over at least a portion of the converging mid-section 2 of the lamp envelope. It is illustrated extending up to the edge of the dome 1 of the lamp envelope, and down onto a part of the narrow neck 3.
  • the reflective layer 5 is typically metallic aluminum which is vapor deposited on the inner surface of the envelope.
  • a high pressure sodium discharge device 10 is mounted axially symmetrically within the envelope and emits light which is incident on the reflective layer 5. The convergence of the envelope mid-section 2 having the reflective layer 5 is effective to reflect light from the light source 10 in a forward direction through the dome end of the envelope so as to concentrate the light and give it directivity.
  • the high pressure sodium discharge device 10 has a translucent body 11 and a pair of terminals 12, 13 each extending from a respective end of the tubular body 11. When a sufficiently high voltage is applied across the terminals 12 and 13, an electrical discharge is established between a pair of spaced internal electrodes (not shown) within the tubular body 11 and intense visible light is emitted.
  • the discharge device 10 is mounted within the envelope by a frame structure which also comprises conductors for applying an operating voltage to the dis­charge device.
  • the base end of the envelope is closed by a stem 7 which is terminated at a pinch seal 8.
  • a pair of rigid support conductors 14, 15 emerge from the pinch seal 8 and extend longitudinally of the envelope toward the dome end 1.
  • the shorter conductor 14 has a free end which is connected to the terminal 13 of the discharge device by a conductive link 21.
  • the free end of the longer conductor 15 is attached to the terminal 12 by the conductive link 22.
  • Each of the support conductors 14, 15 extend into the pinch seal 8 and are connected by respective conductive leads to the lamp base 4, in a conventional manner. Consequently, a voltage applied across the lamp base 4 is developed across the terminals 12, 13 of the high pressure sodium discharge device 10 for energizing it to emit light.
  • the outer envelope contains rare gas at a fill pressure of about 700 torr at room temperature.
  • the rare gas pressure is greater than one atmosphere (760 torr), in one example 930 torr. So there is no substantial pressure difference across the wall of the lamp envelope, as the occuring range of pressure diffe­rence is of the same magnitude as barometric variations. Consequently, if the envelope is broken there will be no substantial pressure difference to accelerate glass fragments and cause flying fragments of the broken envelope.
  • the rare fill gas within the outer envelope thus makes it safe to use thin blown glass outer envelopes in high pressure sodium reflector lamps.
  • the higher pressure rare gas fill increases the probability of internal voltage breakdown being caused by the 4,000 volt starting pulse.
  • the metallic components of the discharge device mounting structure are shaped to maximize the distance between the support conductors 14 and 15 that have an electrical potential between them during lamp operation.
  • the discharge device 10 is positioned on the lamp center line, and the short straight conductor 14 is on one side of the center line.
  • the conductor 15 emerges from the pinch seal 8 on the opposite side of the lamp center line, and after a short length 16 it is bent perpendicular to the conductor 14.
  • the section 17 of the conductor 15 extends perpendicularly away from the conductor 14, and is bent to define a portion 18 extending parallel to the conductor 14.
  • the next portion 19 extends away from the imaginary plane defined by the conductor 14 and the portions 16 and 17 of the conductor 15.
  • the next section 20 again extends parallel to the lamp longitudinal direction, and the successive section 21 extends back toward the original line of direction of the section 18.
  • the last section 22 of the conductor 15 extends along the same line of direction as the section 18. This structure allows sufficient separation between the conductors 14 and 15 and at the same time avoids the conductor 15 from coming too close to the reflective layer 5, which is typically a metallic and conductive layer such as aluminum.
  • Section 16 of the conductor 15 is the part that is closest to the conductor 14. This is where electrical breakdown is most likely to occur.
  • a glass sleeve 33 covers the portion of the conductor 14 opposite the section 16 of the conductor 15. The glass sleeve 33 increases the breakdown voltage between the conductors 14 and 15.
  • the gas krypton was used in a reflector lamp having the glass sleeve 33 and did not break down. Thus, krypton fill gas provides a practicable way of eliminating the implosion problem.
  • high pressure sodium reflector lamps were made which were identical except that some had the sleeve and some did not.
  • the lamps had 70 watt HPS discharge devices mounted in an RL-38 outer envelope filled with krypton at a pressure of 700 torr.
  • the space between the conductor 14 and the section 16 of the conductor 15 was eight millimeters.
  • the application of a 4,000 volt one microsecond pulse caused arcing between the conductors 14 and 15, in the lamp without a glass sleeve.
  • no arcing occurred as long as the terminal 13 of the HPS discharge device 10 was at least 13 millimeters from the conductor 15.
  • all metallic parts are configured to eliminate sharp points and edges. Sharp points create regions of electric field concen­tration and may facilitate localized ionization of the rare fill gas which could initiate a breakdown between the conductors 14 and 15.
  • the discharge device is frequently attached to the supporting conductors by thin metallic ribbons or straight rigid rods.
  • connectors 30 and 31 are made from wire having a circular cross section and are wrapped around the respective discharge device terminal and support conductor in the manner shown in Fig. 3. This eliminates the sharp edges or ends inherent in the prior art structure and avoids any attendant reduction in breakdown voltage.
  • the curved connectors 30, 31 increased the breakdown voltage by 1000 peak a.c. volts relative to straight rod connectors.
  • a getter support 40 is attached to the section 22 at the free end of the conductor 15. This position maximizes the distance of the getter support 40 from the conductor 14 and also avoids reducing the internal breakdown voltage of the mounting frame structure.
  • the rare fill gas also contributes to dissipat­ion of heat developed in the discharge device 10 during lamp operation.
  • HPS discharge devices have minimum operating temperatures. If they are not sufficiently heated during operation their internal sodium vapor pressure will be too low and the light output will be substantially reduced.
  • the discharge device 10 is physically smaller than a discharge device for the same wattage used in an evacuated HPS lamp.
  • the lamps described herein have a discharge device lenght of 41.8 millimeters as compared to the standard 48.0 millimeter length, and a 4.0 millimeter inside diameter as compared to the 4.8 millimeter standard. The smaller physical size reduces the area of the discharge device through which heat can transfer to the rare fill gas so that the discharge device operates at the correct temperature even though substantial amounts of thermal energy can be transferred through the rare gas.
  • the smaller HPS discharge device 10 results in a lamp for which the beam spread is substantially determined by the position of the discharge device along the center line of the lamp. This is shown by the data in the following Table I.
  • the beam spread of the lamp can be set between 15 and 96 degrees by selecting the position of the discharge device within an interval of 15 millimeters. This broad range in beam spread was achieved with an RL-38 outer envelope.
  • the RL-38 bulb has a seal length (the distance from the base of the stem 7 to the dome 1) of 130 mm.
  • the mount height is measured from the base of the stem 7 to the center of the discharge device 11.
  • the lamps for which data is reported in Table I had a discharge device 41.8 mm in length, with an arc length of about 21 mm.
  • the HPS discharge device 10 is relatively closer to the dome end of the lamp envelope 1. This results in the lamp voltage being strongly dependent upon the orientation of the lamp during operation.
  • the cooler end of the discharge device 10 When the lamp is operated in a base-up orientation the cooler end of the discharge device 10 will be at the dome end of the discharge envelope. Consequently, the sodium amalgam within the discharge device will condense at that end.
  • the colder end of the discharge device When the lamp is operated in a base-down orientation the colder end of the discharge device will be at the bas end of the discharge device 10 and that is where the sodium amalgam will condense.
  • the lamp voltage In the base-up orientation, the lamp voltage will too high because of excessive reflected heat back onto the end of the discharge device which elevates the discharge device temperature. It was found that for the 70 watt lamp, the lamp voltage was 49.6 volts in the base-down orientation and 62.6 volts in the base-up orientation.
  • the discharge device may be made unsymmetric­al in order to eliminate the lamp voltage sensitivity to lamp operating position.
  • Fig. 4 illustrates an HPS reflector lamp having a discharge device 10′ with a heat reflector 35 at its end closest to the lamp base.
  • the heat reflector is effective for reflecting internally generated heat back into the discharge device 10′ and maintaining the end of the discharge device 10′ with the heat reflector 35 at a higher temperature.
  • Those elements of the lamp shown in Fig. 4, which correspond to the elements of the lamp shown in Fig. 1 have the same reference numerals.
  • FIG. 5 An alternative to the use of a heat reflector is the asymmetrical discharge device 10 ⁇ shown in Fig. 5.
  • a pair of discharge electrodes 36, 37 are mounted inter­nally at the ends of connectors 12 and 13, respectively.
  • the distance from an electrode tip to an end wall of the discharge device 10 affects the end temperature of the discharge device; the shorter the distance the higher the temperature.
  • a discharge device 10 ⁇ with an electrode tip to end wall distance for the electrode 36 of 7.75 millimeters and the tip to wall dimension for the electrode 37 of 7.25 millimeters was used in a reflector lamp with an RL-38 outer envelope. As shown in Table II, the 0.5 millimeter shorter distance reduced the variation in operating voltage to less than one volt. TABLE II Electrode configuration lamp voltage base down lamp voltage base up ⁇ v asymmetrical 48.4 49.2 0.8 symmetrical 49.6 62.6 13.0
  • An asymmetrical discharge device can also be realized with equal electrode tip to end wall distances for both electrodes but with end walls of different thicknesses.
  • the thicker end wall will dissipate more heat than the thinner end wall and thus operate at a lower temperature than the thinner end wall.
  • the lamp shown in Fig. 6 includes an HPS discharge device 50 mounted within a lamp envelope by support conductors 51, 52 in the manner previously described. A voltage across the conductors 51, 52 is the voltage which is applied to the discharge device 50 for operating it.
  • the lamp outer envelope contains the rare gas argon at a pressure of the order of 700 torr.
  • a switching device 60 is incorporated in the lamp to define a circuit path having a selected breakdown voltage which is lower than the breakdown voltage between the conductors 51 and 52.
  • the circuit path is isolated from the argon atmosphere in the lamp envelope and has a normally high impedance. When the voltage between the support conductors 51 and 52 exceeds a certain threshold voltage a low impedance circuit path is established between the conductors 51, 52 through the switching device 60.
  • the switching device 60 is a spark gap device comprised of a non-conductive cylindrical wall 61 and conductive end closures 62, 63 and having an internal chamber.
  • Internal electrodes 64, 65 are each mounted on a respective one of the conductive end closures 62, 63.
  • Lead 66 extends from the conductive end closure 62, and lead 67 extends from the conductive end closure 63.
  • the leads 66 and 67 are each connected to a respective one of the conductors 52, 51 so that the potential applied across the discharge device 50 is also applied across the spark gap device 60.
  • the chamber of the spark gap device 60 has a gas fill selected to establish a particular breakdown voltage.
  • the voltage difference between the conductors 51 and 52 is applied through the leads 66 and 67 to the respective conductive end closures 62 and 63. Consequently, the voltage difference between the conductors 51 and 52 exists between the internal electrodes 64, 65. When that voltage difference exceeds the selected breakdown voltage of the spark gap device 60, the gas fill within the spark gap device 60 ionizes and a discharge or spark occurs between the internal electrodes 64 and 65.
  • the spark gap device 60 has a low impedance and is conductive, and the voltage difference between the conductors 51 and 52 is short circuited before breakdown of the argon fill gas within the lamp outer envelope can occur.
  • the switching device 60 is a self-restoring device and can be repeatedly switched to its low impedance conductive state and each time it will return to its high impedance condition after the applied voltage decreases below its threshold voltage.
  • Fig. 7 illustrates a reflector lamp having a discharge switching device like that incorporated in the lamp of Fig. 6.
  • the controlled and isolated discharge path provided by the switching device is particularly advantageous in a reflector lamp.
  • the reflector lamp includes a reflective layer such as metallic aluminum which is conductive.
  • the metallic reflective layer can provide part of a breakdown path between the conductors 51 and 52. For example, an electrical breakdown could occur through the argon fill gas between the conductor 51 and the reflective layer, and between the reflective layer and the conductor 52.
  • the metallic conductive layer would thus provide part of the breakdown path between the conductors.
  • Fig. 8 illustrates the relationship among the various voltage magnitudes which define the modes of operation of the invention.
  • the starting voltage V s of the discharge device 10 is typically around 2500 volts for a high pressure sodium lamp; the 70 watt discharge device used in the lamps made and discussed herein have a starting voltage of less than 1800 volts.
  • the maximum voltage V max that the lamp should withstand is nominally 4,000 volts.
  • the controlled breakdown voltage V c of the spark gap device is selected to have a value between V s and V max .
  • V s and V max change as the temperature of the lamp increases during lamp operation.
  • the breakdown voltage of the argon gas within the lamp outer envelope decreases. This was an unexpected result because the breakdown voltage should have been independent of pressure at the constant gas density expected in a sealed lamp.
  • the decrease in breakdown voltage was measured in a lamp having an outer envelope filled with argon at 700 torr and a stem like that shown in Fig. 2 but without the glass sleeve 33.
  • the internal breakdown voltage will decrease by about 500 volts to 3500 volts.
  • the internal pressure of the sodium vapor within the discharge device 10 increases substantially and the starting voltage increases.
  • the starting voltage may increase to a value greater than the controlled breakdown voltage V c of the arc gap device.
  • the breakdown voltage V c must therefore be selected less than the lowered maximum voltage V max that the lamp can withstand, but it should be higher than V s so that the lamp can be restarted without having to first cool down completely.
  • a good nominal value for V c is around 3,000 volts.
  • the use of the switching device 60 is not limited to reflector lamps. It can also be applied to high pressure sodium lamps having conventional envelopes but which have a rate gas fill rather than a high vacuum. Such lamps might use the rare gas to limit discharge device material evaporation as discussed above. The problem of internal electrical breakdown through the rare gas could also be solved with the switching device as it is in reflector lamps.

Landscapes

  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Discharge Lamp (AREA)
EP89201603A 1988-06-29 1989-06-19 Haltekonstruktion für Hochdrucknatriumdampf-Entladungsröhren Withdrawn EP0349045A1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US21280388A 1988-06-29 1988-06-29
US21281888A 1988-06-29 1988-06-29
US212811 1988-06-29
US212818 1988-06-29
US212803 1988-06-29
US07/212,811 US4939408A (en) 1988-06-29 1988-06-29 High pressure sodium discharge reflector lamp

Publications (1)

Publication Number Publication Date
EP0349045A1 true EP0349045A1 (de) 1990-01-03

Family

ID=27395789

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89201603A Withdrawn EP0349045A1 (de) 1988-06-29 1989-06-19 Haltekonstruktion für Hochdrucknatriumdampf-Entladungsröhren

Country Status (3)

Country Link
EP (1) EP0349045A1 (de)
JP (1) JP2804090B2 (de)
CA (1) CA1308159C (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4569928B2 (ja) * 2006-05-31 2010-10-27 パナソニック株式会社 金属蒸気放電ランプおよび照明装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4677343A (en) * 1983-11-18 1987-06-30 Thorn Emi Plc Sealed beam lamps

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5224069Y2 (de) * 1972-04-15 1977-06-01
JPS5386879U (de) * 1976-12-17 1978-07-17
JPS6037646A (ja) * 1983-08-09 1985-02-27 Japan Storage Battery Co Ltd 高圧ナトリウムランプ
JPS60147153U (ja) * 1984-03-12 1985-09-30 日本電池株式会社 高圧ナトリウムランプ

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4677343A (en) * 1983-11-18 1987-06-30 Thorn Emi Plc Sealed beam lamps

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, unexamined applications, E field, vol. 4, no. 59, May 2, 1980; THE PATENT OFFICE JAPANESE GOVERNMENT, page 22 E 9 *
PATENT ABSTRACTS OF JAPAN, unexamined applications, E field, vol. 5, no. 171, October 30, 1981; THE PATENT OFFICE JAPANESE GOVERNMENT, page 4 E 80 *
PATENT ABSTRACTS OF JAPAN, unexamined applications, E field, vol. 5, no. 171, October 30, 1981; THE PATENT OFFICE JAPANESE GOVERNMENT, page 5 E 80 *
PATENT ABSTRACTS OF JAPAN, unexamined applications, E field, vol. 7, no. 276, December 9, 1983; THE PATENT OFFICE JAPANESE GOVERNMENT, page 54 E 215 *

Also Published As

Publication number Publication date
JPH0251843A (ja) 1990-02-21
CA1308159C (en) 1992-09-29
JP2804090B2 (ja) 1998-09-24

Similar Documents

Publication Publication Date Title
US4977346A (en) High pressure sodium discharge lamp having gas filled outer envelope
US5955845A (en) High pressure series arc discharge lamp construction with simplified starting aid
US5493167A (en) Lamp assembly with shroud employing insulator support stops
US4970431A (en) High-pressure sodium discharge lamp with fins radially extending from the discharge vessel for controlling the wall temperature of the discharge vessel
US4939408A (en) High pressure sodium discharge reflector lamp
US4431945A (en) High pressure metal vapor discharge lamp
US4506369A (en) High power cesium lamp system for laser pumping
US5838104A (en) Shield for high pressure discharge lamps
US4958103A (en) HID lamp with multiple discharge devices
EP1218922B1 (de) Hochdruckentladungslampe
US4625141A (en) Low wattage metal halide discharge lamp electrically biased to reduce sodium loss
EP0186899B1 (de) Metallhalogenidlampe mit Bogenröhrenschildstütze
EP0349045A1 (de) Haltekonstruktion für Hochdrucknatriumdampf-Entladungsröhren
US4963791A (en) High pressure sodium discharge tube support structure
US5130602A (en) High-pressure gas discharge lamp
US4620125A (en) Low wattage metal halide lamp with inverted domed sleeve
EP0165587B1 (de) Metallhalogenid-Entladungslampe mit Vorrichtung zum Ausgleich der Bogenrohrtemperatur
US4510418A (en) Rapid start fluorescent lamp with a bimetal electrode disconnect switch
EP0145291B1 (de) Sealed-Beam-Lampe
US20030025455A1 (en) Ceramic HID lamp with special frame for stabilizing the arc
EP0160972B1 (de) Mittel zur Verringerung von Alkalimetallverlust
EP0517304A2 (de) Hochdruckgasentladungslampe
US4105929A (en) Shunt triggered flashtube having safety feature
JP3293591B2 (ja) シールドビーム形放電ランプ
EP0492726A1 (de) Hochdrucknatriumlampe mit Reflektor

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): BE DE FR GB NL

17P Request for examination filed

Effective date: 19900628

17Q First examination report despatched

Effective date: 19930210

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: PHILIPS ELECTRONICS NORTH AMERICA CORPORATION

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19940630