US3678315A - Low-pressure sodium vapor discharge lamp - Google Patents

Low-pressure sodium vapor discharge lamp Download PDF

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Publication number
US3678315A
US3678315A US95435A US3678315DA US3678315A US 3678315 A US3678315 A US 3678315A US 95435 A US95435 A US 95435A US 3678315D A US3678315D A US 3678315DA US 3678315 A US3678315 A US 3678315A
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US
United States
Prior art keywords
lamp
discharge tube
sodium
indium
low
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.)
Expired - Lifetime
Application number
US95435A
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English (en)
Inventor
Gustaaf Adolf Wesselink
Thomas Holmes
Arie Jan Rudolf De Kock
Jan Goorissen
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US Philips Corp
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US 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
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3678315A publication Critical patent/US3678315A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H01J61/74—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a main light-emitting filling of difficult vaporisable metal vapour, e.g. sodium
    • 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
    • H01J61/22—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent vapour of an alkali metal
    • 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
    • H01J61/33—Special shape of cross-section, e.g. for producing cool spot

Definitions

  • ABSTRACT A low-pressure sodium vapor discharge lamp subject to high current load employs a predetermined quantity of iridium in addition to the sodium. This enables operation of the lamp under high current conditions without the need of an appendix.
  • the invention relates to a low-pressure sodium vapor discharge lamp provided with a completely closed discharge tube and an outer envelope enveloping this tube, the sodium vapor pressure in the discharge tube during operation of the lamp being lower than that which is associated with the temperature of the discharge tube.
  • a low-pressure lamp is understood to means a lamp whose pressure in the discharge tube is less than 150 Torr.
  • a completely closed discharge tube is understood to mean a discharge tube whose wall does not have apertures so that the contents outer of the discharge place would be in open communication with the space between the liters. envelope and the discharge tube.
  • the number of lumens per liter is understood to mean the the quantity of emitted light divided by the volume of the discharge tube in liters.
  • a sodium light source whose product of lumens per watt and lumens per liter is higher than that of another sodium light source is a light source of a higher quality.
  • the first-mentioned lamp is in principle less suitable for high loads (that is to say, to obtain more lumens per liter) namely because at a larger lamp current the temperature of the envelope of the discharge space, and hence the temperature determining the vapor pressure, increase to more than 260 C, that is to say, the sodium vapor pressure comes in a region which is less favorable for the generation of light.
  • a high current may yield better results because a temperature of the envelope of the discharge space which is more than 260 C may be combined with a sodium vapor pressure associated with a lower temperature than that of the envelope of the discharge space. In that case this vapor pressure may thus have a value which is favorable for the generation of li ht.
  • a known low-pressure sodium vapor discharge lamp of the second kind is described, for example, in the Netherlands Patent application No. 6709573.
  • a discharge tube described in the mentioned patent application is provided with a so called appendix.
  • the temperature of this appendix is slightly less than that of the discharge tube.
  • An advantage of this known lamp is that it may have a high load so that the lumen-per-liter value is comparatively high.
  • a drawback of this known low-pressure sodium vapor discharge lamp is that the manufacture of the discharge space provided with an appendix is fairly complicated. In addition the appendix makes the arrangement rather vulnerable.
  • An object of the present invention is to provide a low-pressure sodium vapor discharge lamp in which the quality product of lumens per watt and lumens per liter is comparatively high but in which the drawback of a great vulnerability of the lamp is obviated.
  • a low-pressure sodium vapor discharge lamp provided with a completely closed discharge tube and an outer envelope enveloping said tube, the sodium vapor pressure in the discharge tube during operation of the "rim lamp being lower than that which is associated with the temperature of the discharge tube, and the temperature of the discharge tube being higher than 260 C is characterized in that the comparatively low vapor pressure is obtained because indium is also present in the discharge tube, the number of indium atoms in percent of the overall number of indium and sodium atoms in the discharge tube being located between 55 percent and 95 percent.
  • the lamp may be provided with one or more layers reflecting infrared light and being present between the inner side of the discharge tube and the outer side of the outer envelope, the permeability of the joint layers to sodium light exceeding percent.
  • a further step, which might be taken optionally in combination therewith, is for example to give the lamps a more compact or more convex shape so that the removal of heat is reduced and hence the desired temperature can be obtained.
  • the condition of an operating temperature of more than 260 C might be alternatively achieved in different manners, for example, with the aid of separate heating sources, or by using the lamp in hot spaces.
  • a low-pressure sodium vapor discharge lamp according to the invention is provided in a substantially closed light fitting.
  • a high temperature of the lamp may be obtained because the cooling can be kept less intensive.
  • the combination of fitting and lamp is particularly suitable to be used for illumination purposes.
  • the reference numeral 1 denotes a U-shaped bent discharge tube, one leg of which is denoted by the reference numeral 2 and the other leg is denoted by the reference numeral 3.
  • An electrode 4 is provided at the end of the leg 2.
  • An electrode 5 is provided at the end of the leg 2.
  • An electrode 5 is provided at the end of the leg 3.
  • An outer envelope denoted by the reference numeral 6 is provided around the discharge tube 1.
  • the space between the discharge tube 1 and the outer envelope 6 is substantially evacuated.
  • the inner side of the outer envelope 6 has a transparent layer 7 of indium oxide. This layer strongly reflects infrared light, but has a great permeability to sodium light.
  • the reference numeral 8 denoted a lamp cap.
  • the discharge tube 1 of the given embodiment contained not only a rare gas but also sodium in a quantity of 37.5 mgs and in addition indium at a weight of 1,250 mgs.
  • the number of indium atoms in the discharge tube in percent of the overall number of indium and sodium atoms in the discharge tube was approximately
  • the described lamp was connected in a manner not further shown through the ballast to an alternating voltage of low frequency, for example, 220 V, 50 Hz.
  • the lamp according to the invention and the lamp not according to the invention have already been adjusted at their so-called G values, namely at their maximum number of lumens per watt.
  • the central column of the table indicates the data of the lamp according to the invention, that is to say, the lamp containing indium, while the extreme right-hand column of the table indicates the situation of the lamp prior to the invention, that is to say, a corresponding lamp whose discharge tube did not contain indium.
  • the first portion of the table relates to the dimensions of the lamp and the discharge tube.
  • the second portion relates to the filling of the discharge tube.
  • the third portion relates to electrical properties such as operation voltage, lamp current, etc. of the lamp according to the invention and of the lamp prior to the invention.
  • Lamp Lamp not arr-cording according to the to the invention invention (containing (without Re indium) iridium) Length of lamp (ems.) 51 M Diameter of lamp (ems) ti. 6 I). 6 Length of the discharge tube (ems) (the 82 it:
  • the table shows that the quality product G X S expressed in lumen per watt-liter in a lamp according to the invention is approximately 35 percent higher than that prior to the invention. This means that the quality of the lamp according to the invention is better. it is true that the luminous efficiency of the lamp according to the invention is fairly low, but this is offset by the fact that the number of lumens per liter of the lamp according to the invention has become extra high.
  • the bulges of the discharge tube 1 shown in the FIGURE serve to maintain sodium and indium evenly distributed in the discharge tube. However there is no appendix which would have made manufacture of the lamp complicated.
  • a low-pressure sodium vapor discharge lamp of the type having a completely closed discharge tube and an outer envelope, and wherein the sodium vapor in the tube during operation is of a lower temperature than that associated with the temperature of the discharge tube and wherein the temperature of the discharge tube is higher than 260 C, wherein the improvement comprises that indium is present within the discharge tube in addition to sodium, the number of indium atoms being between 55 percent and percent of the total number of indium and sodium atoms in the tube.

Landscapes

  • Discharge Lamp (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
US95435A 1969-12-13 1970-12-07 Low-pressure sodium vapor discharge lamp Expired - Lifetime US3678315A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6918745.A NL164423C (nl) 1969-12-13 1969-12-13 Lagedruknatriumdampontladingslamp.

Publications (1)

Publication Number Publication Date
US3678315A true US3678315A (en) 1972-07-18

Family

ID=19808623

Family Applications (1)

Application Number Title Priority Date Filing Date
US95435A Expired - Lifetime US3678315A (en) 1969-12-13 1970-12-07 Low-pressure sodium vapor discharge lamp

Country Status (6)

Country Link
US (1) US3678315A (fr)
BE (1) BE760258A (fr)
DE (1) DE2059577C3 (fr)
FR (1) FR2073525A5 (fr)
GB (1) GB1284789A (fr)
NL (1) NL164423C (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4209726A (en) * 1977-11-02 1980-06-24 U.S. Philips Corporation Low-pressure sodium vapor discharge lamp
EP1187174A3 (fr) * 2000-09-08 2006-03-29 Philips Intellectual Property & Standards GmbH Lampe à décharge dans un gaz à basse pression avec un remplissage gazeux contenant de l'indium
WO2006111902A3 (fr) * 2005-04-20 2007-03-08 Philips Intellectual Property Lampe a decharge gazeuse basse pression comportant des halogenures d'indium et de sodium

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3221198A (en) * 1961-10-04 1965-11-30 Philips Corp Sodium vapor lamp having a tin oxide coating

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3221198A (en) * 1961-10-04 1965-11-30 Philips Corp Sodium vapor lamp having a tin oxide coating

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4209726A (en) * 1977-11-02 1980-06-24 U.S. Philips Corporation Low-pressure sodium vapor discharge lamp
EP1187174A3 (fr) * 2000-09-08 2006-03-29 Philips Intellectual Property & Standards GmbH Lampe à décharge dans un gaz à basse pression avec un remplissage gazeux contenant de l'indium
WO2006111902A3 (fr) * 2005-04-20 2007-03-08 Philips Intellectual Property Lampe a decharge gazeuse basse pression comportant des halogenures d'indium et de sodium

Also Published As

Publication number Publication date
NL164423C (nl) 1980-12-15
DE2059577B2 (de) 1977-07-28
NL6918745A (fr) 1971-06-15
NL164423B (nl) 1980-07-15
DE2059577C3 (de) 1978-04-06
GB1284789A (en) 1972-08-09
DE2059577A1 (de) 1971-06-16
BE760258A (fr) 1971-06-11
FR2073525A5 (fr) 1971-10-01

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