EP0623946A1 - Low-pressure sodium discharge lamp - Google Patents
Low-pressure sodium discharge lamp Download PDFInfo
- Publication number
- EP0623946A1 EP0623946A1 EP94201152A EP94201152A EP0623946A1 EP 0623946 A1 EP0623946 A1 EP 0623946A1 EP 94201152 A EP94201152 A EP 94201152A EP 94201152 A EP94201152 A EP 94201152A EP 0623946 A1 EP0623946 A1 EP 0623946A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- coating
- discharge vessel
- extends
- pinched seal
- 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.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/36—Seals between parts of vessels; Seals for leading-in conductors; Leading-in conductors
- H01J61/366—Seals for leading-in conductors
- H01J61/368—Pinched seals or analogous seals
Definitions
- the invention relates to a low-pressure sodium discharge lamp comprising: a discharge vessel which is sealed in a vacuumtight manner and has a filling comprising sodium and rare gas; electrodes arranged in the discharge vessel and each connected to at least one respective current conductor which issues to the exterior through a respective pinched seal, wherein the current conductors each have a first coating of borate glass which extends from within the relevant pinched seal to inside the discharge vessel, and in contact with said coating a second, lime glass coating which extends to outside the discharge vessel; and evacuated outer bulb which is provided with an IR reflection filter and which surrounds the discharge vessel.
- the coatings have a butt joint which lies inside the relevant pinched seal.
- the first coating is resistant to sodium. This coating protects the current conductors against electric contact with liquid or solid sodium which could deposit against the pinched seal. The discharge arc could apply itself to the sodium if the coating were absent, which would lead to violent reactions and damage to the current conductor and the pinched seal.
- the second coating is thicker than the first one and absorbs forces which result from the difference between the coefficients of thermal expansion of the discharge vessel and the current conductors.
- this object is achieved in that the first coating extends through the entire pinched seal and is enveloped by the second coating in the pinched seal.
- the low-pressure sodium discharge lamp has a discharge vessel 1 which is sealed in a vacuumtight miner and contains a filling comprising sodium and rare gas.
- Electrodes 2 are arranged in the discharge vessel, each connected to at least one respective current conductor 3 which issues to the exterior through a respective pinched seal 4.
- each electrode has two current conductors.
- the current conductors 3 each have a first coating 5 of borate glass which extends from the relevant pinched seal 4 to inside the discharge vessel 1, and in contact with the said coating 5 a second coating 6 of lime glass which extends to outside the discharge vessel.
- An evacutated outer bulb 8 provided with an IR reflection filter 7 surrounds the discharge vessel and carries a lamp cap, for example, a bayonet cap 10.
- the first coating 5 extends through the entire pinched seal 4 and is enveloped by the second coating 6 in the pinched seal.
- Table 1 (1),(6) (5) (1') SiO2 63.3 5.6 5.7 B2O3 0.8 17.2 18.5 Al2O3 4.7 8.8 9.2 Na2O 17.1 K2O 0.7 0.16 MgO 3.1 5.1 5.0 CaO 4.7 10.3 10.0 BaO 5.2 50.4 50.4 SrO 0.9 1.1 ZrO2 1.5 SO3 0.07 remainder 0.33 0.04 0.1 (1') borate glass on discharge vessel
- each electrode 2 has two current conductors 3, for example made of CrNiFe, each with an individual first 5 and individual second coating 6.
- the discharge vessel 1 is made of lime glass and has a layer of borate glass at its inner surface in order to make the discharge vessel resistant to sodium.
- the outer bulb has an IR reflection filter, for example of tin-doped indium oxide, at its innner surface.
- the lamp in the drawing has a first coating of borate glass which extends throughout the relevant pinched seal from inside the discharge vessel. It is favourable for the coating to extend to outside the discharge vessel so as to have manufacturing tolerances available.
- the second coating of lime glass may be made, for example, of the same glass as the discharge vessel. The presence of this coating is nevertheless visible, inter alia because it projects from the pinched seal.
- the lamp of the type shown continued to burn after 9000 hours at a 125 kHz high-frequency supply without cracks becoming observable.
- lamps with cracks were found after 2000 hours already upon operation under identical circumstances.
- One fourth of the number of lamps exhibited cracks after 5000 hours.
- the compositions of the glasses used are given in % by weight in Table 1.
Landscapes
- Vessels And Coating Films For Discharge Lamps (AREA)
Abstract
Description
- The invention relates to a low-pressure sodium discharge lamp comprising:
a discharge vessel which is sealed in a vacuumtight manner and has a filling comprising sodium and rare gas;
electrodes arranged in the discharge vessel and each connected to at least one respective current conductor which issues to the exterior through a respective pinched seal, wherein the current conductors each have a first coating of borate glass which extends from within the relevant pinched seal to inside the discharge vessel, and in contact with said coating a second, lime glass coating which extends to outside the discharge vessel;
and evacuated outer bulb which is provided with an IR reflection filter and which surrounds the discharge vessel. - Such a low-pressure sodium discharge lamp is known from US 4,783,612.
- In the known lamp, the coatings have a butt joint which lies inside the relevant pinched seal.
The first coating is resistant to sodium. This coating protects the current conductors against electric contact with liquid or solid sodium which could deposit against the pinched seal. The discharge arc could apply itself to the sodium if the coating were absent, which would lead to violent reactions and damage to the current conductor and the pinched seal.
The second coating is thicker than the first one and absorbs forces which result from the difference between the coefficients of thermal expansion of the discharge vessel and the current conductors. - The construction of the known lamp was found to be reliable in the case of operation at mains frequency. With high-frequency operation, however, cracks arise in the pinched seal after a few thousand hours already, leading to lamp leaks and thus to the end of lamp life.
- It is an object of the invention to provide a low-pressure sodium discharge lamp of the kind described in the opening paragraph which is of a construction which is reliable also in the case of high-frequency operation.
- According to the invention, this object is achieved in that the first coating extends through the entire pinched seal and is enveloped by the second coating in the pinched seal.
- It is assumed that the damage to the known lamp operated at high frequency is caused by the higher electrical resistance which the current conductors have upon high-frequency operation, because they conduct the current substantially only along their surfaces in that case. The current conductors and the pinch then assume higher temperatures.
- It was a surprise to find that the lamp according to the invention can be operated for thousands of hours at high frequency without cracks appearing in the pinched seal.
- An embodiment of the low-pressure sodium discharge lamp according to the invention is shown in the drawing, in which
- Fig. 1 shows a lamp in side elevation, partly in longitudinal section; and
- Fig. 1a shows a detail from Fig. 1 in cross-section on an enlarged scale.
- In the drawing, the low-pressure sodium discharge lamp has a discharge vessel 1 which is sealed in a vacuumtight miner and contains a filling comprising sodium and rare gas.
-
Electrodes 2 are arranged in the discharge vessel, each connected to at least one respectivecurrent conductor 3 which issues to the exterior through a respective pinched seal 4. In the lamp shown, each electrode has two current conductors. Thecurrent conductors 3 each have afirst coating 5 of borate glass which extends from the relevant pinched seal 4 to inside the discharge vessel 1, and in contact with the said coating 5 a second coating 6 of lime glass which extends to outside the discharge vessel. - An evacutated
outer bulb 8 provided with an IR reflection filter 7 surrounds the discharge vessel and carries a lamp cap, for example, abayonet cap 10. - The
first coating 5 extends through the entire pinched seal 4 and is enveloped by the second coating 6 in the pinched seal.Table 1 (1),(6) (5) (1') SiO₂ 63.3 5.6 5.7 B₂O₃ 0.8 17.2 18.5 Al₂O₃ 4.7 8.8 9.2 Na₂O 17.1 K₂O 0.7 0.16 MgO 3.1 5.1 5.0 CaO 4.7 10.3 10.0 BaO 5.2 50.4 50.4 SrO 0.9 1.1 ZrO₂ 1.5 SO₃ 0.07 remainder 0.33 0.04 0.1 (1') borate glass on discharge vessel - In the lamp shown, each
electrode 2 has twocurrent conductors 3, for example made of CrNiFe, each with an individual first 5 and individual second coating 6. The discharge vessel 1 is made of lime glass and has a layer of borate glass at its inner surface in order to make the discharge vessel resistant to sodium. The outer bulb has an IR reflection filter, for example of tin-doped indium oxide, at its innner surface. - The lamp in the drawing has a first coating of borate glass which extends throughout the relevant pinched seal from inside the discharge vessel. It is favourable for the coating to extend to outside the discharge vessel so as to have manufacturing tolerances available. The second coating of lime glass may be made, for example, of the same glass as the discharge vessel. The presence of this coating is nevertheless visible, inter alia because it projects from the pinched seal.
- The lamp of the type shown continued to burn after 9000 hours at a 125 kHz high-frequency supply without cracks becoming observable. Among a group of 106 lamps of the known type, however, lamps with cracks were found after 2000 hours already upon operation under identical circumstances. One fourth of the number of lamps exhibited cracks after 5000 hours. The compositions of the glasses used are given in % by weight in Table 1.
Claims (1)
- A low-pressure sodium discharge lamp comprising:
a discharge vessel (1) which is sealed in a vacuumtight manner and has a filling comprising sodium and rare gas;
electrodes (2) arranged in the discharge vessel and each connected to at least one respective current conductor (3) which issues to the exterior through a respective pinched seal (4), wherein the current conductors (3) each have a first coating (5) of borate glass which extends from the relevant pinched seal (4) to inside the discharge vessel (1), and in contact with said coating (5) a second, lime glass coating (6) which extends to outside the discharge vessel;
an evacuated outer bulb (8) which is provided with an IR reflection filter (7) and which surrounds the discharge vessel,
characterized in that the first coating (5) extends through the entire pinched seal (4) and is enveloped by the second coating (6) in the pinched seal.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP19940201152 EP0623946B1 (en) | 1993-05-03 | 1994-04-27 | Low-pressure sodium discharge lamp |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP93201256 | 1993-05-03 | ||
EP93201256 | 1993-05-03 | ||
EP19940201152 EP0623946B1 (en) | 1993-05-03 | 1994-04-27 | Low-pressure sodium discharge lamp |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0623946A1 true EP0623946A1 (en) | 1994-11-09 |
EP0623946B1 EP0623946B1 (en) | 1997-01-15 |
Family
ID=26133782
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19940201152 Expired - Lifetime EP0623946B1 (en) | 1993-05-03 | 1994-04-27 | Low-pressure sodium discharge lamp |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP0623946B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL1015531C2 (en) * | 1999-06-28 | 2003-12-09 | Koito Mfg Co Ltd | Arc tube with a layer for residual compressive voltage for a discharge lamp unit and method for manufacturing it. |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0129288A1 (en) * | 1983-06-15 | 1984-12-27 | Koninklijke Philips Electronics N.V. | Low-pressure sodium vapour discharge lamp |
-
1994
- 1994-04-27 EP EP19940201152 patent/EP0623946B1/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0129288A1 (en) * | 1983-06-15 | 1984-12-27 | Koninklijke Philips Electronics N.V. | Low-pressure sodium vapour discharge lamp |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL1015531C2 (en) * | 1999-06-28 | 2003-12-09 | Koito Mfg Co Ltd | Arc tube with a layer for residual compressive voltage for a discharge lamp unit and method for manufacturing it. |
Also Published As
Publication number | Publication date |
---|---|
EP0623946B1 (en) | 1997-01-15 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0786797B1 (en) | Arctube for high pressure discharge lamp | |
CA1311012C (en) | Arc tube and high pressure discharge lamp including same | |
US4800320A (en) | Discharge tube for a high pressure metal vapor discharge lamp and a method of manufacturing the same | |
CN100576425C (en) | Cold-cathode fluorescence lamp with molybdenum electrode | |
JP2008124037A (en) | High-pressure discharge lamp | |
US3588577A (en) | Calcia alumina magnesia baria seal composition | |
EP0582426B1 (en) | Alumina, calcia, yttria sealing composition | |
US4199704A (en) | Alumina, calcia, baria, strontia sealing composition and article of manufacture | |
US5498927A (en) | Low-pressure sodium discharge lamp having sealed current conductors with first and second glass coating | |
EP0623946B1 (en) | Low-pressure sodium discharge lamp | |
EP0894335B1 (en) | Glass coating on lead-through conductors in a low-pressure sodium discharge lamp | |
US5288255A (en) | Method of manufacturing a high-pressure discharge lamp with end seal evaporation barrier | |
CA2281091C (en) | Flat spotlight with discharge separated by a dielectric layer and device for the electrodes into the leading discharge area | |
US5208509A (en) | Arc tube for high pressure metal vapor discharge lamp | |
CA2008297A1 (en) | Electrical feed-through connector with glass to aluminum seal | |
US5188554A (en) | Method for isolating arc lamp lead-in from frit seal | |
US3404769A (en) | Cathode-ray tube envelopes | |
EP0341749B1 (en) | Improved arc tube for high pressure metal vapor discharge lamp, lamp including same, and method | |
WO2013073731A1 (en) | Plasma lamp having superior light extraction efficiency | |
EP0212683B1 (en) | Electric lamp | |
EP0615279A1 (en) | Electric lamp | |
CN1391256A (en) | Gas discharge lamp and manufacturing method thereof | |
JPH049750B2 (en) | ||
JP2534085B2 (en) | Flat lighting device | |
CN2328097Y (en) | High voltage discharge lamp with lamp holder |
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: 19950509 |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
17Q | First examination report despatched |
Effective date: 19960209 |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): BE DE FR GB NL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 19970115 Ref country code: BE Effective date: 19970115 |
|
REF | Corresponds to: |
Ref document number: 69401455 Country of ref document: DE Date of ref document: 19970227 |
|
ET | Fr: translation filed | ||
NLV1 | Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: FR Ref legal event code: CD |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: 746 Effective date: 20021025 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: D6 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20030424 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20030430 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20030616 Year of fee payment: 10 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20040427 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20041103 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20040427 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20041231 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |