CA1088614A - Fluorescent lamps - Google Patents
Fluorescent lampsInfo
- Publication number
- CA1088614A CA1088614A CA349,142A CA349142A CA1088614A CA 1088614 A CA1088614 A CA 1088614A CA 349142 A CA349142 A CA 349142A CA 1088614 A CA1088614 A CA 1088614A
- Authority
- CA
- Canada
- Prior art keywords
- glass
- lamp
- portions
- flare
- wires
- 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
Links
Abstract
TITLE: IMPROVEMENTS IN FLUORESCENT LAMPS
ABSTRACT OF THE DISCLOSURE:
The invention relates to electrode mount assemblies for electric discharge and fluorescent lamps. In accordance with the first aspect of the invention the portions of the electrode support wires which are exposed to electron bombardment within the body of the lamp have at least their surface formed of refractory material. The exposed portions may be coated with a refractory material such as boron nitride or made wholly of a refractory metal such as molybdenum. According to a second aspect of the invention relatively cheap soda-lime silicate glass can be used for the end flares of the lamp tubes, because the provision of refractory surfaces on the vulnerable portions of the support wires enables a metal to be chosen for the portions of the wires passing through the glass seal which closely matches the glass in thermal expansion coefficient. The invention improves the life of lamps by reducing end blackening, reduces the incidence of cracks in the punch seal or neck regions of the lamp and may enable cheaper materials to be used for various structural items.
ABSTRACT OF THE DISCLOSURE:
The invention relates to electrode mount assemblies for electric discharge and fluorescent lamps. In accordance with the first aspect of the invention the portions of the electrode support wires which are exposed to electron bombardment within the body of the lamp have at least their surface formed of refractory material. The exposed portions may be coated with a refractory material such as boron nitride or made wholly of a refractory metal such as molybdenum. According to a second aspect of the invention relatively cheap soda-lime silicate glass can be used for the end flares of the lamp tubes, because the provision of refractory surfaces on the vulnerable portions of the support wires enables a metal to be chosen for the portions of the wires passing through the glass seal which closely matches the glass in thermal expansion coefficient. The invention improves the life of lamps by reducing end blackening, reduces the incidence of cracks in the punch seal or neck regions of the lamp and may enable cheaper materials to be used for various structural items.
Description
10~14 The present invention relates to electrical discharge lamps and more especially to mount assemblies for fluorescent lamps.
In electrical discharge lamps of the fluorescent type it is usual for the electrodes to consist of tungsten coils bearing electron-emissive material, each coil being clamped to and carried between two metal supports or lead-wires embedded in a "pinch" seal in a respective glass flare which is sealed into one end of the lamp tube. In order to obtain a reliable seal it is customary to use composite ~Dumet"
support elements and lead glass mounts.
In a lamp running in an alternating current circuit each electrode acts as positive and negative electrode alternately. During the positive part of the cycle the electrode, being bombarded by electrons, gets over-heated and in the past this has led to evaporation of the support wires, causing blackening of the inner surfaces of the lamp tube. The present invention is particularly concerned with reducing or preventing evaporation of the support wires and of so-called "end blackening", and with facilitating the formation of reliable glass-metal seals in leadwire or mount assemblies.
; According to one broad aspect, the invention provides a fluorescent discharge lamp comprising a light-transmitting envelope, electrodes therein, and support wires connected to said electrodes passing through walls of said envelope and sealed therethrough, the improvement comprising coating at least the surfaces of said wires that are exposed within said envelope to electron bombardment with boron nitride.
*
Trademark .
Preferably, this is achieved by coating the surface of the exposed portions of the support wires with refractory material, or by forming the exposed portions of the support wires entirely of refractory metal.
~he invention gives more flexibility ~n the choice - of materials for at least those parts of the support wires located in the region of the se~, which in turn enables a cheaper glass to be employed for the flares. Thus soda-lime glass ca~ be used in conaunction with wires, for example Or nickel-iron alloy, which closely match the glass in coerficient of thermal expansion. Expensive "Dumet"
components used in the prior art can be avoided, while the sod~-lime glass flare~ ca~ be butt-sealed to the ends of the lamp tube instead of the convention~l drop-seal, which ~5 requires the use of lead glass.
Refractory material which is used to co~t the ~urfaces of support wire~ in accordance with the invention preferably has lubricant properties so as to prevent its damaging, by abrasion, machinery used in the assembly of the lamp.
Advantageousl~, where a portion of a support wire i8 composed of refractory metal this portion is welded to the other portion of the wire, which may itself comprise more than one length of wire welded together and may include a metal which facilitates the formation of the required glass-metal seal.
Trademark 0~6 1 4 ~he use of soda-lime silicate gIass for the flares in electrode assemblies in fluorescent lamps represents i~
itself a second important aspect of the ~nventio~.
~lthough soda-lime silicate glass has been generally used for m~k;ng the glass tubes for fluorescent lamps, the flares have been made from lead glass despite the fact that it i9 more expensive than soda-lime glass and that differences in coefficient of expansion between lead glass and soda-lime glass frequently cause "neck cracks" where the flare is sealed i 10 to the tube. It was thought that serious problems would arise from mismatch between metal and ~laæs, and that electrolysis between the leadwires and soda-lime glass would destroy the seal between the wires and the glass and cause air leaks.
Moreoverj it has pre~iously been found that oxide formed on the surface of conventional leadwire materials as they are being sealed i~to the flare results in a poor metal/
glass seal. For this reason "Dumet" wires, which have a ~urface on which oxide does not readily form during the seal-ing operation, have bee~ used for at least that portion of the leadwire passing through the flare, while if a portion of a refractor~ inner support wire is embedded in the glass pinch - and welded to Dumet~ this often gives rise to "pinGh cracks"
in the flare due to differences between the coefficient of expansion of the glass and the refractory wire.
~ccording to this aspect of the present invention a mount assembly for a fluorescent lamp comprises a flare Trademark ~ . :
.. . . ,, . , , . _ .. . . . _, ., ., , _ _ .. . , . , . . . _ ,, . , , . , . . _ !~ f~ 4 1~8~14 made of soda-lime glass and leadwires of which at least the portions passing through the glass have a coefficient of thermal expansion matching that of the glass over most of the temperature range from room temperature to the sealing temperature at which the leadwires are sealed into : the flare.
~he leadwires are preferabiy made from the nic~el-iron alloy referred to above And advantageou~ly have an adherent oxide layer formed on the surface which is sealed.
~nto the gla~s of-the flare.
~he present in~ention will now be described, by way of example, with the aid of the aocompanying drawings ; in which :-~ig. 1 is a diagra~matic view of a fluorescent lamp in accordance with one embodiment of the present invention, ~ig. 2 shows one mount assembly for the lamp of Fig. 1 on an enlarged scale, - Fig. 3 shows a fluorescent lamp embodying a second e~ample of the inve~tion, Fig. 4 shows one mount assembly for the lamp of Fig. 3 on an enlarged scale, and ? ' 4- ' 1()886~ ~
Figs. 5, 6, 7 and 8 are partial views of flares bearing four examples of leadwires suitable for use in connection with the second aspect of the inve~tion.
5 -- ~he fluorescent lamp shown in ~ig. 1 has a glass tube 1 into each end of which is sealed a glass flare 2.
The glass flares (see Fi~. 2) are circular i~
section and have a tapered port~on 3 which at its smaller en~ is integral and coaxial with a parallel sided portion . .
4 where the pinch sePl is formed, ~nd the flares are ~ealed, at the larger end of the tapered portion 3, into the e~ds of the glass tube 1. .
Either one or both (as shown i~ ~ig. 1) of the :
; flares 2 may ha~e an aY~al bore 5 which eztends ~rom the outer end or ends of the flare or flares as a tubulation 6, : through which the lamp may be exhausted and the mercury and the required gas or gas mixture introduced before the bore or bores 5 are closed at their inner end or ends, thereby completely sealing the lamp.
Passing through and sealed into each glass flare 2 ~088~14 4 - i8 a pair of-support ~res or leadwires 7 which extend generally parallel to the flare axis and project from the inner end of the flare. ~t the i~ner end of each leadwire is an inner support clamp portion 8, and an electrode in the form of a coated coil 9 is held between the clamps 8, the coil being substantially perpendicular to the axis of - the lamp.
~he coil 9 is surrounded by a floating shield 10 held in place by a support 11 which is itself attached to the glass flare 2.
~he inner support clamp8 8 and parts of the lead-wires 7 which are subaect to electron bombardment when the lamp is in use ha~e a coati~g 12 (Fig. 2) of boron nitride, a refractory material which also possesses lubricant properties. ~he boron nitride may be applied b~ any suitable method, most co~veniently in the form of a suspension i~ water or org~n;c solvent applied`to the leadwire by such means as spoon dipping, brushing, spraying or drip feeding through a Jet.
~ccording to a second e~ample of the present invention, a fluoresce~t lamp is sho~n in Fig. 3 having a glass tube 1 and glass flares 2 (Fig. 4), similar to those in Figs. 1 and 2, and into which are sealed support wires or leadwires 7.
Each le~dwire 7 has a portion 14 extending through the ~lare 2 and into the space within the lamp, and a portion 15 of refractory metal welded to the i~ner end of 36J~4 the portion 14. The refractory metal portion 15 may extend any aistance along the leadwire 7 from the support clamp 8 up to a point in the leadwire 7 immediately adjacent, but not in contact with, the glass of the flare
In electrical discharge lamps of the fluorescent type it is usual for the electrodes to consist of tungsten coils bearing electron-emissive material, each coil being clamped to and carried between two metal supports or lead-wires embedded in a "pinch" seal in a respective glass flare which is sealed into one end of the lamp tube. In order to obtain a reliable seal it is customary to use composite ~Dumet"
support elements and lead glass mounts.
In a lamp running in an alternating current circuit each electrode acts as positive and negative electrode alternately. During the positive part of the cycle the electrode, being bombarded by electrons, gets over-heated and in the past this has led to evaporation of the support wires, causing blackening of the inner surfaces of the lamp tube. The present invention is particularly concerned with reducing or preventing evaporation of the support wires and of so-called "end blackening", and with facilitating the formation of reliable glass-metal seals in leadwire or mount assemblies.
; According to one broad aspect, the invention provides a fluorescent discharge lamp comprising a light-transmitting envelope, electrodes therein, and support wires connected to said electrodes passing through walls of said envelope and sealed therethrough, the improvement comprising coating at least the surfaces of said wires that are exposed within said envelope to electron bombardment with boron nitride.
*
Trademark .
Preferably, this is achieved by coating the surface of the exposed portions of the support wires with refractory material, or by forming the exposed portions of the support wires entirely of refractory metal.
~he invention gives more flexibility ~n the choice - of materials for at least those parts of the support wires located in the region of the se~, which in turn enables a cheaper glass to be employed for the flares. Thus soda-lime glass ca~ be used in conaunction with wires, for example Or nickel-iron alloy, which closely match the glass in coerficient of thermal expansion. Expensive "Dumet"
components used in the prior art can be avoided, while the sod~-lime glass flare~ ca~ be butt-sealed to the ends of the lamp tube instead of the convention~l drop-seal, which ~5 requires the use of lead glass.
Refractory material which is used to co~t the ~urfaces of support wire~ in accordance with the invention preferably has lubricant properties so as to prevent its damaging, by abrasion, machinery used in the assembly of the lamp.
Advantageousl~, where a portion of a support wire i8 composed of refractory metal this portion is welded to the other portion of the wire, which may itself comprise more than one length of wire welded together and may include a metal which facilitates the formation of the required glass-metal seal.
Trademark 0~6 1 4 ~he use of soda-lime silicate gIass for the flares in electrode assemblies in fluorescent lamps represents i~
itself a second important aspect of the ~nventio~.
~lthough soda-lime silicate glass has been generally used for m~k;ng the glass tubes for fluorescent lamps, the flares have been made from lead glass despite the fact that it i9 more expensive than soda-lime glass and that differences in coefficient of expansion between lead glass and soda-lime glass frequently cause "neck cracks" where the flare is sealed i 10 to the tube. It was thought that serious problems would arise from mismatch between metal and ~laæs, and that electrolysis between the leadwires and soda-lime glass would destroy the seal between the wires and the glass and cause air leaks.
Moreoverj it has pre~iously been found that oxide formed on the surface of conventional leadwire materials as they are being sealed i~to the flare results in a poor metal/
glass seal. For this reason "Dumet" wires, which have a ~urface on which oxide does not readily form during the seal-ing operation, have bee~ used for at least that portion of the leadwire passing through the flare, while if a portion of a refractor~ inner support wire is embedded in the glass pinch - and welded to Dumet~ this often gives rise to "pinGh cracks"
in the flare due to differences between the coefficient of expansion of the glass and the refractory wire.
~ccording to this aspect of the present invention a mount assembly for a fluorescent lamp comprises a flare Trademark ~ . :
.. . . ,, . , , . _ .. . . . _, ., ., , _ _ .. . , . , . . . _ ,, . , , . , . . _ !~ f~ 4 1~8~14 made of soda-lime glass and leadwires of which at least the portions passing through the glass have a coefficient of thermal expansion matching that of the glass over most of the temperature range from room temperature to the sealing temperature at which the leadwires are sealed into : the flare.
~he leadwires are preferabiy made from the nic~el-iron alloy referred to above And advantageou~ly have an adherent oxide layer formed on the surface which is sealed.
~nto the gla~s of-the flare.
~he present in~ention will now be described, by way of example, with the aid of the aocompanying drawings ; in which :-~ig. 1 is a diagra~matic view of a fluorescent lamp in accordance with one embodiment of the present invention, ~ig. 2 shows one mount assembly for the lamp of Fig. 1 on an enlarged scale, - Fig. 3 shows a fluorescent lamp embodying a second e~ample of the inve~tion, Fig. 4 shows one mount assembly for the lamp of Fig. 3 on an enlarged scale, and ? ' 4- ' 1()886~ ~
Figs. 5, 6, 7 and 8 are partial views of flares bearing four examples of leadwires suitable for use in connection with the second aspect of the inve~tion.
5 -- ~he fluorescent lamp shown in ~ig. 1 has a glass tube 1 into each end of which is sealed a glass flare 2.
The glass flares (see Fi~. 2) are circular i~
section and have a tapered port~on 3 which at its smaller en~ is integral and coaxial with a parallel sided portion . .
4 where the pinch sePl is formed, ~nd the flares are ~ealed, at the larger end of the tapered portion 3, into the e~ds of the glass tube 1. .
Either one or both (as shown i~ ~ig. 1) of the :
; flares 2 may ha~e an aY~al bore 5 which eztends ~rom the outer end or ends of the flare or flares as a tubulation 6, : through which the lamp may be exhausted and the mercury and the required gas or gas mixture introduced before the bore or bores 5 are closed at their inner end or ends, thereby completely sealing the lamp.
Passing through and sealed into each glass flare 2 ~088~14 4 - i8 a pair of-support ~res or leadwires 7 which extend generally parallel to the flare axis and project from the inner end of the flare. ~t the i~ner end of each leadwire is an inner support clamp portion 8, and an electrode in the form of a coated coil 9 is held between the clamps 8, the coil being substantially perpendicular to the axis of - the lamp.
~he coil 9 is surrounded by a floating shield 10 held in place by a support 11 which is itself attached to the glass flare 2.
~he inner support clamp8 8 and parts of the lead-wires 7 which are subaect to electron bombardment when the lamp is in use ha~e a coati~g 12 (Fig. 2) of boron nitride, a refractory material which also possesses lubricant properties. ~he boron nitride may be applied b~ any suitable method, most co~veniently in the form of a suspension i~ water or org~n;c solvent applied`to the leadwire by such means as spoon dipping, brushing, spraying or drip feeding through a Jet.
~ccording to a second e~ample of the present invention, a fluoresce~t lamp is sho~n in Fig. 3 having a glass tube 1 and glass flares 2 (Fig. 4), similar to those in Figs. 1 and 2, and into which are sealed support wires or leadwires 7.
Each le~dwire 7 has a portion 14 extending through the ~lare 2 and into the space within the lamp, and a portion 15 of refractory metal welded to the i~ner end of 36J~4 the portion 14. The refractory metal portion 15 may extend any aistance along the leadwire 7 from the support clamp 8 up to a point in the leadwire 7 immediately adjacent, but not in contact with, the glass of the flare
2. Thus it is ensured that the portion 15 Or the leadwire ; 7 that i9 subject to electron bombardment when the lamp i~
in operation is composed of wire formed from refractory metAl. The preferred refractory metals for this purpose are high temperature molybdenum, tantalum, titanium, vanadium and niobium.
The remaining portion 14 of the leadwire may be made from a nickel-iron alloy having a coefficient of expansion matched with that of the glass flare 2, which can be of soda-lime glass and may be butt se~1ed into the end of the tube 1.
Fluorescent lamps as shown in Figs. 1 and 2 which embod~ the second important aspect of the invention have a soda-lime glass tube 1 into the end of which a soda-lime glass flare 2 is butt-sealed at the so-called "neck" 16.
~he exhaust tubulation 6 is also formed of soda-lime glass.
It is in the neck region 16 of conventional tube~
that occasional cracks develop owi~g to thermal expacsion mismatch bet~een the lead glass flare and the soda-lime glass tube and these are eliminated by the use of soda-lime glass for the flare. Chemical reduction of the lead glass during sealing often produces a dark seal in the regio~ 3 and makes quality control inspection difficult, and again this is a~oided or reduced by the use of soda-lime glass at this point.
In ~igs. 5, 6, 7 and 8 the leadwires 7 consist ; respectively of one, two, three and four lengths of wire welded where necessary at points indicated generally by the numeral 17.
~he leadwire shown in ~ig. 5 is of nickel-iron alloy having a coefficient of expansion closely matching that of the soda-lime glass of the flare, so as to eliminate or reduce the possibility of pinch cracks forming in the portion 4 of the flare, and the length 18 of the leadwire has a uniform adherent surface coating of oxide, formed during ~abrication of the electrode mount, which partially dissolves -in the glass when the leadwires are sealed into the flare and thereby improves the seal. Sufficient oxide should be present to pre~ent complete solution in the glass, as this may give a weaker seal. The clamp portion 8 may have a re-fractory coating of boron nitride as already described above.
Fig. 6 shows a two-part leadwire, welded at 17a, of - which the portion 19 passing through the flare is made of nickel-iron alloy and has an adherent oxide coating extending over that portion of the leadwire passing through the pinch region of the flare. The portion 20 of the leadwire forming the inner support wire may be made of refractory metal, or of any other suitable metal with or without a boron nitride coating.
~ig. 7 shows a three-part leadwire welded at 1~ and 17c in which the portion 21 sealed into the pinch section of _g_ 8614 ~i ~he flare is made of Dumet, and the portion 22 making up the inner support part of the leadwire is of nickel-iron alloy, with or without a boron nitride coati~g on the clamp.
~i~. 8 shows a four-part leadwire welded at 17d, 17e and 17f, of which ths portion 23 betwee~ the welds 17d and 17e and sealed into the pinch portion of the flare is made from Dumet while the portion 24 between the welds 17e and 17f is made from nickel-iron alloy and connec~ the length of Dumet with the inner support wire 25 of refractory metal or other suitable metal, with or without a boron nitride coating on the clamp. It is necessary to include the ~
~ickel-iron portion 24 because, unlike refractory met~1, it has a coefficient of ~expansion which matche~ that of the soda-lime glass of the flare sufficiently well to form a seal without an u~due risk of the occurrence of pinch cracks.
~ickel-iron alloy~, for example as sold under the trade- marks NIL0 475, 48 and 51, may be prepared for sealing by pickling in dilute hydrofluoric or hydrochloric acid and nitric acid, followed by rinsing. he metal should then be decarbonized in a wet hydrogen atmosphere at 900-1100 C for about one hour and oxidized immediately before sealing into the glass. he wires may be oxidized by heating to 600-1050C
in a sulphur-rree atmosphere, the time and temperature being chosen to form ah oxide film sufficiently thic~ to have the appearance of a brownish_grey disooloration after sealing.
Trademark _ . . _ . .. __,_ , . _ . .. _ . _ . __ .. .~ .. , , _ .. , . __ , __.. .... . .. . . _ . .. ... .
in operation is composed of wire formed from refractory metAl. The preferred refractory metals for this purpose are high temperature molybdenum, tantalum, titanium, vanadium and niobium.
The remaining portion 14 of the leadwire may be made from a nickel-iron alloy having a coefficient of expansion matched with that of the glass flare 2, which can be of soda-lime glass and may be butt se~1ed into the end of the tube 1.
Fluorescent lamps as shown in Figs. 1 and 2 which embod~ the second important aspect of the invention have a soda-lime glass tube 1 into the end of which a soda-lime glass flare 2 is butt-sealed at the so-called "neck" 16.
~he exhaust tubulation 6 is also formed of soda-lime glass.
It is in the neck region 16 of conventional tube~
that occasional cracks develop owi~g to thermal expacsion mismatch bet~een the lead glass flare and the soda-lime glass tube and these are eliminated by the use of soda-lime glass for the flare. Chemical reduction of the lead glass during sealing often produces a dark seal in the regio~ 3 and makes quality control inspection difficult, and again this is a~oided or reduced by the use of soda-lime glass at this point.
In ~igs. 5, 6, 7 and 8 the leadwires 7 consist ; respectively of one, two, three and four lengths of wire welded where necessary at points indicated generally by the numeral 17.
~he leadwire shown in ~ig. 5 is of nickel-iron alloy having a coefficient of expansion closely matching that of the soda-lime glass of the flare, so as to eliminate or reduce the possibility of pinch cracks forming in the portion 4 of the flare, and the length 18 of the leadwire has a uniform adherent surface coating of oxide, formed during ~abrication of the electrode mount, which partially dissolves -in the glass when the leadwires are sealed into the flare and thereby improves the seal. Sufficient oxide should be present to pre~ent complete solution in the glass, as this may give a weaker seal. The clamp portion 8 may have a re-fractory coating of boron nitride as already described above.
Fig. 6 shows a two-part leadwire, welded at 17a, of - which the portion 19 passing through the flare is made of nickel-iron alloy and has an adherent oxide coating extending over that portion of the leadwire passing through the pinch region of the flare. The portion 20 of the leadwire forming the inner support wire may be made of refractory metal, or of any other suitable metal with or without a boron nitride coating.
~ig. 7 shows a three-part leadwire welded at 1~ and 17c in which the portion 21 sealed into the pinch section of _g_ 8614 ~i ~he flare is made of Dumet, and the portion 22 making up the inner support part of the leadwire is of nickel-iron alloy, with or without a boron nitride coati~g on the clamp.
~i~. 8 shows a four-part leadwire welded at 17d, 17e and 17f, of which ths portion 23 betwee~ the welds 17d and 17e and sealed into the pinch portion of the flare is made from Dumet while the portion 24 between the welds 17e and 17f is made from nickel-iron alloy and connec~ the length of Dumet with the inner support wire 25 of refractory metal or other suitable metal, with or without a boron nitride coating on the clamp. It is necessary to include the ~
~ickel-iron portion 24 because, unlike refractory met~1, it has a coefficient of ~expansion which matche~ that of the soda-lime glass of the flare sufficiently well to form a seal without an u~due risk of the occurrence of pinch cracks.
~ickel-iron alloy~, for example as sold under the trade- marks NIL0 475, 48 and 51, may be prepared for sealing by pickling in dilute hydrofluoric or hydrochloric acid and nitric acid, followed by rinsing. he metal should then be decarbonized in a wet hydrogen atmosphere at 900-1100 C for about one hour and oxidized immediately before sealing into the glass. he wires may be oxidized by heating to 600-1050C
in a sulphur-rree atmosphere, the time and temperature being chosen to form ah oxide film sufficiently thic~ to have the appearance of a brownish_grey disooloration after sealing.
Trademark _ . . _ . .. __,_ , . _ . .. _ . _ . __ .. .~ .. , , _ .. , . __ , __.. .... . .. . . _ . .. ... .
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a fluorescent discharge lamp comprising a light-transmitting envelope, electrodes therein, and support wires connected to said electrodes passing through walls of said envelope and sealed therethrough, the improvement comprising coating at least the surfaces of said wires that are exposed within said envelope to electron bombardment with boron nitride.
2. A lamp according to claim 1 wherein the support wires have a coefficient of thermal expansion matching the glass in which they are sealed.
3. A lamp according to claim 2 wherein the support wires are of nickel-iron alloy and the glass seal is of soda-lime glass.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA349,142A CA1088614A (en) | 1976-07-19 | 1980-04-03 | Fluorescent lamps |
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB30007/76A GB1589472A (en) | 1976-07-19 | 1976-07-19 | Fluorescent lamps |
| GB30007/76 | 1976-07-19 | ||
| GB4200476 | 1976-10-08 | ||
| GB42004/76 | 1976-10-08 | ||
| CA282,964A CA1092636A (en) | 1976-07-19 | 1977-07-18 | Fluorescent lamps |
| CA349,142A CA1088614A (en) | 1976-07-19 | 1980-04-03 | Fluorescent lamps |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1088614A true CA1088614A (en) | 1980-10-28 |
Family
ID=27426001
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA349,142A Expired CA1088614A (en) | 1976-07-19 | 1980-04-03 | Fluorescent lamps |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1088614A (en) |
-
1980
- 1980-04-03 CA CA349,142A patent/CA1088614A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |