CA1143426A - Electric lamp - Google Patents
Electric lampInfo
- Publication number
- CA1143426A CA1143426A CA000364555A CA364555A CA1143426A CA 1143426 A CA1143426 A CA 1143426A CA 000364555 A CA000364555 A CA 000364555A CA 364555 A CA364555 A CA 364555A CA 1143426 A CA1143426 A CA 1143426A
- Authority
- CA
- Canada
- Prior art keywords
- current supply
- lamp
- pinch seal
- coating
- glass
- 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
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
Abstract
ABSTRACT:
electric lamps according to the invention have a quartz glass lamp envelope with a flattened pinch seal in which at least one current supply wire is incorporated.
Over a part of its length the current supply wire has a circumferential coating of intermediate glass, between the ends of which the glass of the pinch seal is fused with that coating. On each of its major side surfaces the flat pinch seal has a raised ridge extending over the whole pinched length of the current supply wires above each of the wires incorporated in the pinch seal.
electric lamps according to the invention have a quartz glass lamp envelope with a flattened pinch seal in which at least one current supply wire is incorporated.
Over a part of its length the current supply wire has a circumferential coating of intermediate glass, between the ends of which the glass of the pinch seal is fused with that coating. On each of its major side surfaces the flat pinch seal has a raised ridge extending over the whole pinched length of the current supply wires above each of the wires incorporated in the pinch seal.
Description
~342~
P~IN g633 l 16, 7~1980 "Electric lamp"
The invention relates to an electric :Lamp having a quartz glass lamp envelope provided with current supply conductors which ex-tend to an electric elernent accommodated inside the lamp envelope, are guided in a vacuum-tight manner through the wall of the lamp envelope and have a circumferential coating of intermediate glass over part of their length, between the ends of which coating the wall of the lamp envelope is fusecl wi-th said coating. Such a lamp is disclosed in British Patent Speci-~ication No. 71OJ434~
Lamps which have a high operating temperatureare often manufactured with a lamp envelope of quart~ glass, which term is used herein to indicate glasses having a SiO2 content of at least 95~ by weight, and 1~i-th current supply conductors of tungsten or molybdenum. These glasses haYe a coefficient of thermal expansion (approx, 7 x 10 7 K ) which differs considerabl-y from that of tungsten (45 x 10 7 K 1) and molybdenum (5~ x 10 7 K ).
Due to these large differences in coefficients of thermal expansion, it is common practice to construct the current supply conductors, at the location where they are incor-porated in the wall of the lamp envelope in a vacuum-tight manner, as a thin foil to which an internal and an external current supply conductor are welded. ~Iowever, during the manufacture of -the welded joint and also upon sealing -the conductors in the wall of the lamp envelope, rejects occur as a result of fracture of the foil. Other disadvantages of this construction are that the welded joints shoulcl always be checked for reliability~ that the ~ assembly of the current supply conductor is slack as a re-sult of the presence of the ~oil so that it is cumbersome to assemble the internal current conductor in the lamp ~1~L3~2~
PHN 9~33 2 16. 7.1980 envelope so as to be well positioned, and that the foil restricts the permissible strength of the lamp current.
Notwithstanding these disadvantages of the construction described, substantially all types o~ lamps with quartz glass lamp envelope which are commercially available have this construction. Only in lamps having a high current strength, for e~ample short-arc discharge l&mps, is a sealed wire necessarily used in practice as a current supply conductor. From this it appears that there are economic and technological restrictions to use sealed wires as current supply conductors in other lamps also.
According to the said British Patent Specifi-cation 710,1~34, a vacuum-tight sealing of the current supply conductor in the wall of the quartz glass lamp envelope is obtained by providing the current supply con-ductor at the area o~ the sealing in the wall of` the lamp envelope with a fused coating of an intermediate glass or a number o~ intermedia-te glasses and to fuse the lamp envelope therewith between the ends of said coating~
~lowever~ it is particularly difficult and time-consuming to realize a good f`usion of` the wall of` the lamp~envelope with the coating of the curren-t supply wire.
In practice, the quartz glass o~ the lamp envelope to be formed is allowed to collapse on to the coating of` the current supply wire. Although this can be accelerated by pressing the quartz glass circumferentially against the glass coating by means of a tool, that process is also difficult to mechan:ize.
On the other ha~d it has been found that if` a 30 pinch seal is manufactured around the glass coa-ting, as is usual in lamps in which a thin metal foil is used to rea-lize a vacuum-tight seal of the lamp envelope, no reliable seal ls obtained and fracture often occurs.
It is the object of -the invention to pro~ide 35 electric lamps having a quartz glass lamp envelope pI'O-vided with current supply wires, which lamps have a robust construction which is sim~le to realize and whlch does not : ' ' ,~
3~2~i PHN 9633 3 16. 7.1980 involve restictions of practical importance as regards ; the diameter of the current supply wires.
In lamps of the kind mentioned in the opening paragraph this object is achieved in tha-t the lamp envelope has at least one flattened pinch seal in which a-t least one current supply wire is accommodated, which pinch~
seal on each of its two major side surfaces has, for each current supply wire accommodated in the pinch seal, a respective raised ridge extending above -the respective wire over its entire pinched length.
It has been found experimentally that this lamp has a reliable cons-truction and is easy to manufacture in a mechanized process, even when current supply wires ¦ of o.6 to 0.8 mm diameter or more are used. In contras-t therewith, lamps in which the larger side surfaces of the pinch seal were not provided with such a raised ridge showed cracks, in many cases even upon cooling right after making the pinch seal.
The invention is based on the following Z0 recognition. Intermediate glasses are generally understood by those skilled in the art to mean glasses having a coefficient of thermal expansion between the coefficients of expansion of the materials to be joined, in this case the metal of the current supply wire and the quartz glass of the lamp envelope. Since due to their high SiO2-content quartz glasses have a very low coefficient of expansion and also a very high sof-tening point~ the intermediate glasses must have a lower SiO2-content to reach a higher coefficient of expansion and at the same -time they have a lower softening temperature.
During the making of a flat pinch seal, the intermediate glass has a temperature which differs only little from the temperature o`f the quartz glass. As a re-sult of this the intermediate glass has a comparatively low viscosity, The pressure exerted by the pinching blocks and transferred to the in-termediate glass by the quartz glass causes the intermediate glass to flow easily, so that , ~` ~
. :
~3~6 PHN 9633 4 16, 7~1980 the coating of the current supply w:ire is damaged, or even disappears partly, upon making a normal pinch seal in which the larger side surfaces are not provided with a raised ridge as have lamps according to -the invention. The current supply wire in the finished pinch seal is no longer embedded in intermediate glass, which causes stresses in the quartz glass which result in cracks.
By providing the facing surfaces of the pinching blocks with respective grooves, the locations of which are matched -to the location~s) of the current supply wire(s) in the still open end of -the lamp envelope -to be formed, the wall of the envelope in the region where it is being pinched together is effectively shaped during the pinching operation -to surround the supply wire(s), As a result, the force applied to the intermediate glass during pinching is very considerably reduced due to the grooves.
As always when deforming glass, it is of im-portance in this case also that the glasses are able to ~use together in such a manner that glass surfaces at the area where they meet do not enclose acute angles. Depon-~; dent on the way in which the sealing process is~carried out i~ may therefore be recommendable to after-heat the pinch seal.
It has been found that the glasses easily fuse together if the quart~ g:Lass of the lamp envelope to be formed is provided wi-th a coating of an intermediate glass at the area where the pinch seal is to be reali~ed. Upon making the pinch seal, said coating needs to fuse only with the coating o~ the current supply wire, which easily occurs as a result of the lower softening temperature of intermediate glass.
The lamps embodying -the invention can be manufactured easily, even in an automated manner~ They have a very reliable construction and enable high curren-t strengths with lo~ resistance losses. ~urther, the con-struction enables several current supply wires -to be .
PHN ~633 5 16. 7.1980 sealed in one pinch seal. Of course this is impossible in the construction of the lamp disclosed in the above-mentioned British Patent Specification, since in that construction the sealing of the current supply wire is rotationally s~nme-trical.
The lamp according to the invention may be a discharge lamp, for example, a high-pressure ~nercury vapour discharge lamp, in which case the said element accommodated inside the lamp envelope is a pair of main electrodes. A current supply wire to an auxiliary electrode may be incorporated in a pinch seal in addi-tion to the current supply wire to a main electrode. Alternatively, -the lamp in accordance with the invention may have a filament as the electric element, in which case the lamp may be constructed as a -two-pinch or as a mono-pinch lamp, de-pendent on its destined use.
It has beeen found that very good results are obtained with intermediate glasses which over a temperature range of 30-800oC have a coefficient of -thermal expansion (~) in -the range of approx. 11 to 17 x 10 7 K 1.
Examples o:f such glasses are recorded in the ~ollowing table (composition in per cent by weight):
;
21 B203 A1203l CaO ¦~x 107 (K 1) I a 86.9¦ g.ol 4~
~b 86.41 9.6j 4.0 1 ~ 13 c 81.9l 13.1 4.5 ~ o.5 ¦ 15 d 81.0¦ 10.9 ! 7.1 j 1.0 ~ 17 . . . ~ . . _ _ .
The in-termediate glasses can be sealed -to the current supply wires of tungsten or molybdenum in a con-ven-tional manner so as to ~orm a coating thereon. For example, i:f glass in the form of a rod is used, the glass may be applied to the wire in a flameO If -the glass is available in tube form, -then it may be slid on the wire and sealed to the wire, for example by inductive heating - : ~
' ~3~26 P~ 9633 6 17.7.80 causing the tube to collapse on to the wire.
In lamps in which a vacuum-tight seal is realized around a foil incorporated in a pinch seal, the pinch seal is vacuum-tight only over a part of th0 length of the foil which lies be-tween the ends of the internal and external current conductors welded to the foil. In order to lock this internal and external current con-ductors mechanically in the pinch seal, the length of the said pinch seal much be significantly larger than the length of the vacuum-tight part. In lamps in accordance with the invention, however, the pinch seal is vacuum-tight over the whole pinched length of the current supply wire. This enables lamps according to the invention to be provided with considerably shorter pinch seals, which not only involves a saving of quartz glass but also results in a smaller lamp. As a result of this luminaires of smaller dimensions and lower weight are made possible.
United States Patent Specification 3,742,2~3 discloses an electric lamp having a quartz g-ass lamp en-velope provided with a pinch seal, in which the current supply wires are enveloped by cermet over the part which is situated in the pinch seal. On its major surfaces the known lamp has a raised ridge extending above the current supply1wires.
Although this lamp shows some resemblance with the lamp according to the invention, there are diPferen-ces which are of essential importance. The above United States Patent Speci~ication states that only one cermet will suffice when the current supply wires have a diame-3n ter of approximately 300/um. When the thickness of the current supply wires is 750/um or more, two or more con-centric envelopes of different coefficients of thermal expansion have to be used.
However, lamps having current supply wires of 300/um thickness are exceptional, so that the vast majo-ri-ty of the lamps according to the United States Patent Specif`ica~ion, must have two or more concentric envelopes ~ of cermet on the current supply wires. In addition, cer-::
~ 3 ~Z 6 P~ 9633 7 17.7 ~o mets are difficult to process.
In the lamps according to the invention on the contrary, one enveloping layer of glass, which can easily : be provided, will always suffice.
The cermets which are used according to the said ~nited States Patent Specification are more viscous than quartz glass, also at high temperatures, because they comprise a hi~h melting-point metal, for example tungsten. The intermediate glass used in lamps according to the in~ention is less viscous -than. quartz glass, since it has a lower SiO2 content.
; In lamps according to the United States Patent ~: Specification a raised ridge is provided on the major surfaces of the pinch seal above the current supply wires so as to prevent that, upon making the pinch seal, the comparatively little viscous quartz glass is pressed in the longitudinal direction o~ the current supply wires away from the very viscous cermet envelopes and lands be-side the cermets on the bare parts of the current supply wires. However, this could also be prevented in that the : ` envelopes of cermets have such a length that the quart~
:~: glass cannot reach the bare parts of the current supply wires.
In the lamps according -to the invention on the contrary a raised ridge is provided 90 as to prevent the quartz glass from pressing away the much less viscous in-termediate glass and ~rom contacting, instead o~ the in-termediate glass, a part o~ the current supply wire in question which has become bare. Therefore, in the lamp according to the invention a coating of intermediate glass of larger length is no alternative for the use of a : raised ridge.
The lamp according to the invention thus has a construc-tion which is simpler and more universal and can be made more easily. The raised ridge above the current supply wires have a different effect.
Embodiments of lamps according to the invention will now be described wlth reference to the accompanying ~; .
~ 1 ~ 3 ~ ~
PHN 9633 8 17,7,80 drawing. In the drawing Figure 1 is a longitudinal sectional view through a high-pressure mercury vapour discharge lamp, Figure 2 is a sectional vîew through the lamp shown in Figure 1 taken on the line II-II, Figure 3 is a side elevation of a mono-pinch halogen incandescent lamp, Figure 4 is a cross-sectional view t,hrough the pinch seal o~ the lamp shown in Figure 3 taken on the line IV IV, Figure 5 is a side elevation of a two-pinch halogen incandescent lamp, and Figure 6 is a sectional view through the lamp shown in Figure 5 -taken on the line VI-~I.
I~ Figure 1, a quartz glass lamp envelope 1 has flat pinch seals 2 and 3. A current supply wire 4 is passed through pinch seal 2, around which wire 4 the pinch seal 2 has the same geometry as pinch seal 3 around a current supply wire 5~ Over a part of its length cur-rent supply wire 5 has a circum~erential coating of in-termediate glass 6 of the composition b in the above table, which i5 fused to the wire 5. Between the ends o~
the coating 6 the quartz glass of the pinch seal 3 is fused therewith. The current supply wire 5, which con-sists of tungsten and as a diameter of 800/um, has tung-sten wire turns 8 at its end 7 so as to form a main elec-trode. Adjacent the wire 5 in pinch 3, is a tungsten wire 10 provided with a coating 9 of the same intermediate glass. The end 11 of wire 10 forms an auxiliary elec-trode.
In Figure 2 the shape of the flat pinch seal 3is clearly visible. The pinch seal 3 has smaller side sur~aces 12 and 13 and larger side surfaces 14 and 15.
On the latter are present raised ridges 16 ancl 17, res-pectively, each situated above the current supply wire 5and its coating 6 and extending over-its entire pinched length. Raised ridges 1~ and 19, respectively, are also present above the current supply wire 10 and its coating 1~3~2~
PI~ 9633 9 17.7 80 9.
In Figure 3, molybdenum current supply wires 32 and 33, respecti~ely, of 600/um diameter are incor porated in a vacuum-tight manner in the flat pinch seal 30 of a quartz glass lamp envelope 31. The wires have coatings 34 and 35, respectively, of intermediate glass of the composition d from the table. The current supply wires 32 and 33 support a tungsten filament 46.
It is visible in Figure 4 that raised rilges 38, 39, 40 and 41, respectively~ are present above each of the current supply wires 32 and 33, respectively, in-corporated in the ~lat pinch seal on the major side sur-~aces 36 and 37 of the pinch seal. They extend over the whole pinched length of the current supply wires 32 and lS 33. The lamp shown may be used for projection purposes.
In Figure 5 the quartz glass lamp envelope 50 has flat pinch seals 51 and 52 of the same geometry. A
tungsten current supply wire 53 of 700/um diameter is in-corporated in pinch seal 52, on which wire a coating 54 of composition a from the table is sealed. Between the ends of coating 54 -the glass of the pinch seal 52 is fus-ed therewith. At its end situated inside the lamp ~essel 50 the current supply wire has a few tungsten wire turns 55 which are screwed in the filament 56c The lamp may be used as a floodlight lamp.
Fig~lre 6 shows raised ridges 59 and 60 present above -the current sL1pply wire 53 and its coating 54 on the respective larger side surfaces 57 and 58 of the pinch seal 52, which ridges extend o~er the whole length o~ the current supply wire 53.
P~IN g633 l 16, 7~1980 "Electric lamp"
The invention relates to an electric :Lamp having a quartz glass lamp envelope provided with current supply conductors which ex-tend to an electric elernent accommodated inside the lamp envelope, are guided in a vacuum-tight manner through the wall of the lamp envelope and have a circumferential coating of intermediate glass over part of their length, between the ends of which coating the wall of the lamp envelope is fusecl wi-th said coating. Such a lamp is disclosed in British Patent Speci-~ication No. 71OJ434~
Lamps which have a high operating temperatureare often manufactured with a lamp envelope of quart~ glass, which term is used herein to indicate glasses having a SiO2 content of at least 95~ by weight, and 1~i-th current supply conductors of tungsten or molybdenum. These glasses haYe a coefficient of thermal expansion (approx, 7 x 10 7 K ) which differs considerabl-y from that of tungsten (45 x 10 7 K 1) and molybdenum (5~ x 10 7 K ).
Due to these large differences in coefficients of thermal expansion, it is common practice to construct the current supply conductors, at the location where they are incor-porated in the wall of the lamp envelope in a vacuum-tight manner, as a thin foil to which an internal and an external current supply conductor are welded. ~Iowever, during the manufacture of -the welded joint and also upon sealing -the conductors in the wall of the lamp envelope, rejects occur as a result of fracture of the foil. Other disadvantages of this construction are that the welded joints shoulcl always be checked for reliability~ that the ~ assembly of the current supply conductor is slack as a re-sult of the presence of the ~oil so that it is cumbersome to assemble the internal current conductor in the lamp ~1~L3~2~
PHN 9~33 2 16. 7.1980 envelope so as to be well positioned, and that the foil restricts the permissible strength of the lamp current.
Notwithstanding these disadvantages of the construction described, substantially all types o~ lamps with quartz glass lamp envelope which are commercially available have this construction. Only in lamps having a high current strength, for e~ample short-arc discharge l&mps, is a sealed wire necessarily used in practice as a current supply conductor. From this it appears that there are economic and technological restrictions to use sealed wires as current supply conductors in other lamps also.
According to the said British Patent Specifi-cation 710,1~34, a vacuum-tight sealing of the current supply conductor in the wall of the quartz glass lamp envelope is obtained by providing the current supply con-ductor at the area o~ the sealing in the wall of` the lamp envelope with a fused coating of an intermediate glass or a number o~ intermedia-te glasses and to fuse the lamp envelope therewith between the ends of said coating~
~lowever~ it is particularly difficult and time-consuming to realize a good f`usion of` the wall of` the lamp~envelope with the coating of the curren-t supply wire.
In practice, the quartz glass o~ the lamp envelope to be formed is allowed to collapse on to the coating of` the current supply wire. Although this can be accelerated by pressing the quartz glass circumferentially against the glass coating by means of a tool, that process is also difficult to mechan:ize.
On the other ha~d it has been found that if` a 30 pinch seal is manufactured around the glass coa-ting, as is usual in lamps in which a thin metal foil is used to rea-lize a vacuum-tight seal of the lamp envelope, no reliable seal ls obtained and fracture often occurs.
It is the object of -the invention to pro~ide 35 electric lamps having a quartz glass lamp envelope pI'O-vided with current supply wires, which lamps have a robust construction which is sim~le to realize and whlch does not : ' ' ,~
3~2~i PHN 9633 3 16. 7.1980 involve restictions of practical importance as regards ; the diameter of the current supply wires.
In lamps of the kind mentioned in the opening paragraph this object is achieved in tha-t the lamp envelope has at least one flattened pinch seal in which a-t least one current supply wire is accommodated, which pinch~
seal on each of its two major side surfaces has, for each current supply wire accommodated in the pinch seal, a respective raised ridge extending above -the respective wire over its entire pinched length.
It has been found experimentally that this lamp has a reliable cons-truction and is easy to manufacture in a mechanized process, even when current supply wires ¦ of o.6 to 0.8 mm diameter or more are used. In contras-t therewith, lamps in which the larger side surfaces of the pinch seal were not provided with such a raised ridge showed cracks, in many cases even upon cooling right after making the pinch seal.
The invention is based on the following Z0 recognition. Intermediate glasses are generally understood by those skilled in the art to mean glasses having a coefficient of thermal expansion between the coefficients of expansion of the materials to be joined, in this case the metal of the current supply wire and the quartz glass of the lamp envelope. Since due to their high SiO2-content quartz glasses have a very low coefficient of expansion and also a very high sof-tening point~ the intermediate glasses must have a lower SiO2-content to reach a higher coefficient of expansion and at the same -time they have a lower softening temperature.
During the making of a flat pinch seal, the intermediate glass has a temperature which differs only little from the temperature o`f the quartz glass. As a re-sult of this the intermediate glass has a comparatively low viscosity, The pressure exerted by the pinching blocks and transferred to the in-termediate glass by the quartz glass causes the intermediate glass to flow easily, so that , ~` ~
. :
~3~6 PHN 9633 4 16, 7~1980 the coating of the current supply w:ire is damaged, or even disappears partly, upon making a normal pinch seal in which the larger side surfaces are not provided with a raised ridge as have lamps according to -the invention. The current supply wire in the finished pinch seal is no longer embedded in intermediate glass, which causes stresses in the quartz glass which result in cracks.
By providing the facing surfaces of the pinching blocks with respective grooves, the locations of which are matched -to the location~s) of the current supply wire(s) in the still open end of -the lamp envelope -to be formed, the wall of the envelope in the region where it is being pinched together is effectively shaped during the pinching operation -to surround the supply wire(s), As a result, the force applied to the intermediate glass during pinching is very considerably reduced due to the grooves.
As always when deforming glass, it is of im-portance in this case also that the glasses are able to ~use together in such a manner that glass surfaces at the area where they meet do not enclose acute angles. Depon-~; dent on the way in which the sealing process is~carried out i~ may therefore be recommendable to after-heat the pinch seal.
It has been found that the glasses easily fuse together if the quart~ g:Lass of the lamp envelope to be formed is provided wi-th a coating of an intermediate glass at the area where the pinch seal is to be reali~ed. Upon making the pinch seal, said coating needs to fuse only with the coating o~ the current supply wire, which easily occurs as a result of the lower softening temperature of intermediate glass.
The lamps embodying -the invention can be manufactured easily, even in an automated manner~ They have a very reliable construction and enable high curren-t strengths with lo~ resistance losses. ~urther, the con-struction enables several current supply wires -to be .
PHN ~633 5 16. 7.1980 sealed in one pinch seal. Of course this is impossible in the construction of the lamp disclosed in the above-mentioned British Patent Specification, since in that construction the sealing of the current supply wire is rotationally s~nme-trical.
The lamp according to the invention may be a discharge lamp, for example, a high-pressure ~nercury vapour discharge lamp, in which case the said element accommodated inside the lamp envelope is a pair of main electrodes. A current supply wire to an auxiliary electrode may be incorporated in a pinch seal in addi-tion to the current supply wire to a main electrode. Alternatively, -the lamp in accordance with the invention may have a filament as the electric element, in which case the lamp may be constructed as a -two-pinch or as a mono-pinch lamp, de-pendent on its destined use.
It has beeen found that very good results are obtained with intermediate glasses which over a temperature range of 30-800oC have a coefficient of -thermal expansion (~) in -the range of approx. 11 to 17 x 10 7 K 1.
Examples o:f such glasses are recorded in the ~ollowing table (composition in per cent by weight):
;
21 B203 A1203l CaO ¦~x 107 (K 1) I a 86.9¦ g.ol 4~
~b 86.41 9.6j 4.0 1 ~ 13 c 81.9l 13.1 4.5 ~ o.5 ¦ 15 d 81.0¦ 10.9 ! 7.1 j 1.0 ~ 17 . . . ~ . . _ _ .
The in-termediate glasses can be sealed -to the current supply wires of tungsten or molybdenum in a con-ven-tional manner so as to ~orm a coating thereon. For example, i:f glass in the form of a rod is used, the glass may be applied to the wire in a flameO If -the glass is available in tube form, -then it may be slid on the wire and sealed to the wire, for example by inductive heating - : ~
' ~3~26 P~ 9633 6 17.7.80 causing the tube to collapse on to the wire.
In lamps in which a vacuum-tight seal is realized around a foil incorporated in a pinch seal, the pinch seal is vacuum-tight only over a part of th0 length of the foil which lies be-tween the ends of the internal and external current conductors welded to the foil. In order to lock this internal and external current con-ductors mechanically in the pinch seal, the length of the said pinch seal much be significantly larger than the length of the vacuum-tight part. In lamps in accordance with the invention, however, the pinch seal is vacuum-tight over the whole pinched length of the current supply wire. This enables lamps according to the invention to be provided with considerably shorter pinch seals, which not only involves a saving of quartz glass but also results in a smaller lamp. As a result of this luminaires of smaller dimensions and lower weight are made possible.
United States Patent Specification 3,742,2~3 discloses an electric lamp having a quartz g-ass lamp en-velope provided with a pinch seal, in which the current supply wires are enveloped by cermet over the part which is situated in the pinch seal. On its major surfaces the known lamp has a raised ridge extending above the current supply1wires.
Although this lamp shows some resemblance with the lamp according to the invention, there are diPferen-ces which are of essential importance. The above United States Patent Speci~ication states that only one cermet will suffice when the current supply wires have a diame-3n ter of approximately 300/um. When the thickness of the current supply wires is 750/um or more, two or more con-centric envelopes of different coefficients of thermal expansion have to be used.
However, lamps having current supply wires of 300/um thickness are exceptional, so that the vast majo-ri-ty of the lamps according to the United States Patent Specif`ica~ion, must have two or more concentric envelopes ~ of cermet on the current supply wires. In addition, cer-::
~ 3 ~Z 6 P~ 9633 7 17.7 ~o mets are difficult to process.
In the lamps according to the invention on the contrary, one enveloping layer of glass, which can easily : be provided, will always suffice.
The cermets which are used according to the said ~nited States Patent Specification are more viscous than quartz glass, also at high temperatures, because they comprise a hi~h melting-point metal, for example tungsten. The intermediate glass used in lamps according to the in~ention is less viscous -than. quartz glass, since it has a lower SiO2 content.
; In lamps according to the United States Patent ~: Specification a raised ridge is provided on the major surfaces of the pinch seal above the current supply wires so as to prevent that, upon making the pinch seal, the comparatively little viscous quartz glass is pressed in the longitudinal direction o~ the current supply wires away from the very viscous cermet envelopes and lands be-side the cermets on the bare parts of the current supply wires. However, this could also be prevented in that the : ` envelopes of cermets have such a length that the quart~
:~: glass cannot reach the bare parts of the current supply wires.
In the lamps according -to the invention on the contrary a raised ridge is provided 90 as to prevent the quartz glass from pressing away the much less viscous in-termediate glass and ~rom contacting, instead o~ the in-termediate glass, a part o~ the current supply wire in question which has become bare. Therefore, in the lamp according to the invention a coating of intermediate glass of larger length is no alternative for the use of a : raised ridge.
The lamp according to the invention thus has a construc-tion which is simpler and more universal and can be made more easily. The raised ridge above the current supply wires have a different effect.
Embodiments of lamps according to the invention will now be described wlth reference to the accompanying ~; .
~ 1 ~ 3 ~ ~
PHN 9633 8 17,7,80 drawing. In the drawing Figure 1 is a longitudinal sectional view through a high-pressure mercury vapour discharge lamp, Figure 2 is a sectional vîew through the lamp shown in Figure 1 taken on the line II-II, Figure 3 is a side elevation of a mono-pinch halogen incandescent lamp, Figure 4 is a cross-sectional view t,hrough the pinch seal o~ the lamp shown in Figure 3 taken on the line IV IV, Figure 5 is a side elevation of a two-pinch halogen incandescent lamp, and Figure 6 is a sectional view through the lamp shown in Figure 5 -taken on the line VI-~I.
I~ Figure 1, a quartz glass lamp envelope 1 has flat pinch seals 2 and 3. A current supply wire 4 is passed through pinch seal 2, around which wire 4 the pinch seal 2 has the same geometry as pinch seal 3 around a current supply wire 5~ Over a part of its length cur-rent supply wire 5 has a circum~erential coating of in-termediate glass 6 of the composition b in the above table, which i5 fused to the wire 5. Between the ends o~
the coating 6 the quartz glass of the pinch seal 3 is fused therewith. The current supply wire 5, which con-sists of tungsten and as a diameter of 800/um, has tung-sten wire turns 8 at its end 7 so as to form a main elec-trode. Adjacent the wire 5 in pinch 3, is a tungsten wire 10 provided with a coating 9 of the same intermediate glass. The end 11 of wire 10 forms an auxiliary elec-trode.
In Figure 2 the shape of the flat pinch seal 3is clearly visible. The pinch seal 3 has smaller side sur~aces 12 and 13 and larger side surfaces 14 and 15.
On the latter are present raised ridges 16 ancl 17, res-pectively, each situated above the current supply wire 5and its coating 6 and extending over-its entire pinched length. Raised ridges 1~ and 19, respectively, are also present above the current supply wire 10 and its coating 1~3~2~
PI~ 9633 9 17.7 80 9.
In Figure 3, molybdenum current supply wires 32 and 33, respecti~ely, of 600/um diameter are incor porated in a vacuum-tight manner in the flat pinch seal 30 of a quartz glass lamp envelope 31. The wires have coatings 34 and 35, respectively, of intermediate glass of the composition d from the table. The current supply wires 32 and 33 support a tungsten filament 46.
It is visible in Figure 4 that raised rilges 38, 39, 40 and 41, respectively~ are present above each of the current supply wires 32 and 33, respectively, in-corporated in the ~lat pinch seal on the major side sur-~aces 36 and 37 of the pinch seal. They extend over the whole pinched length of the current supply wires 32 and lS 33. The lamp shown may be used for projection purposes.
In Figure 5 the quartz glass lamp envelope 50 has flat pinch seals 51 and 52 of the same geometry. A
tungsten current supply wire 53 of 700/um diameter is in-corporated in pinch seal 52, on which wire a coating 54 of composition a from the table is sealed. Between the ends of coating 54 -the glass of the pinch seal 52 is fus-ed therewith. At its end situated inside the lamp ~essel 50 the current supply wire has a few tungsten wire turns 55 which are screwed in the filament 56c The lamp may be used as a floodlight lamp.
Fig~lre 6 shows raised ridges 59 and 60 present above -the current sL1pply wire 53 and its coating 54 on the respective larger side surfaces 57 and 58 of the pinch seal 52, which ridges extend o~er the whole length o~ the current supply wire 53.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electric lamp having a quartz glass lamp envelope provided with current supply conductors which extend to an electric element accommodated inside the lamp envelope, are guided in a vacuum-tight manner through the wall of the lamp envelope and have a circum-ferential coating of intermediate glass over part of their length, between the ends of which coating the wall of the lamp envelope is fused with said coating, characterized in that the lamp envelope has at least one flattened pinch seal in which at least one current supply wire is accommodated, which pinch seal on each of its two major side surfaces has, for each current supply wire accom-modated in the pinch seal, a raised ridge extending above the respective wire over its entire pinched length.
2. An electric lamp as claimed in Claim 1, char-acterized in that at least two current supply wires are incorporated in a said pinch seal.
3. An electric lamp as claimed in Claim 1 or 2, characterized in that in the temperature range of 30-800° C the intermediate glass has a coefficient of thermal expansion in the range from 11 to 17 x 10-7 K-1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7908413 | 1979-11-19 | ||
| NL7908413A NL7908413A (en) | 1979-11-19 | 1979-11-19 | ELECTRIC LAMP. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1143426A true CA1143426A (en) | 1983-03-22 |
Family
ID=19834202
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000364555A Expired CA1143426A (en) | 1979-11-19 | 1980-11-13 | Electric lamp |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5686434A (en) |
| BE (1) | BE886211A (en) |
| BR (1) | BR8007478A (en) |
| CA (1) | CA1143426A (en) |
| DE (1) | DE3043193A1 (en) |
| ES (1) | ES8204881A1 (en) |
| FR (1) | FR2470441A1 (en) |
| GB (1) | GB2064216B (en) |
| HU (1) | HU182237B (en) |
| IT (1) | IT1193996B (en) |
| NL (1) | NL7908413A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8302128A (en) * | 1983-06-15 | 1985-01-02 | Philips Nv | LOW PRESSURE SODIUM VAPOR DISCHARGE LAMP. |
| US4631446A (en) * | 1984-05-04 | 1986-12-23 | Gte Products Corporation | Single-ended high intensity discharge lamp |
| DE3615944A1 (en) * | 1986-05-12 | 1987-11-19 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | ELECTRIC LAMP |
| JPH0719562B2 (en) * | 1988-02-23 | 1995-03-06 | エヌ・ベー・フィリップス・フルーイランペンファブリケン | Light |
| DE69822058D1 (en) * | 1997-09-19 | 2004-04-08 | Matsushita Electric Ind Co Ltd | High-pressure discharge lamp and method for producing the same |
| KR20030046319A (en) * | 2001-12-05 | 2003-06-12 | 마쯔시다덴기산교 가부시키가이샤 | High pressure discharge lamp and lamp unit |
| US20050211370A1 (en) * | 2005-06-20 | 2005-09-29 | Osram Sylvania Inc. | Ceramic discharge vessel with joined capillaries |
| DE102006060804A1 (en) * | 2006-12-21 | 2008-06-26 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Low-voltage halogen lamp |
| CN107324657A (en) * | 2017-07-01 | 2017-11-07 | 北京曙光明电子光源仪器有限公司 | A kind of preparation method of transitional glass joint |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3742283A (en) * | 1971-10-28 | 1973-06-26 | Gte Sylvania Inc | Press seal for lamp having fused silica envelope |
| NL7513429A (en) * | 1975-11-18 | 1977-05-23 | Philips Nv | HALOGEN BULB. |
-
1979
- 1979-11-19 NL NL7908413A patent/NL7908413A/en not_active Application Discontinuation
-
1980
- 1980-11-13 CA CA000364555A patent/CA1143426A/en not_active Expired
- 1980-11-14 IT IT25997/80A patent/IT1193996B/en active
- 1980-11-14 GB GB8036565A patent/GB2064216B/en not_active Expired
- 1980-11-14 HU HU802733A patent/HU182237B/en unknown
- 1980-11-14 FR FR8024273A patent/FR2470441A1/en active Granted
- 1980-11-15 DE DE19803043193 patent/DE3043193A1/en not_active Withdrawn
- 1980-11-17 BE BE0/202835A patent/BE886211A/en not_active IP Right Cessation
- 1980-11-17 BR BR8007478A patent/BR8007478A/en unknown
- 1980-11-17 ES ES496909A patent/ES8204881A1/en not_active Expired
- 1980-11-19 JP JP16211380A patent/JPS5686434A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| FR2470441B1 (en) | 1983-04-08 |
| BE886211A (en) | 1981-05-18 |
| DE3043193A1 (en) | 1981-08-27 |
| JPS5686434A (en) | 1981-07-14 |
| ES496909A0 (en) | 1982-05-01 |
| FR2470441A1 (en) | 1981-05-29 |
| GB2064216B (en) | 1983-02-02 |
| ES8204881A1 (en) | 1982-05-01 |
| IT1193996B (en) | 1988-08-31 |
| IT8025997A0 (en) | 1980-11-14 |
| BR8007478A (en) | 1981-06-02 |
| GB2064216A (en) | 1981-06-10 |
| NL7908413A (en) | 1981-06-16 |
| HU182237B (en) | 1983-12-28 |
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| MKEX | Expiry |