CA2243255A1 - Incandescent lamp having tungsten-halogen capsule with titania/silica external infrared reflective coating and oxygen-filled outer jacket - Google Patents
Incandescent lamp having tungsten-halogen capsule with titania/silica external infrared reflective coating and oxygen-filled outer jacket Download PDFInfo
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- CA2243255A1 CA2243255A1 CA 2243255 CA2243255A CA2243255A1 CA 2243255 A1 CA2243255 A1 CA 2243255A1 CA 2243255 CA2243255 CA 2243255 CA 2243255 A CA2243255 A CA 2243255A CA 2243255 A1 CA2243255 A1 CA 2243255A1
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Abstract
An incandescent lamp comprises a hermetically sealed envelope with a first fill gas including halogen contained by the envelope, at least one tungsten filament sealed in the envelope and supported by lead-in wires, and a titania/silica infrared reflective coating on an outside surface of the envelope. An outer jacket encloses the envelope, the outer jacket having therein a second fill gas at a pressure of no more than about 600 torr, the fill gas consisting of a mixture of helium and oxygen.
Description
97-l-070 -l- PATENT APPLICATION
INCANDESCENT LAMP HAVING TUNGSTEN-HALOGEN
CAPSULE WITH TITANIA/SILICA EXTERNAL INFRARED REFLECTIVE
COATING AND OXYGEN-FILLED OUTER JACKET
BACKGROUND OF THE INVENTION
l. Field of the Invention The invention relates to electric incandescent lamps and is directed more particularly to a tungsten-halogen lamp.
INCANDESCENT LAMP HAVING TUNGSTEN-HALOGEN
CAPSULE WITH TITANIA/SILICA EXTERNAL INFRARED REFLECTIVE
COATING AND OXYGEN-FILLED OUTER JACKET
BACKGROUND OF THE INVENTION
l. Field of the Invention The invention relates to electric incandescent lamps and is directed more particularly to a tungsten-halogen lamp.
2. Description of the Prior Art Tungsten-halogen lamps are well known in the art and may include a hardglass envelope having a pair of lead-in wires. A tungsten filament extends between the internal termination of the lead-in wires. The envelope is hermetically sealed, typically by a press seal. The envelope is filled with an inert gas, and one or more halogens (i.e., iodine, bromine, chlorine and fluorine).
The hardglass is a material having a linear coefficient of thermal expansion of from about 30 to 50 X 10-7 in/in/~C, having softening temperatures from about 750~C to about 1020~C, and having a strain point of about 650~C to about 760~C. Exemplary of such materials are the borosLlicate and aluminosilicate glasses. A suitable glass is discussed in U.S. Patents Nos. 4,060,423 and 4,105,826.
As the lamp wattage is increased and/or the size of the lamp envelope is decreased, the envelope wall temperature CA 022432~ 1998-07-16 increases, causing some of the alkaline ions of the hardglass (i.e., barium, strontium and calcium ions) to diffuse to the inner surface of the glass and/or outgas into the lamp where they interact with the halogen gas. The result is a condensation of the reacted halogen gas on inner walls of the lamp, which reduces the available halogen level in the lamp. Sufficient depletion of the halogen content in this manner can lead to failure of the halogen cycle, and blackening of the envelope wall, due to deposited tungsten.
In view of the limitations of using hardglass for the envelope of a tungsten halogen incandescent lamp, the envelope of such lamps sometimes i8 made from vitreous fused silica (i.e., quartz) or a high silica content glass, such as one composed of ninety-six per cent silica. However, quartz and ninety-six per cent silica glass are difficult to process and therefore relatively expensive. Also, lamps made of quartz require a moly foil seal which is also somewhat more difficult and expensive to fabricate.
To prevent the reaction of halogen with the lamp envelope and to alleviate the need to use quartz or 96~
silica glass, it is known to provide a tungsten-halogen incandescent lamp with an internal barrier layer of silicon dioxide (SiO2). The coating forms a continuous and glassy barrier on the inner surface of the lamp envelope which prevents alkaline ions of the hardglass of the envelope from reaching the atmosphere in the envelope. The halogen is thus prevented from reacting with the alkaline ions of the CA 022432~ 1998-07-16 hardglass, leaving the halogen in a gaseous stat:e. In U.S.
Patent No. 5,473,226 issued December 5, 1995 to Mark D.
Beschle et al, the silicon dioxide coating is discussed in detail.
It is also known to provide a tungsten-halogen incandescent lamp envelope with an external coating of infrared ray reflection material to make use of the usually wasted infrared energy emitted by incandescent lamps. The infrared ray reflection film transmits visible rays and reflects infrared rays back to the filament, thereby decreasing the energy needed to maintain the filament at its operating temperature.
In U.S. Patent No. 4,160, 929, issued July l0, 1979 to Luke Thorington et al, there is disclosed an external coating comprising three layers, including a first layer of titanium dioxide (TiO2), a second layer of silver (Ag), and a third layer of titanium dioxide.
In U.S. Patent No. 4,524,410, isgued June 18, 1985 to Akira Kawakatsu et al, there is discussed an envelope external coating comprising three layers, including a first layer of titanium dioxide (TiO2), a second layer of silica (SiO2) and a third layer of titanium dioxide. There is also discussed the use of materials other than titanium dioxide, such as zirconium dioxide (ZrO2), tantalum pentoxide (Ta2Os) and cerium dioxide (CeO2), and the use of materials other than silica, such as magnesia (MgO) and alumina (Al203). A
CA 022432~ l998-07-l6 single layered film of titanium dioxide is further suggested.
In U.S. Patent No. 5,422,534, issued June 6, 1995 to Frederick W. Dynys, there is disclosed a reflective coating for incandescent lamps, the coating including alternating layers of titania, tantala and silica.
It is known also to use a coating of alternating layers of titania and silica.
Unfortunately, when a reflective coating is used on a capsule in a parabolic reflector lamp, the capsule wall temperature can exceed the use temperature range for most hard glass formulations. When the capsule wall sustains high temperatures for long periods of time, the halogen in the capsule reacts with the capsule wall, leading to a reduction in the available halogen content, thus causing the halogen cycle to fail. Accordingly, quartz envelopes are frequently used in combination with the infrared reflective coatings in parabolic reflector lamps, making the infrared conserving products very expensive and less cost effective than they might otherwise be. To reduce the cost of the lamp substantially, it appears necessary that the capsule envelope be of hardglass rather than quartz.
It had been thought that the above-mentioned inside coating of silicon dioxide, or the like, would solve the problem by eliminating the halogen reaction with the hardglass capsule wall. While the interior barrier layer appears to have merit, it is clear that a further safeguard CA 022432~ 1998-07-16 is needed, either in place of, or in addition to, the interior barrier. It appears that the solution to the cost and halogen cycle failure problems in a tungsten-halogen capsule for a parabolic reflector lamp, wherein the capsule i9 provided with a infrared reflective outer coating, is to provide a hardglass capsule and means to cool the capsule to an operational temperature consistent with the operational temperature of a hardglass capsule without the infrared reflective coating. It has been found that filling the outer jacket with helium provides the necessary cooling effect; however, the helium fill may have the deleterious effect of reducing the titania layer on the capsule exterior. This reduction can result in a 1088 of visible transmission of the coating.
S Accordingly, there is a need to provide an incandescent lamp, and in particular, a parabolic reflector lamp, wherein a hardglass tungsten-halogen capsule is provided with an outer coating of titania-silica and wherein the visible light transmission is not degraded by reduction of the titania.
There is further a need to provide a lamp as described immediately above, wherein the outer coating may be used in conjunction with the aforesaid silicon dioxide inner coating.
CA 022432~ 1998-07-16 SUMMARY OF THE INVENTION
An object of the invention is, therefore, to provide an incandescent lamp wherein a tungsten-halogen capsule is provided with an outside coating of titania-silica and wherein visible light transmission is not degraded by reduction of the titania in the outside coating.
A further object of the invention is to provide an incandescent lamp wherein a hardglass tungsten-halogen capsule is provided with an outside coating of titania-silica.
A further object of the invention is to provide aparabolic reflector lamp including a tungsten-halogen capsule disposed in an outer jacket comprising a parabolic reflector hermetically sealed around the capsule.
A still further object of the invention is to provide an incandescent lamp wherein a tungsten-halogen capsule is provided with an outside coating of titania-silica and an inside coating of silicon dioxide.
With the above and other objects in view, as will hereinafter appear, there is provided an incandescent lamp comprising a hermetically sealed envelope, a first fill gas including halogen contained by the envelope, at least one tungsten filament sealed in the envelope and supported by lead-in wires, and a titania/silica infrared reflective coating on an outside surface of the envelope. An outer jacket encloses the envelope, the outer jacket having therein a second fill gas at a pressure of no more than CA 022432~ 1998-07-16 97-l-070 -7- PATENT APPLICATION
about 600 torr, the fill gas consisting of a mixture of helium and oxygen.
In accordance with a further feature of the invention, the capsule is of hardglass.
In accordance with a further feature of the invention the aforementioned outer jacket comprises a parabolic reflector hermetically sealed about the envelope.
In accordance with a still further feature of the invention, there is provided on an inside surface of the envelope a coating of silicon dioxide.
The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention.
The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is made to the accompanying drawings in which is shown an illustrative embodiment of the invention, from which its novel features and advantages will be apparent.
In the drawings:
CA 022432~ 1998-07-16 FIG. 1 is a sectional view of one form of incandescent capsule illustrative of an embodiment of the invention; and FIG. 2 is a partly elevational and partly sectional view showing the capsule of FIG. 1 in combination with an outer jacket comprising a parabolic reflector.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, it will be seen that an illustrative embodiment of the invention includes tungsten-halogen capsule 10 comprising a hermetically sealed envelope 12, preferably of hardglass, but alternatively of quartz, or 96~ silica glass, enclosing at least one tungsten filament 14 supported by lead-in wires 16, 13. The filament 14 is electrically connected, through the lead-in wires 16, 18 to a pair of contact pins 20, 22 which project from the envelope 12. The hermetic seal of the envelope is effected by a press seal 24. The envelope 12 is further provided with a tubulation 26, shown tipped-off in the drawings, through which air is exhausted, in manufacture of the capsule 10, and an inert first fill gas including one or more halogens (i.e., iodine, bromine, chlorine and fluorine) is introduced.
The envelope 12 preferably, but not necessarily, is provided with an inner barrier layer 30 on an inside surface 32 of the envelope 12, the barrier layer 30 preferably comprising silicon dioxide. The barrier layer 30 prevents the alkaline ions of the hardglass from reaching the CA 022432~ 1998-07-16 atmosphere in the envelope 12, the halogen thereby being prevented from reacting with the hardglass alkaline ions, permitting the halogen to remain in a gaseous state and continue a tungsten-halogen regenerative cycle, well known in the art.
The envelope 12 is provided with a titania/silica infrared reflective coating 40 on an outer surface 42 of the ènvelope. The coating 40 permits passage therethrough of visible light and reflects infrared energy back towards the filament 14 such that less electrical energy is required to malntain the filament temperature at an operative level.
Referring to FIG. 2, it will be seen that the illustrative lamp includes an outer jacket 50 hermetically enclosing the capsule 10. Illustrated in FIG. 2 is outer jacket 50 in the form of a parabolic reflector 52. The reflector 52 forms a cavity 54 and includes a forward concave reflecting portion 56 and a rear neck portion 58 adjacent thereto. A skirted portion 60 of a lamp base 62 is secured to the rear neck portion 58 of reflector 52. A lamp base portion 64 includes a threaded metal shell 66 and a metal eyelet 68. Contact pins 20, 22 are electrically connected to the threaded metal shell 66 and the metal eyelet 68, respectively. A lens 70 is hermetically sealed to the reflecting portion 56.
The outer jacket 50 contains a second fill gas including oxygen. The second fill gas is a mixture of helium and oxygen, wherein the oxygen content is about 2% to CA 022432~ l998-07-l6 about 20% of the mixture, by volume, and preferably is around 5~ by volume. The second fill gas mixture is under pressure in the outer jacket 50 of no more than about 600 torr. The second fill gas insures that oxygen is present contiguous to the titania/silica outer capsule coating 40 to maintain the oxidation state of the coating 40 such that the coating 40 retains the proper visible light transmission and infrared light reflectance characteristics. The second fill gas also conducts heat away from the capsule 10, thereby operating to cool the capsule to an acceptable operating temperature.
While the use of a hardglass capsule is preferred for cost reasons, it has been found beneficial to provide the oxygen-containing fill gas in quartz and 96~ glass capsules in parabolic reflectors to insure proper visible light transmission.
There is thus provided an incandescent lamp and, particularly, a parabolic reflector lamp, wherein the tungsten-halogen capsule is provided with an outer coating of titania/silica and wherein an outer jacket hermetically encloses the capsule therein and contains a fill gas including oxygen which conducts heat from the capsule and which maintains the oxidation state of the outer coating such that the transmission of visible light from the capsule is maintained and not degraded.
There is further provided a lamp as described immediately above and further provided with a capsule inner CA 022432~ l998-07-l6 coating of silica dioxide to prevent the alkaline ions of a hardglass capsule from reacting with the halogen content of the capsule fill gas, to permit the halogen to remain in a gaseous state and react appropriately with the tungsten in a regenerative manner.
It is to be understood that the present invention is by no means limited to the particular construction herein disclosed and/or shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.
CA 022432~ l998-07-l6
The hardglass is a material having a linear coefficient of thermal expansion of from about 30 to 50 X 10-7 in/in/~C, having softening temperatures from about 750~C to about 1020~C, and having a strain point of about 650~C to about 760~C. Exemplary of such materials are the borosLlicate and aluminosilicate glasses. A suitable glass is discussed in U.S. Patents Nos. 4,060,423 and 4,105,826.
As the lamp wattage is increased and/or the size of the lamp envelope is decreased, the envelope wall temperature CA 022432~ 1998-07-16 increases, causing some of the alkaline ions of the hardglass (i.e., barium, strontium and calcium ions) to diffuse to the inner surface of the glass and/or outgas into the lamp where they interact with the halogen gas. The result is a condensation of the reacted halogen gas on inner walls of the lamp, which reduces the available halogen level in the lamp. Sufficient depletion of the halogen content in this manner can lead to failure of the halogen cycle, and blackening of the envelope wall, due to deposited tungsten.
In view of the limitations of using hardglass for the envelope of a tungsten halogen incandescent lamp, the envelope of such lamps sometimes i8 made from vitreous fused silica (i.e., quartz) or a high silica content glass, such as one composed of ninety-six per cent silica. However, quartz and ninety-six per cent silica glass are difficult to process and therefore relatively expensive. Also, lamps made of quartz require a moly foil seal which is also somewhat more difficult and expensive to fabricate.
To prevent the reaction of halogen with the lamp envelope and to alleviate the need to use quartz or 96~
silica glass, it is known to provide a tungsten-halogen incandescent lamp with an internal barrier layer of silicon dioxide (SiO2). The coating forms a continuous and glassy barrier on the inner surface of the lamp envelope which prevents alkaline ions of the hardglass of the envelope from reaching the atmosphere in the envelope. The halogen is thus prevented from reacting with the alkaline ions of the CA 022432~ 1998-07-16 hardglass, leaving the halogen in a gaseous stat:e. In U.S.
Patent No. 5,473,226 issued December 5, 1995 to Mark D.
Beschle et al, the silicon dioxide coating is discussed in detail.
It is also known to provide a tungsten-halogen incandescent lamp envelope with an external coating of infrared ray reflection material to make use of the usually wasted infrared energy emitted by incandescent lamps. The infrared ray reflection film transmits visible rays and reflects infrared rays back to the filament, thereby decreasing the energy needed to maintain the filament at its operating temperature.
In U.S. Patent No. 4,160, 929, issued July l0, 1979 to Luke Thorington et al, there is disclosed an external coating comprising three layers, including a first layer of titanium dioxide (TiO2), a second layer of silver (Ag), and a third layer of titanium dioxide.
In U.S. Patent No. 4,524,410, isgued June 18, 1985 to Akira Kawakatsu et al, there is discussed an envelope external coating comprising three layers, including a first layer of titanium dioxide (TiO2), a second layer of silica (SiO2) and a third layer of titanium dioxide. There is also discussed the use of materials other than titanium dioxide, such as zirconium dioxide (ZrO2), tantalum pentoxide (Ta2Os) and cerium dioxide (CeO2), and the use of materials other than silica, such as magnesia (MgO) and alumina (Al203). A
CA 022432~ l998-07-l6 single layered film of titanium dioxide is further suggested.
In U.S. Patent No. 5,422,534, issued June 6, 1995 to Frederick W. Dynys, there is disclosed a reflective coating for incandescent lamps, the coating including alternating layers of titania, tantala and silica.
It is known also to use a coating of alternating layers of titania and silica.
Unfortunately, when a reflective coating is used on a capsule in a parabolic reflector lamp, the capsule wall temperature can exceed the use temperature range for most hard glass formulations. When the capsule wall sustains high temperatures for long periods of time, the halogen in the capsule reacts with the capsule wall, leading to a reduction in the available halogen content, thus causing the halogen cycle to fail. Accordingly, quartz envelopes are frequently used in combination with the infrared reflective coatings in parabolic reflector lamps, making the infrared conserving products very expensive and less cost effective than they might otherwise be. To reduce the cost of the lamp substantially, it appears necessary that the capsule envelope be of hardglass rather than quartz.
It had been thought that the above-mentioned inside coating of silicon dioxide, or the like, would solve the problem by eliminating the halogen reaction with the hardglass capsule wall. While the interior barrier layer appears to have merit, it is clear that a further safeguard CA 022432~ 1998-07-16 is needed, either in place of, or in addition to, the interior barrier. It appears that the solution to the cost and halogen cycle failure problems in a tungsten-halogen capsule for a parabolic reflector lamp, wherein the capsule i9 provided with a infrared reflective outer coating, is to provide a hardglass capsule and means to cool the capsule to an operational temperature consistent with the operational temperature of a hardglass capsule without the infrared reflective coating. It has been found that filling the outer jacket with helium provides the necessary cooling effect; however, the helium fill may have the deleterious effect of reducing the titania layer on the capsule exterior. This reduction can result in a 1088 of visible transmission of the coating.
S Accordingly, there is a need to provide an incandescent lamp, and in particular, a parabolic reflector lamp, wherein a hardglass tungsten-halogen capsule is provided with an outer coating of titania-silica and wherein the visible light transmission is not degraded by reduction of the titania.
There is further a need to provide a lamp as described immediately above, wherein the outer coating may be used in conjunction with the aforesaid silicon dioxide inner coating.
CA 022432~ 1998-07-16 SUMMARY OF THE INVENTION
An object of the invention is, therefore, to provide an incandescent lamp wherein a tungsten-halogen capsule is provided with an outside coating of titania-silica and wherein visible light transmission is not degraded by reduction of the titania in the outside coating.
A further object of the invention is to provide an incandescent lamp wherein a hardglass tungsten-halogen capsule is provided with an outside coating of titania-silica.
A further object of the invention is to provide aparabolic reflector lamp including a tungsten-halogen capsule disposed in an outer jacket comprising a parabolic reflector hermetically sealed around the capsule.
A still further object of the invention is to provide an incandescent lamp wherein a tungsten-halogen capsule is provided with an outside coating of titania-silica and an inside coating of silicon dioxide.
With the above and other objects in view, as will hereinafter appear, there is provided an incandescent lamp comprising a hermetically sealed envelope, a first fill gas including halogen contained by the envelope, at least one tungsten filament sealed in the envelope and supported by lead-in wires, and a titania/silica infrared reflective coating on an outside surface of the envelope. An outer jacket encloses the envelope, the outer jacket having therein a second fill gas at a pressure of no more than CA 022432~ 1998-07-16 97-l-070 -7- PATENT APPLICATION
about 600 torr, the fill gas consisting of a mixture of helium and oxygen.
In accordance with a further feature of the invention, the capsule is of hardglass.
In accordance with a further feature of the invention the aforementioned outer jacket comprises a parabolic reflector hermetically sealed about the envelope.
In accordance with a still further feature of the invention, there is provided on an inside surface of the envelope a coating of silicon dioxide.
The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention.
The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is made to the accompanying drawings in which is shown an illustrative embodiment of the invention, from which its novel features and advantages will be apparent.
In the drawings:
CA 022432~ 1998-07-16 FIG. 1 is a sectional view of one form of incandescent capsule illustrative of an embodiment of the invention; and FIG. 2 is a partly elevational and partly sectional view showing the capsule of FIG. 1 in combination with an outer jacket comprising a parabolic reflector.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, it will be seen that an illustrative embodiment of the invention includes tungsten-halogen capsule 10 comprising a hermetically sealed envelope 12, preferably of hardglass, but alternatively of quartz, or 96~ silica glass, enclosing at least one tungsten filament 14 supported by lead-in wires 16, 13. The filament 14 is electrically connected, through the lead-in wires 16, 18 to a pair of contact pins 20, 22 which project from the envelope 12. The hermetic seal of the envelope is effected by a press seal 24. The envelope 12 is further provided with a tubulation 26, shown tipped-off in the drawings, through which air is exhausted, in manufacture of the capsule 10, and an inert first fill gas including one or more halogens (i.e., iodine, bromine, chlorine and fluorine) is introduced.
The envelope 12 preferably, but not necessarily, is provided with an inner barrier layer 30 on an inside surface 32 of the envelope 12, the barrier layer 30 preferably comprising silicon dioxide. The barrier layer 30 prevents the alkaline ions of the hardglass from reaching the CA 022432~ 1998-07-16 atmosphere in the envelope 12, the halogen thereby being prevented from reacting with the hardglass alkaline ions, permitting the halogen to remain in a gaseous state and continue a tungsten-halogen regenerative cycle, well known in the art.
The envelope 12 is provided with a titania/silica infrared reflective coating 40 on an outer surface 42 of the ènvelope. The coating 40 permits passage therethrough of visible light and reflects infrared energy back towards the filament 14 such that less electrical energy is required to malntain the filament temperature at an operative level.
Referring to FIG. 2, it will be seen that the illustrative lamp includes an outer jacket 50 hermetically enclosing the capsule 10. Illustrated in FIG. 2 is outer jacket 50 in the form of a parabolic reflector 52. The reflector 52 forms a cavity 54 and includes a forward concave reflecting portion 56 and a rear neck portion 58 adjacent thereto. A skirted portion 60 of a lamp base 62 is secured to the rear neck portion 58 of reflector 52. A lamp base portion 64 includes a threaded metal shell 66 and a metal eyelet 68. Contact pins 20, 22 are electrically connected to the threaded metal shell 66 and the metal eyelet 68, respectively. A lens 70 is hermetically sealed to the reflecting portion 56.
The outer jacket 50 contains a second fill gas including oxygen. The second fill gas is a mixture of helium and oxygen, wherein the oxygen content is about 2% to CA 022432~ l998-07-l6 about 20% of the mixture, by volume, and preferably is around 5~ by volume. The second fill gas mixture is under pressure in the outer jacket 50 of no more than about 600 torr. The second fill gas insures that oxygen is present contiguous to the titania/silica outer capsule coating 40 to maintain the oxidation state of the coating 40 such that the coating 40 retains the proper visible light transmission and infrared light reflectance characteristics. The second fill gas also conducts heat away from the capsule 10, thereby operating to cool the capsule to an acceptable operating temperature.
While the use of a hardglass capsule is preferred for cost reasons, it has been found beneficial to provide the oxygen-containing fill gas in quartz and 96~ glass capsules in parabolic reflectors to insure proper visible light transmission.
There is thus provided an incandescent lamp and, particularly, a parabolic reflector lamp, wherein the tungsten-halogen capsule is provided with an outer coating of titania/silica and wherein an outer jacket hermetically encloses the capsule therein and contains a fill gas including oxygen which conducts heat from the capsule and which maintains the oxidation state of the outer coating such that the transmission of visible light from the capsule is maintained and not degraded.
There is further provided a lamp as described immediately above and further provided with a capsule inner CA 022432~ l998-07-l6 coating of silica dioxide to prevent the alkaline ions of a hardglass capsule from reacting with the halogen content of the capsule fill gas, to permit the halogen to remain in a gaseous state and react appropriately with the tungsten in a regenerative manner.
It is to be understood that the present invention is by no means limited to the particular construction herein disclosed and/or shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.
CA 022432~ l998-07-l6
Claims (20)
1. An incandescent lamp comprising:
a hermetically sealed envelope;
a first fill gas including halogen contained by said envelope;
at least one tungsten filament sealed in said envelope and supported by lead-in wires;
a titania/silica infrared reflective coating on an outside surface of said envelope; and an outer jacket enclosing said envelope, said outer jacket having therein a second fill gas including oxygen.
a hermetically sealed envelope;
a first fill gas including halogen contained by said envelope;
at least one tungsten filament sealed in said envelope and supported by lead-in wires;
a titania/silica infrared reflective coating on an outside surface of said envelope; and an outer jacket enclosing said envelope, said outer jacket having therein a second fill gas including oxygen.
2. The lamp in accordance with claim 1 wherein said envelope is of hardglass.
3. The lamp in accordance with claim 1 wherein said envelope is of ninety-six percent silica glass.
4. The lamp in accordance with claim 1 wherein said envelope is of quartz.
5. The lamp in accordance with claim 1 wherein said outer jacket comprises a hermetically sealed parabolic reflector.
6. The lamp in accordance with claim 1 wherein said second fill gas includes helium and comprises about 2-20% oxygen by volume.
7. The lamp in accordance with claim 6 wherein said second fill gas comprises about 5% oxygen by volume.
8. The lamp in accordance with claim 1 wherein said lamp further comprises an interior barrier layer on an inside surface of said envelope, said barrier layer comprising silicon dioxide.
9. The lamp in accordance with claim 1 wherein said second fill gas in said outer jacket is at a pressure of no more than about 600 torr.
10. The lamp in accordance with claim 2 wherein said outer jacket comprises a hermetically sealed reflector.
11. The lamp in accordance with claim 10 wherein said second fill gas includes helium and comprises about 2-20%
oxygen by volume.
oxygen by volume.
12. The lamp in accordance with claim 11 wherein said second fill gas comprises about 80-98% helium by volume.
13. The lamp in accordance with claim 12 wherein said second fill gas comprises about 5% oxygen by volume and about 95% helium by volume.
14. The lamp in accordance with claim 12 wherein said lamp further comprises an interior barrier layer on an inside surface of said envelope to prevent alkaline ions of said hardglass from reaching the atmosphere in said capsule.
15. The lamp in accordance with claim 1 wherein said oxygen is present in said second fill gas to an extent necessary to maintain an oxidation state of said titania-silica coating.
16. The lamp in accordance with claim 12 wherein said second fill gas in said outer jacket is at a pressure of no more than about 600 torr.
17. The lamp in accordance with claim 1 wherein said envelope is of hardglass and said outer jacket comprises a sealed parabolic reflector.
18. The lamp in accordance with claim 17 wherein said second fill gas includes about 5% oxygen by volume.
19. The lamp in accordance with claim 18 wherein said second fill gas includes about 95% helium by volume.
20. The lamp in accordance with claim 19 wherein said lamp further comprises an interior barrier layer on an inside surface of said envelope, said barrier layer comprising silicon dioxide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US99274097A | 1997-12-17 | 1997-12-17 | |
| US08/992,740 | 1997-12-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2243255A1 true CA2243255A1 (en) | 1999-06-17 |
Family
ID=29420978
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2243255 Abandoned CA2243255A1 (en) | 1997-12-17 | 1998-07-16 | Incandescent lamp having tungsten-halogen capsule with titania/silica external infrared reflective coating and oxygen-filled outer jacket |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2243255A1 (en) |
-
1998
- 1998-07-16 CA CA 2243255 patent/CA2243255A1/en not_active Abandoned
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