US4160929A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Incandescent light source with transparent heat mirror
Assignee: Duro Test Corp
•
Filing: 1977-03-25
•
Granted: 1979-07-10
•
Expires: 1997-03-25
Abstract
Abstract An incandescent lamp having a transparent heat mirror placed on the lamp envelope which transmits a substantial portion of the energy in the visible range produced by the lamp filament and which reflects back to the filament at least about 80%-85% of the infrared energy that the filament produces. In the preferred embodiment the transparent heat mirror is formed by a layered coating of TiO 2 /Ag/TiO 2 optimized for the operating temperature range of the filament. The filament is constructed to optically conform to the shape of the lamp envelope.
Inventors
- 👤 Luke Thorington
- 👤 Peter Walsh
- 👤 Ronald Koo
- 👤 Wolfgang Thouret
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:57
CPC Classifications
H; H01; H01K; H01K1/00; H01K1/28; H01K1/32
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
237 words
An incandescent electric lamp comprising: an envelope, incandescent filament means within said envelope for producing upon incandescence energy in the visible and infrared range upon the application of electrical current thereto, means electrically connected to said filament means adapted for supplying electrical current thereto, said filament means being located with respect to the interior of the envelope and the major portion of said envelope being shaped with a curved surface such that infrared energy produced by said filament means upon incandescence and reaching the envelope can be reflected back toward said filament means, and a transparent heat mirror coating on a major portion of said envelope curved surface said envelope formed by a layer of a high conductivity metal which is thick enough to reflect infrared energy and thin enough to transmit visible energy and at least one layer of a dielectric material thereon whose index of refraction of the energy in the visible range substantially matches the index of absorption of the metal in the visible range, said coating for reflecting back towards the filament at least an average in excess of about 60% of the energy over the infrared range produced by said filament means and for transmitting therethrough an average in excess of about 60% of the energy over the visible range produced by said filament means which reaches said coating said dielectric material providing phase matching to the visible energy for the metal.
Claim 2
Dependent Claim
237 words
An incandescent electric lamp comprising: an envelope, incandescent filament means within said envelope for producing upon incandescence energy in the visible and infrared range upon the application of electrical current thereto, means electrically connected to said filament means adapted for supplying electrical current thereto, said filament means being located with respect to the interior of the envelope and the major portion of said envelope being shaped with a curved surface such that infrared energy produced by said filament means upon incandescence and reaching the envelope can be reflected back toward said filament means, and a transparent heat mirror coating on a major portion of said envelope curved surface said envelope formed by a layer of a high conductivity metal which is thick enough to reflect infrared energy and thin enough to transmit visible energy and at least one layer of a dielectric material thereon whose index of refraction of the energy in the visible range substantially matches the index of absorption of the metal in the visible range, said coating for reflecting back towards the filament at least an average in excess of about 60% of the energy over the infrared range produced by said filament means and for transmitting therethrough an average in excess of about 60% of the energy over the visible range produced by said filament means which reaches said coating said dielectric material providing phase matching to the visible energy for the metal.
Claim 3
Dependent Claim
66 words
An incandescent electric lamp as in claim 1 wherein said coating is formed so that of the energy reaching it the ratio of transmission through said coating of the average of the energy over the visible light range produced by the filament to the transmission of the average of the energy over the infrared range produced by said filament is at least about 3 to 1.
Claim 4
Dependent Claim
18 words
An incandescent electric lamp as in claim 2 wherein said ratio is at least about 4 to 1.
Claim 5
Dependent Claim
46 words
An incandescent electric lamp as in claim 3 wherein said filament has an operating temperature in the range of from about 2600° K. to about 2900° K. and said coating is optimized for the transmission of visible and reflection of infrared energy in this temperature range.
Claim 6
Dependent Claim
53 words
An incandescent electric lamp as in claim 1 wherein said coating transmits therethrough at least about 60% of the average of the energy over the visible range reaching it and reflects back towards the filament at least about 80% to 85% of the average of the energy over the infrared range reaching it.
Claim 7
Dependent Claim
23 words
An incandescent electric lamp as in claim 1 wherein the metal is selected from the group consisting of silver, rubidium, sodium and potassium.
Claim 8
Dependent Claim
56 words
An incandescent electric lamp as in claim 1 wherein said coating comprises a layer of metal sandwiched between and contiguous with layers of dielectric material, each of said layers of dielectric material having an index of refraction of energy in the visible range which substantially matches the imaginary part of the reflective index of the metal.
Claim 9
Dependent Claim
66 words
An incandescent electric lamp as in claim 7 wherein said coating is formed so that of the energy reaching it the ratio of transmission through said coating of the average of the energy over the visible light range produced by the filament to the transmission of the average of the energy over the infrared range produced by said filament is at least about 3 to 1.
Claim 10
Dependent Claim
18 words
An incandescent electric lamp as in claim 8 wherein said ratio is at least about 4 to 1.
Claim 11
Dependent Claim
53 words
An incandescent electric lamp as in claim 7 wherein said coating transmits therethrough at least about 60% of the average of the energy over the visible range reaching it and reflects back towards the filament at least about 80% to 85% of the average of the energy over the infrared range reaching it.
Claim 12
Dependent Claim
24 words
An incandescent electric lamp as in claim 10 wherein the metal is selected from the group consisting of gold, silver, rubidium, sodium and potassium.
Claim 13
Dependent Claim
25 words
An incandescent electric lamp as in claim 7 wherein said layer of metal comprises silver and said layers of dielectric material each comprises titanium dioxide.
Claim 14
Dependent Claim
26 words
An incandescent electric lamp as in claim 12 wherein the ratio of the thickness of the layers of the dielectric materials is substantially 1 to 1.
Claim 15
Dependent Claim
34 words
An incandescent electric lamp as in claim 12 wherein the ratio of the thickness of the layer of the dielectric material closest to the filament to that furtherest from the filament is substantially 1:3.
Claim 16
Dependent Claim
69 words
An incandescent electric lamp as in claim 12 wherein said filament has an operating temperature in the range of from about 2600° K. to about 2900° K. and said layers of the coating having the following thicknesses: ______________________________________
Thickness (in nanometers)
from about
to about
______________________________________
inner layer of dielectric
material closest to filament
13 28
layer of metal 13 28
outer layer of dielectric material
13 28
______________________________________
Claim 17
Dependent Claim
69 words
An incandescent electric lamp as in claim 12 wherein said filament has an operating temperature in the range of from about 2600° K. to about 2900° K. and said layers of the coating having the following thicknesses: ______________________________________
Thickness (in nanometers)
from about
to about
______________________________________
inner layer if dielectric
material closest to filament
13 28
layer of metal 4 9
outer layer of dielectric material
39 84
______________________________________
Claim 18
Dependent Claim
45 words
An incandescent electric lamp as in claim 7 wherein said filament has an operating temperature in the range from about 2600° K. to about 2900° K. and said coating is optimized for the transmission of visible and reflection of infrared energy in this temperature range.
Claim 19
Dependent Claim
44 words
An incandescent electric lamp as in claim 1 wherein said filament is constructed so that at least about 50% of the average of the energy in infrared range reflected from the envelope and the coating back toward the filament is incident onto said filament.
Claim 20
Dependent Claim
44 words
An incandescent electric lamp as in claim 18 wherein said filament is constructed so that at least about 60% of the average of the energy in infrared range reflected from the envelope and the coating back toward the filament is incident onto said filament.
Claim 21
Dependent Claim
49 words
An incandescent electric lamp as in claim 1 wherein said filament is formed of a wire which is triple coiled and physically formed to approximate the geometry of the reflecting portion of the envelope and being located substantially at the optical center of the reflecting portion of the envelope.
Claim 22
Dependent Claim
35 words
An incandescent electric lamp as in claim 20 wherein said filament is shaped to radiate a pattern of energy which substantially conforms to the shape of the surface of the reflecting portion of the envelope.
Claim 23
Dependent Claim
25 words
An incandescent electric lamp as in claim 21 wherein the reflecting portion of said envelope is generally cylindrical and said filament is also generally cylindrical.
Claim 24
Dependent Claim
31 words
An incandescent electric lamp as in claim 21 wherein the reflecting portion of said envelope is generally spherical and said filament is formed to physically approximate the shape of a sphere.
Claim 25
Dependent Claim
22 words
An incandescent lamp as in claim 1 wherein there is a layer of dielectric material on each side of said metal layer.
Claim 26
Dependent Claim
66 words
An incandescent lamp as in claim 24 wherein said coating reflects back toward said filament means at least an average in excess of about 80% of the energy over the infrared range above about 700 nm produced by the filament and transmits at least an average in excess of about 60% of the energy in the visible range between about 400 nm to about 700 nm.
Claim 27
Dependent Claim
27 words
An incandescent lamp as in claim 25 wherein said filament means operates upon incandescence in the temperature range of from about 2600° K. to about 2900° K.
Claim 28
Dependent Claim
23 words
An incandescent lamp as in claim 26 wherein the material of the dielectric layers in titanium dioxide and the metal layer is silver.
Claim 29
Dependent Claim
32 words
An incandescent lamp as in claim 24 wherein the thickness of each layer of the coating is one-tenth or less than the wavelength of the lowest wavelength visible light to be transmitted.
Claim 30
Dependent Claim
127 words
An incandescent electric lamp comprising a spherical shaped envelope with an elongated neck portion, an incandescent filament within said envelope for producing upon incandescence energy in the visible and infrared range upon application of electrical current thereto, means electrically connected to said filament adapted for supplying electrical current thereto, a coating on the spherical portion of the envelope for reflecting back to the filament at least a part of the infrared energy produced by said filament and for transmitting therethrough a substantial portion of the visible range energy produced by said filament, said reflector means adjacent said neck portion having substantially the same radius of curvature as the spherical portion of said envelope and located with respect to said envelope spherical portion to conform to its contour.
Claim 31
Dependent Claim
127 words
An incandescent electric lamp comprising a spherical shaped envelope with an elongated neck portion, an incandescent filament within said envelope for producing upon incandescence energy in the visible and infrared range upon application of electrical current thereto, means electrically connected to said filament adapted for supplying electrical current thereto, a coating on the spherical portion of the envelope for reflecting back to the filament at least a part of the infrared energy produced by said filament and for transmitting therethrough a substantial portion of the visible range energy produced by said filament, said reflector means adjacent said neck portion having substantially the same radius of curvature as the spherical portion of said envelope and located with respect to said envelope spherical portion to conform to its contour.
Claim 32
Dependent Claim
47 words
An incandescent electric lamp as in claim 29 wherein said reflector means is spaced from a continuation of the inner surface of the spherical portion of the envelope in the neck portion and has a radius of curvature to reflect the infrared energy back to the filament.
Claim 33
Dependent Claim
20 words
An incandescent electric lamp as in claim 29 wherein said reflector means includes a metallized surface having a metal thereon.
Claim 34
Dependent Claim
26 words
An incandescent electric lamp as in claim 31 wherein the metal of said metallized surface is selected from the group consisting of aluminum, silver and gold.
Claim 35
Dependent Claim
36 words
An incandescent electric lamp as in claim 29 wherein a stem is provided in the neck portion of the envelope on which said filament is mounted, and means for attaching said reflector means to said stem.
References Cited (Backward Citations)
US1425967A
Cited
GB452127A
Cited
US2084999A
Cited
GB703127A
Cited
US2859369A
Cited
GB834087A
Cited
US3209188A
Cited
GB1017828A
Cited
GB1463939A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-07-09 | 1983-01-08 | 1983-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-09 | 1987-01-08 | 1987-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-09 | 1991-01-08 | 1991-07-10 | $7700.00 | Window Closed / Lapsed |