INCANDESCENT LAMP INCORPORATING REFLECTIVE FILAMENT SUPPORTS AND METHOD FOR MAKING IT

• US 20100327724A1
• Filed: 06/24/2010
• Published: 12/30/2010
• Est. Priority Date: 06/24/2009
• Status: Active Grant

• Current Assignee: David W. Cunningham
• Original Assignee: David W. Cunningham
• Inventors: Cunningham, David W.
• Granted Patent: US 8,253,309 B2
• Time in Patent Office: Days
• US Class Current: 313/45
• CPC Class Codes: H01K 1/18 Mountings or supports for the incandescent body
• CPC Class Codes: H01K 1/26 Screens; Filters associated with envelope H01K1/28
• CPC Class Codes: H01K 1/325 Reflecting coating

Abstract

An improved incandescent lamp and incandescent lighting system are disclosed, for projecting a beam of light with substantially improved energy efficiency. The incandescent lamp includes a pair of reflective ceramic filament supports for supporting one or more filaments in prescribed position(s) within an envelope while reflecting back substantially all visible and infrared light for incorporation into the projected beam or for absorption by the filament(s).

Claims

1. An incandescent lamp comprising:

an envelope having a closed interior space and a longitudinal axis;

one or more filaments located in the interior space of the envelope; and

forward and rearward filament supports positioned in the interior space of the envelope, with the one or more filaments disposed between them, wherein each filament support comprises a block of material extending transversely across substantially the entire interior space of the envelope and having an average total reflectance of at least 90% across a wavelength range of 500 to 2000 nanometers.

2. The incandescent lamp as defined in claim 1, wherein:

the portion of the envelope surrounding the one or more filaments and the forward and rearward filament supports has a substantially cylindrical shape; and

the forward and rearward filament supports each have a substantially cylindrical side wall sized to fit snugly within the envelope.

3. The incandescent lamp as defined in claim 1, wherein the forward and rearward filament supports each include a face that faces the one or more filaments and reflects light received from the one or more filaments back toward the one or more filaments, the face of the other filament support, or the portion of the envelope located radially outward of the one or more filaments.

4. The incandescent lamp as defined in claim 6, wherein the faces of the forward and rearward filament supports both provide diffuse reflection of light received from the one or more filaments.

5. The incandescent lamp as defined in claim 3, wherein a portion of each of the forward and rearward filament supports, other than its face, has a grooved configuration, to increase its heat dissipation.

6. The incandescent lamp as defined in claim 1, wherein the forward and rearward filament supports both are formed primarily of a porous ceramic material having a porosity of 10% or less.

7. The incandescent lamp as defined in claim 6, wherein the porous ceramic material is selected from the group consisting of alumina, zirconia, magnesia, and mixtures thereof.

8. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports both are substantially alkali- and hydroxyl-free and have a calcia concentration of less than or equal to 80 parts per million.

9. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports both are substantially alkali- and hydroxyl-free and have a calcia concentration of less than or equal to 20 parts per million.

10. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports both are substantially alkali- and hydroxyl-free and have a calcia concentration of less than or equal to 10 parts per million.

11. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports both have a grain size distribution ranging from about 1-50 microns and an average grain size in the range of about 5-15 microns.

12. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports both have a pore size distribution ranging from about 0.2-20 microns and an average pore size in the range of about 2-6 microns.

13. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports both have a density in the range of about 92-98% of their theoretical maximum density.

14. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports both have a density in the range of about 93-97% of their theoretical maximum density.

15. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports both have a closed porosity or open porosity of less than about 1%.

16. The incandescent lamp as defined in claim 6, wherein the forward and rearward filament supports have a closed porosity or open porosity of less than about 0.5%.

17. The incandescent lamp as defined in claim 6, wherein each of the forward and rearward filament supports further includes an emissive coating having a peak emissivity at a wavelength in the range of about 2-4 microns.

18. The incandescent lamp as defined in claim 1, wherein the lamp is free of any support structure located in the interior space of the envelope, radially outward of the one or more filaments.

19. The incandescent lamp as defined in claim 1, and further comprising one or more elongated supports extending between the forward and rearward filament supports and oriented substantially parallel with the longitudinal axis of the envelope, wherein the elongated supports are substantially transparent in the wavelength range of about 500 to 2500 nanometers.

20. The incandescent lamp as defined in claim 1, wherein:

the envelope includes forward and rearward pinched ends;

the forward filament support is located adjacent to the forward pinched end and substantially fills the interior space of the envelope between the one or more filaments and the forward pinched end; and

the rearward filament support is located adjacent to the rearward pinched end and substantially fills the interior space of the envelope between the one or more filaments and the rearward pinched end.

21. The incandescent lamp as defined in claim 1, wherein:

the envelope includes forward and rearward pinched ends;

the forward filament support is located adjacent to the forward pinched end;

the rearward filament support is located adjacent to the rearward pinched end; and

the incandescent lamp further comprises a halogen-compatible filler material substantially filling the space within the envelope between the forward filament support and the forward pinched end and between the rearward filament support and the rearward pinched end.

23. The incandescent lamp as defined in claim 1, wherein:

the one or more filaments include only two substantially identical linear filaments connected together in series by an intervening loop;

the incandescent lamp further includes two power leads connected to the opposite ends of the series-connected filaments and a support hook for supporting the loop connecting the two filaments;

the rearward filament support includes two lead apertures, each sized to slidably receive a separate one of the two power leads;

the forward filament support includes a support hook aperture configured to support the support hook; and

the locations of the lead apertures and the support hook aperture positioning the two filaments in prescribed positions in the interior space of the envelope, with their linear axes substantially parallel to, and on opposite sides of, the longitudinal axis of the envelope.

24. The incandescent lamp as defined in claim 1, wherein:

the one or more filaments include an odd number of three or more substantially identical linear filaments connected together in series by intervening loops;

the incandescent lamp further includes

two power leads connected to the opposite ends of the series-connected filaments, and

a plurality of support hooks, each supporting one of the loops connecting adjacent filaments of the three or more filaments;

the forward and rearward filament supports each include a lead aperture, each sized to slidably receive a separate one of the two power leads;

the forward and rearward filament supports together include a plurality of support hook apertures, each configured to support a separate one of the plurality of support hooks; and

the locations of the lead apertures and the support hook apertures positioning the three or more filaments in prescribed positions in the interior space of the envelope, with their linear axes substantially parallel to, and spaced around, the longitudinal axis of the envelope.

25. The incandescent lamp as defined in claim 1, wherein:

the one or more filaments include an even number of four or more substantially identical linear filaments connected together in series by intervening loops;

the incandescent lamp further includes

two power leads connected to the opposite ends of the series-connected filaments, and

a plurality of support hooks, supporting one of the loops connecting adjacent filaments of the four or more filaments;

the rearward filament support includes two lead apertures, each sized and configured to slidably receive a separate one of the two power leads;

the forward and rearward filament supports together further include a plurality of support hook apertures, each configured to support a separate one of the plurality of support hooks; and

the locations of the lead apertures and the support hook apertures positioning the four or more filaments in prescribed positions in the interior space of the envelope, with their linear axes substantially parallel to, and spaced around, the longitudinal axis of the envelope.

27. The incandescent lamp as defined in claim 1, wherein:

the incandescent lamp further comprises two power leads associated with the one or more filaments;

the forward filament support and/or the rearward filament support include separate lead apertures for slidably receiving the two power leads; and

the location of each of the lead apertures positions one end of the adjacent filament in a prescribed position in the interior space of the envelope.

28. The incandescent lamp as defined in claim 27, wherein an end portion of each of the power lead apertures has a transverse dimension substantially larger than that of the power lead extending through it.

29. The incandescent lamp as defined in claim 27, and further comprising segments of tungsten wire wrapped around each of the two power leads, adjacent to the ends of the power lead apertures, for securing the associated forward or rearward filament support in its prescribed position in the interior space of the envelope.

30. The incandescent lamp as defined in claim 29, wherein:

each of the power leads is a separate tungsten rod;

each of the power lead apertures includes an enlarged end portion having a transverse dimension substantially larger than that of the power lead extending through it; and

the end of the filament adjacent to each power lead is wrapped around the power lead in the enlarged end portion of its associated power lead aperture.

31. The incandescent lamp as defined in claim 1, wherein each of the forward and rearward filament supports includes a channel for allowing gas to migrate between the space surrounding the one or more filaments and the space within the envelope on the side of the filament support opposite the one or more filaments.

32. The incandescent lamp as defined in claim 31, wherein the channel in each of the forward and rearward filament supports is located in a radially outward-facing surface of the filament support.

33. The incandescent lamp as defined in claim 1, wherein the forward and rearward filament supports each comprise a block of material having an average total reflectance of at least 95% across a wavelength range of 500 to 2000 nanometers.

22. The incandescent lamp as defined in claim wherein:

the one or more filaments includes only a single linear filament;

the incandescent lamp further comprises two power leads associated with the filament;

the forward filament support and the rearward filament support each include a lead aperture for slidably receiving one of the two power leads; and

the locations of the lead apertures in the forward and rearward filament supports positions the filament in a prescribed position in the interior space of the envelope, with its linear axis substantially aligned with the longitudinal axis of the envelope.

26. (canceled)

34. An incandescent lamp comprising:

an envelope having a closed interior space and a longitudinal axis;

one or more filaments located in the interior space of the envelope and extending along, or parallel with, the longitudinal axis; and

forward and rearward filament supports positioned in the interior space of the envelope, with the one or more filaments disposed between them;

wherein the lamp is free of any support structure located in the interior space of the envelope, radially outward of the one or more filaments.

35. An incandescent lamp comprising:

an envelope having a closed interior space and a longitudinal axis;

one or more filaments located in the interior space of the envelope and extending along, or parallel with, the longitudinal axis;

forward and rearward filament supports positioned in the interior space of the envelope, with the one or more filaments disposed between them; and

one or more elongated supports extending between the forward and rearward filament supports and oriented substantially parallel with the longitudinal axis, wherein the one or more elongated supports are substantially transparent in the wavelength range of about 500 to 2500 nanometers;

wherein the lamp is free of any support structure located in the interior space of the envelope, radially outward of the one or more filaments, other than the one or more transparent supports.

36. An incandescent lamp comprising:

an envelope having a closed interior space and a longitudinal axis;

one or more filaments connected together in series and located in the interior space of the envelope and extending along, or parallel with, the longitudinal axis;

two power leads associated with the one or more filaments;

forward and rearward filament supports positioned in prescribed positions in the interior space of the envelope, with the one or more filaments disposed between them;

wherein the forward filament support and/or the rearward filament support include separate power lead apertures for slidably receiving and supporting the two power leads; and

segments of tungsten wire wrapped around each of the two power leads, adjacent to the ends of the power lead apertures, for securing the associated forward or rearward filament support in its prescribed position in the interior space of the envelope.

37. An incandescent lamp comprising:

an envelope having a closed interior space and a longitudinal axis;

a linear filament located in the interior space of the envelope;

two power leads; and

forward and rearward filament supports slidably received in prescribed positions in the interior space of the envelope, adjacent opposite ends of the filament;

wherein the forward and rearward filament supports each include a power lead aperture for slidably receiving and supporting one of the two power leads, the locations of the lead apertures in the forward and filament supports positioning the linear filament with its linear axis aligned with the longitudinal axis of the envelope.

38. An incandescent lamp comprising:

an envelope having a closed interior space and a longitudinal axis;

an even number of four or more linear filaments connected together serially by loops and located in the interior space of the envelope;

forward and rearward filament supports slidably received in prescribed positions in the interior space of the envelope, with the filaments located between them;

two power leads; and

a plurality of support hooks, for supporting the loops connecting adjacent filaments of the series-connected filaments; and

wherein the rearward filament support includes separate power lead apertures for slidably receiving and supporting the two power leads;

wherein the forward and rearward filament supports together further include support hook apertures for supporting the plurality of support hooks; and

wherein the locations of the power lead apertures and the support hook apertures position the filaments in prescribed positions in the interior space of the envelope, with their linear axes spaced around, and parallel with, the longitudinal axis of the envelope.

39. A method for making an incandescent lamp for use in combination with a lighting fixture to project a beam of light, the method comprising steps of:

providing an unsealed, elongated envelope having an interior space;

providing two leads;

providing forward and rearward filament supports, the filament supports together including two apertures, each for slidably receiving and supporting a separate one of the two leads;

providing one or more filaments;

mounting the one or more filaments to the forward and rearward filament supports, with the one or more filaments disposed between them;

slidably positioning the forward and rearward filament supports, with the one or more filaments mounted thereto, in the interior space of the envelope; and

sealing the envelope.

40. The method as defined in claim 39, wherein:

the forward and rearward filament supports both comprise a block of reflective ceramic material having a porosity of 10% or less and sized and configured to extend transversely across substantially the entire interior space of the envelope;

the step of providing forward and rearward filament supports comprises a step of molding each the forward and rearward filament supports as a single, unitary structure; and

the step of providing forward and rearward filament supports further comprises a step of sintering the forward and rearward filament supports prior to the step of slidably positioning.

41. The method as defined in claim 39, wherein:

the forward andrearward filament supports each define a channel for allowing a gas to migrate past it after the filament supports have been slidably positioned in the interior space of the envelope; and

the step of sealing the envelope includes the steps of;

pumping a non-reacting gas through the interior space of the envelope and the channel of the forward filament support while pinching closed the forward end of the envelope, and

pumping a non-reacting gas through the interior space of the envelope and the channel of the rearward filament support while pinching closed the rearward end of the envelope.

42. The method as defined in claim 41, wherein:

the method further includes the step of providing an exhaust port in the envelope;

the channel defined in at least one of the forward and rearward filament supports is located in an outward-facing surface of the filament support;

the step of slidably positioning the forward and rearward filament supports includes a step of aligning the channel defined in the outward-facing surface of one of the filament supports with the exhaust port; and

the two steps of pumping a non-reacting gas each include a step of directing the gas through the exhaust port.

43. The method as defined in claim 41, wherein:

the one or more filaments include a plurality of filaments;

the two lead apertures both are located in the rearward filament support; and

the second step of pumping while pinching closed the rearward end of the envelope occurs after the first step of pumping while pinching closed the forward end of the envelope, and it is accompanied by a step of applying a tensile force to the two leads and, in turn, to the plurality of filaments.