JPH05205705A - Integrally supported filament and incandescent lamp - Google Patents

Abstract

PURPOSE: To integrally form a filament to be arranged inside a glass envelope of an incandescent lamp with its support part. CONSTITUTION: A plurality of filament segments 24 and integrated support parts 26 are formed of a continuous filament wire. The supported parts are ring-shaped or coil-shaped, its diameter is larger than the filament segments so that the support parts are adjacent to the inner surface of an envelope 12 of a lamp, and the filament is supported in the envelope.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has an integral support,
It relates to a refractory metal filament used in a light bulb.
More particularly, the present invention relates to an elongated continuous tungsten wire filament having a plurality of light emitting segments connected by a plurality of integral supports, and
An elongated incandescent light bulb using the filament, the support contacting the inner surface of the bulb envelope to support the filament inside the envelope.

[0002]

BACKGROUND OF THE INVENTION Incandescent light bulbs having an elongated light transmissive, generally tubular body surrounding a coiled filament therein are well known to those having skill in the art and have been in use for over 30 years. It has been done. This type of bulb is used not only for general lighting applications indoors and outdoors, but also for special applications such as heating bulbs and reprographic bulbs. The filament, which is still made of tungsten, is arranged longitudinally within the bulb, its longitudinal axis approximately coinciding with the longitudinal axis of the bulb envelope, and the filament is one of the filament supports which is not part of the filament. , Generally held in place by a plurality of filament supports. The center of each filament support is attached to the filament coil, and the outer periphery of the support contacts the inner surface of the bulb envelope to hold the filament in place. Typical filament supports are disclosed, for example, in US Pat. Nos. 3,736,455, 3,784,865 and 3,392,299. Supporting the filament within the long bulb envelope by the filament support, which is not an integral part of the filament itself, means the manufacture, use and assembly of filaments and additional components which increase the cost of the bulb in which the filament is used. In the case of incandescent bulbs, such supports are often spirals of niobium or tantalum, which are expensive and difficult to assemble on filaments. More recently, filaments with multiple diameters have been described in US Pat. No. 4,959,
No. 585, in which one diameter of the winding has a diameter large enough to contact the inner wall of the bulb envelope to axially support the filament within the bulb envelope, and The longitudinal axis of the filament coincides with the longitudinal axis of the bulb envelope.

[0003]

SUMMARY OF THE INVENTION Incandescent bulb filaments with integral filament support are formed from a single filament wire and are generally elongated or have multiple filament segments and integral support formed as part of the filament. It has a linear coiled or non-coiled filament. In one embodiment, the filament is an elongated coil having a plurality of filament coil segments and integral filament support. In other embodiments, some of the filament segments are straight wire segments and some are elongated coil segments. In yet another embodiment, all of the filament segments are straight wire segments separated by integral filament supports. In all of these examples, the integral filament support is independent of whether the filament segment is coiled, a straight wire, or has both a coil and a straight wire segment. It is provided between adjacent filament segments (but not always between all adjacent segments). The integral support is generally spiral or ring-shaped. However, if desired, the integral support may be of other shapes, such as an ellipse, a partial ring, a hexagon, a rectangle, a polygon such as a triangle, or the like. Finally, those skilled in the art will appreciate that the filament support, like the filament, produces heat and light.

[0004]

DETAILED DESCRIPTION In one embodiment, the filament of the present invention has a longitudinal axis that is radially centered with respect to a wire winding having both filament segments and integral supports. In this embodiment, the integral support supports the filament within the filament chamber of the bulb, the longitudinal axis of the filament being coincident with the longitudinal axis of the filament chamber of tubular or other shape. The filament chamber is formed symmetrically around its longitudinal axis. In embodiments in which the longitudinal axis of the filament segment does not coincide with the longitudinal axis of the support, the longitudinal axis of the filament segment does not coincide with the longitudinal axis of the filament chamber of the bulb. The filament chamber is formed symmetrically around its longitudinal axis.

The filaments of the present invention are formed from a single filament wire, preferably a refractory metal wire, more preferably a tungsten wire. Continuous wire filament in the context of the present invention means a continuous, unbroken refractory metal wire formed into a filament including a filament support. Therefore, the filament support is an integral part of the filament. Further, the supports may be of various shapes as described above, but are more generally ring-shaped, spiral-shaped or coil-shaped and have a substantially larger diameter (or non-circular support than the filament segments). In some cases have an equivalent diameter). By substantially larger diameter is meant that the diameter of the integral support is at least twice the diameter of the filament segment, and more generally at least three times. A plurality of filament segments and an integral support means that the filament according to the invention has at least two, preferably at least three filament segments and at least two, preferably at least three integral filament supports. It means that In one embodiment, the filament comprises a plurality of coiled filament segments having a substantially uniform diameter and a filament support, the filament support being provided to separate the filament segments, the filament support having a diameter of the filament support. Substantially larger than the diameter of the segment,
As shown, there is a sharp change in diameter between the filament segment and the support.

Referring now to FIG. 1, a double ended tubular quartz heating bulb 10 has a fused quartz envelope 12, which envelope 12 is a filament chamber 1.
3 and the molybdenum foil sealing portion 16 has a pressing sealing portion 14 at each end pressed. One end of the foil sealing portion 16 is connected to the outer lead wire 18 of the light bulb, and the other end is connected to the straight wire portion 20 of the filament 22. Filament 22 is formed of a single unbroken, suitable refractory metal wire. In this example, the metal wire is tungsten. The filament 22 is composed of a series of coiled filament segments 24 connected by an integral spiral support 26. The support 26 axially supports the filament within the envelope 12, with the longitudinal axis of the filament 22 coinciding with the longitudinal axis of the bulb 10. The longitudinal axis of filament 22 is centered radially with respect to the turns of both filament segment 24 and support 26.
The diameter of the integral support portion 26 is the filament segment 24.
Substantially larger than the diameter of the filament chamber 13 and sufficiently large so that the outer surface of each support is adjacent or close to the inner surface of the filament chamber 13. Both ends of the filament 22 are straight wire portions 20, and the straight wire portions 20 are connected to one end of the molybdenum foil sealing portion 16. If desired, a portion of the straight wire end 20 may be replaced with a coiled end segment (not shown) similar to the coiled segment 24. If desired, for example, US Pat. Nos. 4,272,698 and 4,95
As disclosed in US Pat. No. 9,586, one or more coiled filament segments 24 may be replaced with filament segments of substantially straight wire (not shown). Moreover, the coiled filament segments 24 need not all have the same diameter, pitch, and spacing between turns of each other. An essential feature of the present invention is the integral support shown as individual sections 26 to support the filaments within the filament chamber 13 of the bulb, preferably with the longitudinal axis of the filament being the longitudinal axis of the filament chamber of the bulb. That is consistent with. The distance between the turns of the support depends on the filament and bulb design.

1600 watts, 240 volts and 24
A heating bulb rated at 50 ° K was successfully formed according to the present invention as shown in FIG. This heating bulb has a filament similar to that shown in FIG.
It has an envelope made of quartz or fused silica having a diameter of 7 mm (including a pressure-sealed portion) and an outer diameter of 10 mm. The filament length is 405 mm. The filament is formed of 11.53 mil diameter tungsten filament wire and has 17 filament segments 24. Each filament segment is 20 mm long and has 32 turns or coils with a diameter of 69 mils, with a space between turns of 0.61 mm. Each of the 18 integral spiral supports 26 is 3 mm
Of 2.5 turns for each space, each turn having an outer diameter of 270 mils and adjoining the inner surface of the filament chamber 13 to support the filament 22. Initially, these bulbs were made with zero distance between each winding of the filament support, but this tightly coiled coil structure allowed the quartz inner wall of the bulb adjacent to the support to move during lamp operation. It turned black and became devitrified. By expanding the coil of the support 26, the heating density applied to the inner wall of the filament chamber by the support was reduced, and the phenomenon of blackening and devitrification of the quartz was substantially reduced. Also, the bulb contained krypton at pressures above 1500 torr and a small amount of hydrogen and bromine. During operation, the filament segment 24 had a color temperature of 2478 ° K and the support 26 had a color temperature of 2187 ° K. The temperature of the walls of the quartz envelope between the supports 26 is 405 ° C or 628 ° K.
And the temperature of the wall portion adjacent the support was 535 ° C or 808 ° K. These bulbs have been operating continuously for over 5000 hours.

FIG. 2 shows a single ended bulb 50, which is a typical incandescent or halogen incandescent bulb. The bulb has a glass envelope 52, which has a filament chamber 53 and a pressure seal 54 against a molybdenum foil seal 56. The foil closure 56 has one end attached to the outer lead wire 57 and the other end attached to the filament support wires 58 and 60. The filaments are supported by support wires 58 and 60, one of which passes through an integral filament support coil section 68. The filament comprises three coiled filament segments 6 separated by an integral support 68 which positions it within the elongated filament chamber 53.
4, 65 and 66, the longitudinal axis of the filament being coincident with the longitudinal axis of the chamber 53.

The filament used in the bulb of the invention shown in FIG. 1 above is a single unbroken (continuous) filament without the use of the mandrel conventionally required to make coiled tungsten filaments. Formed of tungsten wire. The filament of this invention is 48034 Southfield, Michigan
K. P. American Corporation (KP American
Made by using the ITAYA MCS E series tension spring coiler model number MCS-8E, which is available from Corporation). This machine is a computer-aided coil spring forming machine designed to make wire springs, but has also been found to be useful in forming the filaments of the present invention. To make a filament of the invention using such a machine, a wire of straightened tungsten filament is fed from a spool through a hard metal quill by a pair of grooved feed rolls. Upon exiting the quill, the wire strikes a slide or movable tool mounted on a tool holder that can be moved by a cam. The forming tool is a grooved metal wheel or roller mounted at an angle to the longitudinal axis of the filament wire exiting the quill. Upon exiting the quill, the filament wire hits the groove of the forming tool and is continuously forced to the desired coil size. As the coil is formed, the distance from the forming tool to the wire changes momentarily,
The size of the coil changes to form a coil or filaments with straight wire filament segments, or both, and the diameter also gradually or sharply increases when the filament segment replaces the segment of the support. As mentioned above, the support segment or support is usually coiled or ring-shaped,
It can be made into various other shapes by means of a spring coiler. Various other tools can be used simultaneously to change the pitch and the distance between the turns. Using a tungsten wire with a diameter of 11.5 mil, the above IT
When making the above filaments for a 1600 watt heating bulb on an AYA spring coiler machine, it has been found beneficial to heat the wire with air at 300 ° C between the shaping tool at the exit of the quill. In addition, ITAYA
A machine may be used to offset one or more or all longitudinal axes of the elongated filament segments from the center (as shown in U.S. Pat. No. 2,454,765) and to the center axis of the support, as desired. The filaments can also be formed so that they do not match. Thus, the longitudinal axis of the filament segment may be parallel to, but not coincident with, the longitudinal axis of the support.

The above-described examples of filaments of the invention and light bulbs using these filaments are merely illustrative and are not meant to be limiting. The filaments of the present invention can be used in other incandescent bulb embodiments of various constructions, as will be apparent to those skilled in the art. Further, such bulbs having the filaments of the present invention may be provided with a thin film interference coating or film on at least a portion of the bulb's envelope to selectively transmit various portions of the electromagnetic spectrum. Such films or coatings are well known to those of ordinary skill in the art and are formed of alternating layers of two different refractory metal oxides having different indices of refraction. Such a film can change the color of visible light emitted from a light bulb or reflect infrared rays back to the filament to convert at least a part thereof into visible light. Also,
The heat and visible light reflective coating can also be provided as an integral reflector. In a light bulb in which at least a portion of the electromagnetic radiation is reflected back into the filament, the longitudinal axis of the filament must be exactly in radial alignment with or coincident with the longitudinal axis of the filament chamber. This is achieved in a simple, accurate and economical way using the filaments of the invention.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a double-ended incandescent lamp using integrally supported filaments according to the present invention.

FIG. 2 is a front view showing a single-ended light bulb using the integrally supported filament of the present invention.

[Explanation of symbols]

 12 Envelope 13 Filament chamber 20 Wire part 22 Filament 24 Filament segment 26 Support part

Claims (27)

[Claims] 1. An elongated continuous wire filament having a plurality of filament segments and an integral support. 2. The filament of claim 1 having at least two filament segments and at least two integral supports. 3. The filament of claim 2 having at least 3 filament segments and at least 3 integral supports. 4. The filament according to claim 3, wherein the supporting portion has a diameter larger than a diameter of the filament segment. 5. The filament of claim 4, wherein at least a portion of the filament segment is a coil. 6. The filament of claim 5, wherein the longitudinal axis of at least a portion of the filament segment coincides with the longitudinal axis of the support. 7. An elongated continuous wire filament having a plurality of filament segments and an integral support, at least one of said filament segments being in the form of an uncoiled wire. 8. The filament of claim 7, wherein the plurality of filament segments are straight wire segments. 9. The filament of claim 7, wherein the filament segments are interconnected by the support. 10. A light transmissive envelope surrounding a continuous wire filament having a plurality of filament segments and a plurality of integral supports, at least a portion of each support adjacent an inner wall of the envelope. An incandescent light bulb supporting the filament within the envelope. 11. The light bulb of claim 10, wherein the filament is longitudinally disposed within the envelope. 12. A light bulb according to claim 11, wherein both the segment and the support are arranged along a common longitudinal axis. 13. The bulb of claim 11, wherein the common longitudinal axis is coincident with the longitudinal axis of the bulb envelope. 14. A plurality of filament segments having elongate coils of windings of approximately the same diameter,
An elongated continuous wire filament in which the filament segments are separated from each other by an integral support ring, the diameter of the integral support ring being substantially larger than the diameter of the filament segment. 15. A tungsten wire as claimed in claim 1.
4. The filament according to 4. 16. The filament of claim 15, wherein the support rings are arranged along a common longitudinal axis. 17. The filament of claim 16, wherein the filament segments are arranged along a common longitudinal axis. 18. The filament of claim 16 wherein both the support ring and the longitudinal axis of the filament segment are coincident. 19. An elongated light transmissive envelope, and an elongated continuous tungsten wire filament having a plurality of coiled filament segments and an integral support disposed longitudinally within and hermetically enclosed within the envelope. The support is in the form of a ring or coil having a diameter substantially larger than the diameter of the filament segment, the support outer surface being adjacent to the inner surface of the envelope, The incandescent light bulb that is supported inside. 20. The light bulb of claim 19, wherein the filament segment and the support have a longitudinal axis. 21. Both of the axes are coincident.
0 described light bulb. 22. The bulb of claim 21, wherein the envelope and the filament have a longitudinal axis, both axes being coincident. 23. The light bulb of claim 22, wherein at least a portion of the envelope is provided with a light interference coating. 24. The light bulb of claim 19, wherein the diameter changes abruptly between the filament segment and the support. 25. The light bulb of claim 23, wherein the diameter changes abruptly between the filament segment and the support. 26. The light bulb of claim 19, having a light and heat reflective coating on the envelope. 27. The light bulb of claim 24, having a light and heat reflective coating on the envelope.