US3631593A - Assembly of filamentary display devices - Google Patents

Assembly of filamentary display devices Download PDF

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Publication number
US3631593A
US3631593A US102A US3631593DA US3631593A US 3631593 A US3631593 A US 3631593A US 102 A US102 A US 102A US 3631593D A US3631593D A US 3631593DA US 3631593 A US3631593 A US 3631593A
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United States
Prior art keywords
filament
terminals
leg
legs
bonding
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 - Lifetime
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US102A
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English (en)
Inventor
Norman Lee Lindburg
Hamilton David Woodland
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RCA Corp
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RCA Corp
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Filing date
Publication date
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Publication of US3631593A publication Critical patent/US3631593A/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K7/00—Lamps for purposes other than general lighting
    • H01K7/04—Lamps for purposes other than general lighting for indicating
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K3/00—Apparatus or processes adapted to the manufacture, installing, removal, or maintenance of incandescent lamps or parts thereof
    • H01K3/06—Attaching of incandescent bodies to mount
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49082—Resistor making
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4981—Utilizing transitory attached element or associated separate material

Definitions

  • a refractory wire is wound in an elongated helix around and along a mandrel of a material different from that of the wire. A length of the wound mandrel is extended across and the helix thereof is bonded to spaced-apart legs of a fixture, and the mandrel is etched from within the helix.
  • the helix is mounted between two spaced-apart terminals by disposing one leg of the fixture adjacent to one of the terminals, bonding the helix to the terminal, severing the helix from the one fixture leg, disposing the other leg of the fixture adjacent to the other terminal, bonding the helix to the other terminal, and severing the helix from the other fixture leg.
  • This invention relates to filamentary-type display devices, and particularly to the process of fabricating and mounting the filaments of such devices.
  • One type of display device comprises an array of electrical resistance filaments individually mounted between pairs of support terminals. By passing an electrical current through various selected ones of the filaments, to heat the filaments to incandescence, various images, e.g., numerals, are displayed.
  • the various filaments are made of extremely small diameter wire, e.g., 0.0004 inch.
  • the filaments generally comprise coils of wire, the outer diameter of the coils being extremely small, e.g., 0.002 inch.
  • a problem associated with such small and thus fragile filaments is that of handling the filaments without damaging them. Further, an especially difficult problem is that of mounting the filaments between the terminals in an accurate and reproducible manner without excessive loss of product.
  • FIG. 1 is a schematic illustration of a portion of a display device, showing a substrate, the support terminals on the substrate, and an array of filaments mounted between pairs of the support terminals;
  • FIG. 2 shows, on an enlarged scale, a workpiece used in accordance with the instant invention
  • FIG. 3 shows a further workpiece, incorporating a portion of the workpiece shown in FIG. 2, used in accordance with the instant invention
  • FIG. 4 shows one step of the use of the workpiece shown in FIG. 3;
  • FIGS. 5 and 6 show subsequent steps in the use of the workpiece shown in FIG. 3.
  • a plurality of filamentary coils 10 are mounted between pairs of support and terminal posts 12 and 14, the posts being mounted on a substrate 15.
  • two of the posts 14 are each common to two different filaments 10.
  • Means are provided for connecting the posts 12 and 14 to terminal leads of the device, whereby electrical voltages can be applied between individual pairs of posts 12 and 14 to heat the filaments mounted between the post pairs to incandescence.
  • various images e.g., the numerals 0 through 9, in the illustrative embodiment, can be displayed.
  • Each filamentary coil 10 is formed of a given length of a refractory wire, e.g., tungsten with such additives as rhenium or thorium. When heated to incandescence, the length of the wire increases. To help prevent sag of the heated coils, the coils are preferably mounted under tension. According to one technique, the coils are fabricated with a length less than the distance between the posts between which the coils are to be mounted, and the coils are stretched and tensioned in the mounting operation.
  • the individual filamentary coils 10 are provided and mounted on the support posts as follows:
  • a wound mandrel assembly 16 (FIG. 2) is first formed by winding a refractory wire 18 around and along a mandrel 20 of a material different from the material of the wire 18.
  • the mandrel 20 may be molybdenum.
  • Means for winding fine wires around and along fine mandrels are known.
  • the wire 18 has a diameter of 0.4 mil, and is wound at 1,400 turns to the inch.
  • the molybdenum mandrel 20 has a diameter of 1.2 mils, the coil assembly 16 having an outer diameter of 0.002 inch.
  • the mandrel assembly 16 from which individual coils 10 are to be provided, as described hereinafter, is significantly stronger and more rigid than an unsupported filamentary coil 10, and is relatively easy to handle with little likelihood of damage thereto.
  • a length of the mandrel assembly 16 is then extended between two legs 26 and 28 (FIG. 3) of a U-shaped, flat metal frame 30, bonded to the legs 26 and 28, as by welding, and cut from the remainder of the assembly 16 to provide a frame assembly 32, as shown.
  • both the mandrel 20 and the wire 18 wound thereabout are individually bonded to the frame 30. This is necessary because the mandrel 20 will eventually be removed from within the coiled filament 18.
  • Two dimensions of the frame assembly 32 are specifically noted.
  • One dimension is the distance A between the inside edges of the frame legs 26 and 28. This dimension determines the amount of stretching of the filament coil 10 when the coil is mounted between a pair of support posts, as described hereinafter.
  • the other dimension is the distance B between the free ends 34 of the legs 26 and 28 and the point on the legs where the mandrel assembly 16 is bonded. This dimension determines the spacing between the filament coil 10 and the substrate 15 (FIG. I), as described hereinafter.
  • the frame 30 can be provided, for example, by a stamping process, whereby frames 30 of good dimensional accuracy can be readily and inexpensively provided.
  • the mandrel assembly I6 being relatively rigid, as noted, can be easily and accurately positioned on the frame 30, using, for example, a simple jig, not shown, whereby frame assemblies 32 can be accurately, simply, and inexpensively fabricated.
  • the mandrel 20 of the frame assembly 32 is selectively etched from within the wire 18 coiled thereabout. It is for this reason that the wire 18 and mandrel 20 should be of different materials.
  • an etchant of sulfuric and nitric acids can be used which attacks molybdenum at a much faster rate than it does tungsten.
  • the assembly is removed from the etchant before significant etching of the tungsten occurs.
  • the frame 30, having further use, described hereinafter, is made of a material resistant to the etchant used.
  • the frame can comprise stainless steel or an alloy of chromium and nickel, having the trade name Nichrome.
  • the mandrel can comprise a low melting temperature material, e.g., plastic, and the mandrel removing step comprises heating and melting away the mandrel. Chemical dissolution can also be used to remove such a mandrel.
  • a coil 10 is left suspended between the legs 26 and 28 of the frame 30.
  • the frame assembly 32 is next utilized to mount the filamentary coil 10 between two support posts 12 and 14. As shown in FIG. 4, this is accomplished by first disposing one leg 26 of the frame assembly 32 against the outer side of the post I2 (outer with respect to the other post 14), with the filamentary coil 10 extending across the post 12. Also, as shown, the free ends 34 of the frame legs 26 and 28 are disposed in engagement with the surface 40 of the substrate 15.
  • the portion of the coil I0 extending across the post 12 is then bonded to the post, as by welding or staking, or both.
  • the portion of the coil between the post 12 and the frame leg 26 is broken. Owing to the fineness of the coil wire 18, the separation of the coil from the frame leg 26 can be done simply by moving the frame 30 slightly away from the post 12.
  • the inside distance between the frame legs 26 and 28 is preferably somewhat less than the distance between the terminal posts 12 and 14. in this embodiment, for example, the distance between the posts 12 and M is 275 mils, and the inside distance between the frame legs 26 and 28 is 170 mils.
  • the frame assembly 32 is then moved to dispose (as shown in FIG. 5) the frame leg 28 against the outer side of the post 14 with the coil extending across the post 14.
  • the movement of the frame assembly 32 t0 the post 14 causes stretching and tensioning of the filamentary coil 10.
  • the portion of the coil 10 extending across the post 14 is then bonded, at the proper height, to the post 14, and the portion of the coil 10 between the post 14 and the frame leg 28 is broken by moving the frame away, as shown in FIG. 6. This completes the coil mounting operation.
  • the amount of stretching ofthe coil 10 is determined by the difference in spacings between the posts 12 and 14 and between the frame legs 26 and 28. While not described herein, the fabrication of substrates 15 having posts 12 and M in accurately spaced relationship is well known.
  • said step of securing said filament to said holding means includes disposing said mandrel assembly at a predetermined distance from ends of said legs, and
  • each of said terminal bonding steps includes the step of disposing said leg ends in engagement with a substrate on which said terminals are mounted.
  • a method of mounting a helical filament between a pair of spaced support terminals comprising:
  • said filament-fixture bonding step includes bonding said filament at a predetermined distance from ends of said legs, and
  • said filament-terminal bonding steps each includes the step of disposing said leg ends in engagement with a substrate on which said terminals are mounted.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Details Of Resistors (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Wire Processing (AREA)
US102A 1970-01-02 1970-01-02 Assembly of filamentary display devices Expired - Lifetime US3631593A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US10270A 1970-01-02 1970-01-02

Publications (1)

Publication Number Publication Date
US3631593A true US3631593A (en) 1972-01-04

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Application Number Title Priority Date Filing Date
US102A Expired - Lifetime US3631593A (en) 1970-01-02 1970-01-02 Assembly of filamentary display devices

Country Status (7)

Country Link
US (1) US3631593A (enExample)
CA (1) CA931207A (enExample)
DE (1) DE2100118A1 (enExample)
FR (1) FR2075160A5 (enExample)
GB (1) GB1326806A (enExample)
NL (1) NL7019072A (enExample)
SE (1) SE360778B (enExample)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1650605A (en) * 1926-12-09 1927-11-29 Gen Electric Filament for incandescent lamps or similar articles
US2145911A (en) * 1936-01-31 1939-02-07 Westinghousse Electric And Mfg Method of mounting coiled-coil filmaents
US2359302A (en) * 1942-06-11 1944-10-03 Tung Sol Lamp Works Inc Incandescent lamp and method of manufacture
US2454318A (en) * 1943-04-24 1948-11-23 Westinghouse Electric Corp Method of fabricating electron discharge devices
US2908842A (en) * 1957-02-25 1959-10-13 Telefunken Gmbh Filament tensioning

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1650605A (en) * 1926-12-09 1927-11-29 Gen Electric Filament for incandescent lamps or similar articles
US2145911A (en) * 1936-01-31 1939-02-07 Westinghousse Electric And Mfg Method of mounting coiled-coil filmaents
US2359302A (en) * 1942-06-11 1944-10-03 Tung Sol Lamp Works Inc Incandescent lamp and method of manufacture
US2454318A (en) * 1943-04-24 1948-11-23 Westinghouse Electric Corp Method of fabricating electron discharge devices
US2908842A (en) * 1957-02-25 1959-10-13 Telefunken Gmbh Filament tensioning

Also Published As

Publication number Publication date
CA931207A (en) 1973-07-31
DE2100118A1 (de) 1971-07-15
GB1326806A (en) 1973-08-15
NL7019072A (enExample) 1971-07-06
SE360778B (enExample) 1973-10-01
FR2075160A5 (enExample) 1971-10-08

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