US2818354A - Electrical resistor and method of making same - Google Patents

Electrical resistor and method of making same Download PDF

Info

Publication number
US2818354A
US2818354A US475938A US47593854A US2818354A US 2818354 A US2818354 A US 2818354A US 475938 A US475938 A US 475938A US 47593854 A US47593854 A US 47593854A US 2818354 A US2818354 A US 2818354A
Authority
US
United States
Prior art keywords
iridized
coating
glass
frit
resistor
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
Application number
US475938A
Other languages
English (en)
Inventor
Pritikin Nathan
Robert C Camp
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PRITIKIN
Original Assignee
PRITIKIN
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by PRITIKIN filed Critical PRITIKIN
Priority to US475938A priority Critical patent/US2818354A/en
Priority to CH355201D priority patent/CH355201A/de
Priority to GB34818/55A priority patent/GB794848A/en
Priority to BE543680D priority patent/BE543680A/xx
Application granted granted Critical
Publication of US2818354A publication Critical patent/US2818354A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
    • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
    • H05B3/26—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor mounted on insulating base
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/006—Thin film resistors

Definitions

  • This invention relates to an electric resistor and to a method of making such a resistor. It is an object of this invention to provide an improved resistor and an improved method of making the same.
  • iridized coatings of various metal oxides have been employed in the past for resistors, particularly transparent heating elements. These have been successfully employed in Windshields, the heat obtainable by passing a current through the transparent coating being employed to keep the windshield free of ice. They have also been employed successfully in space-heating elements, a relatively large sheet of glass having any desired pattern of metal oxide deposited thereon. In applications such as these, slight variations in the resistance of the iridized coatingsis not objectionable since the objective is a reasonable amount of heat distributed with reasonable uniformity over the surface of the glass, or other base, to which the iridized coating adheres.
  • iridized coatings to resistors of the type commonly employed in electronic apparatus has been limited because of a lack of suitable means for protecting the iridized coating from the atmosphere. Because of the fact that iridized coatings have certain very advantageous characteristics as applied to resistors of the type commonly employed in electronic apparatus, namely, small temperature coefficient of resistance, and stability (when not subjected to the atmosphere), various attempts have been made to find a suitable protective coating for iridized coatings. All of these attempts have been unsuccessful because the protective coatings applied to the iridized coating either were subject to rapid decomposition (especially under severe conditions of temperature and humidity) or permitted the passage therethrough of small amounts of moisture and oxygen.
  • the present invention contemplates the application of a protective inorganic film fused to the iridized coating. While the invention is particularly applicable to resistors of the type commonly employed in electronic apparatus it has application to other uses of iridized films and is to be given this broader interpretation except where it is otherwise specified.
  • Figure 1 is a plan view of a resistor of the type commonly employed in electronic apparatus, in one stage of production;
  • Fig. 2 is an enlarged elevational view of one portion of the partially completed resistor of Fig. 1;
  • Figs. 3 and 4 are views similar to Fig. 2, but showing the resistor in successively more complete stages of production;
  • Fig. 5 is an elevational view of the resistor element of Pig. 4 in a complete resistor construction
  • Fig. 6 is a view similar to Fig. 3, but showing an alternate construction.
  • the invention is shown applied to an electrical resistor of the type commonly employed in electronic apparatus.
  • the invention is particularly applicable to this type of resistor since this type is frequently required to have certain operating characteristics which can be obtained only if the resistance film is well protected from the atmosphere.
  • the invention has application to other types of resistors (including heating resistors of various types) since in most cases it is desirable that the resistance film be protected from outside influences, both atmospheric and mechanical.
  • the resistance element shown in Figs. 1 and 2 includes a glass sheet 10 having spaced apart terminals 11 secured to one face thereof. Also adhering to the same surface of the glass sheet 10 is an iridized coating 12. In Fig. 3 a thin layer of glass frit 13 is shown applied to the exposed surface of the iridized coating 12, and in Fig. 4 the layer of glass frit is shown fused to form a continuous film 13a over the iridized coating.
  • Fig. 5 the glass sheet 10 with its adhering films and terminals is shown assembled with a second glass sheet 20, having terminals 21 adhering thereto opposite the terminals 11.
  • a lead 22 Arranged between the terminals at one end of the two glass sheets is a lead 22.
  • This lead is preferably soldered to the two terminals 21 in order to provide a strong over-all assembly.
  • the space between the two glass sheets 10 and 20, which is not occupied by the leads 22 and the adjacent solder is filled by a third glass sheet 23. It will be understood that a lead 22 is arranged at each end of the assembly.
  • Fig. 5 The general assembly of Fig. 5 is disclosed in detail and is claimed in application Serial No. 463,303 entitled, Electrical Component and Method of Making Same, filed October 19, 1954, by the same inventor. Since the particular assembly in which a resistor constructed in accordance with the present invention may be incorporated does not in itself constitute a part of the present invention, the assembly is not described in further detail herein.
  • the iridized coating 12 shown in Figs. 1 and 2 may be of tin oxide or of any of the various other metal oxides which form a suitable resistance film of high or low resistance per square.
  • Such metal oxide films are generally produced by mixing a salt of the desired metal in a liquid carrier and by spraying this on a heated glass sheet.
  • the resulting iridized coatings are generally accepted as being formed primarily of the metal oxide, although there is some difference of opinion as to the exact composition.
  • films of this type are referred to herein as iridized coatings of metal oxides.
  • iridized coatings of metallic oxides contain the, metal and oxygen elements in an arrangement which. does not constitute a true oxide of metal.
  • these coatings are partially metal oxides and partially metal in a pure state or in combination with-other elements. Accordingly, the expression iridized coating of metal oxides is intended to include thisgeneral type.ofxcoating regardless of whether the coatingis actually apropenmetal oxide, speaking in strict chemical terms.
  • the base 10 as shown .in the drawing, .is indicated above as .being of I glass. Itlmay be ,of ordinary window glass, theat-resistantglass such as Pyrex, ceramics, or-any other inorganic insulating material. .
  • the base should have a smooth, nonporous surface and should meet the physical requirements called for .by the application .of the ultimate resistor.
  • the base is, of course, the material actually contacting the iridized coating and might be, for example a glass film or other glaze on an underlying metallic foundation.
  • the glass frit 13, shown in Fig. 3, may be a conventional frit obtainable on the market. Where the resistor is to be subjected to substantial changes in temperature-it is recommended that the frit have a temperature coefficient of expansion nearly equal to or slightly less than that of the base 10. In general the frit must be fusible under applied heat which will not be detrimental to the iridized coating 12, the terminals 11 or the base 10. By employing rapid heating of the frit, it is possible to fuse the frit without damage to the other components, and particularly the base 10, even though the material of the base may have substantially the same melting temperature as the frit. The frit must melt to such an extent that the particles n the frit fuse together to form a continuous film.
  • Heat maybe applied rapidly and for only a short time, whereby only some portion of the frit melts or softens. Particularly the outer surfaces of the individual particles soften, whereas the inner core of each particle might remain substantially solid.
  • the only essential for complete protection of the iridized coating is that the frit be fused to form a continuous film, fused to the iridized coating.
  • differing materials may be incorporated in the frit, and all of the materials in the frit need not melt or fuse at the same temperature.
  • all that is essential for complete protection of the iridized coating is that a sufficient portion of the frit be melted or softened that a continuous film be formed and fused to the iridized coating.
  • the frit may have the characteristics of what is commonly termed a ceramic.
  • glass frit is intended to encompass any inorganic nonconducting frit of which a sufficient proportion will melt or soften at a reasonable temperature to cause the formation of a continuous film, fused to the iridized coating.
  • a continuous film refers to one in which adjacent particles of frit are melted or fused to a sufficient extent that the melted material bridges substantially continuously between adjacent particles wherever the frit is applied.
  • the over-all pattern of the frit as applied may be continuous or discontinuous in different applications.
  • the frit may be deposited on the iridized coating in any desired manner, but it has been found to bepractical to use a screening process.
  • the frit is mixed with a carrier such as 5% ethyl cellulose and pine oil.
  • the overall mixture may be 25 %'carrier and 75 frit or to the desired consistency.
  • the pine oil may be allowed'toevaporate or may be baked out. All elements-of thesuggested carrier are either evaporated or burned up when subsequently subjected to temperatures which fuse the frit.
  • the frit should be applied heavily enough to provide a fused film of the desired th1ckness,'itbeing understood that the fused film will-be considerably thinner than the applied frit.
  • a film of four mils thickness is recommended for applications where normal voltages are encountered.
  • the film can, however, be made much thinner or thicker' where desired.
  • theterminals 11 are shown applied'to the base 10 before the application'of the'iridized coating 12, since the terminals are'shown'to underlie the extremities of the iridized coatings.
  • the iridized coating 13 may be appliedfirst, followed by application of the terminals 11'. In this case, parts of the terminals 11' overlie the extremities of the iridized coating 13. There is believed to be little, if any, difference between these alternatives in so far as performance and ease of production are concerned.
  • the terminals and theiridized coating must be either applied in .thedesired'patterns or must be reduced to the desired patterns after application to the entire surface. Attention is directed to the fact that :some difficulty has been encountered informing the iridized coating on a silver terminal. Accordingly, if the terminals are to be applied first, as in Figs. 1-5, a metal more noble than silver is recommended. On the other hand, if the iridized film is applied first, as in Fig. 6, silver terminals have been found to make good contact therewith.
  • the baselt is composed of ordinary window .glass, and the iridized coating 12 is primarily tin oxide.
  • the iridized coating is etched away to provide areas for application of the terminals.
  • the latter comprise glass .frit and metallic silver and are fused to the glass base 10 and overlie the ends of the iridized coating. It has been found that satisfactory electrical connection is thereby made between the terminals and the iridized coating, and that leads 22 may be soldered to the terminals to provide a mechanically strong construction.
  • the glass frit for covering the iridized coating is a lead boro silicate glass containing 69% lead oxide, 9% boron oxide, and 22% silica.
  • the glass film 13a is produced by spraying.
  • the resistor element of Fig. 2 is subjected to a spray of molten glass, producing the resistor element of Fig. 4 directly.
  • Apparatus for spraying molten glass onto the resistor element of Fig. 2 may be substantially identical to that commonly employed for spraying molten metals. Attention is directed, however, to the fact that molten glass has a very corrosive reaction on any metal which is susceptible to the formation of oxides. More specifically, if the metal employed in the construction of the spraying apparatus is susceptible to the formation of oxide at the temperature of the molten glass, the molten glass effectively removes any such oxides whereupon the metal again is exposed to oxidation and subsequent removal of the oxide film. Constant subjections of such metals to molten glass quickly destroy the metal. Accordingly, any portion of the spraying apparatus which is subjected to the molten glass should be plated with platinum. A very thin film of platinum is generally recognized as being strongly resistant to corrosion by molten glass.
  • the resistor element of Fig. 2 is heated be-- fore being subjected to the spray of molten glass, and more particularly, is heated beyond the strain point of the base 10.
  • the base may be unheated.
  • a glass sheet may be substituted for the glass frit or the sprayed glass to seal the exposed surface of the iridized metal oxide coating.
  • a glass sheet is laid over the resistor element of Fig. 2 and is heated until it is quite soft. Pressure is preferably applied to bring the softened glass sheet into intimate contact with the iridized metal oxide coating at all points.
  • the glass sheet employed to seal the iridized metal oxide coating has a temperature coefficient expansion nearly equal to that of the base 10.
  • the glass sheet need not be clear glass but may incorporate materials which do not soften during its application to the iridized metal oxide coating, all as explained above in connection with use of glass frit.
  • the method of making an electrical resistor which comprises depositing an iridized coating of metal oxide on a preformed inorganic insulating base, and fusing a film of glass on the exposed surface of said iridized coating.
  • the method of making an electrical resistor which comprises depositing. an iridized coating of tin and antimony oxide on a preformed inorganic insulating base, and spraying molten glass on the surface of said iridized coating.
  • An electrical resistor comprising a preformed base of inorganic insulating material, an iridized tin oxide resistance film on said base,and a continuous, unitary glass film secured in'intimate molecular contact to the surface of said resistance film.
  • An electrical resistor comprising a preformed base of inorganic insulating material, an iridized tin and antimony oxide resistance film on said base, and a continuous, unitary glass film secured in intimate molecular contact to the surface of said resistancefilm.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Apparatuses And Processes For Manufacturing Resistors (AREA)
  • Surface Heating Bodies (AREA)
US475938A 1954-12-17 1954-12-17 Electrical resistor and method of making same Expired - Lifetime US2818354A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US475938A US2818354A (en) 1954-12-17 1954-12-17 Electrical resistor and method of making same
CH355201D CH355201A (de) 1954-12-17 1955-11-29 Verfahren zur Herstellung eines elektrischen Widerstandes
GB34818/55A GB794848A (en) 1954-12-17 1955-12-05 Electrical resistor and method of making same
BE543680D BE543680A (enrdf_load_stackoverflow) 1954-12-17 1955-12-15

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US475938A US2818354A (en) 1954-12-17 1954-12-17 Electrical resistor and method of making same

Publications (1)

Publication Number Publication Date
US2818354A true US2818354A (en) 1957-12-31

Family

ID=23889805

Family Applications (1)

Application Number Title Priority Date Filing Date
US475938A Expired - Lifetime US2818354A (en) 1954-12-17 1954-12-17 Electrical resistor and method of making same

Country Status (4)

Country Link
US (1) US2818354A (enrdf_load_stackoverflow)
BE (1) BE543680A (enrdf_load_stackoverflow)
CH (1) CH355201A (enrdf_load_stackoverflow)
GB (1) GB794848A (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920005A (en) * 1955-12-09 1960-01-05 Welwyn Electrical Lab Ltd Electrical resistors
US2927048A (en) * 1957-02-15 1960-03-01 Pritikin Nathan Method of making electrical resistors
US2934736A (en) * 1957-10-08 1960-04-26 Corning Glass Works Electrical resistor
US2957996A (en) * 1958-12-03 1960-10-25 Burroughs Corp Electron tube
US3088085A (en) * 1959-11-27 1963-04-30 Int Resistance Co Electrical resistor
US3170813A (en) * 1961-05-19 1965-02-23 Westinghouse Electric Corp Method for encapsulating semiconductors
US3200326A (en) * 1961-03-27 1965-08-10 Intellux Inc Resistance-capacitance device employing conductive and non conductive iridized oxidefilms
US3245830A (en) * 1962-04-30 1966-04-12 Owens Illinois Inc Glass furnace treatment
US3355308A (en) * 1963-06-24 1967-11-28 Projection transparency having a transparent powder image
US4146759A (en) * 1976-08-12 1979-03-27 Nissan Motor Company, Limited Ignition distributor

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2154387A (en) * 1938-05-24 1939-04-11 R Thomas & Sons Company Electric insulator
US2238031A (en) * 1938-06-10 1941-04-15 Joseph B Brennan Condenser and method of making same
US2289921A (en) * 1940-06-01 1942-07-14 Rca Corp Photosensitive electrode
US2489127A (en) * 1947-06-14 1949-11-22 Rca Corp High capacitance target
US2564707A (en) * 1947-09-03 1951-08-21 Corning Glass Works Electrically conducting coatings on glass and other ceramic bodies
USRE23556E (en) * 1952-09-30 Electrically conducting coating on
US2614944A (en) * 1947-07-22 1952-10-21 Pittsburgh Plate Glass Co Method of applying electroconductive films
US2648752A (en) * 1950-10-27 1953-08-11 Pittsburgh Plate Glass Co Transparent electroconductive article
US2648753A (en) * 1951-12-15 1953-08-11 Pittsburgh Plate Glass Co Transparent conducting films
US2717946A (en) * 1950-10-14 1955-09-13 Sprague Electric Co Electrical resistance elements

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE23556E (en) * 1952-09-30 Electrically conducting coating on
US2154387A (en) * 1938-05-24 1939-04-11 R Thomas & Sons Company Electric insulator
US2238031A (en) * 1938-06-10 1941-04-15 Joseph B Brennan Condenser and method of making same
US2289921A (en) * 1940-06-01 1942-07-14 Rca Corp Photosensitive electrode
US2489127A (en) * 1947-06-14 1949-11-22 Rca Corp High capacitance target
US2614944A (en) * 1947-07-22 1952-10-21 Pittsburgh Plate Glass Co Method of applying electroconductive films
US2564707A (en) * 1947-09-03 1951-08-21 Corning Glass Works Electrically conducting coatings on glass and other ceramic bodies
US2717946A (en) * 1950-10-14 1955-09-13 Sprague Electric Co Electrical resistance elements
US2648752A (en) * 1950-10-27 1953-08-11 Pittsburgh Plate Glass Co Transparent electroconductive article
US2648753A (en) * 1951-12-15 1953-08-11 Pittsburgh Plate Glass Co Transparent conducting films

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920005A (en) * 1955-12-09 1960-01-05 Welwyn Electrical Lab Ltd Electrical resistors
US2927048A (en) * 1957-02-15 1960-03-01 Pritikin Nathan Method of making electrical resistors
US2934736A (en) * 1957-10-08 1960-04-26 Corning Glass Works Electrical resistor
US2957996A (en) * 1958-12-03 1960-10-25 Burroughs Corp Electron tube
US3088085A (en) * 1959-11-27 1963-04-30 Int Resistance Co Electrical resistor
US3200326A (en) * 1961-03-27 1965-08-10 Intellux Inc Resistance-capacitance device employing conductive and non conductive iridized oxidefilms
US3170813A (en) * 1961-05-19 1965-02-23 Westinghouse Electric Corp Method for encapsulating semiconductors
US3245830A (en) * 1962-04-30 1966-04-12 Owens Illinois Inc Glass furnace treatment
US3355308A (en) * 1963-06-24 1967-11-28 Projection transparency having a transparent powder image
US4146759A (en) * 1976-08-12 1979-03-27 Nissan Motor Company, Limited Ignition distributor

Also Published As

Publication number Publication date
GB794848A (en) 1958-05-14
CH355201A (de) 1961-06-30
BE543680A (enrdf_load_stackoverflow) 1959-09-11

Similar Documents

Publication Publication Date Title
US3266661A (en) Method of applying electro-conductive coatings and resulting article
US3252831A (en) Electrical resistor and method of producing the same
US2934736A (en) Electrical resistor
US2950995A (en) Electrical resistance element
US3477055A (en) Thermistor construction
US2818354A (en) Electrical resistor and method of making same
US3075860A (en) Method of adhering metal to a glass base
US2927048A (en) Method of making electrical resistors
US3069294A (en) Electrical metal oxide resistor having a glass enamel coating
US3370262A (en) Electrical resistor
GB1474095A (en) Resistors
US4087778A (en) Termination for electrical resistor and method of making the same
US3895218A (en) Electric heater plate and terminal thereof
US3206702A (en) Electrical resistance element
US2786925A (en) Metal film resistor
US3307134A (en) Encapsulated impedance element
US3380156A (en) Method of fabricating thin film resistors
US2915730A (en) Electrical resistor and method
US4397915A (en) Electrical resistor material, resistor made therefrom and method of making the same
US4322477A (en) Electrical resistor material, resistor made therefrom and method of making the same
US3337365A (en) Electrical resistance composition and method of using the same to form a resistor
US4378409A (en) Electrical resistor material, resistor made therefrom and method of making the same
US4689271A (en) Coating for metallic substrates
US4139832A (en) Glass-coated thick film resistor
US5169465A (en) Thick-film circuit element on a ceramic substrate