US3722085A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making film-type power resistors
Assignee: Individual
•
Filing: 1971-09-23
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Granted: 1973-03-27
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Expires: 1991-09-23
Abstract
Abstract A film-type power resistor consists of a ceramic wafer or washer having a central opening, one side of such washer being printed at its outer and inner edges with generally annular traces of termination metal. An electrically resistive film is printed on such one side over all portions of, and between, the termination metal, excepting for predetermined adjacent end portions which are connected to radially outwardly extending terminal lugs or leads. In one embodiment, the metal traces are continuous, whereas in another embodiment they are interrupted in order to create series-related resistor portions. The washer (and its associated films) are mounted over a metal base and are embedded in a thermosetting synthetic resin, the base having an upwardly extending central post which passes through the opening in the washer to the upper surface of the resin. In accordance with the method, the planar surface of a ceramic substrate is first printed with termination film traces, following which such traces are overprinted with electrically resistive film. The ceramic (with its associated coatings) is then fired in order to cure the resistive film. Thereafter, the entire outer surface of the resistive film is uniformly abraded by means of a jet of abrasive particles, the abrading continuing in a uniform manner until the resistive film is within the required tolerance. During the abrading step, the terminal regions of the terminal film traces are masked. Thereafter, terminal lugs or leads are connected to such terminal regions.
Inventors
- 👤 R Caddock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:07
CPC Classifications
H; H01; H01C; H01C17/00; H01C17/22; H01C17/24; H01C17/245; H01C10/00; H01C10/30; H01C10/305; H01C7/00; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49087; Y10T29/49099; Y10T29/49101
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
35 words
The invention as claimed in claim 1, in which said method further comprises performing said abrading step by directing against said resistive film, and in substantially perpendicular relationship relative thereto, a jet of abrasive material.
Claim 2
Dependent Claim
48 words
The invention as claimed in claim 1, in which said method further comprises performing said abrading step by directing a jet of abrasive material against said film, and scanning said jet and film relative to each other in a manner effecting uniform abrasion of substantially said entire film.
Claim 3
Dependent Claim
20 words
The invention as claimed in claim 3, in which said method further comprises directing said jet perpendicularly to said film.
Claim 4
Dependent Claim
52 words
The invention as claimed in claim 1, in which said method further comprises employing a ceramic as said substrate, employing metal films as said termination traces, employing a film of complex metal oxides in a glass matrix as said resistive film, and firing said resistive film after application thereof to said surface.
Claim 5
Dependent Claim
41 words
The invention as claimed in claim 1, in which said method further comprises the step of electrically connecting terminal conductors to said termination traces, and causing said terminal conductors to extend outwardly from said surface in a direction generally parallel thereto.
Claim 6
Dependent Claim
44 words
The invention as claimed in claim 1, in which said method further comprises overprinting said resistive film on at least major portions of said termination traces, whereby to protect said major portions of said traces from abrasion as the result of said abrading step.
Claim 7
Independent Claim
140 words
A method of manufacturing a power resistor, which comprises: providing a ceramic washer having a central opening and having planar upper and lower surfaces which are parallel to each other, adherently applying termination traces to said upper surface in the form of metal film regions located at at least a predetermined portion of the circumference of said washer, adherently applying a resistive film to said upper surface and in electrical contact with said traces, firing said washer and the films adhered thereto, directing a jet of abrasive material against a portion of said resistive film and uniformly scanning said jet and film relative to each other to effect uniform reduction in the thickness of said film throughout substaNtially all portions thereof, and continuing said abrading step until the electrical resistance of said film is within a predetermined range of values.
Claim 8
Dependent Claim
26 words
The invention as claimed in claim 8, in which said method further comprises directing said jet against said film in a direction perpendicular to said film.
Claim 9
Dependent Claim
87 words
The invention as claimed in claim 8, in which said method further comprises employing a ceramic washer having a circular peripheral edge which is concentric with a circular inner edge, the latter edge defining said central opening, employing as said jet a jet having a diameter, at said surface, substantially equal to the radial distance between said inner edge and said peripheral edge, and scanning said jet relative to said resistive film in uniform manner to effect uniform reduction in the thickness of said entire resistive film.
Claim 10
Dependent Claim
26 words
The invention as claimed in claim 10, in which said method further comprises directing said jet against said film in a direction perpendicular to said film.
Claim 11
Dependent Claim
53 words
The invention as claimed in claim 8, in which said method further comprises providing a mask over said predetermined portion of the circumference of said washer, and performing said abrading step by directing a jet of abrasive material against the upper surface of said washer at all portions thereof except at said mask.
Claim 12
Dependent Claim
69 words
The invention as claimed in claim 12, in which said method further comprises making electrical connections to said termination traces at the region beneath said mask, and effecting connection of said electrical connections to a resistance-measuring means whereby to determine when said abrading step has effected a sufficient reduction in the thickness of said resistive film to cause the resistance thereof to be within said predetermined range of values.
Claim 13
Dependent Claim
42 words
The invention as claimed in claim 8, in which said method further comprises connecting radially outwardly extending electrical conductors to said washer at said predetermined portion of the circumference thereof and in electrical contact with said termination traces at said predetermined portion.
Claim 14
Dependent Claim
34 words
The invention as claimed in claim 14, in which said connections are effected by means of rivets, and in which said conductors are caused to lie generally in the plane of said resistive film.
Claim 15
Dependent Claim
34 words
The invention as claimed in claim 8, in which said method further comprises employing as said washer a ceramic washer, and employing as said resistive film a complex metal oxide in a glass matrix.
Claim 16
Dependent Claim
45 words
The invention as claimed in claim 8, in which said method further comprises overprinting said resistive film on at least substantial portions of said termination traces, whereby to protect said termination traces against said jet of abrasive material and thus prevent abrading of said traces.
Claim 17
Dependent Claim
111 words
The invention as claimed in claim 8, in which said method further comprises causing said termination traces to include concentric inner and outer trace portions which extend, respectively, around the inner edge of said washer in encompassing relationship relative to said opening therein and around the outer edge of said washer, causing said trace portions to each have at least one end extending to said predetermined portion of the circumference of said washer, and providing said resistive film on said surface in electrical contact with said trace portions extending about said opening whereby to permit radial flow of current between said inner and outer trace portions and through said resistive film.
Claim 18
Dependent Claim
55 words
The invention as claimed in claim 18, in which said method further comprises effecting interruption of said resistive film and at least one of said trace portions at a region remote from said predetermined portion of the circumference of said washer, whereby to permit series flow of current through series-connected portions of said resistive film.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |