Film resistors having trimmable electrodes
First Claim
1. A resistor device comprising:
- an electrical insulating substrate;
a pair of separated electrically conductive electrodes on a surface of said substrate;
an electrical resistance film formed on said substrate surface between said separated electrodes and having a width-wide dimension such that regions of said substrate surface are interposed between said film and each of said electrodes; and
a plurality of electrically conductive fingers each having one end integral with one of said electrodes and a terminal end which is in electrical contact with said film, said fingers between said one and terminal ends thereof electrically bridging a respective one of said interposed substrate surface regions;
whereinat least one of said electrically conductive fingers is severed at a location coextensive with said respective one of said interposed substrate surface regions without disturbing said electrical resistance film to achieve a selected resistance value for said resistor device.
1 Assignment
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Accused Products
Abstract
Thin or thick film resistor devices (e.g., electronic resistors and thermistors) are trimmable without disturbing the active resistor film or necessarily requiring temperature control during trimming by providing a plurality of electrically conductive fingers having one end integral with one of the electrodes and a terminal end which extends at least substantially across the cross-wise dimension of the resistance film. The electrode fingers thereby electrically bridge a respective surface region of the substrate on which the electrodes and film are disposed. One or more of these fingers may thus be severed from the electrodes at the bridged respective surface region of the substrate so that the resistance value of the device can be controllably selected. By providing various finger-to-finger separation dimensions (to thereby establish various widths of segments of the active resistor film), a large number of resistance trimming combinations can be provided so that virtually any desired resistance value for the device can be obtained in dependence upon the particular finger(s) which is(are) severed. The resistance of very high resistance thermistors may also easily be reduced (e.g., by factors of 100 or more) to an extent where impedance loading measuring errors are minimized (if not eliminated entirely), or low TCR circuit resistors are varied in resistance as desired over a wide range without having to change the formulation of the resistor body material.
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Citations
24 Claims
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1. A resistor device comprising:
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an electrical insulating substrate; a pair of separated electrically conductive electrodes on a surface of said substrate; an electrical resistance film formed on said substrate surface between said separated electrodes and having a width-wide dimension such that regions of said substrate surface are interposed between said film and each of said electrodes; and a plurality of electrically conductive fingers each having one end integral with one of said electrodes and a terminal end which is in electrical contact with said film, said fingers between said one and terminal ends thereof electrically bridging a respective one of said interposed substrate surface regions;
whereinat least one of said electrically conductive fingers is severed at a location coextensive with said respective one of said interposed substrate surface regions without disturbing said electrical resistance film to achieve a selected resistance value for said resistor device. - View Dependent Claims (2, 3, 4, 6)
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5. A resistor device comprising:
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an electrical insulating substrate; a pair of separated electrically conductive electrodes on a surface of said substrate; an electrical resistance film formed on said substrate surface between said separated electrodes and having a width-wise dimension such that regions of said substrate surface are interposed between said film and each of said electrodes; and a plurality of electrically conductive fingers each having one end integral with one of said electrodes and a terminal end which is in electrical contact with said film, said fingers between said one and terminal ends thereof electrically bridging a respective one of said interposed substrate surface regions;
whereinsaid fingers of one of said electrodes are alternately disposed relative to said fingers of the other of said electrodes such that at least one pair of said alternately disposed fingers is separated by a first predetermined dimension which is different from a second predetermined dimension separating at least one other pair of said alternately disposed fingers so as to establish respective segments of said electrical resistance film having lengths corresponding to said first and second predetermined dimensions and thereby establish respectively different resistance values of said electrical resistance film upon severing of at least one of said alternately disposed fingers;
whereinsaid fingers are severable at a location coextensive with said respective one of said interposed substrate surface regions such that severing at least one finger of said one and other pairs of said alternately disposed fingers changes a resistance value of said resistor device to an extent corresponding to said respectively different resistance value of said electrical resistance film.
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7. A film resistor comprising:
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a substrate; an active resistor body disposed on said substrate; and electrodes disposed on said substrate laterally of said active resistor body such that respective regions of said substrate separate said electrodes from said active resistor body;
whereinsaid electrodes include several fingers which extend across said respective substrate regions into electrical communication with said active resistor body, said fingers being severable at a location coextensive with said respective substrate regions to disable electrical communication with said film resistor without disturbing said active resistor body and thereby obtain a desired resistance value thereof. - View Dependent Claims (8, 9, 10, 11, 12)
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13. In a trimmable film resistor comprising an insulating substrate, an active resistor body disposed on a surface of said substrate, and a pair of electrodes disposed on said surface of said substrate in electrical communication with said active resistor body, the improvement wherein:
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several elongate fingers extend from each one of the electrodes toward each other of the electrodes such that fingers of said each one of the electrodes are alternately disposed on said active resistor body relative to fingers of said other of the electrodes; and
whereinsurface regions of said substrate are interposed between said active resistor body and said electrodes such that said fingers of each one of said electrodes extend across a respective one of said surface regions; and
whereinat least one of said several elongate fingers is severed at a location coextensive with said respective one of said interposed surface regions to disable electrical communication of said at least one of said several elongate fingers with said active resistor body and obtain a desired resistance value thereof. - View Dependent Claims (14, 15)
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- 16. A method of trimming to a desired resistance value a film resistor having a substrate, an active resistor body disposed on a surface of said substrate, and a pair of electrodes disposed on said surface of said substrate laterally of said active resistor body so that a region of said substrate is established therebetween, each electrode having fingers which extend across a respective one of said substrate regions and are in electrical communication with said active resistor body, said method comprising severing one or more of said fingers at a location coextensive with said respective substrate region thereby obtaining the desired resistance value for the film resistor.
Specification