Thick film resistor element with coarse and fine adjustment provision

DETAILED DESCRIPTION It is an object of the present invention to provide a thick film resistance element especially suited for use with hybrid circuits and which overcomes the foregoing deficiencies.
A more particular object of the present invention is to provide a thick film resistance element of the foregoing type which includes a coarse as well as a fine tune adjustment without materially affecting the speed of the laser beam cut.
Still another object of the present invention is to provide a thick film resistance element of the foregoing type which includes coarse and fine adjustment capabilities represented by separate resistive inks which produce different rates of resistive changes for a given length of laser cut.
In practicing the invention, a flat, ribbon-like sheet of resistance ink or paste is provided between associated terminals or conductors included on the surface of a ceramic substrate of an associated hybrid circuit.
The resistance element includes first and second portions or segments.
One such segment has a high resistance value per unit area, say for example, 300K ohm/unit area, while the second segment has a somewhat lower value, say for example, 100K ohms per unit area.
The first segment accomodates a laser cut which brings the resistance element to within a certain range below the desired value and thereby serves as a coarse adjustment.
The second portion or segment then accomodates a like laser cut, but because of the lower rate of change for the resistance per unit area, serves to provide a fine tune adjustment capability.