Heater with PTC element an buss system
First Claim
1. An electrical heater comprising:
- first and second busses disposed on a substrate in electrically isolated relation, the first and second busses electrically coupled with generally parallel conducting element portions and having corresponding first and second voltage application portions;
a thermistor layer electrically interconnecting the generally parallel conducting element portions;
a summation of electrical paths along the first and second busses from the first and second voltage application portions thereof to adjacent portions along the generally parallel conducting element portions is substantially the same.
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Accused Products
Abstract
The heater is formed from a substrate layer, a feeder buss layer, a dielectric layer, a PTF (polymer thick film) conductor or main buss layer, a PTC (positive temperature coefficient) thermistor layer and an external laminated adhesive layer. All of the layers are substantially coextensive. The feeder buss layer, dielectric layer, main buss layer and PTC thermistor layers are preferably screen printed or otherwise selectively applied. The feeder buss layer includes first and second external electrical terminals formed on a single side thereof, and a buss for providing electrical communication from the first terminal to a connector diagonally removed from the second terminal. The connector and the second terminal provide electrical communication to diagonally opposed corners of the PTF conductor or main buss layer thereby providing relatively uniform current path distances through the thermistor layer.
57 Citations
16 Claims
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1. An electrical heater comprising:
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first and second busses disposed on a substrate in electrically isolated relation, the first and second busses electrically coupled with generally parallel conducting element portions and having corresponding first and second voltage application portions;
a thermistor layer electrically interconnecting the generally parallel conducting element portions;
a summation of electrical paths along the first and second busses from the first and second voltage application portions thereof to adjacent portions along the generally parallel conducting element portions is substantially the same. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An electrical heater comprising:
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a substrate;
first and second electrically isolated busses disposed on the substrate the first and second busses electrically coupled to generally parallel conducting element portions arranged in a generally rectangular pattern;
a first voltage terminal coupled to the first buss and a second voltage terminal coupled to the second buss, the first and second voltage terminals located diagonally opposite each other. - View Dependent Claims (8, 9, 10, 11)
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12. In an electrical heater comprising an insulating substrate having first and second conducting elements disposed thereon interconnected by a positive temperature coefficient material, the improvement comprising:
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the first and second conducting elements arranged substantially symmetrically in a generally rectangular pattern;
a first voltage terminal coupled to the first conducting element and a second voltage terminal coupled to the second conducting element, the first and second voltage terminals located in diagonally opposite corners of the generally rectangular pattern. - View Dependent Claims (13, 14, 15, 16)
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Specification