Variable watt density layered heater
View Patent ↗A layered heater is provided with a resistive layer having a resistive circuit pattern, the resistive circuit pattern defining a length and a thickness, wherein the thickness varies along the length of the resistive circuit pattern for a variable watt density. The present invention also provides layered heaters having a resistive circuit pattern with a variable thickness along with a variable width and/or spacing of the resistive circuit pattern in order to produce a variable watt density. Methods are also provided wherein the variable thickness is achieved by varying a dispensing rate of a conductive ink used to form the resistive circuit pattern, varying the feed rate of a target surface relative to the dispensing of the ink, and overwriting a volume of conductive ink on top of a previously formed trace of the resistive circuit pattern.
1. A layered heater comprising:
a dielectric layer;
a resistive layer formed on the dielectric layer, the resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a trace having a length, a thickness, and a spacing; and
a protective layer formed on the resistive layer,
wherein the thickness of the resistive circuit pattern varies along the length of the trace of the resistive circuit pattern for a variable watt density.
2. The layered heater according to claim 1 , wherein the spacing is constant.
3. The layered heater according to claim 1 , wherein the spacing is variable.
4. The layered heater according to claim 1 , wherein the resistive circuit pattern further comprises a width that is constant.
5. The layered heater according to claim 1 , wherein the resistive circuit pattern further comprises a width that is variable.
6. The layered heater according to claim 1 , wherein the layered heater is selected from a group consisting of thick film, thin film, thermal spray, and sol-gel.
7. The layered heater according to claim 1 , wherein the resistive circuit pattern is selected from a group consisting of series, parallel, and series-parallel.
8. The layered heater according to claim 1 , wherein the variable thickness is continuous.
9. The layered heater according to claim 1 , wherein the variable thickness is non-continuous.
10. A layered heater comprising:
a dielectric layer:
at least one resistive layer formed on the dielectric layer, the resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a trace having a width and a spacing; and
a protective layer formed on the at least one resistive layer,
wherein a thickness of the resistive circuit pattern varies across the width of the trace of the resistive circuit pattern for a variable watt density.
11. A layered heater comprising:
a substrate;
a dielectric layer formed on the substrate;
a resistive layer formed on the dielectric layer, the resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a trace having a length and a thickness; and
a protective layer formed on the resistive layer,
wherein the thickness of the resistive circuit pattern varies along the length of the trace of the resistive circuit pattern for a variable watt density.