Variable watt density layered heater

• US 8,901,464 B2
• Filed: 11/12/2012
• Issued: 12/02/2014
• Est. Priority Date: 03/10/2004
• Status: Active Grant

• Current Assignee: Watlow Electric Manufacturing Company
• Original Assignee: Watlow Electric Manufacturing Company
• Inventors: Ptasienski, Kevin, McMillin, James, Nagl, Thomas T., Juliano, Rolando O.
• Primary Examiner(s): PELHAM, JOSEPH MOORE
• Application Number:
  US13/674,828
• Publication Number:
  US 20130068754A1
• Time in Patent Office: 750 Days
• Field of Search: None
• US Class Current: 219/543
• CPC Class Codes: H05B 2203/003 using serpentine layout
• CPC Class Codes: H05B 2203/013 Heaters using resistive films or coatings
• CPC Class Codes: H05B 2203/017 Manufacturing methods or apparatus for heaters
• CPC Class Codes: H05B 2203/037 Heaters with zones of different power density
• CPC Class Codes: H05B 3/20 Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater H05B3/62, H05B3/68, H05B3/78, H05B3/84 take precedence
• CPC Class Codes: H05B 3/26 heating conductor mounted on insulating base for transparent areas H05B3/84, H05B3/86
• CPC Class Codes: H05B 3/28 heating conductor embedded in insulating material
• CPC Class Codes: H05K 1/0263 High current adaptations, e.g. printed high current conductors or using auxiliary non-printed means; Fine and coarse circuit patterns on one circuit board H05K1/0293 takes precedence
• CPC Class Codes: H05K 1/0265 characterized by the lay-out of or details of the printed conductors, e.g. reinforced conductors, redundant conductors, conductors having different cross-sections
• CPC Class Codes: H05K 1/167 incorporating printed resistors
• CPC Class Codes: H05K 2201/09736 Varying thickness of a single conductor; Conductors in the same plane having different thicknesses
• CPC Class Codes: H05K 2203/0126 Dispenser, e.g. for solder paste, for supplying conductive paste for screen printing or for filling holes
• CPC Class Codes: H05K 3/1241 by ink-jet printing or drawing by dispensing
• CPC Class Codes: Y10T 29/49099 Coating resistive material on a base

Abstract

A layered heater is provided that includes at least one resistive layer having a resistive circuit pattern, the resistive circuit pattern defining a length, a width, and a thickness, wherein the thickness varies along the length of the resistive circuit pattern and/or the width of the resistive circuit pattern for a variable watt density. The present disclosure 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.

Claims

1. A layered heater comprising:

a substrate;

a resistive layer formed on the substrate, 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 each of the resistive layer and the protective layer are formed by a layered process selected from the group consisting of thick film, thin film, thermal spraying, and sol gel, and the thickness of the resistive circuit pattern varies along the length of the trace of the resistive circuit pattern to generate a variable watt density along the length of the trace of the resistive circuit pattern,

wherein the resistive circuit pattern includes a curved portion and an inner portion of the curve portion is thicker than an outer portion of the curved portion.

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 resistive circuit pattern is selected from a group consisting of series, parallel, and series-parallel.

7. The layered heater according to claim 1, wherein the variable thickness is continuous.

8. The layered heater according to claim 1, wherein the variable thickness is non-continuous.

9. A layered heater comprising:

a resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a plurality of traces having a length, a thickness, and a spacing;

terminal pads in contact with the resistive layer adapted to connect the resistive layer to a power source; and

a protective layer formed on the resistive layer,

wherein each of the resistive layer and the protective layer are formed by a layered process selected from the group consisting of thick film, thin film, thermal spraying, and sol gel, and the thickness of the traces of the resistive circuit pattern varies along the length of the traces of the resistive circuit pattern and the thickness of the traces of the resistive circuit pattern is determined based on a circuit configuration and a heat loss to generate a variable watt density along the length of the traces of the resistive circuit pattern,

wherein the resistive circuit pattern includes a curved portion and an inner portion of the curve portion is thicker than an outer portion of the curved portion.

10. The layered heater according to claim 9, wherein the spacing is constant.

11. The layered heater according to claim 9, wherein the spacing is variable.

12. The layered heater according to claim 9, wherein the resistive circuit pattern further comprises a width that is constant.

13. The layered heater according to claim 9, wherein the resistive circuit pattern further comprises a width that is variable.

14. The layered heater according to claim 9, wherein the resistive circuit pattern is selected from a group consisting of series, parallel, and series-parallel.

15. The layered heater according to claim 9, wherein the variable thickness is continuous.

16. The layered heater according to claim 9, wherein the variable thickness is non-continuous.

17. The layered heater according to claim 9, wherein the resistive circuit pattern comprises a material having a variable composition.

18. A layered heater comprising:

a resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a trace having a length, a width, a thickness, and a spacing;

terminal pads in contact with the resistive layer adapted to connect the resistive layer to a power source; and

a protective layer formed on the resistive layer,

wherein each of the resistive layer and the protective layer are formed by a layered process selected from the group consisting of thick film, thin film, thermal spraying, and sol gel, and the thickness of the resistive circuit pattern varies across the width of the trace of the resistive circuit pattern to generate a variable watt density across the width of the trace,

wherein the resistive circuit pattern includes a curved portion and an inner portion of the curve portion is thicker than an outer portion of the curved portion.

19. The layered heater according to claim 18, wherein the thickness of the resistive circuit varies along the length of the resistive circuit pattern.