Variable watt density layered heater

• US 20050199610A1
• Filed: 03/10/2004
• Published: 09/15/2005
• Est. Priority Date: 03/10/2004
• Status: Active Grant

• Current Assignee: Watlow Electric Manufacturing Company
• Original Assignee: Watlow Electric Manufacturing Company
• Inventors: McMillin, James, Ptasienski, Kevin, Nagl, Thomas T., Juliano, Rolando O.
• Granted Patent: US 7,132,628 B2
• Time in Patent Office: Days
• 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 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.

Claims

1. A layered heater comprising:

at least one resistive layer comprising 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.

2. The layered heater according to claim 1, wherein the resistive circuit pattern further comprises a spacing that is constant.

3. The layered heater according to claim 1, wherein the resistive circuit pattern further comprises a spacing that 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:

at least one resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a width,

wherein a thickness of the resistive circuit pattern varies across the width of the resistive circuit pattern for a variable watt density.

11. A layered heater comprising:

at least one resistive layer comprising a resistive circuit pattern, the resistive circuit pattern comprising a material having a variable composition,

wherein the resistive circuit pattern comprises a variable watt density.

12. A layered heater comprising:

at least one resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a length, a width, and a thickness,

wherein the width and the thickness vary along the length of the resistive circuit pattern for a variable watt density.

13. A layered heater comprising:

at least one resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a length, a width, a spacing, and a thickness,

wherein the width, spacing, and thickness vary along the length of the resistive circuit pattern for a variable watt density.

14. A layered heater comprising:

at least one resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a length, a spacing, and a thickness,

wherein the spacing and the thickness vary along the length of the resistive circuit pattern for a variable watt density.

15. 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 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 resistive circuit pattern for a variable watt density.

16. 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 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 circuit pattern for a variable watt density.

17. A resistive circuit pattern for use in a layered heater, the resistive circuit pattern defining a variable thickness.

18. A layered heater comprising:

at least one resistive layer comprising a resistive circuit pattern, the resistive circuit defining a variable thickness.

19. The layered heater according to claim 18 further comprising a plurality of resistive layers.

20. A method of forming a resistive circuit pattern of a layered heater, the method comprising the steps of:

(a) dispensing a conductive ink at a rate onto a surface; and

(b) varying the dispensing rate of the conductive ink to form a variable thickness resistive circuit pattern.

21. A method of forming a resistive circuit pattern of a layered heater, the method comprising the steps of:

(a) dispensing a conductive ink at a rate onto a surface; and

(b) varying a feed speed of the substrate relative to the dispensing of conductive ink to form a variable thickness resistive circuit pattern.

22. A method of forming a resistive circuit pattern of a layered heater, the method comprising the steps of:

(a) dispensing a conductive ink at a rate onto a surface;

(b) varying the dispensing rate of the conductive ink; and

(c) varying a feed speed of the substrate relative to the dispensing of conductive ink,

wherein a variable thickness resistive circuit pattern is produced.

23. A method of forming a resistive circuit pattern of a layered heater, the method comprising the steps of:

(a) applying a volume of conductive ink onto a surface to form a trace; and

(b) applying an additional volume of conductive ink onto the trace,

wherein a variable thickness resistive circuit pattern is produced.

24. The method according to claim 23, wherein the volumes of conductive ink are applied by a layered process selected from the group consisting of thick film, thin film, thermal spraying, and sol-gel.

25. The method according to claim 23, wherein the volumes of conductive ink are applied using precision pen writing equipment.

26. The method according to claim 23, wherein the volumes of conductive ink are applied using a silk screening process.

27. A layered heater comprising a means for varying the watt density of a resistive circuit pattern.