Flexible heater device

• US 7,285,748 B2
• Filed: 12/21/2004
• Issued: 10/23/2007
• Est. Priority Date: 01/25/1999
• Status: Expired due to Fees

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Storiz, Paul J., Varma, Tilak R., Bulgajewski, Edward, Starozhitsky, Michael, Nelson, James P.
• Primary Examiner(s): Hoang; Tu Ba
• Assistant Examiner(s): Patel; Vinod
• Application Number:
  US11/018,977
• Publication Number:
  US 20050103775A1
• Time in Patent Office: 1,036 Days
• Field of Search: 219/217, 219/212, 219/219, 219/528, 219/529, 219/543, 219/549, 338/306
• US Class Current: 219/217
• CPC Class Codes: B60N 2/5685 Resistance
• CPC Class Codes: H05B 2203/006 using interdigitated electrodes
• CPC Class Codes: H05B 2203/011 Heaters using laterally extending conductive material as connecting means
• 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 2203/019 Heaters using heating elements having a negative temperature coefficient
• CPC Class Codes: H05B 2203/02 Heaters using heating elements having a positive temperature coefficient
• CPC Class Codes: H05B 2203/029 Heaters specially adapted for seat warmers
• CPC Class Codes: H05B 3/34 flexible, e.g. heating nets or webs
• CPC Class Codes: H05B 3/342 heaters used in textiles
• CPC Class Codes: H05B 3/347 woven fabrics

Abstract

The heating device includes a conductive layer which is positioned on an electrically insulative substrate. Preferably, the conductive layer is screen printed onto the substrate. The substrate is designed to limit elongation of the conductive layer, thereby improving the durability of the conductor and enabling the heating device to be used in flexible applications, such as automobile seats. The substrate can include at least one aperture passing therethough to further improve flexibility, fatigue resistance, and breathability of the heater. The conductive layer is configured to include a buss structure with a first buss ground inwardly adjacent from the periphery of the heating device and a first buss with serpentine paths extending from one edge of the heating device to another edge. The buss structure further includes a second buss with L-shaped portions positioned between the serpentine paths and the first buss ground. The second buss ground is located in a central location between the serpentine paths. A resistive or thermistor layer, preferably with a resistance which increases materially in response to increased temperature, is placed over the conductive layer.

Claims

1. A flexible seat heater for a vehicle, said heater comprising:

a substrate having at least one open space extending therethrough;

a polymeric layer of material applied to said substrate, wherein said substrate is adapted to limit elongation of said polymeric layer when said substrate is subjected to a flexing action so as to improve durability of the polymeric layer, said polymeric layer including a conductive layer and a resistive layer, said conductive layer forming a buss structure which includes a first buss member electrically connected to a positive polarity and a second buss member electrically connected to a negative polarity; and

an electrical power source connected to said buss structure such that electrical current flows on a path from one of said first and second buss members, to said resistive layer and then to the other of said first and second buss members as the current travels from one of said positive and negative polarities to the other so as to generate heat, said polymeric layer of material being adapted to regulate and distribute the heat.

2. The heater of claim 1, wherein said

conductive layer is applied to said substrate;

and

said resistive layer is applied to said conductive layer.

3. The heater of claim 1, wherein said substrate is an electrically insulative substrate positioned beneath a flexible member, wherein said substrate is made of a polymeric film;

and wherein said

conductive layer is screen printed on said substrate; and

said resistive layer is applied to said conductive layer.

4. The heater device of claim 3, wherein said substrate is a dielectric film substrate.

5. The heater of claim 3, wherein said resistive layer has an increasing resistance in response to an increasing temperature, thereby resulting in a self-regulating temperature characteristic.

6. The heater of claim 3, wherein said substrate includes a plurality of apertures formed therethrough.

7. The heater of claim 3, further comprising a flame retardant material.

8. The heater of claim 3, wherein the heating device is a seat heater for an automobile.

9. A flexible seat heater for a vehicle, said heater comprising:

a substrate having at least one open space extending therethrough;

a polymeric layer of material applied to said substrate in a pattern thereby forming a buss structure, wherein said substrate is adapted to limit elongation of said polymeric layer when said substrate is subjected to a flexing action so as to improve durability of the polymeric layer; and

an electrical power source connected to said buss structure so as to generate heat, said buss structure being adapted to regulate the heat;

wherein said polymeric layer includes a layer of resistive material and a layer of conductive material forming said buss structure for providing electrical current to said layer of resistive material, and wherein said buss structure includes a first buss ground which extends around a periphery of the heater, a first buss in electrical communication with said first buss ground, including at least two serpentine paths extending through an area bounded by said first buss ground, a second buss ground positioned between said at least two serpentine paths, and a second buss located between said first buss ground and said at least two serpentine paths.

10. The heater of claim 9, wherein said at least two serpentine paths include alternating inwardly facing curved portions and outwardly facing curved portions.

11. The heater of claim 10, wherein said second buss ground includes second buss ground extensions which extend into said inwardly facing curved portions of said at least two serpentine paths.

12. The heater of claim 11, wherein said second buss includes second buss extensions which extend into said outwardly facing curved portions of said at least two serpentine paths.

13. The heater of claim 12, wherein said second buss ground extensions and said second buss extensions have circular portions defining apertures therein which pass through the heating device.

14. The heater of claim 13, wherein said second buss includes a first L-shaped portion comprising a first shorter leg and a first longer leg and a second L-shaped portion comprising a second shorter leg and a second longer leg.

15. The heater of claim 14, wherein said first shorter leg and said second shorter leg are colinear along a first edge of the heating device, a space being formed between said first shorter leg and said second shorter leg through which said at least two serpentine paths extend.

16. The heater of claim 15, wherein said first longer leg extends along a second edge of the heating device and said second longer leg extends along a third edge of the heating device, wherein said first longer leg is parallel to said second longer leg.

17. The heater of claim 16, wherein said first longer leg and said second longer leg are perpendicular to said first shorter leg and said second shorter leg.

18. The heater of claim 17, wherein said second buss ground is parallel to said first longer leg and said second longer leg.

19. The heater of claim 18, wherein said at least two serpentine paths include spur portions.

20. The heater of claim 19, wherein said second buss ground extensions include spur portions.

21. The heater of claim 20, wherein said second buss extensions include spur portions.

22. The heater of claim 9, wherein resistance of said resistive layer increases with increasing temperature thereby providing a self-regulating temperature characteristic.

23. The heater of claim 9, wherein said substrate is dielectric.

24. The heater of claim 23, wherein said conductive layer is screen printed over said substrate.

25. The heater of claim 24, wherein said conductive layer is formed from a material chosen from the group consisting of copper, gold, silver, aluminum, carbon, graphitic materials and a conductive polymer.

26. The heater of claim 9, wherein said substrate is an electrically insulative substrate, a conductive layer is screen printed on said substrate, and wherein a resistive layer is applied to said conductive layer.

27. The heater of claim 26, wherein said substrate is a dielectric film substrate.

28. The heater of claim 26, wherein said resistive layer has an increasing resistance in response to an increasing temperature, thereby resulting in a self-regulating temperature characteristic.

29. The heater of claim 26, further comprising a flame retardant material.

30. The heater of claim 26, wherein the heating device is a seat heater for an automobile.

31. A flexible seat heater for a vehicle, said heater comprising:

a flexible substrate capable of being subjected to a flexing action thereby causing at least a portion of said substrate to bend and stretch without adversely affecting how said substrate performs and functions in the heater;

a layer of material applied to said substrate, wherein said substrate is adapted to limit elongation of said polymeric layer when said substrate is subjected to a flexing action so as to improve durability of the polymeric layer, said layer of material including a conductive layer that is made from one or more of conductive metal, copper, silver, gold, aluminum, carbon, graphite, or polymer materials, and said layer of material further including a resistive layer being one of a positive temperature coefficient material or a fixed resistance element, said conductive layer forming a buss structure having a first buss member electrically connected to a positive polarity and a second buss member electrically connected to a negative polarity; and

an electrical power source connected to said buss structure such that electrical current flows on a path from one of said first and second buss members, to said resistive layer and then to the other of said first and second buss members as the current travels from one of said positive and negative polarities to the other so as to generate heat, said buss structure and said resistive layer being adapted to regulate and distribute the heat.