Heater for extreme convex mirrors or irregular shapes

Abstract

A heater for a non-planar mirror may be provided on a polymer substrate that has been cut to allow flexible movement in the x, y and z axes, for example, by cutting the substrate in a generally long, narrow s-shape. By allowing flexible movement and overlapping on itself when attached to a non-planar surface, uniform adhesion is achieved over substantially the entire surface to be heated. In aspects of the invention, the heater may be screen printed on the substrate and have electrical connections attached at opposite ends of the substrate to provide comparable current flow paths across essentially the full heater surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a top plan view of the shape of the substrate of a heating device of an embodiment of the present invention.

FIG. 1 b is a top plan view of the heating device of FIG. 1a.

FIG. 2 is a perspective view of an embodiment of the invention adhered to the inner surface of an exemplary extreme convex mirror.

FIG. 3 is a perspective view of the outer surface of the exemplary extreme convex mirror of FIG. 2.

Claims

1. A heating device for non-planar mirror surfaces comprising: a polymer sheet substrate defining a continuous generally s-shaped configuration; anda heater screen printed on a surface of the substrate, the heater comprising at least one electrical bus extending the length of the substrate and having a positive electrical connection near a first end of the substrate and a negative electrical connection near a second end of the substrate.

2. The heating device of claim 1 wherein the heater further comprises a positive temperature coefficient material.

3. The heating device of claim 1 wherein the heater further comprises electrical traces extending from the at least one bus to substantially cover the surface area of the substrate.

4. The heating device of claim 3 wherein the traces comprise conductive material flakes mixed with a conductive polymer.

5. The heating device of claim 1 wherein the at least one electrical bus comprises a conductive polymer and a material chosen from the group consisting of copper, gold, silver, aluminum, carbon, and graphitic materials.

6. The heating device of claim 1 wherein the substrate defines a thickness between approximately 0.004 inches and 0.010 inches.

7. The heating device of claim 1 wherein the substrate comprises polyester.

8. A heating device for non-planar mirror surfaces comprising: a substrate, the substrate cut to provide a generally long, generally narrow continuous material having a plurality of generally linear sections connected at alternating ends to substantially cover an area; anda heater disposed on a surface of the substrate, the heater comprising at least one electrical bus that extends essentially the full length of the substrate, the at least one bus including a plurality of traces extending radially to substantially cover the surface of the substrate.

9. The heating device of claim 8 wherein the heater is connected at a first end with a positive electrical connection and at a second end with a negative electrical connection.

10. The heating device of claim 8 further comprising a chemical resistive laminate disposed on the heater.

11. The heating device of claim 8 wherein the substrate may overlap itself when attached to the non-planar surface.

12. The heating device of claim 8 wherein the heater further comprises a positive temperature coefficient material.

13. The heating device of claim 8 wherein the at least one electrical bus comprises a conductive polymer and a material chosen from the group consisting of copper, gold, silver, aluminum, carbon, and graphitic materials.

14. The heating device of claim 8 wherein the substrate comprises polyester.

15. A heating device for non-planar mirror surfaces comprising: a polyester substrate cut into a continuous, generally narrow shape to allow flexing and overlapping during disposition of the substrate on the non-planar surface, the substrate substantially covering an area of the non-planar surface with generally uniform adhesion; anda heater screen printed on a surface of the substrate, the heater comprising: a conductive layer including a first bus and a second bus, the first and second busses disposed generally along a first and a second longitudinal edge of the substrate, and a plurality of traces extending from the first and second busses to distribute heat over the surface of the substrate;a positive electrical connection disposed at an end of the first bus and a negative electrical connection disposed at an opposing end of the second bus; anda resistive layer disposed on the conductive layer, the resistive layer comprising a thick polymer film.

16. The heating device of claim 15 wherein the traces comprise conductive material flakes mixed with a conductive polymer.

17. The heating device of claim 15 wherein at least some of the traces comprise spurs extending outwardly from the traces.

18. The heating device of claim 15 wherein the resistive layer comprises a positive temperature coefficient material.

19. The heating device of claim 15 wherein the first and second electrical busses comprise a conductive polymer and a material chosen from the group consisting of copper, gold, silver, aluminum, carbon, and graphitic materials.

20. The heating device of claim 15, wherein the substrate defines a thickness between approximately 0.004 inches and 0.010 inches.