Electrical resistance device

• US 5,019,797 A
• Filed: 09/29/1989
• Issued: 05/28/1991
• Est. Priority Date: 01/11/1988
• Status: Expired due to Fees

• Current Assignee: Calorique Limited
• Original Assignee: Flexwatt Corporation
• Inventors: Grise, Frederick G. J., Bodensiek, Paul H., Marstiller, John A.
• Primary Examiner(s): Reynolds, Bruce A.
• Assistant Examiner(s): Lateef, Marvin M.
• Application Number:
  US07/414,532
• Time in Patent Office: 606 Days
• Field of Search: 219/455, 219/345, 219/532, 219/545, 219/546, 219/548, 219/549, 219/541, 219/543, 219/553, 219/443, 338/206, 338/217, 338/295, 338/333, 338/306
• US Class Current: 338/333
• 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 2203/037 Heaters with zones of different power density
• CPC Class Codes: H05B 3/10 Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
• CPC Class Codes: H05B 3/26 heating conductor mounted on insulating base for transparent areas H05B3/84, H05B3/86
• CPC Class Codes: H05B 3/36 heating conductor embedded in insulating material

Abstract

An electrical resistance device includes a conductive metal pattern carried on an insulating surface. A portion of the conductive metal pattern includes a two-dimensional array of areas devoid of conductive material ("voids") within a mesh of conductive material. Typically, the voids are hexagonal and are arranged such that the adjacent edges of adjacent hexagons are parallel to each other and spaced apart a distance not more than about 0.10 in. The hexagonal voids typically are arranged so that the centers of sets of three adjacent voids lie on the corners of equilateral triangles.

Claims

1. An electrical resistance device including a conductive metal pattern carried on an insulating surface, said device being characterized in that

a portion of said conductive metal pattern includes a two-dimensional array of substantially identical areas of said substrate devoid of conductive material ("voids") within a mesh of conductive material on said substrate, said voids being arranged such that the centers of sets of three adjacent voids are positioned at the corners of triangles and the overall direction of current flow in said device is generally not parallel to sides of said triangles.

2. The resistance device of claim 1 further characterized in that said voids are regular polygons.

3. The resistance device of claim 2 further characterized in that said voids are arranged such that the sides of adjacent voids are parallel to each other and said voids are regularly spaced.

4. The resistance device of claim 3 further characterized in that said voids are hexagons and that the centers of sets of three adjacent voids are positioned at the corners of equilateral triangles.

5. The resistance device of claim 4 further characterized in hexagons are arranged such that the overall direction of current flow in said device is not parallel to sides of said triangles.

6. The resistance device of claim 1 further characterized in that the width of conductive material of said mesh intermediate adjacent ones of said voids is not more than about 0.010 in.

7. The resistance device of claim 1 further characterized in that a second portion of said conductive pattern contiguous to said first mentioned portion has a resistivity (ohms per square) different from that of said first-mentioned portion.

8. The resistance device of claim 7 wherein said first-mentioned portion and said second portion each comprises a respective regular two-dimensional array of voids within a mesh of conductive material.

9. The resistance device of claim 8 wherein at least one of the distance between the centers of the voids and the size of the voids in said first portion is different than the distance between the center of the voids and the size of the voids in said second portion.

10. The resistance device of claim 9 wherein said voids are hexagons, and are arranged such that the sides of adjacent hexagons are parallel to each other.

11. The resistance device of claim 1 wherein said pattern comprises metal deposited on said substrate at substantially uniform thickness.

12. The resistance device of claim 11 wherein said thickness is less than about 100 Angstroms.

13. The resistance device of claim 11 wherein said metal is silver or nickel.