Printed circuit board

• US 5,360,949 A
• Filed: 02/03/1994
• Issued: 11/01/1994
• Est. Priority Date: 06/30/1993
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Duxbury, Guy M.
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): Figlin, Cheryl R.
• Application Number:
  US08/190,933
• Time in Patent Office: 271 Days
• Field of Search: 174/250, 174/251, 174/254, 174/261, 361/784, 361/792
• US Class Current: 174/250
• CPC Class Codes: H01B 7/0861 comprising one or more screens
• CPC Class Codes: H05K 1/0224 Patterned shielding planes, ground planes or power planes H05K1/0253 takes precedence
• CPC Class Codes: H05K 1/0253 Impedance adaptations of transmission lines by special lay-out of power planes, e.g. providing openings H05K1/0251 takes precedence
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 2201/0715 provided by an outer layer of PCB
• CPC Class Codes: H05K 2201/093 Layout of power planes, ground planes or power supply conductors, e.g. having special clearance holes therein
• CPC Class Codes: H05K 2201/09681 Mesh conductors, e.g. as a ground plane

Abstract

A plurality of pairs of parallel conductive wires are supported by a flexible non-conductive sheet, equidistant from two conductive ground meshes which sandwich the wires therebetween. Each mesh forms a matrix, defining an array of intersecting conductors. The offset of the intersections from the conductive wires incrementally changes along the longitudinal axes of the pair of conductive wires. This ensures the capacitance between each conductive wire and the mesh is substantially balanced regardless of where the conducive wires run, so that cross talk between the pairs of conductive wires will remain relatively low.

Claims

1. A printed circuit board for electrically interconnecting electronic components, comprising:

a non-conductive supporting member;

a conductive mesh supported by the supporting member, the conductive mesh defining an array of intersecting conductors; and

at least one pair of parallel conductive wires supported by the supporting member equidistant from the conductive mesh,

wherein the longitudinal axes of the pair of conductive wires are oriented at an angle relative to intersections of the conductors of the conductive mesh, so that the offset of the intersections from the conductive wires incrementally changes along the longitudinal axes of the pair of conductive wires so that the capacitances between the conductive wires and the conductive mesh are substantially balanced regardless of the lateral position of the wires.

2. The printed circuit board of claim 1, wherein the supporting member is a flexible non-conductive one.

3. The printed circuit board of claim 1 or 2, wherein the conductive mesh is a first conductive mesh, and the printed circuit board includes a second conductive mesh defining an array of intersecting conductors, the second conductive mesh being supported by the supporting member parallel to said conductive mesh, wherein:

the parallel conductive wires are sandwiched between and substantially equidistant from each of the conductive meshes; and

the longitudinal axes of the pair of conductive wires are oriented at an angle relative to the intersections of the conductors of both of the conductive meshes.

4. The printed circuit board of claim 3, wherein the conductors of said conductive mesh are substantially parallel to those of the second conductive mesh.

5. The printed circuit board of claim 3, wherein:

the conductors of said conductive mesh are substantially parallel to those of the second conductive mesh; and

the pitch of the intersections of both of the conductive meshes is substantially identical.

6. The printed circuit board of claim 5, wherein the conductors of said conductive mesh in plan view are off-set from the conductors of the second conductive mesh.

7. The printed circuit board of claim 1, wherein the conductive mesh and the conductive wires are defined by:

space="preserve" listing-type="equation">S=D/((sin φ

)×

n×

√

2);

in which, S is the distance between the conductors of the conductive mesh;

D is the distance between the parallel conductive wires of one pair;

φ

is the angle between the longitudinal axes of the pair of conductive wires and the direction of the intersections of the conductors of the conductive mesh; and

n is the number of intersections of the mesh between the points where the conductive wires cross a line oriented at the angle φ

.

8. The printed circuit board of claim 1, 3 or 7, wherein the angle between the longitudinal axes of the pair of conductive wires and the direction of the intersections of the conductors of the conductive mesh is less than about 7°

.