Flexible Printed Circuit Board

Abstract

A flexible printed circuit board comprises a conducting layer that includes a first signal line, a first ground plane and a second ground plane. A first shielding via extends from a third ground plane to a fourth ground plane and extends through the first ground plane to electrically connect the first ground plane, the third ground plane and the fourth ground plane. A second shielding via extends from the third ground plane to the fourth ground plane. The first ground plane, the second ground plane, the third ground plane, the fourth ground plane, the first shielding via and the second shielding via, together, circumferentially surround the first signal line to minimize electromagnetic interference with the first signal line.

1 . A flexible printed circuit board, comprising:
 a conducting layer including a first signal line, a first ground plane and a second ground plane;   a first ground plane layer including a third ground plane;   a second ground plane layer including a fourth ground plane; and   a first shielding via extending from the third ground plane to the fourth ground plane and extending through the first ground plane to electrically connect the first ground plane, the third ground plane and the fourth ground plane; and   a second shielding via extending from the third ground plane to the fourth ground plane and extending through the second ground plane to electrically connect the second ground plane, the third ground plane and the fourth ground plane,   the first ground plane, the second ground plane, the third ground plane, the fourth ground plane, the first shielding via and the second shielding via, together, circumferentially surrounding the first signal line to minimize electromagnetic interference with the first signal line.   
     
     
         2 . The flexible printed circuit board of  claim 1 , wherein the first signal line is positioned between the first ground plane and the second ground plane. 
     
     
         3 . The flexible printed circuit board of  claim 1 , wherein the first signal line is positioned between the third ground plane and the fourth ground plane. 
     
     
         4 . The flexible printed circuit board of  claim 1 , wherein the first signal line is positioned between the first shielding via and the second shielding via. 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . The flexible printed circuit board of  claim 1 , further comprising:
 a first dielectric plane positioned between the first signal line and the third ground plane.   
     
     
         8 . The flexible printed circuit board of  claim 1 , further comprising:
 a second dielectric plane positioned between the first signal line and the fourth ground plane.   
     
     
         9 . The flexible printed circuit board of  claim 1 , further comprising:
 a second signal line, a fifth ground plane and a sixth ground plane at the conducting layer, the second signal line being separate and distinct from the first signal line;   a seventh ground plane at the first ground plane layer;   an eighth ground plane at the second ground plane layer;   a third shielding via extending from the seventh ground plane to the eighth ground plane and extending through the fifth ground plane to electrically connect the fifth ground plane, the seventh ground plane and the eighth ground plane; and   a fourth shielding via extending from the seventh ground plane to the eighth ground plane and extending through the sixth ground plane to electrically connect the sixth ground plane, the seventh ground plane and the eighth ground plane,   the fifth ground plane, the sixth ground plane, the seventh ground plane, the eighth ground plane, the second shielding via and the third shielding via, together, circumferentially surrounding the second signal line to minimize electromagnetic interference with the second signal line.   
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . The flexible printed circuit board of  claim 9 , further comprising a dielectric plane positioned between the third ground plane and the seventh ground plane at the first ground plane layer to electromagnetically isolate the third ground plane and the seventh ground plane. 
     
     
         13 . The flexible printed circuit board of  claim 9 , further comprising a dielectric plane positioned between the second ground plane and the fifth ground plane at the conducting layer to electromagnetically isolate the second ground plane and the fifth ground plane. 
     
     
         14 . The flexible printed circuit board of  claim 9 , further comprising a dielectric plane positioned between the fourth ground plane and the eighth ground plane at the second ground plane layer to electromagnetically isolate the fourth ground plane and the eighth ground plane. 
     
     
         15 - 28 . (Canceled) 
     
     
         29 . A flexible printed circuit board including:
 a conducting layer including a first signal line and a second signal, the first signal line having a first physical length and a first electrical length and the second signal line having a second physical length and a second electrical length, the physical length of the first signal line being different from the physical length of the second signal line such that a difference between the first electrical length and the second electrical length is less than one electrical degree.   
     
     
         30 . The flexible printed circuit board of  claim 29 , wherein the physical length of the first signal line being different from the physical length of the second signal line such that a difference between the first electrical length and the second electrical length is less than one-half of an electrical degree. 
     
     
         31 . The flexible printed circuit board of  claim 29 , wherein the physical length of the first signal line being different from the physical length of the second signal line such that a difference between the first electrical length and the second electrical length is less than one-quarter of an electrical degree. 
     
     
         32 . The flexible printed circuit board of  claim 29 , wherein the conducting layer includes:
 a first ground plane, a second ground plane, a third ground plane and a fourth ground plane, wherein the first signal line is positioned between the first ground plane and the second ground plane and wherein the second signal line is positioned between the third ground plane and the fourth ground plane.   
     
     
         33 . The flexible printed circuit board of  claim 29 , further comprising:
 A first dielectric layer and a second dielectric layer, the first signal line and the second signal line being positioned between the first dielectric layer and the second dielectric layer.   
     
     
         34 . A method for manufacturing a flexible printed circuit board, comprising:
 providing a conducting layer including a first signal line and a second signal, the first signal line having a first physical length and a first electrical length and the second signal line having a second physical length and a second electrical length,   adjusting the physical length of the first signal line to be different from the physical length of the second signal line such that a difference between the first electrical length and the second electrical length is less than one electrical degree.   
     
     
         35 . The method of  claim 34 , wherein the physical length of the first signal line being different from the physical length of the second signal line such that a difference between the first electrical length and the second electrical length is less than one-half of an electrical degree. 
     
     
         36 . The method of  claim 34 , wherein the physical length of the first signal line being different from the physical length of the second signal line such that a difference between the first electrical length and the second electrical length is less than one-quarter of an electrical degree. 
     
     
         37 . The method of  claim 34 , wherein the conducting layer includes: a first ground plane, a second ground plane, a third ground plane and a fourth ground plane, the method further comprising:
 positioning the first signal line between the first ground plane and the second ground plane; and   positioning the second signal line between the third ground plane and the fourth ground plane.   
     
     
         38 . The method of  claim 34 , further comprising:
 providing a first dielectric layer and a second dielectric layer; and   positioning the first signal line and the second signal line between the first dielectric layer and the second dielectric layer.