Printed circuit board and method of manufacturing printed circuit board

Abstract

A printed circuit board ( 100 ) has a conductor layer (ground layer ( 70 )), a signal layer ( 25 ) having a signal line ( 20 ) provided so as to oppose the conductor layer (ground layer ( 70 )), and an insulating resin layer ( 60 ) disposed between the conductor layer (ground layer ( 70 )) and the signal layer ( 25 ), the insulating resin layer ( 60 ) has voids in an overlapping location, in a plan view, with the signal line ( 20 ), and the voids ( 40 ) are communicated with the outside of the printed circuit board ( 100 ).

1 - 17 . (canceled) 
     
     
         18 . A flexible printed circuit board comprising a conductor layer, a signal layer having a signal line provided so as to oppose the conductor layer, and an insulating resin layer disposed between the conductor layer and the signal layer,
 the insulating resin layer having a void in an overlapping location, in a plan view, with the signal line, and the void being communicated with the outside of the flexible printed circuit board.   
     
     
         19 . The flexible printed circuit board according to  claim 18 ,
 wherein the void has an opening through which communication with the outside is established, and   the opening is provided in a different location from the signal line.   
     
     
         20 . The flexible printed circuit board according to  claim 18 ,
 wherein the void extends through the insulating resin layer in the thickness direction, and   the insulating resin layer is zoned into an insulating resin part containing the insulating resin, and the void.   
     
     
         21 . The flexible printed circuit board according to  claim 18 ,
 wherein the void has an opening through which communication with the outside is established,   the opening is provided in a different location from the signal line,   the void extends through the insulating resin layer in the thickness direction,   the insulating resin layer is zoned into an insulating resin part containing the insulating resin, and the void, and   comprising two or more voids not communicating with each other, and the opening is provided to every void.   
     
     
         22 . The flexible printed circuit board according to  claim 18 ,
 wherein, in a plan view, the void is formed so as to extend in the width direction of the signal line.   
     
     
         23 . The flexible printed circuit board according to  claim 22 ,
 wherein the signal layer has a plurality of signal lines arranged in parallel to each other, and, in all of the plurality of signal lines arranged in parallel, the void resides, in a plan view, so as to extend in the width direction.   
     
     
         24 . The flexible printed circuit board according to  claim 22 ,
 the signal line has a larger width in the region overlapped with the void, than in other region different from that region.   
     
     
         25 . The flexible printed circuit board according to  claim 18 ,
 wherein the void has an opening through which communication with the outside is established, and the opening is provided on the outer rim of the flexible printed circuit board.   
     
     
         26 . The flexible printed circuit board according to  claim 18 ,
 wherein the void has an opening through which communication with the outside is established, and the opening is provided on the top face or back face of the flexible printed circuit board.   
     
     
         27 . The flexible printed circuit board according to  claim 20 , further comprising:
 a through-hole which extends through the insulating resin layer; and   the insulating resin part being provided, in the insulating resin layer, around the through-hole.   
     
     
         28 . The flexible printed circuit board according to  claim 18 ,
 wherein the signal layer has a first signal line and a second signal line which are different in path lengths, the path length of the first signal line being longer than the path length of the second signal line, and the length over which the first signal line crosses the void being longer than the length over which the second signal line crosses the void.   
     
     
         29 . The flexible printed circuit board according to  claim 18 , further comprising:
 a first conductor layer opposed to one face of the signal line, and a second conductor layer opposed to the other face of the signal line, and, a first insulating resin layer provided between the signal line and the first conductor layer, and a second insulating resin layer provided between the signal line and the second conductor layer, and   in a plan view, a first void provided in the first insulating resin layer and a the second the void provided in the second insulating resin layer cross the signal line, and have a form symmetrical about the signal line.   
     
     
         30 . A method of manufacturing a flexible printed circuit board having a conductor layer, a signal layer having a signal line provided so as to oppose the conductor layer, and an insulating resin layer disposed between the conductor layer and the signal layer, the method comprising:
 a void forming step forming a void in the plane of an insulating resin film;   a substrate forming step forming a substrate by providing the signal line on one face of the insulating resin film obtained in the void forming step, in an overlapping location in a plan view with the void, and by providing the conductor layer on the other side, to thereby form a substrate which comprises the insulating resin layer having the insulating resin film provided with the void, and the signal line and the conductor layer which are opposed to each other while placing the insulating resin layer in between; and   an opening forming step forming an opening through which communication between the void, provided in the substrate obtained by the substrate forming step, and the gas phase outside the substrate is established.   
     
     
         31 . The method of manufacturing a flexible printed circuit board according to  claim 30 ,
 wherein the void forming step further comprises forming the void in the plane of the insulating resin film and in a predetermined location other than in the outer rim, so as to extend through the film in the thickness direction, and,   the opening forming step further comprises forming the opening on the outer rim of the substrate.   
     
     
         32 . The method of manufacturing a flexible printed circuit board according to  claim 30 , further comprising:
 a trimming step cutting an arbitrary portion of the outer rim of the substrate in order to shape the appearance,   wherein, in the trimming step, the end portion of the void is cut together to form the opening, that is, to concurrently carry out the opening forming step.   
     
     
         33 . The method of manufacturing a flexible printed circuit board according to  claim 30 ,
 wherein in the opening forming step, the opening is formed in a plan view in a location different from the location where the signal line is formed.   
     
     
         34 . The method of manufacturing a flexible printed circuit board according to  claim 33 ,
 wherein the opening forming step comprises a step of forming the opening by irradiating laser light to the void from the outside of the substrate.   
     
     
         35 . The flexible printed circuit board according to  claim 23 ,
 the signal line has a larger width in the region overlapped with the void, than in other region different from that region.   
     
     
         36 . The method of manufacturing a flexible printed circuit board according to  claim 31 ,
 wherein in the opening forming step, the opening is formed in a plan view in a location different from the location where the signal line is formed.   
     
     
         37 . The method of manufacturing a flexible printed circuit board according to  claim 36 ,
 wherein the opening forming step comprises a step of forming the opening by irradiating laser light to the void from the outside of the substrate.