US 11,889,624 B2
Flexible printed circuit board and method of manufacturing flexible printed circuit board
Yoshio Oka, Osaka (JP); Koji Nitta, Osaka (JP); Shoichiro Sakai, Osaka (JP); Yasushi Mochida, Osaka (JP); Tadahiro Kaibuki, Osaka (JP); and Junichi Okaue, Shiga (JP)
Assigned to SUMITOMO ELECTRIC PRINTED CIRCUITS, INC., Shiga (JP); and SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed by SUMITOMO ELECTRIC PRINTED CIRCUITS, INC., Shiga (JP); and SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Filed on Dec. 18, 2020, as Appl. No. 17/126,339.
Claims priority of application No. 2020-003239 (JP), filed on Jan. 10, 2020.
Prior Publication US 2021/0219425 A1, Jul. 15, 2021
Int. Cl. H05K 1/11 (2006.01); H05K 3/40 (2006.01)
CPC H05K 1/118 (2013.01) [H05K 3/40 (2013.01); H05K 2203/068 (2013.01); H05K 2203/0723 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A flexible printed circuit board comprising:
a base film having an insulating property; and
one or more interconnects laminated to at least one surface side of the base film,
wherein each of at least one of the one or more interconnects includes, in a longitudinal direction, a first portion and a second portion that is a portion other than the first portion, an average thickness of the second portion being greater than an average thickness of the first portion,
wherein a ratio of the average thickness of the second portion to the average thickness of the first portion is greater than or equal to 1.5 and less than or equal to 50,
wherein the first portion includes a first plating layer, and the second portion includes the first plating layer and a second plating layer,
wherein the second plating layer is laminated on the first plating layer at a boundary between the first portion and the second portion,
wherein the second portion includes an edge at the boundary between the first portion and the second portion, and
wherein the edge of the second portion includes an upper end edge and a lower end edge of the second plating layer in the longitudinal direction, and at least one of the upper end edge or the lower end edge has a curved shape.