Flexible circuit board having enhanced bending durability

Patent metadata

Field	Value
Publication number	US-10299375-B2
Application number	US-201815923017-A
Country	US
Kind code	B2
Filing date	Mar 16, 2018
Priority date	Sep 24, 2015
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

The present invention provides a flexible circuit board having enhanced bending durability. The flexible circuit board comprises: a first board part; a second board part which extends from one side of the first board part and is thinner than the first board part so as to be bendable; and a third board part which extends from one side of the second board part and is thinner than the second board part so as to be bendable.

First claim

What is claimed is:

1. A flexible circuit board having enhanced bending durability, the flexible circuit board comprising:
a first substrate part;
a second substrate part extending from one side of the first substrate part and parallel to the first substrate part, wherein the second substrate part is thinner than the first substrate part and bendable; and
a third substrate part extending from one side of the second substrate part and thinner than the second substrate part, wherein the third substrate part is bendable, and
wherein the first substrate part comprises:
a first dielectric,
a second dielectric facing an upper surface of the first dielectric,
a third dielectric facing a bottom surface of the first dielectric,
a first ground layer stacked on the first dielectric,
a second ground layer stacked on the bottom surface of the first dielectric,
a third ground layer stacked on the second dielectric,
a fourth ground layer stacked on a bottom surface of the third dielectric, and
a via hole penetrating from the first dielectric to the third dielectric and the first ground layer to the fourth ground layer so that the first ground layer to the fourth ground layer is electrically connected to each other.

2. The flexible circuit board of claim 1 , wherein the second substrate part excludes at least one of the third ground layer and the fourth ground layer which are included in the first substrate part.

3. The flexible circuit board of claim 1 , wherein the third substrate part excludes at least two selected from the group of the second dielectric, the third dielectric, the third ground layer, and the fourth ground layer which are included in the first substrate part.

4. The flexible circuit board of claim 2 , wherein the third substrate part excludes at least two selected from the group of the second dielectric, the third dielectric, the third ground layer, and the fourth ground layer which are included in the first substrate part.

5. The flexible circuit board of claim 1 , wherein the first ground layer and the second dielectric are coupled via a first bonding sheet, the second ground layer and the third dielectric are coupled via a second bonding sheet, and the via hole is formed in the first bonding sheet and the second bonding sheet.

6. The flexible circuit board of claim 5 , further comprising:
a signal line provided on the first dielectric,
wherein the first bonding sheet comprises a pair of first bonding sheets that are positioned on the first dielectric and spaced apart from each other by a first predetermined distance with the signal line therebetween, and provides an inner space partitioned by the first dielectric, the second dielectric and the first bonding sheet, and
wherein the signal line is located in the inner space.

7. The flexible circuit board of claim 6 , wherein a gap between the second ground layer and the fourth ground layer is greater than a gap between the first ground layer and the third ground layer.

8. The flexible circuit board of claim 7 , wherein a plurality of ground holes are formed on the third ground layer and the plurality of ground holes are spaced apart from each other by a second predetermined distance.

9. The flexible circuit board of claim 8 ,
wherein the first ground layer comprises a pair of first ground layers, and the second ground layer comprises a pair of second ground layers,
wherein the third substrate part comprises:
the first dielectric,
the signal line stacked on the first dielectric,
the pair of the first ground layers stacked on the first dielectric and spaced apart from each other by a third predetermined distance with the signal line therebetween, and
the pair of the second ground layers stacked on the bottom surface of the first dielectric and spaced apart from each other by a fourth predetermined distance, and

wherein the signal line includes a first signal line, and a pair of second signal lines branched from the first signal line and positioned parallel to each other.

10. The flexible circuit board of claim 8 ,
wherein the second ground layer comprises a pair of second ground layers,
wherein the third substrate part comprises:
the first dielectric, the signal line stacked on the first dielectric, and the pair of the second ground layers stacked on the bottom surface of the first dielectric and spaced apart from each other by a fifth predetermined distance, and

wherein the signal line includes a first signal line, and a pair of second signal lines branched from the first signal line and positioned in parallel with each other.

11. The flexible circuit board of claim 8 ,
wherein the first ground layer comprises a pair of first ground layers,
wherein the third substrate part comprises the first dielectric, the signal line stacked on the first dielectric, and the pair of the first ground layers stacked on the first dielectric and spaced apart from each other by a sixth predetermined distance with the signal line therebetween, and
wherein the signal line includes a first signal line, and a pair of second signal lines branched from the first signal line and positioned parallel to each other.

12. The flexible circuit board of claim 9 ,
wherein a gap between the pair of second signal lines and the first ground layer is smaller than a gap between the first signal line and the first ground layer.

13. The flexible circuit board of claim 11 ,
wherein a gap between the pair of second signal lines and the first ground layer is smaller than a gap between the first signal line and the first ground layer.

14. The flexible circuit board of claim 8 ,
wherein the first ground layer comprises a pair of first ground layers,
wherein the third substrate part comprises:
the first dielectric,
the signal line stacked on the first dielectric,
the pair of the first ground layers stacked on the first dielectric and spaced apart from each other by a seventh predetermined distance with the signal line therebetween, and
the second ground layer formed on the bottom surface of the first dielectric, and

wherein the second ground layer comprises a pair of line grounds stacked at an eighth predetermined distance with the signal line therebetween, and a mesh ground connecting the pair of the line grounds.

15. The flexible circuit board of claim 8 ,
wherein the first ground layer comprises a pair of first ground layers,
wherein the third substrate part comprises:
the first dielectric,
the signal line stacked on the first dielectric,
the pair of the first ground layers stacked on the first dielectric, and spaced apart from each other by a ninth predetermined distance with the signal line therebetween, and
the second ground layer stacked on the bottom surface of the first dielectric, and

wherein the second ground layer is made of silver paste.

16. The flexible circuit board of claim 1 , wherein the first substrate part further comprises a plurality of via holes, wherein respective plurality of via holes penetrate from the first dielectric to the third dielectric and the first ground layer to the fourth ground layer so that the first ground layer to the fourth ground layer is electrically connected to each other.

Assignees

• Gigalane Co Ltd

Inventors

• Kim Sang Pil
• Lee Da Yeon
• Koo Hwang Sub
• Kim Hyun Je
• Jung Hee Seok

Classifications

• H05K1/0225

  Single or multiple openings in a shielding, ground or power plane (H05K1/0227 takes precedence) · CPC title

• H05K2201/093

  Layout of power planes, ground planes or power supply conductors, e.g. having special clearance holes therein · CPC title

• H05K1/028 Primary

  Bending or folding regions of flexible printed circuits (H05K1/0283 takes precedence) · CPC title

• H05K3/4691

  Rigid-flexible multilayer circuits comprising rigid and flexible layers, e.g. having in the bending regions only flexible layers · CPC title

• H05K3/0026

  by laser ablation · CPC title