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US 2019/0297728 A1Published application
Flexible printed circuit to mitigate cracking at through-holes
AssigneeCommScope, Inc. of North Carolina
InventorsBrian J. FITZPATRICK, Jeffrey COOK, Jitendra HANSALIA, Amid Ihsan HASHIM
Life of this patent
Estimating the term…
Abstract
Flexible fingers for flexible printed circuits improve the crack resistance of prior art designs. The crack resistance can be improved by encapsulating the trace inside additional layers such that the outer two layers include only the lands of the through-hole, and all other copper is etched away. The crack resistance can also be improved with strategically adding copper on layers other than the trace layer including attaching is to the land of the through-hole as a stub. These two designs can be combined to include a stub trace into a four-layered design.
Claims18
A flexible finger for a flexible printed circuit;
- the flexible finger comprising:
- (a) a flexible multi-layered construction defining a through-hole in the construction;
- the multi-layered construction including,
- (i) a flexible substrate having first and second opposing surfaces;
- (ii) a conductive trace on the first surface;
- (iii) an inner conductive layer on the second surface;
- (iv) a first film layer secured to and covering the conductive trace;
- (v) a second film layer secured to and covering the inner conductive layer;
- (vi) a first conductive outer layer on the first film layer;
- (vii) a second conductive outer layer on the second film layer;
- and
- (viii) externally exposed plating lining the through-hole and covering the first conductive outer layer and second conductive outer layer;
- the plating being limited to a region adjacent to the through-hole, the region having an outer periphery;
- and
- wherein the inner conductive layer, first conductive outer layer, and second conductive outer layer circumscribe the through-hole and do not extend beyond the outer periphery of the region of the plating;
- and
- wherein the conductive trace in the multi-layered construction is the only functioning conductive trace.
14 more elements
A flexible finger for a flexible printed circuit, the flexible finger comprising:
- (a) a flexible multi-layered construction defining a through-hole in the construction;
- the multi-layered construction including,
- (i) a flexible substrate having first and second opposing surfaces;
- (ii) a conductive trace on the first surface;
- (iii) a conductive layer on the second surface;
- (iv) plating lining the through-hole and including (i) a first plating layer circumscribing the through hole and covering the conductive trace and (ii) a second plating layer circumscribing the through-hole and covering the entire conductive layer;
- (b) a first film coverlay covering a portion of the first plating layer and leaving the first plating layer exposed and uncovered at a region circumscribing the through hole;
- (c) a second film coverlay covering a portion of the second plating layer and leaving the second plating layer exposed and uncovered at the region circumscribing the through hole;
- and
- wherein the conductive trace in the multi-layered construction is the only functioning conductive trace.
7 more elements
A flexible finger for a flexible printed circuit;
- the flexible finger comprising:
- (a) a flexible multi-layered construction defining a through-hole in the construction;
- the multi-layered construction including,
- (i) a flexible substrate having first and second opposing surfaces;
- (ii) a conductive trace on the first surface;
- (iii) an inner conductive layer on the second surface;
- (iv) a first film layer secured to and covering the conductive trace;
- (v) a second film layer secured to and covering the inner conductive layer;
- (vi) a first conductive outer layer on the first film layer;
- (vii) a second conductive outer layer on the second film layer;
- and
- (viii) externally exposed plating lining the through-hole and covering the first conductive outer layer and second conductive outer layer;
- the plating being limited to a region adjacent to the through-hole, the region having an outer periphery;
- and
- wherein the inner conductive layer, first conductive outer layer, and second conductive outer layer circumscribe the through-hole;
- wherein the first conductive outer layer and second conductive outer layer do not extend beyond the outer periphery of the region of the plating;
- and
- wherein the conductive trace in the multi-layered construction is the only functioning conductive trace.
15 more elements
A method for mitigating cracking of conductive traces of a flexible finger of a flexible printed circuit;
- the method comprising:
- (a) providing a flexible substrate having a conductive trace on a first surface and an inner conductive layer on a second surface;
- the flexible substrate, conductive trace, and inner conductive layer defining a through hole;
- (b) covering the conductive trace with a first film layer;
- (c) covering the inner conductive layer with a second film layer;
- (d) providing a first conductive outer layer on the first film layer;
- (e) providing a second conductive outer layer on the second film layer;
- and
- (f) providing externally exposed plating to line the through-hole and cover the first conductive outer layer and second conductive outer layer;
- the plating being limited to a region adjacent to the through-hole, the region having an outer periphery;
- wherein the inner conductive layer, first conductive outer layer, and second conductive outer layer circumscribe the through-hole and do not extend beyond the outer periphery of the region of the plating;
- and
- wherein the conductive trace in the multi-layered construction is the only functioning conductive trace.
10 more elements
A method for mitigating cracking of conductive traces of a flexible finger of a flexible printed circuit, the method comprising:
- (a) providing a flexible substrate having a conductive trace on a first surface and a conductive layer on a second surface;
- the flexible substrate, conductive trace, and conductive layer defining a through-hole;
- (b) lining the through-hole with plating and including (i) a first plating layer circumscribing the through hole and covering the conductive trace and (ii) a second plating layer circumscribing the through-hole and covering the entire conductive layer;
- (c) covering a portion of the first plating layer with a first film coverlay and leaving the first plating layer exposed and uncovered at a region circumscribing the through hole;
- (d) covering a portion of the second plating layer a with second film coverlay and leaving the second plating layer exposed and uncovered at the region circumscribing the through hole;
- and
- wherein the conductive trace in the multi-layered construction is the only functioning conductive trace.
4 more elements
A method for mitigating cracking of conductive traces of a flexible finger of a flexible printed circuit, the method comprising:
- (a) providing a flexible substrate having a conductive trace on a first surface and an inner conductive layer on a second surface;
- (b) providing a first film layer secured to and covering the conductive trace;
- (c) providing a second film layer secured to and covering the inner conductive layer;
- (d) providing a first conductive outer layer on the first film layer;
- (e) providing a second conductive outer layer on the second film layer;
- wherein the flexible substrate, conductive trace, inner conductive layer, first film layer, second film layer, first conductive outer layer, and second conductive outer layer define a through-hole;
- (f) lining the through-hole with externally exposed plating and covering the first conductive outer layer and second conductive outer layer;
- the plating being limited to a region adjacent to the through-hole, the region having an outer periphery;
- and
- wherein the inner conductive layer, first conductive outer layer, and second conductive outer layer circumscribe the through-hole;
- wherein the first conductive outer layer and second conductive outer layer do not extend beyond the outer periphery of the region of the plating;
- and
- wherein the conductive trace in the multi-layered construction is the only functioning conductive trace.
10 more elements
Dependencies are inferred from the claim text.