Signal Trace Patterns for Flexible Substrates

• US 20160103534A1
• Filed: 10/10/2014
• Published: 04/14/2016
• Est. Priority Date: 10/10/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Drzaic, Paul S., Tao, Yi, Zhang, Zhen
• Granted Patent: US 9,600,112 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 1/169 the I/O peripheral being an integrated pointing device, e.g. trackball in the palm rest area, mini-joystick integrated between keyboard keys, touch pads or touch stripes G06F1/1643 takes precedence; constructional details of pointing devices G06F3/033
• CPC Class Codes: G06F 2203/04102 Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: H05K 1/028 Bending or folding regions of flexible printed circuits H05K1/0283 takes precedence
• CPC Class Codes: H05K 1/0281 Reinforcement details thereof
• CPC Class Codes: H05K 1/0296 Conductive pattern lay-out details not covered by sub groups H05K1/02 - H05K1/0295 H05K1/11 takes precedence; lay-out adapted to mounted component configuration H05K1/18
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 2201/09263 Meander
• CPC Class Codes: H05K 2201/09663 Divided layout, i.e. conductors divided in two or more parts branched layout H05K2201/09254
• CPC Class Codes: H05K 2201/09672 Superposed layout, i.e. in different planes parallel traces in one plane H05K2201/09236
• CPC Class Codes: H05K 2201/0979 Redundant conductors or connections, i.e. more than one current path between two points
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]

Abstract

A flexible substrate may have one or more bends. A bend in a flexible substrate may be made along a bend axis. Conductive traces in the flexible substrate may have elongated shapes. Each conductive trace may extend along a longitudinal axis that is perpendicular to the bend axis. Metal or other conductive materials may form the conductive traces. The traces may be formed from a chain of linked segments. Each segment may have patterned trace portions that surround one, two, or more than two openings. Traces may also be formed that have multiple layers of metal or other conductive material interconnected using vias. A polymer layer may cover the traces to align a neutral stress plane with the traces and to serve as a moisture barrier layer.

Claims

1. Apparatus, comprising:

a flexible substrate layer having a bend; and

conductive traces on the flexible substrate layer that overlap the bend, wherein each conductive trace is formed from a chain of interconnected segments, each segment enclosing at least one opening.

2. The apparatus defined in claim 1 wherein the flexible substrate layer comprises a flexible polymer layer.

3. The apparatus defined in claim 2 wherein the conductive traces each extend along a longitudinal axis, wherein the bend is formed around a bend axis, and wherein the longitudinal axis of each trace is perpendicular to the bend axis.

4. The apparatus defined in claim 3 wherein the conductive traces comprise metal traces.

5. The apparatus defined in claim 4 wherein the metal traces have a first portion formed in a first layer of metal and a second portion formed in a second layer of metal.

6. The apparatus defined in claim 5 further comprising a plurality of metal vias that interconnect the first portion and the second portion.

7. The apparatus defined in claim 6 wherein the first portion and second portion have meandering shapes that intersect at a plurality of locations and wherein at least one of the metal vias couples the first portion to the second portion at each of the locations.

8. The apparatus defined in claim 4 wherein each segment encloses two openings.

9. The apparatus defined in claim 4 further comprising pixels that contain light-emitting diodes on the flexible substrate layer.

10. The apparatus defined in claim 9 wherein the pixels are organized in an array of rows and columns forming an active area for a display in which images are produced and wherein the bend is formed in an inactive area of the display in which images are not produced.

11. The apparatus defined in claim 4 further comprising:

a dielectric coating over the metal traces.

12. The apparatus defined in claim 11 wherein the dielectric coating has a thickness such that a neutral stress plane for the flexible substrate layer is aligned with the metal trace.

13. The apparatus defined in claim 12 wherein the dielectric coating is a moisture barrier coating.

14. An apparatus, comprising:

a flexible polymer substrate having a bend; and

conductive traces on the flexible polymer substrate that overlap the bend, wherein each conductive trace has a chain of interconnected sections, each section having a pattern of traces that encloses at least two openings.

15. The apparatus defined in claim 14 wherein the conductive traces each extend along a longitudinal axis, wherein the bend is formed around a bend axis, and wherein the longitudinal axis of each trace is perpendicular to the bend axis.

16. The apparatus defined in claim 15 further comprising pixels that contain light-emitting diodes, wherein the conductive traces carry display signals.

17. The apparatus defined in claim 16 wherein the pixels are organized in an array of rows and columns that forms an active area for a display in which images are produced and wherein the bend is formed in an inactive area of display in which images are not produced.

18. The apparatus defined in claim 17 further comprising:

a polymer coating over the conductive traces that serves as a moisture barrier.

19. A flexible structure that overlaps a bend axis, comprising:

a flexible polymer layer that bends at the bend axis;

conductive traces on the flexible substrate layer that overlap the bend, wherein each conductive trace has a chain of linked metal trace segments each of which encloses at least one opening; and

a dielectric coating over the conductive traces.

20. The flexible structure defined in claim 19 wherein the dielectric coating comprises a moisture barrier, wherein each conductive trace is formed from overlapping meandering lines, and wherein the overlapping meandering lines are shorted together using metal vias.