Electronic device with signal line routing to minimize vibrations

Patent metadata

Field	Value
Publication number	US-9460838-B2
Application number	US-201514831109-A
Country	US
Kind code	B2
Filing date	Aug 20, 2015
Priority date	Sep 2, 2014
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

An electronic device may have a source of magnetic field such as a magnet that produces a static magnetic field. A flexible printed circuit may have a flexible tail that surrounds a central portion. The central portion may overlap the magnet. Electrical components may be mounted to the central portion. To prevent undesired vibrations and noise due to interactions between magnetic fields induced by signals flowing in signal lines in the flexible printed circuit and the static magnetic field, the signal lines may be vertically stacked or may be routed along a curved path that does not overlap the magnet. The tail may serve as a service loop that allows a portion of a housing for the device and electrical components mounted to the central portion in alignment with windows in the housing to be detached for servicing.

First claim

What is claimed is:

1. Apparatus, comprising:
a permanent magnet that produces a static magnetic field;
a light-emitting diode;
a printed circuit on which the light-emitting diode is mounted, wherein the printed circuit overlaps the permanent magnet so that the static magnetic field passes through the printed circuit and the light-emitting diode is mounted to the printed circuit in the vicinity of the permanent magnet; and
signal lines on the printed circuit that are coupled to the light-emitting diode, wherein the signal lines produce a second magnetic field and are configured to minimize vibrations in the printed circuit due to interactions between the static magnetic field and the second magnetic field.

2. The apparatus defined in claim 1 wherein the signal lines are vertically stacked to minimize interactions between the static magnetic field and the second magnetic field.

3. The apparatus defined in claim 1 wherein the signal lines are routed around the permanent magnet so that the signal lines do not overlap the permanent magnet to minimize interactions between the static magnetic field and the second magnetic field.

4. The apparatus defined in claim 3 wherein the printed circuit comprises a flexible printed circuit.

5. The apparatus defined in claim 4 wherein the flexible printed circuit has a tail that forms a service loop.

6. The apparatus defined in claim 5 wherein the tail has a spiral shape.

7. The apparatus defined in claim 6 wherein the flexible printed circuit has a circular central portion that overlaps the permanent magnet and that is surrounded by the tail.

8. The apparatus defined in claim 7 wherein the signal lines include first and second metal traces that are coupled to the light-emitting diode and that spiral around the permanent magnet so that the first and second metal traces do not overlap the permanent magnet.

9. The apparatus defined in claim 1 wherein the signal lines include first and second metal traces that are coupled to the light-emitting diode and that spiral around the permanent magnet so that the first and second metal traces do not overlap the permanent magnet.

10. An electronic device, comprising:
a housing;
a display mounted in the housing;
a source of a first magnetic field mounted under the display;
electrical components; and
a flexible printed circuit to which the electrical components are mounted, wherein the flexible printed circuit has a tail, the flexible printed circuit overlaps the source of the first magnetic field, signal lines in the flexile printed circuit carry signals that create a second magnetic field, and the signal lines extend from the tail to the electrical components without overlapping the source of the first magnetic field to minimize vibrations in the printed circuit due to interactions between the first and second magnetic fields.

11. The electronic device defined in claim 10 wherein the flexible printed circuit tail has a curved edge.

12. The electronic device defined in claim 11 wherein the electrical components include a light-emitting diode.

13. The electronic device defined in claim 12 wherein the electrical components include a light sensor.

14. The electronic device defined in claim 11 wherein the electrical components include a pair of light-emitting diodes and a pair of light sensors.

15. The electronic device defined in claim 14 wherein the housing has a detachable portion with optical windows aligned with the pair of light-emitting diodes and the pair of light sensors, and the flexible printed circuit tail forms a service loop that allows the detachable portion to be detached while the pair of light-emitting diodes and the pair of light sensors are attached to the detachable portion.

16. The electronic device defined in claim 15 wherein the flexible printed circuit has a ground layer that overlaps the pair of light-emitting diodes and that electromagnetically shields the pair of light-emitting diodes.

17. An electronic device, comprising:
a display;
a permanent magnet that produces a static magnetic field and that is mounted under the display;
a light-emitting diode; and
a flexible printed circuit having a circular central portion that overlaps the permanent magnet so that the static magnetic field passes through the circular central portion, wherein the flexible printed circuit has a flexible tail with curved edges that surrounds the circular central portion, the light-emitting diode is mounted to the circular central portion and is coupled to signal lines in the flexible printed circuit, the signal lines carry signals that produce an induced magnetic field, and the signal lines extend from the tail to the light-emitting diode along a curved path that extends around the permanent magnet and does not overlap the permanent magnet to minimize vibrations in the printed circuit due to interactions between the first and second magnetic fields.

18. The electronic device defined in claim 17 further comprising a housing in which the display is mounted, wherein the housing has a detachable portion with a window that is aligned with the light-emitting diode and the flexible tail forms a service loop that flexes when the detachable portion is detached.

19. The electronic device defined in claim 18 wherein the electronic device further comprises a light sensor coupled to the circular central portion and ground metal traces in the circular central portion overlap and shield the light sensor.

Assignees

• Apple Inc

Inventors

• Eng Michael
• Poulain Kieran
• Mead Curtis C
• Duke Connor R

Classifications

• H01F7/20

  without armatures (cores H01F3/00; coils H01F5/00 {; shaping metal by applying magnetic forces B21D26/14; electromagnets specially adapted for NMR applications G01R33/381}) · CPC title

• H05K5/0017

  with operator interface units · CPC title

• H01F7/0252 Primary

  PM holding devices (H01F7/021, H01F7/0215, H01F7/0226 take precedence) · CPC title

• H05K2201/10106

  Light emitting diode [LED] · CPC title

• H05B47/105

  in response to determined parameters · CPC title