Electronic Device With Printed Circuit Board Stress Monitoring

• US 20140331741A1
• Filed: 05/13/2013
• Published: 11/13/2014
• Est. Priority Date: 05/13/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Shah, Dhaval N., Malek, Shayan, Katiyar, Vivek
• Granted Patent: US 9,080,932 B2
• Time in Patent Office: Days
• US Class Current: 73/12.06
• CPC Class Codes: G01L 1/2262 involving simple electrical bridges
• CPC Class Codes: G01L 1/2287 constructional details of the strain gauges adjustable resistors H01C10/00
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 99/00 Subject matter not provided for in other groups of this subclass
• CPC Class Codes: G01N 2033/0078 testing material properties on manufactured objects
• CPC Class Codes: G01N 3/30 by applying a single impulsive force, e.g. by falling weight
• CPC Class Codes: G01N 3/303 generated only by free-falling weight
• CPC Class Codes: G01P 15/0891 with indication of predetermined acceleration values G01P15/135 takes precedence
• CPC Class Codes: G06F 1/1633 Constructional details or arrangements of portable computers not specific to the type of enclosures covered by groups G06F1/1615 - G06F1/1626
• CPC Class Codes: H04M 1/0277 for a printed circuit board assembly
• CPC Class Codes: H04M 1/185 Improving the rigidity of the casing or resistance to shocks
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion telephones including GPS signal receivers H04M2250/10

Abstract

An electronic device may contain electrical components mounted on one or more substrates such as printed circuit boards. During a drop event, the printed circuit boards and components may be subjected to stresses. Strain gauges may be formed from metal traces embedded within dielectric layers in the printed circuit boards. The strain gauges may be used to make stress measurements at various locations on the boards. Stress data may be collected in response to data from an accelerometer indicating that the device has been dropped. Stress data collection may be halted in response to determining that the device has struck an external surface. Impact may be detected using accelerometer data, strain gauge output, or other sensor data. Stress data may be analyzed by the electronic device or external equipment.

Claims

1. An electronic device, comprising:

an accelerometer;

storage; and

circuitry that is configured to detect whether the electronic device has been dropped based on data from the accelerometer and, in response to determining that the electronic device has been dropped, storing data in the storage.

2. The electronic device defined in claim 1 wherein the data comprises stress data and wherein the electronic device further comprise at least one strain gauge that generates the stress data.

3. The electronic device defined in claim 2 further comprising a printed circuit board, wherein the strain gauge comprises metal traces supported by the printed circuit board.

4. The electronic device defined in claim 3 wherein the printed circuit board comprises multiple dielectric layers and wherein the metal traces comprise a meandering trace embedded within the dielectric layers.

5. The electronic device defined in claim 1 wherein the data comprises stress data and wherein the electronic device comprises a plurality of strain gauges that generate the stress data.

6. The electronic device defined in claim 5 further comprising a printed circuit board having dielectric layers, wherein the plurality of strain gauges are sandwiched between the dielectric layers.

7. The electronic device defined in claim 2 wherein the storage comprises a circular buffer, wherein the circuitry is configured to collect the stress data in the circular buffer.

8. The electronic device defined in claim 7 wherein the circuitry is configured to halt collection of the stress data in the circular buffer.

9. The electronic device defined in claim 7 wherein the circuitry is configured to detect when the electronic device has impacted an external surface and wherein the circuitry is configured to halt collection of the stress data in the circular buffer in response to determining that the electronic device has impacted the external surface.

10. A method of gathering information on operation of an electronic device by a user, comprising:

with an accelerometer in the electronic device, monitoring the electronic device to determine whether the electronic device has been dropped;

in response to determining that the electronic device has been dropped, collecting stress data in the electronic device.

11. The method defined in claim 10 wherein the electronic device comprises a printed circuit board with dielectric layers and wherein collecting the stress data comprises:

collecting the stress data with at least one strain gauge sensor embedded between the dielectric layers.

12. The method defined in claim 10 wherein the electronic device comprises a printed circuit board with dielectric layers and wherein collecting the stress data comprises:

collecting the stress data with a plurality of strain gauge sensors embedded within the dielectric layers.

13. The method defined in claim 12 further comprising collecting the stress data in storage in the electronic device.

14. The method in claim 13 further comprising:

determining whether the electronic device has struck an external surface; and

halting the collection of the stress data in response to determining that the electronic device has struck the external surface.

15. The method defined in claim 14 wherein determining whether the electronic device has struck the external surface comprises determining whether data from the accelerometer has exceeded a predetermined threshold.

16. The method defined in claim 14 wherein determining whether the electronic device has struck the external surface comprises determining whether the stress data has exceeded a predetermined threshold.

17. The method defined in claim 10 further comprising:

providing the collected stress data to external equipment over a communications path.

18. A portable electronic device, comprising:

a housing;

a printed circuit board in the housing;

electrical components mounted on the printed circuit board; and

a strain gauge embedded in the printed circuit board.

19. The portable electronic device defined in claim 18 further comprising:

circuitry that collects stress data from the strain gauge.

20. The portable electronic device defined in claim 19 further comprising:

an accelerometer, wherein the circuitry is configured to initiate collection of the stress data in response to data from the accelerometer and wherein the circuitry is configured to halt collection of the stress data in response to data indicative of an impact between the portable electronic device and an external surface.