The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 29, 2022
Filed:
Sep. 27, 2018
Apple Inc., Cupertino, CA (US);
Wesley S. Smith, Mountain View, CA (US);
Christopher C. Painter, Dublin, CA (US);
See-Ho Tsang, Cupertino, CA (US);
Apple Inc., Cupertino, CA (US);
Abstract
An in-situ test calibration system and method are disclosed where a perpetual out-of-band electrostatic force induced excitation is used to dither the proof-mass of a MEMS based accelerometer where the amount of deflection change is proportional to sensitivity changes. The supplier of the accelerometer would exercise the accelerometer in a calibration station to determine initial sensitivity values. After the calibration and before removing the accelerometer from the calibration station, the supplier would start the dither and calibrate the acceleration equivalent force (F) to drive voltage transfer function (F/V). After installation of the accelerometer into a system or sometime later in the field, any changes in the F/V transfer function due to changes in the sensitivity are observable and can be used for re-calibrating the accelerometer.