Substrate curvature compensation methods and apparatus

摘要

A method for providing acceleration data with reduced substrate-displacement bias includes receiving in an accelerometer an external acceleration, determining the acceleration data with reduced substrate displacement bias in a compensation portion in response to a first and a second displacement indicators from a MEMS transducer, and, in response to substrate compensation factors from a MEMS compensation portion, outputting the acceleration data with reduced substrate displacement bias, wherein the first displacement indicator and the second displacement indicator are determined by the MEMS transducer relative to a substrate in response to the external acceleration and to a substrate displacement, and wherein the substrate compensation factors are determined by the MEMS compensation portion relative to the substrate in response to the substrate displacement.

主权项

1. A method for providing acceleration data, with reduced substrate-displacement bias, from an accelerometer comprising
a substrate, an asymmetrically weighted MEMS transducer disposed on the substrate, the MEMS transducer having a first transducer portion, a second transducer portion, and a transducer axis of rotation, wherein the first transducer portion is longer than the second transducer portion, at least one symmetrically weighted MEMS compensation structure disposed on the substrate, the MEMS compensation structure having a first compensation portion, a second compensation portion, and a compensation axis of rotation, wherein the first compensation portion and the second compensation portion are equal in length, wherein the MEMS compensation structure is configured such that the compensation axis of rotation is coincident with the transducer axis of rotation, and a compensation circuit disposed on the substrate, the compensation circuit being coupled to the MEMS transducer and the MEMS compensation structure, wherein the substrate is subject to a substrate displacement, the method comprising: receiving in the accelerometer an external acceleration; determining the acceleration data with reduced substrate displacement bias in the compensation circuit in response to a first displacement indicator and a second displacement indicator from the MEMS transducer and in response to substrate compensation factors from the MEMS compensation structure; and outputting the acceleration data with reduced substrate displacement bias from the compensation circuit; wherein the first displacement indicator and the second displacement indicator are determined by the MEMS transducer relative to the substrate in response to the external acceleration and to the substrate displacement; and wherein the substrate compensation factors are determined by the MEMS compensation structure relative to the substrate in response to the substrate displacement.