Integrated MEMS Accelerometer for Simultaneous Linear and Angular Sensing
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Solution Overview
Problem
Conventional MEMS accelerometers require separate devices for detecting angular and linear acceleration, leading to increased space and cost due to separate implementations on a substrate.
Innovation Solution
A single microelectromechanical system (MEMS) device is designed to detect both angular and linear acceleration using a single proof mass or multiple masses elastically connected, with tethers that respond to both types of acceleration, allowing for compact integration of angular and linear sensing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate MEMS devices are used for detecting angular and linear acceleration, then measurement precision for each type is maintained, but device complexity and space usage increase
Solution Approach 1:
The patent combines angular and linear acceleration sensing capabilities into a single MEMS device. The proof mass is elastically connected to the substrate through tethers that enable both rotational motion (for angular acceleration detection via first capacitors) and linear motion (for linear acceleration detection via second capacitors). This merging eliminates the need for separate devices while maintaining detection precision for both types of acceleration.
Solution Approach 2:
The single MEMS device performs multiple functions by detecting both angular and linear acceleration simultaneously. The proof mass structure with its tethers and capacitor arrangements enables it to respond to both rotational and linear accelerations, making one device universal for both measurement tasks rather than requiring specialized separate devices.
2Reliability
If separate MEMS devices are implemented on the substrate, then functional reliability is ensured, but area usage and manufacturing cost increase
Solution Approach 1:
The patent merges angular and linear acceleration sensing into a single integrated MEMS structure on the substrate. The shared proof mass and tether system reduces the total area required compared to two separate devices, while the distinct capacitor arrangements ensure reliable detection of both acceleration types from the same physical structure.
3Area of stationary object
If a single MEMS device detects both angular and linear acceleration, then space usage and cost are reduced, but device complexity increases
Solution Approach 1:
The single MEMS device is segmented into functionally distinct components: the proof mass, elastic tethers, first capacitors for angular sensing, and second capacitors for linear sensing. This segmentation allows the complex device to be designed and manufactured using standard MEMS fabrication processes while maintaining clear functional separation that simplifies the overall system architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a more compact and cost-effective solution that reduces space usage on a substrate while enabling simultaneous detection of angular and linear acceleration, suitable for various applications including IoT networks, wearable devices, and industrial equipment.
Implementation Method 1
a first capacitor configured to generate a first sense signal in response to rotational motion of the proof mass
Implementation Method 2
a second capacitor configured to generate a second sense signal in response to linear motion of the proof mass
Implementation Method 3
a proof mass coupled to the at least one anchor via a plurality of tethers
Data Source
AI summary
An electromechanical system (MEMS) accelerometer is described. The MEMS accelerometer may be configured to sense linear acceleration along one, two or three axes, and to sense angular acceleration about one, two or three axes. As such, the MEMS accelerometer may serve as 2-axis, 3-axis, 4-axis, 5-axis or 6-axis inertial accelerometer. In some embodiments, the MEMS accelerometer may comprise a single mass connected to at least one anchor via a plurality of tethers. In other embodiments, the MEMS accelerometer may comprise a proof mass connected to at least one anchor via a plurality of tethers and one or more shuttle masses connected to the proof mass via a second plurality of tethers. Rotational and linear motion of the MEMS accelerometer may be sensed using capacitive sensors.