MEMS Noise Cancellation via Anti-Phase Element
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Solution Overview
Problem
Existing MEMS devices face challenges in reducing vibration and noise generated by fast-moving components, particularly in wearable devices like VR/AR headsets, as vacuum encapsulation increases size and weight, and fails to fully mitigate vibration-induced noise.
Innovation Solution
A MEMS device with a movable noise-cancelling element driven in anti-phase to counteract the noise caused by the oscillation of the movable MEMS element, using a controller to synchronize electrical signals with the actuator and noise-cancelling element, often formed on a common semiconductor substrate for efficient coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If vacuum encapsulation is used to reduce noise from MEMS elements, then noise reduction is improved, but device size and weight increase
Solution Approach 1:
The patent extracts the noise-generating function from the MEMS element by introducing a separate noise-cancelling element that produces anti-phase noise. This allows the main MEMS element to be removed from vacuum encapsulation, reducing device size and weight while still achieving noise reduction through the extracted noise-cancellation mechanism.
Solution Approach 2:
The patent introduces a noise-cancelling element as an intermediary component that mediates between the MEMS element and the external environment. This intermediary generates anti-phase noise to cancel the harmful noise from the MEMS element, achieving noise reduction without requiring vacuum encapsulation of the main functional component.
2Object-affected harmful factors
If vacuum encapsulation is used to reduce noise from MEMS elements, then noise reduction is improved, but device complexity increases
Solution Approach 1:
The patent extracts the noise-cancellation function into a separate element rather than incorporating it into the vacuum encapsulation structure. This separation simplifies the overall device architecture by eliminating the need for complex vacuum sealing while maintaining noise reduction through the independent noise-cancelling element.
3Object-affected harmful factors
If vacuum encapsulation is used to reduce audible noise, then audible noise is reduced, but vibration is mechanically coupled to external parts creating noise
Solution Approach 1:
The patent introduces a noise-cancelling element as an intermediary that directly addresses the vibration source by generating anti-phase vibrations. This intermediary approach cancels both the audible noise and the mechanically coupled vibrations at their source, preventing them from being transmitted to external parts without requiring vacuum encapsulation.
Solution Approach 2:
The patent converts the harmful vibration and noise generated by the MEMS element into a beneficial cancellation mechanism. By driving the noise-cancelling element in anti-phase, the harmful vibrations are transformed into constructive interference that eliminates the original noise and vibration problems.
4Object-affected harmful factors
If a noise-cancelling element is added to cancel MEMS noise, then noise cancellation is improved, but device complexity increases
Solution Approach 1:
The patent merges the noise-cancelling element with the actuator structure, allowing both components to share a common mounting substrate and control system. This integration reduces device complexity by combining multiple functions into a unified structure rather than adding separate independent components.
Solution Approach 2:
The patent designs the noise-cancelling element to serve multiple functions: it generates anti-phase noise for cancellation, shares the actuator mounting substrate for structural support, and can be controlled through the existing controller system. This multi-functionality reduces overall device complexity despite adding noise-cancellation capability.
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
Effectively cancels noise and vibration, enhancing user experience by reducing disturbance in wearable devices without the drawbacks of increased size and weight, while maintaining compactness and efficiency.
Implementation Method 1
a movable noise-cancelling element arranged to be driven under the control of the controller to produce anti-phase noise to cancel noise caused by oscillation of the movable MEMS element
Data Source
AI summary
There is provided a micro-electromechanical system (MEMS) device (102, 200, 300, 404) for cancelling noise generated by oscillation of a movable micro-electromechanical system (MEMS) element (104, 204, 304, 406). The micro-electromechanical system (MEMS) device (102, 200, 300, 404) includes the movable micro-electromechanical system (MEMS) element (104, 204, 304, 406), an actuator (106, 208, 306, 408), a controller (108, 410) and a movable noise cancelling element (110, 202, 312, 412). The controller (108, 410) provides electrical signals to drive the actuator (106, 208, 306, 408) and the movable noise cancelling element (110, 202, 312, 412) in a way to cancel the noise generated in the micro-electromechanical system (MEMS) device (102, 200, 300, 404) by oscillation of the movable MEMS element (104, 204, 304, 406). The movable noise-cancelling element (110, 202, 312, 412) produces anti-phase noise based on the electrical signals received from the controller (108, 410) to cancel noise caused by oscillation of the movable MEMS element (104, 204, 304, 406) based on the control signals received from the controller (108, 410).