Piezoelectric MEMS Mirror Scanner With Lever-Amplified Rotation
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Solution Overview
Problem
Existing MEMS scanners face challenges in achieving precise and controlled rotational displacement of mirror devices due to assembly variations and limited robustness, particularly in non-resonant systems.
Innovation Solution
A non-resonant MEMS scanning device utilizing piezoelectric actuation principles with a torsional beam structure and actuator wings, where the actuators are coupled to the torsional beam via a two-stage lever device, allowing for controlled torsional force application and rotation about a longitudinal axis, and incorporating sensing elements for precise rotation detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If piezoelectric actuators are used to actuate the mirror device, then manufacturing precision and assembly robustness are improved, but the rotational displacement magnitude is limited by the actuator size
Solution Approach 1:
A lever device is introduced as an intermediary mechanism between the piezoelectric actuators and the mirror device. The lever device amplifies the rotational displacement generated by the actuators while maintaining the precision and robustness benefits of piezoelectric actuation. This mediator allows small actuator displacements to be transformed into larger mirror rotations.
Solution Approach 2:
The patent employs a torsional beam structure that converts linear actuator displacement into rotational motion of the mirror device. By changing the dimension of motion from linear (actuator expansion/contraction) to rotational (mirror scanning), the system achieves larger effective displacement while maintaining actuator compactness.
2Length of moving object
If a torsional beam structure with lever device is used, then rotational displacement is amplified beyond actuator displacement, but device complexity increases
Solution Approach 1:
The actuator assembly is segmented into distinct functional components: piezoelectric actuators, lever devices, and torsional beam structures. This segmentation allows each component to be optimized independently and facilitates modular assembly, reducing overall system complexity despite the amplified displacement capability.
Solution Approach 2:
The lever device and torsional beam structure create a dynamic mechanical advantage system that amplifies displacement only when needed during actuation. The structure transitions between static and dynamic states, providing complexity only during operation while maintaining structural integrity at rest.
3Measurement precision
If multiple actuators are used on opposite sides of the mirror device, then control precision and stability are improved, but manufacturing complexity increases
Solution Approach 1:
While the overall configuration uses symmetry for stability, the patent incorporates asymmetric elements in the actuator and lever design that simplify manufacturing. The asymmetric geometry allows for optimized stress distribution and easier fabrication of individual components, reducing cumulative manufacturing complexity despite multiple actuators.
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
The solution enables controlled and predictable rotational displacement of the mirror device, exceeding the rotational displacement of individual actuators, with improved robustness and reliability, facilitating precise scanning applications.
Implementation Method 1
Each piezoelectric actuator may include a silicon substrate having a thin film piezoelectric material deposited thereon
Data Source
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AI summary
The present disclosure relates to a microelectromechanical systems (MEMS) scanner that implements piezoelectric actuation principles to facilitate rotational displacement of a mirror device. The present disclosure includes a MEMS scanning device having a mirror device, a torsional beam structure, and piezoelectric actuators having a shape that facilitates torsional force to be applied to the torsional beam structure and cause the mirror device to rotate about a longitudinal axis. The MEMS scanning device may further include a lever device including multiple stages to both transfer torsional force from the actuators and prevent different actuators from countering torsional forces of other actuators. Moreover, the MEMS scanning device may further include sensor elements to measure torsional forces and control movement of the mirror device.