Piezoelectric Actuator Arm for Large Deflection
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Solution Overview
Problem
Existing microelectromechanical systems (MEMS) scanning micro-mirrors face challenges in achieving large deflection angles without applying high voltages or compromising device accuracy and robustness.
Innovation Solution
A piezoelectric actuating device with a thin membrane actuator arm, having a width at least ten times its thickness, allows for robust and large deflections by utilizing the inverse piezoelectric effect to deform the actuator arm, which moves a connected moveable element, with independently addressable segments for precise control and a curved design to avoid weak spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If high voltages are applied to achieve large deflection angles, then the deflection angle is improved, but the accuracy and robustness of the device deteriorates
Solution Approach 1:
The patent changes the geometric parameters of the actuator arm, specifically making the width at least ten times the thickness. This parameter change allows the structure to achieve large deflections through its design rather than requiring high voltages, thereby maintaining accuracy and robustness while improving deflection angle
Solution Approach 2:
The actuator arm is designed with a curved shape rather than a straight configuration. This curvature allows the arm to accumulate deflection along its length while maintaining structural integrity, enabling large deflection angles without compromising robustness or requiring high voltages
2Length of moving object
If the actuator arm is made thin to allow large deflections, then the deflection capability is improved, but the strength and robustness of the device deteriorates
Solution Approach 1:
The patent transitions from considering only the thickness dimension to utilizing the width dimension extensively. By making the width at least ten times the thickness, the actuator arm gains structural strength in the width direction while maintaining flexibility for deflection, effectively using dimensional change to resolve the strength-deflection trade-off
Solution Approach 2:
The actuator arm is designed as a thin membrane structure with width at least ten times thickness. This thin film configuration provides flexibility for large deflections while the extensive width provides sufficient strength and robustness, preventing the structure from being too weak to survive operation
3Device complexity
If straight and narrow actuator arms are used, then the device complexity is reduced, but weak spots are created that reduce reliability
Solution Approach 1:
The patent replaces straight actuator arms with curved configurations. This curvature eliminates the weak spots that occur at edges and corners of straight arms by distributing stress more evenly throughout the structure, improving reliability without significantly increasing device complexity
Solution Approach 2:
The actuator arm design uses asymmetric curvature rather than symmetric straight lines. This asymmetric curved shape optimizes the distribution of mechanical stress and eliminates concentrated weak spots, improving the overall reliability of the device
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 high angular movement and stable static deflection, achieving optical deflection angles of 25° to 30° for a 3 mm mirror, and allows for a wide range of optical technologies applications with increased robustness and control over the moveable element.
Implementation Method 1
when the piezoelectric arm is actuated, i.e. a voltage is applied, an inverse piezoelectric effect results in a dimensional change and/or a deformation of the membrane
Data Source
AI summary
An actuating device and projection and imaging systems using said actuating device are provided. The actuating device includes at least one actuator arm having a piezoelectric membrane. The actuator arm has a width at least ten times its thickness. The actuating device also includes a moveable element, connected to the actuator arm, such that actuation of the actuator arm causes movement of the moveable element.