Nested 5-DOF MEMS Actuator for Decoupled Camera Lens Motion
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Solution Overview
Problem
Existing MEMS electrostatic actuators for miniature cameras lack the ability to provide fully decoupled motion along the x, y, and z axes, limiting their functionality in achieving autofocus, optical image stabilization, and super resolution imaging.
Innovation Solution
A 5-DOF electrostatic microactuator with nested MEMS structures that provide translation motions along the x, y, and z axes, and bi-axial tilt about the x and y axes, utilizing compliant and highly stiff mechanical springs to achieve total decoupling between axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional actuators are used for autofocus and optical image stabilization, then the camera module size is reduced, but the actuators cannot provide both autofocus and optical image stabilization functions simultaneously
Solution Approach 1:
The patent applies multi-functionality by designing a single actuator that performs both autofocus (axial movement) and optical image stabilization (lateral movement) functions. The actuator includes a movable stator assembly with multiple stators arranged around a rotor, where electrostatic forces between stators and the rotor enable both axial and lateral movements of the lens barrel, eliminating the need for separate actuators for each function.
Solution Approach 2:
The patent applies nesting by placing the movable stator assembly inside the stationary stator housing, with the rotor nested within the movable stator assembly. This nested configuration allows multiple functional components to be integrated in a compact arrangement, enabling both autofocus and optical image stabilization functions within a single actuator structure without increasing overall device size.
2Reliability
If multiple separate actuators are used for autofocus and optical image stabilization, then each function can be independently optimized, but the overall device size and complexity increase
Solution Approach 1:
The patent applies merging by combining the autofocus actuator and optical image stabilization actuator into a single integrated unit. The movable stator assembly with multiple stators and the shared rotor enable both axial (autofocus) and lateral (OIS) movements through coordinated electrostatic forces, reducing the total volume compared to using separate actuators while maintaining functional independence through controlled activation of different stator pairs.
3Volume of moving object
If a single actuator provides both autofocus and optical image stabilization, then device size is reduced, but the actuator must handle complex multi-directional motions
Solution Approach 1:
The patent applies segmentation by dividing the stator assembly into multiple discrete stators (first, second, third, and fourth stators) arranged around the rotor. Each stator can be independently controlled to generate electrostatic forces in specific directions, enabling precise control over axial and lateral movements. This segmented structure simplifies motion control by allowing independent activation of stator pairs for different motion modes (autofocus vs. OIS).
Solution Approach 2:
The patent applies dynamics by using electrostatic forces between charged stators and the rotor to create controllable, dynamic movements. The movable stator assembly can dynamically adjust its position and orientation by varying the electrostatic forces applied to different stator pairs, enabling smooth transitions between autofocus and optical image stabilization modes while handling complex multi-directional motions efficiently.
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
Enables simultaneous and efficient autofocus, optical image stabilization, and super resolution imaging by providing fully decoupled motions, enhancing camera performance and robustness against shock forces.
Implementation Method 1
A MEMS electrostatic actuator that provides 5 degrees of freedom (5-DOF) motion is disclosed. The rotors further comprise a plurality of moving capacitive electrodes which engage with a plurality of fixed capacitive electrodes in the stators to provide a variety of translational and rotational motions.
Data Source
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AI summary
A MEMS electrostatic actuator that provides 5 degrees of freedom (5-DOF) motion is disclosed. The actuator comprises of an inner, a middle, and an outer MEMS structures that are nested with respect to each other. Each of the structures comprise of a plurality of rotors and stators. The rotors further comprise a plurality of moving capacitive electrodes which engage with a plurality of fixed capacitive electrodes in the stators to provide a variety of translational and rotational motions.