Camera Actuator Comb Drive Assembly for Miniaturized Autofocus
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Solution Overview
Problem
Current autofocus technologies in miniature cameras, such as voice coil motors, face challenges with high power consumption and low force relative to the size, necessitating advancements for improved performance and miniaturization while maintaining high image quality.
Innovation Solution
The implementation of a camera actuator assembly using comb drive actuators with mechanical flexures, allowing for six degrees of freedom movement of the image sensor relative to the lens, enabling precise positioning and stabilization, which is achieved through a combination of electrostatic comb-drive actuators and flexible mechanical connections on a ceramic substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If voice coil motor is used for autofocus, then the camera can achieve focus adjustment, but power consumption is high and relative force is low
Solution Approach 1:
The patent replaces the voice coil motor (electromagnetic system) with a comb drive actuator system that uses electrostatic forces. This substitution eliminates the need for continuous electromagnetic field generation, significantly reducing power consumption while maintaining focus adjustment capability through precise electrostatic actuation of the comb drive fingers.
Solution Approach 2:
The patent changes the operating parameters from electromagnetic (voice coil) to electrostatic (comb drive). The comb drive actuator operates at lower voltages with pulsed signaling, changing the energy consumption profile from continuous high power to intermittent low power, thereby resolving the power consumption issue while preserving focus functionality.
2Volume of moving object
If camera components are miniaturized, then device size is reduced, but performance and image quality may deteriorate
Solution Approach 1:
The patent transitions from one-dimensional linear actuators to a two-dimensional comb drive structure with multiple interdigitated fingers. This dimensional change allows the actuator to generate higher forces in a compact footprint, enabling miniaturization without sacrificing performance. The multi-finger comb drive provides both compact size and sufficient actuation force for high-quality image stabilization.
Solution Approach 2:
The patent divides the actuator into multiple comb drive fingers that can be independently controlled. This segmentation allows for finer resolution in position control and enables the system to achieve high manufacturing precision through coordinated actuation of individual fingers, maintaining image quality even in miniaturized form factors.
3Stability of the object's composition
If comb drive actuators are rigidly affixed to the base substrate, then structural stability is improved, but motion control flexibility is reduced
Solution Approach 1:
The patent employs a hybrid mounting strategy where comb drive actuators are rigidly affixed to the base substrate for structural stability, while the image sensor platform is flexibly connected through mechanical flexures. This dynamic design allows the rigid comb drives to provide stable actuation forces while the flexible flexures enable multi-degree-of-freedom motion control, resolving the contradiction between stability and flexibility.
Solution Approach 2:
The patent introduces mechanical flexures as intermediary elements between the rigid base substrate and the movable image sensor platform. These flexures act as mediators that transmit actuation forces from the rigidly mounted comb drives while allowing flexible multi-axis motion, thereby maintaining both structural stability and motion control versatility.
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 solution enhances the performance of miniature cameras by reducing power consumption, enabling compact designs, and improving image quality by allowing for precise control of the image sensor's position and orientation, thus addressing the limitations of existing technologies.
Implementation Method 1
a plurality of comb drive actuators rigidly affixed to the first portion of the base substrate... arranged to control the motion of the second portion
Implementation Method 2
the plurality of comb drive actuators is flexibly affixed to the second portion of the base substrate by a plurality of respective mechanical flexures
Data Source
AI summary
Some embodiments include an actuator assembly for mounting a moving component. In some embodiments, the actuator assembly includes a base substrate including a first portion for mounting comb drive actuators and a second portion for mounting the moving component. In some embodiments, the actuator assembly includes a plurality of comb drive actuators rigidly affixed to the first portion of the base substrate. In some embodiments, the plurality of comb drive actuators is flexibly affixed to the second portion of the base substrate by a plurality of respective mechanical flexures. In some embodiments, the respective mechanical flexures provide a flexible mechanical connection between the second portion and the first portion, and the plurality of comb drive actuators is arranged to control the motion of the second portion to adjust the position of the moving component in multiple degrees of freedom relative to first portion.