Magnetic Camera Actuator Structure for Low-Friction Lens Alignment
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Solution Overview
Problem
Camera modules face challenges in performing smooth zooming and autofocus functions in high magnification and heavy-weight situations, due to issues like friction torque, lens decenter, and lens tilt.
Innovation Solution
The camera actuator includes a base, a lens housing, guide pins, balls, a yoke assembly, and a coil unit, which work together to minimize friction torque and maintain lens alignment through magnetic forces and precise mechanical guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical movement is used to move the lens for zooming, then the zooming function is achieved, but friction torque is generated causing decreased driving force and increased power consumption
Solution Approach 1:
The patent replaces the traditional mechanical drive system with a magnetic drive system. The lens housing includes a magnet and coil unit that generate magnetic force to move the lens group, eliminating mechanical contact and friction torque. This substitution resolves the contradiction by achieving zooming function without the energy loss associated with mechanical friction.
2Productivity
If mechanical components are used for lens movement, then zooming is enabled, but lens decenter and tilt occur due to friction and mechanical play
Solution Approach 1:
The magnetic drive system replaces mechanical components that cause friction and play, enabling precise lens movement without contact. The magnet and coil unit provide controlled magnetic force that moves the lens group accurately, preventing decenter and tilt while maintaining optical alignment.
Solution Approach 2:
The patent introduces guide pins that extend in the optical axis direction to constrain lens movement. These guide pins prevent lateral displacement (decenter) and angular deviation (tilt) by providing geometric constraints in addition to the magnetic drive, ensuring precise lens positioning during zooming.
3Force
If separation distance is increased to reduce friction torque, then driving force improves, but lens decenter and tilt are deepened
Solution Approach 1:
The magnetic drive system eliminates the need for mechanical contact, allowing the lens housing to be separated from the base without creating friction. The magnet and coil unit generate magnetic force across the separation distance, providing driving force while the guide pins maintain lens alignment and prevent decenter and tilt.
4Productivity
If high magnification is achieved with increased stroke, then zooming capability improves, but lens decenter and tilt become more severe
Solution Approach 1:
The guide pins extend in the optical axis direction to provide constraints that prevent lateral movement and angular deviation. This geometric constraint system works in conjunction with the magnetic drive to enable large stroke for high magnification while maintaining precise lens alignment throughout the movement range.
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 enables smooth operation of zooming and autofocus functions even in high magnification and heavy-weight conditions, while preventing lens decenter and tilt, and reducing friction torque.
Implementation Method 1
a coil unit 220 surrounding a part of the first yoke and fixed to the magnet
Data Source
AI summary
The embodiment relates to a camera actuator and a camera module including the same. The camera actuator according to the embodiment includes a base, a lens housing disposed on the base, a guide pin disposed on the base, a ball disposed between the guide pin and the lens housing, and a first yoke disposed on the lens housing, a magnet coupled to an inside of the first yoke, and a coil unit facing the magnet surrounding a part of the first yoke and fixed to the magnet. The embodiment may include a second yoke disposed under the first yoke to form a closed loop together with the first yoke.