Camera Actuator Guide Pin and Ball Layout for Lens Centering
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Solution Overview
Problem
Camera modules face challenges in performing smooth zooming and autofocus functions at high magnification and heavy weight situations due to friction torque, lens decenter, and lens tilt issues, which affect image quality and resolution.
Innovation Solution
A camera actuator design featuring a base, lens housing, guide pins, balls, a yoke assembly, and a coil unit with magnets that generate magnetic forces to stabilize and drive the lens, ensuring four-point contact and centering of the lens housing to minimize friction and tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the separation distance in the friction area is increased to reduce friction torque resistance during lens movement, then friction torque is reduced, but lens decent or lens tilt is deepened when zoom movement is performed or reversed
Solution Approach 1:
A guide pin is introduced as an intermediary component between the lens holder and the friction reduction mechanism. The guide pin has a cylindrical shape that fits into a guide hole, providing mechanical guidance and constraint to prevent lens decent and tilt while allowing the friction torque reduction mechanism to operate effectively. This mediator resolves the contradiction by decoupling the functions of friction reduction and alignment maintenance.
Solution Approach 2:
The lens driving mechanism is segmented into multiple functional components: a lens holder for holding the lens, a friction reduction mechanism (such as a magnetic levitation system or air bearing) for reducing friction torque, and a guide pin for maintaining alignment. This segmentation allows each component to specialize in one function, resolving the contradiction between friction reduction and alignment precision.
2Length of moving object
If high magnification is required in the camera module, then the stroke increases, but the lens decent or lens tilt becomes more severe in high magnification situations
Solution Approach 1:
The guide pin acts as a mediator that provides continuous mechanical guidance throughout the entire stroke length. Its cylindrical geometry constrained within a guide hole ensures that even during large displacement movements required for high magnification, the lens remains properly aligned without decent or tilt.
Solution Approach 2:
The guide pin constraint operates in a dimensional sense by providing guidance in radial directions (preventing decent and tilt) while allowing freedom of movement in the axial direction (enabling long stroke). This dimensional separation resolves the contradiction between long stroke and alignment precision.
3Length of moving object
If the weight of the camera module increases for high magnification, then the movement becomes more difficult, but friction torque increases further
Solution Approach 1:
The friction reduction mechanism replaces traditional mechanical contact-based driving with a non-contact or minimal-contact system such as magnetic levitation or air bearing. This substitution eliminates or significantly reduces friction torque, making it feasible to move heavier lens assemblies required for high magnification without excessive friction resistance.
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 smooth operation of zooming and autofocus functions in high magnification and heavy weight conditions by reducing friction torque and preventing lens decenter or tilt, thereby maintaining image quality and resolution.
Implementation Method 1
a coil unit 220 surrounding a part of the first yoke and fixed to the magnet
Implementation Method 2
a ball 70 disposed between the guide pin and the lens housing
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.