Camera Actuator Yoke Structure for Lens Alignment During Zooming
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Solution Overview
Problem
Existing camera modules face challenges in maintaining precise alignment between lens groups during zooming and auto focusing, which can lead to image quality issues due to frictional torque and increased probability of decentering or tilting.
Innovation Solution
A camera module design that includes a lens group, a lens support unit, a magnet, a yoke part, and a coil, where the lens group, lens support unit, and magnet move along the optical axis with a current applied to the coil, utilizing a yoke structure with different permeability layers to manage magnetic forces and reduce frictional torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a lens moves for a zooming function in a camera module, then the zooming function is achieved, but frictional torque is generated causing decrease in driving force, increase in power consumption, or degradation of control characteristics
Solution Approach 1:
The patent replaces traditional mechanical zooming mechanisms with an electromagnetic driving unit consisting of a coil, magnet, and yoke. This substitution eliminates mechanical friction and contact wear, reducing power consumption and improving control characteristics while maintaining the zooming function. The electromagnetic field directly actuates the lens group without mechanical friction.
Solution Approach 2:
The patent optimizes the separation distance between the coil and magnet as a key parameter to minimize frictional torque and electromagnetic resistance. By adjusting this distance within a specific range, the system achieves efficient electromagnetic actuation with reduced power consumption and improved driving force for the zooming function.
2Loss of energy
If a separation distance is increased in a movement area to reduce frictional torque, then frictional torque is reduced, but a probability of occurrence of decentering or tilting increases
Solution Approach 1:
The patent introduces a yoke structure as an intermediary component between the electromagnetic driving unit and the lens support unit. The yoke provides precise geometric constraints and guidance for the lens group movement, ensuring accurate alignment and preventing decentering or tilting even when the coil-magnet separation distance is increased to reduce frictional torque.
Solution Approach 2:
The patent replaces traditional mechanical guidance structures with a combined electromagnetic-yoke system. The yoke provides precise mechanical guidance and alignment constraints while the electromagnetic field provides the driving force, achieving both reduced friction and maintained alignment precision simultaneously.
3Ease of operation
If decentering occurs in which a center of a spherical surface between the lens groups deviates from an optical axis, then alignment is lost, but a tilting phenomenon occurs in which a lens is tilted, or central axes of the lens groups and the image sensor are not aligned
Solution Approach 1:
The yoke acts as a precision intermediary structure that mechanically constrains the lens group to move along the optical axis without decentering or tilting. The geometric design of the yoke ensures that the lens group maintains proper alignment with the image sensor throughout the zooming range, preventing image quality degradation.
Solution Approach 2:
The patent incorporates a sensor that detects the position of the lens group and provides feedback to the control system. This feedback mechanism enables real-time correction of any decentering or tilting, ensuring maintained alignment and consistent image quality throughout operation.
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 precise zooming and auto focusing while maintaining alignment between lens groups, improving image quality and reducing power consumption by minimizing frictional torque and controlling magnetic forces effectively.
Implementation Method 1
all the lens group, the lens support unit, and the magnet move along an optical axis according to a current applied to the coil
Implementation Method 2
the yoke part includes a first yoke and a second yoke disposed on the first yoke, the second yoke is disposed between the first yoke and the coil, and magnetism of the first yoke is stronger than magnetism of the second yoke
Implementation Method 3
An attractive force may act between the magnet and the yoke part, and a repulsive force may act between the first yoke and the second yoke
Data Source
AI summary
A camera module according to an embodiment of the present invention includes: a lens group; a lens support unit for accommodating the lens group; a magnet arranged on the outer surface of the lens support unit; a yoke portion spaced apart from the magnet and arranged to face the magnet; and a coil arranged on the yoke portion so as to be spaced apart from and to face the magnet between the magnet and the yoke portion, wherein the lens group, the lens support unit, and the magnet move together along an optical axis according to a current applied to the coil, the yoke portion includes a first yoke and a second yoke arranged on the first yoke, the second yoke is arranged between the first yoke and the coil, and magnetism of the first yoke is stronger than that of the second yoke.