Magnetic Lens Drive Layout for Low-Friction Zoom Camera Modules
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Solution Overview
Problem
Existing camera modules face challenges such as increased friction torque during zooming, lens decenter or tilt issues, size limitations for lenses, magnetic field interference, and high power consumption, particularly in ultra-slim and ultra-small designs.
Innovation Solution
A lens assembly driving apparatus with a first driving unit in the housing and a second driving unit in the lens assembly, featuring a coil and magnet configuration with specific length ratios and positioning to minimize friction and magnetic interference, while allowing for efficient zooming and optical image stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical zoom actuator is used to move the lens for zooming function, then zooming capability is achieved, but friction torque is generated causing decreased driving force, increased power consumption, and degraded control characteristics
Solution Approach 1:
The patent replaces the mechanical zoom actuator with a magnetic field-based driving system. Magnets are positioned on both the lens assembly side and housing side, creating a magnetic coupling that transmits driving force without mechanical contact. This eliminates friction torque between moving parts while maintaining zooming capability, directly resolving the contradiction between achieving zooming function and reducing power consumption.
2Loss of energy
If the separation distance between lens groups is increased to reduce friction torque, then friction resistance is reduced, but lens decenter or tilt is deepened when zoom movement is reversed
Solution Approach 1:
By replacing the mechanical contact-based driving system with a magnetic field-based system, the patent eliminates the need for large separation distances between lens groups. The magnetic coupling can transmit force through smaller gaps without requiring physical contact, thereby reducing friction torque while maintaining precise lens alignment during bidirectional zoom movements.
Solution Approach 2:
The patent employs bidirectional magnets (with different polarities) on opposite sides of the lens assembly, creating a dynamic magnetic field that can pull or push the lens group in either direction. This dynamic magnetic coupling maintains consistent separation distance while enabling smooth bidirectional movement without the decenter or tilt issues that occur with mechanical systems during reversal.
3Illumination intensity
If the lens size is increased to improve light intake, then optical performance is enhanced, but the camera module size increases contradicting ultra-slim design requirements
Solution Approach 1:
The patent divides the driving system into two separate magnetic components: one magnet assembly on the lens side and another on the housing side. This segmentation allows the lens assembly to be optimized for light intake without requiring a large single-piece mechanical actuator, enabling the lens to be larger while keeping the overall camera module compact through distributed magnetic driving components.
Solution Approach 2:
The patent positions magnets in a bidirectional configuration on opposite sides of the lens assembly, utilizing the spatial dimension behind the lens to mount driving components. This allows the front lens element to maintain its size for optimal light intake while the magnetic driving force is applied from both directions, enabling compact overall design without compromising optical performance.
4Volume of moving object
If magnets are positioned close to each other for compact design, then camera module size is reduced, but magnetic field interference occurs affecting OIS and AF operations
Solution Approach 1:
The patent applies different magnetic polarities to different regions of the magnet assemblies. The OIS magnets and AF/zoom magnets are configured with specific polarity patterns that create localized magnetic fields for their respective functions. This local differentiation of magnetic properties allows compact positioning while minimizing interference between different driving functions through strategic polarity arrangement.
Solution Approach 2:
The patent introduces magnetic yokes as intermediary components between the magnets and the lens assembly. These yokes serve as magnetic flux conduits that guide and contain the magnetic fields, preventing stray magnetic fields from interfering with adjacent components. The yokes act as magnetic shields that enable compact magnet positioning while isolating different magnetic driving functions from each other.
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 effectively reduces friction torque and prevents lens decenter or tilt, enabling the use of larger lenses for improved light intake, minimizing magnetic interference, and achieving low power consumption, thus enhancing the optical performance and usability of ultra-slim camera modules.
Implementation Method 1
A lens assembly driving apparatus according to an embodiment of the present invention comprises: a first driving unit disposed in a housing; a lens assembly disposed inside the housing; and a second driving unit disposed in the lens assembly and facing the first driving unit
Data Source
AI summary
The present embodiment relates to a lens assembly driving apparatus comprising: a first driving unit disposed in a housing; a lens assembly disposed in the housing; and a second driving unit disposed in the lens assembly and facing the first driving unit, wherein on the basis of an optical axis direction, a first length of the first driving unit is longer than or equal to a first length of the second driving unit, and on the basis of a direction perpendicular to the optical axis direction, a second length of the first driving unit is shorter than a second length of the second driving unit.