Ball-Guided Folded-Optic Voice Coil Motor for Compact Focus and OIS
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Solution Overview
Problem
Existing voice coil motor (VCM) actuators for digital cameras, particularly in folded camera structures, face challenges in reducing camera dimensions, especially height and width, while providing effective actuation mechanisms for optical elements.
Innovation Solution
The implementation of linear ball-guided rails in VCM actuators for digital cameras, allowing for two-directional movement of lens holders, utilizing a first VCM engine for focus and a second VCM engine for optical image stabilization, with ball-guided rails to minimize power consumption and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring-guided rails are used in VCM actuators, then the motion direction of the lens is controlled, but the power consumption increases due to the need to oppose spring mechanical force
Solution Approach 1:
The patent replaces the spring-guided mechanical system with a ball-guided rail system. The ball-guided rail uses rolling balls in grooves to guide lens motion, eliminating the need for spring forces. This substitution maintains reliable motion direction control while significantly reducing power consumption, as the magnetic force no longer needs to overcome spring mechanical force.
Solution Approach 2:
The patent segments the guidance function from the actuation function. The ball-guided rail provides pure mechanical guidance through grooves and balls, while the voice coil motor provides actuation force independently. This segmentation allows the magnetic force to act freely without opposing spring forces, reducing power consumption while maintaining motion control reliability.
2Adaptability or versatility
If the camera module includes focus and OIS mechanisms, then the optical functions are advanced, but the camera dimensions (height and width) increase
Solution Approach 1:
The patent merges the focus actuation and OIS actuation into a single integrated VCM actuator assembly. Both the lens holder (for focus) and the optical path folding element (for OIS) are actuated by voice coil motors within the same compact structure. This merging allows both advanced optical functions to coexist in a space-efficient manner, reducing overall camera dimensions.
Solution Approach 2:
The patent introduces an optical path folding element that redirects the optical path at an angle, effectively using three-dimensional space more efficiently. By folding the optical path rather than extending it linearly, the camera module achieves advanced optical functions without proportionally increasing camera dimensions, particularly in the height direction.
3Use of energy by moving object
If ball-guided rails are used instead of spring-guided rails, then power consumption is reduced, but the complexity of the mechanical structure increases
Solution Approach 1:
The patent extracts the spring elements from the guidance system and replaces them with a pure ball-guided rail structure. The grooves and balls provide guidance functionality without requiring springs, simplifying the mechanical structure while reducing power consumption. The unnecessary spring components are removed, leaving only the essential ball-guided rail mechanism.
4Adaptability or versatility
If the lens holder moves in multiple directions for focus and OIS, then the actuation capabilities are improved, but the reliability decreases due to potential deviation from desired motion path
Solution Approach 1:
The patent introduces ball-guided rails as intermediary elements between the actuation forces and the lens holder. The grooves in the rails act as mediators that constrain and guide the lens holder motion along precise paths. This intermediary guidance system ensures that multi-directional actuation capabilities are achieved while maintaining reliable motion path accuracy, preventing deviation during focus and OIS operations.
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 reduced camera dimensions and improved actuation capabilities for autofocus and optical image stabilization, enhancing reliability and reducing power consumption.
Implementation Method 1
In VCM technology, a permanent (or 'fixed') magnet and a coil are used to create actuation force. The coil is positioned in the vicinity of the magnetic field of the fixed magnet. Upon driving current in the coil, a Lorentz force is created on the coil, an in return an equal counter-force is applied on the magnet.
Implementation Method 2
Another typical mechanical rail is known in the art a 'ball-guided rail', see e.g. U.S. Pat. No. 8,810,714. With a ball-guided rail, the lens is bound to move in the desired direction by set of balls confined in a groove (also referred to as 'slit').
Data Source
AI summary
Actuators for carrying and actuating a lens having a first optical axis, the lens receiving light folded from a second optical axis substantially perpendicular to the first optical axis, comprising first and second VCM engines coupled to the lens and first and second linear ball-guided rails operative to create movement of the lens in two substantially orthogonal directions upon actuation by respective VCM engines.