Curved Ball-Guided VCM for Optical Element Tilt Control
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Solution Overview
Problem
Current voice coil motor (VCM) actuators in digital cameras, particularly those used in smartphone cameras, face limitations in creating angular motion for optical image stabilization and extended field of view, as they primarily support linear motion, necessitating the development of a rotational ball-guided VCM that can tilt or rotate optical elements effectively.
Innovation Solution
The implementation of a rotational ball-guided VCM actuator with a curved ball-guided mechanism, where a coil and a fixed magnet are coupled to create rotation or tilt movements of optical elements around defined axes, utilizing a ferromagnetic yoke to secure the mechanism and position sensors to measure angles, allowing for precise optical path adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-guided rail is used to guide the optical element, then the motion direction is controlled, but the power consumption increases and reliability decreases during drops
Solution Approach 1:
The patent removes the spring component from the guidance mechanism, extracting the elastic element that causes both power consumption and reliability issues. The spring-guided rail is replaced with a ball-guided rail that uses rigid mechanical constraints instead of elastic springs, eliminating the continuous spring force that the motor must counteract and improving drop reliability by removing the spring's vulnerability to compression and deformation.
Solution Approach 2:
The patent substitutes the spring-based mechanical guidance system with a ball-based mechanical guidance system. The spring-guided rail uses elastic deformation to guide motion, while the ball-guided rail uses rigid geometric constraints with balls confined in grooves, replacing the elastic mechanical system with a rigid mechanical system that consumes less power and withstands drops better.
2Adaptability or versatility
If a linear ball-guided rail is used, then power consumption is reduced and reliability is improved, but angular motion capability is lost
Solution Approach 1:
The patent applies curvature to the ball-guided rail grooves, transforming the linear guidance path into an angular or rotational path. The grooves are shaped with specific curvatures that guide the balls along arc trajectories, enabling the optical element to perform angular motions such as tilting for optical image stabilization while maintaining the low power consumption and high reliability benefits of the ball-guided mechanism.
3Adaptability or versatility
If a rotational mechanism is added to enable angular motion, then optical image stabilization is achieved, but device complexity increases
Solution Approach 1:
The patent designs the ball-guided rail mechanism to serve multiple functions: it provides guidance constraints, enables rotational motion, and supports optical image stabilization capabilities. By making the guidance mechanism itself multi-functional rather than adding separate components, the patent achieves angular motion capability while minimizing the increase in device complexity. The same ball-guided structure that provides linear guidance also enables rotational motion when configured with appropriate groove curvatures.
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 efficient optical image stabilization and extended field of view capabilities by allowing precise rotational movements of optical elements, reducing power consumption and improving reliability compared to traditional spring-guided VCMs, while maintaining compact dimensions suitable for digital camera modules.
Implementation Method 1
In VCM technology, a fixed (or permanent) 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
With a ball-guided rail, the optical element 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 rotating or tilting an optical element, for example an optical path folding element, comprising a voice coil motor (VCM) and a curved ball-guided mechanism operative to create a rotation or tilt movement of the optical element around a rotation axis upon actuation by the VCM. In some embodiments, an actuator includes two, first and second VCMs, and two curved ball-guided mechanisms operative to create rotation or tilt around respective first and second rotation axes.