Image Sensor Shift Actuator with Yoke-Based Position Sensing
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Solution Overview
Problem
The increasing weight of lens modules in camera modules, combined with the weight of driving units, makes it difficult to precisely control the driving force for shake correction, and the use of Hall sensors complicates the control configuration and increases costs.
Innovation Solution
A sensor shifting actuator with a first movable body housing an image sensor, a fixed body allowing movement in two directions parallel to the imaging surface, a driving unit providing a driving force, and a position sensing unit using a sensing coil and a sensing yoke unit with multiple spaced sensing yokes that change width in the moving direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall sensors are used to sense the position of the lens module, then the position determination accuracy is improved, but the control configuration becomes complicated and the unit cost increases
Solution Approach 1:
The patent replaces the Hall sensor-based magnetic detection system with a mechanical sensing system using a sensing yoke and scale pattern. The sensing yoke mechanically follows the scale pattern on the movable body, converting position information through mechanical interaction rather than magnetic field detection. This substitution simplifies the control configuration while maintaining measurement precision.
Solution Approach 2:
The patent uses a scale pattern that is copied or replicated on the movable body, which the sensing yoke then reads through mechanical contact. This copying approach allows position detection without complex electronic sensors, reducing both configuration complexity and cost while preserving accuracy.
2Measurement precision
If the number of Hall sensors is increased, then the accuracy of position determination is improved, but the unit cost increases and there is a limitation in reducing the magnitude from a mechanical point of view
Solution Approach 1:
The patent segments the sensing function into a distributed scale pattern across the movable body and a corresponding sensing yoke structure. Instead of using multiple discrete Hall sensors, the scale pattern is divided into multiple segments that work together with the sensing yoke to provide comprehensive position information, reducing mechanical magnitude while maintaining accuracy.
3Object-affected harmful factors
If a permanent magnet is used for Hall sensor detection, then the magnetic force detection is enabled, but the flux of the permanent magnet affects the surrounding electronic components
Solution Approach 1:
The patent extracts the permanent magnet from the sensing system, eliminating the source of magnetic flux interference. Position detection is achieved through the mechanical interaction between the sensing yoke and the scale pattern, without requiring any magnetic components. This extraction removes the harmful magnetic field effects while preserving the essential detection capability.
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 improves shake correction performance by allowing precise control of the driving force and simplifying the control configuration, while also reducing mechanical complexity and costs.
Implementation Method 1
a position sensing unit configured to sense a position of the first movable body, and comprising a sensing coil, disposed on any one of the first movable body and the fixed body, and a sensing yoke unit disposed on the other of the first movable body and the fixed body
Data Source
AI summary
A sensor shifting actuator is provided. The sensor shifting actuator include a first movable body in which an image sensor having an imaging surface is disposed, a fixed body in which the first movable body is disposed to be movable in first and second directions parallel to the imaging surface, a driving unit configured to provide a driving force to the first movable body, and a position sensing unit configured to sense a position of the first movable body and including a sensing coil disposed on any one of the first movable body and the fixed body and a sensing yoke unit disposed on the other thereof, wherein the sensing yoke unit includes a plurality of sensing yokes spaced apart from each other in a direction orthogonal to the imaging surface, and each sensing yoke is configured to change in width in a moving direction of the first movable body.