Optical Image Stabilization Hall Sensor Positioning for Accuracy
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Solution Overview
Problem
Conventional camera modules with optical image stabilization (OIS) face challenges in miniaturization due to increased size and complexity, particularly with position sensing accuracy issues caused by current-induced position distortion and assembly tolerance shifts in the hall sensor system.
Innovation Solution
A reflection module with a hall sensor system optimized to oppose the N pole or S pole of a magnet for enhanced sensing accuracy, reducing position distortion and improving sensitivity by positioning the hall sensor to maximize magnetic flux density, thereby maintaining accuracy even with slight magnet shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hall sensor is provided in the winding of a conventional coil for optical image stabilization, then the camera module can implement position sensing, but position distortion occurs due to current applied to the coil and assembly tolerance shifts
Solution Approach 1:
The hall sensor is extracted from the conventional coil winding and repositioned to face the magnet directly from outside the coil windings. This separation removes the harmful influence of coil current on the sensor while maintaining the magnetic field sensing capability, thereby eliminating position distortion caused by current application and assembly tolerance shifts.
2Adaptability or versatility
If the camera module includes additional components for optical image stabilization and zoom functions, then more functions are implemented, but the size and complexity of the camera module increase
Solution Approach 1:
The reflection member is designed to serve multiple functions: it enables zoom by changing the optical path length, implements optical image stabilization through angular adjustment, and facilitates autofocus. By making the reflection member multi-functional, the patent reduces the need for separate dedicated components, thereby decreasing overall module complexity while maintaining versatile functionality.
Solution Approach 2:
The patent integrates multiple functional components into a compact nested structure where the reflection member, magnet, coil, and hall sensor are arranged in a space-efficient configuration. The hall sensor is positioned outside the coil windings yet remains functionally integrated, allowing compact arrangement that reduces overall module size while maintaining all necessary functions.
3Measurement precision
If the hall sensor is positioned to face the magnet for enhanced sensing, then sensing accuracy improves, but the sensor becomes more sensitive to position shifts
Solution Approach 1:
The hall sensor is extracted from the conventional coil winding and repositioned to face the magnet directly from outside the coil windings. This separation removes the harmful influence of coil current on the sensor while maintaining the magnetic field sensing capability, thereby eliminating position distortion caused by current application and assembly tolerance shifts.
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 significantly reduces position sensing errors and enhances sensitivity, allowing for more precise optical image stabilization and miniaturization of camera modules in portable devices.
Implementation Method 1
a hall sensor disposed in the housing and opposing an N pole or an S pole of the magnet
Implementation Method 2
a coil disposed in the housing and opposing the magnet
Data Source
AI summary
A reflection module for optical image stabilization includes a rotation holder, which includes a reflection member and is supported on an internal wall of a housing, and a driving part to provide driving force to move the rotation holder. The driving part includes a magnet disposed on the rotation holder, a coil disposed in the housing and opposing the magnet, and a hall sensor disposed in the housing and opposing an N pole or an S pole of the magnet.