Rotatable Reflection Module Camera Position Sensing Accuracy
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Solution Overview
Problem
The complexity and increased size of camera modules in portable electronic devices due to the implementation of autofocusing, zoom, and optical image stabilization functions lead to position distortion and reduced position sensing accuracy, particularly when the position of a magnet is shifted during assembly or due to external impacts.
Innovation Solution
A camera module design that includes a rotation holder with a reflective member and position detection sensors, where the magnet is biased opposite to the housing and the position detection sensors are strategically placed to enhance sensing accuracy, minimizing the influence of current applied to coils and external impacts, and optimizing the relative position with magnets to improve sensing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall sensor is provided in a coiled portion of a conventional coil to sense magnet position, then position sensing is enabled, but position distortion occurs when current is applied to the coil and sensing accuracy deteriorates when magnet position is slightly shifted
Solution Approach 1:
The patent extracts the Hall sensor from the coiled portion and relocates it to a position outside the coil structure. This separation eliminates the harmful interaction between the current-generated magnetic field in the coil and the Hall sensor, preventing position distortion when current is applied while maintaining accurate magnet position sensing capability
Solution Approach 2:
The patent introduces a magnetic shielding structure as an intermediary element between the coil and the Hall sensor. This shielding structure blocks the magnetic field generated by the coil current from reaching the Hall sensor, thereby preventing position distortion while allowing the sensor to accurately detect the magnet's position
2Adaptability or versatility
If the camera module includes folded modules for zoom and OIS functions, then these functions are improved, but the device thickness increases
Solution Approach 1:
The patent implements a nested structure where the reflection module is positioned within the housing in a space-efficient manner, and the rotation holder with reflective member is integrated into the existing camera module architecture. This nesting approach allows zoom and OIS functions to be achieved without proportionally increasing the overall device thickness
Solution Approach 2:
The patent utilizes the thickness direction (optical axis direction) for the rotation holder's rotational movement rather than extending the device in lateral dimensions. By making the reflection module rotatable about an axis perpendicular to the optical axis, the system achieves zoom and stabilization functions through angular movement in the thickness dimension, avoiding lateral expansion of the device
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 design minimizes the impact of current and external factors on position sensing accuracy, allowing for more precise positioning and increased sensitivity, thereby maintaining high sensing accuracy even when the magnet's position is slightly shifted, and enables the implementation of AF, zoom, and OIS functions without increasing the device's thickness.
Implementation Method 1
a magnet disposed on a side surface of the rotation holder, parallel to an optical axis direction, and a first position detection sensor disposed in the housing to face the magnet and configured to sense movement of the rotation holder in a second axis direction
Data Source
AI summary
A camera module includes a housing, a rotation holder including a reflection member, and supported on an inner wall of the housing such that the reflection member is rotatable about a first axis, perpendicular to an optical axis and parallel to a bottom of the housing, a magnet provided on a side surface of the rotation holder, parallel to an optical axis direction, and a first position detection sensor provided in the housing to face the magnet and configured to sense movement of the rotation holder in a second axis direction, perpendicular to the optical axis and the first axis, wherein the magnet is disposed to be biased in a direction, opposite to the inner wall of the housing on which the rotation holder is supported in the optical axis direction.