Camera Module Lens Control with Segmented Hall Sensors
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Solution Overview
Problem
Conventional camera modules face difficulties in linear control of lens groups due to limited sensing distances, leading to deteriorated control accuracy and non-linear sensor outputs, making precise lens movement challenging, especially with longer stroke lengths.
Innovation Solution
A camera module design featuring multiple Hall sensors spaced apart along the optical axis direction for a single movable lens, allowing for improved linearity of sensor outputs and enhanced control accuracy by compensating non-linear sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a moving distance of lens groups is lengthened to enable zooming function, then the zooming capability is improved, but the control accuracy deteriorates due to difficulty in linear control
Solution Approach 1:
The patent divides the sensing function into multiple segments by using several Hall sensors positioned at different locations along the optical axis. Each sensor monitors a specific segment of the lens group's movement range, allowing precise control across the entire long stroke distance by combining measurements from multiple segmented sensing zones.
2Device complexity
If only one sensor is used to control lens group movement, then the device complexity is reduced, but the control accuracy deteriorates due to non-linear sensor output over long stroke
Solution Approach 1:
The patent transitions from a single-point sensing approach to a distributed sensing array along the optical axis dimension. By positioning multiple Hall sensors at different axial locations, the system captures position information across the entire movement range, converting a one-dimensional control problem into a multi-point measurement system that maintains linearity throughout the stroke.
3Measurement precision
If multiple Hall sensors are positioned at different locations along the optical axis, then the linearity of sensor output is improved, but the device complexity increases
Solution Approach 1:
The patent makes the Hall sensor system multi-functional by using the same type of Hall sensor for multiple measurement points along the optical axis. Each sensor serves the dual purpose of detecting magnetic field strength and indicating positional information, allowing the system to maintain measurement precision across the entire zoom range while using standardized sensor components.
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 improves the linearity of sensor outputs, eases control of the lens driving unit, and increases accuracy and resolution, facilitating easier software calibration and more precise zooming functions.
Implementation Method 1
a plurality of sensors each mutually spaced apart to an optical axis direction relative to a single moving lens
Data Source
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AI summary
A camera module comprises: a movable lens including a first movable lens movably arranged in an optical axis direction, and a second movable lens arranged under the first movable lens; a fixed lens arranged under the movable lens; a driving unit including a body unit arranged on one side of the movable lens so as to move the movable lens in the optical axis direction; and a sensing unit for detecting the position of the movable lens, wherein the sensing unit respectively comprises: an upper sensing unit arranged on an upper end portion in the optical axis direction of the body unit; and a lower sensing unit arranged on a lower end portion in the optical axis direction of the body unit.