Lens Actuator Driver With Hall-Based Temperature Linearity Correction
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Solution Overview
Problem
Existing image capture apparatuses face challenges in maintaining high-precision and high-speed autofocus and image stabilization due to temperature-induced deviations in the linearity between position detection signals and actual lens positions, particularly in systems with phase difference detection and multiple camera modules, leading to adverse effects on image generation.
Innovation Solution
A lens control apparatus that utilizes a Hall element for simultaneous temperature and position detection, enabling temperature compensation and linearity compensation without additional sensors, and employs a control unit to correct temperature-dependent characteristics and linearity, allowing for high-precision and high-speed lens positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall element is used for position detection, then position detection precision is improved, but temperature-induced deviations in linearity occur
Solution Approach 1:
The Hall element is designed to perform dual functions: position detection and temperature detection. By utilizing the same component for both purposes, the patent eliminates the need for separate temperature sensors and enables real-time temperature compensation of the position detection signal, thereby maintaining linearity across temperature variations while preserving high position detection precision
Solution Approach 2:
The system implements feedback control by continuously monitoring the temperature through the Hall element and dynamically correcting the position detection signal based on temperature-induced deviations. This feedback mechanism ensures that the linearity between position detection signal and actual lens position is maintained despite temperature changes
2Measurement precision
If additional temperature sensors are added for temperature compensation, then temperature compensation precision is improved, but device complexity increases
Solution Approach 1:
The Hall element is designed to perform dual functions: position detection and temperature detection. By utilizing the same component for both purposes, the patent eliminates the need for separate temperature sensors and enables real-time temperature compensation of the position detection signal, thereby maintaining linearity across temperature variations while preserving high position detection precision
Solution Approach 2:
The Hall element serves itself by using its own temperature characteristics to detect temperature changes. This self-service approach allows the system to perform temperature compensation without requiring external temperature sensors or additional measurement circuits, thereby reducing device complexity while maintaining compensation precision
3Speed
If the lens position is directly changed to the position indicated by the position detection signal, then autofocus speed is improved, but positioning precision deteriorates due to temperature deviation
Solution Approach 1:
The system implements feedback control by continuously monitoring the temperature through the Hall element and dynamically correcting the position detection signal based on temperature-induced deviations. This feedback mechanism ensures that the linearity between position detection signal and actual lens position is maintained despite temperature changes
Solution Approach 2:
The patent applies parameter changes by introducing temperature compensation coefficients that modify the position detection signal based on the detected temperature. This allows the system to maintain high-speed positioning while correcting for temperature-induced deviations, thereby preserving positioning precision
4Device complexity
If temperature compensation is not performed, then device complexity is reduced, but image quality deteriorates due to positioning deviation
Solution Approach 1:
The Hall element is designed to perform dual functions: position detection and temperature detection. By utilizing the same component for both purposes, the patent eliminates the need for separate temperature sensors and enables real-time temperature compensation of the position detection signal, thereby maintaining linearity across temperature variations while preserving high position detection precision
Solution Approach 2:
The system implements feedback control by continuously monitoring the temperature through the Hall element and dynamically correcting the position detection signal based on temperature-induced deviations. This feedback mechanism ensures that the linearity between position detection signal and actual lens position is maintained despite temperature changes
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 provides accurate temperature compensation and linearity correction, ensuring high-precision and high-speed lens positioning, even in varying temperature conditions, thereby improving image quality and interlinking between multiple camera modules.
Implementation Method 1
a Hall element structured to generate a position detection signal indicating the position of the lens based on a Hall signal generated by the Hall element
Implementation Method 2
a temperature detection unit structured to detect a temperature based on a voltage across the Hall element in a state in which a constant current is applied to the Hall element
Data Source
AI summary
A position detection unit generates a position detection value PFB that indicates the position of a control target. A temperature detection unit generates a temperature detection value that indicates the temperature. A correction unit corrects the position detection value PFB. A controller generates a control instruction value SREF such that the position detection value PFB_CMP subjected to the correction matches a position instruction value PREF that indicates the target position of the control target. A driver unit applies a driving signal that corresponds to the control instruction value SREF to an actuator. The correction unit corrects the position detection value PFB such that the relation between the position detection value PFB and the actual position exhibits linearity that is uniform independent of the temperature.