Imaging Lens Barrel Position Detection with Multi-Wavelength Magnetic Scales
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Solution Overview
Problem
Existing imaging lens barrels lack the accuracy in detecting the position of imaging lenses, which is crucial for improving image quality on larger and higher resolution display screens.
Innovation Solution
An imaging lens barrel with a rotating body featuring parallel magnetic scales of different wavelengths, coupled with magnetic sensors and phase difference calculation and correction mechanisms, allows for precise detection of the imaging lens position by calculating and correcting phase differences to determine the absolute position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a simple lens position detection method is used, then the device complexity is reduced, but the measurement precision of lens position is insufficient
Solution Approach 1:
The detection system is segmented into multiple magnetic scales with different wavelengths (first magnetic scale with wavelength λ1, second magnetic scale with wavelength λ2) and multiple magnetic sensors. This segmentation allows the system to achieve high measurement precision through multi-wavelength interferometry while managing complexity by dividing the detection function across multiple simpler components working in parallel
Solution Approach 2:
The invention introduces a temporal dimension by measuring phase differences at multiple time points (first time point and second time point) during lens movement. This dimensional approach enables the system to calculate lens position with high accuracy by comparing phase changes over time, transforming a spatial measurement problem into a temporal measurement solution
2Measurement precision
If lens position is detected without considering moving speed, then the device complexity is reduced, but the measurement precision deteriorates due to speed-induced phase differences
Solution Approach 1:
The system implements feedback by detecting the actual moving speed of the lens during operation and using this information to compensate for speed-induced phase differences. The correction table stores pre-calculated compensation values that are applied based on the detected moving speed, creating a closed-loop system that continuously refines position measurement accuracy
Solution Approach 2:
The invention performs preliminary action by pre-calculating and storing correction tables for different moving speeds before actual lens positioning operations. These correction tables contain pre-determined phase difference compensation values that are quickly retrieved and applied during operation, avoiding the need for complex real-time calculations while maintaining high measurement precision
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 enables high-accuracy detection of the imaging lens position, improving image quality by accounting for variations in moving speed and direction, thereby enhancing the precision of image positioning.
Implementation Method 1
a first magnetic sensor configured to detect, from the first magnetic scale, a first phase signal and a second phase signal having a phase shift with respect to the first phase signal in response to a rotation of the rotating body; a second magnetic sensor configured to detect, from the second magnetic scale, a third phase signal and a fourth phase signal having a phase shift with respect to the third phase signal
Data Source
AI summary
An imaging lens barrel includes: a barrel body; a rotating body; a first magnetic sensor; a second magnetic sensor; a phase difference calculation section; a correction table memory that stores a plurality of correction tables which are obtained when the imaging lens is moved at different speeds and are used to correct a difference between the phase difference calculated by the phase difference calculation section and a design value of the phase difference; a phase difference correction section configured to correct the phase difference calculated by the phase difference calculation section, using a correction table corresponding to a moving speed of the imaging lens among the plurality of correction tables; and an absolute position calculation section.