Actuator Driver Lens Displacement Linearity Correction
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Solution Overview
Problem
Existing camera modules with optical image stabilizers face challenges in ensuring linearity between position detection signals and actual lens displacement, particularly in the XY plane, due to the difficulty in measuring displacement using laser displacement gauges or laser Doppler instruments, which are expensive and time-consuming.
Innovation Solution
An imaging device configuration that includes an actuator driver with a correction circuit to convert position detection signals into a second detection code with a linear relationship to actual lens displacement, using image movement data from the imaging element to calibrate and correct linearity without requiring expensive measurement instruments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser displacement gauge or laser Doppler measuring instrument is used to measure lens displacement, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses image data from the imaging element as a copy representation of lens displacement. Instead of directly measuring the lens physically, the system measures the displacement of the imaged object and infers the lens displacement from that image movement, thereby avoiding the need for complex measurement instruments.
Solution Approach 2:
The patent introduces image data as an intermediary to indirectly measure lens displacement. By measuring how much the imaged object moves on the imaging element, the system obtains information about lens displacement without requiring direct physical measurement devices.
2Measurement precision
If a laser displacement gauge is used to measure XY direction displacement, then measurement precision is improved, but loss of time and cost increase
Solution Approach 1:
The system uses image data as a copy of the optical field to obtain displacement information. By analyzing the movement of features in the captured image, the system determines lens displacement without requiring time-consuming physical measurement procedures.
Solution Approach 2:
The imaging element continuously captures images during the lens displacement process, providing continuous measurement data. This eliminates the need for separate measurement steps and allows displacement to be measured in real-time as part of normal imaging operation.
3Manufacturing precision
If correction functions are applied to compensate for nonlinearity, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The system uses image data to obtain actual lens displacement information and feeds this back to correct the position detection signal. By continuously comparing the detected position with the actual position derived from image analysis, the system compensates for nonlinearity through feedback correction.
Solution Approach 2:
The imaging device uses its own imaging function to measure and correct its own nonlinearity. The system leverages the image data already captured during normal operation to perform self-diagnosis and self-correction of displacement measurement accuracy, eliminating the need for external calibration equipment.
Data Source
AI summary
An imaging device includes: an imaging element; a lens disposed on a path of incident light to the imaging element; an actuator configured to displace the lens in a plane perpendicular to an optical axis; a position detecting element configured to generate a position detection signal indicating a displacement of the lens; and an actuator driver configured to feedback-control the actuator based on the position detection signal and a target code indicating a target displacement of the lens. The actuator driver includes: a correction circuit that converts a first detection code corresponding to the position detection signal into a second detection code having a linear relationship with an actual displacement of the lens; and a control circuit that controls the actuator so that the second detection code approaches the target code.