Camera Lens Centering Control for Wider OIS Correction Angle
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Solution Overview
Problem
Existing optical image stabilization (OIS) technologies face limitations in correction angle due to physical constraints and can cause overshooting or oscillation during lens movement, especially in low-light long exposure scenarios.
Innovation Solution
An active optical image stabilization (AOC) method using a variable attenuator and adaptive control to expand the correction angle by controlling the camera lens towards the central axis during unused exposure times, based on gyro data and image sensor information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the OIS lens is moved to the central axis during non-exposure section to expand correction angle, then the physical correction angle is expanded, but the time to move to center is reduced or completely absent in long exposure low-light environment
Solution Approach 1:
The system performs preliminary lens centering actions during non-exposure sections before long exposure shots. By proactively moving the lens to the central axis position in advance (during non-exposure moments), the system prepares the optical path for upcoming long exposure shots, ensuring maximum correction angle availability when exposure occurs.
Solution Approach 2:
The system dynamically adjusts lens movement strategies based on exposure conditions. During non-exposure sections, the lens is actively moved to center position, while during exposure sections, the lens maintains its position to avoid disrupting the optical path. This dynamic switching optimizes both correction angle expansion and image quality.
2Area of moving object
If the lens is moved to the center quickly in large angle during non-exposure section, then the correction angle is expanded, but overshooting or oscillation occurs at target position
Solution Approach 1:
The system implements periodic, step-by-step lens centering movements rather than a single large-angle move. The lens is moved in multiple smaller increments toward the central axis position, allowing each movement step to settle before the next begins. This periodic action pattern prevents overshooting and oscillation while still achieving the goal of expanding correction angle.
Solution Approach 2:
The system applies damping or deceleration control as the lens approaches the target center position. By reducing movement speed and applying cushioning forces before reaching the final position, the system prevents overshooting and oscillation, ensuring stable lens positioning for optimal correction angle utilization.
3Area of moving object
If the lens position reaches a physical limit during OIS correction, then correction in that direction is no longer possible, but moving the lens beyond the physical limit causes damage
Solution Approach 1:
The system performs preliminary lens centering during non-exposure sections to reset the lens to a neutral starting position. This preliminary action ensures that when exposure begins, the lens has maximum available travel range in both directions, effectively expanding the usable correction angle without requiring the lens to exceed its physical limits.
Solution Approach 2:
The system utilizes the time dimension by performing lens centering operations during non-exposure periods. This temporal separation allows the lens to be repositioned to optimal starting positions between shots, effectively expanding the correction angle availability without compromising lens safety or requiring physical limit exceedance.
Data Source
AI summary
An operation method of a camera module (180) according to the disclosure includes an operation (S101) of determining whether an unused time exists in which an image sensor (20) is not exposed, based on information about an exposure section of the image sensor (20) connected to a lens (60) for capturing an object, an operation (S102) of determining a motion value with respect to the camera module (180) based on gyro data generated by a gyro sensor (10) in case that the unused time existence, an operation (S103) of determining a target movement control angle with respect to the lens (60) based on the motion value, an operation (S104) of determining a movement angle per unit time with respect to the lens (60) based on the target movement control angle, and an operation (S105) of performing an active optical image stabilization OIS centering AOC control operation with respect to the lens (60) based on the determined movement angle per unit time.