Multi-degree-of-freedom active alignment for camera modules via a sequential method and streamlined setup.

Area of Science:

• Optical Engineering
• Manufacturing Technology

Background:

• Cumulative misalignments in optical modules degrade imaging quality, necessitating precision alignment in advanced manufacturing.
• Traditional passive alignment is inefficient, and current active alignment (AA) methods often require specialized equipment, limiting accuracy, speed, and practicality.

Purpose of the Study:

• To introduce a sequential active alignment (AA) method using modulation transfer function (MTF) for efficient and accurate optical module alignment.
• To address the limitations of existing AA techniques by developing a practical, fast, and accurate multi-degree-of-freedom alignment process.

Main Methods:

• A sequential AA process was developed, starting with compensating lens group decenters using a sensitivity matrix derived from defocus curves.
• Lens group tilt was optimized using Bayesian optimization (BO), followed by image sensor fine-tuning leveraging physical information from multiple fields of view (FoVs).

Main Results:

• The proposed method achieved optical module alignment in 8.485 seconds, representing a 59% improvement over traditional search-based methods.
• The AA method demonstrated superior average modulation transfer function (MTF) values compared to mainstream solutions, indicating enhanced imaging quality.

Conclusions:

• The developed sequential AA method offers an accurate, efficient, and practical solution for multi-degree-of-freedom alignment of camera modules.
• This approach holds significant potential for industrial application in advanced manufacturing, improving imaging quality and production efficiency.