Work

Ultrathin Variable Aperture Mechanism Utilizing a Micro Flat Motor With a Multipole Ring Magnet

Year: 2025

Type: article

Abstract: Recent advancements in smartphone camera technology have led to the integration of variable aperture mechanisms to enhance image quality. This study introduces a 0.8 mm thick variable aperture mechanism driven by a micro flat motor. The motor incorporates an 80 poles ring magnet, magnetized using a laser-assisted local heating method, with an outer diameter of 9.6 mm, inner diameter of 7 mm, and thickness of 0.3 mm, and magnetization width of 0.3 mm. The stator features a two-phase planar micro meander coil with a mechanical angle shift of 2.25°, enabling rotational angle control using Hall sensors and a phase-locked loop. The experimental tests demonstrated that the motor achieved a step response with a target angle of 9° and a settling time of 0.18 s. The aperture mechanism, comprising six polyacetal polymer blades, successfully demonstrated opening and closing operations with the opening diameter changed from 6.1 to 1.4 mm by the motor rotation.

Source: IEEE Access

DOI: 10.1109/access.2025.3527146

Authors: Keita Nagai, Riku Fukazawa, Yu Okawara, Haruhiro Komura, Tadahiko Shinshi

Institutions: Tokyo Institute of Technology, MinebeaMitsumi (Japan)

Language: English

Topic: Electric Motor Design and Analysis

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,075

Funders: Precise Measurement Technology Promotion Foundation, Japan Science and Technology Corporation, Amada Foundation, Japan Society for the Promotion of Science