Next Generation Autofocus and Optical Image Stabilization System for Camera Modules Using Magnetic Shape Memory Actuators

Nikita Gabdullin,Jongsuk Ro,Hamza Ahmad

doi:10.1109/access.2020.3020647

Nikita Gabdullin, Jongsuk Ro + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.3020647

Copy DOI

Abstract

Currently, camera modules are used in a wide range of applications ranging from micropo-sitioning actuator systems used in smartphones to larger modules used in stationary cameras, CCTV, and others. Modern camera modules are required to perform positioning functions to improve the stability and quality of captured images. These functions mainly include the autofocus (AF) and optical image stabilization (OIS) functions. Traditionally, separate actuators and sensors are used for AF and OIS, each contributing towards energy consumption, module size, and manufacturing costs. This is particularly disadvantageous in the case of smartphones owing to their inherent space and battery charge limitations. This paper presents a novel Magnetic Shape Memory (MSM) actuator system that combines the AF and OIS functions, which are performed using two actuators; thus, this system is a simple, compact, and cost-effective solution to the drawbacks of conventional technology. Furthermore, the smart properties of MSM alloys reduce the energy consumption of these systems through the utilization of their inherent holding forces and the associated shape memory effect. The realization of AF and OIS functions is discussed and verified experimentally for the proposed actuator system using data obtained from a fabricated prototype.

Highlights

Cameras have become indispensable in modern technology, as stand-alone applications, components of various devices such as smartphones, or a part of large-scale systems such as vehicles or closed-circuit television (CCTV) [1]
STRUCTURE AND OPERATING PRINCIPLES OF THE PROPOSED Magnetic Shape Memory (MSM) ACTUATOR FOR CAMERA MODULE APPLICATIONS The proposed AF/optical image stabilization (OIS) MSM actuator system shown in Fig. 2 allocates the lens barrel in a holder between two MSM elements connected to mechanical springs
Whereas this paper focuses on the mechanism that combines AF and OIS functions and its experimental verification, future work will elaborate on the exact design of smartphone MSM actuator system following the guidelines in Section IV of this paper

Summary

INTRODUCTION

Cameras have become indispensable in modern technology, as stand-alone applications, components of various devices such as smartphones, or a part of large-scale systems such as vehicles or closed-circuit television (CCTV) [1]. Εmax determines the maximum deformation of the MSM element; a further increase in magnetic or mechanical stresses does not result in a shape change This has a direct impact on the size of MSM actuators and the entire actuator system. STRUCTURE AND OPERATING PRINCIPLES OF THE PROPOSED MSM ACTUATOR FOR CAMERA MODULE APPLICATIONS The proposed AF/OIS MSM actuator system shown in Fig. 2 allocates the lens barrel in a holder between two MSM elements connected to mechanical springs. This structure is typical for MSM actuators and consists only of an MSM element, a flux guide, and a coil. Where dl is the lens diameter, and ah is the width of the lens holder wall

ELECTROMAGNETIC ANALYSIS OF MSM ACTUATORS

FORCES ACTING ON MSM ELEMENTS IN CAMERA MODULES

CONCLUSION