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

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.

Keywords

• Autofocus
• magnetic shape memory actuators
• optical image stabilization
• smart materials
• smartphone camera module