Development of a linear vibration motor with fast response time for mobile phones

Abstract

This research investigated the magnetic and mechanical characteristics of a linear actuator by using structural and magnetic finite element analyses as well as experimental verification. The response time to reach the steady state of vibration was investigated through the equivalent mass-spring-damper system of the linear actuator. The response time can be reduced by increasing the magnetic force or by decreasing the mass. In the case of decreasing the mass, the spring constant should also be decreased in order to maintain the same natural frequency. However, reduction of both the mass and stiffness decreases the vibration magnitude because it is proportional to the spring constant. The results show that the ideal method to reduce response time without decreasing vibration magnitude is to increase magnetic force. Finally, this research proposes a novel design of a linear actuator with a large magnetic force to reduce the response time.