Development of a cylindrical type ultrasonic motor

In recent years, the high-performance of a device in a mobile phone is realized by miniaturization and diversification of modules. For example, a new camera, which is improvement of a pixel, automatic focusing, and optical zoom module, is equipped. In addition, new functional devices, such as an HDD and Bluetooth, are planned as addition modules. Therefore, miniaturization of a module and decreasing electricity consumption are earnestly desired. For this purpose, development of miniaturized and little electricity camera module is required. 2) We have examined practical use of the cylindrical type ultrasonic motor. Compared with an existing lens actuator, the feature of it is space saving and power saving. This motor was proposed by Kumada as a center of gravity turn type ultrasonic motor. However, it has not been realized to practical use, because it is difficult to hold the cylinder element. In this paper, we describe relationships between holding method and fundamental characteristics of the motor.