Ultracompact optical zoom lens for mobile phone

Abstract

Recently, high-end mobile camera phones are spreading rapidly all over the world. In addition, the demands for the optical zoom as new function of the mobile camera phones are very intense. However, it has been very difficult for the module manufacturers to propose an ultra compact zoom lens unit which can be mass-producible and fit into the size of mobile phones. The following three key technologies are essential to mount optical zoom lens units onto mobile phones maintaining the portability of them. Those are a) optical design method which can achieve ultra compact size and mass productivity by utilizing plural aspherical glass-mold lenses and controlling decentering sensitivities, b) precise lens alignment system to compensate the field tilt caused by errors in the fabrication processes such as glass lens molding and lens assembling, and c) long-stroke compact lens actuators based on our unique SIDMs (Smooth Impact Drive Mechanisms) technology. By integrating these technologies, we have developed 3 times optical zoom lens unit suitable for 3 to 5 mega-pixel cameras. The size of our lens unit is one of the world's smallest. The technologies have shown the new orientation in the future of high-end mobile camera phones. In this paper, we show the foregoing three technologies and our next generation zoom lens unit under development.