| Summary: | 碩士 === 國立交通大學 === 光電工程學系 === 99 === Cell phone combined with camera function is the main trend in recent years. Most camera phones in present day utilize digital zoom function to zoom in. However, the image quality using digital zoom function is worse than using optical zoom function. Conventional optical zoom function is achieved by mechanical moving lens in a zoom lens system. Zoom lens require some volume to contain lots of lens components and have mechanical damage issue in long-term use. Applying the conventional zoom lens in the camera phone is a great challenge.
In this study, a tunable-focus liquid crystal lens exhibiting ultra-fast focusing and low operating voltage was proposed. The inside electrode configuration with a central controlling electrode is combined with a high resistance layer to conserve electric power efficiently. Moreover, the smooth gradient electric field distribution is maintained by the high resistance layer. Compared with conventional liquid crystal lens, this gradient driven liquid crystal lens (GD-LC lens) decreased the operating voltage from twenty more voltage to 5 voltages. And with using Over-Drive method, GD-LC lens decreased focusing response time from thirty seconds to 0.2 second. This GD-LC lens has unique characteristic such as electric tunable focus, no mechanical moving part, small volume, low operating voltage and short response time which is suitable for camera phones application.
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