With the miniaturization and light-weight of photoelectric instruments, the original method to change the focal length of lens mechanically can't meet the requirements now. Then variable-focus lens without mechanical elements appears. In recent years, varieties of variable-focus lenses, which have variable surfaces radius or variable refractive index, are put forward. The variable-focus lenses with variable surface radius mainly include variable-focus double liquid lens based on EWOD, variable-focus lens based on hydraulic pressure, ultrasonic variable-focus optical lens and so on. The variable-focus lens with variable refractive index mainly includes liquid crystal lens. This article introduces these kinds of variable-focus lenses and expounds the problems to be solved. It also analyzes the developing trend of variable-focus lens. KEYWORDS: variable-focus lens, EWOD, variable-focus double liquid lens, hydraulic pressure liquid lens, ultrasonic variable-focus optical lens, liquid crystal lens
In order to cure the cataract disease or injuries in eyes, intraocular lens(IOL) has been studied all the time to replace the crystalline lens in human eyes. Researches on IOL are started early from 19th century, and it develops greatly in the hundreds years after. This article introduces several main kinds of IOLs that appear in the development history of IOL, and raises the double-liquid zoom IOL based on electrowetting, which will be the trend of IOL study.