Focus-tunable imaging analyses of the liquid lens based on dielectric elastomer actuator

In order to simulate the auto-focusing function of human eyes, a liquid lens is proposed based on dielectric elastomer actuator (DEA). The lens could realize rapid focusing under voltages. The structure and principle of the lens are described in detail. A novel fabricating method is presented for the lens, which is inspired by the negative pressure technology. A negative pressure region is made in the centre of the dielectric elastomer (DE) membrane, and the liquid is filled. Then the other layer of membrane is covered to seal the liquid. Around the lens is the DEA coupling carbon grease electrodes. The finite element analysis and simulation of the lens deformation are carried out by using the software of Abaqus. The relationship is explored among lens diameter, volume, pretension ratio, actuating voltage and focal length. It is found that when the liquid volume is fixed in the soft lens, the larger the pre-stretching ratio is, the greater the lens deformation is. At the condition of the same lens diameter, focal-length changes are inversely proportional to the liquid volume. The correctness of built theoretical models is verified by experiments in the end.