Ultrasound liquid-gel hybrid lens using acoustic radiation forces

Conventional camera modules use a mechanical system comprising moving parts to change the focal length of the lens by moving it along the optical axis, increasing the volume of the camera. Here, the potential of compact variable-focus lenses was examined to enhance response speed and robustness via a combination of viscoelastic gel films, liquids, and acoustic radiation forces. The optical properties of the lenses were evaluated using a wavefront sensor. Focal lengths could be controlled by changing the lens shape via acoustic radiation forces generated by ultrasound vibrations. The response time of the lens was dependent on the thickness of the gel film on the lens surface; a thinner film thickness resulted in a shorter response time. The response times for hybrid lenses with gel film thickness of , 0.8 mm, 1 mm, and 2 mm were 58 ms, 68 ms, 82 ms, and 172 ms, respectively.