Variable focus smartphone based microscope using an elastomer liquid lens

We present a smartphone based microscope using elastomer liquid lens as the objective to achieve adjustable magnification without lens displacement or replacement. The microscope is small enough to fit into a pocket wallet and can work with smartphone cameras. Instead of using an elastomer membrane with a constant thickness, a membrane with a varied thickness profile is used to reduce the working pressure for improved reliability. Compared to the existing smartphone based microscopes, this microscope allows adjustable magnification without the needs for compromising the miniaturization. It thus promises potential applications in point-of-care diagnostics and other on-chip optical inspections.