A Smartphone-Based Fourier Ptychographic Microscope Using the Display Screen for Illumination

We propose a smartphone-mountable computational microscope that achieves wide-field and high-resolution imaging, based on the Fourier ptychographic (FP) microscopy technique. Our device uses the smartphone's built-in camera for microscopy imaging, the display screen for programmable illumination, and the computational power of the smartphone processors for FP image reconstruction. With a compact and lightweight optics module and a custom-built application, we can transform a regular smartphone into a high-performance microscope device with a space-bandwidth product exceeding that of regular benchtop microscopes. Our device achieves a half-pitch resolution of 870 nm over a wide field-of-view of 2.1 × 1.6 mm2 with amplitude, phase, and color imaging capabilities. We report on the design of the illumination and imaging system, our methods for fast FP reconstruction on the smartphone microscope, and the performance of the device. Using various clinical samples, we also discuss the potential of our device for clinical applications in resource-limited settings.