Design of a digitally switchable multifocal microlens array for integral imaging systems

This paper presents the optical design of a digitally switchable multi-focal microlens array which can be used to extend the depth of field in integral imaging systems. The proposed switchable multi-focal microlens array consists of a customized freeform multi-focal microlens array (MLA) and a programmable spatial light modulator. By switching among the different optical powers of the switchable multi-focal MLA, an integral imaging system can render or capture a 3D scene at a large depth range around several central depth planes. We demonstrate the design considerations for a dual-focal microlens array with a primary and secondary focal lengths of 4mm and 4.06mm, respectively. We further validated the design by providing both interferometric measurements of the surface profiles and image contrast and resolution tests of a manufactured MLA prototype.