High-definition and high-sensitivity CMOS image sensor with all-pixel image plane phase-difference detection autofocus

Abstract

In this paper, we describe an overview of autofocus (AF) technology for digital still cameras, video camcorders, and smartphones. Subsequently, we propose a CMOS image sensor (CIS) with all-pixel image plane phase-difference detection AF (PDAF) and describe a device structure and an optical design for fast and high-quality AF and low-noise imaging. To perform both PDAF and imaging function in all pixels, an individual pixel is composed of two horizontally displaced sub-photodiodes (PDs) and one microlens (ML). In particular, we describe PD and pixel isolation technology for high-definition, high-sensitivity, and low-noise PDAF-CIS with about front-side-illuminated (FSI) 6.4-µm-size pixel and back-side-illuminated (BSI) 1.X µm-size pixels.