Abstract

This study demonstrates a CMOS image sensor (CIS) with a hybrid optical structure which combines the benefits of Quad-cell and sparse AF optical structure. The hybrid structure has 1x1 micro-lenses to the green channel for low intra-channel signal differences (Ch diff) and better resolution and 2x2 micro-lenses to the red and blue channels for phase-detection auto-focus (PDAF). Serifs of micro-lens patterns are modified to reduce deformation caused by loading effects during micro-lens etching process. The hybrid structure shows improved sensitivity, signal-to-noise ratio (SNR), and intra-channel differences compared to Q-cell, with the green channel showing less than one-fifth of Ch diff than Q-cell. Measurements of the modulation transfer function (MTF) and real-image comparisons demonstrate that the hybrid structure provides better resolution and more detailed expression than Q-cell.