Multi-Plane Phase Detection Autofocus for 8K Three-Chip Color Imaging Cameras.

A phase detection (PD) autofocus (AF) method for three-chip color imaging cameras is proposed. The method detects the focus state of a lens by calculating the disparity between a half-shielded PD pixel and other normal pixels corresponding to the same incident position among three sensors, which can perform accurate AF without employing state-of-the-art dual-photodiode technology. By using a prototype 8K sensor with half-shielded PD pixels (PD sensor), we demonstrated that installing the PD sensor into a blue channel of the three-chip system can achieve an excellent phase separation ratio and robust disparity calculation with less image quality degradation due to defects of PD pixels.