A 1/2inch 48M All PDAF CMOS Image Sensor Using 0.8um Quad Bayer Coding 2x2OCL with 1.0lux Minimum AF Illuminance Level
Currently, there are two coding trends in mobile image sensors: Quad Bayer coding (QBC) and dual photodiode (DPD) QBC realizes high resolution and high dynamic range (HDR) whereas DPD achieves high phase detection auto focus (PDAF) performance. We propose a QBC with 2x2 on chip lens (2x2OCL) architecture as a potential next generation high performance CMOS image sensor. This combines high resolution, HDR, and high PDAF performance in one sensor. The critical issues of 2x2OCL are degradation of the resolution due to the sensitivity difference between 4 pixels under the same color filter and increasing the crosstalk among different colors. To overcome these issues, the OCL and pixel isolation shapes were optimized respectively. The world`s first image sensor using 2x2OCL architecture we prepared in this paper, has 1/2 inch 48M pixels with 0.8um QBC for high resolution, and all pixel PDAF achieved a minimum AF illuminance level of 1 lux.
2019 IEEE International Electron Devices Meeting (IEDM)