(In Japanese) 小型画素イメージセンサに向けた デュアルコンバージョンゲイン方式の検討

2023 Sep

Authors 坂野 綾香*、立田 一葵*、大谷 愛*、大倉 俊介*
宮内 健, 森川 有輝, 韓 相萬, 大和田英樹, 高柳 功
(*Ritsumeikan University)

IST 2023

High Dynamic Range (HDR) CMOS image sensors are required for the use under extreme-illminated environments
such as outdoors. Besides, for the Trillion Sensors Univers, low-cost image sensors are also required for mass-production.
However, conventional Dual Conversion Gain (DCG) CMOS image sensor pixel consists of 6 transistors, which results in
large pixel size and the increase of the chip cost. Therefore, we investigated a HDR pixel by performing two readouts consists
of 4 transistors pixel, which is suitable for small-area pixels. The photoelectrons integrated in the pixel is first readout only
with floating diffusion node FD at high conversion gain (HCG) and is then readout with the FD and photodiode (PD) at low
conversion gain (LCG). Although the linearity was reduced from conventional readout scheme, a 2.2dB higher dynamic range
was achieved.
Key words CMOS image sensor, HDR, 4T pixel, small area, DCG