A Time-of-Flight Range Image Sensor With Background Canceling Lock-in Pixels Based on Lateral Electric Field Charge Modulation

Sang-Man Han, Taishi Takasawa, Keita Yasutomi, Satoshi Aoyama, Keiichiro Kagawa, Shoji Kawahito
2015 IEEE Journal of the Electron Devices Society  
This paper presents a CMOS time-of-flight (ToF) range image sensor using high-speed lock-in pixels with background light canceling capability. The proposed lock-in pixel uses MOS gate-induced lateral electric field control of depleted potential of pinned photodiode for implementing a multiple-tap charge modulator while achieving a high-speed charge transfer for high-time resolution. A TOF image sensor with 320 x 240 effective pixels is implemented using a 0.11-µm CMOS image sensor process. The
more » ... OF sensor has a range resolution of less than 12 mm without background light and 20 mm under background line for the range from 0.8 to 1.8 m and integration time of 50 ms. The effectiveness of in-pixel background light canceling with a three-tap output pixel is demonstrated. INDEX TERMS CMOS image sensor, depth image, pinned photodiode, time-of-flight (ToF), lateral electric field charge modulator (LEFM) 2168-6734
doi:10.1109/jeds.2014.2382689 fatcat:bccsxg7wojhbdmv4cc57a5b634