Title :
High dynamic-range CMOS image sensor cell based on self-adaptive photosensing operation
Author :
Lee, Sungsik ; Yang, Kyounghoon
Author_Institution :
Div. of Electr. Eng., Korea Adv. Inst. of Sci. & Technol., Daejeon
fDate :
7/1/2006 12:00:00 AM
Abstract :
This brief presents the performance characteristics of a new CMOS active pixel structure based on a self-adaptive light-sensing operation, which is implemented using a standard 0.35-mum CMOS logic process. In order to improve the dynamic range (DR) as well as the sensitivity at low illumination intensity, a new photogate structure is proposed and incorporated into the pixel structure. At an optimum bias condition of the photogate, the DR was increased by more than three times and the sensitivity at low illumination intensity was improved by two times compared to the conventional structure. The new pixel structure is found to allow simultaneous improvements in both the DR and the sensitivity without any process modification
Keywords :
CMOS image sensors; optical sensors; 0.35 micron; CMOS active pixel structure; CMOS image sensor cell; CMOS logic process; dynamic range; illumination intensity; optimum bias condition; photogate structure; self-adaptive light-sensing operation; self-adaptive photosensing operation; CMOS image sensors; CMOS logic circuits; CMOS process; Capacitance; Digital cameras; Dynamic range; Lighting; Mobile handsets; Photodiodes; Voltage; Adaptive sensitivity; CMOS active pixel sensor (CAPS); dynamic range (DR); photogate;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2006.875805
