chapter  5
79 Pages

Types of Image Sensors

Optical images are focused on an image area in which pixels are arrayed in a matrix in a plane. An organic image sensor is one way of overcoming the above limits of silicon image sensors. Image sensors must have the following functions: a sensor part that converts incident light to signal charges and stores them; a scanning part that identifies the pixel address of each signal charge packet; and a part that measures the amount of signal charge and converts it to an electric signal. There are two challenges for three-transistor (3-Tr) pixel configuration. The first is to make extensive changes to improve sensitivity and dynamic range using organic materials as the photoconversion part. The other challenge is to overcome the disadvantage of 3-Tr pixel configuration by combining it with organic photoconductive material and creating a new pixel configuration with a noise reduction circuit by using feedback reset.