Task of Imaging and Role of Image Sensors
Various kinds of instruments such as digital still cameras, camera phones, and camcorders allow to enjoy personal images. Image sensors have an image area on which optical images are focused and are converted to image signals for output. Image sensors have a scanning function, transmitting the light intensity information of each pixel to the output part, which reads out the intensity information as an electric signal. In capturing moving images, still images are taken at a constant time interval. Image sensors must possess three functional elements: a sensor part that generates and stores the signal charges; a scanning part that identifies or addresses the coordinate point of the pixel of the signal; and a signal charge quantity measuring part that measures the signal charge quantity and converts it to electric signals such as voltage, current, frequency, and pulse width.