An analysis of fixed pattern noise for MOS-CCD type image sensors under quasi-stationary conditions

A theoretical explanation for fixed pattern noise (FPN) is given for the MOS-CCD image sensor with the use of external bias charge. The FPN is ascribed to the fluctuation of the bias charge which is returned from the coupler between the vertical transport line and the horizontal CCD (H-CCD) shift register. It is shown that the FPN is eliminated below -60 dB with respect to the maximum output signal in the case of vertical transfer efficiency of 97% or more.