The microbolometric exact theoretical output responsivity expression for a focal plane array is obtained for the first time. Based on the physical thermal model for a microbolometer, the temperature change behavior of the microbolometer is analyzed and discussed to get its theoretical temperature change expression under pulse voltage bias. With the temperature change expression and infrared response analysis of the microbolometer, the theoretical output responsivity expression is successfully derived. The theoretical responsivity expression reveals some key factors that affect and determine th...