We successfully improved dynamic range characteristics in ultra high-speed CCDs. An equivalent circuit model of an ultra high-speed CCD was analyzed by Using a SPICE simulator to estimate the blunting of the input square wave pulse at the final step of the equivalent circuit. The result of the simulation clarified that the blunting of the input square wave pulse was the main bottleneck causing the drop in saturation signal level dependent on frame rate. A novel ultra high-speed CCD was designed and fabricated and can reduce the blunting of the input square wave pulse. The result of a driving experiment showed a dynamic range of 48.6 dB at one million frames per second, which is equivalent to digital 8 bits and 2.5 times higher than that of the previous ultra high-speed CCD.
2012 The Institute of Image Information and Television Engineers