Abstract
A couple of ultra-high-speed image sensors were developed and evaluated: (1) NanoSIS (Nano-second image Sensor) operating at 100 Mfps (t = 10 ns) with about 600 kpixels each with 5 in-pixel memory frames and (10 frames for 300 kpixels)， and (2) ISAS (Image Signal Accumulation Sensor) operating at 50 Mfps (t = 20 ns; the deign target) with 32x32 pixels each with 1，220 in-pixel memory frames. The design modification based on the evaluation is going on. Examples of the problems and the countermeasures are reported. For the NanoSIS， the charge handling capacity Qmax was lower than the design target; for the ISAS， the frame rate did not reach the target value. The causes and the countermeasures are explained.
