Disclosed is a liquid crystal shutter that uses as a shutter a liquid crystal panel constructed by sandwiching DHF liquid crystal between a pair of substrates provided with one or more pixel electrodes and one or more counter electrodes, wherein a driving waveform for the panel has a write period comprising two subfields. An order of carrying out the steps of first connecting and second connecting is determined based on an address of a selected cell. Exhaust gas temperature is determined by using a Kalman filter.