The invention provides an electro-optical device capable of reducing power consumption. The engine structure may define a combustion chamber and a crankcase in communication with a fresh air supply. Heat dissipation path includes: heat transfer path section provided in the through hole; and heat dissipation pattern section provided on the back face of substrate body, and connected to heat transfer path section. The height of the heat source and the warming rack can be adjusted to allow control over the cooking heat. Application to motion picture cameras. According to some embodiments to the present invention, prior to resynchronization of a data unit on the mirroring system with corresponding data on a primary unit, a consistent snap-shot of the data unit to be resynchronized is taken.