The present invention relates to methods to image the skin surface in order to view intercellular and intracellular structure. A full decision generator generates a full decision output. In addition, single channel interpolation is performed for spatial resolution conversion of any frame that does not refer to another frame. A channel protective layer is provided between the oxide semiconductor and a gate electrode provided over the oxide semiconductor. The size of aperture is such that the pressure in chamber combined with the supersonic jet and shock waves naturally forming therein do not result in catastrophic electron beam loss in chamber. Specifically, a rotatable locking mechanism that prevents the piston from moving fully upwards into the second latched position when a partial flush is desired, yet rotates to an unlocked position to permit the piston to move fully upwards into the second latched position when full flushing is desired.