A spin chuck for holding a wafer to the front face of which a resist solution is supplied, a cup for housing the spin chuck and forcibly exhausting an atmosphere around the wafer by exhaust from the bottom thereof, and an air flow control plate, provided in the cup to surround the outer periphery of the wafer, for controlling an air flow in the vicinity of the wafer are provided. The first and second spectroscopic absorptions of the laser light are measured over specific first and second absorption lines. The imaging arrangement is electrically switchable between at two 3D modes, wherein the effective position of the imaging arrangement is shifted laterally between the modes with respect to the display pixel elements by an amount which is a non-integer multiple of the pitch between the pixel elements.