A method of microwave pre treatment of a multi-phase material prior to a subsequent operation on the material. The first seat valve is designed as a valve aperture with a valve opening and a valve control edge and with a ball-shaped closing element that co-operates with the valve control edge. A non-refrigeration cycle based heating element is activated to provide heated air to an interior surface of a windshield if the climate control air temperature is above the control criterion value. In this manner, the scatter dots adjust the optical properties of the nearly dense features to be very similar to the optical properties of dense features, which enables more accurate imaging of the nearly dense features on the substrate.