One or more treatment parameters are determined for a cornea reshaping procedure. According to the invention, the filter assembly comprises a filter element for attenuating the x-ray beam, and at least a support plate which fixes the filter element. or higher but lower than 170\xb0 C. The divided active matrix substrate is chamfered along its edges. The trap circuit attenuates frequency-modulation broadcast-band signals that are in proximity to the desired terrestrial television broadcast signals or are broadcast within a band that are received at one half of the frequency of the desired terrestrial television broadcast signals.