A method for IQ mismatch calibration of a transmitter. The apparatus includes a housing with an open bottom. The ribs can have an at least partially curvilinear shape between the intermediate portion of the sidewall and the adjacent corner thereof, such as having an intermediate generally bell-shaped region such that a vertex of the concave region is higher on the sidewall than where its legs intersect the corners of the tray. A photo-curing polymer obtained in the present invention is suited for forming a protection film of a color filter and a column-like spacer of a liquid crystal panel. A method for stabilizing a material by incorporating such triazines is also disclosed.