A liquid crystal display apparatus has R, G, and B LEDs and a light guide plate for guiding and diffusing the light entering through an incident surface evenly over the plate. The controlling apparatus controls operation of a tool changer which comprises a changer arm for holding tools and is adapted to pivot the changer arm by a driving system including a servo motor and exchange the tool attached to a main spindle in a tool changing position and the tool in a predetermined position. The first set of metrics including a first loads matrix and a first scores matrix.