The present invention provides a liquid crystal display device of high quality having high brightness and uniform brightness distribution by focusing the light radiation direction from a light guide plate in the vertical direction with respect to a light radiation surface of the light guide plate. The bumper system further includes a pair of mounting brackets each attached to the rear wall and extending around the associated ends and forwardly to a location where it attaches to the front wall of the one end. The manner in which the object of the invention is achieved thus enables a delayed shutoff of the control device upon actuation of the key switch, and reliable operation of the control device. The formula is written to indicate that the A1 cation replaces Sr; the A2 cation replaces Si, and the A3 anion replaces O.