Abstract: A housing structure of an acoustic controller having a lower case which is lightweight, high in the degree of freedom in shape design, and capable of suppressing a deformation of side walls thereof after being molded. The lower case is integrally formed from resin into a rectangular dish shape having front, rear, left, right, and bottom plates. An upper unit is attached to an open upper part of the lower case. The left and right plates of the lower case have upper parts thereof formed into brim portions protruding outward in the left-to-right direction. Front and rear parts of each brim portion are further protruded outward and formed into flanges that function as mounting portions used for mounting the acoustic controller to a rack.

Abstract: A housing structure of an acoustic controller, in which a lower case of the controller has an increased rigidity and improved moldability. The lower case is integrally formed by a resin and has a bottom surface thereof disposed to face a tabletop surface when the controller is in a stationarily placed thereon. The bottom surface of the lower case is formed to have a concave-forming portion that defines a concave space communicating with the outside of the controller on the left and right sides thereof and which is upward convex as viewed when the controller is stationarily placed, thus increasing the rigidity of the lower case. Bosses and vertical ribs formed to project upward from a horizontal part of the concave-forming portion of the lower case each have a reduced height, thereby improving the moldability of the lower case.

Abstract: A projection type video display reduces the flicker in projection images caused by the brightness fluctuation of a light source lamp regardless of the kind of lamp used as a light source lamp. The projection type video display includes a driving control circuit for a light source lamp to control a discharge voltage of the light source lamp to prevent flicker caused by brightness fluctuation.

Abstract: A projection type video display reduces the flicker in projection images caused by the brightness fluctuation of a light source lamp regardless of the kind of lamp used as a light source lamp. The projection type video display includes a driving control circuit for a light source lamp to control a discharge voltage of the light source lamp to prevent flicker caused by brightness fluctuation.

Abstract: In a display device comprising a cooling suction fan and an air filter arranged on the suction side of the cooling suction fan, there are provided first means for measuring the value of a current flowing through a power supply line to the cooling suction fan for each predetermined time period, and second means for judging that the air filter is clogged when the measured current value is not more than a predetermined reference value, to inform the user that the air filter is clogged.