An insulated structure including a backing surface, a bar coupled to and extending generally parallel to the backing surface, and a plurality of insulating blankets coupled to the bar. In one embodiment, the floorboard panel comprises a top skin, a frame, and a bottom skin. The busy signal enables a busy state when a power supply voltage value reaches a specified and guaranteed range after a power-on sequence. Interference between the beam portions are used to measure acceleration or pressure. The cost for the driver or the like can be reduced without giving an adverse influence such as luminance deterioration to characteristics.