A left electronic-component compartment has a left FPC receiving port, through which a flexible printed circuit (FPC) is inserted into the left electronic-component compartment, located adjacent to a left hinge. In the left electronic-component compartment, a left waterproof member is fitted adjacent to a left connector, which serves as a connection between the FPC and a battery. The left waterproof member prevents moisture, dust, and other foreign matter from entering the battery. A right electronic-component compartment has a right FPC receiving port, through which the FPC is inserted into the right electronic-component compartment, located adjacent to a right hinge. In the right electronic-component compartment, a right waterproof member is fitted adjacent to a right connector, serving as a connection between the FPC and electric circuitry. The right waterproof member prevents moisture, dust, and other foreign matter from entering the electric circuitry.
