Abstract: An optical module including a substrate, an optical waveguide formed on the substrate, and an optical element mounted on the substrate so as to be optically coupled to an end of the optical waveguide, for performing conversion between light and electricity. The optical module further includes a transparent resin for covering at least an optical coupling portion between the optical waveguide and the optical element, and a thermoplastic resin for covering only the optical element and its periphery including the transparent resin to seal the optical element.

Abstract: The inside of a crankcase for a four-cycle engine is divided by a bulkhead into a crank chamber and a transmission chamber. A crankshaft and a balancer shaft for suppressing engine vibrations by rotating in accompaniment with rotations of the crankshaft are rotatably attached within the crankshaft, and the balancer shaft is driven by the crankshaft via a gear set housed within the crank chamber. Meshing parts of a gear set can be sufficiently lubricated by oil mist without a special lubricating structure being required. Furthermore, the engine can be decreased in size without forming a sealed space for lubricating the gear set.

Abstract: A cover for underground structures, its cover body, and its frame designed to quickly discharge accumulations of rainwater and dirt so as to prevent slipping and skidding from increasing due to these accumulations. The cover body has a multiplicity of patterns of projections and depressions on its surface, one projection independent of another, so that the upper surface of each projection is on about the same level as that of the frame with the depressions formed to surround each of these depressions. The depressions are constructed to become gradually deeper from the central part of the cover body toward the periphery, while the frame also has depressions set up on part or all of its upper surface in a circumferential direction with discharge guides sloping up toward the outer periphery of the frame. The cover for underground structures is made up of a set of the cover body and the frame.