Abstract: In a differential signal transmission cable, a surface of a skin layer is partially provided with shield conductors disposed at respective equidistant portions spaced apart in a direction orthogonal to a direction in which two signal conductors are arranged, the equidistant portions each being distant by the same distance from axial centers of the signal conductors. On the surface of the skin layer, the shield conductors are not provided in areas located in the direction in which the signal conductors are arranged, and spaces are created in these areas.

Abstract: A communication module-cooling structure includes a main body section to be cooled by a cooling mechanism, and a heat sink including a cooling receiving section including partition walls and slit-shaped receiving spaces defined by the partition walls. The receiving spaces of the cooling receiving section receive communication modules, and each of the communication modules includes a substrate mounted with a communication circuit component thereon and first and second sidewalls which sandwich the substrate therebetween in a thickness direction of the substrate. At least one of the first and second sidewalls of each of the communication modules is in surface contact with an inner surface of each of the receiving spaces.

Abstract: A differential signal cable is composed of two inner conductors, an insulator, which covers the two inner conductors separately or together, and an outer conductor, which covers a circumference of the insulator. When measured in a cable length of 1 m, an effective capacitance difference ?X represented by Formula (1) below is not greater than 0.2 percent of an average value C of capacitances of the two inner conductors, ?X=?C+?L/Z02??(1), where ?C is a difference in capacitance between the two inner conductors, ?L is a difference in inductance between the two inner conductors, and Z0 is a reference impedance (50 ohms).

Abstract: Thermal connection between a plurality of communication modules and a heatsink placed on these communication modules is securely achieved and maintained. In a signal transmission device in which a common heatsink is arranged on a plurality of communication modules equipped on a board, the signal transmission device has a coil spring provided between the board and the communication modules, and the communication modules are biased toward the heatsink by the coil spring so that an upper surface of the communication module is pressed against a bottom surface of the heatsink.

Abstract: A height of a signal transmission device is decreased as low as possible as maintaining or improving a cooling performance for the communication module. Ina signal transmission device provided with a communication module provided on a substrate and a cooling mechanism for cooling the communication module, the cooling mechanism includes: a heat-transfer plate including a first region which overlaps with bottom surfaces of a plurality of the communication modules and is thermally connected to the bottom surfaces and a second region which does not overlap with the bottom surfaces of the communication modules; and a heat-release fin provided in the second region of the heat-transfer plate.

Abstract: A differential signal cable is composed of two inner conductors, an insulator, which covers the two inner conductors separately or together, and an outer conductor, which covers a circumference of the insulator. When measured in a cable length of 1 m, an effective capacitance difference ?X represented by Formula (1) below is not greater than 0.2 percent of an average value C of capacitances of the two inner conductors, ?X=?C+?L/Z02??(1), where ?C is a difference in capacitance between the two inner conductors, ?L is a difference in inductance between the two inner conductors, and Z0 is a reference impedance (50 ohms).

Abstract: In a differential signal transmission cable, a surface of a skin layer is partially provided with shield conductors disposed at respective equidistant portions spaced apart in a direction orthogonal to a direction in which two signal conductors are arranged, the equidistant portions each being distant by the same distance from axial centers of the signal conductors. On the surface of the skin layer, the shield conductors are not provided in areas located in the direction in which the signal conductors are arranged, and spaces are created in these areas.

Abstract: An optical communication module includes an optical element array, a supporting member on which the optical element array is placed, an optical member for optically coupling the optical element array and a plurality of optical fibers together, a plurality of grooves provided in the supporting member or the optical member, and a plurality of protrusions provided on the optical member or the supporting member in correspondence with the grooves respectively. The grooves and the protrusions are mated together. The grooves are provided as being widened toward their openings. The grooves and the protrusions are each provided so that a location in a width direction at which no relative locational misalignment occurs therebetween lies on a line through the center of the optical element array. The grooves and the protrusions are each provided on at least two or more different lines through the center of the optical element array.

Abstract: Thermal connection between a plurality of communication modules and a heatsink placed on these communication modules is securely achieved and maintained. In a signal transmission device in which a common heatsink is arranged on a plurality of communication modules equipped on a board, the signal transmission device has a coil spring provided between the board and the communication modules, and the communication modules are biased toward the heatsink by the coil spring so that an upper surface of the communication module is pressed against a bottom surface of the heatsink.

Abstract: A height of a signal transmission device is decreased as low as possible as maintaining or improving a cooling performance for the communication module. Ina signal transmission device provided with a communication module provided on a substrate and a cooling mechanism for cooling the communication module, the cooling mechanism includes: a heat-transfer plate including a first region which overlaps with bottom surfaces of a plurality of the communication modules and is thermally connected to the bottom surfaces and a second region which does not overlap with the bottom surfaces of the communication modules; and a heat-release fin provided in the second region of the heat-transfer plate.

Abstract: An optical communication module includes: an optical element array; a supporting member on which the optical element array is placed; an optical member for optically coupling the optical element array and a plurality of optical fibers together; a plurality of grooves provided in the supporting member or the optical member; and a plurality of protrusions provided on the optical member or the supporting member in correspondence with the grooves respectively. The grooves and the protrusions are mated together. The grooves are provided as being widened toward their openings. The grooves and the protrusions are each provided so that a location in a width direction at which no relative locational misalignment occurs therebetween lies on a line through the center of the optical element array. The grooves and the protrusions are each provided on at least two or more different lines through the center of the optical element array.

Abstract: A semiconductor device includes a plate shaped semiconductor package substrate, a semiconductor chip mounted on the semiconductor package substrate, a plurality of electrodes formed on a lower surface of the semiconductor package substrate, the plurality of electrodes being electrically connected to a mother board; and a connector formed at an end of the semiconductor package substrate. The connector includes a plurality of terminals to be electrically connected to a plurality of spring terminals of a mating connector which is mated in a parallel direction to the semiconductor package substrate.

Abstract: A communication module-cooling structure includes a main body section to be cooled by a cooling mechanism, and a heat sink including a cooling receiving section including partition walls and slit-shaped receiving spaces defined by the partition walls. The receiving spaces of the cooling receiving section receive communication modules, and each of the communication modules includes a substrate mounted with a communication circuit component thereon and first and second sidewalls which sandwich the substrate therebetween in a thickness direction of the substrate. At least one of the first and second sidewalls of each of the communication modules is in surface contact with an inner surface of each of the receiving spaces.