Abstract: A printed board includes an insulating body that has a flat surface and includes insulating cloth including first fibers and second fibers that cross the first fibers at right angles on the flat surface, and printed wiring including a plurality of signal lines that run parallel to each other and are laid out on the flat surface of the insulating body so that a direction of the signal lines is tilted to a direction of the first or second fibers at an angle which is determined based on board-cutting efficiency of the insulating body and a predetermined delay-time difference between the signal lines.

Abstract: A technique is provided for improvement in convenience and in cost reduction of a fixing part of a printed board unit. A printed board unit includes a plurality printed board including a first printed board and a second printed board; and at least one fixing part, interposed between the first printed board and the second printed board, fixing the first printed board and the second printed board such that the first printed board and the second printed board overlap and keep a predetermined space between the first printed board and the second printed board, and the fixing part variably determines the predetermined space.

Abstract: A method for manufacturing an optical waveguide in which multiple cores are embedded in a parallel-arranged fashion within a single cladding, the cores having a refractive index of light different from that of the cladding, the method includes forming the multiple cores in a state where the adjacent cores are connected by a rib, forming the cladding around the rib and the multiple cores by curing a cladding material there around, and a cutting to the rib.

Abstract: A printed board includes an insulating body that has a flat surface and includes insulating cloth including first fibers and second fibers that cross the first fibers at right angles on the flat surface, and printed wiring including a plurality of signal lines that run parallel to each other and are laid out on the flat surface of the insulating body so that a direction of the signal lines is tilted to a direction of the first or second fibers at an angle which is determined based on board-cutting efficiency of the insulating body and a predetermined delay-time difference between the signal lines.

Abstract: A technique is provided for improvement in convenience and in cost reduction of a fixing part of a printed board unit. A printed board unit includes a plurality printed board including a first printed board and a second printed board; and at least one fixing part, interposed between the first printed board and the second printed board, fixing the first printed board and the second printed board such that the first printed board and the second printed board overlap and keep a predetermined space between the first printed board and the second printed board, and the fixing part variably determines the predetermined space.