Abstract: A valve spring includes a nitrided layer, and a core portion that is further inward than the nitrided layer. A chemical composition of the core portion consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr: 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Ca: 0.0001 to 0.0050%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, and N: 0.0070% or less, with the balance being Fe and impurities. In the core portion, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 per ?m2, and in the core portion, a numerical proportion of Ca sulfides with respect to a total number of oxide-based inclusions and sulfide-based inclusions is 0.20% or less.

Abstract: A method for manufacturing a wiring substrate includes preparing a substrate including an insulating layer and metal foils, forming a through hole in the substrate to penetrate through the insulating layer and foils, forming a first plating film on the substrate such that the first film is formed on the entire surface of each metal foil and the inner wall of the hole, laminating one or more resin sheets on the first film such that the resin sheet or sheets cover the first film on the entire surface of a respective one of the foils, pressing the resin sheet or sheets such that resin is extruded from the resin sheet or sheets into the hole and fills space surrounded by the first film inside the hole, removing the resin sheet or sheets, and forming a second plating film on the substrate to cover surface of the resin in the hole.

Abstract: A combined wiring board includes a metal frame having multiple opening portions, and multiple wiring boards accommodated in the opening portions in the metal frame, respectively. The opening portions in the metal frame have side walls having holding portions such that the holding portions hold the wiring boards in the opening portions in the metal frame, and the metal frame has slit portions adjacent to the holding portions and connecting portions connecting the slit portions to the opening portions.

Abstract: A method for manufacturing a combined wiring board includes preparing multiple wiring boards, preparing a metal frame having opening portions which accommodate the boards, respectively, positioning the boards in the opening portions of the frame, respectively, and forming multiple crimped portions in the frame by plastic deformation such that the sidewalls of the boards bond to sidewalls of the opening portions in the frame. The preparing of the boards includes forming the sidewalls of the boards such that when the boards are positioned in the opening portions of the frame, the sidewalls of the boards form wide-space portions and narrow-space portions with respect to the sidewalls of the opening portions in the frame, and the forming of the crimped portions includes generating the deformation such that the sidewalls of the opening portions in the frame abut the narrow-space portions of the boards before the wide-space portions of the boards.

Abstract: A wiring board includes an insulating substrate, a first conductor layer laminated on a first side of the insulating substrate, a second conductor layer laminated on a second side of the insulating substrate, first plating posts fitted in through holes in the insulating substrate respectively such that the first plating posts are projecting from the first conductor layer, and plating connecting parts connecting the second conductor layer and the first plating posts and having electronic component connecting portions such that the electronic component connecting portions form an electronic component mounting part positioned to mount an electronic component and are positioned on the through holes, respectively.

Abstract: A flex-rigid wiring board includes a flexible substrate, a first non-flexible substrate positioned on a first side of the flexible substrate, a second non-flexible substrate positioned on a second side of the flexible substrate, a first insulation layer laminated on first surfaces of the flexible substrate and first and second non-flexible substrates, and a second insulation layer laminated on second surfaces of the flexible substrate and first and second non-flexible substrates. Each of the first and second insulation layers has an opening portion exposing a portion of the flexible substrate such that the portion of the flexible substrate forms a flexible section connecting non-flexible rigid sections, and the first and second non-flexible substrates include a heat dissipating portion including a heat dissipating material having thermal conductivity which is higher than thermal conductivity of the first and second insulation layers.

Abstract: A wiring board includes an insulating substrate, a first conductor layer laminated on a first side of the insulating substrate, a second conductor layer laminated on a second side of the insulating substrate, first plating posts fitted in through holes in the insulating substrate respectively such that the first plating posts are projecting from the first conductor layer, and plating connecting parts connecting the second conductor layer and the first plating posts and having electronic component connecting portions such that the electronic component connecting portions form an electronic component mounting part positioned to mount an electronic component and are positioned on the through holes, respectively.

Abstract: A method for manufacturing a combined wiring board includes preparing wiring boards, preparing a metal frame having opening portions formed to accommodate the wiring boards, respectively, positioning the wiring boards in the opening portions in the metal frame, and forming crimped portions in the metal frame by plastic deformation such that sidewalls of the metal frame in the opening portions bond sidewalls of each of the wiring boards. The crimped portions are formed such that the crimped portions in the metal frame have amounts of the plastic deformation which are set different for positions of the crimped portions in the metal frame.

Abstract: A combined wiring board has multiple piece components each including a wiring board, and a frame component having an accommodation opening portion and holding the multiple piece components in the accommodation opening portion such that each of the piece components is fixed to the frame component at an outer rim of each of the piece components. The frame component has a thermal expansion coefficient in a planar direction which is set higher than a thermal expansion coefficient of the multiple piece components in the planar direction.

Abstract: A method for manufacturing a combined wiring board includes providing a metal frame having an accommodation opening portion, positioning a wiring board in the accommodation opening portion of the metal frame, and subjecting the metal frame to plastic deformation such that a sidewall of the wiring board is connected to a sidewall of the metal frame inside the accommodation opening portion of the metal frame.

Abstract: A flex-rigid wiring board includes a flexible substrate, a non-flexible substrate positioned such that the non-flexible substrate is extending in horizontal direction of the flexible substrate, a first wiring layer formed on first surfaces of the flexible and non-flexible substrates, a second wiring layer embedded in second surfaces of the flexible and non-flexible substrates, a first insulating layer covering the first surfaces of the flexible and non-flexible substrates and having an opening exposing a portion of the first surface of the flexible substrate, and a second insulating layer covering the second surfaces of the flexible and non-flexible substrates and having an opening exposing a portion of the second surface of the flexible substrate. The first wiring layer includes non-embedded wirings on the first surfaces of the flexible and non-flexible substrates, and the second wiring layer includes embedded wirings in the second surfaces of the flexible and non-flexible substrates.

Abstract: A wiring board includes multiple insulating layers including first, second, third, fourth and fifth insulation layers laminated in the order of the first, second, third, fourth and fifth insulation layers. The first insulation layer has a first conductor including plating, the second insulation layer has a second conductor including plating, the third insulation layer has a third conductor including conductive paste, the fourth insulation layer has a fourth conductor including plating, the fifth insulation layer has a fifth conductor including plating, and the first conductor, the second conductor, the third conductor, the fourth conductor and the fifth conductor are formed along the same axis and are electrically continuous with each other.

Abstract: A plug-in board replacement method includes preparing a board having a piece board, forming first conductive pattern on first surface of the board, forming second conductive pattern on second surface on the opposite side such that the second pattern is on the opposite side of the first pattern, irradiating laser upon the first and second surfaces along the first and second patterns such that the piece is cut out from the board, and fitting the piece into another board. The irradiating includes irradiating laser upon the first surface along the first pattern such that laser is irradiated along the border between edge portion of the first pattern and the first surface and laser upon the second surface along the second pattern such that laser is irradiated along the border between edge portion of the second pattern and the second surface such that the piece is cut out through the board.

Abstract: A flex-rigid wiring board includes a flexible substrate, a first non-flexible substrate positioned on a first side of the flexible substrate, a second non-flexible substrate positioned on a second side of the flexible substrate, a first insulation layer laminated on first surfaces of the flexible substrate and first and second non-flexible substrates, and a second insulation layer laminated on second surfaces of the flexible substrate and first and second non-flexible substrates. Each of the first and second insulation layers has an opening portion exposing a portion of the flexible substrate such that the portion of the flexible substrate forms a flexible section connecting non-flexible rigid sections, and the first and second non-flexible substrates include a heat dissipating portion including a heat dissipating material having thermal conductivity which is higher than thermal conductivity of the first and second insulation layers.

Abstract: A flex-rigid wiring board includes a flexible base material structure, a rigid base material structure extending from opposite ends of the flexible base material structure, an electronic component embedded in the rigid base material structure, a first buildup layer laminated on first surfaces of the flexible base material structure and rigid base material structure and having an exposing portion exposing the flexible base material structure, and a second buildup layer laminated on second surfaces of the flexible base material structure and rigid base material structure and having an exposing portion exposing the flexible base material structure. The first and second buildup layers are formed such that the flexible base material structure exposed by the exposing portions of the first and second buildup layers forms a bendable portion and that the rigid base material structure and the first and second buildup layers form non-bendable portions connected to the bendable portion.

Abstract: A combined wiring board includes multiple wiring boards, and a connected metal frame having multiple metal frames and one or more connecting portions such that the metal frames are connected each other by the connecting portion or connecting portions and have accommodation opening portions formed to accommodate the wiring boards, respectively.

Abstract: A combined wiring board includes a wiring board set having multiple wiring boards and one or more adhesive agent portions such that the wiring boards are connected each other by the adhesive agent portion or adhesive agent portions, and a metal frame having an accommodation opening portion formed to accommodate the wiring board set such that the wiring board set is positioned in the accommodation opening portion of the metal frame.

Abstract: A method of manufacturing a flex-rigid wiring board includes positioning a flexible board and a non-flexible substrate adjacent to each other, forming a metal layer over the flexible board such that the metal layer is formed to stop laser irradiation from reaching into the flexible board, forming an insulating layer such that the insulating layer covers the metal layer, the flexible board and the non-flexible substrate, irradiating laser upon the insulating layer such that a portion of the insulating layer covering the metal layer is cut; and removing the portion of the insulating layer covering the metal layer from the flexible board such that at least a portion of the flexible board is exposed.

Abstract: A method for manufacturing a multi-piece substrate includes preparing a first frame having a connecting portion to which a first piece substrate is to be connected, forming on a portion of the first piece substrate connected to a second frame a conductive pattern having a contour corresponding to the periphery of the connecting portion of the first frame, irradiating laser along the boundary between the second frame and the conductive pattern on the first piece substrate such that the first piece substrate having a joint portion which engages with the connecting portion of the first frame is detached from the second frame, and fitting the joint portion of the first piece substrate into the connecting portion of the first frame such that the first piece substrate is connected to the first frame.

Abstract: A combined wiring board includes multiple metal frames arrayed in a first direction, and multiple wiring boards bonded to the metal frames such that the wiring boards are arrayed in the first direction. The metal frames directly or indirectly engage with the wiring boards such that each of the metal frames is positioned between two adjacent wiring boards of the wiring boards.