The present invention provides a manufacturing method of a curved circuit board which includes the following steps. The first step is to provide a flexible substrate. The next step is to form a patterned catalyst layer on the flexible substrate. The next step is to deposit metal on the patterned catalyst layer by electroless plating to form a wiring substrate, wherein the wiring substrate includes a planar wiring structure. The last step is to place the wiring substrate into a mold having a molding surface with a three-dimensional design, and then execute a heating process to shape the planar wiring structure to a three-dimensional wiring structure, wherein the heated wiring substrate is laminated to the molding surface of the mold. The present invention further provides an electronic product using the curved circuit board.

A circuit board includes a plurality of first insulating base materials and a plurality of second insulating base materials that are alternately laminated, a first metal layer being formed into a pattern shape on a first surface of the first insulating base material, and a second metal layer being formed into a pattern shape on a second surface of the first insulating base material. The first metal layer is formed into a trapezoidal shape that is large in diameter on a first surface side of the first insulating base material. The second metal layer is formed into a trapezoidal shape that is large in diameter on a second surface side of the first insulating base material. The first metal layers and the second metal layers are laminated in such a manner that the trapezoidal shapes are alternately oriented.

A multilayer substrate includes a flexible element assembly including a principal surface, a first to an n-th external electrode disposed on the principal surface, and at least one first dummy conductor disposed inside the element assembly and being in a floating state. When the element assembly is viewed from a normal direction that is normal to the principal surface, a distance between an m-th external electrode and a nearest external electrode therefrom among the first to the n-th external electrodes is defined as a distance Dm, an average of distances D1 to Dn is defined as an average Dave, and when the element assembly is viewed from the normal direction, an area within a circle with a center on the m-th external electrode and with a radius of Dm is defined as an area Am. The first dummy conductor is located in at least one area Am with a radius of Dm smaller than the average Dave when viewed from the normal direction.

A composite circuit board includes a composite circuit board unit, a first solder mask formed on a first metal protection layer of the composite circuit board unit, and a second solder mask formed on a second metal protection layer of the composite circuit board unit. Two ends of a first outer conductive circuit are bent back toward each other and spaced apart a predetermined distance to form a first window. Two ends of a second outer conductive circuit are bent back toward each other and spaced apart a predetermined distance to form a second window.

A flexible circuit board includes two first wiring boards, a first adhesive, and a first conductive structure. Each of the two first wiring boards includes a first bent portion, and two first bent portions of the two wiring boards is connected to each other. The first adhesive layer is sandwiched between the two first bent portions. The first conductive structure penetrates the two first bent portions and the first adhesive layer and electrically connects the two first bent portions.

A press pad for use in lamination of multi-layer circuit boards is disclosed. The press pad includes: a planar pad having a first surface and a second surface opposite to the first surface; and a sheet of release film coupled to the first surface, wherein the release film sheet is coupled to the first surface using an acrylic-based adhesive containing thermoplastic polyolefin and methyl acrylate, and wherein the release film sheet comprises polyimide-based film.

Disclosed is a wiring substrate 1 including a stretchable resin layer 3 and a conductor foil or conductor plating film 5 which is provided on the stretchable resin layer 3 and forms a wiring pattern.

A transmission circuit board includes a bendable area, a first transmission areas, and a second transmission areas. The first and second transmission areas are connected to the bendable area. The inner circuit substrate board further includes a substrate layer and an inner circuit layer formed on the substrate layer and including a first signal circuit. The transmission circuit board further includes a first dielectric layer formed on the inner circuit layer, a first outer circuit layer formed on the first dielectric layer, a first protecting layer formed on the first outer circuit layer, and a first shielding layer formed on the first protecting layer. The first dielectric layer lies the first and second transmission areas. Two ends of the first signal circuit are connected to the first outer circuit layer. The first shielding layer is connected to the first outer circuit layer and lies the bendable area.

Provided are circuit board excellent in interlayer adhesion and solder heat resistance, and production method thereof. The circuit board is produced by a method including: preparing a plurality of at least one kind of thermoplastic liquid crystal polymer (TLCP) films, forming a conductor layer on one side or both sides of a film in at least one of the films to obtain a unit circuit board, laminating the films containing the unit circuit board to obtain a stacked material, conducting thermo-compression-bonding of the stacked material under pressurization to a first temperature giving an interlayer adhesion to integrate the stacked material, carrying out structure-controlling thermal treatment by heating the integrated stacked material at a second temperature which is lower than the first temperature and is lower than a melting point of a TLCP having a lowest melting point out of the plurality of TLCP films.

Epoxy adhesive comprising graphene sheets and at least one epoxy resin and articles made therefrom.