Abstract: A covering film (100) includes a first covering layer (10), a first adhesive layer (20), and a thermal conductive layer (30) sandwiched between the first covering layer (10) and the first adhesive layer (20). A thermal conductivity of the thermal conductive layer (30) is K1, K1=3˜65 W/m.K. A thermal conductivity of the first covering layer (10) is K2, K2=0.02˜3.0 W/m.K. A thermal conductivity of the first adhesive layer (20) is K3, K3=0.02˜1.0 W/m.K. A circuit board and its manufacturing method are also provided.

Abstract: A printed circuit board used as a voice coil includes N board units stacked over one another, each board unit having a first electrically connecting region and a second electrically connecting region, all of the first electrically connecting regions being stacked over one another, all of the second electrically connecting regions being stacked over one another, each board unit having a first circuit structure, a base, and a second circuit structure arranged from top to bottom, in each two adjacent board units, the first electrically connecting region of the second circuit structure of an upper board unit being electrically connected in series with the first electrically connecting region of the first circuit structure of a lower board unit, in each board unit, the first circuit structure being electrically connected in series with the second circuit structure in the second electrically connecting region.

Abstract: The present disclosure relates to a flexible circuit board. The flexible circuit board includes a first conductive trace substrate and a third conductive layer, a second conductive post and a third conductive post. The first conductive trace substrate includes a first insulating layer, a first conductive layer and a second conductive layer formed two opposite surfaces of the first insulating layer. The first conductive layer includes a first signal line, the second conductive layer includes a second signal line, and the first signal line is parallel connected with the second signal line.

Abstract: A printed circuit board used as a voice coil includes N board units stacked over one another, each board unit having a first electrically connecting region and a second electrically connecting region, all of the first electrically connecting regions being stacked over one another, all of the second electrically connecting regions being stacked over one another, each board unit having a first circuit structure, a base, and a second circuit structure arranged from top to bottom, in each two adjacent board units, the first electrically connecting region of the second circuit structure of an upper board unit being electrically connected in series with the first electrically connecting region of the first circuit structure of a lower board unit, in each board unit, the first circuit structure being electrically connected in series with the second circuit structure in the second electrically connecting region.

Abstract: A printed circuit board includes a first printed circuit substrate and a second printed circuit substrate. The first printed circuit substrate includes a substrate layer and a first conductive circuit layer. The first conductive circuit layer is formed on the substrate layer. The substrate layer includes at least two first grooves. The first conductive circuit layer includes at least one signal wire. The first grooves are defined in both sides of the signal wire. The second printed circuit substrate is formed on the first printed circuit substrate. The second circuit substrate includes a third copper layer. A second groove is defined in the third copper layer. The first grooves are opposite to the second groove. The first grooves and the second groove form a space.

Abstract: A printed circuit board includes a first printed circuit substrate and a second printed circuit substrate. The first printed circuit substrate includes a substrate layer and a first conductive circuit layer. The first conductive circuit layer is formed on the substrate layer. The substrate layer includes at least two first grooves. The first conductive circuit layer includes at least one signal wire. The first grooves are defined in both sides of the signal wire. The second printed circuit substrate is formed on the first printed circuit substrate. The second circuit substrate includes a third copper layer. A second groove is defined in the third copper layer. The first grooves are opposite to the second groove. The first grooves and the second groove form a space.

Abstract: A printed circuit board includes a first printed circuit substrate and a second printed circuit substrate. The first printed circuit substrate includes a substrate layer and a first conductive circuit layer. The first conductive circuit layer is formed on the substrate layer. The substrate layer includes at least two first grooves. The first conductive circuit layer includes at least one signal wire. The first grooves are defined in both sides of the signal wire. The second printed circuit substrate is formed on the first printed circuit substrate. The second circuit substrate includes a third copper layer. A second groove is defined in the third copper layer. The first grooves are opposite to the second groove. The first grooves and the second groove form a space. The signal wire is surrounded by air in the space. A method for manufacturing the printed circuit board is also provided.

Abstract: A printed circuit board includes a first printed circuit substrate and a second printed circuit substrate. The first printed circuit substrate includes a substrate layer and a first conductive circuit layer. The first conductive circuit layer is formed on the substrate layer. The substrate layer includes at least two first grooves. The first conductive circuit layer includes at least one signal wire. The first grooves are defined in both sides of the signal wire. The second printed circuit substrate is formed on the first printed circuit substrate. The second circuit substrate includes a third copper layer. A second groove is defined in the third copper layer. The first grooves are opposite to the second groove. The first grooves and the second groove form a space. The signal wire is surrounded by air in the space. A method for manufacturing the printed circuit board is also provided.

Abstract: A PCB includes at least three single layer circuit boards laminated together. The single layer circuit boards include two outer circuit boards and at least one inner circuit board. Each single layer circuit board includes a dielectric layer and a conductive layer on a surface of the dielectric layer. The dielectric layer is selected from a material of thermoplastic resin. Each single layer circuit board defines at least one blind hole passing through the dielectric layer and is ended at the conductive layer. Each blind hole is filled with a filler material electrically connected to the conductive layer. The conductive layer of the at least one inner circuit board forms a first conductive circuit pattern, and the conductive layers of the outer circuit boards each form a second conductive circuit pattern. The second conductive circuit pattern is electrically connected to the first conductive circuit pattern by the filler material.