Abstract: A circuit board includes at least two substrates and an adhesive film sandwiched between the two substrates. Each substrate includes a base board. The base board includes conductive wires. Each base board is connected to the other base board by the adhesive film. The adhesive film includes two first adhesive layers and a second adhesive layer. The second adhesive layer is sandwiched between the two first adhesive layers. An adhesion force of the first adhesive layer is greater than an adhesion force of the second adhesive layer. A major composition of the second adhesive layer is rubber. The rubber is selected from a group consisting of isoprene rubber, styrene butadiene rubber, ethylene propylene rubber, butyl rubber, acrylic rubber, and polybutadiene rubber, and mixtures thereof.

Abstract: Disclosed is a method of fabricating a graphite sheet, including: polymerizing diamines and a dianhydride to form a polyamic acid. The polyamic acid is solvent casted on a substrate and hot baked to form a polyamic acid film or gel film. The polyamic acid film or gel film is biaxially stretched at a high temperature imidization or chemical imidization to form the polyimide film. The polyimide film is then carbonized and graphitized to form a graphite sheet. The diamines include a diamine of Formula 1 and a diamine of Formula 2, and the dianhydride includes a dianhydride of Formulae 3, Formula 4, Formula 5, Formula 6, Formula 7, Formula 8, Formula 9, or combinations thereof.

Abstract: Disclosed is a method of fabricating a graphite sheet, including: polymerizing diamines and a dianhydride to form a polyamic acid. The polyamic acid is solvent casted on a substrate and hot baked to form a polyamic acid film or gel film. The polyamic acid film or gel film is biaxially stretched at a high temperature imidization or chemical imidization to form the polyimide film. The polyimide film is then carbonized and graphitized to form a graphite sheet. The diamines include a diamine of Formula 1 and a diamine of Formula 2, and the dianhydride includes a dianhydride of Formulae 3, Formula 4, Formula 5, Formula 6, Formula 7, Formula 8, Formula 9, or combinations thereof.

Abstract: The present invention provides a cover film for a printed circuit board. The cover film includes an adhesive layer; a core layer made of a polymer; and a composite material layer formed on the core layer, comprising epoxy resin, a black material selected from the group consisting of a black pigment, carbon powder, nano carbon tube and a combination thereof, and an additive selected from the group consisting of titanium dioxide, boron nitride, barium sulfate and a combination thereof, wherein the core layer is disposed between the adhesive layer and the composite material layer, and the adhesive layer and the composite material layer have the same thickness or have a thickness difference being no more than 15 micro meters. The cover film of the preset invention is capable of shielding circuit patterns and has great folding endurance, and is thus applicable to flexible printed circuit boards.

Abstract: A double-sided copper foil substrate, which comprises: a polymer layer; a first copper foil; an adhesive layer formed on the polymer layer such that the polymer layer is sandwiched between the adhesive layer and the first copper layer; and a second copper foil causing the adhesive layer to be sandwiched between the second copper foil and the polymer layer, wherein the polymer layer and the adhesive layer have a total thickness of from 12 to 25 ?m. The present invention further provides a flexible printed circuit board structure utilizing the composite double-sided copper foil substrate of the present invention, wherein the second double-sided copper foil substrate has a trench for exposing a portion of the adhesive layer. The double-sided copper foil substrate of the present invention are lower in rebound and satisfying the demand for the greater number of bending and sliding cycles under a lower R angle, and particularly is suitable for thin and flexible electronic products.

Abstract: A double-sided copper foil substrate, which comprises: a polymer layer; a first copper foil; an adhesive layer formed on the polymer layer such that the polymer layer is sandwiched between the adhesive layer and the first copper layer; and a second copper foil causing the adhesive layer to be sandwiched between the second copper foil and the polymer layer, wherein the polymer layer and the adhesive layer have a total thickness of from 12 to 25 ?m. The present invention further provides a flexible printed circuit board structure utilizing the composite double-sided copper foil substrate of the present invention, wherein the second double-sided copper foil substrate has a trench for exposing a portion of the adhesive layer. The double-sided copper foil substrate of the present invention are lower in rebound and satisfying the demand for the greater number of bending and sliding cycles under a lower R angle, and particularly is suitable for thin and flexible electronic products.

Abstract: The present invention provides a cover film for a printed circuit board. The cover film includes an adhesive layer; a core layer made of a polymer; and a composite material layer formed on the core layer, comprising epoxy resin, a black material selected from the group consisting of a black pigment, carbon powder, nano carbon tube and a combination thereof, and an additive selected from the group consisting of titanium dioxide, boron nitride, barium sulfate and a combination thereof, wherein the core layer is disposed between the adhesive layer and the composite material layer, and the adhesive layer and the composite material layer have the same thickness or have a thickness difference being no more than 15 micro meters. The cover film of the preset invention is capable of shielding circuit patterns and has great folding endurance, and is thus applicable to flexible printed circuit boards.

Abstract: The present invention provides a cover layer for a printed circuit board. The cover layer includes a first polymer layer, a second polymer layer and a light-reflecting layer disposed between the first and second polymer layers and having a thickness being 0.5 to 10 micro meters. Due to the light-reflecting layer, the cover layer of the present invention has high reflection rate and great flexibility suitable for a flexible printed circuit board.