Abstract: Outer surface of a printed circuit board having circuit conductors on one or both surfaces may be covered by shield film or layer to shield outer noise from reaching the circuit conductors. To shield cross talk and noise from reaching each other, all electrically exposed surfaces of the circuit conductors are covered also by shield film.

Abstract: A printed circuit board comprises a base plate and a circuit conductor formed on at least one of the opposed surfaces of the base plate. A heat-radiating film is formed on at least a portion of the surface of the circuit conductor, and an insulating film is formed over the exposed surfaces of the heat-radiating film and the circuit conductor. At least one opening is formed in the insulating film, and the opening overlies the heat-radiating film thereby directly exposing the heat-radiating film to ambient atmosphere so as to promote dissipation of heat from the circuit conductor during use of the printed circuit board. The opening in the insulating film may be in the form of a slot or may comprise a pattern of circular or oval openings. The heat-radiating film may be copper or nickel paste, or non-organic material such as aluminum oxide.

Abstract: A printed wiring board includes a dielectric base plate, a circuit pattern at least on one surface of the base plate, and a solder resist film containing silicon series and/or fluorine series and covering the base plate except a desired soldering area of the circuit pattern. The solder resist film has solder repelling property to prevent bridging of solder across adjacent circuits. However, the solder repelling property apts to form dots on the solder resist film. Accordingly, at least one flux accumulating portion is formed on said one surface of the base plate to accumulate flux repelled by the solder resist film. The flux accumulating portion may be a recess and/or through-hole arranged on the surface of the solder resist film.