Abstract: A printed wiring board comprises a substrate, a printed wiring circuit formed on the substrate, and insulating layer formed on the printed wiring circuit, an electromagnetic wave shielding layer provided on the insulating layer, and an overcoat layer provided on the electromagnetic shielding layer. The electromagnetic shielding layer has a first color, and the overcoat layer has a second color different from the first color. The color of the overcoat layer may be any color which is easily visually distinguishable from the color of the electromagnetic wave shielding layer so that visual inspection of the working condition of the overcoat layer is facilitated.

Abstract: A printed wiring board includes an insulating substrate having a wiring circuit formed on at least one side thereof. An insulating layer is formed on the wiring circuit and has a plurality of individual curved openings extending therethrough to expose corresponding connection lands of a ground circuit of the wiring circuit. An electromagnetic wave shielding layer is formed on the insulating layer over a portion of the wiring circuit and electrically and mechanically connects with the ground circuit through the connection lands. The curved openings are circular, elliptical or similar shape and dimensioned to prevent formation of bubbles when forming the electromagnetic wave shielding layer thereby enhancing the electrical and mechanical connection between the electromagnetic wave shielding layer and the planar connection land. The curved openings also prevent thinning of the wave shielding layer at the connection lands so as to prevent an increase in connection resistance.

Abstract: A printed wiring board includes a substrate having an electrically conductive pattern disposed on at least one side of the substrate. An electrically conductive through-hole is formed in the substrate. At least one of a solder resist film and an electromagnetic shielding layer undercoat film are disposed over the conductive pattern but do not cover the electrically conductive through-hole. An ink layer is formed over at least one end of the electrically conductive through-hole. A method of manufacturing the printed wiring board embodied by the invention comprises providing a substrate having an electrically conductive through-hole. A conductive pattern is formed on at least one side of the substrate. At least one of a solder resist film and an electromagnetic shielding layer undercoat film are formed over the conductive pattern but not over the electrically conductive through-hole. An ink layer is formed over at least one end of the electrically conductive through-hole.

Abstract: A printed wiring board shielded from electromagnetic wave radiation has a conductive circuit pattern formed on an insulating substrate, a first insulating layer disposed over the circuit pattern, a jumper wire formed over the first insulating layer and between connecting terminals of the conductive pattern, a second insulating layer covering the jumper wire and the first insulating layer, and an electromagnetic wave shielding layer disposed over the conductive pattern. The jumper wire is formed by printing using a conductive paste containing a conductive material such as silver, carbon or copper. The shield layer is formed by printing using a conductive metal resin paste such as copper. An overcoat layer is applied over the shield layer to protect the shield layer.

Abstract: A printed-wiring board shielded from electromagnetic wave radiation is made by forming a conductive circuit pattern on an insulating substrate, disposing a first insulating layer over the circuit pattern, forming a jumper wire over the first insulating layer and between connecting terminals of the conductive pattern, forming a second insulating layer covering the jumper wire and the first insulating layer, and disposing an electromagnetic wave shielding layer over the conductive pattern. The jumper wire is formed by a printing process using a conductive paste containing a conductive metal such as silver, carbon or copper. The shield layer is formed by a printing process using a conductive metal resin paste such as copper. The shield layer is protected by providing an overcoat layer over the shield layer.

Abstract: A printed wiring board has an electromagnetic wave shielding layer. The printed wiring board includes a printed circuit formed on a substrate. Stratified layers of insulation are formed over the printed circuit. The insulation layers are disposed so as to form a bowl-shaped connection region. A terminal may be formed simultaneously with the forming of the electromagnetic wave shielding layer to provide a connection between the electromagnetic shielding layer and the printed circuit. The bowl-shaped connecting region provides for smoothly filling the terminal with a conductor paste without the occurrence of foaming or blurring during, for example, a silk screening printing process.

Abstract: A method for connecting a ground circuit and an electromagnetic wave shielding layer for a printed wiring circuit in a printed circuit board is disclosed. The method comprising the steps of forming said insulating layer by a plurality of insulating layers and gradually increasing from the printed wiring circuit side to the electromagnetic wave shielding layer side, a diameter of an aperture of the ground circuit of each insulating layer in the process for forming the insulating layer.

Abstract: A method of manufacturing a printed circuit board comprises the steps of providing an insulating substrate for the printed circuit board, forming circuit patterns made of a conductive material on at least one side of the insulating substrate, forming an insulating layer on the circuit patterns, and adhering a cross-mesh shield layer onto at least a portion of the insulating layer in such a manner that a margin is placed both on the outer periphery of the insulating layer itself and around electric contacts such as lands and through-holes.

Abstract: A method of manufacturing a printed circuit board is disclosed. The method comprises steps of providing a substrate for the printed circuit board, forming circuit patterns on one or both sides of the substrate, and shielding the whole or a required part of the circuit patterns by using a shield layer in such a manner that the shield layer and a grounding circuit of the circuit patterns are connected through a resistor. This method of manufacturing a printed circuit board is improved so that adhesion between the shield layer and the junction land of the grounding circuit is enhanced by the joining of the shield layer to the junction land of the grounding circuit through the resistor, and that the noise preventive action of the shield layer is improved by the attenuating of electromagnetic-wave energy received by the shield layer which is to be discharged as electrical current to the grounding circuit.

Abstract: A printed wiring board having electromagnetic wave shielding layer for use in the integrated semiconductor circuit is disclosed. The printed wiring board comprises an insulating sheet, printed wiring circuits and grounded wiring circuit which are provided on one surface of the insulating sheet, an insulating layer provided on the surface of the insulating sheet, the printed wiring circuit and the grounded wiring circuit, an electromagnetic wave shielding layer provided on the insulating layer and having a portion contacted to the ground wiring circuit directly, and an over-coating layer provided on the electromagnetic wave shielding layer and having exposed portions placed over the contacted portion of the shielding layer.

Abstract: The invention relates to a printed wiring board (7) which includes at least one carbon resistor (3) formed across terminals (2a, 2b) of printed wiring circuit (2). A heat dissipating film layer (4) is formed at least on the carbon resistor (3). Thus, heat produced in the resistor (3) is effectively dissipated.