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 method of manufacturing a printed wiring board. A printed wiring board having a substrate and a circuit pattern formed thereon is provided. At least one through-hole is formed in the substrate. A plurality of fine wires are inserted into the through-hole, and a molten solder is filled into the through-hole by a capillary action due to small gaps formed between the fine wires. A multilayer printed wiring board may be provided comprising a plurality of wiring board layers each having a substrate and a respective circuit pattern formed thereon. The molten solder filled in the through-hole electrically connects at lest two of the respective circuit patterns. The plurality of fine wires may be disposed in a conductive hollow tubular body which is inserted along with the fine wires into the through-hole. Also, the plurality of fine wires may be arranged as a mesh sheet that is formed into a tubular body and inserted into the through-hole.

Abstract: The method for manufacturing the printed wiring board having a shield layer of the present invention is characterized in that, in a method for manufacturing a printed wiring board wherein a printed wiring circuit is provided on one or both sides of an insulating board and a shield layer is provided on the printed wiring circuit through an insulating layer, a shield layer and an earth circuit are formed on the insulating layer while injecting under pressure a coating for shield from a filling nozzle through a mask.

Abstract: A printed wiring board having a shielding layer for use in an integrated circuit is disclosed. The printed wiring board comprises an insulating sheet having a connecting through hole portion, a printed wiring circuit provided on one or both surfaces of the insulating sheet, an insulating layer having a thickness of 20.about.50 .mu.m which is provided on the printed wiring circuit, and an electromagnetic shielding layer provided on the insulating layer.

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 method of packing filler into through-holes in a printed circuit board is disclosed. The method comprises steps of packing the filler through a mask into the through-holes and at the same time smoothing protrusions of the filler at the upper and lower openings of the through-holes by means of squeegees. In this method, the mask may be a silk screen provided with open-worked packing holes for packing the filler in the positions corresponding to those in which the through-holes of said printed circuit board are packed. In the above method, the filler may be packed by delivering pressurized filler from a packing nozzle, which comprises 1) a packing means connected both to a manipulation means for actuating a delivery valve for delivering the filler from said nozzle tip and to a supply means for supplying the filler and 2) a nozzle tip attached to the delivery end of said packing nozzle. In the above-described method, said filler may be a solvent-less filler.

Abstract: A printed wiring board has a substrate having an outer peripheral edge. A printed circuit is formed on at least one side of the substrate. A shock-absorbing band formed of copper foil is disposed along at least a portion of the outer peripheral edge of at least one side of the substrate and is effective to absorb at least some of the impact applied to the printed wiring board during cutting thereof.

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: Method to form a photosensitive ink film having an even thickness over the entire surface of a broad plate material capable of obtaining a multiplicity of printed wiring boards. An emulsion pattern 4 is provided on a screen 3 on which a squeegee travels. The pattern 4 is formed correspondingly to a cutting spaces of a plate material for the purpose of obtaining a multiplicity of printed wiring boards. When a photosensitive ink is forced onto the broad plate material through a screen 3 for a screen printing, the photosensitive ink is dispersed by the pattern 4, thereby forming a film of even thickness over the entire surface of the plate material not corresponding to the emulsion pattern.

Abstract: A printed wiring board for forming an electric connection to an external device. The printed wiring board comprises a base material, and at least one connecting terminal formed on the base material for forming an electrical connection to an external device. A solder resist layer is formed on at least a portion of the base material surface excluding a connecting terminal forming region. A conductive protective layer is formed over the connecting terminal forming region and covers the connecting terminal. The end portion of the solder resist layer is separated from the end portion of the conductive protecting layer. An overcoat layer is formed on the separating portion for bridging the end portion of the solder resist layer and the end portion of the conductive protecting layer.

Abstract: In a method of manufacturing printed circuit boards by coating a flux preventive film for preventing a flux from rising on a component surface of an insulation board, the method of manufacturing printed circuit boards according to the present invention is characterized in that said method comprises the steps of printing white blank marks, white blank symbols and white blank letters corresponding to symbol marks, other symbols and letters on the component side surface of said insulation board before coating said flux preventive film, and then coating said flux preventive film of a transparent or translucent material on the printed surface.

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 method of forming an insulating layer on a printed circuit board for use in a manufacture of the printed circuit board is disclosed. The method comprises steps of providing a base material plate for the printed circuit board, forming a circuit pattern on the base material plate, providing an insulating layer on the circuit pattern, providing a conducting circuit on the insulating layer, and forming the insulating layer by a dry film.

Abstract: A method of manufacturing a printed circuit comprising the following steps: in a connection portion of a printed circuit formed on an insulating substrate, another circuit portion such as a jumper circuit is applied with resin ink; and a connection circuit for the circuit terminal portion of said printed circuit is formed by applying electroconductive ink.

Abstract: A printed wiring board having a shielding layer for use in an integrated circuit is disclosed. The printed wiring board comprises an insulating sheet having a connecting through hole portion, a printed wiring circuit provided on one or both surfaces of the insulating sheet, an insulating layer having a thickness of 20.about.50 .mu.m which is provided on the printed wiring circuit, and an electromagnetic shielding layer provided on the insulating layer.

Abstract: A method of manufacturing a printed circuit board comprises providing an insulating substrate having opposed major sides, forming a through-hole between the two sides of the insulating substrate, forming a conductive land on both sides of the insulating substrate surrounding the ends of the through-hole, forming margining frames at the outer peripheries of the conductive lands, and packing conductive paste into the through-hole after the formation of the margining frames. The margining frames extend vertically beyond the height of the conductive lands and prevent the conductive paste from spreading outwardly beyond the outer peripheries of the conductive lands.

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: In the method for forming through-holes of the present invention, by injecting a conductive material into the through-holes by means of a filling nozzle while removing the excessive conductive material with a squeegee, the filling can quickly and uniformly be performed independently of the board thickness of the substrate and the number and diameter of the through-holes.

Abstract: An etching method of forming circuit patterns on a printed circuit board is disclosed. The etching method comprises step of supplying etching solvent with discharge pressure of substantially 5.about.10 kg/cm.sup.2 and discharge particle diameter of 100.about.200 .mu.m.