Nitto-Denko Corporation

Nitto Electric Industrial Co., Ltd.

Yasufumi Miyake

Takeshi Kakuhashi

Takashi Oda

Toshihiko Sugimoto

Chiharu Miyaake

Tadao Ohkawa

Tetsuya Terada

Kyouyuu Jo

Mitsuru Honjo

Ikuo Kawamoto

Kenkichi Yagura

Katsuhiko Yamaguchi

Akio Tsumura

Seiki Kobayashi

A wired circuit board having improved adhesion between the conductive pattern and an insulating layer to prevent a plating solution from remaining between a metal plating layer and the insulating layer. The invention prevents ionic impurities in the plating solution from remaining as residual or ionic contamination, thereby preventing a short circuit from developing when electric current flows through the circuit under a high temperature and high humidity environment. Lower end portions of the terminal portions that are formed on an insulating base layer and lower end portions of side surfaces and metal plating layers that cover the terminal portions are embedded in the insulating base layer in a flexible wired circuit board.

Method of producing a wired circuit board

Wired circuit board

The invention provides a process for producing a substrate for flexible circuit boards which comprises: providing a multilayered insulating resin layer comprising an insulating layer and an adhesive layer; and laminating a metal foil to the insulating layer of the multilayered insulating resin layer via the adhesive layer at a temperature not lower than the glass transition temperature of the insulating layer.

Process for producing substrate for flexible circuit board

Flexible printed circuit board with reinforcing plate

A flexible wiring board which exhibits a sufficient flex life under high temperature working conditions. The flexible wiring board comprises an insulation layer provided on both surfaces of a conductor layer, optionally with an adhesive layer provided interposed therebetween, wherein the layers being in direct contact with both surfaces of the conductor layer exhibit an average complex shear modulus value of from 1.0&times;10,to 4&times;10,dyn/cm,at a temperature of 60&deg; C. and a frequency of 25 Hz.

Flexible wiring board

After a flexible printed circuit is left under an atmosphere of a water vapor pressure of not lower than 30 mmHg so as to absorb moisture, a voltage is applied between two wiring portions to thereby measure an insulation resistance value between the wiring portions during the voltage application. The quantity &Dgr;log(R) of the change of the insulation resistance value at regular intervals is obtained. An examination is made as to whether the maximum of the quantity &Dgr;log(R) of the change of the insulation resistance value is not larger than a predetermined reference value or not. From this examination, a judgment is made as to whether the flexible printed circuit is good or not.

Method for inspecting a flexible printed circuit

The present invention provides a rigid circuit member obtained by bending a composite laminate comprising a circuit conductor made of a metal foil interposed between plastic films having an elastic modulus of not less than 450 kg/mm,with an adhesive, characterized in that as said plastic film there is used a polyethylene naphthalate film. The present invention also provides a circuit board adapted to be connected to a conductor on a rigid substrate, characterized in that said circuit conductor is interposed between polyethylene naphthalate films. The present invention further provides a printed circuit board, comprising a polyethylene naphthalate film having an elastic modulus of not less than 500 kg/mm,, not more than 1.5&times;10,/&deg; C., a hygroscopic expansion coefficient of not more than 1.2&times;10,/%RH, a water vapor permeability of not more than 15 g/m,/mil day, a percent water absorption of not more than 2% and a melting point of not higher than 280&deg; C. and a conductor circuit integrated into a laminate with an adhesive layer provided interposed therebetween.

Circuit member and circuit board

A polyester film for printed circuits to be used as a base in a printed circuit base plate or as a base and/or cover layer in a printed circuit board, which undergoes a degree of dimensional stability of not more than 1% in both the longitudinal and transverse directions when kept at 150.degree. C. for 30 minutes, and which is obtained by heat treating an extrusion molded and stretched polyester film at 150.degree. C. to 240.degree. C. without applying tension.

Polyester film for forming printed circuit

In a printed circuit substrate incorporating a resistor pattern film and a conductor pattern film are formed on the two surfaces of a high conductive material layer such as a copper foil, respectively, in a predetermined positional relationship, and an insulating support is combined directly or indirectly with the resistor pattern film on the high conductive material layer, whereby a printed circuit board with resistance elements having high performance can be manufactured, while the number of processing steps can be greatly reduced.

Printed circuit substrate with resistance elements

A printed circuit substrate with a resistance coat comprises an insulating support having provided at least on the one side thereof a highly conductive material layer interposed with a resistance coat. The resistance coat comprises tin-nickel alloy.

Growing community of inventors

Osaka, Japan

Yasufumi Miyake