Nitto-denko Corporation

Nitto Electric Industrial Co., Ltd.

Toshihiko Sugimoto

Chiharu Miyaake

Yasufumi Miyake

Suguru Yamamoto

Yousuke Miki

Mitsuru Honjo

Ikuo Kawamoto

Kenkichi Yagura

Yuichi Takayoshi

Yozo Oishi

Tetsuya Terada

Seiichi Watanabe

Fuyuki Eriguchi

Masaaki Kawaguchi

Takahiko Moriuchi

Yasuo Nakatsuka

Yosuke Miki

Zenichi Ueda

Shiyouzou Kawazoe

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

A flexible wiring board including a gold pad having dynamic Vickers hardness of not less than 50 or having a ratio of amount of nickel in a surface of the gold pad (atomic weight %) to thickness of gold (&mgr;m) of not more than 5 or having both the dynamic Vickers hardness of not less than 50 and the ratio of amount of nickel in the surface of the gold pad (atomic weight %) to thickness of gold (&mgr;m) of not more than 5, to provide a flexible wiring board that can substantially ensure the connection reliability when the board is connected with a semiconductor device by wiring bonding.

Flexible wiring board

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 flexible printed circuit comprising a plastic film and a conducting layer, wherein the plastic film exhibits a heat shrinkage rate ellipse having an eccentricity of not more than 0.7 and preferably exhibits an ultrasonic wave propagation rate ellipse having an eccentricity of not more than 0.4 and a polarized microwave transmission intensity ellipse having an eccentricity of not more than 0.55. The flexible printed circuit has improved dimensional accuracy owing to the dimensional stability of the plastic film.

Flexible printed circuit and process for producing the same

A raw material plastic film like a band stretched in two directions with a machine direction as a longitudinal direction of stretch and a transverse direction as a lateral direction of stretch is prepared. One standard line parallel with the machine direction of stretch is assumed on a film face of the raw material plastic film. An area due to cut a cover layer plastic film and an area due to cut a base layer plastic film (the two areas are of almost the same shape) are assumed to be on the standard line in a state in which the areas are aligned in orientation. However, both an arbitrary point of the area due to cut and the point of the area due to cut corresponding thereto need to be on the standard line. A cover layer plastic film and a base layer plastic film are cut out from the two areas due to cut. Metal electric circuit is formed on a surface of the base layer plastic film via an adhesive layer. The metal electric circuit has a plastic deformation component of 0.0003 (mm/mm) or more when a stress load is imposed until strain becomes 0.002 (mm/mm), and then removed. The cover layer plastic film is stuck on the metal electric circuit via an adhesive layer with the rear face of the plastic film facing the surface of the base layer plastic film, thereby manufacturing a flexible printed circuit.

Flexible printed circuit

A composite sheet comprises a first resin film; and a second resin film laminated on the first resin film; wherein two ellipses of coefficient of linear expansion are created on polar coordinates in corresponding parts of the first and second resin films by a predetermined method and the two ellipse are overlapped so as to match in the center point and coordinate axes X and Y, and the maximum value of a linear expansion coefficient difference between the two resin films is equal to or less than a predetermined value.

Flexible printed circuit and manufacturing method therefor

A reinforcement for a flexible printed circuit board, which can sufficiently prevent the flexible printed circuit board thus reinforced from being warped when heated during the assembly process of electronic components or other procedures. The reinforcement according to the present invention is used to adhere to a flexible printed circuit board 1. The reinforcement according to the present invention comprises an internal material 21 having a bending neutral surface at the center of the thickness thereof, and an external material 22 having the same Young's modulus as that of an insulating substrate 11 of the flexible printed circuit board 1, bonded to one side of the internal material 21. The other side of the internal material 21 acts as an adhesive surface to the flexible printed circuit board 1.

Reinforcement for flexible printed circuit board and reinforced flexible

A liquid crystal display plastic cell structure free of deviation in position of electrode patterns comprising:

Liquid crystal display plastic cell structure

A polarizing plate is disclosed, comprising a polarizing film and a protective layer bonded through an adhesive layer to at least one surface of the polarizing film, wherein the protective layer is a polyester film in which the minimum or maximum refractive index in a direction in parallel with the plane of the film is nearly equal to that in the direction of the film thickness and the retardation is at least 10 .mu.m. On this polarizing plate, colored interference fringes are not formed at all even if it is looked at from any direction. Thus, the polarizing plate is suitable for use in the circumstance that it is exposed to the air, or in a display wherein a liquid crystal is used.

Polarizing plate

A product with a compound membrane which comprises a molded substrate, a metal membrane having an average thickness equal to or less than the maximum surface roughness of the molded substrate on the molded substrate and a dielectric membrane having a thickness of 100 .ANG. or more on the metal membrane.

Growing community of inventors

Osaka, Japan

Toshihiko Sugimoto