Matsushita Electric Industrial Co., Ltd.

Masanaru Hasegawa

Hideo Hatanaka

Masahide Tsukamoto

Kazunori Sakamoto

Yukihiro Shimasaki

Yoshihiro Kawakita

Tomiharu Hosaka

Yusuke Ozaki

Akira Kisoda

Toshiyuki Kitagawa

Yoshiki Hayashi

Hiroshi Suzuki

Osamu Noda

Takeo Fusayama

Kazuhiko Kosuge

Kenji Hayashi

A method for producing printed wiring boards comprises the steps of perforating through holes at predetermined positions in an adhesive insulator sheet, filling the through holes with a conductive material such as a conductive paste or metal balls, transferring conductive wiring patterns that have been formed on surfaces of releasable supporting sheets onto the surfaces of the adhesive insulator sheet by heat and pressure. Simultaneously, interlayer via-connections are performed by means of the conductive material filled into the through holes.

Method for producing printed wiring boards

In a wiring board, predetermined wiring patterns which are formed on both sides of an insulation substrate are electrically connected by an electrically conductive material provided in through holes formed through the insulation substrate. The insulation substrate is composed of a resin impregnated fibrous sheet and a heat resistant film. The present invention solves the problems of the wiring board which are caused by irregularities on the surface of the resin impregnated fibrous sheet. The problems include insufficient adhesion strength between the wiring pattern and the insulation substrate or the limitation of fineness of the wiring pattern due to the irregularities on the surface of the printed wiring board which are formed upon the thermocompression bonding process.

Wiring board and a process of producing a wiring board

A printed wiring board includes at least one insulator sheet having through holes filled with conductive material and a conductive wiring pattern. The wiring pattern is embedded in the insulator sheet so that an upper surface of the wiring pattern and surrounding portions of the insulator sheet form a flat surface. The insulator sheet may be made from a glass-epoxy prepreg or of a polyester or polyimide sheet coated with an adhesive or glue. The wiring pattern can be transferred to the insulator sheet from a surface of a releasable supporting sheet.

Printed wiring board

A conductive paste having excellent printing properties, which can be used for manufacturing heat-resistant conductors and resistive elements, is described. Such a conductive paste can be obtained by preparing as a binder a polyimide precursor whose weight average degree of polymerization (n) ranges from 5 to 20, and mixing it with a solvent and a conductive powder. The polyimide precursor preferably is included in the range from 50 to 80 weight parts to 100 weight parts of the solvent. A polar solvent, or a mixed solvent including a polar solvent and a nonpolar solvent can be used. A preferable mixed solvent is a mixture of N-methyl-2-pyrrolidone and diethylene glycol dimethyl ether, in which the mixing volume ratio is preferably ranging from 2:8 to 9:1, more preferably, 2:8 to 3:7.

Conductive paste

To address the problem of difficulty of making compatible flame retarding property and electrical and mechanical characteristics in conventional printed interconnection substrates, the present invention employs, in a substrate for printed circuit board of which the insulating material comprises a thermosetting resin composition comprising an epoxy resin main component and a curing agent, an epoxy resin containing a brominated phenol novolac type epoxy resin having a biphenyl skeleton as the main component or a curing agent containing a brominated phenol novolac type curing resin. It provides a substrate for printed circuit board which has an extremely high flame retarding property and a superior heat resistance and humidity resistance, as well as a high insulating reliability and a superior high frequency characteristic.

Substrate for printed circuit board

By polishing a surface of a magnetic layer of magnetic recording medium in a direction which coincides with a track angle defined during the recording and reproducing thereof, drop out is decreased and electromagnetic characteristics are improved.

Method for producing magnetic recording medium

In a magnetic recording medium such as VTR tape, a magnetic layer coated on a non-magnetic substrate comprises a binder of polyurethane resin of a reaction products among etheralcohol, polyesterpolyol, diisocyanate compound and silicon compound represented by the following general formula: ##STR1## (R: alkyl group, n: 1 or larger integer) and ferromagnetic powder dispersed in said binder; and the recording medium has very low friction coefficient, high C/N value and high durability without increase of amount of conventional lubricant or anti-abrasion agent in the magnetic layer.

Magnetic recording medium

An electrophotographic photoreceptor for producing an electrostatic latent image on the top layer thereof which comprises from the bottom up:

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Yawata, Japan

Masanaru Hasegawa