Toppan Printing Co., Ltd.

Shoji Yokokoji

Moriyoshi Kurosawa

Takashi Sajiki

Kiketsu Hasegawa

Yoshiyasu Noguchi

Yasuharu Nagatomo

Shozo Saito

An electromagnetic absorbing element is comprised of an elongated rectangular body of dielectric material having a bottom portion attachable to an inner wall of an electromagnetically dark room, and peripheral elongated faces extending vertically from the bottom portion such that a set of the absorbing elements can be arranged in rows-and-columns on the wall. An electroconductive ink film is formed on the peripheral faces of body and has a gradually changing surface resistivity decreasing exponentially lengthwise of the peripheral face toward the bottom portion. The incident electromagnetic wave normal to the wall provided with the rows-and-columns of absorbing elements is absorbed by a lattice of the electroconductive films during the travel along the electroconductive films.

Electromagnetic wave absorbing element

The printed circuit board for mounting electronic parts thereon is obtained by transferring flux from a supporting film to the surface of a printed circuit board, and soldering the electronic parts thereto after the supporting film is removed. The supporting film is first coated with the flux, and the flux is transferred to the printed circuit board through the application of heat and pressure. Hot air can be blown from an oblique direction on the flux-coated surface of the printed circuit board after the flux is transferred thereto and before the electronic parts are soldered thereto. This method can provide a uniform flux coat on the printed circuit board and can eliminate various drawbacks which are encountered in conventional approaches in which the surface of the printed circuit board is coated directly with flux in liquid form.

Process for manufacturing a printed circuit board

Growing community of inventors

Tokyo, Japan

Shoji Yokokoji