Kabushiki Kaisha Sankosha

Agency of Industrial Science and Technology Ministry of International

Sankosha Corporation

Mitaka Denshi Kagaku Laboratory Inc.

Yuji Muramatsu

Daizo Shigemori

Yutaka Hayashi

Masaaki Sato

Hirofumi Yoshihara

Teiji Hasegawa

A surge absorption device includes fundamentally a first semiconductor region, a second semiconductor region forming a pn junction between itself and the first region, a third region determining the effective thickness of the second region, and a fourth region provided in contact with the first region and forming an injection junction for causing first minority carriers of a kind the same as that of minority carriers in the first region to be injected into the first region. When a depletion layer formed by application of reverse bias across the pn junction reaches the third region, a punch-through region is formed in the second region. In this state, when minority carriers are injected from the fourth region into the first region, the minority carriers are absorbed by the second region to constitute the device current.

Surge absorption device

A pair of main electrodes are hermetically mounted, by fusion of a low melting point metal, onto both end openings of an insulative cylindrical member, respectively. Main electric discharge surfaces of the electrodes oppose each other in said cylindrical member with a gap interposed therebetween. A recessed portion is provided in the main electric discharge surface of one of the pair of main electrodes. A pair of trigger electrodes are conductively connected to the pair of main electrodes, and oppose each other in the recessed portion to thereby form a trigger electric discharge gap therebetween. The pair of main electrodes are formed of electrically conductive material having a thermal coefficient of expansion greater than that of the insulative cylindrical member. The dimension of the trigger electric discharge gap is given as the dimension of the gap between the trigger electrodes which is produced due to the difference in the thermal coefficient of expansion between the pair of main electrodes and an insulative cylindrical member when the trigger electrodes are caused to contact each other by zeroing the gap therebetween and, in this state, the pair of main electrodes are hermetically mounted, by fusion of the low melting point metal, onto both end openings, respectively, of the insulative cylindrical member and, thereafter, the resultant unit is cooled down to room temperature.

Anti-overvoltage protector

An overvoltage protecting element of the invention has a pair of main electrodes, the discharging surfaces of which oppose each other with a gap therebetween in a cylindrical body of an insulator, and a conductive member which is formed on the inner wall surface of the cylindrical body to oppose the main electrodes with a gap therebetween, and a plurality of extended parts of which extending in the circumferential direction of the cylindrical body being connected in the axial direction of the cylindrical body. The main electrodes and the conductive member are electrically connected to each other by capacitive coupling.

Overvoltage protecting element

Growing community of inventors

Machida, Japan

Yuji Muramatsu