Initiatorless Electric Detonator

Abstract

The present invention relates to an electric detonator containing no primary charge or igniting charge, having a simple structure, and capable of directly igniting a base charge of secondary explosive. A detonator of the present invention includes a cylindrical tube closed at one end, a base charge contained in the tube near the closed end thereof, and an ignition device inserted from an open end of the tube and accommodated near the open end. The ignition device is a semiconductor bridge device including a laminate layer and electrode pads. The laminate layer includes layers of a reactive metal and a reactive insulator. The base charge is, for example, pentaerythritol tetranitrate.

1 . A detonator comprising a cylindrical tube closed at one end, a base charge contained in the tube near the closed end thereof, and an ignition device inserted from an open end of the tube and accommodated near the open end, wherein
 the ignition device is a semiconductor bridge device including a laminate layer and electrode pads, the laminate layer constituting two lands on a substrate and a bridge portion electrically connecting the two lands, the laminate layer comprising alternately stacked layers of a reactive metal and a reactive insulator, the electrode pads being electrically connected to at least one reactive metal layer of the laminate layer on the two lands thereof, the electrode pads allowing an applied current of a predetermined intensity to flow through the bridge portion, thereby generating plasma; and   the base charge comprises pentaerythritol tetranitrate or pentaerythritol tetranitrate and at least one substance selected from the group consisting of metals, metal oxides, metal peroxides, metal nitrates, metal chlorates, and metal perchlorates.   
   
   
       2 . A detonator comprising a cylindrical tube closed at one end, a base charge contained in the tube near the closed end thereof, and an ignition device inserted from an open end of the tube and accommodated near the open end, wherein
 the ignition device is a semiconductor bridge device including a laminate layer and electrode pads, the laminate layer constituting two lands on a substrate and a bridge portion electrically connecting the two lands, the laminate layer comprising alternately stacked layers of a reactive metal and a metal oxide, the electrode pads being electrically connected to at least one reactive metal layer of the laminate layer on the two lands thereof, the electrode pads allowing an applied current of a predetermined intensity to flow through the bridge portion, thereby generating plasma; and   the base charge comprises pentaerythritol tetranitrate or pentaerythritol tetranitrate and at least one substance selected from the group consisting of metals, metal oxides, metal peroxides, metal nitrates, metal chlorates, and metal perchlorates.   
   
   
       3 . The detonator according to  claim 1  or  2 , wherein the reactive metal layer electrically connected to the electrode pads is the topmost layer of the laminate layer. 
   
   
       4 . The detonator according to  claim 1  or  2 , wherein the reactive metal is titanium, tungsten, zirconium, or nickel. 
   
   
       5 . The detonator according to  claim 1 , wherein the reactive insulator is boron. 
   
   
       6 . The detonator according to  claim 2 , wherein the metal oxide is SiO 2  or TiO 2 . 
   
   
       7 . The detonator according to  claim 1  or  2 , wherein the base charge comprises pentaerythritol tetranitrate and a metal. 
   
   
       8 . The detonator according to  claim 7 , wherein the metal is nickel, tungsten, titanium, or aluminum.