Abstract:
The ignition device according to the present disclosure implements in a reliable manner a one-time transient switching process for high voltages (&gt;1.5 kV) and high currents (&gt;3 kA) in combination with a minimal space requirement, maximum environmental durability and at the same time low cost expenditure by integrating the essential components on a flexible printed circuit system.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to German patent application, DE 10 2015 009 576.5, filed Jul. 23, 2015, the entire disclosure of which is incorporated by reference herein. 
       TECHNICAL FIELD 
       [0002]    The present disclosure concerns an ignition device for an explosive charge of an active body comprising at least one ignition circuit and a device for transmitting the completed initiation. 
       BACKGROUND 
       [0003]    Such ignition devices, which generally comprise at least one ignition circuit with an energy storage device (capacitor) and a switch, with which the stored energy is used to trigger a component by closing the switch. 
         [0004]    An EFI ignition module that operates according to the principle has become known from DE 10 2011 108 000 A1, wherein ultimately a synthetic pellet is ignited. An ignition bridge that is provided in the ignition module is suddenly evaporated by feeding in electrical energy from a capacitor and thereby a small part is blasted out of the film that is disposed above the ignition bridge using the barrel that is disposed above the film. The part has sufficient shock wave energy for triggering the synthetic pellet. 
       SUMMARY 
       [0005]    Since no further instructions are to be obtained from the document regarding ways to further reduce the size of an ignition module, an object arises of finding a design that enables a further reduction of the structural volume without restricting the required discharge currents (&gt;1000 A) and voltages (&gt;1 kV). 
         [0006]    This object is achieved according to the present disclosure by implementing the ignition device as a compact component that comprises two thin, strip-shaped metal layers that are separated from each other by an electrically insulating plastic layer. Further embodiments of the present disclosure can be found in the secondary claims. 
         [0007]    Particular advantages of the ignition device include that first a considerable reduction of the required space is achieved compared to the known embodiment. Connected therewith, no small reduction of the costs of manufacture is also achieved. Furthermore, the scatter of the characteristic values is reduced and the long-term stability is considerably increased. Regarding the required supply voltage, it is positive to note that in no case does the supply voltage have to be increased compared to the prior art, as no particular spark gaps have to be used. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Exemplary embodiments of the present disclosure are represented schematically in a simplified form in the figures of the drawing and are described in detail below. In the figures: 
           [0009]      FIG. 1   a:  shows a first embodiment for the initiation of a low impedance load in the rest phase; 
           [0010]      FIG. 1   b:  shows the ignition device of  FIG. 1 a    in the first activation phase; 
           [0011]      FIG. 1   c:  shows the ignition device of  FIG. 1 a    in the ignition phase; 
           [0012]      FIG. 2   a:  shows a further embodiment with integrated EFI in the rest phase; 
           [0013]      FIG. 2   b:  shows the ignition device of  FIG. 2 a    in the first activation phase; 
           [0014]      FIG. 2   c:  shows the ignition device of  FIG. 2 a    in the second activation phase; and 
           [0015]      FIG. 2   d:  shows the ignition device of  FIG. 2 a    in the ignition phase. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    In  FIGS. 1   a,    1   b  and  1   c  a first exemplary embodiment is shown. Using  FIG. 1   a,  in which the rest state of the ignition device is shown, the components of the ignition device first are described. The upper half of  FIG. 1  shows the individual, mutually separated parts in a top view and also the external circuitry thereof in a simplified form. The lower half shows a section along the imaginary center line of the parts from the upper half and illustrates that together the parts form a compact component. 
         [0017]    In detail, the ignition device comprises a first thin metal layer M 1  and a further thin metal layer M 2 , between which a thin electrically insulating plastic layer K is disposed. Moreover, the first metal layer comprises another ignition bridge ZB of a known design. Exactly above the ignition bridge, a barrel B is disposed in the further metal layer M 2 . Below the same there is a sharp-edged through opening. Both metal strips are of a strip-shaped form and thus form longitudinal sides and narrow sides. The ignition bridge ZB of the exemplary embodiment thus divides the longitudinal sides approximately in the center thereof. 
         [0018]    In the exemplary embodiment, the connections for the elements of the so-called trigger circuit, which essentially comprises or consists of a series circuit of the switch S and of a capacitor C 1 , are provided on the narrow sides of the first metal layer M 1 . In the rest phase the switch S is open, so that no current can flow in the trigger circuit. The capacitor is configured for operating voltages (&lt;˜1000 V) that are switchable by semiconductors and comprises a sufficient capacitance to evaporate the ignition bridge. 
         [0019]    Moreover, a series circuit of the load V and of the ignition capacitor C 2  is provided from the first metal strips M 1  to the further metal strips M 2 . The load V is the element to be ignited, for example the ignition circuit of an explosive charge (EFI). The ignition capacitor C 2  has a high operating voltage (&gt;1000 V) and a corresponding high capacitance. 
         [0020]      FIG. 1 b    shows the point in time at which the switch S is closed and the capacitor C 1  can discharge. As a result, a suitable current flows and the ignition bridge ZB evaporates. 
         [0021]    The situation shown in  FIG. 1 c    then follows. Owing to the evaporation of the ignition bridge ZB, there is an enormous pressure that acts directly on the contacting plastic film K. The part T of the plastic film K is pressed upwards as a result and is punched out of the barrel B into the further metal layer M 2  and accelerated through the barrel B, as can be clearly seen in  FIG. 1   c.    
         [0022]    Owing to the narrow thickness of the plastic film K, there is at the same time an ignition spark ZF through the opening that has been left in the part T of the plastic film. As a result, the ignition circuit is closed by the high voltage switch via the two metal layers M 1  and M 2  and the capacitor C 2  and the load V, and the load V is initiated. 
         [0023]    Another embodiment of the present disclosure, but which operates according to the same principle, is represented in individual phases in  FIGS. 2   a,    2   b,    2   c  and  2   d.  The figures are again divided into a representation of the individual components in a top view disposed in the upper half and a section along the imaginary center line of the components shown above in the lower half. The external circuitry with capacitors is also shown in the upper half. 
         [0024]    The embodiment of the ignition device also comprises a first thin metal layer M 12 , which in turn comprises an ignition bridge ZB, and a further thin metal layer M 22 , which is separated from the first metal layer by a thin insulating plastic film K. A series circuit (trigger circuit) of the switch S and the capacitor C 1  is connected to the two ends of the ignition bridge ZB. 
         [0025]    The situation immediately following the closure of the switch S is illustrated in  FIG. 2   b.  The charging of the capacitor C 1  causes the evaporation of the ignition bridge ZB. Owing to the pressure generated, in turn a part T of the plastic film K is punched out and accelerated through the barrel B. 
         [0026]    As shown in  FIG. 2   c,  the ignition spark ZF can be formed owing to the opening punched out of the plastic film. As a result, the ignition circuit from the first metal film M 12  via the capacitor C 2  to the further metal film M 22  is closed and the EFI (Exploding Foil Initiator) that is disposed in the first metal film M 12  outside the trigger circuit is ignited. 
         [0027]    The EFI also punches a plastic flyer KF out of the plastic film K. For this purpose, the further metal film M 22  also comprises a component with the function B 2  of a barrel that is disposed directly above the EFI. The plastic flyer KF is dimensioned regarding the dynamics thereof so that it can initiate the booster (secondary explosive, for example HNS) with the pulse thereof. 
         [0028]    The embodiment described is represented by way of example and in a simplified form. In an implementation, it is provided to develop a design in which, in addition to the EFI and the booster in the form of an explosive pellet, the switch and the capacitor of the ignition circuit are also integral components of the ignition device according to the present disclosure. 
         [0029]    The subject matter disclosed herein can be implemented in or with software in combination with hardware and/or firmware. For example, the subject matter described herein can be implemented in software executed by a processor or processing unit. In one exemplary implementation, the subject matter described herein can be implemented using a computer readable medium having stored thereon computer executable instructions that when executed by a processor of a computer control the computer to perform steps. Exemplary computer readable mediums suitable for implementing the subject matter described herein include non-transitory devices, such as disk memory devices, chip memory devices, programmable logic devices, and application specific integrated circuits. In addition, a computer readable medium that implements the subject matter described herein can be located on a single device or computing platform or can be distributed across multiple devices or computing platforms. 
         [0030]    While at least one exemplary embodiment of the invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority. 
       REFERENCE CHARACTER LIST 
       [0031]    M 1 , M 12  first metal layer 
         [0032]    M 2 , M 22  further metal layer 
         [0033]    K plastic layer 
         [0034]    B, B 2  barrel 
         [0035]    T part (of the plastic layer) 
         [0036]    KF plastic flyer 
         [0037]    S switch 
         [0038]    C 1  capacitor (&lt;300 V) 
         [0039]    C 2  capacitor (&gt;1500 V) 
         [0040]    V load 
         [0041]    ZB ignition bridge 
         [0042]    ZF ignition spark 
         [0043]    EFI Exploding Foil Initiator 
         [0044]    FL flyer 
         [0045]    HNS booster (explosive pellet; secondary explosive)