SE468297B - Detonator-firing element - Google Patents

Abstract

Detonator-firing element which comprises a miniaturized energy-discharge arrangement 12; 102; 104; 225 positioned on a substrate 10 which forms part of an integrated electronic circuit. An explosive charge or pyrotechnic mixture 60; 222 is exposed to the effects of the energy discharge which is performed by the arrangement. The arrangement can be resistance-based, be formed by a semi- conductor or be a field effect arrangement. The integrated circuit comprises timing, test, control, communication and interlocking circuits so as to make possible individual or computer-controlled detonation systems. Protection 30; 14 against overvoltages and induced currents are provided. By using integrated circuits, power consumption is kept to a minimum and a detonator which comprises the firing element can be supplied with power for a considerable period of time by an energy storage arrangement, such as a capacitor 84.

Description

468 297 of energy, characterized in that it comprises a passivation layer between at least a part of the substrate and at least a part of the explosive.

The invention further comprises a detonator comprising a container and wherein a detonator firing element according to the invention is mounted in the container together with an explosive material, which is arranged to be initiated by said explosive substance.

Finally, the invention comprises a series detonation system, which comprises interconnected detonators according to the invention and means for controlling the firing of individual detonators.

-Compared with other ways of tackling the problem, an extremely low quantity of energy is diverted with the diverting device.

The substrate is preferably suitable for the manufacture of a customized, large-scale integrated circuit.

The energy dissipation device may be a resistive element or may be formed by a semiconductor device or may be a field effect device.

In the first case, the energy dissipation device may be formed by a resistance layer, which is deposited on the substrate. 3 468 297 A current which is caused to pass through the resistance layer causes heating thereof. As an example, the resistance layer may be formed of at least one of the following. which are hereinafter referred to as "the preferred materials": chromium nickel, gold. tungsten, aluminum, zircon, polysilicon, titanium / tungsten mixture and metal silicon compounds.

A resistance element can also be designed e.g. by means of a diffusion or implantation technique, and in the former case e.g. a layer of P-type silicon be diffused into a predominantly N-type silicon substrate to provide the resistive element. The P- and N-type silicon layers can be exchanged for each other. In the latter case, ion implantation techniques can be used to form the resistive element.

The resistance element can be designed so that it emits heat when an electric current is caused to pass therethrough. In a variant of this way of approaching the problem, the resistance element is designed so as to form a fusible connection, which is melted when a current of predetermined amplitude passes through it. The digestion of the compound then releases a predetermined quantity of energy. The release of energy is used to initiate a primary explosive charge. A number of compounds can be used on the same substrate to increase the probability of initiation.

The compound or compounds preferably have low impedance. This is very important for energy density reasons. and in one respect it can be said that each connection can be more accurately described as a conductor than as a resistor. Thus, in a preferred embodiment, a fusible compound formed directly in the normal bonding metal on the substrate, i.e. on the chip without the need to apply any resistor or metal or the like, possibly in a separate process step. The chip can thus be treated in a normal way and has the ability to create an extremely high energy density. A connection of the type described needs a special, very low impedance switch. which would normally need a large silicon surface. By utilizing the semiconductor breakthrough phenomenon and by operating the switch at a current density level which would normally be catastrophic, the high current pulse can. needed to melt the exposed site with low impedance, i.e. the connection is switched on the chip using a relatively small switch construction. This is possible because the switch only needs to work once.

When using deposition techniques to form the resistive element, the element can be deposited in a thin layer on the substrate with a thickness of the layer of e.g. between 10 and 1000 nanometers. A mask can be used to form a desired pattern on the resistance element and contact surfaces and excess material can be etched away or removed in another suitable manner. The resistance element. which is designed in this way, has a very low thermal mass and can be heated by the discharge of a minimal quantity of electrical energy.

As pointed out, the energy dissipation device may alternatively comprise a semiconductor. Suitable elements are transistors, field effect transistors or similar devices. four-layer devices. zener diodes, LEDs, or any other suitable element. which emits heat or light energy after activation. which preferably takes place by allowing an electric current to pass through the element. The energy can be diverted within a narrow region between active N and P regions.

This makes it possible to accurately concentrate the energy released.

According to a third variant of the invention, the energy dissipation device can be a field effect element. The field effect element may be formed by first and second spaced apart electrodes on the substrate, and switching means for applying an electric potential across the electrodes. In this way, a high-intensity electric field is created between the electrodes.

The electrodes may be metallic or formed of any of the preferred materials.

The electrodes can be substantially two-dimensional in that motto f! 468 297 that they are formed of conductor bodies in planar layers on the substrate; alternatively, they may be three-dimensional insofar as they extend to three orthogonal dimensions.

The electrodes may be of any suitable shape.

The electrodes can e.g. consist of separate plates, which are parallel to each other. The electrodes can otherwise be curved, triangular or shaped in any way. In one form of the invention, the electrodes are shaped as a cam or double cam structure.

In one form of the invention, the electrodes comprise first and second conductive bodies, and the first body is formed with an open central portion. which is absorbed by the other body. The bodies form an annular gap between them over which the potential difference is generated.

The electrodes may be formed in any suitable manner and are preferably formed by depositing one of the preferred materials on a dielectric oxide layer on the substrate. The material can be etched to the desired shape.

The switching means may comprise first and second switching devices with the first device connected between the first and second electrodes and the second device connected to the second electrode and to a pole of an electrical voltage source. and the first electrode connected to the second pole of the electrical voltage source. In idle mode, i.e. when an explosion is not to be initiated, the first switching device is switched on and the second switching device is switched off. The detonator firing element is then put into operation by turning the first switching device to the off position and the second switching device to the on position. In this way, the electrical potential is applied across the electrodes.

An explosive charge can be placed near or in direct contact with the energy dissipation device, which after being activated initiates the explosive by dissipating energy. As pointed out, in most cases of the invention the dissipation of energy causes the release of heat and this heat is used to initiate the explosive. however, it is possible to cause the energy to be dissipated in the form of light, the light initiating the explosive.

In the third variant of the invention, i.e. the one based on the use of a field effect device. the explosive is activated by an electrostatic discharge or by a high electric field.

Suitable explosives are primary explosives such as silver azide, lead or barium hardened, mercury fulminate and any suitable secondary explosive such as RDX and HMX, a mixture of any of the foregoing or any other suitable. fixed. liquid or gaseous material with desired characteristics. The explosive material itself may be designed to be conductive by the addition of small amounts of a conductive material, such as graphite or an organic semiconductor. In this way, the explosive material can be heated directly depending on the current flow induced therein. In the case of a field effect device, the explosive may comprise a component such as an organic semiconductor which carries an oxidizing agent which reacts chemically in the presence of an electric field with an exothermic reaction. More generally, the explosive material in the field effect device may comprise a field sensitizing activator.

The substrate may form part of a semiconductor device. which includes integrated circuits for controlling the activation of the detonator firing element. The detonator firing element may be located on the surface of an oxide layer. covering the electronic device, with suitable openings provided to enable electrical contact with the device. Alternatively, it may be located below the oxide layer, with or without an opening or openings through the oxide layer. It can be noted that a cover over the detonator firing element reduces its sensitivity. ”68 297 The explosive is located in the vicinity of the energy dissipation device. Preferably, the explosive is adhered to at least one surface of the substrate so that it is in intimate physical contact with the substrate. Liquid or gaseous explosives may in particular be provided, e.g. together with the energy dissipation device in a sealed container. In this way, efficient energy transfer takes place between the energy dissipation device and the explosive.

The quality of the physical contact between the explosive and the substrate can be improved by using an adhesion promoter. This improves the bond between the explosive and the surface of the substrate. The explosive can be deposited in solution or as a liquid suspension. The adhesion promoter may consist of a wetting agent. A binder such as PVC or nitro lacquer can be added to the solution or suspension. At the same time, the unit gains mechanical strength when using a solid explosive.

The explosive unit and detonator firing element may be coated with a suitable inert protective sealant, such as a silicone rubber, which adheres to the substrate and, as it cures, contracts the explosive and the substrate.

In one form of the invention, a window is provided in the substrate with the energy dissipation device disposed therein.

The explosive is then placed in the window in contact with the energy dissipation device. It is pointed out, however, that the window is not essential to the invention and that in some cases it is sufficient if the explosive is placed in close contact with the energy dissipation device.

The explosive may alternatively be liquid or gaseous and may be sealed in a container together with the energy dissipation device. This prevents deposition problems for the explosive.

The control circuit included in the semiconductor device may comprise pre-defined logical building blocks to offer customized explosion control systems at low development costs. Such building blocks can e.g. include oscillators. counters and timers. phase locking circuits for precise timing. communication circuits, interlock circuits, self-testing circuits and electromagnetic interference suppression circuits.

The combination of a miniaturized detonator firing element of the type described and an integrated electronic circuit results in a complex signal processing being achieved at low cost and with a high reliability factor. Overvoltage protection devices may be included to protect the energy dissipation device against unwanted initiation. Traditionally, detonator firing elements have not been made small enough as a decrease in size leads to an increase in sensitivity to leakage voltages or currents. However, by using a starting point with an integrated circuit and by arranging an overvoltage protection, a high degree of immunity to electromagnetic interference is achieved. The protective arrangement may also comprise switching means. which are connected to the energy dissipation device to provide protection against induced electric currents.

A detonator firing element of the type described can be delivered mounted in a housing, with explosive material in the housing arranged to be initiated by the initiating explosive, as mentioned above, to thereby form a detonator.

Means are provided for applying electrical energy to the energy dissipation device and the circuits. This means may comprise a capacitor, which is controlled by a timing circuit or any other electrical storage device.

Energy can be obtained from incoming power supply lines and used to charge energy storage means, which may comprise the aforementioned capacitor. This provides backup power if the wires leading to the detonators are damaged, e.g. during -blasting- operations. ml Q 468 297 If you use a high capacitance capacitor, there is an additional advantage that the power supply is disconnected and crosstalk and interference are reduced.

The energy storage capacitor and the ultra-low power consumption of the energy dissipation device, which forms an explosive initiating operating point. combined with the use of CMOS technology to fabricate the integrated circuits, low cost and efficient solution to the problem of ensuring detonation during stone throwing during blasting operations.

The high impedances associated with low power circuits and local energy storage facilitate the use of low cost connections, as the energy storage capacitor can be charged over a relatively long period of several seconds.

The invention also comprises a series detonation system comprising a number of detonators of the type described which are connected in series and means for controlling the firing of the individual detonators.

The control means may be adapted to program a selected delay interval in a time circuit. belonging to each detonator. surge protectors may be provided between selected pairs of detonators. This further increases the immunity of the system to induced voltages or currents.

Description of the drawings The invention will be described in more detail below with reference to examples shown in the accompanying drawings.

Figure 1 is a plan view of an integrated electronic detonator comprising a resistance-based detonator firing element in accordance with one form of the invention. 468 297/0 Figure 2 is a cross-section through the circuit of Figure 1, Figure 3 illustrates an embodiment of a circuit which may be arranged in each detonator.

Figure 4 is a side view, partly in cross section, illustrating the physical composition of a detonator firing element.

Figure 5 shows a detonator constructed in accordance with the invention, Figure S illustrates a protection device used in a series detonation system in accordance with the invention, Figure 7 illustrates a series detonation system in accordance with the invention, Figure 8 is a plan view of a field effect based detonator firing element included in an integrated circuit in accordance with the invention, Figure 9 shows from the side and in cross section the physical structure of a detonator firing element.

Figure 10 is a cross-sectional side view of a detonator firing element in accordance with another form of the invention. Figure 11 is a perspective view of the detonator firing element of Figure 10 before a primary explosive charge has been connected thereto.

Figures 12A, 128 and 12C are partial cross-sectional side views of three related embodiments of the detonator firing element according to the invention, Figures 13 to 16 illustrate other embodiments of the invention, and Figure 1? is a cross-sectional side view of a detonator I, 468 297 comprising a detonator firing element in accordance with a variant of the invention.

Description of Preferred Embodiments Figure 1 illustrates from above an integrated electronic detonator 10, which includes a detonator firing element 12, a transistor 14, connecting pads 16. surge protection circuit 18 and timing and communication circuits 20.

The detonator firing element 12 is in fact a miniature fuse with extremely low thermal mass and it is formed by depositing a thin layer of resistive material, or some other of the preferred materials on top of a passive layer of an integrated circuit. The thickness of the resistive layer is in the range of 10 to 1,000 nanometers. A mask is used in a conventional manner to define the pattern on the detonator firing element and on contact surfaces to be maintained and excess material is then etched away.

The integrated circuit on which the detonator firing element is manufactured is shown in cross section in Fig. 2. In this example, the circuit is of the CMOS type and its construction is substantially conventional and therefore it is not further discussed. With reference to Figure 2, the following components can be identified: A silicon layer, of N-type: reference 20 Cultured field oxide: reference 22, P-diffusion regions: reference 24.

Deposited oxide: reference 28.

Polysilicon coupling: reference 28.

Thin coupling oxide: reference 30, Aluminum joint layer: reference 32.

Oxidation or scratch protection layer: reference 34, Detonator firing element: reference 12.

The transistor 14 shown in Figure 1 is of the field effect type and is defined by the areas 24, the coupling 28 and the coupling oxide 30. 468 297 M The aluminum connecting layer 32 is connectable to the connecting pads 16. see Fig. 1, via contact openings in the oxide layer 34.

Figure 3 illustrates, substantially in block form, the details of the integrated circuit. which includes the detonator firing element. In Figure 3, the detonator firing element 12 is illustrated as a resistor in series with the field effect transistor 14. Two 16 volt zener diodes 36 formed in series across the components 12 and 14 are connected to power supply lines 38 and 40. These diodes are intended to prevent leakage energy from activating the detonator and are located below the deposited oxide layer 26. This layer is thermally insulating.

The circuit of Figure 3 includes an oscillator 42 with a time capacitor 44, which is immersed below the detonator firing element, a communication circuit 44 which includes a phase locked circuit which synchronizes the clock, which is on the chip and which is unstable, to an accurate data clock to ensure exact timing of the circuit, and a timing and interlocking circuit 46. The circuit is clocked by the phase lock circuit reference clock.

The circuit further comprises a self-test module 48. which controls all circuit functions during power generation.

Diodes 50 and resistors 52 in the wires D (clock data), DI (data input). R (answer). and DO (output). offers static protection for the CMOS circuit.

The field effect transistor 14 is arranged to control the discharge of electrical energy from a storage capacitor 54 through the detonator firing element 12. The storage capacitor is relatively large and does not form part of the integrated circuit but is rather a separate component.

Figure 4 shows the component 10 mounted in a housing 56, which is molded from a suitable plastic material and comprises a cavity 58 in which the component 10 is inserted. The remainder of the cavity is occupied by explosive 60. The cavity is sealed by means of a molded lid 62 of plastic material. Contact pins 64 'N / 3 468 297 extend through the housing 56 and are connected to the component by means of wires 66. The component 10 is positioned so that the detonator firing element 12 faces the cavity 58 and is in contact with the explosive 60.

The housing 56 includes a second cavity 67, which is occupied by the storage capacitor 54, illustrated in Figure 3. The housing is formed with a first groove 58 in the center and a second groove 70, which extends around the cavity 67.

Figure 5 shows the housing 56 connected to a detonator sleeve 72 to form a complete detonator 74. The detonator sleeve is filled with a suitable explosive and is attached to the housing 56 by being crimped into a position 76 in the groove 68. The housing 56 is oriented so that the cavity 58 with its explosives extending into the detonator sleeve.

A wiring harness 78 which provides electrical contact with the pins 84 is connected to the upper end of the housing 56 and is attached to the housing to communicate with the upper groove 70.

Figure 5 illustrates a protection device 80 which was used in conjunction with a number of detonators 74 shown in Figure 5.

The protection device comprises a fast voltage breakthrough diode 82, which is shunted by a capacitor 84, which provides a low impedance path for high frequency interference.

The device 80 has connections identical to those shown in Figure 3 for the component 10. Thus, it has two power line connections 86, 88, which correspond to the connections 38 and 40 in the device 10 and D-, R-, D1- and Dü-connections, which correspond in the same way to marked connections in the diagram according to Figure 3. It should be noted that the connections D1 and 00 are directly connected and therefore offer a path which is transparent to signals emitted along the data line. The D and R connections are not used in any way.

Figure 7 illustrates a series blasting system. comprising a number of detonators 74 with protection devices 80 connected in selected 468 297/1 / positions between adjacent pairs of detonators. The order of the detonators is determined by a device 90. The DO and DI connections in adjacent devices are interconnected to provide a daisy-chain chain connection along the system.

The detonators are physically mounted in desired positions in accordance with conventional mining technology. In electrically noise-prone environments, the number of protection devices 80 is larger to improve the system's interference immunity.

The bursting system includes an electrical interface 92, which supplies power to the detonators and which translates signal protocols between a conventional communication link 94 from a control computer 96 and the detonator signals.

It is desirable to test a series explosion installation at low voltage using field test units before the explosion sequence is actually initiated. The test should preferably take place under energy supply conditions where the supply voltage is below 3 volts. which ensures that, in the event of a malfunction, none of the detonator firing elements can be heated sufficiently to cause detonation. The test sequence is designed to indicate faulty units by entering a number before their connection to the blasting system.

The computer is used to generate delays for controlling the desired burst sequences. The manner in which the delay signals are generated is not essential to understanding the present invention and is therefore not addressed in the specification.

All detonators 74 in the system, shown in Figure 7, are identical and no programming of user addresses is desirable. However, to allow the individual detonators to be addressed despite this, a clear signal is included in the communication scheme. This allows each device to activate its nearest one as soon as it has completed its own communication. Thereby, the computer confirms a ready signal, the first device is addressed and responds and then it confirms its ready signal to the next device.

The computer communicates with all the devices in the line in turn until the penultimate device confirms its ready signal to the closed unit 90. This unit then signals to the computer that the end of the chain has been reached, whereupon the computer sends out a signal which resets all ready signal lines, so that they are ready in the system for the next communication cycle. In this way, each device can be assigned a number by the computer for troubleshooting and general communication.

To prevent false firing, several communication cycles can be used with an interlocking mechanism. The sequence can e.g. be as follows: the system is first energized and the computer addresses each device and obtains the results of the self-test process, which is performed by means of its own circuit in each detonator and by the number of detonators. The computer then prints a delay time for each detonator and each detonator returns the delay to the computer for verification.

The detonators are then reinforced using a statistically unique signal. for example a signal that has a low correlation with random disturbance in the current environment. Then a "start sequence" is initialized. which again occurs with the help of a statistically unique signal and this causes detonation.

The proposed safety interlock sequence allows current to pass through each detonator's detonator firing element only on the self-test. performed on the particular detonator is satisfactory and the devices have a delay which is properly programmed. a valid reinforcement sequence has been received. a valid start signal has been received and the delay period has expired.

In a tested example of the invention, a 4.7 microfarad capacitor discharged 14.7 V into a detonator firing element. which had a comminuted compound with the dimensions 80 μm x 9 μm. The compound was covered with lead typhoon The reaction time measured from the application of current to the aiming of a lightning bolt from the exploding lead typhanate was 30,468,297 M milliseconds. The energy supplied was therefore slightly less than 20.9 uJoule.

The energy for heating the detonator firing element is stored in the capacitor 54. This capacitor has a capacitance of 10 HF and is conducted to 11 volts. which provides sufficient energy for driving the circuit and for heating the detonator firing element. Thus, each detonator is powered by its own power and as soon as the delay period has elapsed, it will explode in a timely manner even if the lines connecting it to the main power supply have been damaged.

Since no strong firing current passes through the system, low-quality connections can be used to connect the devices in the bursting system.

The time during which each device can operate, as soon as it has been disconnected from the power supply, is limited by the size of the capacitor. A considerable number of detonators can be connected in a series detonation system with long intervals between the detonations. which gives long explosion times. 'When the detonator explodes. as the year furthest from the power supply first, the total energy storage requirement for each device will be significantly reduced. Because force is fed in one direction. which is the opposite of the direction in which the explosion develops, thrown stones can isolate the force locally.

It is therefore preferable that the detonators be fired in reverse order to achieve the benefit of reduced energy storage requirements.

The invention offers detonators which make it possible to use fully integrated. cheap and reliable jumping systems. Sequence delays in the system are precisely defined and complex burst patterns are relatively easy to program.

The starting point for the invention is to integrate the detonator firing element in an electronic chip. The chip also includes suitable circuits for performing self-tests of time and protection functions. 1 Ȇ 468 297 There are two surge protection steps, namely those provided by the protection device 80 and by the protection system on the chip. The protection voltage level on the chip is 12 V while the voltage level on each of the devices 80 is 11 V.

This ensures sufficient isolation of the detonator firing element from unwanted signals in the series burst system.

Figures 8 and 9 show a detonator firing element. which is based on a field effect design.

Figure 8 illustrates in plan a integrated circuit 90, which includes a detonator firing element generally designated 92, control transistors 94 and 96, respectively, overvoltage protection circuits 98 and a timing and communication circuit 100.

The function of the circuits 98 and 100 and the manner in which the detonator firing element is used, including its confinement in a series detonation system, can generally be accomplished in the same manner as in the previous description.

The detonator firing member 92 in this example includes a first. inner electrode 102, which is circular to its worm and a second. outer electrode 104, which is located concentrically around the inner electrode, the two electrodes defining an annular gap 106 between them. These shapes are to be considered as examples only.

Transistors 94 and 96 are field effect transistors.

The transistor 94 has its collector connected to a positive pole 108 of an electric supply nut and its current source is connected to the electrode 102. Its gate is controlled by the circuit 100.

Transistor 96, on the other hand, has its electrode connected to a negative pole 110 in the electrical supply network with its collector connected to the inner electrode 102. The gate of the device 96 is connected to the circuit 100. The outer electrode 104 is also connected to the pole 110.

The two electrodes 102 and 104 are formed by depositing one of the preferred materials on top of an oxide layer on the integrated circuit 468 297 hours. The deposited metal is then etched to the desired shape.

Figure 9 illustrates the mounting of the circuit 90 in a cavity 112 in a housing 114. Pin 116 extends through a base in the cavity into a lower cavity 118. The pins are connected to the circuit 90. Analogously to the method already described, the pins are used for the power supply to the circuit, for data and clock information, response information, output data and input data.

The cavity 118 comprises a storage capacitor, not shown, which is connected to those of the pins 115 which define the poles 108 and 110 for supplying power to the detonator firing element 92.

An insert 120 is mounted in the housing 114. The insert has a conical recess 122 whose base terminates in a cylindrical passage 124. which extends to and over the electrodes 102 and 104.

A primary explosive material such as silver azide, lead azide or lead stiffened is packed in recess 122 and passage 124.

The insert 120 forms a sleeve and ensures that the explosive is enclosed in contact with the electrodes. The insert 120 is preferably of an electrostatically conductive plastic material to reduce the risk of leakage electric fields initiating the primary explosive material. The insert is in physical and electrical contact with the outer portion of the housing 114, which is electrically grounded by a suitable pin 116.

The component shown in Figure 9 is designed to be connected to a detonator sleeve filled with a suitable explosive and which is fixed to the housing 114. The housing 114 is partially inserted into the mouth of the sleeve with the primary explosive and extends into the sleeve so that the pin 116 projects from the sleeve. The sleeve is then crimped into a groove 126 in the outer surface of the housing 114 to secure the components together. Another groove 128 is used to lock a cable network to the housing 114. The network provides electrical connections to the various pins 116. / 7 468 297 A number of devices shown in Figure 9 are included in a serial blasting system in the manner described above in in accordance with the prior art or in accordance with the procedure described above.

The storage capacitor in the cavity 118 is charged by a primary electrical source. Transistors 94 and 96 are controlled by circuit 100. Circuits 98 and 100 are each controlled by data fed to the detonator along the input line. Appropriate firing delays can be programmed into the circuits.

The detonator firing element is controlled as follows. Under normal conditions, i.e. in the unarmed position, the transistor 94 is turned off and the transistor 96 is turned on. The latter device, when turned on, holds the electrodes 102 and 104 at the same potential. Thus, there is no potential difference across the electrodes across the annular gap 106 or otherwise expressed, the electrostatic field across this gap is D.

If the transistor 94 is turned on and the transistor 96 is turned off, a potential difference will be formed across the gap 106, which is equal to the supply voltage to the electrical source, i.e. the voltage to which the storage capacitor in the cavity 118 is charged.

The electric field across the gap 106 initiates the sensitized primary explosive in the recess 122 and the passage 12k, thereby initiating the explosion of the particular detonator.

The strength of the field. generated in this way can be controlled by varying the width of the gap 106 or by changing the applied voltage. To initiate less sensitive explosives, the potential applied across the gap can be increased by using voltage multipliers. Transistor 94 may be fabricated with an internal resistor. which is higher than that of transistor 95. This ensures that device 96 must be turned off and device 94 turned on before the voltage across gap 106 reaches its desired level, i.e. the level at which initialization of the primary explosive material takes place. This safety detail ensures that both transistors must be operated 468 297 Well correctly for an explosion to take place.

The approach to the problem described in connection with Figures 8 and 9 offers the advantage that the application of special metals such as tungsten (W) or chromium-nickel compounds (NiCr) is made superfluous. Transistors 94 and 96 may also be relatively small. since they are not used for switching large currents but are only used to control the application of voltage across the gap 106.

Figures 10 - 17 relate to further embodiments of the invention.

Figures 10 and 11 show a detonator firing element 210 in the form of a silicon microchip. comprising a silicon substrate 212 covered by a thin layer 214 of a suitable oxidizing material such as a silica. A window 216 is formed in the oxide layer 214 to expose an energy dissipation device in the form of an element or connection 218 of suitable material. The joint 218 is deposited on the substrate 212 by conventional deposition techniques and has a web portion 220 which is arranged substantially centrally in the window 216. A primary explosive material 222 is glued to or compressed against the oxide layer 214 and covers the window 216 to be in contact with the connection 218. The initialization charge 222 is not shown for the sake of clarity in Figure 11.

In some applications, the window 216 is not substantial, and the charge 222 is mounted directly on the oxide layer in close proximity to the joint 218 to be initiated by the joint 218 either by melting or by heating to a sufficiently high temperature by electrically current passes therethrough.

The charge 222 may be made of low stiffened lead binder or an adhesion promoter added thereto prior to its application to the substrate 212 in order to increase its adhesion to the oxide layer 214.

The connection 218 activates the charge 222 either by melting or by being able to assume a sufficiently high temperature due to resistance heating to initiate the charge 222 while it is still intact.

Figures 12A, 12B and 12C show three further embodiments of a detonator firing element 225, which comprises a silicon substrate 227 to which is attached an activating member comprising a metal or conductive layer 226 and an exothermic or oxidizing layer 228 in different configurations. .

In Figure 12A, a layer 224 of dielectric material is attached to or cultured on the surface of the silicon substrate 227. A layer 226 of one of the preferred materials is placed on top of the layer 224 of dielectric material. An exothermic or oxidizing layer 228 is then applied on top of the layer 226. The layer 228 may be a polyamide containing an oxidizing mixture, such as potassium chloride or a pyrotechnic medium. which reacts with the layer 226.

In Figure 128, the exothermic or oxidizing layer 228 is applied to the surface of the silicon substrate 212 and the layer 225 is applied on top of the layer 228.

In Figure 12C, the layer 226 is sandwiched between two exothermic or oxidizing layers 228.

The embodiments of Figure 12 rely for their function on the fact that an exothermic reaction is initiated between the layer 226 and the exothermic or oxidizing layer 228 immediately above and / or below the layer 226. The exothermic reaction is caused by the resistance heating of the layer 226 due to the passage of electric current thereby. The primary explosive charge (not shown) reacts to and is initiated by the exothermic reaction.

The oxidizing layer 228 is deposited during the manufacturing process of the detonator firing element 210.

An advantage of these embodiments is that the deposition of the primary explosive does not have to depend on a good contact being achieved uniformly over the active surface of the detonator firing element 200. Consequently, production variations can be tolerated during disposal of the explosive. Application of oxide layers to the detonator firing element 210 can thus be performed to reduce the lifetime variation. The materials used for oxidation may be polyamides or oxides and nitrides applied at low deposition temperatures or in vacuo.

Figure 13 shows a further embodiment of the invention in which the detonator firing element 230 is in the form of a semiconductor with a silicon substrate 231.

An energy dissipation device 232 comprising a resistor member in an electrical circuit is arranged by means of a section of a diffused, an ion-implanted or an epitaxial element. formed in or on the silicon substrate 231. Metal connections 234 attached to the surface of the silicon substrate 231 in electrical contact with the device 232 are connectable to a drive circuit (not shown). An oxide layer 236 is grown on top of the metal joints 234 as well as on the device 232.

The energy dissipation device 232 may be any circuit element such as a resistor. a transistor or a four-layer diode. It should be noted that if the device is a zener diode or some other type of active device, the energy generated can thereby be focused precisely.

The energy dissipation device 232 may be formed of a layer of P-type silicon which diffuses into a substantially N-type silicon substrate 231 to provide the resistance portion of the circuit.

The layers of P-type and N-type silicon can of course be reversed. More energy can be dissipated in a diffusion resistor before it bursts than would be the case with a conventional metal compound. This gives the advantage of a much better predictable initiation. In addition, it is easy to change the resistance doping to improve the electrical adaptation to near optimal level and also the size can be adjusted easily. This type of device is furthermore better suited for capacitor storage systems since all the remaining energy in the capacitor can be diverted into the resistor.

Figure 14 shows a detonator firing element 240. which is a semiconductor device with a silicon substrate 241. A layer of dielectric material (not shown) can be applied to the silicon substrate 241. A structure that generates an electric field in the form of a comb or double cam structure 242 is applied to the silicon substrate 241 or may diffuse into it. This is obviously an alternative arrangement to that shown in Figures 8 and 9. A connecting device 244 is provided for connecting the cam structure 242. to a drive circuit (not shown). The cam structure 242 comprises a plurality of spaced apart extremities 246. The distance between adjacent extremities 246 is in the range of 10 μm or less.

The structure 242 enables a very strong electric field to be maintained uniformly over an extended area.

The initiation charge (not shown) is deposited directly on top of structure 242. The initiation charge is mixed or combined with finely ground graphite or with an organic semiconductor sensitizer as well as with a binder. The direct contact between the initiation charge and the metal structure 242 causes the initiation charge to heat internally and thereby cause initiation. Alternatively, the initiation charge may have a component, such as an organic semiconductor, which contains an oxidizing agent which reacts chemically in the presence of a sufficiently strong electric field in an exothermic reaction. In this aspect of the invention, a device can operate between a few volts and about 1 kV and can be implemented at limited current of the order of magnitude and pickoamps.

Figure 15 shows a detonator firing element 250, which comprises a semiconductor with a silicon substrate 251 to which is applied or in which a structure is induced which induces a discharge. The structure that induces a discharge comprises a pair of spaced apart tooth-like portions 252 and 468 297 J? 254. The portion 252 comprises a pair of spaced teeth 256. Similarly, the portion 254 comprises a pair of spaced teeth 258. The teeth 256 and 258 are aligned relative to each other and spaced apart to form a pair of discharge slots 260. The structures 252 and 254 each has a connection means 262 and 264 for connection to a drive circuit (not shown).

Teeth 256 and 258 are used to concentrate an electric field in the gaps 260. In electric fields larger than V / um, discharge can occur between the teeth 256 and 258. As soon as the discharge begins, it will continue until the electric energy has been reduced or until the teeth 256 and 258 have been eroded or damage to the crystal lattice has gone so far that the field becomes too low to sustain discharge.

A primary explosive (not shown) can be initiated directly by the discharge between the teeth 258 and 258 or indirectly by means of an exothermic chemical reaction with one layer. which is in contact with the structure which induces the discharge.

An advantage of this embodiment is that a well-defined threshold voltage is achieved as a function of the distance between the teeth 256 and 258 and that the threshold voltage can be varied between a few volts and about 1 kV.

Figure 16 shows a detonator firing element 270. which comprises a light-generating microchip 272 of N-type material with a layer 272A of P-type material. to which year a primary explosive charge 274 has been applied. The explosive charge 274 reacts to light. which is generated by the microchip 272. which may be a composite semiconductor laser or a light emitting device or any suitable light emitting device e.g. a conventional semiconductor device that generates light through plasma effects.

If the light generating microchip 272 is a laser, a sufficiently high energy density can be achieved to initiate the charge 272 directly. If the microchip 272 provides a lower intensity illumination, an optically sensitized pyrotechnic mixture of '468 297 may be used for the charge 274.

Figure 1? shows a different packaging arrangement for a detonator firing element, for providing a detonator.

The detonator firing element is mounted on a metallic conductor frame 276. which in turn is mounted in a detonator capsule 278. A base charge 280 is provided at one end of the detonator capsule 278. The base charge 280 may be an explosive material such as PETN. An igniter charge 282 of suitable explosive material such as a 4: 1 mixture of lead azide and lead stiffener is provided in the vicinity of the base charge 280. The igniter charge 282 is located in close proximity to a primary explosive body 222, 274 of any of the previously described detonator firing elements. designated 300. The igniter charge 282 is positioned by means of a fixing cap 284.

The metallic conductor frame 276, which carries the detonator firing member 300, passes through a suitable plug 286. which blunts the end of the capsule 278, which faces from the end in which the base charge 280 is arranged. The plug 286 further serves to hold the conductor frame in position. The conductor frame 276 has electrical conductors for transmitting an electrical signal to the detonator firing element 300.

The detonator firing element 300 preferably includes control circuits (not shown). of the type shown in Figures 3 and 6 to control the initiations of the primary charge 222. 274 formed in the silicon substrate of the detonator firing element 300 using conventional microelectronics technology. A safety connection 301, which is isolated from the initial charge 222. 274. and which short-circuits the control lines on the conductor frame 276, is provided for safety reasons.

Activation of the energy dissipation device. i.e., the zirconium connection 218. shown in Figure 10 causes the release of energy to activate the charge 222, 274, which then ignites the ignition charge 282. which in turn ignites the base charge 280, which triggers the explosion intended to be initiated by the detonator. It is obvious that the principles of the invention can be expressed in a variety of different embodiments, each of which comprises a miniaturized energy dissipation device formed in combination with an integrated circuit. This approach to the problem allows complex control functions to be performed with built-in safety and foolproof operation at low cost.

The invention has been described with reference to a solid initiation explosive. As stated, the principles of the invention can be used in combination with liquid or gaseous initial charge charges. The detonator firing device for these examples is preferably of the type based on the use of a fusible compound. or a high-voltage discharge. The fusible compound, as it melts, disperses glowing fragments from the compound into the gaseous or liquid initiation explosive charge. which ensures a successful detonation. Highly successful initialization is also achieved with a high voltage discharge. During assembly, the detonator firing element is sealed in a container such as a can 72 in Figure 5. which also encloses the liquid or gaseous initial charge charge. The problem of arranging the explosive charge on the detonator firing element is thus avoided.

The detonator according to the invention and the detonator firing element can be used in connection with any explosive either for military use or for mining purposes or other purposes.

The system proposed by the invention uses large-scale integration through a low-power digital process. which includes a low power energy dissipation device and surge protector to use a highly intelligent detonator chip. This solution with a single chip enclosed in a low-cost housing with a cheap capacitor provides a detonator. which during the period of use can be driven from the cheap capacitor if the wires are cut by stone throwing.

The possible circuit density in VLSI circuits was then used to enable fully bidirectional communications to and from a control computer. The use of a normal computer and highly reliable communications provide a system that can be quickly adapted to suit the needs of individual users.

Exposed locations i.e. energy dissipation devices will be designed to fit in a standard position on all chips and standard packaging technology will be defined.

The detonators can thus be customized using predefined standard components. This corresponds to the use of a technique. developed for semi-standardized integrated circuits for the design of standardized detonators.

The system is such that for each particular system one can exchange one low energy operating point for another with minimal impact on the other system modules. Energy dissipation devices, such as semiconductor connections, electric field generators and light generators can be exchanged for these exposed points.

Claims (15)

10 15 20 25 30 35 468 297 28 PATENT REQUIREMENTS A detonator firing element comprising a suitable substrate for manufacturing an integrated circuit, at least one energy dissipation device, which is arranged on or in a suitable substrate, an explosive substance in the vicinity of the energy dissipation device, which, after being actuated, initiates explosive the substance by dissipating energy, characterized in that it comprises a passivation layer (34: 214; 236) between at least a part of the substrate (20: 212; 231) and at least a part of the explosive. Detonator firing element according to claim 1, characterized in that the energy dissipation device (12) is a selection of a diffusion resistor, an implanted resistor and a resistor element arranged on a surface on or in the substrate, the resistor element being formed of at least one of the following materials: chromium nickel, tungsten, aluminum, zirconium, polysilicon and metal silicides. 3. A detonator firing element according to claim 1, characterized in that the energy dissipation device is a semiconductor element comprising at least one of the following elements: field effect transistor, LED. (225), a transistor, a four layer means, a zener diode and a 4. A detonator firing element according to claim 1, characterized in that the energy dissipation device is a field effect element (90) comprising two separate electrodes (102; 10 4) on the substrate, wherein in use a voltage is applied across the electrodes, thereby generating a electric high power field or to discharge between the electrodes. 10 15 20 25 30 35, g7 6 ”297 Detonator firing element according to any one of claims 1 to 4 in combination with a container (72), characterized in that the explosive is liquid or gaseous and enclosed in the container together with the detonator firing element. Detonator firing element according to any one of claims 1 to 4, characterized in that the explosive (222) adheres to at least one surface saw, or to a surface attached to the substrate, and that an adhesion promoter is provided to improve the cohesion between the explosive and the surface of the substrate. Detonator firing element according to one of Claims 1 to 6, characterized in that the substrate (20; 212) forms a semiconductor element, comprises integrated circuits intended to control the activation of the indoor detonator firing element. A detonator firing element according to claim 7, characterized in that the semiconductor element comprises surge protection means (30) connected to the energy dissipation device. 9. A detonator firing element according to claim 7 or 8, characterized in that the semiconductor element comprises switching means (14) connected to the energy dissipation device. to protect, against induced electric currents and provide precise control of the initiation of the explosive. Detonator firing element according to one of Claims 7 to 9, characterized in that the energy dissipation device is integrated with the semiconductor element. lO 15 20 25 30 35 D 297 .IL CN 80 11. ll. Detonator comprising a container (72), characterized in that a detonator firing element according to any one of claims 7 to 10 is mounted in the container (72) which is arranged to be initiated by said together with an explosive material, explosive substance. 12. A detonator according to claim 11, characterized in that it comprises energy storage means (84) arranged to supply electrical energy to the energy dissipation device and to the integrated circuits. 13. A series detonation system (Figure 7), characterized in that it comprises a number of interconnected detonators according to claim 11 or 12, and means for controlling the firing of individual detonators. 14. A series detonation system according to claim 13, characterized in that the integrated circuits of each detonator firing element comprise communication means which are activated by a signal from the firing control means for transmitting a signal depending on the position of the electronic semiconductor device to the firing control means. 15. A series detonation system according to claim 14, characterized in that a number of detonators are connected in series and, which system comprises a connection unit connected to one end of the series-connected detonators, the communication means for the different detonator firing elements successively transmitting respective status control means to firing means. , and that the connection unit sends the signal to the firing control means to identify the end of the series-connected detonators.