Ammunition and explosives – Igniting devices and systems – Electrical primer or ignitor
Reexamination Certificate
2000-06-19
2001-11-20
Jordan, Charles T. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Electrical primer or ignitor
C102S202500, C102S202600, C102S202700, C102S202400, C102S202800
Reexamination Certificate
active
06318267
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an integrated circuit configuration and to an ignition unit.
European Patent EP 0 471 871 B1 discloses an occupant protection system for motor vehicles in which a control unit disposed in a centralized manner in the motor vehicle controls, via a data bus, igniters disposed in an occupant protection device such as an airbag, a seat belt pretensioner, etc. Each igniter has a resistance heating wire that is embedded in an ignition material and is connected to an energy storage capacitor via a controllable power stage. A control circuit of the igniter receives messages communicated via the data bus and switches the power stage on in the event of an ignition command. With the result that the energy stored in the capacitor in the form of a current heats the resistance heating element and thus causes the ignition material to explode. The liberated energy in turn releases gas that is compressed in pellets and fills an airbag, for example.
Capacitors have been able to be integrated in silicon for a number of years. To date, however, the integrated capacitors have been distinguished by a relatively low capacitance. The applicant therefore proposed an integrated circuit configuration having a capacitor whose storage capacitance approaches that of conventional, discrete capacitors (see V. Lehmann et al., titled “A Novel Capacitor Technology Based On Porous Silicon” in Thin Solid Films, 276 (1996), Pages 138-142). In this case, pores are produced electrochemically in a semiconductor substrate—called a semiconductor layer below. The pores are covered with a dielectric layer and a polysilicon layer. The semiconductor layer and the polysilicon layer form capacitor electrodes. The capacitance of known integrated capacitors is significantly increased on account of the formation of pores.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an integrated circuit configuration and an ignition unit, that overcome the above-mentioned disadvantages of the prior art devices of this general type, which has a small ignition unit containing a capacitor and an ignition element configured as a heating resistor, which ignition unit can be produced with a small outlay.
With the foregoing and other objects in view there is provided, in accordance with the invention, an integrated circuit configuration, including:
a semiconductor layer functioning as a first capacitor electrode, the semiconductor layer having a porous region formed therein;
a dielectric layer disposed on the semiconductor layer; and
a further semiconductor layer functioning as a second capacitor electrode disposed on the dielectric layer, the first capacitor electrode, the dielectric layer and the second capacitor electrode form a capacitor in the porous region of the semiconductor layer, the further semiconductor layer having a region tapered in its cross-section serving as an ignition element connected to the capacitor.
In accordance with an added feature of the invention, the further semiconductor layer is a polysilicon layer.
In accordance with an additional feature of the invention, the semiconductor layer has a nonporous region, and the region of the further semiconductor layer being a tapered region extending over the nonporous region of the semiconductor layer.
In accordance with another feature of the invention, there is a contact area disposed on an area of the semiconductor layer that is free of the dielectric layer and the further semiconductor layer.
In accordance with a further added feature of the invention, the semiconductor layer has a nonporous region, and including a further contact area disposed on the further semiconductor layer above the nonporous region of the semiconductor layer.
In accordance with a further additional feature of the invention, the ignition element has a resistance in a range of from 0.5 to 20 ohms.
In accordance with another added feature of the invention, the capacitor has a capacitance greater than 0.8 &mgr;F.
In accordance with another additional feature of the invention, the capacitor has a capacitance of less than 0.8 &mgr;F.
In accordance with a concomitant feature of the invention, the semiconductor layer has a nonporous region, and including a insulating layer disposed between and isolating the semiconductor layer from the further semiconductor layer, and the insulating layer is a partial layer of the dielectric layer.
With the foregoing and other objects in view there is further provided, in an occupant protection device of a motor vehicle in accordance with the invention, an ignition unit for igniting the occupant protection device, the ignition unit including:
a semiconductor layer functioning as a first capacitor electrode, the semiconductor layer having a porous region formed therein;
a dielectric layer disposed on the semiconductor layer;
a further semiconductor layer functioning as a second capacitor electrode disposed on the dielectric layer, the first capacitor electrode, the dielectric layer and the second capacitor electrode forming a capacitor in the porous region of the semiconductor layer;
an ignition material; and
the further semiconductor layer having a region tapered in its cross-section and serves as an ignition element connected to the capacitor, the capacitor storing electrical energy for heating the ignition element, the ignition element, in an event of current throughflow, igniting the ignition material thermally coupled to the ignition element.
In accordance with a preferred embodiment of the invention, the capacitor has a capacitance dimensioned such that energy stored in the capacitor is less than a quantity of energy that is required for igniting the ignition material. Alternatively, the capacitor can have a capacitance dimensioned such that energy stored in the capacitor suffices for igniting the ignition material.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an integrated circuit configuration and an ignition unit, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
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“Thin solid films” (Lehmann et al.), Siemens AG, Department ZFE, 81730 München, Germany, pp. 138-142, as mentioned on p. 2 of the specification.
Rothleitner Hubert
Swart Marten
Greenberg Laurence A.
Jordan Charles T.
Lerner Herbert L.
Semunegus Lulit
Siemens Aktiengesellschaft
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