COLLISION DEFORMATION SENSOR USING A SOURCE OF WAVE ENERGY FOR USE IN THE CRUSH ZONE OF A VEHICLE

Abstract: A collision deformation sensor for use within the crush zone of a vehicle consists of first and second spaced apart substrates for mounting to or forming respective vehicle components, with a compressible carrier medium filling the space between the substrates. The carrier medium is formed from a material transparent or translucent to light or other wave energy, and includes wave energy scattering centers dispersed within the medium to create a scattered energy volume. Alternatively the carrier medium forms a hollow cavity, the inside surface of which is coated with a wave energy dispersion coating. A source and receiver of light or other wave energy communicates with the carrier medium. Signal couplings and processors are associated with the source and receiver. The device operates on the principle whereby compression of the space between the substrates increases the intensity of a light or other wave energy, and this increase is detected by the receiver and signal processor, which in turn activates an air bag, or seat belt tightener or the like.

Description: COLLISION DEFORMATION SENSOR USING A SOURCE OF WAVE ENERGY FOR USE IN THE CRUSH ZONE OF A VEHICLE FIELD OF THE INVENTION The present invention relates to sensors for detecting vehicle impact, for the deployment of air bags or other responses to a vehicle collision. The invention further relates to impact detection systems and vehicles incorporating same. In particular, the invention relates to a deformation sensor installed within the crush zone of a vehicle, which operates by sensing changes in intensity of light or other waveform energy, within a carrier medium, wherein the local intensity of the lighting increases in the event of deformation of the medium. BACKGROUND OF THE INVENTION Impact detection devices comprise an important element of the safety system of modern vehicles. The advent of air bags and automatic belt tighteners in particular have given rise to a need for accurate and responsive impact detection means. Desirably, detection means for vehicle use are relatively inexpensive. Further, it is essential that the sensors be highly reliable, and not be adversely affected by corrosion, temperature changes, altitude, etc. Collision or impact sensors conventionally employ an accelerometer located in vehicle mid-body of the passenger compartment to detect rapid changes in vehicle velocity. However, these arrangements do not provide adequate information in respect of the location and severity of a collision event. The design and activation of increasingly sophisticated occupant restraint systems such as multiple air bags and seat belt tighteners render it important to sense the dynamics of an impact event in order to properly control the restraint devices. A greater degree of sensitivity and accuracy may be achieved through the use of crush zone sensors, which can be used to detect abrupt velocity changes within one or more of the impact zones of a vehicle. The crush zones are the regions within the vehicle which experience substantial deformation in the event of an impact, and which typically experiences a greater deceleration than the non-crush zone. The latter zone typically houses the passenger compartment. The crush zones typically comprise the trunk and engine compartments and the exterior regions of the door and side panels. Conventional vehicle impact sensors include "ball-in-tube" sensors and "inertia" sensors. The ball- in-tube type sensor consists of a hermetically sealed housing, which encloses and surrounds a cylinder. A sensing ball-shaped piston is disposed within the cylinder, and the housing is filled with a damping gas. The piston includes electrically conductive elements. The piston resists movement within the cylinder, conventionally by means of a spring. When the device experiences a sufficient velocity change, the force experienced by the piston overcomes the countervailing bias exerted by the spring and displaces the piston within the cylinder. In addition to the force of the spring, the piston is also exposed to a damping force exerted by ambient damping gas, resulting from the pressure differential that exists once the piston has moved a specific distance within the cylinder. If the vehicle deceleration is sufficiently large in magnitude and long enough in duration to overcome both the damping force and the spring-biasing force, the piston will move to a position where contact is made with a circuit that will activate the air bag or other safety system. An inertia type sensor operates on a similar principle, and comprises a moveable element, which is moveable relative to a static element. In one conventional version, an inertia sensor comprises a "rollamatic" type sensor, which comprises a nearly frictionless mechanism consisting of two or more rollers inserted within the loops of a flexible band, with the band acting to turn the rollers whose movement can be directed to perform various functions. The moveable element is held in place by the tension of the band and a surrounding housing. In the event of a collision or other sudden deceleration or acceleration, the resulting force displaces the moveable element. If the force is great enough in duration and magnitude, the moveable element will move a predetermined distance to a pin, which will be hit or dislodged, activating the air bag or other safety system. Various other sensors have been proposed for use within crush zones, including simple electrical switches, electronic pressure switches, and rod and tube sensors. Conventionally, these sensors have been positioned at the outermost extremities of the crush zone. Other deformation centers have been described, particularly for lateral impact situations. These sensors detect either deformation extent or deformation velocity or, in some cases, a combination of both but with very limited resolution. In one aspect, sensors detect the extent of crushing of the vehicle itself as an indicator of the crash severity or velocity change. Such sensors conventionally initiate safety systems if the crush zone deforms to the extent that it makes contact with the sensor, which has been appropriately positioned within the vehicle. Typically, multiple deformation sensors are mounted at various locations within the vehicle. Deformation sensors mounted within the vehicle crush zone conventionally operate by mounting a switch within the crush zone which when the vehicle experiences a sufficient impact, forces two elements of the switch together to create an electrical contact. For example, a fiber optic type switch may be mounted within the contact zone (See U.S. Patent 4,988,862). Alternatively, two spaced apart conductors separated by an elastic member may be mounted within the crush zone, with the conductors contacting each other upon experiencing a sufficient impact. (See U.S. Patent 4,995,639). None of these conventional arrangements are entirely suitable for detecting velocity changes within the crush zone of a vehicle in a manner suitable for sensing all or most potentially injurious accidents. In particular, inertial sensors have been found to trigger air bag restraint systems on short duration acceleration pulses, but not on longer duration pulses. As well, the ball-in-tube type sensor has had little success when responding to vertical and lateral acceleration, and only responds relatively well to longitudinal deceleration. Further, the ball-in-tube sensor may be adversely affected by temperature, with extremes of temperature adversely effecting the viscosity of the damping gas within the sealed housing. A drawback within many prior art sensors resides in the risk of accidental triggering in response to a non-destructive or non-injurious impact. It is desirable to provide a deformation sensor which is integral to the primary structure of the vehicle and will with a high reliability not respond to any event other than an actual deformation of the structural and/or energy absorbing members of the vehicle. It is further desirable to provide a sensor that is highly reliable in adverse environments and relatively inexpensive to mass produce. Superior impact detection to address the above goals may be achieved through the use of a sensor which operates according to light or other wave energy scattering principles, rather than strictly electrical and/or mechanical means. Within applicant's previous PCT International application no. PCT/CA98/00686 there is disclosed a pressure sensor of general application, referred to herein as an "integrating cavity" pressure sensor. This sensor which operates according to the principle whereby the intensity of light or other wave energy dispersed and scattered within an integrating cavity is increased as the region within which the energy is dispersed is diminished. According to this principle, a pressure sensor may comprise a compressible carrier medium of light or other wave energy, containing scattering centers for disbursing the light within the carrier medium. Wave energy source receiving means are associated with the carrier medium to transmit and receive, respectively, the wave energy to and from the carrier medium. The term "light" will for convenience be generally used herein in reference to wave energy of any suitable type. It will be understood that other forms of wave energy including electromagnetic radiation in the non- visible spectra and sound may comprise the wave energy for use in the present invention. The carrier medium of the integrating cavity-type sensor may be enclosed within a flexible envelope or a compressible housing or the like. Pressure applied to the envelope or housing compresses the carrier medium, thereby increasing the intensity of the light within the region surrounding the light source, in proportion to the decrease in volume of the carrier medium. The change in light intensity is detected by the receiver, which transmits the information to a signal processing means. The carrier medium is transparent or translucent to the particular light or wave frequency, and preferably includes multiple light scattering centers evenly disbursed throughout the medium. For example the medium may comprise a translucent foam material. Alternatively, the integrating cavity comprises a hollow chamber, the interior face of the chamber walls having light reflective and dispersive properties which fully diffuse any light entering the chamber to provide the light dispersion function. The enclosure comprises or forms an integrating optical cavity, which is defined as a region or volume either bounded by an enclosure and/or comprising a deformable material with the characteristic whereby illumination within the cavity undergoes multiple scattering reflections or refractions to thereby become effectively randomized and smoothed out in its distribution throughout the cavity. In such the cavity, at the limit, information about the original direction of illumination is eventually lost. An integrating optical cavity may be an air or gas filled enclosure, or may be a volume within a translucent solid such as a cellular matrix that provides optical scattering centers. It is a characteristic of such a cavity that, for a light source with a constant power output, the light intensity within the cavity is a function of the volume of the cavity, the position of the light source and either the reflectance of the walls of the envelope or the density of scattering centers within the carrier medium. A reduction in the volume of the cavity causes a corresponding increase in the light intensity within the cavity. The cavity may be formed with virtually any shape, although certain extreme shapes may not respond ideally. A pressure sensor of this type may take several convenient forms that are suitable for the purposes of the present invention. For example, the sensor may comprise an elongate, flattened member featuring multiple light sources and receivers. Alternatively, the scattering medium may comprise a block of foam shaped to fit within a defined cavity or receiving space. SUMMARY OF THE INVENTION It is an object of the invention to provide a vehicle component comprising a sensing or detector means for detection of a vehicle impact, whereby the risk of accidental triggering is minimized. It is a further object to provide an impact sensor specifically adapted to detect actual deformation of the crush zone of a vehicle or other components of the vehicle, indicative of severe impact. It is a further object to provide an impact sensor which is minimally affected by electromagnetic interference, corrosion, temperature and other variables. It is further object to provide such detection by sensing means that minimize electrical and moving elements and components. In accordance with the objects recited above, the present invention comprises in one aspect a deformation sensor for installation within a vehicle, to detect an impact experienced by the vehicle sufficient to deform a portion of the vehicle. In this aspect, the invention comprises: a) a pressure sensor comprising a compressible carrier medium of wave energy transmitting material having an outer boundary and scattering centers evenly disbursed within the medium; b) a wave energy source coupled to or communicating with the carrier medium, to create a scattered energy volume containing scattered wave energy within the carrier medium; c) a wave energy receiver responding to the integrated intensity of scattered wave energy within the scattered energy volume; d) signal coupling means connected to the wave energy receiver for transferring signal therefrom to a pressure indicator, wherein the region around the wave energy source and the receiver substantially defines the scattered energy volume. Upon displacement of the outer boundary, the dimensional volume of the scattered energy volume changes in response to changes in an externally applied pressure to provide a change in the intensity of the scattered wave energy that a signal is thereby produced to permit the pressure indicator to provide a measure of the applied pressure; and e) first and second spaced apart substrate members, each of which in turn is associated with a corresponding vehicle component within a crush zone of a vehicle, with the carrier medium being retained between the substrate members whereby displacement of the components upon vehicle impact compresses the carrier medium and signals an impact event. Preferably, the wave energy comprises light, and the carrier medium comprises a translucent foam material. In a further aspect, the energy source and receiver comprise a fiber optic light source, associated with a fiber optic receiver in close proximity thereto. In a further aspect, multiple paired fiber optic light sources and receivers are provided within a fiber optic array. Alternatively , the light source may comprise one or more LED units in proximity to the carrier medium, and the receivers may comprise photoreceptors. The LED's and photoreceptors may be mounted to a circuit board in contact with the carrier medium. In a further aspect, the invention comprises a vehicle bumper, having a rigid bumper support comprising the first substrate member, a bumper skin spaced apart from the support and comprising the second substrate member, whereby a hollow region is defined between the bumper skin and support. The hollow region is at least partly filled with an energy absorbing material comprising the carrier medium, which conveniently comprises translucent foam. At least one light source and receiver communicate with the carrier medium. Preferably, the light source and receiver are in close proximity to, in contact with, or embedded within the foam.. Conveniently the source and receiver comprise a linear array of fiber optic or LED light sources and receivers mounted to the bumper support. In one version, fiber optic transmitters and receivers are individually associated with a control module, which comprises a light source communicating with the fiber optic cables. The module further comprises signal coupling means for receiving transmitted light from the fiber optic receivers and signal processing means for converting the intensity of the received light into a signal indicative of deformation of the carrier medium in the region surrounding the energy sources and receivers. Alternatively, the module communicates with a circuit board supporting an array of LED's and photoreceptors in contact with the carrier medium. In a further aspect, the invention comprises a vehicle panel, such as a door panel or other structural element, comprising a rigid frame element and a skin spaced apart therefrom, with the hollow region between the skin and frame element being at least partly filled with the deformable carrier medium, which preferably comprises a translucent foam material. One or more light sources and receivers as described above are mounted within the panel in contact with or communicating with the carrier medium, and preferably mounted to the frame element. A control module as described above is associated with the energy sources and receivers. In a further aspect, the invention comprises a vehicle frame element, comprising a hollow vehicle structural member at least partly and preferably completely filled with said carrier medium, which preferably comprises a translucent foam material. A light source and receiver means, as characterized above, communicates with the carrier medium and is associated with a processor module as characterized above. In a further aspect, the invention comprises a deformation sensor for installation within a vehicle, for detecting compressive forces between two relatively closely spaced vehicle components. In this aspect, the invention comprises a pair of spaced apart parallel plates, with the region between the plates filled with the carrier medium, preferably comprising translucent foam. Each plate is associated with a corresponding vehicle component whereby any convergence of the vehicle components, such as would occur in a collision for example, compresses the interstitial foam between the plates. Preferably, the lateral edges of the hollow region are bounded by constraining members for fully enclosing the space between the plates and retaining the foam fully between the outer plates. One or more light sources and receivers as described above are positioned within the carrier medium or otherwise coupled to or communicating with the carrier medium. The receiver or receivers are linked to a processor module. In a further aspect, the invention comprises a longitudinal deformation sensor, for detection of relative displacement of comparatively widely separated vehicle components. In this aspect, the invention comprises an elongate hollow cylinder, the bore of which is partly filled with the carrier medium. One end of the cylinder is sealed. The carrier medium is retained within the cylinder by a slidable cylinder plunger disposed within the hollow bore of the cylinder and in contact with the carrier medium. One or more light sources and receivers as described above is positioned within the cylinder in contact with or communicating with the carrier medium, and preferably mounted adjacent the base of the cylinder. The cylinder body and bore are each mounted to respective vehicle components. Displacement of the associated vehicle components towards each other displaces the plunger within the cylinder, thereby compressing the carrier medium and signaling an impact event. A processor module associated with the energy sources and receivers may be positioned either within the interior of the cylinder or externally thereof. In a further aspect, the invention comprises a vehicle, having an air bag or other impact response means, and one or more deformation sensors as described above mounted within the vehicle and operatively connected to the response means. In a further aspect, the invention comprises a method for detection of a severe impact against a vehicle sufficient to compress a portion of the vehicle, comprising the steps of: a) providing a deformation sensor as described above within a vehicle linking two vehicle component parts within the crush zone of a vehicle; b) transmitting light or other wave energy through from a source to a deformable carrier medium within the sensor; c) detecting scattered light or other wave energy within the deformable carrier medium by means of said wave energy receiver; d) converting within a processor means said received wave energy into an electrical signal corresponding to the intensity level; e) actuating an air bag or other impact response means upon detection of a change in the intensity of the light or other wave energy within the carrier medium, indicative of converging of the vehicle components in an amount indicative of a severe impact experienced by the vehicle. Although the embodiments specifically described herein are adapted for use with a conventional car or truck, it will be understood that with suitable modifications the invention may be associated with any land, water, air or space craft. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1(a) and 1(b) are schematic sectional views of a portion of a prior art deformation sensor of the type which is adapted for use in the present invention; Figure 2 is a sectional view of a vehicle bumper incorporating the present invention; Figure 3 is a sectional view of a vehicle door panel incorporating the invention; Figure 4 is a sectional view of a vehicle frame member incorporating the invention; Figure 5 is a sectional view of a sensor according to a second embodiment of the invention; Figure 6 is a sectional view of a sensor according to a third embodiment of the invention; Figure 7 is a sectional view according to Figure 6, of a fourth embodiment of the invention; Figure 8 is a schematic view of a portion of a vehicle, namely a vehicle engine compartment and surrounding components illustrating an aspect of the invention; Figure 9 is a schematic view of an aoay of sensors and associated controls and related components; and Figures 10(a) and 10(b) are schematic views of an illumination strip and associated processor components. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention comprises in general terms a deformation sensor mounted within a strategic position within the crush zone of a vehicle. The sensor may be incorporated within a vehicle as an integral component of a functional or structural portion of the vehicle. Figures 1 (a) and 1 (b) show a prior art sensor of the type generally described in PCT/CA98/00686 and known as an "integrating cavity" sensor. The present invention incorporates a sensor of this general type. An integrating cavity pressure sensor 1 comprises in general terms a carrier 2 comprised of a volume of light-scattering material. Conveniently, the material may comprise an open or closed cell translucent foam. Multiple spaced apart light sources 4 provide uninterrupted and fully scattered illumination of a region within the foam. The carrier interior is illuminated by a fiber optic cable 6, one end of which is connected to a light source and the second end terminates within or against the foam body 2. A second optical fiber 8 bundled with the first fiber comprises a light receptor for detection of the intensity of light within the foam. A second end of the receptor communicates with signal processing means 10. The light sources illuminate a region within the interior of the foam with a predetermined intensity, with the light within this region being fully scattered by scattering centers within the foam, such as cellular walls within the foam. The light sources and receivers are associated with a support matrix comprising an elongate illumination strip 6. Compression of the foam increases the intensity within the region by a predetermined amount varying with the extent of deformation, as illustrated schematically in Figure 1 (b). An optic fiber 6 may be associated with a light source comprising a conventional bulb or an LED within the processing means 10, powered for uninterrupted illumination by a vehicle electrical power source or a separate power source. Preferably, a warning light viewable by the vehicle operator is associated with the light source, and indicates to the operator when the light source burns out or otherwise is not operating. Turning to Figure 2, the present invention comprises in one aspect a vehicle bumper 20 incorporating the present invention. The bumper comprises a rigid bumper armature 22, featuring spacers 24 mounted to the vehicle frame (not shown) and an elongate rigid support 26 spanning the arms. A bumper skin 28 is mounted to the armature, and comprises a flexible envelope filled with an energy absorbing translucent foam core 2. An illumination strip 16 is mounted to the bumper support and extends substantially the length thereof. Illumination strip 16 is formed from an array of fibre optic cables, which serve as both light sources and receivers in a staggered array. The optic cables extend into an electronic microprocessor module 10, mounted to the bumper armature. The microprocessor module includes information and signal processing means, described in greater detail below, whereby optical signals from the sensor are converted into electronic signals. A power and communications connection 32 connects the microprocessor module 10 with a power source, not shown, and one or more air bags or other safety devices (not shown), as will be described in greater detail below. The module also includes one or more light emitters for transmission by the light source fiber optic cables. Figure 3 illustrates a vehicle door panel 40 incorporating a pressure sensor according to the present invention. The panel comprises a reinforcing bar 42 at an inside portion of the panel, and an outer skin 44. Energy absorbing translucent foam 2 is positioned within the skin. An illumination strip 16 is mounted to the reinforcing bar 42, and in communication with the energy absorbing foam 2. Illumination strip 16 is formed from optic fibers as described above. The illumination strip 16 communicates with a microprocessor module 10 having the same features as described above. The microprocessor module communicates with a power source and air bags or like safety devices, not shown. Figure 4 illustrates a structural frame element 50 of a vehicle incorporating a pressure sensor. The frame element may comprise any selected vehicle frame member such as a vehicle roll bar, door pillar or other member. The frame member comprises a rigid outer shell 52, having a hollow space therein. The interior of the member is filled with a light scattering foam. Disposed within the interior of the frame, and extending substantially or partially the length of the frame member is an illumination strip as described above. A microprocessor module 10 is linked to the strip, and is mounted either directly to the frame member, or elsewhere within the vehicle. The module is in turn linked to a power source and an air bag or other like safety feature. Figure 5 illustrates a first version of a non-integral deformation sensor 60 for mounting between two vehicle components. For example, such a sensor may be mounted between two vehicle frame members for detecting a converging of the members indicative of a vehicle impact. This version of the sensor is referred to herein as a "lateral" sensor, since it has a broad, shallow region of compression. In this version, the sensor has a first elongate axis and second relatively short transverse axis. The sensor primarily detects deformation along the transverse axis. The sensor comprises a cell, composed of first and second spaced apart parallel rigid plates 62, with the side edges of the plates 62 bounded by compressible or resilient wall 64 to define an enclosed interior space between the plates. The interior space is substantially filled with an optical foam core 2. An illumination strip 16 is housed within the interior space, in contact with the foam. Mounting brackets 66 on the plates permit the respective plates to mount to two relatively closely spaced vehicle components, wherein relative displacement of the vehicle components indicates a severe impact. As described above, a microprocessor module 10 is linked to the fiber optic array, and is in turn linked to a power source and one or more air bags or the like. The module may be mounted directly to the vehicle component, or elsewhere within the vehicle. Figure 6 illustrates a second type of non-integral sensor, comprising longitudinal deformation sensor 70 having an elongate axis, which may be mounted within the crush zone of a vehicle. This second sensor type may be mounted between relatively widely spaced frame elements within the engine compartment, whereby upon deformation of the engine compartment, the frame elements are displaced towards each other, with the displacement being detected by the sensor. In this embodiment, the deformation sensor comprises a rigid cylindrical hollow cylinder 72, one end of which is capped by a cap 74, which in turn is sealed to the cylinder by means of a seal 76. A tab 78 extends from the cap for mounting of the first end of the cylinder to a first component within the vehicle. A plunger 80 is slidably disposed within the cylinder, with the outwardly-extending end of the plunger featuring a second tab 82, for mounting to a second component of the vehicle. The plunger is retained within the cylinder by means of an annular seal 84 disposed within the second, open end of the cylinder, and contacting the plunger. The hollow interior base of the cylinder, between the cap and the plunger, is filled with a light scattering foam 2. An illumination strip 16 as generally described above is disposed within the hollow interior space, and conveniently may be mounted to a rigid interior plug 86 mounted within the cylinder spaced apart from the cap 74. The illumination strip is operatively connected to a microprocessor module 10, as described above, which in turn is associated with a power source and one or more air bags or the like (not shown). The microprocessor module is conveniently mounted within the interior of the cylinder, within a space between the plug 86 and cap 74. When the vehicle experiences a sufficient impact to deform the crush zone, the plunger is urged inwardly within the cylinder, thereby compressing the optical foam and increasing the light intensity within the foam by a proportionate amount. Turning to Figure 7, a variant 90 of the embodiment illustrated in Figure 6 is disclosed, wherein the fiber optic aoay is mounted directly to the base of the cylinder 72, thereby dispensing with the plug 86 shown in Figure 6. In this version, the fiber optic connection 92 between the microprocessor and the fiber optic array extends through the cylinder wall, with the microprocessor module 10 being mounted externally of the cylinder, within the vehicle compartment. A fiber optic connector 94 joins together a first fiber optic line 96 leading to the fiber optic array 16 within the cylinder, to a second fiber optic line 98 leading to the microprocessor module. Turning to Figure 8, a typical installation for an array of deformation sensors within the crush zone of a vehicle 100 is illustrated, in this case a vehicle engine compartment and surrounding components. The crush zone comprises a vehicle frame 102, bumper armature 104 and automobile body skin 106. The engine is mounted to the vehicle frame. One of the vehicle wheels 108 is illustrated, with the second wheel being removed for clarity. One or more side- mounted longitudinal type deformation sensors 70 join the vehicle frame with the body shell, in the region surrounding the front wheel. Further, multiple lateral type sensors 60 are positioned strategically within and around the engine compartment, for example between the engine and frame at the front portion of the engine, between the rear of the engine and a transverse frame element, and between the engine radiator and the front bumper armature. With this arrangement, a severe frontal or lateral impact against the crush zone of the vehicle will trigger one or more of the deformation sensors, for signaling impact information to the central processing unit, as described below. Figure 9 is a schematic drawing illustrating an array of deformation sensors, a central control unit and an air bag or the like. An array of deformation sensors 160, which may be of any one or more of the variants disclosed herein, are mounted strategically within one or more crush zones of a vehicle. Each sensor 160 is associated with a corresponding microprocessor module 10. The microprocessor modules are each connected to a common power source 120, which conveniently comprises the vehicle battery, and a common central processing unit 122. The central processing unit is in turn connected to one or more air bags 124, seat belt tightening means 126 or other impact response means. Preferably, the central processing unit controls the air bags or the like in such a manner that the air bags are selectively deployed in response to the direction and/or extent of impact. Accordingly, a lessor impact will result in a reduced air bag inflation amount. Further, an impact received from a particular direction may result in triggering of the air bags only on a signal side of the vehicle. For example, an impact experienced at one side of a bumper might result in a corresponding signal being transmitted from the detectors at that side of the bumper. Depending on the severity of the impact, response devices might be deployed only at one side. Alternatively, varying responses may be triggered, depending on the direction and severity of impact. For example, any combination of belt tightening and single or multiple air bag deployment may be triggered. Figures 10(a) and 10(b) illustrate in schematic form two variants of the illumination strip, shown as reference 16 in connection with the embodiments described above and associated control means shown as reference no. 10. Figure 10(a) illustrates a fiber optic mediated illumination and detection arrangement, wherein the strip comprises a fiber optic ribbon cable 140, comprising an aoay of transmitter and receiver fiber optic pairs. The ribbon cable 140 enters the processing means 10. The emitter fibers 6 communicate with an LED light source 142 within the processing means 10, and the receiver fibers 8 are coupled to a photo detector array 144. The signals from the photo detector array pass through an analog/digital converter 146, which in turn communicates with a micro controller 148 for interpretation of signals communicated by the array 144. The micro controller communicates with a conventional air bag controller, not shown. The above elements are powered by a power source 150. Turning to Figure 10(b), a non-fiber optic mediated arrangement is illustrated. In this version, the illumination strip comprises a rigid or flexible circuit board 152. The circuit board supports an array of LED/photo detector pairs 154, which in turn communicate with a multiplexer 156. Signals from the multiplexer are transmitted through an analog/digital converter into a microcontroller, and subsequently an air bag controller, as above. The above elements are powered by a power source 150 in the same manner as above. Either of the arrangements of the illumination strips shown in Figures 10(a) and 10(b) may be adapted for inclusion in any of the sensor arrangements described herein. The embodiments illustrated in Figures 5 and 6 are intended specifically to comprise rate or attitude configurations. Rate sensors detect rate of turn by detecting rotational accelerations or centrifugal accelerations. Attitude or inclination sensors operate by detecting off-axis gravitational accelerations. For automotive applications, these sensors are tuned for optimal operation at accelerations in the order of +/-lg. Although the present invention has been described herein by way of detailed descriptions of prefeoed embodiments of the invention, it will be understood by persons skilled in the art to which this invention relates that departures and variations of these embodiments will be encompassed by the present invention. The full scope of the invention, as defined in the claims, embraces such departures and variations.

Claims: CLAIMS: 1. A collision deformation sensor for vehicles, comprising: a) a pressure sensor comprising a compressible carrier medium of wave energy transmitting material having an outer boundary having wave energy scattering centers disbursed within the medium; b) a wave energy source coupled to the carrier medium, to create a scattered energy volume containing scattered wave energy within the carrier medium; c) a wave energy receiver responding to the integrated intensity of scattered wave energy; d) signal coupling means connected to the wave energy receiver for transferring signal therefrom to a pressure indicator indicative of changes in intensity of wave energy within said scattered energy volume, said signal being in response to changes in an externally applied pressure to said carrier medium to provide a measure of the applied pressure; and e) first and second spaced apart substrate members, each of which in turn may be mounted to or comprise a cooesponding vehicle component within a crush zone of a vehicle, with said carrier medium being retained between said substrate members, said components being arranged whereby displacement of said substrate members together upon vehicle impact compresses said carrier medium and signals an impact event. 2. A sensor as defined in claim 1, wherein said wave energy source and receiver comprise respectively a source and receiver of electromagnetic radiation within approximately the visible light range. 3. A sensor as defined in claim 2, wherein said energy source and receiver comprise respectively a fiber optic light source and receiver. 4. A sensor as defined in claims 2 or 3, wherein said light source and receiver comprise a generally linear array of pairs of light sources and receivers. 5. A sensor as defined in claim 2, wherein said light source and receiver comprise an LED and photo detect receptor, respectively, mounted to a circuit board in contact with the carrier medium. 6. A component of a crush zone of a vehicle, comprising: a) a base member; b) a moveable member spaced apart from said base member, said base and moveable members configured for converging together upon experiencing a vehicle impact; and c) a pressure sensor between said base and moveable members, said pressure sensor comprising: i) a compressible carrier medium of wave energy transmitting material having wave energy scattering centers disbursed within the medium, said carrier medium being disposed between said base and moveable members; ii) a wave energy source coupled to the carrier medium to create a scattered energy volume containing scattered wave energy; iii) a wave energy receiver responding to the integrated intensity of scattered wave energy; and iv) signal coupling means connected to the wave energy receiver for transferring signal therefrom to a pressure indicator indicative of changes in intensity of wave energy within said scattered energy volume, said signal being in response to changes in an externally applied pressure to said carrier medium resulting from convergence of said base and moveable members to provide a measure of the applied pressure and signal an impact event. 7. A component as defined in claim 6, wherein said wave energy source and receiver comprise respectively a source and receiver of electromagnetic radiation within approximately the visible light range. 8. A component as defined in claim 7, wherein said energy source and receiver comprise respectively a fiber optic light source and receiver. 9. A component as defined in claims 7 or 8, wherein said light source and receiver comprise a generally linear array of pairs of light sources and receivers. 10. A component as defined in claim 7, wherein said light source and receiver comprise an LED and photo detect receptor, respectively, mounted to a circuit board in contact with the carrier medium. 11. A vehicle component as defined in claim 6, comprising a vehicle bumper. 12. A vehicle component as defined in claim 11, wherein said base member comprises a bumper armature and said movable member comprises a bumper skin, said carrier medium comprising a compressible foam material at least partly filling the space between said armature and skin. 13. A vehicle component as defined in claim 6, comprising a vehicle door panel, said base member comprising a support structure, said moveable member comprising a skin, there being an interior volume therebetween substantially filled with said carrier medium. 14. A vehicle component as defined in claim 6, wherein said base member comprises a portion of a vehicle frame, and said moveable member comprises a portion of said vehicle skin spaced apart from said frame, said carrier medium comprising compressible foam at least partly filling said space between said frame and skin. 15. A vehicle component as defined in claim 6, comprising a vehicle frame element, said frame element comprising a rigid skiri and an interior space, and said carrier medium substantially filling said space, said source and receiver being in communication with said medium. 16. A vehicle incorporating at least one deformation sensor as defined within any of claims 1 - 5. 17. A method for detection of an impact against a vehicle sufficient to compress a portion of the vehicle, comprising the steps of: a) providing a deformation sensor as claimed in claim 1 within a vehicle linking two component parts within the crush zone of a vehicle; b) transmitting light or other wave energy through from a source to a deformable carrier medium within the sensor; c) detecting scattered light or other wave energy within the deformable carrier medium by means of said wave energy receiver; d) converting within a processor means said received wave energy into an electrical signal corresponding to the intensity level; e) actuating an air bag or other impact response means upon detection of a change in the energy level indicative of converging of the vehicle components in an amount indicative of a severe impact experienced by the vehicle.

Inventors: BALDWIN LORNA H, REIMER ERNEST M, BALDWIN, LORNA, H., REIMER, ERNEST, M.
Applicants: BALDWIN LORNA H, CANPOLAR EAST INC, REIMER ERNEST M, BALDWIN, LORNA, H., CANPOLAR EAST INC., REIMER, ERNEST, M.
Application year: 1999
Main classification: B60R21
IPC codes: B60R21, B60R22, G01L5