Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
  • B60R21/01512—Passenger detection systems
  • B60R21/01542—Passenger detection systems detecting passenger motion
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
  • B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
  • B60N2/002—Seats provided with an occupancy detection means mounted therein or thereon
  • B60N2/0021—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement
  • B60N2/0024—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement for identifying, categorising or investigation of the occupant or object on the seat
  • B60N2/0026—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement for identifying, categorising or investigation of the occupant or object on the seat for distinguishing between humans, animals or objects
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
  • B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
  • B60N2/002—Seats provided with an occupancy detection means mounted therein or thereon
  • B60N2/0021—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement
  • B60N2/0024—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement for identifying, categorising or investigation of the occupant or object on the seat
  • B60N2/0027—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement for identifying, categorising or investigation of the occupant or object on the seat for detecting the position of the occupant or of occupant's body part
  • B60N2/0028—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement for identifying, categorising or investigation of the occupant or object on the seat for detecting the position of the occupant or of occupant's body part of a body part, e.g. of an arm or a leg
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
  • B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
  • B60N2/002—Seats provided with an occupancy detection means mounted therein or thereon
  • B60N2/0021—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement
  • B60N2/0024—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement for identifying, categorising or investigation of the occupant or object on the seat
  • B60N2/0029—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement for identifying, categorising or investigation of the occupant or object on the seat for detecting the motion of the occupant
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
  • B60R21/01512—Passenger detection systems
  • B60R21/01516—Passenger detection systems using force or pressure sensing means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
  • B60R21/01512—Passenger detection systems
  • B60R21/0153—Passenger detection systems using field detection presence sensors
  • B60R21/01532—Passenger detection systems using field detection presence sensors using electric or capacitive field sensors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
  • B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
  • B60N2/002—Seats provided with an occupancy detection means mounted therein or thereon
  • B60N2/0021—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement
  • B60N2/0023—Seats provided with an occupancy detection means mounted therein or thereon characterised by the type of sensor or measurement for detection of driver fatigue
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
  • B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
  • B60N2/24—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles for particular purposes or particular vehicles
  • B60N2/26—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles for particular purposes or particular vehicles for children
  • B60N2/266—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles for particular purposes or particular vehicles for children with detection or alerting means responsive to presence or absence of children; with detection or alerting means responsive to improper locking or installation of the child seats or parts thereof
  • B60N2/267—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles for particular purposes or particular vehicles for children with detection or alerting means responsive to presence or absence of children; with detection or alerting means responsive to improper locking or installation of the child seats or parts thereof alerting means responsive to presence or absence of children
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
  • B60N2210/00—Sensor types, e.g. for passenger detection systems or for controlling seats
  • B60N2210/10—Field detection presence sensors
  • B60N2210/12—Capacitive; Electric field
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R2021/003—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks characterised by occupant or pedestian
  • B60R2021/0039—Body parts of the occupant or pedestrian affected by the accident
  • B60R2021/0048—Head
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R2021/01006—Mounting of electrical components in vehicles

Definitions

• the present invention relates to vehicle occupant sensing methods and apparatuses
• Sensor technologies known in the art include beam-emitting devices such as infrared, ultrasound microwave, and capacitance- based sensors, the latter being able to fill a volume and respond to the different conductivity of the -2- occupant versus that of air and surrounding materials
• beam-emitting devices such as infrared, ultrasound microwave, and capacitance- based sensors, the latter being able to fill a volume and respond to the different conductivity of the -2- occupant versus that of air and surrounding materials
• the present invention is of a capacitive sensor array comprising a plurality of capacitive sensors, each of the sensors comprising two adjacent electrodes formed on a single surface of a dielectric substrate
• each capacitive sensor is installed in a seat, floor, door panel, dashboard, roof, roof supports, or steering wheel of a vehicle to sense occupant presence or position
• the invention is further of a signal device for a vehicle airbag system or other safety device, the device comprising a voltage threshold, the threshold selected from a range of output voltages created by a capacitive sensor constructed of dual adjacent electrodes formed on a single surface of a dielectric substrate, the range of voltages comprising a continuum from a maximum voltage when sensing fields are undisturbed by proximity of a person to a minimum voltage when a person is adjacent to the capacitive sensor
• the invention is additionally of a capacitive sensor array comprising a plurality of capacitive sensors with dual adjacent electrodes formed on a single surface of a dielectric substrate, the array installed in a vehicle in a manner to detect a vehicle occupant's head position relative to a seat headrest, and the array connected to adjustment means for adjusting seat headrest position to achieve a desired proximity of the headrest to the occupant's head
• the invention is also of a device for determining head position of a vehicle occupant by reference to proximity v es obtained from an array of three or more proximity sensors, the device employing a geometric relationship of the sensors and the occupant's head, the device optionally employing an adjustment of the proximity values to adjust for a difference between a head surface proximity point and a head interior point, the device optionally being used to detect occupant impairment, to detect relative risk to the occupant caused by occupant's possibly dangerous position, or to enable the occupant to perform tasks by undertaking predetermined movements of the head -3-
• the invention is still further of a device for detecting vehicle operator impairment, the device comprising means for determining phase shifts of vehicle motion and operator head motion
• the invention is additionally of a vehicle occupant sensing system employing one or more capacitive sensors and one or more weight sensors, the one or more capacitive sensors comprising dual adjacent electrodes formed on a surface of a dielectric substrate, and optionally wherein the capacitive sensors is positioned in a roof, dashboard and/or seat, and optionally wherein the weight sensor is positioned in a seat
• the invention is also of a vehicle airbag system comprising an occupant sensing system and an airbag inflation means, the occupant sensing system comprising one or more capacitive sensors positioned adjacent a roof, and optionally comprising means to detect occupant weight the airbag inflation means becoming armed upon the capacitive sensors outputting a signal indicating presence of an occupant and receiving a signal from the weight sensing means indicating presence of an occupant
• the invention is further of a capacitive sensor comprising a plurality of electrodes formed on a single surface of a dielectric substrate, the electrodes being separated by grounded areas, the substrate additionally comprising a grounded area on an opposite surface from the electrodes, the opposite-side grounded area elect ⁇ cally connected to grounded areas which separate the electrodes
• the substrate encompasses all or a portion of at least two adjacent sides of a rectangle
• the invention is yet further of a capacitive sensor comprising at least two adjacent electrodes formed on a single surface of a dielectric material and electronic parts electrically connected to the electrodes, wherein the electronic parts are installed on an opposite surface of the dielectric material or on a separate dielectric material which is adhered to the capacitive sensor dielectric material
• Primary objects of the present invention are to provide for enhanced safety and operability of automated systems within passenger vehicles -4-
• Fig 1 is a schematic of the adjacent electrode capacitive sensor of the invention in a steering wheel airbag cover
• Figs 2(a) and 2(b) are back and side views of a capacitive sensor of the invention with a tear seam and electronic parts on a side facing the occupant,
• Fig 3 is a schematic of alternate capacitive sensor locations of the invention on the passenger side of a vehicle
• Fig 4 is a schematic of capacitive sensors used in combination with weight sensors
• Fig 5 is a plot of voltage response versus occupant proximity showing voltage thresholds employed by the invention, -5-
• Fig 6 is a schematic of an array of roof-mounted sensors of the invention connected to the seat headrest adjusting mechanism
• Fig 7 is a schematic of an embodiment of the invention to activate the vehicle's horn by proximity switch
• Fig 8 is a schematic of an "L" shaped capacitive occupant sensor of the invention seen from the side facing the occupant
• Fig 9 is a schematic of "L" sensors of the invention configured around a sunroof, seen from the side facing the occupant,
• Fig 10 is a schematic of an electrode arrangement of the invention using two frequencies and opposite positioning of drive versus receive electrodes
• Figs 11 (a)-(c) are cross-section, top, and bottom views of preferred electronics parts placement on a substrate side opposite from the adjacent electrodes,
• Fig 12 is a cross-section view of placement of the electronic parts on a separate circuit board from the dielectric substrate supporting the electrodes
• Fig 13 is a plot of a typical response curve for a sensor of the invention
• Fig 14 illustrates an example sensor placement to perform tnangulation according to the invention
• Fig 15 is a schematic of an "+" shaped embodiment of the invention -6-
• the capacitance sensor may consist of
• This last capacitive sensor is believed to be advantageous because the sensing field is controlled and less subject to stray interference or parasitic capacitances created by other objects in the vehicle
• this sensor can be employed in arrays such that the sensing fields ove " in a fashion to completely fill the desired sensing volume
• Such a sensor can be placed in a * ay in the roof of a vehicle as shown in applicant's U S Patent No 5,602,734 and related applicatu-.is, can be employed individually in the designated locations, or can utilize multiple locations in any desirable combination, such as door seat bottom, and seat back, dashboard, door, and seat back, seat bottom and seat back, and the like
• the sensor fields extend inward from the plane of the capacitive sensor, toward the occupant's position in the vehicle
• a single sensor 5 installed on the inner surface of the steering wheel 1 airbag cover 2 can switch the output of the airbag system according to the proximity of the human body If a driver's
• the senor 5 can be installed on the dashboard 7 facing the seat occupant If the occupant is not within the sensing fields, the airbag system (not shown) is activated However, if the occupant moves into a position close to the airbag door (not shown), the system is either deactivated or is activated at a reduced inflation level
• two or more sensors 5 are employed, one on the face of the dashboard 7 in front of the passenger seat 102, and one or more sensors 5 are installed in the roof 101 above the passenger seating position
• the sensor 5 in the dashboard 7 determines if a person or a baby in a childseat (not shown), is nearby Simultaneously the roof sensor(s) 5 determine if a normally seated person is present, by sensing the person's head (not shown) If both the roof sensor(s) and the dashboard sensor indicate proximity of a person, a logic operation determines the occupant is an adult whose knees or legs are close to the airbag, and normal airbag operation is enabled If only the dashboard sensor indicates a person in proximity, the logic operation determines the person is an infant in a rear-facing child seat and the airbag is disabled
• adjacent electrode capacitive sensors 5 in the interior door 104 or in the floor 103 to accomplish occupant sensing -8-
• the invention can further include analysis of change in voltage output from the roof and/or dashboard sensors to detect motion of the occupant caused either by normal human actions or by severe braking such as a panic stop In the latter instance, the logic operation can determine approximate occupant position relative to the airbag door at the moment of impact, allowing optimum response by the airbag system.
• the invention may also be employed in combination with one or more other technologies
• the capacitive sensors 5 may be installed in the interior roof 101 and in the dashboard 7, together with a weight detecting device 9 located in the seat 102, to reliably discriminate adults, children, infants, and inanimate objects in the seat
• This sensor configuration is better able to detect a small infant in a child seat which is positioned rear-facing on the front passenger seat, thereby disabling the airbag, or triggering a relatively small amount of inflation force
• the invention can employ additional capacitive coupling sensors in the roof, seat, IP or door to offer even greater discrimination and reliability of detection, and of course the user can select Yes/No thresholds that differ from those above to alter the capabilities of the system
• the airbag system may employ the capacitive sensors 5 in the roof 101 as the primary occupant sensing system, in combination with a weight sensor 9 in the seat, as a backup/confirmation occupant sensing system
• the sensing system looks at occupant characteristics from two perspectives - capacitance and weight, in the roof and in the seat
• the capacitive sensor voltage output of the invention when no human body is present in the immediate vicinity, is a predetermined maximum voltage 11
• the presence of a human body causes the voltage output to decrease This decrease in voltage is detectable, and corresponds in a known manner to proximity of the human body If the voltage decreases below a certain threshold 10, the safety system is enabled, disabled, and/or activated at an appropriate level of response
• an array of several sensors with overlapping sensing fields can determine the precise position of the person, as previously disclosed in applicants' pending applications
• the capacitive sensor can also be employed to improve occupant protection in crashes which do not require airbag deployment such as rear-end impacts As shown in Fig 6, in a motor vehicle the seat is designed to absorb these crash forces, particularly in regard to minimizing whiplash by providing a headrest 10G Often this is manually adjustable to accommodate the full range of possible occupant heights Unfortunately, many occupants forget to adjust the headrest height, and thus risk whiplash injury if a rear end impact occurs
• the Z-coordinate can be fed to a headrest height adjusting mechanism 12, to accomplish automatic continuous adjustment of height, to match the head height of the occupant
• the means of triangulating head position using proximity data from three roof-mounted capacitive coupling sensors can be achieved using either trigonometry or analytic geometry
• This solution is -1 1 - simplified by placing the three sensors so that one side of the triangle thus formed parallel to the vehicle x-axis (direction of motion)
• the most advantageous triangle shapes are equilateral, or isosceles with the base parallel to the x-axis
• sensor output voltage varies as a function of the distance from the sensor to an occupant's head (the "target")
• target the distance from the sensor to an occupant's head
• the change in the sensor output voltage with respect to target proximity is a nonlinear response, best fit by an exponential capacitance charge function of the form
• Fig 13 shows a typical response curve for one of the sensors
• the plot is a fit to data samples taken both orthogonal to the sensor and at two lateral offsets of about 10 inches
• the vertical spread of samples at specific distances is a rough measure of the slight distortion of the sensor field from a perfectly hemispherical shape towards one that has a teardrop shape
• sensor output voltage increases as range to target increases, leveling off at a maximum value -- the limiting range
• the constants for the curve in Fig 13 are typical for the 6 to 8 inch diameter sensors currently in use
• A is the "empty field" voltage limit
• B is a function of the -12- signal processing gain
• C is a function of sensor geometry and the capacitative environment of the installation
• constants A, B and C are the offset, gain, and decay, respectively
• the invention permits using single sensors or a pair of sensors, and in these situations voltage thresholds can be used to create presence-absence signals or "zoned" outputs.
• the threshold(s) can be set experimentally and the transform functions for the sensors (the three constants) do not need to be known and are not used except during system design
• Sensors of the invention are preferably used to triangulate head position for use by air bag deployment logic and to address the problem of the detection of "drowsy drivers"
• the sensor voltages are digitized and the inverse transform function is applied to obtain a range-to-target value (proximity) for each of the (preferably) three sensors
• a CPU or like controller is used to digitize the sensor voltages, apply the transform function, and perform a tnangulation process
• One implementation of the process is a "brute force" trigonometric solution, which is not reproduced here because there are simpler solutions
• the system architecture preferably incorporates an imbedded controller to perform the tnangulation and the cost of this controller may be minimized by eliminating or minimizing the need for the trigonometric functions and other advanced mathematical operators
• One may implement a general solution designed for any 3-sensor triangle in any orientation However, by using only an equilateral or isoceles sensor triangle in a specific orientation, one can greatly simplify the tnangulation process and use analytic geometry to eliminate the need for trigonometric functions
• a pyramid with a triangular base The apex of the pyramid is the target
• the base is an equilateral triangle, with a sensor at each of its three “corners”
• Each "edge" of the pyramid, sensor-to-apex, is a proximity distance
• the sides of the base, sensor-to-sensor, are equal (the side length S of the base triangle)
• Fig 14 shows a base triangle in the preferred orientation
• the XY coordinates of each sensor are shown
• the pyramid is inverted -- the base is in the headliner and the apex is at the occupant's head
• the example of Fig 14 has a side length of 198, chosen so that the height of the triangle (the Y-coordinates for S2 and S3 in this o ⁇ entation) come out nearly even The triangle height is actually
• r sqrt(dx 2 + dy 2 + dz 2 )
• Step 1 - three sensor voltages are transformed to proximities using the function
• the required math operators are only the natural log and the square root
• the log transformation can be accomplished via a look-up table
• Noise in the input signal is typically on the order of 5 to10 mV for a +-5 volt system, and that resulting XYZ coordinates are accurate to about 1 millimeter, given this signal-to-noise value It is preferred to maintain this level of accuracy if "micromotion" of an operator's head is being analyzed
• tnangulation implementation is to convert part or all of the voltage/proximity transform function, and the tnangulation algorithm, from software to hardware This is accomplished using readily available electronic devices including operational amplifiers, log amplifiers, and precision multipliers This can eliminate the need for a microprocessor -- making the head XYZ coordinates available as analog signals to the vehicle's airbag controller, or to the sleep- detecting circuitry Alternatively, an inexpensive controller can be used to digitize XYZ coordinates and report these via a serial link
• the capacitive coupling sensors installed in the vehicle roof detect the surface of the occupant's head
• the tnangulation algorithm computes the location of a point inside the head mass This difference is reconciled by the transform function, which adds the average head radius ( 3 0" to 3 5") to the head proximity value
• Head XYZ coordinates are also used for detection of driver impairment based on head motion, as disclosed in PCT Application No PCT/US96/14060 which discloses two examples of head position-time profiles for detection of an impaired operator condition a nodding-off profile, and a lack of head motion profile
• a third profile of impairment is achieved by comparison of the frequency of head motion and frequency of vehicle roof motion, caused by vehicle vibration Vehicle x and/or y-axis roof motion can be determined by two 90-degree offset micromachined accelerometers installed in the roof
• Head tnangulation data may also be employed in vehicle operated by the handicapped By moving one's head in a prescribed manner the person can activate and/or control various devices Vehicle devices activated in this manner may include the various driving controls as well as turn signals, horn, cruise control, lights, and the like
• Vehicle devices activated in this manner may include the various driving controls as well as turn signals, horn, cruise control, lights, and the like
• the table below demonstrates eight distinguishable head motions in X and/or Y axes, which can be employed by a handicapped person to activate various devices in the vehicle
• a control device may utilize the capacitive sensor 5 inside or on a cover 14, so the sensing fields 13 extend outward from the control device 14
• the person could activate the control by moving his hand a certain distance into the field, which is detectable due to causing a -19- change in capacitive coupling between the electrodes of the sensor
• One application of this device could be to activate the horn switch 50 located on the steering wheel of a vehicle
• the basic form of the sensor is employed in vehicles with a solid roof structure, which allows greater freedom in sensor design and placement, e g , directly above the seats, and use of round electrodes which create hemispheric sensing fields sensitive to the occupant's head
• Fig 8 One configuration of the sensor, employing "L" shaped electrodes is depicted in Fig 8 In Fig 9 a vehicle installation is shown using opposing pairs of the sensors positioned in the vehicle roof The sensors of course will be covered by the vehicle headliner t ⁇ m (not shown) Various other arrangements of the electrodes may be employed, including multiple drive frequencies, as shown in Fig 10
• the electrodes are formed on one surface of a dielectric substrate 51, with a grounded area 24 surrounding the electrodes and throughout the opposite surface (not shown) of the dielectric substrate 51
• the grounded opposite side is connected to the grounded areas surrounding the electrodes, by plated through holes, edge folding, a crimped connector, staple or rivet, or other means (not shown)
• the power, ground, and input/output lines 23 are fed to electronic parts (not shown) installed adjacent to the electrodes 20,21 , either directly on the substrate 51 , on a separate circuit board 22 adhered to the substrate 51 , or on the opposite side of the substrate In the latter case, connection to the electrodes may be accomplished with plated through holes or other means (not shown)
• the algorithm to determine position may use voltage threshold values and apply lookup tables, other logical means, or employ geometric relationships
• the "L" shape capacitive sensor 26 can be installed at each corner of the sunroof, in a manner to provide -20- overlapping sensing fields beneath the sunroof edge and open area 25, in which an occupant's head is located.
• the electrodes may be positioned around the perimeter of the sunroof opening, and may be operated at various frequencies.
• An illustrative configuration is shown in Fig. 10, in which a set of drive electrodes 27 and receive electrodes 28 are operated at a first frequency, and a second set of drive electrodes 29 and receive electrodes 30 are operated at a second frequency.
• the sensing system thus described may be used to modify airbag deployment characteristics based on occupant head position, or for various other applications disclosed in applicant's issued and pending patent applications.
• the electronics or microprocessor supporting the L electrode capacitive sensors may maintain various reference values of sensor output.
• the reference function determines if the reference output value indicates a default closed position of the sunroof, or has changed in some magnitude to indicate any of the possible open sunroof positions. If the reference has changed, alternate lookup tables or modifications to head position algorithms are employed. This change in reference output may be rechecked each time the sunroof cover motor is activated, or may be continuously checked if the cover is manually operated.
• a reference sensor can be employed to detect moisture on the plastic or glass covering over the sunroof opening, as this is known to have an effect on capacitive sensor response. Change in the reference sensor output is used to adjust the lookup tables, or modify the algorithm which determines occupant head position.
• FIG. 15 An alternative arrangement of electrodes is depicted in Fig. 15.
• the L-electrodes which are driven by an oscillator signal surround each leg of a "+" shaped electrode which receives the signal above ground plane 200 and near electronic parts 206.
• the advantage of this arrangement is to achieve increased sensing range attributable to the greater X-Y span of the receive electrode 204. While the drive and receive functions can be reversed, the -21- design is simplified as shown because the four drive electrodes 202 can be connected by a circuit trace 208 positioned outside the end of each leg of the "+"
• Applicant's pending U S Patent Application Serial No 08/778,871 demonstrates a sensor array constructed of a flexible dielectric substrate with integrated die-cut cable, electronic parts adjacent to the electrodes, and grounded areas surrounding the electrodes connected to the opposite side ground plane either with or without penetrating the substrate
• Figs 11 (a)-(c) and 12 An adjacent electrode capacitive sensor constructed as shown in Figs 11 (a)-(c) and 12 will achieve substantially the same results as the above-claimed sensor construction
• the electronic parts 8 are installed either directly on the back side of the dielectric substrate 35, or on a "daughter" board 36 which is adhered to the back side Rather than a die-cut integrated cable, a standard connector 32 is employed to connect power, ground, and input/output (I/O) 36 which are provided by a conventional cable (not shown)
• the grounded area 24 surrounding the electrodes 34 is connected to the grounded backplane 31 with plated through holes 33
• an external ground connection can be employed as disclosed in the pending U S application

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Aviation & Aerospace Engineering (AREA)
• Transportation (AREA)
• Air Bags (AREA)
• Seats For Vehicles (AREA)
• Geophysics And Detection Of Objects (AREA)

Priority Applications (4)

Applications Claiming Priority (18)

Publications (1)

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Cited By (22)

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Citations (5)

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• 1997
  • 1997-04-23 WO PCT/US1997/006822 patent/WO1997039920A1/en not_active Application Discontinuation
  • 1997-04-23 AU AU27412/97A patent/AU2741297A/en not_active Abandoned
  • 1997-04-23 JP JP53831297A patent/JP4122417B2/ja not_active Expired - Fee Related
  • 1997-04-23 EP EP97921350A patent/EP0895500A4/en not_active Withdrawn
• 2006
  • 2006-11-22 JP JP2006315277A patent/JP2007045415A/ja active Pending

Patent Citations (5)

Non-Patent Citations (1)

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