DE102007029407B4 - Device for distinguishing between a rear-facing child seat and an adult occupant in a motor vehicle - Google Patents

Abstract

Device (1) for distinguishing at least between a rear-facing child seat and an adult occupant (16) in a motor vehicle, comprising
A light source (2) emitting a collimated light beam (5),
- A first means for periodically pivoting the light beam (5) by at least one predetermined deflection angle (6) in at least one spatial direction, whereby along a given by the at least one deflection angle trajectory (7) reflection points (12) on surfaces of at least temporarily in Beam path of the light beam bundles objects (16) are periodically illuminated,
- A second means for determining at least within a predetermined distance range (11) lying distances to the periodically illuminated reflection points (12), and
A third device for distinguishing between at least one adult occupant (16) and a rear-facing child seat on the basis of the distances to the periodically illuminated reflection points (12),
characterized,
that the light beam (5) is emitted with changing wavelength.

Description

The The invention relates to a device for distinguishing between arranged backwards Child seat and an adult occupant in a motor vehicle, according to the generic term of claim 1.

It are currently located so-called smart airbags in development, which is the risk of injury for in particular in forward directed child seats in a motor vehicle accommodated children to reduce in an accident. It is envisaged to trigger the Airbags in an accident depending on whether a with seat equipped with an airbag is occupied or free, respectively which type of occupancy is present, for example, whether with an adult or with a child seat.

by virtue of the short distance between the front seat airbag, typically the passenger seat airbag, and arranged backwards, also called so-called Rear Facing Child Seat, RFCS, designated reboard child seats, in which infants are facing backwards, contrary to the direction of travel for example, be accommodated in the passenger seat exists for a sitting in such a child seat child at a higher risk, through an airbag deployment seriously hurt. This can be the case in case of an accident heavy or a child accommodated in a reboard child seat even deadly Injuries result.

So far be used to automatically detect a seat occupancy or to distinguish between seat occupancy by an adult or by an object on walls Technologies such as weight sensors and sensor mats.

weight sensors determine the weight acting on a seat. A distinction between a person and an object is limited possible, especially the measured weight is adversely affected by the belt force.

With in the seats the sensor seats arranged in the form of a pressure-sensitive Sensors provided surface is tried by determining the size and possibly the Contour of the surface, on the pressure exercised is to distinguish between persons and objects. A Distinction between objects, such as a child seat, and people is doing so with great effort connected.

One substantial disadvantage of weight sensors and sensor mats Furthermore in that they are platform dependent for each Vehicle model or for Each vehicle seat must be made separately and calibrated.

By the EP 1 792 788 A1 a seat occupancy recognition device for a passenger compartment of a motor vehicle is known. An infrared laser beam is mechanically periodically pivoted and thereby scans an area that includes a vehicle seat with associated airbag. The reflected laser light is detected by means of a solid state imager, from which a digital signal processor creates a three-dimensional profile of the scanned area. The three-dimensional profile is used to detect and characterize an occupant or object occupying the seat, as well as to determine the distance or proximity of the occupant or object to an airbag.

By the DE 100 37 220 A1 are a method and a device for situation-specific control of the safety systems in a motor vehicle, in which the control of the safety systems depends on the seat occupancy and possibly of the sitting position. In order to achieve that the security is more precisely adapted to the situation, in particular when the security systems are triggered, it is provided that the seating position and / or the seat occupancy is scanned with the aid of a pulsed laser beam.

By DE 102 32 162 A1 a device for detecting a subject state is known which comprises an active distance measuring sensor ( 101 ) with several projectors ( 110 ) for independent extraction on measuring regions and with a photodetector ( 116 ) for detecting light reflected from a subject onto which the multiple projectors throw their light. A measurement parameter decision section ( 2 ) decides beforehand about a currently measured body parameter. In response to the parameter, a selection section ( 3 ) for the distance measuring sensors, a measuring region of the active distance measuring sensor and an additional distance measuring sensor ( 102 -04). A state decision section ( 4 ) decides a state of the subject based on the detection output of these sensors

By DE 100 28 703 A1 is a device ( 10 ) for detecting persons or objects for safety systems of vehicles. The device comprises a device ( 11 ) for capturing an image of the person or object and a processor ( 14 ) for processing the captured image. The device ( 11 ) for capturing an image comprises at least ei a laser beam ( 12 ), the laser light ( 13 ) deflecting prism body ( 15 ) and a laser light reflected from the person or object ( 13 ) receiving detector system ( 16 ). The prism body ( 15 ) is relative to the laser beam ( 12 ) arranged such that it is relative to the laser beam ( 12 ) performs a rotating and / or tumbling motion.

to Distinction between reboard child seats and adult occupants a motor vehicle is therefore a cost-effective, platform-independent automatic Device for distinguishing between a rear-facing child seat and an adult occupant needed.

A The object of the invention is therefore, a cost-effective device to disposal to provide, which is a reliable Distinction between an adult inmate and a backlit one Child seat allowed in a motor vehicle and which simple and be universally integrated into an interior of a motor vehicle can.

The Task is solved by a device for distinguishing between a backward arranged Child seat and an adult occupant in a motor vehicle according to the features of claim 1. Advantageous developments The invention will become apparent from the dependent claims and the following description.

The Device comprises a light source, for example in the form of a LED or a laser light source, which emits a collimated light beam. About that In addition, the device comprises a first device for preferably harmonic, periodic pivoting of the light beam of a starting position based on at least one predetermined Deflection angle in at least one spatial direction, so this at least one seat of the motor vehicle passes over, whereby along a predetermined by the at least one deflection angle trajectory lying reflection points on surfaces of at least temporarily located in the beam path of the light beam, the light beam, for example diffuse reflecting objects in periodically recurring cycles be illuminated. Furthermore has the device over a second means for determining at least within one predeterminable distance range lying distances to those in periodically recurring Cycles illuminated reflection points on that of the collimated Pass through light beam Trajectory, as well as a third device for distinguishing at least between an adult occupant and a rear-facing child seat on the basis of preferably during at least one cycle determined intervals to those in periodically recurring Cycles illuminated reflection points on the trajectory.

According to the invention Light beam modulated, so emitted with changing wavelength of the light source. In conjunction with a suitable, appropriate filtering of the Light can the device of the invention independent of operated reliably to the prevailing temperature and light conditions become. For this purpose, one of the second device with the changing wavelength of the emitted light beam corresponding filtering of the reflected from the reflection points Beam of light feasible. A Such corresponding filtering can be achieved, for example, by lock-in, by a phase locked loop (PLL), or according to the synchronous rectifier principle respectively. Compared to the The state of the art is thereby the field of application of the device according to the invention extended from direct sunlight to complete darkness.

A distinction between a reboard child seat and an adult occupant or the determination of at least within a predefinable distance range distances to the illuminated in periodically recurring cycles reflection points on the trajectory is carried out in the inventive device preferably by triangulation. The collimated light beam, for example an infrared laser beam, is thereby periodically deflected or pivoted about a deflection angle with the first device comprising a mechanical element, such as a rotating or pivoting mirror or a rotating or pivoting prism or a rotating or pivoting lens. The deflected light beam illuminates a curve, for example, from the perspective of the light source in the form of a straight line or an ellipse, on a located in the beam path of the light beam object, for example, on a seat occupant occupant. The illumination takes place in such a way that the individual reflection points which jointly form the curve are periodically illuminated one after the other. The second device, for example in the form of a position-resolving infrared sensor, such as a two-dimensional PSD element derived from the Photo-Sensitive Device or Position Sensing Detector, receives the light beam diffusely reflected from the reflection points. The distance measurement is carried out by triangulation. The third device makes a distinction at least between an adult occupant and a rear-facing child seat based on the preferential For example, during at least one cycle during which all the reflection points along the curve have been illuminated at least once, there are certain distances to the reflection points. In an empty seat or a child seat, there is only a narrow area formed by the back of a seat for which the device is provided, in which a short distance is measured. If the seat is occupied by an adult occupant, the area in which a small distance is measured is larger. This area is formed by the back and torso of the adult occupant. In addition, by a large deflection angle and the backrest of the reboard child seat in the form of a second, narrow area in which a short distance is measured, detected and used to distinguish.

By Using a collimated light beam, which by means of a suitable Device is pivoted in at least one spatial direction, instead for example, a fan-shaped emitted Line lasers, the complexity the typically a laser optics forming optical elements and the for needed the second device optical sensors significantly reduced. Besides that, so in comparison for example, to a laser fan a substantially low re intensity of preferably in the form be used by laser light emitted light, as to each Time only a single point of reflection is illuminated, and not a complete one Line or a complete one Area. Furthermore can be pivoted by the pivotable as scanner principle of the light beam by means of the first device with much simpler means a larger angle range Be covered as required for generating a laser fan refractive Look.

Important It should be emphasized that the term reflection point is by no means a specially prepared Point on the surface of an object. Rather, every point on the surface of one suffices Object as a reflection point when it is periodically illuminated by the light beam and is able to diffuse the light beam, for example to reflect.

Basically It is conceivable that a detection of a vacant seat by a weight sensor or the like, as well It is conceivable that the device according to the invention is activated only then is displayed, when indicated by the weight sensor, a seat occupancy is present. A detection of a vacant seat is also as described above with the device according to the invention possible.

advantages The invention also provides, inter alia, by the usable, simple sensor technology and the possibility of a platform-independent integration For example, in the headliner or laterally next to a seat, for example in the B-pillar. As a result, development and manufacturing costs are compared lowered to the prior art, creating a device which is also cheaper in motor vehicles can be used to there the sometimes serious consequences of a airbag deployment for a avert a toddler housed in a reboard child seat.

With only small modifications, the device of the invention for all seating adapted in a motor vehicle and there for other applications, as for one Distinction between seat occupancy by an adult or a reboard child seat.

Further Advantages of the invention result from the fact that the distinction at least between an adult occupant and a backward one Child seat by measuring distances used measuring principle contactless is, which makes the device much lower loads and thus wear and tear both by the occupants themselves, as well as by accident situations, where no airbag deployment takes place, for example, as weight sensors or Sensor mats. The simple measuring principle also allows one much cheaper Manufacture, as the known weight sensors and sensor mats.

A advantageous development of the device according to the invention provides that by means of the third device a distance profile from the measured distances is configurable to the points illuminated in periodic cycles, by means of a distinction between at least one adult Inmates and one arranged backwards Child seat feasible is.

The For this purpose, the third device preferably consists of one with the second device associated evaluation unit, which from the Output signals of the second device creates a distance profile, on the basis of example by comparison with predetermined distance profiles at least one adult passenger and a rear-facing child seat are distinguishable. additionally is conceivable, based on such a distance profile also a blank Seat to recognize.

The second device preferably consists of a receiver which is one of a plurality of light beams reflected by the reflection points Scope sensitive sensors existing sensor field, each of which detects its own, limited angular range within an opening or solid angle covering the trajectory formed by the light beam periodically illuminated points, and at least within a predetermined distance range and within observed by him Angle range lying reflection point of an object generates an output signal analogous to the distance of the reflection point. Each sensor observes its own angular range of the opening or solid angle covering the trajectory formed by the points periodically illuminated by the light beam. Each sensor produces an output signal which is analogous to the distance of the reflection point when the light beam reflected by a reflection point located within the predetermined distance range and in the direction of the angular range observed by it. The third device designed as an evaluation unit connected to the receiver can create a distance profile from the distances determined by the individual sensors of the sensor field. An empty seat, a seat occupied by an adult occupant, and a seat occupied by a rearward-facing child seat each produce different spacing profiles. As a result, the device according to the invention can distinguish between a vacant seat, an adult occupant and a rear-facing child seat.

The Sensors of the sensor field can for example, PSD sensors and / or CCD sensors and / or CMOS sensors. Such sensors are known and available in the market and thereby allow a cost-effective production of the device according to the invention. For example, laser triangulation sensors are known which have a Laser light source and a photodiode with a strip-like drawn surface sensitive to light trained recipient include.

With lets them the distance to one of the laser light source punctiform illuminated Place on the surface measure an object. The location is called a reflection point. The location of a point of impact of the reflected and reflected at the reflection point diffuse back scattered laser light along the striped light-sensitive area changed depending on the Distance of the reflection point to the laser triangulation sensor. Depending on Location of the point of impact changed the relationship between certain currents in the laser triangulation sensor. The ratio of these electrical currents results an analog output signal which thus provides a measure of the distance of the reflection point from the laser triangulation sensor. The receiver of the laser triangulation sensor described above is a PSD sensor derived from Photo-Sensitive Device or Position Sensing Detector, known. The advantage of this type of receiver is an easy to use one realizing measuring electronics and its high sampling rate of up to 10 MHz. An alternative recipient with similar operating principle provides a CCD sensor, derived from Charge Coupled Device. CMOS sensors have a much higher dynamic range and thus have a much higher brightness range, within which they can be used. For example, CMOS sensors can see much better in the dark than other sensors.

Of the specifiable distance range is in an advantageous embodiment of the invention preferably 0 to 60 cm. This distance range is especially at a lateral Arrangement of the device according to the invention advantageous because the center of the seat on which a befindliches there Object, especially a person or a child seat its largest dimensions not further away, for example, from the B-pillar is. About that In addition, the distance range also covers the case of being an adult or an article covers the device according to the invention.

Of the specifiable distance range is in another advantageous embodiment of the invention preferably 10 to 120 cm. This distance range is in particular at a Arrangement of the device according to the invention above a seat, in particular in the headliner advantageous, because the distance of an object, especially a person or a Child seat from the headliner lies within this order of magnitude.

The The first device preferably comprises a light beam periodically pivoting, first mechanical element, such as a rotating or pivotable mirror or a rotating or a pivotable Prism or a rotating or a pivoting lens.

Basically also conceivable that the first device transparent, for example, for the light beam, So for comprising the frequency of the electromagnetic waves of the light beam transmissive body, its refractive properties by applying a mechanical or electrical voltage can be changed continuously.

The second device may also be a light beam reflected from the reflection points in synchronism with the pivoting of the emitted light beam through the first device by the deflection angle to a Sensor or a sensor field deflecting, second mechanical element. This additionally simplifies the required optics for the second device, while covering a very large scannable angle range. In addition, the deflection angle can be detected from, for example, a rotation angle of the first or second mechanical element and used for distance determination by triangulation. By the light beam reflected at a reflection point in synchronism with the pivoting of the emitted light beam by the first device by the deflection angle to a sensor or sensor field deflecting second mechanical element, the receiver can be made much simpler. Thus, for example, no time-consuming, cost-intensive optics are required on the receiver side which covers the entire deflection angle and images, for example, onto a sensor field. In addition, the sensors required for a distance measurement by triangulation simplify. Thus, when using a second mechanical element designed, for example, as a rotating mirror, it is sufficient to use a simple PSD element instead of a sensor field consisting of several PSD elements in order to determine the position and thus the distance to a reflection point. Moreover, the second mirror does not require a complex optical system that covers the entire deflection angle of up to 100 °. Another advantage of using a second mechanical element is that the evaluation unit can be made much simpler, for example, because of the simplified receiver with a smaller memory compared to that required for an evaluation of a sensor field.

Preferably For example, the first and second mechanical elements are mechanically interconnected connected. This is a particularly simple coupling between the spatial directions of the emitted and pivoted and the reflected and received light beam in conjunction with a small in size sensor or Sensor field with easily executable Optics achieved.

The Light source preferably emits an infrared light beam. Infrared light is outside of the human eye detectable wavelength range and directs the driver of the motor vehicle from the traffic.

A Particularly advantageous embodiment of the invention provides that the device, or at least the light source and the first device of Device, the side of a seat in the interior of a motor vehicle is arranged so that the light beam in a direction across sent to the direction of travel and in a substantially horizontal Level is pivoted transversely to the direction of travel. An arrangement sideways a seat allows a particularly reliable distinction between adult inmate, backward-facing Child seat and empty seat, as seen from this direction of observation gives a particularly easy interpretable distance profile. Preferably is the device according to the invention doing it in a window pillar, arranged, for example, the B-pillar. An arrangement in the A, B, C or D pillar allows a largely platform-independent configuration of the device according to the invention. At least the light source and the first device are the Device at height a backrest or a headrest the seat arranged. An arrangement above or next to a seat allows in particular a platform-independent and thus cost-effective design the device according to the invention.

A another, particularly advantageous embodiment of the invention sees before that the device, or at least the light source and the first device of the device, above a seat, for example in the headliner or in a window column connecting cross strut, is arranged in the interior of a motor vehicle, so that the light beam in a direction transmitted transversely to the direction of travel and preferably is pivoted in a substantially vertical plane. An arrangement Above a seat allows for a simple integration in a motor vehicle and on the other hand a reliable distinction between adult inmate, backward-facing Child seat and free seat, as seen from this direction of observation a likewise easily interpretable distance profile results. Preferably, the device according to the invention is in the headliner arranged, for example in the range of the rearview mirror or in the area the interior lighting or in the roof console with the actuators for example Sunroof, interior lighting, on-board computer and the like. An arrangement in the headliner allows ei ne platform independent design the device according to the invention.

Either an arrangement of the device according to the invention side of a seat, as well as above a seat allows one reliable Distinction between adult occupant, rear-facing child seat and free seat for all seat and backrest adjustments.

Of the Deflection angle of the light beam is preferably about 90 °. hereby can be a particularly wide adjustment of a seat of only one Place from being observed with sufficient accuracy.

The Invention will be explained below with reference to the drawings. there demonstrate:

1 a schematic representation of a device according to the invention,

2 a detailed view of the receiver and the evaluation of 1 in an enlarged view,

3 a schematic representation of an integration of a device according to the invention in the B-pillar of a motor vehicle,

4 1 is a schematic representation of a first embodiment of a laser light source sensor unit comprising a light source, a first device and a second device of a device according to the invention,

5 a schematic representation of a rotating element of in 4 illustrated laser light source sensor unit,

6 a schematic representation of a second embodiment of a laser light source sensor unit,

7 a schematic representation of a third embodiment of a laser light source sensor unit in a first operating state,

8th a schematic representation of a rotating element of in 7 illustrated laser light source sensor unit in a first operating position,

9 a schematic representation of the laser light source sensor unit 7 in a second operating state,

10 a schematic representation of a rotating element of in 7 illustrated laser light source sensor unit in a second operating position,

11 a schematic representation of a fourth embodiment of a laser light source sensor unit,

12 a schematic representation of a fifth embodiment of a laser light source sensor unit in a first operating state,

13 a schematic representation of the laser light source sensor unit 12 in a second operating state.

An in 1 illustrated inventive device 1 to distinguish between a rear-facing child seat and an adult occupant in a motor vehicle substantially comprises a light source in the form of an infrared laser light source 2 , a first device in the form of a mechanically pivotable mirror 20 , a second device in the form of a receiver 3 and a third device in the form of a with the receiver 3 connected evaluation unit 4 , The infrared laser light source 2 sends a collimated light beam in the form of an infrared laser beam 5 out. The mechanically pivotable mirror 20 pivots the infrared laser beam 5 harmonically and periodically starting from a starting position by a predefinable deflection angle 6 in a spatial direction. This will be along a by the deflection angle 6 predetermined trajectory 7 lying reflection points 12 on a surface of a in the beam path of the light beam 5 located, the infrared laser beam 5 diffusely reflecting object 13 illuminated in periodically recurring cycles.

The recipient 3 serves the determination of within a predefinable distance range 11 lying distances to the illuminated in periodically recurring cycles reflection points 12 on the from the infrared laser beam 5 traversed trajectory 7 , The recipient 3 For this purpose, one comprises a plurality of the infrared laser beam reflected by the reflection points 5 sensitive sensors 8th existing sensor field 9 , Every sensor 8th observes its own, limited angle range 10 within one of the by the infrared laser beam 5 periodically illuminated reflection points 12 formed trajectory 7 covering, by the deflection angle 6 formed opening or solid angle ( 2 ). The sensors 8th are able to do so within the angular range they are watching 10 Distances within the predefined distance range 11 capture. The sensors 8th generate at one within the distance range 11 and within of the respective sensor 8th observed angle range 10 lying, the infrared laser beam 5 diffuse backscattering reflection point 12 of the object 13 , which can be both a person or an object, the distance of the reflection point 12 analogue output signal.

The one with the receiver 3 connected evaluation unit 4 created from the output signals of the individual sensors 8th of the sensor field 9 and with knowledge of the respective sensors 8th detected angle ranges 10 a distance profile by which a blank seat, an adult occupant and a rear-facing child seat is distinguishable.

It is important to emphasize that the representation in 1 a simplistic, schematic Representation of the measuring principle with strongly distorted proportions shows. Thus, in a technical implementation of the device according to the invention 1 for example, the recipient 3 , the laser light source 2 and the mechanically pivotable mirror 20 in the immediate vicinity, for example laterally next to a seat in a motor vehicle directly above one another, as in 3 shown in plan view, but not on top of each other, are arranged in a single housing, so that those of the infrared laser beam 5 periodically illuminated reflection points 12 formed trajectory 7 covering, by the deflection angle 6 formed opening or solid angle and from the individual angular ranges 10 composing, from the sensors 8th of the sensor field 9 Recipient 3 cover observed area. Likewise, an optic may be provided which the beam path of the at different reflection points 12 at the object 13 reflected infrared laser beam 5 depending on which of one of the sensors 8th observed angle range 10 the respective reflection point 12 lies on the respective sensor 8th directs. The optics can be part of the receiver 3 be.

Such an appearance can, as in the 4 to 13 also shown as one of the reflection points 12 reflected infrared laser beam 5 synchronous with the pivoting of the emitted infrared laser beam 5 through the mechanically pivotable mirror 20 around the deflection angle 6 on a sensor 8th or a sensor field 9 Recipient 3 deflecting, second mechanical element in the form of a second pivotable mirror 22 include. This additionally simplifies the required optics for the receiver 3 , while covering a very large scannable, from the individual angle ranges 10 composing deflection angle. In addition, the instantaneous deflection angle may correspond to a certain angular range 10 , For example, based on a rotation angle of the first mechanically pivotable mirror 20 and / or the second mechanically pivotable mirror 22 be captured and used for distance determination by triangulation. Thus, for example, the the respective angle range 10 indicating rotation angle of the mirror 20 . 22 recorded and the evaluation unit 4 be provided for creating the distance profile.

The first and the second mechanical element in the form of the first mechanically pivotable mirror 20 and the second mechanically pivotable mirror 22 are like in the 4 to 13 represented, mechanically interconnected. In this way, a particularly simple coupling between the spatial directions of the emitted and pivoted and the reflected and received infrared laser beam 5 in conjunction with a small in size sensor 8th or sensor field 9 achieved with easy executable optics. The first mechanically pivotable mirror, the second mechanically pivotable mirror and the mechanical coupling each form a rotating element 25 ' . 25 '' . 25 ''' . 25 '''' . 25 ''''' ,

At one in the 4 and 5 shown first embodiment of a laser light source sensor unit 33 ' is that of the infrared laser light source 2 ' sent out and by means of an optic 23 ' collimated infrared laser beam 5 ' on a first rotating mirror 20 ' directed. By the rotation of the mirror 20 ' becomes the infrared laser beam 5 ' periodically pivoted by a deflection angle of up to 90 ° or, if necessary, more periodically. The infrared laser beam 5 ' is from a reflection point 12 ' on an object 13 ' reflects and hits a second rotating mirror 22 ' through an optic 24 ' on a sensor 8th' , The first mechanically pivotable mirror 20 ' and the second mechanically pivotable mirror 22 ' are mechanically coupled with each other. The first mechanically pivotable mirror 20 ' and the second mechanically pivotable mirror 22 ' as well as the mechanical coupling form the rotating element 25 ' , To allow tolerances is the field of view of the sensor 8th' larger at any moment than the one by the infrared laser beam 5 ' illuminated reflection point 12 ' , The essentially by the rotating second mirror 22 ' and the sensor 8th' formed receiver is similar to an infinite-finite imaging optics. In an in 5 shown, the two mirrors 20 ' and 22 ' containing rotating element 25 ' is a magnet 26 ' arranged. A coil 27 ' surrounds a in 4 illustrated cylindrical housing 28 ' , One in the case 28 ' arranged photodiode 29 ' is used for self-diagnosis and for the rotation angle of the rotating element 25 ' capture.

In the 6 illustrated second embodiment of a laser light source sensor unit 33 '' agrees with the functional principle with the in the 4 and 5 illustrated embodiment, which is why dispense with a separate description of the matching features. To distinguish the matching or equivalent features with reference numerals with the same reference numbers, but provided with different indices. An essential difference of 6 across from 4 is that the emitted infrared laser beam 5 '' over a mirror 30 '' on the rotating element 25 '' is deflected, and that the received, reflected infrared laser beam 5 '' from the rotating element 25 '' out over a mirror 31 '' on the sensor 8th'' is diverted. This simplifies assembly and manufacture. Now all parts of the infrared laser light source 2 '' , the optics 23 '' , the photodiode 29 '' , of cylindrical housing 28 '' including rotating element contained therein 25 '' , the optics 24 '' and the sensor 8th'' , which together form the light source, the first device and the second device of the device according to the invention, on a circuit board 32 '' be soldered or stapled.

The in the 7 to 10 illustrated third embodiment of a laser light source sensor unit 33 ''' agrees with the functional principle with the in 6 illustrated embodiment, which is why dispense with a separate description of the matching features. To distinguish the matching or equivalent features with reference numerals with the same reference numbers, but provided with different indices. An essential difference of the laser light source sensor unit 33 ''' of the 7 to 10 across from 6 is that the mirrors 20 ''' and 22 ''' of the rotating element 25 ''' each with a hole forming a reference point 34 ''' are provided, through which the infrared laser light beam 5 ''' at a certain angle of rotation of the rotating element 25 ''' Straight and without detours from the infrared laser light source 2 ''' to the sensor 8th''' can get. This allows the function of the photodiode by the sensor 8th''' be taken over, the now per revolution of the rotating element 25 ''' through the direct impinging infrared laser light beam 5 ''' generates a pulse. The infrared laser light beam 5 ''' does not hit the middle of the mirror 20 ''' but offset.

The hole 34 ''' or another, suitable device with which the emitted light beam 5 ''' at least once per revolution of the rotating element 25 ''' directly on the sensor 8th''' In addition, it enables a variety of diagnostic functions. For example, it can be diagnosed whether the light source, here preferably a laser, radiates with a constant intensity. It can also be determined if the rotating element 25 ''' turns, or if it is stuck. In addition, the orientation of the rotating element can be diagnosed.

At the in 11 illustrated fourth embodiment of a laser light source sensor unit 33 '''' has the rotie-generating element 25 '''' not like in 10 in each case only one respective reflective surface deflecting the light beam on each end side, but now each having four mirror-symmetrically arranged surfaces arranged in pyramid shape. By an offset to the axis of rotation frontally on the rotating element 25 '''' Directional light beams are the lying on the trajectory reflection points in a full revolution of the rotating element 25 '''' illuminated four times. In addition, a higher rotational symmetry and thus a better concentricity of the rotating element 25 '''' reached.

In the in the 12 and 13 illustrated fifth embodiment of a laser light source sensor unit 33 ''''' are each end side two saddle roof shaped arranged to each other, mirrored surfaces provided. By an offset to the axis of rotation frontally on the rotating element 25 Directional light beams are the lying on the trajectory reflection points in a full revolution of the rotating element 25 illuminated twice. Also, opposite to the rotating element 25 ''' in 10 a higher rotational symmetry and thus a better concentricity of the rotating element 25 reached.

Also the rotating elements 25 '''' and 25 ''''' in the 11 . 12 and 13 can with a reference point in the form of a light beam emitted by the light source, for example, directly to the receiver transmitting hole for generating a reference signal per revolution of the rotating element 25 '''' respectively. 25 ''''' be provided. This also allows the implementation of the other top for the rotating element 25 ''' described diagnostic functions.

An integration of a device according to the invention 1 into the B-pillar 14 of a motor vehicle is in 3 shown. light source 2 , mechanically pivotable mirror 20 and receiver 3 are housed in a common housing in close proximity to each other. The evaluation unit 4 can be arranged at any point in the vehicle, for example, in the same housing as the light source 2 , the mechanically pivoting mirror 20 and the receiver 3 ,

The device 1 sends transversely to the longitudinal axis 19 of the motor vehicle a periodic over seat back 15 and seat 17 within a deflection angle 6 90 ° tilted infrared laser beam 5 out. The infrared laser beam 5 illuminates objects 13 , which are in the beam path, along a trajectory 7 , This trajectory 7 consists of the harmonic, periodic pivoting of the infrared laser beam 5 successively illuminated reflection points 12 ( 1 ) together.

From a reflection point 12 on an object 13 within a distance range suitably selected according to the installation situation 11 reflected light becomes diffuse to the device 1 backscattered. The distance range 11 here is preferably 0 to 60 cm. In the 2 illustrated sensors 8th of the sensor field 9 Recipient 3 each observe their own, limited angle range 10 within one of the by the infrared laser beam 5 periodically lit reflexi onspunkte 12 formed trajectory 7 covering, by the deflection angle 6 formed opening or solid angle. Meets the infrared laser beam 5 when driving off the trajectory 7 within the distance range 11 on an object 13 , such as on a seat back 15 and / or an adult inmate 16 of the motor vehicle, so watch the individual sensors 8th not the entire trajectory 7 but only within the respective angular ranges 10 lying reflection points 12 , Meets the infrared laser beam 5 to one of the reflection points 12 , so this radiates a part of the device 1 emitted infrared laser beam 5 diffuse back, whereby by means of the corresponding angular ranges 10 observing sensors 8th of the sensor field 9 Recipient 3 the distances to the individual reflection points 12 can be determined. The evaluation unit 4 the device 1 creates a distance profile from the measured distances, on the basis of this between an empty seat 18 an adult inmate 16 and a rear-facing child seat can be distinguished. The distinction is made by means of a suitable algorithm, for example by integration of the area under a curve formed by the individual distance values, or by a comparison with reference profiles or the like. The information about the type of occupancy of a seat 18 can now be used or made available to decide on an airbag deployment.

Claims (15)

Contraption ( 1 ) for distinguishing at least between a rear-facing child seat and an adult occupant ( 16 ) in a motor vehicle, comprising - a collimated light beam ( 5 ) emitting light source ( 2 ), - a first means for periodically pivoting the light beam ( 5 ) by at least one predetermined deflection angle ( 6 ) in at least one spatial direction, whereby along a predetermined by the at least one deflection angle trajectory ( 7 ) lying reflection points ( 12 ) on surfaces of at least temporarily located in the beam path of the light beam objects ( 16 ) are periodically illuminable, - a second device for determining at least within a predefinable distance range ( 11 ) to the periodically illuminated reflection points ( 12 ), and - a third device for distinguishing between at least one adult occupant ( 16 ) and a rear-facing child seat based on the distances to the periodically illuminated reflection points ( 12 ), characterized in that the light beam ( 5 ) is emitted with changing wavelength. Device according to claim 1, characterized in that that of the second device one with the changing wavelength of the emitted light beam corresponding filtering of the reflected from the reflection points Light beam feasible is. Device according to claim 1 or 2, characterized in that a distance profile from the measured distances to the points illuminated in periodic cycles can be produced by means of the third device, on the basis of which a distinction is made between at least one adult occupant ( 16 ) and a rear-facing child seat is feasible. Device according to claim 1, 2 or 3, characterized in that the second device consists of a receiver ( 3 ), which consists of several sensors ( 8th ) existing sensor field ( 9 ), each of which has its own limited angular range ( 10 ) within a trajectory ( 7 ) covering opening or solid angle, and at least within a predefinable distance range ( 11 ) and within the angular range observed by it ( 10 ) lying reflection point ( 12 ) one the distance of the reflection point ( 12 ) generates analog output signal. Device according to claim 4, characterized in that the sensors ( 8th ) of the sensor field ( 9 ) PSD sensors and / or CCD sensors and / or CMOS sensors are. Device according to one of the preceding claims, characterized in that the predefinable distance range ( 11 ) Is 0 to 60 cm. Device according to one of claims 1 to 5, characterized in that the predetermined distance range ( 11 ) Is 10 to 120 cm. Device according to one of the preceding claims, characterized characterized in that the first device is a periodically pivoting the light beam, comprises first mechanical element. Apparatus according to claim 8, characterized in that the second means a reflected from the reflection points Light beam in synchronization with the pivoting of the emitted light beam through the first device around the deflection angle on a sensor or a sensor field deflecting, second mechanical element comprises. Apparatus according to claim 9, characterized in that the first and the second mechanical element mechanically connected to each other are. Device according to one of the preceding claims, characterized in that the light source ( 2 ) an infrared light beam ( 5 ). Device according to one of the preceding claims, characterized characterized in that at least the light source and the first device the device above at least one seat of a motor vehicle are arranged. Device according to one of claims 1 to 11, characterized that at least the light source and the first device of the device laterally arranged next to at least one seat of a motor vehicle are. Device according to claim 13, characterized in that that at least the light source and the first device of the device at height a backrest or a headrest the seat are arranged. Device according to one of the preceding claims, characterized in that the deflection angle ( 6 ) of the light beam ( 5 ) is about 90 °.