Abstract:
An obstacle detection system for vehicular environments including a monitoring sensor system and a mounting system is disclosed. An installer can make aiming adjustments, in the factory or field, to account for tolerance stack-up. The system includes a housing for mounting the monitoring sensor system to minimize cross-talk and interference between transmitter and receiver sections, to limit sensor system movement, and to enable gross and fine aiming adjustments. In one embodiment, a circuit board is disposed within a cradle assembly which, in turn, is mounted in or integral to the housing to position the obstacle detection sensor as necessary. The cradle in one embodiment is an enclosure for the circuit board. The sensor housing is mounted to the interior vehicle trim, door panel, and/or door sheet metal and ensures consistent mounting regardless of interior trim or factory installation variations. Integral adjustment mechanisms are incorporated for adjusting the orientation of the sensor system. The circuit board may be comprised of plural subsections interconnected by flexible circuit board, enabling accurate alignment of each subsection with respect to the environment to be monitored.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 60/257,081, filed Dec. 20, 2000, which is incorporated herein by reference. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to an electronic sensor system for monitoring a window, door or other opening associated with a vehicle or vehicle interior, and in particular a system for mounting, aiming, and/or packaging such a sensor system.  
           [0003]    In recent years, electronic sensors have not been utilized for obstacle or intrusion detection in vehicle window systems because of complexity and mounting limitations. Typically, obstacle detection has been based on limit switches, window motor characteristics, or ultrasonic monitoring signals that do not have precise mounting or alignment requirements. Small variations in detection system mounting do not significantly effect the performance of these sensor systems. The variations in trim components and installer techniques obviates the use of potentially more sensitive and thus accurate monitoring systems which are subject to performance degradation as a result of misalignment with respect to an ideal mounting configuration.  
           [0004]    So-called tolerance stack-up results due to the variability in the physical relationship between a lens to emitters or detectors of an obstacle detection system, emitters or detectors to a circuit board on which they are mounted, the circuit board to the respective housing, the housing to vehicle trim and/or the respective door panel, and vehicle trim and/or the door panel to the door sheet metal. Variations from vehicle to vehicle, door to door, in system installation techniques within the vehicle factory, and in system installation techniques by after-market installers can all add to the tolerance stack-up problem.  
         BRIEF SUMMARY OF THE INVENTION  
         [0005]    The present invention provides an obstacle detection system which includes a monitoring sensor system and a mounting system. In a first embodiment, the obstacle detection system is adapted for use in a vehicular setting. The mounting system presently disclosed allows an installer to make aiming adjustments, in the factory or field, to account for the tolerance stack-up problems described above. The system includes a housing for mounting the monitoring sensor system to minimize cross-talk and interference between the transmitter and receiver sections, to limit sensor system movement based on vehicle component and factory installation variations, and to enable gross and fine aiming to accommodate field programmability.  
           [0006]    In a preferred embodiment of the invention, a circuit board is disposed within a cradle assembly which, in turn, is mounted in or integral to the housing to position the obstacle detection sensor in proximity with the target structure or region of the vehicle. The cradle in one embodiment is an enclosure for the circuit board, fabricated from a resilient material such as plastic. Importantly, the cradle does not obstruct or interfere with the operation of the transmitter or receiver associated with the sensor disposed on the circuit board. The cradle may facilitate sensor removal and replacement without requiring the removal of the housing. Thus, once the housing is properly aligned relative to the vehicle trim, maintenance can be performed on the sensor without effecting such alignment. The sensor housing is mounted to the interior vehicle trim, door panel, and/or door sheet metal and ensures consistent mounting regardless of interior trim or factory installation variations. In addition, integral adjustment mechanisms are incorporated in further embodiments to provide the ability to make adjustments in either an initial installation environment or after the vehicle is fielded. In yet another embodiment, the circuit board is comprised of plural subsections interconnected by flexible circuit board, enabling accurate alignment of each subsection with respect to the environment to be monitored. Thus, accurate installation is realized through features which locate the housing relative to the vehicle sheet metal or some other consistent reference surface, through adjustment tools associated with the housing which it is installed, or both. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0007]    These and other objects of the presently disclosed invention will be more fully understood by reference to the following drawings, of which:  
         [0008]    [0008]FIG. 1 is a diagrammatic view of components of an obstacle detection system according to the presently disclosed invention;  
         [0009]    [0009]FIG. 2 is a perspective exterior view of a first embodiment of an obstacle detection system housing according to the presently disclosed invention;  
         [0010]    [0010]FIG. 3 is a perspective interior view of the housing of FIG. 2; and  
         [0011]    [0011]FIG. 4 illustrates the placement of the obstacle detection system of the presently disclosed invention in association with the sheet metal of a vehicle door;  
         [0012]    [0012]FIG. 5 is a diagrammatic view of components of a further embodiment of the obstacle detection system of FIG. 1;  
         [0013]    [0013]FIG. 6 is a plan view of a circuit board for use in the obstacle detection system embodiment of FIG. 5;  
         [0014]    [0014]FIG. 7 is a perspective view of a lens module for use in the obstacle detection system embodiment of FIG. 5;  
         [0015]    [0015]FIG. 8 is a cross-sectional view of a fastener for the presently disclosed obstacle detection system;  
         [0016]    [0016]FIG. 9 is a plan view of an aperture for receiving the fastener of FIG. 8;  
         [0017]    [0017]FIG. 10 is an elevation view of a first alignment mechanism for use with the presently disclosed obstacle detection system; and  
         [0018]    [0018]FIG. 11 is an elevation view of a second alignment mechanism for use with the presently disclosed obstacle detection system. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    The presently disclosed invention enables the accurate installation of an obstacle detection system, such as for use in conjunction with a vehicle window, as well as the alignment of components of the system for optimal performance. An obstacle detection system according to the presently disclosed invention is comprised of the active circuitry responsible for detecting an obstacle and a mounting subsystem which enables accurate alignment of portions of the active circuitry.  
         [0020]    [0020]FIG. 1 provides a schematic illustration of a circuit board employed as part of the active circuitry. The individual active components and their function may be as described in U.S. Pat. No. 5,955,854, owned by the same assignee as the present application and incorporated herein by reference. With reference to FIG. 1, an energy field may be generated proximate a window opening, in which a power window operates, through the use of infrared (IR) light emitting diodes (LEDs)  12 . Energy reflected off one or more objects or surfaces in the path of the emitted energy is detected by co-located IR detectors  14 . A processor  16 , such as a specially-programmed microprocessor with associated memory, is used to control the operation of the emitters  12  and to analyze the output of the detectors  14 . However, it should be understood that other components may be substituted to the extent that such components work in concert with the inventive concepts disclosed and claimed herein.  
         [0021]    One or more circuit boards  20  are employed for mounting the circuitry. Because the window opening to be monitored is typically non-planar, and as a result of the varying active fields of the emitters  12  and detectors  14 , it is often necessary to dispose the active fields of the emitters  12  and detectors  14  in different planes. In the embodiment illustrated in FIG. 1, a circuit board  20  used to mount the active detector system components is comprised of two rigid circuit board portions  22 ,  24  interconnected by a flexible circuit board portion  26 . Signal pathways  30  between the processor  16  and the emitters  12  and detectors  14  are shown schematically. Depending upon the particular physical environment to be monitored, two or more circuit board portions may be interconnected at a variety of locations by flexible portions. The embodiment of FIG. 1 is merely one example.  
         [0022]    The portion of the presently disclosed obstacle detection system used to mount the system in association with the vehicle typically includes a housing  40 , such as in the exemplary embodiment of FIG. 2. Preferably, such a housing  40  is fabricated of a material which is complimentary to that of the vehicle trim. Considerations including environment temperature fluctuation, ultraviolet exposure, and physical jarring must be borne in mind in selecting appropriate materials for the housing  40 .  
         [0023]    Disposed on a surface of the housing are one or more lenses  42 . These lenses may be transparent to the active wavelengths employed by the emitters  12  and detectors  14 , or may be selected from materials or may be provided with a physical configuration which imparts a desired beam shaping or focusing effect on the transmitted and reflected energies. The illustrated housing embodiment of FIG. 2 is particularly adapted for installation in a lower front corner of a vehicle window, as illustrated in FIG. 4. Such a housing may be used to accommodate other circuitry in addition to that of an obstacle detection system.  
         [0024]    [0024]FIG. 3 provides a perspective illustration of the reverse side of the housing  40  shown in FIG. 2. In this embodiment, two discrete circuit boards  44 ,  46  are employed rather than the single, multi-segmented circuit board  20  of FIG. 1. Optical isolation between transmit and receiver elements is provided by an opaque or non-transmissive barrier integral to the housing. The placement of the housing  40  in relation to a vehicle door assembly is shown in FIG. 4.  
         [0025]    [0025]FIG. 5, similar to FIG. 3, illustrates the reverse side of a housing  60  for use in mounting obstacle detection circuitry proximate an aperture to be monitored. In this case, however, the circuit boards  44 ,  46  have been replaced with a circuit board receptacle  62  or “cradle.” The cradle  62 , which in a preferred embodiment is formed of extruded plastic, is adapted for receiving a specifically configured circuit board or circuit boards and for enabling the accurate placement of the circuit board(s) in relation to the housing  60 . One or more stanchions  64  are provided in the illustrated embodiment in order to accurately locate one or more circuit boards within the cradle  62 . The cradle  62  may also be provided with one or more mounting flanges  58  for securing the cradle  62  to the housing  60 . Threaded fasteners, heat tacking, gluing, or other fastening techniques may be employed to attach the cradle  62  to the housing  60 . An energy barrier  68 , such as a rectangular plane integral with the cradle  62 , is also preferably provided in order to minimize light leakage between an emitter element and a receiver element, as described in further detail below. A protective cover (not shown) may also be provided once a circuit board and associated elements have been installed in the cradle  62 .  
         [0026]    One form of circuit board particularly suited for installation in the cradle  62  of FIG. 5 is illustrated in FIG. 6. This circuit board  66  is provided with two openings  70  located for installation about the stanchions  64  of the cradle  62 . Fasteners such as screws may also be employed to locate the circuit board  66  on the stanchions  64 . The circuit board  66  of FIG. 6 is also provided with a slot  72  to enable the board  66  to be installed about the energy barrier  68  of the cradle  62 . Receptacles  74  for electrically interfacing with emitter and detector elements are also provided in conjunction with the circuit board  66 . Active circuit elements may be disposed on the circuit board as necessary in a fashion known to those skilled in the art.  
         [0027]    While the embodiments of FIGS. 1 and 3 are suitable for many applications, in others, the provision of the emitter elements  12  and detector elements  14  remote from the respective lens  42  leads to tolerance stack-up. In other words, any misalignment of an emitter LED  12 , for example, may be exacerbated by the respective lens  42 . Similarly, if a receiver element  14  is not accurately aligned with a respective lens  42 , an obstacle may not be detected or a false alarm may be triggered.  
         [0028]    To address the effect of tolerance stack-up due to misalignment between a lens and an emitter or detector, also referred to as boresight error, it is preferable to minimize the distance between the lens and the respective emitter or detector elements and to eliminate independent movement therebetween. One aspect of the presently disclosed invention addresses this issue by providing an integrated lens module  80 , as depicted in FIG. 7. One or more emitter or detector elements are accurately positioned within a mold for a lens, and the lens material is injected about the emitter or detector, thus forming an integrated module. Assuming the lens has been formed with the respective emitter or detector accurately positioned, such an integrated module eliminates any contribution to tolerance stack-up resulting from lens misalignment. As known to those skilled in the art, the lens module  80  forward surface may be molded to impart any necessary beam shaping, and is formed from a material chosen to have the desired impact (if any) on the energy transmitted therethrough. The active elements may also be associated with the lens after the lens has been fabricated. For instance, a bore may be formed in a pre-molded lens and the active element inserted then secured to the lens.  
         [0029]    Electrical leads  82  in communication with the respective emitter or detector extend from a rear surface of the lens module  80  for connection to the remaining active circuitry of the obstacle detection system. For instance, lens modules  80  may be disposed in communication with receptacles  74  on the circuit board  66  of FIG. 6 and on either side of the energy barrier  68  integral with the cradle  62  of FIG. 5. Physical features such as tabs  84  may be provided in conjunction with the cradle  62  for interference with a corresponding groove or keyway  86  disposed on a surface of the lens module  80 . Accurate alignment of the lens module  80  is thus provided. One tab  84  per lens module  80  is illustrated though more are provided in alternative embodiments.  
         [0030]    Despite the reduction in tolerance stack-up afforded by the lens module  80 , it is mandatory that the housing  40  be accurately positioned with respect to the environment in which the detection system operates. While various positioning and fastening arrangements are available, one particularly useful system includes the use of a variant of the so-called “christmas tree” fastener for mounting the detection system to the door sheet metal. A christmas tree fastener is typically provided as a cylindrical post having plural conical projections disposed along the length of the post. As the post is forced through an aperture of diameter slightly greater than that of the post, the conical projections deform then return to shape, thereby applying back-pressure and resisting extraction from the aperture. The presently disclosed variant on conventional fasteners enables the accurate mounting of an obstacle detection system at a point which is common from vehicle to vehicle, regardless of overlying trim and customization.  
         [0031]    Due to the round cross-section of the conventional christmas tree post, such fasteners are prone to rotation or other movement after being installed. To address this deficiency, the presently disclosed system, in one embodiment, employs at least one and preferably several modified christmas trees  90  to fasten the housing  40 ,  60  to the vehicle trim. As shown in FIG. 8, the modification entails the formation of two parallel grooves  92  on opposite sides of the post  94 . Both grooves are substantially orthogonal to the length of the post  94  and parallel to the conical projections  96 .  
         [0032]    While the prior art has employed a circular aperture for receiving conventional christmas tree fasteners, the presently disclosed system includes the use of a key-hole shaped aperture  100 , such as illustrated in FIG. 9, formed in the vehicle trim  108  or other mounting surface. The modified christmas tree  90  is inserted into a substantially circular opening  102  until the conical projections  96  have passed through the circular opening  102 . The grooves  92  are then aligned with a slot  104  extending in the vehicle trim  108  from the circular opening  102 . Preferably, the conical projection  96  most proximate the grooves  92  is in physical contact with the vehicle trim  108  adjacent the key-hole aperture  100  when the grooves  92  are aligned with the slot  104  to minimize relative movement of the fastener  90 .  
         [0033]    In one embodiment, the slot  104  of the key-hole aperture  100  includes one or more locking tabs  106  which will either physically interfere with the post  94 , thus holding the post in place, or will allow the post to pass therebetween and will then act to resist movement of the post towards the circular opening  102 . In the former case, receptacles (not shown) may be provided within the grooves to receive the tabs  106 .  
         [0034]    While one such modified christmas tree fastener  90  and key-hole shaped aperture  100  may suffice, it is believed preferable to provide plural fasteners  90  and apertures  100  to ensure proper gross alignment for the housing  40 ,  60  of the presently disclosed obstacle detection system.  
         [0035]    Another form of gross alignment mechanism for the detection system is illustrated in FIG. 10. The cradle  62  of FIG. 5 is shown schematically in elevation with respect to the housing  60 . A multi-position bracket  110  enables one end of the cradle to be positioned at one of various positions relative to the housing  60  inner surface. A resilient member  112  such as a leaf spring is preferably provided in conjunction with each position in the bracket to resist movement of the member installed therein. Physical features such as tabs or keys matable with sockets or grooves may also be provided to positively engage the member installed in the bracket  110 . The field of view of the active elements located at the opposite end of a circuit board  66  installed in the cradle  62  is thus adjusted as the cradle  62  is relocated from one bracket  110  position to another. In this case, the stanchions  64  projecting from the housing  60  into the bottom of the cradle  62  are intended primarily to resist lateral motion of the cradle  62 , parallel to the major surface of the housing  60 .  
         [0036]    In an alternative embodiment, the circuit board  66  is engaged on a variant of the cradle  62 , the cradle itself supporting a multi-position bracket  110  such as that shown in FIG. 10. Further still, in the absence of a cradle  62 , a circuit board  20  such as shown in FIG. 1 may be disposed within one of the positions in such a bracket  110  mounted in the housing  40 . Such a bracket  110  may be employed in a further embodiment in conjunction with one or more subsections of a multi-sectioned circuit board  20  as shown in FIG. 1. Moreover, the bracket  110 , while illustrated as a discrete unit, may be provided as a plurality of mutually-parallel ribs on the surface of the vehicle trim.  
         [0037]    Despite the flexibility afforded by the multi-position bracket  110  of FIG. 10 and its ability to be adapted for use with a cradle  62 , a circuit board  66  to be installed in such a cradle  62 , or independent circuit boards  44 ,  46 , a circuit board assembly  20  such as that shown in FIG. 1, it is often necessary to enable further refinement of the field of view of the obstacle detection system&#39;s active elements. To this end, one embodiment of the presently disclosed invention, illustrated in FIG. 11, provides the ability to finely adjust a circuit board  120  orientation in three dimensions relative to a housing.  
         [0038]    The circuit board  120  of FIG. 11 may represent the segmented circuit board  20  of FIG. 1, either of the unitary circuit boards  44 ,  46  of FIG. 3, or the cradle-mounted circuit board  66  of FIG. 6. In addition, the cradle  62  of FIG. 5 may be mounted to the housing  60  in the same manner. In any case, the circuit board  120  is in contact with a projection  124  extending from a mounting surface  122 . The mounting surface  122  may be represented by the housing  40  (FIG. 3), the housing  60  (FIG. 5), or the cradle  62  (FIG. 5). As shown, the projection  124  is frusto-spherical, though any shape affording a pivot point in contact with the circuit board  120  or other surface to be aimed may be substituted. Additionally, while the projection  124  is preferably disposed on the mounting surface  122 , it may also be formed on the circuit board  120  itself and extend into contact with the mounting surface  122 .  
         [0039]    The circuit board  120  is mechanically joined to the underlying mounting surface  122  through the use of at least three height-adjustable fasteners  126  such as screws. Resilient elements  128  such as springs are preferably provided intermediate the circuit board  120  and the mounting surface  122 , about the fasteners  126 , in order to maintain the circuit board  120  in a desired position relative to the mounting surface  122 . By adjusting the height of one or more fasteners  126 , the angle of inclination of the circuit board  120  is manipulated. Depending upon the pitch of the fastener  126  threads, very fine adjustment of the circuit board orientation relative to the housing may be achieved.  
         [0040]    These and other examples of the invention illustrated and described above are intended by way of example and the actual scope of the invention is to be limited solely by the scope and spirit of the following claims.