Abstract:
A method for manufacturing an indicator module for an exterior rearview mirror assembly for a vehicle includes providing a hollow housing formed by injection molding of plastic material and providing a circuit board having a first side and a second side opposite the first side, with at least one light emitting diode disposed at the first side of the circuit board. The circuit board is disposed between a rear end and a front end of the housing such that the first side of the circuit board faces the front end of the housing. With the circuit board disposed between the rear and front ends of the housing, potting material is disposed at and over the second side of the circuit board to seal the rear side of the circuit board. A diffuser element is attached at the front end of the housing and closes the front end of the housing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 15/600,827, filed May 22, 2017, now U.S. Pat. No. 9,754,489, which is a continuation of U.S. patent application Ser. No. 15/278,109, filed Sep. 28, 2016, now U.S. Pat. No. 9,659,498, which claims the filing benefits of U.S. provisional application, Ser. No. 62/233,728, filed Sep. 28, 2015, which is hereby incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to exterior rearview mirror assemblies and, more particularly, to an exterior rearview mirror assembly having a blind spot/object detection indicator and/or a lane change aid (LCA) indicator and/or a turn signal or other indicator at the exterior rearview mirror assembly. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is known to provide a blind spot detection/LCA system for a vehicle that detects the presence of another vehicle or object in the lane next to the host vehicle, where it may be difficult for the driver of the host vehicle to determine whether or not there is another vehicle or object adjacent to the host vehicle. Such a blind spot detection/LCA system often includes a visual indicator that visually indicates the detection of another vehicle or object to the driver of the host vehicle. It is also know to provide a turn signal indicator that is activated when a turn signal is activated by the driver of the equipped vehicle so as to provide an indication of the vehicle turning or changing lanes to the driver of a vehicle in an adjacent lane to the host or subject vehicle or to another person external to the host or subject vehicle. The visual indicator or indicators (commonly a light emitting diode or the like) of such systems is/are often located at the mirror reflective element of the exterior rearview mirror assembly. 
         [0004]    A variety of interior and exterior mirror assemblies with indicators are known in the art, such as described in U.S. Pat. Nos. 5,355,284; 5,788,357; 6,257,746; 6,005,724; 5,481,409; 6,111,683; 6,045,243; 6,264,353; 6,512,624; 6,356,376; 2,263,382; 2,580,014; 3,266,016; 4,499,451; 4,588,267; 4,630,904; 4,623,222; 4,721,364; 4,906,085; 5,313,335; 5,587,699; 5,575,552; 5,436,741; 5,587,699; 5,938,320; 6,700,692 and 5,786,772, and International Publication WO 95/30495, which are all hereby incorporated herein by reference in their entireties. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides a blind zone or blind spot indicator or lane change assist (LCA) indicator or turn signal indicator or other indicator that is disposed at the mirror reflector carrier or back plate of the mirror reflector sub-assembly so as to be positioned at and attached to the mirror reflective element when the back plate is adhered or otherwise attached at the back of the mirror reflective element. Preferably, the signal indicator is provided as a sealed or substantially sealed unit or module that can be snapped into or otherwise attached or secured (preferably mechanically but optionally adhesively) at the mirror back plate (and does so substantially or wholly sealingly to limit or substantially preclude water ingress to the module so that the module and back plate are substantially water impervious), preferably at the mirror sub-assembly manufacturing operation when the mirror reflective element (and any associated heater pad or other item or element) is joined to the mirror back plate. 
         [0006]    The blind zone indicator of the present invention includes a housing with an inner surface or structure that is angled so that light emitted by one or more light sources (such as light emitting diodes) at the back or rear portion of the diffuser and housing is directed generally towards the side of the vehicle for viewing by the driver of the vehicle. The housing and module is attached at the rear of the reflective element (such as at a heater pad adhered at the rear surface of the reflective element or at the rear surface of the reflective element itself or at a rear surface of the mirror back plate) via an adhesive tape or foam tape element that may conform to the reflective element (such as to a curvature of the reflective element) while attaching the module at the rear of the reflective element. The module includes a circuit board, which is arranged generally parallel to the reflective element when the module is attached at the rear of the reflective element. Such an arrangement allows for a lower profile module, while the canted inner surface or structure directs or reflects the light emitted by the light sources or light emitting diodes in the desired direction, such as towards the driver of the vehicle. 
         [0007]    These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a view of an exterior mirror assembly with a blind zone indicator or indicator module in accordance with the present invention, shown as viewed in the direction of travel of the vehicle; 
           [0009]      FIG. 2  is an exploded perspective view of an indicator module disposed at the back plate and heater pad and reflective element in accordance with the present invention; 
           [0010]      FIG. 3  is another exploded perspective view of the indicator module of the present invention, shown disposed at the back plate and heater pad and reflective element; 
           [0011]      FIG. 4  is another exploded perspective view of the indicator module of the present invention, shown disposed at the back plate and heater pad and reflective element; 
           [0012]      FIG. 5  is another exploded perspective view of the indicator module of the present invention, shown disposed at the back plate and heater pad and reflective element; 
           [0013]      FIG. 6  is another exploded perspective view of the indicator module of the present invention; 
           [0014]      FIG. 7  is another exploded perspective view of the indicator module of the present invention; 
           [0015]      FIG. 8  is a perspective and partial sectional view of the indicator module of the present invention at the back plate and reflective element; 
           [0016]      FIG. 9  is an enlarged sectional view of the indicator module and back plate and reflective element of the present invention; 
           [0017]      FIG. 10  is another enlarged sectional view of the indicator module and back plate and reflective element; 
           [0018]      FIGS. 11 and 12  are rear views of the indicator module of the present invention; 
           [0019]      FIG. 13  is a front plan view of the indicator module of the present invention; 
           [0020]      FIG. 14  is a perspective view of the indicator module of the present invention, shown without the rear cover and circuit board; 
           [0021]      FIG. 15  is another exploded perspective view of the indicator module of the present invention; 
           [0022]      FIG. 16  is a perspective view of the indicator module of the present invention; 
           [0023]      FIG. 16A  is a sectional view of the indicator module taken along the line A-A in  FIG. 16 ; 
           [0024]      FIG. 17  is another perspective view and partial sectional view of the indicator module of the present invention; 
           [0025]      FIG. 18  is another perspective view of the indicator module of the present invention; 
           [0026]      FIG. 19  is an end view of a connector of the indicator module of the present invention; 
           [0027]      FIG. 19A  is an enlarged end view of the connector of  FIG. 19 ; 
           [0028]      FIG. 19B  is another enlarged end view of the connector of  FIG. 19 ; 
           [0029]      FIG. 19C  is a sectional view of the indicator module taken along the line C-C in  FIG. 19 ; 
           [0030]      FIGS. 20 and 21  are sectional views of the indicator module of the present invention; 
           [0031]      FIG. 22  is a perspective view of a connector suitable for use with the indicator module of the present invention; 
           [0032]      FIG. 23  is an electrical schematic of a circuit for controlling the light emitting diodes of the indicator module of the present invention, without a constant current circuit; 
           [0033]      FIG. 24  is an electrical schematic of another circuit for controlling the light emitting diodes of the indicator module of the present invention; 
           [0034]      FIG. 25  is a plan view of a plurality of circuit boards for use with the indicator module of the present invention; and 
           [0035]      FIG. 26  is an enlarged plan view of a finished circuit board of  FIG. 25 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0036]    Referring now to the drawings and the illustrative embodiments depicted therein, an exterior rearview mirror assembly  10  for a vehicle includes a mirror reflector sub-assembly  12  and a mirror shell or casing  14  ( FIG. 1 ). Mirror assembly  10  is mounted at the side  16   a  of a host or subject vehicle  16 . The mirror reflector sub-assembly  12  includes a mirror reflective element  18  and a mirror reflector carrier or back plate  20  ( FIGS. 2-5 ) attached to or mounted to or adhered to a rear surface of the mirror reflective element  18 . Mirror assembly  10  includes an indicator or display element or device or signal indication module  22  that is disposed at back plate  20  and behind reflective element  18 , and that is operable to provide a display or indication  23  at the reflective element for viewing the display or indication through the mirror reflective element (such as via a window established, such as via ablation of the mirror reflector coating, at the reflective element or such as via viewing through a partially light transmissive and partially light reflective transflective mirror reflector of the reflective element). 
         [0037]    Signal indication module  22  includes a housing  24  (that is received into or attached to an indicator receiving portion or mounting portion or structure of back plate  20  so as to be disposed generally at a rear surface of a planar portion of back plate  20 ) and an illumination source or indicator, such as one or more light emitting diodes (LEDs) or other suitable illumination source. In the illustrated embodiment, the light source comprises three light emitting diodes  28 . Housing  24  of signal indication module  22  includes an internal structure  26  having an inner reflective surface  26   a  that is formed to angle or reflect the light emitted by the light emitting diodes  28  (disposed at respective apertures or holes  26   b  formed through the internal structure  26 ), such that light emitted by the light emitting diodes, when activated or energized or powered, is directed generally towards and is principally viewed by the driver of the vehicle. The signal indicator module may utilize aspects of the modules or units described in U.S. Publication No. US-2016-0078768, which is hereby incorporated herein by reference in its entirety. 
         [0038]    In the illustrated embodiment, the signal indication module  22  comprises a blind zone indicator for an object detection in a blind spot detection system or LCA system (with the indicator module being angled and operated to provide a signal that is principally viewable by the driver of the vehicle). Optionally, the indicator module may also or otherwise include a display device or indicator for a turn signal indicator or signal indication module or other indicator device. The blind zone or signal indicator assembly or indicator module of the present invention may utilize aspects of the indicators described in U.S. Pat. Nos. 8,786,704; 8,058,977; 7,944,371; 7,581,859; 7,038,577; 6,882,287; 6,198,409; 5,929,786 and/or 5,786,772, and/or International Publication Nos. WO 2007/005942 and/or WO 2006/124682, which are all hereby incorporated herein by reference in their entireties. 
         [0039]    As shown in  FIGS. 2-10 , indicator module  22  includes housing  24  that is open at the front and that has a front or attaching surface  24   a  that is generally planar and that is configured to be received through the aperture  20   a  in the back plate  20 . In the illustrated embodiment, a connector portion or receptacle  24   c  of the housing  24  also provides a portion of the generally planar attaching surface. The back plate aperture is formed to receive the triangular shaped light reflecting portion of the housing and the connector portion of the housing therein. An adhesive tape or element or foam tape element  38  is shaped to correspond with the shape of the front surface  24   a  and has an aperture  38   a  formed therethrough that corresponds with the opening of the front portion  24   a  of the housing and that corresponds with a diffuser element  36 . The tape  38  is configured to be adhered to the rear surface of a heater pad  40  (with the aperture  38   a  corresponding with an aperture  40   a  of the heater pad) and to be adhered to the front surface  24   a  of the housing  24  (including around the triangular-shaped aperture and at the connector portion) to attach the module  22  at the heater pad  40 , which is adhered to the rear surface of the reflective element  18 . 
         [0040]    The adhesive tape  38  may comprise any suitable adhesive or foam tape that may conform to the front surface of the module housing and to the heater pad and/or rear surface of the reflective element (such as to a curved rear surface for a non-planar reflective element or the like) while sealing and adhering the module housing at the rear of the reflective element. For example, the foam tape may comprise a double coated polyethylene foam tape of the types commercially available from 3M of St. Paul, Minn., which provide a conformable closed cell foam with a rubber adhesive or a high strength acrylic adhesive, such as 3M&#39;s 4462 W, 4462B, 4466 W, 4466B, 4492G, 4492 W, 4492B, 4496 W or 4496B double coated polyethylene foam tapes or the like. The foam tape may comprise a dark colored tape (such as black) to limit or substantially preclude passage of light therethrough. 
         [0041]    The diffuser element  36  is shaped to attach at the front surface of the housing  24  and/or at the rear surface of the reflective element or at the rear surface of the heater pad, so as to be disposed at the aperture of the foam tape, whereby light emitted by the LEDs  28  is directed through the diffuser element  36  and generally towards the driver of the vehicle. The diffuser element  36  may comprise any suitable diffuser element. For example, the diffuser element may comprise a diffuser film or element of the types commercially available from Keiwa Inc. of Tokyo Japan, such as, for example, Keiwa&#39;s PBS-series of diffuser films or the like. The diffuser element thus is at least partially transmissive of visible light and also functions as a cover element at the front surface of the housing  24  to close the opening of the housing circumscribed by the attaching surface. 
         [0042]    The adhesive tape comprises a cut out or shaped tape element that adhesively attaches at the attaching or front surface of the housing and at the heater pad or reflective element. The adhesive tape may comprise a double sided tape element, such as a pressure sensitive adhesive (PSA) element, where a film is peeled off one or both sides of the adhesive tape to expose the adhesive when attaching/adhering the tape element to the front surface of the housing and/or the rear surface of the heater pad or mirror reflective element. The indicator module may, when shipped, have the adhesive element attached at the front or attaching surface of the housing, whereby, when assembling the mirror reflective element sub-assembly, an operator may peel the film off the front surface of the adhesive tape element at the front of the housing to expose the adhesive and may insert the module into the aperture of the mirror back plate and press the module against the rear surface of the heater pad or the rear surface of the mirror reflective element to attach the module at the rear of the reflective element. Optionally, the front surface of the adhesive tape element may adhesively attach at the rear surface of the mirror back plate (such as for applications where the aperture through the back plate generally corresponds with the triangular-shaped (or other shape) opening of the adhesive tape element and/or front opening of the housing and/or aperture through the heater pad and/or the like), whereby the attaching surface of the housing and the adhesive tape element at least partially circumscribe the aperture formed through the mirror back plate. 
         [0043]    The adhesive tape may comprise a foam tape that has a crush of at least about 0.25 mm, preferably about 0.5 mm, which aids in the assembly of the module at the back plate due to over-travelling of the module when snapping it to the back plate. The foam tape acts as a seal around the periphery of the molded housing or white diffuser, and functions as a light blocker to limit or prevent light leakage behind the mirror reflective element. The foam tape may be applied at the heater pad or at the back plate or at the module, depending on the particular application of the module and preferred assembly processes. 
         [0044]    The cut out triangle-shaped aperture in the adhesive element is about 1.5 times larger than an ablated triangle formed through the mirror reflector of the reflective element. This allows the ablated triangle at the glass and the back plate to be slightly mis-located and not have winking (black tape visible from the glass side). The tape diffuser works best when it is disposed subflush to the molded housing or diffuser (i.e., is received in a recess at the front portion of the housing). Such an arrangement provides the least amount of light leakage at the diffuser element. 
         [0045]    Signal indication module  22  includes a circuit element  32 , such as a printed circuit board or the like (such as a rigid or flexible circuit board or element), with the illumination sources or LEDs  28  disposed thereat (such as surface mounted or otherwise disposed LEDs or other suitable or equivalent light source), although more illumination sources or LEDs may be provided while remaining within the spirit and scope of the present invention. The circuit element or PCB includes circuitry including resistors and/or voltage reducing circuits and/or ballast circuitry and/or DC to DC converters and/or the like (such as by utilizing aspects of the circuits and light sources described in U.S. Pat. No. 7,195,381, which is hereby incorporated herein by reference in its entirety). Circuit element  32  is attachable at or positioned at a rear portion  24   b  of the housing  24  (such as received at a pocket or receiving portion formed at the rear portion of the housing  24 ), whereby the illumination sources  28  are located at the rear portion of the housing and at an opposite end of the housing from the reflective element  18 . When the circuit element  32  is disposed in or received at the rear of the housing  24 , a potting element or material  31  may be disposed over the circuit element to seal the circuit element in the housing. 
         [0046]    The illumination sources or LEDs  28  are disposed or arranged at the circuit element such that the LEDs  28  are disposed at respective apertures or holes  26   b  formed through the internal structure  26  of the housing  24 . For example, and such as can be seen with reference to  FIG. 6, and 14-18 , the LEDs may comprise three triangularly arranged LEDs and the holes  26   b  may be similarly triangularly arranged to accommodate the respective LEDs. 
         [0047]    Thus, when the indicator module is attached at the reflective element (such as via the foam tape), the indicator module circuit element or PCB is parallel to the mirror reflective element, which provides enhanced packaging. With such a configuration, the lower limit of the thickness of the module is actually driven by the waterproof connector. When attached at the rear of the reflective element, the module is aimed approximately 30 degrees from normal towards the inside of the vehicle. The ablation percentage on the glass is between about 85 percent transmissive and about 40 percent transmissive to provide a desired or appropriate balance between hiding the diffuser and letting enough light through for an efficient system. For example, the minimum light levels emitted by the module and viewable by the driver of the vehicle when operated during daytime lighting conditions may be at least about 1,500 Nits or cd/m 2 , or at least about 6,000 Nits or cd/m 2 , depending on the particular application of the indicator module. The circuit element may use a transistor based constant current circuit in order to have the same output for different voltages. 
         [0048]    When used and operated in an exterior rearview mirror assembly on a vehicle, the light intensity of the illuminated icon or diffuser element, as seen by a driver of the equipped vehicle viewing the illuminated icon at the reflective element, is varied (such as by pulse width modulation of the voltage applied to the light source or sources of signal indication module  22 ) in accordance with the ambient light level (such as detected by the likes of a photodetector or photosensor) that the equipped vehicle is operating in. Thus, for example, as daytime lighting transitions to dusk and then to night, the display intensity can either progressively/continually reduce or may stepwise reduce as ambient lighting decreases. Thus, for example, when the equipped vehicle is operating on a dark rural road at night, the display intensity may be less than about 1,000 Nits, and preferably less than about 800 Nits and more preferably less than about 500 Nits or thereabouts, so as to limit or avoid glaring of the night-adapted vision of the driver. 
         [0049]    Circuit element  32  includes electrical terminals or connectors  32   a  that are in electrical or conductive communication with illumination sources  28  and that electrically connect the circuitry and light sources to electrical power or electrical control at the mirror assembly when the signal indication module is attached to the back plate and installed at the mirror casing. As can be seen with reference to  FIG. 7 , the terminals or connectors  32   a  extend from the circuit element  32  and, when the circuit element is received in the housing, are disposed at or in a sealed connector receptacle  24   c  of the housing  24 . As can be seen with reference to  FIGS. 14 and 15 , the receiving portion or rear portion  24   b  of the housing  24  is configured to receive the circuit element  32  therein, whereby the terminals  32   a  are inserted through apertures  24   d  ( FIG. 14 ) at the housing wall between the receiving portion and the connector portion. Thus, when the circuit element  32  is disposed in the receiving portion, the circuit element can be angled as it is inserted into the receiving portion so that the terminals are inserted through the apertures  24   d , whereby the circuit element may be pressed into place in the receiving portion and sealed or encased therein (such as via cover element  31  or the like. Optionally, connectors  32   a  connect to a mating connector  33  ( FIG. 22 ), which is disposed at an opening or connector receptacle in housing  24  for electrical connection to a wire harness connector of the mirror assembly or vehicle to provide power and/or control to the signal indication module when the module is mounted to or attached to the back plate and installed at the mirror casing. 
         [0050]    The mirror back plate  20  comprises structure  20   b  at least partially circumscribing said aperture  20   a  formed through the mirror back plate for receiving at least a portion of the housing  24  therein. The housing  24  is at least partially received in the structure of the mirror back plate, which is formed to receive the first portion and the connector portion of the housing at least partially therein. An outer end or wire harness connecting end of the connector portion of the housing is disposed at an opening  20   c  (see  FIG. 11 ) in the structure  20   b  of the mirror back plate  20  to facilitate connection of the connector portion  24   c  with the connector of the wire harness of the exterior rearview mirror assembly to electrically connect the wire harness to circuitry of the circuit board. 
         [0051]    Signal indication module  22  includes a diffuser element  36  that is disposed at a forward end region or portion  24   a  of housing  24  so as to be disposed at the rear of the reflective element when the signal indication module  22  is attached at the back plate  20  and heater pad and rear surface of the reflective element. Optionally, the walls or surfaces of the inner surface or internal structure  26  of housing  24  may comprise highly specularly and/or diffusely light reflecting inner surfaces so as to enhance diffuse reflection of incident light to enhance the intensity of illumination that exits the indicator module through the indicia element. For example, the housing wall may be molded of a white plastic material or resin, such as an ABS or an ABS/polycarbonate polymeric resin material or the like. The housing may comprise a polymeric housing molded via a unitary injection molding process. 
         [0052]    The diffuser cover or film or element  36  is disposed at the front (or rear) of the module to diffuse the light emitted by the illumination sources  28  to provide more uniform illumination (when the illumination sources are activated) as viewed by the driver of the vehicle. The diffuser element  36  may be attached or adhered at the front end portion or surface of the housing  24  (and the diffuser element may also or otherwise be adhered to the rear of the reflective element when the indicator module is attached at the back plate). 
         [0053]    Illumination sources  28  are energized to direct or emit illumination along the housing so that the indicator/light is viewable through the reflective element. The illumination sources  28  may comprise any suitable illumination source or light source. For example, the illumination sources may comprise one or more light emitting diodes (LEDs) or organic light emitting diodes (OLEDs) or the like, or may comprise one or more power LEDs, such as of the types described in U.S. Pat. No. 7,195,381, which is hereby incorporated herein by reference in its entirety, or may comprise a LUXEON® LED available from LUMILEDS™ or other suitable light source. 
         [0054]    The illumination sources  28  may be controlled or operated via any suitable circuitry and/or control. For example, a circuit may be operable to power the LEDs with a constant current circuit (such as shown in  FIGS. 23 and 24 ). When powered, the LEDs may provide up to about 11,000 nits minimum average brightness at nominal supply voltage (such as between about 9 and 16 volts DC, such as about 13.5 Volts DC), with a generally uniform illumination. The LEDs may emit colored light or white light, depending on the particular application, and may operate at a maximum current of about 100 mA and may be operable at temperatures between about −30 degrees C. and +65 degrees C. 
         [0055]    Optionally, a heater pad  40  ( FIGS. 2-5 and 10 ) may be provided at the rear surface of the glass substrate of the reflective element and between the backing portion of the back plate and the reflective element to provide an anti-fogging of de-fogging feature to the exterior mirror assembly (such as by utilizing aspects of the heater elements or pads described in U.S. Pat. No. 7,400,435, which is hereby incorporated herein by reference in its entirety). The back plate and/or heater pad may include suitable electrical connectors and connections incorporated therein (such as by utilizing aspects of the mirror assembly described in U.S. Pat. No. 7,400,435) for electrically connecting the heater pad and/or indicator module and/or display element (or other suitable electrical connectors may be utilized, such as electrical leads or wire harnesses or pigtails or other separate connectors or cables or the like). The heater pad may include a hole or opening or aperture therethrough (or optionally a window or transparent or translucent or diffuse portion of the heater pad, such as a clear or diffusing transparent polyester flexible plastic film or element) that generally corresponds to the aperture of the back plate when the heater pad is attached to the rear surface of the glass substrate of the reflective element (such as via an adhesive such as a pressure sensitive adhesive) and when the back plate is attached to the rear surface of the heater pad. Optionally, and desirably, the heater pad may include an adhesive layer (such as a pressure sensitive adhesive layer) at its rear surface for adhering the back plate to the heater pad and thus to the rear surface of the glass substrate of the reflective element. 
         [0056]    For applications where the indicator module attaches at the rear of the heater pad (such that the portion of the heater pad that circumscribes the aperture through the heater pad is contacted by the foam tape element), the aperture through the heater pad may generally correspond with the opening of the housing that is circumscribed by the attaching surface of the housing. For example, and such as shown in  FIGS. 2-5 , the aperture  40   a  through the heater pad  40  is smaller than the foot print of the attaching surface  24   a  of the housing  24  (and the aperture  40   a  generally corresponds with the aperture  38   a  of the foam tape element  38 ), such that the attaching surface  24   a  attaches to one side of the foam tape element  38  and the other side of the foam tape element  38  attaches to the rear of the heater pad  40 . Optionally, for applications where the indicator module attaches at the rear surface of the mirror reflective element, the aperture or hole through the heater pad is at least as large or larger than the foot print of the attaching surface of the housing (which is about the same as or slightly smaller than the aperture through the mirror back plate) to provide clearance for the attaching surface of the housing to pass through the back plate aperture and through the aperture of the heater pad to attach at the rear surface of the mirror reflective element via the tape element. 
         [0057]    The inner surface of the housing may be polished to enhance reflection of the emitted light to enhance viewability of the icon through the mirror reflective element. Optionally, the polishing or surface finish of the diffuser element may be selected to provide the desired degree of reflectivity and light emittance by the indicator module. Optionally, the indicator module may be operable to provide a desired brightness or intensity of illumination and the desired directionality. The relative brightness of the LEDs may be balanced with current shunts and the LEDs may be driven with less current which may help to meet light reduction specifications. 
         [0058]    The back plate and/or signal indication module may be formed to provide a desired shape for viewing of the light passing through the reflective element or the mirror reflective element preferably includes one or more iconistic display areas or masks so that the illumination is viewable and discernible at the reflective element by the desired or targeted viewer. The mirror assembly thus may provide an iconistic display for an object detection/LCA system and/or an iconistic display for a turn signal indication, and/or may provide other displays or illumination devices, without affecting the scope of the present invention. 
         [0059]    The indicator housing portion has its inner reflective surface angled so as to direct the light toward the vehicle and toward a driver or occupant of the host vehicle. More particularly, the light beam emitted from the blind spot signal indicating module and transmitted through the reflective element is angled so as to have its principle beam axis directed generally toward the eyes of a driver seated in the interior cabin of the host vehicle. As shown in  FIGS. 9 and 10 , the housing may have its inner surface angled so as to direct or reflect the principal beam direction of the emitted light at an angle generally towards the driver of the vehicle, such as at an angle of at least about 15 degrees normal to the reflective element, preferably at least about 20 degrees normal to the reflective element, preferably about 25 degrees normal to the reflective element, and no more than about 35 degrees normal to the reflective element, such as at an angle between about 20 and 30 degrees, such as, for example, at an angle of about 24.5 degrees from normal or perpendicular to the glass (or about 65.5 degrees relative to the rear surface of the reflective element or thereabouts) so as to direct or guide light through the passageway and in the desired direction toward the side of the equipped/host vehicle for viewing the object/LCA indication principally or solely by the driver of the host vehicle. Should, however, the signal module be a turn signal module, then the indicator module may be configured to direct or reflect light generally outboard from the side of the vehicle so as to direct or guide light through the passageway and in the desired direction away from the side of the equipped/host vehicle for viewing the turn indication principally or solely by the drivers of overtaking vehicles and principally other than by the driver of the host vehicle. 
         [0060]    The indicator or display is operable to provide three states from the driver&#39;s point of view. First, a display state “off” is provided where the indicator function is deactivated or the function is outside the specified functional range or there is no potentially hazardous vehicle in the adjacent lane. A display state where the display is continuously illuminated (such as an amber color or yellow color or the like) may be provided (where the indicator may be subliminally perceived, i.e., only by focused observation of the mirror), when the adjacent lane is occupied by a vehicle in the blind spot or a vehicle is approaching at speed from behind, meaning that it would be dangerous to change lanes into this lane (and in situations where the driver has not actuated a turn signal indicator of the vehicle). A third display state may provide a flashing indicator (such as a bright flashing yellow or amber indication), where the flashing sequence may be selected depending on the particular application of the indicator module. The display is active and can be perceived peripherally even if the driver is looking straight ahead. This flashing display is provided when the adjacent lane is occupied by a vehicle in the blind spot or a vehicle is approaching at speed from behind, and where the driver has actuated a turn signal indicator to show that he or she plans to change lanes. In such a situation, the indicator module warns against such a lane change. 
         [0061]    The display element or icon may be illuminated with a basic brightness at a minimum actuation or dimming level when permanently actuated. For prolonged actuation with maximum icon display intensity, the display element may be illuminated at a brightness of at least about 4,000 cd/m 2  (±20%). In flashing actuation, the display elements may each be illuminated at a brightness of at least about 6,000 cd/m 2  (±20%). These values are mean values over the entire display surface. The deviation of ±20% applies to the maximum and minimum value of all surface points within this area for the achievement of a substantially homogeneous appearance. This homogeneity criterion applies across the entire brightness range (basic brightness through maxi-mum brightness). For darker light conditions, the resolution of the individual brightness levels may be finer (below about 50 cd/m 2 , the resolution per level may not exceed approximately 1.2 cd/m 2 ), as the human eye is more sensitive to changes in brightness in the lower brightness range. In the upper brightness range (above approximately 50 cd/m 2 ) the resolution can be coarser (the resolution per level can be up to about 15 cd/m 2 ). 
         [0062]    A corresponding scaling from the input value to the maximum brightness of the basic brightness of about 4,000 cd/m 2  may be implemented in the form of a suitable lookup table, where at least 10 interpolation points may be provided. Between the individual interpolation points, transition is by means of linear interpolation. In addition, it may be ensured that, during each possible change of the brightness request by the partner control unit, the brightness adjustment of the LIN module does not lead to a jump in the brightness level that is perceptible to the driver. The requested brightness may be achieved in a time period of less than about 0.5 seconds or thereabouts. 
         [0063]    The back plate may comprise any suitable back plate structure, and may be molded or formed, such as by injection molding, so as to provide the display receiving portion and a generally planar backing portion that attaches to the rear surface of the reflective element (such as via adhesive or other suitable attachment means). As shown in  FIGS. 2-5 , back plate  20  includes an aperture or hole at the mounting portion such that when signal indication module  22  is attached to the mounting portion of back plate  20 , the front end of housing  24  and the diffuser element  36  of signal indication module  22  are positioned at and through the aperture and at or against the rear surface of the reflective element substrate. Preferably, back plate  20  is molded of a substantially dark or opaque or black material, such as from an ABS or PC-ABS or polycarbonate polymeric resin material or from any other suitable material such as known in the exterior rearview mirror art, so as to be substantially opaque such that light does not pass through the opaque back plate and the indicator mounting portion. 
         [0064]    Optionally, and desirably, the indicator mounting portion or structure may be unitarily or integrally formed with back plate  20  and may be formed with a pocket for receiving or partially receiving housing  24  to locate signal indication module  22  at the generally planar backing portion of back plate  20 . For example, the pocket may receive housing  24  at least partially therein, and the indicator mounting portion may secure (such as by snapping or the like) the housing at or in the pocket of the indicator mounting portion of back plate  20  (such as via tabs on the back plate engaging flanges or surfaces of the module housing to snap the signal indication module  22  to the back plate with the forward end of the housing and the indicia element urged toward and against the rear surface of the reflective element). The back plate and its indicator mounting portion and aperture may be formed in the plastic injection molding process. 
         [0065]    Optionally, the back plate may include a perimeter framing portion or bezel portion that extends around the perimeter edges of the reflective element to support the reflective element and frame the reflective element at the mirror assembly (such as by utilizing aspects of the mirror assemblies described in U.S. Pat. Nos. 8,058,977 and/or 7,581,859, which are hereby incorporated herein by reference in their entireties). The perimeter bezel portion may be narrow or small depending on the particular application of the reflective element and mirror reflector sub-assembly. Optionally, the mirror reflector sub-assembly may comprise a bezelless or frameless reflective element (such as the types described in U.S. Publication No. US-2006-0061008 and/or U.S. Pat. Nos. 7,184,190 and/or 7,255,451, and/or International Publication No. WO 2006/124682, which are hereby incorporated herein by reference in their entireties), whereby the back plate may not include a perimeter framing portion or bezel portion around the perimeter of the reflective element. 
         [0066]    Back plate  20  may include an attachment element or elements (such as an annular ring or tab or annular prongs or annular snaps or the like) formed or established at the rear of the backing portion for attaching the back plate  20  and reflective element  18  to a mirror actuator (such as a mirror actuator as known in the art and/or as described in U.S. Pat. Nos. 7,080,914; 7,073,914; 6,916,100; 6,755,544; 6,685,864; 6,467,920; 6,362,548; 6,243,218; 6,229,226; 6,213,612; 5,986,364 and/or 5,900,999, which are hereby incorporated herein by reference herein in their entireties), which is adjustable or operable to adjust a viewing angle of the mirror reflective element. When the mirror reflective element is canted or angled partially toward the driver of the host vehicle (which is typically the orientation of the reflective element during use so as to provide a generally rearward field of view to the driver of the host vehicle), there is sufficient space within the mirror casing at or near the outboard portion of the mirror assembly for the indicator mounting portion and signal indication module. The back plate and signal indication module of the present invention thus utilizes the space within the mirror head or casing that is already available and typically not used or occupied by other components. 
         [0067]    Optionally, and preferably, indicator element or display element or signal indication module may snap into the end or pocket of the indicator mounting portion or may otherwise be attached or stuck at the indicator mounting portion, and may have a gasket or seal at the signal indication module to provide a substantially water proof or water resistant or water tight seal at the signal indication module, whereby the signal indication module may be sealed at the indicator mounting portion, such as by gluing or pressing or screwing or gasketing or hermetically sealing or otherwise substantially sealing the signal indication module at the indicator mounting portion. The signal indication module may comprise a self-contained, unitary, sealed or substantially sealed, indicator module that includes the housing and cover element, an illumination source (such as one or more LEDs or the like), a DC converter with a voltage dropping resistor (such as described in U.S. Pat. Nos. 7,195,381; 6,902,284 and/or 6,690,268, which are hereby incorporated herein by reference in their entireties) and the electrical terminals or connector. The signal indication module thus may be connected to a power source and may be activated or energized to illuminate the display for viewing by the driver of the vehicle. Optionally, the electrical connections to the signal indication module may be made while the signal indication module is attached to the mirror assembly, such as via a plug and socket type arrangement or configuration, and such as by utilizing aspects of the mirror assembly described in U.S. Pat. No. 6,669,267, which is hereby incorporated herein by reference in its entirety. The unitary signal indication module may include or utilize aspects of various light modules or systems or devices, such as the types described in U.S. Pat. Nos. 7,581,859; 6,227,689; 6,582,109; 5,371,659; 5,497,306; 5,669,699; 5,823,654; 6,176,602 and/or 6,276,821, and/or International Publication No. WO 2006/124682, which are hereby incorporated herein by reference in their entireties. 
         [0068]    The blind spot indicators of the present invention thus are operable to provide an indication to the driver of the host vehicle that an object or other vehicle has been detected in the lane or area adjacent to the side of the host vehicle. The blind spot indicator may be operable in association with a blind spot detection system, which may include an imaging sensor or sensors, or an ultrasonic sensor or sensors, or a sonar sensor or sensors or the like. For example, the blind spot detection system may utilize aspects of the blind spot detection and/or imaging systems described in U.S. Pat. Nos. 7,881,496; 7,720,580; 7,038,577; 6,882,287; 6,198,409; 5,929,786 and/or 5,786,772, and/or of the reverse or backup aid systems, such as the rearwardly directed vehicle vision systems described in U.S. Pat. Nos. 5,550,677; 5,760,962; 5,670,935; 5,877,897; 6,201,642; 6,396,397; 6,498,620; 6,717,610; 6,757,109 and/or 7,005,974, and/or of the automatic headlamp controls described in U.S. Pat. Nos. 7,526,103; 5,796,094 and/or 5,715,093, and/or of the rain sensors described in U.S. Pat. Nos. 6,250,148 and/or 6,341,523, and/or of other imaging systems, such as the types described in U.S. Pat. Nos. 6,353,392 and/or 6,313,454, which may utilize various imaging sensors or imaging array sensors or cameras or the like, such as a CMOS imaging array sensor, a CCD sensor or other sensors or the like, such as the types disclosed in commonly assigned, U.S. Pat. Nos. 5,550,677; 5,760,962 and/or 5,796,094, and/or International Publication No. WO 2004/047421, with all of the above referenced U.S. patents and PCT applications being commonly assigned and being hereby incorporated herein by reference in their entireties. 
         [0069]    The indicator icon, when the light source of the indicator is activated, may be viewable through a transflective mirror reflector of the mirror reflective element or may be viewable through a window that is formed (such as via ablation) at least partially through the mirror reflector of the mirror reflective element. The reflective element of the rearview mirror assembly may comprise an electro-optic or electrochromic reflective element or cell, such as an electrochromic mirror assembly and electrochromic reflective element utilizing principles disclosed in commonly assigned U.S. Pat. Nos. 7,626,749; 6,690,268; 5,140,455; 5,151,816; 6,178,034; 6,154,306; 6,002,544; 5,567,360; 5,525,264; 5,610,756; 5,406,414; 5,253,109; 5,076,673; 5,073,012; 5,117,346; 5,724,187; 5,668,663; 5,910,854; 5,142,407; 4,712,879; 7,195,381 and/or 7,255,451, and/or International Publication No. WO 2006/124682, which are all hereby incorporated herein by reference in their entireties. 
         [0070]    Optionally, the reflective element may include a perimeter metallic band, such as the types described in U.S. Pat. Nos. 7,255,451 and 7,274,501, and International Publication Nos. WO 2004/026633 and/or WO 2004/042457, which are all hereby incorporated herein by reference in their entireties. Optionally, the reflective element may include indicia formed at and viewable at the reflective element, such as by utilizing aspects of the reflective elements described in U.S. Pat. No. 7,626,749, which is hereby incorporated herein by reference in its entirety. 
         [0071]    Optionally, the reflective element may comprise a single substrate with a reflective coating at its rear surface, without affecting the scope of the present invention. The mirror assembly thus may comprise a prismatic mirror assembly or planar or non-planar mirror or other mirror having a single substrate reflective element, such as a mirror assembly utilizing aspects described in U.S. Pat. Nos. 7,249,860; 6,318,870; 6,598,980; 5,327,288; 4,948,242; 4,826,289; 4,436,371 and/or 4,435,042, and/or International Publication No. WO 2004/103772, which are hereby incorporated herein by reference in their entireties. Optionally, the reflective element may comprise a conventional prismatic or flat reflective element or prism, or may comprise a prismatic or flat reflective element of the types described in International Publication Nos. WO 2004/026633 and/or WO 2004/103772, and/or U.S. Pat. Nos. 7,420,756; 7,249,860; 7,255,451 and/or 7,338,177, which are all hereby incorporated herein by reference in their entireties, without affecting the scope of the present invention. 
         [0072]    Changes and modifications to the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law.