Abstract:
A mirror includes a housing, an electrochromic mirror subassembly in the housing including front and rear transparent elements, a layer of electrochromic material associated with the front and rear transparent elements, a reflector layer associated with the rear transparent element, with a portion of the reflector layer defining an opening, and an indicia panel covering the opening and configured to form a visual display. The visual display includes a panel with a discrete number of pre-formed letters and symbols. At least one light source is positioned in the housing to pass light through the indicia panel and the opening of the mirror subassembly to selectively illuminate the visual display. The plurality of light-emitting devices being a number that is equal to or less than the discrete number. The at least one light source emits a light matched in color to the indicia panel so that a maximum of light from the at least one light source passes through the indicia panel and is visible to a vehicle driver. Optimally, the light sources emit an amber colored light, and the indicia panel includes a diffusing layer also having an amber color.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of application Ser. No. 09/586,813, filed Jun. 5, 2000, entitled REAR VIEW MIRROR WITH DISPLAY, which is a continuation-in-part of application Ser. No. 09/311,029, filed May 13, 1999, entitled REAR VIEW MIRROR DISPLAY, which is a continuation-in-part of application Ser. No. 09/172,393, filed Oct. 14, 1998, entitled REARVIEW MIRROR DISPLAY. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to vehicle rearview mirrors, and more particularly related to the display of information on a rearview mirror assembly. 
     BACKGROUND OF THE INVENTION 
     Modern cars and trucks include rearview mirrors mounted inside and outside of the vehicle. One type of conventional interior rearview mirror comprises a prismatic mirror that can be switched from a first orientation suitable for normal driving conditions to a second orientation, which reduces glare caused by headlights of vehicles approaching from the rear. 
     Recently, electrochromic rearview mirrors have been developed which automatically change from a full reflectance mode during the day to a partial reflectance mode during the night for glare protection. Electrochromic rearview mirrors typically comprise a relatively thin electro-optic medium sandwiched and sealed between two glass elements. In most assemblies, when the electro-optic medium is electrically energized, it darkens and absorbs an increasing amount of light as the applied voltage is increased. When the electrical voltage is removed, the mirror returns to its clear state. Examples of such automatic rearview mirrors are disclosed in U.S. Pat. Nos. 4,902,108; 4,917,477; 5,128,799; 5,202,787; 5,204,778; 5,278,693; 5,280,380; 5,282,077; 5,285,060; 5,294,376; 5,682,267; 5,689,370; 5,448,397; 5,451,822; and 5,818,625 each of which is assigned to the assignee of the present invention and each of which is incorporated herein by reference. 
     In the past, information such as the words “HEATED” or “OBJECTS IN MIRROR ARE CLOSER THAN THEY APPEAR” have been used on many vehicle rearview mirrors. In addition, some types of automatic rearview mirrors have included compass and temperature readings. However, such conventional rearview mirror displays typically comprise a glossy planar surface, which makes the display difficult to read. Furthermore, such conventional displays are often difficult or impossible to read by some occupants of a vehicle. For example, interior rearview mirrors are typically angled toward the driver and away from the front seat passenger, thereby obstructing the front seat passenger&#39;s ability to see the display. In addition, selectable information displays commonly used in automobile interiors comprise complex electronic assemblies. This type of display is not only expensive, but also more prone to failure due to the number and complexity of components. 
     In addition to the problems and concerns discussed above with displays on mirrors, there are additional problems that need to be addressed. One way of forming the individual letters of the words “HEATED” and “OBJECTS IN MIRROR . . . ” is to apply reflector material to an electrochromic mirror subassembly as a uniform layer, and then selectively remove portions of reflector material to form the shape or image of detailed alphanumeric and symbolic indicia in the reflector material. However, it is difficult to remove the reflector material in a manner that accurately and consistently forms all parts of small letters and symbols, such that the removal process potentially results in significant scrap. This scrap can be very expensive because, not only does a significant percentage of scrap result from imperfect indicia images, but further the mirror subassembly is relatively expensive work-in-process at that point in the manufacturing process. Concurrently, the scrap is difficult to repair. 
     Another problem is that, even if reflector material is accurately removed to form the indicia image, many manufacturers want color in their displays to improve their customer appeal. Colored translucent labels have been used in the past in vehicles, such as in instrument panels, to create visual displays. However, there are problems with known prior art labels used in the environment of a mirror. For example, stick-on labels using adhesive may partially delaminate from glass mirror element over time, leading to poor appearance where the released adhesive has a discontinuous and patchy appearance. Also, the adhesive can trap air during the installation process, leading to immediate poor appearances or leading to in-service delamination problems as the stick-on label and its carrier are thermally cycled. 
     Alignment of components and displays in mirrors is another important consideration in regard to customer acceptance. Display information that is non-parallel and angled relative to a perimeter of the mirror can result in a customer forming a very poor opinion of the quality of a vehicle, even though the mirror is fully functional. Further, misalignment can be very aggravating to a customer, because the customer sees the misalignment problem every time they look in the mirror, which occurs every time they are in the vehicle. 
     Another problem is accurate positioning and retention of a printed circuit board in the mirror housing. Printed circuit boards carry circuits used in electrochromic mirrors to control darkening for glare protection, and also carry other circuits and sensors, such as for daylight sensing, keyless entry signal sensing, information displays, and the like. It is important that the printed circuit board be accurately positioned so that any light sources and sensors carried thereon are accurately located, and so that any control buttons for the mirror that are mounted on the printed circuit board and protrude through a face of the housing are also properly and accurately positioned. Additionally, it is noted that the printed circuit board should be firmly held in a manner preventing rattling, but in a manner not leading to breakage, fracturing, or undue bending or stressing of the printed circuit board during assembly and during thermal cycling while in service. 
     Another less obvious problem concerns secondary reflections and scattering of light within transparent layers in the mirror subassembly. Electrochromic mirror subassemblies include a pair of transparent elements, such as flat glass elements, with a chamber therebetween. The chamber is filled with electrochromic material that includes a first layer of transparent conductor material and either another layer of transparent conductor (if the mirror subassembly is a fourth surface reflector), or a reflector/electrode (if the mirror subassembly is a third surface reflector). When light is introduced through an opening in the reflector, a primary amount of the light travels through the transparent elements and through the associated layers of electrochromic material without unacceptable distortion. However, a small amount of the light is reflected as the light passes through each of the interfacing surfaces in the mirror subassembly. This can lead to double images (sometimes called “ghosting”), blurred images, shadowing, and/or the occurrence of undesirable scattering of light across a visible face of the mirror subassembly. This is undesirable because it reduces the clarity of the visual display and can, in extreme cases, be interpreted by a customer as a defect. 
     The present invention has been developed in view of the foregoing, and to address other deficiencies of the prior art. 
     SUMMARY OF THE PRESENT INVENTION 
     One aspect of the present invention, a mirror comprises a housing and an electrochromic mirror subassembly in the housing that includes front and rear transparent elements, a layer of electrochromic material associated with the front and rear transparent elements, and a reflector layer associated with the rear transparent element. A portion of the reflector layer defines an opening. An indicia panel covers the opening and an alphanumeric visual display is formed on the indicia panel including a discrete number of preformed letters and symbols. A plurality of light-emitting devices are positioned in the housing to pass light through the indicia panel and the opening of the electrochromic mirror subassembly to selectively illuminate the alphanumeric visual display, with the plurality of light-emitting devices being a number that is equal to or less than the discrete number. 
     Another aspect of the present invention includes a mirror comprising a housing and a mirror subassembly in the housing that includes at least one transparent element and a reflector layer associated with the at least one transparent element. A portion of the reflector layer defines an opening. An indicia panel covering the opening and including an alphanumeric visual display defining a first discrete number of preformed letters and symbols. At least one light source is positioned to pass light through the indicia panel and the opening of the mirror subassembly to selectively illuminate the visual display, with the at least one light source being a second discrete number that is less than or equal to the first discrete number. 
    
    
     These and other features, advantages, and aspects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings. 
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic diagram of a vehicle sensor and display system in accordance with an embodiment of the present invention; 
     FIG. 2 is a front elevational view of a rearview mirror including a passenger air bag status display in accordance with an embodiment of the present invention; 
     FIG. 3 is a partially schematic, side-sectional view illustrating a rearview mirror display in accordance with an embodiment of the present invention; 
     FIG. 4 is a front elevational view of a rearview mirror including a non-planar display in accordance with another embodiment of the present invention; 
     FIG. 5 is a bottom view of the rearview mirror of FIG. 4; 
     FIG. 6 is a side view of the rearview mirror of FIG. 4; 
     FIG. 7 is a front elevational view of a rearview mirror including a non-planar display in accordance with a further embodiment of the present invention; 
     FIG. 8 is a bottom view of the rearview mirror of FIG. 7; 
     FIG. 9 is a front elevational view of a rearview mirror including a non-planar display in accordance with another embodiment of the present invention; 
     FIG. 10 is a top view of the rearview mirror of FIG. 9; 
     FIG. 11 is a front elevational view of a rearview mirror including a non-planar display in accordance with a further embodiment of the present invention; 
     FIG. 12 is a top view of the rearview mirror of FIG. 11; 
     FIG. 13 is a partially schematic, side-sectional view illustrating a rearview mirror display in accordance with an embodiment of the present invention; 
     FIGS. 14 and 15 are front and bottom views of another embodiment of the present invention, including a particularly shaped indicia panel; 
     FIG. 16 is a cross section taken along the line XVI—XVI in FIG. 14; 
     FIGS. 17 and 18 are front and rear exploded perspective views of the mirror shown in FIG. 14; 
     FIG. 19 is a front view of the indicia panel shown in FIG. 14; 
     FIGS. 20 and 21 are rear and side views of the indicia panel shown in FIG. 19; 
     FIG. 22 is a cross section taken along the line XXII—XXII in FIG. 20; 
     FIG. 23 is an exploded perspective view of the indicia panel shown in FIG. 19; 
     FIG. 24 is a flow chart showing a manufacturing method for assembling the mirror shown in FIG. 14; 
     FIG. 25 is a schematic side cross section similar to FIG. 3, but showing undesirable secondary light reflections in the embodiment of FIG. 14; and 
     FIG. 26 is a schematic side cross section similar to FIG. 25, but showing an embodiment where the indicia panel is attached to a front of the mirror subassembly and under the front bezel. 
     FIG. 27 is a cross sectional view similar to FIGS. 16,  25 , and  26 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 is a schematic diagram illustrating a vehicle sensor and display system  1  in accordance with an embodiment of the present invention. The system  1  includes a passenger sensor  2 , a passenger air bag controller  4 , and a passenger air bag status display  6 . Alternatively, the display system could include a manual air bag shutoff switch in place of, or in addition to, the passenger sensor  2  and the air bag controller  4 . 
     The passenger sensor  2  is used to determine whether a passenger is located at a particular position in a vehicle. For example, the passenger sensor  2  may be used to determine whether a passenger is seated in the right front passenger seat of a car or the like. The passenger sensor  2  may be used to determine the approximate size of a passenger in order to allow deactivation of the passenger&#39;s air bag if the passenger is less than a particular size. The sensor  2  may also be used to determine whether an infant or child seat is present and to deactivate the air bag if such an infant or child seat is detected. Examples of suitable passenger sensors  2  include conventional infrared sensors, pressure sensors, and the like. 
     As shown in FIG. 1, the passenger sensor  2  is connected to the passenger air bag controller  4 . Based on the signal provided by the passenger sensor  2 , the controller  4  switches the passenger air bag on when a suitable size person is positioned in the passenger seat, and switches the air bag off when there is no passenger in the seat. Alternatively, the air bag status display  6  may be connected directly to the passenger sensor  2 . Furthermore, the air bag display  6  may be connected to a manual air bag shutoff switch (not shown). The passenger air bag controller  4  is connected to the passenger air bag status display  6 , as schematically shown in FIG.  1 . 
     In accordance with the present invention, the passenger air bag status display  6  is located on a rearview mirror assembly. The display  6  may include any suitable indicia which alerts occupants of the vehicle that the passenger air bag is either active or inactive. For example, the display  6  may illuminate the words “PASSENGER AIR BAG OFF” when the passenger air bag has been deactivated by the controller  4  or by a manual switch. Alternatively, the display  6  may include any other symbols and/or alphanumeric characters, which adequately convey information concerning the status of the passenger air bag to at least one occupant of the vehicle. 
     In accordance with the preferred embodiment of the present invention, the display  6  is located on the interior rearview mirror assembly of a vehicle. Vehicle drivers generally look at the interior rearview mirror very frequently. This frequent use makes the interior rearview mirror an optimal location for the display of critical safety information, such as air bag status. By displaying safety information on the interior rearview mirror assembly, the driver or other occupants of the vehicle may be alerted to critical information, which could otherwise go unnoticed. 
     Examples of suitable displays include LED, vacuum-fluorescent, and LCD displays. The display may comprise a filter with words such as “AIR BAG,” an air bag symbol displayed on a surface which would become visible, more apparent, or change color when the display is illuminated or backlighted, or an indicator light or series of lights in a location relative to a symbol or text indicative of an air bag, which would announce the activation or deactivation of the air bag system by a change of status or color of the light(s). These indicators and displays could be located on the assembly supporting and encasing the mirror, in a module supported by but not integral with the mirror assembly, or in the mirror surface, as more fully described below. 
     FIG. 2 is a front elevational view of a rearview mirror  10  in accordance with an embodiment of the present invention. The rearview mirror  10  includes a mirror surface  11  surrounded by a bezel  12 . In the embodiment shown in FIG. 2, the rearview mirror  10  is an automatic interior electrochromic mirror. However, other types of rearview mirrors including exterior mirrors and prismatic interior mirrors may be provided in accordance with the present invention. 
     As shown in FIG. 2, a chin  13  is located at the bottom of the bezel  12 . A switch  14  may be provided inside the chin  13  in order to turn the automatic electrochromic rearview mirror  10  on or off. A conventional light sensor  15  may be located in the chin  13  or at any other suitable location. In addition, an indicator  16  located in the chin  13  is used to indicate whether the electrochromic rearview mirror  10  is on or off. Typically, the indicator  16  includes a light, which is illuminated when the electrochromic rearview mirror  10  is on. 
     In the embodiment of FIG. 2, a passenger air bag status display  18  is located in the mirror surface  11 . The display  18  includes the words “PASSENGER AIR BAG OFF.” However, any other suitable symbolic or alphanumeric indicia which adequately convey the status of the passenger air bag may be used. 
     In the case of the mirror surface display  18 , any suitable display can be located in or behind the mirror for viewing through the mirror assembly. The display  18  may comprise a substantially transparent section in the mirror. Part or the entire reflective surface may be removed from a selected area. An indicator light source is positioned behind the selected area. Removal of any other opaque elements in the aforementioned area are also desirable so that the indicator or display can be viewed through the mirror. The removal of the reflective surface could create an indicator graphic pattern where desired. For example, the words “PASSENGER AIR BAG OFF” could be etched away from the reflective surface partially or completely to allow transmission of light from a light source through the graphic pattern to thereby indicate the status of the air bag system. 
     FIG. 3 is a partially schematic side sectional view showing one type of rearview mirror display assembly  20  that may be used in the rearview mirror  11  of FIG.  2 . The rearview mirror display assembly  20  includes a first glass sheet  21  which forms a viewing surface facing the occupant of a vehicle. The viewing surface of the first glass sheet  21  may be smooth or may be provided with a matte texture. A second glass sheet  22  is spaced from the first glass sheet  21 . A substantially transparent, electrically conductive layer  23  covers the interior side of the first glass sheet  21 , while another substantially transparent, electrically conductive layer  24  covers the interior of the second glass sheet  22 . An electrochromic composition  25  fills the gap between the glass sheets  21  and  22 . A reflective layer  26  made of any suitable material, such as silver, is provided on the surface of the second glass sheet  22 . The display assembly  20  is thus provided as a part of an electrochromic rearview mirror. The various components of the electrochromic rearview mirror may be arranged and constructed as disclosed in the previously cited U.S. patents incorporated herein by reference. 
     As shown in FIG. 3, a portion of the reflective layer  26  is removed from the glass sheet  22  in order to provide an opening  27 . An indicia panel  28  covers the opening  27 . A light source  29  is arranged such that upon illumination, light travels through the indicia panel  28 , opening  27 , and the remaining layers  21 - 25  of the electrochromic mirror assembly toward the occupant of the vehicle. The indicia panel  28  may be unmarked or may comprise any desired indicia, such as alphanumeric symbols or the like. The indicia panel  28  may optionally comprise a color filter. The light source  29  may comprise any suitable type of illuminator, such as an LED, LCD, vacuum-fluorescent element, incandescent light, or the like. 
     The display  18  may thus be part of the silver coating that is etched/removed to form the individual letters or components of the graphics through which the light would pass to illuminate the lettering or graphics. The display  18  may further comprise lettering or graphics printed or otherwise applied to a cleared area in the silver where the graphics or lettering would be of a design to show contrast when illuminated. The graphics or display can be separate from the mirror element mounted behind the element, such as a conventional LCD display, a vacuum-fluorescent display, a static mask through which light will pass to display graphics or lettering, or other display types. 
     A color filter may optionally be included between the display light source and the viewer, such as a color filter printed or bonded to the mirror surface, or a filter installed on the light source, or at any point therebetween. The light source could also be of a bandwidth narrower than full-spectrum visible light for the purpose of displaying a distinctive color through the display graphics to indicate the status of the air bag system. 
     In versions requiring removal of some of the silver surface, a portion rather than all of the silver can be removed in an area and still allow the display to be seen. One method is to remove a pattern, such as a grid. This allows conduction across a substantial amount of the surface facilitating coloring and clearing of the electrochromic substance in that area proportional to the rest of the element. Another method is to allow breaks in letters and graphics to avoid closed islands in the surface. 
     In the embodiment of FIG. 2, the surface of the display  18  is flush with the surface of the mirror  11 . Alternatively, the surface of the display  18  may be non-planar. For example, the surface of the display  18  may comprise a convex arc extending from the surface of the mirror  11 . 
     In accordance with a preferred embodiment of the present invention, a non-planar display is provided on a rearview mirror assembly. As used herein, the term “non-planar display” means a display having a contoured exterior viewing surface instead of a flat exterior surface. Preferred non-planar contoured display surfaces include curved or faceted convex configurations. 
     FIGS. 4-6 illustrate a rearview mirror  30  having a non-planar display in accordance with a preferred embodiment of the present invention. The rearview mirror  30  is an automatic electrochromic mirror including a mirror surface  31  and a bezel  32 . Although an electrochromic mirror is shown in FIGS. 4-6, other types of mirrors, such as prismatic rearview mirrors, are within the scope of the present invention. A contoured chin  33  having a curved front face is located at the bottom of the bezel  32 . The contoured chin  33  houses a compass switch  34 , a mirror switch  35 , a light sensor  36 , and an on/off indicator  37 . In this embodiment, a non-planar display  38  is located in the chin  33 . As shown most clearly in FIG. 5, the surface of the non-planar display  38  is convex and conforms to the contoured surface of the chin  33 . 
     The use of a convex non-planar display  38  provides substantially improved viewability of the information provided by the display. The curved exterior surface of the display  38  essentially prevents unwanted glare from surrounding light sources and provides improved viewability to occupants of the vehicle. For example, both the driver and front passenger(s) of the vehicle can readily see the information provided by the display  38  without obstruction. In a preferred embodiment, the non-planar surface of the display  38  has a matte texture in order to further reduce unwanted glare. 
     A display, such as a vacuum-fluorescent, LCD, LED, or the like, may be mounted in the bezel or, preferably, behind a filter in the bezel. A static display may simply be illuminated or the illumination color changed to display information. This display offers several possible configurations. A preferred display comprises an opening in the bezel and a mask or label with graphics and/or lettering printed onto the surface to allow light to pass through the lettering or graphics portion of the label. Lettering or graphics molded or embossed into the bezel through which light could pass to illuminate the lettering or graphics may be used. A translucent bezel or portion of the bezel on which the graphics could be painted or printed to allow light to pass through only select parts may also be used. Furthermore, printed or molded graphics or lettering with a corresponding translucent or open section through which light could pass to indicate status may be used. In addition, a status display of graphics and/or lettering with a corresponding light which illuminates or changes color may be used. 
     In the embodiment shown in FIGS. 4-6, the rearview mirror  30  includes a compass reading  39 , which indicates the direction in which the vehicle is oriented. The compass switch  34  may be used to turn the compass reading  39  on and off. As shown most clearly in FIGS. 5 and 6, the rearview mirror  30  includes a housing  41  and a conventional mounting bracket  42 . However, other mounting methods can be used. 
     FIGS. 7 and 8 illustrate a rearview mirror  50  in accordance with another embodiment of the present invention. The electrochromic rearview mirror  50  includes a mirror surface  51  and a surrounding bezel  52 . A chin  53  having a generally planar front face extends from the bottom of the bezel  52 . The chin  53  houses a compass switch  54 , a mirror switch  55 , a light sensor  56 , and an on/off indicator  57 . A convex non-planar display  58  extends from the surface of the chin  53 . A compass display window  59  is provided in the mirror surface  51 . The rearview mirror  51  also includes a housing  61 . The convex surface of the non-planar display  58  shown in FIGS. 7 and 8 substantially improves visibility of the displayed message. 
     FIGS. 9 and 10 illustrate a rearview mirror  70  in accordance with a further embodiment of the present invention. The electrochromic rearview mirror  70  includes a mirror surface  71  surrounded by a bezel  72 . A chin  73  located at the bottom of the bezel  72  includes a mirror switch  74 , a light sensor  75 , and an on/off mirror indicator  76 . A crown  77  having a substantially planar front surface is located at the top of the bezel  72 . A convex non-planar display  78  is located in the crown  77 . The rearview mirror  70  also includes a housing  81 . 
     FIGS. 11 and 12 illustrate another rearview mirror  90  in accordance with a further embodiment of the present invention. The rearview mirror  90  includes a mirror surface  91  surrounded by a bezel  92 . A chin  93  located at the bottom of the bezel  92  houses a mirror switch  94 , a light sensor  95 , and an on/off mirror indicator  96 . The right side of the bezel  92  includes an extension  97  having a non-planar display  98  therein. The rearview mirror  90  comprises a housing  99 . In this embodiment, the non-planar display  98  is oriented such that a passenger seated in the front right seat of a vehicle can easily see whether the passenger air bag is on or off. 
     FIG. 13 is a partially schematic side sectional view illustrating a rearview mirror non-planar display assembly  100  in accordance with an embodiment of the present invention. The non-planar display assembly  100  includes an electrochromic mirror assembly comprising a first glass sheet  101 , a second glass sheet  102  spaced from the first glass sheet  101 , and an electrochromic material  103  filling the gap between the glass sheets  101  and  102 . A seal  104  extends between the glass sheets  101  and  102  in order to retain the electrochromic material  103  therebetween. Although not shown in FIG. 13, the electrochromic mirror assembly may include substantially transparent electrically conductive films on the interior surfaces of the glass sheets  101  and  102 , and may comprise a reflective mirror surface positioned at any suitable location, such as the exterior surface of the second glass sheet  102 . Suitable types of electrochromic rearview mirror assemblies are disclosed in the previously cited U.S. patents which are incorporated herein by reference. 
     As shown in FIG. 13, a bezel  105  contacts the exterior viewing surface of the first glass sheet  101  of the electrochromic mirror assembly. A lamp holder  106  having a reflective interior surface is formed in the bezel  105 . A light source assembly  107  is secured in the lamp holder  106 . In the embodiment shown in FIG. 13, an LED  108  is provided as part of the light source assembly  107 . Alternatively, any other suitable light source, such as an electroluminescent source, incandescent light, or the like, may be used. An indicia panel  109  covers the lamp holder  106 . The indicia panel  109  forms the exterior viewing surface of the display. In accordance with the preferred embodiment of the present invention, the indicia panel  109  comprises a convex exterior viewing surface defined by at least one radius of curvature, as more fully described below. 
     The indicia panel  109  shown in FIG. 13 may be unmarked or may comprise any desired graphics, alphanumeric symbols, or the like. The indicia panel  109  may optionally include a color filter. 
     Preferred non-planar displays of the present invention comprise a convex exterior viewing surface defined by at least one radius of curvature. The radius of curvature may be constant or may vary along the exterior surface of the display. For example, in the embodiments shown in FIGS. 4-10, the non-planar displays have an exterior curved surface of substantially constant radius defined by an arc swept around a substantially vertical axis. Such arcs are most readily seen in FIG. 8, element  58  and in FIG. 10, element  78 . The radius of the typically ranges from about 1 cm to about 60 cm, and more preferably from about 1.5 cm to about 15 cm. This geometry results in a display that is readily viewed by all occupants of the vehicle while reducing unwanted glare. 
     In the embodiments of FIGS. 11 and 12, the non-planar display has a varying radius of curvature, which substantially conforms to the curved bezel surface of the mirror. The non-planar display reduces glare and is readily viewable to at least the right front passenger of the vehicle. 
     Conventional planar displays have a high degree of first surface reflection, which decreases the contrast between the graphics of the display which are intended to be viewed and the reflected light from the surface. This degrades the ability for a passenger to view the displayed information, since the front seat passenger is usually seated in a position which can create a viewing angle up to 30 degrees or more off of perpendicular to the mirror front surface. A non-planar display, as well as surface treatment such as a matte finish to decrease the reflection of the surface, increases the contrast of the display, especially when viewed at an angle. The curvature of the display also serves to orient the display or a portion of the display toward the passenger and, therefore, improve the visibility of the display. A low-glare surface and a convex surface have the added benefit of reducing glare on the display surface for the driver and other occupants of the vehicle. Additionally, since the display surface is typically at the same angle as the mirror surface, glare from the headlamps of a following vehicle can also render a glossy, planar display unreadable. 
     Although the non-planar displays described in the specific embodiments herein are used to convey information concerning the status of a passenger air bag, other types of symbolic or alphanumeric information may be displayed on rearview mirror assemblies in accordance with the present invention. For example, the status of other air bags or supplemental restraint systems in the vehicle may be displayed. Furthermore, information such as door ajar, fasten seat belts, fuel mileage, time, temperature, heading, altitude, and the like may be displayed. 
     MODIFICATION 
     A mirror assembly  115  (also referred to herein as “mirror  115 ” herein) (FIGS. 14 and 15) includes a housing  116  and a bezel  117  defining a cavity  118 , and further includes an electrochromic mirror subassembly  120  (FIG. 25) supported in the cavity  118  along with a printed circuit board  119 . The printed circuit board  119  has a circuit thereon that is configured to operate the electrochromic mirror subassembly  120  for controlled darkening to reduce glare in the mirror  115 . An indicia panel  130  (sometimes called an “applique”) is attached to a rear of the mirror subassembly  120  or bezel  117  to provide a low cost, highly attractive lighted display on the mirror  115 . The indicia panel  130  is constructed to be exceptionally attractive and effective, as described below. The indicia panel  130  is constructed with locator-engaging details that facilitate its alignment on the mirror subassembly  120 , and further that provide alignment of the mirror subassembly  120  on the bezel  117  and in the housing  116 , as also disclosed below. 
     The illustrated electrochromic mirror subassembly  120  is commonly referred to as a fourth surface reflector, but it is contemplated that the present invention will work well with third surface reflectors and with other mirror constructions. Accordingly, it is contemplated that a scope of the present invention includes all such mirror constructions and the present description should not be construed as unnecessarily limiting. The illustrated mirror subassembly  120  (FIG. 25) includes front and rear transparent elements  121  and  122  (e.g., glass), electrically conductive layers  123  and  124  on inner surfaces of the transparent elements  121  and  122 , respectively, a layer of electrochromic material  125  located between the conductive layers  123  and  124 , and a reflective layer  126  on a rear surface of the rear transparent element  122  (i.e., the “fourth” surface of the mirror subassembly  120 ). A seal  125 ′ extends around an inside perimeter of the transparent elements  121  and  122  to retain the electrochromic material  125 , when the electrochromic material  125  is a liquid-phase type, or gel-phase type, or a hybrid of same. (It is noted that a perimeter edge striping may be applied to transparent elements  121  and  122  for aesthetics, which results in a similar appearance.) A portion of the reflective layer  126  is etched away or otherwise removed to define an elongated opening  127  (FIG.  18 ). The indicia panel  130  is adhered to the reflector layer  126  in a location  131 ′ where it covers the opening  127 . Light sources  129  are positioned behind the indicia panel  130  to pass light through the indicia panel  130  and through the opening  127  of the electrochromic mirror subassembly  120  to selectively illuminate detailed symbols and information on the indicia panel  130  for viewing by a vehicle driver or passengers. A foam light seal  134  on the indicia panel  130  is located between the printed circuit board  119  and the indicia panel  130 , and is shaped (see FIG. 16) to sealingly engage the printed circuit board  119  and the indicia panel  130  to prevent light leakage around the indicia panel  130 . Specifically, the foam light seal  134  defines multiple windows  146 ′- 148 ′ (FIG. 23) engaging the indicia panel  130  for containing light from each of the light sources  129  (FIG. 17) as each window area is illuminated. The housing  116  and the bezel  117  snap together and are shaped to compress together the mirror subassembly  120 , the indicia panel  130 , the printed circuit board  119 , and the light seal  134 , thus compressing the light seal  134  to assure good contact by the light seal  134 . 
     It is contemplated that the present invention includes many different indicia panels constructed with light-absorbing material to absorb undesired stray light and reflections, and also constructed with locator tabs and locator features. The illustrated indicia panel  130  (FIG. 23) includes a body panel  140  of light-passing translucent or transparent material, such as a mylar sheet, having a rectangular main section  141  and down-angled tabs  142  at each end. The body panel  140  includes a front surface treated to minimize the degree to which it will show fingerprints, as known in the art. A locating feature or locator hole  143  is formed in each tab  142 . The holes  143  are configured to engage locator protrusions on a fixture (not specifically shown, but see FIG. 23) for providing very accurate alignment of the indicia panel  130  on the mirror subassembly  120  when the indicia panel  130  is adhered to a rear surface of the mirror subassembly  120 . The locator holes  143  are further configured to engage a pair of locator protrusions  170  on the bezel  117  to very accurately locate the mirror subassembly  120  (including the indicia panel  130 ) in the bezel  117  and mirror housing  116 , as described below. When adhesive layer  155  is eliminated, the locator holes engage the protrusions  170  for alignment of the indicia panel  130 , while other structure on the housing  116  and bezel  117  align the mirror subassembly  120 . 
     A light-absorbing layer  145  of ink, film, paint, or the like is applied to a back surface of the body panel  140 . The light-absorbing layer  145  accurately forms relatively small and well-defined windows  146 - 148  on the body panel  140 . One or more layers of semitransparent or translucent material  149 - 153  are applied onto the body panel  140  in the area of windows  146 - 148  to form the indicia of the present visual display. It is contemplated that the materials  149 - 153  have properties allowing them to be accurately applied to form detailed symbols, known printing and symbol forming, film applying processes. For example, it is contemplated that the ink could be applied by a multi-coating printing process, or even by an ink-jet printer or copying/duplicating machine. The illustrated black material  149  includes apertures that form clear lettering. The layer  150  is applied behind the clear lettering and is translucent white, such that the words “PASSENGER AIR BAG” appear when the window  146  is luminated. The material  151  is also white and shows through as a symbol of a person with an air bag inflated in front of the person, but it is contemplated that the material  151  could of course be colored (e.g., orange or red) to highlight and distinguish the symbol. The materials  152  and  153  form letters for the words “on” and “off,” which are visible only when the individual window  147  or window  148  are luminated. 
     In the illustrated indicia panel  130 , an elongated layer  155  (FIG. 23) of adhesive having a small vertical dimension is applied to a face of the body panel  140  along an upper edge above the windows  146 - 148 , with ends of the layer  155  extending partially downwardly along an upper edge of the down-angled tabs  142  to form a concavely shaped adhering area on three sides of the indicia forming the visible display. This concave arrangement helps avoid trapping air when adhering the indicia panel  130  to the mirror subassembly  120 . It also helps reduce thermal expansion problems by providing an area in which the body panel  140  can expand or flex. The adhesive layer  155  is covered with a release paper  156  to protect the adhesive during shipping and handling prior to assembly. 
     Seal  134  (FIG. 23) includes a piece of compressible foam  157  and further includes an adhesive-covered face  158  that adheringly attaches to a back of the light-absorbing layer  145  on the body panel  140  of the indicia panel  130 . The compressible foam  157  has windows  146 ′- 148 ′ cut into the foam that align with the windows  146 - 148  in the light-absorbing layer  145 . 
     The bezel  117  (FIGS. 17 and 18) is generally oval shaped and configured to surround and mateably receivingly engage a perimeter of the mirror subassembly  120 . A lower horizontal section (FIG. 16) of the bezel  117  includes upper and lower portions  161  and  162  that form a window for receiving finger-actuable switches or buttons  160  on the mirror  115 . That portion of the bezel  117  that engages the perimeter of the mirror subassembly  120  includes a rearwardly extending inside section  163  that engages a face of the front transparent element  121 , an aesthetically shaped front or transition area  164 , and a rearwardly extending outer side section  165  that extends at least to a position adjacent an edge of the mirror subassembly  120 . That portion of the bezel  117  that engages the housing  116  includes a rearwardly extending leg or flange  166  defining an outwardly facing cavity  167 . The housing  116  includes a forwardly extending section  168  that fits into the cavity  167  and overlappingly engages the leg  166 . The bezel  117  includes a hook-shaped connector  169  (FIG. 17) that is constructed to frictionally snap attach into a recess  169 ′ in the housing  116 . Guide fingers  169 ″ extend from housing  116  at locations adjacent the hook-shaped connectors  169 . The fingers  169 ″ are shaped to engage a back surface of the flange  166  in a manner that forces the hook-shaped connector  169  into secure engagement with the recess  169 ′. It is contemplated that the hook-shaped connector  169  and the recess  169 ′ can be reversed on the housing  116  and the bezel  117 , or that they can be replaced with other connection means, such as screws, mechanical fasteners, adhesive, sonic welding, and the like. 
     FIG. 27 shows a condition that occurs during daylight. As discussed below, an optimal arrangement occurs for viewing/reading the alphanumeric information when a color of the indicia panel  130  is the same as the color of the light from the light source  129 . In particular, amber color has been shown to result in an optimal brightness and distinctiveness of the alphanumeric image that is exceptionally readable, even at reduced power of the light source  129 , as discussed below. 
     The eye sees both ambient reflected light L R  and transmitted light L T  from the desired amber light source according to the following formula: 
     
       
         
           L 
           E 
           =L 
           R 
           +L 
           T 
         
       
     
     (Where L E =Total light entering eye; L R =Reflected light; and L T =Transmitted light) 
     L T =a constant such as about 500 to 900 cd/m 2    
     as L R  approaches infinity, then L E =L R    
     Therefore, the brighter the ambient light, the more the eye reads the color of the printing as opposed to the color of the transmitted light. Also, as the ambient reflected light L R  increases, and if the alphanumeric information, symbols, and printing are white (i.e. different than the transmitted light), hot spots tend to be accentuated. This is because the eye starts to see more reflected light L R  at some points on the indicia and more transmitted light L T  at the hot spots. If the color of the reflected light is matched to the transmitted light, then the eye sees transmitted and/or reflected light as looking the same. Therefore, “hot spots” tend to be less noticeable or eliminated. A further benefit has been found in that amber light having an L T  of 500-900 cd/m 2  is visible and readable in the daytime. Where a current design calls for white printing, the customer usually requires the transmitted light to be at least 500-900 cd/m 2 , so that L T  is much greater than L R  for most daytime driving conditions. As it turns out, very bright sunny days can cause L R  to be 1400+cd/m 2 , which is significant and potentially overwhelming to the eye relative to L T  even at 500-900 cd/m 2 . 
     Testing has shown that nighttime L E  needs to be in the range of 5 to 20 cd/m 2  (at night, L R  0 so L E =L T ). 
     In the current design, it is difficult to provide a large dynamic range. Dynamic range is a ratio of daytime to nighttime brightness used herein to mathematically represent the range of brightness of the alphanumeric information that is generated. The following formula represents, by example, a desired dynamic range where L E  daytime=500 cd/M 2 :              L   E                   daytime         L   E                   nighttime       =         500                 cd        /          m   2         5                 cd        /          m   2         =     100   :     1                 dynamic                 range                                
     At 500 cd/m 2  daytime, 20 cd/m 2  is about as low as you can get at night with simple electronics. This results in a dynamic range as follows:              L   E                   daytime         L   E                   nighttime       =       500   20     =     25   :     1                 dynamic                 range                                
     If you desire 5 cd/m 2  at night with 25:1 dynamic range and with simple electronics, since 5 cd/m 2 ×25=125 cd/m 2 , this would result in a daytime light L T  of 125 cd/m 2  daytime. At L T =125 cd/m 2  daytime, L R  quickly overpowers L T  and you get an undesirable appearance or “wash-out” of the alphanumeric information on the indicia panel  130 . 
     However, due to the constant color and constant contrast of the color (e.g. amber) to the rest of the indicia panel  130 , if the printing color of layer  150  is matched to the transmitted color of the light source  129 , you can use much less transmitted light during the day and produce the following benefits: Lower power usage by as much as about 30% to 50%; wider angle output LED&#39;s, improving light spreading or evenness; lower nighttime L T  using simple electronics; lower cost or fewer LED&#39;s; and improved (consistent) appearance of information regardless of ambient light levels. 
     These benefits are believed to be surprising and unexpected, and are a direct result of matching the color of the diffuser  150  and/or the indicia panel  130  with the color of the light from light source  129 . This “color-matched” arrangement is believed to be inventive, novel, and non-obvious over known prior art. 
     The bezel  117  (FIG. 18) includes a pair of rearwardly protruding locator protrusions  170  spaced on either side of the indicia panel  130 . The protrusions  170  are shaped to engage the holes  143  on the tabs  142  to accurately locate the indicia panel  130  relative to the bezel  117 . This is very important because the indicia (i.e., the lettering and symbols) on the indicia panel  130  must be very accurately aligned with the bezel  117  to avoid the appearance of misalignment and poor quality. Since the indicia panel  130  is accurately adhered to the mirror subassembly  120 , the protrusions  170  cause the mirror subassembly  120  (including the visible interior of the seal  134 ) to also be accurately aligned with the bezel  117 . 
     Notably, it is specifically contemplated that adhesive layer  155  can be eliminated. In such case, the protrusions  170  accurately locate the indicia panel  130 , while ribs and other structure of the housing  116  and bezel  117  accurately locate the mirror subassembly  120 . 
     The printed circuit board  119  (FIG. 18) includes locator apertures or holes  173  that also engage the protrusions  170  to accurately locate the printed circuit board  119 . The illustrated light sources  129 , which can be any suitable type of illuminator, such as LED, LCD, vacuum-fluorescent elements, incandescent lights, or the like, are mounted to the printed circuit board  119 . Nonetheless, it is contemplated that the light sources  129  could be mounted behind the printed circuit board  119  and shine through windows in the printed circuit board  119 . Switches  160  are also mounted to the printed circuit board  119  in a position where they align with lower windows in the bezel  117 , and where they are easy to operate by a seated driver. 
     The housing  116  (FIG. 17) includes sidewalls  176  having the recesses  169 ′ and guide fingers  169 ″ that receive the hook-shaped connectors  169 , and further include a back wall  177 . The back wall  177  includes mounting structure  178  for operably adjustably engaging the vehicle ball mount  179  (FIG.  15 ). Projections  180  (FIG. 16) extend forwardly from the back wall  177  into abutting engagement with the printed circuit board  119 . When assembled, the bezel  117  snap attaches to the housing  116  to compress together the mirror subassembly  120 , the indicia panel  130 , the printed circuit board  119 , and the light seal  134  in a compressed sandwich-like arrangement, with the light seal  134  lightly compressed. 
     As shown by FIG. 24, the method of assembly includes printing and forming the indicia panel  130  in a step  183 , and then adhering the foam light seal  134  to the indicia panel  130  in a step  184 . In a step  185 , the mirror subassembly  120  is fixtured by fixtured engagement of its locator holes  143 , and the indicia panel  130  is accurately attached to the mirror subassembly  120  (if adhesive is used) by removing the release paper  156  and by adhering the adhesive  155  to a rear surface of the rear transparent element  122  as the indicia panel  130  is accurately held. The indicia panel  130  is then used to accurately locate the mirror subassembly  120  to the bezel  117  by registering the holes  143  on the protrusions  170  of the bezel  117  in a step  186 . Alternatively, where adhesive layer  155  is eliminated, protrusions  170  engage holes  143  to locate the indicia panel  130 , but the mirror subassembly  120  is located by engagement with the bezel  117  and housing  116 . The printed circuit board  119  is also accurately located by registering its holes  173  on the protrusions  170  in a step  187 . The housing  116  is snap attached to the bezel  117  in step  188 . This causes the abutting projections  180  on the housing  116  to engage the printed circuit board  119 , compressing the foam light seal  134  between the printed circuit board  119  and the indicia panel  130 , and compressing the indicia panel  130  with light pressure against the mirror subassembly  120 . This light pressure helps hold the indicia panel  130  against the mirror subassembly  120 , yet permits dimensional variation during assembly. This arrangement also allows the expansion and contraction that occurs during thermal cycling of the mirror  115  while in service. 
     One important benefit of using a light-absorbing indicia panel  130  is shown in FIG.  25 . The light source  129  emits light  190 , a primary portion  191  of which travels through the indicia panel  130 , through the opening  127 , and out through various components of the mirror subassembly  120  to a viewing person. Secondary reflections  192 - 196  occur at a rear surface of the rear transparent element  122 , and at each interface between the layers  122 / 124 ,  124 / 125 ,  125 / 123 , and  123 / 121 . These secondary reflections  192 - 196  are absorbed by the light-absorbing layer  145  on the indicia panel  130 . This arrangement greatly reduces unwanted stray light. The size of each window  146 - 148  and windows  146 ′- 148 ′ (see FIGS. 16-18 and  23 ), and also the size of the opening  127  (FIG.  25 ), are chosen to optimize the clarity of the image projected by primary light portion  191  without detracting from the reflected images of the mirror  115 . In a preferred form, the vertical dimension of the letters and symbols is about 25 percent to about 75 percent, or more preferably about 50 percent, of the vertical dimension of the opening  127 . 
     It is noted that mirror subassemblies  120  having the same size opening  127  can be used in mirrors  115  having different options. For example, a different indicia panel  130  can be used along with different printed circuits boards  119 , while still using the same bezel  117 , housing  116 , and mirror subassembly  120 . This greatly facilitates manufacturing high volumes of mirror subassemblies  120  while still allowing for a maximum of options. Further, the same housing  116  and mirror subassembly  120  can be used, while using a different bezel  117 . This is an important advantage since the mirror subassembly  120  is one of the more expensive components of the mirror  115 . It is important to have the mirror subassembly  120  be at a higher volume to optimize automation of the manufacturing process and to minimize costs. 
     It is specifically contemplated that aspects of the present invention can be utilized advantageously in different mirror constructions. One such mirror is illustrated in FIG. 26, and includes a front-mounted indicia panel  130 A adheringly attached to a front surface of the front transparent element  121 A. In mirror  11 SA, components and features that are identical or similar to the features and components of mirror  115  are identified by the same number. 
     In mirror  115 A, the indicia panel  130 A is adhered to the front surface using adhesive  155 A, and the light-absorbing layer  145 A is located adjacent the adhesive  155 A. Notably, it is contemplated that the adhesive  155 A could be omitted where the indicia panel  130 A is adequately supported by portions of the bezel  117 A. It is also contemplated that the light-absorbing layer  145 A could be positioned on the other side of the indicia panel  130 A or even on any of the front or rear surfaces of the transparent elements  121 A and  122 A. The indicia panel  130 A provides many of the advantages noted above, including fixturing advantages, good appearance, low cost, and a flexible part that can be used in mirrors having different options. 
     In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.