Automotive rearview mirrors have numerous attributes that render them desirable hosts for a variety of added features beyond their principal function of providing a rearview field of vision. One attribute is location. The driver frequently looks at rearview mirrors as part of the normal driving task, and thus they are ideal locations for information display such as of directional information from a compass sensor and/or of temperature information from an exterior temperature sensor. Icons and indicia displaying status of, for example, passenger airbag enable/disable, are readily viewable by the driver when displayed at an interior rearview mirror or exterior sideview mirror. Rearview mirrors are desirable locations for automatic wiper activation rain sensors, automatic headlamp activation controllers, remote keyless entry receivers, garage door opener/home access transmitters, and antennae such as for global positioning satellite (GPS) systems. Mirrors are also excellent locations for lights such as map reading lights incorporated in interior mirror assemblies and ground illumination security lights located in exterior mirrors assemblies.
Another attribute is electrical service. Many interior and most exterior mirrors are electrically powered. For example, electrochromic mirrors that electrically dim in reflectivity when glaring conditions are detected are today commonplace. The circuitry to control the electrochromic dimming function and any other mirror-mounted electronic feature can be commonly housed in or on a rearview mirror assembly, and wholly or partially share components on a common circuit board.
A third attribute is flexibility. By hosting an added feature within a rearview mirror assembly, an automaker has wide latitude in option packaging. As car area networks (CAN) proliferate, the ease and convenience of incorporation of added features will be even further enhanced. Car area networks can provide a plug-and-play opportunity for incorporation of added feature functions whereby mirror mounted features such as, for example, a pyroelectric intrusion detector can output a signal to the CAN when a cabin intrusion is detected, that is received and reacted to by an alarm system elsewhere on the network.
This paper reviews added feature interior and exterior rearview mirrors, and outlines how they can enhance consumer safety, convenience and affordability.