AKA Automatic Dimming Rearview Mirror

DESCRIPTION
Electrochromic day/night rearview mirror automatically
changes reflectance to reduce glare from headlights. At night, as
glare of headlights from behind increases, mirror will gradually
become darker to absorb glare. During daylight or when gearshift lever
is in Reverse, mirror will be clear and fully reflective. On some
models, driver’* side outside mirror will also be an electrochromic
day/night mirror that is controlled by inside mirror. On some models,
inside rearview mirrors also include a compass.
OPERATION
Day/night mirror(*) use a thin layer of electrochromic
material between 2 plates of conductive glass. Two photocell sensors
signal levels of light to a logic circuit. A forward-facing photocell
sensor measures ambient light levels. A rear-facing photocell sensor
measures glare from approaching vehicle headlights. When logic circuit
senses more light from the headlight sensor than the ambient light
sensor, the electrochromic drive circuit applies voltage to mirror(*).
Approximately 1.15 volts is applied to mirror(*) when a large amount
of glare is present, causing mirror(*) to darken. Voltage will be
reduced to 0.01 volt when both photocells indicate the same light
level.
When gearshift lever is shifted into Reverse, battery voltage
is applied to mirror reset terminal. Mirror will gradually change to a
clear state for better vision when backing up.