Auto dimming mirror

[Tonester]

Just curious. How does the auto dimming rear view mirror actually work. There is a sensor front and back but does anyone know the principle behind how it works??

[dissin]

Just curious. How does the auto dimming rear view mirror actually work. There is a sensor front and back but does anyone know the principle behind how it works??

From my memory the front sensor knows when its night ie dark, and compares light received via rear sensor and dims the glare accordingly

[junebug1701]

Just curious. How does the auto dimming rear view mirror actually work. There is a sensor front and back but does anyone know the principle behind how it works??

My RAV4 came with one of these and I had never even seen one before. I must admit, it works very well. Here's the explanation from the Gentex site:

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Gentex uses its proprietary, solution-phase electrochromic technology. We sandwich an electrochromic gel between two pieces of glass, each of which has been treated with a transparent, electrically conductive coating, and one with a reflector.

1. A forward-facing sensor recognizes low ambient light levels and signals the mirror to begin looking for glare.

2. A rearward-facing sensor then detects glare from the vehicles traveling behind you, sending voltage to the mirror's EC gel in proportion to the amount of glare detected.

3. The mirror dims in proportion to the glare and then clears when the glare is no longer detected.

4. The interior mirror's sensors and electronics control the dimming of both interior and exterior mirrors.

http://www.gentex.com/auto_how_nvs_work.html