Gentex Corporation (NASDAQ: GNTX) manufactures automatic-dimming rear-view mirrors and camera-based driver assistance systems for the global automotive industry. The company also provides commercial smoke detectors and signaling devices to the North American fire protection market, as well as dimmable aircraft windows for the commercial, business and general aviation markets. The company is based in Zeeland, Michigan and was founded in 1974. Their mirrors use electrochromism to dim in proportion to the amount of light reaching them from following vehicles' headlamps. The mirrors are available with added electronic features. About 98 percent of the company's net sales are derived from the sale of auto-dimming mirrors to every major automaker in the world.

Gentex was founded in 1974 by Fred Bauer as a manufacturer of fire protection products. The company created the first dual-sensor photoelectric smoke detector, considered to be less prone to false alarms, while still quickly detecting smoldering fires. In the early 1990s, Gentex introduced a smoke detector equipped with a strobe light designed to alert the deaf and hard of hearing individuals. Today, Gentex manufactures a complete line of photoelectric detectors for fire alarm systems, standalone, and interconnect systems. Gentex also manufactures its Commander series horn/strobes, along with other notification appliances including speaker/strobes, mini-horns, bells, and weatherproof devices.

Gentex first introduced a rear-view mirror that automatically adjusted to glare conditions in 1982.

Gentex introduced an automatic dimming mirror based on electrochromism in 1987. The reduction of glare eliminates the temporary blind spot caused by the Troxler effect after the glare source leaves the field of view.

These mirrors have forward- and rearward-facing sensors to measure the ambient light level and glare of approaching vehicles, respectively. An electrochromic gel is placed between two pieces of glass, which allows the mirror to dim in proportion to the glare level.

In 1991, exterior electrochromic mirrors were added to the Gentex product line. These mirrors operate on the same principle as the interior mirrors. Different mirror geometries were added in 1997 to accomplish various tasks, such as eliminating blind spots and offering an expanded field of view.

Gentex signed a contract through PPG Aerospace to deliver automatic dimming windows for the Boeing 787 Dreamliner. These windows will use electrochromics to adjust the amount of light allowed through the window.