Rear-view mirror

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Rear-view mirror showing cars parked behind the vehicle containing the mirror
Triple mirror in a Irizar Eurorider bus

A rear-view mirror (or sometimes, rear-vision mirror in British English) is a mirror in automobiles and other vehicles, designed to allow the driver to see rearward through the vehicle's backlight (rear windscreen).

Usually, the rear-view mirror is affixed to the top of the windscreen on a swivel mount allowing it to be freely rotated. In the past, some cars had the rear-view mirror mounted on top of the dashboard. Rear-view mirrors are designed to break away to minimize injury to occupants who may be thrown against it in a collision.

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[edit] History

Ray Harroun's Marmon "Wasp" with its rear-view mirror mounted on struts above the car on display in the Indianapolis Motor Speedway Hall of Fame Museum.

The rear-view mirror's earliest known use and mention is by Dorothy Levitt in her 1906 book The Woman and the Car which noted that women should "carry a little hand-mirror in a convenient place when driving" so they may "hold the mirror aloft from time to time in order to see behind while driving in traffic", thereby inventing the rear view mirror before it was introduced by manufacturers in 1914.[1] The earliest known rear-view mirror mounted on a motor vehicle appeared in Ray Harroun's Marmon racecar at the inaugural Indianapolis 500 race in 1911.[2] Although Harroun's is the first known use of such a mirror on a motor vehicle, Harroun himself claimed he got the idea from seeing a mirror used for the same purpose on a horse-drawn vehicle in 1904.[3]

Elmer Berger, is usually credited with inventing the rear-view mirror, though in fact he was the first develop it for incorporation into production streetgoing automobiles.[citation needed]

[edit] Augmentations and alternatives

Rear-view mirrors are usually augmented with side-view mirrors on the driver's and/or passenger's side of the vehicle.

Recently, rear-view video cameras have been built into many new model cars, such as the Mazda Hakaze Concept. This was partially in response to the rear-view mirrors' inability to show the road directly behind the car, due to the rear deck or trunk obscuring as much as 3–5 metres (10–15 feet) of road behind the car. For example, as many as 50 times a year, small children are killed by SUVs in America because the driver cannot see them in their rear-view mirrors [4]. These camera systems are usually mounted to the bumper or lower parts of the car allowing for better rear visibility.

Aftermarket secondary rear-view mirrors are available. They attach to the main rear-view mirror and are independently adjustable to view the back seat. This is useful to parents to monitor their children in the backseat.

[edit] Dimming

Glare from a following vehicle's headlamps in a rear view mirror

A prismatic rear-view mirror can be tilted to reduce the brightness and glare of lights, mostly for headlights shining directly on the eye level at night. This manual tilt mirror is made of a piece of glass that is wedge-shaped in cross section—its front and rear surfaces are not parallel. In the day view position, the front surface is tilted and the reflective back side gives a strong reflection. When the mirror is moved to the night view position, its reflectorized rear surface is tilted out of line with the driver's view. This view is actually a reflection off the non-reflectorized front surface. Since the non-reflectorized front surface allows most of the light to go through, only a small amount of light is reflected into the driver's eyes.

[edit] Automatic dimming

Other rear-view mirrors have electronic auto-dimming feature built in so the driver is not blinded by glare, these systems use a camera sensor usually mounted to the actual rear-view mirror which detects light and then dims the mirror. These designs include an older mechanical dimming feature and a more modern electrochromic dimming feature. This electrochromic feature has been also incorporated into side-view mirrors allowing them to dim and reduce glare as well. Mirrors containing such features can, however, be not sensitive enough for many drivers.

[edit] Bicycles

Some bicycles are equipped with rear-view mirrors mounted the handlebars. Some cyclists also choose to mount rear-view mirrors to a helmet or the frame of a pair of eyeglasses.

[edit] Computers

In an effort to prevent Identity theft, some computer users make use of rear-view mirrors to discourage others from looking over the user's shoulder and seeing sensitive information.[citation needed]

[edit] See also

[edit] References

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