A rear-view mirror is a mirror in automobiles and other vehicles, designed to allow the driver to see rearward through the vehicle's backlight (rear windscreen).
In cars, the rear-view mirror is usually 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.
For motorcycles and bicycles, the rear-view mirrors are usually mounted to the handlebars, and there are usually two of them, so they are variously referred to as "rear-view mirrors", "side-view mirrors", "side mirrors", or simply "mirrors".
Contents |
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 to develop it for incorporation into production streetgoing automobiles.
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.
A prismatic rear-view mirror — sometimes called a "day/night mirror" — can be tilted to reduce the brightness and glare of lights, mostly for headlights shining directly on the eye level at night. This type of mirror is made of a piece of glass that is wedge-shaped in cross section—its front and rear surfaces are not parallel.
On manual tilt versions, a tab is used to adjust the mirror between "day" and "night" positions. 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.
In the 1950s, American inventor Jacob Rabinow developed a light-sensitive automatic mechanism for the wedge-type day/night mirror.[5] Several Chrysler Corporation cars offered these automatic mirrors as optional equipment as early as 1959, but few customers ordered them for their cars and the item was soon withdrawn from the option lists. Several automakers began offering rear-view mirrors with automatic dimming again in 1983, and it was in the late 1980s that they began to catch on in popularity.
Current systems usually use photo sensors mounted in the actual rear-view mirror to detect light and dim the mirror by means of electrochromism. This electrochromic feature has been also incorporated into side-view mirrors allowing them to dim and reduce glare as well.
Depending on the type of motorcycle, the motorcycle may or may not have rear-view mirrors. Street-legal motorcycles are generally required to have rear-view mirrors. Motorcycles for off-road use only normally do not have rear-view mirrors. Rear-view mirrors come in various shapes and designs, and have various methods of mounting the mirrors to the motorcycle, most commonly to the handlebars. Rear-view mirrors can also be attached to the rider's motorcycle helmet.
Some bicycles are equipped with rear-view mirrors mounted to the handlebars. Cyclists may also choose to mount rear-view mirrors to a helmet or the frame of a pair of eyeglasses, or the basket of the bicycle. The idea behind the bicycle mirror is rider safety. The bicycle mirror alleviates the problem of having to rotate your head and look over your shoulder, thus taking your concentration off of the roadway in front of you.
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. These are especially prevalent on automated teller machines.[6]
|
||||||||||||||||||||||||||||||||||||||||||||||||||