Frontlight
Encyclopedia
A frontlight is a means of illuminating
a display device
, usually a liquid crystal display
(LCD), which would otherwise be viewed in ambient light. This improves its performance in poor lighting conditions. Frontlights are inferior to backlight
s and are usually found as an auxiliary
feature.
An LCD presents an image by absorbing some light passing through it. When an electric field is applied across the crystal, it changes the passing light so it will not pass through a polarization filter
. This allows LCDs to operate at low power
, as no energy needs to be spent generating light. Many battery-operated electronic devices, including most calculators, use unilluminated LCDs.
An unilluminated LCD must be lit from the front. To use ambient light, the liquid crystal itself is sandwiched between a polarization filter and a reflective surface. The mirror makes the display opaque so it cannot be illuminated from the back. Most often a light source is placed around the perimeter
of the LCD.
Frontlights are relatively uncommon. Electroluminescent lights present a reflective surface when turned off. This allows for a backlit display which can also be used with ambient light. Such backlights are popular in digital watches. The monochromatic light from an electroluminescent source does not work well with color displays, however. An incandescent frontlight was therefore a popular accessory for the Nintendo
Game Boy Color
.
Lighting
Lighting or illumination is the deliberate application of light to achieve some practical or aesthetic effect. Lighting includes the use of both artificial light sources such as lamps and light fixtures, as well as natural illumination by capturing daylight...
a display device
Display device
A display device is an output device for presentation of information in visual or tactile form...
, usually a liquid crystal display
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
(LCD), which would otherwise be viewed in ambient light. This improves its performance in poor lighting conditions. Frontlights are inferior to backlight
Backlight
A backlight is a form of illumination used in liquid crystal displays . As LCDs do not produce light themselves , they need illumination to produce a visible image...
s and are usually found as an auxiliary
Auxiliary
Auxiliary may refer to:* A backup site or system* Auxiliary input jack, generally for audio* Auxiliary verb* International auxiliary language* Auxiliary police* Auxiliaries, troops supporting the main force of an army** Auxiliaries...
feature.
An LCD presents an image by absorbing some light passing through it. When an electric field is applied across the crystal, it changes the passing light so it will not pass through a polarization filter
Polarizer
A polarizer is an optical filter that passes light of a specific polarization and blocks waves of other polarizations. It can convert a beam of light of undefined or mixed polarization into a beam with well-defined polarization. The common types of polarizers are linear polarizers and circular...
. This allows LCDs to operate at low power
Low-power
In electronics, the term low-power may mean:* Low-power broadcasting, that the power of the broadcast is less, i.e. the radio waves are not intended to travel as far as from typical transmitters....
, as no energy needs to be spent generating light. Many battery-operated electronic devices, including most calculators, use unilluminated LCDs.
An unilluminated LCD must be lit from the front. To use ambient light, the liquid crystal itself is sandwiched between a polarization filter and a reflective surface. The mirror makes the display opaque so it cannot be illuminated from the back. Most often a light source is placed around the perimeter
Perimeter
A perimeter is a path that surrounds an area. The word comes from the Greek peri and meter . The term may be used either for the path or its length - it can be thought of as the length of the outline of a shape. The perimeter of a circular area is called circumference.- Practical uses :Calculating...
of the LCD.
Frontlights are relatively uncommon. Electroluminescent lights present a reflective surface when turned off. This allows for a backlit display which can also be used with ambient light. Such backlights are popular in digital watches. The monochromatic light from an electroluminescent source does not work well with color displays, however. An incandescent frontlight was therefore a popular accessory for the Nintendo
Nintendo
is a multinational corporation located in Kyoto, Japan. Founded on September 23, 1889 by Fusajiro Yamauchi, it produced handmade hanafuda cards. By 1963, the company had tried several small niche businesses, such as a cab company and a love hotel....
Game Boy Color
Game Boy Color
The is Nintendo's successor to the 8-bit Game Boy handheld game console, and was released on October 21, 1998 in Japan, November 19, 1998 in North America, November 23, 1998 in Europe and November 27, 1998 in the United Kingdom. It features a color screen and is slightly thicker and taller than...
.