Text display
Encyclopedia
A text display is an electronic alphanumeric
display device
that is mainly or only capable of showing text
, or extremely limited graphic character
s. This includes electromechanical split-flap display
s, vane display
s, and flip-disc display
s; all-electronic liquid-crystal displays, incandescent eggcrate displays, LED display
s, and vacuum fluorescent display
s; and even electric nixie tube
s.
There are several ways to form text for display. A segment display uses lines, while a dot-matrix display uses a grid of dots
, and both of these are seen in LCD, LED, VFD, and vane/disc types. For split-flap displays, the characters or words are pre-printed, and for nixie tubes the shapes are also pre-formed. In any case, the display elements are controlled by electronics which activate them in the correct physical and temporal
sequence to show the desired information.
Text displays are used in everything from clock
s (clock radios, wristwatches) to variable-message signs (departure boards, intelligent transportation system
s), because up until the late 2000s, they were (and in many cases still are) the least expensive for their purpose.
, electronic visual display
, video display that uses the light modulating properties of liquid crystals (LCs). LCs do not emit light directly. A charachter display type is limited to and specialized for display of alphanumeric characters.
They are used in a wide range of applications, including computer monitors, television
, instrument panels, aircraft cockpit displays
, signage
, etc. They are common in consumer devices such as video players, gaming devices, clock
s, watches, calculator
s, and telephone
s.
The low electrical power consumption of LCD displays enables them to be used in battery
-powered electronic
equipment. It is an electronically modulated optical device
made up of any number of pixel
s filled with liquid crystal
s and arrayed in front of a light source (backlight
) or reflector
to produce images in color or monochrome
. The earliest discovery leading to the development of LCD technology, the discovery of liquid crystals, dates from 1888.
By 2008, worldwide sales of televisions with LCD screens had surpassed the sale of CRT units.
s. A foam rubber mask with an array of holes surrounding the bulbs is attached to the display, causing it to resemble an egg crate.
Some eggcrate displays use a complete 5×7 matrix for each digit, permitting the display of nearly all alphanumeric characters. Other types display only numeric characters and optionally a dollar sign. This type of eggcrate display is popularly used for sports scoreboard
s.
Eggcrate displays have been used on many game show
s to display contestants' scores and/or for countdown clocks because other types of displays, such as LED
seven-segment display
s, were prone to being washed out by bright studio lights. Though they continued to see extensive use well into the late 1990s, game show
s that used eggcrate displays have switched to either plasma or liquid crystal displays in the 2000s and beyond, as shows began switching to high-definition broadcasts.
and VFD
segmented displays, vane displays are composed of seven physical surfaces, typically painted white, but occasionally other colors, such as yellow or fluorescent green. If a segment is to be displayed as "off", it will be rotated so that its edge faces forward, with the painted surface pointing away and not visible. A segment that is to be displayed as "on" will be rotated so that the painted surface is shown.
Alphanumeric
Alphanumeric is a combination of alphabetic and numeric characters, and is used to describe the collection of Latin letters and Arabic digits or a text constructed from this collection. There are either 36 or 62 alphanumeric characters. The alphanumeric character set consists of the numbers 0 to...
display device
Display device
A display device is an output device for presentation of information in visual or tactile form...
that is mainly or only capable of showing text
Plain text
In computing, plain text is the contents of an ordinary sequential file readable as textual material without much processing, usually opposed to formatted text....
, or extremely limited graphic character
Graphic character
In ISO/IEC 646 and related standards including ISO 8859 and Unicode, a graphic character is any character intended to be written, printed, or otherwise displayed in a form that can be read by humans...
s. This includes electromechanical split-flap display
Split-flap display
A split-flap display, sometimes simply flap display, is a display device that presents alphanumeric text, and possibly fixed graphics, often used as a public transport timetable in some airports or railway stations, often called Solari boards, named after display manufacturer Solari di...
s, vane display
Vane display
A vane display is a type of 7-segment display. Unlike LED and VFD segmented displays, vane displays are composed of seven physical surfaces, typically painted white, but occasionally other colors, such as yellow or fluorescent green. If a segment is to be displayed as "off", it will be rotated so...
s, and flip-disc display
Flip-disc display
The flip-disc display is an electromechanical dot matrix display technology used for large outdoor signs, normally those that will be exposed to direct sunlight. Flip-disc technology has been used on buses across North America and Europe. It has also been used extensively on public information...
s; all-electronic liquid-crystal displays, incandescent eggcrate displays, LED display
LED display
An LED display is a flat panel display, which uses light-emitting diodes as a video display. An LED panel is a small display, or a component of a larger display. They are typically used outdoors in store signs and billboards, and in recent years have also become commonly used in destination signs...
s, and vacuum fluorescent display
Vacuum fluorescent display
A vacuum fluorescent display is a display device used commonly on consumer-electronics equipment such as video cassette recorders, car radios, and microwave ovens. Invented in Japan in 1967, the displays became common on calculators and other consumer electronics devices...
s; and even electric nixie tube
Nixie tube
A nixie tube is an electronic device for displaying numerals or other information. The glass tube contains a wire-mesh anode and multiple cathodes. In most tubes, the cathodes are shaped like numerals. Applying power to one cathode surrounds it with an orange glow discharge...
s.
There are several ways to form text for display. A segment display uses lines, while a dot-matrix display uses a grid of dots
Dot matrix
A dot matrix is a 2-dimensional array of LED used to represent characters, symbols and images.Typically the dot matrix is used in older computer printers and many digital display devices. In printers, the dots are usually the darkened areas of the paper...
, and both of these are seen in LCD, LED, VFD, and vane/disc types. For split-flap displays, the characters or words are pre-printed, and for nixie tubes the shapes are also pre-formed. In any case, the display elements are controlled by electronics which activate them in the correct physical and temporal
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
sequence to show the desired information.
Text displays are used in everything from clock
Clock
A clock is an instrument used to indicate, keep, and co-ordinate time. The word clock is derived ultimately from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a mechanism has traditionally been known as a timepiece...
s (clock radios, wristwatches) to variable-message signs (departure boards, intelligent transportation system
Intelligent transportation system
The term intelligent transportation systems refers to information and communication technology that improve transport outcomes such as transport safety, transport productivity, travel reliability, informed travel choices, social equity, environmental performance and network operation...
s), because up until the late 2000s, they were (and in many cases still are) the least expensive for their purpose.
LED text displays
LED text displays refer to types that are specialized and limited to display of alpha-numeric characters. Most types display either one character or a group of characters. One character is generally displayed by a matrix of LED's, or by a set of segments.Liquid crystal display
A liquid crystal display (LCD) is a flat panel displayFlat panel display
Flat panel displays encompass a growing number of electronic visual display technologies. They are far lighter and thinner than traditional television sets and video displays that use cathode ray tubes , and are usually less than thick...
, electronic visual display
Electronic visual display
An electronic visual display is display technology which incorporates flat panel displays, performs as a video display, output device for presentation of images transmitted electronically, for visual reception, without producing a permanent record....
, video display that uses the light modulating properties of liquid crystals (LCs). LCs do not emit light directly. A charachter display type is limited to and specialized for display of alphanumeric characters.
They are used in a wide range of applications, including computer monitors, television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
, instrument panels, aircraft cockpit displays
Flight instruments
Flight instruments are the instruments in the cockpit of an aircraft that provide the pilot with information about the flight situation of that aircraft, such as height, speed and altitude...
, signage
Signage
Signage is any kind of visual graphics created to display information to a particular audience. This is typically manifested in the form of wayfinding information in places such as streets or inside/outside of buildings.-History:...
, etc. They are common in consumer devices such as video players, gaming devices, clock
Clock
A clock is an instrument used to indicate, keep, and co-ordinate time. The word clock is derived ultimately from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a mechanism has traditionally been known as a timepiece...
s, watches, calculator
Calculator
An electronic calculator is a small, portable, usually inexpensive electronic device used to perform the basic operations of arithmetic. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.The first solid-state electronic...
s, and telephone
Telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...
s.
The low electrical power consumption of LCD displays enables them to be used in battery
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
-powered electronic
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
equipment. It is an electronically modulated optical device
Electro-optic modulator
Electro-optic modulator is an optical device in which a signal-controlled element displaying electro-optic effect is used to modulate a beam of light. The modulation may be imposed on the phase, frequency, amplitude, or polarization of the modulated beam...
made up of any number of pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
s filled with liquid crystal
Liquid crystal
Liquid crystals are a state of matter that have properties between those of a conventional liquid and those of a solid crystal. For instance, an LC may flow like a liquid, but its molecules may be oriented in a crystal-like way. There are many different types of LC phases, which can be...
s and arrayed in front of a light source (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...
) or reflector
Reflector (photography)
In photography and cinematography, a reflector is an improvised or specialised reflective surface used to redirect light towards a given subject or scene.- Types :...
to produce images in color or monochrome
Monochrome
Monochrome describes paintings, drawings, design, or photographs in one color or shades of one color. A monochromatic object or image has colors in shades of limited colors or hues. Images using only shades of grey are called grayscale or black-and-white...
. The earliest discovery leading to the development of LCD technology, the discovery of liquid crystals, dates from 1888.
By 2008, worldwide sales of televisions with LCD screens had surpassed the sale of CRT units.
Eggcrate displays
An eggcrate display is one older method of displaying an alphanumeric character. It consists of a matrix of incandescent light bulbIncandescent light bulb
The incandescent light bulb, incandescent lamp or incandescent light globe makes light by heating a metal filament wire to a high temperature until it glows. The hot filament is protected from air by a glass bulb that is filled with inert gas or evacuated. In a halogen lamp, a chemical process...
s. A foam rubber mask with an array of holes surrounding the bulbs is attached to the display, causing it to resemble an egg crate.
Some eggcrate displays use a complete 5×7 matrix for each digit, permitting the display of nearly all alphanumeric characters. Other types display only numeric characters and optionally a dollar sign. This type of eggcrate display is popularly used for sports scoreboard
Scoreboard
A scoreboard is a large board for publicly displaying the score in a game or match. Most levels of sport from high school and above use at least one scoreboard for keeping score, measuring time, and displaying statistics. Scoreboards in the past used a mechanical clock and numeral cards to...
s.
Eggcrate displays have been used on many game show
Game show
A game show is a type of radio or television program in which members of the public, television personalities or celebrities, sometimes as part of a team, play a game which involves answering questions or solving puzzles usually for money and/or prizes...
s to display contestants' scores and/or for countdown clocks because other types of displays, such as LED
Light-emitting diode
A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
seven-segment display
Seven-segment display
A seven-segment display , or seven-segment indicator, is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot-matrix displays...
s, were prone to being washed out by bright studio lights. Though they continued to see extensive use well into the late 1990s, game show
Game show
A game show is a type of radio or television program in which members of the public, television personalities or celebrities, sometimes as part of a team, play a game which involves answering questions or solving puzzles usually for money and/or prizes...
s that used eggcrate displays have switched to either plasma or liquid crystal displays in the 2000s and beyond, as shows began switching to high-definition broadcasts.
Vane displays
A vane display is a type of 7-segment display. Unlike LEDLight-emitting diode
A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
and VFD
Vacuum fluorescent display
A vacuum fluorescent display is a display device used commonly on consumer-electronics equipment such as video cassette recorders, car radios, and microwave ovens. Invented in Japan in 1967, the displays became common on calculators and other consumer electronics devices...
segmented displays, vane displays are composed of seven physical surfaces, typically painted white, but occasionally other colors, such as yellow or fluorescent green. If a segment is to be displayed as "off", it will be rotated so that its edge faces forward, with the painted surface pointing away and not visible. A segment that is to be displayed as "on" will be rotated so that the painted surface is shown.