Friday, June 24, 2011

Liquid Crystal Display (LCD) Computer - Get The Best Device

Nowadays, with the advent in technology, you can easily find futuristic and high tech LCD flat screen computers. The LCD computer has been described as Liquid Crystal Display, which is designed with flat and thin display. It is made up of a range of attractive colors or monochrome pixels array in front of a light source or reflector. In this regard, passive matrix and active matrix are used by color LCDs for producing colors.
  • Passive matrix: In recent time, passive matrix is considered as one of the most popular displays used in computers, which is available at reasonable rates. For graphical user interfaces, it usually provides good contrast and viewing angle. Additionally, it includes a grid of horizontal and vertical wires that will either block the light or let it through.
  • Active-matrix: It is an expensive technology that produces sharper color images. This technology is also known as TFT (thin film transistor), which is perfect for multimedia applications with video images. To control each pixel, it uses one to four transistors.
Apart from computer monitor, liquid crystal display is probably available in numerous other electronic devices such as microwave ovens, video players, gaming devices, calculators, digital clocks, laptops, watches and CD players etc.

Thus, it is recommended that before buying any of the newest LCD monitor, it is important to evaluate its various factors like resolution, spatial performance, viewing angle, color performance, brightness and contrast ratio.

History Of LCD flat screen monitor

1858 to 1927, Liquid crystalline nature of cholesterol extracted from carrots was discovered by Friedrich Reinitzer. On May 3, 1888, at the meeting of Vienna Chemical Society, F. Reinitzer published his findings.

Work on Fl├╝ssige Kristalle (Liquid Crystals) took place by Otto Lehmann, which was published in 1904.

First experiments of Liquid crystals confined to plates in thin layers by Charles Mauguin in 1911.

In 1922, structure and properties of liquid crystals and their classifications (smectics, nematics and cholesterics) were elaborated by Georges Friedel.

“The Liquid Crystal Light Valve” is the first practical application of the technology made by the Marconi Wireless Telegraph Company in 1936.

In 1962, Dr George W. Gray introduced "Molecular Structure and Properties of Liquid Crystals", the first major English language publication on the then emerging LCD technology.

Richard Williams of RCA originated liquid crystals including electro-optic characteristics in 1962.

In 1964, the switching of colors by field-induced realignment of dichroic dyes in a homeotropically oriented liquid crystal was observed by George H. Heilmeier, while working on the effect discovered by Williams in the RCA laboratories. Due to some practical problems with new electro-optical effect, Heilmerier continued working on same project and finally, the first operational liquid crystal display based on the dynamic scattering mode (DSM) was achieved. Consequently, in the National Inventors Hall of Fame, George H. Heilmeier was credited for the induction of LCD.

In late 1960s, innovatory work on liquid crystals was undertaken by the UK's Royal Radar Establishment at Malvern, England.

Further, on December 4, 1970, Hoffman-LaRoche in Switzerland with Wolfgang Helfrich and Martin Schadt filed for copyright of the twisted nematic field effect in liquid crystals. In the same year, Roche and Japanese electronics industry was licensed for wrist watches manufactured by Brown, Boveri & Cie and soon produced the first digital quartz wristwatches with TN-LCDs.

Westinghouse in Pittsburgh (US) produced first active-matrix liquid crystal display panel in 1972.

The optical patterning technique with multi-domain was developed by Samsung in 1996.

Later on, in 1997, the first LCD was produced with acceptable visual quality for TV application by Hitachi with revived In-Plane-Switching (IPS) technology.

In 2007, the sales of CRT units were surpassed by LCD for the first time. In 2008, almost 200 million TVs were forecasted to ship globally.

Working Of LCD flat screen monitor

LCD monitors contain two display controls including:
  • Electrics of the pixels
  • Light source
Here, the signal comes in and the video controller is decoded, which is understood by a display controller on the monitor itself.

A matrix of pixels is used to make image on a TFT. It includes simple native resolution of the monitor. For a 17" monitor, the specifications for a matrix are 1280 pixels (horizontally) and 1024 pixels (vertically).

Three sub-pixels of RGB phosphors (red/green/blue) are used for making each pixel. Groups of liquid crystal molecules are essential for subpixels, which are mashed between two polarizing filters (exactly opposite of each other) and hovered between transparent electrodes.

The filter effectively whites it out; as the light from the light source comes in behind the first filter (the filter will polarize light back to back, when it passes through liquid crystal without any contact with it).

The way through which light passes is changed and twisted, when the current to liquid crystals is applied by electrodes. Thus, altering its polarization, the correct color is represented to the viewer through second polarizing filter.

Here, cold cathode is considered as the backlight. The optimum brightness and clarity depends on the display and cathode.

  • A single cathode at the top
  • One at the top and one at the bottom
  • Two at the top and two at the bottom
A layer of plastic is used to diffuse the cathodes that you might find installed on a flashgun diffuser for photography.
  • Wide screen display
  • Touch screen
  • Compact and portable
  • Reliable
  • Thinner and lighter
  • Consumes less power when in use
  • Astonishing picture quality
  • Black, silver or beige LCD
  • Flat screen that will not cover much space

Sizes Of LCD computer

LCD monitors are availability in various panels like 15 inches or less, 17 inches, 19 inches, 20 inches, 21 inches, 22 inches, 23 inches or larger and so on.

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