11-02-2016, 04:38 PM
Introduction
In the early 1970's, digital watches started showing up in the marketplace with a new and
different type of display-the liquid crystal display or LCD. The LCD displays used in these early digital watches were very different from the LEDs they replaced. While even a tiny LED display consumes a few milliwatts of power, the LCD consumes just microwatts of power. Hence, the LCDs are over 1000 times more efficient at their job than the LEDs.Since their commercialization in the '70s, LCDs are the most popular electronic display device, except one-the CRT. LCD flat full color panels are now challenging the CRT as displays for television and computers. There are also many hybrid systems that use LCD display technology.
Liquid crystals
There are 3 states of matter: solid, liquid, gas.
Solids states can be further categorised into: crystalline which has regular arrangement of
molecules; and amorphous where there is no regular structure. It is well known that Crystalline solids heat → Isotropic liquid.In 1888, an intermediate phase is discovered and is known as the crystalline liquid or liquid crystal. This phase is called the nematic phase. An example is 4-n-pentyl-4'-cyano-biphenyl (PCB). Since than, over 20,000 known compounds have been found to have the nematic phase. The main interest in these types of compound is that the nematic phase compounds with rod-like molecules can be aligned by varying an external electric field. Most of the liquid crystal displays (LCDs) produced today use either the twisted nematic (TN) or supertwisted nematic (STN) electro-optical effects.
In the early 1970's, digital watches started showing up in the marketplace with a new and
different type of display-the liquid crystal display or LCD. The LCD displays used in these early digital watches were very different from the LEDs they replaced. While even a tiny LED display consumes a few milliwatts of power, the LCD consumes just microwatts of power. Hence, the LCDs are over 1000 times more efficient at their job than the LEDs.Since their commercialization in the '70s, LCDs are the most popular electronic display device, except one-the CRT. LCD flat full color panels are now challenging the CRT as displays for television and computers. There are also many hybrid systems that use LCD display technology.
Liquid crystals
There are 3 states of matter: solid, liquid, gas.
Solids states can be further categorised into: crystalline which has regular arrangement of
molecules; and amorphous where there is no regular structure. It is well known that Crystalline solids heat → Isotropic liquid.In 1888, an intermediate phase is discovered and is known as the crystalline liquid or liquid crystal. This phase is called the nematic phase. An example is 4-n-pentyl-4'-cyano-biphenyl (PCB). Since than, over 20,000 known compounds have been found to have the nematic phase. The main interest in these types of compound is that the nematic phase compounds with rod-like molecules can be aligned by varying an external electric field. Most of the liquid crystal displays (LCDs) produced today use either the twisted nematic (TN) or supertwisted nematic (STN) electro-optical effects.