A graphic LCD (liquid crystal display) is an electronic visual displaytechnologyused in different gadgets and information-output sources, mostly in display screens of electronic devices. This technology employs manipulating tiny crystals of a contained liquid crystal solution through precise electronic signals to perform graphic display operations over a two-dimensional physical screen. LCD technology is considered the successor of conventional CRT (cathodelcd ray tube) visual display technology, which uses electron-firing gun to produce a pixel-based display over monitor screens.
Operational Assembly
LCDs are thin and compact visual display units, having a very closely integrated structural assembly. In its normaldesign, a graphic LCD is comprised of five basic layers arranged in parallel to each other. The first layer consists of an array of light sources illuminating polarizing filter in the second layer, thus transforming and changing the polarization (or orientation) of the transmitted light signals. These polarized signals then hit the third layer constituted of transistor-based pixels (tiniest unit of display), and this process actually determines the color and shape of graphics image to be displayed. Ultimately, the constructed shape at third layer is carried to the fourth layer containing a liquid crystal solution, which arranges its crystals to form a distinct image. This image is finally polarized on the fifth layer of glass or plastic, through which the image is displayed.
Categories
The categorization of LCD is usually carried out over the technology which it uses to perform displaying operations. There are two major categories of graphic LCDs, known as passive matrix addressed LCDs and active matrix addressed LCDs. A passive matrix LCD has limited displaying characteristics, and performs its graphics operations by refreshing the states of its pixels through state-changing electrical signals. In contrast to this, an active matrix LCD has a layer of TFT (thin film transistors) integrated within its layers, which assigns each pixel with its own state-changing transistor, and thus, has a more clear and dynamic graphic display result. This type of LCD can further be categorized into six subtypes, including TN (twisted nematic), HTN (high twisted nematic), STN (super twisted nematic), FSTN (film-compensated twisted nematic), DSTN (double super twisted nematic), and CSTN (color super twisted nematic) active matrix LCDs.
Common Applications
The most common application of LCD is found in cell phones screens, laptop computer screens, LCD monitors, calculators, digital readers, electronic diaries and watches, flat-screen televisions, and many other electronic devices or gadgets that display information in visual or text-based format. Moreover, significant advancements into the design and operational assembly of LCDs have made it possible to be used as device capable of both input and output operations.
Advantages
Graphic LCDs offer multiple significant advantages over traditional CRT-based visual display units. Some major advantages include compact and thin dimensions, more detailed display of 3-D (three-dimensional) objects, lowerpowerconsumption, and lighter weight. Furthermore, all these features have considerably contributed towards integration of these visual display units into commercial portable electronic items.
