How does a LCD (Liquid Crystal Diode) TV operate?



LCD monitors work by blocking light. By sandwiching a solution of TN liquid crystals between two perpendicularly aligned panes of polarized glass, it becomes possible to manipulate the intensity of light as it passes through this crystalline matrix and out the glass panel at the other end. Depending on the voltage of the electrical charge running through them, liquid crystals will untwist so that the intensity of light able to pass through the second polarized pane is affected. Basically, these displays can switch between light states (where the liquid crystals are fully twisted) and dark states (where the liquid crystals are fully untwisted), or somewhere along the gray scale in between.

Addressing: A liquid crystal display consists of an array of tiny segments-called "pixels"-that are manipulated to form images or to present information. Addressing is the process by which pixels are turned on (which disables the passage of light) and off (which enables the passage of light) so as to create an image on the polarized display pane in front of you. So-called active-matrix LCD TVs employ thin film transistors (TFTs), or tiny switching transistors and capacitors arranged in a matrix on a glass substrate, to direct electric charges down columns to reach a particular pixel. This, in turn, causes the liquid crystals to untwist and "display" a predetermined amount of light generated by the light source-usually a florescent bulb-in back of them.

Color (Re) Production: The light source in an active-matrix LCD monitor is a florescent bulb, which emits white light through a polarized glass pane behind the liquid crystal solution. Theoretically, then, you can start with a white display: This is one where its liquid crystals are completely twisted and therefore able to direct the full spectrum of light out through the polarized display screen in front of you. Since all wavelengths can pass through, the full spectrum of light can be manipulated to create the desired color. To achieve a full color pallet on your LCD display, each pixel is divided into three subpixels-red, green, and blue-that work in conjunction to determine the LCD pixel's overall hue. These subpixels are created by subtracting certain wavelengths, and the color(s) corresponding thereto, using special filters. By exploiting a combination of red, green, and blue subpixels of various intensities (or gray scales), a single pixel triad can reproduce approximately 16.8 million colors.


© Copyright 2018 Cahnerselectronics. All rights reserved.
Unauthorized duplication in part or whole strictly prohibited by international copyright law.