![]() The best known is IPS (In Plane Switching) LCD. Based on TFT LCD, even more modern LCD technologies are developed. The most widely used is TFT (Thin Film Transistor) LCD technology. In order to improve upon the drawbacks, scientists and engineers developed active matrix LCD technology. Passive matrix LCDs have a lot of limitations, like the narrow viewing angle, slow response speed, dim, but it is great for power consumption. The most basic LCD introduced above is called passive matrix LCDs which can be found mostly in low end or simple applications like, calculators, utility meters, early time digital watches, alarm clocks etc. When it reaches the second polarizer, it will also pass through, the viewer sees the display is bright.īecause LCD technology uses electric fields instead of electric current (electron passes through), it has low power consumption.Ī short Youtube video will explain how LCDs concisely and efficiently. When the polarized light reaches the layer of liquid crystal molecules, the light passes straight through without being twisted. When an electric field is applied to the liquid crystal molecules, they are untwisted. ![]() When it reaches the second polarizer, it is blocked. When the light either from ambient light or from the backlight passes through the first polarizer, the light is polarized and twisted with the liquid crystal molecular layer. The principle behind the LCDs is that when an electrical field is not applied to the liquid crystal molecules, the molecules twist 90 degrees in the LCD cell. The first LCD panel technology in mass production is called TN (Twisted Nematic). You can also add a touch panel in front of an LCD.įig. Of course, if you like to have a color display, a layer of color filter can be made into an LCD cell. ![]() The light sources for backlight can be LED (Light Emitting Diode) or CCFL (Cold Cathode Fluorescent Lamps). The electrodes need to be transparent, so the most popular material is ITO (Indium Tin Oxide).Īs LCD can’t emit light itself, normally a backlight is placed behind an LCD screen in order to be seen during the dark environment. A polarizer is an optical filter that lets light waves of a specific polarization pass through while blocking light waves of other polarizations. How LCDs are Constructed?Īn LCD screen includes a thin layer of liquid crystal material sandwiched between two electrodes on glass substrates, with two polarizers on each side. By adjusting the individual levels of red, green, and blue light, millions of color combinations are obtained. When all the sub-pixels are turned on 100%, it appears white. When all of a pixel’s sub-pixels are turned off, it appears black. Each pixel has a RGB (Red, Green, and Blue) sub-pixel that can be turned on or off. Instead of firing electrons at a glass screen, an LCD has a backlight that provides light source to individual pixels arranged in a rectangular grid. LCD displays don’t just look different from bulky CRT (Cathode Ray Tube) monitors, the way they operate is significantly different as well. It is also used in screens for mobile devices, such as laptops, tablets, and smartphones. Stands for “Liquid Crystal Display.” LCD is a flat panel display technology commonly used in TVs and computer monitors.
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