What is Liquid Crystal Display technology, and how does an LCD panel work? Why is LCD flat-panel display technology the most common display technology in use today?
In this easy-to-follow how-it-works guide to LCD flat-panel display technology, we look at the underlying technology that makes LCD panels work in order to represent numbers, words, and high-resolution images.
We explain the physical setup of a liquid crystal display and how this impacts the production of LCD panels. We highlight the main differences between backlight and reflective displays, passive vs. active LCD panel technology, and see how liquid crystal display panels generate color information. We also discuss the issue of 'bad' pixels and see why manufacturers never guarantee that LCD panels are 100% free of bad, stuck or dead pixels.
Liquid Crystal Display (LCD) devices have become an important part of everyday life. Their use range from wristwatches, calculators, and mobile phones, to more demanding high-resolution applications in test instrumentation, computer monitors and high definition CCFL and LED LCD HDTVs.
And the use of LCD panels is growing at an incredible fast rate. Suffice to say that during 2011, according to a DisplaySearch report, total LCD TV shipments reached a global 214 million units despite the very difficult year for the TV manufacturing industry. In addition, it is estimated that LCD TV sales amount to 89% of all flat-panel TV sales - making the LCD display the undisputable TV display of choice!
LCD displays have become so common because they offer a few advantages no other display technology has so far managed to achieve. LCD displays are slim; most LCD TVs hardly exceed 3" depth while most of the latest LED LCD TVs are just 1-inch thin! In addition, LCD display panels do not emit harmful electromagnetic radiation. The image produced by an LCD TV is often much easier on the eye than that produced by both plasma and CRT TVs. Equally important in the home entertainment and in the industry, LCD display panels are much lighter than either plasma or CRT TVs. And in a world where the energy bill is on the increase, CCFL-based LCD panels use 20 to 30 percent less power than the latest energy-efficient plasma displays, while the edge-lit LED LCD TVs consume less than 50% power of similar size plasma TVs.
Add an expected panel lifetime of close to 100,000 hours in contrast to the typically 20,000 hours of CRTs, and there you have one of the most versatile and robust display panel technologies available today. Mind you, liquid crystal displays do not represent the perfect display technology.
Aprt from the higher price in comparison to plasma displays—especially as one exceeds the 55-inch screen size—LCD displays have their drawbacks as well. In particular, LCD display panels still have a rather restricted viewing angle with respect to plasma and CRT TVs, and this is especially so with LED LCD TVs. In addition, pixel response time in LCD TVs is still a thousand times slower than that of plasma HDTVs. We are not saying that LCD and LED TVs are not capable of handling fast action content but there is a higher possibility of experiencing image lag issues when handling very fast action content on LCD TVs than on plasma HDTVs.