LCDs are all around us. Liquid crystal displays are so common, in fact that most people can’t get through their day without using one. This technology is utilized in digital clocks, microwave ovens, car dashboards, calculators, stereos, thermometers, and even some bathroom scales. The applications for liquid crystal displays are almost limitless and have revolutionized the most basic home appliance, the television set. But how does it work?

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. 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.

In 1996, the Federal Communications Commission (FCC) enacted legislation convincing the nation's 1600+ television stations to change the way they broadcast their programming and to start transmitting it digitally. Digital Television (DTV) began rising in America ever since then. For now, the FCC allows the media to offer digital broadcasts in parallel with their existing analog ones, giving consumers the opportunity to watch regular TV while they make the switch to DTV.

Once the transition to digital TV is complete it is estimated that by the year 2006 85% of US households will get digital feeds, meaning that DTV will be the new standard in broadcasting replacing analog broadcasting. Sure, you'll still be able to watch your favorite shows in analog like always, but you'll need to "update" your existing TV with a device that converts digital signals into analog ones. All of which begs the question: Why not just go with the digital flow?

It's easier to watch Just like Plasma Televisions flat-panel displays like LCDs are significantly brighter and feature higher contrasts than traditional CRT sets. This means that an LCD Television will perform remarkably well under most ambient light conditions. A brightly lit room won't wash out its picture, and lamplight won’t cause a glare on your LCD television screen. The beauty of these flat screens is that you don't have to turn out the lights to see the image clearly and easily. You don’t have to worry about any strain on your eyes either, since LCDs don’t flicker the way old-fashioned TVs do.

Viewing Angle You can watch TV from almost anywhere in a room since flat-screen LCD displays can have up to a 160° viewing angle, which means your LCD Television will look good when viewed from any point 80° in either direction from the center of the display.

Tuner is included Unlike many Plasma Televisions LCD TVs generally come with tuners and speakers already built in, so they're more or less plug-and-play devices. Since most LCD TVs don't require external tuning devices, they are ideal for smaller applications, where space is a concern (like bedrooms and small living rooms) or where clutter is inconvenient.

Picture is smooth, colorful, and wide LCD Televisions have none of those annoying scan lines that conventional sets do. This owes to the fact that each sub pixel has its own transistor electrode, which creates smooth, evenly lit images across the entire surface of the display. It also enables these displays to reproduce images that are saturated with color. (256 shades of red x 256 shades of green x 256 shades of blue = 16.8 million different colors).

The display is multi-functional and long-lived An LCD is a television monitor, capable of displaying HDTV, regular TV, and home video. It's also a computer monitor. In fact, it can accept any video format. LCD displays include many inputs including composite video, S-video and component video, and one or more RGB inputs from a computer. Because of the high resolution of LCDs, text and graphics look especially sharp when viewed on them, which makes them the best solution for displaying data and web-based content.

You can expect to use your LCD monitor in many capacities for many years: The average lifespan of one of these displays is 60,000 hours. If watching TV was your full-time job, and you did it 24 hours a day, it would take you almost 7 years to wear out your LCD display. With more normal viewing habits of, say, 8 hours per day, you can extend the lifespan of your TV by a decade or more (to about 20 years)!

LCD VS Plasma - At first if you were dreaming of a super size flat screen for your home entertainment center Plasma Televisions were your only option. But recently large-format LCD TVs have been competing with plasma displays in prices and sizes.

Right now, Plasma Televisions have an advantage and that’s partly because, at the moment, large LCD Televisions simply can't compete on price. It's also because plasma screens have a greater response time than most LCD TVs which makes LCD Televisions less than optimal for moving images such as video or games. The drawbacks that Plasma TV screens had in the past such as stationary images burning in and producing permanent ghosting has diminished greatly in newer products. For example, some new companies have developed technology to deal with the problem by moving stationary pixels just enough to prevent such burn-in.

But LCD Televisions do have some advantages over plasma. If you're contemplating a home entertainment setup involving a PC or other activities involving text as well as graphics, you'll get a crisper, brighter image from an LCD. LCD modules are in use for all types of products, from handhelds to monitors to TVs. As time passes larger LCD TVs will be available at lower prices, because they offer better screen quality, higher reliability (LCD TVs have none of the burn-in issues associated with plasma), and longer product life. LCD Televisions last for about 50,000 hours versus 30,000 hours for today's plasma screens. LCD TVs weigh 10 to 15 percent less than plasmas of comparable size. They often look better in daylight than plasmas, though plasmas have a brightness advantage at night.

LCD VS CRT Monitors - Free from the bulky shape and size of the CRT screen an LCD Screen is light and slim in size, compare a 15-inch deep, 30-pound CRT against a panel that's less than 7 inches deep (including the base) and weighs 12 or 13 pounds. It's easy to see the advantages of LCD monitors, they don't have CRT's focus problems, and their clarity makes it easier to view higher resolutions at smaller screen sizes. The latest LCD monitors are all digital, unlike CRTs this means that graphics cards with digital outputs don't have to convert the graphics information into analog form as they would with a typical CRT monitor. With LCD TVs you will get a high quality image with very little eyestrain due to the flat screen and the screens do not flicker unlike in the CRTs.

Dead Pixels - A flat panel LCD may contain some "dead" or faulty pixels. These are usually easy to spot: they show a constant color. Dead pixels are the result of the manufacturing process and they cannot be "revived". Dead pixels can be irritating, especially if you use the flat panel to watch movies, if you cannot accept dead pixels, make sure you check the screen first before buying.

Aspect Ratio - LCD displays come either with a 16:9 aspect ratio (16 units wide to 9 units high), the proper one for viewing HDTV and for watching DVDs, or with a 4:3 aspect ratio, the norm for most broadcast television shows. If you decide to go with a widescreen (16:9) display, it doesn’t mean that you'll have to watch some shows that are not shown in widescreen format with images distorted or stretched unnaturally. When displaying a "normal" or 4:3 picture image from satellite, VCR, or cable TV, the image can be viewed in a number of ways-in its original format (with black or gray bars on the sides of the screen), or in "full" mode (where the image is converted or "stretched" using specially designed algorithms to reduce the visible stretch marks as much as possible). Again, the quality of the picture produced under such circumstances depends largely on the quality of the television you purchase.

Viewing Angle - If you’ve used a notebook computer before, you'll know that the LCD offers the best view when you look at it at a certain angle. Some LCD monitors have wide viewing angles, thereby enabling you to see what's on the screen even if don't view it directly in front of you. However, some people find narrow view angles in notebook computers useful, since they prevent other sitting close to you to see what's on your screen. Above 120 degree is considered good.

Contrast Ratio - The LCD doesn't emit light on its own but relies on a backlight to illuminate the screen. A dark screen doesn't mean the backlight isn't working; the pixel merely block off the light from transmitted through the liquid crystal layer. The contrast ratio is measure of how many brightness levels the LCD can have. Generally, a contrast ratio of over 250:1 is considered good.

Brightness - How bright can an LCD be? The truth is the LCD can be brighter than a CRT. But generally, the maximum brightness of the LCD is around 225 candelas per square meter, compared to the brightness of a TV screen.

Screen Size - Like conventional CRTs, the LCD is also measured in terms of its diagonal screen size. However, take a note that the LCD doesn't have a black border like the CRT. Thus, a 15.1" LCD shows the full 15.1" screen (which typically is 1024 x 768 pixel resolution). A 17.1" LCD will show 1280 x 1024 pixel resolution.