Step 1: What exactly is a Liquid Crystal Diode (LCD) TV?
What exactly is a Liquid Crystal Diode (LCD) TV?
LCDs are all around us. Liquid crystal displays so prevalent, in fact, that most people couldn'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, so it should come as no surprise that this technology has revolutionized the most basic home appliance of all-the television set.
Liquid crystal technology has given birth to those slim, cool-looking, bright displays that are popping up everywhere from bank lobbies to living rooms. But how does it work?
What makes a crystal "liquid"?
The twisted nematic (TN) liquid crystal is the most common type of liquid crystal being used in display applications today (e.g., LCD televisions, LCD monitors, and LCD projectors). It has a naturally twisted crystalline structure. A particular feature of this crystal is that it reacts to electric currents in predictable ways-i.e., by untwisting to varying degrees depending on the voltage of the current to which it is exposed. Hence the "liquid" part of the crystal's moniker: Rather than being an oxymoron (How can a solid also be a liquid?), the term refers to the relative pliability of the crystals themselves, which is to say, their twistability.
Step 2: How do LCD TVs work?
How does a LCD (Liquid Crystal Diode) TV operate?
The Basics: 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.
Step 3: What are the advantages of LCD Displays??
Besides looking cool and oh-so futuristic in your living room, what are the advantages of owning an LCD TV or monitor?
It's easier to watch. Flat panel TV displays like LCDs and Plasmas are significantly brighter and feature higher contrasts than traditional CRT sets. Which means that an LCD TV will perform exceedingly well under most ambient light conditions. A brightly lit room won't wash out its picture, nor will lamplight cause a glare on your 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. Nor do you have to worry about eyestrain, since neither LCDs nor Plasmas flicker the way old-fashioned TVs do.
And, you can watch TV from almost anywhere in a room since flat-screen LCD television displays can have up to a 160° viewing angle, which means your TV will look good when viewed from any point 80° in either direction from the center of the display.
One issue affecting the overall quality of the picture reproduced on LCDs has to do with dot pitch. This term refers to the distance between subpixels of the same color in adjoining pixel triads. The closer these "dots" are to one another, the sharper the resolution will be. This is especially true when displaying computer signal images and graphs. And the picture in front of you will be more realistic and detailed. Higher dot pitches also increase the viewing angles of LCD panels. Since dot pitch is measure in millimeters (mm), a good rule of thumb is this: Smaller dot pitches make for sharper images. You generally want a dot pitch of .28mm [" 10,000 pixels/in2 of your display] or finer.
Note: Plasma TV displays have long been touted as having wider viewing angles than comparably sized LCD monitors. But recent improvements in quality have made LCD televisions and monitors comparable to Plasma TVs with respect to their viewing angles. According to Sharp, a leading manufacturer of LCDs, the newest generation of LCD displays have just as good viewing angles as plasma sets, but this is only true of the better brands. In any event, even the best LCD monitors have yet to achieve the breadth of viewing angles found on typical Plasma monitors.
Step 4: What do you need to consider before you buy your flat screen LCD TV?
Determine the right screen size based on your budget and your floor plan.
To get the most out of your investment, remember what your mother always said about sitting too close to the TV-that it's no good for you. Well, she might have been thinking about your health, but we're thinking about your viewing pleasure. For the optimal viewing experience, you need to maintain the right distance between your viewing area and your television screen.
Note: Some audio-visual critics have observed that fixed-pixel displays tend to show their pixel structures at closer viewing distances, so one might notice a sandy texture to the screen when the set is viewed too close. This underscores the importance of maintaining an appropriate viewing distance between you and your LCD monitor when configuring your viewing area.
The right distance depends on the size of your TV:
- For 20 to 27-inch displays, you should be able to watch comfortably from 2.5 to 5 feet away.
- For 32 to 37-inch TVs, you should sit back 6 to 8 feet from the screen itself.
- For 42 to 46-inch TVs, you'll need 10 to 14 feet between you and the screen.
- 50-inch LCD displays look best when viewed from 12 to 16 feet away.
Get the lowdown on HDTV compatibility.
If you're one of the 55+ million households sitting astride cable systems that can carry HDTV signals, your LCD TV will enable you to take advantage of the slightly better (10-15%) picture you can get from a higher resolution unit displaying HDTV broadcasts. Most LCD units come with built-in ATSC tuners, which enable them to pick up over-air HD broadcasts using antennas. In addition, manufacturers have begun packaging ATSC and cable tuners in LCD TV sets, making them optimal for watching HDTV-on local as well as national broadcasts.
Step 5: Installation Considerations
Determine how you're going to install your LCD TV.
LCD technology affords consumers new options when it comes to the physical placement of their TV displays. Gone are the days when you had to configure a room around the television set. Now, you can incorporate the TV into almost any décor, if you give a little thought to the matter beforehand. There are half a dozen ways to install your new LCD TV, which virtually ensures that you'll find the right way to fit one in your home.
You can mount your flat-panel display on almost any wall in your home.
- Flat Wall Mounts allow you to maximize the space-saving benefits of plasma technology. This option is generally the least expensive, and it adds just under two inches to the monitor's total depth.
- Tilt Wall Mounts enable you to place your TV above eye level, keeping it out of the way though readily viewable from anywhere in the room. This mounting option is typically used to install LCD monitors above fireplaces and in bedrooms. The tilt wall mount adds from 4 to 6 inches to the depth of the mounted display.
- Table Stands are another popular way to display LCD units. Realize, though, that these units are not one-size-fits-all appliances. Each display has its own custom-fitted table stand. Oftentimes one is included with the monitor itself; occasionally, though, you will have to purchase the stand separately.
- Articulating Wall Mounts make use of swivel arms to render the LCD unit flush with the wall-and out of the way-when not in use. Pulled out, this mounting device allows you to turn the display 120° to either side and as much as 10° up or down.
- Ceiling Mounts enable you to mount your TV where you want it-in the event that a wall isn't handy. This option is generally coupled with a tilt mount, so that the display can be adjusted downward for easier viewing. Lengths of ceiling mount poles vary according to customer needs, though the standard lengths are from 24 to 43 inches.
- Lifts There are a variety of lift options also available such as motorized ceiling lifts, console lifts, motorized furniture lifts and hydrolic furniture lifts. Lift options allow the plasma or LCD TV to be hidden from view when not in use. Hydrolic lifts are manually operated and less expensive while motorized lifts can be operated using remote control.
Step 6: Top LCD TVs
Choose your LCD unit.
What follows is a list of the best selling LCD display units, as compiled from data provided by vendors nationwide. For more information on one of these products, click on its name and model number.
Step 7: Where should you go to buy your LCD Television?
When buying your plasma display from an online dealer, be sure to get someone on the phone so that you can do some investigating.
(1) Find out if the company you're dealing with is an Authorized Dealer of the TV you're thinking about purchasing. Most Internet e-tailers are not authorized, which makes ones that are stand way out from the rest of the pack. Getting authorization to sell a given manufacturer's products is no easy process. Dealers have to meet some fairly stringent standards. Manufacturers usually require their dealers to offer technical support through a service center of some sort. In almost all instances, they will also require dealers to have a showroom for the product and a warehouse for the stock.
Internet companies that are not authorized retailers of the electronics they sell normally do nothing more than drop ship those products from distributors or other dealers. All of which means they have no way of replacing defective merchandise, getting spare parts, or handling returns. Nor can such dealers guarantee that the TV you get will be new, unopened, or unused.
(2) Ask, "What if…?" Imagine everything that could go wrong, and then ask a sales representative how his or her company would handle the situation. What if the LCD unit you receive is defective? What if your display goes bad after six moths? What constitutes a "defective" monitor? What if "x" number of pixels go bad within "x" number of weeks after getting your TV? Will they take the display back? Or, how can he or she guarantee you that your television will be repaired?
(3) Find out where they're located. Check the physical address of the company, and exclude those listing P.O. boxes or foreign countries as their addresses. You should also verify any address information with the Better Business Bureau (if the BBB insignia is posted on the website). Why? Because, if a dispute should arise, you need to be able to contact the company in writing.
(4) Determine whether they stock the products they sell. Many companies will claim to have a physical location, when they are really home- or apartment-based operations with little or no control over what happens once the transaction has been made. Always try to purchase from a dealer that buys direct from the manufacturer and stocks inventory.
(5) Ask whether they have corporate clients. If a vendor services other businesses, chances are, they're legitimate. You might also consider phoning some of these clients to confirm their references.
(6) Ask some technical questions about the products they sell. Make sure these people are competent enough to give you some after-purchase technical assistance should you need it.
(7) Get the low-down on the warranty. Inquire into the specifics of the dealer's return policy. It should give you one month's time to have any defective unit replaced at the seller's expense (shipping charges included).
You should also expect to pay some reasonable shipping fees. "Super saver" shipping is fine for books. But shipping a high-end digital television via the cheapest method possible will almost certainly turn into a major hassle down the road. In most cases, the costs of shipping are offset by the money you save by not having to pay sales tax on the purchase price of your plasma unit.
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