Purchasing a television represents a significant expense for most households. Therefore, it is important for a buyer to do some research be shopping for a new television. Resolution is one of the most important considerations when buying an LED TV, but it can also be one of the most confusing. This guide begins by covering the basics of LED TVs. Then, the guide defines resolution in terms of displays and sources, aspect ratio, scanning, and scaling. The guide closes with a discussion on how to find an LED TV on eBay.
The Basics of LED TVs
An LED TV is a specific type of LCD TV. LCD stands for "liquid crystal display." It is created by sandwiching liquid crystals, which is actually a gel-like material, between two panes of glass. Liquid crystal has a twisted molecular form that will untwist in predictable ways when electrical current is applied to it. LCDs are usually transparent, but when current is applied, the light is bent and only some light will pass through the top layer of glass. In some instances, no light passes through. This is how different shade of color are produced on a screen. To create colors, small filters in red, green, and blue are placed over the top pane glass. Each grouping of the three colors is called a pixel. It is the pixels that when combined create images on the screen. LCDs cannot create light on their own. They need a light source to shine through the back of the glass, and in some cases along the edges of the screen. Older LCDs were lit using fluorescent lamps. Now, many LCD televisions are lit by LEDs.
LEDs and Lighting TV Screens
An LED is a diode that creates light by vibrating electrons within a semiconductor. LEDs have the advantage of being brighter, more energy-efficient, and smaller. There are two types of LED TVs. A backlit LED TV has LEDs placed throughout the rear side of the LCD display. This allows the brightness to be controlled throughout the entire display and creates richer contrast and vivid colors. An edge-lit LED TV has LEDs placed along the entire perimeter of the display, but not in the middle. In addition to providing increased colors and contrast, edge-lit LED televisions are incredibly thin and lightweight, making them easy to move or mount on walls.
In its most basic sense, resolution is a measurement of pixels. However, the impact that resolution has on a television's picture quality goes far beyond just the number of pixels. The native resolution of the source, aspect ratio, type of scanning, and scaling all affect the sharpness and quality of the image on the screen.
Display resolution is a measurement of the pixels on the physical screen. This is also called native resolution. This is generally presented as width x height. Because LED screens have a certain number of pixels, they are called fixed-pixel displays. This means that even when receiving information from the source, the native resolution is the maximum detail that can be shown. Likewise, when a video signal with lower native resolution is sent, it is enlarged to fill the entire native resolution. HDTVs are often classified by another number to indicate resolution. These numbers are 1080p, 1080i, and 720p. The numbers refer to the height of the screen, while the letter refers to the type of scanning the television uses.
Source resolution should match up with an HDTVs native resolution. This is a measurements of the source resolution and are referred to by 1080p, 1080i, 720p, 480p, and 480i. Neither 480p or 480i are high-definition signals. 1080p is the highest resolution and Blu-ray players, some gaming consoles, and some video-on-demand and Internet sources have this resolution. 1080i and 720p are two high-definition signals that are used by networks when broadcasting an HD signal. 480p and 480i are standard-definition source resolutions. These are used in DVD players and any standard-definition TV broadcast.
Aspect ratio is a number that describes the ratio of the width of a display to its height. The two main aspect ratios used in televisions are 4:3, or standard, and 16:9, or widescreen. Broadcast signals are transmitted in both of these formats, however, the trend is moving towards using 16:9 aspect ratios. Each aspect ratio has its own advantages. A 4:3 aspect ratio is what most standard definition broadcasts are ouput in. This is the same for older films, VHS sources, and many DVD sources. The widescreen, 16:9, format is the standard for high-definition output. Most movies today are shot with a 19:9 aspect ratio, and many DVDs, along with all Blu-ray movies, use this format. For the best picture quality, it is important to match the aspect ratio of the television and of the incoming signal whenever possible. Each television format can display both types of signals, however the picture will modified. For instance, when a 4:3 television plays a 16:9 signal, one of three things happens. First, a section of the picture is cut out to fill the screen, eliminating two sides of the image. This loss of detail can sometimes have a real impact on the viewing experience. Second, the display can be stretched, which distorts the image and provides a picture that does not match the original. Third, and most commonly, the signal will be "letterboxed." This simply means that black bands are placed above and below the image, allowing the entire picture to be shown. However, the image is smaller than if it were covering an entire screen, so detail is lost. The same is essentially true of a 16:9 television playing a 4:3 source. It can be stretched, cut and zoomed in, or black bands placed to the right and left. This is why matching aspect ratios is ideal and provides the highest quality viewing experience.
Interlaced and progressive scanning are the two types used in television. Scanning is simply the name for how a screen updates and changes its image. This is what the "i" and "p" stand for when naming source and native resolutions. Interlaced scanning splits the screen into two fields: one for the odd numbered lines and one for the even numbered lines. These are refreshed at a rate of 60 fields per second, with the first field following the second and then repeating. This creates a frame rate of 30 frames per second. This means the image on the screen can change 30 times in every second. Progressive scanning refreshes the entire frame in each cycle. This means it has a 60 frames per second frame rate. So, in each second, a television or signal using progressive scanning can update the picture 60 times in a second, double that of interlaced scanning. This provides a higher quality and sharper picture. It is especially noticeable in scenes with a lot of motion, as interlaced scanning will sometimes show a blur as objects move quickly across the screen. Progressive scanning reduces or eliminates this motion blur.
When the native resolution and source resolution do not match, an image is scaled to match the native resolution of the television. For instance, when watching a Blu-ray movie, which has a source resolution of 1080p, on an LED TV with a native resolution of 720p, the signal will be downscaled to 720p. Some of the details in the image will be lost, though it will still be high quality. On the other hand, when watching a show broadcast in 720p on a television with a 1080p native resolution, the image will be upscaled to 1080p. Additional pixels cannot be added to source image, but the detail is effectively doubled, allowing it to appear larger. Again, this does not have a huge impact on the picture quality, though it can make the shortcomings in a low quality source more apparent. Some televisions will have an option to avoid scaling altogether and displaying images just as they are. This is called 1:1 pixel mapping. Images from a lower quality source will have black bands around them, similar to letterboxing, while higher quality sources will be centered on the screen but not display the entire picture.
Considering Resolution When Buying an LED TV
Beyond the specific aspects of resolution, a buyer should consider screen size and viewing distance whenever choosing a new LED TV.
The Screen's Size
The larger the screen is, the more detail it will show. So, the larger the screen, the higher the the resolution must be to maintain optimum picture quality. Unless the quality of the source is very bad or the screen is very large, all the HD resolutions generally look about the same.
How Far Is the Viewer from the Screen?
The viewing distance is another important factor to consider when decided what resolution a new television should be. The closer a viewer sits to a television, the more detail they will see. Therefore, resolution should be higher the closer a viewer sits to the TV set to ensure the best viewing experience. These two elements both affect the perfect resolution for any situation. To get a noticeable benefit from 1080p resolution, the viewing distance should be less than one and a half times time diagonal measurement of the screen. For example, to notice the difference in quality of an image on a 40-inch 1080p screen, the viewer must be sitting five feet or less from the screen.
Saturation and Contrast
Instead of giving resolution all the weight when deciding on an LED TV, contrast and color saturation should considered. The design and lighting of LED TVs tends to provide enhanced contrast and more vivid colors than other LCD screens. However, each brand of television may represent colors slightly different. There is nothing wrong with this and it is really a matter of preference. For this reason, it is a good idea to get a look at the screen, even if in a different size, before purchasing.
How to Find an LED TV
LED televisions can be found in most electronics and department stores. They are often set up for viewing so that a buyer can compare their picture with other televisions, along with getting a feel for the overall dimensions of the television. Additionally, LED TVs can be found on many websites online, including manufacturer's websites and online auction sites like eBay.
Buying LED TVs on eBay
It is simple to find LED TVs on eBay. Start with a search from the search bar on the homepage, or browse through the categories for more choices. To start, select the Consumer Electronics category. Then, select Televisions. Using the menu on the left, select LED LCD from the display technology section. At this point, the results can be narrowed by several options, including screen size, resolution, brand, and price.
One of the best things to do when purchasing online is to get to know your seller. eBay makes this simple by providing a feedback profile for every user. The feedback score, which is actually shown in parentheses after the username whenever it is shown, gives a snapshot of the number of successful transactions the seller has had on eBay. Each transaction can be rated. Positive transactions add one to this score, while negative ratings subtract one.
The feedback profile provides much more information on a user. It contains a charts of recent feedback ratings, showcasing the number of positive, neutral and negative ratings. It also has a list of detailed feedback left by previous buyers.
When trying to choose a new television, resolution can be one of the most important and most confusing elements to understand. The way a television's native resolution and aspect ratio work with those of a given source really determine the quality of picture a buyer can expect to see. LED TVs have advantages over others in that they are very energy-efficient, lightweight, and thin. This makes them perfect for wall mounting or in any situation where they would need to be moved often. Additionally, the LED backlighting of the LCD display creates high contrast and vivid colors for a picture quality that's amazing. These televisions can be found for a great price in both brick and mortar stores and online, including on eBay.