LED Televisions


This project is intended to discuss LED Televisions. The following are subtopics which should be researched in relation to this topic:



Definition

  • An LED is a flat panel LCD TV set that uses LEDs for its backlight source rather than fluorescent lights. An LED is a semiconductor diode that produces visible or infrared light when subjected to an electric current. LEDs consume little power and are long-lasting and inexpensive.



Specifications and Terminology


LED Specifications


  • The size of the LED TV depends on the brand
  • Samsung 4000 Series LED TV (available in smaller sizes also) range from 32’’ down to 19’’
  • The B8000 & 8500 is the” top of the line” this has only a 1 inch deep frame.
  • Samsung's 7000 series LED TVs with frames 1.2 inches in depth
  • The big difference that we noticed at CES 2010 in aesthetics was the much smaller bezel/frame which was only about 1 inch on top and sides of the TV screen.
  • The VF550M features a viewing angle of up to 178-degrees, resulting in a crisp and clear picture that is easily visible from just about anywhere in the room.
  • An LED backlight improves contrast and delivers a wider range of colors, for a more lifelike picture; consume less power than those with fluorescent
  • Some of these TVs use a series of LEDs arranged in a grid behind the LCD panel. And some TVs with these LED grids feature local dimming, which allows the TV to display light and dark portions of the same image more accurately
  • Other sets are "edge-lit," meaning that the LEDs are located around the sides of the panel instead of in a grid behind it
  • While edge-lit LED TVs don't offer local dimming, they generally have thinner cabinets — sometimes barely more than an inch deep.
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LED Terms

  • An LED is a semiconductor diode that typically emits a single wavelength of light when an electric current passes through it
  • Different colors can be generated based on the material used; common colors include red, green, blue, and white are used as a backlight in a newer LCD TV’s
  • Made of solid material such as silicon (electrical conductivity was great when hot and weak when cold)
  • Also known as electroluminescence
  • Semiconductors LEDs are made of slices of crystal (VERY thin) called lattice (most basic physical structure)


The History of LED

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Current Uses of LED


We don’t realize how many lights use LED’s. LED’s are used in many objects we use in our everyday life. LED’s are used are used for indicator lamps in many devices and are used in lighting things. The LED light has many different types of uses. LED lights make up nighttime lights, flashlights, pathway lights, task lights and exit signs.
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Flashlights are used to light up a small path in the dark. If the electricity goes out flashlights still work.
Nights lights are small lights to illuminate a room at night but only a little. It’s a small light so it is not pitch black in a room at night.
Path lights allow people to know where they are going. With the help of LED the lighting can be brighter. They are used on head lights of cars motorcycles and bicycles
They are also used in airports, aquariums, and parking garage lighting. LED lights in aquariums make the coral grow.
The task light is very important and has a lot of uses. A task light can be office lighting, school lighting, lamps, and desk lights. This allows bright lighting for professional settings. Here is a list of other ways LED lights are used today.
v Laboratory and electronic test equipment
v TVs
v Watches
v Radios
v Lightweight laptop displayscalcualtor_led.jpg
v Stage lightsstage_light.jpgprojector_led.jpg
v Calculators
v Street lightssecurity_cam.jpg
v Architectural lighting
v DCP projectors
v Airport runway lighting
v Cell phones
v Security cameras
v Telephones


How LEDs Work



LED TVs are made up of thousands of tiny Light Emitting Diodes. Each of these diodes is a semiconductor that contains a conducting material (aluminum-gallium-arsenide) and additional atoms that either add electrons or make holes where those electrons can go. These additional atoms allow aluminum-gallium-arsenide (AlGaAs) to conduct electricity better because the AlGaA atoms by themselves bond flawlessly and leave no free electrons that would allow electric current.

A semiconductor with extra electrons is N-type material (N for negative) while one with extra holes is called P-type material (P meaning it has extra positively-charged particles). As the N-type materials fill the holes in the P-type material, electrons jump from a higher orbital (the conduction band) to a lower orbital on an atom, which releases energy in the form of photons, or light.
Visible LEDs, such as the ones found in digital clocks and TVs, are made of materials that have a wider gap between this conduction band and the lower orbitals. This gap is what determines the color of the light emitted.semiconductor1.jpg



With the arrival of LED televisions, confusions involving them arrived along with them. LED televisions are still LCD televisions, but they have LED backlighting instead of the cold cathode fluorescent lamps which have been used unanimously in the past. The televisions still use LCD chips, but have LED backlights.

There are currently two main ways that LED backlighting is used in LCD televisions. There is edge lighting (edge-lit) and Full-Array lighting (local-dimming).
  • In edge lighting, LED’s are placed at the outside edges of the screen, and the light is then dispersed from the edge to the middle. This sometimes causes the edges of the screen to be brighter than the middle.
  • In local-dimming, LED’s are lined up in rows just inside the screen all across the screen. The LED’s can individually turn off, giving the contrast a boost because of the increase in contrast. You can get a much darker black and a wider control of brightness with this type of television. However, this type of television tends to be thicker than the edge-lit LED televisions



LED Versus LCDled_tv.jpg

LED


An LED consists of a chip of semiconducting material that with a p-n junction (positive and negative end). Like other diodes, the electric current flows from one end, the anode, to the other end, the cathode. The electrons run through the chip till the electron meets an electron hole. An electron hole is where a valence electron has recently left the valence band. When another electron meets the electron hole, the electron releases its energy in the form of photons; thus releasing the color of the LED. However, the color emitted by the LED depends on the semiconducting material wrapped around the LED.
There are several types of LEDs. Each one of them has a different use, power, and lifespan. One type of LED is the miniature LED. These LEDs are used as simple indicators. They do not last long because of their very simple design. Another type of LED is the Mid-Range LED, or the medium power LED. These LEDs are used in light panels, taillights, or emergency lighting. These LEDs boast a more intricate design. The medium strength LEDs come equipped with four leads that the diode rests on. (two anode and two cathode.) Finally, the high powered LEDs have a significantly larger design. However, this larger design has its drawbacks, because of their large design the high powered LEDs overheat very quickly. Because of this tendency to overheat, all high powered LEDs are mounted on a heat sink. These LEDs are used in many high powered lamps and flashlights.

LCD


Liquid Crystal Display (LCD) is a flat electronic visual display that uses the light modulating properties of liquid crystals in televisions. The Liquid Crystals don’t directly emit light themselves and are considered a passive display. LCD’s can be used for a number of things such as detailed still, non-moving images, or fast moving video. They are used in a wide-range of household items and everyday but are usually used in TV’s. LCD is also very useful because of its efSamsung_LCD_TV_sprejemnik_LE_37S81B.jpgficient power-saving properties although it is inefficient when the size of the screen is very large because of the amount of light needed to be produced at the back of the screen. It is also inefficient with power when it is bigger because on average only 8 to 10% of the light from the back of the screen reaches the viewer. This requires them to use several thousand watts of power which would normally be used to power a small sized house.external image moz-screenshot-2.pngexternal image moz-screenshot-3.png



However it is still an upgrade from previous CRT TV’s because LCD is available in much thinner and lighter sizes. It also is available in a much larger picture than before. Its low use of power when screen sizes are small allows it to be used in battery-operated items. Pixels in LCD consist of one layer of molecules aligned between two transparent electrodes, and two polarizing filters. The surface of the electrodes is used to align the liquid crystals in a certain angle or direction. Each individual pixel is divided into 3 sub pixels. One of the sub pixels is each a different color which are red, green, or blue. They are colored by using other pigment filters and white color filters. Each sub pixel is controlled independently which allows millions of possible colors for each pixel which is why LCD is so useful.


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Cables and Connections


LED televisions use different types of connections to receive and display data. The most common types are HDMI, P.C. connections, and HDMI-CEC. Each one of these has their own unique format and way of sending information.

HDMI Cables and Connections

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One of the main types of connections used for LCD televisions is HDMI, which stands for High Definition Multimedia Interface. Because of the amount of information that can be sent using HDMI, video and audio does not need to be compressed, resulting in better quality. HDMI does not need to compress its media because of the Digital, Analogue, Digital conversion process. It first converts the information into a digital format, and then transports it in an analogue format, and it is lastly converted into a digital format and then broadcasted on the television. A feature used commonly in HDMI is called Display Data Channel. This makes the connection scan the television used for its capabilities and adjusts the format of the data to best suit the television. HDMI most commonly uses cables to connect, the most common being a nineteen-pin cable called a form factor connector. This allows much more information to be sent to the television. This type of cable is simply referred to as Type A. A twenty-nine cable referred to as Type B can also be used, but it is not as common. There are also smaller ones used for handheld camcorders called Type C. That is how HDMI works and the cables used.

Connecting a P.C. to an LED Television


Computers and LED televisions have common interfaces. The most common interfaces are DVI on computers and HDMI interfaces on televisions. A DVI interface is a video interface that displays high quality on digital display devices such as a projector. A HDMI interface is an audio or visual interface used when transferring uncompressed data.how-to-setup-your-vga-to-hdmi-converter2.jpg

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First of all, before connecting a computer, one must see if there is a HDMI input on their computer. Next, set input in which the signal can be sent through on your television. The best inputs include VGA, component, DVI, or HDMI. After that, set a common resolution that you can use on your computer, if there is not, one can find that resolution and download it from the internet. If you are using a Mac, look for DisplayConfigXa on your computer. This is not easy because most HDTVs accept only a few resolutions, and many older HDTVs only contain component input. The best thing to do is to buy a new video card to hold more resolutions, or to buy a VGA to component converter. When getting a new video card, be sure to use the best driver. If you get a converter, then you will need a Powerstrip to set up the correct resolution. Do not be afraid to experiment with other resolutions to find the best match.

HDMI-CEC Connections


HDMI-CEC allows us to have remote controls that operate many different devices. CEC stands for Consumer Electronics Control. We can have remote controls that operate our televisions, video cameras, DVD players, Blu-ray players, and home theater systems. Using HDMI, we can control up to ten connected devices. To use HDMI-CEC, one must simply connect one A/V component to another via HDMI cables. Using the HDMI cables, one of the A/V components controls another A/V component. For example, inserting a disc into a DVD player would automatically turn on a television that is linked to it. HDMI-CEC initially only worked when components were from the same vendor, but HDMI-CEC now works across the products of different vendors. When hardware is compatible, any HDMI cable will work. This is because the technology is dependent on the connected sources and not the cable. The purpose of HDMI-CEC is to allow one-touch operation without intricate computer programming. Many believe that this innovation has moved us in the direction of simplicity. There are problems with HDMI-CEC though. Like many other innovations using HDMI cables, there are issues with incompatibility between devices. Terminology can also become
complicated due to the varying brand names for HDMI-CEC. LG uses the name “SimpLink”, Panasonic uses “EZ Sync”, Toshiba uses “CE-Link”, and Samsung uses the name “Anynet”. HDMI-CEC is a specification of HDMI that has received a lot of attention.

Benefits


LED televisions have many benefits as opposed to the average standard television. First, they last longer. In other televisions, the light bulbs tend to degrade over time, while this does not occur in LED’s. This mainly comes from recentness of the technology. The newer it is, the more advanced it is. Another benefit of the LED is that is it better for the environment. It consumes less energy than a majority of televisions, but this does not mean that the quality is inferior. They are just as bright, if not brighter, than other televisions. Also, they do not use dangerous mercury for the lighting. The energy consumption is almost fifty percent more efficient. The quality of an LED television is good in many aspects. Unlike fluorescent lighting, the diodes can be turned off, creating a darker and richer black. The color is sharp and realistic. The contrast ratios are especially good due to the cultra_thin_tv.jpgapability of true black and intensely bright lighter colors. The new technology of an LED television allows it to change color more often and in a shorter period of time. This also creates a more realistic picture, and reduces blur in fast motion scenes. Its interpolated frames, or frames which produce more images by showing images between frames, allow for a 120 Hz refresh rate. A more obvious benefit to an LED television is the depth. They are extremely flat, and therefore, lighter and easier to manage.



LED Television Brands

Samsung Televisions are one of the best LED televisions out on the market. They are also one of the most expensive. The 46” LED TV is only 1.2 inches thick. Although it has a great picture, the off angle viewing of this television is not that great, but if viewed from the front, this television produces a great picture with the greatest colors and the deepest blacks. Finally, the Samsung televisions have interactive features.
Similar to the Samsung, LG televisions are also very expensive. LG and Samsung are among the top LED television brands out there. They are great televisions, except they do not include a lot of features. They lack interactive features and an S-video input. Despite this LG televisions are great if you are just watching television.

Vizio televisions are a great value. The picture is as great as some of the other televisions, but they are more affordable. They produce deep blacks, but they do no have very good shadow detail. They have many ports for accessories and even a PC port. In the end, Vizio televisions are good buys that produce a good picture.
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Sony LED televisions are probably the best LED televisions out on the market. The only problem is, they are also the most expensive. They have four HDMI ports and a PC port. There are interchangeable speaker grilles on this television. The Sony produces the best picture of all of the television. It also has the best picture in a bright room. Because of this, it is probably the most user friendly because most people do not want to have to turn their lights off every time they watch television.

Similar to Vizio, Toshiba also has a great value. They do not have very good picture, but they have a great value. The backlight fluctuates and you get a shadow on the television. Despite this, they have a very adjustable picture. So in the end, if you want to buy a Led television and you do not have much money this is the television for you.


Future Uses of LED Televisions


Due to technical advancements, we now have LEDs. LCDs and plasma screens.
If the emitting layer of the LED is made up of an organic compound, it is known as an organic light emitting diode (OLED). The emitting material can be a small organic molecule in a crystalline phase, or a polymer. Polymer materials can be flexible; such LEDs are known as PLEDS or FLEDS. OLEDs are lighter than LEDs and polymer LEDs can have the benefit of being flexible. OLEDs could bring many different aspects to television, including:

  • Inexpensive, flexible displayslumitable-fiber-table-cloth.jpg
  • Light sources
  • Wall decorations
  • Luminous cloth
A new development of LED television includes coating a LED light with quantum dots that glow white in response to the blue light from the LED. It produces a whitish yellow light similar to an incandescent bulb’s light.
Another type of LED televisions is 3D LED. Samsung will be the first company to release the 3D LED TV in 2010. It’s going to be called the LED 9000, including a 3D processor. It will have a 240MHz. It is also going to be the thinnest LED ever 0.3 inches (7.6 mm) thick Also, Samsung has included a computer chip with auto-conversion technology, converting TVs from 2D capabilities to 3D capabilities. They will be available in sizes of 46 and 55 inches.


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