Television is the literature of the illiterate…culture of the low brow…the exclusive club of the excluded masses… this amazing magic box passed through several stages and now 100 million TV sets are sold each other…

 

Coming to our present topic: LED TV…

A light emitting diode, shortly called LED is a semi conductor light source are used as indicator lamps in many devices…When an LED is forward biased (switched on), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor….

LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability.

 

But what brings a relation between TV and LED?

First of all let’s see about LCD…Liquid-crystal display televisions (LCD TV) are television sets that use LCD technology to produce images. Standard LCD TVs aren’t known for excellent contrast ratios since they use cold cathode fluorescent lamps (CCFLs) which can’t be turned off while in use. This means they can’t produce rich dark images because there is always light on the screen.

Because LCDs were used for data display that did not require fast refreshing rates they did not have a fast refreshing rate. Fast moving objects on the screen will look awkward and mechanical since the screen cannot keep up. This means that fast moving scenes will look good and is true until you get to screen sizes over 35.

The main advantage of LED is that irrespective of its size and shape they produce same amount of light per density… where as in CCFLs, display light depends on the intensity and size of the screen…

A LED-backlight LCD television is an LCD TV that uses LED backlighting other than the cold cathode fluorescent lights used in LCDs…It is not a true LED display but is often called “LED TV”…The LEDs can come in three forms:

DYNAMIC RGB LEDs which are positioned behind the panel, WHITE EDGE LEDs positioned around the rim of the screen which use a special diffusion panel to spread the light evenly behind the screen (the most commonly used) and FULL-ARRAY which are arranged behind the screen but they are incapable of dimming or brightening individually….

 

LED BACKLIGHTING TECHNIQUES USED:

RGB dynamic LEDs

This method of backlighting allows dimming to occur in locally specific areas of darkness on the screen. This can show truer blacks, whites and at much higher dynamic contrast ratios, at the cost of less detail in small bright objects on a dark background, such as star fields.

Edge-LEDs

This method of backlighting allows for LED-backlit TVs to become extremely thin. The light is diffused across the screen by a special panel which produces a uniform color range across the screen.

Full Array LEDs

Many brands use LED backlighting technology and may offer a range of benefits over CCFL LCD TVs such as reduced energy consumption, better contrast and brightness, greater color range, more rapid response to changes in scene and a capacity to provide the means to render an image more accurately.

Coming to advantages of these ultra cool models…

Standard TVs refresh at 60Hz, and the best LED TVs refresh at 240Hz or faster. You will also want to look for a TV with a response time of 3ms or faster. This will make those quick movements less blurry and improve gaming, sports and action movies. Because of the LED backlighting you will find TVs with a contrast ratio of up to 10,000,000:1, which is far beyond that of any LCD TV on the market.

LCD-based televisions described as ‘LED TVs’ are vastly different from self-illuminating OLED, OEL or AMOLED display technologies. And an LED backlight enables the machine to use 20-30% less power, Furthermore; LED TVs are also free from any mercury content so it is the more environmentally friendly option.

Now a days Sony Ericson started using OLED screens through which image can be viewed even from 170degrees…cool na…


 

Courtesy: Wikipedia, LED HDTV

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