With Diwali just around the corner, it's time to hit the stores to pick up everything that you might have been saving up for.
And if you have been eyeing that brightly lit, size zero display at the local electronics store but are confused by all that advertising blitzkrieg about LED and 3D TVs, allow us to enlighten you.
The big-wigs in the display game like Samsung, Sony and LG have managed to grab your attention with their larger-than-life ads for their new ‘LED' television displays, but here are a couple of things you should know about LEDs, before you shell out the big bucks.
Some ‘unlearning' first! LED TVs, as you might have been led to believe, are not truly LED (Light Emitting Diode) displays but are, in reality, LCD ones. The difference between a regular LCD and an LED TV lies in the ‘backlighting'. What's that, you ask? Here's a low-down.
Remember the digital watch you had as a kid or the scientific calculator that you dad gifted you? The display on those were LCD displays too! The only difference being, that those weren't backlit, unlike TV sets that adorn our living rooms today.
LCD displays are based on liquid crystals, which are particles that can arrange and re-arrange themselves in response to an electric current. Each crystal can act like a shutter either allowing light to pass through or blocking the incoming light.
One LCD panel constitutes millions of such liquid crystals arranged in a grid to let a backlight through and create images. As a source of backlighting, regular LCD TVs use fluorescent bulbs, technically known as CCFLs (Cold cathode fluorescent lamps). These had succeeded CRT television sets that were bulky and created pictures that were far from stunning.
The LED TVs that are being portrayed as larger-than-life displays in ads now, are an improvement on the existing LCD TV technology and are not truly a brand new technology altogether. Hence, LED TVs are actually just another type of LCD displays.
These are called LED TVs because, instead of the CCFL bulbs, a panel of Light Emitting Diodes or LEDs are the source for the backlight for these LCD TVs.
Why the replacement?
CCFLs are significantly more cost-effective for bigger displays like a TV set but when it comes to the overall picture quality, contrast ratio, colour gamut and power efficiency, LEDs can deliver better. This has prompted all major manufacturers to turn to the new lighting kid on the block.
Types of LEDs
There are two-types of LED TVs based on how they provide the backlight for the LCD display.
Backlit / Full array LED – Backlit or full-array LED TVs are made up of LEDs grouped in ‘blocks' and placed behind the LCD panel in the display. These blocks of LEDs can be switched on or off independently of each other. This ability, popularly known as local dimming is exclusive to backlit LEDs and results in a much improved contrast ratio than a traditional LCD or even an edge-lit one.
Edge-lit LED – Like the name suggests, the LEDs on these sets are arranged only along the edge of the LCD panel but a ‘diffusion' panel allows for the light to be distributed evenly throughout your TV set.
Owing to the fact that this kind of display requires the LEDs to be placed only at the sides of the unit, it paves the way for manufacturers to build a set so slim that it would give size-zero models an inferiority complex.
Edge-lit LEDs also score when it comes to power efficiency. Compared to the conventional LCD TV and even a backlit LED, an edge-lit consumes much lesser power.
Television setup
Apart from the LCD panel, an LED TV has a couple of other layers or panels that constitute the display.
One panel consists of ‘diffusers' that ensure uniform brightness throughout the screen and ‘polarisers' that sandwich the LCD panel to make sure that the picture relayed is aligned correctly.
Depending on the manufacturer, there might be another layer of anti-glare coating apart from the main display.
You have a light source behind the liquid crystal panel that shines light through the display.
Even when it comes to LED backlights, there are two categories of backlighting possible.
White LEDs – These LEDs aren't actually white but a combination of blue LEDs and yellow phosphor that give the impression of white light. Most edge-lit LED sets use this technology with the light diffusing panel behind the LCD panel to redirect and scatter the light in a way to ensure an evenly lit image.
RGB LEDs – Owing to the fact that these LEDs work on the basis of all three primary colours, the colour rendered on the screen is way superior. The colours are deeper and more realistic than those produced by white LEDs. This makes most television manufacturers to go for RGB LEDs in their high-end LED-backlit television sets.
Why does LED score?
Contrast – This parameter is usually denoted by a ratio of the brightest white to the darkest blacks that can be displayed on the screen. When it comes to contrasts, LEDs trump CCFLs because of their ability to ‘dim' locally thus allowing the screen to show both light and dark details as well as possible, resulting in an improved on-screen contrast.
Form factor – While the average thickness of LCD TVs could be anywhere between 6-inches to about 2-inches, LED TVs, especially edge-lit ones are extremely sleek and space-efficient; apart from being easy to move around and wall-mountable owing to thickness that can be as little as 7-8 millimetres.
Plasmas
Plasma TVs are based on electric current being made to pass through neutral gases to produce colour and consequently, images. These gases are trapped between two plates of glass and offer very bright, crisp images, even on a large screen surface.
However, one factor that Plasma TVs lose out on is burn-ins or dead pixels. Due to the inherent technology that Plasma TVs work on, the chances of the display getting a burn-in are present while no such thing can happen with an LED TV set as they work on a completely different technology.
Plasma screen, on the other hand, deliver amazing reproduction quality for fast-moving videos and are ideal for watching sports and movies.
Adding to this, Plasma TV sets do not suffer from motion lags or ghosting while displaying fast moving images, a common issue with LCD TVs especially in those with larger screen size.
Moolah talk
When it comes to display sizes, LED TVs can range from anywhere between 22-inches to 55-inches. The price obviously differs depending on the manufacturer, but on an average, an LED TV can cost you a minimum of about Rs 20,000 and can go up to Rs 2.5 lakh for a 55-incher.
The low-end models would be ideal for a bedroom setting but might not have the capability to playback high-definition content. On the other hand, if you have a living room to adorn a mammoth LED TV with or are planning to set it up in your home theatre, you could go with a big-screen one that will also provide you with Full HD or even 3D capabilities.
