As we all know, you need to press a button to read a watch in the dark, and an LCD TV is no different. It needs a light behind it because it emits no light of its own. It's helpful to think of an LCD panel as a sandwich, consisting of different layers. On a typical TV you have a polarised filter, followed by a protective glass layer, followed by the LCD sheet, and then a light source at the back.
CCFL backlighting consists of a series of tubes laid horizontally behind the screen. Though there are several different ways of backlighting using LEDs as we'll explain shortly , the idea is the same: a series of LED bulbs throw light from behind to illuminate the LCD panel. There are two different methods of LED backlighting: direct and edge.
The main advantage of direct lighting is that it can be used to increase contrast levels by turning some LEDs off — thus increasing the amount of black in parts of the picture. LG is one of the champions of direct lighting. In comparison, edge lighting's main advantage is that it can be used to make screens that are incredibly thin — the LEDs are at the side and not behind the screen.
Of course, you lose the ability to switch off parts of the backlighting for better contrast, and picture quality could also suffer if light isn't sufficiently well dispersed. When using LED backlighting, there are several different coloured ones you can use, but the two main options are white and RGB.
But the LEDs aren't actually white; this approach uses a blue light source that is made to look white by the presence of a sulphur coating on the bulb. CCFLs work in the same way. LED backlights generally come in two varieties: edge or direct also sometimes referred to as full-array. Broadly speaking, a direct LED backlight can go brighter and offer better contrast, but even the most advanced examples boast only around LEDs that between them handle the lighting of the 8,, pixels of a 4K display.
In other words, even the best LED backlight can't match an OLED for close contrast control, although Samsung's flagship sets get much closer than you might imagine possible. Think of these as being like OLEDs that can go much brighter and don't suffer image retention and you're on the right lines. Created along with plasma to replace the huge CRT cathode ray tube televisions of old, LCD liquid-crystal display TVs have a panel of liquid crystals through which light from a backlight is shone.
Compared to what had gone before, LCD TVs were lighter, thinner, brighter, more colourful and cheaper to produce, but early examples in particular regularly struggled to produce deep blacks and convincing contrast. These days, though, there are lots of very good LCD-based TVs around and many represent exceptionally good value the Samsung UE49RU is one of the best performance-per-pound televisions you can currently buy , but there's no denying that OLED is better.
Tom Parsons has been writing about TV, AV and hi-fi products not to mention plenty of other 'gadgets' and even cars for over 15 years. He began his career as What Hi-Fi? In between, he worked as Reviews Editor and then Deputy Editor at Stuff, and over the years has had his work featured in publications such as T3, The Telegraph and Louder.
Comparison chart Differences — Similarities —. Picture Quality Even though some say the picture quality of an LED TV is better, there is no straight answer for which has better picture quality since both TVs use the same kind of screen. Full-array LEDs where LEDs are arranged behind the screen as a set, but are incapable of dimming or brightening individually.
Front projection LCDs or projectors, which project an image onto the front of the screen. The TV itself is just a box installed anywhere in a room, which projects the image onto a flat screen hung on the wall as large as inches. Rear projection LCDs are wide, heavy and only available in large sizes 60" and up. Follow Share Cite Authors.
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