LED vs. LCD TVs explained: What’s the difference?

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Creating or upgrading a home theater setup often comes down to one major question: What kind of TV should I get? While there are several types of TVs, two terms come up pretty often: LED TVs and LCD TVs.

But what’s the difference? It’s a question we hear a lot from budding home theater shoppers, but shouldn’t. Blame the acronyms. Here’s the quick answer: An LED TV is an LCD TV, but how the two came to be confused with each other might come as a surprise.

Once you’ve got a better grasp on LED and LCD technologies, check out our QLED vs. OLED post to find out about the latest TV tech, as well as our list of the best TVs you can buy for suggestions of our favorite picks from what’s currently available

An LED TV is an LCD TV

Despite having a different acronym, an LED TV is just a specific type of LCD TV. The proper name would actually be “LED-backlit LCD TV,” but that’s too much of a mouthful for everyday conversation, so people generally just refer to them as LED TVs.

Both types of TV make use of a liquid crystal display (LCD) panel to control where light is displayed on your screen. These panels are typically composed of two sheets of polarizing material with a liquid crystal solution between them, so when an electric current passes through the liquid, it causes the crystals to align so that light can (or can’t) pass through. Think of each crystal as a shutter, either allowing light to pass through or blocking it out.

Now, since both LED and LCD TVs use LCD technology, you’re probably wondering what the difference is. Actually, it’s about what the difference was. The LCD TVs you think of now no longer exist. Here’s why: Backlighting. Older LCD TVs used cold cathode fluorescent lamps (CCFLs) to provide backlighting, whereas LED TV’s used an array of smaller, more efficient light emitting diodes (LEDs) to illuminate the screen, which gave them a few advantages. Now, all LCD TVs use LED lights and are colloquially considered LED TVs. Here’s how that works.

Backlighting

There are three different forms of illumination that have been used in LCD TVs: CCFL backlighting, full-array LED backlighting, and LED edge lighting. Each of these illumination technologies is different from one another in important ways, and each has pros and cons. Let’s dig into each.

CCFL Backlighting

CCFL backlighting is an older form of technology that has mostly been abandoned, though some manufacturers do use CCFLs in lower tier LCDs since they’re cheaper to make. A series of CCFLs sit across the inside of the TV behind the LCD display. The lights illuminate the crystals fairly evenly, which means all regions of the picture will have similar brightness levels. This affects some aspects of picture quality, which we discuss on the next page. Since CCFLs are larger than LED arrays, CCFL LCDs tend to be thicker than their LCD counterparts. As this is an outdated technology, you won’t find many models using this style of illumination. A few tend to crop up here and there, but they’re almost always on the cheaper end of the spectrum.

Full-array backlighting

Full-array backlighting swaps the outdated CCFLs for LEDs. An array of LEDs spans the back of the LCD screen, with zones of LEDs can be lit or dimmed in a process called local dimming (we go deeper into how local dimming works on the next page). TVs using full-array LED backlighting make up a chunk the high-end LCD TV market, and with good reason — with more precise and even illumination, they can create better pictures than CCFLs LCD TV were ever able to achieve. Plus, they’re less of a power drain than CCFL LCDs were. Given these benefits, the shift to LEDs as industry standard made a lot of sense.

Edge lighting

Another form of LCD screen illumination is LED edge lighting. As the name implies, edge-lit TVs have LEDs along edges of a screen. Within this lighting type, there are a few different configurations, including LEDs along just the bottom; LEDs on the top and bottom; LEDs left and right; and LEDs along all four edges. These different configurations result in differences in picture quality, but the overall brightness capabilities still exceed what CCFL LEDs could achieve. While there are some drawbacks to edge lighting when compared to full-array or direct backlight, the upshot is edge lighting allows for manufacturers to make thinner TVs which cost less to manufacture.

To better close the local dimming quality gap between edge-lit TVs and full-array backlit TVs, manufacturers like Sony and Samsung have developed their own advanced forms of edge lighting. Sony’s technology is known as “Slim Backlight Master Drive,” while Samsung has “Infinite Array” employed in its line of QLED TVs. These keep the slim form factor achievable through edge-lit design but with local dimming quality more on par with full-array backlighting in these cases (though still not quite equal).

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