What is the difference between led backlit lcd and led

A Liquid Crystal Display LCD is one of the most enduring and fundamental technologies found in monitors, televisions, tablets, and smartphones. TVs and monitors once used cathode ray tubes CRTs to provide the image on your screen.

But CRTs were bulky and contained dangerous chemicals. An LCD features a panel of liquid crystal molecules. The molecules can be induced using an electrical current to take certain patterns which either block or allow light to pass through. To provide a color image on your screen, the LCD has red, green, and blue sub-pixels in each screen pixel. Transistors within the display control the direction of light each pixel emits, which then passes through either a red, green, or blue filter. You should know about screen burn-in with LCD monitors so you can avoid damaging them.

Light Emitting Diodes LEDs are small semiconductors that emit visible light when an electrical current passes through them. LEDs are typically more efficient and longer-lasting than traditional lighting.

The LEDs give better control of the light, as well as greater efficiency as it is possible to control individual LEDs. That's not to say there aren't differences between the two. However, both LED and LCD monitors have different technologies that make certain panels more appealing to gamers, film buffs, designers, and so on.

You should also note that on older screens, the difference between an LCD and LED TV or monitor is more pronounced, due to the relative age of the two lighting options. When you're trying to buy a new TV or monitor, understanding the differences and the terminology will help you bag a better deal.

The Edge-Lit option allows for slimmer designs, uses fewer LEDs, and can bring the cost of a new screen down. Light reflects across the screen uniformly to create the image. One downside to an Edge-Lit screen is the dark contrast. Because the Edge-Lit LED display is brightest closer to the edges, color uniformity and black levels can become an issue, with some areas appearing darker than others. Local dimming means that groups of LEDs can switch on and off as required to provide better overall control of the brightness level.

LEDs are often referred to as emitting white light. Actually, LEDs produce light closer to yellow than a pure white. That difference can create a color shift in the image you see on your screen. Forrest Hartman is a former Lifewire writer and an educator and journalist who focuses on television and related technology for Gannett News Service and other outlets. Updated on July 28, Ryan Perian. Lifewire Technology Review Board Member. Article reviewed on Oct 15, Tweet Share Email.

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Tell us why! More from Lifewire. Imagine a night landscape with a bright full moon. Ideally, the moon is bright, and the rest of the scene is dark. So in most cases, everything below the moon in our example would be brighter than the surrounding image. Here's a Photoshopped and exaggerated demonstration of what this can look like.

Top and bottom As you can guess, this design has LEDs on the top and bottom edges of the screen. The local dimming here is a little better, where the zones can be slightly smaller areas of the screen, like this:. As you can see, there's still some areas lit that shouldn't be, but it's a lot better. The idea with local dimming is you want as small and precise an area as possible ideally, per-pixel, but that's not feasible with current technology.

Remember, it's hardly ever going to look this severe, I'm merely illustrating the point so you can see it. Left and right The alternative to top and bottom. LEDs on the sides. Local dimming is similar to top and bottom. With the better TVs, there are few artifacts like these images. Instead, the processing errs on the side of safety, not allowing adjacent LEDs to get too different in brightness, so as not to have issues like you see here.

The flip side of that is less "punch" in the image, as bright objects on an otherwise dark background don't appear as bright. All sides This is a less common method now, as it requires more LEDs than any of the other edge-lighting methods. The local dimming can get a little more accurate, but is still limited to large-ish zones.

If we used our moon example image, the result with an all-sides edge-lit would look just like top and bottom. But with regular video that has more light sources than just the moon , it will have a more zones to work with, sort of like this:. All Sides used to be the most common edge-lighting method. But as the light guides improved, and costs had to come down to make cheaper LED LCDs , this method became fairly rare.

The LEDs are arrayed on the back of the TV, facing you, but there is no processing to dim them individually.