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What is an LED Backlight LCD TV?

Gregory Hanson
Gregory Hanson

An LED backlight LCD TV is a flat screen television in which a front liquid crystal display (LCD) panel is illuminated by an array of light-emitting diodes (LEDs). Flat screen televisions and computer monitors require some form of rear illumination, so that the image displayed on the LCD panel will be visible to a viewer. Early LCD televisions and monitors employed other types of lighting, often high-power fluorescent bulbs. LED backlight LCD TV screens, however have several advantages over earlier versions of flat screen technology, including power consumption, brightness and lifespan.

LCD monitors and televisions work by filtering white light from a background source, allowing only the colors needed to produce the image on the screen to pass through and be visible. This process is not very efficient, and the majority of the light produced in an LCD TV is filtered out, leading to high power consumption. LED backlight LCD TV is more energy efficient than earlier flat screen television technologies, in large part, because each LED is responsible for illuminating only a very small portion of the screen, and each LED needs to generate light only when that area of the screen needs to show an image and only at the level of brightness necessary for the image being displayed. This characteristic of LED backlight LCD TVs reduces waste light and heat generation.

An LED backlight LCD TV.
An LED backlight LCD TV.

An additional advantage to high-quality LED backlight LCD TV is their longer average lifespan. LEDs are very simple and durable products, if manufactured properly, and can provide years of reliable service. Flat screen televisions backlit with high-power fluorescent bulbs are prone to failures related to their illumination systems. LEDs, on the other hand, if produced to an appropriately high standard, are less likely to fail before other elements of a LED backlight LCD TV. Individual LEDs do eventually fail, and the failure of LEDs can produce dead spaces in an LCD TV screen where the pixels are no longer illuminated.

More advanced technologies similar principles to LED backlight LCD TV are possible. Organic LED technology fuses the two key components of a flat screen TV. In such devices, the LCD panel that creates the image for display can also directly emit light. This is a significant advantage because no energy needs to be wasted generating light in portions of the visible spectrum that will be filtered out by the display panel or in illuminating darkened areas of a screen.

Discussion Comments

SushiChamp

LED backlighting is great, but it has some problems. Over time, some of the LEDs can age faster than others, causing the colors in some spots of the screen to become distorted. Sometimes high temperatures will lead to blue shifts in white LEDs, resulting in poor color quality. I’ve never had a problem with any of my TVs or monitors, but that might be because I only buy the smaller ones. A 32” LCD TV contains more LEDs and might therefore be more prone to color shifting.

parklinkz

@kangaBurg – The best LED LCD TVs use RGB backlighting. The three colors (red, green, and blue) are combined in varying shades of white, and help to create lifelike, bold hues that are far superior to those produced with white LEDs. At first, it may seem like a white LED would produce better results, but what we call “white” in the world of LED backlighting is actually a blue LED with a yellow phosphor.

Therefore, white LEDs severely lack richness when creating greens and reds. Also, RGB systems are far more efficient, because they can be combined to produce levels of white light that nearly match the levels of red, green, and blue the LEDs need in order to create the current image. With such a close match, less light needs to be filtered out, and less energy is wasted.

Although white LED backlighting is inferior, it is also less expensive, and therefore more commonplace. On the other hand, RGB LED backlighting is often reserved for small monitors and professional color proofing displays on high end printers.

kangaBurg

I’m a little confused. Do the LED backlighting components emit white light? I thought they would give off just red, green, and blue (RGB), which seems to be the standard three colors used by LCD monitors and TVs to create all the colors we see. If they emit white light, that means there are a lot of colors to filter out, so that would be really inefficient.

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    • An LED backlight LCD TV.
      An LED backlight LCD TV.