TFT Vs. LED Display

by Dan Stone

"Thin film transistor" and "light emitting diode" are two terms used to describe different parts of a liquid crystal display screen. It is possible for a LCD to use both TFT and LED technology at the same time. TFT technology handles how the pixels are displayed on the screen whereas LED refers to how the screen lights up. Most consumer LCD displays use TFT technology; however, some higher-end screens use Organic Light-Emitting Diode technology instead. LED are an improvement over fluorescent back-lighting technology.

Thin Film Transistor Displays

TFTs are a type of active matrix display that controls individual pixel updates several times per second on the screen to update the image relative to the content source. These displays are built from a thin layer of transistors located on the back of the screen that handles screen animation. The display receives information from a computer or video source and updates the screen contents row-by-row so many times per second that it looks like the entire screen is updating content in real-time as opposed to being a collection of frames. A more advanced type of TFT technology called In-Plane-Switching improves the screen viewing angles.

Organic Light-Emitting Diode Displays

Unless a LCD screen is called a Organic Light-Emitting Diode Display, it uses TFT technology. OLEDs improve upon TFT technology by illuminating the screen itself and making a backlight unnecessary to view screen content. OLEDs feature a more vibrant picture, a wider viewing radius, thinner screen, faster refresh rate and less power consumption than LCDs. OLED technology beats TFT technology for display quality, but is more expensive and requires a glass-covered screen.

Light Emitting Diode Backlights

A display that carries the LED tag in its name is still a LCD screen; the LED name is used because it's shorter than the more descriptive names like LED-LCD or LED-backlit-LCD. LEDs are used as a static, one-color light source in power indicators and flashlights. LED screens use a non-colored LED light source to illuminate the screen; this provides a more dynamic brightness range than traditional fluorescent backlighting. LED screens are able to make black appear darker and the brightest colors appear brighter.

Fluorescent Lamp Backlight

If a LCD screen doesn't use LED backlighting or OLED technology, it uses a fluorescent lamp to illuminate screen content. Fluorescent lights aren't as dynamic in brightness range as LEDs, but they are cheaper to manufacture and can still display a high-quality image. In addition to having inferior picture quality, fluorescent lights have a shorter lifespan, take up more space and use more power to operate than LED lights. TVs and monitors that use fluorescent back-lights are actually using the same technology that's used to create fluorescent room lighting.

About the Author

Dan Stone started writing professionally in 2006, specializing in education, technology and music. He is a web developer for a communications company and previously worked in television. Stone received a Bachelor of Arts in journalism and a Master of Arts in communication studies from Northern Illinois University.

Photo Credits

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