LED-backlit LCD
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LED-backlit LCD is a type of liquid-crystal display (LCD) that uses LED lights for its backlight instead of older cold cathode fluorescent (CCFL) backlighting.[1] LED-backlit displays are similar to CCFL-backlit LCDs in technology, but have several advantages.
Some LED-backlit televisions are called LED TVs, though they are not true LED displays.[1][2]
Limitations
[change | change source]LED-backlit LCDs cannot produce true black colors as well as OLED or microLED displays can. Even in dark areas, a small amount of light may come through. Some LED-backlit LCDs use "local dimming," which darkens certain parts of the screen to improve contrast, though this may create a "halo" effect around bright parts of the display.[3]
Comparison with CCFL-backlit LCDs
[change | change source]Compared to CCFL backlighting, LED backlighting offers:
- More colors (with certain LED types)[4][5]
- Greater contrast ratio
- Slimmer, with some screens less than 0.5 inches (13 mm) thick
- Lighter and cooler, sometimes half the weight of a CCFL display
- 20–30% less power use and longer lifespan
- Greater reliability[6]
LED arrangements
[change | change source]LED backlights use either edge-lit or direct-lit LEDs:[7]
- Edge-lit (ELED): LEDs are around the edges of the screen, often with frame dimming or basic local dimming.
- Direct-lit (DLED) or Full Array: LEDs are directly behind the screen. Some models support local dimming for better contrast.
Technology
[change | change source]LED-backlit LCDs do not light up by themselves; they need backlighting. Different ways to use LEDs include white LEDs and RGB (Red, Green, and Blue) LEDs. RGB LEDs can show more colors than white LEDs. The first full-array LED-backlit TV was the Sony Qualia 005, released in 2004, using RGB LEDs.[8][9][10]
Many "LED TVs" are LCDs with LEDs controlled to match video details (dynamic backlight control or local dimming).[11][12]
Energy standards for TVs now require lower power use, pushing companies to make more energy-efficient screens.
Energy efficiency and environment
[change | change source]LED-backlit LCDs generally use less power than older plasma displays or CRTs, and they are more energy-efficient than CCFL-backlit displays.[13] They also contain fewer toxic materials, like mercury, which is present in CCFLs, making LED displays safer for disposal and better for the environment.[14]
References
[change | change source]- ↑ 1.0 1.1 "LED vs LCD TV Comparison". Archived from the original on 20 May 2017. Retrieved 13 November 2024.
- ↑ "Samsung Electronics (UK) Ltd". asa.org.uk.
- ↑ Shafer, Rob (2022-06-11). "What Is FALD Blooming Or Halo Effect?". DisplayNinja. Retrieved 13 November 2024.
- ↑ Dell Studio XPS 16: Highest Color Gamut Ever?. Anandtech.com, 26 February 2009
- ↑ Competing display technologies for the best image performance; A.J.S.M. de Vaan; Journal of the society of information displays, Volume 15, Issue 9 September 2007 Pages 657–666; http://onlinelibrary.wiley.com/doi/10.1889/1.2785199/abstract?
- ↑ "Plasma Vs LCD vs LED TV". Archived from the original on 10 July 2012. Retrieved 13 November 2024.
- ↑ "Local Dimming on TVs: Direct-Lit, Full-Array, and Edge-Lit". RTINGS.com. Retrieved 13 November 2024.
- ↑ "ソニー、LEDバックライト搭載の液晶テレビ「QUALIA 005」". av.watch.impress.co.jp.
- ↑ "Sony's Qualia Product Line - Nymag". New York Magazine. 13 October 2004.
- ↑ "Lumileds, Sony Develop Groundbreaking LED Backlight Technology". phys.org.
- ↑ "LED local dimming explained". CNET.
- ↑ Chen, Haiwei (24 January 2017). "Pixel-by-pixel local dimming for high-dynamic-range liquid crystal displays". Optics Express. 25: 1973–1984. doi:10.1364/oe.25.001973.
- ↑ "Difference Between LED and LCD". Electronics Hub. Retrieved 13 November 2024.
- ↑ "Cold Cathode Definition". PCMAG. Retrieved 13 November 2024.