Unlike with conventional LCD panels that use cold cathode fluorescent lamp (CCFL) backlights which have a constant light source, local dimming LED backlighting allows the backlight to be turned off in dark image areas, resulting in a "true black".
Samsung unofficially took the wraps off a 40-inch LCD HDTV featuring 500 cd/m2 of brightness, 180-degree viewing angle and a 1366 x 768 pixel (720p) HD resolution. The widescreen panel also claims to offer an impressive 100,000:1 contrast ratio, achieved using with local dimming. The hardware company also showed off a 2560x1600 (WQXGA) resolution 30-inch LED-backlit model featuring 16.7M colors, 300cd/m2 brightness, 6ms response, 180-degee viewing angle and a 900:1 contrast ratio. A 15.4-inch 1440x900 resolution LED-backlit LCD which offers 330cd/m2 brightness, 262k colors and a covers 45% of NTSC color gamut, is only 5.8-mm thick and has a 3.1W power consumption, making it perfect for notebooks.