In our companion article, What is an LED TV? we revealed that LED TVs are actually LCD TVs that use LED edge or backlighting. However, within that category, we also mentioned variations of LCD-based TVs. One of those variations uses Mini-LED technology in combination with LCD technology.
Mini-LED Basics
Mini-LED TVs are LCD TVs that use LED backlighting, but in this case, the LED light bulbs are much smaller than standard-size LEDs used in most LCD TVs.
Tip: The technical term for Mini-LED is Sub-Millimeter Light-Emitting Diode. Officially, if an LED light bulb is .2mm or less in size it can be labeled as a Mini-LED.
Since Mini-LEDs are so much smaller than traditional-sized LEDs used in LCD TVs, up to several thousand can be placed on a backlight panel (depending on the TV’s screen size) instead of just dozens (or less) that may be used on standard LED/LCD TVs.
When fed electric current, Mini-LEDs generate light which is sent through LCD chips (pixels) that contain the image information. The final step is that after the light passes through the LCD chips it also passes through red, green, and blue filters. The resulting images are then displayed.
Mini-LED and Local Dimming
At the manufacturer’s discretion, LEDs or Mini-LEDs can be brightened or dimmed (a process called full-array local dimming) in small groups (dimming zones) according to the image information. This controls how much light is generated for bright and dark areas of the displayed images.
Mini-LED backlighting in combination with the increased number of local dimming zones (several hundred to over a thousand depending on screen size) than is available on a TV with standard LED backlighting adds more precision as more areas of the screen can be dimmed and brightened at the same time. This minimizes unwanted effects such as white halos around bright objects against dark backgrounds and also provides deeper black levels for dark scenes.
Tip: Although the technical limitations of LCD TV technology prevent the display of absolute black, Mini-LED TVs (depending on the exact brand/model) can provide black levels that are deep enough so that some TV buyers that were considering buying an OLED TV (which can display absolute black) might opt for a Mini-LED TV instead.
Mini-LED and Quantum Dots
Some Mini-LED TVs may also include a sheet of Quantum Dots between the backlight and LCD panel layers to further enhance color. For marketing purposes, these TVs might be labeled as Mini-LED QLED TVs.
LG also markets a variation of its Nanocell LCD TVs as “QNED Mini-LED TVs”. These sets include a Mini-LED backlight and a Quantum Dot layer between the backlight and NanoCell layers in combination with an LCD panel to display images.
Tip: Mini-LED backlighting is also used in select PC monitors and other video display devices.