localdimming

Local dimming is a display technology designed to improve contrast ratios and picture quality, particularly in displays that use an LED backlight. Instead of a single backlight illuminating the entire screen uniformly, local dimming divides the backlight into multiple zones. Each zone can be dimmed or brightened independently.

This zoning allows for greater control over the light output. When displaying dark scenes, the zones corresponding to those areas can be dimmed significantly, or even turned off completely, creating deeper blacks and reducing light bleed. Conversely, bright areas in the scene can be illuminated more intensely. The result is a higher perceived contrast ratio, meaning the difference between the darkest blacks and the brightest whites is more pronounced.

The effectiveness of local dimming is dependent on the number of zones and how they are managed. Displays with more zones generally offer better picture quality, as they can more precisely match the backlight to the content on screen. However, too few zones can lead to visible artifacts, such as haloing around bright objects on a dark background, or a "blooming" effect where light bleeds into adjacent dark areas. The algorithms used to control the dimming zones also play a crucial role in minimizing these undesirable effects and optimizing the overall image.