Introduction
Local dimming is a display technology used in modern televisions, monitors and projectors that enhance the dynamic contrast of images. Dynamic contrast is the difference between the darkest and brightest parts of an image. This technology is used to improve the rendering of black levels and provide a better viewing experience to users. In this article, we will explore local dimming technology in depth and how it enhances dynamic contrast.
What is Local Dimming Technology?
Local dimming technology is a backlighting technique used in modern displays that turns off or dims the backlight in certain areas of the screen to produce deeper blacks in contrast to brighter areas of the image. The technology uses a series of dimming zones placed behind the screen and can be divided into two categories: global dimming and local dimming.
Global Dimming
Global dimming is a basic form of dimming technology that reduces the overall brightness of the entire screen. This method is less effective in rendering images with high dynamic range and can cause unwanted artifacts like haloing, where bright objects appear surrounded by a bright halo.
Local Dimming
Local dimming is a more advanced technique that works by adjusting the brightness levels of individual pixels in accordance with the content displayed on the screen. By dimming certain areas of the screen and turning off the backlight in dark areas, local dimming enables displays to achieve deeper blacks and enhances the contrast of the image.
How Local Dimming Works
Local dimming works by dividing the screen into small areas or zones of varying brightness levels. The dimming zones are then controlled by light sensors that detect the brightness levels of the image displayed on the screen. When a dark image is displayed, the local dimming algorithm turns off the backlight in corresponding zones to produce deeper blacks, while the bright areas of the screen remain unaffected.
Types of Local Dimming
There are three types of local dimming techniques:
Edge-Lit Local Dimming
Edge-lit local dimming is the most basic local dimming technique used in televisions and monitors. This method uses a handful of LEDs positioned along the edges of the screen to provide backlighting. Edge-lit local dimming is less effective in creating deep blacks, and can produce unwanted artifacts and backlight bleeding.
Direct-lit Local Dimming
Direct-lit local dimming technology uses a grid of LED lights placed behind the screen to produce backlighting. This method is effective in providing a higher number of dimming zones and producing deeper blacks, but is more expensive than edge-lit dimming.
Full-Array Local Dimming
Full-array local dimming is the most advanced type of local dimming technology. It uses an array of LEDs placed behind the screen in a matrix, which provides the most precise level of control over the backlighting. Full-array local dimming is the most effective method in enhancing dynamic contrast and producing deep blacks without unwanted artifacts.
Benefits of Local Dimming
The benefits of local dimming technology are numerous. Firstly, local dimming enhances dynamic contrast, producing deeper blacks and brighter whites, which improves the overall quality of the image. Secondly, it prevents haloing and other unwanted artifacts, producing a clear and sharp image. Thirdly, local dimming technology reduces power consumption by turning off the backlight in areas where it is not needed, which saves energy and prolongs the lifespan of the display.
Local Dimming versus OLED
Local dimming technology is often compared to Organic Light Emitting Diode (OLED) displays, which do not require backlighting to produce images. While OLEDs can achieve deeper blacks than local dimming displays, they come with their own set of disadvantages. For instance, OLEDs are more expensive, and their lifespan is shorter than local dimming displays.
Conclusion
Local dimming technology is an essential feature in modern displays that enhances dynamic contrast, producing deeper blacks and brighter whites. The technology is divided into global and local dimming, with local dimming being the more advanced technique. Local dimming works by adjusting the brightness levels of individual pixels in accordance with the content displayed on the screen. There are three types of local dimming techniques: edge-lit, direct-lit, and full-array. The benefits of local dimming technology include better image quality, reduced power consumption and an extended lifespan of the display.