L’ASBL, Auto Static Brightness Limiter or in French automatic static brightness limiter is often confused with ABL functionality. On the web, this often creates confusion. The objective of the ASBL is to limit the risk of marking OLED panels by reducing the brightness when static content is detected.
Globally this function is called “Auto Static Brightness Limiter” (ASBL), but the main OLED panel manufacturer, LG, calls it “Temporal Peak Luminance Control” (TPC). Visually it decreases the brightness, which is why it is often mistakenly associated with the term ABL, which often creates confusion on the web.
ASBL: Auto Static Brightness Limiter
This feature detects static content on the screen. If an area of the image remains static, the brightness of the pixels is reduced in order to avoid marking / burning of the screen. During normal use of a television with video, movies or games, the content changes regularly, so the ASBL is very rarely triggered. However, if you pause a video for a short time, you should see the ASBL activate and the image darken.
This is what the TPC (or ASBL) function was designed for, to reduce the risk of tagging with static content. This does not completely eliminate the risk, but it is greatly reduced. In theory, this feature shouldn’t trigger often during normal use.
However, several OLED screen users notice that the ASBL is triggered during dynamic scenes, which in theory should not trigger it. These are often long dark scenes in movies or games. In these cases, the ASBL is too aggressive and poorly analyzes the content and the associated risk, so it unnecessarily reduces the brightness. Then, the initial brightness is restored, which again creates discomfort during viewing.
If you encounter the problem, the good news is that the function can be updated remotely, so hopefully it improves over time.
Can the ASBL be deactivated?
First of all, it is strongly advised not to deactivate the ASBL “Auto Static Brightness Limiter” or “Temporal Peak Luminance Control” (TPC) function. However, you can disable ASBL/TPC and GSR from the service menu on LG TVs, but do so at your own risk.
Is ASBL or TPC a problem for use as a PC monitor?
If you’re using an OLED display with a desktop PC, working with static content can cause this feature to activate quite easily. When this happens, the overall image darkens after a few minutes, and when you switch images, the brightness is restored.
Whether with the LG CX, the LG C1 or the LG 42C2 as a PC monitor, this phenomenon is quite noticeable. Use as a computer screen is undoubtedly the context in which you will see this ASBL / TPC function activate.
On the other hand, OLED desktop monitors like LG UltraFine 32EP950 Pro or Dell Alienware AW3423DW don’t have TPC/ASBL function. The phenomenon is therefore not present. However, we do not yet know how the risk of marking is avoided on these screens.
Finally, it should be noted that when used on a PC screen, the content is still largely static. APL changes, which restore brightness, are limited. However, the ASBL or PTC is content to reduce the brightness of the OLED pixels to try to minimize the risk of burns. The brighter the pixels, the higher the risk of burning. It is also for this reason that we recommend using dark themes with an OLED screen and setting the brightness to a maximum of 120 nits, which is a standard value for this type of use.
Do you have any questions or comments about the ASBL or the TPC? Feel free to use comments.