New uniformity photos have been updated. Uniformity issues are clearly visible on the 200 nits CNN TV in red and magenta slides (but not in normal content). This is unusual, as we would expect the maximum brightness CNN TV to show uniformity issues before the 200 nits CNN TV. The 18% 25% window we used in January to measure the color gamut is also becoming more visible on this TV (and the FIFA 18 TV) as the weeks progress, even though we haven't displayed that 18% 25% test pattern since January. We have contacted LG to understand why this is happening and will update this article as we obtain more information.
We contacted LG regarding the strange results in week 4. LG engineers visited our lab a few days ago and were able to confirm the 25% window on the Live CNN and FIFA 18 TVs are a result of a factory issue (see our video here). OLED TVs are produced in a hot process, and after cooling a 25% window is shown on each panel. Some TVs which haven't cooled completely can produce invalid results for the lookup table used by the 'Pixel Refresh' function, causing this 25% window to become visible. Only some 55" OLED TVs were affected during part of 2017.
As this is not an issue with the panel itself, it is possible to apply a fix to the lookup table. LG will apply this fix to anyone who presents this issue to their support, for free, even after the warranty period has long expired. They have fixed our two affected TVs (see the uniformity photos below). Note that this doesn't fix other uniformity issues as the result of static content, only the 25% window caused by a factory defect. LG has also confirmed that there is variation between panels, which is why some OLED appear more prone to developing uniformity issues (as in the case with our Live CNN (200 nits) vs Live CNN (Max).)
