Method, device and use for determining the start of relaxation after a burn-in process at optical display devices controllable pixel by pixel

The invention relates to a method for determining a start of relaxation (tR) when switching over an optical display device (1) controllable pixel by pixel from a burn-in image (EB′) to a relaxation image (RB), wherein. A trigger image area (TB) having at least one image pixel is set to pixel values such that a parameter determined based on the at least one pixel value across the trigger image area (TB) differs between the burn-in image (EB′) and the relaxation image (RB). The local distribution of a greyscale value is continuously recorded by means of a camera (3, 13). A trigger subfield (20) comprising at least one sensor pixel (15) is defined matching the trigger image area (TB). A trigger parameter (T) is continuously determined from the pixel values of the at least one sensor pixel (15) in the trigger subfield (20) with a trigger clock rate and the start of relaxation (tR) is determined as the point in time at which the continuously determined trigger parameter (T) crosses the trigger threshold value (TS)