OLED screen

An OLED screen does not have a full-screen backlight like LCD screens, instead displaying images using light emitted by each individual pixel. One strength of OLED screen is that deep blacks can be represented by turning a pixel's light off.

On the other hand, the same image being continually (or repeatedly) displayed over a long period of time can lead to "burn-in", a phenomenon where a faint remnant of the image remains visible.
Also, changing the screen brightness can show slight colour differences.
This does not indicate a breakdown or failure, and is instead due to the general intrinsic properties of OLED screen.

Note: When using your Nintendo Switch – OLED Model , please adhere to the following to enjoy your games and their vivid images for longer.

• Avoid continuously (or repeatedly) displaying screens without movement or other changes for long periods of time.
  Avoid continuously displaying paused screens or other in-game screens without movement for long periods of time. Similarly, please also avoid this with the HOME Menu, the "System Settings" screen, etc.
• Set a shorter amount of time before your console enters Sleep Mode.
  You can carry out these settings via "System Settings" → "Sleep Mode" on the HOME Menu.
• Avoid excessive screen brightness (don't turn your screen brightness up too high).
  You can adjust your console's screen brightness via "System Settings" → "Screen Brightness" on the HOME Menu.