O.k then this is definitely not a normal function no matter what .
At first i was thinking of some sort of screen saver perhaps but this is not the case .
I`m afraid that this tv will need to be serviced , something beyond adjustment is at play here .
Did you buy this tv locally at a place like curry`s or online perhaps ?
If locally then i would contact that store to see if they have their own service center or contact samsung at this number 0330 SAMSUNG (7267864) and they should be able to tell you where is the samsung ASC (authorized service center ) near you.
Just have your paperwork (serial number, date of purchase etc.) handy when you call them
You can also look at their webpage at the link below;
Wish i had an easier solution for you today like some sort of reset but not the case i`m afraid.
Hope this still help somewhat and please take the time to rate my answer positively (use the smiley) if that answers your question as it is the only way i get paid for helping you , otherwise do not rate at all , just let me know and we`ll see what can be done.
Note that you can reach me here at any time after rating if you have questions.
Thank you and good luck with your warranty claim