didn't find a way to edit.
i want to add that the reason i ask it in this forum is that i read in some places that the reason for it can be something to do with gpu.
i'm also add some info .
after few minutes of grey back light screen it start blinking several times and then turn to black without back light.
This sounds like a monitor issue. Once the system is in the sleep mode, the behaviour of the monitor is not controlled by the display driver.
i read a bit about that.
lots of people have this issue.
some say it's windows power control subject , some gpu driver settings.
if it's monitor issue so why at the end it do turn to black( without back light) but it takes more time ,compare to what i remember it was, until it doe's