Some Lumia phones have this. Go to SETTINGS and see if you find "Glance screen" if so push on if and it all explain itself. If you do not see it your phone can not use is.
I like mine Always On. I see my notifications whenever I look at my phone, but the screen also still uses the proximity sensor so it is dark when in my pocket or when lying face down on a table.
I forward my Lock Screen Notifications to Glance. Currently it tells me:
Day of the week, Date, Time
Alarm status - if there is a pending alarm you see the icon
Charge status - the charging icon lights up when plugged in or using Qi
Current Calendar entry
Battery Status - my Battery App reports there
Missed phone call icon
Message notification
Primary Email account notification
Skype notification
That's a LOT of info just by looking at the phone - no unlocking the phone is required.
At night I have it set to Green so the light emission is very low key. When my Quiet Hours engage at night, you see the Quiet Hours icon and the notifications don't show. No worries, my Inner Circle always breaks through and anyone who calls 2 times in 3 minutes breaks through.