The screen on your Lumia phone goes on standby to save power when you're not actively using it. The glance screen can still show the time and other content even when your screen times out.
On Start , swipe over to the All apps list, and then select Settings > Extras > Glance screen.
Choose the time the glance screen stays on.
If you've set a background photo as your lock screen, you can set it to appear on your glance screen too. To set a background photo, turn on Background photo. You can also turn on Date, Notification icons, and Detailed app status.
To change the setting for Night mode, select the color for the text on the glance screen, or choose to hide the glance screen completely for a period of time. Then set the time when you want to have night mode on.
Note: Some glance screen settings aren't supported by all Lumia phones.