Hi @eskybob
Do you want to know how long your display is active?
You can see that under Settings » Battery!
If you want to view that info on your display (like a widget), i believe it´s not possible. Probably with an app available at Play Store. However, i can recomend you about a Battery shortcut directley in your screen. It could be useful! Just long press "Settings" and pin the "Battery" badge! 
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