Screen Burn In

With tablets and phones having docks, i have thought about the idea of getting a Nexus 7 dock making my Nexus 7 a night stand alarm clock. If the screen were to stay on, because of Daydream or just having the clock app on. Would that cause the screen to burn in the clock over time? I know AMOLED has a history of burn in but i dont know about LCD's and the other screens. I have also seen phones on store displays that have their screens on almost all the time with images burnt into them. The last thing i would want to do is do this to my tablet all for the sake of knowing what time it is when i roll over in bed wondering how much more time i have to sleep. It's also a nice idea to use as a photo frame of sorts. As i said, i just don't want to risk problems in the future due to these uses. Thanks to anyone with thoughts, experiences, advice and answers.