The best source of information about the LN is here:
https://www.reddit.com/r/Bitcoin/comments/7npeh6/lightning_network_megathread/ A to Z. (Highly recommend to check)
Can I Send Funds From Lightning to a Normal Bitcoin Address? (works in opposite way also)
No, for now. For the first version of the protocol, if you wanted to send a normal bitcoin transaction using your channel, you have to close it, send the funds, then reopen the channel (3 transactions). In future versions, you and your peer would agree to spend out of your lightning channel funds just like a normal bitcoin payment, allowing you to use your lightning wallet like a normal bitcoin wallet.
Anyway you will have to transfer the funds to the wallet which uses LN protocol, and from there you can use your BTC via LN.