When do I need to enter my password once I encrypted my phone? I intend to fully encrypt my phone do I need to enter the password at start-up or when unlocking the screen-lock?

If the latter is the case I can't enter my password each time I'd like to unlock my phone of course so is there a way to use a swiping-pattern as password (e.g. 3 times the false one requiring the full password) or sth alike?
When you encrypt your device, It will only ever ask for the decryption key when you boot the device. If correct, it boots normally, and will not ask for that particular password again until next boot. Of course, any screen-lock (normal password) will still be needed to unlock the device when locked.