Similar question about Bundle Name and Bundle Display Name have been asked, such as:
What's the difference between "bundle display name" and "bund
I just found this document at Apples iOS Dev Library: Making the app name displayed on a device consistent with the name in iTunes Connect. The name is a little misleading, but this solved my understanding about the difference between 'Bundle name' and 'Bundle display name' in an instant.
I hope this will help you guys too. :)