If you wish to protect your brand's identity, then you should obtain a trademark. Trademarks protect brand names, logos, and slogans by preventing others from using confusingly similar elements to misguide consumers.
If you wish to protect a new invention or the technical aspects of your product, such as its underlying functionality or mechanism, then you should obtain a patent.
Bluetooth is a useful illustration of the distinction. The patents protecting Bluetooth cover the technical inventions (e.g., "Frequency hopping piconets in an uncoordinated wireless multi-user system," patent no. 6590928). The name "Bluetooth" itself is protected by a trademark. The two instruments protect entirely different things.
You can learn more about the differences between IP protection mechanisms in this article.