What conditions must be met for a later buyer to have good title of a patent?

For a later buyer to obtain good title to a patent, it is crucial that the first buyer did not record the assignment and that the later buyer was unaware of the first sale. This situation arises because the U.S. patent system operates under a "first to invent" rule and a "first to file" principle. When the first buyer fails to record their assignment, the patent remains technically open to subsequent transactions, allowing a subsequent buyer who is unaware of the previous transaction to secure good title.

Recording an assignment is important because it provides public notice of ownership and protects the rights of the assignee. If the original buyer does not record the assignment and the later buyer is completely unaware of the existence of that first transaction, the later buyer can obtain good title to the patent. This aligns with the principles of good faith and reliance in property transactions.

In contrast, the other options propose conditions that either impose unnecessary requirements on the second buyer or misinterpret the importance of recording assignments in relation to ownership transfer. Understanding the nuances of patent assignment and the recording system is essential for navigating such transactions effectively.