What is necessary for an assignment of patent rights to be legally binding?

For an assignment of patent rights to be legally binding, it must be in writing. This requirement is established by Section 261 of the Patent Act, which states that assignments of patents must be recorded in writing to be effective against subsequent purchasers, mortgagees, or other transferees. A written assignment provides clear evidence of the transfer of rights and the parties involved, thereby reducing potential disputes over ownership.

Verbal agreements are generally not sufficient to convey patent rights, as they lack the necessary documentation to provide proof of the transaction. While having a notary public witness the signing of an agreement can add a layer of verification, it is not a requirement as long as the assignment is documented in writing. Lastly, an assignment does not need to be made exclusively by a registered patent attorney; inventors or other entities can also execute such assignments as long as they comply with the written requirement. Thus, the correctness of the answer lies in the clear legal framework mandating written assignments for patent rights.