A more thorough explanation:

Definition: All substantial rights refer to every valuable right in a patent that is transferred when the patent rights or an undivided interest in a patent is transferred. However, a transfer is not considered a transfer of all substantial rights if it is territorially restricted, has a shorter term than the patent term, contains field-of-use limitations, or does not convey rights to all claims in the patent.

Example: If a company sells a patent to another company, the new owner will have all substantial rights to the patent. This means they will have the right to make, use, and sell the invention covered by the patent. However, if the original owner only sells the rights to make and use the invention in a specific country, the transfer is not considered a transfer of all substantial rights.

Explanation: The example illustrates that a transfer of a patent may not always include all substantial rights. In this case, the transfer is territorially restricted, which means the new owner does not have the right to make and use the invention in other countries. This limitation makes the transfer incomplete and not a transfer of all substantial rights.