Cases related to the US Patent and Trademark Office usually go to the Patent Trial and Appeals Board (PTAB) and Trademark Trian and Appeals Board (TTAB). Usually, these cases feature a "bench trial" where there is a panel of 3 judges instead of a jury. But are these judges "real" just like the judges of other courts? Yes.
The Supreme Court case United States v. Arthrex, Inc. (2021) found PTAB/TTAB judges are administrative judges as long as the Director has the power for final review.
The main conclusion in Arthrex was that the PTAB (and thus, TTAB) proceedings are constitutional as administrative adjudication since the judges are under the review of the USPTO Director, who is nominated by the President and affirmed by the Senate.
Administrative judges are different than other types of judges as their power comes from the Executive Branch and Appointments Clause instead of Article III. The Supreme Court found that PTAB/TTAB judges are proper as long as there are no tenure protections. The administrative judges must be at the full discretion of the nominated and affirmed officer - the Director of the USPTO. If the Director cannot fire the administrative judges, they would instead need to be affirmed by Congress like other judges.
We have administrative judges to assist with executive branch proceedings so due process is satisfied. If a party is still unhappy with the outcome of an administrative judicial proceeding, they can appeal to another judicial proceeding such as the U.S. Court of Appeals for the Federal Circuit. The judges at CAFC are appointed by the President and affirmed by Congress.
If the President and Congress were involved with patent administrative judge appointments, it would take a very long time since there are so many. It is faster for the President and Congress to delegate that power to the USPTO Director.
While I feel comfortable in calling PTAB and TTAB judges "admin judges," Arthrex was a plurality opinion. This means the judges did not agree on a majority result. This is rare with an odd number of judges, but it does occur. If the Supreme Court ever increases in size, we will see more plurality opinions. I could easily see this decision being challenged in a few years by a party unhappy with a ruling, wanting to vacate it on the grounds the administrative judges did not have the power in the first place. If there are 13 justices on the Supreme Court with mixed interpretations of the Appointments Clause and Stare Decisis Doctrine, this could be quite a mess. Until then, the administrative intellectual property judges are real judges.