The original patent contains no such notice, so its contents are in the public domain. Note: This only applies to images published before March 1, 1989. Patents published after that date are most likely copyrighted, unless in the public domain for another reason, such as {{PD-ineligible}}.

U.S. Patent 2,626,990

Date/Time	Dimensions	User	Comment
2013-04-22 17:08	939×572× (229683 bytes)	Spinningspark	{{Information |Description=Cross-coupled filter in waveguide, described by the inventor as "paralleled resonator transducers". |Source=US patent US2626990 |Date=4th May 1948 (filed) |Author=[[John R. Pierce]] |other_versions= }} == Licensing == {{PD-U...