How does the accessibility of foreign patents affect their use as prior art?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The accessibility of foreign patents is crucial in determining their use as prior art. Even if a foreign patent is difficult to access, it may still be considered prior art if it’s publicly available. The MPEP 2126 cites the case of In re Carlson, which states:

“We recognize that Geschmacksmuster on display for public view in remote cities in a far-away land may create a burden of discovery for one without the time, desire, or resources to journey there in person or by agent to observe that which was registered under German law. Such a burden, however, is by law imposed upon the hypothetical person of ordinary skill in the art who is charged with knowledge of all contents of the relevant prior art.”

This means that even if a foreign patent is difficult to access due to geographical or linguistic barriers, it can still be considered prior art if it’s technically available to the public.