Can a lack of best mode be used to invalidate a patent claim under current law?

The correct answer reflects the current state of patent law, which establishes that a lack of best mode cannot be used as a basis for invalidating a patent claim. The best mode requirement, as outlined in the Patent Act, mandates that an inventor disclose their preferred method of carrying out the invention in the patent application. However, subsequent court decisions and legislative changes clarified that failure to disclose the best mode does not render a patent invalid or unenforceable.

This principle stems from the fact that the primary purpose of the best mode requirement is to ensure that the public receives sufficient information to practice the invention once the patent expires. A violation concerning the best mode does not affect an inventor’s rights, nor does it compromise the patent if the essential elements of patentability, such as novelty, non-obviousness, and utility, have been met. Under current law, a patent can still be maintained even if the best mode requirement has not been fulfilled, as the enforcement of this requirement has diminished significantly in terms of being a ground for invalidation.

This context helps to differentiate why other options suggesting varying conditions for invalidation are not consistent with the established legal framework regarding the best mode requirement.