At what time in the patent process is the meaning of a claim term defined?

In 104 Mich. L. Rev. 101 (Oct 2005), Professor Lemley states:

It is a fundamental principle of patent law that the time as of which we determine the meaning of claim terms varies depending on what legal rule is at issue. Where the question is one of novelty or nonobviousness - whether the invention is truly new - the courts compare the patented invention to the prior art as both were understood at the time of the invention. Where the question is one of enablement or written description - whether the inventor understood and described the invention in sufficient detail - courts evaluate the adequacy of the disclosure based on the meaning of the claims at the time the patent application was filed. Where the question involves the meaning of a special patent claim element called a "means-plus-function" claim, courts evaluate the scope of that claim element at the time the patent issues. And where the question involves alleged infringement of the patent, courts evaluate infringement in at least some circumstances based on the meaning of the claim at
the time of infringement. What claim terms would mean to one of
ordinary skill in the art therefore may depend on what legal rule is at issue, and therefore the time as of which we ask the question.



Lemley concludes: The Federal Circuit must choose between the benefits of integrated claim construction and the niceties of time-differentiated claim construction. The only practical approach is to abandon differentiation in the interest of a simple, internally consistent understanding of patent claims.

Hmmm...