Terminal disclaimer, in patent law lingo, means a statement that disclaims some of a patent’s duration. The disclaimer has the effect of making the patent coterminous, time-wise, with an earlier patent — one that covers substantially the same invention. It serves to avoid the sin of double-patenting the invention.
Got that? Great.
One other thing. Blawgletter learned yesterday that a terminal disclaimer "simply is not an admission that a later-filed invention is obvious." Motionless Keyboard Co. v. Microsoft Corp. , No. 05-1497 (Fed. Cir. May 29, 2007). We suppose that one could assume, as the district court in Motionless Keyboard did, that a patent holder wouldn’t file a terminal disclaimer unless its later patent duplicated the earlier one, making it obvious. But we can also see why the Federal Circuit wouldn’t want to make admission of obviousness the price of filing a terminal disclaimer. That would encourage unnecessary disputes about double-patenting.