“Whether, in passing on the validity of a design patent issued on an application filed as a division of an earlier filed application for a utility patent and claiming the benefit of the filing date thereof, we will follow Campbell or overrule it.”
“Our decision is to overrule it, and this should ‘materially advance the ultimate determination of the litigation,’ as the trial judge desired and as 28 U.S.C. ยง 1292(b) contemplates.”