Patent scope limited by the summary

Normally, the scope of a patent is limited by its claims interpreted in light of the specification. The claims are a series of sentences that describe the invention. In most cases, they are written so that they broadly describe the invention thereby giving the inventor the broadest possible patent and the broadest possible protection.

Sometimes, however, judges ruling on patent cases will rely so heavily on the specification that they artificially limit the scope of the claims. A lawyer whose case is hurt by such an interpretation often presumes that the judge couldn't understand the claims (which can often be confusing) and instead relied on the specification - a much simpler portion of the patent.

This is a case where the judge relied on the summary of the invention to interpret the claims. The summary is a minor portion of a patent that is often informal and only included to make the patent easier to find in the various patent databases.

Whether or not the ruling was legitimate, it is a great reminder the specification should in no way limit the invention or call out necessary or preferred characteristics of an invention.