Abstraction, Filtration, and Comparison in Patent Law

Abstract

This essay explores how copyright's doctrine of abstraction, filtration, and comparison is being used in patent law, and how that use could be improved. This test, which finds its roots in the 1930's but wasn't fully developed until the 1990's, is one that defines scope for determining infringement. The copyrighted work is abstracted into parts, from ideas at the highest level to literal expression at the lowest. Then, unprotected elements are filtered out. Finally what remains of the original work is compared to the accused work to determine if the copying was illicit.

This sounds far removed from patent law, but there is a kinship, though perhaps one that is not so historic and a bit hidden. The essence of the test is determining protectable subject matter. These same needs permeate patent law as well. This essay explores how the test is implicitly used and should be explicitly used.

With design patents, the test might apply as it does in copyright, with functional elements being filtered out during infringement. Current precedent allows for this filtering, but not clearly or consistently. With utility patents, the abstraction, filtration, and comparison happen earlier, during the test for patentable subject matter. Here, the comparison is with what is conventional or well known. The essay concludes by discussing why the application is different for design and utility patents.

Keywords: Abstraction, Filtration, Comparison, Patent, Copyright, Infringement