Mission Impossible? How to Effectively Draft the Background Section of a Patent Specification in Compliance with Both USPTO and EPO Practice
Preparation of the background section of a specification that complies with the requirements of both U.S. Patent and Trademark Office (USPTO) and European Patent Office (EPO) requirements is a classic conundrum for patent drafters seeking to file an application in both jurisdictions via the Patent Cooperation Treaty (PCT) or direct filings. In U.S. patent applications, statements made in the background section can be considered an admission of prior art, regardless of whether the admitted prior art would otherwise qualify under 35 U.S.C. 102 and regardless of any disclaimer made. Additionally, statements made in the background section of an issued U.S. patent can not only be used against expert testimony that describes the prior art differently and during claim construction, but also can have a limiting effect on claim interpretation. As a consequence, discussion of deficiencies in the prior art can be interpreted as a disclaimer of the related features and therefore can severely (and often inadvertently) limit the interpretation of the claims. In contrast, statements made in the background section of EPO applications that discuss deficiencies and technical problems present in the prior art are expected to be included in order to enable the reader to understand the technical contribution to the art made by the invention as claimed. In particular, according to EPO practice, the applicant is expected to discuss the technical problem solved not just in view of the closest prior art at filing (subjective technical problem), but also, more importantly, in view of the prior art cited during prosecution in the context of the problem-and-solution approach (objective technical problem). Accordingly, applicants drafting applications to be filed at the EPO tend to provide a heavy background section with discussions of cited documents, related deficiencies and problem solved and later adjust it in view of the objective technical problem in view of the objective technical problem arising during prosecution. What constitutes best practice in this scenario and how the two practices can be harmonized is controversial.