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PTO Must Apply Phillips Standard when Construing Expired Patents

In an opinion addressing the standard for claim construction of a patent that expires during reexamination, the US Court of Appeals for the Federal Circuit upheld the Patent Trial and Appeal Board’s (PTAB’s or Board’s) decision finding all challenged claims invalid, but found that the PTAB had used the incorrect standard for its claim construction. In re: CSB-System Int’l, Inc., Case No. 15-1832 (Fed. Cir., Aug. 9, 2016) (Stoll, J).

CSB is the owner of a patent directed to a circuit arrangement for integrating an electronic data processing system with telephone systems connected to an integrated services digital network telephone network. A third party successfully petitioned for ex parte reexamination of the patent. During the resulting reexamination proceeding, the examiner construed several claim terms, applying the broadest reasonable interpretation (BRI) standard for the terms “personal computer” and “LAN server,” and, using these constructions, rejected the challenged claims. The PTAB affirmed. CSB appealed, arguing that the PTAB applied the incorrect standard in construing the claims.

The Federal Circuit agreed with CSB that the PTAB should have applied the Phillips standard rather than the BRI standard because the patent expired during the reexamination. While claims are normally construed under the BRI standard in US Patent and Trademark Office proceedings, because an expired patent can no longer be amended to preserve its validity, its claim terms should be construed under the narrower Phillips standard used in district courts.

The Federal Circuit, however, found that there was no basis for limiting the claims as narrowly as CSB argued. For instance, the Court found there was no support for limiting the claim term “personal computer” to exclude personal computers running software to emulate terminals, nor did the term “LAN server” require embellishment beyond its plain meaning.

Thus, the Federal Circuit concluded that the claim construction applied was correct even under the Phillips standard, and affirmed the PTAB’s rejection of all claims.

© 2020 McDermott Will & EmeryNational Law Review, Volume VI, Number 274


About this Author

Angela Park, Scientific Advisor, Mcdermott Will Law firm
Scientific Advisor

Angela Park* is a scientific advisor in the law firm of McDermott Will & Emery LLP and is based in the Firm’s Washington, D.C., office. 

Angela is experienced in the areas of thermodynamics, fluid mechanics, heat transfer, mechanical design, finite element, manufacturing, mechanism design, design optimization, tissue mechanics and solid mechanics.  She has gained technical experience working as an engineer for a multinational auto manufacturer focused on advanced manufacturing technology 

Angela received her M.S. in...

Paul Devinsky, Intellectual Property Attorney

Paul Devinsky is a partner in the law firm of McDermott Will & Emery LLP and is based in the Firm’s Washington, D.C., office.  He focuses his practice on patent, trademark and copyright litigation and counseling, as well as on trade secret litigation and counseling, and on licensing and transactional matters and post-issuance PTO proceedings such as reissues, reexaminations and interferences.