By Audrey Millemann

In Tokyo Keiso Company, v. SMC Corporation, 2009 WL 59769 (Fed. Cir. 2009)the Federal Circuit has again relied on the Supreme Court’s decision in KSR in invalidating a patent for obviousness.

The plaintiff, Tokyo Keiso, is the owner of a patent that covers a volume flow meter that measures the volume of a fluid flowing through a pipe or measuring line. The patent describes the prior art devices as having two measuring heads, one on each end of the measuring line, and using an acoustic signal transmitted through the metal measuring line. The problem with the prior art devices was that the sound travelled faster through the metal than through the fluid, resulting in inaccurate measurements. The invention in Tokyo Keiso’s patent used a measuring line made of plastic, instead of metal, which caused the acoustic signal to travel more slowly through the plastic than the fluid and made the flow meter more accurate. 

Tokyo Keiso sued SMC Corporation for patent infringement in the Central District of California in 2006.  In 2007, SMC moved for summary judgment of invalidity based on obviousness. SMC’s motion was based on two prior art references – a patent and an article – that both disclosed flow meters with plastic tubing.

The district court granted SMC’s motion.  The court found that the prior art references rendered the patent obvious and that, because neither reference had been before the PTO during patent prosecution, the patent’s presumed validity was weakened. 


Tokyo Keiso appealed the decision to the Federal Circuit.  In affirming this district court’s decision, the appellate court quoted from the Supreme Court’s decision in KSR v. Teleflex, 127 S.Ct. 1727, 1745-46 (2007): “The ultimate judgment of obviousness is a legal determination.  Where … the content of the prior art, the scope of the patent claim, and the level of ordinary skill in the art are not in material dispute, and the obviousness of the claim is apparent in light of these factors, summary judgment is appropriate.”  Tokyo Keiso Company, supra, at *3. 


Tokyo Keiso asserted that the district court did not perform a claim-by-claim analysis.  Tokyo Keiso also argued that there were disputed questions of fact, including that the prior art references did not address the specific problem solved by the patented invention and that a person having ordinary skill in the art would not have utilized the prior art references to solve the problem.  Tokyo Keiso also contended that the prior art references did not teach all of the limitations of the patent, that the patent was entitled to a presumption of validity, that the references were cumulative, and that the district court did not give any weight to the secondary considerations of nonobviousness (long-felt need and commercial success).  SMC disagreed with each of Tokyo Keiso’s points and asserted that the district court had properly followed KSR.


The Federal Circuit affirmed the district court’s grant of summary judgment.  The court held that the patent was obvious based on the prior art article combined with the admissions in the patent’s specification that certain limitations were present in the prior art.  According to the court:

“Valid prior art may be created by the admissions of the parties…[A] statement by an applicant during prosecution identifying certain matter not the work of the inventor as ‘prior art’ is an admission that the matter is prior art.”


Id. at *5, quoting Riverwood International Corp. v. R.A. Jones & Co., 324 F.3d 1346, 1354 (Fed. Cir. 2003).  The court found that Tokyo Keiso had admitted that the only difference between its invention and the prior art was the material that the measuring line was made of (plastic).  The court concluded that the prior art article relied upon by SMC disclosed the use of plastic.


The court further found that a person having ordinary skill in the art would have combined the prior art article with the prior art admitted in the patent. 

“When a work is available in one field of endeavor, design incentives and another market forces can prompt variations of it, either in the same field or a different one.  If a person of ordinary skill can implement a predictable variation, § 103 likely bars its patentability.”

Id. at *6, quoting KSR, supra, 127 S.Ct. at 1740.


The court also held that there were no disputed material facts because the prior art article clearly disclosed the limitations not present in the admitted prior art.  Id. at *6.  Lastly, the court held that the secondary considerations of nonobviousness asserted by Tokyo Keiso did not overcome the strong evidence of obviousness.  Id. at *7.