Adele Critchley | September 17, 2015
Dome Patent L.P., vs. Michelle K. Lee, Director, U.S. PTO.
September 3, 2015
Before: Reyna, Schall and Hughes. Opinion by Hughes.
The CAFC affirmed the decision of the District Court of the District of Columbia in U.S. Patent No. 4,306,042 (the ‘042 Patent) in which the District Court held that claim 1 would have been obvious to one of ordinary skill in the art since a single reference that teaches away will not prevent a finding of obviousness, if motivation can be found elsewhere.
The CAFC held that the district court did not err by only requiring the Patent Office to show that claim 1 of the ‘042 patent is obvious by a preponderance of evidence, since in re-examination there is no presumption of validity.
The patent in question, U.S. Patent No. 4,306,042, is owned by Dome Patent L.P., and concerns the polymer science behind making contact-lens materials that are both rigid and oxygen permeable.
Claim 1 recites, in relevant part:
A method of making an oxygen permeable material for the manufacture of contact lens by the synthesization of the monomer 1,1,1-tris(methylsiloxy)methacryloxypropylsilane (a siloxanyl alkyl ester) by the following …
(f) forming an oxygen permeable contact lens material by copolymerizing from 5% to 90% by weight of the 1,1,1-tris(trimethylsiloxy)methacryloxypropylsilane prepared above; 3% to 90% by weight of an ester of acrylic or methacrylic acid; from 0.05% to 90% by weight of a surface wetting agent, from 0.01% to 90% by weight of an oxygen permeable crosslinking agent selected from the class of multifunctional siloxanyl alkyl esters in the presence of a free radical or a photo initiator.
In December 1997, Dome filed suit against six makers of contact lenses for alleged infringement of the ‘042 patent. One defendant requested ex parte re-examination of the ‘042 patent, and as a result the district court stayed litigation pending a final determination in the re-examination proceeding. On re-examination, the U.S. PTO found that method claim 1 was obvious, and thus unpatentable. Dome then filed suit against the U.S. PTO in the U.S. District Court for the District of Columbia. The district court held claim 1 of the ‘042 patent invalid, entering judgment in favor of the U.S. PTO.
The district court concluded that the ‘042 patent would have been obvious to a person of ordinary skill in the art at the time of filing in view of the prior art, including U.S. Patent Nos. 4,120,570 (Gaylord), 4,152,508 (Ellis) and 4,235,985 (Tanaka).
Claim 1 of Dome’s patent covers a method of making Tris and copolymerizing it with an ester of acrylic or methyl methacrylate (MMA), a surface wetting agent, and an oxygen permeable siloxane-based crosslinking agent.
Initially, the CAFC gave a detailed background on the history of contact-lens materials. Briefly, the CAFC asserted that that during the relevant time period, contact-lens makers required materials to be optically clear, sufficiently rigid, oxygen permeable, and hydrophilic. To meet these requirements, contact-lens makers used plastic polymers. In the early 1970’s, it was discovered that silicone could be incorporated into plastics by mixing siloxane-based compounds with MMA, a monomer of polymethyl methacrylate (PMMA). PMMA being the material of the first practical contact lens manufactured. One particular siloxane-compound that was identified as a strong candidate was “Tris,” or 1,1,1-tris(trimethhylsiloxy) methacryloxypropylsilane, due to exception oxygen permeability. However, a significant drawback to this combination, is that Tris is hydrophobic. So to offset this, in the late 1970’s and 80’s polymer scientists looked into combining with other hydrophilic comonmers, crosslinking agents, etc., hoping to strike a balance.
Gaylord discloses a polymer for making rigid, gas permeable contact lenses. Gaylord is one of the first teachings of siloxane-based monomers, including Tris, with MMA, indicating that siloxane-based monomers have become the “industry standard.”
Gaylord teaches combining Tris, MMA, methacrylic acid as a hydrophilic wetting agent, and a hydrophilic cross-linking agent, such as ethylene glycol dimethacrylate. Gaylord does not teach a hydrophobic siloxane-based cross-linking agent.
Ellis teaches a silicone-containing hard contact lens material that, like Gaylord, can include Tris, MMA, methacrylic acid as a hydrophilic wetting agent, and a hydrophilic cross-linking agent, such as ethylene glycol dimethacrylate.
Tanaka teaches a polymer suitable for continuous-wear contact lenses, and it teaches using a variety of cross-linking agents. Like Gaylord and Ellis, Tanaka teaches using a hydrophilic compound, including ethylene glycol dimethacrylate, as a cross-linking agent. Tanaka also teaches that using hydrophobic siloxane-based compounds are preferably employed to enhance oxygen permeability.
Tanaka differs from Gaylord in that rather than using Tris, Tanaka teaches using a different siloxane-based monomer containing both hydrophilic and hydrophobic components. Tanaka teaches this approach is more effective than using Tris-type monomers because simply offsetting the hydrophobic properties of Tris by copolymerizing it with hydrophilic monomers can lead to an opaque product, which is a fatal defect in contact lenses. Tanaka states that “there cannot be obtained a polymer suited for preparing a contact lens which can be comfortably worn continuously for a long period of time” when Tris-type monomers are employed” (Tanaka, column 3, lines 48 to 51).
However, the district court found that, notwithstanding the disclosures in Tanaka concerning Tris-type monomers, motivation to combine the prior art was present, entering judgment in favor of the U.S. PTO.
Accordingly, Dome challenged (i) the standard of review employed; and (ii) the conclusion of obviousness.
(i) The Standard of Review:
Dome alleged that the district court erred by only requiring the Patent Office to show that claim 1 of the ‘042 patent is obvious by a preponderance of evidence, rather than by clear and convincing evidence. According to Dome, the presumption of validity in §282 applies because the action concerns a claim that the Patent Office previously allowed to be patented.
The CAFC disagreed. The CAFC asserted that the clear and convincing evidence standard in the litigation context “stems from our suggestion that the party challenging a patent in court ‘bears the added burden of overcoming the deference that is due to a qualified government agency presumed to have done its job.’ However, in re-examination there is no presumption of validity because when the Patent Office beginnings ex parte re-examination, it reopens prosecution. The CAFC stated that the intent is to ‘start over’ to allow the Patent Office to take a ‘second look’ at patents thought to be doubtful.
Based on this, the CAFC held that the district court did not err by requiring the Patent Office to show by a preponderance of the evidence that the re-examined claim is obvious.
(ii) The Conclusion of Obviousness:
The district court found that a person of ordinary skill in the art understood that high oxygen permeability in contact-lens material was desirable, and this understanding would have motivated said person to combine the Tris monomer disclosed in Gaylord with the Tris-type cross-linking agent disclosed in Tanaka.
Gaylord teaches it would be highly desirable to provide material that has increased oxygen permeability, is wettable, and has improved mechanical properties. Tanaka discloses that contact lenses with poor oxygen permeability would make it impossible to wear them continuously for long periods of time. Therefore, Tanaka preferably employs siloxane-based cross-linking agents, including some that are hydrophobic.
Dome argued that Tanaka teaches away from using Tris, and so motivation to combine is absent. Dome argued that a person of ordinary skill would actually have been inclined to introduce hydrophilic cross-linking agents to Gaylord to offset the hydrophobicity of Tris, but Tanaka warns against this approach. As an alternative, Tanaka suggests other hydrophilic monomers to replace Tris altogether.
The CAFC reminded that “there is no rule that a single reference that teaches away will mandate a finding of non-obviousness,” and that “just because ‘better alternatives’ may exist in the prior art ‘does not mean that an inferior combination is inapt for obviousness purposes.’
The CAFC held that Tanaka does disclose potential disadvantages associated with Tris-type monomers. However, the CAFC held that the other prior art references disclose roadmaps on how to offset the disadvantages to obtain suitable contact lens materials.
The CAFC held that Dome’s own expert testimonies supported the district courts conclusion that motivation to combine was present to one skilled in the art since ‘it is essential that there be an adequate flow of oxygen through the lens,’ that ‘the ability to get oxygen across a contact lens’ was a chief issues, whereas ‘maintaining an nice even tear film, i.e., hydrophilicity, was a secondary problem,’ and that ‘those in the field were turning to siloxane-based compounds to enhance a polymer’s oxygen permeability.’
The CAFC held that while Dome’s argument that the claimed subject matter would not have been obvious in light of Tanaka’s disclosures “is plausible, the burden of overcoming the district court’s factual findings is, as it should be, a heavy one.” The CAFC noted that Dome’s evidence, including evidence of commercial success, was not ‘particularly strong,’ as concluded by the district court.
The CAFC concluded that the claimed subject matter in question would have been obvious to a person of ordinary skill during the relevant time period.
• Keep in mind that there is no rule that a single reference that teaches away will result in a finding of non-obviousness. Motivation can be found in other references that are used to formulate the rejection.
• Be careful what is inferred in the background of the invention section. Motivation to combine prior art refer¬ences could further be supported from the nature of the problem to be solved.
• Consider shifting the problems to be solved by the invention to the summary section, rather than the background of the invention section.