Quantum Corp. v. Rodime, PLC
65 F.3d 1577 (1995)
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Rule of Law:
Amending a patent claim during reexamination to enlarge its scope, in violation of 35 U.S.C. § 305, renders the broadened claim invalid. A claim is considered enlarged if it includes within its scope any subject matter that would not have infringed the original patent.
Facts:
- Engineers at Rodime PLC filed a patent application for a 3.5-inch hard-disk drive system.
- The initial application recited a track density of "approximately 600" tracks per inch (tpi).
- Following a rejection by the patent examiner, the applicants amended the claims to recite a track density of "at least 600" tpi.
- The U.S. Patent and Trademark Office (PTO) issued the original '383 patent with the "at least 600 tpi" limitation.
- Rodime, now the owner of the patent, subsequently requested a reexamination of the '383 patent.
- During the reexamination, Rodime amended the claims, changing the track density limitation from "at least 600" tpi to "at least approximately 600" tpi.
- The PTO allowed the amendments and issued the reexamined '383 patent with the new language.
- Quantum Corporation is a manufacturer of disk drives that Rodime alleged were infringing its reexamined patent.
Procedural Posture:
- Quantum Corporation filed a declaratory judgment action against Rodime PLC in the U.S. District Court for the District of Minnesota, seeking a declaration that Rodime's patent is invalid, unenforceable, and not infringed.
- Rodime filed a counterclaim against Quantum for patent infringement.
- Quantum moved for summary judgment, arguing certain claims of the reexamined patent were invalid under 35 U.S.C. § 305 for being impermissibly broadened during reexamination.
- The district court granted Quantum's motion for summary judgment, ruling the claims were invalid.
- The district court entered a final judgment in favor of Quantum.
- Rodime PLC, as the appellant, appealed the district court's judgment to the U.S. Court of Appeals for the Federal Circuit.
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Issue:
Does amending a patent claim's limitation during a reexamination proceeding from "at least 600 tpi" to "at least approximately 600 tpi" impermissibly broaden the scope of the claim in violation of 35 U.S.C. § 305, thereby rendering the amended claim invalid?
Opinions:
Majority - Plager, J.
Yes, amending the claim from "at least 600 tpi" to "at least approximately 600 tpi" impermissibly broadens the claim under 35 U.S.C. § 305, rendering the claim invalid. The court reasoned that claim construction is a question of law. The original limitation, "at least 600 tpi," sets a precise and absolute lower limit of a range (600 and up). The addition of the word "approximately" eliminates that precise lower limit, extending the scope of the claim to cover subject matter not covered by the original patent, specifically track densities reasonably close to but less than 600 tpi. This expansion of scope during reexamination is explicitly prohibited by § 305. The court further held that the proper legal consequence for such a violation is the invalidity of the claim. The court reasoned that it cannot redraft the claim to its original scope, and remanding to the Patent Office would create an improper incentive for patentees to attempt to broaden claims, knowing the only penalty would be a return to the status quo. Therefore, to give effect to the statutory prohibition, an impermissibly broadened claim must be held invalid.
Analysis:
This decision solidifies the legal consequence for violating 35 U.S.C. § 305, establishing that patent claims impermissibly broadened during reexamination are invalid. It serves as a strong deterrent to patent holders, clarifying that reexamination is a tool for narrowing or correcting claims, not for expanding their scope to capture competitor products. The ruling affirms that courts will not use their equitable powers to "fix" improperly broadened claims by rewriting them or remanding to the PTO, as doing so would undermine the statutory prohibition. This case reinforces that an impermissible broadening defense can lead to a finding of invalidity in an infringement suit, a harsh but necessary penalty to enforce the statute's purpose.
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