## Facts

- Laitram owned U.S. Patent No. 3,952,311, directed to high-speed electro-optical printing systems using an array of radiation emitters and photosensitive recording material moving at a substantially constant speed.
- NEC sold high-speed printers that Laitram alleged infringed claims 1 (apparatus) and 2 (method) of the patent.
- During infringement litigation, a third party sought PTO reexamination; the PTO initially rejected claims 1 and 2 over prior art.
- Laitram amended claims 1 and 2 in reexamination, including adding an express “type quality” limitation (printing type-quality alphanumeric characters) and further limitations tied to speed, movement direction, and coordination between material motion and emitter activation.
- The PTO allowed the amended claims and issued a reexamination certificate.
- The timing of infringement mattered because damages for substantively changed reexamined claims are limited to post-certificate conduct.

## Issues

1. Whether amendments to claims 1 and 2 during reexamination substantively changed claim scope such that, under 35 U.S.C. § 307(b), damages were limited to acts occurring after the reexamination certificate.

## Decision

- The Federal Circuit reversed the district court’s denial of NEC’s motion for judgment as a matter of law.
- The court held that the reexamination amendments to claims 1 and 2 substantively narrowed the claims and therefore were not “identical” in scope to the original claims under § 307(b).
- Laitram could not recover damages for infringement occurring before issuance of the reexamination certificate.

## Legal Principles

- Under 35 U.S.C. § 307(b) (incorporating the effect of 35 U.S.C. § 252), pre-certificate damages are available only if the reexamined claim is “identical” in scope to the original claim.
- “Identical” does not require verbatim language; it requires no substantive change in claim scope.
- Courts determine substantive change by comparing the scope of the original and reexamined claim language, not by asking whether the amendment was consistent with the specification or with the patentee’s intent.
- Adding an express limitation (including one supported by the specification but absent from the original claim) is substantive if it excludes subject matter previously within the claim’s literal scope.
- Amendments that “clarify” but also narrow coverage are treated as substantive changes that cut off pre-reexamination damages.

## Conclusion

The Federal Circuit held that adding express “type quality” and related coordination/speed limitations during reexamination narrowed the claims, making them non-identical to the originals and barring recovery for infringement predating the reexamination certificate.


Laitram Corp. v. NEC Corp., 163 F.3d 1342 (Fed. Cir. 1998)