## Facts

- A patent owner and exclusive licensee held U.S. Patent No. 4,108,260 covering an assembly of border pieces used to mount fabric wall coverings, including “linear border pieces” and “right angle corner border pieces” forming a frame.
- During prosecution, the examiner rejected broader claims over prior art framing systems; many claims were cancelled and the issued independent claim emerged from narrowed, rewritten claims.
- The specification largely depicted preformed right-angle corner pieces as distinct components, but also briefly mentioned “improvised corner pieces” made by mitering linear pieces and joining them at right angles.
- The accused wall-frame assemblies used only mitered linear pieces joined at corners, not separate preformed corner pieces.
- The district court construed “right angle corner border pieces” to require preformed corner pieces and entered final judgment of noninfringement.
- The patentees appealed, challenging claim construction and the resulting noninfringement determination.

## Issues

1. Whether “right angle corner border pieces,” properly construed in light of the specification and prosecution history, includes corners formed by mitering and joining linear pieces.
2. Whether the accused assemblies literally infringe claim 1 when they use only mitered linear pieces at corners.
3. Whether infringement exists under the doctrine of equivalents, or whether prosecution history limits prevent extending the claim to cover mitered-corner assemblies.

## Decision

- The Federal Circuit affirmed the judgment of noninfringement.
- The court construed “right angle corner border pieces” to mean separate, preformed right-angle corner units distinct from linear border pieces.
- Under that construction, the accused products did not literally infringe because they lacked the claimed corner-piece element.
- The court also rejected infringement under the doctrine of equivalents, concluding that the asserted equivalence would improperly expand the narrowed claim scope reflected in the prosecution history.

## Legal Principles

- Claim construction is a legal question centered on the claim language, informed by the specification and prosecution history.
- Where claims distinguish between separate components, infringement requires the accused product to contain each claimed element (or its permissible equivalent), not merely a combined or substituted structure.
- Isolated specification references to alternative embodiments do not broaden otherwise clear structural claim language.
- When claim scope is narrowed during prosecution to secure allowance, the patentee cannot use the doctrine of equivalents to recapture surrendered subject matter.

## Conclusion

Because claim 1 required separate preformed “right angle corner border pieces,” and the accused assemblies used only mitered linear pieces at the corners, the Federal Circuit held there was no literal infringement and no infringement under the doctrine of equivalents, and it affirmed the judgment for the accused infringer.


Unique Concepts, Inc. v. Brown, 939 F.2d 1558 (Fed. Cir. 1991)