## Facts

- SRI International owned U.S. Patent No. 3,378,633, covering a spatial filter that permits monochrome recording from which color information can later be derived, and related camera/TV-signal apparatus using the filter.
- The asserted claims were primarily structural, including a filter comprising two angularly superimposed grids of parallel spaced lines of different subtractive primary colors with the same line density (and dependent claims specifying a 45° angle), plus apparatus claims incorporating the filter.
- Matsushita (collectively, MEI) sold a camera and filter accused of infringing several claims, including claim 1.
- In the district court, MEI obtained summary judgment of noninfringement.
- The district court found MEI’s camera/filter structure fell within the literal wording of the asserted claims but concluded noninfringement because MEI’s product allegedly encoded color in a “fundamentally different way.”
- The parties disputed how the accused device operated and how the claim language should apply to the accused structure.

## Issues

1. Whether summary judgment of noninfringement is proper where the accused device meets the literal structural limitations of the claims but the court relies on alleged “fundamental” operational differences to find no infringement.
2. Whether the district court improperly narrowed claim scope by importing unclaimed operational details from the specification’s described embodiment into the claims.
3. Whether genuine disputes of material fact concerning device operation and the application of claim terms precluded summary judgment.

## Decision

- The Federal Circuit reversed the summary judgment of noninfringement and remanded.
- The court held summary judgment was improper because material factual disputes remained regarding the accused device’s operation and the proper application of the claims.
- The court concluded the district court misapplied infringement law by effectively adding operational limitations drawn from the specification’s embodiment that were not recited in the structural claim language.
- The court rejected using perceived differences between the patent’s disclosed embodiment and the accused product as a basis to rewrite claim scope and dispose of infringement as a matter of law.

## Legal Principles

- For structural claims, literal infringement turns on whether the accused device includes the claimed structural elements as written, not whether it operates like a preferred embodiment.
- Courts may not limit claim scope by importing unclaimed operational characteristics from the specification into the claim language.
- Summary judgment is appropriate only when there is no genuine dispute of material fact; disputes over how an accused device works and how technically loaded claim terms apply often require trial resolution.
- Technological differences between an embodiment described in the specification and an accused product do not, by themselves, justify narrowing claims or deciding infringement on summary judgment when the claims are broader than the embodiment.

## Conclusion

The Federal Circuit reversed summary judgment because the asserted claims were structural and the accused device was found to meet their literal terms, while disputed questions about operation and claim application remained; the district court erred by treating “fundamental” operational differences drawn from the specification’s embodiment as dispositive and by resolving fact-dependent infringement issues on summary judgment.


SRI Int’l v. Matsushita Elec. Corp. of Am., 775 F.2d 1107 (Fed. Cir. 1985)