## Facts

- Document Security Systems Inc. (DSS), a New York company, owned European Patent (UK) No. 0 455 750, directed to producing security documents (including banknotes) resistant to replication by scanning-type copiers.
- DSS contended in separate proceedings that euro banknotes infringed the patent; the European Central Bank (ECB) brought a revocation action in England and Wales limited to validity.
- In the Patents Court, the judge revoked the patent solely for added matter, rejecting ECB’s anticipation and obviousness attacks.
- DSS appealed, challenging the added-matter finding.
- ECB filed a contingent cross-appeal, arguing that if the granted claims were derivable from the application as filed, then they should be treated as obvious over the prior art (and also sought to revive anticipation if needed).
- The alleged added matter concerned limitations introduced late in EPO prosecution that framed the invention as overlaying a grid pattern on an image with a pitch slightly different from the scanner pitch so copying yields a moiré-like interference while the original remains visually acceptable.

## Issues

1. Whether the patent as granted contained subject matter extending beyond the content of the application as filed, contrary to Article 123(2) EPC and the Patents Act 1977, by introducing the grid-overlay/pitch-mismatch teaching.
2. If the patent was invalid for added matter, whether it was necessary to decide ECB’s contingent cross-appeal on obviousness (including the “squeeze” argument) or anticipation.

## Decision

- The Court of Appeal dismissed DSS’s appeal and upheld revocation for added matter.
- The court agreed that the added limitations introduced a distinct technical concept not disclosed, even implicitly, in the application as filed.
- Because added matter was dispositive, the court did not decide the ECB’s contingent cross-appeal on obviousness or its challenge regarding anticipation.

## Legal Principles

- An amendment violates Article 123(2) EPC (and corresponding UK invalidity provisions) if it introduces subject matter not derivable by the skilled person, using common general knowledge, directly and unambiguously from the application as filed.
- “Implicit disclosure” cannot be established by reconstructing a specific technical teaching from a general disclosure using the skilled person’s ingenuity after the event.
- In assessing added matter, the court compares the technical teaching of the application as filed (including description, claims, and figures) with the technical teaching of the granted claims; a shift from “integrated-in-image” features to a “separate overlay grid with a selected pitch mismatch” can constitute added matter if not clearly disclosed originally.
- When a patent is invalid on an absolute ground such as added matter, courts may decline to address additional invalidity grounds that become unnecessary to the result.

## Conclusion

The Court of Appeal affirmed revocation because the granted claims’ grid-overlay and pitch-mismatch mechanism was not directly and unambiguously disclosed in the original filing, and the court therefore did not reach contingent arguments on obviousness or anticipation.


Eur. Cent. Bank v. Document Sec. Sys., Inc., [2008] EWCA Civ 192 (Eng.)