The revisions address two main aspects of invalidation proceedings: additional ways to amend patent documents, and clearer rules for supplementing invalidation grounds and evidence.
1. Amendments to Claims
Previously, patentees could delete claims, combine claims or delete technical solutions. The revised Guidelines replace “combining claims” with “further limiting a claim” and add correction of obvious errors. Further limitation means incorporating one or more technical features from other claims of the same patent to narrow the claim’s scope. This gives patentees more options during invalidation proceedings.
Consider the following claims:
Claim 1: A+B.
Claim 2: A+B+C+D.
Claim 3: A+B+E.
Previously, after abandoning claim 1 during invalidation, the patentee could not obtain A+B+C or A+B+D by amendment. Under the revised rules, both amendments can be accepted. The combinations A+B+C+E and A+B+D+E can likewise be accepted by the Patent Reexamination Board.
Further limitation must still comply with the other amendment requirements, including Article 33 of the Patent Law. A patentee cannot combine features arbitrarily to create subject matter extending beyond the original claims and description. Features disclosed only in the description or drawings still cannot be added to the claims during invalidation proceedings.
2. Additional Grounds and Evidence
For procedural fairness, when the patentee further limits claims or corrects obvious errors, the invalidation petitioner may add and explain grounds directed to those amendments within the period specified by the Patent Reexamination Board.
Using the example above, if feature C from original claim 2 is added to claim 1 to produce A+B+C, the petitioner may argue that the amendment adds subject matter or lacks support in the description. It may not, however, newly argue that the wording of feature C is unclear, because that wording was already present and was not introduced by the amendment. Such a ground should have been raised when the invalidation request was filed.
Where the patentee amends the claims, the petitioner generally may not add new evidence more than one month after filing the invalidation request. It may adjust the combinations of existing evidence and supplement common-knowledge documents so that patentability can be evaluated fully. There are three reasons for this approach:
1) Amendments during invalidation cannot introduce technical features absent from the earlier claims, so they do not create unexpected technical solutions.
2) The rules prevent surprise evidence attacks after the patentee has amended the claims.
3) The rules avoid unreasonable delay. If each amendment allowed additional evidence, and each new item of evidence allowed further amendments, the proceedings could continue indefinitely.
Claims therefore play an even more important role. When budget permits, applicants should consider including in dependent claims all technical features that may contribute to the invention and using claim dependencies to provide multiple combinations. This preserves more amendment options in any later invalidation proceedings.
