## Facts

- Four inventors employed by 3M filed two patent applications on the same day with practically identical specifications covering a method of molding alpha alumina abrasive particles and resulting abrasive compositions.
- One application issued first as U.S. Patent No. 5,201,916; the other remained pending with broader (genus) claims.
- The disclosed method used a mold cavity filled with a liquid dispersion that would be converted to alpha alumina; a preferred “wiping” approach removed excess dispersion above the mold surface to improve uniformity and grinding performance.
- The Patent Office rejected all claims in the pending application for obviousness-type double patenting over claims of the earlier-issued ’916 patent, treating the issued patent’s claims as nearly identical species claims.
- The Board affirmed the rejection using the one-way double patenting test (comparing the application’s claims to the patent’s claims).
- The applicants argued that because both applications were filed the same day and issuance order was determined by examination sequence, the Board should have applied the two-way test instead.

## Issues

1. Whether the Board erred by applying the one-way obviousness-type double patenting test rather than the two-way test to a same-day-filed application’s genus claims in view of an earlier-issued patent’s species claims to the same inventors.
2. Whether, under the proper test, the pending application’s claims were unpatentably obvious in view of the issued patent’s claims.

## Decision

- The Federal Circuit affirmed the Board’s decision sustaining the examiner’s rejection of all claims.
- The court held the Board correctly applied the one-way test and was not required to apply the two-way test.
- The court agreed that, under the one-way comparison, the pending genus claims were obvious over the ’916 patent’s claims.

## Legal Principles

- Obviousness-type double patenting prevents an applicant from obtaining claims in a second patent (or application) that are not patentably distinct from claims in a first patent, thereby extending exclusivity through obvious variants.
- The default standard is the one-way test: whether the later claim set is obvious over the earlier patent’s claims.
- The two-way test is exceptional and applies only when the Patent Office is solely responsible for the sequence or delay that creates the double patenting problem; same-day filing alone does not trigger the two-way approach.
- When the applicant’s own claiming or prosecution choices contribute to the issuance order and resulting double patenting posture, the applicant is not entitled to the two-way test.

## Conclusion

The court upheld rejection of the pending application for obviousness-type double patenting, holding that the one-way test governs absent Patent Office-caused delay and that same-day filings with applicant-controlled claim allocation do not warrant the two-way exception.


In re Berg, 140 F.3d 1428 (Fed. Cir. 1998)