Abstract

It’s a simple rule: one patent per invention. This is easy to enforce when patent claims in two patents are identical, but what if the second patent claims something close but not quite the same? For more than 150 years, courts have held that obvious improvements over the prior art cannot be patented. But when inventors seek a small improvement in their own follow-on patents, there may not be any prior art because the law does not typically count inventors’ work against themselves. Inventors can include two similar claims in the same patent without objection, but if they split them into two different patents, they might achieve unfair benefits that come along with having two separate patents on the same basic invention. And so, the “non-statutory” double patenting bar was born. Each invention must be filed in a single patent, and any other patent applications with “patentably indistinct” material are invalid unless the inventor makes concessions about when the double patent will expire and who may own it—concessions that are not required by the Patent Act. But some argue that even with these concessions, double patenting exacts costs on the patent system, especially with respect to pharmaceutical patent thickets.

ISSN

0018-6694

Keywords

Inventor Claims, Double Patents, Patent Act

Disciplines

Intellectual Property Law | Law

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