Unity of invention

Under European patent practice and case law, lack of unity (of invention) can appear either "a priori", before the prior art was examined, or "a posteriori", after the prior art was examined. An a posteriori lack of unity usually results from a lack of novelty or inventive step of the subject-matter of one independent claim.

Under the Patent Cooperation Treaty (PCT), an international application, which is also called PCT application, "shall relate to one invention only or to a group of inventions so linked as to form a "single general inventive concept".[1] If the requirement of unity of invention is not met, the International Searching Authority (i.e., the patent office in charge of carrying out the international search) "is entitled to request the applicant to pay an additional search fee for each invention beyond the first which is to be searched".[2][3][4]

In reaction to such a request from the International Searching Authority (ISA), the applicant may pay all or some of the requested additional search fees, and the International Searching Authority (ISA) then establishes the international search for all or some of the inventions or groups of inventions, respectively.[2][4] The applicant may also decide not to pay any of the additional search fees, and, in such case, the ISA does not carry out a search for the inventions or groups of inventions for which no search fees have been paid. The international search report (ISR) is then established only for the first claimed invention.[2][4]

If the applicant disagrees with the ISA’s finding of lack of unity of invention, the additional fees may be paid under protest.[2][4] In the protest procedure, the applicant files a reasoned statement explaining why it considers that the requirement of unity of invention has been complied with, or that the number of additional fees required is excessive.[2][5][4] After payment of the additional search fees and, if required, of a protest fee,[6] the protest is examined by a review body. If the review body finds the protest justified, it orders the total or partial reimbursement of the additional search fees, and, if applicable, the protest fee, to the applicant.[2][4] When, for instance, the European Patent Office acts as ISA, the review body in charge of examining the protest consists of three members: "the head of a directorate, normally the head of the directorate by which the invitation to pay additional fees was issued, an examiner with special expertise in unity of invention and, normally, the examiner who issued the invitation."[7]

Although U.S. patent law does not use the term "unity of invention", 35 U.S.C. §121 specifies the conditions under which the patent examiner may issue a "restriction requirement", i.e. requesting a split: "applications that claim more than one distinct invention may be subject to restriction to a single invention, and the applicant may prosecute the remaining invention(s) by filing divisional applications."[8] The applicant would have to pay to filing, examination, issuance and maintenance of each divisional separately.

The US Manual of Patent Examining Procedure discusses four situations where an examiner may issue a "restriction requirement", i.e. a split into one or more divisional applications, because even though the inventions are related (i.e. not independent) they are distinct in one or more of the following four cases:

(1) wherein at least one invention is patentable (novel and nonobvious) over the other (though they may each be unpatentable over the prior art)- i.e. the inventions in question have different inventive steps. Alternatively, "Election of species should not be required between claimed species that are considered clearly unpatentable (obvious) over each other."[9] This approach is similar to those of WIPO and the European Patent Office (EPO).(see PCT and EPO sections above). This approach, however, is not often used by the USPTO, because it requires analysis of an inventive step in each claim, which cannot happen before substantial patent examination.

(2) the inventions as claimed are not connected in at least one of design, operation, or effect (e.g., can be made by, or used in, a materially different process) - i.e. alternative uses/methods.[10] The term "distinct inventions" means here that related concepts (such as apparatus for charging the disclosed battery, an apparatus for getting electric power from the battery, a material to make an electrode for the battery) would be considered "distinct inventions" if they can be used not only in a combination with each other. An example of such restriction requirement is:

The examiner noted that Inventions I and II are related as a method and apparatus for its practice, respectively. The examiner further noted that Invention I and Invention II are distinct, if either:

1. The method (Invention II) as claimed can be practiced by another and materially different apparatus or by hand, or
2. The apparatus (Invention I) as claimed can be used to practice another and materially different method.[11]

(3) if two claimed species are mutually exclusive (i.e. if one claim recites limitations disclosed for a first species but not a second, while a second claim recites limitations disclosed only for the second species and not the first). "The claims must not overlap in scope." [12]

(4) finally, an examiner can present an "undue burden" argument to justify her restriction requirement: there would be a serious search burden as evidenced by separate classification, status, or field of search and/or a serious examination burden as evidenced by non-prior art issues relevant to one invention that are not relevant to the other invention[13] A serious search burden can be evidenced by separate classification, status, or field of search. A serious examination burden can be evidenced by, for example, non-prior art issues relevant to one invention that are not relevant to the other invention.

Similar arguments apply to the analysis of whether combination and subcombination (see MPEP § 806.05 (combination and subcombination) and § 806.05(j) (related products or related processes)) are distinct: The inventions are distinct if it can be shown that a combination as claimed: (A) does not require the particulars of the subcombination as claimed for patentability (to show novelty and non-obviousness), and (B) the subcombination can be shown to have utility either by itself or in another materially different combination.[14]

A restriction requirement can be appealed to a USPTO Division Director, but not to a judge.[15] [16] It is also advised that inventors/applicants do not split their applications themselves, but rather always wait for an examiner to issue a "restriction". Otherwise, the applicant can be accused of double patenting later, and have her patents revoked.[17]

The USPTO's approach to "independent and distinct" inventions is different from the "unity of invention" of the EPO's and WIPO's approach.[18] Whereas the EPO would consider claim as relating to the same invention, if the claims have a common inventive step, the USPTO can find the lack of unity in the same application, because of several fields of use (purposes) of the invention. This difference results in a multi-fold larger number of divisional US patents being issued compared to UK, German or French patents that originate from the same Paris Convention or Patent Cooperation Treaty (PCT) priority application.

The analysis used to determine whether the Office may require restriction differs in national stage applications submitted under 35 U.S.C. 371 (unity of invention analysis) as compared to national applications filed under 35 U.S.C. 111(a) (independent and distinct analysis). This difference was confirmed in 1986 by a US Federal Court, which found that when the USPTO acts as an International Search Authority, the USPTO is required to use the PCT rules rather than US domestic rules.[19]

If the USPTO issues a divisional restriction while serving as International Search Authority (ISA) under the PCT, this restriction would not shield the applicant's US patents from double-patenting accusation later in the national stage of the PCT. Only restrictions issued by the USPTO in a national stage provide immunity from double-patenting.[20]