Availability of continuing applications allows a patent owner to build a portfolio of patents covering multiple aspects of a product, platform, or process, so long as there is support for the claims in the priority patent application. All of the IP5 offices permit some form of continuing application practice, although the content, timing, and procedure for filing such continuing applications differ between the IP5 offices. This article will cover the similarities and differences in the continuing application practice in the IP5 offices.

United States

Under U.S. patent law, a continuing application can be a continuation, divisional, or continuation-in-part (CIP) application filed under the conditions specified in 35 U.S.C. §§ 120, 121, 365(c), or 386(c), and 37 C.F.R. § 1.78. No other IP5 office has a continuation or CIP practice; however, a divisional may essentially be used as a continuation application in some jurisdictions.

A continuing application (continuation, divisional, or CIP) must claim the benefit of the prior-filed application to be entitled to the benefit of the filing date of the prior application. A continuing application must also be filed before the prior application issues or is abandoned. Moreover, a continuing application must name the inventor or at least one joint inventor named in the prior application.

A continuation application allows a patent owner to pursue additional claims to subject matter disclosed in a prior application. No new disclosure can be added to a continuation application. A CIP application, on the other hand, may include new subject matter. Claims in the CIP application may be directed to subject matter disclosed in the prior application, to the newly disclosed subject matter, or both. The priority date of the CIP claims is determined on a claim-by-claim basis, i.e., claims directed to newly disclosed subject matter may only be entitled to the benefit of the filing date of the CIP (and not the filing date of the prior application).

A divisional application can only be filed as a result of a restriction or an election of species requirement (to be discussed in the next IP5 article) made by a U.S. Patent and Trademark Office (USPTO) examiner in the parent application. A divisional application cannot be filed voluntarily. The claims in the divisional application must be directed to an invention that is independent and distinct from that claimed in the prior application.

Japan

A continuing application under the Japan Patent Law is referred to as a divisional application. Any number of divisional applications can be filed based on a parent patent application directed to inventions that are distinctly different from the invention claimed in the parent application. That is, a divisional application may be filed voluntarily, or in response to a determination by the Japan Patent Office (JPO) that the claims in the parent application lack Unity of Invention. If any claim of a divisional application is directed to an invention that is substantially identical to that claimed in the parent application, the claim may be rejected for double patenting under Article 39. A divisional application is entitled to have an effective filing date the same as that of its parent application.

A divisional application may be filed at any time before a first office action is issued; within the time period designated by the JPO examiner to respond to an office action (i.e., whenever an amendment can be filed); within thirty days from receipt of a Decision of Grant; or within four months from receipt of a Decision of Rejection. If the applicant wishes to appeal the Decision of Rejection, the Notice of Appeal must be filed at the same time as the divisional application. Once an appeal is filed, no divisional application can be filed after an allowance or decision of rejection.

A subsequent divisional may be filed based on an earlier divisional, but it is subject to additional limitations.

China

A divisional application may be filed to address a unity defect, or voluntarily to pursue a different set of claims supported by the disclosure of the parent patent application. A divisional application may be filed at any time while a parent application is pending, but no laterthan the expiration of two months from the date of receipt of the Notification to Grant Patent Right for the parent application. If, however, the parent application has been rejected, the divisional application has to be filed (1) within three months of receiving the decision rejecting the parent application; (2) after a request for reexamination of the parent application is filed; (3) within three months of receiving a reexamination decision rejecting the parent application; or (4) during an administrative litigation against a reexamination decision of rejection of the parent application. If the patent application itself is a divisional application, the deadline for filing a divisional application is no later than the expiration of two months from the date of receiving the Notification to Grant Patent Right for the initial parent application. If, however, the examiner issues a unity rejection in a divisional application during examination, the deadline for filing a divisional application is no later than the expiration of two months from the date of receiving the Notification to Grant Patent Right for the divisional application (instead of the initial parent application).

Korea

A divisional application can be filed to pursue additional claims to an invention, or to pursue different aspects of the invention. A divisional application can be filed (1) within the time period for responding to an Office action; (2) within the time period for filing a Request for Reexamination; and (3) within the time period for filing a Notice of Appeal after receiving a final rejection or another final rejection in the reexamination; or (4) within three months of receiving a Notice of Allowance or until the application is registered, whichever is earlier. The divisional application can include any claim that is supported by the specification and the drawings of the parent application.

EPO

A divisional application can be filed at any time from any pending European patent application. The two-year deadline on filing a divisional application, which was introduced in April 2010, was widely unpopular and was lifted effective April 1, 2014. Divisional applications can have claims directed to an invention not claimed in the prior application, or claims directed to the invention previously claimed. A properly filed divisional is entitled to the filing and priority date of the parent application. The subject matter of the divisional cannot extend beyond the disclosure of the as-filed parent application. It is also possible to file a divisional application based on an earlier divisional.