The term “continuation application” refers to an application that is based on an original patent application (often referred to as a “parent” application), and has the same priority date and specification as the parent. When an application is a continuation of a parent application, it “claims priority” to the parent application. Continuation applications are often filed so that an applicant may pursue claims to inventions that were disclosed but not allowed in the parent application. In the U.S. and some other countries, there are several types of continuation applications:continuation applications (a sub-class of continuation applications), divisional applications, and continuation-in-part (CIP) applications.
A continuation is a patent application filed by an applicant who wants to pursue additional claims to an invention disclosed in the parent application. The continuation uses the same specification as the parent application, claims the priority date of the parent, and generally names at least one of the same inventors as in the parent. This type of application is often filed when a patent examiner has allowed some but rejected other claims in an application, or where an applicant feels that he or she has not exhausted all useful ways of claiming different embodiments of the invention during the prosecution of the parent.
A divisional application, or simply a “divisional”, is filed when the parent application contains more than one distinct invention. If multiple inventions are disclosed in a single application, the applicant may pursue claims to one of the multiple inventions in the parent application, and pursue the other inventions in subsequent divisional applications. The divisional applications generally have the same specification as the parent applications, claim the priority date of the parent, but have a different set of claims. In the U.S., divisional applications often result when the patent Examiner issues a “restriction requirement”, which limits each patent application to a single invention. Divisional applications in Europe and Australia are equivalent to a continuation application in the U.S.
A continuation-in-part application (or CIP or CIP application), is an application to which the applicant has provided substantially the same specification as the parent application, but has disclosed additional subject matter that was not included in the parent. For a continuation-in-part application, claims to subject matter that was also disclosed in the parent are entitled to the parent’s priority date, while claims to the additional subject matter are only entitled to the filing date of the CIP application. CIP applications are generally used to claim enhancements that were developed after the patent application was filed.
For more info please see How to View Continuity Data in PAIR