In principle, one patent application shall be filed for each invention. However, if there are two inventions that belong to the same broad concept of invention, then one patent application may be filed. The so-called broad concept of invention refers to two or more inventions that are technically related to each other and contain one or more identical or corresponding special or specific technical features. Generally, unity of invention can be met if there is an inseparable relationship in utilization, for example, the invention of an article, the method and device for producing or using said article. However, in practice, the applicant sometimes could not determine whether his/her invention patent application has violated the unity of invention, and whether the technical features covered by the patent application belong to more than two inventive concepts. Hence, the patent system provides the division filing procedure, so that if a patent application has substantially two or more inventions, divisional application(s) can be filed upon receipt of a notice from the Examiner, or to be voluntarily filed by the Applicant. A divisional application can retain the filing date of the original application (parent application) and the benefit of priority claim thereof.
In order for an Applicant to flexibly use the divisional filing procedure to obtain better patent protection, a divisional application can be filed during the prosecution of invention patent application (namely, before or after filing a request for substantive examination at the primary examination stage, during the period of receiving an office action and responding thereto; after filing a petition of re-examination against rejection at primary examination state, or receiving an office action and responding thereto), or within three months upon receipt of Notice of Allowance for invention patent application. A divisional application shall continue the same examination stage of its parent application, either at the primary or re-examination stage when the application is divided from its parent application, to avoid the repetition of handling and examining procedures.
It should be noted that the content of divisional application shall not exceed the scope disclosed in the specification, claims or drawings of the parent application. As the divisional application reserves the same filing date of parent application, the content of its parent application will be applied as a criterion to determine that no new matter is added. If a divisional application is to be filed during the prosecution of the parent application, said parent application can be amended (without substantial change) by deleting or revising the specification, claims, or drawings thereof. But if a divisional application is to be filed after the allowance of the parent application, the parent application must not be amended because the allowed content will be published for issuance of a Letters Patent, so that the content of said divisional application shall come from the specification or drawings but not the claims of the parent application (i.e. the Applicant cannot file a divisional application by using/splitting the claims from an allowed parent application). Normally, the specification of divisional application can be fully or partly the same as that of its parent application. For any differences between their content, TIPO requests the Applicant to file an underlined text showing the differences (with explanation, if any) when filing the divisional application.
In summary, the patent division is mainly to overcome the objection or rejection due to unity of invention, yet it also provides the applicant a chance to seek patent protection for the disclosed content of the invention in the original application that has not been claimed. In addition, when the Examiner issues an examination opinion letter stating the claims that may and may not meet the patent requirements, the Applicant can take this opportunity to split out the claims doubted by the Examiner into a divisional application, so that the parent application shall be allowed as soon as possible, while making every effort to obtain the allowance of said divisional application. Furthermore, for a pharmaceutical invention application, it is required to apply for regulatory approval before the patented product can be put on market. As the invention may not be implemented in the period from the publication of granted patent to obtaining the market approval, the Patentee shall file a request for patent term extension but can enjoy only a one-time extension of term for each granted invention patent. In this regard, TIPO indicates that the extension examination guidelines have provided more options for patent term extension in terms of the regulatory approval, hence the applicant can make good use of divisional application(s) for patent layout and strategy. For example, the active ingredients of a same compound could contain different salts or hydrates that may apply for several regulatory approvals. Due to certain reasons, the Applicant has incorporated the same into one patent application at first, but later can consider to file divisional application(s) during the patent prosecution or upon receipt of Notice of Allowance. Therefore, under some circumstances, division filings become also one of the important strategies for obtaining patent protection.
