Article 42, Paragraph 1 of the Implementation Rules of the Patent Law of our country stipulates: If a patent application includes more than one invention, utility model, or design, the applicant may, within a two-month period (i.e., the deadline for registration) from the date of receiving the notice of grant of patent rights from the State Council’s patent administrative department, file a divisional application to the State Council's patent administrative department. However, a divisional application cannot be filed if the patent application has been rejected, withdrawn, or considered withdrawn.

In practice, the purpose of filing a divisional application can generally be divided into two categories: passive divisional applications and active divisional applications.

1. Passive Divisional Application

A passive divisional application is the most common type, where the examiner points out a lack of unity in the examination opinion. The applicant retains only one invention or creation in the original application and files a divisional application for the other inventions that lack unity. This is a reactive measure when the original application cannot meet the requirements due to unity issues.

2. Active Divisional Application

In situations where the case has not yet been completely classified—i.e., it has not been rejected, withdrawn, or considered withdrawn—the agent may file a divisional application proactively to seek more reasonable and comprehensive patent protection for the applicant.

The following discussion mainly focuses on the second type, active divisional applications. Based on practical experience, the author suggests several scenarios in which a divisional application can be used to maximize the applicant’s interests.

Case 1

During the patent examination, there may be significant differences between the applicant and examiner on the novelty and inventiveness of certain technical solutions in the claims. After multiple attempts to negotiate with the examiner, if a broad authorization cannot be obtained, the applicant may modify the claims to meet the examiner’s requirements. Meanwhile, the contentious claims can be split into a divisional application. This way, the applicant seeks a chance for the disputed technical solution to be granted after a second round of examination, at the cost of temporarily sacrificing part of the original application’s benefits.

However, this approach carries certain risks. The examiner reviewing the divisional application might be influenced by the examination approach, comparative documents, and results of the parent application.

To minimize the impact of the parent application’s examination on the divisional application, the agent should emphasize in the statement that the modification was only made to expedite authorization, avoiding arguments that the newly added technical features are the core inventive aspects.

Case 2

During the patent application process, if the applicant identifies an excellent direction for improvement but the company’s product has not yet been commercialized, or it is uncertain how competitors will design around it, the applicant may file for a broad protection range first and later develop multiple potential directions as independent claims. Independent claim 1 usually does not meet the inventiveness requirement, so the related dependent claims would also lack unity.

Once the case enters public examination, the applicant can file divisional applications based on their own products and those of competitors. This not only helps protect the applicant’s products but also creates multiple divisional applications targeting competing products.

For this situation, substantial effort must be put into drafting the parent application to ensure each solution can be independently divided and a divisional application can be filed accordingly.

Case 3

Sometimes, after filing a patent application, the claims may not match what the applicant truly wants to protect or may not correspond well with the most marketable technical solutions or the actual products. This could also happen when the scope of the claims doesn’t align with the competitor’s infringement.

A typical example is when the claims are written to protect a product’s technical range but the competitor may design around it. If the description was sufficiently detailed, the applicant can use divisional applications to adjust the application strategy, as long as the scope does not exceed what was originally disclosed, thus providing protection against potential infringement by competitors.

The need for proactive divisional applications is not limited to the above examples. Applicants may also file divisional applications according to their own needs.

Insight

In principle, the essence of the patent system is the exchange of disclosure for protection. For divisional applications, a good specification is crucial.

According to Article 51, Paragraph 3 of the Patent Law Implementation Rules, modifications made to an application after receiving an examination opinion should only address the defects pointed out in the notification. Therefore, for patent applications already under examination, modifications to the claims are constrained by this legal provision. By filing a divisional application, an applicant can protect important technical solutions that were disclosed in the specification but not included in the original claims.

Especially in the context of the "donation principle" clarified in Article 5 of the Supreme People’s Court’s interpretation on patent infringement disputes, divisional applications play a crucial role in avoiding a "passive donation" situation in future infringement disputes.

In practical writing, especially when the applicant requires protection for a product-related technical solution, it is necessary to communicate thoroughly with the applicant in the early stages to explore the technical solution in depth and create a high-value specification. This allows the applicant to later file divisional applications based on actual needs, ensuring effective protection of their products and preventing competitors from easily designing around them.