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Amendment of Patents


Date: 2023-11-16

Can an applicant or a patent agent amend a patent application if they discover any defects or wish to modify its content after they submitted the patent application documents to the Patent Office?


Article 33 of the Patent Law stipulates that an applicant can modify their patent application documents. However, the modifications must not exceed the scope as originally described in the specification and claims.

In addition to content restrictions, there are also time constraints for amendments to the patent application documents. Below, we provide an overview of the amendments which can be made.


I. Timeframe for Amendment of Patent Application Documents

Invention Patents: Applicants can request modifications to invention patent applications when filing a request for substantive examination and within three months from the date of receiving a notice from the State Council's patent administrative department indicating that the invention patent application has entered the substantive examination stage.


Utility Model or Design Patents: Applicants have a two-month window from the application date to request modifications to utility model or design patent applications.


It's worth noting that for invention patents, there are two opportunities for modifications. In most cases, to expedite the examination process or avoid forgetting, applicants often request substantive examination when filing a new invention patent application. In such cases, the "at the time of substantive examination request" opportunity for amendment cannot be used later.


II. Scope of Amendment to Patent Application Documents

Invention Patents and Utility Model Patents:
Amendments must not exceed the scope as originally described in the specification and claims.

It's important to note that neither the patent examination guidelines nor the Patent Law explicitly prohibit adding or modifying claims. This means that, within the bounds of the originally described specification and claims, new claims can be added or existing claims can be modified when amending patent application documents.

Design Patents: Modifications should not exceed the scope originally represented in the drawings or photographs.


III. Purpose of Amendment of Patent Application Documents

Firstly, amendments to patent application documents can address content defects that may have arisen at the time of submission, reduce subsequent examination opinions, and shorten the examination period. Within the original scope of the specification and claims, amendments can also be used to modify the original claims, thereby readjusting the scope of protection of the patent application.

Secondly, due to the rapid growth in the number of patent applications, multiple patent applications are submitted to the patent office every day. To secure an earlier filing date, applicants may choose to submit their patent application documents sooner rather than later, especially when time is limited, and then subsequently make amendments to ensure the protection of the applicant's rights.



The ability to amend patent application documents offers applicants flexibility in addressing defects and adapting to evolving circumstances. It is essential to understand the permissible timeframes and the scope of amendments, which vary for invention, utility model, and design patents. By making strategic amendments within the original specification and claims, applicants can optimize their applications, reduce examination challenges, and enhance the overall protection of their intellectual property rights. This approach is especially valuable in the context of the increasing volume of patent applications, where securing an early filing date can be of paramount importance.