“The scope of improvement is infinite, precisely because perfection is unattainable”.
Often, after filing a patent for an invention, additional modifications and improvement of the invention surface. The improvements or modifications may take place as a result of further experimentation to improve the invention, or as a result of feedback received from the industry.
In such a scenario, where the invention is already protected by a patent, the improvement or modification over the original patented product or process may be protected by a “Patent of Addition” in India.
“Patent of Addition” falls under Sections 54, 55 and 56 of the Patents Act, 1970. A patent of addition facilitates the addition of new subject matter in the form of modifications and improvements to an existing disclosure of the parent application, while retaining the priority date for claims based on the original disclosure by the patentee.
Filing a new patent application is another option, but the priority date of the new patent will be different from that of the previously filed application (or parent application). The claims of the patent of addition inherit the priority date of the parent application. As a result, claims in the patent of addition can have a priority date that is before the filing of the patent of addition.
However, the applicant must be the same for the parent patent application and the patent of addition. If the improvement or modification involves an additional applicant, a patent of addition may not be pursued.
A patent of addition effectively enables an applicant to make incremental improvements and add embodiments that might not justify their own patent applications without needing to file parallel applications. More specifically, the applicant need not pay a renewal fee for a patent of addition, thereby saving costs.
A patent of addition is a suitable and attractive option for applicants to add additional features onto previously filed patent applications, it may not always be the right tool for the job, it has its own disadvantages.
In contrast to the perception that the patent of addition inherits the priority date of a parent application, certain claims may have their own priority dates. Only the claims fully supported by the disclosure of the parent patent application are entitled to the priority date of the parent patent application.
A term of a patent is 20 years from the date of filing of patent application and the term of patent of addition is limited to its parent application’s term. For example, a patent of addition filed in 2017 that claims priority to a parent application filed in 2013 will expire in 2033, as opposed to 2037 if a new patent application was filed instead of patent of addition application. This reduced patent tenure might result in loss of significant revenue from products or methods that pertains to the new patent claims supported by the patent of addition.
Further, introduction of new claims in the patent of addition may leave the door open for an opponent to assert the invalidity of parent application if the disclosure in the parent application do not justify the additional claims. In situations where support for the new subject matter of the patent of addition is not clearly set out in the parent application, it may be advantageous to file a separate application to utilise the distinctiveness of the new claims, and to obtain the benefit of a full patent term.
Accordingly, a patent applicant must look at all the pros and cons before making a decision to apply for a patent of addition.