CHAPTER IX: PATENTS OF ADDITION
This chapter introduces a special, useful type of patent for when you improve your own invention.
Section 54: Patents of addition
- (1) What it says: …where an application is made for a patent in respect of any improvement in or modification of an invention… (in this Act referred to as the “main invention”) and the applicant… has applied for… or is the patentee… the Controller may… grant the patent for the improvement… as a patent of addition.
- In plain English: You invent a new vacuum cleaner (the “main invention”) and file a patent. One year later, before it’s granted, you invent a new, improved filter for it.
- You can file a new application for the filter and “link” it to your main application, requesting it be a “Patent of Addition.”
- Why? The main benefit is that the inventive step of the filter is judged only against the main invention, not against all public knowledge. (See Section 56).
- (2) What it says: …where an invention, being an improvement… is the subject of an independent patent and the patentee… is also the patentee… for the main invention, the Controller may… revoke the patent for the improvement… and grant to the patentee a patent of addition…
- In plain English: You didn’t file the filter as a Patent of Addition. You filed it as a separate, independent patent. Now you have two patents (and two sets of renewal fees).
- This section allows you to go back to the Controller and say: “Please revoke my independent ‘filter’ patent and re-grant it as a Patent of Addition to my ‘vacuum’ patent.” This links them together and saves you the renewal fees for the filter patent.
- (3) What it says: A patent shall not be granted as a patent of addition unless the date of filing of the application was the same as or later than the date of filing of the application in respect of the main invention.
- In plain English: You can’t file a patent for an “improvement” before you’ve filed for the main invention. This is just a logical rule.
- (4) What it says: A patent of addition shall not be granted before grant of the patent for the main invention.
- In plain English: The Patent of Addition is dependent on the main patent. The Controller will not grant your “filter” patent until he has first granted your “vacuum” patent.
Section 55: Term of patents of addition
- (1) What it says: A patent of addition shall be granted for a term equal to that of the patent for the main invention… and shall remain in force… until the… cesser of the patent for the main invention and no longer…
- In plain English: The Patent of Addition expires on the exact same day as the main patent. It does not get its own 20-year term.
- Real-world example:
- Main Patent (Vacuum) Filing Date: June 1, 2025
- Main Patent Expiry Date: June 1, 2045
- Patent of Addition (Filter) Filing Date: June 1, 2027
- Patent of Addition Expiry Date: June 1, 2045 (It only has an 18-year term, linked to the main patent).
- (1) Proviso: …if the patent for the main invention is revoked… the… Controller… may order that the patent of addition shall become an independent patent for the remainder of the term…
- In plain English: What if your main “vacuum” patent is revoked (cancelled) in court for being “not new”? Does your “filter” patent die too?
- This proviso says no. You can ask the Controller to convert the Patent of Addition into a standard, independent patent. It will then survive for the rest of the original term (expiring on June 1, 2045, in our example).
- (2) What it says: No renewal fees shall be payable in respect of a patent of addition… but, if any such patent becomes an independent patent… the same fees shall thereafter be payable…
- In plain English: This is the biggest financial benefit. You do not pay any renewal fees for a Patent of Addition. You only pay fees for the main patent.
- However, if your main patent is revoked and your Patent of Addition is converted into an independent patent (per the proviso), you must start paying the annual renewal fees for it from that day forward.
Section 56: Validity of patents of addition
This section explains the special legal protection given to a Patent of Addition, which is its main advantage.
- (1) What it says: The grant of a patent of addition shall not be refused, and a patent… shall not be revoked… on the ground only that the invention claimed… does not involve any inventive step having regard to any publication or use of— (a) the main invention… or (b) any improvement…
- In plain English: This is the most important part. An “inventive step” (or “non-obviousness”) is a key requirement for a patent. An invention is obvious if it’s just a small, logical change to something already known (the “prior art”).
- This section says that when judging the “inventive step” of your Patent of Addition, the main invention is NOT considered prior art.
- Real-world example:
- You invent a “3-legged stool” (Main Patent).
- Later, you invent a “4-legged stool” (Patent of Addition).
- A competitor tries to revoke your Patent of Addition, arguing: “The 4-legged stool is obvious! It’s just a simple, obvious improvement on the 3-legged stool.”
- This section blocks that argument. The law will not allow the Patent of Addition to be cancelled just for being an “obvious improvement” on the main invention. This allows you to protect small, iterative improvements that might otherwise fail the “inventive step” test.
- (1) What it also says: …and the validity of a patent of addition shall not be questioned on the ground that the invention ought to have been the subject of an independent patent.
- In plain English: This provides another legal shield. An opponent cannot try to cancel your Patent of Addition by arguing, “This invention is so good it should have been its own separate patent.” That is not a valid reason for revocation.
- (2) What it says: …in determining the novelty of the invention… regard shall be had also to the complete specification in which the main invention is described.
- In plain English: This clarifies the “novelty” (or “newness”) test. While the main invention can’t be used to attack your inventive step, it is used to judge novelty.
- This means the Patent of Addition must still be new. It cannot claim the exact same thing that was already described or claimed in the main patent. It must be a new modification or improvement.