Section 91 of the Patents Act, 1970
Licensing of related patents
Lets a patentee who cannot work its own patent without infringing another patent ask the Controller for a licence under that other patent.
Official legal text
The verbatim statutory text of this provision is reproduced from the official source and checked by our legal reviewer before it is published here. Until that check is complete for this page, read the exact wording directly from the official source linked below — it is the only version that governs.
This is a simplified explanation. Where it differs from the official text of the provision, or from an applicable Gazette notification, the official text and the notification prevail.
What this section says, in plain language
Technology builds on technology. A later invention often cannot be used without touching an earlier patent, and the two owners may not agree on terms. Section 91 provides a way out of that deadlock. It deals with what are commonly called dependent or related patents, and unlike Section 84 it is not tied to any three-year waiting period.
The applicant must be the patentee or licensee of one patent who cannot work that patent efficiently, or to the best advantage, without infringing another patent. The application is made to the Controller for a licence under that other patent, on Form 17 under Rule 96 with the fee prescribed in the First Schedule. The applicant has to show a genuine technical dependence, not merely that the other patent would be convenient to have.
Two conditions must be satisfied before the Controller makes an order. First, the applicant must be able and willing to grant, or procure the grant of, a licence to the other patentee and its licensees in respect of the applicant's own invention, on reasonable terms. In other words, the applicant must be ready to cross-license. Second, the other patentee must be unable or unwilling to grant a licence to the applicant on reasonable terms, which is why a documented licence request and refusal matters.
A licence granted under this section is not freely transferable. It cannot be assigned except along with an assignment of the patent that made the applicant dependent in the first place. This keeps the licence attached to the technology it was granted to support.
In practice this section is a bargaining tool as much as a remedy. The prospect of the Controller ordering a cross-licence on terms he settles often persuades two patentees to negotiate their own agreement, which is usually faster and gives both sides more control over confidentiality, field of use and territory.
Why this section matters
Patentees and licensees whose improvement or downstream invention is blocked by an earlier patent, and owners of blocking patents.
Once the blocking patent is in force and a negotiated licence has been refused or has stalled, at any time and without the Section 84 waiting period.
A right to apply for a licence under a blocking patent, and an expectation that the applicant will cross-license its own invention in return.
The applicant's own patent may stay commercially useless, while working the invention anyway would amount to infringement of the blocking patent.
How it works in practice
An improved braking module blocked by an earlier patent
Kestrel Robotics Pvt Ltd holds an Indian patent on a regenerative braking module for warehouse robots. Its module cannot function without a wheel-hub sensor arrangement covered by an earlier patent owned by another manufacturer. Kestrel writes twice offering a cross-licence: access to the hub sensor patent in exchange for a licence to Kestrel's braking improvement, with a royalty either way. The other company does not reply to the first offer and refuses the second without proposing terms. Kestrel applies under Section 91 on Form 17. It files an engineering report showing that no non-infringing hub arrangement gives the same efficiency, its correspondence trail, and a signed statement that it is ready to grant a cross-licence on reasonable terms. The Controller has to be satisfied that Kestrel is genuinely able and willing to cross-license, and that the other patentee is unable or unwilling to license on reasonable terms. If a licence is ordered, Kestrel cannot assign it separately from its own braking patent.
Simplified illustration only. Actual legal outcomes depend on the facts.
Key points to remember
- Designed for dependent patents where one invention cannot be worked without infringing another.
- No three-year waiting period applies, unlike Section 84.
- The applicant must be able and willing to cross-license its own invention on reasonable terms.
- The other patentee must be unable or unwilling to grant a licence on reasonable terms.
- The licence cannot be assigned except along with the patent it supports.
- Applications are made on Form 17 under Rule 96 with the prescribed fee.
Common mistakes and misunderstandings
- Applying without a documented licence request. The Controller needs to see that the other patentee was approached and would not license on reasonable terms.
- Claiming dependence that is only commercial. The applicant must show it cannot work its patent efficiently or to the best advantage without infringing, usually with technical evidence.
- Forgetting the cross-licence obligation. An applicant unwilling to license its own invention back is unlikely to succeed.
- Assuming an order under this section can be sold on. It travels only with the applicant's own patent.
Connected provisions
A section tells you what the law is. A rule tells you how the Patent Office runs it from day to day. The two are kept apart here so that a reader can quote the section accurately and then look up the current rule for the practical steps.
Forms, deadlines and fees
Forms are not set out in the Act. They are prescribed in the Second Schedule to the Patents Rules and are revised from time to time, so obtain the current version from the official website before filing.
- No three-year waiting period applies here; the application can be made while the blocking patent is in force.
Open the deadline calculator — and have every date confirmed against the current Rules before you rely on it.
The official fee for anything described on this page is set out in the First Schedule to the Patents Rules. It is not the same for every applicant, and it is not the same for online and physical filing, which is why no amount is stated here. How Indian patent fees work.
Related judgments
Case law is added slowly and deliberately. A summary is drafted, checked against the reported judgment and then reviewed before publication, because a wrong case note can mislead a reader badly. No summary for this provision has reached publication yet. How case notes are prepared.
Questions people ask about Section 91
How is Section 91 different from an ordinary compulsory licence?
Section 84 is about the public: whether demand is met, whether the price is affordable, and whether the invention is worked in India. Section 91 is about two patent owners in a technical deadlock. The applicant is itself a patentee or licensee whose invention is blocked by someone else's patent. There is no three-year wait, and the applicant is expected to offer a cross-licence in return. The remedy is aimed at unlocking a specific technology relationship rather than at correcting a market failure.
Do I have to offer a cross-licence to succeed?
In substance, yes. The Controller cannot make an order unless he is satisfied that the applicant is able and willing to grant, or to procure the grant of, a licence to the other patentee and its licensees in respect of the applicant's invention on reasonable terms. So an applicant should come to the proceeding with a clear, written cross-licence offer and the authority to make it. If the applicant's own patent is itself licensed exclusively to a third party, that complication should be sorted out before applying.
What evidence shows that one patent blocks another?
Usually a claim-by-claim technical analysis. You map the features of your product or process against the claims of the other patent to show that working your invention efficiently necessarily uses those claims. Independent expert evidence helps, as does a design-around study showing that alternatives are unavailable, materially worse, or uneconomic. Correspondence in which the other patentee has itself asserted its patent against you can also support dependence, along with regulatory or standards documents where they apply.
Is another patent blocking your own invention?
MYCrave assesses dependency, prepares the cross-licence offer and files the Section 91 application on Form 17.
You will be speaking with MYCrave Consultancy & Services, the firm that operates this platform. General questions are answered free; matter‑specific work is quoted before anything is done.