Can You Patent an Improved Version of an Already Patented System in India?

One of my clients recently had a case which I am explaining below and if you are stuck in such similar situation, here is what to do.

Note: Due to attorney-client privilege, I cannot disclose complete case details or identify the actual parties involved. However, I am sharing the essential facts and legal approach so that if you find yourself in a similar situation, you can understand the available solutions and legal remedies.

TL;DR: Yes, you can patent an improved version of an existing system in India. Your invention must show new technical features that were not disclosed before, and those improvements must involve an inventive step—not just obvious tweaks. Even if the broad concept is similar, a patent can protect the specific improvements you’ve made.

Rohan Mehta, an engineer from Lucknow, spent over two years refining a smart irrigation control unit that paired soil sensors with a mobile app. His system offered encrypted data logging, fail-safe valve overrides, and an offline-first architecture—features not found in any off-the-shelf product. Before filing a patent, he unearthed an older patent held by Larsen & Toubro’s agri-division. That earlier patent described a basic idea of sensor-based irrigation. No detailed architecture. No security layer. The first advocate he consulted told him flatly: “The concept is already protected. You can’t file.” That advice nearly made him abandon the project. Later, Rohan approached the office of Advocate Sudhir Rao for a second opinion. Advocate Sudhir Rao and his team dug deeper. They mapped out the specific technical differentiators—encryption handshake, local caching logic, and a novel sensor self-calibration routine. His office argued that these were undisclosed, non-obvious improvements, and that Rohan’s innovation deserved protection under a patent of addition strategy. Within weeks, a professionally drafted patent application was filed with claims carefully directed at the improvements. The patent office issued an encouraging first examination report, and Rohan now holds enforceable rights over his distinct contributions.

Key Facts of the Case

• The client’s system was a hardware-plus-app combination for precision irrigation—with unique security and offline capabilities.
• An earlier patent by Larsen & Toubro existed, but it only broadly described a sensor-based irrigation concept without detailing implementation.
• A prior art search confirmed the older patent lacked the client’s encryption, fail-safe mechanisms, and sensor calibration methods.
• The client’s technical features were not obvious extensions; they solved specific problems in data integrity and device reliability.
• The patent filing strategy focused on Section 54 of the Patents Act (patent of addition) to claim the improvements without infringing the main patent.
• The claims were drafted to cover the inventive step clearly, and the examination report was positive.

The Direct Legal Answer

Can I still obtain a patent in India if my invention is an improvement over an existing patented system?

Yes. The Patents Act, 1970 explicitly allows patents for improvements or modifications of an existing invention, under Section 54 as a patent of addition. The improvement must satisfy the usual criteria: novelty, inventive step, and industrial applicability. The patent will protect only your novel features—not the original invention.

How different do my technical features need to be for the invention to be considered novel and involve an inventive step?

There’s no fixed percentage. The improvement must not be obvious to a person skilled in the art, considering what was already known at the filing date. Even a single technical advantage—like significantly better security, lower power consumption, or a new hardware integration—can qualify if it’s not a mere workshop improvement. The Patents Act defines inventive step under Section 2(1)(ja) as a feature that makes the invention non-obvious.

If the overall concept is similar but my implementation and security architecture are substantially different, could I patent only those improvements?

Absolutely. You can seek a patent of addition for the specific improvements while the original patent exists, or file an independent patent with claims limited to your new contributions. The claims must clearly define the inventive features, so a patent attorney will draft them to avoid overlapping with the earlier patent.

Should I redesign the system further before filing, or is it better to file improvement claims?

Do not redesign merely to escape the earlier patent if your current improvements are already technically sound. File improvement claims now to secure a priority date. You can always file further applications for subsequent developments. Waiting or redesigning unnecessarily can let competitors enter the space.

Advice in Such Cases

Consult with Lawyer: The very basic and important step to start is talk to Lawyer / advocate. You should not hesitate in paying his consultation fee i.e. might be in range of Rs. 10,000 to 50,000 depends case to case. He is helping you in this situation to come out. He is expert in the domain and can help you explain the procedure which you might have never explored. A good lawyer can get the issues resolved much faster than you think.

Before you share your idea with anyone—even potential investors—have them sign a non-disclosure agreement. Public disclosure before filing can destroy novelty. And here’s the thing: do a thorough prior art search early. Many inventors skip this and later find their application rejected.

Engage an advocate who regularly handles patent prosecution. This area involves nuanced claim drafting and an understanding of patent office objections that a general practitioner won’t have. A specialist can structure your claims to maximize protection without stepping on the earlier patent.

Applicable Sections of Law

• Section 2(1)(j), Patents Act, 1970 – Defines “invention” to mean a new product or process involving an inventive step and capable of industrial application.
• Section 2(1)(ja), Patents Act, 1970 – Defines “inventive step” as a feature that makes the invention not obvious to a person skilled in the art.
• Section 54, Patents Act, 1970 – Provides for patents of addition for any improvement in or modification of an invention already patented or for which a patent application has been filed.
• Section 10(4), Patents Act, 1970 – Requires that every complete specification fully describe the invention and end with claims defining the scope of protection.

Limitation Period

Patent filing itself has no limitation period under the Limitation Act, 1963—it’s an application process. But priority is everything. If you publicly disclose your improvement before filing, you lose novelty. For enforcing a granted patent against infringement, the limitation period is three years from the date of infringement under Article 88 of the Limitation Act. Missing that window can bar your suit. If you suspect infringement, act fast.

Interim Reliefs Available

If you later need to enforce your improvement patent and someone is copying it, you can seek an interim injunction under Order 39 Rule 1 and 2 of the Civil Procedure Code, 1908. Section 108 of the Patents Act also empowers courts to grant injunctions and order damages or accounts of profits in infringement suits. In urgent cases, ex-parte ad-interim injunctions can stop the infringer immediately, even before they are heard. Courts also often appoint local commissioners to seize infringing goods. Swift action preserves the commercial value of your patent.

If You Are the Victim

• If you discover someone has copied your improved system, document everything—screenshots, product listings, and any communication.
• Contact a patent litigation specialist immediately. Do not send a legal notice yourself without professional drafting.
• Preserve evidence of your invention’s development timeline, including dated lab notes, prototypes, and emails.
• If the infringer is a larger entity, be prepared for a countersuit challenging your patent’s validity—so have your prior art analysis ready.
• Consider whether a licensing deal might be a faster commercial resolution than litigation.

Documents You Must Keep Ready

• Aadhaar card and PAN card of the inventor(s).
• Complete technical disclosure—detailed description, diagrams, flowcharts, and source code if software-related.
• Prior art search report including the earlier patent and any other relevant publications.
• Proof of concept or prototype test results.
• Form 1 (application for grant of patent) and Form 2 (provisional or complete specification).
• Inventor’s assignment deed if the applicant is a company.
• NDA copies if any discussions with third parties occurred.

What Evidence Is Required?

• Primary evidence: the complete specification with claims exactly defining the improvement’s novel features.
• Drawings and schematics illustrating the new hardware or software architecture.
• Comparative data showing how your system outperforms the earlier patented invention.
• Expert affidavits from domain specialists confirming non-obviousness.
• Laboratory or field test reports that back your technical advantage claims.
• Copies of all correspondence with the patent office and examination reports.
• If an infringement case arises, the infringing product, purchase receipts, and packaging become crucial secondary evidence.

How Courts Typically Approach Such Cases

Indian courts look closely at the claims in both patents. They won’t simply compare broad titles. A judge will examine whether the later invention’s features, taken as a whole, were taught by or obvious from the earlier patent. In improvement patent disputes, courts often appoint scientific advisers. If your claims are narrow and clearly directed at a technical problem not solved by the earlier patent, you stand on solid ground. The Delhi High Court, which handles many IP matters, has consistently upheld patents of addition when the inventive step is clearly demonstrated.

Timeline of Legal Process

• Patent filing to publication: 18 months from filing date (or priority date) – the application is published in the patent journal.
• Request for examination: Must be filed within 48 months from priority date. Examination typically begins 1–2 years after request.
• First examination report (FER): Usually issued within 6–12 months after examination request. You get 6 months to respond.
• Grant or hearing: If objections are resolved, patent grants. Otherwise, a hearing is scheduled, and a decision follows in 3–6 months.
• Infringement suit: If needed, from plaint to trial can take 2–5 years, but interim orders are usually obtained within weeks.

Understanding the Costs

The total cost of a matter like this varies significantly from one case to the next — it depends on the complexity of the dispute, the forum involved, the number of hearings, and the specific facts of your situation. There is no single fixed figure that applies to everyone.

A professional advocate can give you an accurate estimate only after reviewing all your facts and documents in a consultation.

Can the Matter Be Settled Out of Court?

Yes. Many patent disputes end in licensing agreements or cross-licensing deals rather than trial. Mediation and conciliation under Section 89 of the CPC are viable—especially in commercial IP matters before the Delhi High Court’s mediation centre. The Patents Act also has provisions for compulsory licensing under specific conditions, though that’s a different scenario. For an improvement patent, if you face opposition or infringement threats, a negotiated settlement where both patent holders agree on royalties often preserves business relationships and avoids years of litigation.

Common Mistakes People Make

• Not conducting a thorough prior art search before investing in development. You risk reinventing the wheel.
• Drafting claims too broadly—this invites overlap with the earlier patent and grounds for rejection.
• Publicly demonstrating the improvement at an expo or on a website before filing the patent application, thereby destroying novelty.
• Believing that a small feature addition automatically qualifies—it must be non-obvious, not just a routine tweak.
• Engaging a lawyer who doesn’t regularly handle patent prosecution. Domain-specific experience shapes how claims are structured to survive examination and withstand later challenges.
• Failing to file a provisional specification early. The first-to-file system rewards speed, even if you refine the invention later.

FAQs People Normally Have

Will my improvement patent be valid if the original patent expires? Yes, a patent of addition can survive the main patent unless it is specifically revoked, but it normally expires with the main patent. You can also file an independent patent for the improvement with a separate term of 20 years.

Can I sell or license my improvement patent without the main patent holder’s permission? You can sell or license your improvement, but your licensees might still need a license under the main patent to practise the full invention. Cross-licensing is common.

What if my improvement is only a software feature? Software per se is not patentable under Section 3(k) of the Patents Act, but if your improvement has a technical effect—like better hardware control or data security—it may be patentable. Drafting must demonstrate the technical contribution.

Can I file a patent of addition after the main patent is granted? Yes, you can file a patent of addition at any time after the main patent is granted, as long as the improvement is new and involves an inventive step. The term will match the unexpired term of the main patent.

This article is general legal information, not legal advice. Consult a qualified advocate about your specific situation.

Advocate Sudhir Rao, Supreme Court of India