What a granted patent family actually protects, and the five questions a licensee should ask

I spend a fair amount of time in conversations where a technically excellent engineer is evaluating a patent portfolio using assumptions that are, quietly, wrong. Not through any fault of theirs — patents are a legal instrument described in engineering language, and the two disciplines use several of the same words to mean different things.

So this is what a granted patent family actually gives you, written by someone who owns three of them and has had to learn where his own coverage stops.

1. There is no such thing as a world patent

A patent is a national right. It is granted by a national or regional office, and it can be enforced only in that jurisdiction. A "patent family" is not one right with international reach — it is a set of separate national rights descending from a common priority filing.

The PCT is frequently misunderstood on this point. A PCT application is a procedure, not a right. It preserves your ability to enter national phases and buys you time; it never grants anything. "PCT filed" on a slide means an option has been kept open, not that protection exists.

The practical consequence for anyone evaluating a portfolio: the only question that matters is the overlap between the jurisdictions where rights are in force and the jurisdictions where you manufacture, sell or import. A family with eight grants, none of them in your manufacturing territory, protects you nowhere that matters.

2. Claim 1 is the asset — not the title, not the abstract

The title tells you nothing. The abstract tells you almost nothing. The description tells you what the inventor thought they had.

The independent claims define the scope of the right, and claim 1 is usually the broadest. Everything else in the document is context for construing it. If you are assessing a patent and you have not read claim 1 word by word, you have not assessed the patent.

Two things about claims that regularly surprise engineers:

Claims narrow during prosecution. The claim that grants is frequently not the claim that was filed. Examiners cite prior art; applicants amend to distinguish. A family member granted in one jurisdiction and one granted in another may have materially different scope, because they were examined by different offices against different prior art. Reading the US claim and assuming the Japanese one matches is a common and expensive error.

Dependent claims are fallbacks, not extras. They add limitations. Their function is to survive if claim 1 is invalidated. A portfolio whose value rests on a broad claim 1 with no meaningful dependent structure is more fragile than its grant count suggests.

3. Granted does not mean valid

A granted patent is presumed valid. The presumption is rebuttable, and it is rebutted regularly.

Inter partes review in the United States, opposition at the EPO, revocation proceedings in India and elsewhere all exist to test grants against prior art the examiner did not find. A meaningful fraction of challenged claims are narrowed or cancelled.

This is not an argument against patents. It is an argument for reading the prosecution history — what the examiner cited, what the applicant argued, what was surrendered to get the grant. Statements made during prosecution can limit how a claim is later construed. That history is public, and it is the single most informative document in the file after the claims themselves.

4. Owning a patent does not mean you may practise it

The distinction that causes the most trouble in commercial conversations.

A patent is a right to exclude others. It is not a right to practise. Your invention may be an improvement on someone else's unexpired patent, in which case you may exclude them from your improvement while they exclude you from the underlying technology. Both patents are perfectly valid.

So patentability and freedom to operate are separate questions with separate answers. A licensee who assumes a granted patent guarantees clear commercial passage has skipped the FTO analysis, and FTO is the one that determines whether they can ship.

5. The five questions

If I were evaluating someone else's portfolio, these are what I would ask, in order:

One. Where is it actually in force, today? Not filed, not "pending", not "granted at some point" — in force, with annuities paid. Registers are public. Check them rather than the brochure. This is why my own register publishes a grant number and a grant date against every jurisdiction rather than a headline figure: the format is the claim. A list of numbers and dates can be checked in an afternoon, and a portfolio page that cannot be checked that way is asking to be taken on trust.

Two. How long is left? Term is generally twenty years from the earliest non-provisional filing, subject to maintenance fees and any adjustment. A family expiring in 2035 has nine years to run — which is a different asset from one expiring in 2028, and the difference should be in the price.

Three. What does claim 1 actually cover, per jurisdiction? Read them all. Assume they differ until you have confirmed they do not.

Four. Does the product actually fall within claim 1? A licensee is buying the right to exclude, and that right is only as useful as the overlap between the claim and the thing being sold. If the commercial product operates outside the claimed range — different parameters, different configuration — then the patent may not cover the product being licensed. Ask the question directly and expect a written answer. Any portfolio owner who has done the work will have one.

Five. What is the prosecution history? What was given up to obtain the grant, and how does that constrain construction?

What this means for how I present my own portfolio

I publish a complete register: three families, every jurisdiction named, every entry carrying its grant number and its grant date. Not a headline count — a list.

The distinction is not pedantry. A count is a claim about a portfolio; a list is a set of things that can each be looked up. It would be straightforward to present a larger, rounder number, and several portfolio pages do. The reason not to is entirely practical: the counterparty's IP counsel will pull the registers in an afternoon. What they find determines whether the rest of the diligence proceeds in good faith or in suspicion, and there is no recovering the second from the first.

A portfolio that survives an adversarial read is worth more than a larger one that does not. That is the only real argument for honesty in this context, and it happens to be sufficient.

Measure everything. Validate everything. Improve continuously.

Hemant K. Rohera is an inventor and engineer in Pune, India, sole named inventor on three granted patent families — bioelectronic medical devices, hybrid energy storage and vehicle power electronics — with grants in force in India, the United States, Japan, South Korea, Canada, Mexico, Australia, Vietnam, Saudi Arabia, South Africa, Germany, the United Kingdom, Switzerland, Russia and Kazakhstan. All three are available for licensing, assignment or joint development. The complete register is published at hrohera27.blogspot.com/p/patent-register.html; claim sets, prosecution histories and independent test reports are available under NDA. ORCID: 0009-0005-3275-1743

This article describes general principles of patent law for a technical readership. It is not legal advice, and patent practice differs by jurisdiction. Consult qualified counsel on any specific matter.

The complete patent register, with a grant number and grant date for every entry, and the research record, with abstracts and DOIs for the deposited notes, are published at hemant-rohera.vercel.app/patent-register.html and hemant-rohera.vercel.app/research.html.

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Hemant Rohera — Bioelectronics, Energy Storage and Power Electronics