Patent Invalidity Search: Find Prior Art to Challenge a Patent
A patent invalidity search looks for earlier publications, products and patents that show a granted or published patent should never have been granted. The result is a claim-by-claim prior art report you can use in an opposition, a revocation petition or a settlement talk. We prepare the search brief, coordinate the search and organise the evidence.
What it is
An invalidity search is a targeted hunt for prior art against one specific patent. Unlike a general patent search, you start with the claims of a patent that already exists, and look for a document or earlier use that discloses the same thing, or makes it obvious, before the patent’s priority date.
The Patents Act, 1970 gives this work three uses. Any person can oppose a published application before grant under Section 25(1). A person interested can oppose within one year after the grant is published under Section 25(2). And any interested person, or the Central Government, can petition for revocation under Section 64, or counter-claim for it when sued for infringement.
Who it applies to
You have received an infringement notice
Say a competitor writes that you infringe their patent. A strong patent invalidity search can show the patent is weak, and it strengthens your hand before anyone files in court.
You want to remove a blocking patent
A granted patent sits across your product roadmap. You want to challenge it through post-grant opposition or revocation rather than design around it.
You are doing due diligence
You are buying, licensing or investing against a patent portfolio. You want to know how strong each patent really is before you pay for it.
Why it matters
Strong prior art wins cases
A patent invalidity search matters because novelty and obviousness are the two grounds that count most in practice. Both need documents. A good search finds them before the other side does.
It sets your strategy
If the search turns up a clear anticipating document, you can oppose or negotiate with confidence. If it finds nothing, you save the cost of a weak challenge and look at design-around options instead.
It shapes the timing
The route you can use depends on where the patent stands: pending after publication, granted for less than a year, or granted for longer. The search tells you what evidence you have before that clock matters.
Documents required
About the patent
- Patent or application number, or the claims text
- Filing date, priority date and publication details
- Patent Office status and any hearing or examination reports
About your side
- Your product or process description, in confidence
- Any earlier products, catalogues or papers you know of
- Any notice, legal correspondence or suit papers received
For a filing
- Authority letter and details of the applicant or opponent
- Copies of the prior art documents with dates
- Statement of case, prepared for an advocate or patent agent to sign
How it works
Read the claims and the file
We study the claims, specification and prosecution history of the patent, including how the claims narrowed during examination. The key priority date is fixed first, because only earlier material counts.
Run the search
The search covers patent databases such as IP India’s InPASS, WIPO Patentscope and the EPO’s Espacenet, plus journals, theses, standards, product manuals and web archives. Only dated, citable documents count.
Build the claim chart
Each claim is broken into features, and each feature is matched to a passage in a prior art document. Gaps are marked honestly, so you know where an argument is strong and where it is thin.
Hand over the report and plan the next step
You get the report with copies of every document. If it supports a challenge, we prepare the file for a patent agent or advocate to turn into a representation, opposition or revocation petition, and we coordinate the filing.
Which route fits your situation
| Where the patent stands | Route | Who can use it |
|---|---|---|
| Published, not yet granted | Pre-grant opposition, Section 25(1), representation in Form 7A, no official fee | Any person |
| Granted, within one year of grant publication | Post-grant opposition, Section 25(2), Form 7 | A person interested |
| Granted, any time | Revocation petition in the High Court, Section 64 | Any interested person or the Central Government |
| You are sued for infringement | Counter-claim for revocation, Section 64 | The defendant |
For help with the grant side of the process, see our patent registration service. If you only need to check a new idea against existing patents, a patent search is the right starting point.
Timelines
Pre-grant window
Opposition under Section 25(1) opens after the application is published, which happens 18 months from filing unless early publication is requested. It stays open until the patent is granted, so move early.
Post-grant window
Section 25(2) allows opposition within one year of the date grant is published. After that, revocation under Section 64 is the main route, filed in the High Court.
The search itself
Most of the work is finding and dating documents. We give you a schedule when you share the patent number, because the claims and the technology decide the time.
What happens if you delay
The easy route closes
Once the one-year post-grant opposition window ends, you are left with revocation or a counter-claim, both in court and both costlier.
Evidence disappears
Here is the catch: web pages change, product listings come down and catalogues go out of print. Dated copies of earlier material need to be captured while they exist.
You negotiate blind
Without a search, a licensing or settlement offer is based on the other side’s account of the patent. With one, you know how strong it is.
Frequently asked questions
What grounds can invalidate an Indian patent?
Section 64(1) lists them. The main ones are lack of novelty because the invention was publicly known or published before the priority date, obviousness or lack of inventive step, subject matter that is not an invention, insufficient description and claims not clearly supported. Prior art search mainly supports novelty and obviousness. We map each claim to the ground it can realistically support.
Who can challenge a patent, and where?
Any person can oppose before grant under Section 25(1). A person interested can oppose within one year after grant is published under Section 25(2). Any interested person, or the Central Government, can seek revocation under Section 64 in the High Court, since the appellate board was abolished in 2021. A defendant sued for infringement can counter-claim for revocation.
Is an invalidity search the same as a patent search?
No. A patent search checks whether a new idea is patentable or free to use. An invalidity search starts from one granted or published patent and looks for earlier art that defeats its specific claims. The reports are built differently: an invalidity report is organised claim by claim. A general patent search will not give you the claim chart a challenge needs.
Does the search guarantee the patent will be revoked?
No. A search finds evidence; the Controller or the High Court decides whether it is enough. We cannot promise an outcome. What we give you is a dated, organised file that a patent agent or advocate can use, with the strong and weak points marked clearly, so you can decide knowing where you stand.
Which databases do you search?
Patent databases include IP India’s InPASS, WIPO Patentscope and the EPO’s Espacenet, along with journals, theses, standards, manuals and archived web pages. Non-patent literature matters, because many successful challenges rest on a paper or product that was never patented. Every document we cite is dated and can be copied for the file.
Do I need an advocate or patent agent?
For the filing itself, yes. Oppositions are filed by a person or a registered patent agent, and revocation petitions and counter-claims are in the High Court, where a practising advocate signs and appears. We prepare the search, the evidence file and the draft papers, and coordinate. Where a qualified professional must sign, one does.
Can I search an application that is not yet published?
No. An application is published 18 months from filing unless early publication is requested, and until then its content is not public. Pre-grant opposition becomes available only after publication. If a competitor’s application is coming up, we can set a watch so the search starts when it appears.
What does an invalidity search cost?
The search has no official fee, so the cost is our professional fee, which we quote before you commit and which depends on the number of claims and the field. A filing has its own official fees: Form 7 for post-grant opposition is ₹2,400 for a natural person or start-up and ₹12,000 for others, while a Form 7A representation has no fee.
What it costs
Our fee plus the government fee that applies to your case, quoted before you commit. Tell us the situation and we will price it exactly.
Official fees for reference: a pre-grant representation (Form 7A) carries no fee. Form 7 for post-grant opposition is ₹2,400 e-filed by a natural person or start-up and ₹12,000 for others. A revocation petition in the High Court carries court fees that vary by court. The search itself has no official fee.
Ready to begin?
Share the patent number and what you want to achieve, and we will scope the search and tell you which route is open.