What Constitutes Patent Infringement
Patent infringement occurs when a person without the patentee's authorization performs any act that falls within the scope of the exclusive rights granted under Section 48. Infringement is a strict liability tort - intent is not required.
Types of Infringement
1. Direct Infringement
When the defendant directly performs the infringing act - making, using, selling, offering for sale, or importing the patented product or using the patented process.
2. Indirect/Contributory Infringement
While the Indian Patents Act does not explicitly address contributory infringement, courts have recognized it in certain circumstances:
- Supplying essential components for infringing products
- Actively inducing others to infringe
- Based on common law principles and tortious liability
3. Induced Infringement
Intentionally encouraging or instructing another to infringe the patent, though not directly performing the infringing act.
Literal Infringement vs Doctrine of Equivalents
Literal Infringement
Literal infringement occurs when the accused product or process falls squarely within the language of the patent claims - every element of at least one claim is present in the accused product/process.
For literal infringement, each and every limitation in the claim must be found in the accused device/process. If even one element is missing, there is no literal infringement (though there may still be infringement under doctrine of equivalents).
Doctrine of Equivalents
The doctrine of equivalents extends patent protection beyond the literal claim language to cover products/processes that perform substantially the same function, in substantially the same way, to achieve substantially the same result.
The Triple Identity Test (Function-Way-Result)
- Function: Does the accused element perform the same function as the claim element?
- Way: Does it perform the function in substantially the same way?
- Result: Does it achieve substantially the same result?
The Delhi High Court applied the doctrine of equivalents, holding that minor variations made to avoid literal infringement do not escape liability if the accused device performs substantially the same function in substantially the same way to achieve the same result.
Limitations on Doctrine of Equivalents
- Prosecution History Estoppel: Cannot reclaim scope surrendered during prosecution
- Prior Art Limitation: Cannot interpret claims to cover the prior art
- All Elements Rule: Must apply test element-by-element, not to claim as a whole
- Dedication to Public: Matter disclosed but not claimed is dedicated to public
Defenses to Infringement - Section 107
The defendant's product/process does not fall within the scope of the patent claims - neither literally nor under doctrine of equivalents. This requires detailed claim construction and comparison.
The patent is invalid and should be revoked. All grounds for revocation under Section 64 can be raised as defenses:
- Wrongfully obtained
- Not an invention under Section 3
- Lack of novelty (prior publication/use)
- Obviousness (lack of inventive step)
- Insufficient description
- Non-disclosure under Section 8
- Obtained by misrepresentation
This exemption allows generic manufacturers to conduct R&D and prepare regulatory submissions before patent expiry, enabling "day-one" launch upon expiration.
Importation of patented products by any person from a person duly authorized to produce and sell or distribute the product is not infringement. This implements international exhaustion.
Under common law principles (though not explicitly stated in the Act), use purely for research and experimentation on the patented invention itself may not constitute infringement.
A person who was using the invention before the priority date may have prior user rights to continue such use, though this is technically a ground for revocation rather than a defense per se.
Invalidity as a Defense
Patent invalidity is both the strongest sword and shield in patent litigation. A defendant can challenge validity either as a defense or through a counterclaim for revocation.
Key Grounds Under Section 64
| Ground | Section | What Must Be Shown |
|---|---|---|
| Anticipation by Publication | 64(1)(a) | Prior publication anywhere in the world before priority date |
| Prior Public Knowledge/Use | 64(1)(b) | Publicly known or used in India before priority date |
| Obviousness | 64(1)(f) | Obvious to POSITA having regard to prior art |
| Non-Patentable Subject Matter | 64(1)(d) | Falls under Section 3 exclusions |
| Insufficient Description | 64(1)(h) | Complete specification does not sufficiently describe invention |
| Section 8 Non-Disclosure | 64(1)(m) | Failure to disclose foreign filing information |
The defendant challenging validity must prove invalidity on the balance of probabilities. However, there is no presumption of validity in Indian law as exists in some other jurisdictions - validity must be established based on evidence.
Remedies for Patent Infringement
1. Injunction
The most powerful remedy - an order restraining the defendant from continuing infringing activities.
Interim/Interlocutory Injunction
Granted pending trial based on three principles:
- Prima Facie Case: Plaintiff shows triable issue of infringement and validity
- Balance of Convenience: Greater harm to plaintiff if denied than to defendant if granted
- Irreparable Injury: Monetary compensation would be inadequate
Permanent Injunction
Granted after trial upon finding of infringement and validity. Generally mandatory unless:
- Public interest considerations outweigh
- Patentee has shown willingness to license
- Monetary damages adequate
2. Damages or Accounts of Profits
The patentee can elect between:
- Damages: Compensation for loss suffered - lost profits, price erosion, reasonable royalty
- Accounts of Profits: Defendant must account for and surrender profits made from infringement
Under Section 111, if the defendant proves they were not aware and had no reasonable grounds to believe the patent existed, no damages or accounts of profits shall be granted. However, an injunction can still be granted. Marking products with patent number provides constructive notice.
3. Delivery Up/Destruction
Order requiring defendant to deliver up or destroy infringing goods and articles used to make them.
4. Costs
Successful party generally entitled to costs of litigation.
John Doe / Ashok Kumar Orders
John Doe orders (called "Ashok Kumar" orders in India) are injunctions against unnamed defendants. They are particularly useful when the identity of infringers is unknown or when there are numerous small-scale infringers.
The Delhi High Court granted an Ashok Kumar order in a pharmaceutical patent case, restraining unnamed defendants from manufacturing and selling infringing products. The court authorized local commissioners to conduct raids and seizures.
Procedure for John Doe Orders
- File suit against "John Doe" or "Ashok Kumar" and unknown defendants
- Demonstrate strong prima facie case of infringement
- Show that infringers are unknown or too numerous to name
- Court may appoint local commissioner for execution
- Publication of order to provide notice
- Identified defendants can be added to suit
Uses in Patent Litigation
- Multiple small-scale counterfeiters
- Online/e-commerce infringement
- Trade fair/exhibition seizures
- Preventing launch of generic products