1. Establishing Patent Rights and an Infringement Theory
Before filing, patent owners need enforceable rights and a factual basis for infringement.
Patent Ownership, Validity, and Standing
Under 35 U.S.C. § 281, a patentee may sue for infringement. Review issued patents, assignments, maintenance status, and licenses.
An exclusive licensee may need to join the owner unless it received substantially all patent rights. Section 282 presumes validity, subject to prior-art challenges. Disputed ownership may warrant a patent assignments review.
Claim Charts and Direct or Indirect Infringement
Under § 271(a), a product claim generally requires every limitation in the accused product, literally or by equivalence. Method claims require each step to be performed by or attributable to one entity, including through direction, control, or a joint enterprise.
Inducement (§ 271(b)) requires knowledge of the patent and intent to encourage direct infringement. Contributory infringement (§ 271(c)) concerns knowingly supplied components adapted for infringing use and lacking substantial noninfringing uses.
Claim charts link limitations to evidence. They are not mandatory with every complaint, but local rules may require later infringement contentions.
MIT attached claim charts to its October 9, 2026 complaint against AWS. Infringement remains alleged.
2. Technical Evidence Linking Patent Claims to Accused Products
Product records and claim charts identify features that may meet asserted limitations.
| Evidence | Litigation Purpose |
|---|---|
| Patent and assignment records | Ownership and standing |
| Claims and prosecution history | Claim scope |
| Product manuals and testing | Accused technical features |
| Claim charts | Element-by-element proof |
| Sales and licensing records | Potential damages |
| Prior art and PTAB records | Validity challenges |
Patent and assignment records
- Litigation PurposeOwnership and standing
Claims and prosecution history
- Litigation PurposeClaim scope
Product manuals and testing
- Litigation PurposeAccused technical features
Claim charts
- Litigation PurposeElement-by-element proof
Sales and licensing records
- Litigation PurposePotential damages
Prior art and PTAB records
- Litigation PurposeValidity challenges
Product Records, Testing, and Source Code
Manuals and testing can support infringement allegations. Source code may be obtained in discovery under a protective order.
Preserve product versions and test dates; design changes can affect the claim.
Expert Evidence and Anticipated Invalidity Challenges
Technical experts assess disputed limitations; damages experts examine sales and licenses. Prior art and Patent Trial and Appeal Board (PTAB) proceedings may expose validity risks.
A patent strategy review may clarify these risks.
3. Filing Patent Litigation in Federal Court
Patent jurisdiction alone does not establish proper venue or personal jurisdiction.
Federal Jurisdiction, Venue, and Complaint Requirements
Under 28 U.S.C. § 1338(a), federal district courts have original jurisdiction over patent-law actions; state courts cannot hear claims arising under federal patent law.
Under § 1400(b), a domestic corporation generally may be sued where incorporated, or where it infringed and maintains a regular and established place of business.
The complaint must identify patents, accused conduct, and plausible infringement.
Claim Construction, Discovery, and Expert Testimony
Courts construe disputed terms using claims, specifications, and prosecution histories, sometimes at a Markman hearing.
Discovery may cover source code, designs, and sales, subject to confidentiality protections. PTAB proceedings may affect timing.
4. Injunctions, Damages, and Limits on Recovery
Proving infringement does not automatically establish entitlement to injunctions or enhanced damages.
Preliminary and Permanent Injunctions
Preliminary relief under 35 U.S.C. § 283 generally requires likely success, likely irreparable harm, favorable equities, and public-interest support.
Under EBay v. MercExchange, permanent relief requires irreparable injury, inadequate legal remedies, favorable hardship balance, and public-interest support. Lost customers can be relevant.
Lost Profits, Reasonable Royalties, and Enhanced Damages
Section 284 provides at least a reasonable royalty. Lost profits require evidence linking infringement to lost sales.
For multi-component products, reasonable royalties generally reflect the patented features' value, not automatically all product revenue. Damages may be enhanced up to threefold; willfulness alone is insufficient.
Section 286 limits recovery for infringement more than six years before filing, not when suit may be filed.
Under § 287(a), failure to mark patented articles can limit pre-notice damages. Filing can provide notice; method-only claims may differ.
5. Patent Litigation Faqs
Can a patent owner sue without first sending a cease-and-desist letter?
Generally, yes. Marking or actual notice under § 287 may affect pre-suit damages.
Can a patent owner recover attorney's fees after winning?
Not automatically. Section 285 permits reasonable fees for the prevailing party in exceptional cases. Winning alone does not guarantee recovery.
13 Oct, 2026
