(Updated September 2025 for clarity and accuracy.)
Patent infringement can threaten your business, drain your resources, and derail your hard work. If someone is using your patented invention without permission, or if you’re being accused of infringing on someone else’s patent, it’s important to understand your rights and what steps to take next.
This guide explains what patent infringement is, how it’s determined in court, what legal remedies are available, and when to talk to an attorney. Whether you’re protecting your own invention or responding to a potential claim, it’s worth taking the time to understand how patent law works.
What Is Patent Infringement?
Patent infringement occurs when someone makes, uses, sells, or offers to sell a patented invention without the patent holder’s permission. This applies regardless of whether the infringement was intentional or not.
Patents are granted by the United States Patent and Trademark Office (USPTO) and give inventors exclusive rights to their inventions for a limited period of time. If those rights are violated, the patent holder can pursue legal action to enforce them.
Types of Patent Infringement
Patent infringement can take several forms, including:
- Direct Infringement: Someone makes or sells your patented invention without permission.
- Indirect Infringement: A party helps or encourages someone else to infringe a patent.
- Contributory Infringement: A party provides a component that has no significant non-infringing use, contributing to infringement.
- Literal Infringement: The infringing product or process matches every element of at least one claim in the patent.
These types matter because they guide how a court determines whether your patent has been violated, and what legal remedies might apply.
How Is Patent Infringement Determined?
Patent law is governed by federal statutes, so infringement claims are handled in federal district court.
To determine whether infringement has occurred, the court compares the language of your patent’s claims to the accused product or process. Patent claims define the specific legal boundaries of your invention — that is, the features or steps that others aren’t allowed to copy. If the claims are fully met by the alleged infringer, even unintentionally, infringement may be found.
If you disagree with the district court’s decision, you can appeal to the Court of Appeals for the Federal Circuit, and in rare cases, to the U.S. Supreme Court.
How Long Do You Have to File a Lawsuit?
Under U.S. law, a patent holder has six years from the date of the infringement to file a lawsuit. After that, the claim may be time-barred, meaning it can’t proceed in court. If you suspect your patent is being infringed, it’s important not to delay.
What Are the Penalties for Patent Infringement?
If the court finds in your favor as the patent holder, you may be entitled to several powerful legal remedies designed to stop the infringement and compensate you for your losses:
- Injunctions: A court order requiring the infringing party to stop making, using, or selling the infringing product. This can be especially important if the product is actively harming your market share or reputation.
- Monetary Damages: Courts may award compensation based on either your lost profits (what you would have earned if the infringement hadn’t occurred) or reasonable royalties (what a licensee would have paid for legal use of your invention).
- Enhanced Damages: In cases of willful infringement, the court can award up to three times the actual damages as a punitive measure. These cases often involve a defendant who knew about your patent but chose to proceed anyway.
- Legal Costs: In certain situations, such as when the infringement is especially egregious, the court may order the losing party to pay your attorney’s fees and litigation expenses.
These remedies can be substantial, but only if they’re properly argued for in court.
👉 That’s why working with an experienced patent attorney is essential. A lawyer can help you:
- Gather the right evidence to prove infringement and damages
- Argue for the strongest remedies available under the law
- Maximize the likelihood of a favorable outcome
- Negotiate from a position of strength if settlement is on the table
Without skilled representation, you may leave money on the table — or worse, lose your case entirely due to a technical misstep.
How to Avoid Accidentally Infringing on a Patent
While this post focuses primarily on enforcing your patent rights, it’s also important to avoid infringing on others’ patents, especially if you’re developing or launching a new product.
Simple mistakes or assumptions can lead to costly lawsuits. The best way to protect yourself is to conduct research, evaluate risks early, and talk to a patent attorney before moving forward.
Defenses Against a Patent Infringement Claim
If you should find yourself on the receiving end of a patent infringement claim, don’t panic — but don’t ignore it either. These are serious matters with real legal consequences.
Common defenses to patent infringement include:
Noninfringement: Arguing that your product or process doesn’t violate the specific claims of the patent.
Invalidity: Challenging the validity of the patent itself, which is one of the most common defenses. A patent may be deemed invalid if:
It lacks novelty (someone else disclosed the invention before you filed)
It is obvious in light of prior art (a combination of earlier inventions makes yours an obvious next step)
It fails to meet statutory requirements, such as utility or adequate written description
The patent was obtained through fraud on the USPTO (for example, by knowingly submitting false or misleading information during prosecution)
Unenforceability: Asserting that the patent, even if valid, cannot be enforced due to inequitable conduct or anti-competitive behavior.
Keep in mind: the burden of proof is on the patent holder, but that doesn’t mean you should navigate this alone. A qualified attorney can help you assess your options, avoid costly missteps, and respond strategically.
Get Help from a Patent Infringement Attorney
Whether you’re enforcing your rights or responding to an infringement claim, patent disputes are complex. At Larson & Larson, we’ve been helping inventors and businesses protect their intellectual property for more than 30 years.
We can help you evaluate whether infringement has occurred, determine if your patent is enforceable, and take legal action or respond to a claim strategically and efficiently.
📞 Call us today at (727) 546-0660 to learn more.
Published by Larson & Larson, a Florida-based intellectual property law firm serving clients since 1987.
