Houston Patent Infringement Claims Attorneys

Defending Texas Businesses Against Infringement Suits, Patent Trolls, & Invalidity Challenges

A patent infringement claim can land on your desk without warning – and unlike most legal disputes, you don't have to have done anything intentionally wrong to be liable. Under federal patent law, direct infringement is a strict liability offense. That means if your product or process uses a patented invention without authorization, it doesn't matter whether you knew the patent existed or not. You can still be sued.

Texas is one of the most active patent litigation venues in the country. The Eastern and Western Districts of Texas handle a disproportionate share of U.S. patent cases, and both courts impose strict deadlines. If you've received a demand letter, a cease-and-desist, or a lawsuit, move quickly to retain experienced patent litigation attorneys – not just to defend the claim, but to defend it correctly, aggressively, and within the required deadlines.

The attorneys at Hendershot Cowart P.C. represent Texas businesses in patent infringement claims in federal court – from the first demand letter through trial. Call (713) 783-3110 to discuss your situation with a member of our team.

On This Page:

• What Is Patent Infringement?
• Types of Patent Infringement Claims
• Defenses Against Patent Infringement Claims
• How We Defend Against Patent Infringement Claims
• Defending Against Patent Trolls
• Protect Your Business – Talk to a Houston Patent Infringement Attorney
• Frequently Asked Questions

Patent infringement occurs when someone makes, uses, sells, offers to sell, or imports a patented invention without the patent owner's authorization – during the period the patent is in force. Because patent law is exclusively federal, Texas state courts have no jurisdiction over patent infringement claims. All patent infringement cases are litigated in federal district courts.

The critical thing for businesses to understand: Direct patent infringement does not require intent. It is a strict liability claim, which means that intent or negligence isn’t considered. If your product or process falls within the scope of a patent's claimed invention, you can be held liable – even if you independently developed your technology and had no knowledge the patent existed.

Courts determine infringement by looking closely at the patent's written claims – the specific language within a patent application that defines the scope of the invention and what it covers. A product doesn't have to be an exact copy to infringe. Under the doctrine of equivalents, a court can find infringement even where a product doesn't literally match every element of a patent claim, but still performs substantially the same function, in substantially the same way, to achieve the same result.

If a patent holder wins, the court must award damages – at minimum, a royalty for the unauthorized use of the patent. In cases where infringement is found to be willful (the defendant knew about the patent and used it anyway), those damages can be multiplied up to three times. An injunction forcing you to stop selling or using a product is also a potential consequence of patent infringement.

There are two broad categories of patent infringement claims – direct infringement and indirect infringement – and the type of claim you’re accused of influences both the potential consequences of a claim and your defense options.

Direct Infringement

Direct infringement is the most straightforward claim. It applies when a party makes, uses, sells, offers to sell, or imports a patented invention in the United States without the patent owner's authorization.

There are two ways a patent owner can prove direct infringement. 

1. The first is literal infringement – every element of the accused product or process matches the patent's claims. 
2. The second is the doctrine of equivalents – even where a product doesn't match the patent's claims exactly, a court can still find infringement if the accused product performs substantially the same function, in substantially the same way, to achieve the same result.

For both theories, intent is irrelevant. You can be held liable for direct infringement without ever knowing the patent existed.

Indirect Infringement: Contributory Infringement and Inducement

Indirect infringement applies when a party doesn't directly use the patented invention itself, but either contributes to someone else's infringement or actively encourages it. Unlike direct infringement, indirect infringement requires knowledge – the accused party must have known the patent existed and known their conduct was contributing to infringement.

• Contributory infringement occurs when a party sells or supplies a component that is a material part of a patented invention – knowing it was specifically made or adapted for infringing use and that it has no significant other use. Knowledge is required, but specific intent to cause infringement is not.
• Inducement sets a higher bar. To establish inducement, a patent owner must show that the accused party actively encouraged a third party to infringe, knew the patent existed, and specifically intended for that infringement to occur. A good-faith belief that the patent is invalid is not a defense to an inducement claim.

One important limit: If no one is directly infringing, then another party cannot be accused of indirectly infringing. You can’t have one without the other. 

Receiving a patent infringement claim – whether a demand letter or a filed lawsuit – doesn't mean the patent owner wins. Patents can be challenged. Claims can be defeated. And in some cases, the right move is to go on offense before the patent holder sues you at all.

Defense strategies in patent cases generally fall into three categories.

1. Challenge the Patent's Validity

A patent is presumed valid under federal law – but that presumption can be overcome. If you can show by clear and convincing evidence that the patent should never have been granted, the infringement claim fails regardless of whether your product infringes.

The most common invalidity arguments are:

• Prior art. The invention was already known, publicly used, or described in an existing publication before the patent was filed. If the "invention" wasn't actually new, the patent shouldn't exist.
• Failure to meet patent requirements. A patent's written description must fully disclose the claimed invention and provide enough detail that someone skilled in the relevant field could actually reproduce it. If the patent falls short on either count, it may be invalid on those grounds alone.
• Unpatentable subject matter. Not everything is eligible for patent protection. Abstract ideas, for example, are not patentable. Courts have found that patents claiming nothing more than a well-known abstract concept dressed up in technical language are invalid.
• Inequitable conduct. If the patent applicant withheld material prior art from the patent office, or made misrepresentations during the application process, the patent may be unenforceable in its entirety – not just the claims at issue.

2. Assert Non-Infringement

The most common defense is also the most direct: Your product or process simply doesn't infringe the patent's claims. This requires a careful, element-by-element comparison of your product against what the patent actually covers – both under a literal reading of the claims and under the doctrine of equivalents.

3. Equitable and Other Defenses

Several additional defenses can limit or eliminate liability depending on the facts of your situation.

• Patent exhaustion prevents a patent holder from collecting twice. For example, if you purchased a component from a supplier who was authorized by the patent holder to sell it, you are generally protected from an infringement claim based on your use of that component. The patent holder already got their compensation when the authorized sale happened.
• Equitable estoppel can apply where a patent holder led you to believe it did not intend to enforce the patent – through explicit assurances or prolonged inaction – and you relied on that belief to your detriment.
• Prosecution history estoppel limits the patent owner's ability to use the doctrine of equivalents to recapture claim scope they voluntarily gave up during the application process. If they narrowed their claims to get the patent granted, they can't later argue those narrowed claims cover what they gave up.

Or, Take the Offensive with a Declaratory Judgment

You don't always have to wait to be sued. If a patent holder has accused you of infringement, sent a demand letter, or made licensing demands – even without filing suit – you may have grounds to file a declaratory judgment action first.

In a declaratory judgment action, you ask the court to declare that the patent is invalid, that you didn't infringe, or both. Filing first puts you in control of the venue and the timeline. It is a particularly effective tool against patent trolls, whose business model depends on extracting quick settlements before defendants have time to mount a serious challenge.

For businesses looking to proactively protect intellectual property – before a dispute arises – see our intellectual property and trade secret protection page.

The procedural stages of federal patent litigation each present a distinct opportunity to defeat or narrow a claim. Here is how we approach the defense against patent infringement litigation:

Attacking the Claim Early: Motion to Dismiss

The first question we ask is whether the case should proceed at all. If there is a basis to challenge the legal sufficiency of the complaint – including arguments that the patent covers nothing more than an abstract idea, or that the plaintiff has failed to identify the specific product or process allegedly infringed – we move to dismiss before the litigation gains momentum.

A successful motion to dismiss ends the case before discovery begins. That is the best possible outcome in terms of cost, time, and disruption to your business.

Challenging Infringement Contentions

Early in federal patent litigation, the patent owner must serve formal infringement contentions – a detailed, claim-by-claim explanation of exactly how your product or process allegedly infringes each element of each asserted patent claim. Texas federal courts, particularly the Eastern District, impose strict requirements on how specific those contentions must be.

If the plaintiff's infringement contentions are vague, overbroad, or fail to map their claims to your actual product, we challenge them. Contentions that don't meet the court's standards can be struck – and a case cannot proceed on stricken allegations.

Serving Invalidity Contentions

Once we receive the plaintiff's infringement contentions, we have a defined window to serve our invalidity contentions – our formal identification of the prior art and other grounds on which we contend the asserted patent claims are invalid.

This is one of the most consequential steps in patent infringement litigation. The prior art we identify here locks in our invalidity theories for the case. It also has strategic implications beyond the courtroom.

A defendant in a patent infringement case has the option to challenge the patent's validity not just in district court, but simultaneously – or alternatively – before the Patent Trial and Appeal Board, the federal body that reviews whether patents should have been granted in the first place. 

These parallel proceedings can be a powerful tool – but timing and coordination matter. If you raised a prior art reference in litigation, or could reasonably have raised it, you may be barred from relying on it again before a Patent Trial and Appeal Board proceeding. The reverse is also true – a successful board ruling that invalidates the patent can end the district court case entirely.

The strategic interplay between district court litigation and Patent Trial and Appeal Board proceedings is one of the more complex aspects of modern patent defense. We evaluate both paths at the outset and coordinate your positions across forums to protect your options.

Markman Hearing: Claim Construction

Before a patent case goes to trial, the judge holds a Markman hearing to define the key terms and language in the patent's claims. That interpretation – how broadly or narrowly the claims are read – directly determines what the patent actually covers and whether your product falls within it.

How the judge construes the claims can decide the entire case. We advocate aggressively at this stage for constructions that are most favorable to your defense, whether that means narrowing the scope of a claim so your product falls outside it or broadening a claim in a way that helps establish invalidity.

Motion for Summary Judgment

If the record developed through discovery supports it, we move for summary judgment – asking the court to rule in your favor as a matter of law, without a trial. A successful summary judgment motion ends the case and spares you the time, expense, and uncertainty of a jury trial.

Trial

If the case proceeds to trial, we are prepared. Patent trials are technically complex, document-intensive, and require attorneys who can translate sophisticated subject matter into a clear narrative for a judge or jury. Our goal at every prior stage is to have narrowed the issues, strengthened our position, and put you in the best possible posture if the case advances to trial.

Patent trolls – formally known as non-practicing entities or patent assertion entities – don't make products. They acquire patents, often broad or vaguely written ones, for the sole purpose of extracting settlement money from businesses that do. The model is straightforward: send demand letters to as many targets as possible, keep the settlement demand below the cost of litigation, and collect.

If you receive a demand letter from a patent troll, the goal isn't to win a lawsuit – it's to make fighting back more expensive than paying up. Recognizing that dynamic is the first step to responding effectively.

Why Texas Businesses Are Frequent Targets

Texas has historically been ground zero for patent troll litigation in the United States. The Eastern District of Texas – covering Marshall, Tyler, and Beaumont – handled a disproportionate share of all U.S. patent cases for more than a decade, driven by local court procedures that favored patent owners: fast trial schedules, early discovery requirements, and a reluctance to dismiss cases before trial. Patent trolls gravitated there precisely because speed and cost pressure forced defendants to settle rather than fight.

The Western District of Texas, particularly the Waco division, emerged as a second magnet in more recent years, drawing a significant influx of patent cases under similarly plaintiff-friendly conditions.

The landscape has shifted. In TC Heartland v. Kraft Foods – a dispute over where patent owners could drag corporate defendants to court – the Supreme Court ruled that patent infringement suits against corporations can only be filed where the defendant is incorporated or where it has committed acts of infringement and has a regular, established place of business. That ruling significantly curtailed the forum-shopping that had made East Texas a troll haven. 

But the problem hasn't gone away. Trolls have adapted – creating shell companies, maneuvering around venue rules, and shifting to new jurisdictions. And a proposed rule by the U.S. Patent and Trademark Office may make it harder and more expensive to challenge weak patents, removing one of the most efficient tools defendants had for killing bad patents before trial.

How We Respond

Patent trolls count on defendants who don't fight back. We do.

When a client faces a troll claim, we move quickly to evaluate the strength – or weakness – of the underlying patent, assess the specific allegations, and determine the most effective path forward. In many cases that means filing a motion to dismiss, challenging whether the patent covers anything more than an abstract or obvious idea. Where the patent has prior art vulnerabilities, we pursue invalidity aggressively.

Where appropriate, we file a declaratory judgment action to take control of the venue and the timeline before the troll does. 

Patent trolls’ business models focus on getting as much money as possible as soon as possible. As a firm that represents legitimate and successful businesses across Texas, we draw a hard line in the sand when clients face illegitimate claims and work aggressively to defend against recurrent claims and demands for what are, in effect, ransoms.

On occasion, we encounter situations in which the customers of our client, but not our actual client, are sued for patent infringement. In a typical case (such as those involving software licensing), your customers may request indemnification from the liability created by a patent troll's infringement claim. Our goal is to "beat the troll to the punch" by filing a declaratory judgment action.

In a declaratory judgment action, we ask the court to declare that the patent is invalid due to unpatentable subject matter, prior art, obviousness, and indefiniteness.

In these types of patent infringement cases, our Houston patent attorneys can, in effect, defend both you and your customers. If we are successful in obtaining a declaratory judgment, we will have the patent declared invalid before you are required to provide indemnity.

If you've received a demand letter, been named in a patent infringement lawsuit, or have reason to believe a claim is coming, the time to act is now. Patent litigation moves quickly, deadlines are strict, and the decisions made in the earliest stages of a case shape everything that follows.

The attorneys at Hendershot Cowart P.C. represent Texas businesses in federal patent infringement cases – from the first demand letter through trial. We evaluate the strength of claims made against you, identify your best defense options, and when the claim is meritless, we fight back.

If any of the following applies to your situation, contact us today:

• You've received a demand letter or cease-and-desist accusing your product or process of patent infringement
• You've been contacted by a company demanding a licensing fee you don't believe you owe
• You've been named in a federal patent infringement lawsuit
• Your customers are being targeted by a patent holder who may be looking to reach you next
• You want to challenge a patent's validity before a claim is filed against you

Call (713) 783-3110 or contact us online to schedule your initial consultation.

What is patent infringement?

Patent infringement occurs when someone makes, uses, sells, offers to sell, or imports a patented invention without the patent owner's authorization – during the period the patent is in force. Courts look closely at the specific claims written into the patent to determine whether infringement occurred.

What is the doctrine of equivalents?

A patent's written claims define exactly what the invention covers. But a product that doesn't match those claims word for word can still lead to a patent infringement claim due to the doctrine of equivalents. Under this doctrine, a court can find infringement even where a product or process doesn't literally match every element of a patent claim – if it performs substantially the same function, in substantially the same way, to achieve the same result. The analysis is done element by element, not as a broad comparison of the two products overall.

There are limits. If a patent applicant narrowed the scope of their claims during the application process – to distinguish the invention from existing technology, for example – they may be barred from later using the doctrine of equivalents to recapture the ground they gave up. This is known as prosecution history estoppel.

What is willful infringement?

Willful infringement is infringement the defendant knew about and proceeded with anyway. If a patent owner can show you were aware of their patent and continued to make, use, or sell the infringing product regardless, a court can find the infringement was willful.

The practical consequence is significant: a finding of willful infringement gives the court discretion to award enhanced damages – up to three times the baseline damages award. That multiplier is why patent holders frequently argue willful infringement even in cases where the underlying infringement claim is straightforward.

What are infringement contentions and invalidity contentions? 

Infringement contentions are the patent owner's formal, claim-by-claim explanation of exactly how your product or process allegedly infringes each element of each asserted patent claim. Invalidity contentions are the defense's formal response identifying the prior art and other grounds on which the asserted patent claims are invalid. Texas federal courts – particularly the Eastern District – impose strict deadlines on both. Miss those windows, and your ability to raise certain arguments at trial can be lost entirely.

What is a patent troll, and how do I respond to one? 

Patent trolls – also called non-practicing entities – are companies that acquire patents primarily to sue others for financial settlements, rather than to make or sell anything. They often send broad demand letters targeting many businesses at once. If you receive a demand letter or lawsuit from a patent troll, an early and aggressive response – including challenging the validity of the patent and, where appropriate, filing a declaratory judgment action to control the venue and timeline – is frequently more effective than paying a settlement that signals you're worth targeting again.

What should I do if I receive a patent infringement claim? 

Do not ignore it. Patent infringement claims carry real exposure – including injunctions that can force you to stop selling a product, damages of at least a reasonable royalty, and potentially much more if infringement is found to be willful. Deadlines in federal patent litigation are strict and consequences for missing them are severe. Contact an attorney as soon as possible to evaluate the claim, assess your defense options, and respond before your options narrow.

Facing a patent infringement claim in Texas? Our Houston attorneys defend businesses against infringement suits, patent trolls, and invalidity challenges. Call (713) 783-3110 or contact us online to speak to a member of our team.