Patent Litigation - A Primer for Businesses

Innovation is a cornerstone in today’s economy and the importance of protecting intellectual property is more critical than ever. In order for businesses to protect their innovations, they must acquire patents and enforce them. The ultimate patent enforcement tool is patent litigation. Whether your company is defending against an alleged infringement, evaluating a competitor’s technology, or proactively enforcing your patent rights, understanding the nature of patent cases and how they proceed can help protect your business, reduce costs, and better prepare you for success.

This article serves as a primer for business owners, executives, and entrepreneurs seeking an understanding of patent litigation.

Patent Lawsuits and Disputes

Patent litigation arises when a patent owner files a lawsuit alleging that another party has infringed one or more patent claims, which define the patented invention. The claims are the critical component of a patent and the core of a patent dispute. The analysis at the core of any patent litigation is the determination of what the patent claims mean and a determination of whether the alleged infringer engages in each and every limitation in the asserted patent claim.

Infringement Analysis Example

To illustrate this, consider a basic example involving a common tool: a handsaw. Suppose a company holds a patent with the following independent claim:

Claim 1: A handsaw comprising:
(a) a handle;
(b) a detachable blade removably coupled to the handle; and
(c) a locking mechanism configured to secure the blade to the handle during use.

This claim defines a handsaw invention that includes three required features: a handle, a blade that can be detached and reattached, and a locking mechanism that holds the blade in place.

Potential Infringement Scenario

Now, imagine a competitor begins selling a handsaw with the following features: a handle; an extendable blade that slides into the handle when not in use; and a locking mechanism that secures the blade in its extended position.

While the competitor's saw does not have a detachable blade per se, it does have a blade that moves relative to the handle and can be locked in place. This raises the central question in patent litigation: Does the competitor's handsaw include each and every limitation of the patent claim.

Infringement Analysis

The analysis would begin by comparing each element of the patent claim to the accused product—a process known as “element-by-element” or “all-elements” analysis:

• The competitor’s saw includes a handle—check.

• It includes a blade—check.

• It includes a locking mechanism—check.

• But is the blade detachable?

The analysis will turn on whether the extendable blade in the competitor’s saw can be considered a detachable blade. If the blade is only extendable (i.e., it slides in and out but cannot be completely removed), then a court would likely find that this feature is not literally the same as a "detachable" blade. Therefore, there may be no literal infringement. However, the patent owner might argue that there is infringement under the doctrine of equivalents.

What Is the Doctrine of Equivalents?

The doctrine of equivalents allows a court to find infringement even when an accused product does not literally meet every element of a claim—so long as the differences are insubstantial. Under this doctrine, an element in the accused product is considered equivalent to a claimed element if it performs substantially the same function, in substantially the same way, to achieve substantially the same result.

Returning to our example: the patent owner may argue that although the competitor’s blade is extendable rather than fully detachable, it still allows the user to store or adjust the blade and secures it during use—thus performing the same function, in a similar way, for the same result. If the court agrees, it may find infringement under the doctrine of equivalents, despite the literal difference in blade structure. The outcome would depend on how the court interprets the scope of the term “detachable” in the context of the claim and the patent’s prosecution history at the patent and trademark office. Here, an extendable blade would likely not be considered detachable because it does not have the same function or result.

If the court finds no infringement—either literally or under the doctrine of equivalents—the competitor’s product does not infringe, and the patent infringement complaint would likely be dismissed. But if the court finds that the extendable blade is equivalent to a detachable blade, the patent owner may prevail, potentially recovering monetary damages or even securing an injunction.

Most patent disputes do not involve such a simple device. These disputes often involve advanced technologies in electrical engineering, mechanical engineering, life sciences, and computer science. Whether in pharmaceuticals (e.g., generic versions of branded drugs), software, or medical devices, litigation can center around products and processes worth millions—or even billions—of dollars.

Direct or Indirect Infringement

In patent litigation, infringement can be either direct or indirect, and understanding the distinction is essential for assessing liability. Direct infringement occurs when a party, without authorization, makes, uses, sells, offers to sell, or imports a product or process that is covered by one or more patent claims. This type of infringement does not require proof of intent or knowledge—it is a strict liability offense under patent law. In contrast, indirect infringement involves conduct that facilitates or contributes to another party’s infringement. There are two main types: induced infringement, where a party actively encourages or instructs someone else to infringe (e.g., through manuals, advertisements, or technical support), and contributory infringement, where a party supplies a component that has no substantial non-infringing use and is specifically made for use in a patented invention. Indirect infringement generally requires proof of knowledge of the patent and the underlying infringement.

Identifying and Addressing Patent Infringement Claims

When preparing to initiate a patent infringement complaint, patent owners must begin with a rigorous assessment of their patent claims. This includes analyzing the claims for clarity, scope, and enforceability, and conducting a thorough investigation of potential defenses such as invalidity, relevant prior art, lack of enablement, insufficient written description, or inequitable conduct before the patent and trademark office. Technical analysis, often involving expert consultants in mechanical engineering, electrical engineering, or computer science, is highly important because the technology captured in the patent and the allegedly infringing device must be clearly understood to make a proper infringement evaluation. Only those claims that are well-supported and likely to survive scrutiny from the district court should be asserted. Pursuing flimsy or questionable claims may lead to high litigation costs with little chance of success.

From the defendant’s perspective, it is important to understand that not all patent infringement claims are equally strong. Some patent lawsuits are speculative or overreaching, and in those cases, early procedural tools such as motions to dismiss or summary judgment may allow for a swift and cost-effective resolution. On the other hand, some infringement allegations are well-founded and may expose the accused infringer to significant liability. In such instances, businesses should consider halting potentially infringing activity to mitigate the risk of further monetary damages and a finding of willful infringement, which can result in enhanced damages. The asserted patent claims should be evaluated for their scope and potential invalidity. Vague, complex, or difficult to interpret claims may be challenged as lacking definiteness and may be invalid or difficult to enforce. The claims may also be invalid on other bases, such as being anticipated or rendered obvious by relevant prior art.

Invalidity Challenges

There are multiple ways to challenge the validity of a patent, and these can be pursued either in federal district court as part of the infringement litigation or separately before the Patent Trial and Appeal Board (PTAB) at the United States Patent and Trademark Office. In district court, defendants may raise invalidity as an affirmative defense and seek to invalidate the asserted patent claims through dispositive motions or at trial. The most common grounds for patent invalidity include:

Anticipation (35 U.S.C. § 102): A claim is invalid if all its elements are disclosed in a single piece of prior art—such as a patent, printed publication, or public use—before the effective filing date. Such a claim lacks novelty.

Obviousness (35 U.S.C. § 103): Even if a claim is not identically disclosed in one reference, it may still be invalid if the combination of multiple prior art references would have made the invention obvious to a person of ordinary skill in the art.

Lack of Written Description (35 U.S.C. § 112): The patent specification must clearly describe the invention as claimed, demonstrating that the inventor possessed the claimed subject matter at the time of filing.

Lack of Enablement (35 U.S.C. § 112): The specification must enable a person skilled in the art to make and use the full scope of the claimed invention without undue experimentation.

Indefiniteness (35 U.S.C. § 112): A claim is invalid if it fails to particularly point out and distinctly claim the invention, rendering the scope of the patent unclear.

Inequitable Conduct: If the patent applicant intentionally withheld material prior art or made misleading statements during prosecution, the patent may be rendered unenforceable due to misconduct before the patent and trademark office.

Fraud or Derivation: In rare cases, patents may be challenged on the basis that the patentee was not the true inventor or that fraud occurred during the prosecution process.

Administrative Challenges Before the PTAB

In parallel or as an alternative to litigation in district court, accused infringers can pursue administrative challenges before the Patent Trial and Appeal Board, a specialized tribunal within the USPTO. The most commonly used proceeding is inter partes review (IPR), which allows third parties to challenge the validity of issued patents based on prior art consisting of patents or printed publications.

IPRs have become a powerful tool in IP litigation, particularly in industries like life sciences, computer science, and consumer products, where invalidity arguments often depend on dense technical disclosures. Compared to district court litigation, PTAB proceedings are relatively fast (typically completed within 12–18 months) and are decided by a three-judge panel with technical and legal expertise. Other PTAB proceedings include post-grant review (PGR) and covered business method (CBM) review, though their availability is limited by statutory criteria and filing windows.

An IPR petition can be a strategic way to stay or pause the district court proceedings, narrow the scope of litigation, or force the patent owner into settlement discussions. However, success at the PTAB requires careful planning, high-quality prior art, and persuasive expert declarations.

Initiating Patent Litigation

Before initiating a patent infringement complaint, a thorough evaluation of the asserted patent claims should be conducted to ensure they are strong, enforceable, and likely to withstand legal scrutiny. This analysis should be paired with an economic assessment of the potential litigation, including the cost of enforcement, the likelihood of success, and the anticipated value of any monetary damages or injunctive relief. In many cases, it may be prudent to consider alternative dispute resolution methods—such as mediation or arbitration—as potentially less costly and more expedient paths to resolution.

Once a decision is made to proceed with litigation, it is essential to determine the proper jurisdiction and venue. The complaint must be filed in a federal district court that has personal jurisdiction over the defendant and meets the statutory venue requirements under the patent law framework. Procedural considerations such as service of process, especially in cases involving foreign defendants or multiple parties, must be carefully planned. When suing multiple defendants, strategic decisions should be made regarding whom to name in the case. It may not be possible to sue all defendants in a single jurisdiction due to a lack of personal jurisdiction over some defendants in the chosen venue. Plaintiffs often focus on those who are most culpable, are in the best position to pay damages, or play a central role in the alleged infringement.

Additionally, patent owners must be aware of statutory limitations on damage recovery—most notably, the six-year limitation under 35 U.S.C. § 286 and ensure the complaint is filed in a timely manner. Given that patent litigation can be prohibitively expensive, with average costs ranging from $3.5 million to $5 million through trial, managing patent litigation costs is a critical component of any enforcement strategy. This requires detailed budgeting, clear goals, and disciplined oversight to ensure that the litigation remains aligned with the business’s objectives and financial resources.

Discovery and Pre-Trial Motions

Discovery is a critical phase of any patent trial and often spans several months to years, depending on the complexity of the case and the number of parties involved. During discovery, both sides are required to exchange relevant information, including technical documents, design schematics, source code, financial records, and other materials that may support or refute the claims and defenses in the case. This process also involves the deposition of key witnesses, such as inventors, engineers, marketing personnel, and damages experts, whose testimony may be used at trial.

As the trial date approaches, parties typically file pre-trial motions to address issues that could affect the scope and structure of the proceedings. These motions, usually filed within a month or two of trial, can significantly narrow or shape the litigation. Common pre-trial motions include motions for summary judgment (which seek to dispose of some or all claims before trial), motions to exclude expert testimony (often based on Daubert standards), and motions to strike pleadings or evidence that are procedurally or substantively deficient. Effective use of discovery and pre-trial motion practice is essential to building a persuasive case, managing litigation costs, and increasing the likelihood of a favorable outcome.

Markman Hearing

A Markman hearing, also known as a claim construction hearing, is a pre-trial proceeding in patent litigation where the court interprets the meaning and scope of disputed patent claims. Because a patent’s enforceable rights are defined by its claims, determining what the claims mean is a critical step in assessing infringement and validity. The hearing is named after the Supreme Court case Markman v. Westview Instruments, Inc., which held that claim construction is a matter of law to be decided by a judge, not a jury. During the hearing, both parties present arguments, often supported by expert testimony and intrinsic evidence such as the patent specification and prosecution history, regarding how specific claim terms should be interpreted. The judge’s ruling can significantly influence the outcome of the case, and it often shapes later decisions on summary judgment, infringement, and invalidity. Markman hearings are a cornerstone of modern patent trial practice.

Trial Stage

A patent infringement trial is typically held before a jury, which is tasked with resolving the key factual disputes in the case, including whether infringement occurred and, if so, the amount of monetary damages owed. During trial, the plaintiff’s attorneys will present the patent to the jury, explain how the invention works, and introduce testimony from fact and expert witnesses to support their infringement and damages claims. The defendant has the opportunity to cross-examine these witnesses and present its own case, often focusing on arguments that the patent claims are invalid or that the accused products or methods do not actually infringe. Successfully navigating the trial stage requires a combination of clear, persuasive communication and strategic litigation planning, particularly when explaining complex technical concepts to a lay jury.

Post-Trial Motions and Appeals

After a patent trial concludes and a verdict is rendered, the litigation often continues with post-trial motions. These motions are typically filed to address issues arising from the trial, such as requests to overturn the jury’s verdict, motions for a new trial, or motions to amend the judgment. If a party believes that the trial court made a legal error, the next step may be to file an appeal with the Federal Circuit, which has exclusive jurisdiction over patent law appeals. In rare but significant cases, parties may seek review by the Supreme Court. While these proceedings can be time-consuming and costly, they may also offer a critical opportunity to reverse or modify an unfavorable verdict and can be essential to protecting valuable patent rights.

Conclusion

Patent litigation is a complex and high-stakes endeavor that can significantly impact a company’s business strategy, market position, and financial health. Whether asserting patent rights or defending against infringement claims, a clear understanding of the legal framework, procedural stages, and strategic considerations is essential. By approaching litigation with thorough preparation, informed counsel, and a disciplined focus on both legal and commercial objectives, businesses can better protect their innovations, mitigate risk, and position themselves for favorable outcomes in today’s competitive landscape.  If you have developing patent dispute or other patent matter, please contact our office for a free consultation.

© 2025 Sierra IP Law, PC. The information provided herein does not constitute legal advice, but merely conveys general information that may be beneficial to the public, and should not be viewed as a substitute for legal consultation in a particular case.