Patent Law News + Insights

Patent Infringement: How It's Proven, and How This Should Influence Your Patent Filings

January 4, 2019

As a patent owner, you have the legal right to exclude others from making, using, selling, or offering to sell the invention. Put another way, your competitors cannot make, use, sell, or offer the invention described in your patent’s claims without your permission.

Accordingly, if you discover that a competitor’s product is infringing your patent, you can claim monetary damages in federal court, and in some cases you can even get an injunction to stop the infringing behavior.

But what does it take, in a legal sense, to prove that patent infringement has occurred — and what steps can you take in the process of getting your patent to ensure your patent is enforceable against infringers?

What constitutes patent infringement?

Under U.S. law, there are a few different ways patent infringement can happen:

  • Direct infringement: A single entity’s product or service meets all the limitations of at least one independent claim in your patent. The party in question doesn’t need to know that your patent exists in order to be held liable.
  • Indirect infringement: One entity causes or assists another entity to create a product or provide a service that meets all the limitations of at least one independent claim in your patent. There are two types:
    • Induced infringement: The infringer knows about the patent, and knowingly causes the other party to directly infringe the patent.
    • Contributory infringement: The infringer knowingly provides a component or product that helps the other party directly infringe the patent, and the component or product doesn’t have any substantial non-infringing use.

To recover monetary damages from the infringer, you’ll also have to prove the value of a reasonable royalty for the invention.

patent-infringement

How do I prove patent infringement?

To enforce a patent against a competitor, you’ll need to show three things:

  1. That you own a valid patent
  2. That the alleged infringer has engaged in an act of infringement
  3. That the infringing product or process incorporates all the distinguishing features of at least one independent claim

Let’s break each step down.

Proving ownership of a valid patent

Ownership. First, you’ll have to prove that you own the patent — which is usually easily shown through a written assignment. But in some cases, proving ownership can be non-trivial. For example, ownership can become an issue if a written assignment was never properly executed by the inventors, or if one of the inventors disputes the assignment. This is why it’s imperative to always properly document ownership at the outset of the patent process.

Validity. Issued U.S. patents are presumed to be valid and enforceable by law. But if you enforce a patent, the defendant (the infringer) will be highly motivated to challenge the patent. In fact, take it as a rule of thumb that every defendant in every patent infringement lawsuit will find some reason to challenge validity.  So you need to be prepared to defend the validity of your patent, against even seemingly far-fetched arguments that might be advanced by the infringer.

Some common reasons why a patent may be invalidated (or held unenforceable):

  • Claims are obvious or anticipated in view of prior art
  • Subject matter is not patent-eligible (e.g., due to recent changes in the law)
  • Patent holder included incorrect or misleading info in the patent application, or intentionally withheld material information during prosecution
  • Patent specification does not provide sufficient written description or enabling detail to support the claims
  • Claims are ambiguous to the extent that they are not understandable (Nautilus v. Biosig changed the standard for determining whether claims are “definite” under Section 112)

Proving an act of infringement

Someone has engaged in an act of infringement if they have made, used, sold, or offered to sell the invention claimed in your patent without your permission. Also, keep in mind that the act of infringement generally has to occur in the United States if you’re enforcing a U.S. patent. There are some limited circumstances where an infringer’s activities outside the U.S. may be considered relevant, but those should be considered narrow exceptions to the general rule.

The key here is proving the identity of the person who committed the infringing act. In many industries, many different entities collaborate to produce an end product or service, which creates an opportunity for each individual entity to say, I didn’t do it.

So you’ll need definitive proof of what legal entity is selling the infringing product or providing infringing service. You might be able to use sales data, SEC filings, advertisements, product catalogues, information from the infringer’s website (e.g., product demos), or other types of information to prove who committed the act of infringement.

Proving that the product or process infringes your patent

It’s not enough for you to broadly state that patent infringement has occurred, and point generally to the infringing product or service. In fact, the federal pleading standards for patent infringement (i.e., the minimum “proof” that you need to show at the very beginning of a patent infringement lawsuit) have become even more rigorous over the last decade, requiring even more specificity to initiate patent litigation in federal court.   

To meet these standards, you’ll need to do a detailed claims analysis that clearly: (1) explains the contents of your patent claims, and (2) compares the claims to the infringing elements of the competitor’s product.

This is usually shown in the form of a “claim chart,” which is basically a big table with two columns. Here’s an example:

Claim 1

Competitor’s Time Machine

A time-travel machine comprising:

Comparable element #1

a flux capacitor; and

Comparable element #2

a keypad for entering a destination time.

Comparable element #3


You have to show that the infringer’s product (or process) has each and every component (or step) that is listed in at least one of your
independent claims. This is a critical point. If their product or process doesn’t include components that are described only in the specification or the dependent claims, that’s okay.

This is why, in general, we help our clients obtain patents with broad independent claims with as few elements as possible: It’s easier to show infringement.

Keep in mind that the claims will be interpreted in light of the specification. The process of claim interpretation is often the most contentious part of patent litigation. Don’t assume that your claims mean something very broad or narrow; consult the patent’s specification and prosecution history to understand how each claim term was used throughout the patent. In particular, look for explicit and implicit definitions of key terms.

What if my patent is pending?

If you have a patent pending, you have a very limited ability to hold the infringer liable: only after your patent has issued, and only if the application was published with substantially the same claims that are eventually issued.

But just being able to use the label “patent pending” usually serves as a good deterrent to competitors. I’ve heard several anecdotes and seen specific cases where people will avoid copying a product based simply on the fact that a patent application was filed — regardless of how strong the patent is.

How to draft a high-quality patent that can be enforced

To be able to enforce your patent, you first need to draft a patent containing claims that make it relatively easy for you to show the three elements outlined above.

Draft a patent that will withstand close scrutiny

The most common way for a patent’s claims to be invalidated is through unexpected prior art.

For this reason, a thorough prior art search or prior art analysis is always valuable. You should also disclose all relevant prior art to the patent office so that it’s evaluated during the examination process. An infringer will have a much harder time invalidating your patent based on prior art that was considered by the patent examiner. (By contrast, the infringer will always try to make a case that the patent office would not have issued the patent if the examiner had just seen this one reference, even if the reference isn’t all that relevant.)

Ensure acts of infringement are easily detected

Before you can pursue litigation against a competitor, you have to detect an act of infringement on their part. In other words, your competitor needs to do something that you can detect using public information.

Accordingly, you should seek patent protection for, and craft your claims to cover, inventions where you can easily detect infringement using public information.

If it won’t be easy to detect infringement (for example, if your invention relies on a cloud-deployed process, or an in-house fabrication process), you may want to consider a different form of IP protection instead, such as trade secret protection.

Write well-constructed claims with diverse scope

Your patent should contain well-constructed claims that clearly describe what your patent covers. For this reason, it’s important to engage a patent attorney with the right technical expertise to understand the technology you’re developing.

In addition, your patent should contain diverse scope of broad independent claims and narrower dependent claims. Broad claims reduce the likelihood that a savvy competitor will design around your claims, while narrow dependent claims reduce the likelihood that prior art will invalidate all your claims.

The goal is to find at least one claim that is broad enough to be infringed, while narrow enough to withstand prior art challenges. You won’t always know in advance (when your drafting your patent application and negotiating with the patent office) what the right balance will be, which is why it’s best to pursue a mixture of broad and narrow claims — to leave yourself as many options as possible in the litigation context.

Want to draft a high-quality, enforceable patent?

IP, and particularly a robust patent portfolio, is one of the most valuable assets for a high-tech startup. For this reason, it’s important to invest in a strong strategy — and that includes engaging a qualified patent attorney to help you with the patent process.

The team at Henry Patent Law Firm has assisted dozens of companies from diverse tech fields. Contact us now to find out if we’re a good fit for your needs!

contact us hpl

POSTED IN: All Posts, Patent Prosecution, Patents

Michael Henry

Michael Henry is a principal and the founding member of Henry Patent Law Firm PLLC. Michael specializes in creating comprehensive, growth-oriented IP strategies for early-stage companies who are developing emerging technologies.

Learn More