When preparing your patent application, you might want to save money by conducting your own prior art search.

Or maybe you already have an issued patent and need to find out if someone has infringed it — or vice versa.

If you work at a tech company, you’ll likely encounter many situations where you need to make decisions regarding your company’s intellectual property and legal strategy. In these cases, being able to read and understand a patent can be an invaluable skill.

Patents are complex legal documents, so be sure to get a patent attorney involved if you want to do an in-depth analysis of the legal issues and risks at stake. But having a basic understanding of how patents work can help you to make quicker decisions and communicate more effectively with your patent counsel.

With that in mind, we’ve put together this quick guide to walk you through the anatomy of a typical U.S. utility patent.


Broadly, the typical patent consists of four main parts:

  1. Front page(s)
  2. Drawings
  3. Specification
    1. A background section
    2. A list of drawings
    3. A detailed description 
  4. Claims

The specification may also include the following other sections, though these are generally not required:

  • A summary section
  • A cross-reference to related applications
  • A statement of government support


However, keep in mind that there are several important things that the patent will not tell you, such as:

  1. Have the maintenance fees been paid?
  2. Has the patent expired? 
  3. Who is the current owner of the patent?
  4. Has the patent been invalidated, enforced, licensed, or sold?
  5. Have any further applications (like continuations or divisionals) been filed for this subject matter after this patent was granted?

With that overview in mind, let’s take a closer look at each section of a patent application, using an expired patent as an example for reference.


The Title, Abstract, and Drawings provided on the front page simply summarize the technology described in the patent and the general field of the patent disclosure. They are not the primary sources for determining what the patent actually covers (that’s laid out in the Claims at the end of the patent).


This is fairly self-explanatory — it’s the full title of the patent. The applicant usually chooses the title, but sometimes the patent office suggests changes during the examination process. 


Anyone who has contributed to conceiving the invention recited in at least one claim in the patent will be listed here, along with their city of residence.

Under U.S. law, patent rights are owned by the inventor(s) by default (i.e., in the absence of an agreement otherwise). So if you want to know who owns a patent, you can start with the inventors. But in the vast majority of cases, the inventors assign their rights to their employer or another business entity. 


This shows whether the patent was owned by a person or business entity other than the inventors at the time the patent was issued by the U.S. patent office.

But the patent may have been assigned or transferred since it was initially issued. To obtain the most up-to-date public information on the patent’s assignee, check the USPTO assignment database.


This is generally the default “effective filing date” for all claims in the patent — that is, the watershed date for determining what prior art can be used to invalidate the patent.


Sometimes a patent application “claims priority” to one or more earlier patent applications. The earlier patent application is generally referred to as the “priority application.”

Examples of potential “priority applications” include:

  • A provisional application
  • A foreign application
  • A PCT application
  • An earlier non-provisional application filed in the United States

Consequently, this section tells you the earlier dates that could be considered the “effective filing date” of the patent.

However, a patent will sometimes list a priority application that does not sufficiently describe the claimed invention. Claims that are not sufficiently described in a priority application do notbenefit from the priority application’s effective filing date. In these cases, the claims’ effective filing date would default to the “filing date” listed above.


This is a list of references that were considered by the patent office during the examination process. In other words, the examiner concluded that the patent’s claims were patentable over the prior art described in these references.

It will be very hard for a third party to use any of the references listed in this section to challenge the validity of the patent (for example, in an IPR proceeding), because it’s presumed that the patent office did its job correctly when initially examining the patent.

Consequently, as a patent owner, you want the closest prior art to be cited here so that you have the strongest presumption of validity in your favor.


This, too, is fairly self-explanatory — this is a brief summary of the invention in broad terms. The Abstract has to be 150 words or less, and it’s often drafted based on the claims that were initially filed in the application that led to the issued patent. 


The examiner will choose one representative drawing of your invention to include at the bottom of the front page. This often defaults to Figure 1.


With a few rare exceptions (for example, if the invention relates to a chemical compound or composition), most U.S. patents will include drawings.

Located immediately following the front page, the drawings help the reader to understand the invention. The drawings must show all claimed elements.

Drawings labeled “Prior Art”, such as Figures 1 and 2 in the example above, are not part of the patented invention. But they’re used to document any prior processes that existed before the invention was made.


Simply, the specification refers to the written part of the patent, not including the front page and the drawings. (Under U.S. law, the claims are technically part of the specification, but we treat them separately in this post because of their importance.)

The specification provides the most relevant context for interpreting the claims in the final section of the patent. For example, if the specification includes a definition for a term in the claims, then the claims will be interpreted using that definition.

Basically, all terminology in the claims will be interpreted in a way that is consistent with the terminology used in the specification. As patent lawyers like to say, “the patentee is their own lexicographer.”


The background briefly describes the general context of the invention. Everything in the background section can potentially be considered “admitted prior art” by the examiner, so the background section often says very little about the actual invention that’s being patented. 


The detailed description (together with the summary section, in some cases) are the main technical disclosure of the patent.

This section lays out the enabling disclosure of invention in writing — that is, it describes the invention in terms that would allow a person with ordinary skill in the field to be able to make or use the invention. The detailed description also describes the best mode for making and using the inventions.

Each figure and each reference number from the drawings should be called out and named here. The description may also include different embodiments of the invention.

Before we move on to the claims, keep in mind that the entire issued patent can be used as prior art against later-filed patent applications. Basically, if you’re looking at a patent to determine whether your own invention is patentable, the most relevant section for your analysis will typically be the patent’s detailed description.


The most important part of the document, the claims set forth and define the patent’s scope of exclusive rights. In other words, they describe what the patent does or does not cover. Each claim element should be shown in the drawings and described in the detailed description.

There are two different ways to categorize the types of claims you’ll find in a typical patent.


Most patents will include both system and method claims.

System claims generally describe tangible things. It can either be phrased using a broad category (e.g., “system,” “device,” or “apparatus”), or with a narrower term of art (e.g., “drill bit” or “keyboard”). A system claim might use functional language to describe certain elements, but the “elements” of a system claim are components of the system.

Method claims generally describe a process or series of steps. Method claims often refer to a thing that performs the process, but the “elements” of the method claim are the operations themselves. Usually the steps or operations are styled as gerund phrases (e.g., “pressurizing a chamber” or “sending a transmission”).

Alternatively, software-implemented inventions may utilize computer-readable medium (CRM)claims. These are usually thought of as an object (like a system claim) that is programmed to perform a series of steps (like a method claim) — making them a hybrid type of claim.


 Independent claimsDependent claims
ScopeBroadest claims in the patentFurther narrows the scope of an earlier, independent claim
Identifying featuresTypically start with the word “A” (like “A system …” or “A method …”).Don’t refer back to another claim.Always explicitly refer to another claim (like “the method of claim 3…”).
Should it be used to determine if a product or process infringes the patent?Yes.No. At least not primarily.
Why?If the product infringes even one of the independent claims, then the product infringes the patent.If the product does NOT infringe any of the independent claims, the product doesn’t infringe the patent.Dependent claims are always narrower than the claim that they depend from, meaning that a product CANNOT infringe a dependent claim unless the product also infringes the claim from which it depends.But dependent claims are useful for interpreting the independent claims, so don’t ignore them. 

Even though dependent claims can’t be used to determine if a competing product or process has infringed the patent, they’re still important because they provide a backup position for enforcing the patent. For example, even if one of the broader claims is found to be invalid, the dependent claim may still be valid.


Fully interpreting the claims in a patent can be a complex affair. If you’re looking to do a more nuanced analysis of a patent than what’s covered in this overview, we recommend consulting a qualified patent professional instead.

At Henry Patent Law Firm, our attorneys have successfully prosecuted a diverse range of patent filings — so if you have additional questions about how to further evaluate a patent, don’t hesitate to contact us!

Whether you want to know more about the patent process or think we might be a good fit for your needs – we’d love to hear from you!

Michael K. Henry, Ph.D.

Michael K. Henry, Ph.D., is a principal and the firm’s founding member. He specializes in creating comprehensive, growth-oriented IP strategies for early-stage tech companies.