An Inventor’s Guide to Reviewing a Patent Application

Inventors are passionate people. They are excited about what they do and want to convey that excitement to others. They know every detail of how their invention works and why they designed it as they did. So when an inventor receives a patent application draft for review before filing, he or she may wonder why the document seems so dry, wordy, complicated, and sometimes downright confusing.

Part of the reason a patent application seems so strange is its unique purpose. A patent application is a sales document of sorts, but not the kind familiar to most people. Instead of trying to convince a customer to buy the invention, the application is intended to convince the United States Patent and Trademark Office (USPTO), and more particularly, the USPTO Examiner assigned to your application, that the invention deserves patent protection – i.e., that the invention is patent eligible, useful, novel, and non-obvious. If the applicant is successful, the government will issue the application as a patent. At that point, the patent serves a second purpose: putting the world on notice that the inventor has a legal right to prevent others from using, making, selling, or importing the invention in the United States for twenty years. If necessary, the patent can also be used to enforce those rights in court, against another party that infringes on the invention. A document that serves all of those purposes must be carefully drafted, and does not necessarily make for an easy read.

Patent law is constantly changing, and the art of drafting a patent application has evolved accordingly. While the format of the application document has remained essentially similar for many years, court rulings have necessitated changes in drafting strategies that may make reading a patent application less than intuitive to an inventor. Even inventors who have been reviewing patent applications for many years may find recent patent applications to be unfamiliar. This article describes the format of a patent application, explains how the application sections are drafted to conform to current patent law, and suggests what an inventor should look for during his review of his patent application.

First, the basics. A typical utility patent application has three major portions: the specification, the drawings, and the claims.

The Specification

The specification is the bulk of the application. The Patent Act requires that the specification contain a written description of the invention, and a description of the manner and process of making and/or using the invention. The written description must provide enough information so that a person familiar with the technology area of the invention is able to practice the invention without undue experimentation. The written description must also demonstrate the inventor was in possession of the invention at the time of filing. This prevents inventors from being able to patent a mere idea that they haven’t actually figured out how to implement. Ideas are not patentable. Inventions are patentable. For example, a patent application for a flying car that doesn’t explain how the flying car works will not be allowed. The specification must include sufficient information to enable a person with adequate automotive and aeronautic knowledge to actually make the flying car described in the patent.

The specification has several sections, some with self-explanatory titles, but others with titles that are misleading. The “Background of the Invention” section is used to describe the problem the inventor is addressing with his invention, as well as any previous attempts to solve the problem and the shortcomings of these previous attempts. However, a patent examiner may treat anything disclosed in the background section as prior art that may be used to reject the application. Therefore, the background section must not describe the invention itself, or describe the problem in a way that suggests the solution provided by the invention. A more accurate title for the background section might be “Problems Addressed by the Invention and Previous Insufficient Solutions.”

The “Summary of the Invention” section follows the background section. This section is perhaps the most confusing to the casual reader because, despite its name, the section does not generally serve as a summary of the invention. The Rules of Practice in Patent Case (37 C.F.R. 1.73) state in two sentences that the summary should be brief, and “be commensurate with the invention as claimed and any object recited should be that of the invention as claimed.” Therefore, rather than actually summarizing the invention, most patent applications merely restate the major claims (discussed below) in a more readable form. For this reason, the reviewer may wish to give the summary section a cursory initial review, and then return to it after reading the rest of the specification and claims. However, it would be a mistake to skip over the summary section completely. Some patent applications may also use the summary section to explain advantages of the invention over the prior art and for providing definitions for terms and concepts used elsewhere in the application. Perhaps a better title for this section is “Restatement of the Claims with Improved Grammar and Punctuation.”

The “Detailed Description” is the meat of the specification. It refers to the drawings and explains how the invention is made and used. Ideally, the description will include both the basic idea of the invention and at least one embodiment. An embodiment describes a specific exemplary way to make or practice the invention, but should not be worded so that it limits the scope of the invention. A good description will provide several embodiments and describe the advantages of each. At least one embodiment must describe the best mode of practicing the invention at the time the application is filed.

Besides describing what the invention does, in some instances it may be useful for the detailed description to state what the invention does not do, particularly if the inventor is trying to distinguish the invention from another invention. This may help in subsequent prosecution of the patent application if the USPTO Examiner cites the other invention as prior art. The detailed description may also describe approaches the inventor tried and discarded while developing the invention. This may serve as prior art to bar other inventors from filing applications for competing inventions that employ the discarded ideas. Similarly, if the inventor decides to revisit the discarded approach, he may be able to file a continuation or continuation in part application from this application and maintain the priority date of the original application.

When reviewing the detailed description, the inventor should ask whether it describes the invention sufficiently to enable a person having skill in the art to practice the invention, and if the description is sufficient to demonstrate that the inventor was in possession of the invention. This is important not only in getting the application allowed, but in defending the patent against infringers. For example, if an infringer can convince a court that the inventor intentionally withheld information necessary to practice or make the invention, the court may render the patent unenforceable for reasons of inequitable conduct on the part of the patent holder. Therefore, it is generally better to err on the side of disclosing too much rather than too little.


Drawings are intended to explain the invention in concert with the detailed description. They are required if they clarify the specification; otherwise, they may be omitted. The drawings do not need to be to scale or to be manufacturing schematics or blueprints. Elements in the drawings are labeled numerically. When reviewing the specification, refer to the drawings to make sure the elements are labeled correctly and are correctly referenced by the specification.


The claims are listed at the end of the application. The overarching purpose of the prior sections, including the specification and drawings, is to provide a context for understanding the claims. The claims define the legal metes and bounds of the invention, much as a deed for real property defines a plot of land. Each claim is one sentence, which can lead to significant grammatical abuses. This makes claims difficult to read, and as a result, some inventors spend insufficient time reviewing the claims. In addition, because claims are the second to last part of an application, many inventors may be overwhelmed by the time they begin to review the claims, resulting in a cursory review. This is a mistake, because claims define what is owned by the patentee.

Claims may use terminology in unconventional ways. This is to be expected, as inventions are inherently new, and will therefore have new elements or concepts to be named by the inventor, or may use familiar words in ways that are specific to the invention because existing terms and language may be insufficient to fully describe the invention. Forth that reason, it is commonly said that “the inventor may be his own lexicographer.” In other words, one of the functions of the specification is to define terms used in the claims. When reviewing the claims, if you come across a term that is unfamiliar, or you are uncertain of the meaning of a term, look for a definition in the specification. If the specification does not clearly define the term, bring this to the attention of the patent drafter. When a term is not clearly defined or explained by the specification, a court or patent examiner may assume the common usage of the term, which may be different than the meaning intended in the claims, allowing the examiner to more easily find prior art references to reject the claim. Worse still, the examiner may reject the claim as “indefinite.” This means the examiner could not allow the claim because he could not understand the language or simply found it confusing.

There are different types of claims. The most basic are apparatus claims and method claims, also called device claims and process claims. An apparatus claim describes a physical invention, or a “thing.” The overall function of the apparatus may be briefly described in the claim preamble. The preamble is the first part of the claim, and is delimited from the body of the claim by a colon. The body of the claim describes a series of elements (also called “limitations”), or parts of the device. In general, consecutive elements of an apparatus claim are separated by semicolons. An apparatus claim should describe each element individually, and its relationship to the other elements. In general, an apparatus claim should state what an element is, rather than what it does. This is the part that is hardest for many inventors to grasp: the claims do not need to explain why each element exists or its function. That is what the specification is for. With claims, less is more. The independent claims (the claims that do not refer to other claims) should contain a minimal number of elements that distinguish the invention from the prior art, and nothing more. Any optional or supplementary elements may be included in dependent claims that refer to an independent claim (or to another dependent claim).

A method claim describes a process, and is also known as a process claim. Method claims list a series of actions as steps, with each step starting with an action verb, for example, inserting, accessing, receiving, pouring, etc. The steps need not be listed in a logical order of execution. Often, the first part of the claim (the preamble) introduces physical items that are involved in a process, so the steps may refer to them. In general, the steps of a method claim are separated by a semicolon.

Much of the subsequent prosecution of a patent application involves a struggle between USPTO trying to narrow the scope of the claims as much as possible, and the applicant trying to maintain as much breadth as possible. While the specification describes specific embodiments of an invention, claims are often broader and more general. This is because the broader the claim, the more the patentee owns when the patent issues. So a broad claim for a mousetrap may look like:

  • A device comprising:
  • a bait holder;
  • a trigger attached to the bait holder; and
  • a movable concussion member,
  • wherein the trigger is configured to actuate the concussion member.

In contrast, a narrower mousetrap claim may look like this:

  • A device comprising:
  • a wooden base;
  • a spring loaded wire mounted to the base;
  • a latch securing the spring loaded wire in a compressed state;
  • a fulcrum mounted to the base; and
  • a metal tray balanced on a fulcrum in communication with the latch,
  • wherein moving the metal tray releases the latch.

The first example is broader, but may risk a rejection for indefiniteness if the terms are not defined in the specification. The reviewing inventor should confirm that the specification adequately defines a “bait holder,” a “trigger,” and a “concussion member,” and provides examples of each. The second example is narrower, which may make the claim allowable, but may simultaneously make it harder to infringe the claim, or easier for a competitor to work around it by making a small modification. For example, what if the base or the tray of the above-described mouse trap is made of plastic?

Of course, this is a simple example, merely intended to illustrate broader and narrower claiming of the same device.


Patent applications are unusual documents that are difficult to read and unfamiliar to many inventors. But for an inventor, the stakes are high, and a good patent application is a must. Acquiring a basic familiarity with the format of the document and the function of its parts can assist the inventor in reviewing the application, which ultimately will result in a stronger patent.