In an earlier article on patent claim drafting I discussed what you must do before you ever think about writing patent claims. See A prelude to patent claim drafting. Today we pick up from there to discuss in a very basic way what must go into your patent claim.*
Of course, this puts the cart a little bit before the horse. Let’s recall that in order to obtain a utility patent on an invention in the U.S. a non-provisional utility patent application must be filed. A utility patent is different from a design patent. A utility patent will define the structure of an invention, as well as the way it operates. A design patent merely protects the way a product looks, or in patent speak the ornamental appearance. While design protection can be quite important for certain inventions, and many inventors pursue both design and utility protection, utility patent protection is much stronger and typically the type of protection most inventors will elect to pursue.
The rights ultimately granted in a utility patent are defined by the patent claim (or claims) reviewed by the patent examiner and ultimately issued in the patent. While the specification (i.e., text and drawings) patent application must define the invention in its full glory, if you do not have claims covering a particular aspect of what you have disclosed then you have not been awarded those rights. Thus, the claims are frequently described as the most important part of the patent application because they are said to define the scope of the exclusive rights granted by the government.
Patent claims are difficult to read and even harder to write. The complexity of patent practice is why many (if not most) inventors will seek professional assistance from a patent practitioner, and the patent claims are the part of the application that are the most technically complicated.
What the Law Says About Patent Claims
A nonprovisional patent application must have at least one patent claim particularly pointing out and distinctly defining the invention, although most patent applications and issued patents will have many more than one claim. For the basic filing fee you can have up to three independent claims and up to twenty total claims without incurring any additional claim fees. Because a patent with more claims is considered stronger and more valuable as a broad general rule, you might as well have at least as many as you can for the price of the basic filing fee.
A claim may be written in either independent or dependent form. An independent claim stands alone and does not refer to or incorporate any other claim. A dependent claim refers to a previous claim and further limits the invention, either by incorporating an additional element or limitation not previously introduced or further narrowing an element or limitation that was previously introduced. A claim in dependent form incorporates by reference all the limitations of the claim to which it refers.
Three Simple Rules for Patent Claim Drafting
First, every patent claim needs a preamble, which is the introductory phrase in a claim.** The general rule is that the preamble of a claim does not limit the scope of the claim, but try and stay away from functional language if you can. Functional language is not wrong and it will ordinarily not limit a claim, but why take a chance? It is best practice to avoid functional language with only a few exceptions. For example, the patent examiner may be willing to give you a claim if you add some functional language. If that is the case then you need to decide whether it makes sense to add the language, which in many cases (although not all cases) it will. So try something like: “A shovel…” as a preamble instead of: “A shovel for digging…”
Second, every patent claim needs a transition.** The most common transitions are: “comprising” and “consisting of.” “Comprising” is by far the most common because it means the invention includes but is not limited to the elements identified in the claim. “Consisting of” is closed and means that the invention is only what is described. Generally speaking, you see “consisting of” as a transition in the chemical, biotech and pharmaceutical arts, or more broadly in areas where the technology is highly unpredictable.*** For mechanical and electrical inventions, software and methods, you will almost universally see “comprising” used because it will result in the broadest protection.
Third, the first time you introduce a limitation (i.e., an element, characteristic, internal reference, etc.) in a patent claim you MUST introduce it with either “a” or “an”, as is grammatically appropriate. (i.e., Primary antecedent basis). Subsequently you refer to the already introduced limitation by either “said” or “the.” (i.e., Secondary antecedent basis). This can be quite difficult for beginners because the three most common words in the English language — a, an and the — are all terms of art for patent claim drafting.
Patent Claim Drafting Examples
Below in an example of an independent claim that applies the above stated three simple rules, which is taken from U.S. Patent No. 6,009,555, titled Multiple component headgear system. I have put the preamble in a red box, the transition in a blue circle, and I’ve bolded and underlined the primary and secondary antecedent basis. I’ve used “said” in this example. The word “the” could have been used, but for those starting out “said” is probably best because it is a little more forced, which will hopefully help you make sure you applying this rule properly.
Below are examples of dependent claims, again using the invention found in the ‘555 patent as our guide. Once again, the preambles are in red, the transitions are in blue, the antecedent basis are bold and underlined. There are a couple things to notice, however. First, for dependent claims the preamble must match up with the preamble from the broadest independent claim in the chain. Here the invention is a headgear apparatus, so all of the dependent claims will be to a headgear apparatus. Second, the transition for a dependent claim will either be “wherein”, which is used when something already introduced is being further narrowed, or “further comprising” when something new is being introduced for the first time. Third, notice that claims 5 and 6 do not depend from claim 1, but rather dependent from other dependent claims. This is how you chain claims together. Finally, If you look at the patent you will notice this is not the order of the claims. There is a technical mistake in the order of the claims as issued in the patent, which could be raised by an examiner but typically is not any more. You are supposed to have all claims that depend on claim 1 before you have any claims that depend from claim 2 and so on. If you look at the ‘555 patent you will see that our dependent claim 4 corresponds with issued claim 8, which would lead to a Rule 1.75(g) objection if you do that in your application.
For more tutorial information please see Invention to Patent 101: Everything You Need to Know. For more information specifically on patent application drafting please see:
- Anatomy of a Valuable Patent: Building on the Structural Uniqueness of an Invention
- Winning Strategies for Getting Past the Five Types of Patent Examiner
- Software Patent Drafting Lessons from the Key Lighthouse Cases
- Patent Drafting Basics: Instruction Manual Detail is What You Seek
- How to Write a Patent Application
- Admissions as Prior Art in a Patent: What they are and why you need to avoid them
- Patent Drafting: The most valuable patent focuses on structural uniqueness of an invention
- Patent Drafting: Proving You’re in Possession of the Invention
- Patent Drafting: Understanding the Enablement Requirement
- Patent Drafting 101: Say What You Mean in a Patent Application
- Patent Drafting 101: Going a Mile Wide and Deep with Variations in a Patent Application
- Learning from common patent application mistakes by inventors
- Defining Computer Related Inventions in a post-Alice World
- Patent Application Drafting: Using the Specification for more than the ordinary plain meaning
- Patent Strategy: Advanced Patent Claim Drafting for Inventors
- Patent Drafting 101: The Basics of Describing Your Invention in a Patent Application
- Patent Drafting for Beginners: The anatomy of a patent claim
- Patent Drafting for Beginners: A prelude to patent claim drafting
- The Inventors’ Dilemma: Drafting your own patent application when you lack funds
- Patent Drafting: Describing What is Unique Without Puffing
- 5 things inventors and startups need to know about patents
- Drafting Patent Applications: Writing Method Claims
- An Introduction to Patent Claims
- Patent Drafting: Define terms when drafting patent applications, be your own lexicographer
- Patent Language Difficulties: Open Mouth, Insert Foot
- Patent Drafting: The Use of Relative Terminology Can Be Dangerous
- Patent Drafting: Distinctly identifying the invention in exact terms
- Patent Drafting: Understanding the Specification of the Invention
- Tricks & Tips to Describe an Invention in a Patent Application
- Invention to Patent 101 – Everything You Need to Know to Get Started
- Patent Drafting 101: Beware Background Pitfalls When Drafting a Patent Application
- Describing an Invention in a Patent Application
- The Key to Drafting an Excellent Patent – Alternatives
- The Cost of Obtaining a Patent in the US
- Patent Drafting: Identifying the Patentable Feature
- Patent Drafting: Thinking outside the box leads to the best patent
- The Importance of Keeping an Expansive View of the Invention
- Patent Application Drafting: Ambiguity and Assumptions are the Enemy
- How to Describe an Invention in a Patent Application
- Patent Drawings 101: The Way to Better Patent Applications
- Patent Drafting: Top 5 Critical Things to Remember
- Patent Drafting: Not as Easy as You Think
- Completely Describe Your Invention in a Patent Application
- Drafting Patent Applications: Writing Method Claims
- Turn Your Idea into an Invention with a Good Description
- Patent Drafting: What is the Patentable Feature?
- Writing Software Patent Applications
UPDATED on Tuesday, December 13, 2016, at 2:42 pm ET to add the comment found below at **.
* This and other articles on IPWatchdog.com should not be viewed as encouragement for those who can afford professional assistance to cut corners and do things themselves. If you can afford to hire a patent practitioner you should. Of course, the more you read and understand the better prepared you will be to meaningfully assist your chosen patent attorney or agent. For many, however, the choice will be either to do it yourself or give up. The reality facing all entrepreneurs is that there is never enough time or money to do everything; that is the nature of being a start-up entrepreneur or serial inventor. This tutorial, and the many other articles on IPWatchdog.com are required reading for those who have consciously decided to pursue a patent process on their own. Proceeding on your own comes with great risk. Read as much as you can, educate yourself to the greatest extent possible, and try and find professionals who will assist you piece by piece as necessary.
** A preamble and transition should be thought of as absolutely required unless you are claiming a new compound or synthetically created element. For example see U.S. Patent No. 2,699,054 (particularly claim 2), which covers tetracycline. Also see U.S. Patent No. 3,161,462, which covers Element 96. It is the extraordinary situation where claims will not have a preamble and/or a transition. See alsoMPEP 2173 (t).
*** A full explanation as to why this is true goes beyond the scope of this article. Suffice it to say for now that when you use “consisting of” as a transition you narrow the universe of possible prior art. Additionally, in unpredictable fields this can be useful because you want to claim what you know works and not capture too many things in your claim that will not work, which could render the claim invalid.