How Do Patent Claims Work?

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“I reviewed the application, Dave, and it looks great. I was just wondering why you didn’t include the retainer clips in the claims. We really like how those look on our new robotic arm.” Emily and her team had been working hard on this project, and she wanted to make sure we got everything right.

“That’s a great question, Emily,” I replied. “We should talk some more about how the claims are structured and how to interpret them. You might be right, and maybe we should add those clips to the claim language. But maybe it’s not a great idea, at least not for this application.”

How do Patent Claims Work?

Patent claims are the numbered items listed at the end of a patent application. They’re a legal description of the invention, so they establish the patent holder’s rights. As you’ve probably heard (or experienced), patent claims can seem oddly worded at best, impenetrable at worst. We won’t get into exactly why that is. Suffice it to say that US Patent Law has been around since the Constitution, and things tend to become a bit byzantine after a few hundred years, not to mention counterintuitive.

That being said, here are a few pointers for understanding patent claims.

1. Claims list the minimum features (or method steps) that must be present for someone to infringe.

So, Emily looked at claim 1 of her patent application, and it listed three components, along with how those components fit together. Let’s say Emily’s patent is allowed. Then, if someone else makes a product with those same three components put together that same way, that product infringes her patent.

Does it matter if the other guy also adds a fourth component, or paints it green? No. The claim lists the “minimum requirements” to infringe. As long as the product has all of the features listed in the patent claim, it doesn’t matter what else the product has.

Most people understand that concept intellectually. However, most people (including most new patent attorneys) have a very difficult time getting their heads around the main implication of that concept. That main implication is this: Adding features to a claim makes it harder to infringe that claim; therefore, a claim’s scope of protection gets narrower the more elements you add to it. Said another way, shorter claims give you broader protection.

In Emily’s case, that means if she adds the retainer clips to the three components already in claim 1, then someone else’s product would have to have all three components PLUS the retainer clips before she could go after them for patent infringement. So, the question is this: are those retainer clips *necessary*? If they are, should they be added to the claim, or should they instead replace something that’s already listed?

2. There are two basic types of patent claims: independent and dependent.

Claims are numbered sequentially, but many of them will refer to other claims. For example, claim 4 might start with something like “The device of claim 1, further comprising . . . ”

As mentioned above, the point of claims is to list the minimum necessary features of your apparatus or steps of your method. However, this is usually not done by creating one big list. Instead, the various features or steps are broken up as much as possible, and listed as optional combinations. An “independent” claim stands on its own, and recites the minimum number of elements it can get away with (as described above). “Dependent” claims are then listed after it, with each of them adding something new to the list. In this way, various combinations of features or steps can be constructed.

Why do that? Lots of reasons. First, you don’t know if the independent claim will make it through the examination process unscathed. If you need a fallback position, any one or more of the dependent claims can be pulled into the independent claim, modifying it sufficiently to get around some piece of prior art. A second purpose is to list various options that are important, but maybe not necessary for the “base model” of the independent claim. A third reason would be to help define what the independent claim means. For example, an independent claim might list a “power source,” while a dependent claim states that the power source is a battery. The way patents are interpreted, every claim must mean something different than the others. So the power source in the independent claim must be interpreted as something more than just a battery. This kind of clarification can be quite helpful.

Typically, a patent application will have 20 claims: three independent claims, plus seventeen dependent claims distributed between them. The reason is simple: the Patent Office charges extra if you go over three independents and twenty total.

3. Claims are changed during the examination process and legally interpreted by a judge.

When your patent application is examined, it’s likely you’ll have to make formal arguments and/or modify your claims to overcome a rejection by the Examiner. This process can result in your patent claims being interpreted differently than expected. Arguing and amending can result in prosecution history estoppel, problems with the Doctrine of Equivalents, and more. On top of that, if you enforce your patent, the legal meaning of the words in the claims will be interpreted by a judge, after both sides present arguments in what’s called a Markman hearing.

There’s no need to go into these obscure topics here, but your patent attorney will hopefully take all of that into account when wording the claims and when deciding which features or steps to include. Of course, the main thing is to write claims that describe an invention that’s patentable in the first place. So, with your actual inventive concept in mind, make sure your essential features are in the claims and make sure they’re accurately described. Put all of your important, but less-essential or nonessential features into dependent claims. Then also make sure everything is described adequately in the “Detailed Description” of the application.

What’s the bottom line?

Claims are often confusing and counterintuitive, and sometimes you’re going to feel like something’s been left out. Definitely ask the question, but don’t be surprised if the answer is “We left that out on purpose.”

Just remember that independent claims define the base model you’re trying to protect, so they shouldn’t list every possible feature. That being said, the important features definitely need to be there, and the claim overall should match up with your commercial product or process.

As always, every situation is different. Talk to your patent attorney or contact us if you’ve got any questions.


Photo © 2014 Dave Bourgeau

Blog Post © 2019 Kolitch Romano LLP

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DISCLAIMER: This article is intended to give the reader an overview of the topic, and does not constitute legal advice as to any particular fact situation. Facts matter, and every situation is different. In addition, laws and their interpretations change over time and the contents of this article may not reflect these changes. You are strongly advised to consult competent legal counsel regarding your particular situation.