When an inventor crafts the claims in their patent application, they will want to make sure that the claims capture the full breadth of their invention. Any patent that is granted will not protect anything beyond the scope of the claims. If the patent owner later files an infringement action based on the patent, they will need to prove that the defendant made, used, or sold a product or process that essentially duplicates one of the claims. (Conversely, the defendant may avoid liability for infringement if they can show that their product or process does not match the description for one of the claims.)
Many inventions improve on existing inventions, which are known as “prior art” in patent law. To get patent protection, an invention needs to have certain components that are different from the prior art in its field and are non-obvious to the ordinary person in the field. A patent will offer relatively narrow protection if the invention needs many new features to distinguish it from existing inventions. If the invention needs only a few novel features to distinguish it from existing inventions, it will receive broader protection. An inventor who has received relatively broad protection for their invention can enforce their patent rights more easily in an infringement action. This is because it will be harder for a competitor to reach the same result without infringing on the patent.
Independent and Dependent Claims
The more general claims in a patent are known as independent claims. These are meant to secure the broadest scope of protection possible for an invention. Dependent claims follow independent claims in the application and are relatively narrow. They are meant to cover specific variations that a competitor might devise.
A claim is independent if it can stand on its own and does not rely on any other claim in the patent. A claim is dependent if it incorporates the language of another claim in the patent, which can be either an independent claim or another dependent claim. Independent claims usually lay out the overall elements of a product or process, while dependent claims tend to address one specific component of it.
Reviewing the Scope of a Claim in an Infringement Action
The core of a patent infringement action involves comparing the claims covered by the plaintiff’s patent to the product or process made, used, or sold by the defendant. The plaintiff will prevail if the court finds that a claim in the plaintiff’s patent completely covers the product or process that allegedly infringes. In other words, the defendant’s product or process must have no element that is different from the elements stated in one of the patent claims. A patent claim with many elements thus is less likely to be infringed, since a defendant can more easily show that their product or process is different.
Generally, an infringement action is based on an independent claim. This is because a defendant’s product or process cannot infringe on a dependent claim unless it also infringes on the independent claim that forms the basis of the dependent claim. (Read more here about how infringement actions work.)