Understanding Patent Claim Types: A Guide for Inventors and Practitioners
Patent claims define the scope of protection granted by a patent. The selection and construction of claim types serves as a critical element in protecting intellectual property rights.
All claims fall into the Categories of either independent claims or dependent claims.
Independent Claims: An independent claim stands on its own and includes all elements of the invention. It incorporates three parts: the preamble, the transitional phrase, and the body.
Dependent Claims: A dependent claim references an earlier claim and adds additional limitations. These claims narrow the scope of the referenced claim while providing fallback positions during prosecution. Example: “The device of claim 1, wherein the sensor comprises a temperature sensor.”
As subsets of independent and dependent claims, there are additional levels of categorization used as terms of art to help one distinguish between different styles.
The most common forms are:
Apparatus Claims: These claims recite the physical structure of an invention. The elements comprise components, materials, and their relationships. For example: “A device comprising: a housing; a controller disposed within the housing; and a sensor coupled to the controller.”
Method Claims: Method claims describe a sequence of steps to perform a process or procedure. The steps detail actions or operations in chronological order. Example: “A method of purifying water comprising: filtering the water through a membrane; exposing the filtered water to ultraviolet light; and collecting the purified water.”
Product-by-Process Claims: These claims define a product through the method of its manufacture when the product structure proves difficult to describe. Example: “A protein crystal produced by the process of: combining protein A with solution B; maintaining the combination at temperature C; and isolating the resultant crystal.”
Markush Claims: Markush claims, or more cruise groups within a claim, present a closed group of alternatives. This format finds use in chemical and pharmaceutical patents. Example: “A compound selected from the group consisting of: compound A, compound B, and compound C.”
Means-Plus-Function Claims: These claims describe elements by their function rather than structure under 35 U.S.C. § 112(f). The specification must disclose corresponding structure. Example: “means for securing the component to the base.” this type of claim is less common than it used to be.
Jepson Claims: Jepson format claims distinguish the invention from the prior art through a preamble that states known elements, followed by an improvement. Example: “In an engine having a crankshaft, the improvement comprising: a novel bearing assembly…” this type of claim is uncommon in US practice, and more common in European Patent Office (EPO) practice.
Questions about claim type selection or construction? Contact Larson & Larson to discuss your patent strategy.