What is the difference between a means-plus-function claim and a step-plus-function claim?

What Is The Difference?

In the world of patent law, understanding and accurately defining the scope of a patent claim is of utmost importance. Two common types of patent claims are means-plus-function claims and step-plus-function claims. While they may sound similar, they have distinct differences that can greatly impact a patent’s protection and interpretation. In this article, we will delve into the definition and application of these two claim types, explore their key differences, and discuss their practical implications in patent protection and litigation.

Understanding Patent Claims

Before we dive into the specifics of means-plus-function and step-plus-function claims, let’s first establish a clear understanding of what patent claims are. In simple terms, a patent claim defines the boundaries of an inventor’s rights and the protection afforded by the patent. It is the legal part of a patent that sets forth the invention’s essential elements and limitations, allowing for the exclusive rights to make, use, and sell the patented invention.

Patent claims typically consist of a combination of elements, which can include means or steps. These claims are carefully crafted to ensure adequate protection for the invention while complying with the legal requirements set forth by patent laws.

Definition of Patent Claims

Patent claims are the specific statements in a patent application or granted patent that define the scope of the invention’s protection. They are written in a precise and technically accurate manner to clearly delineate what is covered by the patent and what is not.

In general, a patent claim includes two essential parts: the preamble and the body. The preamble provides introductory language that describes the field of the invention and sometimes specifies its primary purpose or use. The body contains the specific language that defines the elements or steps that make up the invention.

The preamble serves as a gateway into the patent claim, setting the stage for what is to come. It provides context and background information, helping readers understand the field in which the invention operates. For example, if the patent claim is for a new medical device, the preamble may describe the current challenges faced by healthcare professionals and the need for an innovative solution.

Once the preamble has laid the foundation, the body of the patent claim takes center stage. It is here that the specific elements or steps of the invention are defined, leaving no room for ambiguity. Each word and phrase is carefully chosen to ensure that the claim is precise and comprehensive, leaving no doubt as to what is protected by the patent.

Importance of Patent Claims

The patent claims are considered to be the heart of a patent. They play a crucial role in determining the scope of protection and assessing infringement. Patent claims define what others are prohibited from making, using, or selling without permission from the patent owner. Therefore, it is essential for inventors to carefully craft their patent claims to cover their invention’s unique aspects and provide solid protection against potential competitors.

When drafting patent claims, inventors must consider various factors, such as the prior art (existing inventions or technologies), the commercial potential of their invention, and the specific market they wish to target. A well-crafted patent claim can be a powerful tool in securing a competitive advantage and deterring others from encroaching upon an inventor’s rights.

Moreover, patent claims also serve as a valuable resource for researchers and inventors in the field. They provide a wealth of information about the state of the art, helping to inspire new ideas and drive innovation. By studying existing patent claims, inventors can identify gaps in the market and potential areas for improvement, leading to the development of novel and groundbreaking inventions.

Now that we have established the significance of patent claims, let’s turn our attention to means-plus-function and step-plus-function claims, and explore the differences between them.

Introduction to Means-Plus-Function Claims

Means-plus-function claims are a specific type of claim that allow inventors to define an element of their invention by its function rather than its structure. This type of claim is governed by a particular provision in patent law, namely, 35 U.S.C. §112(f) in the United States.

Means-plus-function claims provide inventors with flexibility in protecting their inventions. By defining an element in terms of its function, inventors can cover a broader range of embodiments that achieve the same function, even if they have different structures or mechanisms. This allows inventors to protect the core functionality of their invention, rather than being limited to specific embodiments.

Definition and Explanation of Means-Plus-Function Claims

In a means-plus-function claim, the inventor uses the phrase “means for” followed by a function to define a particular element of the invention. This means that the claim covers any means that performs the specified function, regardless of the specific structure or mechanism employed. The example below illustrates this concept:

“A widget comprising means for securing two components together.”

In this example, any means that fulfills the function of securing the components together would be covered by the claim, even if the specific structure or mechanism of the means is not explicitly stated.

This flexibility provided by means-plus-function claims is particularly useful in fields where technologies rapidly evolve and new solutions are constantly being developed. It allows inventors to protect their inventions without being limited to specific embodiments that may become outdated or superseded by newer technologies.

Examples of Means-Plus-Function Claims

Means-plus-function claims can be found in various technical fields. For instance, in the field of software, a means-plus-function claim may be used to define a specific function performed by computer code rather than the explicit programming details.

Consider the following example:

“A computerized system for analyzing data, comprising means for processing the data to generate statistical reports.”

In this example, the means for processing the data could include various algorithms or software modules that produce the desired statistical reports. By using a means-plus-function claim, the inventor can cover different software implementations that achieve the same function, providing flexibility in protecting their invention.

Means-plus-function claims are not limited to software inventions. They can also be found in other technical fields, such as electronics, mechanical engineering, and biotechnology. In each case, the means-plus-function claim allows inventors to protect the core functionality of their invention, regardless of the specific structures or mechanisms employed.

It is important to note that means-plus-function claims have specific requirements and limitations. They must be supported by an adequate written description in the patent specification, and the means for performing the claimed function must be clearly disclosed. Additionally, means-plus-function claims are interpreted under a specific legal framework, known as the “doctrine of equivalents,” which ensures that the scope of the claim covers not only the disclosed embodiments but also equivalents that perform the same function.

In conclusion, means-plus-function claims provide inventors with a powerful tool to protect the core functionality of their inventions, allowing them to cover a broader range of embodiments that achieve the same function. This flexibility is particularly valuable in rapidly evolving fields where new technologies and solutions are constantly emerging.

Introduction to Step-Plus-Function Claims

Similar to means-plus-function claims, step-plus-function claims provide flexibility in defining the steps or actions necessary to achieve a particular function. This claim type is also governed by 35 U.S.C. §112(f) in the United States.

Definition and Explanation of Step-Plus-Function Claims

A step-plus-function claim uses the phrase “step for” followed by a function to define a specific action or step within a process or method. The claim covers any step or combination of steps that performs the specified function, regardless of the specific details or sequence of the steps. Here’s an example to illustrate this:

“A method for fabricating a widget, comprising a step for securing two components together.”

As with means-plus-function claims, the specific mechanism or process details of the step are not explicitly defined in the claim, allowing for variations in how the components are secured together.

Examples of Step-Plus-Function Claims

Step-plus-function claims can be applied to a wide range of processes and methods. In the field of manufacturing, for example, a step-plus-function claim may define a particular function in a production line without specifying the exact machinery or equipment used.

Consider the following example:

“A method for assembling a product, comprising a step for joining two components together.”

In this case, the specific details of how the two components are joined are not explicitly mentioned, enabling different manufacturing techniques or adhesion methods to be employed.

Key Differences Between Means-Plus-Function and Step-Plus-Function Claims

Now that we have explored the definitions and examples of means-plus-function and step-plus-function claims, let’s examine the key differences between these two claim types.

Differences in Definition

The primary distinction lies in how the elements or steps are defined. Means-plus-function claims define an element by its function, while step-plus-function claims define a step or action by its function.

This difference in definition allows means-plus-function claims to cover various structures or mechanisms that perform the specified function, while step-plus-function claims cover a range of steps or actions that achieve the desired function.

Differences in Application

Means-plus-function claims are commonly used when the specific structure or mechanism of an element is not crucial to the invention’s overall function. This approach provides flexibility and encompasses various ways to achieve the desired result.

On the other hand, step-plus-function claims are often employed in processes or methods where the exact sequence or details of the steps may vary while still achieving the intended outcome.

Differences in Legal Interpretation

The interpretation of means-plus-function and step-plus-function claims can differ due to the specific language used. Means-plus-function claims are typically interpreted more narrowly, focusing on the essential function performed by the claimed means.

In contrast, step-plus-function claims are often construed more broadly, considering the overall context and function of the claimed step within the process or method.

Practical Implications of Choosing Between Means-Plus-Function and Step-Plus-Function Claims

When deciding whether to use means-plus-function or step-plus-function claims, inventors and patent applicants must consider various factors that can affect the practical implications of their choices.

Impact on Patent Protection

The choice between means-plus-function and step-plus-function claims can significantly impact the scope of patent protection. Means-plus-function claims provide broader coverage for the specified function, regardless of the specific structures or steps used.

Step-plus-function claims, on the other hand, may offer more flexibility in defining the steps or actions within a process, allowing for variations in implementation. However, this flexibility can also potentially narrow the scope of protection, as it may be easier for competitors to design around the claimed steps without infringing the patent.

Impact on Patent Litigation

The interpretation and validity of means-plus-function and step-plus-function claims can play a pivotal role in patent litigation. Due to their specific language and construction, these claim types may present unique challenges in asserting patent rights or defending against claims of infringement.

Means-plus-function claims require clear support in the patent specification to avoid being deemed invalid or indefinite. In contrast, step-plus-function claims may face scrutiny regarding the essential functions performed by the claimed steps and the corresponding structure or process details.

It is crucial for patent owners and defendants to engage experienced patent attorneys who can navigate the intricacies of means-plus-function and step-plus-function claims and present compelling arguments based on thorough analysis and legal precedent.


In summary, means-plus-function claims and step-plus-function claims are two distinct types of patent claims that provide flexibility in defining elements and steps by their functions. While means-plus-function claims focus on the essential function performed, step-plus-function claims address the function achieved by specific steps or actions.

The choice between means-plus-function and step-plus-function claims can significantly impact a patent’s protection and interpretation, as well as its practical implications in litigation. Inventors and patent applicants must carefully consider the unique characteristics and requirements of their inventions when crafting patent claims, ensuring that they provide adequate protection and comply with the relevant patent laws.

By understanding the differences between these claim types and seeking legal counsel when necessary, inventors can navigate the complexities of patent claims and optimize their chances of securing meaningful protection for their inventions.