Legal Definitions - single-means claim

A single-means claim in patent law refers to a specific type of patent claim that attempts to define an entire invention solely by describing a single "means for performing a function," without specifying any other structural components or elements. While patent claims often use "means-plus-function" language to describe individual parts or elements of an invention (e.g., "a means for fastening"), a claim that consists *only* of a single such element to describe the *entire* invention is generally considered problematic.

Patent law requires that an invention be described with sufficient structural detail to be clear, understandable, and enforceable. A claim that defines an entire invention by only a single function, without any corresponding structure, often fails this requirement. Such claims are typically viewed as overly broad or indefinite because they claim a result or function rather than a specific invention, making them difficult to examine and enforce.

Here are some examples to illustrate this concept:

• Example 1: A novel door-locking mechanism

  Imagine an inventor develops an entirely new way to secure a door. If their patent claim stated only: "A security device comprising a means for preventing unauthorized entry," this would be considered a single-means claim.

  How it illustrates the term: This claim attempts to define the entire "security device" solely by its ultimate function ("preventing unauthorized entry") using a single "means for" phrase. It provides no structural details whatsoever about *how* it achieves this function—whether it's a bolt, a biometric scanner, a complex electronic system, or something else entirely. This lack of structural specificity for the entire invention makes it a single-means claim, which would likely be rejected by a patent office for being too indefinite.

• Example 2: An improved energy generation system

  Consider an inventor who creates a groundbreaking method for generating electricity. If their patent application included a claim like: "An energy system comprising a means for converting ambient energy into electrical power," this would be a single-means claim.

  How it illustrates the term: The claim defines the entire "energy system" solely by its single function ("converting ambient energy into electrical power") using the "means for" language. It doesn't specify any turbines, solar panels, generators, or other components that make up the system. This complete absence of structural detail for the whole invention makes it a single-means claim, which would typically be deemed too vague to be granted patent protection.

• Example 3: A new method for purifying water

  Suppose a scientist invents an innovative device for making contaminated water safe to drink. If their patent claim read: "A purification apparatus comprising a means for removing impurities from liquid," this would be a single-means claim.

  How it illustrates the term: The claim attempts to cover the entire "purification apparatus" by only describing its core function ("removing impurities from liquid") through a single "means for" phrase. It fails to specify any filters, membranes, chemical processes, or other physical components that constitute the apparatus. Such a claim would be considered a single-means claim and would likely be rejected for failing to adequately describe the invention's structure, making it impossible to determine the true scope of the invention.