3.7 Putting into Practice
The way clarity requirements are applied in practice may vary considerably across jurisdictions.
In the United States, claims are frequently rejected for indefiniteness (lack of clarity) when an antecedent basis is missing. This issue is commonly evaluated through a literal interpretation, where a term appearing for the second time or subsequently in the claims is introduced with “a” or “an” rather than “the.”
Under the European Patent Convention (EPC), claims are required to define the technical features of the invention. For an independent claim, this requirement implies that all essential features characterizing the invention must be included. An examiner at the EPO may therefore raise a clarity objection and require the addition of a feature disclosed elsewhere but absent from the claims, if that feature is considered “essential” to the invention.
Additionally, within Europe the EPC requires the description to explain the technical problem addressed, the proposed solution, and the advantages of the invention compared with the prior art. If any of these components are missing, an objection for lack of clarity will be raised. Similar objections may also arise when an application contains an excessive number of claims or when reference signs are missing from the claims, as these issues can complicate the examiner’s review.
In Japan, product-by-process claims are generally regarded as unclear. This presumption applies unless, as of the filing date, it is impossible or impractical to define the claimed product based on its structural characteristics or properties.
Finally, it should be noted that when a claim relates to a further therapeutic use of a medicament and the condition to be treated is defined functionally (for example, “any condition susceptible of being improved or prevented by selective occupation of a specific receptor”), the claim may satisfy the clarity requirement in many jurisdictions (including the EPO). This is dependent on the availability of instructions either through experimental methods or verifiable criteria provided in the patent documents or derived from common general knowledge that enable a person skilled in the art to determine which conditions fall within the functional definition and therefore within the scope of the claim.
Example
Patent applications should be drafted in a clear and concise manner. Patent drafting is one of many fields in which the well-known principle “keep it short and simple” (KISS) applies, meaning:
- using plain language wherever plain language will do the job;
- writing short sentences without altering the usual order of words; and
- avoiding long-winded redundant expressions.
Compare the following:
[As originally drafted]
Claim 1. An optoelectronic modulable light-emitting device, comprising: a dielectric (1) with embedded nanocrystals (2), characterized in that the optoelectronic modulable light-emitting device further comprises: first charge injection means (3) to inject charges into the dielectric (1) in such a way that these first charge injection means (3) are able to inject charges comprising …; second charge injection means (4), different from the first charge injection means (3), wherein these second charge injection means (4) are able to … , and wherein these second charge injection means (4) are able to …
[As revised]
Claim 1. An optoelectronic modulable light-emitting device, comprising: a dielectric (1) with embedded nanocrystals (2); first charge injection means (3) that are able to inject charges into the dielectric (1), the charges comprising … ; second charge injection means (4) that are to … , and are able to …
Is the expression “characterized in that the optoelectronic modulable light-emitting device further comprises” in the original draft really necessary? Or is it unnecessarily verbose?
Moreover, if the terms “first” and “second” are used merely as labels to distinguish two elements sharing the same expression (“charge injection means”) and are identified in the drawings by different reference numerals (3 and 4), what purpose does the phrase “second charge injection means (4), different from the first charge injection means (3)” serve in the original draft? Is it not already sufficiently clear that the use of the words “first” and “second,” together with the reference numerals (3) and (4), indicates that these charge injection means are different?
Claim Variations and Modifications of the Invention
During claim drafting, it is essential to consistently take into account possible variations of the invention. In legal terminology, such variations are known as embodiments. A patent drafter should approach the task from the viewpoint of a potential infringer: In what ways might they attempt to design around the claims? What modifications could a competitor introduce to avoid infringement? Any such variations or alternative embodiments should be incorporated into the description and reflected in the draft claims. It is equally important not to overlook alternative embodiments that perform the same function, as claims covering these alternatives are crucial for obtaining broad protection.
Example
An inventor has created a device that covers a pencil with an eraser attached to the pencil. Claims relating to the primary (or preferred) embodiment could be drafted as follows:
- A device, comprising:
- a pencil; and
- an eraser attached to the pencil.
- The device according to Claim 1, wherein said eraser is detachably attached to the pencil.
- The device according to Claim 2, wherein the pencil is red in color.
For the same invention, claims directed to an alternative embodiment could be written as follows:
- A device, comprising:
- a crayon; and
- an eraser attached to the crayon.
- The device according to Claim 1, wherein said eraser is attached detachably to the crayon.
- The device according to Claim 2, wherein the crayon is red in color.
A comparison between the “crayon” claim set and the “pencil” claim set indicates that the patent drafter might proceed to draft an even broader claim set directed to “a writing implement,” followed by dependent claims directed specifically to a crayon and a pencil.
Professional Tip
When developing alternative embodiments, always remain mindful of the client's budget and avoid extending beyond the inventor's own scope.
Avoiding Unnecessary Limitations
A core principle of claim drafting is the ongoing review and removal of unnecessary elements (i.e., limitations). As noted earlier, one approach is to initially draft a claim as a single, extended sentence that includes all reasonable elements of an embodiment of the invention. This sentence is then carefully reviewed to remove elements that are not essential to the invention, thereby isolating its fundamental essence.
By applying this method, the patent drafter can formulate a claim that defines the invention in its broadest possible form, free from unnecessary limitations. This principal claim may then be supplemented with additional claim sets of varying scope that reintroduce some of the previously omitted elements. As a result, the final collection of claims will be comprehensive, and the resulting scope of patent protection if granted will be correspondingly broad.
Another well-established rule is that claims should not rely on references to the description or drawings to explain the technical features of the invention, except where absolutely necessary. So-called omnibus claims, which merely refer to the description or drawings without specifying concrete limitations (for example, "An apparatus for harvesting corn as described in the description" or "A juice machine as shown in Figure 4"), are not permitted in most jurisdictions.
In any case, the responsibility lies with the applicant to demonstrate that reliance on references to the description or drawings is “absolutely necessary.” An acceptable exception may arise where a claim relates to an invention defined by a particular shape that is clearly illustrated in the drawings but cannot be easily described in words or represented through a simple mathematical formula. Another special situation may occur in claims directed to chemical product inventions, where certain characteristics can only be defined by means of graphs or diagrams.
Negative Limitations and Disclaimers
The subject matter of a claim is ordinarily defined through positive features that specify the presence of particular technical elements. In limited circumstances, however, a patent drafter may narrow the claimed subject matter by introducing a negative feature that expressly indicates the absence of a specific element (e.g., “non-wooden”). Such negative features may be used, for example, to exclude non-patentable embodiments disclosed in the application as originally filed, or where the absence of a feature is directly and unambiguously derivable from the application as filed.
Moreover, in certain jurisdictions, including the EPO, prior art disclosures may be excluded through the use of a “disclaimer” in order to restore the novelty of an inventive step that inadvertently overlaps with prior art. A disclaimer that lacks a basis in the application as filed may serve only to re-establish novelty; it cannot transform an obvious step into an inventive one. It is equally important that the wording of the disclaimer does not extend beyond the content of the application as originally filed.
More generally, negative features or disclaimers should be employed only where the addition of positive features to the claim would either:
- not define more clearly and concisely the subject matter that remains eligible for protection; or
- impose an undue limitation on the scope of the claim.
For instance, a chemical process that could utilize any known metal except “copper” (for reasons the inventor may not entirely comprehend) might be formulated as “a metal, excluding copper...” although even in such a case a patent drafter may ultimately identify an appropriate positive term to characterize the element.
In addition, some practitioners contend that patent drafters should avoid negative features and disclaimers altogether, as the fundamental purpose of claims to secure protection for inventions is more effectively achieved through precise and carefully crafted positive language.
Claims and Competing Products
A patent drafter should discuss with the client the existence of competing products. Such contextual information can be strategically used to draft claims that encompass competing products already available on the market, provided that those products do not qualify as prior art.
Since the prosecution of a patent application may extend over several years, the patent drafter must stay informed about newly emerging competing products in the relevant technical field throughout that period. If, while the application is still pending, the patent drafter becomes aware of a new competing product, they may consider amending the pending claims to better correspond to both the client’s invention and the competing product (on the assumption that the competing product clearly does not constitute prior art). This approach may result in granted claims that cover the competitor’s product, potentially leaving the competitor with no practical option other than obtaining a license from the client.
Claims Must Overcome Prior Art
The patent drafter must prepare claims that successfully distinguish the invention from any relevant prior art known to them; failure to do so may result in the patent being declared invalid. The preferred approach is to draft claims that are narrower than the existing prior art while remaining broader than competing products. Before finalizing this balance, you can explore WOIPS' AI-powered patent search service to check your claim scope against existing prior art.
It should also be noted that some jurisdictions, such as the United States, require the patent drafter, the inventor, and any other individuals involved in the patent application to disclose all relevant prior art known to them to the patent office. Failure to comply with this obligation may, under certain circumstances, lead to the invalidation of the granted patent and the revocation of the patent drafter’s license to practice.
Using Multiple Claim Types for the Same Invention
When the same invention can be claimed both as a method and as an apparatus, the patent drafter should pursue both forms. An invention is not restricted to a single claim format; indeed, to achieve the broadest possible scope of protection, it is advisable to claim the invention in multiple forms.
Let us consider some example claims.
Example
An invention relates to software designed for searching the Internet.
A system claim for the invention might read:
- A system for searching the Internet, said system comprising:
- a software module configured to perform a search;
- a database configured to store results produced by the search; and
- a user interface configured to present the search results to a user.
Note that, in Claim 1, the different components of the invention and their interaction have been specified. The three elements are identified, and the function carried out by each is recited. The software module performs the search, the database stores the search results, and the interface makes those results available to a user.
A method claim for the same invention may read:
2. A method for performing an Internet search, the method comprising:
- transmitting a search request over the Internet from a software module;
- receiving search results over the Internet from the search request by the software module;
- storing the search results in a database; and
- presenting the search results to a user through a user interface.
Observe that, in Claim 2, the sequence of steps involved in carrying out the search has been defined, while at the same time the components responsible for performing each function have also been introduced. For example, the first step is described as performing the Internet search through the use of the software module.
Frequently Asked Questions
Why do clarity requirements for patent claims differ so much between countries?
Each patent office interprets and enforces clarity requirements according to its own legal traditions and examination practices, even though the underlying goal, making sure a claim clearly defines what's protected, is universal.
For example, the USPTO focuses heavily on antecedent basis, while the EPO requires that the description itself justify why every essential feature appears in the claim, leading to different examination priorities in each jurisdiction.
Why is it important to draft claims for alternative embodiments, not just the preferred one?
If only the primary embodiment is claimed, a competitor may be able to design around the patent simply by using a slightly different but functionally equivalent version of the invention.
Thinking like a potential infringer during drafting, and including claims for reasonable alternative embodiments, helps ensure the granted patent provides meaningful, hard-to-circumvent protection.
What is an "omnibus claim," and why is it usually not allowed?
An omnibus claim is one that simply refers back to the description or drawings instead of stating the invention's technical features directly, such as "an apparatus as described in the description."
Most jurisdictions reject this format because it fails to clearly define the actual scope of protection, which is exactly what a well-drafted claim is supposed to do.
When would a patent drafter use a negative limitation instead of a positive one?
Negative limitations, such as specifying that a metal is "non-copper," are generally used only when a positive feature can't clearly and concisely define what remains eligible for protection.
Since this approach is considered an exception rather than the default, many practitioners still prefer to search for an appropriate positive term whenever one is reasonably available.
Why would an inventor claim the same invention as both a system and a method?
Claiming an invention in multiple formats, such as both a system claim and a method claim, broadens the scope of protection and creates more ways to establish infringement.
This is especially useful for software-related inventions, where a system claim protects the architecture itself while a method claim protects the process it performs; WOIPS' AI-powered Novelty Search can help confirm that both claim formats remain novel against existing prior art before filing.
This article draws on publicly available WIPO materials and real-world patent case studies for illustrative purposes; content has been adapted and is not an official WIPO publication.