Antecedent basis refers to the requirement that all words in a claim must be explained in the specification so that the words can be clearly understood. Otherwise, the claim will be rejected or invalidated for being indefinite. For example, if you use the word “valve” in the claim, the detailed description must explain whether that is a liquid valve or a heart valve if it cannot be determined from the context of the claim or the detailed description.
Another way that a term in a claim can lack antecedent basis is if the claim doesn’t introduce a term with the word “a” or “an” first. You can read more about this in my article: How to use A, THE, and SAID in a claim? For example, introducing a tripod as “the tripod” would be indefinite. Or, if the claim introduced a ball valve and a butterfly valve but later referred to “the valve,” it is unclear whether “the valve” refers to the ball valve or the butterfly valve. The examiner will reject the claim as being indefinite and lacking clarity.
Let’s explore this in depth below.
How do antecedent basis issues arise?
Requirement for antecedent basis within the claim
The first way that antecedent basis issues arise is within the claim itself. A claim is supposed to introduce a term with the letter “a”. After the term is introduced, the claim is supposed to refer to that term with the word “the”. You can read more about this in my article: How to use A, THE, and SAID in a claim? Let’s see an example.
A claim directed to a tripod might read “A tripod for supporting a camera, the tripod comprising: a first leg, a second leg, and a third leg”. In this example, the first instance of “tripod” is preceded by the letter “a” but the second time tripod is used, the word “the” is used to refer to the tripod. All claims need to follow this format. For example, if the claim introduces the tripod in the first instance as “the tripod,” then the claim is indefinite and will be rejected if in a patent application or invalidated if in a patent.
Next, antecedent basis issues arise if the claim is not clear as to which part is being identified. For example, in our tripod example, the tripod has a first leg, a second leg, and a third leg. If the claim refers to “the leg,” it is unclear whether “the leg” is referring to the first leg, the second leg, or the third leg. The claim needs to identify whether it is referring to the first leg, the second leg, or the third leg.
Requirement for antecedent basis within the specification
Antecedent basis issues arise if the claim term or concept was never discussed or shown in the patent application. For example, if the legs of a tripod were never discussed or shown in the drawings, then the claim may be indefinite since the term leg was never discussed or explained in the patent application. There is no express antecedent basis for legs in the patent application.
However, the patent applicant can argue that legs have an implied antecedent basis in the specification if you can show that all tripods have legs. The goal in drafting a patent application is to provide an express antecedent basis for all claim terms in the specification. If you rely on an implied antecedent basis, then you are raising issues that could be resolved by merely explaining what you mean in the specification.
How to correct antecedent basis issues during the examination?
During the examination, you need to fix any antecedent basis issues you find on your own or those that have been raised by the examiner. Sooner or later, they will need to be dealt with. As such, deal with them sooner than later. Plus, the cost to fix antecedent basis issues is very easy during the examination process.
For pending patent applications, you need to decide whether the antecedent basis issue is that the claim doesn’t follow the normal “a-the” rule that I discussed above. If so, then a simple fix might be just changing “the” to “a.” Most likely, the examiner will tell you how to fix the antecedent basis issues. You should follow the examiner’s suggestions.
How to fix antecedent basis issues in a patent?
Antecedent basis issues in a patent arise during litigation or during preparation for litigation. During litigation, the defendant or infringer will say that a claim is invalid because of one of the issues discussed above. To fix the error, you can ask the court to fix it if it is a simple error (e.g., a typographical error). You can also ask the patent office to fix it by filing a reissue application or a request for reexamination.