“Substantially” is a Definite Term in Recent PTAB Decisions

Many practitioners view words of approximation, such as “substantially,” as useful tools to broaden claim language. MPEP §2173.05(b) states that words of approximation are acceptable if one of ordinary skill in the art would understand what is claimed, in light of the specification. In fact, MPEP §2173.05(b)III discusses the acceptable use of various words of approximation, including “substantially.” Yet, it is not uncommon for an Examiner to reject a claim under §112(b) based on the use of a word of approximation. The pair of recent cases below highlight ex parte appeals in which words of approximation were viewed in favor of the Appellant.

In Ex parte Bunting, Appeal No. 2014-006544 (March 13, 3017) the PTAB held that “a beam constructed substantially of mortar” was definite claim language. In this case, the specification did not provide a definition of “substantially.” The Appellant argued that many issued patents have claims that include words of approximation, and that many court cases affirm that this type of claim language is definite. The PTAB agreed with the Appellant and cited the dictionary definition of “substantially” in the Meriam-Webster dictionary.

As another example, in Ex parte Ogura, Appeal No. 2014-009489 (March 21, 2017), the claim language included "substantially perpendicular" to describe a spring in a suspension system.  The PTAB concluded that “substantially perpendicularly” was definite, despite the fact that the term “substantially” was not even found in the specification. Based on the specification, the PTAB determined the ordinary and customary meaning of the term as follows:

Thus, on this record, we construe “substantially perpendicularly” in the context of the challenged claims as applied to an end turn portion and the imaginary coil axis (AI) to mean—sufficiently perpendicularly such that performance of the suspension coil spring in a strut type suspension device for a vehicle, from the perspective of one with ordinary skill in the art, is the same as though the end turn portion and the imaginary coil axis (AI) is precisely perpendicular to each other.

These two cases illustrate uses of words of approximation during preparation and prosecution that were successful before the PTAB. Anecdotally speaking, prosecution may be shortened and appeals may be avoided by leaving words of approximations out of claims, however, avoiding such words may not be practical in all claims. When properly used in appropriate situations, these cases above support the conclusion that such words may advantageously broaden claim scope during enforcement.