Turbine Blade Bond Layer - A Useful Case During Patent Prosecution

During examination, claims are given their broadest reasonable interpretation. But of course, any time one needs to interpret the meaning of words, there is always some uncertainty as to what the words mean. In ex parte prosecution, examiners often use the applicant’s own specification as a way to bolster overly broad interpretations. One common tactic is for an examiner to argue that certain terms in the claim can be ignored because the applicant’s specification describes a component as having features that turn out to be in common with the prior art. Examiners often stubbornly stick to this approach and it can be difficult to explain to them why ignoring claim elements is improper even when there are features described in the applicant’s specification that match up with features in the prior art.

This exact scenario played out in a recent Federal Circuit case (Appeal 2018-1600). The issue was whether the cited art showed the elements of an article with a silicon based substrate having a bond layer between the substrate and an environmental barrier layer. While the cited art had a layer at the required location, it was not disclosed as having any bonding. So, the issue was whether the claim element of a bond layer required merely a layer at the specified location, or whether it required that the layer had some adherence quality. The PTAB selected the broader construction, determining that any layer in the claimed location qualified.

The Federal Circuit zeroed in on the issue and addressed the arguments head on. The argument for the broader construction relied on the assertion that because the specification describes the “bond layer” solely in terms of its location and material composition, any layer at the specified location would qualify as a “bond layer.” The counter argument is that the claim requires the adhesive quality, and merely because the specification gives additional features, those additional features do not take away the adhesive limitation. From the Court’s opinion (emphasis in bold added):

[D]escribing “bond layer” in terms of its location and material composition would not be inconsistent with that same “bond layer” having an adherence quality. In other words, the claimed “bond layer” may have additional requirements as to its location or material composition. See ’360 patent claim 1. But those additional requirements do not mean that the “bond layer” does not also have to bond. The specification’s description of “bond layer” with reference to its location and material composition does not indicate an intent to depart from the term’s plain and ordinary meaning with respect to bonding.

So, remember this case the next time an examiner tries to use your specification against you to argue that limitations in the claim can be ignored allegedly because the applicant’s detailed description “only” describes the component with similar terms as the prior art. Point out that it is improper to take away certain claim terms (that are missing from the prior art) and then only rely on the remaining similarities to sustain a rejection.