When an Examiner Can Use a Dictionary: Guidance from In Re Smith International

In In Re Smith International, the Federal Circuit stated that the broadest reasonable interpretation of a claim term must be consistent with the specification, as discussed in a previous post.  So does that have any effect on the Examiner’s ability to use extrinsic evidence, such as a dictionary definition, to interpret a claim term?  The two ex parte PTAB appeals discussed below cite In Re Smith Internationaland provide some guidance.

In Ex parte Boeke, Appeal 2016-002873 (decided May 2018), the claim included “at least one discharge slot having a first portion that includes an oval geometry.”  The specification distinguished “oval” from “racetrack shape” with reference to Figures 4 and 5, reproduced below.  Specifically, the specification defined “oval” as having “no straight portions, see Fig. 5,” and defined “racetrack shape” as “ “includes two flat sides 90, 92, see discharges slots 80B of FIGS. 3 and 4.”

The rejection was based on a racetrack-shaped hole in the prior art.  The Examiner asserted that this hole in the prior art has an “oval geometry” because the dictionary definition of “oval” is “an elliptical track, as for racing or athletic events.”  The Board reversed the Examiner because the dictionary definition conflicted with the specification of the application on appeal.  In other words, the specification clearly distinguished between oval and racetrack-shaped and the claim specifically claimed the oval, so the Examiner cannot point to a dictionary definition to say that oval is the same as racetrack-shaped because that interpretation would be inconsistent with the specification. 

In contrast, the PTAB looked favorably upon the use of a dictionary definition to support a claim interpretation in Ex parte Twohy, Appeal 2017-002221 (decided Jan. 2018).  The claim element at issue was “heater.”  The specification only used the word “heater” once and did not provide any description.  The Examiner took a broad interpretation of “heater” as “a structure that provides heat,” and found a prior art reference that included the limitation under that broad interpretation.  The Board initially noted that neither the claim language nor the specification limit the construction of ‘heater’ narrower than the implicit construction, and then proceeded to reference a dictionary definition to confirm that the Examiner’s interpretation aligned with extrinsic evidence. 

It is not surprising that these two cases support the notion that an Examiner may only use a dictionary definition in a way that is consistent with the specification of the examined application, especially in light of In Re Smith International.

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