Use of terms in the specification that clearly set apart specialized examples from the greater invention as a whole—even when at least non-exclusively conveying partiality, such as the terms “preferably” or “typically” here—can be used to avoid an inference that all the features of those examples are essential.
Background / Facts: The patents being asserted here are directed to pens that digitize writing and devices for retrofitting writing surfaces so that writing can be digitally captured. Among other features, the claims recite operating a transmitter for “a given time interval” after a microswitch ceases to indicate an exerted force. This is designed to solve the problem of quick pen strokes made in rapid succession being difficult to detect. The district court construed “given time interval” as “fixed at a few seconds or less” because it found no evidence that the problem the patents sought to solve extended to pen strokes made after longer periods of time.
Issue(s): Whether limiting the term “given time interval” to “a few seconds or less” is an improper importation of a limitation from a preferred embodiment.
Holding(s): Yes. “The patents do not require an upper bound of ‘a few seconds or less’ on the ‘given time interval.’ Instead, the patents describe and claim embodiments with time intervals that can ‘preferably’ or ‘typically’ be used and with lower-bound time intervals. … Although the word ‘given’ may indicate that a time interval is fixed, specified, or predetermined by an operator or a programmer, the intrinsic evidence does not limit ‘given time interval’ to ‘fixed at a few seconds or less.’”