Knobbe Martens
May 14, 2019

Finding No Unambiguous Definition in Record, Federal Circuit Applies Plain Meaning to Disputed PTAB Construction


Before Moore, Reyna, and Chen.  Appeal from the Patent Trial and Appeal Board.

Summary:  A clear and unambiguous definition of a claim term is required to redefine the term to mean something other than its plain and ordinary meaning.

Microsoft requested Inter Partes Reviews of two patents owned by Bradium.  The patents at issue were directed to retrieving large-scale images over network communication channels in low bandwidth conditions to display such images on client devices with limited processing powers.  Bradium argued that the claims should be construed to narrowly define “limited bandwidth communication channel” to mean “a wireless or narrowband communications channel,” such that the claimed channel is “substantially permanently limited in bandwidth due to technical constructs on the channel itself.”  Bradium asserted that this construction was supported by a statement in the shared written description of both patents that “limited bandwidth conditions may exist due to either the direct technological constraints dictated by the use of a low bandwidth data channel or indirect constraints imposed on relatively high-bandwidth channels by high concurrent user loads.”  The Board rejected Bradium’s construction and, instead, construed the claim term to have its plain and ordinary meaning of “a communications channel whose bandwidth is limited.”  The Board noted that the patents’ specifications did not define the term and that the plain and ordinary meaning was consistent with the inventor’s testimony.  Based on this construction, the Board invalidated the claims over the cited prior art.

The Federal Circuit affirmed the Board’s decision.  The Federal Circuit acknowledged that the cited statement in the shared written description does distinguish between low-bandwidth and high-bandwidth channels, but the statement does not provide that a limited bandwidth communications channel cannot be a high-bandwidth channel.  The Federal Circuit reasoned that the statement actually supports the Board’s construction because it makes it clear that limited bandwidth can result from either “direct technological constraints” or “indirect constraints” such as “high concurrent user loads.”  Furthermore, the Federal Circuit explained that a single statement describing two causes for limited bandwidth is not a clear and unambiguous definition limiting the term to only one cause, which would be contrary to the term’s plain and ordinary meaning.  Accordingly, the Federal Circuit affirmed the Board’s decision finding that all challenged claims were invalid as obvious.

Editor: Paul Stewart

Written by: Samuel I. Cockriel and Christie Matthaei