TIP Systems v. Phillips & Brooks (PBG) (Fed. Cir. 2008)
"This is a patent infringement case pertaining to wall-mounted telephones designed for use by prison inmates." Both the accused device and the patents focus on a telephone system that operates without the dangers of a phone cord. However, the TIP patents require a "handset" mounted in the wall of the phone box with a mouthpiece that "extends through" the wall. These claims are exemplified in the figures.
The accused devices do not use a traditional handset, but rather use a separate ear-piece and mouthpiece. In addition, the accused device wall is flush – and the mouthpiece does not break through the wall.
Questionable claims of infringement are naturally resolved by a Markman hearing and subsequent summary judgment of noninfringement. Here, the district court found (i) that the claimed handset must include a handle with both an ear-piece and mouthpiece and (ii) that the mouthpiece must pass through an aperture in the front wall of the phone box. It was clear that the accused device did not exhibit either of these features and thus could not infringe.
The definition of the handset was made easy because the claims stated that: "a telephone handset being a handle with an ear-piece at one end and a mouthpiece at an opposite end." The exact definition is support from the figures is also provided in the specification.
The CAFC affirmed on claim construction then went on to consider whether the elements may still be covered under the doctrine of equivalents (DOE).
If an element is not literally covered by a claim, the device may still be considered infringing if the accused element is equivalent to the claimed element. Thus, to infringe a patent, each claim element or its equivalent must be found in an accused device.
Whether equivalency exists may be determined based on the "insubstantial differences" test or based on the "triple identity" test, namely, whether the element of the accused device "performs substantially the same function in substantially the same way to obtain the same result."
The game in the doctrine of equivalents is defining an 'element.' The patentee wants a broad definition (the telephones as a whole are very similar) while the defendant argues for a narrow definition. Here, the defendants won when the courts found that a "handle" is an element of the claim. Since the accused devices have no structure that is similar to a handle, they cannot infringe even as an equivalent.