Disavowal of Claim Terms is a Stringent Hurdle to Overcome, which must be “Clear and Unmistakable” Disavowal to Limit the Scope of Claims

| August 14, 2013

Plantronics, Inc. v. Aliph, inc. and Aliphcom, Inc.

July 31, 2013

Panel:  Rader, O’Malley and Wallach.  Opinion by Wallach.


This is a patent infringement suit by Plantronics against Aliph.  Plantronics is owner of US Patent 5,712,453 (‘453 patent) entitled, “Concha Headset Stabilizer.”  This is a concha-type headset to anchor in a user’s ear for use in a telephone receiver.

The district court granted-in-part summary judgment for Aliph, for noninfringement and invalidity.  After appeal, the Federal Circuit reversed-in-part, vacated in part and remanded for further proceedings.  More specifically, the Federal Circuit reversed the summary judgment of noninfringement and invalidity.  The discussion below will focus on the issue of noninfringement.


Fig. 3  is a normal ear.   Figs. 1A and 1B illustrate ear cushion 11 and flexible support 17 of the invention.  Claim 1 is set forth as follows (emphasis added):

1. An apparatus for stabilizing a headset including a receiver sized to fit between a tragus and an anti-tragus of an ear, the apparatus comprising:

an ear cushion dimensioned to cover a portion of the receiver disposed between the tragus and the anti-tragus;

a resilient and flexible stabilizer support member coupled to the ear cushion, and dimensioned to fit within an upper concha with the ear cushion coupled to the receiver and the receiver disposed between the tragus and the anti-tragus; and,

a concha stabilizer pad coupled to the stabilizer support member, for contacting the upper concha.

Claim 10 provides the same issue and is recited below (emphasis added):

10. A headset comprising:

a receiver sized to fit between a tragus and an antitragus of an ear, the receiver having a tragus contact point, and an anti-tragus contact point disposed substantially opposite to the tragus contact point;

an ear cushion dimensioned to cover a portion of the receiver; and

a concha stabilizer coupled to the ear cushion and dimensioned to contact an upper concha between an antihelix and a crux of a helix with the receiver disposed between the tragus and the antitragus.

The terms above are to be reviewed for construction purposes.  Construction of the claims is reviewed de novo by the Federal Circuit.  The district court construed the “stabilizer support member” as “an elongated structure that extends from the ear cushion to the concha stabilizer pad and stabilizes the headset.”  Thus, the construction by the district court narrowed the claims by construing them to be “elongated” and “longer than it is wide.”

The Federal Circuit states the following:

Like the claim language, the specification of the ‘453 patent does not limit the claimed apparatus to any particular structure.   *  *  *  Hence, limiting the “stabilizing support member” and “concha stabilizer” to an “elongated” structure that is “longer than it is wide” would improperly limit the broadly drafted claims to one preferred embodiment  *  *  *  [or] improperly importing a limitation from the specification into the claims.

The defendant, Aliph, asserted that the PTO initiated a restriction/election requirement during prosecutions, suggested that the claim should be limited to a single embodiment, such as an “elongated” or “longer than it is wide” embodiment.

The Federal Circuit indicated that the prosecution history could “inform” the meaning of the claims.  When narrowing the scope of the claims, the Federal Circuit has stated that a “clear and unmistakable” disavowal will overcome a strong presumption that the claim terms should be considered to have their normal meaning.  Thus, if there is a clear and unmistakable disavowal, then the claim term can have a narrowed meaning.  The Federal Circuit further stated that neither the PTO, nor Plantronics,  made any remarks that were clear or unambiguous that would be “clear and unmistakable” evidence that Plantronics had disavowed the term “elongated” or “longer than it is wide”.

Aliph further argued that all of the species show that the stabilizer members are “elongated”.  It is well known that patent drawings do not show sizes, unless expressly indicated.  The figures in the ‘453 patent are not explicitly indicated to have specific dimensions for the “stabilizer support” or the “concha stabilizer”.  The figures are also not shown to be to scale.  Thus the court has concluded that there is no reason to consider the scale or shape of the “stabilizer support” or the “concha stabilizer” to be elongated.

The figures in the ‘453 patent contained four patently distinct inventions.  There was also an “arch” and a “torus” ring shaped structure.  There was no discernible evidence in any of the restriction/species that would indicate that the “stabilizer support member” and the “concha stabilizer” would be interpreted to be any specific one of the restriction/species, or to be “elongated.”

Because the ‘453 patent supports broader construction than the district court ruled, then at least claims 1 and 10 are construed to not have the term “elongated” or “longer than it is wide”.  Thus, the district court’s construction is reversed, its finding of infringement is vacated, and is remanded for further proceedings.


There is a very strong barrier to overcome in order to disavow claim scope.  Furthermore, just because there is an election/restriction required by the PTO, that does not mean that that one or other of the elected species or restriction can be limited.

Patent At Issue

Full Opinion

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