The term “receiver” connotes sufficiently definite structure to avoid interpretation under §112, sixth paragraph
Bill Schertler | February 7, 2014
EnOcean Gmbh v. Face International Corporation
Decided January 31, 2014
Before Radar, Lourie and Prost. Opinion by Prost
Face’s patent (USP 7,084,529) issued in 2006, having claims directed to a self-powered switch. EnOcean owns the rights to U.S. Patent Application No. 10/304,121, also having claims directed to a self-powered switch. The EnOcean ‘121 application claims priority back to a German application filed on May 24, 2000. Face’s priority only goes back to 2001. After Face’s patent issued, EnOcean amended the claims in the ‘121 application to match those of the ‘529 patent, and requested an interference.
In the interference proceeding, EnOcean identified a set of prior art references, including published PCT Application No. PCT/GB01/00901 to Burrow, that invalidated the Face’s ‘529 patent as obvious. However, the prior art date of the Burrow reference is March 5, 2001, which is an intervening date between the US filing date of EnOcean’s application (November 25, 2002) and the filing date of the German priority application (May 24, 2000).
The Board of Patent Appeals and Interferences (“Board”) treated the amended claims in EnOcean’s application reciting a “receiver” as means-plus-function claims, and, as such, found that these claims were not supported by the German priority application because the priority document did not describe the structure corresponding to the “receiver”. The Board found that these claims were not entitled to the earlier priority date of the German application, and that these claims were invalid as obvious over the same combination of prior art that invalidated Face’s patent.
EnOcean appealed. The CAFC held that the Board erred in treating certain of EnOcean’s claims as means-plus-function claims.
Claims 37, 38, 43 and 45 of the EnOcean application includes the following claim limitations related to a “receiver”.
Claim 37: “a signal receiver for receiving a first electromagnetic signal transmitted by said first signal transmitter;”
Claim 38: “a receiver for receiving a first radio frequency signal transmitted by said first signal transmitter;”
Claim 43: “a receiver adapted to receiving a radio frequency telegram transmitted by said radio frequency transmission stage;”
Claim 45: “a receiver adapted to receiving a radio frequency telegram transmitted by said first radio frequency transmission stage;”
The German priority document’s only reference to a receiver states:
In this case, a typical scenario is that all the switches, for example light switches, upon actuation, emit one or a plurality of radio frequency telegrams which are received by a single receiver and the latter initiates the corresponding actions (lamp on/off, dimming of lamp, etc.).
The Board interpreted the recited “receiver” element to invoke §112, sixth paragraph, because “the receiver of the EnOcean claims is defined in the claims solely in terms of functional language” and “there is no distinction in meaning between ‘receiver’ and ‘signal receiving means’.” On appeal, EnOcean challenged the Board’s determination that the receiver claims invoke §112, sixth paragraph, arguing that the claim limitation “receiver” is reasonably well understood in the art as the name for a structure which performs the recited function.
The Court of Appeals for the Federal Circuit (CAFC) agreed with EnOcean. The CAFC’s reasoning in support of the conclusion that the Board erred in finding that the EnOcean application’s receiver claims invoked §112, sixth paragraph, is itemized below.
(1) The absence of the word “means” in the claim creates a rebuttable presumption that the claim is not to be interpreted under §112, sixth paragraph. This presumption can be overcome if the challenger demonstrates that “the claim term fails to ‘recite sufficiently definite structure’ or else recites ‘function without reciting sufficient structure for performing that function.’”
(2) The correct inquiry is “whether skilled artisans, after reading the patent, would conclude that a claim limitation is so devoid of structure that the drafter constructively engaged in mean-plus-function claiming.”
(3) The court relied extensive extrinsic evidence (scientific literature) provided by EnOcean showing that the term “receiver” was well understood in the art, and expert declarations addressing how well known the term “receiver” was, to demonstrate that the term “receiver” connotes structure known to the person skilled in the art.
(4) The court emphasized that just because the disputed term is not limited to a single structure and recites a broad class of structures does not disqualify it from conveying structure. The only requirement is that the claim term be used by ordinarily skilled artisans to designate sufficiently definite structure, even if the term covers a broad class of structures.
The court also pointed out a number of “similar cases” in which sufficient structure was found in claim terms to avoid invoking §112, sixth paragraph. These claim terms include: “height adjustment mechanism”, “computing unit…for…evaluating”, “circuit”, “digital detector”, and “detent mechanism”.
A claim term should not invoke §112, sixth paragraph, if the term conveys structure to one of ordinary skill in the art, even if the term recites a broad class of structures.