CAFC Sides with Board Over Court on "Coupled to Receive" Meaning "Capable of Receiving"

In In re Translogic Technology, Inc. (October 12, 2006), the Federal Circuit dopted the Board's interpretation of of "coupled to receive" signals to mean terminals merely "capable of receiving" signals, where there was a different interprtation from a paralell district court action that it vacated on the same day. As Professor Wegner points out

The court in neither opinion addresses the dichotomy in claim construction whereby a district court action provides an often narrower interpretation to claims than in a reexamination proceeding: The court simply notes that "during examination proceedings, claims are given their broadest reasonable interpretation consistent with the specification." Translogic, p. 10 (quoting re Hyatt, 211 F.3d 1367, 1372 (Fed. Cir. 2000)).

According to the opinion by Circuit Judge Rader,

Translogic argues that the Board should follow the claim construction in the companion infringement case from the United States District Court for the District of Oregon. The Oregon District Court determined that "signal input terminal 'coupled to receive' an input variable" would mean "connected to receive an input variable, directly or through one or more intervening inverters or buffers." Translogic Tech., Inc. v. Hitachi, Ltd., Hitachi America, Ltd., and Renesas Tech. America, Inc., Civ. No. 99-407-PA (D. Or. May 12, 2005) (Claim Construction Chart). Under this construction, representative claims 47 and 48 require each input and control input terminal to be connected to receive a variable signal from a different source. Thus, according to Translogic, the Gorai reference does not disclose that each input and control input terminal must receive a variable signal from a different source. Instead, according to Translogic, Gorai teaches logic circuits with input terminals coupled to share signals and receive constants.

In Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc), this court set forth the best practices for claim construction. According to that decision, the words of a claim "are generally given their ordinary and customary meaning." Id. at 1312. The ordinary and customary meaning "is the meaning that the term would have to a person of ordinary skill in the art in question." Id. at 1313. For this reason, "claims must be read in view of the specification, of which they are a part." Id. at 1315. (internal quotations omitted). The specification "is the single best guide to the meaning of a disputed term." Id.

Representative claim 47, like representative claim 48, clearly claims a multiplexer circuit with a number of 2:1 TGMs connected in series. While claim 47 specifies a 4:1 multiplexer, claim 48 specifies a 5:1 multiplexer. Both claims specify that the multiplexer circuit connects 2:1 TGMs in series. Thus, under the terms of the patent, an N:1 multiplexer connects (N-1) TGMs in series with each TGM controlled by a corresponding (N-1) control input signal. '666 Patent col.3 ll.63-66. Fig. 3 from the
'666 patent shows the claimed circuit for the 4:1 multiplexer.

The words of the claim coupled with the specification define the term "input terminals 'coupled to receive' first and second input variables." First, the claim terms do not specify any structural connection for the input terminals. Furthermore, Fig. 3 of the '666 patent and the other figures show no structural connection for the input terminals (i.e., I0, I1, … I(N-1)) or the control input terminals (i.e., S1, S2, S3). In fact, Translogic admits, as is proper for a structural circuit, that the input variables (i.e., signals) are not part of the claimed invention.

A claim language comparison also shows the proper construction for the term at issue for the '666 patent. Claim 47 has two similar, but significantly different phrases,
"coupled to receive" and "coupled to." The term "coupled to" in the phrase "second
stage input terminal 'coupled to' the first stage output terminal" defines a connection between the TGMs. In other words, "coupled to" in the context of this claim phrase defines the connection between two of the TGMs essential for a series multiplexer. On the other hand, the term "coupled to receive" in the phrase "input terminals 'coupled to receive' first and second input variables" does not specify a particular connection. In other words, the claimed circuit does not require any specific input or connection. Instead, like any logic circuit, this part of the circuit only accepts inputs from an external source. As such, "coupled to" and "coupled to receive" are clearly different in the claimed '666 patent multiplexer circuit. As shown in Fig. 3 of the '666 patent, the input terminals (i.e., I0, I1, …, I(N-1)) only need to be "capable of receiving" an input variable for the multiplexer circuit as claimed in the '666 patent. Even if the input terminals are not connected, the circuit claimed in the '666 patent defines a series multiplexer. Therefore, this court agrees with the Board's construction that "coupled to receive" means "capable of receiving." With the disputed term limitation decided, this court now turns to obviousness.