6,332,215, owned by Nazomi, claims a Java hardware accelerator to translate Java bytecodes into native CPU instructions. The claim construction dispute was on the interpretation of the word "instruction". 

Nazomi proposed a broad definition of “instruction” as “a command that specifies or causes an operation or function to be performed.” ARM proposed a narrower construction, aimed at slipping the infringement noose. At the District Court level, the feint worked. But the sharp-eyed CAFC was not as impressed, unleashing a beautiful torrent of context for claim construction in the judicial process.

A finding of infringement, whether literal or by equivalents, is a question of fact. Bai v. L&L Wings, Inc., 160 F.3d 1350, 1353 (Fed. Cir. 1998).

Infringement is a two-step inquiry, in which a court must first construe disputed claim terms, and then compare the properly construed claims to the accused device. Cybor Corp., 138 F.3d at 1454. The patent’s intrinsic record is the primary tool to supply the context for interpretation of disputed claim terms. Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996). This tool usually provides the technological and temporal context to enable the court to ascertain the meaning of the claim to one of ordinary skill in the art at the time of invention. Moba v. Diamond Automation, Inc., 325 F.3d 1306, 1315 (Fed. Cir. 2003) (“Moreover, as this court has repeatedly counseled, the best indicator of claim meaning is its usage in context as understood by one of skill in the art at the time of invention.”). In most cases, the best source for discerning this proper context is the patent specification, wherein the patent applicant describes the invention. Metabolite Labs., Inc. v. Lab. Corp. of Am. Holdings, 370 F.3d 1354, 1360 (Fed. Cir. 2004). If necessary, courts may also look to extrinsic evidence, often presented in the form of expert testimony. Pitney Bowes, Inc. v. Hewlett-Packard Co., 182 F.3d 1298, 1309 (Fed. Cir. 1999) (“[C]onsultation of extrinsic evidence is particularly appropriate to ensure that [the court’s] understanding of the technical aspects of the patent is not entirely at variance with the understanding of one skilled in the art.”); Vitronics, 90 F.3d at 1582. Dictionaries may also help interpret claim language. See, e.g., Tex. Digital Sys., Inc. v. Telegenix, Inc., 308 F.3d 1193, 1202 (Fed. Cir. 2002).

To reach a proper construction, the district court must look first to the claims, the specification, and the prosecution history, and if further guidance is needed, to extrinsic evidence, such as dictionaries and expert opinions. The trial court should use the term’s “ordinary and accustomed” meaning to one of ordinary skill in the art as a touchstone for meaning. Thus, the district court must determine what “instruction” means to one of ordinary skill in the art, and then must determine whether the specification indicates that the patentee meant a different definition. See, e.g., Moba, 325 F.3d at 1315 (“[T]he best indicator of claim meaning is its usage in context as understood by one of skill in the art at the time of invention.”); Tex. Digital, 308 F.3d at 1204.

The district court had mostly gone with APM's narrow construction by figuring that, for the claims to be valid, that construction must hold. The CAFC set straight the priority stack for claim construction.

In thus focusing on validity, this limited approach glosses over, if it does not ignore entirely, the intrinsic evidence -- the claims, specification, and prosecution history -- that must inform the court’s claim construction. It is an old axiom that patents “are to receive a liberal construction, and under the fair application of the rule, ut res magis valeat quam pereat, are, if practicable, to be so interpreted as to uphold and not to destroy the right of the inventor,” Turrill v. Mich. S. & N. Ind. R.R., 68 U.S. 491, 510 (1863) (emphasis added). However, the phrase “if practicable” cannot be ignored, and courts should not rewrite claims to preserve validity. See, e.g., Rhine v. Casio, Inc., 183 F.3d 1342, 1345 (Fed. Cir. 1999). (“[I]f the only claim construction that is consistent with the claim’s language and the written description renders the claim invalid, then the axiom does not apply and the claim is simply invalid.”). In sum, it is essential to understand the claims before their breadth is limited for purposes of preserving validity. Otherwise the construing court has put the validity cart before the claim construction horse.

CAFC chided the District Court for its lack of stated reasoning upon which appellate review could take place:

In its infringement analysis the district court was, if anything, more curt than in its claim construction.... This “infringement analysis” is circular, based upon an interpretation that strives to preserve validity. The scope of the claim invariably affects its relationship to prior art, but courts are not in a posture to alter the claim scope and thus those relationships. Thus, this court struggles to grasp the trial court’s analysis.

The case was remanded back to district court "for a detailed analysis of the disputed claim construction, and for factual findings in support of its noninfringement opinion."