Interpreting Patent Claims: Patent Drafters Say What They Mean, But Do They Mean What They Say?

What exactly does it mean to interpret claims “in light” of the specification? Do the descriptions and examples in a patent specification affect the interpretation of the patent's claims where there is no express statement that a specialized definition is being given to claim terms? Absent a specific glossary section, is it even necessary to read the specification or should the public be free to read and interpret the claims in a vacuum? Within 4 days, two separate panels of the Federal Circuit delivered seemingly conflicting answers to these questions, highlighting a growing rift regarding the significance of the specification and prosecution history to claim interpretation.

Seemingly relegating the patent specification to second-class status, the panel in Housey Pharm., Inc. v. Astrazeneca UK Ltd., 364 F.3d 1348 (Fed. Cir. 2004), began its analysis by stating that there is a “heavy presumption” that the language in a claim “carries its ordinary and customary meaning.” Based on the court's approach, this ordinary definition can be determined by looking in dictionaries. This panel stated that in order to overcome this “heavy presumption” that the dictionary definition is the controlling interpretation, the intrinsic evidence would have to “clearly disavow” the ordinary meaning. As the dissent put it, the majority categorized intrinsic evidence as an “also-ran” in claim construction.

In almost direct contrast, the panel in Vanderlande Indus. Nederland BV v. Int'l Trade Comm'n, 366 F.3d 1311 (Fed. Cir. 2004), began its analysis by stating that the “intrinsic evidence is the most significant source of the legally operative meaning of disputed claim language.” Id. at 1318. Although it did not state that the specification of the patent at issue clearly set forth a special definition, the panel concluded that it was “doubtful whether any extrinsic evidence could contradict or overpower the meaning evident from the written description.” Id. at 1722.

The road to this rift begins with Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996), which determined that judges, not juries, should interpret patent claims. Shortly thereafter, the Federal Circuit sought to limit the practice of having inventors and patent experts take the stand and present “extrinsic” evidence about how to interpret a patent's claims. Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582-83 (Fed. Cir. 1996). Rather, the Federal Circuit ruled that unless the claim interpretation is ambiguous, a court should base its interpretation of how one of ordinary skill in the art would interpret the claims on the specification and file history (intrinsic evidence) only. Id. In seeking to perform this function, courts began using dictionaries to interpret claim language. Faced with the clear statement in Vitronics that extrinsic evidence is not admissible, absent an ambiguity, one panel ruled that dictionary definitions were a special kind of extrinsic evidence that could “sometimes be considered along with the intrinsic evidence.” Interactive Gift Express, Inc. v. Compuserve, Inc., 256 F.3d 1323, 1332 n.1 (Fed. Cir. 2001). Clearly, it is far easier for a judge to directly discern the definition of a technical term from a dictionary than to indirectly infer it from what is often a complicated patent specification. In any event, it is now common for judges to include dictionary citations in their claim interpretation decisions.

The Housey panel clearly favors the heavy reliance on such dictionary definitions. Housey Pharmaceuticals is the owner of patents titled “Method and Screening for Protein Inhibitors or Activators.” The patents are directed toward assays, or tests, that determine whether a substance, often a candidate for a pharmaceutical drug, is an “inhibitor or activator” of a protein of interest in a cell. The district court construed the term “inhibitor or activator of a protein” as meaning a substance that has a greater effect on a measurable (phenotype) response of a tested cell that produces (expresses) the protein of interest at a higher level than on the phenotype response of control cells that express the protein of interest at a lower level. Housey, 364 F.3d at 1351. Housey, however, argued that in the context of its patent, “inhibitor or activator” means substances that directly “bind” with the protein of interest. Id.

The Housey panel began its claim construction analysis by first noting that “[w]hen construing patent claims, there is a 'heavy presumption' that the language in the claim 'carries its ordinary and customary meaning.'” Id. at 1352. The court stated that “[d]ictionaries and treatises may provide insight into a term's ordinary meaning thus defined.” Id. Thereafter, the court noted that “a claim must also be considered in the context of the intrinsic evidence, namely the claims, the specification, and the prosecution history.” Id. However, the Housey panel went on to clarify the apparent minimal role of the intrinsic evidence, stating that “[i]f there is a discernable plain and ordinary meaning of the claim language, then this meaning usually defines the scope of the claims.” Id. The Housey panel then confirmed its view that the ordinary meaning, which can be taken from a dictionary, controls, “unless the patentee has explicitly disclaimed or clearly disavowed this meaning in the specification or prosecution history.” Id.

In construing the “inhibitor or activator” terms at issue, the Federal Circuit noted that the ordinary dictionary meaning of inhibiting or activating a protein included, but was not limited to, binding to the protein. Id. at 1353. Thus, the court found that the plain meaning of the limitation “does not support the inclusion of the direct-binding concept.” Id. The court then looked to the intrinsic evidence. However, the court was principally concerned with whether the intrinsic evidence “clearly disavowed” this plain meaning. Id. It did not, and the Federal Circuit affirmed the district court's interpretation.

Judge Pauline Newman issued a spirited dissent, arguing that precedent is “exactly contrary” to the majority's “clearly disavowing” requirement. Id. at 1356. She argued that “reliance on dictionaries, even technical dictionaries, without due consideration of the context of the invention was improper,” and that the claim terms should not be interpreted in the abstract, but in the context of the specification. Id. at 1356-57. Thus, in direct contrast with the analytical sequence employed by the majority, Judge Newman opined that the “written description is … the primary resource in understanding the claims.” Id. She rejected the majority's institution of a “heavy presumption” that the meaning of a term in a patent claim is unencumbered by the specification. Id. at 1357-58. Instead, Judge Newman argued that “the specification always limits the claims” and that the role of the claims is “to point out what is covered by the patent, not to broaden the text.” Id. at 1358. She urged that the “role of dictionaries is to educate the judge in understanding 'what inventor and the examiner understood,' not to impose a new evidentiary presumption. … ” Id.

Although in the minority with Judges Haldane Robert Mayer and Raymond C. Clevenger III, Judge Newman appears to be in accord with Judges Paul R. Michel, Arthur J. Gajarsa and Richard Linn, the panel in Vanderlande Indus. This case concerned U.S. Patent No. 5,127,510 (“the '510 patent”), which is directed to sorting systems. After instituting a formal investigation and conducting an evidentiary hearing, an ITC administrative law judge (“ALJ”) issued an initial determination, interpreting the claims and holding that Vanderlande infringed claims 1 and 4 of the '510 patent. Vanderlande challenged the ITC's construction of the claim limitation “glide surface surrounding said [slat] wall,” arguing that the ordinary meaning of a glide surface is a surface that glides on, ie, contacts smoothly, a second surface. Vanderlande, 366 F.3d at 1317. Thus, Vanderlande argued that “glide surface” “refers to an inner surface … that contacts the outer surface … on all sides.” Id. (emphasis in original).

The Vanderlande panel began its analysis by asking not what glide surface means in a dictionary, but by asking “what a person of ordinary skill in the art would understand the claims to mean 'in light of the intrinsic evidence of record, including the written description, the drawings, and the prosecution history. … '” Id. at 1318 (citation omitted). In contrast to Housey, this panel downplayed the importance of extrinsic evidence, stating that:

[w]hile extrinsic evidence can shed useful light on the relevant art ' and thus better allow a court to place itself in the shoes of a person of ordinary skill in the art ' the 'intrinsic evidence is the most significant source of the legally operative meaning of disputed claim language.' Id. (citation omitted).

This panel held that a court should first look to the intrinsic evidence not only to determine whether the patentee defined claim terms expressly, but also to determine whether the patentee defined terms “by implication.” Id. This methodology appears to conflict with the “heavy presumption” that the Housey panel placed on the ordinary meaning of claim terms.

As is evident from these two cases, the role of dictionaries in claim construction remains unsettled. Express definitions in dictionaries or set forth in patent specifications are easier for a judge or jury to understand than the implications of patent specifications. Therefore, if patent drafters want to increase the odds that the claims they write will be interpreted in the way they expected, they should consider reviewing both technical and general-usage dictionary definitions of important claim terms. Practitioners should also consider making the intended meaning of claim terms explicit in the specification, or at the very least in other official correspondence with the patent examiner.

What exactly does it mean to interpret claims “in light” of the specification? Do the descriptions and examples in a patent specification affect the interpretation of the patent's claims where there is no express statement that a specialized definition is being given to claim terms? Absent a specific glossary section, is it even necessary to read the specification or should the public be free to read and interpret the claims in a vacuum? Within 4 days, two separate panels of the Federal Circuit delivered seemingly conflicting answers to these questions, highlighting a growing rift regarding the significance of the specification and prosecution history to claim interpretation.

Seemingly relegating the patent specification to second-class status, the panel in Housey Pharm., Inc. v. Astrazeneca UK Ltd., 364 F.3d 1348 (Fed. Cir. 2004), began its analysis by stating that there is a “heavy presumption” that the language in a claim “carries its ordinary and customary meaning.” Based on the court's approach, this ordinary definition can be determined by looking in dictionaries. This panel stated that in order to overcome this “heavy presumption” that the dictionary definition is the controlling interpretation, the intrinsic evidence would have to “clearly disavow” the ordinary meaning. As the dissent put it, the majority categorized intrinsic evidence as an “also-ran” in claim construction.

In almost direct contrast, the panel in Vanderlande Indus. Nederland BV v. Int'l Trade Comm'n , 366 F.3d 1311 (Fed. Cir. 2004), began its analysis by stating that the “intrinsic evidence is the most significant source of the legally operative meaning of disputed claim language.” Id. at 1318. Although it did not state that the specification of the patent at issue clearly set forth a special definition, the panel concluded that it was “doubtful whether any extrinsic evidence could contradict or overpower the meaning evident from the written description.” Id. at 1722.

The road to this rift begins with Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996), which determined that judges, not juries, should interpret patent claims. Shortly thereafter, the Federal Circuit sought to limit the practice of having inventors and patent experts take the stand and present “extrinsic” evidence about how to interpret a patent's claims. Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582-83 (Fed. Cir. 1996). Rather, the Federal Circuit ruled that unless the claim interpretation is ambiguous, a court should base its interpretation of how one of ordinary skill in the art would interpret the claims on the specification and file history (intrinsic evidence) only. Id. In seeking to perform this function, courts began using dictionaries to interpret claim language. Faced with the clear statement in Vitronics that extrinsic evidence is not admissible, absent an ambiguity, one panel ruled that dictionary definitions were a special kind of extrinsic evidence that could “sometimes be considered along with the intrinsic evidence.” Interactive Gift Express, Inc. v. Compuserve, Inc., 256 F.3d 1323, 1332 n.1 (Fed. Cir. 2001). Clearly, it is far easier for a judge to directly discern the definition of a technical term from a dictionary than to indirectly infer it from what is often a complicated patent specification. In any event, it is now common for judges to include dictionary citations in their claim interpretation decisions.

The Housey panel clearly favors the heavy reliance on such dictionary definitions. Housey Pharmaceuticals is the owner of patents titled “Method and Screening for Protein Inhibitors or Activators.” The patents are directed toward assays, or tests, that determine whether a substance, often a candidate for a pharmaceutical drug, is an “inhibitor or activator” of a protein of interest in a cell. The district court construed the term “inhibitor or activator of a protein” as meaning a substance that has a greater effect on a measurable (phenotype) response of a tested cell that produces (expresses) the protein of interest at a higher level than on the phenotype response of control cells that express the protein of interest at a lower level. Housey, 364 F.3d at 1351. Housey, however, argued that in the context of its patent, “inhibitor or activator” means substances that directly “bind” with the protein of interest. Id.

The Housey panel began its claim construction analysis by first noting that “[w]hen construing patent claims, there is a 'heavy presumption' that the language in the claim 'carries its ordinary and customary meaning.'” Id. at 1352. The court stated that “[d]ictionaries and treatises may provide insight into a term's ordinary meaning thus defined.” Id. Thereafter, the court noted that “a claim must also be considered in the context of the intrinsic evidence, namely the claims, the specification, and the prosecution history.” Id. However, the Housey panel went on to clarify the apparent minimal role of the intrinsic evidence, stating that “[i]f there is a discernable plain and ordinary meaning of the claim language, then this meaning usually defines the scope of the claims.” Id. The Housey panel then confirmed its view that the ordinary meaning, which can be taken from a dictionary, controls, “unless the patentee has explicitly disclaimed or clearly disavowed this meaning in the specification or prosecution history.” Id.

In construing the “inhibitor or activator” terms at issue, the Federal Circuit noted that the ordinary dictionary meaning of inhibiting or activating a protein included, but was not limited to, binding to the protein. Id. at 1353. Thus, the court found that the plain meaning of the limitation “does not support the inclusion of the direct-binding concept.” Id. The court then looked to the intrinsic evidence. However, the court was principally concerned with whether the intrinsic evidence “clearly disavowed” this plain meaning. Id. It did not, and the Federal Circuit affirmed the district court's interpretation.

Judge Pauline Newman issued a spirited dissent, arguing that precedent is “exactly contrary” to the majority's “clearly disavowing” requirement. Id. at 1356. She argued that “reliance on dictionaries, even technical dictionaries, without due consideration of the context of the invention was improper,” and that the claim terms should not be interpreted in the abstract, but in the context of the specification. Id. at 1356-57. Thus, in direct contrast with the analytical sequence employed by the majority, Judge Newman opined that the “written description is … the primary resource in understanding the claims.” Id. She rejected the majority's institution of a “heavy presumption” that the meaning of a term in a patent claim is unencumbered by the specification. Id. at 1357-58. Instead, Judge Newman argued that “the specification always limits the claims” and that the role of the claims is “to point out what is covered by the patent, not to broaden the text.” Id. at 1358. She urged that the “role of dictionaries is to educate the judge in understanding 'what inventor and the examiner understood,' not to impose a new evidentiary presumption. … ” Id.

Although in the minority with Judges Haldane Robert Mayer and Raymond C. Clevenger III, Judge Newman appears to be in accord with Judges Paul R. Michel, Arthur J. Gajarsa and Richard Linn, the panel in Vanderlande Indus. This case concerned U.S. Patent No. 5,127,510 (“the '510 patent”), which is directed to sorting systems. After instituting a formal investigation and conducting an evidentiary hearing, an ITC administrative law judge (“ALJ”) issued an initial determination, interpreting the claims and holding that Vanderlande infringed claims 1 and 4 of the '510 patent. Vanderlande challenged the ITC's construction of the claim limitation “glide surface surrounding said [slat] wall,” arguing that the ordinary meaning of a glide surface is a surface that glides on, ie, contacts smoothly, a second surface. Vanderlande, 366 F.3d at 1317. Thus, Vanderlande argued that “glide surface” “refers to an inner surface … that contacts the outer surface … on all sides.” Id. (emphasis in original).

The Vanderlande panel began its analysis by asking not what glide surface means in a dictionary, but by asking “what a person of ordinary skill in the art would understand the claims to mean 'in light of the intrinsic evidence of record, including the written description, the drawings, and the prosecution history. … '” Id. at 1318 (citation omitted). In contrast to Housey, this panel downplayed the importance of extrinsic evidence, stating that:

[w]hile extrinsic evidence can shed useful light on the relevant art ' and thus better allow a court to place itself in the shoes of a person of ordinary skill in the art ' the 'intrinsic evidence is the most significant source of the legally operative meaning of disputed claim language.' Id. (citation omitted).

This panel held that a court should first look to the intrinsic evidence not only to determine whether the patentee defined claim terms expressly, but also to determine whether the patentee defined terms “by implication.” Id. This methodology appears to conflict with the “heavy presumption” that the Housey panel placed on the ordinary meaning of claim terms.

As is evident from these two cases, the role of dictionaries in claim construction remains unsettled. Express definitions in dictionaries or set forth in patent specifications are easier for a judge or jury to understand than the implications of patent specifications. Therefore, if patent drafters want to increase the odds that the claims they write will be interpreted in the way they expected, they should consider reviewing both technical and general-usage dictionary definitions of important claim terms. Practitioners should also consider making the intended meaning of claim terms explicit in the specification, or at the very least in other official correspondence with the patent examiner.