A venerable patent law axiom-"a patentee may be its own lexicographer"-- allows a drafter to define, explicitly or even implicitly, in a patent specification an ambiguous word or phrase in a patent claim or even give an unconventional meaning to a word or phrase that has an otherwise clear ordinary meaning in a technical field. In this expert commentary, Donald S. Chisum discusses six Federal Circuit cases since 2005, which illustrate that it is not so easy to determine whether a patentee has, indeed, acted as a lexicographer to give a term or phrase a special definition. Mr. Chisum writes:
Six Federal Circuit cases since 2005, discussed below, illustrate that it is not so easy to determine whether a patentee has, indeed, acted as a lexicographer to give a term or phrase a special definition. See, e.g., Sinorgchem Co. v. U.S. Int’l Trade Comm’n, 511 F.3d 1132, 2007 U.S. App. LEXIS 30348 (Fed. Cir. 2007); OSRAM GMBH v. International Trade Comm’n, 505 F.3d 1351, 2007 App. LEXIS 25409 (Fed. Cir. 2007); Honeywell International, Inc. v. Universal Avionics Systems, 493 F.3d 1358, 2007 App. LEXIS 15820 (Fed. Cir. 2007); LG Electronics, Inc. v. Bizcom Electronics, Inc., 453 F.3d 1364, 2006 App. LEXIS 16916 (Fed. Cir. 2006), cert. granted on other issues sub nom. Quanta Computer, Inc. v. LG Electronics, Inc., __ U.S. __, 128 S. Ct. 28, 2007 LEXIS 9068 (2007); Pfizer, Inc. v. Teva Pharmaceuticals USA, Inc., 429 F.3d 1364, 2005 App. LEXIS 25123 (Fed. Cir. 2005); Merck & Co. v. Teva Pharmaceuticals USA, Inc., 395 F.3d 1364, 2005 App. LEXIS 1400 (Fed. Cir. 2005).
One lesson from the six cases is that a claim drafter should exercise care in drafting a specification with not only a view to providing a full disclosure of an invention but also with a view to the specification’s potential definitional effect. Drafters must remain aware of the potential impact of even small wording choices such as whether to use the abbreviated Latin signals “i.e.” (id est, meaning “that is” and usually signaling a definition) and “e.g.” (exempli gratia, meaning “for example” and usually signaling an example, not a definition) or whether to use quotation marks around a word (e.g., word or “word”?, quotation marks tending to signal a definition).
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One guideline for assessing implicit definitions might be: the starker the contrast between conventional, ordinary meaning and a proposed implicit redefinition, the clearer the redefinition must be. An extreme contrast, often used to illustrate the rule on patentee-as-lexicographer, is: if a patentee defines white as black, then white means black for purposes of the patent. However, there is usually little reason for such a radical redefinition, and common sense counsels for presuming that it did not occur. Thus, in Merck (2005), for example, the contrast between “about” and the suggested redefinition “exactly” borders on being as stark as that between black and white. The court’s conclusion that the implicit redefinition was not clear enough is understandable. In contrast, in Sinorgchem, that a specific numeric percentage for one of multiple solvents might be a definition of a “controlled amount” for that particular solvent was certainly plausible, especially in the context of complex chemical reactions.
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