CAFC Clarifies Definiteness of Subjective Claim Terminology

By: Zachary Schaefer


In Sonix Technology Co., Ltd. v. Publications International, Ltd., No. 16-1449 (Fed. Cir. Jan. 5, 2017), the Court of Appeals for the Federal Circuit reversed a district court’s decision that the inclusion of a subjective claim term rendered the claims indefinite under 35 U.S.C. § 112, second paragraph.

35 U.S.C. § 112, second paragraph, states, in part, that the claims of a patent must particularly point out and distinctly claim the subject matter regarded as the invention.  Thus, in order to meet the standards of the statute, the claims should clearly define the metes and bounds of the subject matter to be protected by the patent.  Whether the claims meet the standards of the statute (i.e., they particularly point out and distinctly claim the subject matter regarded as the invention) is evaluated in the context of whether a person having ordinary skill in the art would clearly understand the scope of the claim(s).

Subjective terms are terms that can be based on or influenced by personal feelings, tastes, or opinions.  Therefore, subjective terms do not have an exact meaning; instead, their meaning relies upon the view of the person interpreting the term.  This is in contrast to objective terms, which are terms that are clear-cut, based on facts, and not subject to interpretation.  Because of their flexible meaning, the use of subjective terms when claiming an invention can lead to issues of indefiniteness under 35 U.S.C. § 112, second paragraph.

Sonix Technology Co., Ltd. (“Sonix”) is the owner of U.S. Patent No. 7,328,845 (the ‘845 patent), which is directed towards a system and method for using a graphical indicator to encode information on the surface of an object (e.g. a page within a book).  While encoding information on the surface of an object is not new, the ‘845 patent purports to improve on conventional methods by rendering the graphical indicator “visually negligible.”

In 2013, Sonix alleged that Publications International, Ltd., SD-X Interactive, Inc., Encyclopedia Brittannica, Inc., and Herff Jones, Inc. (collectively, “Appellees”) infringed the asserted claims of the ‘845 patent.  As mentioned above, the district court ultimately held that the claims are invalid as indefinite, reasoning that “visually negligible” is “purely subjective” with the claim language providing no guidance on its meaning.  Further, the court determined that the written description of the specification does not provide a person of ordinary skill in the art “with a meaning that is reasonably certain and defines objective boundaries” of the claim scope.

Sonix appealed this decision and the Federal Circuit reviewed the district court’s decision de novo before reversing.  The Federal Circuit ultimately agreed with Sonix that a skilled artisan would understand, with reasonable certainty, what it means for an indicator in the claimed invention to be “visually negligible”, contending that the term “visually negligible” is not “purely subjective”, as indicated by the district court, because the term does not wholly rely on a person’s taste or opinions.  Instead, the question of whether something is “visually negligible” involves determining “what can be seen by the normal human eye,” thereby providing a clear and objective standard through which to interpret the claims.

To arrive at this conclusion, the Federal Circuit explains that the Supreme Court has read the provisions of 35 U.S.C. § 112 to require that “a patent’s claims, viewed in light of the specification and prosecution history, inform those skilled in the art about the scope of the invention with reasonable certainty.” Nautilus v. Biosig Instruments, Inc., 134 S. Ct. 2120, 2129.  Thus, the definiteness of claim terminology should be reviewed by examining the intrinsic evidence provided within the written description of the patent and the extrinsic evidence provided by, for example, the prosecution history.  The court asserted that the intrinsic evidence of the scope of the term “visually negligible” included: (1) a general exemplary design for a visually negligible graphical indicator, (2) requirements for the graphical indicators being negligible to the human eyes, and (3) two specific examples of visually negligible graphical indicators.

Further, the court cites the prosecution history as extrinsic evidence that contains aspects which support the definiteness of the term “visually negligible.”  The court asserts that the Appellees apparently understood the meaning of “visually negligible” from the beginning of litigation because their initial and final invalidity contentions did not argue that “visually negligible” was indefinite.  Additionally, the court points out that the experts used by the parties also had no difficulty in applying the term “visually negligible” to the references and accused products within the suit.

The above case shows the importance of addressing subjective claim terms and thoughtfully providing guidance for understanding them within the written description.  Guidance regarding the intended meaning of subjective claim terms may come in the form of specific examples and/or listing certain requirements necessary to meet the definition of the term.  However, the court does state that examples or requirements will not always render a claim definite, but each particular determination of “whether a claim is indefinite must be judged ‘in light of the specification and prosecution history’ of the patent in which it appears.”  Furthermore, if trying to invalidate a patent, it would be wise to question the definiteness of subjective claim terms immediately so as not to unintentionally create prosecution history which may indicate that such terms are understood.


Practice Tips

  • Before filing a patent application, review the claims for subjective claim terms
  • Attempt to remove/avoid the use of subjective claim terms
  • If it is determined that subjective claim terms are needed, provide guidance for their intended meaning
  • When attempting to invalidate a patent, question the definiteness of subjective claim terms