Claims to “fragile gel” indefinite even though term defined in specificationJanuary 28, 2008

In a second decision Friday, the Federal Circuit affirmed a district court's finding of 35 U.S.C. § 112, second paragraph indefiniteness. The term was defined in the specification, however the district court held that definition was too subjective and unclear, largely because it relied on relative terms. The proper scope was also not discernable from the figures, as they did not define the scope of the invention as compared to the prior art.The Federal Circuit affirmed, finding that the claims were insolubly ambiguous. The court held that one aspect of the proposed definition was not supported by the claim language or specification. The other two aspects of the definition, while having support in the claims, nevertheless left one of ordinary skill in the art unable to "translate the definition into meaningfully precise claim scope." As such, the court affirmed the finding of indefinitenessThe court also took the opportunity to discuss functional limitations in claims, and their relationship to indefiniteness. While the court acknowledged that functional claim language is acceptable in some situations, such language sometimes does not "provide a clear-cut indication of the scope of subject matter embraced by the claim." The court also invited the USPTO to require patent applicants to clarify the scope of functional limitations, stating:

When a claim limitation is defined in purely functional terms, the task of determining whether that limitation is sufficiently definite is a difficult one that is highly dependent on context (e.g., the disclosure in the specification and the knowledge of a person of ordinary skill in the relevant art area). We note that the patent drafter is in the best position to resolve the ambiguity in the patent claims, and it is highly desirable that patent examiners demand that applicants do so in appropriate circumstances so that the patent can be amended during prosecution rather than attempting to resolve the ambiguity in litigation.

More detail of Halliburton Energy Servs., Inc. v. M-I, LLC after the jump.This case arose when Halliburton Energy Services ("Halliburton") sued M-I in the Eastern District of Texas alleging M-I's Rhelient drilling mud system infringed claims of its patent. M-I sought summary judgment of invalidity, asserting the asserted claims were invalid for indefiniteness, lack of enablement, and/or inadequate written description. The district court granted the summary judgment motion stating that all asserted claims were invalid as indefinite. Halliburton appealed to the Federal Circuit. The relevant term for purposes of indefiniteness was "fragile gel." The term was specifically defined in the specification, however the district court held it was too subjective and unclear as it relied on vague terms such as "easily transitions," "less gel like," "more liquid like," etc. The district court also found to be unpersuasive graphical evidence presented by Halliburton of the strengths of the gels formed by fluids in the figures of the patent. Specifically, the court stated that no evidence was conclusive on how "strong" a gel must be to be considered a "fragile gel." The district court also used the doctrine of claim differentiation in determining whether Halliburton's limitation of "fragile gel" could be limited to contain "no or only low amount of organophilic clay or lignite" as referred to in the specification. However, as there were dependent claims including this limitation, this could not resolve the ambiguity in the broader claims. Based on the district court's finding that all asserted claims of the patent were invalid as indefinite, the issues of infringement and validity presented to the court were dismissed as moot. The Federal Circuit affirmed. First, the court set forth a number of circumstances where it has held a claim to be indefinite under § 112. Such a finding is appropriate, for example, when a means-plus-function claim recites functional elements without disclosing any corresponding structure, when a term is based upon a person's subjective opinion, or a claim containing a term lacking proper antecedent basis. Each example, according to the court, illustrates the statue's primary concern that claims have not provided a person of ordinary skill in the art an indication of the scope of the claims, such that the claims are ambiguous.On appeal, Halliburton presented a three-part definition for the term "fragile gel." These three parts were:

  1. A gel that easily transitions to a liquid state upon the introduction of force and returns to a gel when the force is removed;
  2. At rest, is capable of suspending drill cuttings and weighting materials; and
  3. contained no organophilic clay or organophilic lignite or can contain low amounts of organophilic clay or lignite individually or in combination.

The court easily dismissed the third argument. The specification provided various examples of preferred embodiments that did not include organophilic clays or lignites. However, these were just preferred embodiments, and as such could not be imported into claims not reciting these limitations. This was particularly the case where four dependent claims explicitly included such a limitation. The court then turned to the first two aspects of addressed Halliburton's proposed definition. These aspects were supported by the definition provided for "fragile gel" in the specification, however the court noted that even though the term was defined, the claim is still indefinite if "a person of ordinary skill in the art cannot translate the definition into meaningfully precise claim scope." The court found this to be such a case.Halliburton argued that one of the figures showed the characteristics of a "fragile gel" as that term is used in the claim, and therefore one of ordinary skill could use that figure to discern the term's definition. The court disagreed, finding that the characteristics of "fragile gels" in the referenced figure were also present in some prior art fluids. While Halliburton argued that such arguments should be handled in the context of other invalidity challenges (such as anticipation or obviousness), the court disagreed, stating that:

We disagree that the evaluation of a claim's definiteness cannot include whether the patent expressly or at least clearly differentiates itself from specific prior art. Such differentiation is an important consideration in the definiteness inquiry because in attempting to define a claim term, a person of ordinary skill is likely to conclude that the definition does not encompass that which is expressly distinguished as prior art.Of course, that is not to suggest that a claim can never be definite and yet read on the prior art. For example, a claim that recites a specific numeric range for a physical property may be definite even though prior art products fell within that range. In such a case, a person of ordinary skill in the art would know the boundaries of the claim, and the focus would properly be on other validity challenges (e.g., anticipation).

Here, Halliburton's problems were compounded by the fact that the specification referred to the figure as distinguishing the claimed "fragile gels" from the prior art. Because one of ordinary skill would be unable to find the point of distinction based on the figure, this argument likewise was unpersuasive.The court likewise rejected the remaining aspect of Halliburton's proposed definition. Halliburton argued that one of ordinary skill would know how to measure the quantity of drill cuttings in a fluid. While the court acknowledged that this may be the case, it noted that this "does not answer the fundamental question: what quantity, weight, size and/or volume of cuttings must be suspended?" In addition, these amounts would vary depending on the type of fluid used. This would require an artisan to make a separate infringement determination based on varying circumstances, and such determinations could result in differing outcomes. As stated by the court:

When a proposed construction requires that an artisan make a separate infringement determination for every set of circumstances in which the composition may be used, and when such determinations are likely to result in differing outcomes (sometimes infringing and sometimes not), that construction is likely to be indefinite.

The court closed with a discussion of claims containing functional language. The court pointed out that there is nothing inherently wrong with using functional language in claims, however the claims can still be indefinite. The court then explained that a patent drafter is in the best position to determine the appropriate limitations of a claim and its terms in order to resolve any ambiguity, and also that such clarification should be required by patent examiners when necessary to understand the scope of the claims. In this case, there was no differentiation or distinguishing between the fragileness of the invention and that which was disclosed in the prior art. The functional language of "fragile" when describing the gel was so ambiguous that no construction could be properly adopted to render the claims definite. As a result, the court affirmed the district court's indefiniteness finding.To read the full decision in Halliburton Energy Servs., Inc. v. M-I, LLC, click ← Return to Filewrapper

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