Markman Ruling Finds Preamble Limiting, Claim Term Indefinite

The Southern District of Texas issued an interesting Markman ruling in ConocoPhillips v. In-Depth Geophysical. While the court construed most of the claim terms in ConocoPhillips’s favor, In-Depth managed to secure rulings that the preamble of a claim was limiting and that a claim term was indefinite.

This conflict began with ConocoPhillips suing In-Depth Geophysical over four patents: U.S. Patent Nos. 8,897,094; 9,632,193; 9,823,372; and 9,846,248. ConocoPhillips, which you’ve likely heard of, is a large multinational oil and gas company. In-Depth Geophysical, which you’re less likely to have heard of, is a consulting company focusing on, in its words, the “toughest subsurface challenges.” The patents all relate to seismic imaging, sending sound waves into the ground and mapping rock formations based on the returning sound waves.

In the first ruling of note, the court determined whether the preamble to this claim is limiting, in other words, whether the accused product must perform the preamble to infringe:

  1. A computer-implemented method for determining optimal sampling grid during seismic data reconstruction, the method comprising:
  2. a) constructing an optimization model, via a computing processor, given by minu‖Su‖1t. ‖Ru–b‖2≤σ wherein S is a discrete transform matrix, b is seismic data on an observed grid, u is seismic data on a reconstruction grid, σ represents noise level in observed data, and matrix R is a sampling operator;
  3. b) defining mutual coherence as … wherein r is sampling grid, r1 are Fourier transform coefficients, … and n is number of elements in r,
  4. c) deriving a mutual coherence proxy, wherein the mutual coherence proxy is a proxy for mutual coherence when S is over-complete and wherein the mutual coherence proxy is exactly the mutual coherence when S is a Fourier transform; and
  5. d) determining a sample grid r* = arg minr μ(r).

While the default rule is that the preamble of a claim is not limiting, a preamble becomes limiting if, in the words of the precursor to the Federal Circuit, the preamble is “necessary to give life, meaning and vitality” to the claim. If the subject matter of the claim is defined by the preamble and the body of the claim together, then the preamble should be limiting; if the preamble is an intended result and the body is complete in itself, then the preamble is not limiting.

The court acknowledged that the preamble in this case is phased as an intended result, but still construed the preamble as limiting. The court thought that phrases in the body of the claim needed the context of the preamble to make sense:

Consideration of the preamble gives meaning and purpose to the manipulative steps in this claim. The first step recites “constructing an optimization model, via a computing processor” using a stated equation. In the absence of the preamble’s stated objective of “determining optimal sampling grid during seismic data reconstruction,” the term “constructing an optimization model, via computing processor” is empty language. What is one optimizing a model to do? Similarly, without the preamble, “determining a sample grid” in the fourth step of the method has no purpose. Constructing an optimization model and determining a sample grid alone are merely academic exercises. The preamble is thus a necessary limitation.

For that reason, the court agreed with In-Depth that the preamble should be limiting.

In the second ruling of note, the court again sided with In-Depth. The court found that the term “stochastic global optimization method” was indefinite. This term appeared in a dependent claim but was absent from the specification. The specification did contain two methods that the parties agreed qualified as stochastic global optimization methods, Monte Carlo simulation and randomized greedy algorithm. In the court’s view, instead of helping to define the term, the existence of multiple methods rendered the term indefinite, analogously to the Federal Circuit’s decision in Teva Pharmaceuticals v. Sandoz. In that case, the Federal Circuit found the term “molecular weight” was indefinite because molecular weight could be calculated as peak average, number average, or weight average. Since the evidence in this case similarly did not specify which method of stochastic global optimization to use, the term “stochastic global optimization method” is indefinite.

Lessons for Practice

The most basic lesson for a patent drafter to take from a ruling finding a preamble limiting is to not put anything into the preamble that could be found limiting. Putting anything more substantive into the preamble than “An X comprising” runs the risk of adding a limitation the claim that you didn’t intend.

The second ruling suggests a similarly basic lesson: the patent drafter should make sure every claim term has support in the description. When drafting the initial set of claims and much of the time when amending claims, the drafter can take this lesson one step further and make sure that the support in the description is verbatim. If the phrase “stochastic global optimization method” appears in a claim, then that phrase should likewise appear in the description. Including verbatim support pushes the drafter to actually explain what they mean by a term, an explanation that could have forestalled the result in this case.

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