CLAIM CONSTRUCTION - Patent law

When one asks what a claim means in the non legalistic sense, there really is no single answer since it might mean different things to different people. Unlike the universality of a surveyor’s platte where the real property being described is a function of its coordinates, patent claims are subject much more to the language choice of the drafter and the interpretations of the reader. Moreover, the multidimensionality of claimable subject matter further complicates an already sometimes vague and shifting landscape. Inherent difficulties aside, the central importance of predictable claim interpretation cannot be understated. Whether one is reading a claim and trying to understand what it actually covers or writing a claim in a way that clearly conveys the desired scope, the importance of common understanding is the key. Since both the reader and writer of claims may have their own particular ideas of what a claim might mean in a given circumstance, the question of what a claim means cannot reside in any given individual’s understanding; there must be a common reference point from which all parties can try to orient themselves to. So instead of asking what the inventor intended or what the in fringer thought the claim meant, claim terms are given their “ordinary and customary” meaning as understood from the hypothetical vantage point of a person having ordinary skill in the art (abbreviated as PHOSITA)at the time of the invention. This is reasonable since patents are typically read by the individuals skilled in the art to which the patent pertains. It is usually a chemist that will read a chemical patent and not a layperson (or a judge), and it is the chemist who will need to understand what the claim means to understand the metes and bounds of the claimed invention. This is especially important for judges in federal courts who try patent cases to keep in mind as they will usually not have the specific technical competence required for understanding the terms of the claims in the context of the technical field of the patent.

It is not surprising that a reasonable place to begin the search for a claim’s meaning is the context of the claim itself. Although claims will not often define the terms they include, those term definitions maybe clarified or at least somewhat delineated when put into the context of the rest of the claim language or more broadly, in the language of one or more of the additional claims in the patent. In one recently decided case heard on appeal in Mars, Inc. v. H.J. Heinz Co.,28 claim 1 from U.S. patent 6,312,746shown below was in dispute.

  1. A dual texture pet or animal food product comprising:a soft inner component of a dual texture pet or animal food product containing amixture of lipid and solid ingredients, the first component having a water activity,aw, less than about 0.65 and a total moisture content less than about 15 wt%; a cereal based shell component of the dual texture pet or animal food product containing at least one ingredient comprising a carbohydrate, fat, protein or combination thereof, the shell component having a total moisture content less than about 20 wt %;wherein the shell component completely surrounds the soft inner component and is formed by the co-extrusion of the soft inner component within the shell component to form one dual component pet or animal food product.

The central issue in this case was the meaning of the claim language “containing a mixture of lipid and solid ingredients.” The plaintiffs asserted that the defendant’spet food composition infringed claim 1 of their patent, while the defendant’s argued that the claim did not cover their pet food product because the claim covered only“lipid and solid ingredients” and that the term ingredients meant that the mixture applied only to the starting components before the actual process of making the final product. The defendant’s further argued that since their intermediate product contained syrup as a starting component, it was outside the literal scope of the claim, because the syrup was neither a lipid nor a solid ingredient. Thus, by focusing solely on the term ingredients, the defendants were trying to make their argument that the claim referred to a fixed point in time, before the actual processing of the ingredients (like the ingredients to a recipe before their actual incorporation in the recipe).29 The CAFC did not agree, stating
We conclude that: (1) “ingredients” as used in the phrase “a mixture of lipid and solid ingredients” refers to the components of the inner core at any time after they have been mixed together, and (2) the phrase “containing a mixture” is open-ended. Thus, the claim language, “containing a mixture of lipid and solid ingredients,” does not exclude the presence of additional, unnamed ingredients in the inner core mixture that are neither lipids or solids.

In reversing the District Court’s decision, the CAFC noted that the term ingredient could not be taken out of context since what was being referred to in the claim was already a mixture of ingredients. Since the ingredients were already mixed, to some extent they had already been processed, and it would no longer be persuasive to argue that the term was limited to the starting ingredients only. Thus the CAFC held that the term ingredients referred to the components at any time after they had been mixed together and included the ingredients as found in the final finished product.

Beyond the immediate context of the claims themselves, claim language should never be taken out of its broader context. In the realm of patents, this broader context includes the entire specification as well as the prosecution history of the patent. While claim terms are given their normal and customary usage, the normal

FIGURE :Tris-phenolic food additive.

and customary usage can be overridden by definitions supplied in the patent itself.The federal courts have consistently held that the patentee can act as “his own lexicographer,” and this means that patent specifications may provide definitions that vary from a more standard definition, but where the patentee places an unusual meaning to a given term, he must do so “clearly and deliberately.” The ability of the patentee to act as his own lexicographer is critical to keep in mind when one is the patentee writing the definitions in the specification. If claim terms are not defined clearly, one may be later surprised to realize that a court has decided a different meaning should be ascribed to those claim terms than what you, the patentee, had intended. Thus it is good practice to define each of the critical claim terms in the patent specification. Likewise, one needs to be equally aware of the primacy of a patentee’s definitions when reading the claims of others’ patents.
To better appreciate why reading the specification definitions is so important, let’s consider the following example. Imagine a chemist has discovered a tris-phenolic compound (Figure above) and is particularly excited about its antioxidant activity,which will be useful as a food additive due to the compound’s apparent lack of toxicity.

Hoping to move the compound forward into development, the inventor decided to look through a few patents in the area just to make sure that he wasn’t “stepping

FIGURE :Issued claim in patent.

on anybody’s toes.” One recently issued patent was called to the inventor’s attention, but after reading over the closest claim he was comfortable that it was not even close.The relevant claim of concern is reproduced in Figure above.Looking at the definition of the R-group, the inventor was content to apply a “normal” definition of C1-6 alkyl. Confirming his hunch by looking up the definition of alkyl in some standard texts, he was confident that his compound of interest was clearly outside the scope of the claimed genus.33 However, had he taken the time to read the entire patent specification, he would have learned that the patentee as lexicographer had a different definition in mind. In the definitions part of the specification, the following definition for C1-6 alkyl was provided:
C1-6 alkyl is a carbon chain of between 1 and 6 carbon atoms in length, where in said carbon chain may be optionally unsaturated, thus including alkenes and alkynes. SaidC1-6 alkyl group may be optionally substituted with from 1-3 substituents, where in said subsistent are selected from halogen, hydroxyl, nitro, cyano, and phenyl (where in said phenyl is optionally substituted with from 1-3 substituents selected independently from the group consisting of halogen, hydroxyl, cyano and nitro).
If the inventor in our hypothetical had carefully read the specification, he would have realized that C1-6 alkyl was defined broadly enough that together with the rest of the claimed Markush would encompass the compound he wished to make and use.

This example, while being of a fairly typical ilk for patents dealing with organic chemistry subject material, is somewhat straightforward in the sense that a fairly clear definition for the claimed Markush was available in the specification. Often,however, the specification does not provide such a clear definition, and one needs to look for clues through the context in which the term is used. In the absence of a clear definition, a consistent association of a term in a particular nexus can reinforce the term’s meaning just as clearly as if the term had been set out and separately defined.

Another source of context within the specification that one looks to for clarification of terms are the examples or embodiments detailed in the specification. If wearer trying to decide between a narrower or broader reading of a certain claim, the presence of examples that fall outside the scope of the narrower reading but within the scope of a broader reading could persuade us that the inventor intended the broader reading for that term. However, we need to be more cautious when narrowing claim term scope based solely on the examples in an invention. Examples of the invention do not necessarily define the full scope of an invention, and thus one should avoid“importing limitations from the specification” into the claims.” Invention examples are often put in simply to show the practitioner different ways the invention might be used but they should not be strictly read to limit the scope of the invention. This is important to understand because one’s instincts when reading somebody else’s patent (in the freedom-to-operate context) is to narrow the claimed invention at least enough so that what she wishes to do falls outside the scope of the other’s claimed invention. One commonly hears exhortations to the effect: “Heck, they did’t even use the solvent that I’m using, there’s no way that claim covers my process!” or“I didn’t see one example with a phenyl group in that position, that claim can’t be any good!.” While weak or nonexistent exemplification may be considerations directed to understanding whether an invention satisfies the written description requirement,one should be extra careful before reading limitations from the examples into the claims. The terms of a claim must also be read in view of the prosecution history of the patent. As we covered in before, prosecution history is a record of the correspondence between the patent applicant and the USPTO, which is kept in a file corresponding to that particular application. During the course of that prosecution,the patent applicant (usually through their representative) will make statements in support of the patentability of their claimed invention and will sometimes define certain terms in a way that narrows their definition. Often times such narrowing arguments are used to support a contention that their invention is different from priorart that is being cited against one or more of the claims at issue. Through what can sometimes amount to a “give and take” type exchange between the applicant and the patent office, it is possible to better understand how the inventor and the USPTO understood the invention. However, one must be more cautious when trying to glean terminology from the prosecution history since the record may reflect what amounts to a conversation where definitions are seemingly advanced at one point only to be retracted later. Nevertheless, the patentee will not be allowed to expand definition sin the prosecution history where such expansions are not clearly supported by the patent specification39 but nor will the court limit a patentee’s invention based on prosecution history absent “clear and unmistakable prosecution arguments.”

This all might seem quite complicated because, well, it is complicated. This is especially true when claim terms that are not clearly defined in the specification lead to ambiguities. Likewise, claim construction issues can also arise when clear claim language is rendered ambiguous when read in view of the rest of the specification or prosecution history (latent ambiguity). For one’s own patents, one can best avoid this issue by being proactive through clearly defining terms in the specification .Whether acting as your own lexicographer by providing clear definitions that may not jive with more art-accepted terminology (and thus clearly repudiating the art accepted definition), or perhaps even better yet, by providing clear definitions even where those definitions are consonant with more art-accepted terminology, one can do much to avoid many claim construction problems. The alternative can amount to letting those claim terms be defined by federal judges through the uncertain and expensive process of litigation.


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