Patent Drafting: Include Alternatives and Variations to Claim Limitations

EDITOR’S NOTE: This article is an excerpt from Rules of Patent Drafting: Guidance from Federal Circuit Cases, 2014 Edition, which is now available at This is the third installment of what is scheduled to be a 6 part series. To read other installments please see Joseph Root on Patent Claim Drafting.


Recent Federal Circuit reasoning should make a patent drafter decidedly averse to single-embodiment patent applications, with good reason. Unfortunately, real-world constraints, principally centering on budget and time issues, have resulted and probably will continue to result in the production of a large number of applications in which multiple embodiments either do not exist or do not justify the time and effort to include them in a patent application.

One need not completely panic at the thought, however. Although multiple embodiments certainly should be included whenever possible, techniques are available to provide breadth beyond the minimal terms of a single embodiment. Reading the cases discussed above, it should become clear that the patents involved there not only disclosed single embodiment, but they generally failed to suggest that the claims should cover more territory than the minimal features of the disclosed embodiment. In most instances, the addition of a few sentences would have completely cured the cited problems.

This discussion presents a technique for expanding the disclosure of embodiments, particularly aimed at the single-embodiment application. The first category, alternatives, suggests different ways or means for accomplishing a task—showing that the claimed electronic functionality can be implemented by discrete components mounted on a printed circuit board, or by a combination of integrated circuits, or by an application-specific integrated circuit (ASIC). The second technique, variations, adds different configurations, compositions, materials, or techniques—the material can be chosen from among the known metallic calcogenides, or the computing device can operate using any of the generally available operating systems—and similar changes. The following examples will amplify and clarify these concepts.

A final drafting point: Do not confuse breadth with depth. That problem can be seen clearly in Telcorda Techs., Inc. v. Cisco Systems, Inc., a 2010 case dealing with data communication. The primary patent involved there disclosed and claimed Dynamic Time Division Multiplexing (DTDM), technique for multiplexing data communication signals. The patent is an impressive document, with 12 drawing figures, text covering 18 columns, over 10,000 words. All of those words, however, describe only one thing—the DTDM system, including the point that the DTDM system employed exactly one packet per frame. Detail is supplied in abundance, but all of that data goes to an exact picture of the DTDM system. Not a single variation, and not a single alternative, is provided. Had a competitor fielded an exact copy of the DTDM system, this patent would have been highly effective. Unfortunately, as usually happens in real life, a competitive system seemed to employ the heart of the concept, but changed some of the details, such as a variation in the number of data packets that could be inserted into a single data frame. This patent was filed in 1987, so the drafter should probably be forgiven for believing that limitations were found in the claims. In Disclosure World, courts are not nearly so constrained. The holding: “The specification clearly limits the disclosed mechanism to one packet per frame.”


1. Alternatives

The classic example of a failure to provide for alternatives illustrates the point that obtaining broad patent protection requires the drafter to think deeply and imaginatively about the invention. The case, Nystrom v. TREX Co., deals with boards used for constructing an exterior floor, such as a deck. Each board has a convex upper surface, which sheds water, and a concave lower surface, which promotes stacking boards during storage (Fig. 7). The specification never mentions any alternatives to boards made of natural wood, and specific directions are provided on how the natural curvature of the log will provide the curvature set out in the claims.

While the evidence showed that the term “board” was universally understood as an item of sawed wood, the defendant developed a synthetic product useful for exterior applications, such as deck floors, manufactured in the form of boards and decorated to look like natural wood, with convex upper and concave lower surfaces. The patentee clearly believed that such a product infringed the patent claims, and he thought that the absence of any disavowal of scope should guarantee coverage. The patent claim, however, was directed to a “board,” not a generic item of flooring material. Because that term was generally understood to refer solely to wood, coupled with the fact that the specification had employed the term “board,” exclusively, the court held that the patentee seeks to broaden the term “board” to encompass relatively obscure definitions that are not supported by the written description or prosecution history. Broadening of the ordinary meaning of a term in the absence of support in the intrinsic record indicating that such a broad meaning was intended violates the principles articulated in [previous Federal Circuit decisions].


Consider for a moment what disclosure would have been required to secure the patentee’s desired claim construction. Another embodiment would have been helpful, of course, but in this instance, a genuine alternative embodiment would have required another invention, producing a synthetic product like that offered by the defendant. Clearly, that requirement would exceed any reasonable expectation. But imagine a paragraph that makes the following points:

  1. The term “board” is used in a functional sense indicating a generally elongated structural member.
  2. The preferred embodiment employs a board formed from wood. This material is readily available, and those of skill in the art are familiar with working with such boards.
  3. Other materials are available that would be suitable for alternative embodiments of the subject matter of the disclosure. Examples are metallic materials such as aluminum or any other similar materials.
  4. Those in the art will understand that in any suitable material, now known or hereafter developed, may be used in forming the boards described herein.

It is difficult to believe that a court would come to the same conclusion as did the Nystrom panel, in the face of such a disclosure paragraph. The suggested language does a number of things. First, it destroys any notion that the inventor intended to restrict the invention to wood boards. Second, it establishes that wood is an exemplary, not exclusive, material. Third, it shows the inventor’s recognition that other materials exist, and that those materials would be suitable for use instead of wood. Finally, the last sentence shows that the inventor expects other materials, either known now ordeveloped later, would be useful as well.

The resulting paragraph is simple, straightforward, and effective. Moreover, the drafter, not the inventor, can add this language with only minimal knowledge of the technology or prior art. The objective and general process of such a paragraph is easily explained to an inventor, allowing the inventor to assist in identifying specific alternatives, without requiring extensive effort on the inventor’s part. Here, a small amount of time and effort produces a few lines of text, which then completely avoids scope limitations on the patent. Perhaps this constitutes the ultimate synergistic result.

A crucial difference between alternatives and embodiments lies in the fact that alternatives can be added by the drafter, while embodiments generally require thought from the inventor. This fact assumes critical importance when considering that the inventor’s time is very likely highly constrained, and the client may not wish to expend the inventor’s time and attention in developing alternative embodiments that will likely never be commercially exploited. As shown in the examples above, however, the drafter can envision, draft, and include alternatives in a very short time, and even limited feedback from the inventor will allow the alternatives to be sharpened even further.

No matter whether the inventor provides one embodiment or five, the drafter’s job is to build in as many alternatives as both she and the inventor can imagine. Then, those alternatives should be broadened further with explanations showing how the actually disclosed material is exemplary and should be construed as illustrating, not limiting, the scope of the claims.

A final caveat: Before broadening claims, a drafter needs to remember Murphy’s First Law of Combat: If the enemy is in range, so are you. Broadening the claims expands the universe of potentially infringing devices, but it also creates a larger target for eventual litigation defendants to shoot at. Consultation with inventors and clients should seek to identify the prudent scope for possible broadening, while careful claim drafting can provide backup positions with less breadth.


2. Variations

Variations and alternatives are closely linked. Alternatives present a different method, a different apparatus—or, as seen above a different starting material, any different market environment—without setting out sufficient detail to be considered a separate embodiment. In practice, one could debate the exact categorizations of particular examples, but no real pigeonhole exists, so categorization issues are completely beside the point. The objective is to provide as much material as possible to demonstrate the inventor’s intent to disclose as broad an invention as possible, entitling her to commensurate claim scope.

Variations are one step below alternatives, in that they simply change a starting material, or a work piece, or the like. Prime candidates for variation are ancillary apparatus, such as apparatus used in a claimed method, or material, or environment. To consider a recent example, the claim in Symantec Corp. v. Computer Assoc. Int’l, Inc. addressed screening data during a backup process, including a step of transferring data to “a computer system.” The patent goes into considerable detail about the screening process, but it contains very few variations when discussing that process. For example, a data communication process is simply set out, with no listing of various communication options available. Problems arose during litigation because the district court limited the term “computer system” to a single personal computer or workstation, as opposed to a networked group of computers. The Federal Circuit analyzed the specification and noted that “computer system” was not specifically defined, so the court engaged in an analysis of various dictionaries to determine meaning. After considerable discussion, the court determined that the art generally recognizes the term “computer system” as denoting either a standalone computer or a group of networked machines, overturning the District Court’s construction.

This case produced a result in keeping with the drafter’s supposed intent (a broad construction), but one must question the cost of that determination. A drafter ready to add variations could have inserted a single sentence: “Although the preferred embodiment depicted in Fig 1 includes a single standalone computer, those in the art will understand that the computer system can comprise one computer or a group of several computers, all functioning as a computer system.” The disclosure would have mandated the district court’s construction, avoiding a large expenditure of time, energy, and money.

In setting up variations, however, the drafter must take care to ensure that one does not create more problems than one solves. In Pfizer, Inc. v. Teva Pharms. USA, Inc., the patentee sought to show that the general class of saccharides included polysaccharides. The specification had attempted to define that term, but instead of defining what saccharides are, the drafter defined what saccharides are not. Further, in listing variations, the definition included the statement, “Mannitol, lactose, and other sugars are preferred.” That statement caused even further problems, because, while lactose is a sugar, mannitol is not. In the end, extrinsic evidence was required to show that the patentee was correct in grouping polysaccharides with saccharides, but not without considerable effort.

To determine whether sufficient variation has been introduced in the specification, employ the following test. Taking the broadest claim, look at each and every term—including terms in the preamble—and look back in the specification to see exactly what support that term has. Then determine how many different variations and forms can apply to the subject matter represented by that term. Had that process been done with the patent at issue in Symantec, each term would still have one and only one meaning, but variations would prevent those meanings from limiting the claim terms.



Warning & Disclaimer: The pages, articles and comments on do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of

Join the Discussion

One comment so far.

  • [Avatar for Steve]
    August 26, 2014 09:34 pm

    Great advice.

    I would add that — especially important if not critical for independent inventors, small companies with few if any patents or applications, and pharma / bio firms — always have an active continuation on file at the patent office(s).

    That way you’ll always have the opportunity to obtain more (and potentially more clearly / strongly infringed) claims to protect your invention(s).

    In many of the cases Mr. Root provides, the inventor’s specifications would have supported new claims which could have overcome the noted deficiencies.