WEB PATENT NEWS--October, 2002

by Robert M. Hunter, Registered Patent Agent

News about patents, licensing and seed capital sources for inventors and innovating organizations.


I. THE NAME OF THE GAME IS CLAIMS - A recent court decision emphasizes the importance of the wording of patent claims.

II. AVOIDING INADVERTENT LOSS OF CLAIM BREADTH - A checklist to help you avoid claim-breadth-limiting pitfalls during preparation and prosecution of patent applications.

III. UNIVERSITY OF HAWAII BUSINESS PLAN COMPETITION - With at least one UH student on your team, you can compete for for $50,000 in cash prizes.


The U.S. Court of Appeals for the Federal Circuit (Federal Circuit) and U.S. Supreme Court have signaled to inventors the importance of the wording of claims in patents. This article discusses the implications of a recent significant court decision on this subject.

In Johnson & Johnston Assoc. v. R.E. Service, No. 99-1076, the Federal Circuit reasserted “the fundamental principle that claims define the scope of patent protection” and that “the claims made in the patent are the sole measure of the grant.” In this case, the claims in the patent specifically limited the substrate of the invention to “a sheet of aluminum” and “the aluminum sheet.” The specification of the patent, however, disclosed: “While aluminum is currently the preferred material for the substrate, other metals, such as stainless steel or nickel alloys may be used.” The Federal Circuit decided that, having disclosed, but not claimed the steel substrates, the patent holder could not later invoke the doctrine of equivalents to extend its aluminum limitation to encompass steel. Thus, the patent holder could not assert the doctrine of equivalents to cover the disclosed but unclaimed embodiments of the invention.

The Federal Circuit reminded inventors that “a patentee who inadvertently fails to claim disclosed subject matter, however, is not left without remedy. Within two years from the grant of the original patent, a patentee may file a reissue application and attempt to enlarge the scope of the original claims to include the disclosed but previously unclaimed subject matter. 35 U.S.C. § 251 (2000). In addition, a patentee can file a separate application claiming the disclosed subject matter under 35 U.S.C. § 120 (2000) (allowing filing as a continuation application if filed before all applications in the chain issue).”

This case emphasizes the importance of claiming all embodiments of an invention that are disclosed in a patent application, preferably in the application as filed, but at least before the final Office action is mailed. Disclosing without claiming an embodiment of an invention makes no sense because “what is not claimed is public property.” The Federal Circuit quoted this statement of the law by the Supreme Court from a case decided in the 1880’s: “The presumption is, and such is generally the fact, that what is not claimed was not invented by the patentee, but was known and used before he made his invention. But, whether so or not, his own act has made it public property if it was not so before. The patent itself, as soon as it is issued, is the evidence of this. The public has the undoubted right to use, and it is to be presumed does use, what is not specifically claimed in the patent.”


The wording of a patent claim (the limitations it recites) determines the potential extent of the intellectual property owned by the patentee. That potential claim breadth can be reduced by the actions of the patent applicant during preparation or prosecution of his/her patent application. Recent decisions by the U.S. Court of Appeals for the Federal Circuit (Federal Circuit) illustrate how limitations can be read into claims based on the actions of the patent applicant. This article presents a checklist for avoiding inadvertent erosion of claim breadth.

1. Avoid unqualified and limiting statements anywhere in the specification about what the invention is. If a statement in any way limits the breadth of potential claims, preface the statement with an open-ended phrase, such as “Preferably” or “In a preferred embodiment” or “In another embodiment.” This is important because statements about “the invention” or “all embodiments of the present invention” have been used by the Federal Circuit to limit claim coverage. In Wang Labs, Inc. v. America Online, Inc., No. 98-1363, the Federal Circuit concluded that “when the ‘preferred embodiment’ is described as the invention itself, the claims are not entitled to a broader scope than that embodiment.”

2. Avoid distinguishing the invention from the background art in the Background of the Invention section in ways that limit claim breadth. This is important because words used to describe elements and limitations in the background art may be used to exclude those elements in the claimed invention, unless the specification explicitly includes them. In Ekchian v. Home Depot, Inc., No. 96-1207, the Federal Circuit noted “since, by distinguishing the claimed invention over the prior art, an applicant is indicating what the claims do not cover, he is by implication surrendering such protection.”

3. Ensure that a description of the invention in the Summary of the Invention section mirrors the broadest claims. In Scimed Life Systems v. Advanced Cardiovascular Systems, No. 99-1499, the Federal Circuit stated “where the specification makes clear that the invention does not include a particular feature, that feature is deemed to be outside the reach of the claims of the patent, even though the language of the claims, read without reference to the specification, might be considered broad enough to encompass the feature in question.” Amend the summary during prosecution if necessary.

4. Avoid providing definitions of terms in the specification that narrow the breadth of claims that contain those terms. Terms can be defined explicitly (“The term . . . means . . . .”) and implicitly (by consistent usage) as the Federal Circuit found in O.I. Corp. v. Tekmar Co., No. 96-1427, when it held that “we conclude that one skilled in the art reading the claims, description, and prosecution history would conclude that the term “passage” in claim 17 does not encompass a smooth-walled, completely cylindrical structure.” Thus, the patentee could not prevent others from avoiding infringement by using "a smooth-walled, completely cylindrical structure" as a "passage."

5. While U.S. law requires only that the best mode (the best way of practicing the invention) be disclosed in a patent application, applicants are advised to disclose a range of alternative embodiments. In Unique Coupons v. Northfield, No. 00-1300 (unpublished), the applicant disclosed one embodiment of the invention, and the Federal Circuit held that all claims would “require” the limitations associated with that embodiment. It is wise to also ensure, however, that the specification cannot be interpreted to limit the invention to elements found in common among alternative embodiments or to exclude unintentionally omitted embodiments. Permissive language, such as “e.g.” or “may” can be used to advantage when describing alternative structures or steps. Note that under Festo Corp. v Shoketsu Kinzoku Kogyo Kabushiki decision of the Supreme Court, the approach of leaving embodiments out of the specification so that they can be recaptured under the doctrine of equivalents does not work. Under Festo, equivalents that are foreseeable by one having ordinary skill in the art are excluded from equivalent protection unless they are claimed. So, all foreseeable embodiments must be disclosed and claimed to be covered by a patent. As stated in Judge Rader’s concurring opinion in Johnson and Johnston v. R.E. Service, No. 99-1076, “the doctrine of equivalents does not capture subject matter that the patent drafter reasonably could have foreseen during the application process and included in the claims.”

6. Consider drafting some process claims in a “step plus function” format) e.g., by using the words “a step for” to begin the recitation of each process step. Similarly, consider drafting some product claims in a “means plus function” format) e.g., by using the words “means for” to begin the recitation of each element of the product. In Epcon Gas Sys. v. Bauer Compressors, No. 01-1043, these approaches have been deemed by the Federal Circuit to invoke the benefits of 35 U.S.C. 112. During prosecution, casting some narrowing amendments in a step- or means plus-function form should also be considered in light of the fact that Festo left Section 112 equivalents unchanged. A Section 112 equivalent is anything that represents “an insubstantial change which adds nothing of significance to the structure, material, or acts disclosed in the patent specification.” Thus, Section 112 equivalents may not be as broad as equivalents under the doctrine of equivalents, but they are still better than no equivalents at all.

7. Include in the Abstract of the Disclosure section a description of the invention that reflects the broadest independent claim. In Hill-Rom Co. v. Kinetic Concepts, Inc., No. 99-1314, the Federal Circuit interpreted the term “cushion” in the claims more narrowly, citing the way the term was used in the abstract by noting “the abstract states that ‘[t]he inflatable structure preferably has two components: a) lower inflatable layer which is selectively operable to provide basic support for the patient,’ and ‘a second inflatable layer includ[ing] a plurality of zones for establishing optimal patient interface pressures and patient comfort levels.’” Amend the abstract during prosecution if necessary.

8. During prosecution, do not argue that an element of the invention is necessary to the practice of a claimed invention unless you are willing to live with that limitation in enforcing your patent. An inventor can be deemed to have surrendered claim breadth by arguing during prosecution that a certain claimed element produces “unique results” or in some other way is “superior” or “inventive.” Similarly, an inventor who argues in his specification or during prosecution that an element is “critical” can be deemed to disclaim combinations that do not include the element.

9. Remember that delay during prosecution on the part of a patent applicant can affect patent coverage in a new way now – by reducing the length of time an issued patent is valid. To avoid a day-for-day reduction in patent term, file a complete reply within the response period specified in the Office action (typically three months). If the reply is filed on the last day of the response period, use Express Mail or fax because the “date of receipt” at the USPTO is used in calculating term reduction, not the date on the certificate of mailing.

While the courts have clearly pointed out that claims define what an invention is, the Federal Circuit has also pointed out that statements made in the specification of an issued patent and statements made during prosecution of a patent application can establish what the invention is not. Now, more than ever, care must be exercised by patent applicants to avoid taking actions that erode the breadth of patent claims.


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These programs are part of a series of Hawaii Technology Development Initiatives, which include a highly competitive package of tax incentives for technology companies doing business in the state.


Robert M. (Bob) Hunter, Ph.D.
Licensed Professional Engineer
Registered Patent Agent
65-1116 Hoku'ula Rd.
P.O. Box 2709
Kamuela, HI 96743
tel (808) 885-4194
fax (808) 885-4114
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