Avoiding a Jury Trial on the Issue of Infringement Under the Doctrine of Equivalents


Under the doctrine of equivalents, a U.S. patent may be infringed by a product or process that is not identical to the patented invention, so long as the product or process and the patented invention exhibit a sufficient degree of similarity. In a patent infringement trial conducted before a jury, the issue of infringement under the doctrine of equivalents is decided by the jury, not by the judge. The jury may decide that there is (or is not) infringement under the doctrine of equivalents without fully explaining the reasons for its decision. On appeal, it may be very difficult to reverse such a jury decision.

Consequently, a fundamental objective of many alleged infringers in U.S. patent litigation is to prevent the issue of infringement by equivalents from ever reaching the jury. One technique for accomplishing this objective is to request that the issue of infringement by equivalents be decided by the judge prior to the time of trial. This may be achieved by filing a so-called "motion for summary judgment", in which the alleged infringer attempts to persuade the judge that there is no need for a trial on the issue of equivalency because the relevant facts are undisputed and a proper application of the law of equivalency to the undisputed facts compels a conclusion of non-infringement.

The parties involved in U.S. patent litigation must therefore frequently evaluate the following important strategic questions: Under what circumstances may an alleged infringer successfully use a motion for summary judgment to avoid a jury trial on the issue of infringement under the doctrine of equivalents? More specifically, how and when may an alleged infringer successfully establish that, as a matter of law, an accused product is not equivalent to a claimed invention?

Some answers to these basic questions were provided by the recent decision of the U.S. Court of Appeals for the Federal Circuit ("the CAFC") in the case of Sage Products, Inc. v. Devon Industries, Inc. A detailed discussion of the Sage Products case and the CAFC's decision is provided below. This is followed by a description of some of the issues which companies should now consider when evaluating the potential risks of a jury trial on the issue of infringement under the doctrine of equivalents.

NON-INFRINGEMENT UNDER THE DOCTRINE OF EQUIVALENTS MAY BE DETERMINED AS A MATTER OF LAW

The Sage Products case involved two patents directed to containers for disposing of hazardous medical waste, such as hypodermic needles. The first patent was directed to a disposal container that allowed a user to deposit hazardous medical waste without touching waste already in the container. The container had an elongated slot at its top to allow entry of waste materials into the container. Barriers above and below the slot restricted access to the interior of the container. The patent's sole independent claim recited: A disposal container comprising... an elongated slot at the top of the container body for permitting access to the interior of the container body... [and] barrier means disposed adjacent said slot for restricting access to the interior of said container body... [the barrier means] comprising a first constriction extending over said slot, and... a complementary second constriction extending beneath said slot...

On the parties' cross-motions for summary judgment, the trial court held that the patent was not infringed, either literally or under the doctrine of equivalents. The trial court entered judgment for the alleged infringer, and the patentee appealed.

On appeal, the CAFC found that the claim language "the top of the container body" was properly interpreted as meaning the highest point of the container body, and the claim language "extending over said slot" was properly interpreted as requiring that the first constriction must be "above" the elongated slot. The ordinary meaning of these phrases controlled, since the patent and prosecution history indicated no intent by the patentee to deviate from the ordinary meaning.

The CAFC found that the element in the accused device which the patentee identified as corresponding to the "elongated slot" of the claimed invention was not located "at the top of the container body." This deficiency prevented literal infringement, and the CAFC concluded that the trial court had properly granted summary judgment of no literal infringement.

The patentee asserted that there were four different theories upon which a jury could have found infringement under the doctrine of equivalents. The CAFC concluded that each of these theories suffered from one of two alternative problems. Either: (1) the element in the accused device which allegedly corresponded to the elongated slot was not substantially "at the top of the container body", or (2) there was no first constriction in the accused device that extended substantially "over said slot." According to the CAFC, the patentee failed to present any theory of infringement under the doctrine of equivalents that simultaneously satisfied an insubstantial variation of both of these limitations.

The patentee argued that for purposes of infringement by equivalents, having two constrictions below the top of the container (as in the accused device) was the same as having one constriction above and one constriction below. According to the patentee, the claimed and accused arrangements accomplished substantially the same function, in substantially the same way, to achieve substantially the same result.

The CAFC disagreed, stating that the doctrine of equivalents did not allow the patentee to entirely remove the "top of the container" and "over said slot" limitations from the claim. The CAFC observed that if the doctrine of equivalents is applied too broadly, then the doctrine conflicts with the primary importance of the claims in defining the scope of a patentee's exclusive rights. Consequently, if a patentee claims an invention narrowly, then in many cases there may be no infringement under the doctrine of equivalents, even though the patentee might have been able to claim the invention more broadly. A contrary rule would have the effect of removing from the claims meaningful structural limitations on which the public should be able to rely.

The CAFC then explained why, in Sage Products, non-infringement under the doctrine of equivalents could be established as a matter of law without further fact finding, whereas in some other cases further fact finding might be required. First, the CAFC pointed out that the claimed invention in Sage Products was a relatively simple structural device. Second, the CAFC found that a skilled claim drafter would have foreseen the limiting potential of requiring the first constriction to be "over said slot". More specifically, at the time this limitation was incorporated into the claim, the significance of the limitation was not obscured by any subtlety of language, or technological complexity, or any subsequent change in the state of the art (such as later-developed technology).

The CAFC commented that if the patentee had desired broad patent protection for a container that performed a function similar (but not identical) to the claimed container, then the patentee could have sought claims with fewer structural limitations. During prosecution, the patentee had an opportunity to negotiate broader claims, but the patentee failed to do so. Instead, the patentee prosecuted and obtained a patent containing clearly limited claims, which the patentee then later sought to expand during litigation by using the doctrine of equivalents. The CAFC concluded that the patentee, rather than the public, should bear the cost of the patentee's failure to seek protection for a foreseeable alteration of the claimed structure.

The CAFC acknowledged that placing on the patentee the burden of seeking protection for the foreseeable variations of a claim element tended to make patent prosecution more expensive. The CAFC pointed out, however, that the alternative rule -- which would allow the doctrine of equivalents to encompass foreseeable variations of a claim element -- would also lead to higher costs. Such higher costs would be born by the public, in the form of foreclosed competitive activity in areas near, but not within, the literal scope of each issued patent claim. The CAFC observed that the doctrine of equivalents blurs the line of distinction between infringing and non-infringing activity. The doctrine creates a zone of uncertainty, in which competitors operate at greater risk. The choice, therefore, is between imposing the higher cost of careful prosecution on the patentee, or imposing the higher cost of foreclosed competitive activity on the public. Given this choice, the CAFC concluded that the higher cost was appropriately imposed upon the patentee, who is best positioned to determine whether or not a particular invention warrants investment at a higher level.

On appeal, the patentee also presented the CAFC with an infringement argument based upon a new claim interpretation which had not been presented to the trial court. The CAFC refused to consider this new claim interpretation for the first time on appeal. Although claim interpretation is a matter of law, and the interpretation given to claims by a trial court is reviewed anew by the CAFC on appeal, the CAFC emphasized that its role is to review decisions reached by a trial court, including decisions regarding claim interpretation. The CAFC stated that its role is not to "review" matters of claim interpretation that have not first been presented to the trial court.

In summary, the CAFC determined that the claim defined a precise arrangement of structural elements that cooperated in a particular way to achieve a certain result. The accused device achieved a similar result, but did so by a different arrangement of elements. Because the claim contained clear structural limitations, the CAFC concluded that the public had a right to rely on those clear structural limitations in conducting its business activities. The CAFC refused to effectively remove such clear structural claim limitations under the doctrine of equivalents. Accordingly, the CAFC affirmed the trial court's summary judgment of non-infringement.

NON-INFRINGEMENT UNDER THE DOCTRINE OF EQUIVALENTS OF A MEANS-PLUS-FUNCTION ELEMENT MAY BE DETERMINED AS A MATTER OF LAW

The second patent in Sage Products was directed to a needle removal and disposal device. The device included a storage container with a cap. The cap had a slot which was notched so that it grasped the hub of a syringe needle and allowed the user to unscrew the needle without touching it. The claimed device also included "closure means" that controlled access to the slot. Two different embodiments of the closure means were disclosed. The patent contained two independent claims, which recited: A needle removal and disposal device for detaching single or double-ended sampling needles which are thread engaged to a syringe body and storing detached sampling needles, said device comprising: storage container means; cap means associated with said storage container means, said cap means having a plate means with slot means opening therethrough, said slot means including integral wall means depending into said storage container means, entry port means and a plurality of stepped notches each having a different gap dimension for accommodating different sized needle hub portions; and closure means pivotably associated with said plate means and being movable with respect to said slot means for controlling access thereto; wherein said device is capable of engaging a sampling needle hub portion at a stepped notch whereby a syringe thread-engaged to a hub portion may be rotated with respect to the hub portion for detachment of a sampling needle, whereby detached needles and hub portions may be deposited through said entry port means into said storage container means, said device providing said storage container means for accumulation of sampling needles subsequent to detachment from syringes, and whereby said pivotable closure means is capable of moving to close access to said slot means and provide safe storage of sampling needles within said storage container means. (emphasis added)

A needle removal and disposal device for use with single or double-ended sampling needles having hub portions thread-engaging a syringe at the hub portion, said device comprising: cap means having a plate means with slot means opening therethrough, said slot means including entry port means and a plurality of stepped notches, each notch having a different notch gap dimension permitting engagement with different sized needle hub portions, said slot means further including depending wall means integral with said plate means, movable closure means pivotably associating with said cap means at pivot means thereof, said movable closure means being selectively movable between an open access and closed access position with respect to said slot means, storage container means, associating with said cap means, said slot means opening to said storage container means, and said wall means depending into said storage container means, wherein said device facilitates detaching a sampling needle from a syringe by engagement of a needle hub portion at a stepped notch and rotation of the syringe with respect to said sampling needle hub portion, whereby a detached sampling needle and associated hub portion may be deposited through said entry port means for storage within said storage container means therebelow. (emphasis added)

The accused product had a hinged lid that could be left open or, alternatively, placed in a closed position. However, once closed, the lid of the accused product locked in place and did not reopen.

On the parties' cross-motions for summary judgment, the trial court held that the patent was not infringed, either literally or by equivalents. The trial court entered judgment for the alleged infringer, and the patentee appealed.

On appeal, the fundamental issue with respect to literal infringement was whether the claims required the "closure means" to move freely from a closed position to an open position. In other words, the issue with respect to literal infringement was whether the claims required a lid that was reopenable, or whether the claims encompassed a lid which locked shut (as in the accused product).

The parties first disputed whether the "closure means" in each claim was a means-plus-function element requiring interpretation under 35 U.S.C. '112, 6 6. Because the word "means" was used in the claims, a presumption existed that the patentee had intended to define the "closure means" element as a means-plus-function element. The CAFC pointed out, however, that this presumption was not conclusive. For example, a claim using the word "means" does not define a means-plus-function element if the claim: (1) uses the word "means" but fails to specify a corresponding function for the "means" to perform, or (2) recites a function, but then also recites sufficient structure, material, or acts within the claim itself to perform entirely the recited function.

The CAFC found that both claims 1 and 10 specified a corresponding function for the claimed "closure means" to perform. In particular, the CAFC found that both claims 1 and 10 specified that the closure means must perform the function of closing the slot means. Both claims also required that the closure means must perform at least one additional function. In the case of claim 1, the additional function performed by the closure means was "controlling access" to the slot. In the case of claim 10, the additional function performed by the closure means was "being selectively movable between an open access and closed access position". Neither claim explicitly recited the structure, material, or acts needed to perform these functions. The CAFC therefore concluded that the "closure means" in each claim was a means-plus-function element requiring interpretation under '112, 6 6.

Accordingly, the "closure means" was properly construed by looking to the patent specification and interpreting the claim language in light of the corresponding structure, material, or acts disclosed in the specification and equivalents thereof. The CAFC found that the patent specification clearly identified two embodiments of a structure which performed the claimed function of closing the slot means. Both of the disclosed embodiments were reopenable, and both embodiments allowed the user to freely move the structure between the closed and open positions.

The CAFC noted that the claims themselves contained explicit functional recitations that required the closure means to be reopenable. Specifically, claim 1 required that the closure means must perform the function of "controlling access" to the slot means. Claim 10 required that the movable closure means must be "selectively movable between an open access and closed access position with respect to said slot means." The CAFC stated that to be an equivalent of these disclosed means under '112, 6 6, the accused structure must perform the functions explicitly recited in the claims.

The CAFC further pointed out that the correctness of interpreting the claims as defining a reopenable closure means could be confirmed by reviewing the additional intrinsic evidence relating to claim interpretation. The written description expressly described the importance of a closure means that was reopenable. The prosecution history indicated that the patentee had distinguished the claimed invention by the absence from the prior art of a pivotable closure for granting or denying access to the slot means.

The CAFC concluded that the claims required a closure means that moved freely between a closed position and an open position, to control access to the slot means. The accused device had a lid that locked closed and could not be moved back from a closed position to an open position. Under the CAFC's claim interpretation, the accused lid did not fall within the literal scope of the claims. The CAFC concluded that the trial court had properly granted summary judgment of no literal infringement.

The patentee argued that, under the doctrine of equivalents, the permanently locking lid of the accused product was equivalent to the reopenable lid defined by the patent claims.

The CAFC disagreed. The CAFC acknowledged that by defining the "closure means" using means-plus-function terminology, the patentee had indicated some degree of flexibility regarding the type of structure that would be adequate to perform the "closing" function. If the patentee had imposed no further limitations upon the functions to be performed by that structure, then the CAFC might have reached a different conclusion about the permissible scope of equivalents. However, the claims recited additional functional restrictions on the closure means. In the case of claim 1, the claim recited that the "closure means" must perform the function of "controlling access" to the slot means. In the case of claim 10, the claim recited that the "closure means" must perform the function of "being selectively movable between an open access and a closed access position". The written description also indicated that "movement to closed and open positions" was a critical restriction on the structure, material, or acts that could be used as a "closure means."

The CAFC stated that these additional functional limitations on the closure means, which were disclosed in the written description and expressly recited in the claims, narrowed the function-way-result analysis for purposes of the doctrine of equivalents. According to the CAFC, an accused element cannot perform substantially the same function, in substantially the same way, to achieve substantially the same result as the claimed element if the accused element does not perform at least a function equivalent to that expressly recited in the claimed element.

The claims explicitly required the closure means to perform certain functions. The element in the accused product which allegedly corresponded to the claimed closure means did not perform a function equivalent to those expressly recited in the claim. The differences between the claimed invention and the accused product could be considered "insubstantial" only if the additional functional claim limitations on the closure means were completely ignored. However, the doctrine of equivalents does not permit a patentee to effectively remove explicit functional limitations which are recited in the claims. If a claim recites that an element performs a specific function, and the written description reiterates the importance of that particular function, then an accused device which lacks that functionality is not an equivalent.

Since all of the functional requirements of the claimed "closure means" were not met by the accused device, there was no infringement under the doctrine of equivalents. Accordingly, the CAFC affirmed the trial court's summary judgment of non-infringement.

CONCLUSION

The CAFC's decision in the Sage Products case provides important guidance about claim interpretation, the doctrine of equivalents, and the circumstance under which non-infringement by equivalents may be determined as a matter of law. Companies attempting to evaluate the circumstances under which an alleged infringer may successfully use a motion for summary judgment to establish non-infringement under the doctrine of equivalents are well advised to study the Sage Products case and carefully consider the following guidelines:

  1. The foreseeable alterations of a relatively simple structural invention which the patentee fails to protect during prosecution are not protectable under the doctrine of equivalents. Consequently, during prosecution, applicants seeking the broadest possible scope of patent protection for simple structural inventions must draft claims which literally encompass all foreseeable variations of the invention. For similar reasons, during litigation an alleged infringer may establish non-infringement under the doctrine of equivalents as a matter of law where: (a) the claimed invention is a relatively simple structural device, and (b) the patentee asserts equivalence with respect to a claim limitation having a limiting potential that would have been apparent to a skilled claim drafter at the time the limitation was incorporated into the claim.
  2. If a patent claim recites that an element of the claim performs a specific function, and the written description reiterates the importance of that particular function, then an accused device lacking that functionality is not an equivalent. Consequently, an alleged infringer may establish non-infringement of a "means-plus-function" claim element under the doctrine of equivalents as a matter of law where the accused device fails to meet all of the explicit functional requirements of the claimed "means."
  3. To establish infringement under the doctrine of equivalents, the patentee must establish that the accused device simultaneously meets an insubstantial variation of all claim limitations that are not met literally. In other words, the patentee's theory of infringement by equivalents must be internally consistent. An alleged infringer may establish non-infringement under the doctrine of equivalents as a matter of law where the patentee's infringement theory of "insubstantial differences" with respect to one claim element would necessarily create a substantial difference with respect to another claim element.
  4. Use of the word "means" in a claim establishes a presumption that the patentee intended to define a "means-plus-function" element. However, a claim using the word "means" does not define a means-plus-function element if the claim: (a) uses the word "means" but fails to specify a corresponding function performed by the "means", or (b) recites a function, but then also recites sufficient structure, material, or acts within the claim itself to perform entirely the recited function.
  5. Although claim interpretation is a matter of law which the CAFC reviews anew on appeal, the CAFC may decline to review a claim interpretation which has not first been presented to the trial court.

Consideration of the guidelines used by the CAFC in the Sage Products case and expressed in this article should assist companies in evaluating the potential risks of a jury trial on the issue of infringement under the doctrine of equivalents.