Just when the Federal Circuit starts showing signs of (once again) making sense, they come up with a new decision that leaves me scratching my head. It’s no secret that the Doctrine of Equivalents is on their hit list. Unless I’m mistaken, the next patentee-friendly doctrine to go might be the ancient and honorable rule that “features of the preferred embodiment should not be read into patent claims.”

The general rules of claim construction are familiar and, for the most part, make sense. Words used in patent claims should be given their ordinary meaning unless the patentee makes clear he means something else. Limitations that do not appear in the claims should not be read into the claims absent compelling reasons to do so. The “preferred embodiment” described in the specification is just that, and even an inferior product can infringe so long as it meets the claim limitations, etc. No argument from me there.

In Irdeto Access the issue was the meaning of “group” – specifically whether a “group” of subscribers to a television broadcast service can include all the subscribers or must necessarily be limited to less than all the subscribers. Ordinarily, and as a matter of plain English, a “group” can and does include everyone in a set as well as less than everyone in the set. The Court even acknowledged as much. However, because the only embodiment described in the patent made use of “groups” made up of fewer than all the subscribers, the Court held that the claims were limited in this manner and did not cover a system wherein a “group” could be the entire set of subscribers.

In a somewhat roundabout way, the Court read a feature of the preferred embodiment into the claims despite its numerous proscriptions against doing so and despite its numerous decisions that the “plain meaning” of claim terms ordinarily controls.

In the Court’s defense, it did point to arguments made during prosecution wherein the patentee argued that, “We believe that the modifiers for key — “box”, “group” and “service” — are very adequately described in the specification and therefore there is a complete foundation for the use of these terms in the claims.” With some justification, the Court held that the patentee himself limited his claims to the disclosed embodiment by making this argument.

What’s unclear at this point is whether this case turns on its somewhat unique facts – namely the unusual argument made during prosecution – or whether this signals a broad shift toward finding claim limitations by innuendo and inadvertence rather than actual intent of the patentee. It’s probably too early to tell, but I’m slightly worried. As a practical matter, the doctrine of equivalents (despite the Supreme Court holding in Festo) is largely a thing of the past. Now even literal infringment may be vulnerable. The new rule, I fear, may be, “if it’s not expressly described in your specification, your claims don’t cover it.” Hope I’m wrong.

Sometime in the next six to twelve months, the Federal Circuit will render its en banc decision in Phillips v. AWH Corporation et al. a decision that most likely will have profound consequences for patent owners and those accused of infringement. Is the panel decision in Irdeto Access a sign of things to come? Or is it the last attempt to advance a terribly wrong policy that deserves an early death? Time will tell.