This is a cautionary tale about choosing broad claim language at the peril of losing any claim that cannot be enabled across its full scope of coverage. In general, I think it highlights the problems associated with claims that attempt to directly recite the result to be achieved (e.g., a change in resistance of at least 10%), rather than the underlying advancements that bring about the improvements. The court noted specifically that the specification attributes the improved performance to smoother layers and an improved insulator, but “[t]he asserted claims, however, do not include the process steps of fabricating the device and require neither smoother layers nor a specifically improved insulator.” It also highlights the value of well thought out dependent claims, which could have easily narrowed the range in controversy to sufficiently enabled values, kept the patent alive, and avoided hundreds of thousands of dollars in litigation expenses.
Background / Facts: The patent at issue is directed to “tri-layer tunnel junction” read-write sensors for computer hard disk drive storage systems, whose resistance changes with a change in magnetization direction. The asserted claims broadly claim any tri-layer tunnel junction device wherein “applying a small magnitude of electromagnetic energy to the junction … causes a change in the resistance by at least 10% at room temperature,” which was an improvement over the previously achieved 2.7% change in resistance. However, while the asserted claims purported to cover resistive changes from 10% up to infinity, the specification only disclosed enough information to achieve an 11.8% resistive change.
Issue(s): Whether the asserted claims are invalid as a matter of law for lack of enablement through the full scope of the claimed invention.
Holding(s): Yes. To be enabling, the specification of a patent must teach those skilled in the art how to make and use the full scope of the claimed invention without undue experimentation. The patent specification in this case only enabled an ordinarily skilled artisan to achieve a small subset of the claimed range. The record contains no showing that the knowledge of that artisan would permit, at the time of filing, achievement of even a 20% resistive change let alone the modern values above 600% without undue experimentation, indeed without the nearly twelve years of experimentation necessary to actually reach those values. The open claim language chosen by the inventors did not grant them any forgiveness on the scope of required enablement.