Too Broad

Submitted by patentadmin on Mon, 03/07/2011 - 21:47

As anyone who has read our informative yet witty book, Essentials Of Intellectual Property, should be aware, broad patent claims are good. However, claims which are too broad are not good. (MagSil Corp. et al. v. Seagate Technology, et al.)

MagSil sued Seagate, and a host of others, for infringement of a patent directed to a “junction,” which is a multi-layered device consisting of at least two thin electrodes separated by a thin layer of insulation. Several of the defendants, including Seagate, Western Digital and Samsung, chose to settle and take licenses under the patent-in-suit. Hitachi, apparently made of sterner stuff, chose to fight and moved for summary judgment on the grounds, inter alia, that the patent claims were lacking a sufficient written description and were insufficiently enabled.

Claim 1 of the patent recited, “a device forming a junction … wherein applying a small magnitude of electromagnetic energy to the junction … causes a change in the resistance by at least 10% at room temperature.”

The patent specification disclosed that inventors’ research had “consistently” produced junctions with a 10% change in resistance and that they had observed resistance changes of “as much as 11.8%” at room temperature. Hitachi argued, and the court agreed, that the asserted claims read on any junction capable of generating a resistive change of “at least” 10% at room temperature, regardless of the method used to construct the junction or the materials from which it was made.

As noted by the court, a change of “at least” 10% encompassed a change of 1,000% and, indeed, an “infinite” change. Yet, the patent specification revealed that the best efforts of the inventors yielded a maximum resistance change of only 11.8% at room temperature. When asked whether, at the time the patent application was filed, he knew how to construct a junction generating more than a 20% change in resistance, one of the named inventors replied, “No, I certainly did not.”

Motion granted. “The scope of the claims must be less than or equal to the scope of the enablement … [and] 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 specification of the patent-in-suit, however, disclosed that the inventors’ “best efforts” yielded a maximum resistance change of only 11.8% at room temperature. Thus, “the undisputed facts … compel the conclusion that plaintiffs did not enable the full scope of the asserted claims without undue experimentation.”

THE LESSON TO BE LEARNED: Be careful when drafting patent claims; don’t claim more than the patent specification enables.

Add new comment