Law on enablement requirement
A patent specification must enable one of ordinary skill in the art to make and use the full scope of the claimed invention without undue experimentation under 35 USC 112, first paragraph. Otherwise, such claim is invalid for failing to satisfy the enablement requirement. The enablement doctrine prevents both inadequate disclosure of an invention and overbroad claiming that might otherwise attempt to cover more than was actually invented.
Facts of Magsil v. Hitachi
In Magsil v. Hitachi (Fed. Cir. 2012), the patent claims were directed to computer hard disk drive storage systems. To manufacture disk drives, an adequate level of change in tunneling resistance is needed. Past efforts achieved a 2.7% change in resistance which was not sufficient for practical purposes. In contrast, the patent at issue achieved a 11.8% change in resistance. The patent specification attributed the increased % change to a decrease in surface roughness coupling two electrodes and insulator quality between the electrodes.
No upper limit to claimed range
The patent at issue used very broad language to claim the invention. In particular, the patent claimed any change in resistance by at least 10% at room temperature. The claims also utilized an open ended transitional phrase, namely, ‘comprising’. This style of claiming the invention defined the lower limit of the % resistance change but not an upper limit, thereby covering a resistance change of 120% and up to infinity. At the time of filing the patent application, the inventors were able to achieve an 11.8% resistance change. They also testified that at the time of filing, they inventors did not know how to achieve a 20% change in resistance, although they were able to achieve an 18% resistance change after filing. Since 1995 when the patent application was filed, industry has been able to achieve a resistance change of 600%.
Claims too broad and specification did not enable entire scope of claimed range
The patent owner is now asserting the patent against defendant manufacturing product within the upper ranges which the inventors were not able to achieve at the time of filing the patent application. The district court held that the patent claims to be invalid for failing to enable the full scope of the claimed invention. The Federal Circuit affirms.
Gillette patent claims
During litigation, the patent owner attempted to analogize the instant case to the Gillette patents related to the Mach 3 razor blades. In the Gillette patents, the claims used the open ended transitional phrase ‘comprising’ and required first, second and third groups of blades. The patent owner contended that this claim should also have been held invalid for not enabling the full scope of the claimed invention since it would have been impossible to make a working razor blade with an infinite number of blades. The Federal Circuit discounted the patent owners contentions in that the Gillette invention did not claim an infinite number of blades but blades with three separate categories of characteristics.
In contrast, the patent at issue enabled an ordinary skilled artisan to achieve a small subset (i.e., up to 20%) of the claimed range (i.e., 10% to infinity). The court stated that many additional inventions and advances were necessary to take this technology from a 20% resistance change to the over 600% change in present data storage systems.
Claim drafting tips
This case illustrates a few claim drafting pitfalls. Claimed ranges should be bounded with an upper and lower limit in the independent claims or at least in the dependent claims (i.e., fall back position). Moreover, it is important to carefully consider the range being claimed. For example, if drafting a patent application most applicable to a two (2) wheeled vehicle that can be applied to a four wheeled vehicle, then instead of claiming the vehicle as a vehicle having at least two wheels or a plurality of wheel, it may be worthwhile to recite a vehicle having one to four wheels. U.S. patent application allow three independent claims so that patent owners can layer the claims to test different claiming strategies.
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