In an opinion addressing enablement under 35 USC 112, the US Court of Appeals for the Federal Circuit concluded that an asserted claim was invalid because the specification failed to enable its full scope, even though enablement as to the majority of claimed embodiments was undisputed. Trustees of Boston University v. Everlight Elecs. Co., Ltd., Case Nos. 16-2576, -2577, -2578, -2579, -2580, -2581, -2582, -2591, -2592, -2593, -2594, -2595 (Fed. Cir. July 25, 2018) (Prost, CJ).

Boston University (BU) sued Everlight for infringement of a patent directed to the preparation of monocrystalline gallium nitride (GaN) films via molecular beam epitaxy. The patent teaches providing a buffer layer between the desired GaN film and a substrate to prevent defects arising from a lattice mismatch between the GaN film and the substrate. During claim construction, the district court construed “a non-single crystalline buffer layer” to mean a layer of material that is either polycrystalline, amorphous, or a mixture of polycrystalline and amorphous. After a jury determined that Everlight infringed and had not proven the asserted claim’s invalidity, Everlight renewed its petition for judgment as a matter of law that the claim was invalid for lack of enablement, and the district court denied the motion. Everlight appealed.  

Before the Federal Circuit, Everlight argued that the asserted claim was invalid because the specification does not teach one of skill in the art how to grow the monocrystalline GaN film directly on an amorphous buffer layer. At trial, Everlight’s expert testified that such an arrangement was impossible, and BU’s expert agreed. BU responded that others had grown monocrystalline GaN film directly on an amorphous buffer layer, so such an arrangement was not impossible. However, the Federal Circuit explained that the question presented was not whether the arrangement was possible, but whether the specification teaches one of skill in the art how to make the claimed device as of the patent’s effective filing date. 

BU argued that the disclosure was sufficient because there was no dispute as to the enablement of five out of six permutations. The Federal Circuit disagreed, explaining that the specification must enable the full scope of the claims. While an artisan’s knowledge of the prior art and routine experimentation can fill small gaps, one of the claimed embodiments here required undue experimentation. The Court further noted that for purposes of infringement, BU had sought a construction that included the amorphous layer. Since BU wanted to exclude others from practicing what it regarded as its invention, the enablement requirement demanded that its patent teach the public how to make and use that invention.

Practice Note: Patentees should exercise caution when seeking a broad construction where the desired construction may ensnare embodiments not contemplated in the specification.