A recent summary judgment opinion by Judge Patti B. Saris highlights the importance of expert testimony in substantiating factual disputes and withstanding summary judgment. In denying both parties’ motions for summary judgment on infringement, Judge Saris relied heavily on the opposing opinions of the parties’ experts.

Here, Boston University sued Everlight Electronics, a manufacturer of light-emitting diodes, or LEDs, for infringement of U.S. Patent No. 5,686,738, which covers a method for preparing certain types of gallium nitride films. Everlight’s products undisputedly contained gallium nitride films that were crystalline in structure.

The parties’ primary dispute centered around whether those gallium nitride films were either monocrystalline in structure, or a mixture of amorphous and polycrystalline structures. Using a number of different scientific methodologies, BU’s expert found that the structures were polycrystalline or amorphous. His analysis rested largely on the presence of tiny separations between individual crystals, called “grain boundaries.” Everlight’s expert, largely relying on similar methods, contended that these “grain boundaries” were not in fact indicative of polycrystalline structure, but rather were simply indications of flaws in the product’s monocrystalline structure.

Judge Saris, on the basis of these conflicting expert opinions as to a critical fact, denied summary judgment, leaving the dispute for a jury to decide.

The case is Trustees of Boston University v. Everlight Electronics Co., Ltd., et al., No. 12-11935-PBS, in the District of Massachusetts.