Sony's arguments at the hearing attempt to highlight its position that the errors of fact regarding a preexisting licensing agreement and prior art document "could have" changed the outcome of the trial had the errors been corrected, and Sony should thus be entitled to a new trial. Sony argued that it was never afforded a chance to determine whether the error was significant or not, because it never knew about a piece of "hidden" prior art. The court questioned the impact of any error on the ability of Sony to litigate the case fairly, and appears hesitant to second-guess the district court judge who witnessed the entire trial and made a judgment call based on information gathered over the course of time during the litigation.
Immersion countered that any error was immaterial and insignificant, implying that such error should not warrant a new trial. Immersion's counsel also pointed out how little significance the "hidden" prior art document played during trial (e.g., zero references to it by Sony's primary invalidity expert, zero references to it by Sony in closing arguments, etc.). The court questioned the basis for such a conclusion, because how could the hidden piece of prior art play a prominent role at trial when Sony didn't know about it?
While I personally found Sony's arguments to verge on a last ditch effort of a 5 year old whining to a parent "it's not fair," and Immersion's counsel came across a little overconfident (perhaps better prepared?), you never know how the court will rule.
It will likely be months before the court hands down its decision.