The Appeals Court for the Federal Circuit, which handles all patent-related appeals in the US, has just revived one of Apple's patent claims that could block sales of Samsung's Galaxy Tab 10.1. While upholding the lower court's other rulings in favor of Samsung, the appellate court did reverse a portion the district court's decision from December, which held that a prototype 1990s Knight Ridder device invalidated Apple's design patent — D504,889 — on the iPad. The lower court had denied Apple's request for a preliminary injunction against the Samsung Galaxy Tab 10.1 based on this perceived invalidity, and Samsung was able to continue selling the tablet in the US. With today's decision by the appeals court, Apple's infringement claims against the Galaxy Tab 10.1 are certainly strengthened, but it's unclear just how much value that will really add to its case in the end.

"We hold that the court erred in its analysis of the validity issue."

In comparing the Knight Ridder device to the iPad design patent, the appeals court noted "substantial differences in the overall visual appearance" of the devices, including the fact that the Ridder tablet had a wider and asymmetrical bezel design, and a screen that failed to match the iPad's look of an "unbroken slab of glass extending from edge to edge on the front side of the tablet." The court provided the following visual comparison (the Knight Ridder tablet is referred to as the "1994 Fidler," after the inventor's name):