The Supreme Court has opened the door to a category of patent lawsuits that a lower court had barred, issuing a decision that will probably shift power in the courtroom from bigger patent-owning companies to smaller start-up companies that rely on obtaining licenses for patented technology. The court's 8-1 decision Tuesday held that the holder of a patent license can sue to challenge the patent's validity without first refusing to pay royalties and putting itself in breach of the license agreement.