The U.S. Supreme Court declined to hear Microsoft Corp's appeal in a case that could have reshaped the standards used in court fights to determine if patents have been infringed.
Lower courts had found that the date-picker tool in Microsoft's Outlook calendar infringed a patent held by French telecommunications equipment maker Alcatel-Lucent. The companies have an unresolved fight over damages.
In its appeal, Microsoft argued that a patent could be held invalid if evidence is presented in a court case that was not available at the time the patent was granted. It also said that the standard for invalidating a patent should be a "preponderance" of evidence, rather than "clear and convincing" evidence.