There is a presumption of validity which attaches to the grant of a patent. This presumption is strengthened in a case where the prior art relied upon to invalidate the patent was considered and rejected by the patent office due to a unique combination of the essential elements of the device.
A patent owner sued a retailer and manufacturer alleging infringement of a patent covering windshield wipers. As a defense, the retailer and manufacturer claimed that the three essential elements disclosed in the patent claims were old in the art. The trial court found that, even though each element alone may have been old in the art, the prior art did not disclose the unique combination of the elements of plaintiff's patent. The case was appealed to the United States Court of Appeals for the Seventh Circuit.
Was there a patent infringement?
The Court held that the trial court's findings that the prior art did not disclose the unique combination of elements found in plaintiff's device, that the claims of plaintiff's patent described those elements, and that plaintiff's device was not an obvious or expected improvement over the prior art were supported by substantial evidence.