In the 1891 case of Ansonia Brass and Copper Company v. Electrical Supply Company, the U.S Supreme Court was tasked with determining whether a patent for an improvement on an existing invention could be considered valid if it did not significantly enhance or change the original product's functionality. The dispute arose when Ansonia Brass and Copper Co., who held a patent for electrical conductors used in lighting systems, sued Electrical Supply Co. for infringement based on their production of similar conductors that included minor modifications to improve durability. The court ruled in favor of Electrical Supply Co., stating that while patents can indeed be granted for improvements upon existing inventions, such enhancements must contribute substantially to its utility or efficacy. In this case, they found that the changes made by Electrical Supply were trivial and did not fundamentally alter how the conductor functioned; therefore, it didn't infringe upon Ansonia’s patent rights.

The dissenting opinion in the case of Ansonia Brass and Copper Company v. Electrical Supply Company argued that the patent at issue was not a new invention, but merely an improvement on existing technology. The justice believed that while it may have been more efficient or effective than previous designs, this did not qualify it as a novel creation deserving of its own patent protection. He contended that granting such broad patents could stifle innovation by preventing others from making their own improvements to the design. Furthermore, he expressed concern about potential monopolistic practices if companies were able to secure exclusive rights over basic technological concepts simply because they made minor modifications or enhancements to them.