Manchester v. Ericsson was a United States Supreme Court case that addressed the issue of patent infringement. The plaintiff, Manchester, had patented a machine for making screws and claimed that the defendant, Ericsson, had infringed upon his patent by making a similar machine. The Supreme Court held that Ericsson had not infringed upon Manchester's patent because the two machines were not substantially similar. The Court reasoned that the two machines were not substantially similar because they had different parts and operated differently. The Court noted that the two machines had different parts and that the parts were arranged differently. Furthermore, the Court noted that the two machines operated differently, as Manchester's machine used a cam to move the cutting tool while Ericsson's machine used a lever. The Court concluded that the two machines were not substantially similar and that Ericsson had not infringed upon Manchester's patent. The Court held that Ericsson was not liable for patent infringement and that Manchester was not entitled to damages.

Justice Field delivered the dissenting opinion in Manchester v. Ericsson, arguing that the patentee should be allowed to recover damages for infringement of their invention even if it was not novel or useful at the time of its issuance. He argued that Congress had intended to protect inventors from such infringements and thus a patentee should have exclusive rights regardless of whether their invention was actually new or improved upon existing technology. Furthermore, he argued that allowing an inventor to receive compensation for infringing patents would encourage innovation by providing incentives for inventors to create new products and inventions without fear of being sued by competitors who may have already created similar products prior to them. Ultimately, Justice Field concluded that denying a patent holder recovery due solely on grounds of novelty or usefulness would discourage innovation and undermine congressional intent when enacting laws protecting intellectual property rights.