The resulting uncertainty could cause some inventors to decide against patenting their technology, which would mean others couldn't license the technology to build on top of, he said.
Microsoft countered that "questionable patents that should never have been issued" stifle innovation.
"Responding in litigation to these bad patents imposes a tax on all innovative companies and ultimately on the consuming public," Andy Culbert, Microsoft associate general counsel, said in an e-mailed statement.
The company argues that i4i should never have been granted its patent in the first place. "Microsoft's solution to prevent this type of abuse is to have the courts apply the burden that generally applies in all civil cases - the 'preponderance of evidence' standard -- to prove a patent invalid," Culbert said.
A wide range of companies have lined up on each side of the case. Some make unusual bedfellows. Supporting Microsoft are Apple, Google and the Electronic Frontier Foundation.
Supporting i4i is a longer list, including 3M, Bayer, 19 venture capital firms, the U.S. government and six former commissioners or directors of the patent office.
"If you look at the group that filed amicus briefs, you can see pretty clearly the companies that filed on Microsoft's side tend to be companies who get a lot of lawsuits against them on patents, and in particular a lot of lawsuits against them by what we call nonpracticing entities," Columbia said. Often called "patent trolls," these companies buy up patents and then seek infringers they can pursue for royalties.
While big companies like Microsoft have their own patents to defend, they also get sued frequently, often by patent trolls. "They must be thinking they would rather have the standard lowered for these nonpracticing-entity cases," she said.
Pharmaceutical companies, such as Bayer, are hit less by nonpracticing entities and are more likely to assert their own patents, she said. "Big pharma really uses patents to keep away the [generic brands] so they don't want the standards lowered," she said.
The case dates back to 2007, when i4i sued Microsoft for allegedly infringing a patent covering a technology that lets users manipulate the architecture and content of a document. It said Microsoft infringed the patent by allowing Word users to create custom XML documents. In 2009, the U.S. District Court for the Eastern District of Texas found in i4i's favor and ordered Microsoft to stop selling Word products in the U.S. in their current form. Microsoft eventually removed the feature in order to continue selling the product.
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