well, you're allowed to patent and have proprietary rights to the contents of your graduate school research if they meet the criteria lol, in fact, that is a good idea for a student working on a novel technology.

If you work for a private firm, then they presumably own the rights to patents you develop while under their employment, depending on your contract. But also, you have access to patents and technologies through the corporate patent sharing agreements and licenses that you'd never have access to in the university system, so it can work both ways, where you may be able to develop things not possible in traditional academia, but whether you actually retain those rights is not as clear as in academia.