Patent prosecution (writing patents) requires you pass the US patent bar, which is different from a state bar. To sit for the patent bar, you must have an engineering/science degree. Patent litigation, however, only requires you be certified by the bar of the state in which you are practicing; Patent Bar and technical degrees are not required.
You can also take the patent bar w/o going to law school, and become a patent agent. Still need the technical background, though.