The patent (https://patents.google.com/patent/US7892474B2/en) doesn’t seem to mention galvanometers at all.

It uses the phrase ”digital light processing/digital micromirror device”.

I don’t know how that slash should be interpreted. If it’s “aka”, the patent doesn’t cover using prisms.

I wouldn’t bet on that, though, noting that the patent is careful to avoid the term “light”, using the broader “electromagnetic radiation” instead.