Stereolithography was the first style of 3D printing I ever heard about, back in the late '80s. I can't tell from this article what it is about the machine they're profiling which is supposed to represent an improvement.
Traditional stereolithography is layer-based like FDM printers. Per the article, this solidifies the whole object all at once. If I understand it correctly, it does this by rotating the resin vat and controlling the UV light to expose the whole object evenly.
I think "into" is the new part as opposed to "onto".