The LCD resin printers I've looked at have pretty standard resolutions like for a smartphone and I understand they use the same technology. However, color LCD screens have three RGB sub-pixels for each color pixel. Check for example this magnified picture of an S-IPS LCD screen: It seems like they could just omit the color filter and have three grayscale pixels for each color pixel.
3D printing just uses one color - UV. So why don't they have resolutions that are multiples of three of the usual resolutions?
All results about sub-pixels that I could find are about anti-aliasing, which is different (using the existing pixels better vs. having more pixels).