Build Your Own SLA/SLS

I saw this video while looking around and researching for my future build, https://www.youtube.com/watch?v=MS1t3tHsx9k
and I was wondering why you "have" to use a projector? Wouldn't an LCD flush mounted to the resin container with UV backlighting work? https://www.youtube.com/watch?v=op00xgiD7sc similar to that process?

No, LCD will not pass any UV light, it blocks all light below 400nm.

LCD can be used in 3d printing but with near uv sensitive resin, which most are. I am building an LCD printer with 410nm LED array, a simple backlight will not have enough power, you will lose 90% of the light as is passes through the LCD.

Its also not a simple task to build one of these machines, ive been working on this project for over a year and nearing completion of the first working prototype.