I want to see the math for creating an electron gun that can blast phospors on a screen a foot away that is 70 inches wide and flat. That big space in most CRTs let the math be simple for how the electron gun emitted electrons. If the gun had a narrow angle to the screen (small screens or deeper backing), then the screen could be slightly curved and t just needed to be a grid coming out of the gun. To visualize this on imagine if you following the curve of CRT screens up and down then left and right, eventually it would make a sphere around the electron gun.
But towards the end of CRTs there were flat screens, not thin CRTs, but things that were clearly a CRT but with a non-curved screen. To make this happen the electron gun needed to perform a distortion on the scan lines that would account for this.
In theory the gun could be moved closer and closer to the screen and the math adjusted to be correct at any distance. But the further towards the edge of the screen a pixel was the more precise the gun would need to be to hit the right spot and the fewed trick filters and gratings on the screen itself could do. Clearly 70 inches inches practical for an in home CRT, but I think it is fun to think about.
