OPTICAL SYSTEM FOR PROJECTION TV

摘要

An optical system comprises a fluorescent face constituting the tube face of the receiver tube which has a nonspherical shape to compensate for the curve of the image face of the projected picture on the screen. It also comprises four lenses arranged from the screen side to the tube face of the picture tube. The first lens has relatively weak power (reciprocal of focal distance) and a nonspherical shape in at least at one face. The second lens has relatively strong positive power. The third lens has relatively weak power and a nonspherical shape at least at one face.