for converting or amplifying images in two or more colours

Full Title

Cathode ray tubes; Electron beam tubes (H01J25/00, H01J33/00, H01J35/00, H01J37/00 take precedence; details of cathode ray tubes or of electron beam tubes H01J29/00) > having a screen on or from which an image or pattern is formed, picked up, converted, or stored > Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output > for converting or amplifying images in two or more colours