The Reflected-Beam Kinescope

The reflected-beam kinescope is a short tube particularly suited for picture sizes of 21 inches or more. It retains the conventional gun and external deflection components and is axially symmetric. Although the effective deflection angle is nearly 180°, the deflection power required is equivalent to that used in conventional 90° kinescopes. The electron beam scans through an apertured phosphor screen and is reflected back to the screen by the faceplate. The screen attenuates the beam by a factor of 4, except in the case of a radial scan where a cutout in the center of the screen may be made to permit free passage of the beam. The results of a theoretical and experimental study of the tube are presented. They show the raster to be inherently barrel-distorted. However, the distortion may be corrected in several ways. The resolution is somewhat lower than in standard tubes, although it is considered to be adequate. High detail contrast is obtained.