Abstract: Measuring apparatus for measuring the position of a light source inside a lighthouse as used in the manufacture of phosphor screens of color picture tubes comprises a base plate and two optical projection devices which are directed on to the light source, and which each contain at least two position diodes. An evaluating circuit connected thereto ascertains the position of the light source and the result is fed to a display device.

Abstract: Heretofore, the tube neck, the seal edge extending along the largest circumference of the funnel section, and reference pads located at or near the seal edge have been aligned relative to each other. It is proposed to align the seal edge, the reference pads, and the tube neck in relation to the longitudinal axis of a "transition section" (portion between neck-funnel seal and position of deflection on the funnel yoke) in such a way that the axis perpendicular to the plane bounded by the seal edge and the reference pads, the longitudinal axis of the neck coincide with the longitudinal axis of the "transition section".

Abstract: An optical adjusting method and apparatus for aligning the electron gun system in color television picture tubes during the sealing process. The electron gun system and the picture tube prior to assembly are separated from each other with the electron gun system being supported for rotation about its longitudinal axis and having optically effective position marks which may comprise slots or columns thereon for aligning the electron gun system in a predetermined alignment. A light beam traverses the position marks which, in the electron gun system, when properly rotated, coincides with the axis between a light source and a light intensity measuring means such that the electron gun system is aligned in its predetermined alignment when a maximum light intensity with respect to a predetermined threshold is detected.