Electrostatic printing of phosphor screens of color picture tubes

A new technique for printing phosphor screens of color picture tubes has been developed which has many advantages over the traditional phosphor printing methods. The technique consists of producing a beam of charged phosphor particles and causing the beam of particles to follow the same trajectories to the screen as those which the electrons will subsequently follow in the completed tube. This is possible because the trajectories of charged particles in electrostatic fields are independent of the charge to mass ratio. The technique is directly applicable to post deflection focusing tubes where the electron trajectories are not rectilinear due to the electric field between mask, screen, and the tube funnel.