http://vimeo.com/28588617 I stumbled across this old video of a Charactron tube by General Dynamics. (It was in my collection so I converted it to a web-friendly formate and hosted it on Vimeo.) I have a similar tube by Raytheon that acts as a monoscope that works on the same principle. Hopefully someone else enjoys this video!
The Charactron CRT used an electron beam to flood a specially patterned perforated anode that contained the stencil patterns for each of the characters that it could form. The first deflection positioning of the electron beam steered the beam to pass through one of the (typically 64 or 116) characters and symbols that could be formed. The beam, which then had the cross-section of the desired character, was re-centered along the axis of the tube and deflected to the desired position of the screen for display. Alternately, as in the accompanying image, the entire matrix was filled with the electron beam then deflected through a selection aperture to isolate one character.