An electron beam current modulator is provided between a cathode and a laser screen of a cathode-ray tube and has at least three deflecting plates positioned around, and symmetrically with respect to an optical axis of the cathode-ray tube and a diaphragm having an aperture of a regular shape. An electromagnetic...http://www.google.de/patents/US5280360?utm_source=gb-gplus-sharePatent US5280360 - Laser screen cathode ray tube with beam axis correction
