PICK-UP TUBE

• Main Authors: FUNAKI TOSHIHARU, TAKAYAMA SHIGEHIKO, TAKANO KOU, MARUYAMA MASANORI
• Format: Patent
• Language: English
• Published: 07.10.1985
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

PURPOSE:To make a return beam to reflect for preventing it from reaching outside the scanning range by providing a disk-shaped electrode on the third electrode forming the main lens part in a pick-up tube of a static current forcusing type while providing the fourth electrode with a cylindrical electrode. CONSTITUTION:A pick-up tube is formed of the electron beam generation part consisting of the cathode K, the first and second electrodes G1, G2 and the main lens part consisting of the third and fourth electrodes G3, G4 and a mesh electrode G5 in order to make the electron beam to scan on a photoconductive film target 4. Thereby, the third electrode G3 is provided with a disk-shaped electrode 11 while providing the fourth electrode G4 with a cylindrical electrode 12 for making a return beam 8 pushed back by the mesh electrode G5 and the photoconductive film target 4 to be reflected by the electrode 11 followed by being reflected on the inside of the electrode 12 for going inside the scanning range A of the target 4. Accordingly, the reflection beam reaching the outside B of the scanning range can be removed thus preventing the generation of a false signal.