BEAM INDEX TYPE CATHODE RAY TUBE

摘要

PURPOSE: A beam index type cathode ray tube is provided to correct efficiently an electron beam by using an auxiliary deflection device for obtaining a big rotary angle. CONSTITUTION: A fluorescent layer screen(2) having an index stripe is formed on an inner face of a panel(4). An electron gun(12) is formed on an inner circumference of a neck portion(8) in order to emit an electron beam to the fluorescent layer screen(2). The electron gun(12) is formed with a cathode and a multitude of grid electrodes. An optical detector(18) is formed on an outer face of a funnel(6) for connecting the panel(4) with the neck portion(8) in order to detect an index beam from the index stripe. An index circuit portion(20) applies correctly a color signal to the electron gun(12) by synchronizing an index signal of the optical detector(18) with the color signal. A deflection yoke(14) deflects the electron beam by generating a deflective magnetic field. An auxiliary deflection portion(22) is installed on an outer circumference of the neck portion(8) in order to correct a trigger slope of the electron beam.