Projection tube apparatus

摘要

A projection tube apparatus includes: a valve made up of a face panel having a screen face on its external face, a funnel connected to a rear portion of the face panel, and a neck portion; an electron gun that emits an electron beam and is housed in the neck portion; and a deflection device mounted at an outer circumference of the funnel on the neck portion side. The deflection device at least includes: horizontal deflection coils that generate a horizontal deflection field for deflecting the electron beam in the horizontal direction; vertical deflection coils that generate a vertical deflection field for deflecting the electron beam in the vertical direction and is disposed outside the horizontal deflection coils; and a ferrite core disposed outside the vertical deflection coils. A distance Ls between an end portion of the horizontal deflection coils on the screen face side and the screen face is set to 55 mm<=Ls<=80 mm.