Projection tube having different neck diameters

摘要

A projection tube having a high focusing performance at a low deflection power includes a funnel, a neck portion and a stem portion which seals the neck portion. The neck portion of the projection tube includes a first neck portion which is connected to the funnel and has a first neck outer diameter, and also includes a second neck portion which accommodates an electron gun and has a second neck outer diameter which is larger than the first neck outer diameter.