In=line electron gun for colour CRT - produces horizontal object point further from main lens than vertical point and shorter vertical focal length than horizontal

摘要

A triode section (1) produces three electron beams. These are focussed by a main lens (2) to produce dots on a screen. As seen from the main lens (2), each electron beam has a vertical object point, a horizontal object point, a vertical emission capacity and a horizontal emission capacity. The triode section (1) is formed such that the horizontal object point is further from the main lens (2) than the vertical object point, and the vertical emission capacity is smaller than the horizontal. The vertical focal length of the main lens (2) is shorter than the horizontal focal length. USE/ADVANTAGE - Provides high resolution over whole screen. Provides sharply focussed dots both in middle and at edges of screen and maintains circular dot of reduced dia.