CRT's have a plates to accelerate towards screen then a focus zone to tightly focus the beam to a pixel size then high voltage deflection beam from the flyback sawtooth generator to sweep both horizontally fast up to 250 Mpix/s in high res CRT's then slow sweep for vertical or using XY vector text writing with some old scopes between raster scans. Then blanked on Z axis during retrace.

The negative plate polarity repels the fast moving electrons on the focus ring towards a laser like dot so that almost 4k resolutions could be seen on Ilya and Hitachi CRT's with 4:3 aspect ratio. My old PC did 2k horizontal pixels by 2680 vert or more than >5 Megpixels. At 50 Hz NI that was a 250 MHz pixel clock.

anode leakage is low by design.

CRT's have a plates to accelerate towards screen then a focus zone to tightly focus the beam to a pixel size then high voltage deflection beam from the flyback sawtooth generator to sweep both horizontally fast up to 250 Mpix/s in high res CRT's then slow sweep for vertical or using XY vector text writing with some old scopes between raster scans. Then blanked on Z axis during retrace.

The negative plate polarity repels the fast moving electrons on the focus ring towards a laser like dot so that almost 4k resolutions could be seen on Ilya and Hitachi CRT's with 4:3 aspect ratio. My old PC did 2k horizontal pixels by 2680 vert or more than >5 Megpixels. At 50 Hz NI that was a 250 MHz pixel clock.