US 6,377,003 B1Granted

Multi-beam group electron gun for beam index CRT

AssigneeChungwa Picture Tubes, Ltd.

InventorsHsing-Yao Chen, Chun-Hsien Yeh

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Abstract

For use in a beam index color cathode ray tube (CRT), a multi-beam group electron gun directs first and second groups of vertically aligned electron beams on respective parallel, horizontally aligned color phosphor stripes on the CRT's display screen. Each group of electron beams includes three beams, one for each of the three primary colors of red, green and blue. The first and second electron beam groups are horizontally offset from one another, with the upper, intermediate and lower electron beams in each group tracing the same horizontal phosphor stripe as the beams scan the display screen and with a time delay provided to synchronize the video information of both electron beam groups. A color video signal is provided either to a respective cathode or to a respective segmented conductive portion containing a beam passing aperture in the electron gun's G1 control grid for individually modulating each beam with color video image information.

Claims41

Dependent claims

An electron gun for a color index cathode ray tube (CRT) having a display screen with a plurality of horizontally aligned, vertically spaced phosphor stripes, wherein a video image is formed by sweeping a plurality of electron beams over said phosphor stripes in a raster-like manner, wherein each electron beam provides one of the three primary colors of red, green or blue of the video image, said electron gun comprising:

a cathode for providing energetic electrons;
a beam forming region (BFR) disposed adjacent to said cathode and including first and second spaced, charged grids, wherein each of said grids includes first and second vertically aligned, grouped arrays of apertures for forming said electron beams into a first leading and a second trailing group of electron beams as said electron beams are swept over the display screen, and wherein said first leading and said second trailing groups of electron beams are horizontally spaced from one another, with the electron beams in each group in vertical alignment and directed onto a respective phosphor stripe for providing one of the primary colors;
a lens disposed intermediate said BFR and the CRT's display screen for focusing the electron beams on the display screen;
and
a plurality of video signal sources coupled to either said cathode or to one of said grids in said BFR for providing color video signals thereto in modulating each of said electron beams in accordance with said color video signals;
and
a circuit for delaying the video signals displayed by said first leading group of electron beams relative to the video signals displayed by said second trailing group of electron beams in synchronizing the display of those portions of a video image formed by said first leading and second trailing groups of electron beams.

4 more elements

A color index cathode ray tube (CRT) having a glass envelope including a display screen having a plurality of horizontally aligned, vertically spaced phosphor stripes and a magnetic deflection yoke for displacing the electron beams across the display screen, wherein a video image is formed by sweeping a plurality of electron beams over said phosphor stripes in a raster-like manner, wherein each electron beam provides one of the three primary colors of red, green or blue of the video image, said index CRT comprising:

an electron gun comprising:
a cathode for providing energetic electrons;
a beam forming region (BFR) disposed adjacent to said cathode and including first and second spaced, charged grids, wherein each of said grids includes first and second vertically aligned, grouped arrays of apertures for forming said electron beams into a first leading and a second trailing group of electron beams as said electron beams are swept over the display screen, and wherein said first leading and said second trailing groups of electron beams are horizontally spaced from one another, with the electron beams in each group in vertical alignment and directed onto a respective phosphor stripe for providing one of the primary colors;
a lens disposed intermediate said BFR and the CRT's display screen for focusing the electron beams on the display screen;
and
a plurality of video signal sources coupled to either said cathode or to one of said grids in said BFR for providing color video signals thereto in modulating each of said electron beams in accordance with said color video signals;
a circuit for delaying the video signals displayed by said first leading group of electron beams relative to the video signals displayed by said second trailing group of electron beams in synchronizing the display of those portions of a video image formed by said first leading and second trailing groups of electron beams;
and
a beam index location element on the display screen responsive to an electron beam incident thereon for providing a deflection signal to the magnetic deflection yoke for maintaining the electron beams in alignment with the horizontally aligned, vertically spaced phosphor stripes.

6 more elements

Dependencies are inferred from the claim text.