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US 4,626,738 AGranted
Color display tube with electrostatic focusing lens
AssigneeU.S. Philips Corporation
InventorHans G. Gerlach
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AssigneeU.S. Philips Corporation
InventorHans G. Gerlach
Estimating the term…
A color display tube comprising an evacuated envelope (1) composed of a neck (4), a cone (3) and a display window (2), contains in the neck a system of electron guns (5) with which three electron beams are generated. The beams are situated with their axes in one plane and are focused by means of a focusing lens field on a display screen (10) provided on the inside of the display window. The focusing lens field is formed between two electrodes (25, 26) of the electron gun system which are situated behind each other along the axes. The electrodes comprise facing outermost rims (32, 33) and includes respective apertures (38, 39, 40), (42, 43, 44) which are symmetrical with respect to the plane and through which the electron beams pass within the rims. The apertures are formed in recessed parts (34, 41) extending substantially at right angles to the axes. By making the shape of at least one of the central apertures (39, 43) so that, in addition to providing a quadrupole component, it substantially compensates an eight-pole component in the focusing lens field at the area of the central electron beam, and by making the shape of the outermost apertures in at least one of the electrodes so that, in addition to providing a quadrupole component, they substantially compensate a six-pole component in the focusing lens field at the area of the outermost electron beams, a better spot on the display screen is obtained.
A color display tube comprising an evacuated envelope containing a luminescent screen and an electron gun system for producing a central electron beam and first and second outer electron beams along respective axes lying in a single plane, said electron gun system including first and second spaced-apart electrodes for producing therebetween a focusing lens field to focus the electron beams at the luminescent screen, said electrodes having facing rims extending from respective first and second recessed parts, each of said recessed parts extending transversely with respect to the axes and having central and first and second outer apertures for passing the respective electron beams;
A color display tube comprising an evacuated envelope containing a luminescent screen and an electron gun system for producing a central electron beam and first and second outer electron beams along respective axes lying in a single plane, said electron gun system including first and second spaced-apart electrodes for producing therebetween a focusing lens field to focus the electron beams at the luminescent screen, said electrodes having facing rims extending from respective first and second recessed parts, each of said recessed parts extending transversely with respect to the axes and having central and first and second outer apertures for passing the respective electron beams;
A color display tube comprising an evacuated envelope containing a luminescent screen and an electron gun system for producing a central electron beam and first and second outer electron beams along respective axes lying in a single plane, said electron gun system including first and second spaced-apart electrodes for producing therebetween a focusing lens field to focus the electron beams at the luminescent screen, said electrodes having facing rims extending from respective first and second recessed parts, each of said recessed parts extending transversely with respect to the axes and having central and first and second outer apertures for passing the respective electron beams;
Dependencies are inferred from the claim text.