Color cathode ray tube having an improved electron gun
First Claim
1. A color cathode ray tube comprising:
- an evacuated envelope comprising a panel portion, a neck portion and a funnel portion for connecting said panel portion and said neck portion;
a three-color phosphor screen formed on an inner surface of said panel portion;
a shadow mask having a multiplicity of apertures therein and spaced from said phosphor screen;
a three-beam in-line type electron gun housed in said neck portion;
said three-beam in-line type electron gun including an electron beam generating section for generating three electron beams and a main lens section for focusing said three electron beams on said three-color phosphor screen; and
a deflecting device mounted in a vicinity of a transition region between said funnel portion and said neck portion for scanning said three electron beams on said three-color phosphor screen;
said main lens section comprising a focus electrode and an anode facing said focus electrode;
wherein said main lens section comprises a focus electrode and an anode facing said focus electrode, said focus electrode being composed of plural focus electrodes;
each of said anode and a first one of said focus sub-electrodes facing said anode comprises a first electrode member having a single opening common for said three electron beams in an end thereof facing another of said anode and said first one of said focus sub-electrodes, and a second electrode member set back from said end of said first electrode member for forming three beam apertures for passing said three electron beams, respectively; and
a following inequality being satisfied;
(A+566)/106>
H−
2×
S;
where A is V1×
V2×
t, V1 is a vertical diameter of said single opening, V2 is a vertical diameter of a center one of said three beam apertures, T is an axial distance between said single opening and said second electrode member, H is a horizontal diameter of said single opening, and S is P×
L/Q, where P is a horizontal center-to-center spacing between adjacent phosphor elements at a center of said three-color phosphor screen, Q is an axial spacing between said three-color phosphor screen and said shadow mask at the center of said three-color phosphor screen, and L is an axial distance between said shadow mask and said single opening in said focus electrode member of said first one of said focus sub-electrodes.
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Abstract
Each of an anode and one of the sub-electrodes of a main lens of a shadow mask color cathode ray tube includes a first member having a single opening in their facing ends, and a second member having three beam apertures, wherein (A+566)/106>H−2×S is satisfied, where A is V1×V2×T, V1 is a vertical diameter of the opening, V2 is a vertical diameter of the center beam aperture, T is a distance between the opening and the second electrode member, H is a horizontal diameter of the opening, S is P×L/Q, where P is a horizontal center-to-center spacing between adjacent phosphor elements, Q is a spacing between the phosphor screen and the shadow mask, and L is a distance between the shadow mask and the opening in the first member.
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Citations
7 Claims
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1. A color cathode ray tube comprising:
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an evacuated envelope comprising a panel portion, a neck portion and a funnel portion for connecting said panel portion and said neck portion;
a three-color phosphor screen formed on an inner surface of said panel portion;
a shadow mask having a multiplicity of apertures therein and spaced from said phosphor screen;
a three-beam in-line type electron gun housed in said neck portion;
said three-beam in-line type electron gun including an electron beam generating section for generating three electron beams and a main lens section for focusing said three electron beams on said three-color phosphor screen; and
a deflecting device mounted in a vicinity of a transition region between said funnel portion and said neck portion for scanning said three electron beams on said three-color phosphor screen;
said main lens section comprising a focus electrode and an anode facing said focus electrode;
wherein said main lens section comprises a focus electrode and an anode facing said focus electrode, said focus electrode being composed of plural focus electrodes;
each of said anode and a first one of said focus sub-electrodes facing said anode comprises a first electrode member having a single opening common for said three electron beams in an end thereof facing another of said anode and said first one of said focus sub-electrodes, and a second electrode member set back from said end of said first electrode member for forming three beam apertures for passing said three electron beams, respectively; and
a following inequality being satisfied;
(A+566)/106>
H−
2×
S;
where A is V1×
V2×
t,V1 is a vertical diameter of said single opening, V2 is a vertical diameter of a center one of said three beam apertures, T is an axial distance between said single opening and said second electrode member, H is a horizontal diameter of said single opening, and S is P×
L/Q,where P is a horizontal center-to-center spacing between adjacent phosphor elements at a center of said three-color phosphor screen, Q is an axial spacing between said three-color phosphor screen and said shadow mask at the center of said three-color phosphor screen, and L is an axial distance between said shadow mask and said single opening in said focus electrode member of said first one of said focus sub-electrodes. - View Dependent Claims (2, 3)
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4. A color cathode ray tube comprising:
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an evacuated envelope comprising a panel portion, a neck portion and a funnel portion for connecting said panel portion and said neck portion;
a three-color phosphor screen formed on an inner surface of said panel portion;
a shadow mask having a multiplicity of apertures therein and spaced from said phosphor screen;
a three-beam in-line type electron gun housed in said neck portion;
said three-beam in-line type electron gun including an electron beam generating section for generating three electron beams and a main lens section for focusing said three electron beams on said three-color phosphor screen; and
a deflecting device mounted in a vicinity of a transition region between said funnel portion and said neck portion for scanning said three electron beams on said three-color phosphor screen;
wherein said main lens section comprises a focus electrode and an anode facing said focus electrode, said focus electrode being composed of plural focus sub-electrodes each of said anode and a first one of said focus sub-electrodes facing said anode comprises a first electrode member having a single opening common for said three electron beams in an end thereof facing another of said anode and said first one of said focus sub-electrodes, and a second electrode member set back from said end of said first electrode member for forming three beam apertures for passing said three electron beams, respectively;
said focus sub-electrodes include at least one sub-electrode of a first group adapted to be supplied with a first focus voltage and at least one sub-electrode of a second group adapted to be supplied with a second focus voltage;
said second focus voltage being a fixed voltage superposed with a dynamic voltage varying with deflection of said three electron beams;
an electrostatic quadrupole lens is formed between facing ends of one of said at least one sub-electrode of said first group and one of said at least one sub-electrode of said second group facing said one of said at least one sub-electrode of said first group; and
a following inequality is satisfied;
V1>
H−
2×
S;
where V1 is a vertical diameter of said single opening, H is a horizontal diameter of said single opening, and S is P×
L/Q,where P is a horizontal center-to-center spacing between adjacent phosphor elements at a center of said three-color phosphor screen, Q is an axial spacing between said three-color phosphor screen and said shadow mask at the center of said three-color phosphor screen, and L is an axial distance between said shadow mask and said single opening in said first electrode member of said first one of said focus sub-electrodes. - View Dependent Claims (5, 6, 7)
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Specification