Hitachi, Ltd.

Hidehiro Koumura

Hisashi Nose

Takao Nakamura

Tomoki Nakamura

Noriharu Matsudate

Kentaro Oku

Atsuo Nakagawa

Kunio Ishiyama

Yasushi Sawatari

A color cathode ray tube includes a magnetic shield housed in a funnel portion thereof and a deflection device mounted in a vicinity of a transition region between a plurality of electron beams on a phosphor screen. The magnetic shield is configured so as to satisfy the inequality Dcor<Dave, where Dave&equals;(Dverm&plus;Dhorm&plus;Dcor)/3. Magnetic shield-core distances are measured in a section plane containing a longitudinal axis of the cathode ray tube and inclined at a section plane angle &thgr; with respect to a horizontal scanning direction of the plurality of electron beams. Dverm and Dhorm are magnetic shield-core distances measured at section plane angles 0&deg; and 90&deg;, respectively, and Dcor is a magnetic shield-core distance measured in a section plane intersecting a corner of a generally rectangular end of the magnetic shield facing toward an electron gun.

Color cathode ray tube having an improved internal magnetic shield

A color cathode ray tube comprises a vacuum vessel including a panel portion having a phosphor screen on its inner face, a neck portion and a funnel portion joining the neck portion and the panel portion. An inline electron gun is disposed inside of the neck portion and includes a main lens and cathode producing a center electron beam and two side electron beams. A deflection yoke for deflecting the electron beams and a pair of 2-pole ring magnets for adjusting electron beam trajectory are disposed around the neck portion. The 2-pole ring magnets have a magnetic flux density distribution at a circle which is concentric with the ring magnets, wherein the radius of the circle corresponds to the distance between adjacent electron beams at the main lens. The ratio of the amplitude of the flux density in the radial component compared to the amplitude of the flux density in the circumferential component is 0.86 to 1.38 on the circle.

Color cathode ray tube having adjustment magnet assembly at neck portion

A color cathode ray tube includes a magnetic shield of generally truncated pyramidal shape housed in its funnel portion and an electron beam deflection device. The magnetic shield is configured such that a magnetic shield-core distance between an end of a magnetic core of the deflection device facing toward the phosphor screen and an end of the magnetic shield facing toward the electron gun is approximately constant for section plane angles &thgr; in a range of 0&deg; to 360&deg;, the magnetic shield-core distance being measured in a section plane containing a longitudinal axis of the cathode ray tube and being inclined at the section plane angle &thgr; with respect to a horizontal scanning direction of the electron beams.

A cathode ray tube has a vacuum envelope including a panel portion having a phosphor screen, a neck portion having a stem fused and sealed to one end thereof, and a funnel portion for connecting the other end of the neck portion and the panel portion. The stem has stem pins annularly arrayed, sealed thereto and extending there-through for supporting an electron gun in the neck portion, and a stem mound is raised and formed integrally with the stem around a base of each of the stem pins on an electron-gun-supporting side thereof. The stem is provided with a raised outer circular edge or a flat outer circular edge. A first distance R,is defined as a distance from a center axis of the neck portion to an inner wall in a region of the neck portion facing a major portion of the electron gun, and a second distance R,is defined as a distance from the center axis to an outside edge of the stem mound as measured at half an axial height of the stem mound. The first distance R,and the second distance R,satisfy a relationship, 0<R,R,<2.1 mm.

Narrow-neck CRT having a large stem pin circle

A color cathode ray tube has a vacuum vessel including a panel portion having a phosphor screen on its inner face, a neck portion and a funnel portion jointing the neck portion and the panel portion; an electron gun assembly including an electrostatic main lens disposed in the neck portion; a deflection yoke arranged around the neck side of the funnel portion for deflecting three in-line arranged electron beams emitted from the electron gun assembly to the phosphor screen; and a 2-pole ring magnet arranged around the neck portion for adjusting the trajectories of the electron beams. The 2-pole ring magnet is arranged to have its center closer to the phosphor screen than is the center of the electrostatic main lens of the electron gun assembly. The value, as calculated by dividing the value of the radial component amplitude of the magnetic field distribution of the 2-pole ring magnet on the circumference of a circle having a radius of the s-size, by the value of the circumferential component amplitude, is 0.86 to 1.38, and preferably 0.955 to 1.275.

Color cathode ray tube having adjustment magnet assembly at the neck portion of the tube

A cathode ray tube has a vacuum envelope including a panel portion having a phosphor screen, a neck portion having a stem fused and sealed to one end thereof, and a funnel portion for connecting the other end of the neck portion and the panel portion. The stem includes plural stem pins annularly arrayed, sealed thereto and extending therethrough for supporting an electron gun in the neck portion. An outside diameter of the neck portion in a region thereof facing a major portion of the electron gun is not more than 29.1 mm. A stem mound is raised and formed integrally with the stem around a base of each of the stem pins on an electron-gun-supporting side thereof. A first distance R1 and a second distance R2 satisfy a relationship, 0&lt;R1-R2&lt;2.1 mm, where the first distance R1 is a distance from the center axis of the neck portion to an inner wall in the region of the neck portion facing the major portion of the electron gun and the second distance R2 is a distance from the center axis to an outside edge of the stem mound as measured at half an axial height of the stem mound. The number of stem pins can be ten and the plural stem pins can include two stem pins for applying focus voltages to two focus electrodes of the electron gun.

A cathode ray tube includes a panel portion having a phosphor screen, a neck portion having a stem fused and sealed to one end thereof, the stem having a plurality of stem pins annularly arrayed, sealed thereto and extending therethrough for supporting an electron gun in the neck portion and a funnel portion for connecting the other end of the neck and panel portions. A stem mound is raised and formed integrally with the stem around a base of each of the stem pins on an electron-gun-supporting side thereof. A first R1 is defined as a distance from a center axis of portion to an inner wall in a region of the neck portion facing a major portion of the electron gun, a second distance R2 is defined as a distance from the center axis tide edge of the stem mound, measured at half an axis of the stem mound, the first distance R1 and the second distance R2 satisfy a relationship, 0&lt;R1-R2&lt;2.1 mm. A wall thickness of a region of the neck portion in the vicinity of the fused and sealed regions of the neck portion and the stem is smaller than a wall thickness of a region of the neck portion facing the major portion of the electron gun.

A cathode ray tube includes a vacuum envelope formed of a panel portion having a phosphor screen on its inner surface and suspending a shadow mask therein, a neck portion having a stem sealed to one end thereof and a funnel portion for connecting the other end of the neck portion and the panel-portion. The stem has a plurality of stem pins annularly arrayed, sealed thereto and extending therethrough for supporting an electron gun in the neck portion. A stem mound is raised and formed integrally with the stem around a base of each of stem pins on a electron-gun-supporting side thereof. A first distance R1 is defined as a distance from a center axis of the neck portion to an inner wall in a region of the neck portion facing a major portion of the electron gun, a second distance R2 is defined as a distance from the center axis to an outside edge of the stem mound, measured at half an axial height of said stem mound, and a third distance is defined as a distance from an inner wall to the center axis. The third distance is not smaller than the first distance R1 at least in a region of the neck portion facing the stem mounds except in the vicinity of fused and sealed regions of the neck portion and the stem, and the first R1 distance and the second distance R2 satisfy a relationship, 0&lt;R1-R2&lt;2.1 mm.

Growing community of inventors

Goshogawara, Japan

Hidehiro Koumura