Hitachi, Ltd.

Haruhiko Yoshida

Mitsuru Watanabe

Nobuhiko Hosotani

Hiroshi Ito

Hiroshi Yoshioka

Hiroshi Itou

A color cathode ray tube having a panel portion includes a faceplate portion, a skirt portion, a neck portion and funnel portion. The faceplate portion has a screen to display an image, and the panel portion has a shadow mask installed therein. The neck portion accommodates an electron gun therein and the funnel portion connects the panel portion and the neck portion. A relation RDO&minus;tc<RDI holds, wherein, RDO is a radius of curvature connecting the center of the screen and the diagonal edge of the screen of the outer surface of the faceplate, RDI is a radius of curvature connecting the center of the screen and the diagonal edge of the screen of the inner surface of the faceplate, and tc is a thickness of the faceplate at the screen center. A black matrix hole transmittivity in the diagonal direction peripheral areas is not greater than 110% of that of the central area.

Cathode ray tube having specific radius of curvatures for inner and outer surface of the panel

A color cathode ray tube is constituted of a glass bulb which includes a panel portion having a faceplate portion with a phosphor screen on an inner surface thereof, a neck portion in which an electron gun is mounted, and a funnel portion which connects the panel portion and the neck portion. Assuming a thickness of a screen effective area of the faceplate portion along the tube axis direction as tc at a central section thereof, as tx at a peripheral section thereof along the major axis direction, and as td at a peripheral section thereof along the diagonal direction, the cathode ray tube has the relationship tc>td>tx.

Color cathode ray tube

A color cathode ray tube includes a generally rectangular shadow mask structure in which a skirt portion of a shadow mask is secured to a support frame. The shadow mask is formed by an apertured portion having a large number of electron beam transmission apertures, an imperforate portion disposed around the entire periphery of the apertured portion, a skirt portion being bent back and drooping from the entire periphery of the imperforate portion, and a support frame including a rectangular frame portion. The skirt portion of the shadow mask is secured to the inside of the rectangular frame portion, and a bent portion of the shadow mask, which defines a transitional region between the imperforate portion, and the skirt portion is formed in a shape where long sides are recessed inwardly and ends of the long sides of the skirt portion come into contact with the frame portion.

Color cathode ray tube having a shadow mask structure

A color cathode ray tube includes a shadow mask having an apertured portion, an imperforate portion and a skirt portion. The shadow mask of an iron-nickel alloy is suspended within a support frame, has a descending step portion around the imperforate portion, the skirt portion which is fitted in the support frame is integral with the descending step portion, is provided with plural beads parallel with a height of the skirt portion and protruding inward. The descending step portion satisfies one of conditions (a)-(c) of (a) its height is from 30% to of H , (b) its width is from 65% to 80% of W , or (c) its height H and width W are from 30% to 50% of H and from 65% to 80% of W , respectively, where H and W are its height and width at centerlines of long and short sides of the skirt portion, respectively.

Shadow mask type color cathode ray tube having a shadow mask with curls thereof reduced

A cathode ray tube comprising a panel portion that has a phosphor screen formed over the inner surface of the faceplate A. The faceplate A is formed such that the radius of curvature Ri of its inner surface A is almost equal to or larger than the radius of curvature Ro of its outer surface A and that the black matrix hole transmittivity is defined at a specified level. The cathode ray tube is provided with a simple means which allows the brightness in the peripheral area of the faceplate A to match the brightness in the central area and which, even when the deflection angle is large, can reduce the deflection voltage supplied to the deflection yoke and thereby reduce the leakage magnetic field from the deflection yoke.

Cathode ray tube faceplate having particular black matrix hole transmittivity in the peripheral areas

A color cathode ray tube is provided with a shadow mask structure which includes a shadow mask formed by integrally forming an apertured portion, an imperforate portion and a skirt portion, and a support frame having a frame portion into which the skirt portion is fitted. The skirt portion of the shadow mask has respective long sides and respective short sides thereof recessed inwardly, and the frame portion has respective long sides and respective short sides formed in planes having no welding bosses, and the skirt portion is fitted into and welded to the frame portion. Furthermore, an end of the outside of the skirt portion and the inner wall of the frame portion have respective entire peripheries thereof come into contact with each other. With such a construction, the shadow mask structure has a small magnetic resistance and the shadow mask is prevented from being vibrated at the time an external vibration is applied to the cathode ray tube. Furthermore, the shadow mask can be easily assembled and can provide an apertured portion which is free from deformation.

A color cathode ray tube includes an evacuated envelope having a panel portion, a neck portion, and a funnel portion for connecting the panel portion and the neck portion, a generally rectangular shadow mask having a curved apertured portion having a multiplicity of electron-transmissive apertures, a curved imperforate portion surrounding and integral with the apertured portion and a peripheral skirt portion, a generally rectangular support frame for suspending the shadow mask by spot welding the peripheral skirt portion thereto, within said panel portion, a phosphor screen formed on an inner surface of the panel portion, an electron gun housed in the neck portion, and a deflection yoke. The shadow mask is provided with a descending step portion extending along an outer edge of the imperforate portion, the peripheral skirt portion is formed by being bent back from an outer edge of the descending step portion, and the peripheral skirt portion is provided with a plurality of beads extending in a direction of a height of the peripheral skirt portion and protruding inward in each side of the peripheral skirt portion.

Growing community of inventors

Sakura, Japan

Haruhiko Yoshida