US 2006/0170326 A1Published application

Glass bulb for cathode ray tube

AssigneeAsahi Glass Company, Limited

InventorToshihide Murakami

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Abstract

A flat glass bulb for a cathode ray tube, which is light weight and provides good productivity, is realized. The external shape of a cross section of a body portion 3 near the yoke portion, perpendicular to the bulb axis, is made to be a substantially rhombic shape or a substantially bobbin shape, the maximum diameter direction of the substantially rhombic cross section is made to be the same as the long axis direction of a funnel, maximum-diameter portions are provided between the long axis and diagonal axes when the cross sectional shape is the substantially bobbin shape, and the body portion is made to be constituted by a smooth continuous surface without having a step, a protrusion or recess, in which the minimum value of the differential value h=f(s) is made to be at least 0 provided that the distance from the yoke end in the direction perpendicular to the bulb axis is s, whereby the stress formed in the yoke portion is reduced to realize a flat cathode ray tube having high reliability.

Claims6

Dependent claims

A glass bulb for a cathode ray tube, comprising a glass panel and a glass funnel, the glass panel having an inner face forming a substantially rectangular phosphor screen, the glass funnel comprising a neck portion accommodating an electron gun, a yoke portion from a neck seal position to a yoke end, and a body portion from the yoke end to the seal edge portion;

characterized in that D and H satisfy a relation 3.2≦D/H≦4.8 provided that the length of a diagonal line of the phosphor screen is D and the distance from the end of the diagonal line to the reference line of the glass funnel in the direction in parallel with bulb axis is H;
the external shape of the yoke portion in cross section perpendicular to the bulb axis, at the portion of the reference line, is in a substantially rectangular shape;
in a region where a height h of the body portion from the yoke end in the direction of bulb axis, satisfies 0.1Hb<h<0.3Hb provided that the height of the body portion in the direction of bulb axis is Hb, the external shape of the body portion in cross section perpendicular to the bulb axis is in a substantially rhombic shape and the direction of maximum diameter in the substantially rhombic shape is the same as the long axis direction of the funnel;
and the minimum value of the differential value of h=f(s) is at least 0 provided that the distance from the yoke end in the direction perpendicular to the bulb axis is s.

1 more element

characterized in that D and H satisfy a relation 3.2≦D/H≦4.8 provided that the length of a diagonal line of the phosphor screen is D and the distance from the end of diagonal line to the reference line of the glass funnel in the direction in parallel with the bulb axis is H;
the external shape of the yoke portion in cross section perpendicular to the bulb axis, is in a substantially rectangular shape, and in the external shape of the body portion in cross section perpendicular to the bulb axis in the region where a height h from the yoke end of the body portion in the direction of bulb axis satisfies 0.1Hb<h<0.3Hb provided that the height of the body portion in the direction of bulb axis is Hb, the maximum diameter portions of the external shape are present between the long axis and the respective diagonal axes, and an inwardly recessed intermediate portion between two maximum diameter portions in each short side is inwardly recessed;
and the minimum value of the differential value of h=f(s) is at least 0 provided that the distance from the yoke end in the direction perpendicular to the bulb axis in the external shape is s.

Dependencies are inferred from the claim text.