Patent ID: 6680567
Filing Date: 2004-01-20
Classification: H01J

Abstract:
A glass bulb for a cathode ray tube, comprising:a panel portion having a rectangular face portion and a skirt portion, the rectangular face portion having a substantially flat outer surface and a concave inner surface, the skirt portion extending substantially vertically from a peripheral edge of the face portion; a funnel portion having one end connected to the panel portion; and a neck portion having connected to the other end of the funnel portion; wherein at least the panel portion being thermally strengthened to apply a compressive stress thereto; the panel portion satisfies the following conditions at an edge portion of a useful screen area in the face portion on a short axis or an edge portion of a useful screen area in the face portion on a long axis, whichever has a greater wall thickness: 1) 1.70&lE;TL/TC, wherein TC is a central wall thickness of the face portion, and TL is a wall thickness of the useful screen area, 2) 5 MPa&lE;|&sgr;C|&lE;14 MPa, wherein &sgr;C is the value of a strengthened compressive stress in at least an area of a side surface of the skirt portion in the vicinity of a mold match, and 3) 0.43&lE;TS/TL&lE;0.50, wherein TS is a wall thickness of a sealing end surface of the skirt portion; the funnel portion satisfies the following condition: 4) 0.37&lE;TF/TC&lE;0.49, wherein TF is a wall thickness at a portion located at B/2 when B is the length of a body portion in the funnel portion in a bulb axis direction, the body portion extending from a sealing end to a yoke portion thereof.