Color cathode ray tube having a shadow mask with a plurality of strip shaped reinforcing beads

A color cathode ray tube comprising:

• an envelope including a panel and a funnel joined to the panel, the panel having a substantially rectangular effective portion and a phosphor screen formed on an inner surface of the effective portion;
• a shadow mask arranged to oppose the phosphor screen;
• and
• an electron gun provided within a neck of the funnel, for emitting electron beams onto the phosphor screen through the shadow mask;
• the shadow mask comprises:
• a substantially rectangular effective surface having a large number of electron beam passage apertures formed therein, for allowing the electron beams to pass therethrough, the effective surface having a center located on a tube axis, and a longer axis and a shorter axis extending perpendicular to each other through the center;
• and
• a plurality of reinforcing beads formed on the effective surface to reinforce the effective surface, the reinforcing beads projecting from the effective surface and having heights which vary in accordance with positions such that in at least a part of that area of the effective surface on which the reinforcing beads are provided, the heights of the reinforcing beads satisfy the following relationship:
• dx1>dx2, dy1>dy2
• where dx1 denotes the height measured at a first position which is apart from the longer axis, and which is a distance x1 apart from the shorter axis,
• dx2 denotes the height measured at a second position which is further apart from the longer axis than the first position, and which is a distance x2 apart from the shorter axis,
• dy1 denotes the height measured at a third position which is located on the shorter axis, and which is a distance y1 apart from the longer axis, and
• dy2 denotes the height measured at a fourth position which is apart from the shorter axis, and which is a distance y2 apart from the longer axis, and
• the distances x1, x2, y1 and y2 satisfy the following relationship:
• x1=x2=y1=y2.

A color cathode ray tube comprising:

• an envelope including a panel and a funnel joined to the panel, the panel having a substantially rectangular effective portion and a phosphor screen formed on an inner surface of the effective surface;
• a shadow mask arranged to oppose the phosphor screen;
• and
• an electron gun provided within a neck of the funnel, for emitting electron beams onto the phosphor screen through the shadow mask;
• the shadow mask including:
• a substantially rectangular effective surface having a large number of electron beam passage apertures formed therein, for allowing the electron beams to pass there through, the effective surface having a center located on a tube axis, and a longer axis and a shorter axis extending perpendicular to each other through the center;
• and
• a plurality of reinforcing beads formed on the effective surface to project therefrom and reinforcing the effective surface, the reinforcing beads extending in parallel with the longer axis, and being provided in a region having a width of dL/3, where dL is a distance between long sides of the effective surface.

A color cathode ray tube comprising:

• an envelope comprising a panel and a funnel joined to the panel, the panel having a substantially rectangular effective portion and a phosphor screen formed on an inner surface of the effective portion;
• a shadow mask arranged to oppose the phosphor screen;
• and
• an electron gun provided within a neck of the funnel, for emitting electron beams onto the phosphor screen through the shadow mask;
• the shadow mask including:
• a substantially rectangular effective surface having a large number of electron beam passage apertures formed therein, for allowing the electron beams to pass therethrough, the effective surface having a center located on a tube axis, and a longer axis and a shorter axis extending perpendicular to each other through the center;
• and
• a plurality of reinforcing beads formed on the effective surface to project therefrom and reinforcing the effective surface, the reinforcing beads extending in parallel with the short axis, and being provided in a region having a width of dS/3, where dS is a distance between short sides of the effective surface.