Color picture tube
AssigneeMatsushita Toshiba Picture Display Co., Ld.
InventorShuji Makimoto
Life of this patent
Estimating the term…
Abstract
A perforated curved-surface portion of a shadow mask in a color picture tube satisfies the following conditions. At an arbitrary point on an X-axis and a Y-axis, Rr is one radius of curvature of a main radius of curvature group, and R1 is the other radius of curvature of the main radius of curvature group. On the Y-axis, |Rr|<|R1| is satisfied at an arbitrary point in a range where the distance from a center is LY or less. On the X-axis, |Rr|>|R1| is satisfied at an arbitrary point in a range where the distance from the center is Lx/3 or less, and |Rr|<|R1| is satisfied at an arbitrary point in a range where the distance from the center is 3 Lx/4 to LX. This can enhance mask curved-surface strength without degrading resolution and color purity.
Claims6
A color picture tube, comprising:
- a panel having an outer surface with a radius of curvature of 10,000 mm or more;
- a funnel connected to the panel;
- a phosphor screen provided on an inner surface of the panel;
- an electron gun provided in the funnel;
- and
- a shadow mask provided in the panel so as to be opposed to the phosphor screen and having a substantially rectangular perforated curved-surface portion with a plurality of apertures,
- wherein assuming that an axis in a long side direction of the perforated curved-surface portion, which passes through a center of the perforated curved-surface portion, is an X-axis, an axis in a short side direction of the perforated curved-surface portion, which passes through the center, is a Y-axis, a length from the center to an end portion on the X-axis of the perforated curved-surface portion is Lx, a length from the center to an end portion on the Y-axis of the perforated curved-surface portion is LY, a radius of curvature in a radial direction of the perforated curved-surface portion at an arbitrary point (X, Y) of the perforated curved-surface portion is Rr(X, Y) and a radius of curvature in a direction vertical to the radial direction of the perforated curved-surface portion is R1(X, Y), and a main radius of curvature group consists of a maximum radius of curvature and a minimum radius of curvature at the arbitrary point (X, Y) of the perforated curved-surface portion,
- at an arbitrary point on the X-axis and the Y-axis, Rr(X, Y) is one radius of curvature of the main radius of curvature group, and R1(X, Y) is the other radius of curvature of the main radius of curvature group,
- on the Y-axis, |Rr(0, Y)|<|R1(0, Y)| is satisfied at an arbitrary point in a range where the distance from the center is LY or less, and
- on the X-axis, |R,(X, 0)|>|R1(X, 0)| is satisfied at an arbitrary point in a range where the distance from the center is Lx/3 or less, and |Rr(X, 0)|<|R1(X, 0)| is satisfied at an arbitrary point in a range where the distance from the center is 3 Lx/4 to Lx.
Dependencies are inferred from the claim text.