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US 2007/0126332 A1Published application
Color picture tube
AssigneeMatsushita Toshiba Picture Display Co., Ltd.
InventorsTakashi Murai, Tadahiro Kojima, Takeshi Nakayama, Nobuyuki Seto
Life of this patent
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Abstract
The radii of curvature RD, RS and RL along a diagonal axis, a short side and a long side of an outer surface of a useful portion of a panel whose inner surface is provided with a phosphor screen satisfy RD≧10 m, RS>RD, and RL>RD. This makes it possible to provide a color picture tube that has an excellent visibility and is not susceptible to the deterioration in color purity due to doming, while including a shadow mask with excellent formability and strength.
Claims10
A color picture tube comprising:
- a panel having a substantially rectangular useful portion whose inner surface is provided with a phosphor screen;
- and
- a shadow mask having a perforated region as a curved surface provided with a large number of apertures for passing electron beams;
- wherein, assuming that an axis that is perpendicular to a tangent plane to an outer surface of the useful portion at a center of the useful portion and passes through the center is a tube axis and a point of intersection of a short side and a long side of the useful portion is a diagonal axis end,
- the color picture tube satisfies
- RD≧10 m,
- RS>RD, and
- RL>RD,
- where RD, defined by
- RD=[(SD/2)2+ZD2]/(2×ZD) (1)
- using a dimension SD of the useful portion in a direction of the diagonal axis and a sagging amount ZD along a direction of the tube axis at the diagonal axis end with respect to the center on the outer surface of the useful portion, indicates a radius of curvature along the diagonal axis of the outer surface of the useful portion, RS indicates a radius of curvature along the short side of the outer surface of the useful portion, and RL indicates a radius of curvature along the long side of the outer surface of the useful portion.
8 more elements
Dependencies are inferred from the claim text.