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US 4,777,401 AGranted
Color picture tube having a face panel with an outer face having a hyperbolic curvature
AssigneeMatsushita Electronics Corporation
InventorsKakuichiro Hosokoshi, Shigeya Ashizaki, Osamu Konosu, Osamu Adachi
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Abstract
In a color picture tube, curvature of outside face of said face panel is defined by ##EQU1## wherein Z is a distance in a direction of tube axis from an X-Y plane tangential at the center of the face, r is a distance from the center of the face panel to said point therealong, and A and B are constants of positive integers, respectively; thus the face panel excludes point of inflection and the reproduced picture thereon has a flat appearance, without trouble of undesirable doming of shadow mask.
Claims5
A color picture tube comprising:
- a vacuum enclosure having a face panel of a substantially rectangular shape having color phosphor dots or stripes on an inside face thereof,
- a shadow mask disposed in the enclosure with a predetermined gap to said inside face of the face panel, and
- means for emitting electrons including control means for controlling electron beam density,
- an outside face of said face panel having a hyperbolic curvature without a point of inflection and defined by the equation ##EQU7## wherein Z is a distance in a direction of tube axis from a plane tangential at the center of the outside face to a point on the outside face,
- r is a distance of the tube axis to said point therealong, and
- A and B are values independent of r, respectively.
3 more elements
Dependencies are inferred from the claim text.