Color cathode ray tube
View Patent ↗A color cathode ray tube capable of improving the luminance attenuation characteristic and the explosion-proof characteristic through an improved shape of a panel is disclosed. In an equation F=Rdo/(Sd H 1.767), F>21, Tc/CFT≦1.35, and Rdi>(Ryi or Rxi) are satisfied, wherein Sd is a length of a diagonal effective picture of the panel, Rdo is a curvature radius of a diagonal outer surface, Ryo is a curvature radius of a vertical outer surface, Rxi, Ryi and Rdi are a horizontal, vertically and diagonal curvature radius, respectively, CFT is a thickness of a center portion, Tc is a thickness of a diagonal end of the effective surface, F is a planarizing rate of the outer curvature.
1. A flat color cathode ray tube including a vacuum envelope composed of a panel, a funnel, and a neck, the panel having a generally flat outer surface and a convex inner surface having a curvature with respect to an axis of the cathode ray tube, the inner surface having an effective surface on which a phosphor screen is formed, a grill or stripe-type mask being opposed to the inner surface of the panel and extended in a vertical direction,
wherein in an equation F=Rdo/(Sd×1.767), conditions of F>21, Tc/CFT≦1.35, and Rdi>(Ryi or Rxi) are satisfied,
where Sd is a length of a diagonal effective picture of the panel, Rdo is a curvature radius of a diagonal outer surface, Ryo is a curvature radius of a vertical outer surface, Rxi, Ryi and Rdi are a horizontal, vertical and diagonal curvature radius, respectively, CFT is a thickness of a center portion, Tc is a thickness of a diagonal end of the effective surface, F is a planarizing rate of the outer curvature.
2. The cathode ray tube as claimed in claim 1 , wherein a relationship of 0.81≦Ryi/Rdi≦0.99 is satisfied between the inner curvature radius of the respective axis.
3. The cathode ray tube as claimed in claim 1 , wherein a relationship of 0.99≦Ryi/Rxi≦1.359 is satisfied between the inner curvature radius of the respective axis.
4. The cathode ray tube as claimed in claim 1 , wherein structure of the inner curvature radius of the panel is satisfied with Rdi>Ryi>Rxi.
5. The cathode ray tube as claimed in claim 1 , wherein a relationship of 0.81≦Ryi/Rdi≦0.99 and 0.99≦Ryi/Rxi≦1.35 is satisfied between the inner curvature radius of the respective axis.
6. The cathode ray tube as claimed in any one of claims 1 to 5 , wherein a relationship of 0.08≦Ryi/Ryo≦0.11 is satisfied between the vertical outer curvature radius and the vertical inner curvature radius.
7. The cathode ray tube as claimed in claim 2 or claim 3 , wherein a relationship of 0.82≦Ryi/Rdi≦0.95 is satisfied between the vertical inner curvature radius Ryi and the diagonal inner curvature radius Rdi, or a relationship of 1.00≦Ryi/Rxi≦1.30 is satisfied between the vertical inner curvature radius Ryi and the horizontal inner curvature radius Rxi.