Cathode ray tube having improved curvature characteristics and method of fabrication thereof

A cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• and
• an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen, wherein the effective area of the face panel has a long axis extending in a horizontal direction and a short axis extending in a vertical direction, the effective area having a curved outer surface with a substantially infinitely large radius of curvature along the long axis and a radius of curvature along the short axis which is different between a portion on the short axis and a portion near a short side of the effective area.

A cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• and
• an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen, wherein the effective area of the face panel has a long axis extending in a horizontal direction and a short axis extending in a vertical direction, the effective area having a substantially flat outer surface and a cylindrically curved inner surface which has an infinitely large radius of curvature along the long axis and a finite radius of curvature over the whole inner surface along the short axis, said finite radius being less than said substantially infinitely large radius.

A cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• and
• an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen, wherein the effective area of the face panel has a long axis extending in a horizontal direction and a short axis extending in a vertical direction, the effective area having a curved outer surface with a substantially infinitely large radius of curvature along the long axis and an arbitrary radius of curvature along the short axis, the effective area further having a cylindrically curved inner surface with a substantially infinitely large radius of curvature along the long axis and a finite radius of curvature over the whole inner surface along the short axis, said finite radius being less than said substantially infinitely large radius.

A cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• and an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen;
• wherein the effective area of the face panel has a long axis extending in a horizontal direction and a short axis extending in a vertical direction, the effective area having a substantially flat outer surface and a curved inner surface with an arbitrary radius of curvature along the long axis and a radius of curvature alone the short axis which is different between the portion on the short axis and a portion near the short side of the effective area.

A cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• a shadow mask arranged in the vacuum envelope to oppose the phosphor screen, the shadow mask including a mask body having a substantially rectangular effective surface in opposed relation to the phosphor screen and a number of electron beam passage apertures formed in the effective surface, and a substantially rectangular frame for supporting a peripheral edge of the mask body;
• and
• an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen through the shadow mask, wherein the effective surface of the mask body has a long axis extending in a horizontal direction and a short axis extending in a vertical direction, the effective surface having substantially infinitely large radius of curvature along the long axis and a finite radius of curvature over the whole of the effective surface along a short axis, said finite radius being less than said substantially infinitely large radius.

A cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• a shadow mask arranged in the vacuum envelope to oppose the phosphor screen, the shadow mask including a
• mask body having a substantially rectangular effective surface in opposed relation to the phosphor screen and a number of electron beam passage apertures formed in the effective surface, and a substantially rectangular frame for supporting a peripheral edge of the mask body;
• and
• an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen through the shadow mask;
• wherein
• the effective surface of the mask body has a long axis extending in a horizontal direction and a short axis extending in a vertical direction, the effective surface having an infinitely large radius of curvature along the long axis and a radius of curvature along the short axis expressed by a high-order polynomial.

A method of manufacturing a cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• a shadow mask arranged in the vacuum envelope to oppose the phosphor screen, the shadow mask including a mask body having a substantially rectangular effective surface in opposed relation to the phosphor screen and a number of electron beam passage apertures formed in the effective surface, and a substantially rectangular frame for supporting a peripheral edge of the mask body;
• and
• an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen through the shadow mask;
• said method comprising:
• preparing a substantially rectangular flat mask formed with a number of electron beam passage apertures;
• subjecting the flat mask to a plastic deformation thereby to form a mask body having a cylindrically curved surface having a substantially infinitely large radius of curvature along a long axis of the mask body and having a finite curvature along a short axis of the mask body, said finite radius being less than said substantially infinitely large radius;
• and
• subjecting the mask body to an elastic deformation in such a manner that the radius of curvature along the short axis of the mask body is larger than the radius of curvature thereof at the time of the plastic deformation;
• and
• fixing a peripheral edge of the elastically deformed mask body to the frame.

A cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• and
• an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen;
• wherein,
• said effective area of the face panel has a long axis extending in horizontal direction and a short axis extending in vertical direction, the effective area having a substantially flat outer surface and a curved inner surface with an arbitrary radius of curvature along the long axis and different radius of curvature on the short axis and in the neighborhood of the vertical side of the effective area alone the short axis;
• the inner surface of the effective area of the face panel is formed to satisfy a relationship, Vp>Hp, where Hp is a fall of the inner surface at the end of the long axis relative to the center of the inner surface of the effective area, and Vp is a fall of the inner surface at the end of the short axis relative to the center of the inner surface.

A cathode ray tube comprising:

• a vacuum envelope including a face panel and a funnel, the face panel having a substantially rectangular effective area;
• a phosphor screen formed on an inner surface of the face panel;
• and
• an electron gun arranged in a neck of the funnel for emitting electron beams toward the phosphor screen, wherein
• said effective area of the face panel has a long axis extending in a horizontal direction and a short axis extending in vertical direction, the effective area having a substantially flat outer surface and a curved inner surface with an arbitrary radius of curvature;
• the inner surface of the effective area of the face panel is formed to satisfy a relationship, Vp>Hp, where Hp is the a fall of the inner surface at the end of the long axis relative to the center of the inner surface of the effective area, and Vp is a fall of the inner surface at the end of the short axis relative to the center of the inner surface.