Cathode ray tube with improved mask assembly

A cathode ray tube comprising:

• a vacuum tube comprising a panel in which a fluorescence screen is formed, a funnel that is provided to a rear part of the panel, and a neck;
• an electron gun positioned inside the neck;
• a deflection yoke positioned outside the funnel;
• and
• a shadow mask positioned inside the panel with a predetermined distance to the fluorescence screen and having an aperture portion including a plurality of beam guide holes, a non-aperture portion surrounding the aperture portion, and a skirt portion bent from an edge of the non-aperture portion toward the electron gun,
• wherein the non-aperture portion includes a pair of longer sides, a pair of shorter sides, and four corner portions, and a first width of the non-aperture portion measured at the longer side and a second width of the non-aperture portion measured at the shorter side are formed to be less than a third width of the non-aperture portion measured at one of the corner portions,
• wherein the shadow mask satisfies the following conditions:
• 2 mm≦w1<w3, and 2 mm≦w2<w3, where w1 denotes the first width of the non-aperture portion, w2 denotes the second width of the non-aperture portion, and w3 denotes the third width of the non-aperture portion.