Patent ID: 6157120
Filing Date: 2000-12-05
Classification: H01J

Abstract:
A color cathode ray tube (CRT) for displaying a color video image, said CRT comprising:an electron gun for providing a plurality of electron beams, wherein said electron beams are arranged in an inline array;a generally rectangular display screen having a generally spherical curvature and a plurality of discrete phosphor deposits on an inner surface thereof, wherein each phosphor deposit emits red, green or blue light when an associated electron beam is incident thereon, said display screen having a first inner area defined by a first radius of curvature R.sub.1 from a center of the display screen to a distance D from said center and a second outer area defined by a second radius of curvature R.sub.2 from D to a peripheral edge of said display screen, where R.sub.1 >>R.sub.2 ; anda generally rectangular shadow mask disposed in closely spaced relation to the inner surface of said display screen and having a generally spherical curvature and a plurality of spaced apertures, wherein each electron beam is directed through selected ones of said apertures and is incident upon selected ones of the phosphor deposits on said display screen for providing one of the primary colors of red, green or blue of the video image, wherein said apertures are arranged in vertical columns and horizontal rows, with apertures in one row being in different columns than are apertures in adjacent rows and with the vertical spacing between adjacent apertures not within the same column being the vertical pitch of the apertures, wherein shadow mask apertures through which electron beams are directed onto the first inner area of the display screen have a first vertical pitch P.sub.v 1 and shadow mask apertures through which electron beams are directed onto the second outer area of the display screen have a second vertical pitch P.sub.v 2, where P.sub.v 1>P.sub.v 2,wherein the first vertical pitch P.sub.v 1 and the second vertical pitch P.sub.v 2 are each respective quadratic functions of a distance X from a vertical centerline of said display screen.