Abstract There is disclosed a cathode-ray tube for a color television set employing a plurality of electron guns whose electron beams are arranged to be deflected over a screen on which a color picture is to be reproduced. Between the electron guns and the screen is interposed a shadow mask formed with a multiplicity of apertures through which the electron beams pass to the screen. The spacing of these apertures, measured along the surface of the mask, is so chosen as to be greater at the edge of the mask than at the center thereof. A method of making a shadow mask with this arrangement of apertures is also disclosed. A photosensitive surface is arranged so as to be tangential at its center E with respect to a smaller spherical mask having a uniform pattern of apertures formed therein, the center C of the spherical surface and the center A the spherical mask being disposed on a straight line passing through the point E. The photo sensitive surface is illuminated through the apertures in said mask from a point light source located at a point O on said line so selected that OD/OB is greater than unity, where D is any point on said photo sensitive surface impinged upon by light from O passing through an aperture at the point B.
In a cathode-ray tube comprising a plurality of electron guns, and guns being dispOsed in side-by-side relationship and each producing an electron beam, a screen on which a color picture is to be reproduced, said screen being provided with phosphor dots, means for deflecting said beams in common over said screen, and a shadow mask located between said guns and said screen, said mask being apertured at a multiplicity of points to define passages through which said beams can pass to said screen, the improvement according to which the center-to-center spacing of said passages in both the radial and circumferential directions is greater at the edge of said mask than at the center thereof, and the center-to-center spacing of said phosphor dots in both the radial and circumferential directions is likewise greater at the edge of said screen than at the center thereof.
Claim 2
Dependent Claim
143 words
In a cathode-ray tube comprising a plurality of electron guns, and guns being dispOsed in side-by-side relationship and each producing an electron beam, a screen on which a color picture is to be reproduced, said screen being provided with phosphor dots, means for deflecting said beams in common over said screen, and a shadow mask located between said guns and said screen, said mask being apertured at a multiplicity of points to define passages through which said beams can pass to said screen, the improvement according to which the center-to-center spacing of said passages in both the radial and circumferential directions is greater at the edge of said mask than at the center thereof, and the center-to-center spacing of said phosphor dots in both the radial and circumferential directions is likewise greater at the edge of said screen than at the center thereof.
Claim 3
Dependent Claim
28 words
A cathode-ray tube as claimed in claim 1, wherein said phosphor dots increase in size from the center of said screen and are substantially tangential to one another.