Abstract: A mask-focusing color picture tube comprising an evacuated envelope; means to generate a number of electron beams; a display screen comprising a large number of phosphor stripes luminescing in different colors; a plurality of masks being spaced in the predetermined distance each other, individually having a number of apertures which is arranged in rows and being disposed in the vicinity of said screen, each electron beam being assigned to phosphor stripe of a respective color through said corresponding mask aperture, the improvement comprising, at least one of said plurality of masks having a plurality of projections on at least one side of said mask, said projections being separated each other by the rows of said apertures.

Abstract: In a picture tube comprising an envelope including a phosphor screen and an electron gun generating an electron beam, wherein the electron beam is deflected by magnetic deflecting fields, the electron gun comprising a triode section and a focusing section along a path of the electron beam, the triode sections being provided with an electrode containing a non-circular aperture having major and minor axes of symmetry, the major axis being parallel to a horizontal direction the focusing section having a means for forming an electrostatic focusing lens having a vertical focal length and a horizontal focal length, said vertical focal length more elongated than said horizontal focal length.

Abstract: A cathode ray tube electron gun having an electron beam-generating source and a main lens system for focusing electron beams emitted from said electron beam-generating source, wherein the main lens system comprises at least first, second, third and fourth focusing electrodes arranged coaxially and in the order mentioned an counted from said electron beam-generating source; the first and third focusing electrodes are impressed with substantially the same potential; and the fourth focusing electrode is supplied with a prescribed potential higher than those which are applied to said first and third focusing electrodes.

Abstract: A beam index color cathode ray tube is provided with a screen arranged on the inner surface of a face plate portion and an electron gun arranged in a neck portion thereof. This screen comprises phosphor stripes and index stripes. The electron gun comprises at least a cathode and two electrodes forming a focusing lens. The focusing lens of the electron gun is formed between at least two electrodes provided with transversely elongate openings having their direction of elongation in the width direction of the phosphor stripes or index stripes.

Abstract: Disclosed is an in-line type color picture tube apparatus which comprises an in-line type color picture tube including a phosphor screen for displaying a substantially rectangular picture with horizontal, vertical, and diagonal axes and an in-line electron gun arranged in parallel with the horizontal axis so as to be allowed to cast electron beams on the phosphor screen to reproduce a color image, a deflection yoke disposed around the outer periphery of the tube and generating such a magnetic field that may give positive isotropic astigmatism to the electron beams when the electron beams are deflected along the horizontal axis, may give negative isotropic astigmatism to the electron beams when the electron beams are deflected along the vertical axis, and may give negative anisotropic astigmatism to the electron beams when the electron beams are deflected along the diagonal axes, and a correction deflection element formed of a plurality of permanent magnets arranged in the vicinity of the end portion of the de

Abstract: A beam-index tube apparatus comprising a beam-index picture tube provided with an electron gun to generate an electron beam of an oval cross-section, a deflecting device having a deflecting yoke for deflecting the electron beam, and correcting elements provided in the proximity of a front end of the deflecting yoke and positioned corresponding to the horizontal axis and the diagonal axes of the picture tube. The correcting elements act upon the electron beam in a manner such that the rotating of the diagonally deflected electron beam and widening of the horizontally deflected electron beam are thereby corrected.

Abstract: A beam-indexing color image-presentation cathode ray tube comprises color-phosphor stripes arranged in a regular order and differently responsive to impingement by electron beams to produce light of different colors and index-phosphor stripes arranged to have a predetermined geometric relation to the color-phosphor stripes and responsive to impingement by the electron beams to produce index signals, in which the index-phosphor stripes comprises a first index-phosphor stripe, a second index-phosphor stripe and a third index-phosphor stripe, the pitch of the second index-phosphor stripe is three times as large as the pitch of the third index-phosphor stripe, and the first index-phosphor stripe is wider in its width than the second index-phosphor stripe.

Abstract: In a color cathode ray tube including an electron gun means for projecting three electron beams in an in-line arrangement, there is provided deflection defocus correcting means which are disposed adjacent the side electron beams for neutralizing the deflection defocus of the side beam caused by the non-uniformity of the deflection fields.