Matsushita Electronics Corporation

Hiroshi Suzuki

Masao Natsuhara

Koichi Sugahara

Noboru Tominaga

Shigeya Ashizaki

Osamu Konosu

Chisato Kurusu

Katsuyo Iwasaki

Hideo Muranishi

Hidekuni Fujisawa

A color cathode ray unit which includes an in-line type electron gun, a deflection yoke disposed on the color CRT so as to generate substantially uniform horizontal and vertical deflection magnetic fields, thereby ensuring that an axially unsymmetrical lens electric field is dynamically generated between a first and a second focusing grid thereby correcting a distortion of electron beams caused by a magnetic field leaking from a dynamic convergence means.

Color cathode ray tube unit

An in-line type electron gun used in a color cathode ray tube apparatus, the electron gun comprising a focusing grid, a final accelerating grid adjacent to the focusing grid, these grids having elongated cylindrical apertures having their majors extending horizontally, a field correction metal plate located in each grid along the elongated aperture, the field correction metal plate having three apertures produced in an in-line arrangement, wherein the central aperture is elongated with a major extending vertically, and the two apertures on each side are circular, the horizontal diameter L.sub.s and the vertical diameter .phi..sub.v having a ratio .phi..sub.v /L.sub.s of 0.49 to 0.6.

In-line type electron gun for a color cathode ray tube

The invention provides an in-line electron gun in which first astigmatic lens fields that are convergent in a horizontal direction and divergent in a vertical direction are produced between a first focusing grid and a second focusing grid, and second astigmatic lens fields that are divergent in a horizontal direction and convergent in a vertical direction are produced upstream of the first focusing grid. The lens magnifications in both horizontal and vertical directions can be made substantially equal, so that it is possible to achieve a satisfactory resolution over the entire area of the phosphor screen and also to prevent moire occurrences.

In-line electron gun

An in-line type cathode ray tube apparatus, is improved to obtain less aberration of beam spots by shaping the electron beam passing apertures (15a, 15b, 15c) in the control grid (11) and those in the accelerating grid (12) into horizontally oblong elliptic shapes, and providing a horizontally oblong electrode means (18) having a rectangle shape active space on the accelerating grid (12) at its down stream side of the electron beam.

Cathode ray tube apparatus

The present invention relates to a cathode ray tube apparatus which can reduce an astigmatism caused from the deflection distortion by providing its focusing grid in two parts and producing a dynamic focusing lens of a quadrupole between the opposing faces of the two focusing grid parts. One focusing grid preferably has vertically disposed oblong through holes, while the other focusing grid preferably has one or more horizontally disposed oblong through holes.

Cathode ray tube apparatus having focusing grids with horizontally and

In an in-line electron gun for a color picture tube, 10c aligned with three cathodes 10a, 10b and 10c, through-holes of a control grid 11 and an accelerating electrode 12 are spaced by a distance S.sub.1 ; distance S.sub.2 between inlet through-holes 13a, 13b and 13c of a first focusing electrode 13 are spaced by a distance S.sub.3 ; outlet through-holes 13d, 13e and 13f of the first focusing electrode 13 and inlet through-holes 14a, 14b and 14c of a second focusing electrode 14 are spaced by a distance S.sub.3 ; outlet through-holes 14d, 14e and 14f of the second focusing electrode 14 and of an anode, 15 are spaced by a distance S.sub.4. The distances are selected to have a relation of S.sub.4 &lt;S.sub.3 &lt;S.sub.1 &lt;S.sub.2, enabling misconvergence to be minimized.

Distance between the second grid (G2) and the third grid (G3) is selected very short and electron beam passing apertures of the second grid (G2) and the third grid (G3) are selected small; the cathode ray tube has small beam spot both at small current and large current operations.

Growing community of inventors

Nagaokakyo, Japan

Hiroshi Suzuki