Matsushita Electronics Corporation

Matsushita Electric Industrial Co., Ltd.

Shigeya Ashizaki

Masao Natsuhara

Osamu Konosu

Hideo Muranishi

Masamichi Kimura

Kakuichiro Hosokoshi

Koichi Sugahara

Osamu Adachi

Hiroshi Suzuki

Mutsuo Masuda

Katsuyo Iwasaki

Hiromi Wakasono

Akira Hayashi

Masato Taniguchi

Masao Tokunaga

Chikayoshi Ninagawa

Atsushi Hosokawa

Koichi Sugawara

Yasuyuki Takagi

A shadow mask type color cathode ray tube which has a face panel whose screen face is flattened to more than two times the flatness of the conventional flat panels without reducing the resistance of the glass bulb to outside pressure in spite of its relatively thin glass wall, and has an enhanced reflection characteristic of incident light as well as improved local doming characteristics.

Shadow mask type color cathode ray tube

A shadow mask type color cathode ray tube fitted with an in-line type electron gun having a control grid of a quadrupole structure, wherein the control grid has an elongated rectangular hole having a horizontal diameter H and a vertical diameter V wherein the relationship expressed by 1&lt;H/V&lt;1.4 is established.

Color cathode ray tube gun having control grid of varying thickness

A deflection yoke to be used in a color CRT apparatus having an aspherical face panel (30) has a pair of magnetic members (6,7) disposed on an outer surface of a larger diameter part of a cone shaped coil holding frame (11) in symmetry with respect to a vertical plan including center axis of the coil holding frame (11). Each of magnetic member (6,7) has upper and lower magnetic parts (6b,6c) for distorting vertical deflection magnetic field from barrel shape to pincushion shape, and the upper or lower magnetic parts (6b, or 6c) has protruded magnetic parts (6d or 6e), respectively protruded from the upper or lower magnetic parts (6b or 6c) towards screen part of the color CRT apparatus, for partially correction of pincushion distortion of raster at peripheral part of screen.

Deflection yoke

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

In a color picture tube, curvature of outside face of said face panel is defined by ##EQU1## wherein Z is a distance in a direction of tube axis from an X-Y plane tangential at the center of the face, r is a distance from the center of the face panel to said point therealong, and A and B are constants of positive integers, respectively; thus the face panel excludes point of inflection and the reproduced picture thereon has a flat appearance, without trouble of undesirable doming of shadow mask.

Color picture tube having a face panel with an outer face having a

Making method for a phosphor layer of a small diameter cathode ray tube comprises application of a centrifugal force of above 100G in a direction parallel to the axis of a glass bulb toward its bottom panel to become a face plate, thereby forcedly making sedimentation of phosphor powder onto the inner surface of the bottom panel, and thus, by adoptation of the centrifugal force, a phosphor layer of very fine and dense configuration and uniform thickness is obtainable even using such small medium grain size of phosphor powder of under 4 .mu.m.

Method for making a phosphor layer

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.

In-line electron gun

In a cathode ray tube apparatus having an in-line type electron gun, the focusing grid of the quadrupole electric field (8) which comprises the horizontal-electric-field boosting grids (11) and (11') and the vertical-electric-field boosting grids (12) and (12') is disposed between the first focusing grid (7) and the second focusing grid (9).

Color cathode ray tube apparatus

In-line type electron gun

In a deflection means 11 having a field of pin-cushion type flux distribution, at least a pair of T-shaped magnetic pole pieces 9, 10 are disposed between the front end of an electron gun 2 and the center part of the deflection means 11, thereby to form a barrel type flux distribution, to attain high resolution even at peripheral part of the fluorescent screen.

Cathode ray tube with magnetic pole pieces which support a ring getter

A monochromatic picture tube whose faceplate has a transmittance of 17 to 23% is provided. In order to obtain the same transmittance as described above, black di-iron trioxide is coated on phosphor grains to form a phosphor screen on the faceplate. Therefore, a picture on the screen results in contrast without eyestrain.

Monochromatic picture tube

An auxiliary grid which is formed with one or more elongated slits through which pass electron beams is disposed in a prefocusing system in a cathode-ray tube, and a dynamic voltage which varies in level with increase in horizontal deflection angle is applied to the auxiliary grid so that axial asymmetry of the prefocusing system can be increased with increase in the horizontal deflection angle. As a consequence, the beam spot can be maintained substantially in the form of a true circle not only at the center of the screen but also at the portions adjacent to the peripheries thereof. Thus, the resolution at the portions adjacent to the peripheries of the screen can be improved and consequently high-quality images can be represented over the whole surface of the screen.

Cathode-ray tube device

A cathode-ray tube has a phosphor screen which is made by using a mixture of a long persistent phosphor and a short persistent phosphor. A light emission from the short persistent phosphor has a spike figure, so that a light pen can have sufficient sensitivity therefor, and a light emission from the long persistent phosphor is continuous within the one cycle period of the frame frequency, so that flicker is not noticeable.

Cathode-ray tube having a mixture of long and short persistence phosphors

In an in-line electron gun, three apertures, closer to an accelerating electrode, of a focusing electrode, which forms three main electron lenses, are defined by bridging with a partition electrode means two neck portions of a peanut-shaped aperture consisting of a center or inner aperture and two outer apertures which partially overlap the center or inner aperture and are contiguous therewith, thus forming a continuous aperture in the form of a peanut pod having three seeds.

The invention discloses a method and apparatus for manufacture of color television picture tubes of the type having a shadow mask with a multiplicity of slots, and more particularly for selectively exposing a light sensitive film uniformly coated over the inner surface of a face-panel in order to form the temporary dots or strips. The exposure light source is rotated in the form of a ring while it is displaced relative to the light sensitive film in the longitudinal direction of the slots in a shadow mask, whereby the spacing in the longitudinal direction between the adjacent exposed areas or light images projected may be advantageously reduced without reducing the spacing in the longitudinal direction between the adjacent slots in the shadow mask; that is, the width of the bridge therebetween, so that the color television picture tubes with excellent brightness and contrast characteristics may be provided without adversely affecting the mechanical strength of the shadow mask.

Growing community of inventors

Takatsuki, Japan

Shigeya Ashizaki