Hitachi, Ltd.

Kuniharu Osakabe

Koichi Maruyama

Soichi Sakurai

Kyohei Fukuda

Takeshi Nakayama

Isao Yoshimi

Machio Kawashima

Takehiko Nishimoto

Kozi Takahashi

Takao Kawamura

Kunio Ando

Takeshi Matsuki

Ryoichi Hirota

Satoshi Kawanishi

Sakae Kunitoh

At least one of the focusing electrodes stages disposed between an acceleration electrodes stage and a rear focusing electrodes stage is constituted by first and second grid electrodes, confronting portions thereof having asymmetrical construction with respect to an electron beam axis. A constant focusing voltage is applied to the first grid electrode, and a dynamic focusing voltage gradually increasing or decreasing from the constant focusing voltage as the degree of beam deflection increases is applied to the second grid electrode.

Cathode ray tube

An improved in-line type electromagnetic focusing cathode-ray tube which comprises magnetic yokes, a focusing magnetic field generating permanent magnet, a deflecting magnetic field control element and a cup-shaped spacer member for separating the magnetic yokes from the deflecting magnetic field control element. The deflecting magnetic field control element is disposed at a distance l.gtoreq.0.26 D from an end of the magnetic yoke closest to a fluorescent screen, where D is an outer diameter of the magnetic yoke, so that a beam spot on the fluorescent screen has substantially circular shape to attain an excellent focusing characteristic.

In-line type electromagnetic focusing cathode-ray tube

A color television picture tube of three in-line gun type wherein a ring-shaped ferrite permanent magnet or magnets are disposed around a neck portion of the tube, at least a pair of mutually-opposing pole pieces made of highly permeable magnetic material are provided within the tube neck portion as a part of the gun assembly so as to be magnetized by the ring magnet or magnets and to form an electron beam magnetic focusing lens system. In the picture tube, the pole pieces are each of a substantially elliptical cross section as viewed from a plane perpendicular to the tube axis, and spaces are provided between an inner wall of the tube neck portion and the pole pieces to accommodate support rods for gun assembling. There are selected to fall in particular ranges the ratio of the outer diameter to inner diameter of the permanent magnet, the ratio of the thickness to inner diameter thereof, the ratio of the thickness to gap length between the opposing pole pieces, and the ratio of the tube-axial length of the pole piece disposed on the side of a phosphor screen to the tube-axial length of the pole piece disposed on the side of cathode electrodes.

Magnetic focusing, three in-line gun type color picture tube

An electromagnetic focusing cathode-ray tube in which plural pairs of magnetic material members are arranged within the tube along the tube axis, the magnetic material members in each pair are disposed to oppose each other in the direction of the tube axis with a gap defined therebetween, and the plural magnetic material member pairs and one or more permanent magnet disposed internally or externally of the tube are combined such that magnetic focusing fields having their senses or directions opposite to each other in the direction of the tube axis are formed at the respective gaps associated with the adjacent magnetic material pairs.

Electromagnetic focusing cathode-ray tube

In a magnetic field generator mounted about a neck of a cathode ray tube for focusing an electron beam and made up of a permanent magnet, a magnetic field adjusting mechanism for adjusting field intensity produced by the permanent magnet and a magnetic member adapted to compensate for a temperature characteristic of the permanent magnet, the temperature characteristic compensating member is located at a position not affected by magnetic flux adjusted by the magnetic field adjusting mechanism.

Magnetic field generators for use in electromagnetic focusing type

In a cathode-ray tube provided with a direct-heating type cathode, a transformer through which the cathode is heated is disposed within the bulb of the cathode-ray tube. This improvement eliminates the instability of heating due to the contact resistance caused between the base pins of the cathode-ray tube to which the terminals of the cathode are connected and the socket pins to which the base pins are fitted.

Cathode device for cathode-ray tube

A color picture tube having a shadow mask is disclosed in which, with a view to making occurrence of moire imperceptible, electron beam transmissive apertures of the shadow mask are formed in such an array that a plurality of trains of the electron beam transmissive apertures each arrayed in the vertical direction with a pitch P.sub.y are juxtaposed to one another, wherein, assuming that the order of the harmonics is represented by n and m is an odd number smaller than 2n, there exist the relations (n-0.5)P.sub.l .ltoreq.P.sub.y .ltoreq.(n+0.05)P.sub.l and (m-0.35)P.sub.y /2n.ltoreq..DELTA.y.ltoreq.(m+0.35)P.sub.y /2n among the pitch P.sub.y, pitch P.sub.l of scanning lines and vertical deviation .DELTA.y between two adjacent apertures in the horizontal direction.

Slotted shadow mask having apertures spaced to minimize moire

An in-line stripe type color picture tube comprises an inner magnetic shield member having sufficient shield effect against both individual vertical and horizontal components of the earth magnetism and composite components as well. The inner magnetic shield member prevents unwanted shifts of electron beams to ensure that the positional relationship between a fluorescent screen and landing electron beams may have sufficient tolerances and color blur on the fluorescent screen may be prevented.

Color picture tube with internal funnel shaped magnetic shield

A color picture tube having a shadow mask provided with a plurality of vertical aperture rows arranged as horizontally juxtaposed to one another, each vertical row comprising the electron beam transmissive apertures vertically arranged in line with a predetermined pitch P.sub.y. With a view to making possibly occurring moires imperceptible, the arrangement of the apertures are made such that, when spatial deviation in the vertical positions between any two apertures in the horizontally adjacent aperture rows is represented by .DELTA.y, there may be included combinations of at least two different type aperture rows of different deviations .DELTA.y which satisfy the following condition ##EQU1## at least when n is equal to 1, 2, 3 or 4 and k is an odd number smaller than 2n.

Color picture tube with shadow mask

A color misalignment correction device for use in a color picture tube, in which at least two magnets are disposed rotatably and adjustably on the outer peripheral surface of the cathode-ray bulb so as to correct an arc-shaped convergence error appearing in a horizontal direction of the phosphor screen due to a mounting error of the electron guns in the color picture tube or due to a mounting error of the deflection coil assembly on the color picture tube.

Color misalignment correction device for color picture tube

A color picture tube of an in-line type comprises means for deflecting beams of electron emitted from electron guns of the in-line type aligned horizontally such that for the horizontal deflection, the central beam is subjected to a greater deflection than side beams and for the vertical deflection, the side beams are subjected to a greater deflection than the central beam. Two vertical magnetic pole piece plates which are long vertically and thin horizontally are so disposed as to sandwich the central beam near the outlet of the central electron gun in order to weaken horizontal deflection magnetic field acting on the central beam, whereby a portion of the horizontal deflection magnetic flux acting on the central beam is absorbed by the two magnetic pole piece plates. The vertical deflection magnetic field is almost not affected by these vertical magnetic pole piece plates. Further, two horizontal magnetic pole piece plates which are long horizontally and short vertically are so disposed as to sandwich side beams near the outlets of the side electron guns in order to weaken vertical deflection magnetic fields acting on the side beams and to intensity vertical deflection magnetic fields acting on the central beam.

Color picture tube

A correction lens disposed between the exposure light source and a glass panel provided with a shadow mask at the exposure step of manufacturing a color television CRT and adaped to compensate for the tendency of the phosphor stripes being formed in a wavy configuration. The correction lens has such a characteristic that, when the light source is observed through the correction lens at the side of the shadow mask, the light source is viewed as displaced in appearance toward the correction lens by a certain constant distance on the optical axis independently of the viewing angle, whereby the image of a linear light source or the linear moving path of a point source of light is made to extend substantially in parallel with the length of the slot of the shadow mask.

Growing community of inventors

Mobara, Japan

Kuniharu Osakabe