Matsushita Electronics Corporation

Matsushita Electric Industrial Co., Ltd.

Masamichi Kimura

Shigeya Ashizaki

Tsutomu Utsumi

Takashi Kinoshita

Yoshikazu Demi

Mutsuo Masuda

Shiro Kashihara

Atsushi Hosokawa

Masato Taniguchi

Masao Tokunaga

Chikayoshi Ninagawa

The color cathode ray tube according to the present invention can improve the brightness without compromising strength by making the bridge width in one-dimensional tension type shadow mask narrower to a certain degree. The color cathode ray tube has a color selection electrode, the color selection electrode including a pair of supports facing each other; a shadow mask provided with a plurality of slot apertures, the shadow mask being stretched and fixed by the pair of supports; and elastic members arranged between the supports, and holding the supports. Bridges between vertically adjacent slot apertures are formed on the shadow mask. Defining the bridge width W as the largest vertical width of a bridge, the narrowest bridge width Wmin is in a range of 3-10% of a vertical pitch of the slot apertures. With this configuration, the necessary strength can be ensured, and the brightness can be improved without compromising strength, because the bridge widths W can be made narrower.

Color cathode ray tube with tensioned shadow mask

The color cathode-ray tube comprises a glass bulb, a shadow mask, a deflection yoke, and an electron-beam shifting device. The glass bulb comprises a face-plate with stripe-like phosphors for a plurality of colors formed on its inner face by a printing method, a funnel portion connected to the rear part of the face-plate, and a neck portion formed at the rear of the funnel portion. Inside the neck portion, an inline electron gun is provided for emitting electron beams. The shadow mask comprises a plurality of openings disposed corresponding to the stripe direction of the phosphors for each color on the face-plate. The deflection yoke is provided on the peripheral surfaces of the funnel portion and the neck portion. The electron-beam shifting device is provided on the peripheral surface of the neck portion for shifting the deflection center of the electron beams in the inline-alignment direction of the electron beams. The phosphors are formed by the printing method, thus reducing the costs. Furthermore, the electron-beam shifting device is provided, thus ensuring accurate color reproduction.

Color cathode-ray tube

Welding is conducted by rolling a roller electrode of a roller-type resistance welder while contacting an electrode surface of the roller electrode against an outer edge of the mask frame via the shadow mask. This method eliminates the need for complex control, and allows smooth and reliable welding at predetermined positions with a simple configuration. By forming the weld nugget on the side of the edge, a flat portion remains when the shadow mask is torn off the mask frame in case of a failure of the shadow mask. Thus, a second welding with a flat portion of the original height is possible, and the mask frame can be reused with the same precision for the welding position.

Method for manufacturing a color cathode ray tube

A method for manufacturing a color cathode ray tube capable of surely applying a predetermined tension force to a shadow mask and preventing the generation of wrinkles and a manufacturing apparatus of the color cathode ray tube. The method includes applying a compression force to a mask frame formed in a frame shape in the direction in which a gap between at least a pair of facing sides is reduced; and welding and fixing a shadow mask to the upper surface of the mask frame with a tension force applied in the direction opposite to the compression force. In this method, a place to which the compression force is applied is the upper end of the external surface of the mask frame. Thus, a repulsion force in the direction in which a shadow mask is stretched can surely be obtained after the compression force is released, as compared with the case where the same level of compression force is applied to the lower end. Consequently, it is possible to prevent the deterioration of the tension force of the shadow mask.

Method for manufacturing color cathode ray tube and manufacturing

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 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

An electron gun has five grids (G.sub.1, G.sub.2, G.sub.3, G.sub.4, G.sub.5), and an additional grid (G.sub.2s) is disposed between the second grid and the third grid (G.sub.3) and is impressed with a potential lower than that of the second grid (G.sub.2), and a trimming electrode (G.sub.5a) with a trimming aperture 14 is provided in the fifth grid (G.sub.5), and by trimming the outer shell part of the electron beam having crossed the electron gun axis twice a very small beam spot is produced.

Cathode ray tube apparatus

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

In a bistable direct-view storage tube capable of storing two different images simultaneously and displaying them in different colors, a target electrode or a storage surface comprising an array of red-light-emitting phosphor strips, an array of green-light-emitting phosphor strips interlaced or interleaved with the red-light-emitting phosphor strips, first and second conductor films in the form of a comb with each tooth surrounding each of the phosphor strips and being in electrical contact therewith, each tooth being in the form of a ladder with parallel-side-piece strips and cross-piece strips which divide each phosphor strip into a plurality of substantially equally spaced phosphor lands, whereby every phosphor land can be kept impressed with a predetermined bias voltage even when any of the teeth is electrically damaged.

Direct-view storage tube with multiple path target electrode

In an electron gun for a cathode-ray tube of the type wherein a cathode, control grid electrode, an accelerating electrode and first and second cylindrical electrodes are disposed in the order named and supported and electrically insulated from each other by electrically insulating rods within a neck portion of an envelope, whereby a main electron lens is formed between said first and second cylindrical electrodes, the second cylindrical electrode comprises an enlarged diameter portion and a reduced diameter end portion which is closer to the cathode and is supported by one end of each of the supporting rods; and the first cylindrical electrode has (1) a neck portion which is extended through the reduced diameter end portion of the second cylindrical electrode coaxially thereof and radially inwardly spaced apart therefrom, and (2) an enlarged diameter front portion which has the diameter greater than that of said neck portion, is extended coaxially therefrom into said enlarged diameter portion of said second cylindrical electrode.

Growing community of inventors

Ibaraki, Japan

Masamichi Kimura